readd pods

Podfile.lock

@@ -0,0 +1,32 @@
+PODS:
+  - BigInt (5.2.0)
+  - Kingfisher (7.10.0)
+  - SwiftProtobuf (1.25.1)
+  - TrustWalletCore (4.0.8):
+    - TrustWalletCore/Core (= 4.0.8)
+  - TrustWalletCore/Core (4.0.8):
+    - TrustWalletCore/Types
+  - TrustWalletCore/Types (4.0.8):
+    - SwiftProtobuf
+
+DEPENDENCIES:
+  - BigInt
+  - Kingfisher
+  - TrustWalletCore
+
+SPEC REPOS:
+  trunk:
+    - BigInt
+    - Kingfisher
+    - SwiftProtobuf
+    - TrustWalletCore
+
+SPEC CHECKSUMS:
+  BigInt: f668a80089607f521586bbe29513d708491ef2f7
+  Kingfisher: a18f05d3b6d37d8650ee4a3e61d57a28fc6207f6
+  SwiftProtobuf: 69f02cd54fb03201c5e6bf8b76f687c5ef7541a3
+  TrustWalletCore: 1c544d540c37dff1fd7068aa11c06558d0c9e8de
+
+PODFILE CHECKSUM: 0f310e1fc0a68af5ddad91584de979217a389c13
+
+COCOAPODS: 1.13.0

Pods/BigInt/LICENSE.md

@@ -0,0 +1,20 @@
+
+Copyright (c) 2016-2017 Károly Lőrentey
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Pods/BigInt/README.md

@@ -0,0 +1,430 @@
+[![BigInt](https://github.com/attaswift/BigInt/raw/master/images/banner.png)](https://github.com/attaswift/BigInt)
+
+* [Overview](#overview)
+* [API Documentation](#api)
+* [License](#license)
+* [Requirements and Integration](#integration)
+* [Implementation Notes](#notes)
+    * [Full-width multiplication and division primitives](#fullwidth)
+    * [Why is there no generic `BigInt<Digit>` type?](#generics)
+* [Calculation Samples](#samples)
+	* [Obligatory factorial demo](#factorial)
+	* [RSA Cryptography](#rsa)
+	* [Calculating the Digits of π](#pi)
+
+[![Swift 3](https://img.shields.io/badge/Swift-5-blue.svg)](https://developer.apple.com/swift/)
+[![License](https://img.shields.io/badge/licence-MIT-blue.svg)](http://cocoapods.org/pods/BigInt)
+[![Platform](https://img.shields.io/cocoapods/p/BigInt.svg)](http://cocoapods.org/pods/BigInt)
+
+[![Build Status](https://travis-ci.org/attaswift/BigInt.svg?branch=master)](https://travis-ci.org/attaswift/BigInt)
+[![Code Coverage](https://codecov.io/github/attaswift/BigInt/coverage.svg?branch=master)](https://codecov.io/github/attaswift/BigInt?branch=master)
+[![Carthage compatible](https://img.shields.io/badge/Carthage-compatible-4BC51D.svg)](https://github.com/Carthage/Carthage)
+[![Version](https://img.shields.io/cocoapods/v/BigInt.svg)](http://cocoapods.org/pods/BigInt)
+
+## <a name="overview">Overview</a>
+
+This repository provides [integer types of arbitrary width][wiki] implemented
+in 100% pure Swift. The underlying representation is in base 2^64, using `Array<UInt64>`.
+
+[wiki]: https://en.wikipedia.org/wiki/Arbitrary-precision_arithmetic
+
+This module is handy when you need an integer type that's wider than `UIntMax`, but
+you don't want to add [The GNU Multiple Precision Arithmetic Library][GMP]
+as a dependency.
+
+[GMP]: https://gmplib.org
+
+Two big integer types are included: [`BigUInt`][BigUInt] and [`BigInt`][BigInt],
+the latter being the signed variant.
+Both of these are Swift structs with copy-on-write value semantics, and they can be used much
+like any other integer type.
+
+The library provides implementations for some of the most frequently useful functions on
+big integers, including
+
+- All functionality from [`Comparable`][comparison] and [`Hashable`][hashing]
+
+- [The full set of arithmetic operators][addition]: `+`, `-`, `*`, `/`, `%`, `+=`, `-=`, `*=`, `/=`, `%=`
+  - [Addition][addition] and [subtraction][subtraction] have variants that allow for
+    shifting the digits of the second operand on the fly.
+  - Unsigned subtraction will trap when the result would be negative.
+    ([There are variants][subtraction] that return an overflow flag.)
+  - [Multiplication][mul] uses brute force for numbers up to 1024 digits, then switches to Karatsuba's recursive method.
+    (This limit is configurable, see `BigUInt.directMultiplicationLimit`.)
+  - A [fused multiply-add][fused] method is also available, along with other [special-case variants][multiplication].
+  - [Division][division] uses Knuth's Algorithm D, with its 3/2 digits wide quotient approximation.
+    It will trap when the divisor is zero.
+  - [`BigUInt.divide`][divide] returns the quotient and
+    remainder at once; this is faster than calculating them separately.
+
+- [Bitwise operators][bitwise]: `~`, `|`, `&`, `^`, `|=`, `&=`, `^=`, plus the following read-only properties:
+  - [`width`][width]: the minimum number of bits required to store the integer,
+  - [`trailingZeroBitCount`][trailingZeroBitCount]: the number of trailing zero bits in the binary representation,
+  - [`leadingZeroBitCount`][leadingZeroBitCount]: the number of leading zero bits (when the last digit isn't full),
+
+- [Shift operators][shift]: `>>`, `<<`, `>>=`, `<<=`
+
+- Methods to [convert `NSData` to big integers][data] and vice versa.
+
+- Support for [generating random integers][random] of specified maximum width or magnitude.
+
+- Radix conversion to/from [`String`s][radix1] and [big integers][radix2] up to base 36 (using repeated divisions).
+  - Big integers use this to implement `StringLiteralConvertible` (in base 10).
+
+- [`sqrt(n)`][sqrt]: The square root of an integer (using Newton's method).
+
+- [`BigUInt.gcd(n, m)`][GCD]: The greatest common divisor of two integers (Stein's algorithm).
+
+- [`base.power(exponent, modulus)`][powmod]: Modular exponentiation (right-to-left binary method).
+  [Vanilla exponentiation][power] is also available.
+- [`n.inverse(modulus)`][inverse]: Multiplicative inverse in modulo arithmetic (extended Euclidean algorithm).
+- [`n.isPrime()`][prime]: Miller–Rabin primality test.
+
+The implementations are intended to be reasonably efficient, but they are unlikely to be
+competitive with GMP at all, even when I happened to implement an algorithm with same asymptotic
+behavior as GMP. (I haven't performed a comparison benchmark, though.)
+
+The library has 100% unit test coverage. Sadly this does not imply that there are no bugs
+in it.
+
+## <a name="api">API Documentation</a>
+
+Generated API docs are available at http://attaswift.github.io/BigInt/.
+
+## <a name="license">License</a>
+
+BigInt can be used, distributed and modified under [the MIT license][license].
+
+## <a name="integration">Requirements and Integration</a>
+
+BigInt 4.0.0 requires Swift 4.2 (The last version with support for Swift 3.x was BigInt 2.1.0.
+The last version with support for Swift 2 was BigInt 1.3.0.)
+
+| Swift Version | last BigInt Version|
+| ------------- |:-------------------|
+| 3.x           | 2.1.0              |
+| 4.0           | 3.1.0              |
+| 4.2           | 4.0.0              |
+| 5.0           | 5.0.0              |
+
+BigInt deploys to macOS 10.10, iOS 9, watchOS 2 and tvOS 9.
+It has been tested on the latest OS releases only---however, as the module uses very few platform-provided APIs,
+there should be very few issues with earlier versions.
+
+BigInt uses no APIs specific to Apple platforms, so
+it should be easy to port it to other operating systems.
+
+Setup instructions:
+
+- **Swift Package Manager:**
+  Although the Package Manager is still in its infancy, BigInt provides experimental support for it.
+  Add this to the dependency section of your `Package.swift` manifest:
+
+    ```Swift
+    .package(url: "https://github.com/attaswift/BigInt.git", from: "5.0.0")
+    ```
+
+- **CocoaPods:** Put this in your `Podfile`:
+
+    ```Ruby
+    pod 'BigInt', '~> 5.0'
+    ```
+
+- **Carthage:** Put this in your `Cartfile`:
+
+    ```
+    github "attaswift/BigInt" ~> 5.0
+    ```
+
+## <a name="notes">Implementation notes</a>
+
+[`BigUInt`][BigUInt] is a `MutableCollectionType` of its 64-bit digits, with the least significant
+digit at index 0. As a convenience, [`BigUInt`][BigUInt] allows you to subscript it with indexes at
+or above its `count`. [The subscript operator][subscript] returns 0 for out-of-bound `get`s and
+automatically extends the array on out-of-bound `set`s. This makes memory management simpler.
+
+[`BigInt`][BigInt] is just a tiny wrapper around a `BigUInt` [absolute value][abs] and a
+[sign bit][negative], both of which are accessible as public read-write properties.
+
+### <a name="generics">Why is there no generic `BigInt<Digit>` type?</a>
+
+The types provided by `BigInt` are not parametric—this is very much intentional, as
+Swift generics cost us dearly at runtime in this use case. In every approach I tried,
+making arbitrary-precision arithmetic operations work with a generic `Digit` type parameter
+resulted in code that was literally *ten times slower*. If you can make the algorithms generic
+without such a huge performance hit, [please enlighten me][twitter]!
+
+This is an area that I plan to investigate more, as it would be useful to have generic
+implementations for arbitrary-width arithmetic operations. (Polynomial division and decimal bases
+are two examples.) The library already implements double-digit multiplication and division as
+extension methods on a protocol with an associated type requirement; this has not measurably affected
+performance. Unfortunately, the same is not true for `BigUInt`'s methods.
+
+Of course, as a last resort, we could just duplicate the code to create a separate
+generic variant that was slower but more flexible.
+
+[license]: https://github.com/attaswift/BigInt/blob/master/LICENSE.md
+[twitter]: https://twitter.com/lorentey
+[BigUInt]: http://attaswift.github.io/BigInt/Structs/BigUInt.html
+[BigInt]: http://attaswift.github.io/BigInt/Structs/BigInt.html
+[comparison]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/Comparison
+[hashing]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/Hashing
+[addition]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/Addition
+[subtraction]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/Subtraction
+[mul]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/s:ZFV6BigInt7BigUIntoi1mFTS0_S0__S0_
+[fused]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/s:FV6BigInt7BigUInt14multiplyAndAddFTS0_Vs6UInt6410atPositionSi_T_
+[multiplication]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/Multiplication
+[division]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/Division
+[divide]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/s:FV6BigInt7BigUInt7dividedFT2byS0__T8quotientS0_9remainderS0__
+[bitwise]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/Bitwise%20Operations
+[width]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/s:vV6BigInt7BigUInt5widthSi
+[leadingZeroBitCount]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/s:vV6BigInt7BigUInt13leadingZeroBitCountSi
+[trailingZeroBitCount]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/s:vV6BigInt7BigUInt14trailingZeroBitCountSi
+[shift]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/Shift%20Operators
+[data]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/NSData%20Conversion
+[random]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/Random%20Integers
+[radix1]: http://attaswift.github.io/BigInt/Extensions/String.html#/s:FE6BigIntSScFTVS_7BigUInt5radixSi9uppercaseSb_SS
+[radix2]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/s:FV6BigInt7BigUIntcFTSS5radixSi_GSqS0__
+[sqrt]: http://attaswift.github.io/BigInt/Functions.html#/s:F6BigInt4sqrtFVS_7BigUIntS0_
+[GCD]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/s:ZFV6BigInt7BigUInt3gcdFTS0_S0__S0_
+[powmod]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/s:FV6BigInt7BigUInt5powerFTS0_7modulusS0__S0_
+[power]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/s:FV6BigInt7BigUInt5powerFSiS0_
+[inverse]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/s:FV6BigInt7BigUInt7inverseFS0_GSqS0__
+[prime]: http://attaswift.github.io/BigInt/Structs/BigUInt.html#/Primality%20Testing
+[abs]: http://attaswift.github.io/BigInt/Structs/BigInt.html#/s:vV6BigInt6BigInt3absVS_7BigUInt
+[negative]: http://attaswift.github.io/BigInt/Structs/BigInt.html#/s:vV6BigInt6BigInt8negativeSb
+[subscript]: https://github.com/attaswift/BigInt/blob/v2.0.0/Sources/BigUInt.swift#L216-L239
+[fullmuldiv]: https://github.com/attaswift/BigInt/blob/v2.0.0/Sources/BigDigit.swift#L96-L167
+
+
+## <a name="samples">Calculation Samples</a>
+
+### <a name="factorial">Obligatory Factorial Demo</a>
+
+It is easy to use `BigInt` to calculate the factorial function for any integer:
+
+```Swift
+import BigInt
+
+func factorial(_ n: Int) -> BigInt {
+    return (1 ... n).map { BigInt($0) }.reduce(BigInt(1), *)
+}
+
+print(factorial(10))
+==> 362880
+
+print(factorial(100))
+==> 93326215443944152681699238856266700490715968264381621468592963895217599993229915
+    6089414639761565182862536979208272237582511852109168640000000000000000000000
+
+print(factorial(1000))
+==> 40238726007709377354370243392300398571937486421071463254379991042993851239862902
+    05920442084869694048004799886101971960586316668729948085589013238296699445909974
+    24504087073759918823627727188732519779505950995276120874975462497043601418278094
+    64649629105639388743788648733711918104582578364784997701247663288983595573543251
+    31853239584630755574091142624174743493475534286465766116677973966688202912073791
+    43853719588249808126867838374559731746136085379534524221586593201928090878297308
+    43139284440328123155861103697680135730421616874760967587134831202547858932076716
+    91324484262361314125087802080002616831510273418279777047846358681701643650241536
+    91398281264810213092761244896359928705114964975419909342221566832572080821333186
+    11681155361583654698404670897560290095053761647584772842188967964624494516076535
+    34081989013854424879849599533191017233555566021394503997362807501378376153071277
+    61926849034352625200015888535147331611702103968175921510907788019393178114194545
+    25722386554146106289218796022383897147608850627686296714667469756291123408243920
+    81601537808898939645182632436716167621791689097799119037540312746222899880051954
+    44414282012187361745992642956581746628302955570299024324153181617210465832036786
+    90611726015878352075151628422554026517048330422614397428693306169089796848259012
+    54583271682264580665267699586526822728070757813918581788896522081643483448259932
+    66043367660176999612831860788386150279465955131156552036093988180612138558600301
+    43569452722420634463179746059468257310379008402443243846565724501440282188525247
+    09351906209290231364932734975655139587205596542287497740114133469627154228458623
+    77387538230483865688976461927383814900140767310446640259899490222221765904339901
+    88601856652648506179970235619389701786004081188972991831102117122984590164192106
+    88843871218556461249607987229085192968193723886426148396573822911231250241866493
+    53143970137428531926649875337218940694281434118520158014123344828015051399694290
+    15348307764456909907315243327828826986460278986432113908350621709500259738986355
+    42771967428222487575867657523442202075736305694988250879689281627538488633969099
+    59826280956121450994871701244516461260379029309120889086942028510640182154399457
+    15680594187274899809425474217358240106367740459574178516082923013535808184009699
+    63725242305608559037006242712434169090041536901059339838357779394109700277534720
+    00000000000000000000000000000000000000000000000000000000000000000000000000000000
+    00000000000000000000000000000000000000000000000000000000000000000000000000000000
+    00000000000000000000000000000000000000000000000000000000000000000000000000000000
+    00000
+```
+
+Well, I guess that's all right, but it's not very interesting. Let's try something more useful.
+
+### <a name="rsa">RSA Cryptography</a>
+
+The `BigInt` module provides all necessary parts to implement an (overly)
+simple [RSA cryptography system][RSA].
+
+[RSA]: https://en.wikipedia.org/wiki/RSA_(cryptosystem)
+
+Let's start with a simple function that generates a random n-bit prime. The module
+includes a function to generate random integers of a specific size, and also an
+`isPrime` method that performs the Miller–Rabin primality test. These are all we need:
+
+```Swift
+func generatePrime(_ width: Int) -> BigUInt {
+    while true {
+        var random = BigUInt.randomInteger(withExactWidth: width)
+        random |= BigUInt(1)
+        if random.isPrime() {
+            return random
+        }
+    }
+}
+
+let p = generatePrime(1024)
+==> 13308187650642192396256419911012544845370493728424936791561478318443071617242872
+    81980956747087187419914435169914161116601678883358611076800743580556055714173922
+    08406194264346635072293912609713085260354070700055888678514690878149253177960273
+    775659537560220378850112471985434373425534121373466492101182463962031
+
+let q = generatePrime(1024)
+==> 17072954422657145489547308812333368925007949054501204983863958355897172093173783
+    10108226596943999553784252564650624766276133157586733504784616138305701168410157
+    80784336308507083874651158029602582993233111593356512531869546706885170044355115
+    669728424124141763799008880327106952436883614887277350838425336156327
+```
+
+Cool! Now that we have two large primes, we can produce an RSA public/private keypair
+out of them.
+
+```Swift
+typealias Key = (modulus: BigUInt, exponent: BigUInt)
+
+let n = p * q
+==> 22721008120758282530010953362926306641542233757318103044313144976976529789946696
+    15454966720907712515917481418981591379647635391260569349099666410127279690367978
+    81184375533755888994370640857883754985364288413796100527262763202679037134021810
+    57933883525572232242690805678883227791774442041516929419640051653934584376704034
+    63953169772816907280591934423237977258358097846511079947337857778137177570668391
+    57455417707100275487770399281417352829897118140972240757708561027087217205975220
+    02207275447810167397968435583004676293892340103729490987263776871467057582629588
+    916498579594964478080508868267360515953225283461208420137
+
+let e: BigUInt = 65537
+let phi = (p - 1) * (q - 1)
+let d = e.inverse(phi)!     // d * e % phi == 1
+==> 13964664343869014759736350480776837992604500903989703383202366291905558996277719
+    77822086142456362972689566985925179681282432115598451765899180050962461295573831
+    37069237934291884106584820998146965085531433195106686745474222222620986858696591
+    69836532468835154412554521152103642453158895363417640676611704542784576974374954
+    45789456921660619938185093118762690200980720312508614337759620606992462563490422
+    76669559556568917533268479190948959560397579572761529852891246283539604545691244
+    89999692877158676643042118662613875863504016129837099223040687512684532694527109
+    80742873307409704484365002175294665608486688146261327793
+
+let publicKey: Key = (n, e)
+let privateKey: Key = (n, d)
+```
+
+In RSA, modular exponentiation is used to encrypt (and decrypt) messages.
+
+```Swift
+func encrypt(_ message: BigUInt, key: Key) -> BigUInt {
+    return message.power(key.exponent, modulus: key.modulus)
+}
+```
+
+Let's try out our new keypair by converting a string into UTF-8, interpreting
+the resulting binary representation as a big integer, and encrypting it with the
+public key. `BigUInt` has an initializer that takes an `NSData`, so this is pretty
+easy to do:
+
+```Swift
+let secret: BigUInt = BigUInt("Arbitrary precision arithmetic is fun!".dataUsingEncoding(NSUTF8StringEncoding)!)
+==> 83323446846105976078466731524728681905293067701804838925389198929123912971229457
+    68818568737
+
+let cyphertext = encrypt(secret, key: publicKey)
+==> 95186982543485985200666516508066093880038842892337880561554910904277290917831453
+    54854954722744805432145474047391353716305176389470779020645959135298322520888633
+    61674945129099575943384767330342554525120384485469428048962027149169876127890306
+    77028183904699491962050888974524603226290836984166164759586952419343589385279641
+    47999991283152843977988979846238236160274201261075188190509539751990119132013021
+    74866638595734222867005089157198503204192264814750832072844208520394603054901706
+    06024394731371973402595826456435944968439153664617188570808940022471990638468783
+    49208193955207336172861151720299024935127021719852700882
+```
+
+Well, it looks encrypted all right, but can we get the original message back?
+In theory, encrypting the cyphertext with the private key returns the original message.
+Let's see:
+
+```Swift
+let plaintext = encrypt(cyphertext, key: privateKey)
+==> 83323446846105976078466731524728681905293067701804838925389198929123912971229457
+    68818568737
+
+let received = String(data: plaintext.serialize(), encoding: NSUTF8StringEncoding)
+==> "Arbitrary precision arithmetic is fun!"
+```
+
+Yay! This is truly terrific, but please don't use this example code in an actual
+cryptography system. RSA has lots of subtle (and some not so subtle) complications
+that we ignored to keep this example short.
+
+### <a name="pi">Calculating the Digits of π</a>
+
+Another fun activity to try with `BigInt`s is to generate the digits of π.
+Let's try implementing [Jeremy Gibbon's spigot algorithm][spigot].
+This is a rather slow algorithm as π-generators go, but it makes up for it with its grooviness
+factor: it's remarkably short, it only uses (big) integer arithmetic, and every iteration
+produces a single new digit in the base-10 representation of π. This naturally leads to an
+implementation as an infinite `GeneratorType`:
+
+[spigot]: http://www.cs.ox.ac.uk/jeremy.gibbons/publications/spigot.pdf
+
+```Swift
+func digitsOfPi() -> AnyGenerator<Int> {
+    var q: BigUInt = 1
+    var r: BigUInt = 180
+    var t: BigUInt = 60
+    var i: UInt64 = 2 // Does not overflow until digit #826_566_842
+    return AnyIterator {
+        let u: UInt64 = 3 * (3 * i + 1) * (3 * i + 2)
+        let y = (q.multiplied(byDigit: 27 * i - 12) + 5 * r) / (5 * t)
+        (q, r, t) = (
+            10 * q.multiplied(byDigit: i * (2 * i - 1)),
+            10 * (q.multiplied(byDigit: 5 * i - 2) + r - y * t).multiplied(byDigit: u),
+            t.multiplied(byDigit: u))
+        i += 1
+        return Int(y[0])
+    }
+}
+```
+
+Well, that was surprisingly easy. But does it work? Of course it does!
+
+```Swift
+var digits = "π ≈ "
+var count = 0
+for digit in digitsOfPi() {
+    assert(digit < 10)
+    digits += String(digit)
+    count += 1
+    if count == 1 { digits += "." }
+    if count == 1000 { break }
+}
+
+digits
+==> π ≈ 3.14159265358979323846264338327950288419716939937510582097494459230781640628
+    62089986280348253421170679821480865132823066470938446095505822317253594081284811
+    17450284102701938521105559644622948954930381964428810975665933446128475648233786
+    78316527120190914564856692346034861045432664821339360726024914127372458700660631
+    55881748815209209628292540917153643678925903600113305305488204665213841469519415
+    11609433057270365759591953092186117381932611793105118548074462379962749567351885
+    75272489122793818301194912983367336244065664308602139494639522473719070217986094
+    37027705392171762931767523846748184676694051320005681271452635608277857713427577
+    89609173637178721468440901224953430146549585371050792279689258923542019956112129
+    02196086403441815981362977477130996051870721134999999837297804995105973173281609
+    63185950244594553469083026425223082533446850352619311881710100031378387528865875
+    33208381420617177669147303598253490428755468731159562863882353787593751957781857
+    780532171226806613001927876611195909216420198
+```
+
+Now go and have some fun with big integers on your own!

Pods/BigInt/Sources/Addition.swift

@@ -0,0 +1,126 @@
+//
+//  Addition.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-03.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension BigUInt {
+    //MARK: Addition
+    
+    /// Add `word` to this integer in place.
+    /// `word` is shifted `shift` words to the left before being added.
+    ///
+    /// - Complexity: O(max(count, shift))
+    internal mutating func addWord(_ word: Word, shiftedBy shift: Int = 0) {
+        precondition(shift >= 0)
+        var carry = word
+        var i = shift
+        while carry > 0 {
+            let (d, c) = self[i].addingReportingOverflow(carry)
+            self[i] = d
+            carry = (c ? 1 : 0)
+            i += 1
+        }
+    }
+
+    /// Add the digit `d` to this integer and return the result.
+    /// `d` is shifted `shift` words to the left before being added.
+    ///
+    /// - Complexity: O(max(count, shift))
+    internal func addingWord(_ word: Word, shiftedBy shift: Int = 0) -> BigUInt {
+        var r = self
+        r.addWord(word, shiftedBy: shift)
+        return r
+    }
+
+    /// Add `b` to this integer in place.
+    /// `b` is shifted `shift` words to the left before being added.
+    ///
+    /// - Complexity: O(max(count, b.count + shift))
+    internal mutating func add(_ b: BigUInt, shiftedBy shift: Int = 0) {
+        precondition(shift >= 0)
+        var carry = false
+        var bi = 0
+        let bc = b.count
+        while bi < bc || carry {
+            let ai = shift + bi
+            let (d, c) = self[ai].addingReportingOverflow(b[bi])
+            if carry {
+                let (d2, c2) = d.addingReportingOverflow(1)
+                self[ai] = d2
+                carry = c || c2
+            }
+            else {
+                self[ai] = d
+                carry = c
+            }
+            bi += 1
+        }
+    }
+
+    /// Add `b` to this integer and return the result.
+    /// `b` is shifted `shift` words to the left before being added.
+    ///
+    /// - Complexity: O(max(count, b.count + shift))
+    internal func adding(_ b: BigUInt, shiftedBy shift: Int = 0) -> BigUInt {
+        var r = self
+        r.add(b, shiftedBy: shift)
+        return r
+    }
+
+    /// Increment this integer by one. If `shift` is non-zero, it selects
+    /// the word that is to be incremented.
+    ///
+    /// - Complexity: O(count + shift)
+    internal mutating func increment(shiftedBy shift: Int = 0) {
+        self.addWord(1, shiftedBy: shift)
+    }
+
+    /// Add `a` and `b` together and return the result.
+    ///
+    /// - Complexity: O(max(a.count, b.count))
+    public static func +(a: BigUInt, b: BigUInt) -> BigUInt {
+        return a.adding(b)
+    }
+
+    /// Add `a` and `b` together, and store the sum in `a`.
+    ///
+    /// - Complexity: O(max(a.count, b.count))
+    public static func +=(a: inout BigUInt, b: BigUInt) {
+        a.add(b, shiftedBy: 0)
+    }
+}
+
+extension BigInt {
+    /// Add `a` to `b` and return the result.
+    public static func +(a: BigInt, b: BigInt) -> BigInt {
+        switch (a.sign, b.sign) {
+        case (.plus, .plus):
+            return BigInt(sign: .plus, magnitude: a.magnitude + b.magnitude)
+        case (.minus, .minus):
+            return BigInt(sign: .minus, magnitude: a.magnitude + b.magnitude)
+        case (.plus, .minus):
+            if a.magnitude >= b.magnitude {
+                return BigInt(sign: .plus, magnitude: a.magnitude - b.magnitude)
+            }
+            else {
+                return BigInt(sign: .minus, magnitude: b.magnitude - a.magnitude)
+            }
+        case (.minus, .plus):
+            if b.magnitude >= a.magnitude {
+                return BigInt(sign: .plus, magnitude: b.magnitude - a.magnitude)
+            }
+            else {
+                return BigInt(sign: .minus, magnitude: a.magnitude - b.magnitude)
+            }
+        }
+    }
+
+    /// Add `b` to `a` in place.
+    public static func +=(a: inout BigInt, b: BigInt) {
+        a = a + b
+    }
+}
+

Pods/BigInt/Sources/BigInt.swift

@@ -0,0 +1,74 @@
+//
+//  BigInt.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2015-12-27.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+//MARK: BigInt
+
+/// An arbitary precision signed integer type, also known as a "big integer".
+///
+/// Operations on big integers never overflow, but they might take a long time to execute.
+/// The amount of memory (and address space) available is the only constraint to the magnitude of these numbers.
+///
+/// This particular big integer type uses base-2^64 digits to represent integers.
+///
+/// `BigInt` is essentially a tiny wrapper that extends `BigUInt` with a sign bit and provides signed integer
+/// operations. Both the underlying absolute value and the negative/positive flag are available as read-write 
+/// properties.
+///
+/// Not all algorithms of `BigUInt` are available for `BigInt` values; for example, there is no square root or
+/// primality test for signed integers. When you need to call one of these, just extract the absolute value:
+///
+/// ```Swift
+/// BigInt(255).abs.isPrime()   // Returns false
+/// ```
+///
+public struct BigInt: SignedInteger {
+    public enum Sign {
+        case plus
+        case minus
+    }
+
+    public typealias Magnitude = BigUInt
+
+    /// The type representing a digit in `BigInt`'s underlying number system.
+    public typealias Word = BigUInt.Word
+    
+    public static var isSigned: Bool {
+        return true
+    }
+
+    /// The absolute value of this integer.
+    public var magnitude: BigUInt
+
+    /// True iff the value of this integer is negative.
+    public var sign: Sign
+
+    /// Initializes a new big integer with the provided absolute number and sign flag.
+    public init(sign: Sign, magnitude: BigUInt) {
+        self.sign = (magnitude.isZero ? .plus : sign)
+        self.magnitude = magnitude
+    }
+
+    /// Return true iff this integer is zero.
+    ///
+    /// - Complexity: O(1)
+    public var isZero: Bool {
+        return magnitude.isZero
+    }
+
+    /// Returns `-1` if this value is negative and `1` if it’s positive; otherwise, `0`.
+    ///
+    /// - Returns: The sign of this number, expressed as an integer of the same type.
+    public func signum() -> BigInt {
+        switch sign {
+        case .plus:
+            return isZero ? 0 : 1
+        case .minus:
+            return -1
+        }
+    }
+}

Pods/BigInt/Sources/BigUInt.swift

@@ -0,0 +1,386 @@
+//
+//  BigUInt.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2015-12-26.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+/// An arbitary precision unsigned integer type, also known as a "big integer".
+///
+/// Operations on big integers never overflow, but they may take a long time to execute.
+/// The amount of memory (and address space) available is the only constraint to the magnitude of these numbers.
+///
+/// This particular big integer type uses base-2^64 digits to represent integers; you can think of it as a wrapper
+/// around `Array<UInt64>`. (In fact, `BigUInt` only uses an array if there are more than two digits.)
+public struct BigUInt: UnsignedInteger {
+    /// The type representing a digit in `BigUInt`'s underlying number system.
+    public typealias Word = UInt
+
+    /// The storage variants of a `BigUInt`.
+    enum Kind {
+        /// Value consists of the two specified words (low and high). Either or both words may be zero.
+        case inline(Word, Word)
+        /// Words are stored in a slice of the storage array.
+        case slice(from: Int, to: Int)
+        /// Words are stored in the storage array.
+        case array
+    }
+
+    internal fileprivate (set) var kind: Kind // Internal for testing only
+    internal fileprivate (set) var storage: [Word] // Internal for testing only; stored separately to prevent COW copies
+
+    /// Initializes a new BigUInt with value 0.
+    public init() {
+        self.kind = .inline(0, 0)
+        self.storage = []
+    }
+
+    internal init(word: Word) {
+        self.kind = .inline(word, 0)
+        self.storage = []
+    }
+
+    internal init(low: Word, high: Word) {
+        self.kind = .inline(low, high)
+        self.storage = []
+    }
+
+    /// Initializes a new BigUInt with the specified digits. The digits are ordered from least to most significant.
+    public init(words: [Word]) {
+        self.kind = .array
+        self.storage = words
+        normalize()
+    }
+
+    internal init(words: [Word], from startIndex: Int, to endIndex: Int) {
+        self.kind = .slice(from: startIndex, to: endIndex)
+        self.storage = words
+        normalize()
+    }
+}
+
+extension BigUInt {
+    public static var isSigned: Bool {
+        return false
+    }
+
+    /// Return true iff this integer is zero.
+    ///
+    /// - Complexity: O(1)
+    var isZero: Bool {
+        switch kind {
+        case .inline(0, 0): return true
+        case .array: return storage.isEmpty
+        default:
+            return false
+        }
+    }
+
+    /// Returns `1` if this value is, positive; otherwise, `0`.
+    ///
+    /// - Returns: The sign of this number, expressed as an integer of the same type.
+    public func signum() -> BigUInt {
+        return isZero ? 0 : 1
+    }
+}
+
+extension BigUInt {
+    mutating func ensureArray() {
+        switch kind {
+        case let .inline(w0, w1):
+            kind = .array
+            storage = w1 != 0 ? [w0, w1]
+                : w0 != 0 ? [w0]
+                : []
+        case let .slice(from: start, to: end):
+            kind = .array
+            storage = Array(storage[start ..< end])
+        case .array:
+            break
+        }
+    }
+
+    var capacity: Int {
+        guard case .array = kind else { return 0 }
+        return storage.capacity
+    }
+
+    mutating func reserveCapacity(_ minimumCapacity: Int) {
+        switch kind {
+        case let .inline(w0, w1):
+            kind = .array
+            storage.reserveCapacity(minimumCapacity)
+            if w1 != 0 {
+                storage.append(w0)
+                storage.append(w1)
+            }
+            else if w0 != 0 {
+                storage.append(w0)
+            }
+        case let .slice(from: start, to: end):
+            kind = .array
+            var words: [Word] = []
+            words.reserveCapacity(Swift.max(end - start, minimumCapacity))
+            words.append(contentsOf: storage[start ..< end])
+            storage = words
+        case .array:
+            storage.reserveCapacity(minimumCapacity)
+        }
+    }
+
+    /// Gets rid of leading zero digits in the digit array and converts slices into inline digits when possible.
+    internal mutating func normalize() {
+        switch kind {
+        case .slice(from: let start, to: var end):
+            assert(start >= 0 && end <= storage.count && start <= end)
+            while start < end, storage[end - 1] == 0 {
+                end -= 1
+            }
+            switch end - start {
+            case 0:
+                kind = .inline(0, 0)
+                storage = []
+            case 1:
+                kind = .inline(storage[start], 0)
+                storage = []
+            case 2:
+                kind = .inline(storage[start], storage[start + 1])
+                storage = []
+            case storage.count:
+                assert(start == 0)
+                kind = .array
+            default:
+                kind = .slice(from: start, to: end)
+            }
+        case .array where storage.last == 0:
+            while storage.last == 0 {
+                storage.removeLast()
+            }
+        default:
+            break
+        }
+    }
+
+    /// Set this integer to 0 without releasing allocated storage capacity (if any).
+    mutating func clear() {
+        self.load(0)
+    }
+
+    /// Set this integer to `value` by copying its digits without releasing allocated storage capacity (if any).
+    mutating func load(_ value: BigUInt) {
+        switch kind {
+        case .inline, .slice:
+            self = value
+        case .array:
+            self.storage.removeAll(keepingCapacity: true)
+            self.storage.append(contentsOf: value.words)
+        }
+    }
+}
+
+extension BigUInt {
+    //MARK: Collection-like members
+
+    /// The number of digits in this integer, excluding leading zero digits.
+    var count: Int {
+        switch kind {
+        case let .inline(w0, w1):
+            return w1 != 0 ? 2
+                : w0 != 0 ? 1
+                : 0
+        case let .slice(from: start, to: end):
+            return end - start
+        case .array:
+            return storage.count
+        }
+    }
+
+    /// Get or set a digit at a given index.
+    ///
+    /// - Note: Unlike a normal collection, it is OK for the index to be greater than or equal to `endIndex`.
+    ///   The subscripting getter returns zero for indexes beyond the most significant digit.
+    ///   Setting these extended digits automatically appends new elements to the underlying digit array.
+    /// - Requires: index >= 0
+    /// - Complexity: The getter is O(1). The setter is O(1) if the conditions below are true; otherwise it's O(count).
+    ///    - The integer's storage is not shared with another integer
+    ///    - The integer wasn't created as a slice of another integer
+    ///    - `index < count`
+    subscript(_ index: Int) -> Word {
+        get {
+            precondition(index >= 0)
+            switch (kind, index) {
+            case (.inline(let w0, _), 0): return w0
+            case (.inline(_, let w1), 1): return w1
+            case (.slice(from: let start, to: let end), _) where index < end - start:
+                return storage[start + index]
+            case (.array, _) where index < storage.count:
+                return storage[index]
+            default:
+                return 0
+            }
+        }
+        set(word) {
+            precondition(index >= 0)
+            switch (kind, index) {
+            case let (.inline(_, w1), 0):
+                kind = .inline(word, w1)
+            case let (.inline(w0, _), 1):
+                kind = .inline(w0, word)
+            case let (.slice(from: start, to: end), _) where index < end - start:
+                replace(at: index, with: word)
+            case (.array, _) where index < storage.count:
+                replace(at: index, with: word)
+            default:
+                extend(at: index, with: word)
+            }
+        }
+    }
+
+    private mutating func replace(at index: Int, with word: Word) {
+        ensureArray()
+        precondition(index < storage.count)
+        storage[index] = word
+        if word == 0, index == storage.count - 1 {
+            normalize()
+        }
+    }
+
+    private mutating func extend(at index: Int, with word: Word) {
+        guard word != 0 else { return }
+        reserveCapacity(index + 1)
+        precondition(index >= storage.count)
+        storage.append(contentsOf: repeatElement(0, count: index - storage.count))
+        storage.append(word)
+    }
+
+    /// Returns an integer built from the digits of this integer in the given range.
+    internal func extract(_ bounds: Range<Int>) -> BigUInt {
+        switch kind {
+        case let .inline(w0, w1):
+            let bounds = bounds.clamped(to: 0 ..< 2)
+            if bounds == 0 ..< 2 {
+                return BigUInt(low: w0, high: w1)
+            }
+            else if bounds == 0 ..< 1 {
+                return BigUInt(word: w0)
+            }
+            else if bounds == 1 ..< 2 {
+                return BigUInt(word: w1)
+            }
+            else {
+                return BigUInt()
+            }
+        case let .slice(from: start, to: end):
+            let s = Swift.min(end, start + Swift.max(bounds.lowerBound, 0))
+            let e = Swift.max(s, (bounds.upperBound > end - start ? end : start + bounds.upperBound))
+            return BigUInt(words: storage, from: s, to: e)
+        case .array:
+            let b = bounds.clamped(to: storage.startIndex ..< storage.endIndex)
+            return BigUInt(words: storage, from: b.lowerBound, to: b.upperBound)
+        }
+    }
+
+    internal func extract<Bounds: RangeExpression>(_ bounds: Bounds) -> BigUInt where Bounds.Bound == Int {
+        return self.extract(bounds.relative(to: 0 ..< Int.max))
+    }
+}
+
+extension BigUInt {
+    internal mutating func shiftRight(byWords amount: Int) {
+        assert(amount >= 0)
+        guard amount > 0 else { return }
+        switch kind {
+        case let .inline(_, w1) where amount == 1:
+            kind = .inline(w1, 0)
+        case .inline(_, _):
+            kind = .inline(0, 0)
+        case let .slice(from: start, to: end):
+            let s = start + amount
+            if s >= end {
+                kind = .inline(0, 0)
+            }
+            else {
+                kind = .slice(from: s, to: end)
+                normalize()
+            }
+        case .array:
+            if amount >= storage.count {
+                storage.removeAll(keepingCapacity: true)
+            }
+            else {
+                storage.removeFirst(amount)
+            }
+        }
+    }
+
+    internal mutating func shiftLeft(byWords amount: Int) {
+        assert(amount >= 0)
+        guard amount > 0 else { return }
+        guard !isZero else { return }
+        switch kind {
+        case let .inline(w0, 0) where amount == 1:
+            kind = .inline(0, w0)
+        case let .inline(w0, w1):
+            let c = (w1 == 0 ? 1 : 2)
+            storage.reserveCapacity(amount + c)
+            storage.append(contentsOf: repeatElement(0, count: amount))
+            storage.append(w0)
+            if w1 != 0 {
+                storage.append(w1)
+            }
+            kind = .array
+        case let .slice(from: start, to: end):
+            var words: [Word] = []
+            words.reserveCapacity(amount + count)
+            words.append(contentsOf: repeatElement(0, count: amount))
+            words.append(contentsOf: storage[start ..< end])
+            storage = words
+            kind = .array
+        case .array:
+            storage.insert(contentsOf: repeatElement(0, count: amount), at: 0)
+        }
+    }
+}
+
+extension BigUInt {
+    //MARK: Low and High
+    
+    /// Split this integer into a high-order and a low-order part.
+    ///
+    /// - Requires: count > 1
+    /// - Returns: `(low, high)` such that 
+    ///   - `self == low.add(high, shiftedBy: middleIndex)`
+    ///   - `high.width <= floor(width / 2)`
+    ///   - `low.width <= ceil(width / 2)`
+    /// - Complexity: Typically O(1), but O(count) in the worst case, because high-order zero digits need to be removed after the split.
+    internal var split: (high: BigUInt, low: BigUInt) {
+        precondition(count > 1)
+        let mid = middleIndex
+        return (self.extract(mid...), self.extract(..<mid))
+    }
+
+    /// Index of the digit at the middle of this integer.
+    ///
+    /// - Returns: The index of the digit that is least significant in `self.high`.
+    internal var middleIndex: Int {
+        return (count + 1) / 2
+    }
+
+    /// The low-order half of this BigUInt.
+    ///
+    /// - Returns: `self[0 ..< middleIndex]`
+    /// - Requires: count > 1
+    internal var low: BigUInt {
+        return self.extract(0 ..< middleIndex)
+    }
+
+    /// The high-order half of this BigUInt.
+    ///
+    /// - Returns: `self[middleIndex ..< count]`
+    /// - Requires: count > 1
+    internal var high: BigUInt {
+        return self.extract(middleIndex ..< count)
+    }
+}
+

Pods/BigInt/Sources/Bitwise Ops.swift

@@ -0,0 +1,121 @@
+//
+//  Bitwise Ops.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-03.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+//MARK: Bitwise Operations
+
+extension BigUInt {
+    /// Return the ones' complement of `a`.
+    ///
+    /// - Complexity: O(a.count)
+    public static prefix func ~(a: BigUInt) -> BigUInt {
+        return BigUInt(words: a.words.map { ~$0 })
+    }
+
+    /// Calculate the bitwise OR of `a` and `b`, and store the result in `a`.
+    ///
+    /// - Complexity: O(max(a.count, b.count))
+    public static func |= (a: inout BigUInt, b: BigUInt) {
+        a.reserveCapacity(b.count)
+        for i in 0 ..< b.count {
+            a[i] |= b[i]
+        }
+    }
+
+    /// Calculate the bitwise AND of `a` and `b` and return the result.
+    ///
+    /// - Complexity: O(max(a.count, b.count))
+    public static func &= (a: inout BigUInt, b: BigUInt) {
+        for i in 0 ..< Swift.max(a.count, b.count) {
+            a[i] &= b[i]
+        }
+    }
+
+    /// Calculate the bitwise XOR of `a` and `b` and return the result.
+    ///
+    /// - Complexity: O(max(a.count, b.count))
+    public static func ^= (a: inout BigUInt, b: BigUInt) {
+        a.reserveCapacity(b.count)
+        for i in 0 ..< b.count {
+            a[i] ^= b[i]
+        }
+    }
+}
+
+extension BigInt {
+    public static prefix func ~(x: BigInt) -> BigInt {
+        switch x.sign {
+        case .plus:
+            return BigInt(sign: .minus, magnitude: x.magnitude + 1)
+        case .minus:
+            return BigInt(sign: .plus, magnitude: x.magnitude - 1)
+        }
+    }
+    
+    public static func &(lhs: inout BigInt, rhs: BigInt) -> BigInt {
+        let left = lhs.words
+        let right = rhs.words
+        // Note we aren't using left.count/right.count here; we account for the sign bit separately later.
+        let count = Swift.max(lhs.magnitude.count, rhs.magnitude.count)
+        var words: [UInt] = []
+        words.reserveCapacity(count)
+        for i in 0 ..< count {
+            words.append(left[i] & right[i])
+        }
+        if lhs.sign == .minus && rhs.sign == .minus {
+            words.twosComplement()
+            return BigInt(sign: .minus, magnitude: BigUInt(words: words))
+        }
+        return BigInt(sign: .plus, magnitude: BigUInt(words: words))
+    }
+    
+    public static func |(lhs: inout BigInt, rhs: BigInt) -> BigInt {
+        let left = lhs.words
+        let right = rhs.words
+        // Note we aren't using left.count/right.count here; we account for the sign bit separately later.
+        let count = Swift.max(lhs.magnitude.count, rhs.magnitude.count)
+        var words: [UInt] = []
+        words.reserveCapacity(count)
+        for i in 0 ..< count {
+            words.append(left[i] | right[i])
+        }
+        if lhs.sign == .minus || rhs.sign == .minus {
+            words.twosComplement()
+            return BigInt(sign: .minus, magnitude: BigUInt(words: words))
+        }
+        return BigInt(sign: .plus, magnitude: BigUInt(words: words))
+    }
+    
+    public static func ^(lhs: inout BigInt, rhs: BigInt) -> BigInt {
+        let left = lhs.words
+        let right = rhs.words
+        // Note we aren't using left.count/right.count here; we account for the sign bit separately later.
+        let count = Swift.max(lhs.magnitude.count, rhs.magnitude.count)
+        var words: [UInt] = []
+        words.reserveCapacity(count)
+        for i in 0 ..< count {
+            words.append(left[i] ^ right[i])
+        }
+        if (lhs.sign == .minus) != (rhs.sign == .minus) {
+            words.twosComplement()
+            return BigInt(sign: .minus, magnitude: BigUInt(words: words))
+        }
+        return BigInt(sign: .plus, magnitude: BigUInt(words: words))
+    }
+    
+    public static func &=(lhs: inout BigInt, rhs: BigInt) {
+        lhs = lhs & rhs
+    }
+    
+    public static func |=(lhs: inout BigInt, rhs: BigInt) {
+        lhs = lhs | rhs
+    }
+    
+    public static func ^=(lhs: inout BigInt, rhs: BigInt) {
+        lhs = lhs ^ rhs
+    }
+}

Pods/BigInt/Sources/Codable.swift

@@ -0,0 +1,155 @@
+//
+//  Codable.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2017-8-11.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+
+// Little-endian to big-endian
+struct Units<Unit: FixedWidthInteger, Words: RandomAccessCollection>: RandomAccessCollection
+where Words.Element: FixedWidthInteger, Words.Index == Int {
+    typealias Word = Words.Element
+    let words: Words
+    init(of type: Unit.Type, _ words: Words) {
+        precondition(Word.bitWidth % Unit.bitWidth == 0 || Unit.bitWidth % Word.bitWidth == 0)
+        self.words = words
+    }
+    var count: Int { return (words.count * Word.bitWidth + Unit.bitWidth - 1) / Unit.bitWidth }
+    var startIndex: Int { return 0 }
+    var endIndex: Int { return count }
+    subscript(_ index: Int) -> Unit {
+        let index = count - 1 - index
+        if Unit.bitWidth == Word.bitWidth {
+            return Unit(words[index])
+        }
+        else if Unit.bitWidth > Word.bitWidth {
+            let c = Unit.bitWidth / Word.bitWidth
+            var unit: Unit = 0
+            var j = 0
+            for i in (c * index) ..< Swift.min(c * (index + 1), words.endIndex) {
+                unit |= Unit(words[i]) << j
+                j += Word.bitWidth
+            }
+            return unit
+        }
+        // Unit.bitWidth < Word.bitWidth
+        let c = Word.bitWidth / Unit.bitWidth
+        let i = index / c
+        let j = index % c
+        return Unit(truncatingIfNeeded: words[i] >> (j * Unit.bitWidth))
+    }
+}
+
+extension Array where Element: FixedWidthInteger {
+    // Big-endian to little-endian
+    init<Unit: FixedWidthInteger>(count: Int?, generator: () throws -> Unit?) rethrows {
+        typealias Word = Element
+        precondition(Word.bitWidth % Unit.bitWidth == 0 || Unit.bitWidth % Word.bitWidth == 0)
+        self = []
+        if Unit.bitWidth == Word.bitWidth {
+            if let count = count {
+                self.reserveCapacity(count)
+            }
+            while let unit = try generator() {
+                self.append(Word(unit))
+            }
+        }
+        else if Unit.bitWidth > Word.bitWidth {
+            let wordsPerUnit = Unit.bitWidth / Word.bitWidth
+            if let count = count {
+                self.reserveCapacity(count * wordsPerUnit)
+            }
+            while let unit = try generator() {
+                var shift = Unit.bitWidth - Word.bitWidth
+                while shift >= 0 {
+                    self.append(Word(truncatingIfNeeded: unit >> shift))
+                    shift -= Word.bitWidth
+                }
+            }
+        }
+        else {
+            let unitsPerWord = Word.bitWidth / Unit.bitWidth
+            if let count = count {
+                self.reserveCapacity((count + unitsPerWord - 1) / unitsPerWord)
+            }
+            var word: Word = 0
+            var c = 0
+            while let unit = try generator() {
+                word <<= Unit.bitWidth
+                word |= Word(unit)
+                c += Unit.bitWidth
+                if c == Word.bitWidth {
+                    self.append(word)
+                    word = 0
+                    c = 0
+                }
+            }
+            if c > 0 {
+                self.append(word << c)
+                var shifted: Word = 0
+                for i in self.indices {
+                    let word = self[i]
+                    self[i] = shifted | (word >> c)
+                    shifted = word << (Word.bitWidth - c)
+                }
+            }
+        }
+        self.reverse()
+    }
+}
+
+extension BigInt: Codable {
+    public init(from decoder: Decoder) throws {
+        var container = try decoder.unkeyedContainer()
+
+        // Decode sign
+        let sign: BigInt.Sign
+        switch try container.decode(String.self) {
+        case "+":
+            sign = .plus
+        case "-":
+            sign = .minus
+        default:
+            throw DecodingError.dataCorrupted(.init(codingPath: container.codingPath,
+                                                    debugDescription: "Invalid big integer sign"))
+        }
+
+        // Decode magnitude
+        let words = try [UInt](count: container.count?.advanced(by: -1)) { () -> UInt64? in
+            guard !container.isAtEnd else { return nil }
+            return try container.decode(UInt64.self)
+        }
+        let magnitude = BigUInt(words: words)
+
+        self.init(sign: sign, magnitude: magnitude)
+    }
+
+    public func encode(to encoder: Encoder) throws {
+        var container = encoder.unkeyedContainer()
+        try container.encode(sign == .plus ? "+" : "-")
+        let units = Units(of: UInt64.self, self.magnitude.words)
+        if units.isEmpty {
+            try container.encode(0 as UInt64)
+        }
+        else {
+            try container.encode(contentsOf: units)
+        }
+    }
+}
+
+extension BigUInt: Codable {
+    public init(from decoder: Decoder) throws {
+        let value = try BigInt(from: decoder)
+        guard value.sign == .plus else {
+            throw DecodingError.dataCorrupted(.init(codingPath: decoder.codingPath,
+                                                    debugDescription: "BigUInt cannot hold a negative value"))
+        }
+        self = value.magnitude
+    }
+
+    public func encode(to encoder: Encoder) throws {
+        try BigInt(sign: .plus, magnitude: self).encode(to: encoder)
+    }
+}

Pods/BigInt/Sources/Comparable.swift

@@ -0,0 +1,63 @@
+//
+//  Comparable.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-03.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+import Foundation
+
+extension BigUInt: Comparable {
+    //MARK: Comparison
+    
+    /// Compare `a` to `b` and return an `NSComparisonResult` indicating their order.
+    ///
+    /// - Complexity: O(count)
+    public static func compare(_ a: BigUInt, _ b: BigUInt) -> ComparisonResult {
+        if a.count != b.count { return a.count > b.count ? .orderedDescending : .orderedAscending }
+        for i in (0 ..< a.count).reversed() {
+            let ad = a[i]
+            let bd = b[i]
+            if ad != bd { return ad > bd ? .orderedDescending : .orderedAscending }
+        }
+        return .orderedSame
+    }
+
+    /// Return true iff `a` is equal to `b`.
+    ///
+    /// - Complexity: O(count)
+    public static func ==(a: BigUInt, b: BigUInt) -> Bool {
+        return BigUInt.compare(a, b) == .orderedSame
+    }
+
+    /// Return true iff `a` is less than `b`.
+    ///
+    /// - Complexity: O(count)
+    public static func <(a: BigUInt, b: BigUInt) -> Bool {
+        return BigUInt.compare(a, b) == .orderedAscending
+    }
+}
+
+extension BigInt {
+    /// Return true iff `a` is equal to `b`.
+    public static func ==(a: BigInt, b: BigInt) -> Bool {
+        return a.sign == b.sign && a.magnitude == b.magnitude
+    }
+
+    /// Return true iff `a` is less than `b`.
+    public static func <(a: BigInt, b: BigInt) -> Bool {
+        switch (a.sign, b.sign) {
+        case (.plus, .plus):
+            return a.magnitude < b.magnitude
+        case (.plus, .minus):
+            return false
+        case (.minus, .plus):
+            return true
+        case (.minus, .minus):
+            return a.magnitude > b.magnitude
+        }
+    }
+}
+
+

Pods/BigInt/Sources/Data Conversion.swift

@@ -0,0 +1,179 @@
+//
+//  Data Conversion.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-04.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+import Foundation
+
+extension BigUInt {
+    //MARK: NSData Conversion
+
+    /// Initialize a BigInt from bytes accessed from an UnsafeRawBufferPointer
+    public init(_ buffer: UnsafeRawBufferPointer) {
+        // This assumes Word is binary.
+        precondition(Word.bitWidth % 8 == 0)
+
+        self.init()
+
+        let length = buffer.count
+        guard length > 0 else { return }
+        let bytesPerDigit = Word.bitWidth / 8
+        var index = length / bytesPerDigit
+        var c = bytesPerDigit - length % bytesPerDigit
+        if c == bytesPerDigit {
+            c = 0
+            index -= 1
+        }
+
+        var word: Word = 0
+        for byte in buffer {
+            word <<= 8
+            word += Word(byte)
+            c += 1
+            if c == bytesPerDigit {
+                self[index] = word
+                index -= 1
+                c = 0
+                word = 0
+            }
+        }
+        assert(c == 0 && word == 0 && index == -1)
+    }
+
+
+    /// Initializes an integer from the bits stored inside a piece of `Data`.
+    /// The data is assumed to be in network (big-endian) byte order.
+    public init(_ data: Data) {
+        // This assumes Word is binary.
+        precondition(Word.bitWidth % 8 == 0)
+
+        self.init()
+
+        let length = data.count
+        guard length > 0 else { return }
+        let bytesPerDigit = Word.bitWidth / 8
+        var index = length / bytesPerDigit
+        var c = bytesPerDigit - length % bytesPerDigit
+        if c == bytesPerDigit {
+            c = 0
+            index -= 1
+        }
+        let word: Word = data.withUnsafeBytes { buffPtr in
+            var word: Word = 0
+            let p = buffPtr.bindMemory(to: UInt8.self)
+            for byte in p {
+                word <<= 8
+                word += Word(byte)
+                c += 1
+                if c == bytesPerDigit {
+                    self[index] = word
+                    index -= 1
+                    c = 0
+                    word = 0
+                }
+            }
+            return word
+        }
+        assert(c == 0 && word == 0 && index == -1)
+    }
+
+    /// Return a `Data` value that contains the base-256 representation of this integer, in network (big-endian) byte order.
+    public func serialize() -> Data {
+        // This assumes Digit is binary.
+        precondition(Word.bitWidth % 8 == 0)
+
+        let byteCount = (self.bitWidth + 7) / 8
+
+        guard byteCount > 0 else { return Data() }
+
+        var data = Data(count: byteCount)
+        data.withUnsafeMutableBytes { buffPtr in
+            let p = buffPtr.bindMemory(to: UInt8.self)
+            var i = byteCount - 1
+            for var word in self.words {
+                for _ in 0 ..< Word.bitWidth / 8 {
+                    p[i] = UInt8(word & 0xFF)
+                    word >>= 8
+                    if i == 0 {
+                        assert(word == 0)
+                        break
+                    }
+                    i -= 1
+                }
+            }
+        }
+        return data
+    }
+}
+
+extension BigInt {
+    
+    /// Initialize a BigInt from bytes accessed from an UnsafeRawBufferPointer,
+    /// where the first byte indicates sign (0 for positive, 1 for negative)
+    public init(_ buffer: UnsafeRawBufferPointer) {
+        // This assumes Word is binary.
+        precondition(Word.bitWidth % 8 == 0)
+        
+        self.init()
+        
+        let length = buffer.count
+        
+        // Serialized data for a BigInt should contain at least 2 bytes: one representing
+        // the sign, and another for the non-zero magnitude. Zero is represented by an
+        // empty Data struct, and negative zero is not supported.
+        guard length > 1, let firstByte = buffer.first else { return }
+
+        // The first byte gives the sign
+        // This byte is compared to a bitmask to allow additional functionality to be added
+        // to this byte in the future.
+        self.sign = firstByte & 0b1 == 0 ? .plus : .minus
+
+        self.magnitude = BigUInt(UnsafeRawBufferPointer(rebasing: buffer.dropFirst(1)))
+    }
+    
+    /// Initializes an integer from the bits stored inside a piece of `Data`.
+    /// The data is assumed to be in network (big-endian) byte order with a first
+    /// byte to represent the sign (0 for positive, 1 for negative)
+    public init(_ data: Data) {
+        // This assumes Word is binary.
+        // This is the same assumption made when initializing BigUInt from Data
+        precondition(Word.bitWidth % 8 == 0)
+
+        self.init()
+        
+        // Serialized data for a BigInt should contain at least 2 bytes: one representing
+        // the sign, and another for the non-zero magnitude. Zero is represented by an
+        // empty Data struct, and negative zero is not supported.
+        guard data.count > 1, let firstByte = data.first else { return }
+        
+        // The first byte gives the sign
+        // This byte is compared to a bitmask to allow additional functionality to be added
+        // to this byte in the future.
+        self.sign = firstByte & 0b1 == 0 ? .plus : .minus
+        
+        // The remaining bytes are read and stored as the magnitude
+        self.magnitude = BigUInt(data.dropFirst(1))
+    }
+    
+    /// Return a `Data` value that contains the base-256 representation of this integer, in network (big-endian) byte order and a prepended byte to indicate the sign (0 for positive, 1 for negative)
+    public func serialize() -> Data {
+        // Create a data object for the magnitude portion of the BigInt
+        let magnitudeData = self.magnitude.serialize()
+        
+        // Similar to BigUInt, a value of 0 should return an initialized, empty Data struct
+        guard magnitudeData.count > 0 else { return magnitudeData }
+        
+        // Create a new Data struct for the signed BigInt value
+        var data = Data(capacity: magnitudeData.count + 1)
+        
+        // The first byte should be 0 for a positive value, or 1 for a negative value
+        // i.e., the sign bit is the LSB
+        data.append(self.sign == .plus ? 0 : 1)
+        
+        data.append(magnitudeData)
+        return data
+    }
+}

Pods/BigInt/Sources/Division.swift

@@ -0,0 +1,374 @@
+//
+//  Division.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-03.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+//MARK: Full-width multiplication and division
+
+extension FixedWidthInteger where Magnitude == Self {
+    private var halfShift: Self {
+        return Self(Self.bitWidth / 2)
+
+    }
+    private var high: Self {
+        return self &>> halfShift
+    }
+
+    private var low: Self {
+        let mask: Self = 1 &<< halfShift - 1
+        return self & mask
+    }
+
+    private var upshifted: Self {
+        return self &<< halfShift
+    }
+
+    private var split: (high: Self, low: Self) {
+        return (self.high, self.low)
+    }
+
+    private init(_ value: (high: Self, low: Self)) {
+        self = value.high.upshifted + value.low
+    }
+
+    /// Divide the double-width integer `dividend` by `self` and return the quotient and remainder.
+    ///
+    /// - Requires: `dividend.high < self`, so that the result will fit in a single digit.
+    /// - Complexity: O(1) with 2 divisions, 6 multiplications and ~12 or so additions/subtractions.
+    internal func fastDividingFullWidth(_ dividend: (high: Self, low: Self.Magnitude)) -> (quotient: Self, remainder: Self) {
+        // Division is complicated; doing it with single-digit operations is maddeningly complicated.
+        // This is a Swift adaptation for "divlu2" in Hacker's Delight,
+        // which is in turn a C adaptation of Knuth's Algorithm D (TAOCP vol 2, 4.3.1).
+        precondition(dividend.high < self)
+
+        // This replaces the implementation in stdlib, which is much slower.
+        // FIXME: Speed up stdlib. It should use full-width idiv on Intel processors, and
+        // fall back to a reasonably fast algorithm elsewhere.
+
+        // The trick here is that we're actually implementing a 4/2 long division using half-words,
+        // with the long division loop unrolled into two 3/2 half-word divisions.
+        // Luckily, 3/2 half-word division can be approximated by a single full-word division operation
+        // that, when the divisor is normalized, differs from the correct result by at most 2.
+
+        /// Find the half-word quotient in `u / vn`, which must be normalized.
+        /// `u` contains three half-words in the two halves of `u.high` and the lower half of
+        /// `u.low`. (The weird distribution makes for a slightly better fit with the input.)
+        /// `vn` contains the normalized divisor, consisting of two half-words.
+        ///
+        /// - Requires: u.high < vn && u.low.high == 0 && vn.leadingZeroBitCount == 0
+        func quotient(dividing u: (high: Self, low: Self), by vn: Self) -> Self {
+            let (vn1, vn0) = vn.split
+            // Get approximate quotient.
+            let (q, r) = u.high.quotientAndRemainder(dividingBy: vn1)
+            let p = q * vn0
+            // q is often already correct, but sometimes the approximation overshoots by at most 2.
+            // The code that follows checks for this while being careful to only perform single-digit operations.
+            if q.high == 0 && p <= r.upshifted + u.low { return q }
+            let r2 = r + vn1
+            if r2.high != 0 { return q - 1 }
+            if (q - 1).high == 0 && p - vn0 <= r2.upshifted + u.low { return q - 1 }
+            //assert((r + 2 * vn1).high != 0 || p - 2 * vn0 <= (r + 2 * vn1).upshifted + u.low)
+            return q - 2
+        }
+        /// Divide 3 half-digits by 2 half-digits to get a half-digit quotient and a full-digit remainder.
+        ///
+        /// - Requires: u.high < v && u.low.high == 0 && vn.width = width(Digit)
+        func quotientAndRemainder(dividing u: (high: Self, low: Self), by v: Self) -> (quotient: Self, remainder: Self) {
+            let q = quotient(dividing: u, by: v)
+            // Note that `uh.low` masks off a couple of bits, and `q * v` and the
+            // subtraction are likely to overflow. Despite this, the end result (remainder) will
+            // still be correct and it will fit inside a single (full) Digit.
+            let r = Self(u) &- q &* v
+            assert(r < v)
+            return (q, r)
+        }
+
+        // Normalize the dividend and the divisor (self) such that the divisor has no leading zeroes.
+        let z = Self(self.leadingZeroBitCount)
+        let w = Self(Self.bitWidth) - z
+        let vn = self << z
+
+        let un32 = (z == 0 ? dividend.high : (dividend.high &<< z) | (dividend.low &>> w)) // No bits are lost
+        let un10 = dividend.low &<< z
+        let (un1, un0) = un10.split
+
+        // Divide `(un32,un10)` by `vn`, splitting the full 4/2 division into two 3/2 ones.
+        let (q1, un21) = quotientAndRemainder(dividing: (un32, un1), by: vn)
+        let (q0, rn) = quotientAndRemainder(dividing: (un21, un0), by: vn)
+
+        // Undo normalization of the remainder and combine the two halves of the quotient.
+        let mod = rn >> z
+        let div = Self((q1, q0))
+        return (div, mod)
+    }
+
+    /// Return the quotient of the 3/2-word division `x/y` as a single word.
+    ///
+    /// - Requires: (x.0, x.1) <= y && y.0.high != 0
+    /// - Returns: The exact value when it fits in a single word, otherwise `Self`.
+    static func approximateQuotient(dividing x: (Self, Self, Self), by y: (Self, Self)) -> Self {
+        // Start with q = (x.0, x.1) / y.0, (or Word.max on overflow)
+        var q: Self
+        var r: Self
+        if x.0 == y.0 {
+            q = Self.max
+            let (s, o) = x.0.addingReportingOverflow(x.1)
+            if o { return q }
+            r = s
+        }
+        else {
+            (q, r) = y.0.fastDividingFullWidth((x.0, x.1))
+        }
+        // Now refine q by considering x.2 and y.1.
+        // Note that since y is normalized, q * y - x is between 0 and 2.
+        let (ph, pl) = q.multipliedFullWidth(by: y.1)
+        if ph < r || (ph == r && pl <= x.2) { return q }
+
+        let (r1, ro) = r.addingReportingOverflow(y.0)
+        if ro { return q - 1 }
+
+        let (pl1, so) = pl.subtractingReportingOverflow(y.1)
+        let ph1 = (so ? ph - 1 : ph)
+
+        if ph1 < r1 || (ph1 == r1 && pl1 <= x.2) { return q - 1 }
+        return q - 2
+    }
+}
+
+extension BigUInt {
+    //MARK: Division
+
+    /// Divide this integer by the word `y`, leaving the quotient in its place and returning the remainder.
+    ///
+    /// - Requires: y > 0
+    /// - Complexity: O(count)
+    internal mutating func divide(byWord y: Word) -> Word {
+        precondition(y > 0)
+        if y == 1 { return 0 }
+        
+        var remainder: Word = 0
+        for i in (0 ..< count).reversed() {
+            let u = self[i]
+            (self[i], remainder) = y.fastDividingFullWidth((remainder, u))
+        }
+        return remainder
+    }
+
+    /// Divide this integer by the word `y` and return the resulting quotient and remainder.
+    ///
+    /// - Requires: y > 0
+    /// - Returns: (quotient, remainder) where quotient = floor(x/y), remainder = x - quotient * y
+    /// - Complexity: O(x.count)
+    internal func quotientAndRemainder(dividingByWord y: Word) -> (quotient: BigUInt, remainder: Word) {
+        var div = self
+        let mod = div.divide(byWord: y)
+        return (div, mod)
+    }
+
+    /// Divide `x` by `y`, putting the quotient in `x` and the remainder in `y`.
+    /// Reusing integers like this reduces the number of allocations during the calculation.
+    static func divide(_ x: inout BigUInt, by y: inout BigUInt) {
+        // This is a Swift adaptation of "divmnu" from Hacker's Delight, which is in
+        // turn a C adaptation of Knuth's Algorithm D (TAOCP vol 2, 4.3.1).
+
+        precondition(!y.isZero)
+
+        // First, let's take care of the easy cases.
+        if x < y {
+            (x, y) = (0, x)
+            return
+        }
+        if y.count == 1 {
+            // The single-word case reduces to a simpler loop.
+            y = BigUInt(x.divide(byWord: y[0]))
+            return
+        }
+
+        // In the hard cases, we will perform the long division algorithm we learned in school.
+        // It works by successively calculating the single-word quotient of the top y.count + 1
+        // words of x divided by y, replacing the top of x with the remainder, and repeating
+        // the process one word lower.
+        //
+        // The tricky part is that the algorithm needs to be able to do n+1/n word divisions,
+        // but we only have a primitive for dividing two words by a single
+        // word. (Remember that this step is also tricky when we do it on paper!)
+        //
+        // The solution is that the long division can be approximated by a single full division
+        // using just the most significant words. We can then use multiplications and
+        // subtractions to refine the approximation until we get the correct quotient word.
+        //
+        // We could do this by doing a simple 2/1 full division, but Knuth goes one step further,
+        // and implements a 3/2 division. This results in an exact approximation in the
+        // vast majority of cases, eliminating an extra subtraction over big integers.
+        //
+        // The function `approximateQuotient` above implements Knuth's 3/2 division algorithm.
+        // It requires that the divisor's most significant word is larger than
+        // Word.max / 2. This ensures that the approximation has tiny error bounds,
+        // which is what makes this entire approach viable.
+        // To satisfy this requirement, we will normalize the division by multiplying
+        // both the divisor and the dividend by the same (small) factor.
+        let z = y.leadingZeroBitCount
+        y <<= z
+        x <<= z // We'll calculate the remainder in the normalized dividend.
+        var quotient = BigUInt()
+        assert(y.leadingZeroBitCount == 0)
+
+        // We're ready to start the long division!
+        let dc = y.count
+        let d1 = y[dc - 1]
+        let d0 = y[dc - 2]
+        var product: BigUInt = 0
+        for j in (dc ... x.count).reversed() {
+            // Approximate dividing the top dc+1 words of `remainder` using the topmost 3/2 words.
+            let r2 = x[j]
+            let r1 = x[j - 1]
+            let r0 = x[j - 2]
+            let q = Word.approximateQuotient(dividing: (r2, r1, r0), by: (d1, d0))
+
+            // Multiply the entire divisor with `q` and subtract the result from remainder.
+            // Normalization ensures the 3/2 quotient will either be exact for the full division, or
+            // it may overshoot by at most 1, in which case the product will be greater
+            // than the remainder.
+            product.load(y)
+            product.multiply(byWord: q)
+            if product <= x.extract(j - dc ..< j + 1) {
+                x.subtract(product, shiftedBy: j - dc)
+                quotient[j - dc] = q
+            }
+            else {
+                // This case is extremely rare -- it has a probability of 1/2^(Word.bitWidth - 1).
+                x.add(y, shiftedBy: j - dc)
+                x.subtract(product, shiftedBy: j - dc)
+                quotient[j - dc] = q - 1
+            }
+        }
+        // The remainder's normalization needs to be undone, but otherwise we're done.
+        x >>= z
+        y = x
+        x = quotient
+    }
+
+    /// Divide `x` by `y`, putting the remainder in `x`.
+    mutating func formRemainder(dividingBy y: BigUInt, normalizedBy shift: Int) {
+        precondition(!y.isZero)
+        assert(y.leadingZeroBitCount == 0)
+        if y.count == 1 {
+            let remainder = self.divide(byWord: y[0] >> shift)
+            self.load(BigUInt(remainder))
+            return
+        }
+        self <<= shift
+        if self >= y {
+            let dc = y.count
+            let d1 = y[dc - 1]
+            let d0 = y[dc - 2]
+            var product: BigUInt = 0
+            for j in (dc ... self.count).reversed() {
+                let r2 = self[j]
+                let r1 = self[j - 1]
+                let r0 = self[j - 2]
+                let q = Word.approximateQuotient(dividing: (r2, r1, r0), by: (d1, d0))
+                product.load(y)
+                product.multiply(byWord: q)
+                if product <= self.extract(j - dc ..< j + 1) {
+                    self.subtract(product, shiftedBy: j - dc)
+                }
+                else {
+                    self.add(y, shiftedBy: j - dc)
+                    self.subtract(product, shiftedBy: j - dc)
+                }
+            }
+        }
+        self >>= shift
+    }
+
+
+    /// Divide this integer by `y` and return the resulting quotient and remainder.
+    ///
+    /// - Requires: `y > 0`
+    /// - Returns: `(quotient, remainder)` where `quotient = floor(self/y)`, `remainder = self - quotient * y`
+    /// - Complexity: O(count^2)
+    public func quotientAndRemainder(dividingBy y: BigUInt) -> (quotient: BigUInt, remainder: BigUInt) {
+        var x = self
+        var y = y
+        BigUInt.divide(&x, by: &y)
+        return (x, y)
+    }
+
+    /// Divide `x` by `y` and return the quotient.
+    ///
+    /// - Note: Use `divided(by:)` if you also need the remainder.
+    public static func /(x: BigUInt, y: BigUInt) -> BigUInt {
+        return x.quotientAndRemainder(dividingBy: y).quotient
+    }
+
+    /// Divide `x` by `y` and return the remainder.
+    ///
+    /// - Note: Use `divided(by:)` if you also need the remainder.
+    public static func %(x: BigUInt, y: BigUInt) -> BigUInt {
+        var x = x
+        let shift = y.leadingZeroBitCount
+        x.formRemainder(dividingBy: y << shift, normalizedBy: shift)
+        return x
+    }
+
+    /// Divide `x` by `y` and store the quotient in `x`.
+    ///
+    /// - Note: Use `divided(by:)` if you also need the remainder.
+    public static func /=(x: inout BigUInt, y: BigUInt) {
+        var y = y
+        BigUInt.divide(&x, by: &y)
+    }
+
+    /// Divide `x` by `y` and store the remainder in `x`.
+    ///
+    /// - Note: Use `divided(by:)` if you also need the remainder.
+    public static func %=(x: inout BigUInt, y: BigUInt) {
+        let shift = y.leadingZeroBitCount
+        x.formRemainder(dividingBy: y << shift, normalizedBy: shift)
+    }
+}
+
+extension BigInt {
+    /// Divide this integer by `y` and return the resulting quotient and remainder.
+    ///
+    /// - Requires: `y > 0`
+    /// - Returns: `(quotient, remainder)` where `quotient = floor(self/y)`, `remainder = self - quotient * y`
+    /// - Complexity: O(count^2)
+    public func quotientAndRemainder(dividingBy y: BigInt) -> (quotient: BigInt, remainder: BigInt) {
+        var a = self.magnitude
+        var b = y.magnitude
+        BigUInt.divide(&a, by: &b)
+        return (BigInt(sign: self.sign == y.sign ? .plus : .minus, magnitude: a),
+                BigInt(sign: self.sign, magnitude: b))
+    }
+
+    /// Divide `a` by `b` and return the quotient. Traps if `b` is zero.
+    public static func /(a: BigInt, b: BigInt) -> BigInt {
+        return BigInt(sign: a.sign == b.sign ? .plus : .minus, magnitude: a.magnitude / b.magnitude)
+    }
+
+    /// Divide `a` by `b` and return the remainder. The result has the same sign as `a`.
+    public static func %(a: BigInt, b: BigInt) -> BigInt {
+        return BigInt(sign: a.sign, magnitude: a.magnitude % b.magnitude)
+    }
+
+    /// Return the result of `a` mod `b`. The result is always a nonnegative integer that is less than the absolute value of `b`.
+    public func modulus(_ mod: BigInt) -> BigInt {
+        let remainder = self.magnitude % mod.magnitude
+        return BigInt(
+            self.sign == .minus && !remainder.isZero
+                ? mod.magnitude - remainder
+                : remainder)
+    }
+}
+
+extension BigInt {
+    /// Divide `a` by `b` storing the quotient in `a`.
+    public static func /=(a: inout BigInt, b: BigInt) { a = a / b }
+    /// Divide `a` by `b` storing the remainder in `a`.
+    public static func %=(a: inout BigInt, b: BigInt) { a = a % b }
+}

Pods/BigInt/Sources/Exponentiation.swift

@@ -0,0 +1,119 @@
+//
+//  Exponentiation.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-03.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension BigUInt {
+    //MARK: Exponentiation
+
+    /// Returns this integer raised to the power `exponent`.
+    ///
+    /// This function calculates the result by [successively squaring the base while halving the exponent][expsqr].
+    ///
+    /// [expsqr]: https://en.wikipedia.org/wiki/Exponentiation_by_squaring
+    ///
+    /// - Note: This function can be unreasonably expensive for large exponents, which is why `exponent` is
+    ///         a simple integer value. If you want to calculate big exponents, you'll probably need to use
+    ///         the modulo arithmetic variant.
+    /// - Returns: 1 if `exponent == 0`, otherwise `self` raised to `exponent`. (This implies that `0.power(0) == 1`.)
+    /// - SeeAlso: `BigUInt.power(_:, modulus:)`
+    /// - Complexity: O((exponent * self.count)^log2(3)) or somesuch. The result may require a large amount of memory, too.
+    public func power(_ exponent: Int) -> BigUInt {
+        if exponent == 0 { return 1 }
+        if exponent == 1 { return self }
+        if exponent < 0 {
+            precondition(!self.isZero)
+            return self == 1 ? 1 : 0
+        }
+        if self <= 1 { return self }
+        var result = BigUInt(1)
+        var b = self
+        var e = exponent
+        while e > 0 {
+            if e & 1 == 1 {
+                result *= b
+            }
+            e >>= 1
+            b *= b
+        }
+        return result
+    }
+
+    /// Returns the remainder of this integer raised to the power `exponent` in modulo arithmetic under `modulus`.
+    ///
+    /// Uses the [right-to-left binary method][rtlb].
+    ///
+    /// [rtlb]: https://en.wikipedia.org/wiki/Modular_exponentiation#Right-to-left_binary_method
+    ///
+    /// - Complexity: O(exponent.count * modulus.count^log2(3)) or somesuch
+    public func power(_ exponent: BigUInt, modulus: BigUInt) -> BigUInt {
+        precondition(!modulus.isZero)
+        if modulus == (1 as BigUInt) { return 0 }
+        let shift = modulus.leadingZeroBitCount
+        let normalizedModulus = modulus << shift
+        var result = BigUInt(1)
+        var b = self
+        b.formRemainder(dividingBy: normalizedModulus, normalizedBy: shift)
+        for var e in exponent.words {
+            for _ in 0 ..< Word.bitWidth {
+                if e & 1 == 1 {
+                    result *= b
+                    result.formRemainder(dividingBy: normalizedModulus, normalizedBy: shift)
+                }
+                e >>= 1
+                b *= b
+                b.formRemainder(dividingBy: normalizedModulus, normalizedBy: shift)
+            }
+        }
+        return result
+    }
+}
+
+extension BigInt {
+    /// Returns this integer raised to the power `exponent`.
+    ///
+    /// This function calculates the result by [successively squaring the base while halving the exponent][expsqr].
+    ///
+    /// [expsqr]: https://en.wikipedia.org/wiki/Exponentiation_by_squaring
+    ///
+    /// - Note: This function can be unreasonably expensive for large exponents, which is why `exponent` is
+    ///         a simple integer value. If you want to calculate big exponents, you'll probably need to use
+    ///         the modulo arithmetic variant.
+    /// - Returns: 1 if `exponent == 0`, otherwise `self` raised to `exponent`. (This implies that `0.power(0) == 1`.)
+    /// - SeeAlso: `BigUInt.power(_:, modulus:)`
+    /// - Complexity: O((exponent * self.count)^log2(3)) or somesuch. The result may require a large amount of memory, too.
+    public func power(_ exponent: Int) -> BigInt {
+        return BigInt(sign: self.sign == .minus && exponent & 1 != 0 ? .minus : .plus,
+                      magnitude: self.magnitude.power(exponent))
+    }
+
+    /// Returns the remainder of this integer raised to the power `exponent` in modulo arithmetic under `modulus`.
+    ///
+    /// Uses the [right-to-left binary method][rtlb].
+    ///
+    /// [rtlb]: https://en.wikipedia.org/wiki/Modular_exponentiation#Right-to-left_binary_method
+    ///
+    /// - Complexity: O(exponent.count * modulus.count^log2(3)) or somesuch
+    public func power(_ exponent: BigInt, modulus: BigInt) -> BigInt {
+        precondition(!modulus.isZero)
+        if modulus.magnitude == 1 { return 0 }
+        if exponent.isZero { return 1 }
+        if exponent == 1 { return self.modulus(modulus) }
+        if exponent < 0 {
+            precondition(!self.isZero)
+            guard magnitude == 1 else { return 0 }
+            guard sign == .minus else { return 1 }
+            guard exponent.magnitude[0] & 1 != 0 else { return 1 }
+            return BigInt(modulus.magnitude - 1)
+        }
+        let power = self.magnitude.power(exponent.magnitude,
+                                         modulus: modulus.magnitude)
+        if self.sign == .plus || exponent.magnitude[0] & 1 == 0 || power.isZero {
+            return BigInt(power)
+        }
+        return BigInt(modulus.magnitude - power)
+    }
+}

Pods/BigInt/Sources/Floating Point Conversion.swift

@@ -0,0 +1,73 @@
+//
+//  Floating Point Conversion.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2017-08-11.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension BigUInt {
+    public init?<T: BinaryFloatingPoint>(exactly source: T) {
+        guard source.isFinite else { return nil }
+        guard !source.isZero else { self = 0; return }
+        guard source.sign == .plus else { return nil }
+        let value = source.rounded(.towardZero)
+        guard value == source else { return nil }
+        assert(value.floatingPointClass == .positiveNormal)
+        assert(value.exponent >= 0)
+        let significand = value.significandBitPattern
+        self = (BigUInt(1) << value.exponent) + BigUInt(significand) >> (T.significandBitCount - Int(value.exponent))
+    }
+
+    public init<T: BinaryFloatingPoint>(_ source: T) {
+        self.init(exactly: source.rounded(.towardZero))!
+    }
+}
+
+extension BigInt {
+    public init?<T: BinaryFloatingPoint>(exactly source: T) {
+        switch source.sign{
+        case .plus:
+            guard let magnitude = BigUInt(exactly: source) else { return nil }
+            self = BigInt(sign: .plus, magnitude: magnitude)
+        case .minus:
+            guard let magnitude = BigUInt(exactly: -source) else { return nil }
+            self = BigInt(sign: .minus, magnitude: magnitude)
+        }
+    }
+
+    public init<T: BinaryFloatingPoint>(_ source: T) {
+        self.init(exactly: source.rounded(.towardZero))!
+    }
+}
+
+extension BinaryFloatingPoint where RawExponent: FixedWidthInteger, RawSignificand: FixedWidthInteger {
+    public init(_ value: BigInt) {
+        guard !value.isZero else { self = 0; return }
+        let v = value.magnitude
+        let bitWidth = v.bitWidth
+        var exponent = bitWidth - 1
+        let shift = bitWidth - Self.significandBitCount - 1
+        var significand = value.magnitude >> (shift - 1)
+        if significand[0] & 3 == 3 { // Handle rounding
+            significand >>= 1
+            significand += 1
+            if significand.trailingZeroBitCount >= Self.significandBitCount {
+                exponent += 1
+            }
+        }
+        else {
+            significand >>= 1
+        }
+        let bias = 1 << (Self.exponentBitCount - 1) - 1
+        guard exponent <= bias else { self = Self.infinity; return }
+        significand &= 1 << Self.significandBitCount - 1
+        self = Self.init(sign: value.sign == .plus ? .plus : .minus,
+                         exponentBitPattern: RawExponent(bias + exponent),
+                         significandBitPattern: RawSignificand(significand))
+    }
+
+    public init(_ value: BigUInt) {
+        self.init(BigInt(sign: .plus, magnitude: value))
+    }
+}

Pods/BigInt/Sources/GCD.swift

@@ -0,0 +1,80 @@
+//
+//  GCD.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-03.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension BigUInt {
+    //MARK: Greatest Common Divisor
+    
+    /// Returns the greatest common divisor of `self` and `b`.
+    ///
+    /// - Complexity: O(count^2) where count = max(self.count, b.count)
+    public func greatestCommonDivisor(with b: BigUInt) -> BigUInt {
+        // This is Stein's algorithm: https://en.wikipedia.org/wiki/Binary_GCD_algorithm
+        if self.isZero { return b }
+        if b.isZero { return self }
+
+        let az = self.trailingZeroBitCount
+        let bz = b.trailingZeroBitCount
+        let twos = Swift.min(az, bz)
+
+        var (x, y) = (self >> az, b >> bz)
+        if x < y { swap(&x, &y) }
+
+        while !x.isZero {
+            x >>= x.trailingZeroBitCount
+            if x < y { swap(&x, &y) }
+            x -= y
+        }
+        return y << twos
+    }
+    
+    /// Returns the [multiplicative inverse of this integer in modulo `modulus` arithmetic][inverse],
+    /// or `nil` if there is no such number.
+    /// 
+    /// [inverse]: https://en.wikipedia.org/wiki/Extended_Euclidean_algorithm#Modular_integers
+    ///
+    /// - Returns: If `gcd(self, modulus) == 1`, the value returned is an integer `a < modulus` such that `(a * self) % modulus == 1`. If `self` and `modulus` aren't coprime, the return value is `nil`.
+    /// - Requires: modulus > 1
+    /// - Complexity: O(count^3)
+    public func inverse(_ modulus: BigUInt) -> BigUInt? {
+        precondition(modulus > 1)
+        var t1 = BigInt(0)
+        var t2 = BigInt(1)
+        var r1 = modulus
+        var r2 = self
+        while !r2.isZero {
+            let quotient = r1 / r2
+            (t1, t2) = (t2, t1 - BigInt(quotient) * t2)
+            (r1, r2) = (r2, r1 - quotient * r2)
+        }
+        if r1 > 1 { return nil }
+        if t1.sign == .minus { return modulus - t1.magnitude }
+        return t1.magnitude
+    }
+}
+
+extension BigInt {
+    /// Returns the greatest common divisor of `a` and `b`.
+    ///
+    /// - Complexity: O(count^2) where count = max(a.count, b.count)
+    public func greatestCommonDivisor(with b: BigInt) -> BigInt {
+        return BigInt(self.magnitude.greatestCommonDivisor(with: b.magnitude))
+    }
+
+    /// Returns the [multiplicative inverse of this integer in modulo `modulus` arithmetic][inverse],
+    /// or `nil` if there is no such number.
+    ///
+    /// [inverse]: https://en.wikipedia.org/wiki/Extended_Euclidean_algorithm#Modular_integers
+    ///
+    /// - Returns: If `gcd(self, modulus) == 1`, the value returned is an integer `a < modulus` such that `(a * self) % modulus == 1`. If `self` and `modulus` aren't coprime, the return value is `nil`.
+    /// - Requires: modulus.magnitude > 1
+    /// - Complexity: O(count^3)
+    public func inverse(_ modulus: BigInt) -> BigInt? {
+        guard let inv = self.magnitude.inverse(modulus.magnitude) else { return nil }
+        return BigInt(self.sign == .plus || inv.isZero ? inv : modulus.magnitude - inv)
+    }
+}

Pods/BigInt/Sources/Hashable.swift

@@ -0,0 +1,26 @@
+//
+//  Hashable.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-03.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension BigUInt: Hashable {
+    //MARK: Hashing
+
+    /// Append this `BigUInt` to the specified hasher.
+    public func hash(into hasher: inout Hasher) {
+        for word in self.words {
+            hasher.combine(word)
+        }
+    }
+}
+
+extension BigInt: Hashable {
+    /// Append this `BigInt` to the specified hasher.
+    public func hash(into hasher: inout Hasher) {
+        hasher.combine(sign)
+        hasher.combine(magnitude)
+    }
+}

Pods/BigInt/Sources/Integer Conversion.swift

@@ -0,0 +1,89 @@
+//
+//  Integer Conversion.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2017-08-11.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension BigUInt {
+    public init?<T: BinaryInteger>(exactly source: T) {
+        guard source >= (0 as T) else { return nil }
+        if source.bitWidth <= 2 * Word.bitWidth {
+            var it = source.words.makeIterator()
+            self.init(low: it.next() ?? 0, high: it.next() ?? 0)
+            precondition(it.next() == nil, "Length of BinaryInteger.words is greater than its bitWidth")
+        }
+        else {
+            self.init(words: source.words)
+        }
+    }
+
+    public init<T: BinaryInteger>(_ source: T) {
+        precondition(source >= (0 as T), "BigUInt cannot represent negative values")
+        self.init(exactly: source)!
+    }
+
+    public init<T: BinaryInteger>(truncatingIfNeeded source: T) {
+        self.init(words: source.words)
+    }
+
+    public init<T: BinaryInteger>(clamping source: T) {
+        if source <= (0 as T) {
+            self.init()
+        }
+        else {
+            self.init(words: source.words)
+        }
+    }
+}
+
+extension BigInt {
+    public init() {
+        self.init(sign: .plus, magnitude: 0)
+    }
+
+    /// Initializes a new signed big integer with the same value as the specified unsigned big integer.
+    public init(_ integer: BigUInt) {
+        self.magnitude = integer
+        self.sign = .plus
+    }
+
+    public init<T>(_ source: T) where T : BinaryInteger {
+        if source >= (0 as T) {
+            self.init(sign: .plus, magnitude: BigUInt(source))
+        }
+        else {
+            var words = Array(source.words)
+            words.twosComplement()
+            self.init(sign: .minus, magnitude: BigUInt(words: words))
+        }
+    }
+
+    public init?<T>(exactly source: T) where T : BinaryInteger {
+        self.init(source)
+    }
+
+    public init<T>(clamping source: T) where T : BinaryInteger {
+        self.init(source)
+    }
+
+    public init<T>(truncatingIfNeeded source: T) where T : BinaryInteger {
+        self.init(source)
+    }
+}
+
+extension BigUInt: ExpressibleByIntegerLiteral {
+    /// Initialize a new big integer from an integer literal.
+    public init(integerLiteral value: UInt64) {
+        self.init(value)
+    }
+}
+
+extension BigInt: ExpressibleByIntegerLiteral {
+    /// Initialize a new big integer from an integer literal.
+    public init(integerLiteral value: Int64) {
+        self.init(value)
+    }
+}
+

Pods/BigInt/Sources/Multiplication.swift

@@ -0,0 +1,165 @@
+//
+//  Multiplication.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-03.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension BigUInt {
+
+    //MARK: Multiplication
+
+    /// Multiply this big integer by a single word, and store the result in place of the original big integer.
+    ///
+    /// - Complexity: O(count)
+    public mutating func multiply(byWord y: Word) {
+        guard y != 0 else { self = 0; return }
+        guard y != 1 else { return }
+        var carry: Word = 0
+        let c = self.count
+        for i in 0 ..< c {
+            let (h, l) = self[i].multipliedFullWidth(by: y)
+            let (low, o) = l.addingReportingOverflow(carry)
+            self[i] = low
+            carry = (o ? h + 1 : h)
+        }
+        self[c] = carry
+    }
+
+    /// Multiply this big integer by a single Word, and return the result.
+    ///
+    /// - Complexity: O(count)
+    public func multiplied(byWord y: Word) -> BigUInt {
+        var r = self
+        r.multiply(byWord: y)
+        return r
+    }
+
+    /// Multiply `x` by `y`, and add the result to this integer, optionally shifted `shift` words to the left.
+    ///
+    /// - Note: This is the fused multiply/shift/add operation; it is more efficient than doing the components
+    ///   individually. (The fused operation doesn't need to allocate space for temporary big integers.)
+    /// - Returns: `self` is set to `self + (x * y) << (shift * 2^Word.bitWidth)`
+    /// - Complexity: O(count)
+    public mutating func multiplyAndAdd(_ x: BigUInt, _ y: Word, shiftedBy shift: Int = 0) {
+        precondition(shift >= 0)
+        guard y != 0 && x.count > 0 else { return }
+        guard y != 1 else { self.add(x, shiftedBy: shift); return }
+        var mulCarry: Word = 0
+        var addCarry = false
+        let xc = x.count
+        var xi = 0
+        while xi < xc || addCarry || mulCarry > 0 {
+            let (h, l) = x[xi].multipliedFullWidth(by: y)
+            let (low, o) = l.addingReportingOverflow(mulCarry)
+            mulCarry = (o ? h + 1 : h)
+
+            let ai = shift + xi
+            let (sum1, so1) = self[ai].addingReportingOverflow(low)
+            if addCarry {
+                let (sum2, so2) = sum1.addingReportingOverflow(1)
+                self[ai] = sum2
+                addCarry = so1 || so2
+            }
+            else {
+                self[ai] = sum1
+                addCarry = so1
+            }
+            xi += 1
+        }
+    }
+
+    /// Multiply this integer by `y` and return the result.
+    ///
+    /// - Note: This uses the naive O(n^2) multiplication algorithm unless both arguments have more than
+    ///   `BigUInt.directMultiplicationLimit` words.
+    /// - Complexity: O(n^log2(3))
+    public func multiplied(by y: BigUInt) -> BigUInt {
+        // This method is mostly defined for symmetry with the rest of the arithmetic operations.
+        return self * y
+    }
+
+    /// Multiplication switches to an asymptotically better recursive algorithm when arguments have more words than this limit.
+    public static var directMultiplicationLimit: Int = 1024
+
+    /// Multiply `a` by `b` and return the result.
+    ///
+    /// - Note: This uses the naive O(n^2) multiplication algorithm unless both arguments have more than
+    ///   `BigUInt.directMultiplicationLimit` words.
+    /// - Complexity: O(n^log2(3))
+    public static func *(x: BigUInt, y: BigUInt) -> BigUInt {
+        let xc = x.count
+        let yc = y.count
+        if xc == 0 { return BigUInt() }
+        if yc == 0 { return BigUInt() }
+        if yc == 1 { return x.multiplied(byWord: y[0]) }
+        if xc == 1 { return y.multiplied(byWord: x[0]) }
+
+        if Swift.min(xc, yc) <= BigUInt.directMultiplicationLimit {
+            // Long multiplication.
+            let left = (xc < yc ? y : x)
+            let right = (xc < yc ? x : y)
+            var result = BigUInt()
+            for i in (0 ..< right.count).reversed() {
+                result.multiplyAndAdd(left, right[i], shiftedBy: i)
+            }
+            return result
+        }
+
+        if yc < xc {
+            let (xh, xl) = x.split
+            var r = xl * y
+            r.add(xh * y, shiftedBy: x.middleIndex)
+            return r
+        }
+        else if xc < yc {
+            let (yh, yl) = y.split
+            var r = yl * x
+            r.add(yh * x, shiftedBy: y.middleIndex)
+            return r
+        }
+
+        let shift = x.middleIndex
+
+        // Karatsuba multiplication:
+        // x * y = <a,b> * <c,d> = <ac, ac + bd - (a-b)(c-d), bd> (ignoring carry)
+        let (a, b) = x.split
+        let (c, d) = y.split
+
+        let high = a * c
+        let low = b * d
+        let xp = a >= b
+        let yp = c >= d
+        let xm = (xp ? a - b : b - a)
+        let ym = (yp ? c - d : d - c)
+        let m = xm * ym
+
+        var r = low
+        r.add(high, shiftedBy: 2 * shift)
+        r.add(low, shiftedBy: shift)
+        r.add(high, shiftedBy: shift)
+        if xp == yp {
+            r.subtract(m, shiftedBy: shift)
+        }
+        else {
+            r.add(m, shiftedBy: shift)
+        }
+        return r
+    }
+
+    /// Multiply `a` by `b` and store the result in `a`.
+    public static func *=(a: inout BigUInt, b: BigUInt) {
+        a = a * b
+    }
+}
+
+extension BigInt {
+    /// Multiply `a` with `b` and return the result.
+    public static func *(a: BigInt, b: BigInt) -> BigInt {
+        return BigInt(sign: a.sign == b.sign ? .plus : .minus, magnitude: a.magnitude * b.magnitude)
+    }
+
+    /// Multiply `a` with `b` in place.
+    public static func *=(a: inout BigInt, b: BigInt) { a = a * b }
+}

Pods/BigInt/Sources/Prime Test.swift

@@ -0,0 +1,153 @@
+//
+//  Prime Test.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-04.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+/// The first several [prime numbers][primes]. 
+///
+/// [primes]: https://oeis.org/A000040
+let primes: [BigUInt.Word] = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41]
+
+/// The ith element in this sequence is the smallest composite number that passes the strong probable prime test
+/// for all of the first (i+1) primes.
+///
+/// This is sequence [A014233](http://oeis.org/A014233) on the [Online Encyclopaedia of Integer Sequences](http://oeis.org).
+let pseudoPrimes: [BigUInt] = [
+    /*  2 */ 2_047,
+    /*  3 */ 1_373_653,
+    /*  5 */ 25_326_001,
+    /*  7 */ 3_215_031_751,
+    /* 11 */ 2_152_302_898_747,
+    /* 13 */ 3_474_749_660_383,
+    /* 17 */ 341_550_071_728_321,
+    /* 19 */ 341_550_071_728_321,
+    /* 23 */ 3_825_123_056_546_413_051,
+    /* 29 */ 3_825_123_056_546_413_051,
+    /* 31 */ 3_825_123_056_546_413_051,
+    /* 37 */ "318665857834031151167461",
+    /* 41 */ "3317044064679887385961981",
+]
+
+extension BigUInt {
+    //MARK: Primality Testing
+
+    /// Returns true iff this integer passes the [strong probable prime test][sppt] for the specified base.
+    ///
+    /// [sppt]: https://en.wikipedia.org/wiki/Probable_prime
+    public func isStrongProbablePrime(_ base: BigUInt) -> Bool {
+        precondition(base > (1 as BigUInt))
+        precondition(self > (0 as BigUInt))
+        let dec = self - 1
+
+        let r = dec.trailingZeroBitCount
+        let d = dec >> r
+
+        var test = base.power(d, modulus: self)
+        if test == 1 || test == dec { return true }
+
+        if r > 0 {
+            let shift = self.leadingZeroBitCount
+            let normalized = self << shift
+            for _ in 1 ..< r {
+                test *= test
+                test.formRemainder(dividingBy: normalized, normalizedBy: shift)
+                if test == 1 {
+                    return false
+                }
+                if test == dec { return true }
+            }
+        }
+        return false
+    }
+
+    /// Returns true if this integer is probably prime. Returns false if this integer is definitely not prime.
+    ///
+    /// This function performs a probabilistic [Miller-Rabin Primality Test][mrpt], consisting of `rounds` iterations, 
+    /// each calculating the strong probable prime test for a random base. The number of rounds is 10 by default,
+    /// but you may specify your own choice.
+    ///
+    /// To speed things up, the function checks if `self` is divisible by the first few prime numbers before
+    /// diving into (slower) Miller-Rabin testing.
+    ///
+    /// Also, when `self` is less than 82 bits wide, `isPrime` does a deterministic test that is guaranteed to 
+    /// return a correct result.
+    ///
+    /// [mrpt]: https://en.wikipedia.org/wiki/Miller–Rabin_primality_test
+    public func isPrime(rounds: Int = 10) -> Bool {
+        if count <= 1 && self[0] < 2 { return false }
+        if count == 1 && self[0] < 4 { return true }
+
+        // Even numbers above 2 aren't prime.
+        if self[0] & 1 == 0 { return false }
+
+        // Quickly check for small primes.
+        for i in 1 ..< primes.count {
+            let p = primes[i]
+            if self.count == 1 && self[0] == p {
+                return true
+            }
+            if self.quotientAndRemainder(dividingByWord: p).remainder == 0 {
+                return false
+            }
+        }
+
+        /// Give an exact answer when we can.
+        if self < pseudoPrimes.last! {
+            for i in 0 ..< pseudoPrimes.count {
+                guard isStrongProbablePrime(BigUInt(primes[i])) else {
+                    break
+                }
+                if self < pseudoPrimes[i] {
+                    // `self` is below the lowest pseudoprime corresponding to the prime bases we tested. It's a prime!
+                    return true
+                }
+            }
+            return false
+        }
+
+        /// Otherwise do as many rounds of random SPPT as required.
+        for _ in 0 ..< rounds {
+            let random = BigUInt.randomInteger(lessThan: self - 2) + 2
+            guard isStrongProbablePrime(random) else {
+                return false
+            }
+        }
+
+        // Well, it smells primey to me.
+        return true
+    }
+}
+
+extension BigInt {
+    //MARK: Primality Testing
+
+    /// Returns true iff this integer passes the [strong probable prime test][sppt] for the specified base.
+    ///
+    /// [sppt]: https://en.wikipedia.org/wiki/Probable_prime
+    public func isStrongProbablePrime(_ base: BigInt) -> Bool {
+        precondition(base.sign == .plus)
+        if self.sign == .minus { return false }
+        return self.magnitude.isStrongProbablePrime(base.magnitude)
+    }
+
+    /// Returns true if this integer is probably prime. Returns false if this integer is definitely not prime.
+    ///
+    /// This function performs a probabilistic [Miller-Rabin Primality Test][mrpt], consisting of `rounds` iterations,
+    /// each calculating the strong probable prime test for a random base. The number of rounds is 10 by default,
+    /// but you may specify your own choice.
+    ///
+    /// To speed things up, the function checks if `self` is divisible by the first few prime numbers before
+    /// diving into (slower) Miller-Rabin testing.
+    ///
+    /// Also, when `self` is less than 82 bits wide, `isPrime` does a deterministic test that is guaranteed to
+    /// return a correct result.
+    ///
+    /// [mrpt]: https://en.wikipedia.org/wiki/Miller–Rabin_primality_test
+    public func isPrime(rounds: Int = 10) -> Bool {
+        if self.sign == .minus { return false }
+        return self.magnitude.isPrime(rounds: rounds)
+    }
+}

Pods/BigInt/Sources/Random.swift

@@ -0,0 +1,101 @@
+//
+//  Random.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-04.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension BigUInt {
+    /// Create a big unsigned integer consisting of `width` uniformly distributed random bits.
+    ///
+    /// - Parameter width: The maximum number of one bits in the result.
+    /// - Parameter generator: The source of randomness.
+    /// - Returns: A big unsigned integer less than `1 << width`.
+    public static func randomInteger<RNG: RandomNumberGenerator>(withMaximumWidth width: Int, using generator: inout RNG) -> BigUInt {
+        var result = BigUInt.zero
+        var bitsLeft = width
+        var i = 0
+        let wordsNeeded = (width + Word.bitWidth - 1) / Word.bitWidth
+        if wordsNeeded > 2 {
+            result.reserveCapacity(wordsNeeded)
+        }
+        while bitsLeft >= Word.bitWidth {
+            result[i] = generator.next()
+            i += 1
+            bitsLeft -= Word.bitWidth
+        }
+        if bitsLeft > 0 {
+            let mask: Word = (1 << bitsLeft) - 1
+            result[i] = (generator.next() as Word) & mask
+        }
+        return result
+    }
+
+    /// Create a big unsigned integer consisting of `width` uniformly distributed random bits.
+    ///
+    /// - Note: I use a `SystemRandomGeneratorGenerator` as the source of randomness.
+    ///
+    /// - Parameter width: The maximum number of one bits in the result.
+    /// - Returns: A big unsigned integer less than `1 << width`.
+    public static func randomInteger(withMaximumWidth width: Int) -> BigUInt {
+        var rng = SystemRandomNumberGenerator()
+        return randomInteger(withMaximumWidth: width, using: &rng)
+    }
+
+    /// Create a big unsigned integer consisting of `width-1` uniformly distributed random bits followed by a one bit.
+    ///
+    /// - Note: If `width` is zero, the result is zero.
+    ///
+    /// - Parameter width: The number of bits required to represent the answer.
+    /// - Parameter generator: The source of randomness.
+    /// - Returns: A random big unsigned integer whose width is `width`.
+    public static func randomInteger<RNG: RandomNumberGenerator>(withExactWidth width: Int, using generator: inout RNG) -> BigUInt {
+        // width == 0 -> return 0 because there is no room for a one bit.
+        // width == 1 -> return 1 because there is no room for any random bits.
+        guard width > 1 else { return BigUInt(width) }
+        var result = randomInteger(withMaximumWidth: width - 1, using: &generator)
+        result[(width - 1) / Word.bitWidth] |= 1 << Word((width - 1) % Word.bitWidth)
+        return result
+    }
+
+    /// Create a big unsigned integer consisting of `width-1` uniformly distributed random bits followed by a one bit.
+    ///
+    /// - Note: If `width` is zero, the result is zero.
+    /// - Note: I use a `SystemRandomGeneratorGenerator` as the source of randomness.
+    ///
+    /// - Returns: A random big unsigned integer whose width is `width`.
+    public static func randomInteger(withExactWidth width: Int) -> BigUInt {
+        var rng = SystemRandomNumberGenerator()
+        return randomInteger(withExactWidth: width, using: &rng)
+    }
+
+    /// Create a uniformly distributed random unsigned integer that's less than the specified limit.
+    ///
+    /// - Precondition: `limit > 0`.
+    ///
+    /// - Parameter limit: The upper bound on the result.
+    /// - Parameter generator: The source of randomness.
+    /// - Returns: A random big unsigned integer that is less than `limit`.
+    public static func randomInteger<RNG: RandomNumberGenerator>(lessThan limit: BigUInt, using generator: inout RNG) -> BigUInt {
+        precondition(limit > 0, "\(#function): 0 is not a valid limit")
+        let width = limit.bitWidth
+        var random = randomInteger(withMaximumWidth: width, using: &generator)
+        while random >= limit {
+            random = randomInteger(withMaximumWidth: width, using: &generator)
+        }
+        return random
+    }
+
+    /// Create a uniformly distributed random unsigned integer that's less than the specified limit.
+    ///
+    /// - Precondition: `limit > 0`.
+    /// - Note: I use a `SystemRandomGeneratorGenerator` as the source of randomness.
+    ///
+    /// - Parameter limit: The upper bound on the result.
+    /// - Returns: A random big unsigned integer that is less than `limit`.
+    public static func randomInteger(lessThan limit: BigUInt) -> BigUInt {
+        var rng = SystemRandomNumberGenerator()
+        return randomInteger(lessThan: limit, using: &rng)
+    }
+}

Pods/BigInt/Sources/Shifts.swift

@@ -0,0 +1,211 @@
+//
+//  Shifts.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-03.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension BigUInt {
+
+    //MARK: Shift Operators
+    
+    internal func shiftedLeft(by amount: Word) -> BigUInt {
+        guard amount > 0 else { return self }
+        
+        let ext = Int(amount / Word(Word.bitWidth)) // External shift amount (new words)
+        let up = Word(amount % Word(Word.bitWidth)) // Internal shift amount (subword shift)
+        let down = Word(Word.bitWidth) - up
+        
+        var result = BigUInt()
+        if up > 0 {
+            var i = 0
+            var lowbits: Word = 0
+            while i < self.count || lowbits > 0 {
+                let word = self[i]
+                result[i + ext] = word << up | lowbits
+                lowbits = word >> down
+                i += 1
+            }
+        }
+        else {
+            for i in 0 ..< self.count {
+                result[i + ext] = self[i]
+            }
+        }
+        return result
+    }
+    
+    internal mutating func shiftLeft(by amount: Word) {
+        guard amount > 0 else { return }
+        
+        let ext = Int(amount / Word(Word.bitWidth)) // External shift amount (new words)
+        let up = Word(amount % Word(Word.bitWidth)) // Internal shift amount (subword shift)
+        let down = Word(Word.bitWidth) - up
+        
+        if up > 0 {
+            var i = 0
+            var lowbits: Word = 0
+            while i < self.count || lowbits > 0 {
+                let word = self[i]
+                self[i] = word << up | lowbits
+                lowbits = word >> down
+                i += 1
+            }
+        }
+        if ext > 0 && self.count > 0 {
+            self.shiftLeft(byWords: ext)
+        }
+    }
+    
+    internal func shiftedRight(by amount: Word) -> BigUInt {
+        guard amount > 0 else { return self }
+        guard amount < self.bitWidth else { return 0 }
+        
+        let ext = Int(amount / Word(Word.bitWidth)) // External shift amount (new words)
+        let down = Word(amount % Word(Word.bitWidth)) // Internal shift amount (subword shift)
+        let up = Word(Word.bitWidth) - down
+        
+        var result = BigUInt()
+        if down > 0 {
+            var highbits: Word = 0
+            for i in (ext ..< self.count).reversed() {
+                let word = self[i]
+                result[i - ext] = highbits | word >> down
+                highbits = word << up
+            }
+        }
+        else {
+            for i in (ext ..< self.count).reversed() {
+                result[i - ext] = self[i]
+            }
+        }
+        return result
+    }
+
+    internal mutating func shiftRight(by amount: Word) {
+        guard amount > 0 else { return }
+        guard amount < self.bitWidth else { self.clear(); return }
+        
+        let ext = Int(amount / Word(Word.bitWidth)) // External shift amount (new words)
+        let down = Word(amount % Word(Word.bitWidth)) // Internal shift amount (subword shift)
+        let up = Word(Word.bitWidth) - down
+        
+        if ext > 0 {
+            self.shiftRight(byWords: ext)
+        }
+        if down > 0 {
+            var i = self.count - 1
+            var highbits: Word = 0
+            while i >= 0 {
+                let word = self[i]
+                self[i] = highbits | word >> down
+                highbits = word << up
+                i -= 1
+            }
+        }
+    }
+    
+    public static func >>=<Other: BinaryInteger>(lhs: inout BigUInt, rhs: Other) {
+        if rhs < (0 as Other) {
+            lhs <<= (0 - rhs)
+        }
+        else if rhs >= lhs.bitWidth {
+            lhs.clear()
+        }
+        else {
+            lhs.shiftRight(by: UInt(rhs))
+        }
+    }
+    
+    public static func <<=<Other: BinaryInteger>(lhs: inout BigUInt, rhs: Other) {
+        if rhs < (0 as Other) {
+            lhs >>= (0 - rhs)
+            return
+        }
+        lhs.shiftLeft(by: Word(exactly: rhs)!)
+    }
+
+    public static func >><Other: BinaryInteger>(lhs: BigUInt, rhs: Other) -> BigUInt {
+        if rhs < (0 as Other) {
+            return lhs << (0 - rhs)
+        }
+        if rhs > Word.max {
+            return 0
+        }
+        return lhs.shiftedRight(by: UInt(rhs))
+    }
+
+    public static func <<<Other: BinaryInteger>(lhs: BigUInt, rhs: Other) -> BigUInt {
+        if rhs < (0 as Other) {
+            return lhs >> (0 - rhs)
+        }
+        return lhs.shiftedLeft(by: Word(exactly: rhs)!)
+    }
+}
+
+extension BigInt {
+    func shiftedLeft(by amount: Word) -> BigInt {
+        return BigInt(sign: self.sign, magnitude: self.magnitude.shiftedLeft(by: amount))
+    }
+    
+    mutating func shiftLeft(by amount: Word) {
+        self.magnitude.shiftLeft(by: amount)
+    }
+    
+    func shiftedRight(by amount: Word) -> BigInt {
+        let m = self.magnitude.shiftedRight(by: amount)
+        return BigInt(sign: self.sign, magnitude: self.sign == .minus && m.isZero ? 1 : m)
+    }
+    
+    mutating func shiftRight(by amount: Word) {
+        magnitude.shiftRight(by: amount)
+        if sign == .minus, magnitude.isZero {
+            magnitude.load(1)
+        }
+    }
+    
+    public static func &<<(left: BigInt, right: BigInt) -> BigInt {
+        return left.shiftedLeft(by: right.words[0])
+    }
+    
+    public static func &<<=(left: inout BigInt, right: BigInt) {
+        left.shiftLeft(by: right.words[0])
+    }
+    
+    public static func &>>(left: BigInt, right: BigInt) -> BigInt {
+        return left.shiftedRight(by: right.words[0])
+    }
+    
+    public static func &>>=(left: inout BigInt, right: BigInt) {
+        left.shiftRight(by: right.words[0])
+    }
+    
+    public static func <<<Other: BinaryInteger>(lhs: BigInt, rhs: Other) -> BigInt {
+        guard rhs >= (0 as Other) else { return lhs >> (0 - rhs) }
+        return lhs.shiftedLeft(by: Word(rhs))
+    }
+    
+    public static func <<=<Other: BinaryInteger>(lhs: inout BigInt, rhs: Other) {
+        if rhs < (0 as Other) {
+            lhs >>= (0 - rhs)
+        }
+        else {
+            lhs.shiftLeft(by: Word(rhs))
+        }
+    }
+    
+    public static func >><Other: BinaryInteger>(lhs: BigInt, rhs: Other) -> BigInt {
+        guard rhs >= (0 as Other) else { return lhs << (0 - rhs) }
+        return lhs.shiftedRight(by: Word(rhs))
+    }
+    
+    public static func >>=<Other: BinaryInteger>(lhs: inout BigInt, rhs: Other) {
+        if rhs < (0 as Other) {
+            lhs <<= (0 - rhs)
+        }
+        else {
+            lhs.shiftRight(by: Word(rhs))
+        }
+    }
+}

Pods/BigInt/Sources/Square Root.swift

@@ -0,0 +1,41 @@
+//
+//  Square Root.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-03.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+//MARK: Square Root
+
+extension BigUInt {
+    /// Returns the integer square root of a big integer; i.e., the largest integer whose square isn't greater than `value`.
+    ///
+    /// - Returns: floor(sqrt(self))
+    public func squareRoot() -> BigUInt {
+        // This implementation uses Newton's method.
+        guard !self.isZero else { return BigUInt() }
+        var x = BigUInt(1) << ((self.bitWidth + 1) / 2)
+        var y: BigUInt = 0
+        while true {
+            y.load(self)
+            y /= x
+            y += x
+            y >>= 1
+            if x == y || x == y - 1 { break }
+            x = y
+        }
+        return x
+    }
+}
+
+extension BigInt {
+    /// Returns the integer square root of a big integer; i.e., the largest integer whose square isn't greater than `value`.
+    ///
+    /// - Requires: self >= 0
+    /// - Returns: floor(sqrt(self))
+    public func squareRoot() -> BigInt {
+        precondition(self.sign == .plus)
+        return BigInt(sign: .plus, magnitude: self.magnitude.squareRoot())
+    }
+}

Pods/BigInt/Sources/Strideable.swift

@@ -0,0 +1,38 @@
+//
+//  Strideable.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2017-08-11.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension BigUInt: Strideable {
+    /// A type that can represent the distance between two values ofa `BigUInt`.
+    public typealias Stride = BigInt
+
+    /// Adds `n` to `self` and returns the result. Traps if the result would be less than zero.
+    public func advanced(by n: BigInt) -> BigUInt {
+        return n.sign == .minus ? self - n.magnitude : self + n.magnitude
+    }
+
+    /// Returns the (potentially negative) difference between `self` and `other` as a `BigInt`. Never traps.
+    public func distance(to other: BigUInt) -> BigInt {
+        return BigInt(other) - BigInt(self)
+    }
+}
+
+extension BigInt: Strideable {
+    public typealias Stride = BigInt
+
+    /// Returns `self + n`.
+    public func advanced(by n: Stride) -> BigInt {
+        return self + n
+    }
+
+    /// Returns `other - self`.
+    public func distance(to other: BigInt) -> Stride {
+        return other - self
+    }
+}
+
+

Pods/BigInt/Sources/String Conversion.swift

@@ -0,0 +1,236 @@
+//
+//  String Conversion.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-03.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension BigUInt {
+
+    //MARK: String Conversion
+
+    /// Calculates the number of numerals in a given radix that fit inside a single `Word`.
+    ///
+    /// - Returns: (chars, power) where `chars` is highest that satisfy `radix^chars <= 2^Word.bitWidth`. `power` is zero
+    ///   if radix is a power of two; otherwise `power == radix^chars`.
+    fileprivate static func charsPerWord(forRadix radix: Int) -> (chars: Int, power: Word) {
+        var power: Word = 1
+        var overflow = false
+        var count = 0
+        while !overflow {
+            let (p, o) = power.multipliedReportingOverflow(by: Word(radix))
+            overflow = o
+            if !o || p == 0 {
+                count += 1
+                power = p
+            }
+        }
+        return (count, power)
+    }
+
+    /// Initialize a big integer from an ASCII representation in a given radix. Numerals above `9` are represented by
+    /// letters from the English alphabet.
+    ///
+    /// - Requires: `radix > 1 && radix < 36`
+    /// - Parameter `text`: A string consisting of characters corresponding to numerals in the given radix. (0-9, a-z, A-Z)
+    /// - Parameter `radix`: The base of the number system to use, or 10 if unspecified.
+    /// - Returns: The integer represented by `text`, or nil if `text` contains a character that does not represent a numeral in `radix`.
+    public init?<S: StringProtocol>(_ text: S, radix: Int = 10) {
+        precondition(radix > 1)
+        let (charsPerWord, power) = BigUInt.charsPerWord(forRadix: radix)
+
+        var words: [Word] = []
+        var end = text.endIndex
+        var start = end
+        var count = 0
+        while start != text.startIndex {
+            start = text.index(before: start)
+            count += 1
+            if count == charsPerWord {
+                guard let d = Word.init(text[start ..< end], radix: radix) else { return nil }
+                words.append(d)
+                end = start
+                count = 0
+            }
+        }
+        if start != end {
+            guard let d = Word.init(text[start ..< end], radix: radix) else { return nil }
+            words.append(d)
+        }
+
+        if power == 0 {
+            self.init(words: words)
+        }
+        else {
+            self.init()
+            for d in words.reversed() {
+                self.multiply(byWord: power)
+                self.addWord(d)
+            }
+        }
+    }
+}
+
+extension BigInt {
+    /// Initialize a big integer from an ASCII representation in a given radix. Numerals above `9` are represented by
+    /// letters from the English alphabet.
+    ///
+    /// - Requires: `radix > 1 && radix < 36`
+    /// - Parameter `text`: A string optionally starting with "-" or "+" followed by characters corresponding to numerals in the given radix. (0-9, a-z, A-Z)
+    /// - Parameter `radix`: The base of the number system to use, or 10 if unspecified.
+    /// - Returns: The integer represented by `text`, or nil if `text` contains a character that does not represent a numeral in `radix`.
+    public init?<S: StringProtocol>(_ text: S, radix: Int = 10) {
+        var magnitude: BigUInt?
+        var sign: Sign = .plus
+        if text.first == "-" {
+            sign = .minus
+            let text = text.dropFirst()
+            magnitude = BigUInt(text, radix: radix)
+        }
+        else if text.first == "+" {
+            let text = text.dropFirst()
+            magnitude = BigUInt(text, radix: radix)
+        }
+        else {
+            magnitude = BigUInt(text, radix: radix)
+        }
+        guard let m = magnitude else { return nil }
+        self.magnitude = m
+        self.sign = sign
+    }
+}
+
+extension String {
+    /// Initialize a new string with the base-10 representation of an unsigned big integer.
+    ///
+    /// - Complexity: O(v.count^2)
+    public init(_ v: BigUInt) { self.init(v, radix: 10, uppercase: false) }
+
+    /// Initialize a new string representing an unsigned big integer in the given radix (base).
+    ///
+    /// Numerals greater than 9 are represented as letters from the English alphabet,
+    /// starting with `a` if `uppercase` is false or `A` otherwise.
+    ///
+    /// - Requires: radix > 1 && radix <= 36
+    /// - Complexity: O(count) when radix is a power of two; otherwise O(count^2).
+    public init(_ v: BigUInt, radix: Int, uppercase: Bool = false) {
+        precondition(radix > 1)
+        let (charsPerWord, power) = BigUInt.charsPerWord(forRadix: radix)
+
+        guard !v.isZero else { self = "0"; return }
+
+        var parts: [String]
+        if power == 0 {
+            parts = v.words.map { String($0, radix: radix, uppercase: uppercase) }
+        }
+        else {
+            parts = []
+            var rest = v
+            while !rest.isZero {
+                let mod = rest.divide(byWord: power)
+                parts.append(String(mod, radix: radix, uppercase: uppercase))
+            }
+        }
+        assert(!parts.isEmpty)
+
+        self = ""
+        var first = true
+        for part in parts.reversed() {
+            let zeroes = charsPerWord - part.count
+            assert(zeroes >= 0)
+            if !first && zeroes > 0 {
+                // Insert leading zeroes for mid-Words
+                self += String(repeating: "0", count: zeroes)
+            }
+            first = false
+            self += part
+        }
+    }
+
+    /// Initialize a new string representing a signed big integer in the given radix (base).
+    ///
+    /// Numerals greater than 9 are represented as letters from the English alphabet,
+    /// starting with `a` if `uppercase` is false or `A` otherwise.
+    ///
+    /// - Requires: radix > 1 && radix <= 36
+    /// - Complexity: O(count) when radix is a power of two; otherwise O(count^2).
+    public init(_ value: BigInt, radix: Int = 10, uppercase: Bool = false) {
+        self = String(value.magnitude, radix: radix, uppercase: uppercase)
+        if value.sign == .minus {
+            self = "-" + self
+        }
+    }
+}
+
+extension BigUInt: ExpressibleByStringLiteral {
+    /// Initialize a new big integer from a Unicode scalar.
+    /// The scalar must represent a decimal digit.
+    public init(unicodeScalarLiteral value: UnicodeScalar) {
+        self = BigUInt(String(value), radix: 10)!
+    }
+
+    /// Initialize a new big integer from an extended grapheme cluster.
+    /// The cluster must consist of a decimal digit.
+    public init(extendedGraphemeClusterLiteral value: String) {
+        self = BigUInt(value, radix: 10)!
+    }
+
+    /// Initialize a new big integer from a decimal number represented by a string literal of arbitrary length.
+    /// The string must contain only decimal digits.
+    public init(stringLiteral value: StringLiteralType) {
+        self = BigUInt(value, radix: 10)!
+    }
+}
+
+extension BigInt: ExpressibleByStringLiteral {
+    /// Initialize a new big integer from a Unicode scalar.
+    /// The scalar must represent a decimal digit.
+    public init(unicodeScalarLiteral value: UnicodeScalar) {
+        self = BigInt(String(value), radix: 10)!
+    }
+
+    /// Initialize a new big integer from an extended grapheme cluster.
+    /// The cluster must consist of a decimal digit.
+    public init(extendedGraphemeClusterLiteral value: String) {
+        self = BigInt(value, radix: 10)!
+    }
+
+    /// Initialize a new big integer from a decimal number represented by a string literal of arbitrary length.
+    /// The string must contain only decimal digits.
+    public init(stringLiteral value: StringLiteralType) {
+        self = BigInt(value, radix: 10)!
+    }
+}
+
+extension BigUInt: CustomStringConvertible {
+    /// Return the decimal representation of this integer.
+    public var description: String {
+        return String(self, radix: 10)
+    }
+}
+
+extension BigInt: CustomStringConvertible {
+    /// Return the decimal representation of this integer.
+    public var description: String {
+        return String(self, radix: 10)
+    }
+}
+
+extension BigUInt: CustomPlaygroundDisplayConvertible {
+
+    /// Return the playground quick look representation of this integer.
+    public var playgroundDescription: Any {
+        let text = String(self)
+        return text + " (\(self.bitWidth) bits)"
+    }
+}
+
+extension BigInt: CustomPlaygroundDisplayConvertible {
+
+    /// Return the playground quick look representation of this integer.
+    public var playgroundDescription: Any {
+        let text = String(self)
+        return text + " (\(self.magnitude.bitWidth) bits)"
+    }
+}

Pods/BigInt/Sources/Subtraction.swift

@@ -0,0 +1,169 @@
+//
+//  Subtraction.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2016-01-03.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension BigUInt {
+    //MARK: Subtraction
+
+    /// Subtract `word` from this integer in place, returning a flag indicating if the operation
+    /// caused an arithmetic overflow. `word` is shifted `shift` words to the left before being subtracted.
+    ///
+    /// - Note: If the result indicates an overflow, then `self` becomes the two's complement of the absolute difference.
+    /// - Complexity: O(count)
+    internal mutating func subtractWordReportingOverflow(_ word: Word, shiftedBy shift: Int = 0) -> Bool {
+        precondition(shift >= 0)
+        var carry: Word = word
+        var i = shift
+        let count = self.count
+        while carry > 0 && i < count {
+            let (d, c) = self[i].subtractingReportingOverflow(carry)
+            self[i] = d
+            carry = (c ? 1 : 0)
+            i += 1
+        }
+        return carry > 0
+    }
+
+    /// Subtract `word` from this integer, returning the difference and a flag that is true if the operation
+    /// caused an arithmetic overflow. `word` is shifted `shift` words to the left before being subtracted.
+    ///
+    /// - Note: If `overflow` is true, then the returned value is the two's complement of the absolute difference.
+    /// - Complexity: O(count)
+    internal func subtractingWordReportingOverflow(_ word: Word, shiftedBy shift: Int = 0) -> (partialValue: BigUInt, overflow: Bool) {
+        var result = self
+        let overflow = result.subtractWordReportingOverflow(word, shiftedBy: shift)
+        return (result, overflow)
+    }
+
+    /// Subtract a digit `d` from this integer in place.
+    /// `d` is shifted `shift` digits to the left before being subtracted.
+    ///
+    /// - Requires: self >= d * 2^shift
+    /// - Complexity: O(count)
+    internal mutating func subtractWord(_ word: Word, shiftedBy shift: Int = 0) {
+        let overflow = subtractWordReportingOverflow(word, shiftedBy: shift)
+        precondition(!overflow)
+    }
+
+    /// Subtract a digit `d` from this integer and return the result.
+    /// `d` is shifted `shift` digits to the left before being subtracted.
+    ///
+    /// - Requires: self >= d * 2^shift
+    /// - Complexity: O(count)
+    internal func subtractingWord(_ word: Word, shiftedBy shift: Int = 0) -> BigUInt {
+        var result = self
+        result.subtractWord(word, shiftedBy: shift)
+        return result
+    }
+
+    /// Subtract `other` from this integer in place, and return a flag indicating if the operation caused an
+    /// arithmetic overflow. `other` is shifted `shift` digits to the left before being subtracted.
+    ///
+    /// - Note: If the result indicates an overflow, then `self` becomes the twos' complement of the absolute difference.
+    /// - Complexity: O(count)
+    public mutating func subtractReportingOverflow(_ b: BigUInt, shiftedBy shift: Int = 0) -> Bool {
+        precondition(shift >= 0)
+        var carry = false
+        var bi = 0
+        let bc = b.count
+        let count = self.count
+        while bi < bc || (shift + bi < count && carry) {
+            let ai = shift + bi
+            let (d, c) = self[ai].subtractingReportingOverflow(b[bi])
+            if carry {
+                let (d2, c2) = d.subtractingReportingOverflow(1)
+                self[ai] = d2
+                carry = c || c2
+            }
+            else {
+                self[ai] = d
+                carry = c
+            }
+            bi += 1
+        }
+        return carry
+    }
+
+    /// Subtract `other` from this integer, returning the difference and a flag indicating arithmetic overflow.
+    /// `other` is shifted `shift` digits to the left before being subtracted.
+    ///
+    /// - Note: If `overflow` is true, then the result value is the twos' complement of the absolute value of the difference.
+    /// - Complexity: O(count)
+    public func subtractingReportingOverflow(_ other: BigUInt, shiftedBy shift: Int) -> (partialValue: BigUInt, overflow: Bool) {
+        var result = self
+        let overflow = result.subtractReportingOverflow(other, shiftedBy: shift)
+        return (result, overflow)
+    }
+    
+    /// Subtracts `other` from `self`, returning the result and a flag indicating arithmetic overflow.
+    ///
+    /// - Note: When the operation overflows, then `partialValue` is the twos' complement of the absolute value of the difference.
+    /// - Complexity: O(count)
+    public func subtractingReportingOverflow(_ other: BigUInt) -> (partialValue: BigUInt, overflow: Bool) {
+        return self.subtractingReportingOverflow(other, shiftedBy: 0)
+    }
+    
+    /// Subtract `other` from this integer in place.
+    /// `other` is shifted `shift` digits to the left before being subtracted.
+    ///
+    /// - Requires: self >= other * 2^shift
+    /// - Complexity: O(count)
+    public mutating func subtract(_ other: BigUInt, shiftedBy shift: Int = 0) {
+        let overflow = subtractReportingOverflow(other, shiftedBy: shift)
+        precondition(!overflow)
+    }
+
+    /// Subtract `b` from this integer, and return the difference.
+    /// `b` is shifted `shift` digits to the left before being subtracted.
+    ///
+    /// - Requires: self >= b * 2^shift
+    /// - Complexity: O(count)
+    public func subtracting(_ other: BigUInt, shiftedBy shift: Int = 0) -> BigUInt {
+        var result = self
+        result.subtract(other, shiftedBy: shift)
+        return result
+    }
+
+    /// Decrement this integer by one.
+    ///
+    /// - Requires: !isZero
+    /// - Complexity: O(count)
+    public mutating func decrement(shiftedBy shift: Int = 0) {
+        self.subtract(1, shiftedBy: shift)
+    }
+
+    /// Subtract `b` from `a` and return the result.
+    ///
+    /// - Requires: a >= b
+    /// - Complexity: O(a.count)
+    public static func -(a: BigUInt, b: BigUInt) -> BigUInt {
+        return a.subtracting(b)
+    }
+
+    /// Subtract `b` from `a` and store the result in `a`.
+    ///
+    /// - Requires: a >= b
+    /// - Complexity: O(a.count)
+    public static func -=(a: inout BigUInt, b: BigUInt) {
+        a.subtract(b)
+    }
+}
+
+extension BigInt {
+    public mutating func negate() {
+        guard !magnitude.isZero else { return }
+        self.sign = self.sign == .plus ? .minus : .plus
+    }
+
+    /// Subtract `b` from `a` and return the result.
+    public static func -(a: BigInt, b: BigInt) -> BigInt {
+        return a + -b
+    }
+
+    /// Subtract `b` from `a` in place.
+    public static func -=(a: inout BigInt, b: BigInt) { a = a - b }
+}

Pods/BigInt/Sources/Words and Bits.swift

@@ -0,0 +1,202 @@
+//
+//  Words and Bits.swift
+//  BigInt
+//
+//  Created by Károly Lőrentey on 2017-08-11.
+//  Copyright © 2016-2017 Károly Lőrentey.
+//
+
+extension Array where Element == UInt {
+    mutating func twosComplement() {
+        var increment = true
+        for i in 0 ..< self.count {
+            if increment {
+                (self[i], increment) = (~self[i]).addingReportingOverflow(1)
+            }
+            else {
+                self[i] = ~self[i]
+            }
+        }
+    }
+}
+
+extension BigUInt {
+    public subscript(bitAt index: Int) -> Bool {
+        get {
+            precondition(index >= 0)
+            let (i, j) = index.quotientAndRemainder(dividingBy: Word.bitWidth)
+            return self[i] & (1 << j) != 0
+        }
+        set {
+            precondition(index >= 0)
+            let (i, j) = index.quotientAndRemainder(dividingBy: Word.bitWidth)
+            if newValue {
+                self[i] |= 1 << j
+            }
+            else {
+                self[i] &= ~(1 << j)
+            }
+        }
+    }
+}
+
+extension BigUInt {
+    /// The minimum number of bits required to represent this integer in binary.
+    ///
+    /// - Returns: floor(log2(2 * self + 1))
+    /// - Complexity: O(1)
+    public var bitWidth: Int {
+        guard count > 0 else { return 0 }
+        return count * Word.bitWidth - self[count - 1].leadingZeroBitCount
+    }
+
+    /// The number of leading zero bits in the binary representation of this integer in base `2^(Word.bitWidth)`.
+    /// This is useful when you need to normalize a `BigUInt` such that the top bit of its most significant word is 1.
+    ///
+    /// - Note: 0 is considered to have zero leading zero bits.
+    /// - Returns: A value in `0...(Word.bitWidth - 1)`.
+    /// - SeeAlso: width
+    /// - Complexity: O(1)
+    public var leadingZeroBitCount: Int {
+        guard count > 0 else { return 0 }
+        return self[count - 1].leadingZeroBitCount
+    }
+
+    /// The number of trailing zero bits in the binary representation of this integer.
+    ///
+    /// - Note: 0 is considered to have zero trailing zero bits.
+    /// - Returns: A value in `0...width`.
+    /// - Complexity: O(count)
+    public var trailingZeroBitCount: Int {
+        guard count > 0 else { return 0 }
+        let i = self.words.firstIndex { $0 != 0 }!
+        return i * Word.bitWidth + self[i].trailingZeroBitCount
+    }
+}
+
+extension BigInt {
+    public var bitWidth: Int {
+        guard !magnitude.isZero else { return 0 }
+        return magnitude.bitWidth + 1
+    }
+
+    public var trailingZeroBitCount: Int {
+        // Amazingly, this works fine for negative numbers
+        return magnitude.trailingZeroBitCount
+    }
+}
+
+extension BigUInt {
+    public struct Words: RandomAccessCollection {
+        private let value: BigUInt
+
+        fileprivate init(_ value: BigUInt) { self.value = value }
+
+        public var startIndex: Int { return 0 }
+        public var endIndex: Int { return value.count }
+
+        public subscript(_ index: Int) -> Word {
+            return value[index]
+        }
+    }
+
+    public var words: Words { return Words(self) }
+
+    public init<Words: Sequence>(words: Words) where Words.Element == Word {
+        let uc = words.underestimatedCount
+        if uc > 2 {
+            self.init(words: Array(words))
+        }
+        else {
+            var it = words.makeIterator()
+            guard let w0 = it.next() else {
+                self.init()
+                return
+            }
+            guard let w1 = it.next() else {
+                self.init(word: w0)
+                return
+            }
+            if let w2 = it.next() {
+                var words: [UInt] = []
+                words.reserveCapacity(Swift.max(3, uc))
+                words.append(w0)
+                words.append(w1)
+                words.append(w2)
+                while let word = it.next() {
+                    words.append(word)
+                }
+                self.init(words: words)
+            }
+            else {
+                self.init(low: w0, high: w1)
+            }
+        }
+    }
+}
+
+extension BigInt {
+    public struct Words: RandomAccessCollection {
+        public typealias Indices = CountableRange<Int>
+
+        private let value: BigInt
+        private let decrementLimit: Int
+
+        fileprivate init(_ value: BigInt) {
+            self.value = value
+            switch value.sign {
+            case .plus:
+                self.decrementLimit = 0
+            case .minus:
+                assert(!value.magnitude.isZero)
+                self.decrementLimit = value.magnitude.words.firstIndex(where: { $0 != 0 })!
+            }
+        }
+
+        public var count: Int {
+            switch value.sign {
+            case .plus:
+                if let high = value.magnitude.words.last, high >> (Word.bitWidth - 1) != 0 {
+                    return value.magnitude.count + 1
+                }
+                return value.magnitude.count
+            case .minus:
+                let high = value.magnitude.words.last!
+                if high >> (Word.bitWidth - 1) != 0 {
+                    return value.magnitude.count + 1
+                }
+                return value.magnitude.count
+            }
+        }
+
+        public var indices: Indices { return 0 ..< count }
+        public var startIndex: Int { return 0 }
+        public var endIndex: Int { return count }
+
+        public subscript(_ index: Int) -> UInt {
+            // Note that indices above `endIndex` are accepted.
+            if value.sign == .plus {
+                return value.magnitude[index]
+            }
+            if index <= decrementLimit {
+                return ~(value.magnitude[index] &- 1)
+            }
+            return ~value.magnitude[index]
+        }
+    }
+
+    public var words: Words {
+        return Words(self)
+    }
+
+    public init<S: Sequence>(words: S) where S.Element == Word {
+        var words = Array(words)
+        if (words.last ?? 0) >> (Word.bitWidth - 1) == 0 {
+            self.init(sign: .plus, magnitude: BigUInt(words: words))
+        }
+        else {
+            words.twosComplement()
+            self.init(sign: .minus, magnitude: BigUInt(words: words))
+        }
+    }
+}

Pods/Kingfisher/LICENSE

@@ -0,0 +1,22 @@
+The MIT License (MIT)
+
+Copyright (c) 2019 Wei Wang
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+

Pods/Kingfisher/README.md

@@ -0,0 +1,259 @@
+<p align="center">
+<img src="https://raw.githubusercontent.com/onevcat/Kingfisher/master/images/logo.png" alt="Kingfisher" title="Kingfisher" width="557"/>
+</p>
+
+<p align="center">
+<a href="https://github.com/onevcat/Kingfisher/actions?query=workflow%3Abuild"><img src="https://github.com/onevcat/kingfisher/workflows/build/badge.svg?branch=master"></a>
+<a href="https://swiftpackageindex.com/onevcat/Kingfisher/master/documentation/kingfisher"><img src="https://img.shields.io/badge/Swift-Doc-DE5C43.svg?style=flat"></a>
+<a href="https://cocoapods.org/pods/Kingfisher"><img src="https://img.shields.io/github/v/tag/onevcat/Kingfisher.svg?color=blue&include_prereleases=&sort=semver"></a>
+<a href="https://swift.org/package-manager/"><img src="https://img.shields.io/badge/SPM-supported-DE5C43.svg?style=flat"></a>
+<a href="https://raw.githubusercontent.com/onevcat/Kingfisher/master/LICENSE"><img src="https://img.shields.io/badge/license-MIT-black"></a>
+</p>
+
+Kingfisher is a powerful, pure-Swift library for downloading and caching images from the web. It provides you a chance to use a pure-Swift way to work with remote images in your next app.
+
+## Features
+
+- [x] Asynchronous image downloading and caching.
+- [x] Loading image from either `URLSession`-based networking or local provided data.
+- [x] Useful image processors and filters provided.
+- [x] Multiple-layer hybrid cache for both memory and disk.
+- [x] Fine control on cache behavior. Customizable expiration date and size limit.
+- [x] Cancelable downloading and auto-reusing previous downloaded content to improve performance.
+- [x] Independent components. Use the downloader, caching system, and image processors separately as you need.
+- [x] Prefetching images and showing them from the cache to boost your app.
+- [x] Extensions for `UIImageView`, `NSImageView`, `NSButton`, `UIButton`, `NSTextAttachment`, `WKInterfaceImage`, `TVMonogramView` and `CPListItem` to directly set an image from a URL.
+- [x] Built-in transition animation when setting images.
+- [x] Customizable placeholder and indicator while loading images.
+- [x] Extensible image processing and image format easily.
+- [x] Low Data Mode support.
+- [x] SwiftUI support.
+
+### Kingfisher 101
+
+The simplest use-case is setting an image to an image view with the `UIImageView` extension:
+
+```swift
+import Kingfisher
+
+let url = URL(string: "https://example.com/image.png")
+imageView.kf.setImage(with: url)
+```
+
+Kingfisher will download the image from `url`, send it to both memory cache and disk cache, and display it in `imageView`. 
+When you set it with the same URL later, the image will be retrieved from the cache and shown immediately.
+
+It also works if you use SwiftUI:
+
+```swift
+var body: some View {
+    KFImage(URL(string: "https://example.com/image.png")!)
+}
+```
+
+### A More Advanced Example
+
+With the powerful options, you can do hard tasks with Kingfisher in a simple way. For example, the code below: 
+
+1. Downloads a high-resolution image.
+2. Downsamples it to match the image view size.
+3. Makes it round cornered with a given radius.
+4. Shows a system indicator and a placeholder image while downloading.
+5. When prepared, it animates the small thumbnail image with a "fade in" effect. 
+6. The original large image is also cached to disk for later use, to get rid of downloading it again in a detail view.
+7. A console log is printed when the task finishes, either for success or failure.
+
+```swift
+let url = URL(string: "https://example.com/high_resolution_image.png")
+let processor = DownsamplingImageProcessor(size: imageView.bounds.size)
+             |> RoundCornerImageProcessor(cornerRadius: 20)
+imageView.kf.indicatorType = .activity
+imageView.kf.setImage(
+    with: url,
+    placeholder: UIImage(named: "placeholderImage"),
+    options: [
+        .processor(processor),
+        .scaleFactor(UIScreen.main.scale),
+        .transition(.fade(1)),
+        .cacheOriginalImage
+    ])
+{
+    result in
+    switch result {
+    case .success(let value):
+        print("Task done for: \(value.source.url?.absoluteString ?? "")")
+    case .failure(let error):
+        print("Job failed: \(error.localizedDescription)")
+    }
+}
+```
+
+It is a common situation I can meet in my daily work. Think about how many lines you need to write without
+Kingfisher!
+
+### Method Chaining
+
+If you are not a fan of the `kf` extension, you can also prefer to use the `KF` builder and chained the method 
+invocations. The code below is doing the same thing:
+
+```swift
+// Use `kf` extension
+imageView.kf.setImage(
+    with: url,
+    placeholder: placeholderImage,
+    options: [
+        .processor(processor),
+        .loadDiskFileSynchronously,
+        .cacheOriginalImage,
+        .transition(.fade(0.25)),
+        .lowDataMode(.network(lowResolutionURL))
+    ],
+    progressBlock: { receivedSize, totalSize in
+        // Progress updated
+    },
+    completionHandler: { result in
+        // Done
+    }
+)
+
+// Use `KF` builder
+KF.url(url)
+  .placeholder(placeholderImage)
+  .setProcessor(processor)
+  .loadDiskFileSynchronously()
+  .cacheMemoryOnly()
+  .fade(duration: 0.25)
+  .lowDataModeSource(.network(lowResolutionURL))
+  .onProgress { receivedSize, totalSize in  }
+  .onSuccess { result in  }
+  .onFailure { error in }
+  .set(to: imageView)
+```
+
+And even better, if later you want to switch to SwiftUI, just change the `KF` above to `KFImage`, and you've done:
+
+```swift
+struct ContentView: View {
+    var body: some View {
+        KFImage.url(url)
+          .placeholder(placeholderImage)
+          .setProcessor(processor)
+          .loadDiskFileSynchronously()
+          .cacheMemoryOnly()
+          .fade(duration: 0.25)
+          .lowDataModeSource(.network(lowResolutionURL))
+          .onProgress { receivedSize, totalSize in  }
+          .onSuccess { result in  }
+          .onFailure { error in }
+    }
+}
+```
+
+### Learn More
+
+To learn the use of Kingfisher by more examples, take a look at the well-prepared [Cheat Sheet](https://github.com/onevcat/Kingfisher/wiki/Cheat-Sheet).
+There we summarized the most common tasks in Kingfisher, you can get a better idea of what this framework can do. 
+There are also some performance tips, remember to check them too.
+
+## Requirements
+
+- iOS 12.0+ / macOS 10.14+ / tvOS 12.0+ / watchOS 5.0+ (if you use only UIKit/AppKit)
+- iOS 14.0+ / macOS 11.0+ / tvOS 14.0+ / watchOS 7.0+ (if you use it in SwiftUI)
+- Swift 5.0+
+
+> If you need support from iOS 10 (UIKit/AppKit) or iOS 13 (SwiftUI), use Kingfisher version 6.x. But it won't work 
+> with Xcode 13.0 and Xcode 13.1 [#1802](https://github.com/onevcat/Kingfisher/issues/1802).
+>
+> If you need to use Xcode 13.0 and 13.1 but cannot upgrade to v7, use the `version6-xcode13` branch. However, you have to drop 
+> iOS 10 support due to another Xcode 13 bug.
+>
+> | UIKit | SwiftUI | Xcode | Kingfisher |
+> |---|---|---|---|
+> | iOS 10+ | iOS 13+ | 12 | ~> 6.3.1 |
+> | iOS 11+ | iOS 13+ | 13 | `version6-xcode13` |
+> | iOS 12+ | iOS 14+ | 13 | ~> 7.0 |
+
+### Installation
+
+A detailed guide for installation can be found in [Installation Guide](https://github.com/onevcat/Kingfisher/wiki/Installation-Guide).
+
+#### Swift Package Manager
+
+- File > Swift Packages > Add Package Dependency
+- Add `https://github.com/onevcat/Kingfisher.git`
+- Select "Up to Next Major" with "7.0.0"
+
+#### CocoaPods
+
+```ruby
+source 'https://github.com/CocoaPods/Specs.git'
+platform :ios, '12.0'
+use_frameworks!
+
+target 'MyApp' do
+  pod 'Kingfisher', '~> 7.0'
+end
+```
+
+#### Carthage
+
+```
+github "onevcat/Kingfisher" ~> 7.0
+```
+
+
+### Migrating
+
+[Kingfisher 7.0 Migration](https://github.com/onevcat/Kingfisher/wiki/Kingfisher-7.0-Migration-Guide) - Kingfisher 7.x is NOT fully compatible with the previous version. However, changes should be trivial or not required at all. Please follow the [migration guide](https://github.com/onevcat/Kingfisher/wiki/Kingfisher-7.0-Migration-Guide) when you prepare to upgrade Kingfisher in your project.
+
+If you are using an even earlier version, see the guides below to know the steps for migrating.
+
+> - [Kingfisher 6.0 Migration](https://github.com/onevcat/Kingfisher/wiki/Kingfisher-6.0-Migration-Guide) - Kingfisher 6.x is NOT fully compatible with the previous version. However, migration is not difficult. Depending on your use cases, it may take no effect or several minutes to modify your existing code for the new version. Please follow the [migration guide](https://github.com/onevcat/Kingfisher/wiki/Kingfisher-6.0-Migration-Guide) when you prepare to upgrade Kingfisher in your project.
+> - [Kingfisher 5.0 Migration](https://github.com/onevcat/Kingfisher/wiki/Kingfisher-5.0-Migration-Guide) - If you are upgrading to Kingfisher 5.x from 4.x, please read this for more information.
+> - Kingfisher 4.0 Migration - Kingfisher 3.x should be source compatible to Kingfisher 4. The reason for a major update is that we need to specify the Swift version explicitly for Xcode. All deprecated methods in Kingfisher 3 were removed, so please ensure you have no warning left before you migrate from Kingfisher 3 with Kingfisher 4. If you have any trouble when migrating, please open an issue to discuss.
+> - [Kingfisher 3.0 Migration](https://github.com/onevcat/Kingfisher/wiki/Kingfisher-3.0-Migration-Guide) - If you are upgrading to Kingfisher 3.x from an earlier version, please read this for more information.
+
+## Next Steps
+
+We prepared a [wiki page](https://github.com/onevcat/Kingfisher/wiki). You can find tons of useful things there.
+
+* [Installation Guide](https://github.com/onevcat/Kingfisher/wiki/Installation-Guide) - Follow it to integrate Kingfisher into your project.
+* [Cheat Sheet](https://github.com/onevcat/Kingfisher/wiki/Cheat-Sheet)- Curious about what Kingfisher could do and how would it look like when used in your project? See this page for useful code snippets. If you are already familiar with Kingfisher, you could also learn new tricks to improve the way you use Kingfisher!
+* [API Reference](https://swiftpackageindex.com/onevcat/Kingfisher/master/documentation/kingfisher) - Lastly, please remember to read the full API reference whenever you need more detailed documentation.
+
+## Other
+
+### Future of Kingfisher
+
+I want to keep Kingfisher lightweight. This framework focuses on providing a simple solution for downloading and caching images. This doesn’t mean the framework can’t be improved. Kingfisher is far from perfect, so necessary and useful updates will be made to make it better.
+
+### Developments and Tests
+
+Any contributing and pull requests are warmly welcome. However, before you plan to implement some features or try to fix an uncertain issue, it is recommended to open a discussion first. It would be appreciated if your pull requests could build with all tests green. :)
+
+### About the logo
+
+The logo of Kingfisher is inspired by [Tangram (七巧板)](http://en.wikipedia.org/wiki/Tangram), a dissection puzzle consisting of seven flat shapes from China. I believe she's a kingfisher bird instead of a swift, but someone insists that she is a pigeon. I guess I should give her a name. Hi, guys, do you have any suggestions?
+
+### Contact
+
+Follow and contact me on [Twitter](http://twitter.com/onevcat) or [Sina Weibo](http://weibo.com/onevcat). If you find an issue, [open a ticket](https://github.com/onevcat/Kingfisher/issues/new). Pull requests are warmly welcome as well.
+
+## Backers & Sponsors
+
+Open-source projects cannot live long without your help. If you find Kingfisher to be useful, please consider supporting this 
+project by becoming a sponsor. Your user icon or company logo shows up [on my blog](https://onevcat.com/tabs/about/) with a link to your home page. 
+
+Become a sponsor through [GitHub Sponsors](https://github.com/sponsors/onevcat). :heart:
+
+Special thanks to:
+
+[![imgly](https://user-images.githubusercontent.com/1812216/106253726-271ed000-6218-11eb-98e0-c9c681925770.png)](https://img.ly/)
+
+[![emergetools](https://github-production-user-asset-6210df.s3.amazonaws.com/1019875/254794187-d44f6f50-993f-42e3-b79c-960f69c4adc1.png)](https://www.emergetools.com)
+
+
+
+### License
+
+Kingfisher is released under the MIT license. See LICENSE for details.

Pods/Kingfisher/Sources/Cache/CacheSerializer.swift

@@ -0,0 +1,137 @@
+//
+//  CacheSerializer.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2016/09/02.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+import CoreGraphics
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+/// An `CacheSerializer` is used to convert some data to an image object after
+/// retrieving it from disk storage, and vice versa, to convert an image to data object
+/// for storing to the disk storage.
+public protocol CacheSerializer {
+    
+    /// Gets the serialized data from a provided image
+    /// and optional original data for caching to disk.
+    ///
+    /// - Parameters:
+    ///   - image: The image needed to be serialized.
+    ///   - original: The original data which is just downloaded.
+    ///               If the image is retrieved from cache instead of
+    ///               downloaded, it will be `nil`.
+    /// - Returns: The data object for storing to disk, or `nil` when no valid
+    ///            data could be serialized.
+    func data(with image: KFCrossPlatformImage, original: Data?) -> Data?
+
+    /// Gets an image from provided serialized data.
+    ///
+    /// - Parameters:
+    ///   - data: The data from which an image should be deserialized.
+    ///   - options: The parsed options for deserialization.
+    /// - Returns: An image deserialized or `nil` when no valid image
+    ///            could be deserialized.
+    func image(with data: Data, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage?
+    
+    /// Whether this serializer prefers to cache the original data in its implementation.
+    /// If `true`, after creating the image from the disk data, Kingfisher will continue to apply the processor to get
+    /// the final image.
+    ///
+    /// By default, it is `false` and the actual processed image is assumed to be serialized to the disk.
+    var originalDataUsed: Bool { get }
+}
+
+public extension CacheSerializer {
+    var originalDataUsed: Bool { false }
+}
+
+/// Represents a basic and default `CacheSerializer` used in Kingfisher disk cache system.
+/// It could serialize and deserialize images in PNG, JPEG and GIF format. For
+/// image other than these formats, a normalized `pngRepresentation` will be used.
+public struct DefaultCacheSerializer: CacheSerializer {
+    
+    /// The default general cache serializer used across Kingfisher's cache.
+    public static let `default` = DefaultCacheSerializer()
+
+    /// The compression quality when converting image to a lossy format data. Default is 1.0.
+    public var compressionQuality: CGFloat = 1.0
+
+    /// Whether the original data should be preferred when serializing the image.
+    /// If `true`, the input original data will be checked first and used unless the data is `nil`.
+    /// In that case, the serialization will fall back to creating data from image.
+    public var preferCacheOriginalData: Bool = false
+
+    /// Returnes the `preferCacheOriginalData` value. When the original data is used, Kingfisher needs to re-apply the
+    /// processors to get the desired final image.
+    public var originalDataUsed: Bool { preferCacheOriginalData }
+    
+    /// Creates a cache serializer that serialize and deserialize images in PNG, JPEG and GIF format.
+    ///
+    /// - Note:
+    /// Use `DefaultCacheSerializer.default` unless you need to specify your own properties.
+    ///
+    public init() { }
+
+    /// - Parameters:
+    ///   - image: The image needed to be serialized.
+    ///   - original: The original data which is just downloaded.
+    ///               If the image is retrieved from cache instead of
+    ///               downloaded, it will be `nil`.
+    /// - Returns: The data object for storing to disk, or `nil` when no valid
+    ///            data could be serialized.
+    ///
+    /// - Note:
+    /// Only when `original` contains valid PNG, JPEG and GIF format data, the `image` will be
+    /// converted to the corresponding data type. Otherwise, if the `original` is provided but it is not
+    /// If `original` is `nil`, the input `image` will be encoded as PNG data.
+    public func data(with image: KFCrossPlatformImage, original: Data?) -> Data? {
+        if preferCacheOriginalData {
+            return original ??
+                image.kf.data(
+                    format: original?.kf.imageFormat ?? .unknown,
+                    compressionQuality: compressionQuality
+                )
+        } else {
+            return image.kf.data(
+                format: original?.kf.imageFormat ?? .unknown,
+                compressionQuality: compressionQuality
+            )
+        }
+    }
+    
+    /// Gets an image deserialized from provided data.
+    ///
+    /// - Parameters:
+    ///   - data: The data from which an image should be deserialized.
+    ///   - options: Options for deserialization.
+    /// - Returns: An image deserialized or `nil` when no valid image
+    ///            could be deserialized.
+    public func image(with data: Data, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        return KingfisherWrapper.image(data: data, options: options.imageCreatingOptions)
+    }
+}

Pods/Kingfisher/Sources/Cache/DiskStorage.swift

@@ -0,0 +1,616 @@
+//
+//  DiskStorage.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2018/10/15.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+
+/// Represents a set of conception related to storage which stores a certain type of value in disk.
+/// This is a namespace for the disk storage types. A `Backend` with a certain `Config` will be used to describe the
+/// storage. See these composed types for more information.
+public enum DiskStorage {
+
+    /// Represents a storage back-end for the `DiskStorage`. The value is serialized to data
+    /// and stored as file in the file system under a specified location.
+    ///
+    /// You can config a `DiskStorage.Backend` in its initializer by passing a `DiskStorage.Config` value.
+    /// or modifying the `config` property after it being created. `DiskStorage` will use file's attributes to keep
+    /// track of a file for its expiration or size limitation.
+    public class Backend<T: DataTransformable> {
+        /// The config used for this disk storage.
+        public var config: Config
+
+        // The final storage URL on disk, with `name` and `cachePathBlock` considered.
+        public let directoryURL: URL
+
+        let metaChangingQueue: DispatchQueue
+
+        var maybeCached : Set<String>?
+        let maybeCachedCheckingQueue = DispatchQueue(label: "com.onevcat.Kingfisher.maybeCachedCheckingQueue")
+
+        // `false` if the storage initialized with an error. This prevents unexpected forcibly crash when creating
+        // storage in the default cache.
+        private var storageReady: Bool = true
+
+        /// Creates a disk storage with the given `DiskStorage.Config`.
+        ///
+        /// - Parameter config: The config used for this disk storage.
+        /// - Throws: An error if the folder for storage cannot be got or created.
+        public convenience init(config: Config) throws {
+            self.init(noThrowConfig: config, creatingDirectory: false)
+            try prepareDirectory()
+        }
+
+        // If `creatingDirectory` is `false`, the directory preparation will be skipped.
+        // We need to call `prepareDirectory` manually after this returns.
+        init(noThrowConfig config: Config, creatingDirectory: Bool) {
+            var config = config
+
+            let creation = Creation(config)
+            self.directoryURL = creation.directoryURL
+
+            // Break any possible retain cycle set by outside.
+            config.cachePathBlock = nil
+            self.config = config
+
+            metaChangingQueue = DispatchQueue(label: creation.cacheName)
+            setupCacheChecking()
+
+            if creatingDirectory {
+                try? prepareDirectory()
+            }
+        }
+
+        private func setupCacheChecking() {
+            maybeCachedCheckingQueue.async {
+                do {
+                    self.maybeCached = Set()
+                    try self.config.fileManager.contentsOfDirectory(atPath: self.directoryURL.path).forEach { fileName in
+                        self.maybeCached?.insert(fileName)
+                    }
+                } catch {
+                    // Just disable the functionality if we fail to initialize it properly. This will just revert to
+                    // the behavior which is to check file existence on disk directly.
+                    self.maybeCached = nil
+                }
+            }
+        }
+
+        // Creates the storage folder.
+        private func prepareDirectory() throws {
+            let fileManager = config.fileManager
+            let path = directoryURL.path
+
+            guard !fileManager.fileExists(atPath: path) else { return }
+
+            do {
+                try fileManager.createDirectory(
+                    atPath: path,
+                    withIntermediateDirectories: true,
+                    attributes: nil)
+            } catch {
+                self.storageReady = false
+                throw KingfisherError.cacheError(reason: .cannotCreateDirectory(path: path, error: error))
+            }
+        }
+
+        /// Stores a value to the storage under the specified key and expiration policy.
+        /// - Parameters:
+        ///   - value: The value to be stored.
+        ///   - key: The key to which the `value` will be stored. If there is already a value under the key,
+        ///          the old value will be overwritten by `value`.
+        ///   - expiration: The expiration policy used by this store action.
+        ///   - writeOptions: Data writing options used the new files.
+        /// - Throws: An error during converting the value to a data format or during writing it to disk.
+        public func store(
+            value: T,
+            forKey key: String,
+            expiration: StorageExpiration? = nil,
+            writeOptions: Data.WritingOptions = []) throws
+        {
+            guard storageReady else {
+                throw KingfisherError.cacheError(reason: .diskStorageIsNotReady(cacheURL: directoryURL))
+            }
+
+            let expiration = expiration ?? config.expiration
+            // The expiration indicates that already expired, no need to store.
+            guard !expiration.isExpired else { return }
+            
+            let data: Data
+            do {
+                data = try value.toData()
+            } catch {
+                throw KingfisherError.cacheError(reason: .cannotConvertToData(object: value, error: error))
+            }
+
+            let fileURL = cacheFileURL(forKey: key)
+            do {
+                try data.write(to: fileURL, options: writeOptions)
+            } catch {
+                if error.isFolderMissing {
+                    // The whole cache folder is deleted. Try to recreate it and write file again.
+                    do {
+                        try prepareDirectory()
+                        try data.write(to: fileURL, options: writeOptions)
+                    } catch {
+                        throw KingfisherError.cacheError(
+                            reason: .cannotCreateCacheFile(fileURL: fileURL, key: key, data: data, error: error)
+                        )
+                    }
+                } else {
+                    throw KingfisherError.cacheError(
+                        reason: .cannotCreateCacheFile(fileURL: fileURL, key: key, data: data, error: error)
+                    )
+                }
+            }
+
+            let now = Date()
+            let attributes: [FileAttributeKey : Any] = [
+                // The last access date.
+                .creationDate: now.fileAttributeDate,
+                // The estimated expiration date.
+                .modificationDate: expiration.estimatedExpirationSinceNow.fileAttributeDate
+            ]
+            do {
+                try config.fileManager.setAttributes(attributes, ofItemAtPath: fileURL.path)
+            } catch {
+                try? config.fileManager.removeItem(at: fileURL)
+                throw KingfisherError.cacheError(
+                    reason: .cannotSetCacheFileAttribute(
+                        filePath: fileURL.path,
+                        attributes: attributes,
+                        error: error
+                    )
+                )
+            }
+
+            maybeCachedCheckingQueue.async {
+                self.maybeCached?.insert(fileURL.lastPathComponent)
+            }
+        }
+
+        /// Gets a value from the storage.
+        /// - Parameters:
+        ///   - key: The cache key of value.
+        ///   - extendingExpiration: The expiration policy used by this getting action.
+        /// - Throws: An error during converting the data to a value or during operation of disk files.
+        /// - Returns: The value under `key` if it is valid and found in the storage. Otherwise, `nil`.
+        public func value(forKey key: String, extendingExpiration: ExpirationExtending = .cacheTime) throws -> T? {
+            return try value(forKey: key, referenceDate: Date(), actuallyLoad: true, extendingExpiration: extendingExpiration)
+        }
+
+        func value(
+            forKey key: String,
+            referenceDate: Date,
+            actuallyLoad: Bool,
+            extendingExpiration: ExpirationExtending) throws -> T?
+        {
+            guard storageReady else {
+                throw KingfisherError.cacheError(reason: .diskStorageIsNotReady(cacheURL: directoryURL))
+            }
+
+            let fileManager = config.fileManager
+            let fileURL = cacheFileURL(forKey: key)
+            let filePath = fileURL.path
+
+            let fileMaybeCached = maybeCachedCheckingQueue.sync {
+                return maybeCached?.contains(fileURL.lastPathComponent) ?? true
+            }
+            guard fileMaybeCached else {
+                return nil
+            }
+            guard fileManager.fileExists(atPath: filePath) else {
+                return nil
+            }
+
+            let meta: FileMeta
+            do {
+                let resourceKeys: Set<URLResourceKey> = [.contentModificationDateKey, .creationDateKey]
+                meta = try FileMeta(fileURL: fileURL, resourceKeys: resourceKeys)
+            } catch {
+                throw KingfisherError.cacheError(
+                    reason: .invalidURLResource(error: error, key: key, url: fileURL))
+            }
+
+            if meta.expired(referenceDate: referenceDate) {
+                return nil
+            }
+            if !actuallyLoad { return T.empty }
+
+            do {
+                let data = try Data(contentsOf: fileURL)
+                let obj = try T.fromData(data)
+                metaChangingQueue.async {
+                    meta.extendExpiration(with: fileManager, extendingExpiration: extendingExpiration)
+                }
+                return obj
+            } catch {
+                throw KingfisherError.cacheError(reason: .cannotLoadDataFromDisk(url: fileURL, error: error))
+            }
+        }
+
+        /// Whether there is valid cached data under a given key.
+        /// - Parameter key: The cache key of value.
+        /// - Returns: If there is valid data under the key, `true`. Otherwise, `false`.
+        ///
+        /// - Note:
+        /// This method does not actually load the data from disk, so it is faster than directly loading the cached value
+        /// by checking the nullability of `value(forKey:extendingExpiration:)` method.
+        ///
+        public func isCached(forKey key: String) -> Bool {
+            return isCached(forKey: key, referenceDate: Date())
+        }
+
+        /// Whether there is valid cached data under a given key and a reference date.
+        /// - Parameters:
+        ///   - key: The cache key of value.
+        ///   - referenceDate: A reference date to check whether the cache is still valid.
+        /// - Returns: If there is valid data under the key, `true`. Otherwise, `false`.
+        ///
+        /// - Note:
+        /// If you pass `Date()` to `referenceDate`, this method is identical to `isCached(forKey:)`. Use the
+        /// `referenceDate` to determine whether the cache is still valid for a future date.
+        public func isCached(forKey key: String, referenceDate: Date) -> Bool {
+            do {
+                let result = try value(
+                    forKey: key,
+                    referenceDate: referenceDate,
+                    actuallyLoad: false,
+                    extendingExpiration: .none
+                )
+                return result != nil
+            } catch {
+                return false
+            }
+        }
+
+        /// Removes a value from a specified key.
+        /// - Parameter key: The cache key of value.
+        /// - Throws: An error during removing the value.
+        public func remove(forKey key: String) throws {
+            let fileURL = cacheFileURL(forKey: key)
+            try removeFile(at: fileURL)
+        }
+
+        func removeFile(at url: URL) throws {
+            try config.fileManager.removeItem(at: url)
+        }
+
+        /// Removes all values in this storage.
+        /// - Throws: An error during removing the values.
+        public func removeAll() throws {
+            try removeAll(skipCreatingDirectory: false)
+        }
+
+        func removeAll(skipCreatingDirectory: Bool) throws {
+            try config.fileManager.removeItem(at: directoryURL)
+            if !skipCreatingDirectory {
+                try prepareDirectory()
+            }
+        }
+
+        /// The URL of the cached file with a given computed `key`.
+        ///
+        /// - Parameter key: The final computed key used when caching the image. Please note that usually this is not
+        /// the `cacheKey` of an image `Source`. It is the computed key with processor identifier considered.
+        ///
+        /// - Note:
+        /// This method does not guarantee there is an image already cached in the returned URL. It just gives your
+        /// the URL that the image should be if it exists in disk storage, with the give key.
+        ///
+        public func cacheFileURL(forKey key: String) -> URL {
+            let fileName = cacheFileName(forKey: key)
+            return directoryURL.appendingPathComponent(fileName, isDirectory: false)
+        }
+
+        func cacheFileName(forKey key: String) -> String {
+            if config.usesHashedFileName {
+                let hashedKey = key.kf.md5
+                if let ext = config.pathExtension {
+                    return "\(hashedKey).\(ext)"
+                } else if config.autoExtAfterHashedFileName,
+                          let ext = key.kf.ext {
+                    return "\(hashedKey).\(ext)"
+                }
+                return hashedKey
+            } else {
+                if let ext = config.pathExtension {
+                    return "\(key).\(ext)"
+                }
+                return key
+            }
+        }
+
+        func allFileURLs(for propertyKeys: [URLResourceKey]) throws -> [URL] {
+            let fileManager = config.fileManager
+
+            guard let directoryEnumerator = fileManager.enumerator(
+                at: directoryURL, includingPropertiesForKeys: propertyKeys, options: .skipsHiddenFiles) else
+            {
+                throw KingfisherError.cacheError(reason: .fileEnumeratorCreationFailed(url: directoryURL))
+            }
+
+            guard let urls = directoryEnumerator.allObjects as? [URL] else {
+                throw KingfisherError.cacheError(reason: .invalidFileEnumeratorContent(url: directoryURL))
+            }
+            return urls
+        }
+
+        /// Removes all expired values from this storage.
+        /// - Throws: A file manager error during removing the file.
+        /// - Returns: The URLs for removed files.
+        public func removeExpiredValues() throws -> [URL] {
+            return try removeExpiredValues(referenceDate: Date())
+        }
+
+        func removeExpiredValues(referenceDate: Date) throws -> [URL] {
+            let propertyKeys: [URLResourceKey] = [
+                .isDirectoryKey,
+                .contentModificationDateKey
+            ]
+
+            let urls = try allFileURLs(for: propertyKeys)
+            let keys = Set(propertyKeys)
+            let expiredFiles = urls.filter { fileURL in
+                do {
+                    let meta = try FileMeta(fileURL: fileURL, resourceKeys: keys)
+                    if meta.isDirectory {
+                        return false
+                    }
+                    return meta.expired(referenceDate: referenceDate)
+                } catch {
+                    return true
+                }
+            }
+            try expiredFiles.forEach { url in
+                try removeFile(at: url)
+            }
+            return expiredFiles
+        }
+
+        /// Removes all size exceeded values from this storage.
+        /// - Throws: A file manager error during removing the file.
+        /// - Returns: The URLs for removed files.
+        ///
+        /// - Note: This method checks `config.sizeLimit` and remove cached files in an LRU (Least Recently Used) way.
+        func removeSizeExceededValues() throws -> [URL] {
+
+            if config.sizeLimit == 0 { return [] } // Back compatible. 0 means no limit.
+
+            var size = try totalSize()
+            if size < config.sizeLimit { return [] }
+
+            let propertyKeys: [URLResourceKey] = [
+                .isDirectoryKey,
+                .creationDateKey,
+                .fileSizeKey
+            ]
+            let keys = Set(propertyKeys)
+
+            let urls = try allFileURLs(for: propertyKeys)
+            var pendings: [FileMeta] = urls.compactMap { fileURL in
+                guard let meta = try? FileMeta(fileURL: fileURL, resourceKeys: keys) else {
+                    return nil
+                }
+                return meta
+            }
+            // Sort by last access date. Most recent file first.
+            pendings.sort(by: FileMeta.lastAccessDate)
+
+            var removed: [URL] = []
+            let target = config.sizeLimit / 2
+            while size > target, let meta = pendings.popLast() {
+                size -= UInt(meta.fileSize)
+                try removeFile(at: meta.url)
+                removed.append(meta.url)
+            }
+            return removed
+        }
+
+        /// Gets the total file size of the folder in bytes.
+        public func totalSize() throws -> UInt {
+            let propertyKeys: [URLResourceKey] = [.fileSizeKey]
+            let urls = try allFileURLs(for: propertyKeys)
+            let keys = Set(propertyKeys)
+            let totalSize: UInt = urls.reduce(0) { size, fileURL in
+                do {
+                    let meta = try FileMeta(fileURL: fileURL, resourceKeys: keys)
+                    return size + UInt(meta.fileSize)
+                } catch {
+                    return size
+                }
+            }
+            return totalSize
+        }
+    }
+}
+
+extension DiskStorage {
+    /// Represents the config used in a `DiskStorage`.
+    public struct Config {
+
+        /// The file size limit on disk of the storage in bytes. 0 means no limit.
+        public var sizeLimit: UInt
+
+        /// The `StorageExpiration` used in this disk storage. Default is `.days(7)`,
+        /// means that the disk cache would expire in one week.
+        public var expiration: StorageExpiration = .days(7)
+
+        /// The preferred extension of cache item. It will be appended to the file name as its extension.
+        /// Default is `nil`, means that the cache file does not contain a file extension.
+        public var pathExtension: String? = nil
+
+        /// Default is `true`, means that the cache file name will be hashed before storing.
+        public var usesHashedFileName = true
+
+        /// Default is `false`
+        /// If set to `true`, image extension will be extracted from original file name and append to
+        /// the hased file name and used as the cache key on disk.
+        public var autoExtAfterHashedFileName = false
+        
+        /// Closure that takes in initial directory path and generates
+        /// the final disk cache path. You can use it to fully customize your cache path.
+        public var cachePathBlock: ((_ directory: URL, _ cacheName: String) -> URL)! = {
+            (directory, cacheName) in
+            return directory.appendingPathComponent(cacheName, isDirectory: true)
+        }
+
+        let name: String
+        let fileManager: FileManager
+        let directory: URL?
+
+        /// Creates a config value based on given parameters.
+        ///
+        /// - Parameters:
+        ///   - name: The name of cache. It is used as a part of storage folder. It is used to identify the disk
+        ///           storage. Two storages with the same `name` would share the same folder in disk, and it should
+        ///           be prevented.
+        ///   - sizeLimit: The size limit in bytes for all existing files in the disk storage.
+        ///   - fileManager: The `FileManager` used to manipulate files on disk. Default is `FileManager.default`.
+        ///   - directory: The URL where the disk storage should live. The storage will use this as the root folder,
+        ///                and append a path which is constructed by input `name`. Default is `nil`, indicates that
+        ///                the cache directory under user domain mask will be used.
+        public init(
+            name: String,
+            sizeLimit: UInt,
+            fileManager: FileManager = .default,
+            directory: URL? = nil)
+        {
+            self.name = name
+            self.fileManager = fileManager
+            self.directory = directory
+            self.sizeLimit = sizeLimit
+        }
+    }
+}
+
+extension DiskStorage {
+    struct FileMeta {
+    
+        let url: URL
+        
+        let lastAccessDate: Date?
+        let estimatedExpirationDate: Date?
+        let isDirectory: Bool
+        let fileSize: Int
+        
+        static func lastAccessDate(lhs: FileMeta, rhs: FileMeta) -> Bool {
+            return lhs.lastAccessDate ?? .distantPast > rhs.lastAccessDate ?? .distantPast
+        }
+        
+        init(fileURL: URL, resourceKeys: Set<URLResourceKey>) throws {
+            let meta = try fileURL.resourceValues(forKeys: resourceKeys)
+            self.init(
+                fileURL: fileURL,
+                lastAccessDate: meta.creationDate,
+                estimatedExpirationDate: meta.contentModificationDate,
+                isDirectory: meta.isDirectory ?? false,
+                fileSize: meta.fileSize ?? 0)
+        }
+        
+        init(
+            fileURL: URL,
+            lastAccessDate: Date?,
+            estimatedExpirationDate: Date?,
+            isDirectory: Bool,
+            fileSize: Int)
+        {
+            self.url = fileURL
+            self.lastAccessDate = lastAccessDate
+            self.estimatedExpirationDate = estimatedExpirationDate
+            self.isDirectory = isDirectory
+            self.fileSize = fileSize
+        }
+
+        func expired(referenceDate: Date) -> Bool {
+            return estimatedExpirationDate?.isPast(referenceDate: referenceDate) ?? true
+        }
+        
+        func extendExpiration(with fileManager: FileManager, extendingExpiration: ExpirationExtending) {
+            guard let lastAccessDate = lastAccessDate,
+                  let lastEstimatedExpiration = estimatedExpirationDate else
+            {
+                return
+            }
+
+            let attributes: [FileAttributeKey : Any]
+
+            switch extendingExpiration {
+            case .none:
+                // not extending expiration time here
+                return
+            case .cacheTime:
+                let originalExpiration: StorageExpiration =
+                    .seconds(lastEstimatedExpiration.timeIntervalSince(lastAccessDate))
+                attributes = [
+                    .creationDate: Date().fileAttributeDate,
+                    .modificationDate: originalExpiration.estimatedExpirationSinceNow.fileAttributeDate
+                ]
+            case .expirationTime(let expirationTime):
+                attributes = [
+                    .creationDate: Date().fileAttributeDate,
+                    .modificationDate: expirationTime.estimatedExpirationSinceNow.fileAttributeDate
+                ]
+            }
+
+            try? fileManager.setAttributes(attributes, ofItemAtPath: url.path)
+        }
+    }
+}
+
+extension DiskStorage {
+    struct Creation {
+        let directoryURL: URL
+        let cacheName: String
+
+        init(_ config: Config) {
+            let url: URL
+            if let directory = config.directory {
+                url = directory
+            } else {
+                url = config.fileManager.urls(for: .cachesDirectory, in: .userDomainMask)[0]
+            }
+
+            cacheName = "com.onevcat.Kingfisher.ImageCache.\(config.name)"
+            directoryURL = config.cachePathBlock(url, cacheName)
+        }
+    }
+}
+
+fileprivate extension Error {
+    var isFolderMissing: Bool {
+        let nsError = self as NSError
+        guard nsError.domain == NSCocoaErrorDomain, nsError.code == 4 else {
+            return false
+        }
+        guard let underlyingError = nsError.userInfo[NSUnderlyingErrorKey] as? NSError else {
+            return false
+        }
+        guard underlyingError.domain == NSPOSIXErrorDomain, underlyingError.code == 2 else {
+            return false
+        }
+        return true
+    }
+}

Pods/Kingfisher/Sources/Cache/FormatIndicatedCacheSerializer.swift

@@ -0,0 +1,123 @@
+//
+//  RequestModifier.swift
+//  Kingfisher
+//
+//  Created by Junyu Kuang on 5/28/17.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+import CoreGraphics
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+/// `FormatIndicatedCacheSerializer` lets you indicate an image format for serialized caches.
+///
+/// It could serialize and deserialize PNG, JPEG and GIF images. For
+/// image other than these formats, a normalized `pngRepresentation` will be used.
+///
+/// Example:
+/// ````
+/// let profileImageSize = CGSize(width: 44, height: 44)
+///
+/// // A round corner image.
+/// let imageProcessor = RoundCornerImageProcessor(
+///     cornerRadius: profileImageSize.width / 2, targetSize: profileImageSize)
+///
+/// let optionsInfo: KingfisherOptionsInfo = [
+///     .cacheSerializer(FormatIndicatedCacheSerializer.png), 
+///     .processor(imageProcessor)]
+///
+/// A URL pointing to a JPEG image.
+/// let url = URL(string: "https://example.com/image.jpg")!
+///
+/// // Image will be always cached as PNG format to preserve alpha channel for round rectangle.
+/// // So when you load it from cache again later, it will be still round cornered.
+/// // Otherwise, the corner part would be filled by white color (since JPEG does not contain an alpha channel).
+/// imageView.kf.setImage(with: url, options: optionsInfo)
+/// ````
+public struct FormatIndicatedCacheSerializer: CacheSerializer {
+    
+    /// A `FormatIndicatedCacheSerializer` which converts image from and to PNG format. If the image cannot be
+    /// represented by PNG format, it will fallback to its real format which is determined by `original` data.
+    public static let png = FormatIndicatedCacheSerializer(imageFormat: .PNG, jpegCompressionQuality: nil)
+    
+    /// A `FormatIndicatedCacheSerializer` which converts image from and to JPEG format. If the image cannot be
+    /// represented by JPEG format, it will fallback to its real format which is determined by `original` data.
+    /// The compression quality is 1.0 when using this serializer. If you need to set a customized compression quality,
+    /// use `jpeg(compressionQuality:)`.
+    public static let jpeg = FormatIndicatedCacheSerializer(imageFormat: .JPEG, jpegCompressionQuality: 1.0)
+
+    /// A `FormatIndicatedCacheSerializer` which converts image from and to JPEG format with a settable compression
+    /// quality. If the image cannot be represented by JPEG format, it will fallback to its real format which is
+    /// determined by `original` data.
+    /// - Parameter compressionQuality: The compression quality when converting image to JPEG data.
+    public static func jpeg(compressionQuality: CGFloat) -> FormatIndicatedCacheSerializer {
+        return FormatIndicatedCacheSerializer(imageFormat: .JPEG, jpegCompressionQuality: compressionQuality)
+    }
+    
+    /// A `FormatIndicatedCacheSerializer` which converts image from and to GIF format. If the image cannot be
+    /// represented by GIF format, it will fallback to its real format which is determined by `original` data.
+    public static let gif = FormatIndicatedCacheSerializer(imageFormat: .GIF, jpegCompressionQuality: nil)
+    
+    /// The indicated image format.
+    private let imageFormat: ImageFormat
+
+    /// The compression quality used for loss image format (like JPEG).
+    private let jpegCompressionQuality: CGFloat?
+    
+    /// Creates data which represents the given `image` under a format.
+    public func data(with image: KFCrossPlatformImage, original: Data?) -> Data? {
+        
+        func imageData(withFormat imageFormat: ImageFormat) -> Data? {
+            return autoreleasepool { () -> Data? in
+                switch imageFormat {
+                case .PNG: return image.kf.pngRepresentation()
+                case .JPEG: return image.kf.jpegRepresentation(compressionQuality: jpegCompressionQuality ?? 1.0)
+                case .GIF: return image.kf.gifRepresentation()
+                case .unknown: return nil
+                }
+            }
+        }
+        
+        // generate data with indicated image format
+        if let data = imageData(withFormat: imageFormat) {
+            return data
+        }
+        
+        let originalFormat = original?.kf.imageFormat ?? .unknown
+        
+        // generate data with original image's format
+        if originalFormat != imageFormat, let data = imageData(withFormat: originalFormat) {
+            return data
+        }
+        
+        return original ?? image.kf.normalized.kf.pngRepresentation()
+    }
+    
+    /// Same implementation as `DefaultCacheSerializer`.
+    public func image(with data: Data, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        return KingfisherWrapper.image(data: data, options: options.imageCreatingOptions)
+    }
+}

Pods/Kingfisher/Sources/Cache/ImageCache.swift

@@ -0,0 +1,882 @@
+//
+//  ImageCache.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 15/4/6.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+extension Notification.Name {
+    /// This notification will be sent when the disk cache got cleaned either there are cached files expired or the
+    /// total size exceeding the max allowed size. The manually invoking of `clearDiskCache` method will not trigger
+    /// this notification.
+    ///
+    /// The `object` of this notification is the `ImageCache` object which sends the notification.
+    /// A list of removed hashes (files) could be retrieved by accessing the array under
+    /// `KingfisherDiskCacheCleanedHashKey` key in `userInfo` of the notification object you received.
+    /// By checking the array, you could know the hash codes of files are removed.
+    public static let KingfisherDidCleanDiskCache =
+        Notification.Name("com.onevcat.Kingfisher.KingfisherDidCleanDiskCache")
+}
+
+/// Key for array of cleaned hashes in `userInfo` of `KingfisherDidCleanDiskCacheNotification`.
+public let KingfisherDiskCacheCleanedHashKey = "com.onevcat.Kingfisher.cleanedHash"
+
+/// Cache type of a cached image.
+/// - none: The image is not cached yet when retrieving it.
+/// - memory: The image is cached in memory.
+/// - disk: The image is cached in disk.
+public enum CacheType {
+    /// The image is not cached yet when retrieving it.
+    case none
+    /// The image is cached in memory.
+    case memory
+    /// The image is cached in disk.
+    case disk
+    
+    /// Whether the cache type represents the image is already cached or not.
+    public var cached: Bool {
+        switch self {
+        case .memory, .disk: return true
+        case .none: return false
+        }
+    }
+}
+
+/// Represents the caching operation result.
+public struct CacheStoreResult {
+    
+    /// The cache result for memory cache. Caching an image to memory will never fail.
+    public let memoryCacheResult: Result<(), Never>
+    
+    /// The cache result for disk cache. If an error happens during caching operation,
+    /// you can get it from `.failure` case of this `diskCacheResult`.
+    public let diskCacheResult: Result<(), KingfisherError>
+}
+
+extension KFCrossPlatformImage: CacheCostCalculable {
+    /// Cost of an image
+    public var cacheCost: Int { return kf.cost }
+}
+
+extension Data: DataTransformable {
+    public func toData() throws -> Data {
+        return self
+    }
+
+    public static func fromData(_ data: Data) throws -> Data {
+        return data
+    }
+
+    public static let empty = Data()
+}
+
+
+/// Represents the getting image operation from the cache.
+///
+/// - disk: The image can be retrieved from disk cache.
+/// - memory: The image can be retrieved memory cache.
+/// - none: The image does not exist in the cache.
+public enum ImageCacheResult {
+    
+    /// The image can be retrieved from disk cache.
+    case disk(KFCrossPlatformImage)
+    
+    /// The image can be retrieved memory cache.
+    case memory(KFCrossPlatformImage)
+    
+    /// The image does not exist in the cache.
+    case none
+    
+    /// Extracts the image from cache result. It returns the associated `Image` value for
+    /// `.disk` and `.memory` case. For `.none` case, `nil` is returned.
+    public var image: KFCrossPlatformImage? {
+        switch self {
+        case .disk(let image): return image
+        case .memory(let image): return image
+        case .none: return nil
+        }
+    }
+    
+    /// Returns the corresponding `CacheType` value based on the result type of `self`.
+    public var cacheType: CacheType {
+        switch self {
+        case .disk: return .disk
+        case .memory: return .memory
+        case .none: return .none
+        }
+    }
+}
+
+/// Represents a hybrid caching system which is composed by a `MemoryStorage.Backend` and a `DiskStorage.Backend`.
+/// `ImageCache` is a high level abstract for storing an image as well as its data to memory and disk, and
+/// retrieving them back.
+///
+/// While a default image cache object will be used if you prefer the extension methods of Kingfisher, you can create
+/// your own cache object and configure its storages as your need. This class also provide an interface for you to set
+/// the memory and disk storage config.
+open class ImageCache {
+
+    // MARK: Singleton
+    /// The default `ImageCache` object. Kingfisher will use this cache for its related methods if there is no
+    /// other cache specified. The `name` of this default cache is "default", and you should not use this name
+    /// for any of your customize cache.
+    public static let `default` = ImageCache(name: "default")
+
+
+    // MARK: Public Properties
+    /// The `MemoryStorage.Backend` object used in this cache. This storage holds loaded images in memory with a
+    /// reasonable expire duration and a maximum memory usage. To modify the configuration of a storage, just set
+    /// the storage `config` and its properties.
+    public let memoryStorage: MemoryStorage.Backend<KFCrossPlatformImage>
+    
+    /// The `DiskStorage.Backend` object used in this cache. This storage stores loaded images in disk with a
+    /// reasonable expire duration and a maximum disk usage. To modify the configuration of a storage, just set
+    /// the storage `config` and its properties.
+    public let diskStorage: DiskStorage.Backend<Data>
+    
+    private let ioQueue: DispatchQueue
+    
+    /// Closure that defines the disk cache path from a given path and cacheName.
+    public typealias DiskCachePathClosure = (URL, String) -> URL
+
+    // MARK: Initializers
+
+    /// Creates an `ImageCache` from a customized `MemoryStorage` and `DiskStorage`.
+    ///
+    /// - Parameters:
+    ///   - memoryStorage: The `MemoryStorage.Backend` object to use in the image cache.
+    ///   - diskStorage: The `DiskStorage.Backend` object to use in the image cache.
+    public init(
+        memoryStorage: MemoryStorage.Backend<KFCrossPlatformImage>,
+        diskStorage: DiskStorage.Backend<Data>)
+    {
+        self.memoryStorage = memoryStorage
+        self.diskStorage = diskStorage
+        let ioQueueName = "com.onevcat.Kingfisher.ImageCache.ioQueue.\(UUID().uuidString)"
+        ioQueue = DispatchQueue(label: ioQueueName)
+
+        let notifications: [(Notification.Name, Selector)]
+        #if !os(macOS) && !os(watchOS)
+        notifications = [
+            (UIApplication.didReceiveMemoryWarningNotification, #selector(clearMemoryCache)),
+            (UIApplication.willTerminateNotification, #selector(cleanExpiredDiskCache)),
+            (UIApplication.didEnterBackgroundNotification, #selector(backgroundCleanExpiredDiskCache))
+        ]
+        #elseif os(macOS)
+        notifications = [
+            (NSApplication.willResignActiveNotification, #selector(cleanExpiredDiskCache)),
+        ]
+        #else
+        notifications = []
+        #endif
+        notifications.forEach {
+            NotificationCenter.default.addObserver(self, selector: $0.1, name: $0.0, object: nil)
+        }
+    }
+    
+    /// Creates an `ImageCache` with a given `name`. Both `MemoryStorage` and `DiskStorage` will be created
+    /// with a default config based on the `name`.
+    ///
+    /// - Parameter name: The name of cache object. It is used to setup disk cache directories and IO queue.
+    ///                   You should not use the same `name` for different caches, otherwise, the disk storage would
+    ///                   be conflicting to each other. The `name` should not be an empty string.
+    public convenience init(name: String) {
+        self.init(noThrowName: name, cacheDirectoryURL: nil, diskCachePathClosure: nil)
+    }
+
+    /// Creates an `ImageCache` with a given `name`, cache directory `path`
+    /// and a closure to modify the cache directory.
+    ///
+    /// - Parameters:
+    ///   - name: The name of cache object. It is used to setup disk cache directories and IO queue.
+    ///           You should not use the same `name` for different caches, otherwise, the disk storage would
+    ///           be conflicting to each other.
+    ///   - cacheDirectoryURL: Location of cache directory URL on disk. It will be internally pass to the
+    ///                        initializer of `DiskStorage` as the disk cache directory. If `nil`, the cache
+    ///                        directory under user domain mask will be used.
+    ///   - diskCachePathClosure: Closure that takes in an optional initial path string and generates
+    ///                           the final disk cache path. You could use it to fully customize your cache path.
+    /// - Throws: An error that happens during image cache creating, such as unable to create a directory at the given
+    ///           path.
+    public convenience init(
+        name: String,
+        cacheDirectoryURL: URL?,
+        diskCachePathClosure: DiskCachePathClosure? = nil
+    ) throws
+    {
+        if name.isEmpty {
+            fatalError("[Kingfisher] You should specify a name for the cache. A cache with empty name is not permitted.")
+        }
+
+        let memoryStorage = ImageCache.createMemoryStorage()
+
+        let config = ImageCache.createConfig(
+            name: name, cacheDirectoryURL: cacheDirectoryURL, diskCachePathClosure: diskCachePathClosure
+        )
+        let diskStorage = try DiskStorage.Backend<Data>(config: config)
+        self.init(memoryStorage: memoryStorage, diskStorage: diskStorage)
+    }
+
+    convenience init(
+        noThrowName name: String,
+        cacheDirectoryURL: URL?,
+        diskCachePathClosure: DiskCachePathClosure?
+    )
+    {
+        if name.isEmpty {
+            fatalError("[Kingfisher] You should specify a name for the cache. A cache with empty name is not permitted.")
+        }
+
+        let memoryStorage = ImageCache.createMemoryStorage()
+
+        let config = ImageCache.createConfig(
+            name: name, cacheDirectoryURL: cacheDirectoryURL, diskCachePathClosure: diskCachePathClosure
+        )
+        let diskStorage = DiskStorage.Backend<Data>(noThrowConfig: config, creatingDirectory: true)
+        self.init(memoryStorage: memoryStorage, diskStorage: diskStorage)
+    }
+
+    private static func createMemoryStorage() -> MemoryStorage.Backend<KFCrossPlatformImage> {
+        let totalMemory = ProcessInfo.processInfo.physicalMemory
+        let costLimit = totalMemory / 4
+        let memoryStorage = MemoryStorage.Backend<KFCrossPlatformImage>(config:
+            .init(totalCostLimit: (costLimit > Int.max) ? Int.max : Int(costLimit)))
+        return memoryStorage
+    }
+
+    private static func createConfig(
+        name: String,
+        cacheDirectoryURL: URL?,
+        diskCachePathClosure: DiskCachePathClosure? = nil
+    ) -> DiskStorage.Config
+    {
+        var diskConfig = DiskStorage.Config(
+            name: name,
+            sizeLimit: 0,
+            directory: cacheDirectoryURL
+        )
+        if let closure = diskCachePathClosure {
+            diskConfig.cachePathBlock = closure
+        }
+        return diskConfig
+    }
+    
+    deinit {
+        NotificationCenter.default.removeObserver(self)
+    }
+
+    // MARK: Storing Images
+
+    open func store(_ image: KFCrossPlatformImage,
+                    original: Data? = nil,
+                    forKey key: String,
+                    options: KingfisherParsedOptionsInfo,
+                    toDisk: Bool = true,
+                    completionHandler: ((CacheStoreResult) -> Void)? = nil)
+    {
+        let identifier = options.processor.identifier
+        let callbackQueue = options.callbackQueue
+        
+        let computedKey = key.computedKey(with: identifier)
+        // Memory storage should not throw.
+        memoryStorage.storeNoThrow(value: image, forKey: computedKey, expiration: options.memoryCacheExpiration)
+        
+        guard toDisk else {
+            if let completionHandler = completionHandler {
+                let result = CacheStoreResult(memoryCacheResult: .success(()), diskCacheResult: .success(()))
+                callbackQueue.execute { completionHandler(result) }
+            }
+            return
+        }
+        
+        ioQueue.async {
+            let serializer = options.cacheSerializer
+            if let data = serializer.data(with: image, original: original) {
+                self.syncStoreToDisk(
+                    data,
+                    forKey: key,
+                    processorIdentifier: identifier,
+                    callbackQueue: callbackQueue,
+                    expiration: options.diskCacheExpiration,
+                    writeOptions: options.diskStoreWriteOptions,
+                    completionHandler: completionHandler)
+            } else {
+                guard let completionHandler = completionHandler else { return }
+                
+                let diskError = KingfisherError.cacheError(
+                    reason: .cannotSerializeImage(image: image, original: original, serializer: serializer))
+                let result = CacheStoreResult(
+                    memoryCacheResult: .success(()),
+                    diskCacheResult: .failure(diskError))
+                callbackQueue.execute { completionHandler(result) }
+            }
+        }
+    }
+
+    /// Stores an image to the cache.
+    ///
+    /// - Parameters:
+    ///   - image: The image to be stored.
+    ///   - original: The original data of the image. This value will be forwarded to the provided `serializer` for
+    ///               further use. By default, Kingfisher uses a `DefaultCacheSerializer` to serialize the image to
+    ///               data for caching in disk, it checks the image format based on `original` data to determine in
+    ///               which image format should be used. For other types of `serializer`, it depends on their
+    ///               implementation detail on how to use this original data.
+    ///   - key: The key used for caching the image.
+    ///   - identifier: The identifier of processor being used for caching. If you are using a processor for the
+    ///                 image, pass the identifier of processor to this parameter.
+    ///   - serializer: The `CacheSerializer`
+    ///   - toDisk: Whether this image should be cached to disk or not. If `false`, the image is only cached in memory.
+    ///             Otherwise, it is cached in both memory storage and disk storage. Default is `true`.
+    ///   - callbackQueue: The callback queue on which `completionHandler` is invoked. Default is `.untouch`. For case
+    ///                    that `toDisk` is `false`, a `.untouch` queue means `callbackQueue` will be invoked from the
+    ///                    caller queue of this method. If `toDisk` is `true`, the `completionHandler` will be called
+    ///                    from an internal file IO queue. To change this behavior, specify another `CallbackQueue`
+    ///                    value.
+    ///   - completionHandler: A closure which is invoked when the cache operation finishes.
+    open func store(_ image: KFCrossPlatformImage,
+                      original: Data? = nil,
+                      forKey key: String,
+                      processorIdentifier identifier: String = "",
+                      cacheSerializer serializer: CacheSerializer = DefaultCacheSerializer.default,
+                      toDisk: Bool = true,
+                      callbackQueue: CallbackQueue = .untouch,
+                      completionHandler: ((CacheStoreResult) -> Void)? = nil)
+    {
+        struct TempProcessor: ImageProcessor {
+            let identifier: String
+            func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+                return nil
+            }
+        }
+        
+        let options = KingfisherParsedOptionsInfo([
+            .processor(TempProcessor(identifier: identifier)),
+            .cacheSerializer(serializer),
+            .callbackQueue(callbackQueue)
+        ])
+        store(image, original: original, forKey: key, options: options,
+              toDisk: toDisk, completionHandler: completionHandler)
+    }
+    
+    open func storeToDisk(
+        _ data: Data,
+        forKey key: String,
+        processorIdentifier identifier: String = "",
+        expiration: StorageExpiration? = nil,
+        callbackQueue: CallbackQueue = .untouch,
+        completionHandler: ((CacheStoreResult) -> Void)? = nil)
+    {
+        ioQueue.async {
+            self.syncStoreToDisk(
+                data,
+                forKey: key,
+                processorIdentifier: identifier,
+                callbackQueue: callbackQueue,
+                expiration: expiration,
+                completionHandler: completionHandler)
+        }
+    }
+    
+    private func syncStoreToDisk(
+        _ data: Data,
+        forKey key: String,
+        processorIdentifier identifier: String = "",
+        callbackQueue: CallbackQueue = .untouch,
+        expiration: StorageExpiration? = nil,
+        writeOptions: Data.WritingOptions = [],
+        completionHandler: ((CacheStoreResult) -> Void)? = nil)
+    {
+        let computedKey = key.computedKey(with: identifier)
+        let result: CacheStoreResult
+        do {
+            try self.diskStorage.store(value: data, forKey: computedKey, expiration: expiration, writeOptions: writeOptions)
+            result = CacheStoreResult(memoryCacheResult: .success(()), diskCacheResult: .success(()))
+        } catch {
+            let diskError: KingfisherError
+            if let error = error as? KingfisherError {
+                diskError = error
+            } else {
+                diskError = .cacheError(reason: .cannotConvertToData(object: data, error: error))
+            }
+            
+            result = CacheStoreResult(
+                memoryCacheResult: .success(()),
+                diskCacheResult: .failure(diskError)
+            )
+        }
+        if let completionHandler = completionHandler {
+            callbackQueue.execute { completionHandler(result) }
+        }
+    }
+
+    // MARK: Removing Images
+
+    /// Removes the image for the given key from the cache.
+    ///
+    /// - Parameters:
+    ///   - key: The key used for caching the image.
+    ///   - identifier: The identifier of processor being used for caching. If you are using a processor for the
+    ///                 image, pass the identifier of processor to this parameter.
+    ///   - fromMemory: Whether this image should be removed from memory storage or not.
+    ///                 If `false`, the image won't be removed from the memory storage. Default is `true`.
+    ///   - fromDisk: Whether this image should be removed from disk storage or not.
+    ///               If `false`, the image won't be removed from the disk storage. Default is `true`.
+    ///   - callbackQueue: The callback queue on which `completionHandler` is invoked. Default is `.untouch`.
+    ///   - completionHandler: A closure which is invoked when the cache removing operation finishes.
+    open func removeImage(forKey key: String,
+                          processorIdentifier identifier: String = "",
+                          fromMemory: Bool = true,
+                          fromDisk: Bool = true,
+                          callbackQueue: CallbackQueue = .untouch,
+                          completionHandler: (() -> Void)? = nil)
+    {
+        let computedKey = key.computedKey(with: identifier)
+
+        if fromMemory {
+            memoryStorage.remove(forKey: computedKey)
+        }
+        
+        if fromDisk {
+            ioQueue.async{
+                try? self.diskStorage.remove(forKey: computedKey)
+                if let completionHandler = completionHandler {
+                    callbackQueue.execute { completionHandler() }
+                }
+            }
+        } else {
+            if let completionHandler = completionHandler {
+                callbackQueue.execute { completionHandler() }
+            }
+        }
+    }
+
+    // MARK: Getting Images
+
+    /// Gets an image for a given key from the cache, either from memory storage or disk storage.
+    ///
+    /// - Parameters:
+    ///   - key: The key used for caching the image.
+    ///   - options: The `KingfisherParsedOptionsInfo` options setting used for retrieving the image.
+    ///   - callbackQueue: The callback queue on which `completionHandler` is invoked. Default is `.mainCurrentOrAsync`.
+    ///   - completionHandler: A closure which is invoked when the image getting operation finishes. If the
+    ///                        image retrieving operation finishes without problem, an `ImageCacheResult` value
+    ///                        will be sent to this closure as result. Otherwise, a `KingfisherError` result
+    ///                        with detail failing reason will be sent.
+    open func retrieveImage(
+        forKey key: String,
+        options: KingfisherParsedOptionsInfo,
+        callbackQueue: CallbackQueue = .mainCurrentOrAsync,
+        completionHandler: ((Result<ImageCacheResult, KingfisherError>) -> Void)?)
+    {
+        // No completion handler. No need to start working and early return.
+        guard let completionHandler = completionHandler else { return }
+
+        // Try to check the image from memory cache first.
+        if let image = retrieveImageInMemoryCache(forKey: key, options: options) {
+            callbackQueue.execute { completionHandler(.success(.memory(image))) }
+        } else if options.fromMemoryCacheOrRefresh {
+            callbackQueue.execute { completionHandler(.success(.none)) }
+        } else {
+
+            // Begin to disk search.
+            self.retrieveImageInDiskCache(forKey: key, options: options, callbackQueue: callbackQueue) {
+                result in
+                switch result {
+                case .success(let image):
+
+                    guard let image = image else {
+                        // No image found in disk storage.
+                        callbackQueue.execute { completionHandler(.success(.none)) }
+                        return
+                    }
+
+                    // Cache the disk image to memory.
+                    // We are passing `false` to `toDisk`, the memory cache does not change
+                    // callback queue, we can call `completionHandler` without another dispatch.
+                    var cacheOptions = options
+                    cacheOptions.callbackQueue = .untouch
+                    self.store(
+                        image,
+                        forKey: key,
+                        options: cacheOptions,
+                        toDisk: false)
+                    {
+                        _ in
+                        callbackQueue.execute { completionHandler(.success(.disk(image))) }
+                    }
+                case .failure(let error):
+                    callbackQueue.execute { completionHandler(.failure(error)) }
+                }
+            }
+        }
+    }
+
+    /// Gets an image for a given key from the cache, either from memory storage or disk storage.
+    ///
+    /// - Parameters:
+    ///   - key: The key used for caching the image.
+    ///   - options: The `KingfisherOptionsInfo` options setting used for retrieving the image.
+    ///   - callbackQueue: The callback queue on which `completionHandler` is invoked. Default is `.mainCurrentOrAsync`.
+    ///   - completionHandler: A closure which is invoked when the image getting operation finishes. If the
+    ///                        image retrieving operation finishes without problem, an `ImageCacheResult` value
+    ///                        will be sent to this closure as result. Otherwise, a `KingfisherError` result
+    ///                        with detail failing reason will be sent.
+    ///
+    /// Note: This method is marked as `open` for only compatible purpose. Do not overide this method. Instead, override
+    ///       the version receives `KingfisherParsedOptionsInfo` instead.
+    open func retrieveImage(forKey key: String,
+                               options: KingfisherOptionsInfo? = nil,
+                        callbackQueue: CallbackQueue = .mainCurrentOrAsync,
+                     completionHandler: ((Result<ImageCacheResult, KingfisherError>) -> Void)?)
+    {
+        retrieveImage(
+            forKey: key,
+            options: KingfisherParsedOptionsInfo(options),
+            callbackQueue: callbackQueue,
+            completionHandler: completionHandler)
+    }
+
+    /// Gets an image for a given key from the memory storage.
+    ///
+    /// - Parameters:
+    ///   - key: The key used for caching the image.
+    ///   - options: The `KingfisherParsedOptionsInfo` options setting used for retrieving the image.
+    /// - Returns: The image stored in memory cache, if exists and valid. Otherwise, if the image does not exist or
+    ///            has already expired, `nil` is returned.
+    open func retrieveImageInMemoryCache(
+        forKey key: String,
+        options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage?
+    {
+        let computedKey = key.computedKey(with: options.processor.identifier)
+        return memoryStorage.value(forKey: computedKey, extendingExpiration: options.memoryCacheAccessExtendingExpiration)
+    }
+
+    /// Gets an image for a given key from the memory storage.
+    ///
+    /// - Parameters:
+    ///   - key: The key used for caching the image.
+    ///   - options: The `KingfisherOptionsInfo` options setting used for retrieving the image.
+    /// - Returns: The image stored in memory cache, if exists and valid. Otherwise, if the image does not exist or
+    ///            has already expired, `nil` is returned.
+    ///
+    /// Note: This method is marked as `open` for only compatible purpose. Do not overide this method. Instead, override
+    ///       the version receives `KingfisherParsedOptionsInfo` instead.
+    open func retrieveImageInMemoryCache(
+        forKey key: String,
+        options: KingfisherOptionsInfo? = nil) -> KFCrossPlatformImage?
+    {
+        return retrieveImageInMemoryCache(forKey: key, options: KingfisherParsedOptionsInfo(options))
+    }
+
+    func retrieveImageInDiskCache(
+        forKey key: String,
+        options: KingfisherParsedOptionsInfo,
+        callbackQueue: CallbackQueue = .untouch,
+        completionHandler: @escaping (Result<KFCrossPlatformImage?, KingfisherError>) -> Void)
+    {
+        let computedKey = key.computedKey(with: options.processor.identifier)
+        let loadingQueue: CallbackQueue = options.loadDiskFileSynchronously ? .untouch : .dispatch(ioQueue)
+        loadingQueue.execute {
+            do {
+                var image: KFCrossPlatformImage? = nil
+                if let data = try self.diskStorage.value(forKey: computedKey, extendingExpiration: options.diskCacheAccessExtendingExpiration) {
+                    image = options.cacheSerializer.image(with: data, options: options)
+                }
+                if options.backgroundDecode {
+                    image = image?.kf.decoded(scale: options.scaleFactor)
+                }
+                callbackQueue.execute { completionHandler(.success(image)) }
+            } catch let error as KingfisherError {
+                callbackQueue.execute { completionHandler(.failure(error)) }
+            } catch {
+                assertionFailure("The internal thrown error should be a `KingfisherError`.")
+            }
+        }
+    }
+    
+    /// Gets an image for a given key from the disk storage.
+    ///
+    /// - Parameters:
+    ///   - key: The key used for caching the image.
+    ///   - options: The `KingfisherOptionsInfo` options setting used for retrieving the image.
+    ///   - callbackQueue: The callback queue on which `completionHandler` is invoked. Default is `.untouch`.
+    ///   - completionHandler: A closure which is invoked when the operation finishes.
+    open func retrieveImageInDiskCache(
+        forKey key: String,
+        options: KingfisherOptionsInfo? = nil,
+        callbackQueue: CallbackQueue = .untouch,
+        completionHandler: @escaping (Result<KFCrossPlatformImage?, KingfisherError>) -> Void)
+    {
+        retrieveImageInDiskCache(
+            forKey: key,
+            options: KingfisherParsedOptionsInfo(options),
+            callbackQueue: callbackQueue,
+            completionHandler: completionHandler)
+    }
+
+    // MARK: Cleaning
+    /// Clears the memory & disk storage of this cache. This is an async operation.
+    ///
+    /// - Parameter handler: A closure which is invoked when the cache clearing operation finishes.
+    ///                      This `handler` will be called from the main queue.
+    public func clearCache(completion handler: (() -> Void)? = nil) {
+        clearMemoryCache()
+        clearDiskCache(completion: handler)
+    }
+    
+    /// Clears the memory storage of this cache.
+    @objc public func clearMemoryCache() {
+        memoryStorage.removeAll()
+    }
+    
+    /// Clears the disk storage of this cache. This is an async operation.
+    ///
+    /// - Parameter handler: A closure which is invoked when the cache clearing operation finishes.
+    ///                      This `handler` will be called from the main queue.
+    open func clearDiskCache(completion handler: (() -> Void)? = nil) {
+        ioQueue.async {
+            do {
+                try self.diskStorage.removeAll()
+            } catch _ { }
+            if let handler = handler {
+                DispatchQueue.main.async { handler() }
+            }
+        }
+    }
+    
+    /// Clears the expired images from memory & disk storage. This is an async operation.
+    open func cleanExpiredCache(completion handler: (() -> Void)? = nil) {
+        cleanExpiredMemoryCache()
+        cleanExpiredDiskCache(completion: handler)
+    }
+
+    /// Clears the expired images from disk storage.
+    open func cleanExpiredMemoryCache() {
+        memoryStorage.removeExpired()
+    }
+    
+    /// Clears the expired images from disk storage. This is an async operation.
+    @objc func cleanExpiredDiskCache() {
+        cleanExpiredDiskCache(completion: nil)
+    }
+
+    /// Clears the expired images from disk storage. This is an async operation.
+    ///
+    /// - Parameter handler: A closure which is invoked when the cache clearing operation finishes.
+    ///                      This `handler` will be called from the main queue.
+    open func cleanExpiredDiskCache(completion handler: (() -> Void)? = nil) {
+        ioQueue.async {
+            do {
+                var removed: [URL] = []
+                let removedExpired = try self.diskStorage.removeExpiredValues()
+                removed.append(contentsOf: removedExpired)
+
+                let removedSizeExceeded = try self.diskStorage.removeSizeExceededValues()
+                removed.append(contentsOf: removedSizeExceeded)
+
+                if !removed.isEmpty {
+                    DispatchQueue.main.async {
+                        let cleanedHashes = removed.map { $0.lastPathComponent }
+                        NotificationCenter.default.post(
+                            name: .KingfisherDidCleanDiskCache,
+                            object: self,
+                            userInfo: [KingfisherDiskCacheCleanedHashKey: cleanedHashes])
+                    }
+                }
+
+                if let handler = handler {
+                    DispatchQueue.main.async { handler() }
+                }
+            } catch {}
+        }
+    }
+
+#if !os(macOS) && !os(watchOS)
+    /// Clears the expired images from disk storage when app is in background. This is an async operation.
+    /// In most cases, you should not call this method explicitly.
+    /// It will be called automatically when `UIApplicationDidEnterBackgroundNotification` received.
+    @objc public func backgroundCleanExpiredDiskCache() {
+        // if 'sharedApplication()' is unavailable, then return
+        guard let sharedApplication = KingfisherWrapper<UIApplication>.shared else { return }
+
+        func endBackgroundTask(_ task: inout UIBackgroundTaskIdentifier) {
+            sharedApplication.endBackgroundTask(task)
+            task = UIBackgroundTaskIdentifier.invalid
+        }
+        
+        var backgroundTask: UIBackgroundTaskIdentifier!
+        backgroundTask = sharedApplication.beginBackgroundTask {
+            endBackgroundTask(&backgroundTask!)
+        }
+        
+        cleanExpiredDiskCache {
+            endBackgroundTask(&backgroundTask!)
+        }
+    }
+#endif
+
+    // MARK: Image Cache State
+
+    /// Returns the cache type for a given `key` and `identifier` combination.
+    /// This method is used for checking whether an image is cached in current cache.
+    /// It also provides information on which kind of cache can it be found in the return value.
+    ///
+    /// - Parameters:
+    ///   - key: The key used for caching the image.
+    ///   - identifier: Processor identifier which used for this image. Default is the `identifier` of
+    ///                 `DefaultImageProcessor.default`.
+    /// - Returns: A `CacheType` instance which indicates the cache status.
+    ///            `.none` means the image is not in cache or it is already expired.
+    open func imageCachedType(
+        forKey key: String,
+        processorIdentifier identifier: String = DefaultImageProcessor.default.identifier) -> CacheType
+    {
+        let computedKey = key.computedKey(with: identifier)
+        if memoryStorage.isCached(forKey: computedKey) { return .memory }
+        if diskStorage.isCached(forKey: computedKey) { return .disk }
+        return .none
+    }
+    
+    /// Returns whether the file exists in cache for a given `key` and `identifier` combination.
+    ///
+    /// - Parameters:
+    ///   - key: The key used for caching the image.
+    ///   - identifier: Processor identifier which used for this image. Default is the `identifier` of
+    ///                 `DefaultImageProcessor.default`.
+    /// - Returns: A `Bool` which indicates whether a cache could match the given `key` and `identifier` combination.
+    ///
+    /// - Note:
+    /// The return value does not contain information about from which kind of storage the cache matches.
+    /// To get the information about cache type according `CacheType`,
+    /// use `imageCachedType(forKey:processorIdentifier:)` instead.
+    public func isCached(
+        forKey key: String,
+        processorIdentifier identifier: String = DefaultImageProcessor.default.identifier) -> Bool
+    {
+        return imageCachedType(forKey: key, processorIdentifier: identifier).cached
+    }
+    
+    /// Gets the hash used as cache file name for the key.
+    ///
+    /// - Parameters:
+    ///   - key: The key used for caching the image.
+    ///   - identifier: Processor identifier which used for this image. Default is the `identifier` of
+    ///                 `DefaultImageProcessor.default`.
+    /// - Returns: The hash which is used as the cache file name.
+    ///
+    /// - Note:
+    /// By default, for a given combination of `key` and `identifier`, `ImageCache` will use the value
+    /// returned by this method as the cache file name. You can use this value to check and match cache file
+    /// if you need.
+    open func hash(
+        forKey key: String,
+        processorIdentifier identifier: String = DefaultImageProcessor.default.identifier) -> String
+    {
+        let computedKey = key.computedKey(with: identifier)
+        return diskStorage.cacheFileName(forKey: computedKey)
+    }
+    
+    /// Calculates the size taken by the disk storage.
+    /// It is the total file size of all cached files in the `diskStorage` on disk in bytes.
+    ///
+    /// - Parameter handler: Called with the size calculating finishes. This closure is invoked from the main queue.
+    open func calculateDiskStorageSize(completion handler: @escaping ((Result<UInt, KingfisherError>) -> Void)) {
+        ioQueue.async {
+            do {
+                let size = try self.diskStorage.totalSize()
+                DispatchQueue.main.async { handler(.success(size)) }
+            } catch let error as KingfisherError {
+                DispatchQueue.main.async { handler(.failure(error)) }
+            } catch {
+                assertionFailure("The internal thrown error should be a `KingfisherError`.")
+            }
+        }
+    }
+    
+    #if swift(>=5.5)
+    #if canImport(_Concurrency)
+    @available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
+    open var diskStorageSize: UInt {
+        get async throws {
+            try await withCheckedThrowingContinuation { continuation in
+                calculateDiskStorageSize { result in
+                    continuation.resume(with: result)
+                }
+            }
+        }
+    }
+    #endif
+    #endif
+    
+    /// Gets the cache path for the key.
+    /// It is useful for projects with web view or anyone that needs access to the local file path.
+    ///
+    /// i.e. Replacing the `<img src='path_for_key'>` tag in your HTML.
+    ///
+    /// - Parameters:
+    ///   - key: The key used for caching the image.
+    ///   - identifier: Processor identifier which used for this image. Default is the `identifier` of
+    ///                 `DefaultImageProcessor.default`.
+    /// - Returns: The disk path of cached image under the given `key` and `identifier`.
+    ///
+    /// - Note:
+    /// This method does not guarantee there is an image already cached in the returned path. It just gives your
+    /// the path that the image should be, if it exists in disk storage.
+    ///
+    /// You could use `isCached(forKey:)` method to check whether the image is cached under that key in disk.
+    open func cachePath(
+        forKey key: String,
+        processorIdentifier identifier: String = DefaultImageProcessor.default.identifier) -> String
+    {
+        let computedKey = key.computedKey(with: identifier)
+        return diskStorage.cacheFileURL(forKey: computedKey).path
+    }
+}
+
+#if !os(macOS) && !os(watchOS)
+// MARK: - For App Extensions
+extension UIApplication: KingfisherCompatible { }
+extension KingfisherWrapper where Base: UIApplication {
+    public static var shared: UIApplication? {
+        let selector = NSSelectorFromString("sharedApplication")
+        guard Base.responds(to: selector) else { return nil }
+        return Base.perform(selector).takeUnretainedValue() as? UIApplication
+    }
+}
+#endif
+
+extension String {
+    func computedKey(with identifier: String) -> String {
+        if identifier.isEmpty {
+            return self
+        } else {
+            return appending("@\(identifier)")
+        }
+    }
+}

Pods/Kingfisher/Sources/Cache/MemoryStorage.swift

@@ -0,0 +1,283 @@
+//
+//  MemoryStorage.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2018/10/15.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+/// Represents a set of conception related to storage which stores a certain type of value in memory.
+/// This is a namespace for the memory storage types. A `Backend` with a certain `Config` will be used to describe the
+/// storage. See these composed types for more information.
+public enum MemoryStorage {
+
+    /// Represents a storage which stores a certain type of value in memory. It provides fast access,
+    /// but limited storing size. The stored value type needs to conform to `CacheCostCalculable`,
+    /// and its `cacheCost` will be used to determine the cost of size for the cache item.
+    ///
+    /// You can config a `MemoryStorage.Backend` in its initializer by passing a `MemoryStorage.Config` value.
+    /// or modifying the `config` property after it being created. The backend of `MemoryStorage` has
+    /// upper limitation on cost size in memory and item count. All items in the storage has an expiration
+    /// date. When retrieved, if the target item is already expired, it will be recognized as it does not
+    /// exist in the storage. The `MemoryStorage` also contains a scheduled self clean task, to evict expired
+    /// items from memory.
+    public class Backend<T: CacheCostCalculable> {
+        let storage = NSCache<NSString, StorageObject<T>>()
+
+        // Keys trackes the objects once inside the storage. For object removing triggered by user, the corresponding
+        // key would be also removed. However, for the object removing triggered by cache rule/policy of system, the
+        // key will be remained there until next `removeExpired` happens.
+        //
+        // Breaking the strict tracking could save additional locking behaviors.
+        // See https://github.com/onevcat/Kingfisher/issues/1233
+        var keys = Set<String>()
+
+        private var cleanTimer: Timer? = nil
+        private let lock = NSLock()
+
+        /// The config used in this storage. It is a value you can set and
+        /// use to config the storage in air.
+        public var config: Config {
+            didSet {
+                storage.totalCostLimit = config.totalCostLimit
+                storage.countLimit = config.countLimit
+            }
+        }
+
+        /// Creates a `MemoryStorage` with a given `config`.
+        ///
+        /// - Parameter config: The config used to create the storage. It determines the max size limitation,
+        ///                     default expiration setting and more.
+        public init(config: Config) {
+            self.config = config
+            storage.totalCostLimit = config.totalCostLimit
+            storage.countLimit = config.countLimit
+
+            cleanTimer = .scheduledTimer(withTimeInterval: config.cleanInterval, repeats: true) { [weak self] _ in
+                guard let self = self else { return }
+                self.removeExpired()
+            }
+        }
+
+        /// Removes the expired values from the storage.
+        public func removeExpired() {
+            lock.lock()
+            defer { lock.unlock() }
+            for key in keys {
+                let nsKey = key as NSString
+                guard let object = storage.object(forKey: nsKey) else {
+                    // This could happen if the object is moved by cache `totalCostLimit` or `countLimit` rule.
+                    // We didn't remove the key yet until now, since we do not want to introduce additional lock.
+                    // See https://github.com/onevcat/Kingfisher/issues/1233
+                    keys.remove(key)
+                    continue
+                }
+                if object.isExpired {
+                    storage.removeObject(forKey: nsKey)
+                    keys.remove(key)
+                }
+            }
+        }
+
+        /// Stores a value to the storage under the specified key and expiration policy.
+        /// - Parameters:
+        ///   - value: The value to be stored.
+        ///   - key: The key to which the `value` will be stored.
+        ///   - expiration: The expiration policy used by this store action.
+        /// - Throws: No error will
+        public func store(
+            value: T,
+            forKey key: String,
+            expiration: StorageExpiration? = nil)
+        {
+            storeNoThrow(value: value, forKey: key, expiration: expiration)
+        }
+
+        // The no throw version for storing value in cache. Kingfisher knows the detail so it
+        // could use this version to make syntax simpler internally.
+        func storeNoThrow(
+            value: T,
+            forKey key: String,
+            expiration: StorageExpiration? = nil)
+        {
+            lock.lock()
+            defer { lock.unlock() }
+            let expiration = expiration ?? config.expiration
+            // The expiration indicates that already expired, no need to store.
+            guard !expiration.isExpired else { return }
+            
+            let object: StorageObject<T>
+            if config.keepWhenEnteringBackground {
+                object = BackgroundKeepingStorageObject(value, expiration: expiration)
+            } else {
+                object = StorageObject(value, expiration: expiration)
+            }
+            storage.setObject(object, forKey: key as NSString, cost: value.cacheCost)
+            keys.insert(key)
+        }
+        
+        /// Gets a value from the storage.
+        ///
+        /// - Parameters:
+        ///   - key: The cache key of value.
+        ///   - extendingExpiration: The expiration policy used by this getting action.
+        /// - Returns: The value under `key` if it is valid and found in the storage. Otherwise, `nil`.
+        public func value(forKey key: String, extendingExpiration: ExpirationExtending = .cacheTime) -> T? {
+            guard let object = storage.object(forKey: key as NSString) else {
+                return nil
+            }
+            if object.isExpired {
+                return nil
+            }
+            object.extendExpiration(extendingExpiration)
+            return object.value
+        }
+
+        /// Whether there is valid cached data under a given key.
+        /// - Parameter key: The cache key of value.
+        /// - Returns: If there is valid data under the key, `true`. Otherwise, `false`.
+        public func isCached(forKey key: String) -> Bool {
+            guard let _ = value(forKey: key, extendingExpiration: .none) else {
+                return false
+            }
+            return true
+        }
+
+        /// Removes a value from a specified key.
+        /// - Parameter key: The cache key of value.
+        public func remove(forKey key: String) {
+            lock.lock()
+            defer { lock.unlock() }
+            storage.removeObject(forKey: key as NSString)
+            keys.remove(key)
+        }
+
+        /// Removes all values in this storage.
+        public func removeAll() {
+            lock.lock()
+            defer { lock.unlock() }
+            storage.removeAllObjects()
+            keys.removeAll()
+        }
+    }
+}
+
+extension MemoryStorage {
+    /// Represents the config used in a `MemoryStorage`.
+    public struct Config {
+
+        /// Total cost limit of the storage in bytes.
+        public var totalCostLimit: Int
+
+        /// The item count limit of the memory storage.
+        public var countLimit: Int = .max
+
+        /// The `StorageExpiration` used in this memory storage. Default is `.seconds(300)`,
+        /// means that the memory cache would expire in 5 minutes.
+        public var expiration: StorageExpiration = .seconds(300)
+
+        /// The time interval between the storage do clean work for swiping expired items.
+        public var cleanInterval: TimeInterval
+        
+        /// Whether the newly added items to memory cache should be purged when the app goes to background.
+        ///
+        /// By default, the cached items in memory will be purged as soon as the app goes to background to ensure
+        /// least memory footprint. Enabling this would prevent this behavior and keep the items alive in cache even
+        /// when your app is not in foreground anymore.
+        ///
+        /// Default is `false`. After setting `true`, only the newly added cache objects are affected. Existing
+        /// objects which are already in the cache while this value was `false` will be still be purged when entering
+        /// background.
+        public var keepWhenEnteringBackground: Bool = false
+
+        /// Creates a config from a given `totalCostLimit` value.
+        ///
+        /// - Parameters:
+        ///   - totalCostLimit: Total cost limit of the storage in bytes.
+        ///   - cleanInterval: The time interval between the storage do clean work for swiping expired items.
+        ///                    Default is 120, means the auto eviction happens once per two minutes.
+        ///
+        /// - Note:
+        /// Other members of `MemoryStorage.Config` will use their default values when created.
+        public init(totalCostLimit: Int, cleanInterval: TimeInterval = 120) {
+            self.totalCostLimit = totalCostLimit
+            self.cleanInterval = cleanInterval
+        }
+    }
+}
+
+extension MemoryStorage {
+    
+    class BackgroundKeepingStorageObject<T>: StorageObject<T>, NSDiscardableContent {
+        var accessing = true
+        func beginContentAccess() -> Bool {
+            if value != nil {
+                accessing = true
+            } else {
+                accessing = false
+            }
+            return accessing
+        }
+        
+        func endContentAccess() {
+            accessing = false
+        }
+        
+        func discardContentIfPossible() {
+            value = nil
+        }
+        
+        func isContentDiscarded() -> Bool {
+            return value == nil
+        }
+    }
+    
+    class StorageObject<T> {
+        var value: T?
+        let expiration: StorageExpiration
+        
+        private(set) var estimatedExpiration: Date
+        
+        init(_ value: T, expiration: StorageExpiration) {
+            self.value = value
+            self.expiration = expiration
+            
+            self.estimatedExpiration = expiration.estimatedExpirationSinceNow
+        }
+
+        func extendExpiration(_ extendingExpiration: ExpirationExtending = .cacheTime) {
+            switch extendingExpiration {
+            case .none:
+                return
+            case .cacheTime:
+                self.estimatedExpiration = expiration.estimatedExpirationSinceNow
+            case .expirationTime(let expirationTime):
+                self.estimatedExpiration = expirationTime.estimatedExpirationSinceNow
+            }
+        }
+        
+        var isExpired: Bool {
+            return estimatedExpiration.isPast
+        }
+    }
+}

Pods/Kingfisher/Sources/Cache/Storage.swift

@@ -0,0 +1,110 @@
+//
+//  Storage.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2018/10/15.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+/// Constants for some time intervals
+struct TimeConstants {
+    static let secondsInOneDay = 86_400
+}
+
+/// Represents the expiration strategy used in storage.
+///
+/// - never: The item never expires.
+/// - seconds: The item expires after a time duration of given seconds from now.
+/// - days: The item expires after a time duration of given days from now.
+/// - date: The item expires after a given date.
+public enum StorageExpiration {
+    /// The item never expires.
+    case never
+    /// The item expires after a time duration of given seconds from now.
+    case seconds(TimeInterval)
+    /// The item expires after a time duration of given days from now.
+    case days(Int)
+    /// The item expires after a given date.
+    case date(Date)
+    /// Indicates the item is already expired. Use this to skip cache.
+    case expired
+
+    func estimatedExpirationSince(_ date: Date) -> Date {
+        switch self {
+        case .never: return .distantFuture
+        case .seconds(let seconds):
+            return date.addingTimeInterval(seconds)
+        case .days(let days):
+            let duration: TimeInterval = TimeInterval(TimeConstants.secondsInOneDay) * TimeInterval(days)
+            return date.addingTimeInterval(duration)
+        case .date(let ref):
+            return ref
+        case .expired:
+            return .distantPast
+        }
+    }
+    
+    var estimatedExpirationSinceNow: Date {
+        return estimatedExpirationSince(Date())
+    }
+    
+    var isExpired: Bool {
+        return timeInterval <= 0
+    }
+
+    var timeInterval: TimeInterval {
+        switch self {
+        case .never: return .infinity
+        case .seconds(let seconds): return seconds
+        case .days(let days): return TimeInterval(TimeConstants.secondsInOneDay) * TimeInterval(days)
+        case .date(let ref): return ref.timeIntervalSinceNow
+        case .expired: return -(.infinity)
+        }
+    }
+}
+
+/// Represents the expiration extending strategy used in storage to after access.
+///
+/// - none: The item expires after the original time, without extending after access.
+/// - cacheTime: The item expiration extends by the original cache time after each access.
+/// - expirationTime: The item expiration extends by the provided time after each access.
+public enum ExpirationExtending {
+    /// The item expires after the original time, without extending after access.
+    case none
+    /// The item expiration extends by the original cache time after each access.
+    case cacheTime
+    /// The item expiration extends by the provided time after each access.
+    case expirationTime(_ expiration: StorageExpiration)
+}
+
+/// Represents types which cost in memory can be calculated.
+public protocol CacheCostCalculable {
+    var cacheCost: Int { get }
+}
+
+/// Represents types which can be converted to and from data.
+public protocol DataTransformable {
+    func toData() throws -> Data
+    static func fromData(_ data: Data) throws -> Self
+    static var empty: Self { get }
+}

Pods/Kingfisher/Sources/Extensions/CPListItem+Kingfisher.swift

@@ -0,0 +1,245 @@
+
+//
+//  CPListItem+Kingfisher.swift
+//  Kingfisher
+//
+//  Created by Wayne Hartman on 2021-08-29.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if canImport(CarPlay) && !targetEnvironment(macCatalyst)
+import CarPlay
+
+@available(iOS 14.0, *)
+extension KingfisherWrapper where Base: CPListItem {
+    
+    // MARK: Setting Image
+    
+    /// Sets an image to the image view with a source.
+    ///
+    /// - Parameters:
+    ///   - source: The `Source` object contains information about the image.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the requested source
+    /// Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with source: Source?,
+        placeholder: KFCrossPlatformImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        let options = KingfisherParsedOptionsInfo(KingfisherManager.shared.defaultOptions + (options ?? []))
+        return setImage(
+            with: source,
+            placeholder: placeholder,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler
+        )
+    }
+    
+    /// Sets an image to the image view with a requested resource.
+    ///
+    /// - Parameters:
+    ///   - resource: The `Resource` object contains information about the image.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the requested resource, from either cache
+    /// or network. Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with resource: Resource?,
+        placeholder: KFCrossPlatformImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        return setImage(
+            with: resource?.convertToSource(),
+            placeholder: placeholder,
+            options: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler)
+    }
+
+    func setImage(
+        with source: Source?,
+        placeholder: KFCrossPlatformImage? = nil,
+        parsedOptions: KingfisherParsedOptionsInfo,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        var mutatingSelf = self
+        guard let source = source else {
+            /**
+             * In iOS SDK 14.0-14.4 the image param was non-`nil`. The SDK changed in 14.5
+             * to allow `nil`. The compiler version 5.4 was introduced in this same SDK,
+             * which allows >=14.5 SDK to set a `nil` image. This compile check allows
+             * newer SDK users to set the image to `nil`, while still allowing older SDK
+             * users to compile the framework.
+             */
+            #if compiler(>=5.4)
+            self.base.setImage(placeholder)
+            #else
+            if let placeholder = placeholder {
+                self.base.setImage(placeholder)
+            }
+            #endif
+
+            mutatingSelf.taskIdentifier = nil
+            completionHandler?(.failure(KingfisherError.imageSettingError(reason: .emptySource)))
+            return nil
+        }
+        
+        var options = parsedOptions
+        if !options.keepCurrentImageWhileLoading {
+            /**
+             * In iOS SDK 14.0-14.4 the image param was non-`nil`. The SDK changed in 14.5
+             * to allow `nil`. The compiler version 5.4 was introduced in this same SDK,
+             * which allows >=14.5 SDK to set a `nil` image. This compile check allows
+             * newer SDK users to set the image to `nil`, while still allowing older SDK
+             * users to compile the framework.
+             */
+            #if compiler(>=5.4)
+            self.base.setImage(placeholder)
+            #else // Let older SDK users deal with the older behavior.
+            if let placeholder = placeholder {
+                self.base.setImage(placeholder)
+            }
+            #endif
+        }
+        
+        let issuedIdentifier = Source.Identifier.next()
+        mutatingSelf.taskIdentifier = issuedIdentifier
+        
+        if let block = progressBlock {
+            options.onDataReceived = (options.onDataReceived ?? []) + [ImageLoadingProgressSideEffect(block)]
+        }
+        
+        let task = KingfisherManager.shared.retrieveImage(
+            with: source,
+            options: options,
+            downloadTaskUpdated: { mutatingSelf.imageTask = $0 },
+            progressiveImageSetter: { self.base.setImage($0) },
+            referenceTaskIdentifierChecker: { issuedIdentifier == self.taskIdentifier },
+            completionHandler: { result in
+                CallbackQueue.mainCurrentOrAsync.execute {
+                    guard issuedIdentifier == self.taskIdentifier else {
+                        let reason: KingfisherError.ImageSettingErrorReason
+                        do {
+                            let value = try result.get()
+                            reason = .notCurrentSourceTask(result: value, error: nil, source: source)
+                        } catch {
+                            reason = .notCurrentSourceTask(result: nil, error: error, source: source)
+                        }
+                        let error = KingfisherError.imageSettingError(reason: reason)
+                        completionHandler?(.failure(error))
+                        return
+                    }
+                    
+                    mutatingSelf.imageTask = nil
+                    mutatingSelf.taskIdentifier = nil
+                    
+                    switch result {
+                        case .success(let value):
+                            self.base.setImage(value.image)
+                            completionHandler?(result)
+                            
+                        case .failure:
+                            if let image = options.onFailureImage {
+                                /**
+                                 * In iOS SDK 14.0-14.4 the image param was non-`nil`. The SDK changed in 14.5
+                                 * to allow `nil`. The compiler version 5.4 was introduced in this same SDK,
+                                 * which allows >=14.5 SDK to set a `nil` image. This compile check allows
+                                 * newer SDK users to set the image to `nil`, while still allowing older SDK
+                                 * users to compile the framework.
+                                 */
+                                #if compiler(>=5.4)
+                                self.base.setImage(image)
+                                #else // Let older SDK users deal with the older behavior.
+                                if let unwrapped = image {
+                                    self.base.setImage(unwrapped)
+                                }
+                                #endif   
+                            }
+                            completionHandler?(result)
+                    }
+                }
+            }
+        )
+        
+        mutatingSelf.imageTask = task
+        return task
+    }
+    
+    // MARK: Cancelling Image
+    
+    /// Cancel the image download task bounded to the image view if it is running.
+    /// Nothing will happen if the downloading has already finished.
+    public func cancelDownloadTask() {
+        imageTask?.cancel()
+    }
+}
+
+private var taskIdentifierKey: Void?
+private var imageTaskKey: Void?
+
+// MARK: Properties
+extension KingfisherWrapper where Base: CPListItem {
+
+    public private(set) var taskIdentifier: Source.Identifier.Value? {
+        get {
+            let box: Box<Source.Identifier.Value>? = getAssociatedObject(base, &taskIdentifierKey)
+            return box?.value
+        }
+        set {
+            let box = newValue.map { Box($0) }
+            setRetainedAssociatedObject(base, &taskIdentifierKey, box)
+        }
+    }
+
+    private var imageTask: DownloadTask? {
+        get { return getAssociatedObject(base, &imageTaskKey) }
+        set { setRetainedAssociatedObject(base, &imageTaskKey, newValue)}
+    }
+}
+#endif

Pods/Kingfisher/Sources/Extensions/ImageView+Kingfisher.swift

@@ -0,0 +1,537 @@
+//
+//  ImageView+Kingfisher.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 15/4/6.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if !os(watchOS)
+
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+extension KingfisherWrapper where Base: KFCrossPlatformImageView {
+
+    // MARK: Setting Image
+
+    /// Sets an image to the image view with a `Source`.
+    ///
+    /// - Parameters:
+    ///   - source: The `Source` object defines data information from network or a data provider.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    /// This is the easiest way to use Kingfisher to boost the image setting process from a source. Since all parameters
+    /// have a default value except the `source`, you can set an image from a certain URL to an image view like this:
+    ///
+    /// ```
+    /// // Set image from a network source.
+    /// let url = URL(string: "https://example.com/image.png")!
+    /// imageView.kf.setImage(with: .network(url))
+    ///
+    /// // Or set image from a data provider.
+    /// let provider = LocalFileImageDataProvider(fileURL: fileURL)
+    /// imageView.kf.setImage(with: .provider(provider))
+    /// ```
+    ///
+    /// For both `.network` and `.provider` source, there are corresponding view extension methods. So the code
+    /// above is equivalent to:
+    ///
+    /// ```
+    /// imageView.kf.setImage(with: url)
+    /// imageView.kf.setImage(with: provider)
+    /// ```
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the source.
+    /// Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with source: Source?,
+        placeholder: Placeholder? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        let options = KingfisherParsedOptionsInfo(KingfisherManager.shared.defaultOptions + (options ?? .empty))
+        return setImage(with: source, placeholder: placeholder, parsedOptions: options, progressBlock: progressBlock, completionHandler: completionHandler)
+    }
+
+    /// Sets an image to the image view with a `Source`.
+    ///
+    /// - Parameters:
+    ///   - source: The `Source` object defines data information from network or a data provider.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    /// This is the easiest way to use Kingfisher to boost the image setting process from a source. Since all parameters
+    /// have a default value except the `source`, you can set an image from a certain URL to an image view like this:
+    ///
+    /// ```
+    /// // Set image from a network source.
+    /// let url = URL(string: "https://example.com/image.png")!
+    /// imageView.kf.setImage(with: .network(url))
+    ///
+    /// // Or set image from a data provider.
+    /// let provider = LocalFileImageDataProvider(fileURL: fileURL)
+    /// imageView.kf.setImage(with: .provider(provider))
+    /// ```
+    ///
+    /// For both `.network` and `.provider` source, there are corresponding view extension methods. So the code
+    /// above is equivalent to:
+    ///
+    /// ```
+    /// imageView.kf.setImage(with: url)
+    /// imageView.kf.setImage(with: provider)
+    /// ```
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the source.
+    /// Since this method will perform UI changes, you must call it from the main thread.
+    /// The `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with source: Source?,
+        placeholder: Placeholder? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        return setImage(
+            with: source,
+            placeholder: placeholder,
+            options: options,
+            progressBlock: nil,
+            completionHandler: completionHandler
+        )
+    }
+
+    /// Sets an image to the image view with a requested resource.
+    ///
+    /// - Parameters:
+    ///   - resource: The `Resource` object contains information about the resource.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    /// This is the easiest way to use Kingfisher to boost the image setting process from network. Since all parameters
+    /// have a default value except the `resource`, you can set an image from a certain URL to an image view like this:
+    ///
+    /// ```
+    /// let url = URL(string: "https://example.com/image.png")!
+    /// imageView.kf.setImage(with: url)
+    /// ```
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the requested resource, from either cache
+    /// or network. Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with resource: Resource?,
+        placeholder: Placeholder? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        return setImage(
+            with: resource?.convertToSource(),
+            placeholder: placeholder,
+            options: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler)
+    }
+
+    /// Sets an image to the image view with a requested resource.
+    ///
+    /// - Parameters:
+    ///   - resource: The `Resource` object contains information about the resource.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    /// This is the easiest way to use Kingfisher to boost the image setting process from network. Since all parameters
+    /// have a default value except the `resource`, you can set an image from a certain URL to an image view like this:
+    ///
+    /// ```
+    /// let url = URL(string: "https://example.com/image.png")!
+    /// imageView.kf.setImage(with: url)
+    /// ```
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the requested resource, from either cache
+    /// or network. Since this method will perform UI changes, you must call it from the main thread.
+    /// The `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with resource: Resource?,
+        placeholder: Placeholder? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        return setImage(
+            with: resource,
+            placeholder: placeholder,
+            options: options,
+            progressBlock: nil,
+            completionHandler: completionHandler
+        )
+    }
+
+    /// Sets an image to the image view with a data provider.
+    ///
+    /// - Parameters:
+    ///   - provider: The `ImageDataProvider` object contains information about the data.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the image data, from either cache
+    /// or the data provider. Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with provider: ImageDataProvider?,
+        placeholder: Placeholder? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        return setImage(
+            with: provider.map { .provider($0) },
+            placeholder: placeholder,
+            options: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler)
+    }
+
+    /// Sets an image to the image view with a data provider.
+    ///
+    /// - Parameters:
+    ///   - provider: The `ImageDataProvider` object contains information about the data.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the image data, from either cache
+    /// or the data provider. Since this method will perform UI changes, you must call it from the main thread.
+    /// The `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with provider: ImageDataProvider?,
+        placeholder: Placeholder? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        return setImage(
+            with: provider,
+            placeholder: placeholder,
+            options: options,
+            progressBlock: nil,
+            completionHandler: completionHandler
+        )
+    }
+
+
+    func setImage(
+        with source: Source?,
+        placeholder: Placeholder? = nil,
+        parsedOptions: KingfisherParsedOptionsInfo,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        var mutatingSelf = self
+        guard let source = source else {
+            mutatingSelf.placeholder = placeholder
+            mutatingSelf.taskIdentifier = nil
+            completionHandler?(.failure(KingfisherError.imageSettingError(reason: .emptySource)))
+            return nil
+        }
+
+        var options = parsedOptions
+
+        let isEmptyImage = base.image == nil && self.placeholder == nil
+        if !options.keepCurrentImageWhileLoading || isEmptyImage {
+            // Always set placeholder while there is no image/placeholder yet.
+            mutatingSelf.placeholder = placeholder
+        }
+
+        let maybeIndicator = indicator
+        maybeIndicator?.startAnimatingView()
+
+        let issuedIdentifier = Source.Identifier.next()
+        mutatingSelf.taskIdentifier = issuedIdentifier
+
+        if base.shouldPreloadAllAnimation() {
+            options.preloadAllAnimationData = true
+        }
+
+        if let block = progressBlock {
+            options.onDataReceived = (options.onDataReceived ?? []) + [ImageLoadingProgressSideEffect(block)]
+        }
+
+        let task = KingfisherManager.shared.retrieveImage(
+            with: source,
+            options: options,
+            downloadTaskUpdated: { mutatingSelf.imageTask = $0 },
+            progressiveImageSetter: { self.base.image = $0 },
+            referenceTaskIdentifierChecker: { issuedIdentifier == self.taskIdentifier },
+            completionHandler: { result in
+                CallbackQueue.mainCurrentOrAsync.execute {
+                    maybeIndicator?.stopAnimatingView()
+                    guard issuedIdentifier == self.taskIdentifier else {
+                        let reason: KingfisherError.ImageSettingErrorReason
+                        do {
+                            let value = try result.get()
+                            reason = .notCurrentSourceTask(result: value, error: nil, source: source)
+                        } catch {
+                            reason = .notCurrentSourceTask(result: nil, error: error, source: source)
+                        }
+                        let error = KingfisherError.imageSettingError(reason: reason)
+                        completionHandler?(.failure(error))
+                        return
+                    }
+
+                    mutatingSelf.imageTask = nil
+                    mutatingSelf.taskIdentifier = nil
+
+                    switch result {
+                    case .success(let value):
+                        guard self.needsTransition(options: options, cacheType: value.cacheType) else {
+                            mutatingSelf.placeholder = nil
+                            self.base.image = value.image
+                            completionHandler?(result)
+                            return
+                        }
+
+                        self.makeTransition(image: value.image, transition: options.transition) {
+                            completionHandler?(result)
+                        }
+
+                    case .failure:
+                        if let image = options.onFailureImage {
+                            mutatingSelf.placeholder = nil
+                            self.base.image = image
+                        }
+                        completionHandler?(result)
+                    }
+                }
+            }
+        )
+        mutatingSelf.imageTask = task
+        return task
+    }
+
+    // MARK: Cancelling Downloading Task
+
+    /// Cancels the image download task of the image view if it is running.
+    /// Nothing will happen if the downloading has already finished.
+    public func cancelDownloadTask() {
+        imageTask?.cancel()
+    }
+
+    private func needsTransition(options: KingfisherParsedOptionsInfo, cacheType: CacheType) -> Bool {
+        switch options.transition {
+        case .none:
+            return false
+        #if os(macOS)
+        case .fade: // Fade is only a placeholder for SwiftUI on macOS.
+            return false
+        #else
+        default:
+            if options.forceTransition { return true }
+            if cacheType == .none { return true }
+            return false
+        #endif
+        }
+    }
+
+    private func makeTransition(image: KFCrossPlatformImage, transition: ImageTransition, done: @escaping () -> Void) {
+        #if !os(macOS)
+        // Force hiding the indicator without transition first.
+        UIView.transition(
+            with: self.base,
+            duration: 0.0,
+            options: [],
+            animations: { self.indicator?.stopAnimatingView() },
+            completion: { _ in
+                var mutatingSelf = self
+                mutatingSelf.placeholder = nil
+                UIView.transition(
+                    with: self.base,
+                    duration: transition.duration,
+                    options: [transition.animationOptions, .allowUserInteraction],
+                    animations: { transition.animations?(self.base, image) },
+                    completion: { finished in
+                        transition.completion?(finished)
+                        done()
+                    }
+                )
+            }
+        )
+        #else
+        done()
+        #endif
+    }
+}
+
+// MARK: - Associated Object
+private var taskIdentifierKey: Void?
+private var indicatorKey: Void?
+private var indicatorTypeKey: Void?
+private var placeholderKey: Void?
+private var imageTaskKey: Void?
+
+extension KingfisherWrapper where Base: KFCrossPlatformImageView {
+
+    // MARK: Properties
+    public private(set) var taskIdentifier: Source.Identifier.Value? {
+        get {
+            let box: Box<Source.Identifier.Value>? = getAssociatedObject(base, &taskIdentifierKey)
+            return box?.value
+        }
+        set {
+            let box = newValue.map { Box($0) }
+            setRetainedAssociatedObject(base, &taskIdentifierKey, box)
+        }
+    }
+
+    /// Holds which indicator type is going to be used.
+    /// Default is `.none`, means no indicator will be shown while downloading.
+    public var indicatorType: IndicatorType {
+        get {
+            return getAssociatedObject(base, &indicatorTypeKey) ?? .none
+        }
+        
+        set {
+            switch newValue {
+            case .none: indicator = nil
+            case .activity: indicator = ActivityIndicator()
+            case .image(let data): indicator = ImageIndicator(imageData: data)
+            case .custom(let anIndicator): indicator = anIndicator
+            }
+
+            setRetainedAssociatedObject(base, &indicatorTypeKey, newValue)
+        }
+    }
+    
+    /// Holds any type that conforms to the protocol `Indicator`.
+    /// The protocol `Indicator` has a `view` property that will be shown when loading an image.
+    /// It will be `nil` if `indicatorType` is `.none`.
+    public private(set) var indicator: Indicator? {
+        get {
+            let box: Box<Indicator>? = getAssociatedObject(base, &indicatorKey)
+            return box?.value
+        }
+        
+        set {
+            // Remove previous
+            if let previousIndicator = indicator {
+                previousIndicator.view.removeFromSuperview()
+            }
+            
+            // Add new
+            if let newIndicator = newValue {
+                // Set default indicator layout
+                let view = newIndicator.view
+                
+                base.addSubview(view)
+                view.translatesAutoresizingMaskIntoConstraints = false
+                view.centerXAnchor.constraint(
+                    equalTo: base.centerXAnchor, constant: newIndicator.centerOffset.x).isActive = true
+                view.centerYAnchor.constraint(
+                    equalTo: base.centerYAnchor, constant: newIndicator.centerOffset.y).isActive = true
+
+                switch newIndicator.sizeStrategy(in: base) {
+                case .intrinsicSize:
+                    break
+                case .full:
+                    view.heightAnchor.constraint(equalTo: base.heightAnchor, constant: 0).isActive = true
+                    view.widthAnchor.constraint(equalTo: base.widthAnchor, constant: 0).isActive = true
+                case .size(let size):
+                    view.heightAnchor.constraint(equalToConstant: size.height).isActive = true
+                    view.widthAnchor.constraint(equalToConstant: size.width).isActive = true
+                }
+                
+                newIndicator.view.isHidden = true
+            }
+
+            // Save in associated object
+            // Wrap newValue with Box to workaround an issue that Swift does not recognize
+            // and casting protocol for associate object correctly. https://github.com/onevcat/Kingfisher/issues/872
+            setRetainedAssociatedObject(base, &indicatorKey, newValue.map(Box.init))
+        }
+    }
+    
+    private var imageTask: DownloadTask? {
+        get { return getAssociatedObject(base, &imageTaskKey) }
+        set { setRetainedAssociatedObject(base, &imageTaskKey, newValue)}
+    }
+
+    /// Represents the `Placeholder` used for this image view. A `Placeholder` will be shown in the view while
+    /// it is downloading an image.
+    public private(set) var placeholder: Placeholder? {
+        get { return getAssociatedObject(base, &placeholderKey) }
+        set {
+            if let previousPlaceholder = placeholder {
+                previousPlaceholder.remove(from: base)
+            }
+            
+            if let newPlaceholder = newValue {
+                newPlaceholder.add(to: base)
+            } else {
+                base.image = nil
+            }
+            setRetainedAssociatedObject(base, &placeholderKey, newValue)
+        }
+    }
+}
+
+
+extension KFCrossPlatformImageView {
+    @objc func shouldPreloadAllAnimation() -> Bool { return true }
+}
+
+#endif

Pods/Kingfisher/Sources/Extensions/NSButton+Kingfisher.swift

@@ -0,0 +1,362 @@
+//
+//  NSButton+Kingfisher.swift
+//  Kingfisher
+//
+//  Created by Jie Zhang on 14/04/2016.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if canImport(AppKit) && !targetEnvironment(macCatalyst)
+
+import AppKit
+
+extension KingfisherWrapper where Base: NSButton {
+
+    // MARK: Setting Image
+
+    /// Sets an image to the button with a source.
+    ///
+    /// - Parameters:
+    ///   - source: The `Source` object contains information about how to get the image.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    /// Internally, this method will use `KingfisherManager` to get the requested source.
+    /// Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with source: Source?,
+        placeholder: KFCrossPlatformImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        let options = KingfisherParsedOptionsInfo(KingfisherManager.shared.defaultOptions + (options ?? .empty))
+        return setImage(
+            with: source,
+            placeholder: placeholder,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler
+        )
+    }
+
+    /// Sets an image to the button with a requested resource.
+    ///
+    /// - Parameters:
+    ///   - resource: The `Resource` object contains information about the resource.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    /// Internally, this method will use `KingfisherManager` to get the requested resource, from either cache
+    /// or network. Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with resource: Resource?,
+        placeholder: KFCrossPlatformImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        return setImage(
+            with: resource?.convertToSource(),
+            placeholder: placeholder,
+            options: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler)
+    }
+
+    func setImage(
+        with source: Source?,
+        placeholder: KFCrossPlatformImage? = nil,
+        parsedOptions: KingfisherParsedOptionsInfo,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        var mutatingSelf = self
+        guard let source = source else {
+            base.image = placeholder
+            mutatingSelf.taskIdentifier = nil
+            completionHandler?(.failure(KingfisherError.imageSettingError(reason: .emptySource)))
+            return nil
+        }
+
+        var options = parsedOptions
+        if !options.keepCurrentImageWhileLoading {
+            base.image = placeholder
+        }
+
+        let issuedIdentifier = Source.Identifier.next()
+        mutatingSelf.taskIdentifier = issuedIdentifier
+
+        if let block = progressBlock {
+            options.onDataReceived = (options.onDataReceived ?? []) + [ImageLoadingProgressSideEffect(block)]
+        }
+
+        let task = KingfisherManager.shared.retrieveImage(
+            with: source,
+            options: options,
+            downloadTaskUpdated: { mutatingSelf.imageTask = $0 },
+            progressiveImageSetter: { self.base.image = $0 },
+            referenceTaskIdentifierChecker: { issuedIdentifier == self.taskIdentifier },
+            completionHandler: { result in
+                CallbackQueue.mainCurrentOrAsync.execute {
+                    guard issuedIdentifier == self.taskIdentifier else {
+                        let reason: KingfisherError.ImageSettingErrorReason
+                        do {
+                            let value = try result.get()
+                            reason = .notCurrentSourceTask(result: value, error: nil, source: source)
+                        } catch {
+                            reason = .notCurrentSourceTask(result: nil, error: error, source: source)
+                        }
+                        let error = KingfisherError.imageSettingError(reason: reason)
+                        completionHandler?(.failure(error))
+                        return
+                    }
+
+                    mutatingSelf.imageTask = nil
+                    mutatingSelf.taskIdentifier = nil
+
+                    switch result {
+                    case .success(let value):
+                        self.base.image = value.image
+                        completionHandler?(result)
+
+                    case .failure:
+                        if let image = options.onFailureImage {
+                            self.base.image = image
+                        }
+                        completionHandler?(result)
+                    }
+                }
+            }
+        )
+
+        mutatingSelf.imageTask = task
+        return task
+    }
+
+    // MARK: Cancelling Downloading Task
+
+    /// Cancels the image download task of the button if it is running.
+    /// Nothing will happen if the downloading has already finished.
+    public func cancelImageDownloadTask() {
+        imageTask?.cancel()
+    }
+
+    // MARK: Setting Alternate Image
+
+    @discardableResult
+    public func setAlternateImage(
+        with source: Source?,
+        placeholder: KFCrossPlatformImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        let options = KingfisherParsedOptionsInfo(KingfisherManager.shared.defaultOptions + (options ?? .empty))
+        return setAlternateImage(
+            with: source,
+            placeholder: placeholder,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler
+        )
+    }
+
+    /// Sets an alternate image to the button with a requested resource.
+    ///
+    /// - Parameters:
+    ///   - resource: The `Resource` object contains information about the resource.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    /// Internally, this method will use `KingfisherManager` to get the requested resource, from either cache
+    /// or network. Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setAlternateImage(
+        with resource: Resource?,
+        placeholder: KFCrossPlatformImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        return setAlternateImage(
+            with: resource?.convertToSource(),
+            placeholder: placeholder,
+            options: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler)
+    }
+
+    func setAlternateImage(
+        with source: Source?,
+        placeholder: KFCrossPlatformImage? = nil,
+        parsedOptions: KingfisherParsedOptionsInfo,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        var mutatingSelf = self
+        guard let source = source else {
+            base.alternateImage = placeholder
+            mutatingSelf.alternateTaskIdentifier = nil
+            completionHandler?(.failure(KingfisherError.imageSettingError(reason: .emptySource)))
+            return nil
+        }
+
+        var options = parsedOptions
+        if !options.keepCurrentImageWhileLoading {
+            base.alternateImage = placeholder
+        }
+
+        let issuedIdentifier = Source.Identifier.next()
+        mutatingSelf.alternateTaskIdentifier = issuedIdentifier
+
+        if let block = progressBlock {
+            options.onDataReceived = (options.onDataReceived ?? []) + [ImageLoadingProgressSideEffect(block)]
+        }
+
+        if let provider = ImageProgressiveProvider(options, refresh: { image in
+            self.base.alternateImage = image
+        }) {
+            options.onDataReceived = (options.onDataReceived ?? []) + [provider]
+        }
+
+        options.onDataReceived?.forEach {
+            $0.onShouldApply = { issuedIdentifier == self.alternateTaskIdentifier }
+        }
+
+        let task = KingfisherManager.shared.retrieveImage(
+            with: source,
+            options: options,
+            downloadTaskUpdated: { mutatingSelf.alternateImageTask = $0 },
+            completionHandler: { result in
+                CallbackQueue.mainCurrentOrAsync.execute {
+                    guard issuedIdentifier == self.alternateTaskIdentifier else {
+                        let reason: KingfisherError.ImageSettingErrorReason
+                        do {
+                            let value = try result.get()
+                            reason = .notCurrentSourceTask(result: value, error: nil, source: source)
+                        } catch {
+                            reason = .notCurrentSourceTask(result: nil, error: error, source: source)
+                        }
+                        let error = KingfisherError.imageSettingError(reason: reason)
+                        completionHandler?(.failure(error))
+                        return
+                    }
+
+                    mutatingSelf.alternateImageTask = nil
+                    mutatingSelf.alternateTaskIdentifier = nil
+
+                    switch result {
+                    case .success(let value):
+                        self.base.alternateImage = value.image
+                        completionHandler?(result)
+
+                    case .failure:
+                        if let image = options.onFailureImage {
+                            self.base.alternateImage = image
+                        }
+                        completionHandler?(result)
+                    }
+                }
+            }
+        )
+
+        mutatingSelf.alternateImageTask = task
+        return task
+    }
+
+    // MARK: Cancelling Alternate Image Downloading Task
+
+    /// Cancels the alternate image download task of the button if it is running.
+    /// Nothing will happen if the downloading has already finished.
+    public func cancelAlternateImageDownloadTask() {
+        alternateImageTask?.cancel()
+    }
+}
+
+
+// MARK: - Associated Object
+private var taskIdentifierKey: Void?
+private var imageTaskKey: Void?
+
+private var alternateTaskIdentifierKey: Void?
+private var alternateImageTaskKey: Void?
+
+extension KingfisherWrapper where Base: NSButton {
+
+    // MARK: Properties
+    
+    public private(set) var taskIdentifier: Source.Identifier.Value? {
+        get {
+            let box: Box<Source.Identifier.Value>? = getAssociatedObject(base, &taskIdentifierKey)
+            return box?.value
+        }
+        set {
+            let box = newValue.map { Box($0) }
+            setRetainedAssociatedObject(base, &taskIdentifierKey, box)
+        }
+    }
+    
+    private var imageTask: DownloadTask? {
+        get { return getAssociatedObject(base, &imageTaskKey) }
+        set { setRetainedAssociatedObject(base, &imageTaskKey, newValue)}
+    }
+
+    public private(set) var alternateTaskIdentifier: Source.Identifier.Value? {
+        get {
+            let box: Box<Source.Identifier.Value>? = getAssociatedObject(base, &alternateTaskIdentifierKey)
+            return box?.value
+        }
+        set {
+            let box = newValue.map { Box($0) }
+            setRetainedAssociatedObject(base, &alternateTaskIdentifierKey, box)
+        }
+    }
+
+    private var alternateImageTask: DownloadTask? {
+        get { return getAssociatedObject(base, &alternateImageTaskKey) }
+        set { setRetainedAssociatedObject(base, &alternateImageTaskKey, newValue)}
+    }
+}
+#endif

Pods/Kingfisher/Sources/Extensions/NSTextAttachment+Kingfisher.swift

@@ -0,0 +1,271 @@
+//
+//  NSTextAttachment+Kingfisher.swift
+//  Kingfisher
+//
+//  Created by Benjamin Briggs on 22/07/2019.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if !os(watchOS)
+
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+extension KingfisherWrapper where Base: NSTextAttachment {
+
+    // MARK: Setting Image
+
+    /// Sets an image to the text attachment with a source.
+    ///
+    /// - Parameters:
+    ///   - source: The `Source` object defines data information from network or a data provider.
+    ///   - attributedView: The owner of the attributed string which this `NSTextAttachment` is added.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the requested source
+    /// Since this method will perform UI changes, you must call it from the main thread.
+    ///
+    /// The retrieved image will be set to `NSTextAttachment.image` property. Because it is not an image view based
+    /// rendering, options related to view, such as `.transition`, are not supported.
+    ///
+    /// Kingfisher will call `setNeedsDisplay` on the `attributedView` when the image task done. It gives the view a
+    /// chance to render the attributed string again for displaying the downloaded image. For example, if you set an
+    /// attributed with this `NSTextAttachment` to a `UILabel` object, pass it as the `attributedView` parameter.
+    ///
+    /// Here is a typical use case:
+    ///
+    /// ```swift
+    /// let attributedText = NSMutableAttributedString(string: "Hello World")
+    /// let textAttachment = NSTextAttachment()
+    ///
+    /// textAttachment.kf.setImage(
+    ///     with: URL(string: "https://onevcat.com/assets/images/avatar.jpg")!,
+    ///     attributedView: label,
+    ///     options: [
+    ///        .processor(
+    ///            ResizingImageProcessor(referenceSize: .init(width: 30, height: 30))
+    ///            |> RoundCornerImageProcessor(cornerRadius: 15))
+    ///     ]
+    /// )
+    /// attributedText.replaceCharacters(in: NSRange(), with: NSAttributedString(attachment: textAttachment))
+    /// label.attributedText = attributedText
+    /// ```
+    ///
+    @discardableResult
+    public func setImage(
+        with source: Source?,
+        attributedView: @autoclosure @escaping () -> KFCrossPlatformView,
+        placeholder: KFCrossPlatformImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        let options = KingfisherParsedOptionsInfo(KingfisherManager.shared.defaultOptions + (options ?? .empty))
+        return setImage(
+            with: source,
+            attributedView: attributedView,
+            placeholder: placeholder,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler
+        )
+    }
+
+    /// Sets an image to the text attachment with a source.
+    ///
+    /// - Parameters:
+    ///   - resource: The `Resource` object contains information about the resource.
+    ///   - attributedView: The owner of the attributed string which this `NSTextAttachment` is added.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the requested source
+    /// Since this method will perform UI changes, you must call it from the main thread.
+    ///
+    /// The retrieved image will be set to `NSTextAttachment.image` property. Because it is not an image view based
+    /// rendering, options related to view, such as `.transition`, are not supported.
+    ///
+    /// Kingfisher will call `setNeedsDisplay` on the `attributedView` when the image task done. It gives the view a
+    /// chance to render the attributed string again for displaying the downloaded image. For example, if you set an
+    /// attributed with this `NSTextAttachment` to a `UILabel` object, pass it as the `attributedView` parameter.
+    ///
+    /// Here is a typical use case:
+    ///
+    /// ```swift
+    /// let attributedText = NSMutableAttributedString(string: "Hello World")
+    /// let textAttachment = NSTextAttachment()
+    ///
+    /// textAttachment.kf.setImage(
+    ///     with: URL(string: "https://onevcat.com/assets/images/avatar.jpg")!,
+    ///     attributedView: label,
+    ///     options: [
+    ///        .processor(
+    ///            ResizingImageProcessor(referenceSize: .init(width: 30, height: 30))
+    ///            |> RoundCornerImageProcessor(cornerRadius: 15))
+    ///     ]
+    /// )
+    /// attributedText.replaceCharacters(in: NSRange(), with: NSAttributedString(attachment: textAttachment))
+    /// label.attributedText = attributedText
+    /// ```
+    ///
+    @discardableResult
+    public func setImage(
+        with resource: Resource?,
+        attributedView: @autoclosure @escaping () -> KFCrossPlatformView,
+        placeholder: KFCrossPlatformImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        let options = KingfisherParsedOptionsInfo(KingfisherManager.shared.defaultOptions + (options ?? .empty))
+        return setImage(
+            with: resource.map { .network($0) },
+            attributedView: attributedView,
+            placeholder: placeholder,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler
+        )
+    }
+
+    func setImage(
+        with source: Source?,
+        attributedView: @escaping () -> KFCrossPlatformView,
+        placeholder: KFCrossPlatformImage? = nil,
+        parsedOptions: KingfisherParsedOptionsInfo,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        var mutatingSelf = self
+        guard let source = source else {
+            base.image = placeholder
+            mutatingSelf.taskIdentifier = nil
+            completionHandler?(.failure(KingfisherError.imageSettingError(reason: .emptySource)))
+            return nil
+        }
+
+        var options = parsedOptions
+        if !options.keepCurrentImageWhileLoading {
+            base.image = placeholder
+        }
+
+        let issuedIdentifier = Source.Identifier.next()
+        mutatingSelf.taskIdentifier = issuedIdentifier
+
+        if let block = progressBlock {
+            options.onDataReceived = (options.onDataReceived ?? []) + [ImageLoadingProgressSideEffect(block)]
+        }
+
+        let task = KingfisherManager.shared.retrieveImage(
+            with: source,
+            options: options,
+            progressiveImageSetter: { self.base.image = $0 },
+            referenceTaskIdentifierChecker: { issuedIdentifier == self.taskIdentifier },
+            completionHandler: { result in
+                CallbackQueue.mainCurrentOrAsync.execute {
+                    guard issuedIdentifier == self.taskIdentifier else {
+                        let reason: KingfisherError.ImageSettingErrorReason
+                        do {
+                            let value = try result.get()
+                            reason = .notCurrentSourceTask(result: value, error: nil, source: source)
+                        } catch {
+                            reason = .notCurrentSourceTask(result: nil, error: error, source: source)
+                        }
+                        let error = KingfisherError.imageSettingError(reason: reason)
+                        completionHandler?(.failure(error))
+                        return
+                    }
+
+                    mutatingSelf.imageTask = nil
+                    mutatingSelf.taskIdentifier = nil
+
+                    switch result {
+                    case .success(let value):
+                        self.base.image = value.image
+                        let view = attributedView()
+                        #if canImport(UIKit)
+                        view.setNeedsDisplay()
+                        #else
+                        view.setNeedsDisplay(view.bounds)
+                        #endif
+                    case .failure:
+                        if let image = options.onFailureImage {
+                            self.base.image = image
+                        }
+                    }
+                    completionHandler?(result)
+                }
+        }
+        )
+
+        mutatingSelf.imageTask = task
+        return task
+    }
+
+    // MARK: Cancelling Image
+
+    /// Cancel the image download task bounded to the text attachment if it is running.
+    /// Nothing will happen if the downloading has already finished.
+    public func cancelDownloadTask() {
+        imageTask?.cancel()
+    }
+}
+
+private var taskIdentifierKey: Void?
+private var imageTaskKey: Void?
+
+// MARK: Properties
+extension KingfisherWrapper where Base: NSTextAttachment {
+
+    public private(set) var taskIdentifier: Source.Identifier.Value? {
+        get {
+            let box: Box<Source.Identifier.Value>? = getAssociatedObject(base, &taskIdentifierKey)
+            return box?.value
+        }
+        set {
+            let box = newValue.map { Box($0) }
+            setRetainedAssociatedObject(base, &taskIdentifierKey, box)
+        }
+    }
+
+    private var imageTask: DownloadTask? {
+        get { return getAssociatedObject(base, &imageTaskKey) }
+        set { setRetainedAssociatedObject(base, &imageTaskKey, newValue)}
+    }
+}
+
+#endif

Pods/Kingfisher/Sources/Extensions/TVMonogramView+Kingfisher.swift

@@ -0,0 +1,209 @@
+//
+//  TVMonogramView+Kingfisher.swift
+//  Kingfisher
+//
+//  Created by Marvin Nazari on 2020-12-07.
+//
+//  Copyright (c) 2020 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+#if canImport(TVUIKit)
+
+import TVUIKit
+
+@available(tvOS 12.0, *)
+extension KingfisherWrapper where Base: TVMonogramView {
+
+    // MARK: Setting Image
+
+    /// Sets an image to the image view with a source.
+    ///
+    /// - Parameters:
+    ///   - source: The `Source` object contains information about the image.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the requested source
+    /// Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with source: Source?,
+        placeholder: KFCrossPlatformImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        let options = KingfisherParsedOptionsInfo(KingfisherManager.shared.defaultOptions + (options ?? .empty))
+        return setImage(
+            with: source,
+            placeholder: placeholder,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler
+        )
+    }
+
+    func setImage(
+        with source: Source?,
+        placeholder: KFCrossPlatformImage? = nil,
+        parsedOptions: KingfisherParsedOptionsInfo,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        var mutatingSelf = self
+        guard let source = source else {
+            base.image = placeholder
+            mutatingSelf.taskIdentifier = nil
+            completionHandler?(.failure(KingfisherError.imageSettingError(reason: .emptySource)))
+            return nil
+        }
+
+        var options = parsedOptions
+        if !options.keepCurrentImageWhileLoading {
+            base.image = placeholder
+        }
+
+        let issuedIdentifier = Source.Identifier.next()
+        mutatingSelf.taskIdentifier = issuedIdentifier
+
+        if let block = progressBlock {
+            options.onDataReceived = (options.onDataReceived ?? []) + [ImageLoadingProgressSideEffect(block)]
+        }
+
+        let task = KingfisherManager.shared.retrieveImage(
+            with: source,
+            options: options,
+            downloadTaskUpdated: { mutatingSelf.imageTask = $0 },
+            progressiveImageSetter: { self.base.image = $0 },
+            referenceTaskIdentifierChecker: { issuedIdentifier == self.taskIdentifier },
+            completionHandler: { result in
+                CallbackQueue.mainCurrentOrAsync.execute {
+                    guard issuedIdentifier == self.taskIdentifier else {
+                        let reason: KingfisherError.ImageSettingErrorReason
+                        do {
+                            let value = try result.get()
+                            reason = .notCurrentSourceTask(result: value, error: nil, source: source)
+                        } catch {
+                            reason = .notCurrentSourceTask(result: nil, error: error, source: source)
+                        }
+                        let error = KingfisherError.imageSettingError(reason: reason)
+                        completionHandler?(.failure(error))
+                        return
+                    }
+
+                    mutatingSelf.imageTask = nil
+                    mutatingSelf.taskIdentifier = nil
+
+                    switch result {
+                    case .success(let value):
+                        self.base.image = value.image
+                        completionHandler?(result)
+
+                    case .failure:
+                        if let image = options.onFailureImage {
+                            self.base.image = image
+                        }
+                        completionHandler?(result)
+                    }
+                }
+            }
+        )
+
+        mutatingSelf.imageTask = task
+        return task
+    }
+    
+    /// Sets an image to the image view with a requested resource.
+    ///
+    /// - Parameters:
+    ///   - resource: The `Resource` object contains information about the image.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the requested resource, from either cache
+    /// or network. Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with resource: Resource?,
+        placeholder: KFCrossPlatformImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        return setImage(
+            with: resource?.convertToSource(),
+            placeholder: placeholder,
+            options: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler)
+    }
+
+    // MARK: Cancelling Image
+
+    /// Cancel the image download task bounded to the image view if it is running.
+    /// Nothing will happen if the downloading has already finished.
+    public func cancelDownloadTask() {
+        imageTask?.cancel()
+    }
+}
+
+private var taskIdentifierKey: Void?
+private var imageTaskKey: Void?
+
+// MARK: Properties
+@available(tvOS 12.0, *)
+extension KingfisherWrapper where Base: TVMonogramView {
+    
+    public private(set) var taskIdentifier: Source.Identifier.Value? {
+        get {
+            let box: Box<Source.Identifier.Value>? = getAssociatedObject(base, &taskIdentifierKey)
+            return box?.value
+        }
+        set {
+            let box = newValue.map { Box($0) }
+            setRetainedAssociatedObject(base, &taskIdentifierKey, box)
+        }
+    }
+
+    private var imageTask: DownloadTask? {
+        get { return getAssociatedObject(base, &imageTaskKey) }
+        set { setRetainedAssociatedObject(base, &imageTaskKey, newValue)}
+    }
+}
+
+#endif

Pods/Kingfisher/Sources/Extensions/UIButton+Kingfisher.swift

@@ -0,0 +1,400 @@
+//
+//  UIButton+Kingfisher.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 15/4/13.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if !os(watchOS)
+
+#if canImport(UIKit)
+import UIKit
+
+extension KingfisherWrapper where Base: UIButton {
+
+    // MARK: Setting Image
+    /// Sets an image to the button for a specified state with a source.
+    ///
+    /// - Parameters:
+    ///   - source: The `Source` object contains information about the image.
+    ///   - state: The button state to which the image should be set.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    /// Internally, this method will use `KingfisherManager` to get the requested source, from either cache
+    /// or network. Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with source: Source?,
+        for state: UIControl.State,
+        placeholder: UIImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        let options = KingfisherParsedOptionsInfo(KingfisherManager.shared.defaultOptions + (options ?? .empty))
+        return setImage(
+            with: source,
+            for: state,
+            placeholder: placeholder,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler
+        )
+    }
+    
+    /// Sets an image to the button for a specified state with a requested resource.
+    ///
+    /// - Parameters:
+    ///   - resource: The `Resource` object contains information about the resource.
+    ///   - state: The button state to which the image should be set.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    /// Internally, this method will use `KingfisherManager` to get the requested resource, from either cache
+    /// or network. Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with resource: Resource?,
+        for state: UIControl.State,
+        placeholder: UIImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        return setImage(
+            with: resource?.convertToSource(),
+            for: state,
+            placeholder: placeholder,
+            options: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler)
+    }
+
+    @discardableResult
+    public func setImage(
+        with source: Source?,
+        for state: UIControl.State,
+        placeholder: UIImage? = nil,
+        parsedOptions: KingfisherParsedOptionsInfo,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        guard let source = source else {
+            base.setImage(placeholder, for: state)
+            setTaskIdentifier(nil, for: state)
+            completionHandler?(.failure(KingfisherError.imageSettingError(reason: .emptySource)))
+            return nil
+        }
+
+        var options = parsedOptions
+        if !options.keepCurrentImageWhileLoading {
+            base.setImage(placeholder, for: state)
+        }
+
+        var mutatingSelf = self
+        let issuedIdentifier = Source.Identifier.next()
+        setTaskIdentifier(issuedIdentifier, for: state)
+
+        if let block = progressBlock {
+            options.onDataReceived = (options.onDataReceived ?? []) + [ImageLoadingProgressSideEffect(block)]
+        }
+
+        let task = KingfisherManager.shared.retrieveImage(
+            with: source,
+            options: options,
+            downloadTaskUpdated: { mutatingSelf.imageTask = $0 },
+            progressiveImageSetter: { self.base.setImage($0, for: state) },
+            referenceTaskIdentifierChecker: { issuedIdentifier == self.taskIdentifier(for: state) },
+            completionHandler: { result in
+                CallbackQueue.mainCurrentOrAsync.execute {
+                    guard issuedIdentifier == self.taskIdentifier(for: state) else {
+                        let reason: KingfisherError.ImageSettingErrorReason
+                        do {
+                            let value = try result.get()
+                            reason = .notCurrentSourceTask(result: value, error: nil, source: source)
+                        } catch {
+                            reason = .notCurrentSourceTask(result: nil, error: error, source: source)
+                        }
+                        let error = KingfisherError.imageSettingError(reason: reason)
+                        completionHandler?(.failure(error))
+                        return
+                    }
+
+                    mutatingSelf.imageTask = nil
+                    mutatingSelf.setTaskIdentifier(nil, for: state)
+
+                    switch result {
+                    case .success(let value):
+                        self.base.setImage(value.image, for: state)
+                        completionHandler?(result)
+
+                    case .failure:
+                        if let image = options.onFailureImage {
+                            self.base.setImage(image, for: state)
+                        }
+                        completionHandler?(result)
+                    }
+                }
+            }
+        )
+
+        mutatingSelf.imageTask = task
+        return task
+    }
+
+    // MARK: Cancelling Downloading Task
+    
+    /// Cancels the image download task of the button if it is running.
+    /// Nothing will happen if the downloading has already finished.
+    public func cancelImageDownloadTask() {
+        imageTask?.cancel()
+    }
+
+    // MARK: Setting Background Image
+
+    /// Sets a background image to the button for a specified state with a source.
+    ///
+    /// - Parameters:
+    ///   - source: The `Source` object contains information about the image.
+    ///   - state: The button state to which the image should be set.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    /// Internally, this method will use `KingfisherManager` to get the requested source
+    /// Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setBackgroundImage(
+        with source: Source?,
+        for state: UIControl.State,
+        placeholder: UIImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        let options = KingfisherParsedOptionsInfo(KingfisherManager.shared.defaultOptions + (options ?? .empty))
+        return setBackgroundImage(
+            with: source,
+            for: state,
+            placeholder: placeholder,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler
+        )
+    }
+
+    /// Sets a background image to the button for a specified state with a requested resource.
+    ///
+    /// - Parameters:
+    ///   - resource: The `Resource` object contains information about the resource.
+    ///   - state: The button state to which the image should be set.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    /// Internally, this method will use `KingfisherManager` to get the requested resource, from either cache
+    /// or network. Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setBackgroundImage(
+        with resource: Resource?,
+        for state: UIControl.State,
+        placeholder: UIImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        return setBackgroundImage(
+            with: resource?.convertToSource(),
+            for: state,
+            placeholder: placeholder,
+            options: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler)
+    }
+
+    func setBackgroundImage(
+        with source: Source?,
+        for state: UIControl.State,
+        placeholder: UIImage? = nil,
+        parsedOptions: KingfisherParsedOptionsInfo,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        guard let source = source else {
+            base.setBackgroundImage(placeholder, for: state)
+            setBackgroundTaskIdentifier(nil, for: state)
+            completionHandler?(.failure(KingfisherError.imageSettingError(reason: .emptySource)))
+            return nil
+        }
+
+        var options = parsedOptions
+        if !options.keepCurrentImageWhileLoading {
+            base.setBackgroundImage(placeholder, for: state)
+        }
+
+        var mutatingSelf = self
+        let issuedIdentifier = Source.Identifier.next()
+        setBackgroundTaskIdentifier(issuedIdentifier, for: state)
+
+        if let block = progressBlock {
+            options.onDataReceived = (options.onDataReceived ?? []) + [ImageLoadingProgressSideEffect(block)]
+        }
+
+        let task = KingfisherManager.shared.retrieveImage(
+            with: source,
+            options: options,
+            downloadTaskUpdated: { mutatingSelf.backgroundImageTask = $0 },
+            progressiveImageSetter: { self.base.setBackgroundImage($0, for: state) },
+            referenceTaskIdentifierChecker: { issuedIdentifier == self.backgroundTaskIdentifier(for: state) },
+            completionHandler: { result in
+                CallbackQueue.mainCurrentOrAsync.execute {
+                    guard issuedIdentifier == self.backgroundTaskIdentifier(for: state) else {
+                        let reason: KingfisherError.ImageSettingErrorReason
+                        do {
+                            let value = try result.get()
+                            reason = .notCurrentSourceTask(result: value, error: nil, source: source)
+                        } catch {
+                            reason = .notCurrentSourceTask(result: nil, error: error, source: source)
+                        }
+                        let error = KingfisherError.imageSettingError(reason: reason)
+                        completionHandler?(.failure(error))
+                        return
+                    }
+
+                    mutatingSelf.backgroundImageTask = nil
+                    mutatingSelf.setBackgroundTaskIdentifier(nil, for: state)
+
+                    switch result {
+                    case .success(let value):
+                        self.base.setBackgroundImage(value.image, for: state)
+                        completionHandler?(result)
+
+                    case .failure:
+                        if let image = options.onFailureImage {
+                            self.base.setBackgroundImage(image, for: state)
+                        }
+                        completionHandler?(result)
+                    }
+                }
+            }
+        )
+
+        mutatingSelf.backgroundImageTask = task
+        return task
+    }
+
+    // MARK: Cancelling Background Downloading Task
+    
+    /// Cancels the background image download task of the button if it is running.
+    /// Nothing will happen if the downloading has already finished.
+    public func cancelBackgroundImageDownloadTask() {
+        backgroundImageTask?.cancel()
+    }
+}
+
+// MARK: - Associated Object
+private var taskIdentifierKey: Void?
+private var imageTaskKey: Void?
+
+// MARK: Properties
+extension KingfisherWrapper where Base: UIButton {
+
+    private typealias TaskIdentifier = Box<[UInt: Source.Identifier.Value]>
+    
+    public func taskIdentifier(for state: UIControl.State) -> Source.Identifier.Value? {
+        return taskIdentifierInfo.value[state.rawValue]
+    }
+
+    private func setTaskIdentifier(_ identifier: Source.Identifier.Value?, for state: UIControl.State) {
+        taskIdentifierInfo.value[state.rawValue] = identifier
+    }
+    
+    private var taskIdentifierInfo: TaskIdentifier {
+        return  getAssociatedObject(base, &taskIdentifierKey) ?? {
+            setRetainedAssociatedObject(base, &taskIdentifierKey, $0)
+            return $0
+        } (TaskIdentifier([:]))
+    }
+    
+    private var imageTask: DownloadTask? {
+        get { return getAssociatedObject(base, &imageTaskKey) }
+        set { setRetainedAssociatedObject(base, &imageTaskKey, newValue)}
+    }
+}
+
+
+private var backgroundTaskIdentifierKey: Void?
+private var backgroundImageTaskKey: Void?
+
+// MARK: Background Properties
+extension KingfisherWrapper where Base: UIButton {
+    
+    public func backgroundTaskIdentifier(for state: UIControl.State) -> Source.Identifier.Value? {
+        return backgroundTaskIdentifierInfo.value[state.rawValue]
+    }
+    
+    private func setBackgroundTaskIdentifier(_ identifier: Source.Identifier.Value?, for state: UIControl.State) {
+        backgroundTaskIdentifierInfo.value[state.rawValue] = identifier
+    }
+    
+    private var backgroundTaskIdentifierInfo: TaskIdentifier {
+        return  getAssociatedObject(base, &backgroundTaskIdentifierKey) ?? {
+            setRetainedAssociatedObject(base, &backgroundTaskIdentifierKey, $0)
+            return $0
+        } (TaskIdentifier([:]))
+    }
+    
+    private var backgroundImageTask: DownloadTask? {
+        get { return getAssociatedObject(base, &backgroundImageTaskKey) }
+        mutating set { setRetainedAssociatedObject(base, &backgroundImageTaskKey, newValue) }
+    }
+}
+#endif
+
+#endif

Pods/Kingfisher/Sources/Extensions/WKInterfaceImage+Kingfisher.swift

@@ -0,0 +1,204 @@
+//
+//  WKInterfaceImage+Kingfisher.swift
+//  Kingfisher
+//
+//  Created by Rodrigo Borges Soares on 04/05/18.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if canImport(WatchKit)
+
+import WatchKit
+
+extension KingfisherWrapper where Base: WKInterfaceImage {
+
+    // MARK: Setting Image
+
+    /// Sets an image to the image view with a source.
+    ///
+    /// - Parameters:
+    ///   - source: The `Source` object contains information about the image.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the requested source
+    /// Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with source: Source?,
+        placeholder: KFCrossPlatformImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        let options = KingfisherParsedOptionsInfo(KingfisherManager.shared.defaultOptions + (options ?? .empty))
+        return setImage(
+            with: source,
+            placeholder: placeholder,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler
+        )
+    }
+    
+    /// Sets an image to the image view with a requested resource.
+    ///
+    /// - Parameters:
+    ///   - resource: The `Resource` object contains information about the image.
+    ///   - placeholder: A placeholder to show while retrieving the image from the given `resource`.
+    ///   - options: An options set to define image setting behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called.
+    ///   - completionHandler: Called when the image retrieved and set finished.
+    /// - Returns: A task represents the image downloading.
+    ///
+    /// - Note:
+    ///
+    /// Internally, this method will use `KingfisherManager` to get the requested resource, from either cache
+    /// or network. Since this method will perform UI changes, you must call it from the main thread.
+    /// Both `progressBlock` and `completionHandler` will be also executed in the main thread.
+    ///
+    @discardableResult
+    public func setImage(
+        with resource: Resource?,
+        placeholder: KFCrossPlatformImage? = nil,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        return setImage(
+            with: resource?.convertToSource(),
+            placeholder: placeholder,
+            options: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler)
+    }
+
+    func setImage(
+        with source: Source?,
+        placeholder: KFCrossPlatformImage? = nil,
+        parsedOptions: KingfisherParsedOptionsInfo,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        var mutatingSelf = self
+        guard let source = source else {
+            base.setImage(placeholder)
+            mutatingSelf.taskIdentifier = nil
+            completionHandler?(.failure(KingfisherError.imageSettingError(reason: .emptySource)))
+            return nil
+        }
+
+        var options = parsedOptions
+        if !options.keepCurrentImageWhileLoading {
+            base.setImage(placeholder)
+        }
+
+        let issuedIdentifier = Source.Identifier.next()
+        mutatingSelf.taskIdentifier = issuedIdentifier
+
+        if let block = progressBlock {
+            options.onDataReceived = (options.onDataReceived ?? []) + [ImageLoadingProgressSideEffect(block)]
+        }
+
+        let task = KingfisherManager.shared.retrieveImage(
+            with: source,
+            options: options,
+            downloadTaskUpdated: { mutatingSelf.imageTask = $0 },
+            progressiveImageSetter: { self.base.setImage($0) },
+            referenceTaskIdentifierChecker: { issuedIdentifier == self.taskIdentifier },
+            completionHandler: { result in
+                CallbackQueue.mainCurrentOrAsync.execute {
+                    guard issuedIdentifier == self.taskIdentifier else {
+                        let reason: KingfisherError.ImageSettingErrorReason
+                        do {
+                            let value = try result.get()
+                            reason = .notCurrentSourceTask(result: value, error: nil, source: source)
+                        } catch {
+                            reason = .notCurrentSourceTask(result: nil, error: error, source: source)
+                        }
+                        let error = KingfisherError.imageSettingError(reason: reason)
+                        completionHandler?(.failure(error))
+                        return
+                    }
+
+                    mutatingSelf.imageTask = nil
+                    mutatingSelf.taskIdentifier = nil
+
+                    switch result {
+                    case .success(let value):
+                        self.base.setImage(value.image)
+                        completionHandler?(result)
+
+                    case .failure:
+                        if let image = options.onFailureImage {
+                            self.base.setImage(image)
+                        }
+                        completionHandler?(result)
+                    }
+                }
+            }
+        )
+
+        mutatingSelf.imageTask = task
+        return task
+    }
+
+    // MARK: Cancelling Image
+
+    /// Cancel the image download task bounded to the image view if it is running.
+    /// Nothing will happen if the downloading has already finished.
+    public func cancelDownloadTask() {
+        imageTask?.cancel()
+    }
+}
+
+private var taskIdentifierKey: Void?
+private var imageTaskKey: Void?
+
+// MARK: Properties
+extension KingfisherWrapper where Base: WKInterfaceImage {
+    
+    public private(set) var taskIdentifier: Source.Identifier.Value? {
+        get {
+            let box: Box<Source.Identifier.Value>? = getAssociatedObject(base, &taskIdentifierKey)
+            return box?.value
+        }
+        set {
+            let box = newValue.map { Box($0) }
+            setRetainedAssociatedObject(base, &taskIdentifierKey, box)
+        }
+    }
+
+    private var imageTask: DownloadTask? {
+        get { return getAssociatedObject(base, &imageTaskKey) }
+        set { setRetainedAssociatedObject(base, &imageTaskKey, newValue)}
+    }
+}
+#endif

Pods/Kingfisher/Sources/General/ImageSource/AVAssetImageDataProvider.swift

@@ -0,0 +1,151 @@
+//
+//  AVAssetImageDataProvider.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2020/08/09.
+//
+//  Copyright (c) 2020 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if !os(watchOS)
+
+import Foundation
+import AVKit
+
+#if canImport(MobileCoreServices)
+import MobileCoreServices
+#else
+import CoreServices
+#endif
+
+/// A data provider to provide thumbnail data from a given AVKit asset.
+public struct AVAssetImageDataProvider: ImageDataProvider {
+
+    /// The possible error might be caused by the `AVAssetImageDataProvider`.
+    /// - userCancelled: The data provider process is cancelled.
+    /// - invalidImage: The retrieved image is invalid.
+    public enum AVAssetImageDataProviderError: Error {
+        case userCancelled
+        case invalidImage(_ image: CGImage?)
+    }
+
+    /// The asset image generator bound to `self`.
+    public let assetImageGenerator: AVAssetImageGenerator
+
+    /// The time at which the image should be generate in the asset.
+    public let time: CMTime
+
+    private var internalKey: String {
+        guard let url = (assetImageGenerator.asset as? AVURLAsset)?.url else {
+            return UUID().uuidString
+        }
+        return url.cacheKey
+    }
+
+    /// The cache key used by `self`.
+    public var cacheKey: String {
+        return "\(internalKey)_\(time.seconds)"
+    }
+
+    /// Creates an asset image data provider.
+    /// - Parameters:
+    ///   - assetImageGenerator: The asset image generator controls data providing behaviors.
+    ///   - time: At which time in the asset the image should be generated.
+    public init(assetImageGenerator: AVAssetImageGenerator, time: CMTime) {
+        self.assetImageGenerator = assetImageGenerator
+        self.time = time
+    }
+
+    /// Creates an asset image data provider.
+    /// - Parameters:
+    ///   - assetURL: The URL of asset for providing image data.
+    ///   - time: At which time in the asset the image should be generated.
+    ///
+    /// This method uses `assetURL` to create an `AVAssetImageGenerator` object and calls
+    /// the `init(assetImageGenerator:time:)` initializer.
+    ///
+    public init(assetURL: URL, time: CMTime) {
+        let asset = AVAsset(url: assetURL)
+        let generator = AVAssetImageGenerator(asset: asset)
+        generator.appliesPreferredTrackTransform = true
+        self.init(assetImageGenerator: generator, time: time)
+    }
+
+    /// Creates an asset image data provider.
+    ///
+    /// - Parameters:
+    ///   - assetURL: The URL of asset for providing image data.
+    ///   - seconds: At which time in seconds in the asset the image should be generated.
+    ///
+    /// This method uses `assetURL` to create an `AVAssetImageGenerator` object, uses `seconds` to create a `CMTime`,
+    /// and calls the `init(assetImageGenerator:time:)` initializer.
+    ///
+    public init(assetURL: URL, seconds: TimeInterval) {
+        let time = CMTime(seconds: seconds, preferredTimescale: 600)
+        self.init(assetURL: assetURL, time: time)
+    }
+
+    public func data(handler: @escaping (Result<Data, Error>) -> Void) {
+        assetImageGenerator.generateCGImagesAsynchronously(forTimes: [NSValue(time: time)]) {
+            (requestedTime, image, imageTime, result, error) in
+            if let error = error {
+                handler(.failure(error))
+                return
+            }
+
+            if result == .cancelled {
+                handler(.failure(AVAssetImageDataProviderError.userCancelled))
+                return
+            }
+
+            guard let cgImage = image, let data = cgImage.jpegData else {
+                handler(.failure(AVAssetImageDataProviderError.invalidImage(image)))
+                return
+            }
+
+            handler(.success(data))
+        }
+    }
+}
+
+extension CGImage {
+    var jpegData: Data? {
+        guard let mutableData = CFDataCreateMutable(nil, 0) else {
+            return nil
+        }
+#if os(visionOS)
+        guard let destination = CGImageDestinationCreateWithData(
+            mutableData, UTType.jpeg.identifier as CFString , 1, nil
+        ) else {
+            return nil
+        }
+#else
+        guard let destination = CGImageDestinationCreateWithData(mutableData, kUTTypeJPEG, 1, nil) else {
+            return nil
+        }
+#endif
+        
+        CGImageDestinationAddImage(destination, self, nil)
+        guard CGImageDestinationFinalize(destination) else { return nil }
+        return mutableData as Data
+    }
+}
+
+#endif

Pods/Kingfisher/Sources/General/ImageSource/ImageDataProvider.swift

@@ -0,0 +1,190 @@
+//
+//  ImageDataProvider.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2018/11/13.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+/// Represents a data provider to provide image data to Kingfisher when setting with
+/// `Source.provider` source. Compared to `Source.network` member, it gives a chance
+/// to load some image data in your own way, as long as you can provide the data
+/// representation for the image.
+public protocol ImageDataProvider {
+    
+    /// The key used in cache.
+    var cacheKey: String { get }
+    
+    /// Provides the data which represents image. Kingfisher uses the data you pass in the
+    /// handler to process images and caches it for later use.
+    ///
+    /// - Parameter handler: The handler you should call when you prepared your data.
+    ///                      If the data is loaded successfully, call the handler with
+    ///                      a `.success` with the data associated. Otherwise, call it
+    ///                      with a `.failure` and pass the error.
+    ///
+    /// - Note:
+    /// If the `handler` is called with a `.failure` with error, a `dataProviderError` of
+    /// `ImageSettingErrorReason` will be finally thrown out to you as the `KingfisherError`
+    /// from the framework.
+    func data(handler: @escaping (Result<Data, Error>) -> Void)
+
+    /// The content URL represents this provider, if exists.
+    var contentURL: URL? { get }
+}
+
+public extension ImageDataProvider {
+    var contentURL: URL? { return nil }
+    func convertToSource() -> Source {
+        .provider(self)
+    }
+}
+
+/// Represents an image data provider for loading from a local file URL on disk.
+/// Uses this type for adding a disk image to Kingfisher. Compared to loading it
+/// directly, you can get benefit of using Kingfisher's extension methods, as well
+/// as applying `ImageProcessor`s and storing the image to `ImageCache` of Kingfisher.
+public struct LocalFileImageDataProvider: ImageDataProvider {
+
+    // MARK: Public Properties
+
+    /// The file URL from which the image be loaded.
+    public let fileURL: URL
+    private let loadingQueue: ExecutionQueue
+
+    // MARK: Initializers
+
+    /// Creates an image data provider by supplying the target local file URL.
+    ///
+    /// - Parameters:
+    ///   - fileURL: The file URL from which the image be loaded.
+    ///   - cacheKey: The key is used for caching the image data. By default,
+    ///               the `absoluteString` of `fileURL` is used.
+    ///   - loadingQueue: The queue where the file loading should happen. By default, the dispatch queue of
+    ///                   `.global(qos: .userInitiated)` will be used.
+    public init(
+        fileURL: URL,
+        cacheKey: String? = nil,
+        loadingQueue: ExecutionQueue = .dispatch(DispatchQueue.global(qos: .userInitiated))
+    ) {
+        self.fileURL = fileURL
+        self.cacheKey = cacheKey ?? fileURL.localFileCacheKey
+        self.loadingQueue = loadingQueue
+    }
+
+    // MARK: Protocol Conforming
+
+    /// The key used in cache.
+    public var cacheKey: String
+
+    public func data(handler:@escaping (Result<Data, Error>) -> Void) {
+        loadingQueue.execute {
+            handler(Result(catching: { try Data(contentsOf: fileURL) }))
+        }
+    }
+    
+    #if swift(>=5.5)
+    #if canImport(_Concurrency)
+    @available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
+    public var data: Data {
+        get async throws {
+            try await withCheckedThrowingContinuation { continuation in
+                loadingQueue.execute {
+                    do {
+                        let data = try Data(contentsOf: fileURL)
+                        continuation.resume(returning: data)
+                    } catch {
+                        continuation.resume(throwing: error)
+                    }
+                }
+            }
+        }
+    }
+    #endif
+    #endif
+
+    /// The URL of the local file on the disk.
+    public var contentURL: URL? {
+        return fileURL
+    }
+}
+
+/// Represents an image data provider for loading image from a given Base64 encoded string.
+public struct Base64ImageDataProvider: ImageDataProvider {
+
+    // MARK: Public Properties
+    /// The encoded Base64 string for the image.
+    public let base64String: String
+
+    // MARK: Initializers
+
+    /// Creates an image data provider by supplying the Base64 encoded string.
+    ///
+    /// - Parameters:
+    ///   - base64String: The Base64 encoded string for an image.
+    ///   - cacheKey: The key is used for caching the image data. You need a different key for any different image.
+    public init(base64String: String, cacheKey: String) {
+        self.base64String = base64String
+        self.cacheKey = cacheKey
+    }
+
+    // MARK: Protocol Conforming
+
+    /// The key used in cache.
+    public var cacheKey: String
+
+    public func data(handler: (Result<Data, Error>) -> Void) {
+        let data = Data(base64Encoded: base64String)!
+        handler(.success(data))
+    }
+}
+
+/// Represents an image data provider for a raw data object.
+public struct RawImageDataProvider: ImageDataProvider {
+
+    // MARK: Public Properties
+
+    /// The raw data object to provide to Kingfisher image loader.
+    public let data: Data
+
+    // MARK: Initializers
+
+    /// Creates an image data provider by the given raw `data` value and a `cacheKey` be used in Kingfisher cache.
+    ///
+    /// - Parameters:
+    ///   - data: The raw data reprensents an image.
+    ///   - cacheKey: The key is used for caching the image data. You need a different key for any different image.
+    public init(data: Data, cacheKey: String) {
+        self.data = data
+        self.cacheKey = cacheKey
+    }
+
+    // MARK: Protocol Conforming
+    
+    /// The key used in cache.
+    public var cacheKey: String
+
+    public func data(handler: @escaping (Result<Data, Error>) -> Void) {
+        handler(.success(data))
+    }
+}

Pods/Kingfisher/Sources/General/ImageSource/Resource.swift

@@ -0,0 +1,121 @@
+//
+//  Resource.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 15/4/6.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+/// Represents an image resource at a certain url and a given cache key.
+/// Kingfisher will use a `Resource` to download a resource from network and cache it with the cache key when
+/// using `Source.network` as its image setting source.
+public protocol Resource {
+    
+    /// The key used in cache.
+    var cacheKey: String { get }
+    
+    /// The target image URL.
+    var downloadURL: URL { get }
+}
+
+extension Resource {
+
+    /// Converts `self` to a valid `Source` based on its `downloadURL` scheme. A `.provider` with
+    /// `LocalFileImageDataProvider` associated will be returned if the URL points to a local file. Otherwise,
+    /// `.network` is returned.
+    public func convertToSource(overrideCacheKey: String? = nil) -> Source {
+        let key = overrideCacheKey ?? cacheKey
+        return downloadURL.isFileURL ?
+            .provider(LocalFileImageDataProvider(fileURL: downloadURL, cacheKey: key)) :
+            .network(KF.ImageResource(downloadURL: downloadURL, cacheKey: key))
+    }
+}
+
+@available(*, deprecated, message: "This type conflicts with `GeneratedAssetSymbols.ImageResource` in Swift 5.9. Renamed to avoid issues in the future.", renamed: "KF.ImageResource")
+public typealias ImageResource = KF.ImageResource
+
+
+extension KF {
+    /// ImageResource is a simple combination of `downloadURL` and `cacheKey`.
+    /// When passed to image view set methods, Kingfisher will try to download the target
+    /// image from the `downloadURL`, and then store it with the `cacheKey` as the key in cache.
+    public struct ImageResource: Resource {
+
+        // MARK: - Initializers
+
+        /// Creates an image resource.
+        ///
+        /// - Parameters:
+        ///   - downloadURL: The target image URL from where the image can be downloaded.
+        ///   - cacheKey: The cache key. If `nil`, Kingfisher will use the `absoluteString` of `downloadURL` as the key.
+        ///               Default is `nil`.
+        public init(downloadURL: URL, cacheKey: String? = nil) {
+            self.downloadURL = downloadURL
+            self.cacheKey = cacheKey ?? downloadURL.cacheKey
+        }
+
+        // MARK: Protocol Conforming
+        
+        /// The key used in cache.
+        public let cacheKey: String
+
+        /// The target image URL.
+        public let downloadURL: URL
+    }
+}
+
+/// URL conforms to `Resource` in Kingfisher.
+/// The `absoluteString` of this URL is used as `cacheKey`. And the URL itself will be used as `downloadURL`.
+/// If you need customize the url and/or cache key, use `ImageResource` instead.
+extension URL: Resource {
+    public var cacheKey: String { return isFileURL ? localFileCacheKey : absoluteString }
+    public var downloadURL: URL { return self }
+}
+
+extension URL {
+    static let localFileCacheKeyPrefix = "kingfisher.local.cacheKey"
+    
+    // The special version of cache key for a local file on disk. Every time the app is reinstalled on the disk,
+    // the system assigns a new container folder to hold the .app (and the extensions, .appex) folder. So the URL for
+    // the same image in bundle might be different.
+    //
+    // This getter only uses the fixed part in the URL (until the bundle name folder) to provide a stable cache key
+    // for the image under the same path inside the bundle.
+    //
+    // See #1825 (https://github.com/onevcat/Kingfisher/issues/1825)
+    var localFileCacheKey: String {
+        var validComponents: [String] = []
+        for part in pathComponents.reversed() {
+            validComponents.append(part)
+            if part.hasSuffix(".app") || part.hasSuffix(".appex") {
+                break
+            }
+        }
+        let fixedPath = "\(Self.localFileCacheKeyPrefix)/\(validComponents.reversed().joined(separator: "/"))"
+        if let q = query {
+            return "\(fixedPath)?\(q)"
+        } else {
+            return fixedPath
+        }
+    }
+}

Pods/Kingfisher/Sources/General/ImageSource/Source.swift

@@ -0,0 +1,116 @@
+//
+//  Source.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2018/11/17.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+/// Represents an image setting source for Kingfisher methods.
+///
+/// A `Source` value indicates the way how the target image can be retrieved and cached.
+///
+/// - network: The target image should be got from network remotely. The associated `Resource`
+///            value defines detail information like image URL and cache key.
+/// - provider: The target image should be provided in a data format. Normally, it can be an image
+///             from local storage or in any other encoding format (like Base64).
+public enum Source {
+
+    /// Represents the source task identifier when setting an image to a view with extension methods.
+    public enum Identifier {
+
+        /// The underlying value type of source identifier.
+        public typealias Value = UInt
+        static private(set) var current: Value = 0
+        static func next() -> Value {
+            current += 1
+            return current
+        }
+    }
+
+    // MARK: Member Cases
+
+    /// The target image should be got from network remotely. The associated `Resource`
+    /// value defines detail information like image URL and cache key.
+    case network(Resource)
+    
+    /// The target image should be provided in a data format. Normally, it can be an image
+    /// from local storage or in any other encoding format (like Base64).
+    case provider(ImageDataProvider)
+
+    // MARK: Getting Properties
+
+    /// The cache key defined for this source value.
+    public var cacheKey: String {
+        switch self {
+        case .network(let resource): return resource.cacheKey
+        case .provider(let provider): return provider.cacheKey
+        }
+    }
+
+    /// The URL defined for this source value.
+    ///
+    /// For a `.network` source, it is the `downloadURL` of associated `Resource` instance.
+    /// For a `.provider` value, it is always `nil`.
+    public var url: URL? {
+        switch self {
+        case .network(let resource): return resource.downloadURL
+        case .provider(let provider): return provider.contentURL
+        }
+    }
+}
+
+extension Source: Hashable {
+    public static func == (lhs: Source, rhs: Source) -> Bool {
+        switch (lhs, rhs) {
+        case (.network(let r1), .network(let r2)):
+            return r1.cacheKey == r2.cacheKey && r1.downloadURL == r2.downloadURL
+        case (.provider(let p1), .provider(let p2)):
+            return p1.cacheKey == p2.cacheKey && p1.contentURL == p2.contentURL
+        case (.provider(_), .network(_)):
+            return false
+        case (.network(_), .provider(_)):
+            return false
+        }
+    }
+
+    public func hash(into hasher: inout Hasher) {
+        switch self {
+        case .network(let r):
+            hasher.combine(r.cacheKey)
+            hasher.combine(r.downloadURL)
+        case .provider(let p):
+            hasher.combine(p.cacheKey)
+            hasher.combine(p.contentURL)
+        }
+    }
+}
+
+extension Source {
+    var asResource: Resource? {
+        guard case .network(let resource) = self else {
+            return nil
+        }
+        return resource
+    }
+}

Pods/Kingfisher/Sources/General/KF.swift

@@ -0,0 +1,442 @@
+//
+//  KF.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2020/09/21.
+//
+//  Copyright (c) 2020 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if canImport(UIKit)
+import UIKit
+#endif
+
+#if canImport(CarPlay) && !targetEnvironment(macCatalyst)
+import CarPlay
+#endif
+
+#if canImport(AppKit) && !targetEnvironment(macCatalyst)
+import AppKit
+#endif
+
+#if canImport(WatchKit)
+import WatchKit
+#endif
+
+#if canImport(TVUIKit)
+import TVUIKit
+#endif
+
+/// A helper type to create image setting tasks in a builder pattern.
+/// Use methods in this type to create a `KF.Builder` instance and configure image tasks there.
+public enum KF {
+
+    /// Creates a builder for a given `Source`.
+    /// - Parameter source: The `Source` object defines data information from network or a data provider.
+    /// - Returns: A `KF.Builder` for future configuration. After configuring the builder, call `set(to:)`
+    ///            to start the image loading.
+    public static func source(_ source: Source?) -> KF.Builder {
+        Builder(source: source)
+    }
+
+    /// Creates a builder for a given `Resource`.
+    /// - Parameter resource: The `Resource` object defines data information like key or URL.
+    /// - Returns: A `KF.Builder` for future configuration. After configuring the builder, call `set(to:)`
+    ///            to start the image loading.
+    public static func resource(_ resource: Resource?) -> KF.Builder {
+        source(resource?.convertToSource())
+    }
+
+    /// Creates a builder for a given `URL` and an optional cache key.
+    /// - Parameters:
+    ///   - url: The URL where the image should be downloaded.
+    ///   - cacheKey: The key used to store the downloaded image in cache.
+    ///               If `nil`, the `absoluteString` of `url` is used as the cache key.
+    /// - Returns: A `KF.Builder` for future configuration. After configuring the builder, call `set(to:)`
+    ///            to start the image loading.
+    public static func url(_ url: URL?, cacheKey: String? = nil) -> KF.Builder {
+        source(url?.convertToSource(overrideCacheKey: cacheKey))
+    }
+
+    /// Creates a builder for a given `ImageDataProvider`.
+    /// - Parameter provider: The `ImageDataProvider` object contains information about the data.
+    /// - Returns: A `KF.Builder` for future configuration. After configuring the builder, call `set(to:)`
+    ///            to start the image loading.
+    public static func dataProvider(_ provider: ImageDataProvider?) -> KF.Builder {
+        source(provider?.convertToSource())
+    }
+
+    /// Creates a builder for some given raw data and a cache key.
+    /// - Parameters:
+    ///   - data: The data object from which the image should be created.
+    ///   - cacheKey: The key used to store the downloaded image in cache.
+    /// - Returns: A `KF.Builder` for future configuration. After configuring the builder, call `set(to:)`
+    ///            to start the image loading.
+    public static func data(_ data: Data?, cacheKey: String) -> KF.Builder {
+        if let data = data {
+            return dataProvider(RawImageDataProvider(data: data, cacheKey: cacheKey))
+        } else {
+            return dataProvider(nil)
+        }
+    }
+}
+
+
+extension KF {
+
+    /// A builder class to configure an image retrieving task and set it to a holder view or component.
+    public class Builder {
+        private let source: Source?
+
+        #if os(watchOS)
+        private var placeholder: KFCrossPlatformImage?
+        #else
+        private var placeholder: Placeholder?
+        #endif
+
+        public var options = KingfisherParsedOptionsInfo(KingfisherManager.shared.defaultOptions)
+
+        public let onFailureDelegate = Delegate<KingfisherError, Void>()
+        public let onSuccessDelegate = Delegate<RetrieveImageResult, Void>()
+        public let onProgressDelegate = Delegate<(Int64, Int64), Void>()
+
+        init(source: Source?) {
+            self.source = source
+        }
+
+        private var resultHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)? {
+            {
+                switch $0 {
+                case .success(let result):
+                    self.onSuccessDelegate(result)
+                case .failure(let error):
+                    self.onFailureDelegate(error)
+                }
+            }
+        }
+
+        private var progressBlock: DownloadProgressBlock {
+            { self.onProgressDelegate(($0, $1)) }
+        }
+    }
+}
+
+extension KF.Builder {
+    #if !os(watchOS)
+
+    /// Builds the image task request and sets it to an image view.
+    /// - Parameter imageView: The image view which loads the task and should be set with the image.
+    /// - Returns: A task represents the image downloading, if initialized.
+    ///            This value is `nil` if the image is being loaded from cache.
+    @discardableResult
+    public func set(to imageView: KFCrossPlatformImageView) -> DownloadTask? {
+        imageView.kf.setImage(
+            with: source,
+            placeholder: placeholder,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: resultHandler
+        )
+    }
+
+    /// Builds the image task request and sets it to an `NSTextAttachment` object.
+    /// - Parameters:
+    ///   - attachment: The text attachment object which loads the task and should be set with the image.
+    ///   - attributedView: The owner of the attributed string which this `NSTextAttachment` is added.
+    /// - Returns: A task represents the image downloading, if initialized.
+    ///            This value is `nil` if the image is being loaded from cache.
+    @discardableResult
+    public func set(to attachment: NSTextAttachment, attributedView: @autoclosure @escaping () -> KFCrossPlatformView) -> DownloadTask? {
+        let placeholderImage = placeholder as? KFCrossPlatformImage ?? nil
+        return attachment.kf.setImage(
+            with: source,
+            attributedView: attributedView,
+            placeholder: placeholderImage,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: resultHandler
+        )
+    }
+
+    #if canImport(UIKit)
+
+    /// Builds the image task request and sets it to a button.
+    /// - Parameters:
+    ///   - button: The button which loads the task and should be set with the image.
+    ///   - state: The button state to which the image should be set.
+    /// - Returns: A task represents the image downloading, if initialized.
+    ///            This value is `nil` if the image is being loaded from cache.
+    @discardableResult
+    public func set(to button: UIButton, for state: UIControl.State) -> DownloadTask? {
+        let placeholderImage = placeholder as? KFCrossPlatformImage ?? nil
+        return button.kf.setImage(
+            with: source,
+            for: state,
+            placeholder: placeholderImage,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: resultHandler
+        )
+    }
+
+    /// Builds the image task request and sets it to the background image for a button.
+    /// - Parameters:
+    ///   - button: The button which loads the task and should be set with the image.
+    ///   - state: The button state to which the image should be set.
+    /// - Returns: A task represents the image downloading, if initialized.
+    ///            This value is `nil` if the image is being loaded from cache.
+    @discardableResult
+    public func setBackground(to button: UIButton, for state: UIControl.State) -> DownloadTask? {
+        let placeholderImage = placeholder as? KFCrossPlatformImage ?? nil
+        return button.kf.setBackgroundImage(
+            with: source,
+            for: state,
+            placeholder: placeholderImage,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: resultHandler
+        )
+    }
+    #endif // end of canImport(UIKit)
+    
+    #if canImport(CarPlay) && !targetEnvironment(macCatalyst)
+    
+    /// Builds the image task request and sets it to the image for a list item.
+    /// - Parameters:
+    ///   - listItem: The list item which loads the task and should be set with the image.
+    /// - Returns: A task represents the image downloading, if initialized.
+    ///            This value is `nil` if the image is being loaded from cache.
+    @available(iOS 14.0, *)
+    @discardableResult
+    public func set(to listItem: CPListItem) -> DownloadTask? {
+        let placeholderImage = placeholder as? KFCrossPlatformImage ?? nil
+        return listItem.kf.setImage(
+            with: source,
+            placeholder: placeholderImage,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: resultHandler
+        )
+        
+    }
+    
+    #endif
+
+    #if canImport(AppKit) && !targetEnvironment(macCatalyst)
+    /// Builds the image task request and sets it to a button.
+    /// - Parameter button: The button which loads the task and should be set with the image.
+    /// - Returns: A task represents the image downloading, if initialized.
+    ///            This value is `nil` if the image is being loaded from cache.
+    @discardableResult
+    public func set(to button: NSButton) -> DownloadTask? {
+        let placeholderImage = placeholder as? KFCrossPlatformImage ?? nil
+        return button.kf.setImage(
+            with: source,
+            placeholder: placeholderImage,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: resultHandler
+        )
+    }
+
+    /// Builds the image task request and sets it to the alternative image for a button.
+    /// - Parameter button: The button which loads the task and should be set with the image.
+    /// - Returns: A task represents the image downloading, if initialized.
+    ///            This value is `nil` if the image is being loaded from cache.
+    @discardableResult
+    public func setAlternative(to button: NSButton) -> DownloadTask? {
+        let placeholderImage = placeholder as? KFCrossPlatformImage ?? nil
+        return button.kf.setAlternateImage(
+            with: source,
+            placeholder: placeholderImage,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: resultHandler
+        )
+    }
+    #endif // end of canImport(AppKit)
+    #endif // end of !os(watchOS)
+
+    #if canImport(WatchKit)
+    /// Builds the image task request and sets it to a `WKInterfaceImage` object.
+    /// - Parameter interfaceImage: The watch interface image which loads the task and should be set with the image.
+    /// - Returns: A task represents the image downloading, if initialized.
+    ///            This value is `nil` if the image is being loaded from cache.
+    @discardableResult
+    public func set(to interfaceImage: WKInterfaceImage) -> DownloadTask? {
+        return interfaceImage.kf.setImage(
+            with: source,
+            placeholder: placeholder,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: resultHandler
+        )
+    }
+    #endif // end of canImport(WatchKit)
+
+    #if canImport(TVUIKit)
+    /// Builds the image task request and sets it to a TV monogram view.
+    /// - Parameter monogramView: The monogram view which loads the task and should be set with the image.
+    /// - Returns: A task represents the image downloading, if initialized.
+    ///            This value is `nil` if the image is being loaded from cache.
+    @available(tvOS 12.0, *)
+    @discardableResult
+    public func set(to monogramView: TVMonogramView) -> DownloadTask? {
+        let placeholderImage = placeholder as? KFCrossPlatformImage ?? nil
+        return monogramView.kf.setImage(
+            with: source,
+            placeholder: placeholderImage,
+            parsedOptions: options,
+            progressBlock: progressBlock,
+            completionHandler: resultHandler
+        )
+    }
+    #endif // end of canImport(TVUIKit)
+}
+
+#if !os(watchOS)
+extension KF.Builder {
+    #if os(iOS) || os(tvOS) || os(visionOS)
+
+    /// Sets a placeholder which is used while retrieving the image.
+    /// - Parameter placeholder: A placeholder to show while retrieving the image from its source.
+    /// - Returns: A `KF.Builder` with changes applied.
+    public func placeholder(_ placeholder: Placeholder?) -> Self {
+        self.placeholder = placeholder
+        return self
+    }
+    #endif
+
+    /// Sets a placeholder image which is used while retrieving the image.
+    /// - Parameter placeholder: An image to show while retrieving the image from its source.
+    /// - Returns: A `KF.Builder` with changes applied.
+    public func placeholder(_ image: KFCrossPlatformImage?) -> Self {
+        self.placeholder = image
+        return self
+    }
+}
+#endif
+
+extension KF.Builder {
+
+    #if os(iOS) || os(tvOS) || os(visionOS)
+    /// Sets the transition for the image task.
+    /// - Parameter transition: The desired transition effect when setting the image to image view.
+    /// - Returns: A `KF.Builder` with changes applied.
+    ///
+    /// Kingfisher will use the `transition` to animate the image in if it is downloaded from web.
+    /// The transition will not happen when the
+    /// image is retrieved from either memory or disk cache by default. If you need to do the transition even when
+    /// the image being retrieved from cache, also call `forceRefresh()` on the returned `KF.Builder`.
+    public func transition(_ transition: ImageTransition) -> Self {
+        options.transition = transition
+        return self
+    }
+
+    /// Sets a fade transition for the image task.
+    /// - Parameter duration: The duration of the fade transition.
+    /// - Returns: A `KF.Builder` with changes applied.
+    ///
+    /// Kingfisher will use the fade transition to animate the image in if it is downloaded from web.
+    /// The transition will not happen when the
+    /// image is retrieved from either memory or disk cache by default. If you need to do the transition even when
+    /// the image being retrieved from cache, also call `forceRefresh()` on the returned `KF.Builder`.
+    public func fade(duration: TimeInterval) -> Self {
+        options.transition = .fade(duration)
+        return self
+    }
+    #endif
+
+    /// Sets whether keeping the existing image of image view while setting another image to it.
+    /// - Parameter enabled: Whether the existing image should be kept.
+    /// - Returns: A `KF.Builder` with changes applied.
+    ///
+    /// By setting this option, the placeholder image parameter of image view extension method
+    /// will be ignored and the current image will be kept while loading or downloading the new image.
+    ///
+    public func keepCurrentImageWhileLoading(_ enabled: Bool = true) -> Self {
+        options.keepCurrentImageWhileLoading = enabled
+        return self
+    }
+
+    /// Sets whether only the first frame from an animated image file should be loaded as a single image.
+    /// - Parameter enabled: Whether the only the first frame should be loaded.
+    /// - Returns: A `KF.Builder` with changes applied.
+    ///
+    /// Loading an animated images may take too much memory. It will be useful when you want to display a
+    /// static preview of the first frame from an animated image.
+    ///
+    /// This option will be ignored if the target image is not animated image data.
+    ///
+    public func onlyLoadFirstFrame(_ enabled: Bool = true) -> Self {
+        options.onlyLoadFirstFrame = enabled
+        return self
+    }
+
+    /// Enables progressive image loading with a specified `ImageProgressive` setting to process the
+    /// progressive JPEG data and display it in a progressive way.
+    /// - Parameter progressive: The progressive settings which is used while loading.
+    /// - Returns: A `KF.Builder` with changes applied.
+    public func progressiveJPEG(_ progressive: ImageProgressive? = .init()) -> Self {
+        options.progressiveJPEG = progressive
+        return self
+    }
+}
+
+// MARK: - Deprecated
+extension KF.Builder {
+    /// Starts the loading process of `self` immediately.
+    ///
+    /// By default, a `KFImage` will not load its source until the `onAppear` is called. This is a lazily loading
+    /// behavior and provides better performance. However, when you refresh the view, the lazy loading also causes a
+    /// flickering since the loading does not happen immediately. Call this method if you want to start the load at once
+    /// could help avoiding the flickering, with some performance trade-off.
+    ///
+    /// - Deprecated: This is not necessary anymore since `@StateObject` is used for holding the image data.
+    /// It does nothing now and please just remove it.
+    ///
+    /// - Returns: The `Self` value with changes applied.
+    @available(*, deprecated, message: "This is not necessary anymore since `@StateObject` is used. It does nothing now and please just remove it.")
+    public func loadImmediately(_ start: Bool = true) -> Self {
+        return self
+    }
+}
+
+// MARK: - Redirect Handler
+extension KF {
+
+    /// Represents the detail information when a task redirect happens. It is wrapping necessary information for a
+    /// `ImageDownloadRedirectHandler`. See that protocol for more information.
+    public struct RedirectPayload {
+
+        /// The related session data task when the redirect happens. It is
+        /// the current `SessionDataTask` which triggers this redirect.
+        public let task: SessionDataTask
+
+        /// The response received during redirection.
+        public let response: HTTPURLResponse
+
+        /// The request for redirection which can be modified.
+        public let newRequest: URLRequest
+
+        /// A closure for being called with modified request.
+        public let completionHandler: (URLRequest?) -> Void
+    }
+}

Pods/Kingfisher/Sources/General/KFOptionsSetter.swift

@@ -0,0 +1,711 @@
+//
+//  KFOptionsSetter.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2020/12/22.
+//
+//  Copyright (c) 2020 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+import CoreGraphics
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+public protocol KFOptionSetter {
+    var options: KingfisherParsedOptionsInfo { get nonmutating set }
+
+    var onFailureDelegate: Delegate<KingfisherError, Void> { get }
+    var onSuccessDelegate: Delegate<RetrieveImageResult, Void> { get }
+    var onProgressDelegate: Delegate<(Int64, Int64), Void> { get }
+
+    var delegateObserver: AnyObject { get }
+}
+
+extension KF.Builder: KFOptionSetter {
+    public var delegateObserver: AnyObject { self }
+}
+
+// MARK: - Life cycles
+extension KFOptionSetter {
+    /// Sets the progress block to current builder.
+    /// - Parameter block: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called. If `block` is `nil`, the callback
+    ///                    will be reset.
+    /// - Returns: A `Self` value with changes applied.
+    public func onProgress(_ block: DownloadProgressBlock?) -> Self {
+        onProgressDelegate.delegate(on: delegateObserver) { (observer, result) in
+            block?(result.0, result.1)
+        }
+        return self
+    }
+
+    /// Sets the the done block to current builder.
+    /// - Parameter block: Called when the image task successfully completes and the the image set is done. If `block`
+    ///                    is `nil`, the callback will be reset.
+    /// - Returns: A `KF.Builder` with changes applied.
+    public func onSuccess(_ block: ((RetrieveImageResult) -> Void)?) -> Self {
+        onSuccessDelegate.delegate(on: delegateObserver) { (observer, result) in
+            block?(result)
+        }
+        return self
+    }
+
+    /// Sets the catch block to current builder.
+    /// - Parameter block: Called when an error happens during the image task. If `block`
+    ///                    is `nil`, the callback will be reset.
+    /// - Returns: A `KF.Builder` with changes applied.
+    public func onFailure(_ block: ((KingfisherError) -> Void)?) -> Self {
+        onFailureDelegate.delegate(on: delegateObserver) { (observer, error) in
+            block?(error)
+        }
+        return self
+    }
+}
+
+// MARK: - Basic options settings.
+extension KFOptionSetter {
+    /// Sets the target image cache for this task.
+    /// - Parameter cache: The target cache is about to be used for the task.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// Kingfisher will use the associated `ImageCache` object when handling related operations,
+    /// including trying to retrieve the cached images and store the downloaded image to it.
+    ///
+    public func targetCache(_ cache: ImageCache) -> Self {
+        options.targetCache = cache
+        return self
+    }
+
+    /// Sets the target image cache to store the original downloaded image for this task.
+    /// - Parameter cache: The target cache is about to be used for storing the original downloaded image from the task.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// The `ImageCache` for storing and retrieving original images. If `originalCache` is
+    /// contained in the options, it will be preferred for storing and retrieving original images.
+    /// If there is no `.originalCache` in the options, `.targetCache` will be used to store original images.
+    ///
+    /// When using KingfisherManager to download and store an image, if `cacheOriginalImage` is
+    /// applied in the option, the original image will be stored to this `originalCache`. At the
+    /// same time, if a requested final image (with processor applied) cannot be found in `targetCache`,
+    /// Kingfisher will try to search the original image to check whether it is already there. If found,
+    /// it will be used and applied with the given processor. It is an optimization for not downloading
+    /// the same image for multiple times.
+    ///
+    public func originalCache(_ cache: ImageCache) -> Self {
+        options.originalCache = cache
+        return self
+    }
+
+    /// Sets the downloader used to perform the image download task.
+    /// - Parameter downloader: The downloader which is about to be used for downloading.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// Kingfisher will use the set `ImageDownloader` object to download the requested images.
+    public func downloader(_ downloader: ImageDownloader) -> Self {
+        options.downloader = downloader
+        return self
+    }
+
+    /// Sets the download priority for the image task.
+    /// - Parameter priority: The download priority of image download task.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// The `priority` value will be set as the priority of the image download task. The value for it should be
+    /// between 0.0~1.0. You can choose a value between `URLSessionTask.defaultPriority`, `URLSessionTask.lowPriority`
+    /// or `URLSessionTask.highPriority`. If this option not set, the default value (`URLSessionTask.defaultPriority`)
+    /// will be used.
+    public func downloadPriority(_ priority: Float) -> Self {
+        options.downloadPriority = priority
+        return self
+    }
+
+    /// Sets whether Kingfisher should ignore the cache and try to start a download task for the image source.
+    /// - Parameter enabled: Enable the force refresh or not.
+    /// - Returns: A `Self` value with changes applied.
+    public func forceRefresh(_ enabled: Bool = true) -> Self {
+        options.forceRefresh = enabled
+        return self
+    }
+
+    /// Sets whether Kingfisher should try to retrieve the image from memory cache first. If not found, it ignores the
+    /// disk cache and starts a download task for the image source.
+    /// - Parameter enabled: Enable the memory-only cache searching or not.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// This is useful when you want to display a changeable image behind the same url at the same app session, while
+    /// avoiding download it for multiple times.
+    public func fromMemoryCacheOrRefresh(_ enabled: Bool = true) -> Self {
+        options.fromMemoryCacheOrRefresh = enabled
+        return self
+    }
+
+    /// Sets whether the image should only be cached in memory but not in disk.
+    /// - Parameter enabled: Whether the image should be only cache in memory or not.
+    /// - Returns: A `Self` value with changes applied.
+    public func cacheMemoryOnly(_ enabled: Bool = true) -> Self {
+        options.cacheMemoryOnly = enabled
+        return self
+    }
+
+    /// Sets whether Kingfisher should wait for caching operation to be completed before calling the
+    /// `onSuccess` or `onFailure` block.
+    /// - Parameter enabled: Whether Kingfisher should wait for caching operation.
+    /// - Returns: A `Self` value with changes applied.
+    public func waitForCache(_ enabled: Bool = true) -> Self {
+        options.waitForCache = enabled
+        return self
+    }
+
+    /// Sets whether Kingfisher should only try to retrieve the image from cache, but not from network.
+    /// - Parameter enabled: Whether Kingfisher should only try to retrieve the image from cache.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// If the image is not in cache, the image retrieving will fail with the
+    /// `KingfisherError.cacheError` with `.imageNotExisting` as its reason.
+    public func onlyFromCache(_ enabled: Bool = true) -> Self {
+        options.onlyFromCache = enabled
+        return self
+    }
+
+    /// Sets whether the image should be decoded in a background thread before using.
+    /// - Parameter enabled: Whether the image should be decoded in a background thread before using.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// Setting to `true` will decode the downloaded image data and do a off-screen rendering to extract pixel
+    /// information in background. This can speed up display, but will cost more time and memory to prepare the image
+    /// for using.
+    public func backgroundDecode(_ enabled: Bool = true) -> Self {
+        options.backgroundDecode = enabled
+        return self
+    }
+
+    /// Sets the callback queue which is used as the target queue of dispatch callbacks when retrieving images from
+    ///  cache. If not set, Kingfisher will use main queue for callbacks.
+    /// - Parameter queue: The target queue which the cache retrieving callback will be invoked on.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// - Note:
+    /// This option does not affect the callbacks for UI related extension methods or `KFImage` result handlers.
+    /// You will always get the callbacks called from main queue.
+    public func callbackQueue(_ queue: CallbackQueue) -> Self {
+        options.callbackQueue = queue
+        return self
+    }
+
+    /// Sets the scale factor value when converting retrieved data to an image.
+    /// - Parameter factor: The scale factor value.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// Specify the image scale, instead of your screen scale. You may need to set the correct scale when you dealing
+    /// with 2x or 3x retina images. Otherwise, Kingfisher will convert the data to image object at `scale` 1.0.
+    ///
+    public func scaleFactor(_ factor: CGFloat) -> Self {
+        options.scaleFactor = factor
+        return self
+    }
+
+    /// Sets whether the original image should be cached even when the original image has been processed by any other
+    /// `ImageProcessor`s.
+    /// - Parameter enabled: Whether the original image should be cached.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// If set and an `ImageProcessor` is used, Kingfisher will try to cache both the final result and original
+    /// image. Kingfisher will have a chance to use the original image when another processor is applied to the same
+    /// resource, instead of downloading it again. You can use `.originalCache` to specify a cache or the original
+    /// images if necessary.
+    ///
+    /// The original image will be only cached to disk storage.
+    ///
+    public func cacheOriginalImage(_ enabled: Bool = true) -> Self {
+        options.cacheOriginalImage = enabled
+        return self
+    }
+
+    /// Sets writing options for an original image on a first write
+    /// - Parameter writingOptions: Options to control the writing of data to a disk storage.
+    /// - Returns: A `Self` value with changes applied.
+    /// If set, options will be passed the store operation for a new files.
+    ///
+    /// This is useful if you want to implement file enctyption on first write - eg [.completeFileProtection]
+    ///
+    public func diskStoreWriteOptions(_ writingOptions: Data.WritingOptions) -> Self {
+        options.diskStoreWriteOptions = writingOptions
+        return self
+    }
+
+    /// Sets whether the disk storage loading should happen in the same calling queue.
+    /// - Parameter enabled: Whether the disk storage loading should happen in the same calling queue.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// By default, disk storage file loading
+    /// happens in its own queue with an asynchronous dispatch behavior. Although it provides better non-blocking disk
+    /// loading performance, it also causes a flickering when you reload an image from disk, if the image view already
+    /// has an image set.
+    ///
+    /// Set this options will stop that flickering by keeping all loading in the same queue (typically the UI queue
+    /// if you are using Kingfisher's extension methods to set an image), with a tradeoff of loading performance.
+    ///
+    public func loadDiskFileSynchronously(_ enabled: Bool = true) -> Self {
+        options.loadDiskFileSynchronously = enabled
+        return self
+    }
+
+    /// Sets a queue on which the image processing should happen.
+    /// - Parameter queue: The queue on which the image processing should happen.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// By default, Kingfisher uses a pre-defined serial
+    /// queue to process images. Use this option to change this behavior. For example, specify a `.mainCurrentOrAsync`
+    /// to let the image be processed in main queue to prevent a possible flickering (but with a possibility of
+    /// blocking the UI, especially if the processor needs a lot of time to run).
+    public func processingQueue(_ queue: CallbackQueue?) -> Self {
+        options.processingQueue = queue
+        return self
+    }
+
+    /// Sets the alternative sources that will be used when loading of the original input `Source` fails.
+    /// - Parameter sources: The alternative sources will be used.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// Values of the `sources` array will be used to start a new image loading task if the previous task
+    /// fails due to an error. The image source loading process will stop as soon as a source is loaded successfully.
+    /// If all `sources` are used but the loading is still failing, an `imageSettingError` with
+    /// `alternativeSourcesExhausted` as its reason will be given out in the `catch` block.
+    ///
+    /// This is useful if you want to implement a fallback solution for setting image.
+    ///
+    /// User cancellation will not trigger the alternative source loading.
+    public func alternativeSources(_ sources: [Source]?) -> Self {
+        options.alternativeSources = sources
+        return self
+    }
+
+    /// Sets a retry strategy that will be used when something gets wrong during the image retrieving.
+    /// - Parameter strategy: The provided strategy to define how the retrying should happen.
+    /// - Returns: A `Self` value with changes applied.
+    public func retry(_ strategy: RetryStrategy?) -> Self {
+        options.retryStrategy = strategy
+        return self
+    }
+
+    /// Sets a retry strategy with a max retry count and retrying interval.
+    /// - Parameters:
+    ///   - maxCount: The maximum count before the retry stops.
+    ///   - interval: The time interval between each retry attempt.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// This defines the simplest retry strategy, which retry a failing request for several times, with some certain
+    /// interval between each time. For example, `.retry(maxCount: 3, interval: .second(3))` means attempt for at most
+    /// three times, and wait for 3 seconds if a previous retry attempt fails, then start a new attempt.
+    public func retry(maxCount: Int, interval: DelayRetryStrategy.Interval = .seconds(3)) -> Self {
+        let strategy = DelayRetryStrategy(maxRetryCount: maxCount, retryInterval: interval)
+        options.retryStrategy = strategy
+        return self
+    }
+
+    /// Sets the `Source` should be loaded when user enables Low Data Mode and the original source fails with an
+    /// `NSURLErrorNetworkUnavailableReason.constrained` error.
+    /// - Parameter source: The `Source` will be loaded under low data mode.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// When this option is set, the
+    /// `allowsConstrainedNetworkAccess` property of the request for the original source will be set to `false` and the
+    /// `Source` in associated value will be used to retrieve the image for low data mode. Usually, you can provide a
+    /// low-resolution version of your image or a local image provider to display a placeholder.
+    ///
+    /// If not set or the `source` is `nil`, the device Low Data Mode will be ignored and the original source will
+    /// be loaded following the system default behavior, in a normal way.
+    public func lowDataModeSource(_ source: Source?) -> Self {
+        options.lowDataModeSource = source
+        return self
+    }
+
+    /// Sets whether the image setting for an image view should happen with transition even when retrieved from cache.
+    /// - Parameter enabled: Enable the force transition or not.
+    /// - Returns: A `Self` with changes applied.
+    public func forceTransition(_ enabled: Bool = true) -> Self {
+        options.forceTransition = enabled
+        return self
+    }
+
+    /// Sets the image that will be used if an image retrieving task fails.
+    /// - Parameter image: The image that will be used when something goes wrong.
+    /// - Returns: A `Self` with changes applied.
+    ///
+    /// If set and an image retrieving error occurred Kingfisher will set provided image (or empty)
+    /// in place of requested one. It's useful when you don't want to show placeholder
+    /// during loading time but wants to use some default image when requests will be failed.
+    ///
+    public func onFailureImage(_ image: KFCrossPlatformImage?) -> Self {
+        options.onFailureImage = .some(image)
+        return self
+    }
+}
+
+// MARK: - Request Modifier
+extension KFOptionSetter {
+    /// Sets an `ImageDownloadRequestModifier` to change the image download request before it being sent.
+    /// - Parameter modifier: The modifier will be used to change the request before it being sent.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// This is the last chance you can modify the image download request. You can modify the request for some
+    /// customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url mapping.
+    ///
+    public func requestModifier(_ modifier: AsyncImageDownloadRequestModifier) -> Self {
+        options.requestModifier = modifier
+        return self
+    }
+
+    /// Sets a block to change the image download request before it being sent.
+    /// - Parameter modifyBlock: The modifying block will be called to change the request before it being sent.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// This is the last chance you can modify the image download request. You can modify the request for some
+    /// customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url mapping.
+    ///
+    public func requestModifier(_ modifyBlock: @escaping (inout URLRequest) -> Void) -> Self {
+        options.requestModifier = AnyModifier { r -> URLRequest? in
+            var request = r
+            modifyBlock(&request)
+            return request
+        }
+        return self
+    }
+}
+
+// MARK: - Redirect Handler
+extension KFOptionSetter {
+    /// The `ImageDownloadRedirectHandler` argument will be used to change the request before redirection.
+    /// This is the possibility you can modify the image download request during redirect. You can modify the request for
+    /// some customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url
+    /// mapping.
+    /// The original redirection request will be sent without any modification by default.
+    /// - Parameter handler: The handler will be used for redirection.
+    /// - Returns: A `Self` value with changes applied.
+    public func redirectHandler(_ handler: ImageDownloadRedirectHandler) -> Self {
+        options.redirectHandler = handler
+        return self
+    }
+
+    /// The `block` will be used to change the request before redirection.
+    /// This is the possibility you can modify the image download request during redirect. You can modify the request for
+    /// some customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url
+    /// mapping.
+    /// The original redirection request will be sent without any modification by default.
+    /// - Parameter block: The block will be used for redirection.
+    /// - Returns: A `Self` value with changes applied.
+    public func redirectHandler(_ block: @escaping (KF.RedirectPayload) -> Void) -> Self {
+        let redirectHandler = AnyRedirectHandler { (task, response, request, handler) in
+            let payload = KF.RedirectPayload(
+                task: task, response: response, newRequest: request, completionHandler: handler
+            )
+            block(payload)
+        }
+        options.redirectHandler = redirectHandler
+        return self
+    }
+}
+
+// MARK: - Processor
+extension KFOptionSetter {
+
+    /// Sets an image processor for the image task. It replaces the current image processor settings.
+    ///
+    /// - Parameter processor: The processor you want to use to process the image after it is downloaded.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// - Note:
+    /// To append a processor to current ones instead of replacing them all, use `appendProcessor(_:)`.
+    public func setProcessor(_ processor: ImageProcessor) -> Self {
+        options.processor = processor
+        return self
+    }
+
+    /// Sets an array of image processors for the image task. It replaces the current image processor settings.
+    /// - Parameter processors: An array of processors. The processors inside this array will be concatenated one by one
+    ///                         to form a processor pipeline.
+    /// - Returns: A `Self` value with changes applied.
+    ///
+    /// - Note: To append processors to current ones instead of replacing them all, concatenate them by `|>`, then use
+    /// `appendProcessor(_:)`.
+    public func setProcessors(_ processors: [ImageProcessor]) -> Self {
+        switch processors.count {
+        case 0:
+            options.processor = DefaultImageProcessor.default
+        case 1...:
+            options.processor = processors.dropFirst().reduce(processors[0]) { $0 |> $1 }
+        default:
+            assertionFailure("Never happen")
+        }
+        return self
+    }
+
+    /// Appends a processor to the current set processors.
+    /// - Parameter processor: The processor which will be appended to current processor settings.
+    /// - Returns: A `Self` value with changes applied.
+    public func appendProcessor(_ processor: ImageProcessor) -> Self {
+        options.processor = options.processor |> processor
+        return self
+    }
+
+    /// Appends a `RoundCornerImageProcessor` to current processors.
+    /// - Parameters:
+    ///   - radius: The radius will be applied in processing. Specify a certain point value with `.point`, or a fraction
+    ///             of the target image with `.widthFraction`. or `.heightFraction`. For example, given a square image
+    ///             with width and height equals,  `.widthFraction(0.5)` means use half of the length of size and makes
+    ///             the final image a round one.
+    ///   - targetSize: Target size of output image should be. If `nil`, the image will keep its original size after processing.
+    ///   - corners: The target corners which will be applied rounding.
+    ///   - backgroundColor: Background color of the output image. If `nil`, it will use a transparent background.
+    /// - Returns: A `Self` value with changes applied.
+    public func roundCorner(
+        radius: Radius,
+        targetSize: CGSize? = nil,
+        roundingCorners corners: RectCorner = .all,
+        backgroundColor: KFCrossPlatformColor? = nil
+    ) -> Self
+    {
+        let processor = RoundCornerImageProcessor(
+            radius: radius,
+            targetSize: targetSize,
+            roundingCorners: corners,
+            backgroundColor: backgroundColor
+        )
+        return appendProcessor(processor)
+    }
+
+    /// Appends a `BlurImageProcessor` to current processors.
+    /// - Parameter radius: Blur radius for the simulated Gaussian blur.
+    /// - Returns: A `Self` value with changes applied.
+    public func blur(radius: CGFloat) -> Self {
+        appendProcessor(
+            BlurImageProcessor(blurRadius: radius)
+        )
+    }
+
+    /// Appends a `OverlayImageProcessor` to current processors.
+    /// - Parameters:
+    ///   - color: Overlay color will be used to overlay the input image.
+    ///   - fraction: Fraction will be used when overlay the color to image.
+    /// - Returns: A `Self` value with changes applied.
+    public func overlay(color: KFCrossPlatformColor, fraction: CGFloat = 0.5) -> Self {
+        appendProcessor(
+            OverlayImageProcessor(overlay: color, fraction: fraction)
+        )
+    }
+
+    /// Appends a `TintImageProcessor` to current processors.
+    /// - Parameter color: Tint color will be used to tint the input image.
+    /// - Returns: A `Self` value with changes applied.
+    public func tint(color: KFCrossPlatformColor) -> Self {
+        appendProcessor(
+            TintImageProcessor(tint: color)
+        )
+    }
+
+    /// Appends a `BlackWhiteProcessor` to current processors.
+    /// - Returns: A `Self` value with changes applied.
+    public func blackWhite() -> Self {
+        appendProcessor(
+            BlackWhiteProcessor()
+        )
+    }
+
+    /// Appends a `CroppingImageProcessor` to current processors.
+    /// - Parameters:
+    ///   - size: Target size of output image should be.
+    ///   - anchor: Anchor point from which the output size should be calculate. The anchor point is consisted by two
+    ///             values between 0.0 and 1.0. It indicates a related point in current image.
+    ///             See `CroppingImageProcessor.init(size:anchor:)` for more.
+    /// - Returns: A `Self` value with changes applied.
+    public func cropping(size: CGSize, anchor: CGPoint = .init(x: 0.5, y: 0.5)) -> Self {
+        appendProcessor(
+            CroppingImageProcessor(size: size, anchor: anchor)
+        )
+    }
+
+    /// Appends a `DownsamplingImageProcessor` to current processors.
+    ///
+    /// Compared to `ResizingImageProcessor`, the `DownsamplingImageProcessor` does not render the original images and
+    /// then resize it. Instead, it downsamples the input data directly to a thumbnail image. So it is a more efficient
+    /// than `ResizingImageProcessor`. Prefer to use `DownsamplingImageProcessor` as possible
+    /// as you can than the `ResizingImageProcessor`.
+    ///
+    /// Only CG-based images are supported. Animated images (like GIF) is not supported.
+    ///
+    /// - Parameter size: Target size of output image should be. It should be smaller than the size of input image.
+    ///                   If it is larger, the result image will be the same size of input data without downsampling.
+    /// - Returns: A `Self` value with changes applied.
+    public func downsampling(size: CGSize) -> Self {
+        let processor = DownsamplingImageProcessor(size: size)
+        if options.processor == DefaultImageProcessor.default {
+            return setProcessor(processor)
+        } else {
+            return appendProcessor(processor)
+        }
+    }
+
+
+    /// Appends a `ResizingImageProcessor` to current processors.
+    ///
+    /// If you need to resize a data represented image to a smaller size, use `DownsamplingImageProcessor`
+    /// instead, which is more efficient and uses less memory.
+    ///
+    /// - Parameters:
+    ///   - referenceSize: The reference size for resizing operation in point.
+    ///   - mode: Target content mode of output image should be. Default is `.none`.
+    /// - Returns: A `Self` value with changes applied.
+    public func resizing(referenceSize: CGSize, mode: ContentMode = .none) -> Self {
+        appendProcessor(
+            ResizingImageProcessor(referenceSize: referenceSize, mode: mode)
+        )
+    }
+}
+
+// MARK: - Cache Serializer
+extension KFOptionSetter {
+
+    /// Uses a given `CacheSerializer` to convert some data to an image object for retrieving from disk cache or vice
+    /// versa for storing to disk cache.
+    /// - Parameter cacheSerializer: The `CacheSerializer` which will be used.
+    /// - Returns: A `Self` value with changes applied.
+    public func serialize(by cacheSerializer: CacheSerializer) -> Self {
+        options.cacheSerializer = cacheSerializer
+        return self
+    }
+
+    /// Uses a given format to serializer the image data to disk. It converts the image object to the give data format.
+    /// - Parameters:
+    ///   - format: The desired data encoding format when store the image on disk.
+    ///   - jpegCompressionQuality: If the format is `.JPEG`, it specify the compression quality when converting the
+    ///                             image to a JPEG data. Otherwise, it is ignored.
+    /// - Returns: A `Self` value with changes applied.
+    public func serialize(as format: ImageFormat, jpegCompressionQuality: CGFloat? = nil) -> Self {
+        let cacheSerializer: FormatIndicatedCacheSerializer
+        switch format {
+        case .JPEG:
+            cacheSerializer = .jpeg(compressionQuality: jpegCompressionQuality ?? 1.0)
+        case .PNG:
+            cacheSerializer = .png
+        case .GIF:
+            cacheSerializer = .gif
+        case .unknown:
+            cacheSerializer = .png
+        }
+        options.cacheSerializer = cacheSerializer
+        return self
+    }
+}
+
+// MARK: - Image Modifier
+extension KFOptionSetter {
+
+    /// Sets an `ImageModifier` to the image task. Use this to modify the fetched image object properties if needed.
+    ///
+    /// If the image was fetched directly from the downloader, the modifier will run directly after the
+    /// `ImageProcessor`. If the image is being fetched from a cache, the modifier will run after the `CacheSerializer`.
+    /// - Parameter modifier: The `ImageModifier` which will be used to modify the image object.
+    /// - Returns: A `Self` value with changes applied.
+    public func imageModifier(_ modifier: ImageModifier?) -> Self {
+        options.imageModifier = modifier
+        return self
+    }
+
+    /// Sets a block to modify the image object. Use this to modify the fetched image object properties if needed.
+    ///
+    /// If the image was fetched directly from the downloader, the modifier block will run directly after the
+    /// `ImageProcessor`. If the image is being fetched from a cache, the modifier will run after the `CacheSerializer`.
+    ///
+    /// - Parameter block: The block which is used to modify the image object.
+    /// - Returns: A `Self` value with changes applied.
+    public func imageModifier(_ block: @escaping (inout KFCrossPlatformImage) throws -> Void) -> Self {
+        let modifier = AnyImageModifier { image -> KFCrossPlatformImage in
+            var image = image
+            try block(&image)
+            return image
+        }
+        options.imageModifier = modifier
+        return self
+    }
+}
+
+
+// MARK: - Cache Expiration
+extension KFOptionSetter {
+
+    /// Sets the expiration setting for memory cache of this image task.
+    ///
+    /// By default, the underlying `MemoryStorage.Backend` uses the
+    /// expiration in its config for all items. If set, the `MemoryStorage.Backend` will use this value to overwrite
+    /// the config setting for this caching item.
+    ///
+    /// - Parameter expiration: The expiration setting used in cache storage.
+    /// - Returns: A `Self` value with changes applied.
+    public func memoryCacheExpiration(_ expiration: StorageExpiration?) -> Self {
+        options.memoryCacheExpiration = expiration
+        return self
+    }
+
+    /// Sets the expiration extending setting for memory cache. The item expiration time will be incremented by this
+    /// value after access.
+    ///
+    /// By default, the underlying `MemoryStorage.Backend` uses the initial cache expiration as extending
+    /// value: .cacheTime.
+    ///
+    /// To disable extending option at all, sets `.none` to it.
+    ///
+    /// - Parameter extending: The expiration extending setting used in cache storage.
+    /// - Returns: A `Self` value with changes applied.
+    public func memoryCacheAccessExtending(_ extending: ExpirationExtending) -> Self {
+        options.memoryCacheAccessExtendingExpiration = extending
+        return self
+    }
+
+    /// Sets the expiration setting for disk cache of this image task.
+    ///
+    /// By default, the underlying `DiskStorage.Backend` uses the expiration in its config for all items. If set,
+    /// the `DiskStorage.Backend` will use this value to overwrite the config setting for this caching item.
+    ///
+    /// - Parameter expiration: The expiration setting used in cache storage.
+    /// - Returns: A `Self` value with changes applied.
+    public func diskCacheExpiration(_ expiration: StorageExpiration?) -> Self {
+        options.diskCacheExpiration = expiration
+        return self
+    }
+
+    /// Sets the expiration extending setting for disk cache. The item expiration time will be incremented by this
+    /// value after access.
+    ///
+    /// By default, the underlying `DiskStorage.Backend` uses the initial cache expiration as extending
+    /// value: .cacheTime.
+    ///
+    /// To disable extending option at all, sets `.none` to it.
+    ///
+    /// - Parameter extending: The expiration extending setting used in cache storage.
+    /// - Returns: A `Self` value with changes applied.
+    public func diskCacheAccessExtending(_ extending: ExpirationExtending) -> Self {
+        options.diskCacheAccessExtendingExpiration = extending
+        return self
+    }
+}

Pods/Kingfisher/Sources/General/Kingfisher.swift

@@ -0,0 +1,106 @@
+//
+//  Kingfisher.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 16/9/14.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+import ImageIO
+
+#if os(macOS)
+import AppKit
+public typealias KFCrossPlatformImage = NSImage
+public typealias KFCrossPlatformView = NSView
+public typealias KFCrossPlatformColor = NSColor
+public typealias KFCrossPlatformImageView = NSImageView
+public typealias KFCrossPlatformButton = NSButton
+#else
+import UIKit
+public typealias KFCrossPlatformImage = UIImage
+public typealias KFCrossPlatformColor = UIColor
+#if !os(watchOS)
+public typealias KFCrossPlatformImageView = UIImageView
+public typealias KFCrossPlatformView = UIView
+public typealias KFCrossPlatformButton = UIButton
+#if canImport(TVUIKit)
+import TVUIKit
+#endif
+#if canImport(CarPlay) && !targetEnvironment(macCatalyst)
+import CarPlay
+#endif
+#else
+import WatchKit
+#endif
+#endif
+
+/// Wrapper for Kingfisher compatible types. This type provides an extension point for
+/// convenience methods in Kingfisher.
+public struct KingfisherWrapper<Base> {
+    public let base: Base
+    public init(_ base: Base) {
+        self.base = base
+    }
+}
+
+/// Represents an object type that is compatible with Kingfisher. You can use `kf` property to get a
+/// value in the namespace of Kingfisher.
+public protocol KingfisherCompatible: AnyObject { }
+
+/// Represents a value type that is compatible with Kingfisher. You can use `kf` property to get a
+/// value in the namespace of Kingfisher.
+public protocol KingfisherCompatibleValue {}
+
+extension KingfisherCompatible {
+    /// Gets a namespace holder for Kingfisher compatible types.
+    public var kf: KingfisherWrapper<Self> {
+        get { return KingfisherWrapper(self) }
+        set { }
+    }
+}
+
+extension KingfisherCompatibleValue {
+    /// Gets a namespace holder for Kingfisher compatible types.
+    public var kf: KingfisherWrapper<Self> {
+        get { return KingfisherWrapper(self) }
+        set { }
+    }
+}
+
+extension KFCrossPlatformImage: KingfisherCompatible { }
+#if !os(watchOS)
+extension KFCrossPlatformImageView: KingfisherCompatible { }
+extension KFCrossPlatformButton: KingfisherCompatible { }
+extension NSTextAttachment: KingfisherCompatible { }
+#else
+extension WKInterfaceImage: KingfisherCompatible { }
+#endif
+
+#if os(tvOS) && canImport(TVUIKit)
+@available(tvOS 12.0, *)
+extension TVMonogramView: KingfisherCompatible { }
+#endif
+
+#if canImport(CarPlay) && !targetEnvironment(macCatalyst)
+@available(iOS 14.0, *)
+extension CPListItem: KingfisherCompatible { }
+#endif

Pods/Kingfisher/Sources/General/KingfisherError.swift

@@ -0,0 +1,474 @@
+//
+//  KingfisherError.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2018/09/26.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+extension Never {}
+
+/// Represents all the errors which can happen in Kingfisher framework.
+/// Kingfisher related methods always throw a `KingfisherError` or invoke the callback with `KingfisherError`
+/// as its error type. To handle errors from Kingfisher, you switch over the error to get a reason catalog,
+/// then switch over the reason to know error detail.
+public enum KingfisherError: Error {
+
+    // MARK: Error Reason Types
+
+    /// Represents the error reason during networking request phase.
+    ///
+    /// - emptyRequest: The request is empty. Code 1001.
+    /// - invalidURL: The URL of request is invalid. Code 1002.
+    /// - taskCancelled: The downloading task is cancelled by user. Code 1003.
+    public enum RequestErrorReason {
+        
+        /// The request is empty. Code 1001.
+        case emptyRequest
+        
+        /// The URL of request is invalid. Code 1002.
+        /// - request: The request is tend to be sent but its URL is invalid.
+        case invalidURL(request: URLRequest)
+        
+        /// The downloading task is cancelled by user. Code 1003.
+        /// - task: The session data task which is cancelled.
+        /// - token: The cancel token which is used for cancelling the task.
+        case taskCancelled(task: SessionDataTask, token: SessionDataTask.CancelToken)
+    }
+    
+    /// Represents the error reason during networking response phase.
+    ///
+    /// - invalidURLResponse: The response is not a valid URL response. Code 2001.
+    /// - invalidHTTPStatusCode: The response contains an invalid HTTP status code. Code 2002.
+    /// - URLSessionError: An error happens in the system URL session. Code 2003.
+    /// - dataModifyingFailed: Data modifying fails on returning a valid data. Code 2004.
+    /// - noURLResponse: The task is done but no URL response found. Code 2005.
+    public enum ResponseErrorReason {
+        
+        /// The response is not a valid URL response. Code 2001.
+        /// - response: The received invalid URL response.
+        ///             The response is expected to be an HTTP response, but it is not.
+        case invalidURLResponse(response: URLResponse)
+        
+        /// The response contains an invalid HTTP status code. Code 2002.
+        /// - Note:
+        ///   By default, status code 200..<400 is recognized as valid. You can override
+        ///   this behavior by conforming to the `ImageDownloaderDelegate`.
+        /// - response: The received response.
+        case invalidHTTPStatusCode(response: HTTPURLResponse)
+        
+        /// An error happens in the system URL session. Code 2003.
+        /// - error: The underlying URLSession error object.
+        case URLSessionError(error: Error)
+        
+        /// Data modifying fails on returning a valid data. Code 2004.
+        /// - task: The failed task.
+        case dataModifyingFailed(task: SessionDataTask)
+        
+        /// The task is done but no URL response found. Code 2005.
+        /// - task: The failed task.
+        case noURLResponse(task: SessionDataTask)
+
+        /// The task is cancelled by `ImageDownloaderDelegate` due to the `.cancel` response disposition is
+        /// specified by the delegate method. Code 2006.
+        case cancelledByDelegate(response: URLResponse)
+    }
+    
+    /// Represents the error reason during Kingfisher caching system.
+    ///
+    /// - fileEnumeratorCreationFailed: Cannot create a file enumerator for a certain disk URL. Code 3001.
+    /// - invalidFileEnumeratorContent: Cannot get correct file contents from a file enumerator. Code 3002.
+    /// - invalidURLResource: The file at target URL exists, but its URL resource is unavailable. Code 3003.
+    /// - cannotLoadDataFromDisk: The file at target URL exists, but the data cannot be loaded from it. Code 3004.
+    /// - cannotCreateDirectory: Cannot create a folder at a given path. Code 3005.
+    /// - imageNotExisting: The requested image does not exist in cache. Code 3006.
+    /// - cannotConvertToData: Cannot convert an object to data for storing. Code 3007.
+    /// - cannotSerializeImage: Cannot serialize an image to data for storing. Code 3008.
+    /// - cannotCreateCacheFile: Cannot create the cache file at a certain fileURL under a key. Code 3009.
+    /// - cannotSetCacheFileAttribute: Cannot set file attributes to a cached file. Code 3010.
+    public enum CacheErrorReason {
+        
+        /// Cannot create a file enumerator for a certain disk URL. Code 3001.
+        /// - url: The target disk URL from which the file enumerator should be created.
+        case fileEnumeratorCreationFailed(url: URL)
+        
+        /// Cannot get correct file contents from a file enumerator. Code 3002.
+        /// - url: The target disk URL from which the content of a file enumerator should be got.
+        case invalidFileEnumeratorContent(url: URL)
+        
+        /// The file at target URL exists, but its URL resource is unavailable. Code 3003.
+        /// - error: The underlying error thrown by file manager.
+        /// - key: The key used to getting the resource from cache.
+        /// - url: The disk URL where the target cached file exists.
+        case invalidURLResource(error: Error, key: String, url: URL)
+        
+        /// The file at target URL exists, but the data cannot be loaded from it. Code 3004.
+        /// - url: The disk URL where the target cached file exists.
+        /// - error: The underlying error which describes why this error happens.
+        case cannotLoadDataFromDisk(url: URL, error: Error)
+        
+        /// Cannot create a folder at a given path. Code 3005.
+        /// - path: The disk path where the directory creating operation fails.
+        /// - error: The underlying error which describes why this error happens.
+        case cannotCreateDirectory(path: String, error: Error)
+        
+        /// The requested image does not exist in cache. Code 3006.
+        /// - key: Key of the requested image in cache.
+        case imageNotExisting(key: String)
+        
+        /// Cannot convert an object to data for storing. Code 3007.
+        /// - object: The object which needs be convert to data.
+        case cannotConvertToData(object: Any, error: Error)
+        
+        /// Cannot serialize an image to data for storing. Code 3008.
+        /// - image: The input image needs to be serialized to cache.
+        /// - original: The original image data, if exists.
+        /// - serializer: The `CacheSerializer` used for the image serializing.
+        case cannotSerializeImage(image: KFCrossPlatformImage?, original: Data?, serializer: CacheSerializer)
+
+        /// Cannot create the cache file at a certain fileURL under a key. Code 3009.
+        /// - fileURL: The url where the cache file should be created.
+        /// - key: The cache key used for the cache. When caching a file through `KingfisherManager` and Kingfisher's
+        ///        extension method, it is the resolved cache key based on your input `Source` and the image processors.
+        /// - data: The data to be cached.
+        /// - error: The underlying error originally thrown by Foundation when writing the `data` to the disk file at
+        ///          `fileURL`.
+        case cannotCreateCacheFile(fileURL: URL, key: String, data: Data, error: Error)
+
+        /// Cannot set file attributes to a cached file. Code 3010.
+        /// - filePath: The path of target cache file.
+        /// - attributes: The file attribute to be set to the target file.
+        /// - error: The underlying error originally thrown by Foundation when setting the `attributes` to the disk
+        ///          file at `filePath`.
+        case cannotSetCacheFileAttribute(filePath: String, attributes: [FileAttributeKey : Any], error: Error)
+
+        /// The disk storage of cache is not ready. Code 3011.
+        ///
+        /// This is usually due to extremely lack of space on disk storage, and
+        /// Kingfisher failed even when creating the cache folder. The disk storage will be in unusable state. Normally,
+        /// ask user to free some spaces and restart the app to make the disk storage work again.
+        /// - cacheURL: The intended URL which should be the storage folder.
+        case diskStorageIsNotReady(cacheURL: URL)
+    }
+    
+    
+    /// Represents the error reason during image processing phase.
+    ///
+    /// - processingFailed: Image processing fails. There is no valid output image from the processor. Code 4001.
+    public enum ProcessorErrorReason {
+        /// Image processing fails. There is no valid output image from the processor. Code 4001.
+        /// - processor: The `ImageProcessor` used to process the image or its data in `item`.
+        /// - item: The image or its data content.
+        case processingFailed(processor: ImageProcessor, item: ImageProcessItem)
+    }
+
+    /// Represents the error reason during image setting in a view related class.
+    ///
+    /// - emptySource: The input resource is empty or `nil`. Code 5001.
+    /// - notCurrentSourceTask: The source task is finished, but it is not the one expected now. Code 5002.
+    /// - dataProviderError: An error happens during getting data from an `ImageDataProvider`. Code 5003.
+    public enum ImageSettingErrorReason {
+        
+        /// The input resource is empty or `nil`. Code 5001.
+        case emptySource
+        
+        /// The resource task is finished, but it is not the one expected now. This usually happens when you set another
+        /// resource on the view without cancelling the current on-going one. The previous setting task will fail with
+        /// this `.notCurrentSourceTask` error when a result got, regardless of it being successful or not for that task.
+        /// The result of this original task is contained in the associated value.
+        /// Code 5002.
+        /// - result: The `RetrieveImageResult` if the source task is finished without problem. `nil` if an error
+        ///           happens.
+        /// - error: The `Error` if an issue happens during image setting task. `nil` if the task finishes without
+        ///          problem.
+        /// - source: The original source value of the task.
+        case notCurrentSourceTask(result: RetrieveImageResult?, error: Error?, source: Source)
+
+        /// An error happens during getting data from an `ImageDataProvider`. Code 5003.
+        case dataProviderError(provider: ImageDataProvider, error: Error)
+
+        /// No more alternative `Source` can be used in current loading process. It means that the
+        /// `.alternativeSources` are used and Kingfisher tried to recovery from the original error, but still
+        /// fails for all the given alternative sources. The associated value holds all the errors encountered during
+        /// the load process, including the original source loading error and all the alternative sources errors.
+        /// Code 5004.
+        case alternativeSourcesExhausted([PropagationError])
+    }
+
+    // MARK: Member Cases
+    
+    /// Represents the error reason during networking request phase.
+    case requestError(reason: RequestErrorReason)
+    /// Represents the error reason during networking response phase.
+    case responseError(reason: ResponseErrorReason)
+    /// Represents the error reason during Kingfisher caching system.
+    case cacheError(reason: CacheErrorReason)
+    /// Represents the error reason during image processing phase.
+    case processorError(reason: ProcessorErrorReason)
+    /// Represents the error reason during image setting in a view related class.
+    case imageSettingError(reason: ImageSettingErrorReason)
+
+    // MARK: Helper Properties & Methods
+
+    /// Helper property to check whether this error is a `RequestErrorReason.taskCancelled` or not.
+    public var isTaskCancelled: Bool {
+        if case .requestError(reason: .taskCancelled) = self {
+            return true
+        }
+        return false
+    }
+
+    /// Helper method to check whether this error is a `ResponseErrorReason.invalidHTTPStatusCode` and the
+    /// associated value is a given status code.
+    ///
+    /// - Parameter code: The given status code.
+    /// - Returns: If `self` is a `ResponseErrorReason.invalidHTTPStatusCode` error
+    ///            and its status code equals to `code`, `true` is returned. Otherwise, `false`.
+    public func isInvalidResponseStatusCode(_ code: Int) -> Bool {
+        if case .responseError(reason: .invalidHTTPStatusCode(let response)) = self {
+            return response.statusCode == code
+        }
+        return false
+    }
+
+    public var isInvalidResponseStatusCode: Bool {
+        if case .responseError(reason: .invalidHTTPStatusCode) = self {
+            return true
+        }
+        return false
+    }
+
+    /// Helper property to check whether this error is a `ImageSettingErrorReason.notCurrentSourceTask` or not.
+    /// When a new image setting task starts while the old one is still running, the new task identifier will be
+    /// set and the old one is overwritten. A `.notCurrentSourceTask` error will be raised when the old task finishes
+    /// to let you know the setting process finishes with a certain result, but the image view or button is not set.
+    public var isNotCurrentTask: Bool {
+        if case .imageSettingError(reason: .notCurrentSourceTask(_, _, _)) = self {
+            return true
+        }
+        return false
+    }
+
+    var isLowDataModeConstrained: Bool {
+        if #available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *),
+           case .responseError(reason: .URLSessionError(let sessionError)) = self,
+           let urlError = sessionError as? URLError,
+           urlError.networkUnavailableReason == .constrained
+        {
+            return true
+        }
+        return false
+    }
+
+}
+
+// MARK: - LocalizedError Conforming
+extension KingfisherError: LocalizedError {
+    
+    /// A localized message describing what error occurred.
+    public var errorDescription: String? {
+        switch self {
+        case .requestError(let reason): return reason.errorDescription
+        case .responseError(let reason): return reason.errorDescription
+        case .cacheError(let reason): return reason.errorDescription
+        case .processorError(let reason): return reason.errorDescription
+        case .imageSettingError(let reason): return reason.errorDescription
+        }
+    }
+}
+
+
+// MARK: - CustomNSError Conforming
+extension KingfisherError: CustomNSError {
+
+    /// The error domain of `KingfisherError`. All errors from Kingfisher is under this domain.
+    public static let domain = "com.onevcat.Kingfisher.Error"
+
+    /// The error code within the given domain.
+    public var errorCode: Int {
+        switch self {
+        case .requestError(let reason): return reason.errorCode
+        case .responseError(let reason): return reason.errorCode
+        case .cacheError(let reason): return reason.errorCode
+        case .processorError(let reason): return reason.errorCode
+        case .imageSettingError(let reason): return reason.errorCode
+        }
+    }
+}
+
+extension KingfisherError.RequestErrorReason {
+    var errorDescription: String? {
+        switch self {
+        case .emptyRequest:
+            return "The request is empty or `nil`."
+        case .invalidURL(let request):
+            return "The request contains an invalid or empty URL. Request: \(request)."
+        case .taskCancelled(let task, let token):
+            return "The session task was cancelled. Task: \(task), cancel token: \(token)."
+        }
+    }
+    
+    var errorCode: Int {
+        switch self {
+        case .emptyRequest: return 1001
+        case .invalidURL: return 1002
+        case .taskCancelled: return 1003
+        }
+    }
+}
+
+extension KingfisherError.ResponseErrorReason {
+    var errorDescription: String? {
+        switch self {
+        case .invalidURLResponse(let response):
+            return "The URL response is invalid: \(response)"
+        case .invalidHTTPStatusCode(let response):
+            return "The HTTP status code in response is invalid. Code: \(response.statusCode), response: \(response)."
+        case .URLSessionError(let error):
+            return "A URL session error happened. The underlying error: \(error)"
+        case .dataModifyingFailed(let task):
+            return "The data modifying delegate returned `nil` for the downloaded data. Task: \(task)."
+        case .noURLResponse(let task):
+            return "No URL response received. Task: \(task)."
+        case .cancelledByDelegate(let response):
+            return "The downloading task is cancelled by the downloader delegate. Response: \(response)."
+
+        }
+    }
+    
+    var errorCode: Int {
+        switch self {
+        case .invalidURLResponse: return 2001
+        case .invalidHTTPStatusCode: return 2002
+        case .URLSessionError: return 2003
+        case .dataModifyingFailed: return 2004
+        case .noURLResponse: return 2005
+        case .cancelledByDelegate: return 2006
+        }
+    }
+}
+
+extension KingfisherError.CacheErrorReason {
+    var errorDescription: String? {
+        switch self {
+        case .fileEnumeratorCreationFailed(let url):
+            return "Cannot create file enumerator for URL: \(url)."
+        case .invalidFileEnumeratorContent(let url):
+            return "Cannot get contents from the file enumerator at URL: \(url)."
+        case .invalidURLResource(let error, let key, let url):
+            return "Cannot get URL resource values or data for the given URL: \(url). " +
+                   "Cache key: \(key). Underlying error: \(error)"
+        case .cannotLoadDataFromDisk(let url, let error):
+            return "Cannot load data from disk at URL: \(url). Underlying error: \(error)"
+        case .cannotCreateDirectory(let path, let error):
+            return "Cannot create directory at given path: Path: \(path). Underlying error: \(error)"
+        case .imageNotExisting(let key):
+            return "The image is not in cache, but you requires it should only be " +
+                   "from cache by enabling the `.onlyFromCache` option. Key: \(key)."
+        case .cannotConvertToData(let object, let error):
+            return "Cannot convert the input object to a `Data` object when storing it to disk cache. " +
+                   "Object: \(object). Underlying error: \(error)"
+        case .cannotSerializeImage(let image, let originalData, let serializer):
+            return "Cannot serialize an image due to the cache serializer returning `nil`. " +
+                   "Image: \(String(describing:image)), original data: \(String(describing: originalData)), " +
+                   "serializer: \(serializer)."
+        case .cannotCreateCacheFile(let fileURL, let key, let data, let error):
+            return "Cannot create cache file at url: \(fileURL), key: \(key), data length: \(data.count). " +
+                   "Underlying foundation error: \(error)."
+        case .cannotSetCacheFileAttribute(let filePath, let attributes, let error):
+            return "Cannot set file attribute for the cache file at path: \(filePath), attributes: \(attributes)." +
+                   "Underlying foundation error: \(error)."
+        case .diskStorageIsNotReady(let cacheURL):
+            return "The disk storage is not ready to use yet at URL: '\(cacheURL)'. " +
+                "This is usually caused by extremely lack of disk space. Ask users to free up some space and restart the app."
+        }
+    }
+    
+    var errorCode: Int {
+        switch self {
+        case .fileEnumeratorCreationFailed: return 3001
+        case .invalidFileEnumeratorContent: return 3002
+        case .invalidURLResource: return 3003
+        case .cannotLoadDataFromDisk: return 3004
+        case .cannotCreateDirectory: return 3005
+        case .imageNotExisting: return 3006
+        case .cannotConvertToData: return 3007
+        case .cannotSerializeImage: return 3008
+        case .cannotCreateCacheFile: return 3009
+        case .cannotSetCacheFileAttribute: return 3010
+        case .diskStorageIsNotReady: return 3011
+        }
+    }
+}
+
+extension KingfisherError.ProcessorErrorReason {
+    var errorDescription: String? {
+        switch self {
+        case .processingFailed(let processor, let item):
+            return "Processing image failed. Processor: \(processor). Processing item: \(item)."
+        }
+    }
+    
+    var errorCode: Int {
+        switch self {
+        case .processingFailed: return 4001
+        }
+    }
+}
+
+extension KingfisherError.ImageSettingErrorReason {
+    var errorDescription: String? {
+        switch self {
+        case .emptySource:
+            return "The input resource is empty."
+        case .notCurrentSourceTask(let result, let error, let resource):
+            if let result = result {
+                return "Retrieving resource succeeded, but this source is " +
+                       "not the one currently expected. Result: \(result). Resource: \(resource)."
+            } else if let error = error {
+                return "Retrieving resource failed, and this resource is " +
+                       "not the one currently expected. Error: \(error). Resource: \(resource)."
+            } else {
+                return nil
+            }
+        case .dataProviderError(let provider, let error):
+            return "Image data provider fails to provide data. Provider: \(provider), error: \(error)"
+        case .alternativeSourcesExhausted(let errors):
+            return "Image setting from alternaive sources failed: \(errors)"
+        }
+    }
+    
+    var errorCode: Int {
+        switch self {
+        case .emptySource: return 5001
+        case .notCurrentSourceTask: return 5002
+        case .dataProviderError: return 5003
+        case .alternativeSourcesExhausted: return 5004
+        }
+    }
+}

Pods/Kingfisher/Sources/General/KingfisherManager.swift

@@ -0,0 +1,807 @@
+//
+//  KingfisherManager.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 15/4/6.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+
+import Foundation
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+/// The downloading progress block type.
+/// The parameter value is the `receivedSize` of current response.
+/// The second parameter is the total expected data length from response's "Content-Length" header.
+/// If the expected length is not available, this block will not be called.
+public typealias DownloadProgressBlock = ((_ receivedSize: Int64, _ totalSize: Int64) -> Void)
+
+/// Represents the result of a Kingfisher retrieving image task.
+public struct RetrieveImageResult {
+    /// Gets the image object of this result.
+    public let image: KFCrossPlatformImage
+
+    /// Gets the cache source of the image. It indicates from which layer of cache this image is retrieved.
+    /// If the image is just downloaded from network, `.none` will be returned.
+    public let cacheType: CacheType
+
+    /// The `Source` which this result is related to. This indicated where the `image` of `self` is referring.
+    public let source: Source
+
+    /// The original `Source` from which the retrieve task begins. It can be different from the `source` property.
+    /// When an alternative source loading happened, the `source` will be the replacing loading target, while the
+    /// `originalSource` will be kept as the initial `source` which issued the image loading process.
+    public let originalSource: Source
+    
+    /// Gets the data behind the result.
+    ///
+    /// If this result is from a network downloading (when `cacheType == .none`), calling this returns the downloaded
+    /// data. If the reuslt is from cache, it serializes the image with the given cache serializer in the loading option
+    /// and returns the result.
+    ///
+    /// - Note:
+    /// This can be a time-consuming action, so if you need to use the data for multiple times, it is suggested to hold
+    /// it and prevent keeping calling this too frequently.
+    public let data: () -> Data?
+}
+
+/// A struct that stores some related information of an `KingfisherError`. It provides some context information for
+/// a pure error so you can identify the error easier.
+public struct PropagationError {
+
+    /// The `Source` to which current `error` is bound.
+    public let source: Source
+
+    /// The actual error happens in framework.
+    public let error: KingfisherError
+}
+
+
+/// The downloading task updated block type. The parameter `newTask` is the updated new task of image setting process.
+/// It is a `nil` if the image loading does not require an image downloading process. If an image downloading is issued,
+/// this value will contain the actual `DownloadTask` for you to keep and cancel it later if you need.
+public typealias DownloadTaskUpdatedBlock = ((_ newTask: DownloadTask?) -> Void)
+
+/// Main manager class of Kingfisher. It connects Kingfisher downloader and cache,
+/// to provide a set of convenience methods to use Kingfisher for tasks.
+/// You can use this class to retrieve an image via a specified URL from web or cache.
+public class KingfisherManager {
+
+    /// Represents a shared manager used across Kingfisher.
+    /// Use this instance for getting or storing images with Kingfisher.
+    public static let shared = KingfisherManager()
+
+    // Mark: Public Properties
+    /// The `ImageCache` used by this manager. It is `ImageCache.default` by default.
+    /// If a cache is specified in `KingfisherManager.defaultOptions`, the value in `defaultOptions` will be
+    /// used instead.
+    public var cache: ImageCache
+    
+    /// The `ImageDownloader` used by this manager. It is `ImageDownloader.default` by default.
+    /// If a downloader is specified in `KingfisherManager.defaultOptions`, the value in `defaultOptions` will be
+    /// used instead.
+    public var downloader: ImageDownloader
+    
+    /// Default options used by the manager. This option will be used in
+    /// Kingfisher manager related methods, as well as all view extension methods.
+    /// You can also passing other options for each image task by sending an `options` parameter
+    /// to Kingfisher's APIs. The per image options will overwrite the default ones,
+    /// if the option exists in both.
+    public var defaultOptions = KingfisherOptionsInfo.empty
+    
+    // Use `defaultOptions` to overwrite the `downloader` and `cache`.
+    private var currentDefaultOptions: KingfisherOptionsInfo {
+        return [.downloader(downloader), .targetCache(cache)] + defaultOptions
+    }
+
+    private let processingQueue: CallbackQueue
+    
+    private convenience init() {
+        self.init(downloader: .default, cache: .default)
+    }
+
+    /// Creates an image setting manager with specified downloader and cache.
+    ///
+    /// - Parameters:
+    ///   - downloader: The image downloader used to download images.
+    ///   - cache: The image cache which stores memory and disk images.
+    public init(downloader: ImageDownloader, cache: ImageCache) {
+        self.downloader = downloader
+        self.cache = cache
+
+        let processQueueName = "com.onevcat.Kingfisher.KingfisherManager.processQueue.\(UUID().uuidString)"
+        processingQueue = .dispatch(DispatchQueue(label: processQueueName))
+    }
+
+    // MARK: - Getting Images
+
+    /// Gets an image from a given resource.
+    /// - Parameters:
+    ///   - resource: The `Resource` object defines data information like key or URL.
+    ///   - options: Options to use when creating the image.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called. `progressBlock` is always called in
+    ///                    main queue.
+    ///   - downloadTaskUpdated: Called when a new image downloading task is created for current image retrieving. This
+    ///                          usually happens when an alternative source is used to replace the original (failed)
+    ///                          task. You can update your reference of `DownloadTask` if you want to manually `cancel`
+    ///                          the new task.
+    ///   - completionHandler: Called when the image retrieved and set finished. This completion handler will be invoked
+    ///                        from the `options.callbackQueue`. If not specified, the main queue will be used.
+    /// - Returns: A task represents the image downloading. If there is a download task starts for `.network` resource,
+    ///            the started `DownloadTask` is returned. Otherwise, `nil` is returned.
+    ///
+    /// - Note:
+    ///    This method will first check whether the requested `resource` is already in cache or not. If cached,
+    ///    it returns `nil` and invoke the `completionHandler` after the cached image retrieved. Otherwise, it
+    ///    will download the `resource`, store it in cache, then call `completionHandler`.
+    @discardableResult
+    public func retrieveImage(
+        with resource: Resource,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        downloadTaskUpdated: DownloadTaskUpdatedBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)?) -> DownloadTask?
+    {
+        return retrieveImage(
+            with: resource.convertToSource(),
+            options: options,
+            progressBlock: progressBlock,
+            downloadTaskUpdated: downloadTaskUpdated,
+            completionHandler: completionHandler
+        )
+    }
+
+    /// Gets an image from a given resource.
+    ///
+    /// - Parameters:
+    ///   - source: The `Source` object defines data information from network or a data provider.
+    ///   - options: Options to use when creating the image.
+    ///   - progressBlock: Called when the image downloading progress gets updated. If the response does not contain an
+    ///                    `expectedContentLength`, this block will not be called. `progressBlock` is always called in
+    ///                    main queue.
+    ///   - downloadTaskUpdated: Called when a new image downloading task is created for current image retrieving. This
+    ///                          usually happens when an alternative source is used to replace the original (failed)
+    ///                          task. You can update your reference of `DownloadTask` if you want to manually `cancel`
+    ///                          the new task.
+    ///   - completionHandler: Called when the image retrieved and set finished. This completion handler will be invoked
+    ///                        from the `options.callbackQueue`. If not specified, the main queue will be used.
+    /// - Returns: A task represents the image downloading. If there is a download task starts for `.network` resource,
+    ///            the started `DownloadTask` is returned. Otherwise, `nil` is returned.
+    ///
+    /// - Note:
+    ///    This method will first check whether the requested `source` is already in cache or not. If cached,
+    ///    it returns `nil` and invoke the `completionHandler` after the cached image retrieved. Otherwise, it
+    ///    will try to load the `source`, store it in cache, then call `completionHandler`.
+    ///
+    @discardableResult
+    public func retrieveImage(
+        with source: Source,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        downloadTaskUpdated: DownloadTaskUpdatedBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)?) -> DownloadTask?
+    {
+        let options = currentDefaultOptions + (options ?? .empty)
+        let info = KingfisherParsedOptionsInfo(options)
+        return retrieveImage(
+            with: source,
+            options: info,
+            progressBlock: progressBlock,
+            downloadTaskUpdated: downloadTaskUpdated,
+            completionHandler: completionHandler)
+    }
+
+    func retrieveImage(
+        with source: Source,
+        options: KingfisherParsedOptionsInfo,
+        progressBlock: DownloadProgressBlock? = nil,
+        downloadTaskUpdated: DownloadTaskUpdatedBlock? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)?) -> DownloadTask?
+    {
+        var info = options
+        if let block = progressBlock {
+            info.onDataReceived = (info.onDataReceived ?? []) + [ImageLoadingProgressSideEffect(block)]
+        }
+        return retrieveImage(
+            with: source,
+            options: info,
+            downloadTaskUpdated: downloadTaskUpdated,
+            progressiveImageSetter: nil,
+            completionHandler: completionHandler)
+    }
+
+    func retrieveImage(
+        with source: Source,
+        options: KingfisherParsedOptionsInfo,
+        downloadTaskUpdated: DownloadTaskUpdatedBlock? = nil,
+        progressiveImageSetter: ((KFCrossPlatformImage?) -> Void)? = nil,
+        referenceTaskIdentifierChecker: (() -> Bool)? = nil,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)?) -> DownloadTask?
+    {
+        var options = options
+        if let provider = ImageProgressiveProvider(options, refresh: { image in
+            guard let setter = progressiveImageSetter else {
+                return
+            }
+            guard let strategy = options.progressiveJPEG?.onImageUpdated(image) else {
+                setter(image)
+                return
+            }
+            switch strategy {
+            case .default: setter(image)
+            case .keepCurrent: break
+            case .replace(let newImage): setter(newImage)
+            }
+        }) {
+            options.onDataReceived = (options.onDataReceived ?? []) + [provider]
+        }
+        if let checker = referenceTaskIdentifierChecker {
+            options.onDataReceived?.forEach {
+                $0.onShouldApply = checker
+            }
+        }
+        
+        let retrievingContext = RetrievingContext(options: options, originalSource: source)
+        var retryContext: RetryContext?
+
+        func startNewRetrieveTask(
+            with source: Source,
+            downloadTaskUpdated: DownloadTaskUpdatedBlock?
+        ) {
+            let newTask = self.retrieveImage(with: source, context: retrievingContext) { result in
+                handler(currentSource: source, result: result)
+            }
+            downloadTaskUpdated?(newTask)
+        }
+
+        func failCurrentSource(_ source: Source, with error: KingfisherError) {
+            // Skip alternative sources if the user cancelled it.
+            guard !error.isTaskCancelled else {
+                completionHandler?(.failure(error))
+                return
+            }
+            // When low data mode constrained error, retry with the low data mode source instead of use alternative on fly.
+            guard !error.isLowDataModeConstrained else {
+                if let source = retrievingContext.options.lowDataModeSource {
+                    retrievingContext.options.lowDataModeSource = nil
+                    startNewRetrieveTask(with: source, downloadTaskUpdated: downloadTaskUpdated)
+                } else {
+                    // This should not happen.
+                    completionHandler?(.failure(error))
+                }
+                return
+            }
+            if let nextSource = retrievingContext.popAlternativeSource() {
+                retrievingContext.appendError(error, to: source)
+                startNewRetrieveTask(with: nextSource, downloadTaskUpdated: downloadTaskUpdated)
+            } else {
+                // No other alternative source. Finish with error.
+                if retrievingContext.propagationErrors.isEmpty {
+                    completionHandler?(.failure(error))
+                } else {
+                    retrievingContext.appendError(error, to: source)
+                    let finalError = KingfisherError.imageSettingError(
+                        reason: .alternativeSourcesExhausted(retrievingContext.propagationErrors)
+                    )
+                    completionHandler?(.failure(finalError))
+                }
+            }
+        }
+
+        func handler(currentSource: Source, result: (Result<RetrieveImageResult, KingfisherError>)) -> Void {
+            switch result {
+            case .success:
+                completionHandler?(result)
+            case .failure(let error):
+                if let retryStrategy = options.retryStrategy {
+                    let context = retryContext?.increaseRetryCount() ?? RetryContext(source: source, error: error)
+                    retryContext = context
+
+                    retryStrategy.retry(context: context) { decision in
+                        switch decision {
+                        case .retry(let userInfo):
+                            retryContext?.userInfo = userInfo
+                            startNewRetrieveTask(with: source, downloadTaskUpdated: downloadTaskUpdated)
+                        case .stop:
+                            failCurrentSource(currentSource, with: error)
+                        }
+                    }
+                } else {
+                    failCurrentSource(currentSource, with: error)
+                }
+            }
+        }
+
+        return retrieveImage(
+            with: source,
+            context: retrievingContext)
+        {
+            result in
+            handler(currentSource: source, result: result)
+        }
+
+    }
+    
+    private func retrieveImage(
+        with source: Source,
+        context: RetrievingContext,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)?) -> DownloadTask?
+    {
+        let options = context.options
+        if options.forceRefresh {
+            return loadAndCacheImage(
+                source: source,
+                context: context,
+                completionHandler: completionHandler)?.value
+            
+        } else {
+            let loadedFromCache = retrieveImageFromCache(
+                source: source,
+                context: context,
+                completionHandler: completionHandler)
+            
+            if loadedFromCache {
+                return nil
+            }
+            
+            if options.onlyFromCache {
+                let error = KingfisherError.cacheError(reason: .imageNotExisting(key: source.cacheKey))
+                completionHandler?(.failure(error))
+                return nil
+            }
+            
+            return loadAndCacheImage(
+                source: source,
+                context: context,
+                completionHandler: completionHandler)?.value
+        }
+    }
+
+    func provideImage(
+        provider: ImageDataProvider,
+        options: KingfisherParsedOptionsInfo,
+        completionHandler: ((Result<ImageLoadingResult, KingfisherError>) -> Void)?)
+    {
+        guard let  completionHandler = completionHandler else { return }
+        provider.data { result in
+            switch result {
+            case .success(let data):
+                (options.processingQueue ?? self.processingQueue).execute {
+                    let processor = options.processor
+                    let processingItem = ImageProcessItem.data(data)
+                    guard let image = processor.process(item: processingItem, options: options) else {
+                        options.callbackQueue.execute {
+                            let error = KingfisherError.processorError(
+                                reason: .processingFailed(processor: processor, item: processingItem))
+                            completionHandler(.failure(error))
+                        }
+                        return
+                    }
+
+                    options.callbackQueue.execute {
+                        let result = ImageLoadingResult(image: image, url: nil, originalData: data)
+                        completionHandler(.success(result))
+                    }
+                }
+            case .failure(let error):
+                options.callbackQueue.execute {
+                    let error = KingfisherError.imageSettingError(
+                        reason: .dataProviderError(provider: provider, error: error))
+                    completionHandler(.failure(error))
+                }
+
+            }
+        }
+    }
+
+    private func cacheImage(
+        source: Source,
+        options: KingfisherParsedOptionsInfo,
+        context: RetrievingContext,
+        result: Result<ImageLoadingResult, KingfisherError>,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)?
+    )
+    {
+        switch result {
+        case .success(let value):
+            let needToCacheOriginalImage = options.cacheOriginalImage &&
+                                           options.processor != DefaultImageProcessor.default
+            let coordinator = CacheCallbackCoordinator(
+                shouldWaitForCache: options.waitForCache, shouldCacheOriginal: needToCacheOriginalImage)
+            let result = RetrieveImageResult(
+                image: options.imageModifier?.modify(value.image) ?? value.image,
+                cacheType: .none,
+                source: source,
+                originalSource: context.originalSource,
+                data: {  value.originalData }
+            )
+            // Add image to cache.
+            let targetCache = options.targetCache ?? self.cache
+            targetCache.store(
+                value.image,
+                original: value.originalData,
+                forKey: source.cacheKey,
+                options: options,
+                toDisk: !options.cacheMemoryOnly)
+            {
+                _ in
+                coordinator.apply(.cachingImage) {
+                    completionHandler?(.success(result))
+                }
+            }
+
+            // Add original image to cache if necessary.
+
+            if needToCacheOriginalImage {
+                let originalCache = options.originalCache ?? targetCache
+                originalCache.storeToDisk(
+                    value.originalData,
+                    forKey: source.cacheKey,
+                    processorIdentifier: DefaultImageProcessor.default.identifier,
+                    expiration: options.diskCacheExpiration)
+                {
+                    _ in
+                    coordinator.apply(.cachingOriginalImage) {
+                        completionHandler?(.success(result))
+                    }
+                }
+            }
+
+            coordinator.apply(.cacheInitiated) {
+                completionHandler?(.success(result))
+            }
+
+        case .failure(let error):
+            completionHandler?(.failure(error))
+        }
+    }
+
+    @discardableResult
+    func loadAndCacheImage(
+        source: Source,
+        context: RetrievingContext,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)?) -> DownloadTask.WrappedTask?
+    {
+        let options = context.options
+        func _cacheImage(_ result: Result<ImageLoadingResult, KingfisherError>) {
+            cacheImage(
+                source: source,
+                options: options,
+                context: context,
+                result: result,
+                completionHandler: completionHandler
+            )
+        }
+
+        switch source {
+        case .network(let resource):
+            let downloader = options.downloader ?? self.downloader
+            let task = downloader.downloadImage(
+                with: resource.downloadURL, options: options, completionHandler: _cacheImage
+            )
+
+
+            // The code below is neat, but it fails the Swift 5.2 compiler with a runtime crash when 
+            // `BUILD_LIBRARY_FOR_DISTRIBUTION` is turned on. I believe it is a bug in the compiler. 
+            // Let's fallback to a traditional style before it can be fixed in Swift.
+            //
+            // https://github.com/onevcat/Kingfisher/issues/1436
+            //
+            // return task.map(DownloadTask.WrappedTask.download)
+
+            if let task = task {
+                return .download(task)
+            } else {
+                return nil
+            }
+
+        case .provider(let provider):
+            provideImage(provider: provider, options: options, completionHandler: _cacheImage)
+            return .dataProviding
+        }
+    }
+    
+    /// Retrieves image from memory or disk cache.
+    ///
+    /// - Parameters:
+    ///   - source: The target source from which to get image.
+    ///   - key: The key to use when caching the image.
+    ///   - url: Image request URL. This is not used when retrieving image from cache. It is just used for
+    ///          `RetrieveImageResult` callback compatibility.
+    ///   - options: Options on how to get the image from image cache.
+    ///   - completionHandler: Called when the image retrieving finishes, either with succeeded
+    ///                        `RetrieveImageResult` or an error.
+    /// - Returns: `true` if the requested image or the original image before being processed is existing in cache.
+    ///            Otherwise, this method returns `false`.
+    ///
+    /// - Note:
+    ///    The image retrieving could happen in either memory cache or disk cache. The `.processor` option in
+    ///    `options` will be considered when searching in the cache. If no processed image is found, Kingfisher
+    ///    will try to check whether an original version of that image is existing or not. If there is already an
+    ///    original, Kingfisher retrieves it from cache and processes it. Then, the processed image will be store
+    ///    back to cache for later use.
+    func retrieveImageFromCache(
+        source: Source,
+        context: RetrievingContext,
+        completionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void)?) -> Bool
+    {
+        let options = context.options
+        // 1. Check whether the image was already in target cache. If so, just get it.
+        let targetCache = options.targetCache ?? cache
+        let key = source.cacheKey
+        let targetImageCached = targetCache.imageCachedType(
+            forKey: key, processorIdentifier: options.processor.identifier)
+        
+        let validCache = targetImageCached.cached &&
+            (options.fromMemoryCacheOrRefresh == false || targetImageCached == .memory)
+        if validCache {
+            targetCache.retrieveImage(forKey: key, options: options) { result in
+                guard let completionHandler = completionHandler else { return }
+                
+                // TODO: Optimize it when we can use async across all the project.
+                func checkResultImageAndCallback(_ inputImage: KFCrossPlatformImage) {
+                    var image = inputImage
+                    if image.kf.imageFrameCount != nil && image.kf.imageFrameCount != 1, let data = image.kf.animatedImageData {
+                        // Always recreate animated image representation since it is possible to be loaded in different options.
+                        // https://github.com/onevcat/Kingfisher/issues/1923
+                        image = options.processor.process(item: .data(data), options: options) ?? .init()
+                    }
+                    if let modifier = options.imageModifier {
+                        image = modifier.modify(image)
+                    }
+                    let value = result.map {
+                        RetrieveImageResult(
+                            image: image,
+                            cacheType: $0.cacheType,
+                            source: source,
+                            originalSource: context.originalSource,
+                            data: { options.cacheSerializer.data(with: image, original: nil) }
+                        )
+                    }
+                    completionHandler(value)
+                }
+                
+                result.match { cacheResult in
+                    options.callbackQueue.execute {
+                        guard let image = cacheResult.image else {
+                            completionHandler(.failure(KingfisherError.cacheError(reason: .imageNotExisting(key: key))))
+                            return
+                        }
+                        
+                        if options.cacheSerializer.originalDataUsed {
+                            let processor = options.processor
+                            (options.processingQueue ?? self.processingQueue).execute {
+                                let item = ImageProcessItem.image(image)
+                                guard let processedImage = processor.process(item: item, options: options) else {
+                                    let error = KingfisherError.processorError(
+                                        reason: .processingFailed(processor: processor, item: item))
+                                    options.callbackQueue.execute { completionHandler(.failure(error)) }
+                                    return
+                                }
+                                options.callbackQueue.execute {
+                                    checkResultImageAndCallback(processedImage)
+                                }
+                            }
+                        } else {
+                            checkResultImageAndCallback(image)
+                        }
+                    }
+                } onFailure: { error in
+                    options.callbackQueue.execute {
+                        completionHandler(.failure(KingfisherError.cacheError(reason: .imageNotExisting(key: key))))
+                    }
+                }
+            }
+            return true
+        }
+
+        // 2. Check whether the original image exists. If so, get it, process it, save to storage and return.
+        let originalCache = options.originalCache ?? targetCache
+        // No need to store the same file in the same cache again.
+        if originalCache === targetCache && options.processor == DefaultImageProcessor.default {
+            return false
+        }
+
+        // Check whether the unprocessed image existing or not.
+        let originalImageCacheType = originalCache.imageCachedType(
+            forKey: key, processorIdentifier: DefaultImageProcessor.default.identifier)
+        let canAcceptDiskCache = !options.fromMemoryCacheOrRefresh
+        
+        let canUseOriginalImageCache =
+            (canAcceptDiskCache && originalImageCacheType.cached) ||
+            (!canAcceptDiskCache && originalImageCacheType == .memory)
+        
+        if canUseOriginalImageCache {
+            // Now we are ready to get found the original image from cache. We need the unprocessed image, so remove
+            // any processor from options first.
+            var optionsWithoutProcessor = options
+            optionsWithoutProcessor.processor = DefaultImageProcessor.default
+            originalCache.retrieveImage(forKey: key, options: optionsWithoutProcessor) { result in
+
+                result.match(
+                    onSuccess: { cacheResult in
+                        guard let image = cacheResult.image else {
+                            assertionFailure("The image (under key: \(key) should be existing in the original cache.")
+                            return
+                        }
+
+                        let processor = options.processor
+                        (options.processingQueue ?? self.processingQueue).execute {
+                            let item = ImageProcessItem.image(image)
+                            guard let processedImage = processor.process(item: item, options: options) else {
+                                let error = KingfisherError.processorError(
+                                    reason: .processingFailed(processor: processor, item: item))
+                                options.callbackQueue.execute { completionHandler?(.failure(error)) }
+                                return
+                            }
+
+                            var cacheOptions = options
+                            cacheOptions.callbackQueue = .untouch
+
+                            let coordinator = CacheCallbackCoordinator(
+                                shouldWaitForCache: options.waitForCache, shouldCacheOriginal: false)
+
+                            let image = options.imageModifier?.modify(processedImage) ?? processedImage
+                            let result = RetrieveImageResult(
+                                image: image,
+                                cacheType: .none,
+                                source: source,
+                                originalSource: context.originalSource,
+                                data: { options.cacheSerializer.data(with: processedImage, original: nil) }
+                            )
+
+                            targetCache.store(
+                                processedImage,
+                                forKey: key,
+                                options: cacheOptions,
+                                toDisk: !options.cacheMemoryOnly)
+                            {
+                                _ in
+                                coordinator.apply(.cachingImage) {
+                                    options.callbackQueue.execute { completionHandler?(.success(result)) }
+                                }
+                            }
+
+                            coordinator.apply(.cacheInitiated) {
+                                options.callbackQueue.execute { completionHandler?(.success(result)) }
+                            }
+                        }
+                    },
+                    onFailure: { _ in
+                        // This should not happen actually, since we already confirmed `originalImageCached` is `true`.
+                        // Just in case...
+                        options.callbackQueue.execute {
+                            completionHandler?(
+                                .failure(KingfisherError.cacheError(reason: .imageNotExisting(key: key)))
+                            )
+                        }
+                    }
+                )
+            }
+            return true
+        }
+
+        return false
+    }
+}
+
+class RetrievingContext {
+
+    var options: KingfisherParsedOptionsInfo
+
+    let originalSource: Source
+    var propagationErrors: [PropagationError] = []
+
+    init(options: KingfisherParsedOptionsInfo, originalSource: Source) {
+        self.originalSource = originalSource
+        self.options = options
+    }
+
+    func popAlternativeSource() -> Source? {
+        guard var alternativeSources = options.alternativeSources, !alternativeSources.isEmpty else {
+            return nil
+        }
+        let nextSource = alternativeSources.removeFirst()
+        options.alternativeSources = alternativeSources
+        return nextSource
+    }
+
+    @discardableResult
+    func appendError(_ error: KingfisherError, to source: Source) -> [PropagationError] {
+        let item = PropagationError(source: source, error: error)
+        propagationErrors.append(item)
+        return propagationErrors
+    }
+}
+
+class CacheCallbackCoordinator {
+
+    enum State {
+        case idle
+        case imageCached
+        case originalImageCached
+        case done
+    }
+
+    enum Action {
+        case cacheInitiated
+        case cachingImage
+        case cachingOriginalImage
+    }
+
+    private let shouldWaitForCache: Bool
+    private let shouldCacheOriginal: Bool
+    private let stateQueue: DispatchQueue
+    private var threadSafeState: State = .idle
+
+    private (set) var state: State {
+        set { stateQueue.sync { threadSafeState = newValue } }
+        get { stateQueue.sync { threadSafeState } }
+    }
+
+    init(shouldWaitForCache: Bool, shouldCacheOriginal: Bool) {
+        self.shouldWaitForCache = shouldWaitForCache
+        self.shouldCacheOriginal = shouldCacheOriginal
+        let stateQueueName = "com.onevcat.Kingfisher.CacheCallbackCoordinator.stateQueue.\(UUID().uuidString)"
+        self.stateQueue = DispatchQueue(label: stateQueueName)
+    }
+
+    func apply(_ action: Action, trigger: () -> Void) {
+        switch (state, action) {
+        case (.done, _):
+            break
+
+        // From .idle
+        case (.idle, .cacheInitiated):
+            if !shouldWaitForCache {
+                state = .done
+                trigger()
+            }
+        case (.idle, .cachingImage):
+            if shouldCacheOriginal {
+                state = .imageCached
+            } else {
+                state = .done
+                trigger()
+            }
+        case (.idle, .cachingOriginalImage):
+            state = .originalImageCached
+
+        // From .imageCached
+        case (.imageCached, .cachingOriginalImage):
+            state = .done
+            trigger()
+
+        // From .originalImageCached
+        case (.originalImageCached, .cachingImage):
+            state = .done
+            trigger()
+
+        default:
+            assertionFailure("This case should not happen in CacheCallbackCoordinator: \(state) - \(action)")
+        }
+    }
+}

Pods/Kingfisher/Sources/General/KingfisherOptionsInfo.swift

@@ -0,0 +1,400 @@
+//
+//  KingfisherOptionsInfo.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 15/4/23.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+    
+
+/// KingfisherOptionsInfo is a typealias for [KingfisherOptionsInfoItem].
+/// You can use the enum of option item with value to control some behaviors of Kingfisher.
+public typealias KingfisherOptionsInfo = [KingfisherOptionsInfoItem]
+
+extension Array where Element == KingfisherOptionsInfoItem {
+    static let empty: KingfisherOptionsInfo = []
+}
+
+/// Represents the available option items could be used in `KingfisherOptionsInfo`.
+public enum KingfisherOptionsInfoItem {
+    
+    /// Kingfisher will use the associated `ImageCache` object when handling related operations,
+    /// including trying to retrieve the cached images and store the downloaded image to it.
+    case targetCache(ImageCache)
+    
+    /// The `ImageCache` for storing and retrieving original images. If `originalCache` is
+    /// contained in the options, it will be preferred for storing and retrieving original images.
+    /// If there is no `.originalCache` in the options, `.targetCache` will be used to store original images.
+    ///
+    /// When using KingfisherManager to download and store an image, if `cacheOriginalImage` is
+    /// applied in the option, the original image will be stored to this `originalCache`. At the
+    /// same time, if a requested final image (with processor applied) cannot be found in `targetCache`,
+    /// Kingfisher will try to search the original image to check whether it is already there. If found,
+    /// it will be used and applied with the given processor. It is an optimization for not downloading
+    /// the same image for multiple times.
+    case originalCache(ImageCache)
+    
+    /// Kingfisher will use the associated `ImageDownloader` object to download the requested images.
+    case downloader(ImageDownloader)
+
+    /// Member for animation transition when using `UIImageView`. Kingfisher will use the `ImageTransition` of
+    /// this enum to animate the image in if it is downloaded from web. The transition will not happen when the
+    /// image is retrieved from either memory or disk cache by default. If you need to do the transition even when
+    /// the image being retrieved from cache, set `.forceRefresh` as well.
+    case transition(ImageTransition)
+    
+    /// Associated `Float` value will be set as the priority of image download task. The value for it should be
+    /// between 0.0~1.0. If this option not set, the default value (`URLSessionTask.defaultPriority`) will be used.
+    case downloadPriority(Float)
+    
+    /// If set, Kingfisher will ignore the cache and try to start a download task for the image source.
+    case forceRefresh
+
+    /// If set, Kingfisher will try to retrieve the image from memory cache first. If the image is not in memory
+    /// cache, then it will ignore the disk cache but download the image again from network. This is useful when
+    /// you want to display a changeable image behind the same url at the same app session, while avoiding download
+    /// it for multiple times.
+    case fromMemoryCacheOrRefresh
+    
+    /// If set, setting the image to an image view will happen with transition even when retrieved from cache.
+    /// See `.transition` option for more.
+    case forceTransition
+    
+    /// If set, Kingfisher will only cache the value in memory but not in disk.
+    case cacheMemoryOnly
+    
+    /// If set, Kingfisher will wait for caching operation to be completed before calling the completion block.
+    case waitForCache
+    
+    /// If set, Kingfisher will only try to retrieve the image from cache, but not from network. If the image is not in
+    /// cache, the image retrieving will fail with the `KingfisherError.cacheError` with `.imageNotExisting` as its
+    /// reason.
+    case onlyFromCache
+    
+    /// Decode the image in background thread before using. It will decode the downloaded image data and do a off-screen
+    /// rendering to extract pixel information in background. This can speed up display, but will cost more time to
+    /// prepare the image for using.
+    case backgroundDecode
+
+    /// The associated value will be used as the target queue of dispatch callbacks when retrieving images from
+    /// cache. If not set, Kingfisher will use `.mainCurrentOrAsync` for callbacks.
+    ///
+    /// - Note:
+    /// This option does not affect the callbacks for UI related extension methods. You will always get the
+    /// callbacks called from main queue.
+    case callbackQueue(CallbackQueue)
+    
+    /// The associated value will be used as the scale factor when converting retrieved data to an image.
+    /// Specify the image scale, instead of your screen scale. You may need to set the correct scale when you dealing
+    /// with 2x or 3x retina images. Otherwise, Kingfisher will convert the data to image object at `scale` 1.0.
+    case scaleFactor(CGFloat)
+
+    /// Whether all the animated image data should be preloaded. Default is `false`, which means only following frames
+    /// will be loaded on need. If `true`, all the animated image data will be loaded and decoded into memory.
+    ///
+    /// This option is mainly used for back compatibility internally. You should not set it directly. Instead,
+    /// you should choose the image view class to control the GIF data loading. There are two classes in Kingfisher
+    /// support to display a GIF image. `AnimatedImageView` does not preload all data, it takes much less memory, but
+    /// uses more CPU when display. While a normal image view (`UIImageView` or `NSImageView`) loads all data at once,
+    /// which uses more memory but only decode image frames once.
+    case preloadAllAnimationData
+    
+    /// The `ImageDownloadRequestModifier` contained will be used to change the request before it being sent.
+    /// This is the last chance you can modify the image download request. You can modify the request for some
+    /// customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url mapping.
+    /// The original request will be sent without any modification by default.
+    case requestModifier(AsyncImageDownloadRequestModifier)
+    
+    /// The `ImageDownloadRedirectHandler` contained will be used to change the request before redirection.
+    /// This is the possibility you can modify the image download request during redirect. You can modify the request for
+    /// some customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url
+    /// mapping.
+    /// The original redirection request will be sent without any modification by default.
+    case redirectHandler(ImageDownloadRedirectHandler)
+    
+    /// Processor for processing when the downloading finishes, a processor will convert the downloaded data to an image
+    /// and/or apply some filter on it. If a cache is connected to the downloader (it happens when you are using
+    /// KingfisherManager or any of the view extension methods), the converted image will also be sent to cache as well.
+    /// If not set, the `DefaultImageProcessor.default` will be used.
+    case processor(ImageProcessor)
+    
+    /// Provides a `CacheSerializer` to convert some data to an image object for
+    /// retrieving from disk cache or vice versa for storing to disk cache.
+    /// If not set, the `DefaultCacheSerializer.default` will be used.
+    case cacheSerializer(CacheSerializer)
+
+    /// An `ImageModifier` is for modifying an image as needed right before it is used. If the image was fetched
+    /// directly from the downloader, the modifier will run directly after the `ImageProcessor`. If the image is being
+    /// fetched from a cache, the modifier will run after the `CacheSerializer`.
+    ///
+    /// Use `ImageModifier` when you need to set properties that do not persist when caching the image on a concrete
+    /// type of `Image`, such as the `renderingMode` or the `alignmentInsets` of `UIImage`.
+    case imageModifier(ImageModifier)
+    
+    /// Keep the existing image of image view while setting another image to it.
+    /// By setting this option, the placeholder image parameter of image view extension method
+    /// will be ignored and the current image will be kept while loading or downloading the new image.
+    case keepCurrentImageWhileLoading
+    
+    /// If set, Kingfisher will only load the first frame from an animated image file as a single image.
+    /// Loading an animated images may take too much memory. It will be useful when you want to display a
+    /// static preview of the first frame from an animated image.
+    ///
+    /// This option will be ignored if the target image is not animated image data.
+    case onlyLoadFirstFrame
+    
+    /// If set and an `ImageProcessor` is used, Kingfisher will try to cache both the final result and original
+    /// image. Kingfisher will have a chance to use the original image when another processor is applied to the same
+    /// resource, instead of downloading it again. You can use `.originalCache` to specify a cache or the original
+    /// images if necessary.
+    ///
+    /// The original image will be only cached to disk storage.
+    case cacheOriginalImage
+    
+    /// If set and an image retrieving error occurred Kingfisher will set provided image (or empty)
+    /// in place of requested one. It's useful when you don't want to show placeholder
+    /// during loading time but wants to use some default image when requests will be failed.
+    case onFailureImage(KFCrossPlatformImage?)
+    
+    /// If set and used in `ImagePrefetcher`, the prefetching operation will load the images into memory storage
+    /// aggressively. By default this is not contained in the options, that means if the requested image is already
+    /// in disk cache, Kingfisher will not try to load it to memory.
+    case alsoPrefetchToMemory
+    
+    /// If set, the disk storage loading will happen in the same calling queue. By default, disk storage file loading
+    /// happens in its own queue with an asynchronous dispatch behavior. Although it provides better non-blocking disk
+    /// loading performance, it also causes a flickering when you reload an image from disk, if the image view already
+    /// has an image set.
+    ///
+    /// Set this options will stop that flickering by keeping all loading in the same queue (typically the UI queue
+    /// if you are using Kingfisher's extension methods to set an image), with a tradeoff of loading performance.
+    case loadDiskFileSynchronously
+
+    /// Options to control the writing of data to disk storage
+    /// If set, options will be passed the store operation for a new files.
+    case diskStoreWriteOptions(Data.WritingOptions)
+
+    /// The expiration setting for memory cache. By default, the underlying `MemoryStorage.Backend` uses the
+    /// expiration in its config for all items. If set, the `MemoryStorage.Backend` will use this associated
+    /// value to overwrite the config setting for this caching item.
+    case memoryCacheExpiration(StorageExpiration)
+    
+    /// The expiration extending setting for memory cache. The item expiration time will be incremented by this
+    /// value after access.
+    /// By default, the underlying `MemoryStorage.Backend` uses the initial cache expiration as extending
+    /// value: .cacheTime.
+    ///
+    /// To disable extending option at all add memoryCacheAccessExtendingExpiration(.none) to options.
+    case memoryCacheAccessExtendingExpiration(ExpirationExtending)
+    
+    /// The expiration setting for disk cache. By default, the underlying `DiskStorage.Backend` uses the
+    /// expiration in its config for all items. If set, the `DiskStorage.Backend` will use this associated
+    /// value to overwrite the config setting for this caching item.
+    case diskCacheExpiration(StorageExpiration)
+
+    /// The expiration extending setting for disk cache. The item expiration time will be incremented by this value after access.
+    /// By default, the underlying `DiskStorage.Backend` uses the initial cache expiration as extending value: .cacheTime.
+    /// To disable extending option at all add diskCacheAccessExtendingExpiration(.none) to options.
+    case diskCacheAccessExtendingExpiration(ExpirationExtending)
+    
+    /// Decides on which queue the image processing should happen. By default, Kingfisher uses a pre-defined serial
+    /// queue to process images. Use this option to change this behavior. For example, specify a `.mainCurrentOrAsync`
+    /// to let the image be processed in main queue to prevent a possible flickering (but with a possibility of
+    /// blocking the UI, especially if the processor needs a lot of time to run).
+    case processingQueue(CallbackQueue)
+    
+    /// Enable progressive image loading, Kingfisher will use the associated `ImageProgressive` value to process the
+    /// progressive JPEG data and display it in a progressive way.
+    case progressiveJPEG(ImageProgressive)
+
+    /// The alternative sources will be used when the original input `Source` fails. The `Source`s in the associated
+    /// array will be used to start a new image loading task if the previous task fails due to an error. The image
+    /// source loading process will stop as soon as a source is loaded successfully. If all `[Source]`s are used but
+    /// the loading is still failing, an `imageSettingError` with `alternativeSourcesExhausted` as its reason will be
+    /// thrown out.
+    ///
+    /// This option is useful if you want to implement a fallback solution for setting image.
+    ///
+    /// User cancellation will not trigger the alternative source loading.
+    case alternativeSources([Source])
+
+    /// Provide a retry strategy which will be used when something gets wrong during the image retrieving process from
+    /// `KingfisherManager`. You can define a strategy by create a type conforming to the `RetryStrategy` protocol.
+    ///
+    /// - Note:
+    ///
+    /// All extension methods of Kingfisher (`kf` extensions on `UIImageView` or `UIButton`) retrieve images through
+    /// `KingfisherManager`, so the retry strategy also applies when using them. However, this option does not apply
+    /// when pass to an `ImageDownloader` or `ImageCache`.
+    ///
+    case retryStrategy(RetryStrategy)
+
+    /// The `Source` should be loaded when user enables Low Data Mode and the original source fails with an
+    /// `NSURLErrorNetworkUnavailableReason.constrained` error. When this option is set, the
+    /// `allowsConstrainedNetworkAccess` property of the request for the original source will be set to `false` and the
+    /// `Source` in associated value will be used to retrieve the image for low data mode. Usually, you can provide a
+    /// low-resolution version of your image or a local image provider to display a placeholder.
+    ///
+    /// If not set or the `source` is `nil`, the device Low Data Mode will be ignored and the original source will
+    /// be loaded following the system default behavior, in a normal way.
+    case lowDataMode(Source?)
+}
+
+// Improve performance by parsing the input `KingfisherOptionsInfo` (self) first.
+// So we can prevent the iterating over the options array again and again.
+/// The parsed options info used across Kingfisher methods. Each property in this type corresponds a case member
+/// in `KingfisherOptionsInfoItem`. When a `KingfisherOptionsInfo` sent to Kingfisher related methods, it will be
+/// parsed and converted to a `KingfisherParsedOptionsInfo` first, and pass through the internal methods.
+public struct KingfisherParsedOptionsInfo {
+
+    public var targetCache: ImageCache? = nil
+    public var originalCache: ImageCache? = nil
+    public var downloader: ImageDownloader? = nil
+    public var transition: ImageTransition = .none
+    public var downloadPriority: Float = URLSessionTask.defaultPriority
+    public var forceRefresh = false
+    public var fromMemoryCacheOrRefresh = false
+    public var forceTransition = false
+    public var cacheMemoryOnly = false
+    public var waitForCache = false
+    public var onlyFromCache = false
+    public var backgroundDecode = false
+    public var preloadAllAnimationData = false
+    public var callbackQueue: CallbackQueue = .mainCurrentOrAsync
+    public var scaleFactor: CGFloat = 1.0
+    public var requestModifier: AsyncImageDownloadRequestModifier? = nil
+    public var redirectHandler: ImageDownloadRedirectHandler? = nil
+    public var processor: ImageProcessor = DefaultImageProcessor.default
+    public var imageModifier: ImageModifier? = nil
+    public var cacheSerializer: CacheSerializer = DefaultCacheSerializer.default
+    public var keepCurrentImageWhileLoading = false
+    public var onlyLoadFirstFrame = false
+    public var cacheOriginalImage = false
+    public var onFailureImage: Optional<KFCrossPlatformImage?> = .none
+    public var alsoPrefetchToMemory = false
+    public var loadDiskFileSynchronously = false
+    public var diskStoreWriteOptions: Data.WritingOptions = []
+    public var memoryCacheExpiration: StorageExpiration? = nil
+    public var memoryCacheAccessExtendingExpiration: ExpirationExtending = .cacheTime
+    public var diskCacheExpiration: StorageExpiration? = nil
+    public var diskCacheAccessExtendingExpiration: ExpirationExtending = .cacheTime
+    public var processingQueue: CallbackQueue? = nil
+    public var progressiveJPEG: ImageProgressive? = nil
+    public var alternativeSources: [Source]? = nil
+    public var retryStrategy: RetryStrategy? = nil
+    public var lowDataModeSource: Source? = nil
+
+    var onDataReceived: [DataReceivingSideEffect]? = nil
+    
+    public init(_ info: KingfisherOptionsInfo?) {
+        guard let info = info else { return }
+        for option in info {
+            switch option {
+            case .targetCache(let value): targetCache = value
+            case .originalCache(let value): originalCache = value
+            case .downloader(let value): downloader = value
+            case .transition(let value): transition = value
+            case .downloadPriority(let value): downloadPriority = value
+            case .forceRefresh: forceRefresh = true
+            case .fromMemoryCacheOrRefresh: fromMemoryCacheOrRefresh = true
+            case .forceTransition: forceTransition = true
+            case .cacheMemoryOnly: cacheMemoryOnly = true
+            case .waitForCache: waitForCache = true
+            case .onlyFromCache: onlyFromCache = true
+            case .backgroundDecode: backgroundDecode = true
+            case .preloadAllAnimationData: preloadAllAnimationData = true
+            case .callbackQueue(let value): callbackQueue = value
+            case .scaleFactor(let value): scaleFactor = value
+            case .requestModifier(let value): requestModifier = value
+            case .redirectHandler(let value): redirectHandler = value
+            case .processor(let value): processor = value
+            case .imageModifier(let value): imageModifier = value
+            case .cacheSerializer(let value): cacheSerializer = value
+            case .keepCurrentImageWhileLoading: keepCurrentImageWhileLoading = true
+            case .onlyLoadFirstFrame: onlyLoadFirstFrame = true
+            case .cacheOriginalImage: cacheOriginalImage = true
+            case .onFailureImage(let value): onFailureImage = .some(value)
+            case .alsoPrefetchToMemory: alsoPrefetchToMemory = true
+            case .loadDiskFileSynchronously: loadDiskFileSynchronously = true
+            case .diskStoreWriteOptions(let options): diskStoreWriteOptions = options
+            case .memoryCacheExpiration(let expiration): memoryCacheExpiration = expiration
+            case .memoryCacheAccessExtendingExpiration(let expirationExtending): memoryCacheAccessExtendingExpiration = expirationExtending
+            case .diskCacheExpiration(let expiration): diskCacheExpiration = expiration
+            case .diskCacheAccessExtendingExpiration(let expirationExtending): diskCacheAccessExtendingExpiration = expirationExtending
+            case .processingQueue(let queue): processingQueue = queue
+            case .progressiveJPEG(let value): progressiveJPEG = value
+            case .alternativeSources(let sources): alternativeSources = sources
+            case .retryStrategy(let strategy): retryStrategy = strategy
+            case .lowDataMode(let source): lowDataModeSource = source
+            }
+        }
+
+        if originalCache == nil {
+            originalCache = targetCache
+        }
+    }
+}
+
+extension KingfisherParsedOptionsInfo {
+    var imageCreatingOptions: ImageCreatingOptions {
+        return ImageCreatingOptions(
+            scale: scaleFactor,
+            duration: 0.0,
+            preloadAll: preloadAllAnimationData,
+            onlyFirstFrame: onlyLoadFirstFrame)
+    }
+}
+
+protocol DataReceivingSideEffect: AnyObject {
+    var onShouldApply: () -> Bool { get set }
+    func onDataReceived(_ session: URLSession, task: SessionDataTask, data: Data)
+}
+
+class ImageLoadingProgressSideEffect: DataReceivingSideEffect {
+
+    var onShouldApply: () -> Bool = { return true }
+    
+    let block: DownloadProgressBlock
+
+    init(_ block: @escaping DownloadProgressBlock) {
+        self.block = block
+    }
+
+    func onDataReceived(_ session: URLSession, task: SessionDataTask, data: Data) {
+        guard self.onShouldApply() else { return }
+        guard let expectedContentLength = task.task.response?.expectedContentLength,
+                  expectedContentLength != -1 else
+        {
+            return
+        }
+
+        let dataLength = Int64(task.mutableData.count)
+        DispatchQueue.main.async {
+            self.block(dataLength, expectedContentLength)
+        }
+    }
+}

Pods/Kingfisher/Sources/Image/Filter.swift

@@ -0,0 +1,152 @@
+//
+//  Filter.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2016/08/31.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if !os(watchOS)
+
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+import CoreImage
+
+// Reuse the same CI Context for all CI drawing.
+private let ciContext = CIContext(options: nil)
+
+/// Represents the type of transformer method, which will be used in to provide a `Filter`.
+public typealias Transformer = (CIImage) -> CIImage?
+
+/// Represents a processor based on a `CIImage` `Filter`.
+/// It requires a filter to create an `ImageProcessor`.
+public protocol CIImageProcessor: ImageProcessor {
+    var filter: Filter { get }
+}
+
+extension CIImageProcessor {
+    
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            return image.kf.apply(filter)
+        case .data:
+            return (DefaultImageProcessor.default |> self).process(item: item, options: options)
+        }
+    }
+}
+
+/// A wrapper struct for a `Transformer` of CIImage filters. A `Filter`
+/// value could be used to create a `CIImage` processor.
+public struct Filter {
+    
+    let transform: Transformer
+
+    public init(transform: @escaping Transformer) {
+        self.transform = transform
+    }
+    
+    /// Tint filter which will apply a tint color to images.
+    public static var tint: (KFCrossPlatformColor) -> Filter = {
+        color in
+        Filter {
+            input in
+            
+            let colorFilter = CIFilter(name: "CIConstantColorGenerator")!
+            colorFilter.setValue(CIColor(color: color), forKey: kCIInputColorKey)
+            
+            let filter = CIFilter(name: "CISourceOverCompositing")!
+            
+            let colorImage = colorFilter.outputImage
+            filter.setValue(colorImage, forKey: kCIInputImageKey)
+            filter.setValue(input, forKey: kCIInputBackgroundImageKey)
+            
+            return filter.outputImage?.cropped(to: input.extent)
+        }
+    }
+    
+    /// Represents color control elements. It is a tuple of
+    /// `(brightness, contrast, saturation, inputEV)`
+    public typealias ColorElement = (CGFloat, CGFloat, CGFloat, CGFloat)
+    
+    /// Color control filter which will apply color control change to images.
+    public static var colorControl: (ColorElement) -> Filter = { arg -> Filter in
+        let (brightness, contrast, saturation, inputEV) = arg
+        return Filter { input in
+            let paramsColor = [kCIInputBrightnessKey: brightness,
+                               kCIInputContrastKey: contrast,
+                               kCIInputSaturationKey: saturation]
+            let blackAndWhite = input.applyingFilter("CIColorControls", parameters: paramsColor)
+            let paramsExposure = [kCIInputEVKey: inputEV]
+            return blackAndWhite.applyingFilter("CIExposureAdjust", parameters: paramsExposure)
+        }
+    }
+}
+
+extension KingfisherWrapper where Base: KFCrossPlatformImage {
+
+    /// Applies a `Filter` containing `CIImage` transformer to `self`.
+    ///
+    /// - Parameter filter: The filter used to transform `self`.
+    /// - Returns: A transformed image by input `Filter`.
+    ///
+    /// - Note:
+    ///    Only CG-based images are supported. If any error happens
+    ///    during transforming, `self` will be returned.
+    public func apply(_ filter: Filter) -> KFCrossPlatformImage {
+        
+        guard let cgImage = cgImage else {
+            assertionFailure("[Kingfisher] Tint image only works for CG-based image.")
+            return base
+        }
+        
+        let inputImage = CIImage(cgImage: cgImage)
+        guard let outputImage = filter.transform(inputImage) else {
+            return base
+        }
+
+        guard let result = ciContext.createCGImage(outputImage, from: outputImage.extent) else {
+            assertionFailure("[Kingfisher] Can not make an tint image within context.")
+            return base
+        }
+        
+        #if os(macOS)
+            return fixedForRetinaPixel(cgImage: result, to: size)
+        #else
+            return KFCrossPlatformImage(cgImage: result, scale: base.scale, orientation: base.imageOrientation)
+        #endif
+    }
+
+}
+
+#endif

Pods/Kingfisher/Sources/Image/GIFAnimatedImage.swift

@@ -0,0 +1,177 @@
+//
+//  AnimatedImage.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2018/09/26.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+import ImageIO
+
+/// Represents a set of image creating options used in Kingfisher.
+public struct ImageCreatingOptions {
+
+    /// The target scale of image needs to be created.
+    public let scale: CGFloat
+
+    /// The expected animation duration if an animated image being created.
+    public let duration: TimeInterval
+
+    /// For an animated image, whether or not all frames should be loaded before displaying.
+    public let preloadAll: Bool
+
+    /// For an animated image, whether or not only the first image should be
+    /// loaded as a static image. It is useful for preview purpose of an animated image.
+    public let onlyFirstFrame: Bool
+    
+    /// Creates an `ImageCreatingOptions` object.
+    ///
+    /// - Parameters:
+    ///   - scale: The target scale of image needs to be created. Default is `1.0`.
+    ///   - duration: The expected animation duration if an animated image being created.
+    ///               A value less or equal to `0.0` means the animated image duration will
+    ///               be determined by the frame data. Default is `0.0`.
+    ///   - preloadAll: For an animated image, whether or not all frames should be loaded before displaying.
+    ///                 Default is `false`.
+    ///   - onlyFirstFrame: For an animated image, whether or not only the first image should be
+    ///                     loaded as a static image. It is useful for preview purpose of an animated image.
+    ///                     Default is `false`.
+    public init(
+        scale: CGFloat = 1.0,
+        duration: TimeInterval = 0.0,
+        preloadAll: Bool = false,
+        onlyFirstFrame: Bool = false)
+    {
+        self.scale = scale
+        self.duration = duration
+        self.preloadAll = preloadAll
+        self.onlyFirstFrame = onlyFirstFrame
+    }
+}
+
+/// Represents the decoding for a GIF image. This class extracts frames from an `imageSource`, then
+/// hold the images for later use.
+public class GIFAnimatedImage {
+    let images: [KFCrossPlatformImage]
+    let duration: TimeInterval
+    
+    init?(from frameSource: ImageFrameSource, options: ImageCreatingOptions) {
+        let frameCount = frameSource.frameCount
+        var images = [KFCrossPlatformImage]()
+        var gifDuration = 0.0
+        
+        for i in 0 ..< frameCount {
+            guard let imageRef = frameSource.frame(at: i) else {
+                return nil
+            }
+            
+            if frameCount == 1 {
+                gifDuration = .infinity
+            } else {
+                // Get current animated GIF frame duration
+                gifDuration += frameSource.duration(at: i)
+            }
+            images.append(KingfisherWrapper.image(cgImage: imageRef, scale: options.scale, refImage: nil))
+            if options.onlyFirstFrame { break }
+        }
+        self.images = images
+        self.duration = gifDuration
+    }
+    
+    convenience init?(from imageSource: CGImageSource, for info: [String: Any], options: ImageCreatingOptions) {
+        let frameSource = CGImageFrameSource(data: nil, imageSource: imageSource, options: info)
+        self.init(from: frameSource, options: options)
+    }
+    
+    /// Calculates frame duration for a gif frame out of the kCGImagePropertyGIFDictionary dictionary.
+    public static func getFrameDuration(from gifInfo: [String: Any]?) -> TimeInterval {
+        let defaultFrameDuration = 0.1
+        guard let gifInfo = gifInfo else { return defaultFrameDuration }
+        
+        let unclampedDelayTime = gifInfo[kCGImagePropertyGIFUnclampedDelayTime as String] as? NSNumber
+        let delayTime = gifInfo[kCGImagePropertyGIFDelayTime as String] as? NSNumber
+        let duration = unclampedDelayTime ?? delayTime
+        
+        guard let frameDuration = duration else { return defaultFrameDuration }
+        return frameDuration.doubleValue > 0.011 ? frameDuration.doubleValue : defaultFrameDuration
+    }
+
+    /// Calculates frame duration at a specific index for a gif from an `imageSource`.
+    public static func getFrameDuration(from imageSource: CGImageSource, at index: Int) -> TimeInterval {
+        guard let properties = CGImageSourceCopyPropertiesAtIndex(imageSource, index, nil)
+            as? [String: Any] else { return 0.0 }
+
+        let gifInfo = properties[kCGImagePropertyGIFDictionary as String] as? [String: Any]
+        return getFrameDuration(from: gifInfo)
+    }
+}
+
+/// Represents a frame source for animated image
+public protocol ImageFrameSource {
+    /// Source data associated with this frame source.
+    var data: Data? { get }
+    
+    /// Count of total frames in this frame source.
+    var frameCount: Int { get }
+    
+    /// Retrieves the frame at a specific index. The result image is expected to be
+    /// no larger than `maxSize`. If the index is invalid, implementors should return `nil`.
+    func frame(at index: Int, maxSize: CGSize?) -> CGImage?
+    
+    /// Retrieves the duration at a specific index. If the index is invalid, implementors should return `0.0`.
+    func duration(at index: Int) -> TimeInterval
+}
+
+public extension ImageFrameSource {
+    /// Retrieves the frame at a specific index. If the index is invalid, implementors should return `nil`.
+    func frame(at index: Int) -> CGImage? {
+        return frame(at: index, maxSize: nil)
+    }
+}
+
+struct CGImageFrameSource: ImageFrameSource {
+    let data: Data?
+    let imageSource: CGImageSource
+    let options: [String: Any]?
+    
+    var frameCount: Int {
+        return CGImageSourceGetCount(imageSource)
+    }
+
+    func frame(at index: Int, maxSize: CGSize?) -> CGImage? {
+        var options = self.options as? [CFString: Any]
+        if let maxSize = maxSize, maxSize != .zero {
+            options = (options ?? [:]).merging([
+                kCGImageSourceCreateThumbnailFromImageIfAbsent: true,
+                kCGImageSourceCreateThumbnailWithTransform: true,
+                kCGImageSourceShouldCacheImmediately: true,
+                kCGImageSourceThumbnailMaxPixelSize: max(maxSize.width, maxSize.height)
+            ], uniquingKeysWith: { $1 })
+        }
+        return CGImageSourceCreateImageAtIndex(imageSource, index, options as CFDictionary?)
+    }
+
+    func duration(at index: Int) -> TimeInterval {
+        return GIFAnimatedImage.getFrameDuration(from: imageSource, at: index)
+    }
+}
+

Pods/Kingfisher/Sources/Image/GraphicsContext.swift

@@ -0,0 +1,88 @@
+//
+//  GraphicsContext.swift
+//  Kingfisher
+//
+//  Created by taras on 19/04/2021.
+//
+//  Copyright (c) 2021 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if canImport(AppKit) && !targetEnvironment(macCatalyst)
+import AppKit
+#endif
+#if canImport(UIKit)
+import UIKit
+#endif
+
+enum GraphicsContext {
+    static func begin(size: CGSize, scale: CGFloat) {
+        #if os(macOS)
+        NSGraphicsContext.saveGraphicsState()
+        #else
+        UIGraphicsBeginImageContextWithOptions(size, false, scale)
+        #endif
+    }
+    
+    static func current(size: CGSize, scale: CGFloat, inverting: Bool, cgImage: CGImage?) -> CGContext? {
+        #if os(macOS)
+        guard let rep = NSBitmapImageRep(
+            bitmapDataPlanes: nil,
+            pixelsWide: Int(size.width),
+            pixelsHigh: Int(size.height),
+            bitsPerSample: cgImage?.bitsPerComponent ?? 8,
+            samplesPerPixel: 4,
+            hasAlpha: true,
+            isPlanar: false,
+            colorSpaceName: .calibratedRGB,
+            bytesPerRow: 0,
+            bitsPerPixel: 0) else
+        {
+            assertionFailure("[Kingfisher] Image representation cannot be created.")
+            return nil
+        }
+        rep.size = size
+        guard let context = NSGraphicsContext(bitmapImageRep: rep) else {
+            assertionFailure("[Kingfisher] Image context cannot be created.")
+            return nil
+        }
+        
+        NSGraphicsContext.current = context
+        return context.cgContext
+        #else
+        guard let context = UIGraphicsGetCurrentContext() else {
+            return nil
+        }
+        if inverting { // If drawing a CGImage, we need to make context flipped.
+            context.scaleBy(x: 1.0, y: -1.0)
+            context.translateBy(x: 0, y: -size.height)
+        }
+        return context
+        #endif
+    }
+    
+    static func end() {
+        #if os(macOS)
+        NSGraphicsContext.restoreGraphicsState()
+        #else
+        UIGraphicsEndImageContext()
+        #endif
+    }
+}
+

Pods/Kingfisher/Sources/Image/Image.swift

@@ -0,0 +1,426 @@
+//
+//  Image.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 16/1/6.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+
+#if os(macOS)
+import AppKit
+private var imagesKey: Void?
+private var durationKey: Void?
+#else
+import UIKit
+import MobileCoreServices
+private var imageSourceKey: Void?
+#endif
+
+#if !os(watchOS)
+import CoreImage
+#endif
+
+import CoreGraphics
+import ImageIO
+
+#if canImport(UniformTypeIdentifiers)
+import UniformTypeIdentifiers
+#endif
+
+private var animatedImageDataKey: Void?
+private var imageFrameCountKey: Void?
+
+// MARK: - Image Properties
+extension KingfisherWrapper where Base: KFCrossPlatformImage {
+    private(set) var animatedImageData: Data? {
+        get { return getAssociatedObject(base, &animatedImageDataKey) }
+        set { setRetainedAssociatedObject(base, &animatedImageDataKey, newValue) }
+    }
+    
+    public var imageFrameCount: Int? {
+        get { return getAssociatedObject(base, &imageFrameCountKey) }
+        set { setRetainedAssociatedObject(base, &imageFrameCountKey, newValue) }
+    }
+    
+    #if os(macOS)
+    var cgImage: CGImage? {
+        return base.cgImage(forProposedRect: nil, context: nil, hints: nil)
+    }
+    
+    var scale: CGFloat {
+        return 1.0
+    }
+    
+    private(set) var images: [KFCrossPlatformImage]? {
+        get { return getAssociatedObject(base, &imagesKey) }
+        set { setRetainedAssociatedObject(base, &imagesKey, newValue) }
+    }
+    
+    private(set) var duration: TimeInterval {
+        get { return getAssociatedObject(base, &durationKey) ?? 0.0 }
+        set { setRetainedAssociatedObject(base, &durationKey, newValue) }
+    }
+    
+    var size: CGSize {
+        return base.representations.reduce(.zero) { size, rep in
+            let width = max(size.width, CGFloat(rep.pixelsWide))
+            let height = max(size.height, CGFloat(rep.pixelsHigh))
+            return CGSize(width: width, height: height)
+        }
+    }
+    #else
+    var cgImage: CGImage? { return base.cgImage }
+    var scale: CGFloat { return base.scale }
+    var images: [KFCrossPlatformImage]? { return base.images }
+    var duration: TimeInterval { return base.duration }
+    var size: CGSize { return base.size }
+    
+    /// The image source reference of current image.
+    public var imageSource: CGImageSource? {
+        get {
+            guard let frameSource = frameSource as? CGImageFrameSource else { return nil }
+            return frameSource.imageSource
+        }
+    }
+    
+    /// The custom frame source of current image.
+    public private(set) var frameSource: ImageFrameSource? {
+        get { return getAssociatedObject(base, &imageSourceKey) }
+        set { setRetainedAssociatedObject(base, &imageSourceKey, newValue) }
+    }
+    #endif
+
+    // Bitmap memory cost with bytes.
+    var cost: Int {
+        let pixel = Int(size.width * size.height * scale * scale)
+        guard let cgImage = cgImage else {
+            return pixel * 4
+        }
+        let bytesPerPixel = cgImage.bitsPerPixel / 8
+        guard let imageCount = images?.count else {
+            return pixel * bytesPerPixel
+        }
+        return pixel * bytesPerPixel * imageCount
+    }
+}
+
+// MARK: - Image Conversion
+extension KingfisherWrapper where Base: KFCrossPlatformImage {
+    #if os(macOS)
+    static func image(cgImage: CGImage, scale: CGFloat, refImage: KFCrossPlatformImage?) -> KFCrossPlatformImage {
+        return KFCrossPlatformImage(cgImage: cgImage, size: .zero)
+    }
+    
+    /// Normalize the image. This getter does nothing on macOS but return the image itself.
+    public var normalized: KFCrossPlatformImage { return base }
+
+    #else
+    /// Creating an image from a give `CGImage` at scale and orientation for refImage. The method signature is for
+    /// compatibility of macOS version.
+    static func image(cgImage: CGImage, scale: CGFloat, refImage: KFCrossPlatformImage?) -> KFCrossPlatformImage {
+        return KFCrossPlatformImage(cgImage: cgImage, scale: scale, orientation: refImage?.imageOrientation ?? .up)
+    }
+    
+    /// Returns normalized image for current `base` image.
+    /// This method will try to redraw an image with orientation and scale considered.
+    public var normalized: KFCrossPlatformImage {
+        // prevent animated image (GIF) lose it's images
+        guard images == nil else { return base.copy() as! KFCrossPlatformImage }
+        // No need to do anything if already up
+        guard base.imageOrientation != .up else { return base.copy() as! KFCrossPlatformImage }
+
+        return draw(to: size, inverting: true, refImage: KFCrossPlatformImage()) {
+            fixOrientation(in: $0)
+            return true
+        }
+    }
+
+    func fixOrientation(in context: CGContext) {
+
+        var transform = CGAffineTransform.identity
+
+        let orientation = base.imageOrientation
+
+        switch orientation {
+        case .down, .downMirrored:
+            transform = transform.translatedBy(x: size.width, y: size.height)
+            transform = transform.rotated(by: .pi)
+        case .left, .leftMirrored:
+            transform = transform.translatedBy(x: size.width, y: 0)
+            transform = transform.rotated(by: .pi / 2.0)
+        case .right, .rightMirrored:
+            transform = transform.translatedBy(x: 0, y: size.height)
+            transform = transform.rotated(by: .pi / -2.0)
+        case .up, .upMirrored:
+            break
+        #if compiler(>=5)
+        @unknown default:
+            break
+        #endif
+        }
+
+        //Flip image one more time if needed to, this is to prevent flipped image
+        switch orientation {
+        case .upMirrored, .downMirrored:
+            transform = transform.translatedBy(x: size.width, y: 0)
+            transform = transform.scaledBy(x: -1, y: 1)
+        case .leftMirrored, .rightMirrored:
+            transform = transform.translatedBy(x: size.height, y: 0)
+            transform = transform.scaledBy(x: -1, y: 1)
+        case .up, .down, .left, .right:
+            break
+        #if compiler(>=5)
+        @unknown default:
+            break
+        #endif
+        }
+
+        context.concatenate(transform)
+        switch orientation {
+        case .left, .leftMirrored, .right, .rightMirrored:
+            context.draw(cgImage!, in: CGRect(x: 0, y: 0, width: size.height, height: size.width))
+        default:
+            context.draw(cgImage!, in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
+        }
+    }
+    #endif
+}
+
+// MARK: - Image Representation
+extension KingfisherWrapper where Base: KFCrossPlatformImage {
+    /// Returns PNG representation of `base` image.
+    ///
+    /// - Returns: PNG data of image.
+    public func pngRepresentation() -> Data? {
+        #if os(macOS)
+            guard let cgImage = cgImage else {
+                return nil
+            }
+            let rep = NSBitmapImageRep(cgImage: cgImage)
+            return rep.representation(using: .png, properties: [:])
+        #else
+            return base.pngData()
+        #endif
+    }
+
+    /// Returns JPEG representation of `base` image.
+    ///
+    /// - Parameter compressionQuality: The compression quality when converting image to JPEG data.
+    /// - Returns: JPEG data of image.
+    public func jpegRepresentation(compressionQuality: CGFloat) -> Data? {
+        #if os(macOS)
+            guard let cgImage = cgImage else {
+                return nil
+            }
+            let rep = NSBitmapImageRep(cgImage: cgImage)
+            return rep.representation(using:.jpeg, properties: [.compressionFactor: compressionQuality])
+        #else
+            return base.jpegData(compressionQuality: compressionQuality)
+        #endif
+    }
+
+    /// Returns GIF representation of `base` image.
+    ///
+    /// - Returns: Original GIF data of image.
+    public func gifRepresentation() -> Data? {
+        return animatedImageData
+    }
+
+    /// Returns a data representation for `base` image, with the `format` as the format indicator.
+    /// - Parameters:
+    ///   - format: The format in which the output data should be. If `unknown`, the `base` image will be
+    ///             converted in the PNG representation.
+    ///   - compressionQuality: The compression quality when converting image to a lossy format data.
+    ///
+    /// - Returns: The output data representing.
+    public func data(format: ImageFormat, compressionQuality: CGFloat = 1.0) -> Data? {
+        return autoreleasepool { () -> Data? in
+            let data: Data?
+            switch format {
+            case .PNG: data = pngRepresentation()
+            case .JPEG: data = jpegRepresentation(compressionQuality: compressionQuality)
+            case .GIF: data = gifRepresentation()
+            case .unknown: data = normalized.kf.pngRepresentation()
+            }
+            
+            return data
+        }
+    }
+}
+
+// MARK: - Creating Images
+extension KingfisherWrapper where Base: KFCrossPlatformImage {
+
+    /// Creates an animated image from a given data and options. Currently only GIF data is supported.
+    ///
+    /// - Parameters:
+    ///   - data: The animated image data.
+    ///   - options: Options to use when creating the animated image.
+    /// - Returns: An `Image` object represents the animated image. It is in form of an array of image frames with a
+    ///            certain duration. `nil` if anything wrong when creating animated image.
+    public static func animatedImage(data: Data, options: ImageCreatingOptions) -> KFCrossPlatformImage? {
+        #if os(visionOS)
+        let info: [String: Any] = [
+            kCGImageSourceShouldCache as String: true,
+            kCGImageSourceTypeIdentifierHint as String: UTType.gif.identifier
+        ]
+        #else
+        let info: [String: Any] = [
+            kCGImageSourceShouldCache as String: true,
+            kCGImageSourceTypeIdentifierHint as String: kUTTypeGIF
+        ]
+        #endif
+        
+        guard let imageSource = CGImageSourceCreateWithData(data as CFData, info as CFDictionary) else {
+            return nil
+        }
+        let frameSource = CGImageFrameSource(data: data, imageSource: imageSource, options: info)
+        #if os(macOS)
+        let baseImage = KFCrossPlatformImage(data: data)
+        #else
+        let baseImage = KFCrossPlatformImage(data: data, scale: options.scale)
+        #endif
+        return animatedImage(source: frameSource, options: options, baseImage: baseImage)
+    }
+    
+    /// Creates an animated image from a given frame source.
+    ///
+    /// - Parameters:
+    ///   - source: The frame source to create animated image from.
+    ///   - options: Options to use when creating the animated image.
+    ///   - baseImage: An optional image object to be used as the key frame of the animated image. If `nil`, the first
+    ///                frame of the `source` will be used.
+    /// - Returns: An `Image` object represents the animated image. It is in form of an array of image frames with a
+    ///           certain duration. `nil` if anything wrong when creating animated image.
+    public static func animatedImage(source: ImageFrameSource, options: ImageCreatingOptions, baseImage: KFCrossPlatformImage? = nil) -> KFCrossPlatformImage? {
+        #if os(macOS)
+        guard let animatedImage = GIFAnimatedImage(from: source, options: options) else {
+            return nil
+        }
+        var image: KFCrossPlatformImage?
+        if options.onlyFirstFrame {
+            image = animatedImage.images.first
+        } else {
+            if let baseImage = baseImage {
+                image = baseImage
+            } else {
+                image = animatedImage.images.first
+            }
+            var kf = image?.kf
+            kf?.images = animatedImage.images
+            kf?.duration = animatedImage.duration
+        }
+        image?.kf.animatedImageData = source.data
+        image?.kf.imageFrameCount = source.frameCount
+        return image
+        #else
+        
+        var image: KFCrossPlatformImage?
+        if options.preloadAll || options.onlyFirstFrame {
+            // Use `images` image if you want to preload all animated data
+            guard let animatedImage = GIFAnimatedImage(from: source, options: options) else {
+                return nil
+            }
+            if options.onlyFirstFrame {
+                image = animatedImage.images.first
+            } else {
+                let duration = options.duration <= 0.0 ? animatedImage.duration : options.duration
+                image = .animatedImage(with: animatedImage.images, duration: duration)
+            }
+            image?.kf.animatedImageData = source.data
+        } else {
+            if let baseImage = baseImage {
+                image = baseImage
+            } else {
+                guard let firstFrame = source.frame(at: 0) else {
+                    return nil
+                }
+                image = KFCrossPlatformImage(cgImage: firstFrame, scale: options.scale, orientation: .up)
+            }
+            var kf = image?.kf
+            kf?.frameSource = source
+            kf?.animatedImageData = source.data
+        }
+        
+        image?.kf.imageFrameCount = source.frameCount
+        return image
+        #endif
+    }
+
+    /// Creates an image from a given data and options. `.JPEG`, `.PNG` or `.GIF` is supported. For other
+    /// image format, image initializer from system will be used. If no image object could be created from
+    /// the given `data`, `nil` will be returned.
+    ///
+    /// - Parameters:
+    ///   - data: The image data representation.
+    ///   - options: Options to use when creating the image.
+    /// - Returns: An `Image` object represents the image if created. If the `data` is invalid or not supported, `nil`
+    ///            will be returned.
+    public static func image(data: Data, options: ImageCreatingOptions) -> KFCrossPlatformImage? {
+        var image: KFCrossPlatformImage?
+        switch data.kf.imageFormat {
+        case .JPEG:
+            image = KFCrossPlatformImage(data: data, scale: options.scale)
+        case .PNG:
+            image = KFCrossPlatformImage(data: data, scale: options.scale)
+        case .GIF:
+            image = KingfisherWrapper.animatedImage(data: data, options: options)
+        case .unknown:
+            image = KFCrossPlatformImage(data: data, scale: options.scale)
+        }
+        return image
+    }
+    
+    /// Creates a downsampled image from given data to a certain size and scale.
+    ///
+    /// - Parameters:
+    ///   - data: The image data contains a JPEG or PNG image.
+    ///   - pointSize: The target size in point to which the image should be downsampled.
+    ///   - scale: The scale of result image.
+    /// - Returns: A downsampled `Image` object following the input conditions.
+    ///
+    /// - Note:
+    /// Different from image `resize` methods, downsampling will not render the original
+    /// input image in pixel format. It does downsampling from the image data, so it is much
+    /// more memory efficient and friendly. Choose to use downsampling as possible as you can.
+    ///
+    /// The pointsize should be smaller than the size of input image. If it is larger than the
+    /// original image size, the result image will be the same size of input without downsampling.
+    public static func downsampledImage(data: Data, to pointSize: CGSize, scale: CGFloat) -> KFCrossPlatformImage? {
+        let imageSourceOptions = [kCGImageSourceShouldCache: false] as CFDictionary
+        guard let imageSource = CGImageSourceCreateWithData(data as CFData, imageSourceOptions) else {
+            return nil
+        }
+        
+        let maxDimensionInPixels = max(pointSize.width, pointSize.height) * scale
+        let downsampleOptions: [CFString : Any] = [
+            kCGImageSourceCreateThumbnailFromImageAlways: true,
+            kCGImageSourceShouldCacheImmediately: true,
+            kCGImageSourceCreateThumbnailWithTransform: true,
+            kCGImageSourceThumbnailMaxPixelSize: maxDimensionInPixels
+        ]
+        guard let downsampledImage = CGImageSourceCreateThumbnailAtIndex(imageSource, 0, downsampleOptions as CFDictionary) else {
+            return nil
+        }
+        return KingfisherWrapper.image(cgImage: downsampledImage, scale: scale, refImage: nil)
+    }
+}

Pods/Kingfisher/Sources/Image/ImageDrawing.swift

@@ -0,0 +1,636 @@
+//
+//  ImageDrawing.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2018/09/28.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Accelerate
+
+#if canImport(AppKit) && !targetEnvironment(macCatalyst)
+import AppKit
+#endif
+#if canImport(UIKit)
+import UIKit
+#endif
+
+// MARK: - Image Transforming
+extension KingfisherWrapper where Base: KFCrossPlatformImage {
+    // MARK: Blend Mode
+    /// Create image from `base` image and apply blend mode.
+    ///
+    /// - parameter blendMode:       The blend mode of creating image.
+    /// - parameter alpha:           The alpha should be used for image.
+    /// - parameter backgroundColor: The background color for the output image.
+    ///
+    /// - returns: An image with blend mode applied.
+    ///
+    /// - Note: This method only works for CG-based image.
+    #if !os(macOS)
+    public func image(withBlendMode blendMode: CGBlendMode,
+                      alpha: CGFloat = 1.0,
+                      backgroundColor: KFCrossPlatformColor? = nil) -> KFCrossPlatformImage
+    {
+        guard let _ = cgImage else {
+            assertionFailure("[Kingfisher] Blend mode image only works for CG-based image.")
+            return base
+        }
+        
+        let rect = CGRect(origin: .zero, size: size)
+        return draw(to: rect.size, inverting: false) { _ in
+            if let backgroundColor = backgroundColor {
+                backgroundColor.setFill()
+                UIRectFill(rect)
+            }
+            
+            base.draw(in: rect, blendMode: blendMode, alpha: alpha)
+            return false
+        }
+    }
+    #endif
+    
+    #if os(macOS)
+    // MARK: Compositing
+    /// Creates image from `base` image and apply compositing operation.
+    ///
+    /// - Parameters:
+    ///   - compositingOperation: The compositing operation of creating image.
+    ///   - alpha: The alpha should be used for image.
+    ///   - backgroundColor: The background color for the output image.
+    /// - Returns: An image with compositing operation applied.
+    ///
+    /// - Note: This method only works for CG-based image. For any non-CG-based image, `base` itself is returned.
+    public func image(withCompositingOperation compositingOperation: NSCompositingOperation,
+                      alpha: CGFloat = 1.0,
+                      backgroundColor: KFCrossPlatformColor? = nil) -> KFCrossPlatformImage
+    {
+        guard let _ = cgImage else {
+            assertionFailure("[Kingfisher] Compositing Operation image only works for CG-based image.")
+            return base
+        }
+        
+        let rect = CGRect(origin: .zero, size: size)
+        return draw(to: rect.size, inverting: false) { _ in
+            if let backgroundColor = backgroundColor {
+                backgroundColor.setFill()
+                rect.fill()
+            }
+            base.draw(in: rect, from: .zero, operation: compositingOperation, fraction: alpha)
+            return false
+        }
+    }
+    #endif
+    
+    // MARK: Round Corner
+    
+    /// Creates a round corner image from on `base` image.
+    ///
+    /// - Parameters:
+    ///   - radius: The round corner radius of creating image.
+    ///   - size: The target size of creating image.
+    ///   - corners: The target corners which will be applied rounding.
+    ///   - backgroundColor: The background color for the output image
+    /// - Returns: An image with round corner of `self`.
+    ///
+    /// - Note: This method only works for CG-based image. The current image scale is kept.
+    ///         For any non-CG-based image, `base` itself is returned.
+    public func image(
+        withRadius radius: Radius,
+        fit size: CGSize,
+        roundingCorners corners: RectCorner = .all,
+        backgroundColor: KFCrossPlatformColor? = nil
+    ) -> KFCrossPlatformImage
+    {
+
+        guard let _ = cgImage else {
+            assertionFailure("[Kingfisher] Round corner image only works for CG-based image.")
+            return base
+        }
+        
+        let rect = CGRect(origin: CGPoint(x: 0, y: 0), size: size)
+        return draw(to: size, inverting: false) { _ in
+            #if os(macOS)
+            if let backgroundColor = backgroundColor {
+                let rectPath = NSBezierPath(rect: rect)
+                backgroundColor.setFill()
+                rectPath.fill()
+            }
+            
+            let path = pathForRoundCorner(rect: rect, radius: radius, corners: corners)
+            path.addClip()
+            base.draw(in: rect)
+            #else
+            guard let context = UIGraphicsGetCurrentContext() else {
+                assertionFailure("[Kingfisher] Failed to create CG context for image.")
+                return false
+            }
+            
+            if let backgroundColor = backgroundColor {
+                let rectPath = UIBezierPath(rect: rect)
+                backgroundColor.setFill()
+                rectPath.fill()
+            }
+            
+            let path = pathForRoundCorner(rect: rect, radius: radius, corners: corners)
+            context.addPath(path.cgPath)
+            context.clip()
+            base.draw(in: rect)
+            #endif
+            return false
+        }
+    }
+    
+    /// Creates a round corner image from on `base` image.
+    ///
+    /// - Parameters:
+    ///   - radius: The round corner radius of creating image.
+    ///   - size: The target size of creating image.
+    ///   - corners: The target corners which will be applied rounding.
+    ///   - backgroundColor: The background color for the output image
+    /// - Returns: An image with round corner of `self`.
+    ///
+    /// - Note: This method only works for CG-based image. The current image scale is kept.
+    ///         For any non-CG-based image, `base` itself is returned.
+    public func image(
+        withRoundRadius radius: CGFloat,
+        fit size: CGSize,
+        roundingCorners corners: RectCorner = .all,
+        backgroundColor: KFCrossPlatformColor? = nil
+    ) -> KFCrossPlatformImage
+    {
+        image(withRadius: .point(radius), fit: size, roundingCorners: corners, backgroundColor: backgroundColor)
+    }
+    
+    #if os(macOS)
+    func pathForRoundCorner(rect: CGRect, radius: Radius, corners: RectCorner, offsetBase: CGFloat = 0) -> NSBezierPath {
+        let cornerRadius = radius.compute(with: rect.size)
+        let path = NSBezierPath(roundedRect: rect, byRoundingCorners: corners, radius: cornerRadius - offsetBase / 2)
+        path.windingRule = .evenOdd
+        return path
+    }
+    #else
+    func pathForRoundCorner(rect: CGRect, radius: Radius, corners: RectCorner, offsetBase: CGFloat = 0) -> UIBezierPath {
+        let cornerRadius = radius.compute(with: rect.size)
+        return UIBezierPath(
+            roundedRect: rect,
+            byRoundingCorners: corners.uiRectCorner,
+            cornerRadii: CGSize(
+                width: cornerRadius - offsetBase / 2,
+                height: cornerRadius - offsetBase / 2
+            )
+        )
+    }
+    #endif
+    
+    #if os(iOS) || os(tvOS) || os(visionOS)
+    func resize(to size: CGSize, for contentMode: UIView.ContentMode) -> KFCrossPlatformImage {
+        switch contentMode {
+        case .scaleAspectFit:
+            return resize(to: size, for: .aspectFit)
+        case .scaleAspectFill:
+            return resize(to: size, for: .aspectFill)
+        default:
+            return resize(to: size)
+        }
+    }
+    #endif
+    
+    // MARK: Resizing
+    /// Resizes `base` image to an image with new size.
+    ///
+    /// - Parameter size: The target size in point.
+    /// - Returns: An image with new size.
+    /// - Note: This method only works for CG-based image. The current image scale is kept.
+    ///         For any non-CG-based image, `base` itself is returned.
+    public func resize(to size: CGSize) -> KFCrossPlatformImage {
+        guard let _ = cgImage else {
+            assertionFailure("[Kingfisher] Resize only works for CG-based image.")
+            return base
+        }
+        
+        let rect = CGRect(origin: CGPoint(x: 0, y: 0), size: size)
+        return draw(to: size, inverting: false) { _ in
+            #if os(macOS)
+            base.draw(in: rect, from: .zero, operation: .copy, fraction: 1.0)
+            #else
+            base.draw(in: rect)
+            #endif
+            return false
+        }
+    }
+    
+    /// Resizes `base` image to an image of new size, respecting the given content mode.
+    ///
+    /// - Parameters:
+    ///   - targetSize: The target size in point.
+    ///   - contentMode: Content mode of output image should be.
+    /// - Returns: An image with new size.
+    ///
+    /// - Note: This method only works for CG-based image. The current image scale is kept.
+    ///         For any non-CG-based image, `base` itself is returned.
+    public func resize(to targetSize: CGSize, for contentMode: ContentMode) -> KFCrossPlatformImage {
+        let newSize = size.kf.resize(to: targetSize, for: contentMode)
+        return resize(to: newSize)
+    }
+
+    // MARK: Cropping
+    /// Crops `base` image to a new size with a given anchor.
+    ///
+    /// - Parameters:
+    ///   - size: The target size.
+    ///   - anchor: The anchor point from which the size should be calculated.
+    /// - Returns: An image with new size.
+    ///
+    /// - Note: This method only works for CG-based image. The current image scale is kept.
+    ///         For any non-CG-based image, `base` itself is returned.
+    public func crop(to size: CGSize, anchorOn anchor: CGPoint) -> KFCrossPlatformImage {
+        guard let cgImage = cgImage else {
+            assertionFailure("[Kingfisher] Crop only works for CG-based image.")
+            return base
+        }
+        
+        let rect = self.size.kf.constrainedRect(for: size, anchor: anchor)
+        guard let image = cgImage.cropping(to: rect.scaled(scale)) else {
+            assertionFailure("[Kingfisher] Cropping image failed.")
+            return base
+        }
+        
+        return KingfisherWrapper.image(cgImage: image, scale: scale, refImage: base)
+    }
+    
+    // MARK: Blur
+    /// Creates an image with blur effect based on `base` image.
+    ///
+    /// - Parameter radius: The blur radius should be used when creating blur effect.
+    /// - Returns: An image with blur effect applied.
+    ///
+    /// - Note: This method only works for CG-based image. The current image scale is kept.
+    ///         For any non-CG-based image, `base` itself is returned.
+    public func blurred(withRadius radius: CGFloat) -> KFCrossPlatformImage {
+        
+        guard let cgImage = cgImage else {
+            assertionFailure("[Kingfisher] Blur only works for CG-based image.")
+            return base
+        }
+        
+        // http://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement
+        // let d = floor(s * 3*sqrt(2*pi)/4 + 0.5)
+        // if d is odd, use three box-blurs of size 'd', centered on the output pixel.
+        let s = max(radius, 2.0)
+        // We will do blur on a resized image (*0.5), so the blur radius could be half as well.
+        
+        // Fix the slow compiling time for Swift 3.
+        // See https://github.com/onevcat/Kingfisher/issues/611
+        let pi2 = 2 * CGFloat.pi
+        let sqrtPi2 = sqrt(pi2)
+        var targetRadius = floor(s * 3.0 * sqrtPi2 / 4.0 + 0.5)
+        
+        if targetRadius.isEven { targetRadius += 1 }
+
+        // Determine necessary iteration count by blur radius.
+        let iterations: Int
+        if radius < 0.5 {
+            iterations = 1
+        } else if radius < 1.5 {
+            iterations = 2
+        } else {
+            iterations = 3
+        }
+        
+        let w = Int(size.width)
+        let h = Int(size.height)
+        
+        func createEffectBuffer(_ context: CGContext) -> vImage_Buffer {
+            let data = context.data
+            let width = vImagePixelCount(context.width)
+            let height = vImagePixelCount(context.height)
+            let rowBytes = context.bytesPerRow
+            
+            return vImage_Buffer(data: data, height: height, width: width, rowBytes: rowBytes)
+        }
+        GraphicsContext.begin(size: size, scale: scale)
+        guard let context = GraphicsContext.current(size: size, scale: scale, inverting: true, cgImage: cgImage) else {
+            assertionFailure("[Kingfisher] Failed to create CG context for blurring image.")
+            return base
+        }
+        context.draw(cgImage, in: CGRect(x: 0, y: 0, width: w, height: h))
+        GraphicsContext.end()
+        
+        var inBuffer = createEffectBuffer(context)
+        
+        GraphicsContext.begin(size: size, scale: scale)
+        guard let outContext = GraphicsContext.current(size: size, scale: scale, inverting: true, cgImage: cgImage) else {
+            assertionFailure("[Kingfisher] Failed to create CG context for blurring image.")
+            return base
+        }
+        defer { GraphicsContext.end() }
+        var outBuffer = createEffectBuffer(outContext)
+        
+        for _ in 0 ..< iterations {
+            let flag = vImage_Flags(kvImageEdgeExtend)
+            vImageBoxConvolve_ARGB8888(
+                &inBuffer, &outBuffer, nil, 0, 0, UInt32(targetRadius), UInt32(targetRadius), nil, flag)
+            // Next inBuffer should be the outButter of current iteration
+            (inBuffer, outBuffer) = (outBuffer, inBuffer)
+        }
+        
+        #if os(macOS)
+        let result = outContext.makeImage().flatMap {
+            fixedForRetinaPixel(cgImage: $0, to: size)
+        }
+        #else
+        let result = outContext.makeImage().flatMap {
+            KFCrossPlatformImage(cgImage: $0, scale: base.scale, orientation: base.imageOrientation)
+        }
+        #endif
+        guard let blurredImage = result else {
+            assertionFailure("[Kingfisher] Can not make an blurred image within this context.")
+            return base
+        }
+        
+        return blurredImage
+    }
+    
+    public func addingBorder(_ border: Border) -> KFCrossPlatformImage
+    {
+        guard let _ = cgImage else {
+            assertionFailure("[Kingfisher] Blend mode image only works for CG-based image.")
+            return base
+        }
+        
+        let rect = CGRect(origin: .zero, size: size)
+        return draw(to: rect.size, inverting: false) { context in
+            
+            #if os(macOS)
+            base.draw(in: rect)
+            #else
+            base.draw(in: rect, blendMode: .normal, alpha: 1.0)
+            #endif
+            
+            
+            let strokeRect =  rect.insetBy(dx: border.lineWidth / 2, dy: border.lineWidth / 2)
+            context.setStrokeColor(border.color.cgColor)
+            context.setAlpha(border.color.rgba.a)
+            
+            let line = pathForRoundCorner(
+                rect: strokeRect,
+                radius: border.radius,
+                corners: border.roundingCorners,
+                offsetBase: border.lineWidth
+            )
+            line.lineCapStyle = .square
+            line.lineWidth = border.lineWidth
+            line.stroke()
+            
+            return false
+        }
+    }
+    
+    // MARK: Overlay
+    /// Creates an image from `base` image with a color overlay layer.
+    ///
+    /// - Parameters:
+    ///   - color: The color should be use to overlay.
+    ///   - fraction: Fraction of input color. From 0.0 to 1.0. 0.0 means solid color,
+    ///               1.0 means transparent overlay.
+    /// - Returns: An image with a color overlay applied.
+    ///
+    /// - Note: This method only works for CG-based image. The current image scale is kept.
+    ///         For any non-CG-based image, `base` itself is returned.
+    public func overlaying(with color: KFCrossPlatformColor, fraction: CGFloat) -> KFCrossPlatformImage {
+        
+        guard let _ = cgImage else {
+            assertionFailure("[Kingfisher] Overlaying only works for CG-based image.")
+            return base
+        }
+        
+        let rect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
+        return draw(to: rect.size, inverting: false) { context in
+            #if os(macOS)
+            base.draw(in: rect)
+            if fraction > 0 {
+                color.withAlphaComponent(1 - fraction).set()
+                rect.fill(using: .sourceAtop)
+            }
+            #else
+            color.set()
+            UIRectFill(rect)
+            base.draw(in: rect, blendMode: .destinationIn, alpha: 1.0)
+            
+            if fraction > 0 {
+                base.draw(in: rect, blendMode: .sourceAtop, alpha: fraction)
+            }
+            #endif
+            return false
+        }
+    }
+    
+    // MARK: Tint
+    /// Creates an image from `base` image with a color tint.
+    ///
+    /// - Parameter color: The color should be used to tint `base`
+    /// - Returns: An image with a color tint applied.
+    public func tinted(with color: KFCrossPlatformColor) -> KFCrossPlatformImage {
+        #if os(watchOS)
+        return base
+        #else
+        return apply(.tint(color))
+        #endif
+    }
+    
+    // MARK: Color Control
+    
+    /// Create an image from `self` with color control.
+    ///
+    /// - Parameters:
+    ///   - brightness: Brightness changing to image.
+    ///   - contrast: Contrast changing to image.
+    ///   - saturation: Saturation changing to image.
+    ///   - inputEV: InputEV changing to image.
+    /// - Returns:  An image with color control applied.
+    public func adjusted(brightness: CGFloat, contrast: CGFloat, saturation: CGFloat, inputEV: CGFloat) -> KFCrossPlatformImage {
+        #if os(watchOS)
+        return base
+        #else
+        return apply(.colorControl((brightness, contrast, saturation, inputEV)))
+        #endif
+    }
+    
+    /// Return an image with given scale.
+    ///
+    /// - Parameter scale: Target scale factor the new image should have.
+    /// - Returns: The image with target scale. If the base image is already in the scale, `base` will be returned.
+    public func scaled(to scale: CGFloat) -> KFCrossPlatformImage {
+        guard scale != self.scale else {
+            return base
+        }
+        guard let cgImage = cgImage else {
+            assertionFailure("[Kingfisher] Scaling only works for CG-based image.")
+            return base
+        }
+        return KingfisherWrapper.image(cgImage: cgImage, scale: scale, refImage: base)
+    }
+}
+
+// MARK: - Decoding Image
+extension KingfisherWrapper where Base: KFCrossPlatformImage {
+    
+    /// Returns the decoded image of the `base` image. It will draw the image in a plain context and return the data
+    /// from it. This could improve the drawing performance when an image is just created from data but not yet
+    /// displayed for the first time.
+    ///
+    /// - Note: This method only works for CG-based image. The current image scale is kept.
+    ///         For any non-CG-based image or animated image, `base` itself is returned.
+    public var decoded: KFCrossPlatformImage { return decoded(scale: scale) }
+    
+    /// Returns decoded image of the `base` image at a given scale. It will draw the image in a plain context and
+    /// return the data from it. This could improve the drawing performance when an image is just created from
+    /// data but not yet displayed for the first time.
+    ///
+    /// - Parameter scale: The given scale of target image should be.
+    /// - Returns: The decoded image ready to be displayed.
+    ///
+    /// - Note: This method only works for CG-based image. The current image scale is kept.
+    ///         For any non-CG-based image or animated image, `base` itself is returned.
+    public func decoded(scale: CGFloat) -> KFCrossPlatformImage {
+        // Prevent animated image (GIF) losing it's images
+        #if os(iOS) || os(visionOS)
+        if frameSource != nil { return base }
+        #else
+        if images != nil { return base }
+        #endif
+
+        guard let imageRef = cgImage else {
+            assertionFailure("[Kingfisher] Decoding only works for CG-based image.")
+            return base
+        }
+
+        let size = CGSize(width: CGFloat(imageRef.width) / scale, height: CGFloat(imageRef.height) / scale)
+        return draw(to: size, inverting: true, scale: scale) { context in
+            context.draw(imageRef, in: CGRect(origin: .zero, size: size))
+            return true
+        }
+    }
+
+    /// Returns decoded image of the `base` image at a given scale. It will draw the image in a plain context and
+    /// return the data from it. This could improve the drawing performance when an image is just created from
+    /// data but not yet displayed for the first time.
+    ///
+    /// - Parameter context: The context for drawing.
+    /// - Returns: The decoded image ready to be displayed.
+    ///
+    /// - Note: This method only works for CG-based image. The current image scale is kept.
+    ///         For any non-CG-based image or animated image, `base` itself is returned.
+    public func decoded(on context: CGContext) -> KFCrossPlatformImage {
+        // Prevent animated image (GIF) losing it's images
+        #if os(iOS) || os(visionOS)
+        if frameSource != nil { return base }
+        #else
+        if images != nil { return base }
+        #endif
+
+        guard let refImage = cgImage,
+              let decodedRefImage = refImage.decoded(on: context, scale: scale) else
+        {
+            assertionFailure("[Kingfisher] Decoding only works for CG-based image.")
+            return base
+        }
+        return KingfisherWrapper.image(cgImage: decodedRefImage, scale: scale, refImage: base)
+    }
+}
+
+extension CGImage {
+    func decoded(on context: CGContext, scale: CGFloat) -> CGImage? {
+        let size = CGSize(width: CGFloat(self.width) / scale, height: CGFloat(self.height) / scale)
+        context.draw(self, in: CGRect(origin: .zero, size: size))
+        guard let decodedImageRef = context.makeImage() else {
+            return nil
+        }
+        return decodedImageRef
+    }
+}
+
+extension KingfisherWrapper where Base: KFCrossPlatformImage {
+    func draw(
+        to size: CGSize,
+        inverting: Bool,
+        scale: CGFloat? = nil,
+        refImage: KFCrossPlatformImage? = nil,
+        draw: (CGContext) -> Bool // Whether use the refImage (`true`) or ignore image orientation (`false`)
+    ) -> KFCrossPlatformImage
+    {
+        #if os(macOS) || os(watchOS)
+        let targetScale = scale ?? self.scale
+        GraphicsContext.begin(size: size, scale: targetScale)
+        guard let context = GraphicsContext.current(size: size, scale: targetScale, inverting: inverting, cgImage: cgImage) else {
+            assertionFailure("[Kingfisher] Failed to create CG context for blurring image.")
+            return base
+        }
+        defer { GraphicsContext.end() }
+        let useRefImage = draw(context)
+        guard let cgImage = context.makeImage() else {
+            return base
+        }
+        let ref = useRefImage ? (refImage ?? base) : nil
+        return KingfisherWrapper.image(cgImage: cgImage, scale: targetScale, refImage: ref)
+        #else
+        
+        let format = UIGraphicsImageRendererFormat.preferred()
+        format.scale = scale ?? self.scale
+        let renderer = UIGraphicsImageRenderer(size: size, format: format)
+        
+        var useRefImage: Bool = false
+        let image = renderer.image { rendererContext in
+            
+            let context = rendererContext.cgContext
+            if inverting { // If drawing a CGImage, we need to make context flipped.
+                context.scaleBy(x: 1.0, y: -1.0)
+                context.translateBy(x: 0, y: -size.height)
+            }
+            
+            useRefImage = draw(context)
+        }
+        if useRefImage {
+            guard let cgImage = image.cgImage else {
+                return base
+            }
+            let ref = refImage ?? base
+            return KingfisherWrapper.image(cgImage: cgImage, scale: format.scale, refImage: ref)
+        } else {
+            return image
+        }
+        #endif
+    }
+    
+    #if os(macOS)
+    func fixedForRetinaPixel(cgImage: CGImage, to size: CGSize) -> KFCrossPlatformImage {
+        
+        let image = KFCrossPlatformImage(cgImage: cgImage, size: base.size)
+        let rect = CGRect(origin: CGPoint(x: 0, y: 0), size: size)
+        
+        return draw(to: self.size, inverting: false) { context in
+            image.draw(in: rect, from: .zero, operation: .copy, fraction: 1.0)
+            return false
+        }
+    }
+    #endif
+}

Pods/Kingfisher/Sources/Image/ImageFormat.swift

@@ -0,0 +1,130 @@
+//
+//  ImageFormat.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2018/09/28.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+/// Represents image format.
+///
+/// - unknown: The format cannot be recognized or not supported yet.
+/// - PNG: PNG image format.
+/// - JPEG: JPEG image format.
+/// - GIF: GIF image format.
+public enum ImageFormat {
+    /// The format cannot be recognized or not supported yet.
+    case unknown
+    /// PNG image format.
+    case PNG
+    /// JPEG image format.
+    case JPEG
+    /// GIF image format.
+    case GIF
+    
+    struct HeaderData {
+        static var PNG: [UInt8] = [0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A]
+        static var JPEG_SOI: [UInt8] = [0xFF, 0xD8]
+        static var JPEG_IF: [UInt8] = [0xFF]
+        static var GIF: [UInt8] = [0x47, 0x49, 0x46]
+    }
+    
+    /// https://en.wikipedia.org/wiki/JPEG
+    public enum JPEGMarker {
+        case SOF0           //baseline
+        case SOF2           //progressive
+        case DHT            //Huffman Table
+        case DQT            //Quantization Table
+        case DRI            //Restart Interval
+        case SOS            //Start Of Scan
+        case RSTn(UInt8)    //Restart
+        case APPn           //Application-specific
+        case COM            //Comment
+        case EOI            //End Of Image
+        
+        var bytes: [UInt8] {
+            switch self {
+            case .SOF0:         return [0xFF, 0xC0]
+            case .SOF2:         return [0xFF, 0xC2]
+            case .DHT:          return [0xFF, 0xC4]
+            case .DQT:          return [0xFF, 0xDB]
+            case .DRI:          return [0xFF, 0xDD]
+            case .SOS:          return [0xFF, 0xDA]
+            case .RSTn(let n):  return [0xFF, 0xD0 + n]
+            case .APPn:         return [0xFF, 0xE0]
+            case .COM:          return [0xFF, 0xFE]
+            case .EOI:          return [0xFF, 0xD9]
+            }
+        }
+    }
+}
+
+
+extension Data: KingfisherCompatibleValue {}
+
+// MARK: - Misc Helpers
+extension KingfisherWrapper where Base == Data {
+    /// Gets the image format corresponding to the data.
+    public var imageFormat: ImageFormat {
+        guard base.count > 8 else { return .unknown }
+        
+        var buffer = [UInt8](repeating: 0, count: 8)
+        base.copyBytes(to: &buffer, count: 8)
+        
+        if buffer == ImageFormat.HeaderData.PNG {
+            return .PNG
+            
+        } else if buffer[0] == ImageFormat.HeaderData.JPEG_SOI[0],
+            buffer[1] == ImageFormat.HeaderData.JPEG_SOI[1],
+            buffer[2] == ImageFormat.HeaderData.JPEG_IF[0]
+        {
+            return .JPEG
+            
+        } else if buffer[0] == ImageFormat.HeaderData.GIF[0],
+            buffer[1] == ImageFormat.HeaderData.GIF[1],
+            buffer[2] == ImageFormat.HeaderData.GIF[2]
+        {
+            return .GIF
+        }
+        
+        return .unknown
+    }
+    
+    public func contains(jpeg marker: ImageFormat.JPEGMarker) -> Bool {
+        guard imageFormat == .JPEG else {
+            return false
+        }
+        
+        let bytes = [UInt8](base)
+        let markerBytes = marker.bytes
+        for (index, item) in bytes.enumerated() where bytes.count > index + 1 {
+            guard
+                item == markerBytes.first,
+                bytes[index + 1] == markerBytes[1] else {
+                continue
+            }
+            return true
+        }
+        return false
+    }
+}

Pods/Kingfisher/Sources/Image/ImageProcessor.swift

@@ -0,0 +1,922 @@
+//
+//  ImageProcessor.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2016/08/26.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+import CoreGraphics
+
+#if canImport(AppKit) && !targetEnvironment(macCatalyst)
+import AppKit
+#else
+import UIKit
+#endif
+
+/// Represents an item which could be processed by an `ImageProcessor`.
+///
+/// - image: Input image. The processor should provide a way to apply
+///          processing on this `image` and return the result image.
+/// - data:  Input data. The processor should provide a way to apply
+///          processing on this `data` and return the result image.
+public enum ImageProcessItem {
+    
+    /// Input image. The processor should provide a way to apply
+    /// processing on this `image` and return the result image.
+    case image(KFCrossPlatformImage)
+    
+    /// Input data. The processor should provide a way to apply
+    /// processing on this `data` and return the result image.
+    case data(Data)
+}
+
+/// An `ImageProcessor` would be used to convert some downloaded data to an image.
+public protocol ImageProcessor {
+    /// Identifier of the processor. It will be used to identify the processor when 
+    /// caching and retrieving an image. You might want to make sure that processors with
+    /// same properties/functionality have the same identifiers, so correct processed images
+    /// could be retrieved with proper key.
+    /// 
+    /// - Note: Do not supply an empty string for a customized processor, which is already reserved by
+    /// the `DefaultImageProcessor`. It is recommended to use a reverse domain name notation string of
+    /// your own for the identifier.
+    var identifier: String { get }
+
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: The parsed options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: The return value should be `nil` if processing failed while converting an input item to image.
+    ///         If `nil` received by the processing caller, an error will be reported and the process flow stops.
+    ///         If the processing flow is not critical for your flow, then when the input item is already an image
+    ///         (`.image` case) and there is any errors in the processing, you could return the input image itself
+    ///         to keep the processing pipeline continuing.
+    /// - Note: Most processor only supports CG-based images. watchOS is not supported for processors containing
+    ///         a filter, the input image will be returned directly on watchOS.
+    func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage?
+}
+
+extension ImageProcessor {
+    
+    /// Appends an `ImageProcessor` to another. The identifier of the new `ImageProcessor`
+    /// will be "\(self.identifier)|>\(another.identifier)".
+    ///
+    /// - Parameter another: An `ImageProcessor` you want to append to `self`.
+    /// - Returns: The new `ImageProcessor` will process the image in the order
+    ///            of the two processors concatenated.
+    public func append(another: ImageProcessor) -> ImageProcessor {
+        let newIdentifier = identifier.appending("|>\(another.identifier)")
+        return GeneralProcessor(identifier: newIdentifier) {
+            item, options in
+            if let image = self.process(item: item, options: options) {
+                return another.process(item: .image(image), options: options)
+            } else {
+                return nil
+            }
+        }
+    }
+}
+
+func ==(left: ImageProcessor, right: ImageProcessor) -> Bool {
+    return left.identifier == right.identifier
+}
+
+func !=(left: ImageProcessor, right: ImageProcessor) -> Bool {
+    return !(left == right)
+}
+
+typealias ProcessorImp = ((ImageProcessItem, KingfisherParsedOptionsInfo) -> KFCrossPlatformImage?)
+struct GeneralProcessor: ImageProcessor {
+    let identifier: String
+    let p: ProcessorImp
+    func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        return p(item, options)
+    }
+}
+
+/// The default processor. It converts the input data to a valid image.
+/// Images of .PNG, .JPEG and .GIF format are supported.
+/// If an image item is given as `.image` case, `DefaultImageProcessor` will
+/// do nothing on it and return the associated image.
+public struct DefaultImageProcessor: ImageProcessor {
+    
+    /// A default `DefaultImageProcessor` could be used across.
+    public static let `default` = DefaultImageProcessor()
+    
+    /// Identifier of the processor.
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public let identifier = ""
+    
+    /// Creates a `DefaultImageProcessor`. Use `DefaultImageProcessor.default` to get an instance,
+    /// if you do not have a good reason to create your own `DefaultImageProcessor`.
+    public init() {}
+    
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            return image.kf.scaled(to: options.scaleFactor)
+        case .data(let data):
+            return KingfisherWrapper.image(data: data, options: options.imageCreatingOptions)
+        }
+    }
+}
+
+/// Represents the rect corner setting when processing a round corner image.
+public struct RectCorner: OptionSet {
+    
+    /// Raw value of the rect corner.
+    public let rawValue: Int
+    
+    /// Represents the top left corner.
+    public static let topLeft = RectCorner(rawValue: 1 << 0)
+    
+    /// Represents the top right corner.
+    public static let topRight = RectCorner(rawValue: 1 << 1)
+    
+    /// Represents the bottom left corner.
+    public static let bottomLeft = RectCorner(rawValue: 1 << 2)
+    
+    /// Represents the bottom right corner.
+    public static let bottomRight = RectCorner(rawValue: 1 << 3)
+    
+    /// Represents all corners.
+    public static let all: RectCorner = [.topLeft, .topRight, .bottomLeft, .bottomRight]
+    
+    /// Creates a `RectCorner` option set with a given value.
+    ///
+    /// - Parameter rawValue: The value represents a certain corner option.
+    public init(rawValue: Int) {
+        self.rawValue = rawValue
+    }
+    
+    var cornerIdentifier: String {
+        if self == .all {
+            return ""
+        }
+        return "_corner(\(rawValue))"
+    }
+}
+
+#if !os(macOS)
+/// Processor for adding an blend mode to images. Only CG-based images are supported.
+public struct BlendImageProcessor: ImageProcessor {
+
+    /// Identifier of the processor.
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public let identifier: String
+
+    /// Blend Mode will be used to blend the input image.
+    public let blendMode: CGBlendMode
+
+    /// Alpha will be used when blend image.
+    public let alpha: CGFloat
+
+    /// Background color of the output image. If `nil`, it will stay transparent.
+    public let backgroundColor: KFCrossPlatformColor?
+
+    /// Creates a `BlendImageProcessor`.
+    ///
+    /// - Parameters:
+    ///   - blendMode: Blend Mode will be used to blend the input image.
+    ///   - alpha: Alpha will be used when blend image. From 0.0 to 1.0. 1.0 means solid image,
+    ///            0.0 means transparent image (not visible at all). Default is 1.0.
+    ///   - backgroundColor: Background color to apply for the output image. Default is `nil`.
+    public init(blendMode: CGBlendMode, alpha: CGFloat = 1.0, backgroundColor: KFCrossPlatformColor? = nil) {
+        self.blendMode = blendMode
+        self.alpha = alpha
+        self.backgroundColor = backgroundColor
+        var identifier = "com.onevcat.Kingfisher.BlendImageProcessor(\(blendMode.rawValue),\(alpha))"
+        if let color = backgroundColor {
+            identifier.append("_\(color.rgbaDescription)")
+        }
+        self.identifier = identifier
+    }
+
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            return image.kf.scaled(to: options.scaleFactor)
+                        .kf.image(withBlendMode: blendMode, alpha: alpha, backgroundColor: backgroundColor)
+        case .data:
+            return (DefaultImageProcessor.default |> self).process(item: item, options: options)
+        }
+    }
+}
+#endif
+
+#if os(macOS)
+/// Processor for adding an compositing operation to images. Only CG-based images are supported in macOS.
+public struct CompositingImageProcessor: ImageProcessor {
+
+    /// Identifier of the processor.
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public let identifier: String
+
+    /// Compositing operation will be used to the input image.
+    public let compositingOperation: NSCompositingOperation
+
+    /// Alpha will be used when compositing image.
+    public let alpha: CGFloat
+
+    /// Background color of the output image. If `nil`, it will stay transparent.
+    public let backgroundColor: KFCrossPlatformColor?
+
+    /// Creates a `CompositingImageProcessor`
+    ///
+    /// - Parameters:
+    ///   - compositingOperation: Compositing operation will be used to the input image.
+    ///   - alpha: Alpha will be used when compositing image.
+    ///            From 0.0 to 1.0. 1.0 means solid image, 0.0 means transparent image.
+    ///            Default is 1.0.
+    ///   - backgroundColor: Background color to apply for the output image. Default is `nil`.
+    public init(compositingOperation: NSCompositingOperation,
+                alpha: CGFloat = 1.0,
+                backgroundColor: KFCrossPlatformColor? = nil)
+    {
+        self.compositingOperation = compositingOperation
+        self.alpha = alpha
+        self.backgroundColor = backgroundColor
+        var identifier = "com.onevcat.Kingfisher.CompositingImageProcessor(\(compositingOperation.rawValue),\(alpha))"
+        if let color = backgroundColor {
+            identifier.append("_\(color.rgbaDescription)")
+        }
+        self.identifier = identifier
+    }
+
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            return image.kf.scaled(to: options.scaleFactor)
+                        .kf.image(
+                            withCompositingOperation: compositingOperation,
+                            alpha: alpha,
+                            backgroundColor: backgroundColor)
+        case .data:
+            return (DefaultImageProcessor.default |> self).process(item: item, options: options)
+        }
+    }
+}
+#endif
+
+/// Represents a radius specified in a `RoundCornerImageProcessor`.
+public enum Radius {
+    /// The radius should be calculated as a fraction of the image width. Typically the associated value should be
+    /// between 0 and 0.5, where 0 represents no radius and 0.5 represents using half of the image width.
+    case widthFraction(CGFloat)
+    /// The radius should be calculated as a fraction of the image height. Typically the associated value should be
+    /// between 0 and 0.5, where 0 represents no radius and 0.5 represents using half of the image height.
+    case heightFraction(CGFloat)
+    /// Use a fixed point value as the round corner radius.
+    case point(CGFloat)
+
+    var radiusIdentifier: String {
+        switch self {
+        case .widthFraction(let f):
+            return "w_frac_\(f)"
+        case .heightFraction(let f):
+            return "h_frac_\(f)"
+        case .point(let p):
+            return p.description
+        }
+    }
+    
+    public func compute(with size: CGSize) -> CGFloat {
+        let cornerRadius: CGFloat
+        switch self {
+        case .point(let point):
+            cornerRadius = point
+        case .widthFraction(let widthFraction):
+            cornerRadius = size.width * widthFraction
+        case .heightFraction(let heightFraction):
+            cornerRadius = size.height * heightFraction
+        }
+        return cornerRadius
+    }
+}
+
+/// Processor for making round corner images. Only CG-based images are supported in macOS, 
+/// if a non-CG image passed in, the processor will do nothing.
+///
+/// - Note: The input image will be rendered with round corner pixels removed. If the image itself does not contain
+/// alpha channel (for example, a JPEG image), the processed image will contain an alpha channel in memory in order
+/// to show correctly. However, when cached to disk, Kingfisher respects the original image format by default. That
+/// means the alpha channel will be removed for these images. When you load the processed image from cache again, you
+/// will lose transparent corner.
+///
+/// You could use `FormatIndicatedCacheSerializer.png` to force Kingfisher to serialize the image to PNG format in this
+/// case.
+///
+public struct RoundCornerImageProcessor: ImageProcessor {
+
+    /// Identifier of the processor.
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public let identifier: String
+
+    /// The radius will be applied in processing. Specify a certain point value with `.point`, or a fraction of the
+    /// target image with `.widthFraction`. or `.heightFraction`. For example, given a square image with width and
+    /// height equals,  `.widthFraction(0.5)` means use half of the length of size and makes the final image a round one.
+    public let radius: Radius
+    
+    /// The target corners which will be applied rounding.
+    public let roundingCorners: RectCorner
+    
+    /// Target size of output image should be. If `nil`, the image will keep its original size after processing.
+    public let targetSize: CGSize?
+
+    /// Background color of the output image. If `nil`, it will use a transparent background.
+    public let backgroundColor: KFCrossPlatformColor?
+
+    /// Creates a `RoundCornerImageProcessor`.
+    ///
+    /// - Parameters:
+    ///   - cornerRadius: Corner radius in point will be applied in processing.
+    ///   - targetSize: Target size of output image should be. If `nil`,
+    ///                 the image will keep its original size after processing.
+    ///                 Default is `nil`.
+    ///   - corners: The target corners which will be applied rounding. Default is `.all`.
+    ///   - backgroundColor: Background color to apply for the output image. Default is `nil`.
+    ///
+    /// - Note:
+    ///
+    /// This initializer accepts a concrete point value for `cornerRadius`. If you do not know the image size, but still
+    /// want to apply a full round-corner (making the final image a round one), or specify the corner radius as a
+    /// fraction of one dimension of the target image, use the `Radius` version instead.
+    ///
+    public init(
+        cornerRadius: CGFloat,
+        targetSize: CGSize? = nil,
+        roundingCorners corners: RectCorner = .all,
+        backgroundColor: KFCrossPlatformColor? = nil
+    )
+    {
+        let radius = Radius.point(cornerRadius)
+        self.init(radius: radius, targetSize: targetSize, roundingCorners: corners, backgroundColor: backgroundColor)
+    }
+
+    /// Creates a `RoundCornerImageProcessor`.
+    ///
+    /// - Parameters:
+    ///   - radius: The radius will be applied in processing.
+    ///   - targetSize: Target size of output image should be. If `nil`,
+    ///                 the image will keep its original size after processing.
+    ///                 Default is `nil`.
+    ///   - corners: The target corners which will be applied rounding. Default is `.all`.
+    ///   - backgroundColor: Background color to apply for the output image. Default is `nil`.
+    public init(
+        radius: Radius,
+        targetSize: CGSize? = nil,
+        roundingCorners corners: RectCorner = .all,
+        backgroundColor: KFCrossPlatformColor? = nil
+    )
+    {
+        self.radius = radius
+        self.targetSize = targetSize
+        self.roundingCorners = corners
+        self.backgroundColor = backgroundColor
+
+        self.identifier = {
+            var identifier = ""
+
+            if let size = targetSize {
+                identifier = "com.onevcat.Kingfisher.RoundCornerImageProcessor" +
+                             "(\(radius.radiusIdentifier)_\(size)\(corners.cornerIdentifier))"
+            } else {
+                identifier = "com.onevcat.Kingfisher.RoundCornerImageProcessor" +
+                             "(\(radius.radiusIdentifier)\(corners.cornerIdentifier))"
+            }
+            if let backgroundColor = backgroundColor {
+                identifier += "_\(backgroundColor)"
+            }
+
+            return identifier
+        }()
+    }
+    
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            let size = targetSize ?? image.kf.size
+            return image.kf.scaled(to: options.scaleFactor)
+                        .kf.image(
+                            withRadius: radius,
+                            fit: size,
+                            roundingCorners: roundingCorners,
+                            backgroundColor: backgroundColor)
+        case .data:
+            return (DefaultImageProcessor.default |> self).process(item: item, options: options)
+        }
+    }
+}
+
+public struct Border {
+    public var color: KFCrossPlatformColor
+    public var lineWidth: CGFloat
+    
+    /// The radius will be applied in processing. Specify a certain point value with `.point`, or a fraction of the
+    /// target image with `.widthFraction`. or `.heightFraction`. For example, given a square image with width and
+    /// height equals,  `.widthFraction(0.5)` means use half of the length of size and makes the final image a round one.
+    public var radius: Radius
+    
+    /// The target corners which will be applied rounding.
+    public var roundingCorners: RectCorner
+    
+    public init(
+        color: KFCrossPlatformColor = .black,
+        lineWidth: CGFloat = 4,
+        radius: Radius = .point(0),
+        roundingCorners: RectCorner = .all
+    ) {
+        self.color = color
+        self.lineWidth = lineWidth
+        self.radius = radius
+        self.roundingCorners = roundingCorners
+    }
+    
+    var identifier: String {
+        "\(color.rgbaDescription)_\(lineWidth)_\(radius.radiusIdentifier)_\(roundingCorners.cornerIdentifier)"
+    }
+}
+
+public struct BorderImageProcessor: ImageProcessor {
+    public var identifier: String { "com.onevcat.Kingfisher.RoundCornerImageProcessor(\(border)" }
+    public let border: Border
+    
+    public init(border: Border) {
+        self.border = border
+    }
+    
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            return image.kf.addingBorder(border)
+        case .data:
+            return (DefaultImageProcessor.default |> self).process(item: item, options: options)
+        }
+    }
+}
+
+/// Represents how a size adjusts itself to fit a target size.
+///
+/// - none: Not scale the content.
+/// - aspectFit: Scales the content to fit the size of the view by maintaining the aspect ratio.
+/// - aspectFill: Scales the content to fill the size of the view.
+public enum ContentMode {
+    /// Not scale the content.
+    case none
+    /// Scales the content to fit the size of the view by maintaining the aspect ratio.
+    case aspectFit
+    /// Scales the content to fill the size of the view.
+    case aspectFill
+}
+
+/// Processor for resizing images.
+/// If you need to resize a data represented image to a smaller size, use `DownsamplingImageProcessor`
+/// instead, which is more efficient and uses less memory.
+public struct ResizingImageProcessor: ImageProcessor {
+    
+    /// Identifier of the processor.
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public let identifier: String
+    
+    /// The reference size for resizing operation in point.
+    public let referenceSize: CGSize
+    
+    /// Target content mode of output image should be.
+    /// Default is `.none`.
+    public let targetContentMode: ContentMode
+    
+    /// Creates a `ResizingImageProcessor`.
+    ///
+    /// - Parameters:
+    ///   - referenceSize: The reference size for resizing operation in point.
+    ///   - mode: Target content mode of output image should be.
+    ///
+    /// - Note:
+    ///   The instance of `ResizingImageProcessor` will follow its `mode` property
+    ///   and try to resizing the input images to fit or fill the `referenceSize`.
+    ///   That means if you are using a `mode` besides of `.none`, you may get an
+    ///   image with its size not be the same as the `referenceSize`.
+    ///
+    ///   **Example**: With input image size: {100, 200}, 
+    ///   `referenceSize`: {100, 100}, `mode`: `.aspectFit`,
+    ///   you will get an output image with size of {50, 100}, which "fit"s
+    ///   the `referenceSize`.
+    ///
+    ///   If you need an output image exactly to be a specified size, append or use
+    ///   a `CroppingImageProcessor`.
+    public init(referenceSize: CGSize, mode: ContentMode = .none) {
+        self.referenceSize = referenceSize
+        self.targetContentMode = mode
+        
+        if mode == .none {
+            self.identifier = "com.onevcat.Kingfisher.ResizingImageProcessor(\(referenceSize))"
+        } else {
+            self.identifier = "com.onevcat.Kingfisher.ResizingImageProcessor(\(referenceSize), \(mode))"
+        }
+    }
+    
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            return image.kf.scaled(to: options.scaleFactor)
+                        .kf.resize(to: referenceSize, for: targetContentMode)
+        case .data:
+            return (DefaultImageProcessor.default |> self).process(item: item, options: options)
+        }
+    }
+}
+
+/// Processor for adding blur effect to images. `Accelerate.framework` is used underhood for 
+/// a better performance. A simulated Gaussian blur with specified blur radius will be applied.
+public struct BlurImageProcessor: ImageProcessor {
+    
+    /// Identifier of the processor.
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public let identifier: String
+    
+    /// Blur radius for the simulated Gaussian blur.
+    public let blurRadius: CGFloat
+
+    /// Creates a `BlurImageProcessor`
+    ///
+    /// - parameter blurRadius: Blur radius for the simulated Gaussian blur.
+    public init(blurRadius: CGFloat) {
+        self.blurRadius = blurRadius
+        self.identifier = "com.onevcat.Kingfisher.BlurImageProcessor(\(blurRadius))"
+    }
+    
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            let radius = blurRadius * options.scaleFactor
+            return image.kf.scaled(to: options.scaleFactor)
+                        .kf.blurred(withRadius: radius)
+        case .data:
+            return (DefaultImageProcessor.default |> self).process(item: item, options: options)
+        }
+    }
+}
+
+/// Processor for adding an overlay to images. Only CG-based images are supported in macOS.
+public struct OverlayImageProcessor: ImageProcessor {
+    
+    /// Identifier of the processor.
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public let identifier: String
+    
+    /// Overlay color will be used to overlay the input image.
+    public let overlay: KFCrossPlatformColor
+    
+    /// Fraction will be used when overlay the color to image.
+    public let fraction: CGFloat
+    
+    /// Creates an `OverlayImageProcessor`
+    ///
+    /// - parameter overlay:  Overlay color will be used to overlay the input image.
+    /// - parameter fraction: Fraction will be used when overlay the color to image. 
+    ///                       From 0.0 to 1.0. 0.0 means solid color, 1.0 means transparent overlay.
+    public init(overlay: KFCrossPlatformColor, fraction: CGFloat = 0.5) {
+        self.overlay = overlay
+        self.fraction = fraction
+        self.identifier = "com.onevcat.Kingfisher.OverlayImageProcessor(\(overlay.rgbaDescription)_\(fraction))"
+    }
+    
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            return image.kf.scaled(to: options.scaleFactor)
+                        .kf.overlaying(with: overlay, fraction: fraction)
+        case .data:
+            return (DefaultImageProcessor.default |> self).process(item: item, options: options)
+        }
+    }
+}
+
+/// Processor for tint images with color. Only CG-based images are supported.
+public struct TintImageProcessor: ImageProcessor {
+    
+    /// Identifier of the processor.
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public let identifier: String
+    
+    /// Tint color will be used to tint the input image.
+    public let tint: KFCrossPlatformColor
+    
+    /// Creates a `TintImageProcessor`
+    ///
+    /// - parameter tint: Tint color will be used to tint the input image.
+    public init(tint: KFCrossPlatformColor) {
+        self.tint = tint
+        self.identifier = "com.onevcat.Kingfisher.TintImageProcessor(\(tint.rgbaDescription))"
+    }
+    
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            return image.kf.scaled(to: options.scaleFactor)
+                        .kf.tinted(with: tint)
+        case .data:
+            return (DefaultImageProcessor.default |> self).process(item: item, options: options)
+        }
+    }
+}
+
+/// Processor for applying some color control to images. Only CG-based images are supported.
+/// watchOS is not supported.
+public struct ColorControlsProcessor: ImageProcessor {
+    
+    /// Identifier of the processor.
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public let identifier: String
+    
+    /// Brightness changing to image.
+    public let brightness: CGFloat
+    
+    /// Contrast changing to image.
+    public let contrast: CGFloat
+    
+    /// Saturation changing to image.
+    public let saturation: CGFloat
+    
+    /// InputEV changing to image.
+    public let inputEV: CGFloat
+    
+    /// Creates a `ColorControlsProcessor`
+    ///
+    /// - Parameters:
+    ///   - brightness: Brightness changing to image.
+    ///   - contrast: Contrast changing to image.
+    ///   - saturation: Saturation changing to image.
+    ///   - inputEV: InputEV changing to image.
+    public init(brightness: CGFloat, contrast: CGFloat, saturation: CGFloat, inputEV: CGFloat) {
+        self.brightness = brightness
+        self.contrast = contrast
+        self.saturation = saturation
+        self.inputEV = inputEV
+        self.identifier = "com.onevcat.Kingfisher.ColorControlsProcessor(\(brightness)_\(contrast)_\(saturation)_\(inputEV))"
+    }
+    
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            return image.kf.scaled(to: options.scaleFactor)
+                        .kf.adjusted(brightness: brightness, contrast: contrast, saturation: saturation, inputEV: inputEV)
+        case .data:
+            return (DefaultImageProcessor.default |> self).process(item: item, options: options)
+        }
+    }
+}
+
+/// Processor for applying black and white effect to images. Only CG-based images are supported.
+/// watchOS is not supported.
+public struct BlackWhiteProcessor: ImageProcessor {
+    
+    /// Identifier of the processor.
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public let identifier = "com.onevcat.Kingfisher.BlackWhiteProcessor"
+    
+    /// Creates a `BlackWhiteProcessor`
+    public init() {}
+    
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        return ColorControlsProcessor(brightness: 0.0, contrast: 1.0, saturation: 0.0, inputEV: 0.7)
+            .process(item: item, options: options)
+    }
+}
+
+/// Processor for cropping an image. Only CG-based images are supported.
+/// watchOS is not supported.
+public struct CroppingImageProcessor: ImageProcessor {
+    
+    /// Identifier of the processor.
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public let identifier: String
+    
+    /// Target size of output image should be.
+    public let size: CGSize
+    
+    /// Anchor point from which the output size should be calculate.
+    /// The anchor point is consisted by two values between 0.0 and 1.0.
+    /// It indicates a related point in current image. 
+    /// See `CroppingImageProcessor.init(size:anchor:)` for more.
+    public let anchor: CGPoint
+    
+    /// Creates a `CroppingImageProcessor`.
+    ///
+    /// - Parameters:
+    ///   - size: Target size of output image should be.
+    ///   - anchor: The anchor point from which the size should be calculated.
+    ///             Default is `CGPoint(x: 0.5, y: 0.5)`, which means the center of input image.
+    /// - Note:
+    ///   The anchor point is consisted by two values between 0.0 and 1.0.
+    ///   It indicates a related point in current image, eg: (0.0, 0.0) for top-left
+    ///   corner, (0.5, 0.5) for center and (1.0, 1.0) for bottom-right corner.
+    ///   The `size` property of `CroppingImageProcessor` will be used along with
+    ///   `anchor` to calculate a target rectangle in the size of image.
+    ///    
+    ///   The target size will be automatically calculated with a reasonable behavior.
+    ///   For example, when you have an image size of `CGSize(width: 100, height: 100)`,
+    ///   and a target size of `CGSize(width: 20, height: 20)`: 
+    ///   - with a (0.0, 0.0) anchor (top-left), the crop rect will be `{0, 0, 20, 20}`; 
+    ///   - with a (0.5, 0.5) anchor (center), it will be `{40, 40, 20, 20}`
+    ///   - while with a (1.0, 1.0) anchor (bottom-right), it will be `{80, 80, 20, 20}`
+    public init(size: CGSize, anchor: CGPoint = CGPoint(x: 0.5, y: 0.5)) {
+        self.size = size
+        self.anchor = anchor
+        self.identifier = "com.onevcat.Kingfisher.CroppingImageProcessor(\(size)_\(anchor))"
+    }
+    
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            return image.kf.scaled(to: options.scaleFactor)
+                        .kf.crop(to: size, anchorOn: anchor)
+        case .data: return (DefaultImageProcessor.default |> self).process(item: item, options: options)
+        }
+    }
+}
+
+/// Processor for downsampling an image. Compared to `ResizingImageProcessor`, this processor
+/// does not render the images to resize. Instead, it downsamples the input data directly to an
+/// image. It is a more efficient than `ResizingImageProcessor`. Prefer to use `DownsamplingImageProcessor` as possible
+/// as you can than the `ResizingImageProcessor`.
+///
+/// Only CG-based images are supported. Animated images (like GIF) is not supported.
+public struct DownsamplingImageProcessor: ImageProcessor {
+    
+    /// Target size of output image should be. It should be smaller than the size of
+    /// input image. If it is larger, the result image will be the same size of input
+    /// data without downsampling.
+    public let size: CGSize
+    
+    /// Identifier of the processor.
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public let identifier: String
+    
+    /// Creates a `DownsamplingImageProcessor`.
+    ///
+    /// - Parameter size: The target size of the downsample operation.
+    public init(size: CGSize) {
+        self.size = size
+        self.identifier = "com.onevcat.Kingfisher.DownsamplingImageProcessor(\(size))"
+    }
+    
+    /// Processes the input `ImageProcessItem` with this processor.
+    ///
+    /// - Parameters:
+    ///   - item: Input item which will be processed by `self`.
+    ///   - options: Options when processing the item.
+    /// - Returns: The processed image.
+    ///
+    /// - Note: See documentation of `ImageProcessor` protocol for more.
+    public func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
+        switch item {
+        case .image(let image):
+            guard let data = image.kf.data(format: .unknown) else {
+                return nil
+            }
+            return KingfisherWrapper.downsampledImage(data: data, to: size, scale: options.scaleFactor)
+        case .data(let data):
+            return KingfisherWrapper.downsampledImage(data: data, to: size, scale: options.scaleFactor)
+        }
+    }
+}
+
+infix operator |>: AdditionPrecedence
+public func |>(left: ImageProcessor, right: ImageProcessor) -> ImageProcessor {
+    return left.append(another: right)
+}
+
+extension KFCrossPlatformColor {
+    
+    var rgba: (r: CGFloat, g: CGFloat, b: CGFloat, a: CGFloat) {
+        var r: CGFloat = 0
+        var g: CGFloat = 0
+        var b: CGFloat = 0
+        var a: CGFloat = 0
+
+        #if os(macOS)
+        (usingColorSpace(.extendedSRGB) ?? self).getRed(&r, green: &g, blue: &b, alpha: &a)
+        #else
+        getRed(&r, green: &g, blue: &b, alpha: &a)
+        #endif
+        
+        return (r, g, b, a)
+    }
+    
+    var rgbaDescription: String {
+        let components = self.rgba
+        return String(format: "(%.2f,%.2f,%.2f,%.2f)", components.r, components.g, components.b, components.a)
+    }
+}

Pods/Kingfisher/Sources/Image/ImageProgressive.swift

@@ -0,0 +1,353 @@
+//
+//  ImageProgressive.swift
+//  Kingfisher
+//
+//  Created by lixiang on 2019/5/10.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+import CoreGraphics
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+private let sharedProcessingQueue: CallbackQueue =
+    .dispatch(DispatchQueue(label: "com.onevcat.Kingfisher.ImageDownloader.Process"))
+
+public struct ImageProgressive {
+    
+    /// The updating strategy when an intermediate progressive image is generated and about to be set to the hosting view.
+    ///
+    /// - default: Use the progressive image as it is. It is the standard behavior when handling the progressive image.
+    /// - keepCurrent: Discard this progressive image and keep the current displayed one.
+    /// - replace: Replace the image to a new one. If the progressive loading is initialized by a view extension in
+    ///            Kingfisher, the replacing image will be used to update the view.
+    public enum UpdatingStrategy {
+        case `default`
+        case keepCurrent
+        case replace(KFCrossPlatformImage?)
+    }
+    
+    /// A default `ImageProgressive` could be used across. It blurs the progressive loading with the fastest
+    /// scan enabled and scan interval as 0.
+    @available(*, deprecated, message: "Getting a default `ImageProgressive` is deprecated due to its syntax symatic is not clear. Use `ImageProgressive.init` instead.", renamed: "init()")
+    public static let `default` = ImageProgressive(
+        isBlur: true,
+        isFastestScan: true,
+        scanInterval: 0
+    )
+    
+    /// Whether to enable blur effect processing
+    let isBlur: Bool
+    /// Whether to enable the fastest scan
+    let isFastestScan: Bool
+    /// Minimum time interval for each scan
+    let scanInterval: TimeInterval
+    
+    /// Called when an intermediate image is prepared and about to be set to the image view. The return value of this
+    /// delegate will be used to update the hosting view, if any. Otherwise, if there is no hosting view (a.k.a the
+    /// image retrieving is not happening from a view extension method), the returned `UpdatingStrategy` is ignored.
+    public let onImageUpdated = Delegate<KFCrossPlatformImage, UpdatingStrategy>()
+    
+    /// Creates an `ImageProgressive` value with default sets. It blurs the progressive loading with the fastest
+    /// scan enabled and scan interval as 0.
+    public init() {
+        self.init(isBlur: true, isFastestScan: true, scanInterval: 0)
+    }
+    
+    /// Creates an `ImageProgressive` value the given values.
+    /// - Parameters:
+    ///   - isBlur: Whether to enable blur effect processing.
+    ///   - isFastestScan: Whether to enable the fastest scan.
+    ///   - scanInterval: Minimum time interval for each scan.
+    public init(isBlur: Bool,
+                isFastestScan: Bool,
+                scanInterval: TimeInterval
+    )
+    {
+        self.isBlur = isBlur
+        self.isFastestScan = isFastestScan
+        self.scanInterval = scanInterval
+    }
+}
+
+final class ImageProgressiveProvider: DataReceivingSideEffect {
+    
+    var onShouldApply: () -> Bool = { return true }
+    
+    func onDataReceived(_ session: URLSession, task: SessionDataTask, data: Data) {
+
+        DispatchQueue.main.async {
+            guard self.onShouldApply() else { return }
+            self.update(data: task.mutableData, with: task.callbacks)
+        }
+    }
+
+    private let option: ImageProgressive
+    private let refresh: (KFCrossPlatformImage) -> Void
+    
+    private let decoder: ImageProgressiveDecoder
+    private let queue = ImageProgressiveSerialQueue()
+    
+    init?(_ options: KingfisherParsedOptionsInfo,
+          refresh: @escaping (KFCrossPlatformImage) -> Void) {
+        guard let option = options.progressiveJPEG else { return nil }
+        
+        self.option = option
+        self.refresh = refresh
+        self.decoder = ImageProgressiveDecoder(
+            option,
+            processingQueue: options.processingQueue ?? sharedProcessingQueue,
+            creatingOptions: options.imageCreatingOptions
+        )
+    }
+    
+    func update(data: Data, with callbacks: [SessionDataTask.TaskCallback]) {
+        guard !data.isEmpty else { return }
+
+        queue.add(minimum: option.scanInterval) { completion in
+
+            func decode(_ data: Data) {
+                self.decoder.decode(data, with: callbacks) { image in
+                    defer { completion() }
+                    guard self.onShouldApply() else { return }
+                    guard let image = image else { return }
+                    self.refresh(image)
+                }
+            }
+            
+            let semaphore = DispatchSemaphore(value: 0)
+            var onShouldApply: Bool = false
+            
+            CallbackQueue.mainAsync.execute {
+                onShouldApply = self.onShouldApply()
+                semaphore.signal()
+            }
+            semaphore.wait()
+            guard onShouldApply else {
+                self.queue.clean()
+                completion()
+                return
+            }
+
+            if self.option.isFastestScan {
+                decode(self.decoder.scanning(data) ?? Data())
+            } else {
+                self.decoder.scanning(data).forEach { decode($0) }
+            }
+        }
+    }
+}
+
+private final class ImageProgressiveDecoder {
+    
+    private let option: ImageProgressive
+    private let processingQueue: CallbackQueue
+    private let creatingOptions: ImageCreatingOptions
+    private(set) var scannedCount = 0
+    private(set) var scannedIndex = -1
+    
+    init(_ option: ImageProgressive,
+         processingQueue: CallbackQueue,
+         creatingOptions: ImageCreatingOptions) {
+        self.option = option
+        self.processingQueue = processingQueue
+        self.creatingOptions = creatingOptions
+    }
+    
+    func scanning(_ data: Data) -> [Data] {
+        guard data.kf.contains(jpeg: .SOF2) else {
+            return []
+        }
+        guard scannedIndex + 1 < data.count else {
+            return []
+        }
+        
+        var datas: [Data] = []
+        var index = scannedIndex + 1
+        var count = scannedCount
+        
+        while index < data.count - 1 {
+            scannedIndex = index
+            // 0xFF, 0xDA - Start Of Scan
+            let SOS = ImageFormat.JPEGMarker.SOS.bytes
+            if data[index] == SOS[0], data[index + 1] == SOS[1] {
+                if count > 0 {
+                    datas.append(data[0 ..< index])
+                }
+                count += 1
+            }
+            index += 1
+        }
+        
+        // Found more scans this the previous time
+        guard count > scannedCount else { return [] }
+        scannedCount = count
+        
+        // `> 1` checks that we've received a first scan (SOS) and then received
+        // and also received a second scan (SOS). This way we know that we have
+        // at least one full scan available.
+        guard count > 1 else { return [] }
+        return datas
+    }
+    
+    func scanning(_ data: Data) -> Data? {
+        guard data.kf.contains(jpeg: .SOF2) else {
+            return nil
+        }
+        guard scannedIndex + 1 < data.count else {
+            return nil
+        }
+        
+        var index = scannedIndex + 1
+        var count = scannedCount
+        var lastSOSIndex = 0
+        
+        while index < data.count - 1 {
+            scannedIndex = index
+            // 0xFF, 0xDA - Start Of Scan
+            let SOS = ImageFormat.JPEGMarker.SOS.bytes
+            if data[index] == SOS[0], data[index + 1] == SOS[1] {
+                lastSOSIndex = index
+                count += 1
+            }
+            index += 1
+        }
+        
+        // Found more scans this the previous time
+        guard count > scannedCount else { return nil }
+        scannedCount = count
+        
+        // `> 1` checks that we've received a first scan (SOS) and then received
+        // and also received a second scan (SOS). This way we know that we have
+        // at least one full scan available.
+        guard count > 1 && lastSOSIndex > 0 else { return nil }
+        return data[0 ..< lastSOSIndex]
+    }
+    
+    func decode(_ data: Data,
+                with callbacks: [SessionDataTask.TaskCallback],
+                completion: @escaping (KFCrossPlatformImage?) -> Void) {
+        guard data.kf.contains(jpeg: .SOF2) else {
+            CallbackQueue.mainCurrentOrAsync.execute { completion(nil) }
+            return
+        }
+        
+        func processing(_ data: Data) {
+            let processor = ImageDataProcessor(
+                data: data,
+                callbacks: callbacks,
+                processingQueue: processingQueue
+            )
+            processor.onImageProcessed.delegate(on: self) { (self, result) in
+                guard let image = try? result.0.get() else {
+                    CallbackQueue.mainCurrentOrAsync.execute { completion(nil) }
+                    return
+                }
+                
+                CallbackQueue.mainCurrentOrAsync.execute { completion(image) }
+            }
+            processor.process()
+        }
+        
+        // Blur partial images.
+        let count = scannedCount
+        
+        if option.isBlur, count < 6 {
+            processingQueue.execute {
+                // Progressively reduce blur as we load more scans.
+                let image = KingfisherWrapper<KFCrossPlatformImage>.image(
+                    data: data,
+                    options: self.creatingOptions
+                )
+                let radius = max(2, 14 - count * 4)
+                let temp = image?.kf.blurred(withRadius: CGFloat(radius))
+                processing(temp?.kf.data(format: .JPEG) ?? data)
+            }
+            
+        } else {
+            processing(data)
+        }
+    }
+}
+
+private final class ImageProgressiveSerialQueue {
+    typealias ClosureCallback = ((@escaping () -> Void)) -> Void
+    
+    private let queue: DispatchQueue
+    private var items: [DispatchWorkItem] = []
+    private var notify: (() -> Void)?
+    private var lastTime: TimeInterval?
+
+    init() {
+        self.queue = DispatchQueue(label: "com.onevcat.Kingfisher.ImageProgressive.SerialQueue")
+    }
+    
+    func add(minimum interval: TimeInterval, closure: @escaping ClosureCallback) {
+        let completion = { [weak self] in
+            guard let self = self else { return }
+            
+            self.queue.async { [weak self] in
+                guard let self = self else { return }
+                guard !self.items.isEmpty else { return }
+                
+                self.items.removeFirst()
+                
+                if let next = self.items.first {
+                    self.queue.asyncAfter(
+                        deadline: .now() + interval,
+                        execute: next
+                    )
+                    
+                } else {
+                    self.lastTime = Date().timeIntervalSince1970
+                    self.notify?()
+                    self.notify = nil
+                }
+            }
+        }
+        
+        queue.async { [weak self] in
+            guard let self = self else { return }
+            
+            let item = DispatchWorkItem {
+                closure(completion)
+            }
+            if self.items.isEmpty {
+                let difference = Date().timeIntervalSince1970 - (self.lastTime ?? 0)
+                let delay = difference < interval ? interval - difference : 0
+                self.queue.asyncAfter(deadline: .now() + delay, execute: item)
+            }
+            self.items.append(item)
+        }
+    }
+    
+    func clean() {
+        queue.async { [weak self] in
+            guard let self = self else { return }
+            self.items.forEach { $0.cancel() }
+            self.items.removeAll()
+        }
+    }
+}

Pods/Kingfisher/Sources/Image/ImageTransition.swift

@@ -0,0 +1,118 @@
+//
+//  ImageTransition.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 15/9/18.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+#if os(iOS) || os(tvOS) || os(visionOS)
+import UIKit
+
+/// Transition effect which will be used when an image downloaded and set by `UIImageView`
+/// extension API in Kingfisher. You can assign an enum value with transition duration as
+/// an item in `KingfisherOptionsInfo` to enable the animation transition.
+///
+/// Apple's UIViewAnimationOptions is used under the hood.
+/// For custom transition, you should specified your own transition options, animations and
+/// completion handler as well.
+///
+/// - none: No animation transition.
+/// - fade: Fade in the loaded image in a given duration.
+/// - flipFromLeft: Flip from left transition.
+/// - flipFromRight: Flip from right transition.
+/// - flipFromTop: Flip from top transition.
+/// - flipFromBottom: Flip from bottom transition.
+/// - custom: Custom transition.
+public enum ImageTransition {
+    /// No animation transition.
+    case none
+    /// Fade in the loaded image in a given duration.
+    case fade(TimeInterval)
+    /// Flip from left transition.
+    case flipFromLeft(TimeInterval)
+    /// Flip from right transition.
+    case flipFromRight(TimeInterval)
+    /// Flip from top transition.
+    case flipFromTop(TimeInterval)
+    /// Flip from bottom transition.
+    case flipFromBottom(TimeInterval)
+    /// Custom transition defined by a general animation block.
+    ///    - duration: The time duration of this custom transition.
+    ///    - options: `UIView.AnimationOptions` should be used in the transition.
+    ///    - animations: The animation block will be applied when setting image.
+    ///    - completion: A block called when the transition animation finishes.
+    case custom(duration: TimeInterval,
+                 options: UIView.AnimationOptions,
+              animations: ((UIImageView, UIImage) -> Void)?,
+              completion: ((Bool) -> Void)?)
+    
+    var duration: TimeInterval {
+        switch self {
+        case .none:                          return 0
+        case .fade(let duration):            return duration
+            
+        case .flipFromLeft(let duration):    return duration
+        case .flipFromRight(let duration):   return duration
+        case .flipFromTop(let duration):     return duration
+        case .flipFromBottom(let duration):  return duration
+            
+        case .custom(let duration, _, _, _): return duration
+        }
+    }
+    
+    var animationOptions: UIView.AnimationOptions {
+        switch self {
+        case .none:                         return []
+        case .fade:                         return .transitionCrossDissolve
+            
+        case .flipFromLeft:                 return .transitionFlipFromLeft
+        case .flipFromRight:                return .transitionFlipFromRight
+        case .flipFromTop:                  return .transitionFlipFromTop
+        case .flipFromBottom:               return .transitionFlipFromBottom
+            
+        case .custom(_, let options, _, _): return options
+        }
+    }
+    
+    var animations: ((UIImageView, UIImage) -> Void)? {
+        switch self {
+        case .custom(_, _, let animations, _): return animations
+        default: return { $0.image = $1 }
+        }
+    }
+    
+    var completion: ((Bool) -> Void)? {
+        switch self {
+        case .custom(_, _, _, let completion): return completion
+        default: return nil
+        }
+    }
+}
+#else
+// Just a placeholder for compiling on macOS.
+public enum ImageTransition {
+    case none
+    /// This is a placeholder on macOS now. It is for SwiftUI (KFImage) to identify the fade option only.
+    case fade(TimeInterval)
+}
+#endif

Pods/Kingfisher/Sources/Image/Placeholder.swift

@@ -0,0 +1,82 @@
+//
+//  Placeholder.swift
+//  Kingfisher
+//
+//  Created by Tieme van Veen on 28/08/2017.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if !os(watchOS)
+
+#if canImport(AppKit) && !targetEnvironment(macCatalyst)
+import AppKit
+#endif
+
+#if canImport(UIKit)
+import UIKit
+#endif
+
+/// Represents a placeholder type which could be set while loading as well as
+/// loading finished without getting an image.
+public protocol Placeholder {
+    
+    /// How the placeholder should be added to a given image view.
+    func add(to imageView: KFCrossPlatformImageView)
+    
+    /// How the placeholder should be removed from a given image view.
+    func remove(from imageView: KFCrossPlatformImageView)
+}
+
+/// Default implementation of an image placeholder. The image will be set or
+/// reset directly for `image` property of the image view.
+extension KFCrossPlatformImage: Placeholder {
+    /// How the placeholder should be added to a given image view.
+    public func add(to imageView: KFCrossPlatformImageView) { imageView.image = self }
+
+    /// How the placeholder should be removed from a given image view.
+    public func remove(from imageView: KFCrossPlatformImageView) { imageView.image = nil }
+}
+
+/// Default implementation of an arbitrary view as placeholder. The view will be 
+/// added as a subview when adding and be removed from its super view when removing.
+///
+/// To use your customize View type as placeholder, simply let it conforming to 
+/// `Placeholder` by `extension MyView: Placeholder {}`.
+extension Placeholder where Self: KFCrossPlatformView {
+    
+    /// How the placeholder should be added to a given image view.
+    public func add(to imageView: KFCrossPlatformImageView) {
+        imageView.addSubview(self)
+        translatesAutoresizingMaskIntoConstraints = false
+
+        centerXAnchor.constraint(equalTo: imageView.centerXAnchor).isActive = true
+        centerYAnchor.constraint(equalTo: imageView.centerYAnchor).isActive = true
+        heightAnchor.constraint(equalTo: imageView.heightAnchor).isActive = true
+        widthAnchor.constraint(equalTo: imageView.widthAnchor).isActive = true
+    }
+
+    /// How the placeholder should be removed from a given image view.
+    public func remove(from imageView: KFCrossPlatformImageView) {
+        removeFromSuperview()
+    }
+}
+
+#endif

Pods/Kingfisher/Sources/Networking/AuthenticationChallengeResponsable.swift

@@ -0,0 +1,94 @@
+//
+//  AuthenticationChallengeResponsable.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2018/10/11.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+@available(*, deprecated, message: "Typo. Use `AuthenticationChallengeResponsible` instead", renamed: "AuthenticationChallengeResponsible")
+public typealias AuthenticationChallengeResponsable = AuthenticationChallengeResponsible
+
+/// Protocol indicates that an authentication challenge could be handled.
+public protocol AuthenticationChallengeResponsible: AnyObject {
+
+    /// Called when a session level authentication challenge is received.
+    /// This method provide a chance to handle and response to the authentication
+    /// challenge before downloading could start.
+    ///
+    /// - Parameters:
+    ///   - downloader: The downloader which receives this challenge.
+    ///   - challenge: An object that contains the request for authentication.
+    ///   - completionHandler: A handler that your delegate method must call.
+    ///
+    /// - Note: This method is a forward from `URLSessionDelegate.urlSession(:didReceiveChallenge:completionHandler:)`.
+    ///         Please refer to the document of it in `URLSessionDelegate`.
+    func downloader(
+        _ downloader: ImageDownloader,
+        didReceive challenge: URLAuthenticationChallenge,
+        completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void)
+
+    /// Called when a task level authentication challenge is received.
+    /// This method provide a chance to handle and response to the authentication
+    /// challenge before downloading could start.
+    ///
+    /// - Parameters:
+    ///   - downloader: The downloader which receives this challenge.
+    ///   - task: The task whose request requires authentication.
+    ///   - challenge: An object that contains the request for authentication.
+    ///   - completionHandler: A handler that your delegate method must call.
+    func downloader(
+        _ downloader: ImageDownloader,
+        task: URLSessionTask,
+        didReceive challenge: URLAuthenticationChallenge,
+        completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void)
+}
+
+extension AuthenticationChallengeResponsible {
+
+    public func downloader(
+        _ downloader: ImageDownloader,
+        didReceive challenge: URLAuthenticationChallenge,
+        completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void)
+    {
+        if challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust {
+            if let trustedHosts = downloader.trustedHosts, trustedHosts.contains(challenge.protectionSpace.host) {
+                let credential = URLCredential(trust: challenge.protectionSpace.serverTrust!)
+                completionHandler(.useCredential, credential)
+                return
+            }
+        }
+
+        completionHandler(.performDefaultHandling, nil)
+    }
+
+    public func downloader(
+        _ downloader: ImageDownloader,
+        task: URLSessionTask,
+        didReceive challenge: URLAuthenticationChallenge,
+        completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void)
+    {
+        completionHandler(.performDefaultHandling, nil)
+    }
+
+}

Pods/Kingfisher/Sources/Networking/ImageDataProcessor.swift

@@ -0,0 +1,74 @@
+//
+//  ImageDataProcessor.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2018/10/11.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+private let sharedProcessingQueue: CallbackQueue =
+    .dispatch(DispatchQueue(label: "com.onevcat.Kingfisher.ImageDownloader.Process"))
+
+// Handles image processing work on an own process queue.
+class ImageDataProcessor {
+    let data: Data
+    let callbacks: [SessionDataTask.TaskCallback]
+    let queue: CallbackQueue
+
+    // Note: We have an optimization choice there, to reduce queue dispatch by checking callback
+    // queue settings in each option...
+    let onImageProcessed = Delegate<(Result<KFCrossPlatformImage, KingfisherError>, SessionDataTask.TaskCallback), Void>()
+
+    init(data: Data, callbacks: [SessionDataTask.TaskCallback], processingQueue: CallbackQueue?) {
+        self.data = data
+        self.callbacks = callbacks
+        self.queue = processingQueue ?? sharedProcessingQueue
+    }
+
+    func process() {
+        queue.execute(doProcess)
+    }
+
+    private func doProcess() {
+        var processedImages = [String: KFCrossPlatformImage]()
+        for callback in callbacks {
+            let processor = callback.options.processor
+            var image = processedImages[processor.identifier]
+            if image == nil {
+                image = processor.process(item: .data(data), options: callback.options)
+                processedImages[processor.identifier] = image
+            }
+
+            let result: Result<KFCrossPlatformImage, KingfisherError>
+            if let image = image {
+                let finalImage = callback.options.backgroundDecode ? image.kf.decoded : image
+                result = .success(finalImage)
+            } else {
+                let error = KingfisherError.processorError(
+                    reason: .processingFailed(processor: processor, item: .data(data)))
+                result = .failure(error)
+            }
+            onImageProcessed.call((result, callback))
+        }
+    }
+}

Pods/Kingfisher/Sources/Networking/ImageDownloader.swift

@@ -0,0 +1,502 @@
+//
+//  ImageDownloader.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 15/4/6.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+typealias DownloadResult = Result<ImageLoadingResult, KingfisherError>
+
+/// Represents a success result of an image downloading progress.
+public struct ImageLoadingResult {
+
+    /// The downloaded image.
+    public let image: KFCrossPlatformImage
+
+    /// Original URL of the image request.
+    public let url: URL?
+
+    /// The raw data received from downloader.
+    public let originalData: Data
+
+    /// Creates an `ImageDownloadResult`
+    ///
+    /// - parameter image: Image of the download result
+    /// - parameter url: URL from where the image was downloaded from
+    /// - parameter originalData: The image's binary data
+    public init(image: KFCrossPlatformImage, url: URL? = nil, originalData: Data) {
+        self.image = image
+        self.url = url
+        self.originalData = originalData
+    }
+}
+
+/// Represents a task of an image downloading process.
+public struct DownloadTask {
+
+    /// The `SessionDataTask` object bounded to this download task. Multiple `DownloadTask`s could refer
+    /// to a same `sessionTask`. This is an optimization in Kingfisher to prevent multiple downloading task
+    /// for the same URL resource at the same time.
+    ///
+    /// When you `cancel` a `DownloadTask`, this `SessionDataTask` and its cancel token will be pass through.
+    /// You can use them to identify the cancelled task.
+    public let sessionTask: SessionDataTask
+
+    /// The cancel token which is used to cancel the task. This is only for identify the task when it is cancelled.
+    /// To cancel a `DownloadTask`, use `cancel` instead.
+    public let cancelToken: SessionDataTask.CancelToken
+
+    /// Cancel this task if it is running. It will do nothing if this task is not running.
+    ///
+    /// - Note:
+    /// In Kingfisher, there is an optimization to prevent starting another download task if the target URL is being
+    /// downloading. However, even when internally no new session task created, a `DownloadTask` will be still created
+    /// and returned when you call related methods, but it will share the session downloading task with a previous task.
+    /// In this case, if multiple `DownloadTask`s share a single session download task, cancelling a `DownloadTask`
+    /// does not affect other `DownloadTask`s.
+    ///
+    /// If you need to cancel all `DownloadTask`s of a url, use `ImageDownloader.cancel(url:)`. If you need to cancel
+    /// all downloading tasks of an `ImageDownloader`, use `ImageDownloader.cancelAll()`.
+    public func cancel() {
+        sessionTask.cancel(token: cancelToken)
+    }
+}
+
+extension DownloadTask {
+    enum WrappedTask {
+        case download(DownloadTask)
+        case dataProviding
+
+        func cancel() {
+            switch self {
+            case .download(let task): task.cancel()
+            case .dataProviding: break
+            }
+        }
+
+        var value: DownloadTask? {
+            switch self {
+            case .download(let task): return task
+            case .dataProviding: return nil
+            }
+        }
+    }
+}
+
+/// Represents a downloading manager for requesting the image with a URL from server.
+open class ImageDownloader {
+
+    // MARK: Singleton
+    /// The default downloader.
+    public static let `default` = ImageDownloader(name: "default")
+
+    // MARK: Public Properties
+    /// The duration before the downloading is timeout. Default is 15 seconds.
+    open var downloadTimeout: TimeInterval = 15.0
+    
+    /// A set of trusted hosts when receiving server trust challenges. A challenge with host name contained in this
+    /// set will be ignored. You can use this set to specify the self-signed site. It only will be used if you don't
+    /// specify the `authenticationChallengeResponder`.
+    ///
+    /// If `authenticationChallengeResponder` is set, this property will be ignored and the implementation of
+    /// `authenticationChallengeResponder` will be used instead.
+    open var trustedHosts: Set<String>?
+    
+    /// Use this to set supply a configuration for the downloader. By default,
+    /// NSURLSessionConfiguration.ephemeralSessionConfiguration() will be used.
+    ///
+    /// You could change the configuration before a downloading task starts.
+    /// A configuration without persistent storage for caches is requested for downloader working correctly.
+    open var sessionConfiguration = URLSessionConfiguration.ephemeral {
+        didSet {
+            session.invalidateAndCancel()
+            session = URLSession(configuration: sessionConfiguration, delegate: sessionDelegate, delegateQueue: nil)
+        }
+    }
+    open var sessionDelegate: SessionDelegate {
+        didSet {
+            session.invalidateAndCancel()
+            session = URLSession(configuration: sessionConfiguration, delegate: sessionDelegate, delegateQueue: nil)
+            setupSessionHandler()
+        }
+    }
+    
+    /// Whether the download requests should use pipeline or not. Default is false.
+    open var requestsUsePipelining = false
+
+    /// Delegate of this `ImageDownloader` object. See `ImageDownloaderDelegate` protocol for more.
+    open weak var delegate: ImageDownloaderDelegate?
+    
+    /// A responder for authentication challenge. 
+    /// Downloader will forward the received authentication challenge for the downloading session to this responder.
+    open weak var authenticationChallengeResponder: AuthenticationChallengeResponsible?
+
+    private let name: String
+    private var session: URLSession
+
+    // MARK: Initializers
+
+    /// Creates a downloader with name.
+    ///
+    /// - Parameter name: The name for the downloader. It should not be empty.
+    public init(name: String) {
+        if name.isEmpty {
+            fatalError("[Kingfisher] You should specify a name for the downloader. "
+                + "A downloader with empty name is not permitted.")
+        }
+
+        self.name = name
+
+        sessionDelegate = SessionDelegate()
+        session = URLSession(
+            configuration: sessionConfiguration,
+            delegate: sessionDelegate,
+            delegateQueue: nil)
+
+        authenticationChallengeResponder = self
+        setupSessionHandler()
+    }
+
+    deinit { session.invalidateAndCancel() }
+
+    private func setupSessionHandler() {
+        sessionDelegate.onReceiveSessionChallenge.delegate(on: self) { (self, invoke) in
+            self.authenticationChallengeResponder?.downloader(self, didReceive: invoke.1, completionHandler: invoke.2)
+        }
+        sessionDelegate.onReceiveSessionTaskChallenge.delegate(on: self) { (self, invoke) in
+            self.authenticationChallengeResponder?.downloader(
+                self, task: invoke.1, didReceive: invoke.2, completionHandler: invoke.3)
+        }
+        sessionDelegate.onValidStatusCode.delegate(on: self) { (self, code) in
+            return (self.delegate ?? self).isValidStatusCode(code, for: self)
+        }
+        sessionDelegate.onResponseReceived.delegate(on: self) { (self, invoke) in
+            (self.delegate ?? self).imageDownloader(self, didReceive: invoke.0, completionHandler: invoke.1)
+        }
+        sessionDelegate.onDownloadingFinished.delegate(on: self) { (self, value) in
+            let (url, result) = value
+            do {
+                let value = try result.get()
+                self.delegate?.imageDownloader(self, didFinishDownloadingImageForURL: url, with: value, error: nil)
+            } catch {
+                self.delegate?.imageDownloader(self, didFinishDownloadingImageForURL: url, with: nil, error: error)
+            }
+        }
+        sessionDelegate.onDidDownloadData.delegate(on: self) { (self, task) in
+            return (self.delegate ?? self).imageDownloader(self, didDownload: task.mutableData, with: task)
+        }
+    }
+
+    // Wraps `completionHandler` to `onCompleted` respectively.
+    private func createCompletionCallBack(_ completionHandler: ((DownloadResult) -> Void)?) -> Delegate<DownloadResult, Void>? {
+        return completionHandler.map { block -> Delegate<DownloadResult, Void> in
+
+            let delegate =  Delegate<Result<ImageLoadingResult, KingfisherError>, Void>()
+            delegate.delegate(on: self) { (self, callback) in
+                block(callback)
+            }
+            return delegate
+        }
+    }
+
+    private func createTaskCallback(
+        _ completionHandler: ((DownloadResult) -> Void)?,
+        options: KingfisherParsedOptionsInfo
+    ) -> SessionDataTask.TaskCallback
+    {
+        return SessionDataTask.TaskCallback(
+            onCompleted: createCompletionCallBack(completionHandler),
+            options: options
+        )
+    }
+
+    private func createDownloadContext(
+        with url: URL,
+        options: KingfisherParsedOptionsInfo,
+        done: @escaping ((Result<DownloadingContext, KingfisherError>) -> Void)
+    )
+    {
+        func checkRequestAndDone(r: URLRequest) {
+
+            // There is a possibility that request modifier changed the url to `nil` or empty.
+            // In this case, throw an error.
+            guard let url = r.url, !url.absoluteString.isEmpty else {
+                done(.failure(KingfisherError.requestError(reason: .invalidURL(request: r))))
+                return
+            }
+
+            done(.success(DownloadingContext(url: url, request: r, options: options)))
+        }
+
+        // Creates default request.
+        var request = URLRequest(url: url, cachePolicy: .reloadIgnoringLocalCacheData, timeoutInterval: downloadTimeout)
+        request.httpShouldUsePipelining = requestsUsePipelining
+        if #available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *) , options.lowDataModeSource != nil {
+            request.allowsConstrainedNetworkAccess = false
+        }
+
+        if let requestModifier = options.requestModifier {
+            // Modifies request before sending.
+            requestModifier.modified(for: request) { result in
+                guard let finalRequest = result else {
+                    done(.failure(KingfisherError.requestError(reason: .emptyRequest)))
+                    return
+                }
+                checkRequestAndDone(r: finalRequest)
+            }
+        } else {
+            checkRequestAndDone(r: request)
+        }
+    }
+
+    private func addDownloadTask(
+        context: DownloadingContext,
+        callback: SessionDataTask.TaskCallback
+    ) -> DownloadTask
+    {
+        // Ready to start download. Add it to session task manager (`sessionHandler`)
+        let downloadTask: DownloadTask
+        if let existingTask = sessionDelegate.task(for: context.url) {
+            downloadTask = sessionDelegate.append(existingTask, callback: callback)
+        } else {
+            let sessionDataTask = session.dataTask(with: context.request)
+            sessionDataTask.priority = context.options.downloadPriority
+            downloadTask = sessionDelegate.add(sessionDataTask, url: context.url, callback: callback)
+        }
+        return downloadTask
+    }
+
+
+    private func reportWillDownloadImage(url: URL, request: URLRequest) {
+        delegate?.imageDownloader(self, willDownloadImageForURL: url, with: request)
+    }
+
+    private func reportDidDownloadImageData(result: Result<(Data, URLResponse?), KingfisherError>, url: URL) {
+        var response: URLResponse?
+        var err: Error?
+        do {
+            response = try result.get().1
+        } catch {
+            err = error
+        }
+        self.delegate?.imageDownloader(
+            self,
+            didFinishDownloadingImageForURL: url,
+            with: response,
+            error: err
+        )
+    }
+
+    private func reportDidProcessImage(
+        result: Result<KFCrossPlatformImage, KingfisherError>, url: URL, response: URLResponse?
+    )
+    {
+        if let image = try? result.get() {
+            self.delegate?.imageDownloader(self, didDownload: image, for: url, with: response)
+        }
+
+    }
+
+    private func startDownloadTask(
+        context: DownloadingContext,
+        callback: SessionDataTask.TaskCallback
+    ) -> DownloadTask
+    {
+
+        let downloadTask = addDownloadTask(context: context, callback: callback)
+
+        let sessionTask = downloadTask.sessionTask
+        guard !sessionTask.started else {
+            return downloadTask
+        }
+
+        sessionTask.onTaskDone.delegate(on: self) { (self, done) in
+            // Underlying downloading finishes.
+            // result: Result<(Data, URLResponse?)>, callbacks: [TaskCallback]
+            let (result, callbacks) = done
+
+            // Before processing the downloaded data.
+            self.reportDidDownloadImageData(result: result, url: context.url)
+
+            switch result {
+            // Download finished. Now process the data to an image.
+            case .success(let (data, response)):
+                let processor = ImageDataProcessor(
+                    data: data, callbacks: callbacks, processingQueue: context.options.processingQueue
+                )
+                processor.onImageProcessed.delegate(on: self) { (self, done) in
+                    // `onImageProcessed` will be called for `callbacks.count` times, with each
+                    // `SessionDataTask.TaskCallback` as the input parameter.
+                    // result: Result<Image>, callback: SessionDataTask.TaskCallback
+                    let (result, callback) = done
+
+                    self.reportDidProcessImage(result: result, url: context.url, response: response)
+
+                    let imageResult = result.map { ImageLoadingResult(image: $0, url: context.url, originalData: data) }
+                    let queue = callback.options.callbackQueue
+                    queue.execute { callback.onCompleted?.call(imageResult) }
+                }
+                processor.process()
+
+            case .failure(let error):
+                callbacks.forEach { callback in
+                    let queue = callback.options.callbackQueue
+                    queue.execute { callback.onCompleted?.call(.failure(error)) }
+                }
+            }
+        }
+
+        reportWillDownloadImage(url: context.url, request: context.request)
+        sessionTask.resume()
+        return downloadTask
+    }
+
+    // MARK: Downloading Task
+    /// Downloads an image with a URL and option. Invoked internally by Kingfisher. Subclasses must invoke super.
+    ///
+    /// - Parameters:
+    ///   - url: Target URL.
+    ///   - options: The options could control download behavior. See `KingfisherOptionsInfo`.
+    ///   - completionHandler: Called when the download progress finishes. This block will be called in the queue
+    ///                        defined in `.callbackQueue` in `options` parameter.
+    /// - Returns: A downloading task. You could call `cancel` on it to stop the download task.
+    @discardableResult
+    open func downloadImage(
+        with url: URL,
+        options: KingfisherParsedOptionsInfo,
+        completionHandler: ((Result<ImageLoadingResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        var downloadTask: DownloadTask?
+        createDownloadContext(with: url, options: options) { result in
+            switch result {
+            case .success(let context):
+                // `downloadTask` will be set if the downloading started immediately. This is the case when no request
+                // modifier or a sync modifier (`ImageDownloadRequestModifier`) is used. Otherwise, when an
+                // `AsyncImageDownloadRequestModifier` is used the returned `downloadTask` of this method will be `nil`
+                // and the actual "delayed" task is given in `AsyncImageDownloadRequestModifier.onDownloadTaskStarted`
+                // callback.
+                downloadTask = self.startDownloadTask(
+                    context: context,
+                    callback: self.createTaskCallback(completionHandler, options: options)
+                )
+                if let modifier = options.requestModifier {
+                    modifier.onDownloadTaskStarted?(downloadTask)
+                }
+            case .failure(let error):
+                options.callbackQueue.execute {
+                    completionHandler?(.failure(error))
+                }
+            }
+        }
+
+        return downloadTask
+    }
+
+    /// Downloads an image with a URL and option.
+    ///
+    /// - Parameters:
+    ///   - url: Target URL.
+    ///   - options: The options could control download behavior. See `KingfisherOptionsInfo`.
+    ///   - progressBlock: Called when the download progress updated. This block will be always be called in main queue.
+    ///   - completionHandler: Called when the download progress finishes. This block will be called in the queue
+    ///                        defined in `.callbackQueue` in `options` parameter.
+    /// - Returns: A downloading task. You could call `cancel` on it to stop the download task.
+    @discardableResult
+    open func downloadImage(
+        with url: URL,
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: DownloadProgressBlock? = nil,
+        completionHandler: ((Result<ImageLoadingResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        var info = KingfisherParsedOptionsInfo(options)
+        if let block = progressBlock {
+            info.onDataReceived = (info.onDataReceived ?? []) + [ImageLoadingProgressSideEffect(block)]
+        }
+        return downloadImage(
+            with: url,
+            options: info,
+            completionHandler: completionHandler)
+    }
+
+    /// Downloads an image with a URL and option.
+    ///
+    /// - Parameters:
+    ///   - url: Target URL.
+    ///   - options: The options could control download behavior. See `KingfisherOptionsInfo`.
+    ///   - completionHandler: Called when the download progress finishes. This block will be called in the queue
+    ///                        defined in `.callbackQueue` in `options` parameter.
+    /// - Returns: A downloading task. You could call `cancel` on it to stop the download task.
+    @discardableResult
+    open func downloadImage(
+        with url: URL,
+        options: KingfisherOptionsInfo? = nil,
+        completionHandler: ((Result<ImageLoadingResult, KingfisherError>) -> Void)? = nil) -> DownloadTask?
+    {
+        downloadImage(
+            with: url,
+            options: KingfisherParsedOptionsInfo(options),
+            completionHandler: completionHandler
+        )
+    }
+}
+
+// MARK: Cancelling Task
+extension ImageDownloader {
+
+    /// Cancel all downloading tasks for this `ImageDownloader`. It will trigger the completion handlers
+    /// for all not-yet-finished downloading tasks.
+    ///
+    /// If you need to only cancel a certain task, call `cancel()` on the `DownloadTask`
+    /// returned by the downloading methods. If you need to cancel all `DownloadTask`s of a certain url,
+    /// use `ImageDownloader.cancel(url:)`.
+    public func cancelAll() {
+        sessionDelegate.cancelAll()
+    }
+
+    /// Cancel all downloading tasks for a given URL. It will trigger the completion handlers for
+    /// all not-yet-finished downloading tasks for the URL.
+    ///
+    /// - Parameter url: The URL which you want to cancel downloading.
+    public func cancel(url: URL) {
+        sessionDelegate.cancel(url: url)
+    }
+}
+
+// Use the default implementation from extension of `AuthenticationChallengeResponsible`.
+extension ImageDownloader: AuthenticationChallengeResponsible {}
+
+// Use the default implementation from extension of `ImageDownloaderDelegate`.
+extension ImageDownloader: ImageDownloaderDelegate {}
+
+extension ImageDownloader {
+    struct DownloadingContext {
+        let url: URL
+        let request: URLRequest
+        let options: KingfisherParsedOptionsInfo
+    }
+}

Pods/Kingfisher/Sources/Networking/ImageDownloaderDelegate.swift

@@ -0,0 +1,189 @@
+//
+//  ImageDownloaderDelegate.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2018/10/11.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+/// Protocol of `ImageDownloader`. This protocol provides a set of methods which are related to image downloader
+/// working stages and rules.
+public protocol ImageDownloaderDelegate: AnyObject {
+
+    /// Called when the `ImageDownloader` object will start downloading an image from a specified URL.
+    ///
+    /// - Parameters:
+    ///   - downloader: The `ImageDownloader` object which is used for the downloading operation.
+    ///   - url: URL of the starting request.
+    ///   - request: The request object for the download process.
+    ///
+    func imageDownloader(_ downloader: ImageDownloader, willDownloadImageForURL url: URL, with request: URLRequest?)
+
+    /// Called when the `ImageDownloader` completes a downloading request with success or failure.
+    ///
+    /// - Parameters:
+    ///   - downloader: The `ImageDownloader` object which is used for the downloading operation.
+    ///   - url: URL of the original request URL.
+    ///   - response: The response object of the downloading process.
+    ///   - error: The error in case of failure.
+    ///
+    func imageDownloader(
+        _ downloader: ImageDownloader,
+        didFinishDownloadingImageForURL url: URL,
+        with response: URLResponse?,
+        error: Error?)
+
+    /// Called when the `ImageDownloader` object successfully downloaded image data from specified URL. This is
+    /// your last chance to verify or modify the downloaded data before Kingfisher tries to perform addition
+    /// processing on the image data.
+    ///
+    /// - Parameters:
+    ///   - downloader: The `ImageDownloader` object which is used for the downloading operation.
+    ///   - data: The original downloaded data.
+    ///   - dataTask: The data task contains request and response information of the download.
+    /// - Note:
+    ///   This can be used to pre-process raw image data before creation of `Image` instance (i.e.
+    ///   decrypting or verification). If `nil` returned, the processing is interrupted and a `KingfisherError` with
+    ///   `ResponseErrorReason.dataModifyingFailed` will be raised. You could use this fact to stop the image
+    ///   processing flow if you find the data is corrupted or malformed.
+    ///
+    ///  If this method is implemented, `imageDownloader(_:didDownload:for:)` will not be called anymore.
+    func imageDownloader(_ downloader: ImageDownloader, didDownload data: Data, with dataTask: SessionDataTask) -> Data?
+  
+    /// Called when the `ImageDownloader` object successfully downloaded image data from specified URL. This is
+    /// your last chance to verify or modify the downloaded data before Kingfisher tries to perform addition
+    /// processing on the image data.
+    ///
+    /// - Parameters:
+    ///   - downloader: The `ImageDownloader` object which is used for the downloading operation.
+    ///   - data: The original downloaded data.
+    ///   - url: The URL of the original request URL.
+    /// - Returns: The data from which Kingfisher should use to create an image. You need to provide valid data
+    ///            which content is one of the supported image file format. Kingfisher will perform process on this
+    ///            data and try to convert it to an image object.
+    /// - Note:
+    ///   This can be used to pre-process raw image data before creation of `Image` instance (i.e.
+    ///   decrypting or verification). If `nil` returned, the processing is interrupted and a `KingfisherError` with
+    ///   `ResponseErrorReason.dataModifyingFailed` will be raised. You could use this fact to stop the image
+    ///   processing flow if you find the data is corrupted or malformed.
+    ///
+    ///   If `imageDownloader(_:didDownload:with:)` is implemented, this method will not be called anymore.
+    func imageDownloader(_ downloader: ImageDownloader, didDownload data: Data, for url: URL) -> Data?
+
+    /// Called when the `ImageDownloader` object successfully downloads and processes an image from specified URL.
+    ///
+    /// - Parameters:
+    ///   - downloader: The `ImageDownloader` object which is used for the downloading operation.
+    ///   - image: The downloaded and processed image.
+    ///   - url: URL of the original request URL.
+    ///   - response: The original response object of the downloading process.
+    ///
+    func imageDownloader(
+        _ downloader: ImageDownloader,
+        didDownload image: KFCrossPlatformImage,
+        for url: URL,
+        with response: URLResponse?)
+
+    /// Checks if a received HTTP status code is valid or not.
+    /// By default, a status code in range 200..<400 is considered as valid.
+    /// If an invalid code is received, the downloader will raise an `KingfisherError` with
+    /// `ResponseErrorReason.invalidHTTPStatusCode` as its reason.
+    ///
+    /// - Parameters:
+    ///   - code: The received HTTP status code.
+    ///   - downloader: The `ImageDownloader` object asks for validate status code.
+    /// - Returns: Returns a value to indicate whether this HTTP status code is valid or not.
+    /// - Note: If the default 200 to 400 valid code does not suit your need,
+    ///         you can implement this method to change that behavior.
+    func isValidStatusCode(_ code: Int, for downloader: ImageDownloader) -> Bool
+
+    /// Called when the task has received a valid HTTP response after it passes other checks such as the status code.
+    /// You can perform additional checks or verification on the response to determine if the download should be allowed.
+    ///
+    /// For example, it is useful if you want to verify some header values in the response before actually starting the
+    /// download.
+    ///
+    /// If implemented, it is your responsibility to call the `completionHandler` with a proper response disposition,
+    /// such as `.allow` to start the actual downloading or `.cancel` to cancel the task. If `.cancel` is used as the
+    /// disposition, the downloader will raise an `KingfisherError` with
+    /// `ResponseErrorReason.cancelledByDelegate` as its reason. If not implemented, any response which passes other
+    /// checked will be allowed and the download starts.
+    ///
+    /// - Parameters:
+    ///   - downloader: The `ImageDownloader` object which is used for the downloading operation.
+    ///   - response: The original response object of the downloading process.
+    ///   - completionHandler: A completion handler that receives the disposition for the download task. You must call
+    ///   this handler with either `.allow` or `.cancel`.
+    func imageDownloader(
+        _ downloader: ImageDownloader,
+        didReceive response: URLResponse,
+        completionHandler: @escaping (URLSession.ResponseDisposition) -> Void)
+}
+
+// Default implementation for `ImageDownloaderDelegate`.
+extension ImageDownloaderDelegate {
+    public func imageDownloader(
+        _ downloader: ImageDownloader,
+        willDownloadImageForURL url: URL,
+        with request: URLRequest?) {}
+
+    public func imageDownloader(
+        _ downloader: ImageDownloader,
+        didFinishDownloadingImageForURL url: URL,
+        with response: URLResponse?,
+        error: Error?) {}
+
+    public func imageDownloader(
+        _ downloader: ImageDownloader,
+        didDownload image: KFCrossPlatformImage,
+        for url: URL,
+        with response: URLResponse?) {}
+
+    public func isValidStatusCode(_ code: Int, for downloader: ImageDownloader) -> Bool {
+        return (200..<400).contains(code)
+    }
+  
+    public func imageDownloader(_ downloader: ImageDownloader, didDownload data: Data, with task: SessionDataTask) -> Data? {
+        guard let url = task.originalURL else {
+            return data
+        }
+        return imageDownloader(downloader, didDownload: data, for: url)
+    }
+  
+    public func imageDownloader(_ downloader: ImageDownloader, didDownload data: Data, for url: URL) -> Data? {
+        return data
+    }
+
+    public func imageDownloader(
+        _ downloader: ImageDownloader,
+        didReceive response: URLResponse,
+        completionHandler: @escaping (URLSession.ResponseDisposition) -> Void) {
+            completionHandler(.allow)
+        }
+
+}

Pods/Kingfisher/Sources/Networking/ImageModifier.swift

@@ -0,0 +1,120 @@
+//
+//  ImageModifier.swift
+//  Kingfisher
+//
+//  Created by Ethan Gill on 2017/11/28.
+//
+//  Copyright (c) 2019 Ethan Gill <ethan.gill@me.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+/// An `ImageModifier` can be used to change properties on an image between cache serialization and the actual use of
+/// the image. The `modify(_:)` method will be called after the image retrieved from its source and before it returned
+/// to the caller. This modified image is expected to be only used for rendering purpose, any changes applied by the
+/// `ImageModifier` will not be serialized or cached.
+public protocol ImageModifier {
+    /// Modify an input `Image`.
+    ///
+    /// - parameter image:   Image which will be modified by `self`
+    ///
+    /// - returns: The modified image.
+    ///
+    /// - Note: The return value will be unmodified if modifying is not possible on
+    ///         the current platform.
+    /// - Note: Most modifiers support UIImage or NSImage, but not CGImage.
+    func modify(_ image: KFCrossPlatformImage) -> KFCrossPlatformImage
+}
+
+/// A wrapper for creating an `ImageModifier` easier.
+/// This type conforms to `ImageModifier` and wraps an image modify block.
+/// If the `block` throws an error, the original image will be used.
+public struct AnyImageModifier: ImageModifier {
+
+    /// A block which modifies images, or returns the original image
+    /// if modification cannot be performed with an error.
+    let block: (KFCrossPlatformImage) throws -> KFCrossPlatformImage
+
+    /// Creates an `AnyImageModifier` with a given `modify` block.
+    public init(modify: @escaping (KFCrossPlatformImage) throws -> KFCrossPlatformImage) {
+        block = modify
+    }
+
+    /// Modify an input `Image`. See `ImageModifier` protocol for more.
+    public func modify(_ image: KFCrossPlatformImage) -> KFCrossPlatformImage {
+        return (try? block(image)) ?? image
+    }
+}
+
+#if os(iOS) || os(tvOS) || os(watchOS) || os(visionOS)
+import UIKit
+
+/// Modifier for setting the rendering mode of images.
+public struct RenderingModeImageModifier: ImageModifier {
+
+    /// The rendering mode to apply to the image.
+    public let renderingMode: UIImage.RenderingMode
+
+    /// Creates a `RenderingModeImageModifier`.
+    ///
+    /// - Parameter renderingMode: The rendering mode to apply to the image. Default is `.automatic`.
+    public init(renderingMode: UIImage.RenderingMode = .automatic) {
+        self.renderingMode = renderingMode
+    }
+
+    /// Modify an input `Image`. See `ImageModifier` protocol for more.
+    public func modify(_ image: KFCrossPlatformImage) -> KFCrossPlatformImage {
+        return image.withRenderingMode(renderingMode)
+    }
+}
+
+/// Modifier for setting the `flipsForRightToLeftLayoutDirection` property of images.
+public struct FlipsForRightToLeftLayoutDirectionImageModifier: ImageModifier {
+
+    /// Creates a `FlipsForRightToLeftLayoutDirectionImageModifier`.
+    public init() {}
+
+    /// Modify an input `Image`. See `ImageModifier` protocol for more.
+    public func modify(_ image: KFCrossPlatformImage) -> KFCrossPlatformImage {
+        return image.imageFlippedForRightToLeftLayoutDirection()
+    }
+}
+
+/// Modifier for setting the `alignmentRectInsets` property of images.
+public struct AlignmentRectInsetsImageModifier: ImageModifier {
+
+    /// The alignment insets to apply to the image
+    public let alignmentInsets: UIEdgeInsets
+
+    /// Creates an `AlignmentRectInsetsImageModifier`.
+    public init(alignmentInsets: UIEdgeInsets) {
+        self.alignmentInsets = alignmentInsets
+    }
+
+    /// Modify an input `Image`. See `ImageModifier` protocol for more.
+    public func modify(_ image: KFCrossPlatformImage) -> KFCrossPlatformImage {
+        return image.withAlignmentRectInsets(alignmentInsets)
+    }
+}
+#endif

Pods/Kingfisher/Sources/Networking/ImagePrefetcher.swift

@@ -0,0 +1,442 @@
+//
+//  ImagePrefetcher.swift
+//  Kingfisher
+//
+//  Created by Claire Knight <claire.knight@moggytech.co.uk> on 24/02/2016
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+
+#if os(macOS)
+import AppKit
+#else
+import UIKit
+#endif
+
+/// Progress update block of prefetcher when initialized with a list of resources.
+///
+/// - `skippedResources`: An array of resources that are already cached before the prefetching starting.
+/// - `failedResources`: An array of resources that fail to be downloaded. It could because of being cancelled while
+///                      downloading, encountered an error when downloading or the download not being started at all.
+/// - `completedResources`: An array of resources that are downloaded and cached successfully.
+public typealias PrefetcherProgressBlock =
+    ((_ skippedResources: [Resource], _ failedResources: [Resource], _ completedResources: [Resource]) -> Void)
+
+/// Progress update block of prefetcher when initialized with a list of resources.
+///
+/// - `skippedSources`: An array of sources that are already cached before the prefetching starting.
+/// - `failedSources`: An array of sources that fail to be fetched.
+/// - `completedResources`: An array of sources that are fetched and cached successfully.
+public typealias PrefetcherSourceProgressBlock =
+    ((_ skippedSources: [Source], _ failedSources: [Source], _ completedSources: [Source]) -> Void)
+
+/// Completion block of prefetcher when initialized with a list of sources.
+///
+/// - `skippedResources`: An array of resources that are already cached before the prefetching starting.
+/// - `failedResources`: An array of resources that fail to be downloaded. It could because of being cancelled while
+///                      downloading, encountered an error when downloading or the download not being started at all.
+/// - `completedResources`: An array of resources that are downloaded and cached successfully.
+public typealias PrefetcherCompletionHandler =
+    ((_ skippedResources: [Resource], _ failedResources: [Resource], _ completedResources: [Resource]) -> Void)
+
+/// Completion block of prefetcher when initialized with a list of sources.
+///
+/// - `skippedSources`: An array of sources that are already cached before the prefetching starting.
+/// - `failedSources`: An array of sources that fail to be fetched.
+/// - `completedSources`: An array of sources that are fetched and cached successfully.
+public typealias PrefetcherSourceCompletionHandler =
+    ((_ skippedSources: [Source], _ failedSources: [Source], _ completedSources: [Source]) -> Void)
+
+/// `ImagePrefetcher` represents a downloading manager for requesting many images via URLs, then caching them.
+/// This is useful when you know a list of image resources and want to download them before showing. It also works with
+/// some Cocoa prefetching mechanism like table view or collection view `prefetchDataSource`, to start image downloading
+/// and caching before they display on screen.
+public class ImagePrefetcher: CustomStringConvertible {
+
+    public var description: String {
+        return "\(Unmanaged.passUnretained(self).toOpaque())"
+    }
+    
+    /// The maximum concurrent downloads to use when prefetching images. Default is 5.
+    public var maxConcurrentDownloads = 5
+
+    private let prefetchSources: [Source]
+    private let optionsInfo: KingfisherParsedOptionsInfo
+
+    private var progressBlock: PrefetcherProgressBlock?
+    private var completionHandler: PrefetcherCompletionHandler?
+
+    private var progressSourceBlock: PrefetcherSourceProgressBlock?
+    private var completionSourceHandler: PrefetcherSourceCompletionHandler?
+    
+    private var tasks = [String: DownloadTask.WrappedTask]()
+    
+    private var pendingSources: ArraySlice<Source>
+    private var skippedSources = [Source]()
+    private var completedSources = [Source]()
+    private var failedSources = [Source]()
+    
+    private var stopped = false
+    
+    // A manager used for prefetching. We will use the helper methods in manager.
+    private let manager: KingfisherManager
+
+    private let prefetchQueue = DispatchQueue(label: "com.onevcat.Kingfisher.ImagePrefetcher.prefetchQueue")
+    private static let requestingQueue = DispatchQueue(label: "com.onevcat.Kingfisher.ImagePrefetcher.requestingQueue")
+
+    private var finished: Bool {
+        let totalFinished: Int = failedSources.count + skippedSources.count + completedSources.count
+        return totalFinished == prefetchSources.count && tasks.isEmpty
+    }
+
+    /// Creates an image prefetcher with an array of URLs.
+    ///
+    /// The prefetcher should be initiated with a list of prefetching targets. The URLs list is immutable.
+    /// After you get a valid `ImagePrefetcher` object, you call `start()` on it to begin the prefetching process.
+    /// The images which are already cached will be skipped without downloading again.
+    ///
+    /// - Parameters:
+    ///   - urls: The URLs which should be prefetched.
+    ///   - options: Options could control some behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called every time an resource is downloaded, skipped or cancelled.
+    ///   - completionHandler: Called when the whole prefetching process finished.
+    ///
+    /// - Note:
+    /// By default, the `ImageDownloader.defaultDownloader` and `ImageCache.defaultCache` will be used as
+    /// the downloader and cache target respectively. You can specify another downloader or cache by using
+    /// a customized `KingfisherOptionsInfo`. Both the progress and completion block will be invoked in
+    /// main thread. The `.callbackQueue` value in `optionsInfo` will be ignored in this method.
+    public convenience init(
+        urls: [URL],
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: PrefetcherProgressBlock? = nil,
+        completionHandler: PrefetcherCompletionHandler? = nil)
+    {
+        let resources: [Resource] = urls.map { $0 }
+        self.init(
+            resources: resources,
+            options: options,
+            progressBlock: progressBlock,
+            completionHandler: completionHandler)
+    }
+
+    /// Creates an image prefetcher with an array of URLs.
+    ///
+    /// The prefetcher should be initiated with a list of prefetching targets. The URLs list is immutable.
+    /// After you get a valid `ImagePrefetcher` object, you call `start()` on it to begin the prefetching process.
+    /// The images which are already cached will be skipped without downloading again.
+    ///
+    /// - Parameters:
+    ///   - urls: The URLs which should be prefetched.
+    ///   - options: Options could control some behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - completionHandler: Called when the whole prefetching process finished.
+    ///
+    /// - Note:
+    /// By default, the `ImageDownloader.defaultDownloader` and `ImageCache.defaultCache` will be used as
+    /// the downloader and cache target respectively. You can specify another downloader or cache by using
+    /// a customized `KingfisherOptionsInfo`. Both the progress and completion block will be invoked in
+    /// main thread. The `.callbackQueue` value in `optionsInfo` will be ignored in this method.
+    public convenience init(
+        urls: [URL],
+        options: KingfisherOptionsInfo? = nil,
+        completionHandler: PrefetcherCompletionHandler? = nil)
+    {
+        let resources: [Resource] = urls.map { $0 }
+        self.init(
+            resources: resources,
+            options: options,
+            progressBlock: nil,
+            completionHandler: completionHandler)
+    }
+
+    /// Creates an image prefetcher with an array of resources.
+    ///
+    /// - Parameters:
+    ///   - resources: The resources which should be prefetched. See `Resource` type for more.
+    ///   - options: Options could control some behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called every time an resource is downloaded, skipped or cancelled.
+    ///   - completionHandler: Called when the whole prefetching process finished.
+    ///
+    /// - Note:
+    /// By default, the `ImageDownloader.defaultDownloader` and `ImageCache.defaultCache` will be used as
+    /// the downloader and cache target respectively. You can specify another downloader or cache by using
+    /// a customized `KingfisherOptionsInfo`. Both the progress and completion block will be invoked in
+    /// main thread. The `.callbackQueue` value in `optionsInfo` will be ignored in this method.
+    public convenience init(
+        resources: [Resource],
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: PrefetcherProgressBlock? = nil,
+        completionHandler: PrefetcherCompletionHandler? = nil)
+    {
+        self.init(sources: resources.map { $0.convertToSource() }, options: options)
+        self.progressBlock = progressBlock
+        self.completionHandler = completionHandler
+    }
+
+    /// Creates an image prefetcher with an array of resources.
+    ///
+    /// - Parameters:
+    ///   - resources: The resources which should be prefetched. See `Resource` type for more.
+    ///   - options: Options could control some behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - completionHandler: Called when the whole prefetching process finished.
+    ///
+    /// - Note:
+    /// By default, the `ImageDownloader.defaultDownloader` and `ImageCache.defaultCache` will be used as
+    /// the downloader and cache target respectively. You can specify another downloader or cache by using
+    /// a customized `KingfisherOptionsInfo`. Both the progress and completion block will be invoked in
+    /// main thread. The `.callbackQueue` value in `optionsInfo` will be ignored in this method.
+    public convenience init(
+        resources: [Resource],
+        options: KingfisherOptionsInfo? = nil,
+        completionHandler: PrefetcherCompletionHandler? = nil)
+    {
+        self.init(sources: resources.map { $0.convertToSource() }, options: options)
+        self.completionHandler = completionHandler
+    }
+
+    /// Creates an image prefetcher with an array of sources.
+    ///
+    /// - Parameters:
+    ///   - sources: The sources which should be prefetched. See `Source` type for more.
+    ///   - options: Options could control some behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - progressBlock: Called every time an source fetching successes, fails, is skipped.
+    ///   - completionHandler: Called when the whole prefetching process finished.
+    ///
+    /// - Note:
+    /// By default, the `ImageDownloader.defaultDownloader` and `ImageCache.defaultCache` will be used as
+    /// the downloader and cache target respectively. You can specify another downloader or cache by using
+    /// a customized `KingfisherOptionsInfo`. Both the progress and completion block will be invoked in
+    /// main thread. The `.callbackQueue` value in `optionsInfo` will be ignored in this method.
+    public convenience init(sources: [Source],
+        options: KingfisherOptionsInfo? = nil,
+        progressBlock: PrefetcherSourceProgressBlock? = nil,
+        completionHandler: PrefetcherSourceCompletionHandler? = nil)
+    {
+        self.init(sources: sources, options: options)
+        self.progressSourceBlock = progressBlock
+        self.completionSourceHandler = completionHandler
+    }
+
+    /// Creates an image prefetcher with an array of sources.
+    ///
+    /// - Parameters:
+    ///   - sources: The sources which should be prefetched. See `Source` type for more.
+    ///   - options: Options could control some behaviors. See `KingfisherOptionsInfo` for more.
+    ///   - completionHandler: Called when the whole prefetching process finished.
+    ///
+    /// - Note:
+    /// By default, the `ImageDownloader.defaultDownloader` and `ImageCache.defaultCache` will be used as
+    /// the downloader and cache target respectively. You can specify another downloader or cache by using
+    /// a customized `KingfisherOptionsInfo`. Both the progress and completion block will be invoked in
+    /// main thread. The `.callbackQueue` value in `optionsInfo` will be ignored in this method.
+    public convenience init(sources: [Source],
+        options: KingfisherOptionsInfo? = nil,
+        completionHandler: PrefetcherSourceCompletionHandler? = nil)
+    {
+        self.init(sources: sources, options: options)
+        self.completionSourceHandler = completionHandler
+    }
+
+    init(sources: [Source], options: KingfisherOptionsInfo?) {
+        var options = KingfisherParsedOptionsInfo(options)
+        prefetchSources = sources
+        pendingSources = ArraySlice(sources)
+
+        // We want all callbacks from our prefetch queue, so we should ignore the callback queue in options.
+        // Add our own callback dispatch queue to make sure all internal callbacks are
+        // coming back in our expected queue.
+        options.callbackQueue = .dispatch(prefetchQueue)
+        optionsInfo = options
+
+        let cache = optionsInfo.targetCache ?? .default
+        let downloader = optionsInfo.downloader ?? .default
+        manager = KingfisherManager(downloader: downloader, cache: cache)
+    }
+
+    /// Starts to download the resources and cache them. This can be useful for background downloading
+    /// of assets that are required for later use in an app. This code will not try and update any UI
+    /// with the results of the process.
+    public func start() {
+        prefetchQueue.async {
+            guard !self.stopped else {
+                assertionFailure("You can not restart the same prefetcher. Try to create a new prefetcher.")
+                self.handleComplete()
+                return
+            }
+
+            guard self.maxConcurrentDownloads > 0 else {
+                assertionFailure("There should be concurrent downloads value should be at least 1.")
+                self.handleComplete()
+                return
+            }
+
+            // Empty case.
+            guard self.prefetchSources.count > 0 else {
+                self.handleComplete()
+                return
+            }
+
+            let initialConcurrentDownloads = min(self.prefetchSources.count, self.maxConcurrentDownloads)
+            for _ in 0 ..< initialConcurrentDownloads {
+                if let resource = self.pendingSources.popFirst() {
+                    self.startPrefetching(resource)
+                }
+            }
+        }
+    }
+
+    /// Stops current downloading progress, and cancel any future prefetching activity that might be occuring.
+    public func stop() {
+        prefetchQueue.async {
+            if self.finished { return }
+            self.stopped = true
+            self.tasks.values.forEach { $0.cancel() }
+        }
+    }
+    
+    private func downloadAndCache(_ source: Source) {
+
+        let downloadTaskCompletionHandler: ((Result<RetrieveImageResult, KingfisherError>) -> Void) = { result in
+            self.tasks.removeValue(forKey: source.cacheKey)
+            do {
+                let _ = try result.get()
+                self.completedSources.append(source)
+            } catch {
+                self.failedSources.append(source)
+            }
+            
+            self.reportProgress()
+            if self.stopped {
+                if self.tasks.isEmpty {
+                    self.failedSources.append(contentsOf: self.pendingSources)
+                    self.handleComplete()
+                }
+            } else {
+                self.reportCompletionOrStartNext()
+            }
+        }
+
+        var downloadTask: DownloadTask.WrappedTask?
+        ImagePrefetcher.requestingQueue.sync {
+            let context = RetrievingContext(
+                options: optionsInfo, originalSource: source
+            )
+            downloadTask = manager.loadAndCacheImage(
+                source: source,
+                context: context,
+                completionHandler: downloadTaskCompletionHandler)
+        }
+
+        if let downloadTask = downloadTask {
+            tasks[source.cacheKey] = downloadTask
+        }
+    }
+    
+    private func append(cached source: Source) {
+        skippedSources.append(source)
+ 
+        reportProgress()
+        reportCompletionOrStartNext()
+    }
+    
+    private func startPrefetching(_ source: Source)
+    {
+        if optionsInfo.forceRefresh {
+            downloadAndCache(source)
+            return
+        }
+        
+        let cacheType = manager.cache.imageCachedType(
+            forKey: source.cacheKey,
+            processorIdentifier: optionsInfo.processor.identifier)
+        switch cacheType {
+        case .memory:
+            append(cached: source)
+        case .disk:
+            if optionsInfo.alsoPrefetchToMemory {
+                let context = RetrievingContext(options: optionsInfo, originalSource: source)
+                _ = manager.retrieveImageFromCache(
+                    source: source,
+                    context: context)
+                {
+                    _ in
+                    self.append(cached: source)
+                }
+            } else {
+                append(cached: source)
+            }
+        case .none:
+            downloadAndCache(source)
+        }
+    }
+    
+    private func reportProgress() {
+
+        if progressBlock == nil && progressSourceBlock == nil {
+            return
+        }
+
+        let skipped = self.skippedSources
+        let failed = self.failedSources
+        let completed = self.completedSources
+        CallbackQueue.mainCurrentOrAsync.execute {
+            self.progressSourceBlock?(skipped, failed, completed)
+            self.progressBlock?(
+                skipped.compactMap { $0.asResource },
+                failed.compactMap { $0.asResource },
+                completed.compactMap { $0.asResource }
+            )
+        }
+    }
+    
+    private func reportCompletionOrStartNext() {
+        if let resource = self.pendingSources.popFirst() {
+            // Loose call stack for huge ammount of sources.
+            prefetchQueue.async { self.startPrefetching(resource) }
+        } else {
+            guard allFinished else { return }
+            self.handleComplete()
+        }
+    }
+
+    var allFinished: Bool {
+        return skippedSources.count + failedSources.count + completedSources.count == prefetchSources.count
+    }
+    
+    private func handleComplete() {
+
+        if completionHandler == nil && completionSourceHandler == nil {
+            return
+        }
+        
+        // The completion handler should be called on the main thread
+        CallbackQueue.mainCurrentOrAsync.execute {
+            self.completionSourceHandler?(self.skippedSources, self.failedSources, self.completedSources)
+            self.completionHandler?(
+                self.skippedSources.compactMap { $0.asResource },
+                self.failedSources.compactMap { $0.asResource },
+                self.completedSources.compactMap { $0.asResource }
+            )
+            self.completionHandler = nil
+            self.progressBlock = nil
+        }
+    }
+}

Pods/Kingfisher/Sources/Networking/RedirectHandler.swift

@@ -0,0 +1,76 @@
+//
+//  RedirectHandler.swift
+//  Kingfisher
+//
+//  Created by Roman Maidanovych on 2018/12/10.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+/// Represents and wraps a method for modifying request during an image download request redirection.
+public protocol ImageDownloadRedirectHandler {
+
+    /// The `ImageDownloadRedirectHandler` contained will be used to change the request before redirection.
+    /// This is the posibility you can modify the image download request during redirection. You can modify the
+    /// request for some customizing purpose, such as adding auth token to the header, do basic HTTP auth or
+    /// something like url mapping.
+    ///
+    /// Usually, you pass an `ImageDownloadRedirectHandler` as the associated value of
+    /// `KingfisherOptionsInfoItem.redirectHandler` and use it as the `options` parameter in related methods.
+    ///
+    /// If you do nothing with the input `request` and return it as is, a downloading process will redirect with it.
+    ///
+    /// - Parameters:
+    ///   - task: The current `SessionDataTask` which triggers this redirect.
+    ///   - response: The response received during redirection.
+    ///   - newRequest: The request for redirection which can be modified.
+    ///   - completionHandler: A closure for being called with modified request.
+    func handleHTTPRedirection(
+        for task: SessionDataTask,
+        response: HTTPURLResponse,
+        newRequest: URLRequest,
+        completionHandler: @escaping (URLRequest?) -> Void)
+}
+
+/// A wrapper for creating an `ImageDownloadRedirectHandler` easier.
+/// This type conforms to `ImageDownloadRedirectHandler` and wraps a redirect request modify block.
+public struct AnyRedirectHandler: ImageDownloadRedirectHandler {
+    
+    let block: (SessionDataTask, HTTPURLResponse, URLRequest, @escaping (URLRequest?) -> Void) -> Void
+
+    public func handleHTTPRedirection(
+        for task: SessionDataTask,
+        response: HTTPURLResponse,
+        newRequest: URLRequest,
+        completionHandler: @escaping (URLRequest?) -> Void)
+    {
+        block(task, response, newRequest, completionHandler)
+    }
+    
+    /// Creates a value of `ImageDownloadRedirectHandler` which runs `modify` block.
+    ///
+    /// - Parameter modify: The request modifying block runs when a request modifying task comes.
+    ///
+    public init(handle: @escaping (SessionDataTask, HTTPURLResponse, URLRequest, @escaping (URLRequest?) -> Void) -> Void) {
+        block = handle
+    }
+}

Pods/Kingfisher/Sources/Networking/RequestModifier.swift

@@ -0,0 +1,108 @@
+//
+//  RequestModifier.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2016/09/05.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+/// Represents and wraps a method for modifying request before an image download request starts in an asynchronous way.
+public protocol AsyncImageDownloadRequestModifier {
+
+    /// This method will be called just before the `request` being sent.
+    /// This is the last chance you can modify the image download request. You can modify the request for some
+    /// customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url mapping.
+    /// When you have done with the modification, call the `reportModified` block with the modified request and the data
+    /// download will happen with this request.
+    ///
+    /// Usually, you pass an `AsyncImageDownloadRequestModifier` as the associated value of
+    /// `KingfisherOptionsInfoItem.requestModifier` and use it as the `options` parameter in related methods.
+    ///
+    /// If you do nothing with the input `request` and return it as is, a downloading process will start with it.
+    ///
+    /// - Parameters:
+    ///   - request: The input request contains necessary information like `url`. This request is generated
+    ///              according to your resource url as a GET request.
+    ///   - reportModified: The callback block you need to call after the asynchronous modifying done.
+    ///
+    func modified(for request: URLRequest, reportModified: @escaping (URLRequest?) -> Void)
+
+    /// A block will be called when the download task started.
+    ///
+    /// If an `AsyncImageDownloadRequestModifier` and the asynchronous modification happens before the download, the
+    /// related download method will not return a valid `DownloadTask` value. Instead, you can get one from this method.
+    var onDownloadTaskStarted: ((DownloadTask?) -> Void)? { get }
+}
+
+/// Represents and wraps a method for modifying request before an image download request starts.
+public protocol ImageDownloadRequestModifier: AsyncImageDownloadRequestModifier {
+
+    /// This method will be called just before the `request` being sent.
+    /// This is the last chance you can modify the image download request. You can modify the request for some
+    /// customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url mapping.
+    ///
+    /// Usually, you pass an `ImageDownloadRequestModifier` as the associated value of
+    /// `KingfisherOptionsInfoItem.requestModifier` and use it as the `options` parameter in related methods.
+    ///
+    /// If you do nothing with the input `request` and return it as is, a downloading process will start with it.
+    ///
+    /// - Parameter request: The input request contains necessary information like `url`. This request is generated
+    ///                      according to your resource url as a GET request.
+    /// - Returns: A modified version of request, which you wish to use for downloading an image. If `nil` returned,
+    ///            a `KingfisherError.requestError` with `.emptyRequest` as its reason will occur.
+    ///
+    func modified(for request: URLRequest) -> URLRequest?
+}
+
+extension ImageDownloadRequestModifier {
+    public func modified(for request: URLRequest, reportModified: @escaping (URLRequest?) -> Void) {
+        let request = modified(for: request)
+        reportModified(request)
+    }
+
+    /// This is `nil` for a sync `ImageDownloadRequestModifier` by default. You can get the `DownloadTask` from the
+    /// return value of downloader method.
+    public var onDownloadTaskStarted: ((DownloadTask?) -> Void)? { return nil }
+}
+
+/// A wrapper for creating an `ImageDownloadRequestModifier` easier.
+/// This type conforms to `ImageDownloadRequestModifier` and wraps an image modify block.
+public struct AnyModifier: ImageDownloadRequestModifier {
+    
+    let block: (URLRequest) -> URLRequest?
+
+    /// For `ImageDownloadRequestModifier` conformation.
+    public func modified(for request: URLRequest) -> URLRequest? {
+        return block(request)
+    }
+    
+    /// Creates a value of `ImageDownloadRequestModifier` which runs `modify` block.
+    ///
+    /// - Parameter modify: The request modifying block runs when a request modifying task comes.
+    ///                     The return `URLRequest?` value of this block will be used as the image download request.
+    ///                     If `nil` returned, a `KingfisherError.requestError` with `.emptyRequest` as its
+    ///                     reason will occur.
+    public init(modify: @escaping (URLRequest) -> URLRequest?) {
+        block = modify
+    }
+}

Pods/Kingfisher/Sources/Networking/RetryStrategy.swift

@@ -0,0 +1,153 @@
+//
+//  RetryStrategy.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2020/05/04.
+//
+//  Copyright (c) 2020 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+/// Represents a retry context which could be used to determine the current retry status.
+public class RetryContext {
+
+    /// The source from which the target image should be retrieved.
+    public let source: Source
+
+    /// The last error which caused current retry behavior.
+    public let error: KingfisherError
+
+    /// The retried count before current retry happens. This value is `0` if the current retry is for the first time.
+    public var retriedCount: Int
+
+    /// A user set value for passing any other information during the retry. If you choose to use `RetryDecision.retry`
+    /// as the retry decision for `RetryStrategy.retry(context:retryHandler:)`, the associated value of
+    /// `RetryDecision.retry` will be delivered to you in the next retry.
+    public internal(set) var userInfo: Any? = nil
+
+    init(source: Source, error: KingfisherError) {
+        self.source = source
+        self.error = error
+        self.retriedCount = 0
+    }
+
+    @discardableResult
+    func increaseRetryCount() -> RetryContext {
+        retriedCount += 1
+        return self
+    }
+}
+
+/// Represents decision of behavior on the current retry.
+public enum RetryDecision {
+    /// A retry should happen. The associated `userInfo` will be pass to the next retry in the `RetryContext` parameter.
+    case retry(userInfo: Any?)
+    /// There should be no more retry attempt. The image retrieving process will fail with an error.
+    case stop
+}
+
+/// Defines a retry strategy can be applied to a `.retryStrategy` option.
+public protocol RetryStrategy {
+
+    /// Kingfisher calls this method if an error happens during the image retrieving process from a `KingfisherManager`.
+    /// You implement this method to provide necessary logic based on the `context` parameter. Then you need to call
+    /// `retryHandler` to pass the retry decision back to Kingfisher.
+    ///
+    /// - Parameters:
+    ///   - context: The retry context containing information of current retry attempt.
+    ///   - retryHandler: A block you need to call with a decision of whether the retry should happen or not.
+    func retry(context: RetryContext, retryHandler: @escaping (RetryDecision) -> Void)
+}
+
+/// A retry strategy that guides Kingfisher to retry when a `.responseError` happens, with a specified max retry count
+/// and a certain interval mechanism.
+public struct DelayRetryStrategy: RetryStrategy {
+
+    /// Represents the interval mechanism which used in a `DelayRetryStrategy`.
+    public enum Interval {
+        /// The next retry attempt should happen in fixed seconds. For example, if the associated value is 3, the
+        /// attempts happens after 3 seconds after the previous decision is made.
+        case seconds(TimeInterval)
+        /// The next retry attempt should happen in an accumulated duration. For example, if the associated value is 3,
+        /// the attempts happens with interval of 3, 6, 9, 12, ... seconds.
+        case accumulated(TimeInterval)
+        /// Uses a block to determine the next interval. The current retry count is given as a parameter.
+        case custom(block: (_ retriedCount: Int) -> TimeInterval)
+
+        func timeInterval(for retriedCount: Int) -> TimeInterval {
+            let retryAfter: TimeInterval
+            switch self {
+            case .seconds(let interval):
+                retryAfter = interval
+            case .accumulated(let interval):
+                retryAfter = Double(retriedCount + 1) * interval
+            case .custom(let block):
+                retryAfter = block(retriedCount)
+            }
+            return retryAfter
+        }
+    }
+
+    /// The max retry count defined for the retry strategy
+    public let maxRetryCount: Int
+
+    /// The retry interval mechanism defined for the retry strategy.
+    public let retryInterval: Interval
+
+    /// Creates a delay retry strategy.
+    /// - Parameters:
+    ///   - maxRetryCount: The max retry count.
+    ///   - retryInterval: The retry interval mechanism. By default, `.seconds(3)` is used to provide a constant retry
+    ///   interval.
+    public init(maxRetryCount: Int, retryInterval: Interval = .seconds(3)) {
+        self.maxRetryCount = maxRetryCount
+        self.retryInterval = retryInterval
+    }
+
+    public func retry(context: RetryContext, retryHandler: @escaping (RetryDecision) -> Void) {
+        // Retry count exceeded.
+        guard context.retriedCount < maxRetryCount else {
+            retryHandler(.stop)
+            return
+        }
+
+        // User cancel the task. No retry.
+        guard !context.error.isTaskCancelled else {
+            retryHandler(.stop)
+            return
+        }
+
+        // Only retry for a response error.
+        guard case KingfisherError.responseError = context.error else {
+            retryHandler(.stop)
+            return
+        }
+
+        let interval = retryInterval.timeInterval(for: context.retriedCount)
+        if interval == 0 {
+            retryHandler(.retry(userInfo: nil))
+        } else {
+            DispatchQueue.main.asyncAfter(deadline: .now() + interval) {
+                retryHandler(.retry(userInfo: nil))
+            }
+        }
+    }
+}

Pods/Kingfisher/Sources/Networking/SessionDataTask.swift

@@ -0,0 +1,127 @@
+//
+//  SessionDataTask.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2018/11/1.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+/// Represents a session data task in `ImageDownloader`. It consists of an underlying `URLSessionDataTask` and
+/// an array of `TaskCallback`. Multiple `TaskCallback`s could be added for a single downloading data task.
+public class SessionDataTask {
+
+    /// Represents the type of token which used for cancelling a task.
+    public typealias CancelToken = Int
+
+    struct TaskCallback {
+        let onCompleted: Delegate<Result<ImageLoadingResult, KingfisherError>, Void>?
+        let options: KingfisherParsedOptionsInfo
+    }
+
+    /// Downloaded raw data of current task.
+    public private(set) var mutableData: Data
+
+    // This is a copy of `task.originalRequest?.url`. It is for getting a race-safe behavior for a pitfall on iOS 13.
+    // Ref: https://github.com/onevcat/Kingfisher/issues/1511
+    public let originalURL: URL?
+
+    /// The underlying download task. It is only for debugging purpose when you encountered an error. You should not
+    /// modify the content of this task or start it yourself.
+    public let task: URLSessionDataTask
+    private var callbacksStore = [CancelToken: TaskCallback]()
+
+    var callbacks: [SessionDataTask.TaskCallback] {
+        lock.lock()
+        defer { lock.unlock() }
+        return Array(callbacksStore.values)
+    }
+
+    private var currentToken = 0
+    private let lock = NSLock()
+
+    let onTaskDone = Delegate<(Result<(Data, URLResponse?), KingfisherError>, [TaskCallback]), Void>()
+    let onCallbackCancelled = Delegate<(CancelToken, TaskCallback), Void>()
+
+    var started = false
+    var containsCallbacks: Bool {
+        // We should be able to use `task.state != .running` to check it.
+        // However, in some rare cases, cancelling the task does not change
+        // task state to `.cancelling` immediately, but still in `.running`.
+        // So we need to check callbacks count to for sure that it is safe to remove the
+        // task in delegate.
+        return !callbacks.isEmpty
+    }
+
+    init(task: URLSessionDataTask) {
+        self.task = task
+        self.originalURL = task.originalRequest?.url
+        mutableData = Data()
+    }
+
+    func addCallback(_ callback: TaskCallback) -> CancelToken {
+        lock.lock()
+        defer { lock.unlock() }
+        callbacksStore[currentToken] = callback
+        defer { currentToken += 1 }
+        return currentToken
+    }
+
+    func removeCallback(_ token: CancelToken) -> TaskCallback? {
+        lock.lock()
+        defer { lock.unlock() }
+        if let callback = callbacksStore[token] {
+            callbacksStore[token] = nil
+            return callback
+        }
+        return nil
+    }
+    
+    func removeAllCallbacks() -> Void {
+        lock.lock()
+        defer { lock.unlock() }
+        callbacksStore.removeAll()
+    }
+
+    func resume() {
+        guard !started else { return }
+        started = true
+        task.resume()
+    }
+
+    func cancel(token: CancelToken) {
+        guard let callback = removeCallback(token) else {
+            return
+        }
+        onCallbackCancelled.call((token, callback))
+    }
+
+    func forceCancel() {
+        for token in callbacksStore.keys {
+            cancel(token: token)
+        }
+    }
+
+    func didReceiveData(_ data: Data) {
+        mutableData.append(data)
+    }
+}

Pods/Kingfisher/Sources/Networking/SessionDelegate.swift

@@ -0,0 +1,271 @@
+//
+//  SessionDelegate.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2018/11/1.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+// Represents the delegate object of downloader session. It also behave like a task manager for downloading.
+@objc(KFSessionDelegate) // Fix for ObjC header name conflicting. https://github.com/onevcat/Kingfisher/issues/1530
+open class SessionDelegate: NSObject {
+
+    typealias SessionChallengeFunc = (
+        URLSession,
+        URLAuthenticationChallenge,
+        (URLSession.AuthChallengeDisposition, URLCredential?) -> Void
+    )
+
+    typealias SessionTaskChallengeFunc = (
+        URLSession,
+        URLSessionTask,
+        URLAuthenticationChallenge,
+        (URLSession.AuthChallengeDisposition, URLCredential?) -> Void
+    )
+
+    private var tasks: [URL: SessionDataTask] = [:]
+    private let lock = NSLock()
+
+    let onValidStatusCode = Delegate<Int, Bool>()
+    let onResponseReceived = Delegate<(URLResponse, (URLSession.ResponseDisposition) -> Void), Void>()
+    let onDownloadingFinished = Delegate<(URL, Result<URLResponse, KingfisherError>), Void>()
+    let onDidDownloadData = Delegate<SessionDataTask, Data?>()
+
+    let onReceiveSessionChallenge = Delegate<SessionChallengeFunc, Void>()
+    let onReceiveSessionTaskChallenge = Delegate<SessionTaskChallengeFunc, Void>()
+
+    func add(
+        _ dataTask: URLSessionDataTask,
+        url: URL,
+        callback: SessionDataTask.TaskCallback) -> DownloadTask
+    {
+        lock.lock()
+        defer { lock.unlock() }
+
+        // Create a new task if necessary.
+        let task = SessionDataTask(task: dataTask)
+        task.onCallbackCancelled.delegate(on: self) { [weak task] (self, value) in
+            guard let task = task else { return }
+
+            let (token, callback) = value
+
+            let error = KingfisherError.requestError(reason: .taskCancelled(task: task, token: token))
+            task.onTaskDone.call((.failure(error), [callback]))
+            // No other callbacks waiting, we can clear the task now.
+            if !task.containsCallbacks {
+                let dataTask = task.task
+
+                self.cancelTask(dataTask)
+                self.remove(task)
+            }
+        }
+        let token = task.addCallback(callback)
+        tasks[url] = task
+        return DownloadTask(sessionTask: task, cancelToken: token)
+    }
+
+    private func cancelTask(_ dataTask: URLSessionDataTask) {
+        lock.lock()
+        defer { lock.unlock() }
+        dataTask.cancel()
+    }
+
+    func append(
+        _ task: SessionDataTask,
+        callback: SessionDataTask.TaskCallback) -> DownloadTask
+    {
+        let token = task.addCallback(callback)
+        return DownloadTask(sessionTask: task, cancelToken: token)
+    }
+
+    private func remove(_ task: SessionDataTask) {
+        lock.lock()
+        defer { lock.unlock() }
+
+        guard let url = task.originalURL else {
+            return
+        }
+        task.removeAllCallbacks()
+        tasks[url] = nil
+    }
+
+    private func task(for task: URLSessionTask) -> SessionDataTask? {
+        lock.lock()
+        defer { lock.unlock() }
+
+        guard let url = task.originalRequest?.url else {
+            return nil
+        }
+        guard let sessionTask = tasks[url] else {
+            return nil
+        }
+        guard sessionTask.task.taskIdentifier == task.taskIdentifier else {
+            return nil
+        }
+        return sessionTask
+    }
+
+    func task(for url: URL) -> SessionDataTask? {
+        lock.lock()
+        defer { lock.unlock() }
+        return tasks[url]
+    }
+
+    func cancelAll() {
+        lock.lock()
+        let taskValues = tasks.values
+        lock.unlock()
+        for task in taskValues {
+            task.forceCancel()
+        }
+    }
+
+    func cancel(url: URL) {
+        lock.lock()
+        let task = tasks[url]
+        lock.unlock()
+        task?.forceCancel()
+    }
+}
+
+extension SessionDelegate: URLSessionDataDelegate {
+
+    open func urlSession(
+        _ session: URLSession,
+        dataTask: URLSessionDataTask,
+        didReceive response: URLResponse,
+        completionHandler: @escaping (URLSession.ResponseDisposition) -> Void)
+    {
+        guard let httpResponse = response as? HTTPURLResponse else {
+            let error = KingfisherError.responseError(reason: .invalidURLResponse(response: response))
+            onCompleted(task: dataTask, result: .failure(error))
+            completionHandler(.cancel)
+            return
+        }
+
+        let httpStatusCode = httpResponse.statusCode
+        guard onValidStatusCode.call(httpStatusCode) == true else {
+            let error = KingfisherError.responseError(reason: .invalidHTTPStatusCode(response: httpResponse))
+            onCompleted(task: dataTask, result: .failure(error))
+            completionHandler(.cancel)
+            return
+        }
+
+        let inspectedHandler: (URLSession.ResponseDisposition) -> Void = { disposition in
+            if disposition == .cancel {
+                let error = KingfisherError.responseError(reason: .cancelledByDelegate(response: response))
+                self.onCompleted(task: dataTask, result: .failure(error))
+            }
+            completionHandler(disposition)
+        }
+        onResponseReceived.call((response, inspectedHandler))
+    }
+
+    open func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
+        guard let task = self.task(for: dataTask) else {
+            return
+        }
+        
+        task.didReceiveData(data)
+        
+        task.callbacks.forEach { callback in
+            callback.options.onDataReceived?.forEach { sideEffect in
+                sideEffect.onDataReceived(session, task: task, data: data)
+            }
+        }
+    }
+
+    open func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
+        guard let sessionTask = self.task(for: task) else { return }
+
+        if let url = sessionTask.originalURL {
+            let result: Result<URLResponse, KingfisherError>
+            if let error = error {
+                result = .failure(KingfisherError.responseError(reason: .URLSessionError(error: error)))
+            } else if let response = task.response {
+                result = .success(response)
+            } else {
+                result = .failure(KingfisherError.responseError(reason: .noURLResponse(task: sessionTask)))
+            }
+            onDownloadingFinished.call((url, result))
+        }
+
+        let result: Result<(Data, URLResponse?), KingfisherError>
+        if let error = error {
+            result = .failure(KingfisherError.responseError(reason: .URLSessionError(error: error)))
+        } else {
+            if let data = onDidDownloadData.call(sessionTask) {
+                result = .success((data, task.response))
+            } else {
+                result = .failure(KingfisherError.responseError(reason: .dataModifyingFailed(task: sessionTask)))
+            }
+        }
+        onCompleted(task: task, result: result)
+    }
+
+    open func urlSession(
+        _ session: URLSession,
+        didReceive challenge: URLAuthenticationChallenge,
+        completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void)
+    {
+        onReceiveSessionChallenge.call((session, challenge, completionHandler))
+    }
+
+    open func urlSession(
+        _ session: URLSession,
+        task: URLSessionTask,
+        didReceive challenge: URLAuthenticationChallenge,
+        completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void)
+    {
+        onReceiveSessionTaskChallenge.call((session, task, challenge, completionHandler))
+    }
+    
+    open func urlSession(
+        _ session: URLSession,
+        task: URLSessionTask,
+        willPerformHTTPRedirection response: HTTPURLResponse,
+        newRequest request: URLRequest,
+        completionHandler: @escaping (URLRequest?) -> Void)
+    {
+        guard let sessionDataTask = self.task(for: task),
+              let redirectHandler = Array(sessionDataTask.callbacks).last?.options.redirectHandler else
+        {
+            completionHandler(request)
+            return
+        }
+        
+        redirectHandler.handleHTTPRedirection(
+            for: sessionDataTask,
+            response: response,
+            newRequest: request,
+            completionHandler: completionHandler)
+    }
+
+    private func onCompleted(task: URLSessionTask, result: Result<(Data, URLResponse?), KingfisherError>) {
+        guard let sessionTask = self.task(for: task) else {
+            return
+        }
+        sessionTask.onTaskDone.call((result, sessionTask.callbacks))
+        remove(sessionTask)
+    }
+}

Pods/Kingfisher/Sources/PrivacyInfo.xcprivacy

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+    <key>NSPrivacyAccessedAPITypes</key>
+    <array>
+        <dict>
+            <key>NSPrivacyAccessedAPIType</key>
+            <string>NSPrivacyAccessedAPICategoryFileTimestamp</string>
+            <key>NSPrivacyAccessedAPITypeReasons</key>
+            <array>
+                <string>C617.1</string>
+            </array>
+        </dict>
+    </array>
+    <key>NSPrivacyTracking</key>
+    <false/>
+  <key>NSPrivacyTrackingDomains</key>
+  <array>
+  </array>
+  <key>NSPrivacyCollectedDataTypes</key>
+  <array>
+  </array>
+</dict>
+</plist>

Pods/Kingfisher/Sources/SwiftUI/ImageBinder.swift

@@ -0,0 +1,149 @@
+//
+//  ImageBinder.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2019/06/27.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if canImport(SwiftUI) && canImport(Combine)
+import SwiftUI
+import Combine
+
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+extension KFImage {
+
+    /// Represents a binder for `KFImage`. It takes responsibility as an `ObjectBinding` and performs
+    /// image downloading and progress reporting based on `KingfisherManager`.
+    class ImageBinder: ObservableObject {
+        
+        init() {}
+
+        var downloadTask: DownloadTask?
+        private var loading = false
+
+        var loadingOrSucceeded: Bool {
+            return loading || loadedImage != nil
+        }
+
+        // Do not use @Published due to https://github.com/onevcat/Kingfisher/issues/1717. Revert to @Published once
+        // we can drop iOS 12.
+        private(set) var loaded = false
+
+        private(set) var animating = false
+
+        var loadedImage: KFCrossPlatformImage? = nil { willSet { objectWillChange.send() } }
+        var progress: Progress = .init()
+
+        func markLoading() {
+            loading = true
+        }
+
+        func markLoaded(sendChangeEvent: Bool) {
+            loaded = true
+            if sendChangeEvent {
+                objectWillChange.send()
+            }
+        }
+
+        func start<HoldingView: KFImageHoldingView>(context: Context<HoldingView>) {
+            guard let source = context.source else {
+                CallbackQueue.mainCurrentOrAsync.execute {
+                    context.onFailureDelegate.call(KingfisherError.imageSettingError(reason: .emptySource))
+                    if let image = context.options.onFailureImage {
+                        self.loadedImage = image
+                    }
+                    self.loading = false
+                    self.markLoaded(sendChangeEvent: false)
+                }
+                return
+            }
+
+            loading = true
+            
+            progress = .init()
+            downloadTask = KingfisherManager.shared
+                .retrieveImage(
+                    with: source,
+                    options: context.options,
+                    progressBlock: { size, total in
+                        self.updateProgress(downloaded: size, total: total)
+                        context.onProgressDelegate.call((size, total))
+                    },
+                    completionHandler: { [weak self] result in
+
+                        guard let self = self else { return }
+
+                        CallbackQueue.mainCurrentOrAsync.execute {
+                            self.downloadTask = nil
+                            self.loading = false
+                        }
+                        
+                        switch result {
+                        case .success(let value):
+                            CallbackQueue.mainCurrentOrAsync.execute {
+                                if let fadeDuration = context.fadeTransitionDuration(cacheType: value.cacheType) {
+                                    self.animating = true
+                                    let animation = Animation.linear(duration: fadeDuration)
+                                    withAnimation(animation) {
+                                        // Trigger the view render to apply the animation.
+                                        self.markLoaded(sendChangeEvent: true)
+                                    }
+                                } else {
+                                    self.markLoaded(sendChangeEvent: false)
+                                }
+                                self.loadedImage = value.image
+                                self.animating = false
+                            }
+
+                            CallbackQueue.mainAsync.execute {
+                                context.onSuccessDelegate.call(value)
+                            }
+                        case .failure(let error):
+                            CallbackQueue.mainCurrentOrAsync.execute {
+                                if let image = context.options.onFailureImage {
+                                    self.loadedImage = image
+                                }
+                                self.markLoaded(sendChangeEvent: true)
+                            }
+                            
+                            CallbackQueue.mainAsync.execute {
+                                context.onFailureDelegate.call(error)
+                            }
+                        }
+                })
+        }
+        
+        private func updateProgress(downloaded: Int64, total: Int64) {
+            progress.totalUnitCount = total
+            progress.completedUnitCount = downloaded
+            objectWillChange.send()
+        }
+
+        /// Cancels the download task if it is in progress.
+        func cancel() {
+            downloadTask?.cancel()
+            downloadTask = nil
+            loading = false
+        }
+    }
+}
+#endif

Pods/Kingfisher/Sources/SwiftUI/ImageContext.swift

@@ -0,0 +1,102 @@
+//
+//  ImageContext.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2021/05/08.
+//
+//  Copyright (c) 2021 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if canImport(SwiftUI) && canImport(Combine)
+import SwiftUI
+import Combine
+
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+extension KFImage {
+    public class Context<HoldingView: KFImageHoldingView> {
+        let source: Source?
+        var options = KingfisherParsedOptionsInfo(
+            KingfisherManager.shared.defaultOptions + [.loadDiskFileSynchronously]
+        )
+
+        var configurations: [(HoldingView) -> HoldingView] = []
+        var renderConfigurations: [(HoldingView.RenderingView) -> Void] = []
+        var contentConfiguration: ((HoldingView) -> AnyView)? = nil
+        
+        var cancelOnDisappear: Bool = false
+        var placeholder: ((Progress) -> AnyView)? = nil
+
+        let onFailureDelegate = Delegate<KingfisherError, Void>()
+        let onSuccessDelegate = Delegate<RetrieveImageResult, Void>()
+        let onProgressDelegate = Delegate<(Int64, Int64), Void>()
+        
+        var startLoadingBeforeViewAppear: Bool = false
+        
+        init(source: Source?) {
+            self.source = source
+        }
+        
+        func shouldApplyFade(cacheType: CacheType) -> Bool {
+            options.forceTransition || cacheType == .none
+        }
+
+        func fadeTransitionDuration(cacheType: CacheType) -> TimeInterval? {
+            shouldApplyFade(cacheType: cacheType)
+            ? options.transition.fadeDuration
+                : nil
+        }
+    }
+}
+
+extension ImageTransition {
+    // Only for fade effect in SwiftUI.
+    fileprivate var fadeDuration: TimeInterval? {
+        switch self {
+        case .fade(let duration):
+            return duration
+        default:
+            return nil
+        }
+    }
+}
+
+
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+extension KFImage.Context: Hashable {
+    public static func == (lhs: KFImage.Context<HoldingView>, rhs: KFImage.Context<HoldingView>) -> Bool {
+        lhs.source == rhs.source &&
+        lhs.options.processor.identifier == rhs.options.processor.identifier
+    }
+
+    public func hash(into hasher: inout Hasher) {
+        hasher.combine(source)
+        hasher.combine(options.processor.identifier)
+    }
+}
+
+#if canImport(UIKit) && !os(watchOS)
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+extension KFAnimatedImage {
+    public typealias Context = KFImage.Context
+    typealias ImageBinder = KFImage.ImageBinder
+}
+#endif
+
+#endif

Pods/Kingfisher/Sources/SwiftUI/KFAnimatedImage.swift

@@ -0,0 +1,96 @@
+//
+//  KFAnimatedImage.swift
+//  Kingfisher
+//
+//  Created by wangxingbin on 2021/4/29.
+//
+//  Copyright (c) 2021 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if canImport(SwiftUI) && canImport(Combine) && canImport(UIKit) && !os(watchOS)
+import SwiftUI
+import Combine
+
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+public struct KFAnimatedImage: KFImageProtocol {
+    public typealias HoldingView = KFAnimatedImageViewRepresenter
+    public var context: Context<HoldingView>
+    public init(context: KFImage.Context<HoldingView>) {
+        self.context = context
+    }
+    
+    /// Configures current rendering view with a `block`. This block will be applied when the under-hood
+    /// `AnimatedImageView` is created in `UIViewRepresentable.makeUIView(context:)`
+    ///
+    /// - Parameter block: The block applies to the animated image view.
+    /// - Returns: A `KFAnimatedImage` view that being configured by the `block`.
+    public func configure(_ block: @escaping (HoldingView.RenderingView) -> Void) -> Self {
+        context.renderConfigurations.append(block)
+        return self
+    }
+}
+
+/// A wrapped `UIViewRepresentable` of `AnimatedImageView`
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+public struct KFAnimatedImageViewRepresenter: UIViewRepresentable, KFImageHoldingView {
+    public typealias RenderingView = AnimatedImageView
+    public static func created(from image: KFCrossPlatformImage?, context: KFImage.Context<Self>) -> KFAnimatedImageViewRepresenter {
+        KFAnimatedImageViewRepresenter(image: image, context: context)
+    }
+    
+    var image: KFCrossPlatformImage?
+    let context: KFImage.Context<KFAnimatedImageViewRepresenter>
+    
+    public func makeUIView(context: Context) -> AnimatedImageView {
+        let view = AnimatedImageView()
+        
+        self.context.renderConfigurations.forEach { $0(view) }
+        
+        view.image = image
+        
+        // Allow SwiftUI scale (fit/fill) working fine.
+        view.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
+        view.setContentCompressionResistancePriority(.defaultLow, for: .vertical)
+        return view
+    }
+    
+    public func updateUIView(_ uiView: AnimatedImageView, context: Context) {
+        uiView.image = image
+    }
+}
+
+#if DEBUG
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+struct KFAnimatedImage_Previews: PreviewProvider {
+    static var previews: some View {
+        Group {
+            KFAnimatedImage(source: .network(URL(string: "https://raw.githubusercontent.com/onevcat/Kingfisher-TestImages/master/DemoAppImage/GIF/1.gif")!))
+                .onSuccess { r in
+                    print(r)
+                }
+                .placeholder {
+                    ProgressView()
+                }
+                .padding()
+        }
+    }
+}
+#endif
+#endif

Pods/Kingfisher/Sources/SwiftUI/KFImage.swift

@@ -0,0 +1,106 @@
+//
+//  KFImage.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2019/06/26.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if canImport(SwiftUI) && canImport(Combine)
+import SwiftUI
+import Combine
+
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+public struct KFImage: KFImageProtocol {
+    public var context: Context<Image>
+    public init(context: Context<Image>) {
+        self.context = context
+    }
+}
+
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+extension Image: KFImageHoldingView {
+    public typealias RenderingView = Image
+    public static func created(from image: KFCrossPlatformImage?, context: KFImage.Context<Self>) -> Image {
+        Image(crossPlatformImage: image)
+    }
+}
+
+// MARK: - Image compatibility.
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+extension KFImage {
+
+    public func resizable(
+        capInsets: EdgeInsets = EdgeInsets(),
+        resizingMode: Image.ResizingMode = .stretch) -> KFImage
+    {
+        configure { $0.resizable(capInsets: capInsets, resizingMode: resizingMode) }
+    }
+
+    public func renderingMode(_ renderingMode: Image.TemplateRenderingMode?) -> KFImage {
+        configure { $0.renderingMode(renderingMode) }
+    }
+
+    public func interpolation(_ interpolation: Image.Interpolation) -> KFImage {
+        configure { $0.interpolation(interpolation) }
+    }
+
+    public func antialiased(_ isAntialiased: Bool) -> KFImage {
+        configure { $0.antialiased(isAntialiased) }
+    }
+    
+    /// Starts the loading process of `self` immediately.
+    ///
+    /// By default, a `KFImage` will not load its source until the `onAppear` is called. This is a lazily loading
+    /// behavior and provides better performance. However, when you refresh the view, the lazy loading also causes a
+    /// flickering since the loading does not happen immediately. Call this method if you want to start the load at once
+    /// could help avoiding the flickering, with some performance trade-off.
+    ///
+    /// - Deprecated: This is not necessary anymore since `@StateObject` is used for holding the image data.
+    /// It does nothing now and please just remove it.
+    ///
+    /// - Returns: The `Self` value with changes applied.
+    @available(*, deprecated, message: "This is not necessary anymore since `@StateObject` is used. It does nothing now and please just remove it.")
+    public func loadImmediately(_ start: Bool = true) -> KFImage {
+        return self
+    }
+}
+
+#if DEBUG
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+struct KFImage_Previews: PreviewProvider {
+    static var previews: some View {
+        Group {
+            KFImage.url(URL(string: "https://raw.githubusercontent.com/onevcat/Kingfisher/master/images/logo.png")!)
+                .onSuccess { r in
+                    print(r)
+                }
+                .placeholder { p in
+                    ProgressView(p)
+                }
+                .resizable()
+                .aspectRatio(contentMode: .fit)
+                .padding()
+        }
+    }
+}
+#endif
+#endif

Pods/Kingfisher/Sources/SwiftUI/KFImageOptions.swift

@@ -0,0 +1,158 @@
+//
+//  KFImageOptions.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2020/12/20.
+//
+//  Copyright (c) 2020 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if canImport(SwiftUI) && canImport(Combine)
+import SwiftUI
+import Combine
+
+// MARK: - KFImage creating.
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+extension KFImageProtocol {
+
+    /// Creates a `KFImage` for a given `Source`.
+    /// - Parameters:
+    ///   - source: The `Source` object defines data information from network or a data provider.
+    /// - Returns: A `KFImage` for future configuration or embedding to a `SwiftUI.View`.
+    public static func source(
+        _ source: Source?
+    ) -> Self
+    {
+        Self.init(source: source)
+    }
+
+    /// Creates a `KFImage` for a given `Resource`.
+    /// - Parameters:
+    ///   - source: The `Resource` object defines data information like key or URL.
+    /// - Returns: A `KFImage` for future configuration or embedding to a `SwiftUI.View`.
+    public static func resource(
+        _ resource: Resource?
+    ) -> Self
+    {
+        source(resource?.convertToSource())
+    }
+
+    /// Creates a `KFImage` for a given `URL`.
+    /// - Parameters:
+    ///   - url: The URL where the image should be downloaded.
+    ///   - cacheKey: The key used to store the downloaded image in cache.
+    ///               If `nil`, the `absoluteString` of `url` is used as the cache key.
+    /// - Returns: A `KFImage` for future configuration or embedding to a `SwiftUI.View`.
+    public static func url(
+        _ url: URL?, cacheKey: String? = nil
+    ) -> Self
+    {
+        source(url?.convertToSource(overrideCacheKey: cacheKey))
+    }
+
+    /// Creates a `KFImage` for a given `ImageDataProvider`.
+    /// - Parameters:
+    ///   - provider: The `ImageDataProvider` object contains information about the data.
+    /// - Returns: A `KFImage` for future configuration or embedding to a `SwiftUI.View`.
+    public static func dataProvider(
+        _ provider: ImageDataProvider?
+    ) -> Self
+    {
+        source(provider?.convertToSource())
+    }
+
+    /// Creates a builder for some given raw data and a cache key.
+    /// - Parameters:
+    ///   - data: The data object from which the image should be created.
+    ///   - cacheKey: The key used to store the downloaded image in cache.
+    /// - Returns: A `KFImage` for future configuration or embedding to a `SwiftUI.View`.
+    public static func data(
+        _ data: Data?, cacheKey: String
+    ) -> Self
+    {
+        if let data = data {
+            return dataProvider(RawImageDataProvider(data: data, cacheKey: cacheKey))
+        } else {
+            return dataProvider(nil)
+        }
+    }
+}
+
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+extension KFImageProtocol {
+    /// Sets a placeholder `View` which shows when loading the image, with a progress parameter as input.
+    /// - Parameter content: A view that describes the placeholder.
+    /// - Returns: A `KFImage` view that contains `content` as its placeholder.
+    public func placeholder<P: View>(@ViewBuilder _ content: @escaping (Progress) -> P) -> Self {
+        context.placeholder = { progress in
+            return AnyView(content(progress))
+        }
+        return self
+    }
+    
+    /// Sets a placeholder `View` which shows when loading the image.
+    /// - Parameter content: A view that describes the placeholder.
+    /// - Returns: A `KFImage` view that contains `content` as its placeholder.
+    public func placeholder<P: View>(@ViewBuilder _ content: @escaping () -> P) -> Self {
+        placeholder { _ in content() }
+    }
+
+    /// Sets cancelling the download task bound to `self` when the view disappearing.
+    /// - Parameter flag: Whether cancel the task or not.
+    /// - Returns: A `KFImage` view that cancels downloading task when disappears.
+    public func cancelOnDisappear(_ flag: Bool) -> Self {
+        context.cancelOnDisappear = flag
+        return self
+    }
+
+    /// Sets a fade transition for the image task.
+    /// - Parameter duration: The duration of the fade transition.
+    /// - Returns: A `KFImage` with changes applied.
+    ///
+    /// Kingfisher will use the fade transition to animate the image in if it is downloaded from web.
+    /// The transition will not happen when the
+    /// image is retrieved from either memory or disk cache by default. If you need to do the transition even when
+    /// the image being retrieved from cache, also call `forceRefresh()` on the returned `KFImage`.
+    public func fade(duration: TimeInterval) -> Self {
+        context.options.transition = .fade(duration)
+        return self
+    }
+    
+    /// Sets whether to start the image loading before the view actually appears.
+    ///
+    /// By default, Kingfisher performs a lazy loading for `KFImage`. The image loading won't start until the view's
+    /// `onAppear` is called. However, sometimes you may want to trigger an aggressive loading for the view. By enabling
+    /// this, the `KFImage` will try to load the view when its `body` is evaluated when the image loading is not yet
+    /// started or a previous loading did fail.
+    ///
+    /// - Parameter flag: Whether the image loading should happen before view appear. Default is `true`.
+    /// - Returns: A `KFImage` with changes applied.
+    ///
+    /// - Note: This is a temporary workaround for an issue from iOS 16, where the SwiftUI view's `onAppear` is not
+    /// called when it is deeply embedded inside a `List` or `ForEach`.
+    /// See [#1988](https://github.com/onevcat/Kingfisher/issues/1988). It may cause performance regression, especially
+    /// if you have a lot of images to load in the view. Use it as your own risk.
+    ///
+    public func startLoadingBeforeViewAppear(_ flag: Bool = true) -> Self {
+        context.startLoadingBeforeViewAppear = flag
+        return self
+    }
+}
+#endif

Pods/Kingfisher/Sources/SwiftUI/KFImageProtocol.swift

@@ -0,0 +1,112 @@
+//
+//  KFImageProtocol.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2021/05/08.
+//
+//  Copyright (c) 2021 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if canImport(SwiftUI) && canImport(Combine)
+import SwiftUI
+import Combine
+
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+public protocol KFImageProtocol: View, KFOptionSetter {
+    associatedtype HoldingView: KFImageHoldingView
+    var context: KFImage.Context<HoldingView> { get set }
+    init(context: KFImage.Context<HoldingView>)
+}
+
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+extension KFImageProtocol {
+    public var body: some View {
+        ZStack {
+            KFImageRenderer<HoldingView>(
+                context: context
+            ).id(context)
+        }
+    }
+    
+    /// Creates a Kingfisher compatible image view to load image from the given `Source`.
+    /// - Parameters:
+    ///   - source: The image `Source` defining where to load the target image.
+    public init(source: Source?) {
+        let context = KFImage.Context<HoldingView>(source: source)
+        self.init(context: context)
+    }
+
+    /// Creates a Kingfisher compatible image view to load image from the given `URL`.
+    /// - Parameters:
+    ///   - source: The image `Source` defining where to load the target image.
+    public init(_ url: URL?) {
+        self.init(source: url?.convertToSource())
+    }
+    
+    /// Configures current image with a `block` and return another `Image` to use as the final content.
+    ///
+    /// This block will be lazily applied when creating the final `Image`.
+    ///
+    /// If multiple `configure` modifiers are added to the image, they will be evaluated by order. If you want to
+    /// configure the input image (which is usually an `Image` value) to a non-`Image` value, use `contentConfigure`.
+    ///
+    /// - Parameter block: The block applies to loaded image. The block should return an `Image` that is configured.
+    /// - Returns: A `KFImage` view that configures internal `Image` with `block`.
+    public func configure(_ block: @escaping (HoldingView) -> HoldingView) -> Self {
+        context.configurations.append(block)
+        return self
+    }
+
+    /// Configures current image with a `block` and return a `View` to use as the final content.
+    ///
+    /// This block will be lazily applied when creating the final `Image`.
+    ///
+    /// If multiple `contentConfigure` modifiers are added to the image, only the last one will be stored and used.
+    ///
+    /// - Parameter block: The block applies to the loaded image. The block should return a `View` that is configured.
+    /// - Returns: A `KFImage` view that configures internal `Image` with `block`.
+    public func contentConfigure<V: View>(_ block: @escaping (HoldingView) -> V) -> Self {
+        context.contentConfiguration = { AnyView(block($0)) }
+        return self
+    }
+}
+
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+public protocol KFImageHoldingView: View {
+    associatedtype RenderingView
+    static func created(from image: KFCrossPlatformImage?, context: KFImage.Context<Self>) -> Self
+}
+
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+extension KFImageProtocol {
+    public var options: KingfisherParsedOptionsInfo {
+        get { context.options }
+        nonmutating set { context.options = newValue }
+    }
+
+    public var onFailureDelegate: Delegate<KingfisherError, Void> { context.onFailureDelegate }
+    public var onSuccessDelegate: Delegate<RetrieveImageResult, Void> { context.onSuccessDelegate }
+    public var onProgressDelegate: Delegate<(Int64, Int64), Void> { context.onProgressDelegate }
+
+    public var delegateObserver: AnyObject { context }
+}
+
+
+#endif

Pods/Kingfisher/Sources/SwiftUI/KFImageRenderer.swift

@@ -0,0 +1,129 @@
+//
+//  KFImageRenderer.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2021/05/08.
+//
+//  Copyright (c) 2021 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if canImport(SwiftUI) && canImport(Combine)
+import SwiftUI
+import Combine
+
+/// A Kingfisher compatible SwiftUI `View` to load an image from a `Source`.
+/// Declaring a `KFImage` in a `View`'s body to trigger loading from the given `Source`.
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+struct KFImageRenderer<HoldingView> : View where HoldingView: KFImageHoldingView {
+    
+    @StateObject var binder: KFImage.ImageBinder = .init()
+    let context: KFImage.Context<HoldingView>
+    
+    var body: some View {
+        if context.startLoadingBeforeViewAppear && !binder.loadingOrSucceeded && !binder.animating {
+            binder.markLoading()
+            DispatchQueue.main.async { binder.start(context: context) }
+        }
+        
+        return ZStack {
+            renderedImage().opacity(binder.loaded ? 1.0 : 0.0)
+            if binder.loadedImage == nil {
+                ZStack {
+                    if let placeholder = context.placeholder {
+                        placeholder(binder.progress)
+                    } else {
+                        Color.clear
+                    }
+                }
+                .onAppear { [weak binder = self.binder] in
+                    guard let binder = binder else {
+                        return
+                    }
+                    if !binder.loadingOrSucceeded {
+                        binder.start(context: context)
+                    }
+                }
+                .onDisappear { [weak binder = self.binder] in
+                    guard let binder = binder else {
+                        return
+                    }
+                    if context.cancelOnDisappear {
+                        binder.cancel()
+                    }
+                }
+            }
+        }
+        // Workaround for https://github.com/onevcat/Kingfisher/issues/1988
+        // on iOS 16 there seems to be a bug that when in a List, the `onAppear` of the `ZStack` above in the
+        // `binder.loadedImage == nil` not get called. Adding this empty `onAppear` fixes it and the life cycle can
+        // work again.
+        //
+        // There is another "fix": adding an `else` clause and put a `Color.clear` there. But I believe this `onAppear`
+        // should work better.
+        //
+        // It should be a bug in iOS 16, I guess it is some kinds of over-optimization in list cell loading caused it.
+        .onAppear()
+    }
+    
+    @ViewBuilder
+    private func renderedImage() -> some View {
+        let configuredImage = context.configurations
+            .reduce(HoldingView.created(from: binder.loadedImage, context: context)) {
+                current, config in config(current)
+            }
+        if let contentConfiguration = context.contentConfiguration {
+            contentConfiguration(configuredImage)
+        } else {
+            configuredImage
+        }
+    }
+}
+
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+extension Image {
+    // Creates an Image with either UIImage or NSImage.
+    init(crossPlatformImage: KFCrossPlatformImage?) {
+        #if canImport(UIKit)
+        self.init(uiImage: crossPlatformImage ?? KFCrossPlatformImage())
+        #elseif canImport(AppKit)
+        self.init(nsImage: crossPlatformImage ?? KFCrossPlatformImage())
+        #endif
+    }
+}
+
+#if canImport(UIKit)
+@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
+extension UIImage.Orientation {
+    func toSwiftUI() -> Image.Orientation {
+        switch self {
+        case .down: return .down
+        case .up: return .up
+        case .left: return .left
+        case .right: return .right
+        case .upMirrored: return .upMirrored
+        case .downMirrored: return .downMirrored
+        case .leftMirrored: return .leftMirrored
+        case .rightMirrored: return .rightMirrored
+        @unknown default: return .up
+        }
+    }
+}
+#endif
+#endif

Pods/Kingfisher/Sources/Utility/Box.swift

@@ -0,0 +1,34 @@
+//
+//  Box.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2018/3/17.
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+class Box<T> {
+    var value: T
+    
+    init(_ value: T) {
+        self.value = value
+    }
+}

Pods/Kingfisher/Sources/Utility/CallbackQueue.swift

@@ -0,0 +1,83 @@
+//
+//  CallbackQueue.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2018/10/15.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+public typealias ExecutionQueue = CallbackQueue
+
+/// Represents callback queue behaviors when an calling of closure be dispatched.
+///
+/// - asyncMain: Dispatch the calling to `DispatchQueue.main` with an `async` behavior.
+/// - currentMainOrAsync: Dispatch the calling to `DispatchQueue.main` with an `async` behavior if current queue is not
+///                       `.main`. Otherwise, call the closure immediately in current main queue.
+/// - untouch: Do not change the calling queue for closure.
+/// - dispatch: Dispatches to a specified `DispatchQueue`.
+public enum CallbackQueue {
+    /// Dispatch the calling to `DispatchQueue.main` with an `async` behavior.
+    case mainAsync
+    /// Dispatch the calling to `DispatchQueue.main` with an `async` behavior if current queue is not
+    /// `.main`. Otherwise, call the closure immediately in current main queue.
+    case mainCurrentOrAsync
+    /// Do not change the calling queue for closure.
+    case untouch
+    /// Dispatches to a specified `DispatchQueue`.
+    case dispatch(DispatchQueue)
+    
+    public func execute(_ block: @escaping () -> Void) {
+        switch self {
+        case .mainAsync:
+            DispatchQueue.main.async { block() }
+        case .mainCurrentOrAsync:
+            DispatchQueue.main.safeAsync { block() }
+        case .untouch:
+            block()
+        case .dispatch(let queue):
+            queue.async { block() }
+        }
+    }
+
+    var queue: DispatchQueue {
+        switch self {
+        case .mainAsync: return .main
+        case .mainCurrentOrAsync: return .main
+        case .untouch: return OperationQueue.current?.underlyingQueue ?? .main
+        case .dispatch(let queue): return queue
+        }
+    }
+}
+
+extension DispatchQueue {
+    // This method will dispatch the `block` to self.
+    // If `self` is the main queue, and current thread is main thread, the block
+    // will be invoked immediately instead of being dispatched.
+    func safeAsync(_ block: @escaping () -> Void) {
+        if self === DispatchQueue.main && Thread.isMainThread {
+            block()
+        } else {
+            async { block() }
+        }
+    }
+}

Pods/Kingfisher/Sources/Utility/Delegate.swift

@@ -0,0 +1,132 @@
+//
+//  Delegate.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2018/10/10.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+/// A class that keeps a weakly reference for `self` when implementing `onXXX` behaviors.
+/// Instead of remembering to keep `self` as weak in a stored closure:
+///
+/// ```swift
+/// // MyClass.swift
+/// var onDone: (() -> Void)?
+/// func done() {
+///     onDone?()
+/// }
+///
+/// // ViewController.swift
+/// var obj: MyClass?
+///
+/// func doSomething() {
+///     obj = MyClass()
+///     obj!.onDone = { [weak self] in
+///         self?.reportDone()
+///     }
+/// }
+/// ```
+///
+/// You can create a `Delegate` and observe on `self`. Now, there is no retain cycle inside:
+///
+/// ```swift
+/// // MyClass.swift
+/// let onDone = Delegate<(), Void>()
+/// func done() {
+///     onDone.call()
+/// }
+///
+/// // ViewController.swift
+/// var obj: MyClass?
+///
+/// func doSomething() {
+///     obj = MyClass()
+///     obj!.onDone.delegate(on: self) { (self, _)
+///         // `self` here is shadowed and does not keep a strong ref.
+///         // So you can release both `MyClass` instance and `ViewController` instance.
+///         self.reportDone()
+///     }
+/// }
+/// ```
+///
+public class Delegate<Input, Output> {
+    public init() {}
+
+    private var block: ((Input) -> Output?)?
+    public func delegate<T: AnyObject>(on target: T, block: ((T, Input) -> Output)?) {
+        self.block = { [weak target] input in
+            guard let target = target else { return nil }
+            return block?(target, input)
+        }
+    }
+
+    public func call(_ input: Input) -> Output? {
+        return block?(input)
+    }
+
+    public func callAsFunction(_ input: Input) -> Output? {
+        return call(input)
+    }
+}
+
+extension Delegate where Input == Void {
+    public func call() -> Output? {
+        return call(())
+    }
+
+    public func callAsFunction() -> Output? {
+        return call()
+    }
+}
+
+extension Delegate where Input == Void, Output: OptionalProtocol {
+    public func call() -> Output {
+        return call(())
+    }
+
+    public func callAsFunction() -> Output {
+        return call()
+    }
+}
+
+extension Delegate where Output: OptionalProtocol {
+    public func call(_ input: Input) -> Output {
+        if let result = block?(input) {
+            return result
+        } else {
+            return Output._createNil
+        }
+    }
+
+    public func callAsFunction(_ input: Input) -> Output {
+        return call(input)
+    }
+}
+
+public protocol OptionalProtocol {
+    static var _createNil: Self { get }
+}
+extension Optional : OptionalProtocol {
+    public static var _createNil: Optional<Wrapped> {
+         return nil
+    }
+}

Pods/Kingfisher/Sources/Utility/ExtensionHelpers.swift

@@ -0,0 +1,117 @@
+//
+//  ExtensionHelpers.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2018/09/28.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+extension CGFloat {
+    var isEven: Bool {
+        return truncatingRemainder(dividingBy: 2.0) == 0
+    }
+}
+
+#if canImport(AppKit) && !targetEnvironment(macCatalyst)
+import AppKit
+extension NSBezierPath {
+    convenience init(roundedRect rect: NSRect, topLeftRadius: CGFloat, topRightRadius: CGFloat,
+                     bottomLeftRadius: CGFloat, bottomRightRadius: CGFloat)
+    {
+        self.init()
+        
+        let maxCorner = min(rect.width, rect.height) / 2
+        
+        let radiusTopLeft = min(maxCorner, max(0, topLeftRadius))
+        let radiusTopRight = min(maxCorner, max(0, topRightRadius))
+        let radiusBottomLeft = min(maxCorner, max(0, bottomLeftRadius))
+        let radiusBottomRight = min(maxCorner, max(0, bottomRightRadius))
+        
+        guard !rect.isEmpty else {
+            return
+        }
+        
+        let topLeft = NSPoint(x: rect.minX, y: rect.maxY)
+        let topRight = NSPoint(x: rect.maxX, y: rect.maxY)
+        let bottomRight = NSPoint(x: rect.maxX, y: rect.minY)
+        
+        move(to: NSPoint(x: rect.midX, y: rect.maxY))
+        appendArc(from: topLeft, to: rect.origin, radius: radiusTopLeft)
+        appendArc(from: rect.origin, to: bottomRight, radius: radiusBottomLeft)
+        appendArc(from: bottomRight, to: topRight, radius: radiusBottomRight)
+        appendArc(from: topRight, to: topLeft, radius: radiusTopRight)
+        close()
+    }
+    
+    convenience init(roundedRect rect: NSRect, byRoundingCorners corners: RectCorner, radius: CGFloat) {
+        let radiusTopLeft = corners.contains(.topLeft) ? radius : 0
+        let radiusTopRight = corners.contains(.topRight) ? radius : 0
+        let radiusBottomLeft = corners.contains(.bottomLeft) ? radius : 0
+        let radiusBottomRight = corners.contains(.bottomRight) ? radius : 0
+        
+        self.init(roundedRect: rect, topLeftRadius: radiusTopLeft, topRightRadius: radiusTopRight,
+                  bottomLeftRadius: radiusBottomLeft, bottomRightRadius: radiusBottomRight)
+    }
+}
+
+extension KFCrossPlatformImage {
+    // macOS does not support scale. This is just for code compatibility across platforms.
+    convenience init?(data: Data, scale: CGFloat) {
+        self.init(data: data)
+    }
+}
+#endif
+
+#if canImport(UIKit)
+import UIKit
+extension RectCorner {
+    var uiRectCorner: UIRectCorner {
+        
+        var result: UIRectCorner = []
+        
+        if contains(.topLeft) { result.insert(.topLeft) }
+        if contains(.topRight) { result.insert(.topRight) }
+        if contains(.bottomLeft) { result.insert(.bottomLeft) }
+        if contains(.bottomRight) { result.insert(.bottomRight) }
+        
+        return result
+    }
+}
+#endif
+
+extension Date {
+    var isPast: Bool {
+        return isPast(referenceDate: Date())
+    }
+
+    func isPast(referenceDate: Date) -> Bool {
+        return timeIntervalSince(referenceDate) <= 0
+    }
+
+    // `Date` in memory is a wrap for `TimeInterval`. But in file attribute it can only accept `Int` number.
+    // By default the system will `round` it. But it is not friendly for testing purpose.
+    // So we always `ceil` the value when used for file attributes.
+    var fileAttributeDate: Date {
+        return Date(timeIntervalSince1970: ceil(timeIntervalSince1970))
+    }
+}

Pods/Kingfisher/Sources/Utility/Result.swift

@@ -0,0 +1,50 @@
+//
+//  Result.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2018/09/22.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+// These helper methods are not public since we do not want them to be exposed or cause any conflicting.
+// However, they are just wrapper of `ResultUtil` static methods.
+extension Result where Failure: Error {
+
+    /// Evaluates the given transform closures to create a single output value.
+    ///
+    /// - Parameters:
+    ///   - onSuccess: A closure that transforms the success value.
+    ///   - onFailure: A closure that transforms the error value.
+    /// - Returns: A single `Output` value.
+    func match<Output>(
+        onSuccess: (Success) -> Output,
+        onFailure: (Failure) -> Output) -> Output
+    {
+        switch self {
+        case let .success(value):
+            return onSuccess(value)
+        case let .failure(error):
+            return onFailure(error)
+        }
+    }
+}

Pods/Kingfisher/Sources/Utility/Runtime.swift

@@ -0,0 +1,35 @@
+//
+//  Runtime.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 2018/10/12.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+
+func getAssociatedObject<T>(_ object: Any, _ key: UnsafeRawPointer) -> T? {
+    return objc_getAssociatedObject(object, key) as? T
+}
+
+func setRetainedAssociatedObject<T>(_ object: Any, _ key: UnsafeRawPointer, _ value: T) {
+    objc_setAssociatedObject(object, key, value, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
+}

Pods/Kingfisher/Sources/Utility/SizeExtensions.swift

@@ -0,0 +1,110 @@
+//
+//  SizeExtensions.swift
+//  Kingfisher
+//
+//  Created by onevcat on 2018/09/28.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import CoreGraphics
+
+extension CGSize: KingfisherCompatibleValue {}
+extension KingfisherWrapper where Base == CGSize {
+    
+    /// Returns a size by resizing the `base` size to a target size under a given content mode.
+    ///
+    /// - Parameters:
+    ///   - size: The target size to resize to.
+    ///   - contentMode: Content mode of the target size should be when resizing.
+    /// - Returns: The resized size under the given `ContentMode`.
+    public func resize(to size: CGSize, for contentMode: ContentMode) -> CGSize {
+        switch contentMode {
+        case .aspectFit:
+            return constrained(size)
+        case .aspectFill:
+            return filling(size)
+        case .none:
+            return size
+        }
+    }
+    
+    /// Returns a size by resizing the `base` size by making it aspect fitting the given `size`.
+    ///
+    /// - Parameter size: The size in which the `base` should fit in.
+    /// - Returns: The size fitted in by the input `size`, while keeps `base` aspect.
+    public func constrained(_ size: CGSize) -> CGSize {
+        let aspectWidth = round(aspectRatio * size.height)
+        let aspectHeight = round(size.width / aspectRatio)
+        
+        return aspectWidth > size.width ?
+            CGSize(width: size.width, height: aspectHeight) :
+            CGSize(width: aspectWidth, height: size.height)
+    }
+    
+    /// Returns a size by resizing the `base` size by making it aspect filling the given `size`.
+    ///
+    /// - Parameter size: The size in which the `base` should fill.
+    /// - Returns: The size be filled by the input `size`, while keeps `base` aspect.
+    public func filling(_ size: CGSize) -> CGSize {
+        let aspectWidth = round(aspectRatio * size.height)
+        let aspectHeight = round(size.width / aspectRatio)
+        
+        return aspectWidth < size.width ?
+            CGSize(width: size.width, height: aspectHeight) :
+            CGSize(width: aspectWidth, height: size.height)
+    }
+    
+    /// Returns a `CGRect` for which the `base` size is constrained to an input `size` at a given `anchor` point.
+    ///
+    /// - Parameters:
+    ///   - size: The size in which the `base` should be constrained to.
+    ///   - anchor: An anchor point in which the size constraint should happen.
+    /// - Returns: The result `CGRect` for the constraint operation.
+    public func constrainedRect(for size: CGSize, anchor: CGPoint) -> CGRect {
+        
+        let unifiedAnchor = CGPoint(x: anchor.x.clamped(to: 0.0...1.0),
+                                    y: anchor.y.clamped(to: 0.0...1.0))
+        
+        let x = unifiedAnchor.x * base.width - unifiedAnchor.x * size.width
+        let y = unifiedAnchor.y * base.height - unifiedAnchor.y * size.height
+        let r = CGRect(x: x, y: y, width: size.width, height: size.height)
+        
+        let ori = CGRect(origin: .zero, size: base)
+        return ori.intersection(r)
+    }
+    
+    private var aspectRatio: CGFloat {
+        return base.height == 0.0 ? 1.0 : base.width / base.height
+    }
+}
+
+extension CGRect {
+    func scaled(_ scale: CGFloat) -> CGRect {
+        return CGRect(x: origin.x * scale, y: origin.y * scale,
+                      width: size.width * scale, height: size.height * scale)
+    }
+}
+
+extension Comparable {
+    func clamped(to limits: ClosedRange<Self>) -> Self {
+        return min(max(self, limits.lowerBound), limits.upperBound)
+    }
+}

Pods/Kingfisher/Sources/Utility/String+MD5.swift

@@ -0,0 +1,278 @@
+//
+//  String+MD5.swift
+//  Kingfisher
+//
+//  Created by Wei Wang on 18/09/25.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+import Foundation
+import CommonCrypto
+
+extension String: KingfisherCompatibleValue { }
+extension KingfisherWrapper where Base == String {
+    var md5: String {
+        guard let data = base.data(using: .utf8) else {
+            return base
+        }
+
+        let message = data.withUnsafeBytes { (bytes: UnsafeRawBufferPointer) in
+            return [UInt8](bytes)
+        }
+
+        let MD5Calculator = MD5(message)
+        let MD5Data = MD5Calculator.calculate()
+
+        var MD5String = String()
+        for c in MD5Data {
+            MD5String += String(format: "%02x", c)
+        }
+        return MD5String
+    }
+
+    var ext: String? {
+        var ext = ""
+        if let index = base.lastIndex(of: ".") {
+            let extRange = base.index(index, offsetBy: 1)..<base.endIndex
+            ext = String(base[extRange])
+        }
+        guard let firstSeg = ext.split(separator: "@").first else {
+            return nil
+        }
+        return firstSeg.count > 0 ? String(firstSeg) : nil
+    }
+}
+
+// array of bytes, little-endian representation
+func arrayOfBytes<T>(_ value: T, length: Int? = nil) -> [UInt8] {
+    let totalBytes = length ?? (MemoryLayout<T>.size * 8)
+
+    let valuePointer = UnsafeMutablePointer<T>.allocate(capacity: 1)
+    valuePointer.pointee = value
+
+    let bytes = valuePointer.withMemoryRebound(to: UInt8.self, capacity: totalBytes) { (bytesPointer) -> [UInt8] in
+        var bytes = [UInt8](repeating: 0, count: totalBytes)
+        for j in 0..<min(MemoryLayout<T>.size, totalBytes) {
+            bytes[totalBytes - 1 - j] = (bytesPointer + j).pointee
+        }
+        return bytes
+    }
+    
+    valuePointer.deinitialize(count: 1)
+    valuePointer.deallocate()
+
+    return bytes
+}
+
+extension Int {
+    // Array of bytes with optional padding (little-endian)
+    func bytes(_ totalBytes: Int = MemoryLayout<Int>.size) -> [UInt8] {
+        return arrayOfBytes(self, length: totalBytes)
+    }
+
+}
+
+protocol HashProtocol {
+    var message: [UInt8] { get }
+    // Common part for hash calculation. Prepare header data.
+    func prepare(_ len: Int) -> [UInt8]
+}
+
+extension HashProtocol {
+
+    func prepare(_ len: Int) -> [UInt8] {
+        var tmpMessage = message
+
+        // Step 1. Append Padding Bits
+        tmpMessage.append(0x80) // append one bit (UInt8 with one bit) to message
+
+        // append "0" bit until message length in bits ≡ 448 (mod 512)
+        var msgLength = tmpMessage.count
+        var counter = 0
+
+        while msgLength % len != (len - 8) {
+            counter += 1
+            msgLength += 1
+        }
+
+        tmpMessage += [UInt8](repeating: 0, count: counter)
+        return tmpMessage
+    }
+}
+
+func toUInt32Array(_ slice: ArraySlice<UInt8>) -> [UInt32] {
+    var result = [UInt32]()
+    result.reserveCapacity(16)
+
+    for idx in stride(from: slice.startIndex, to: slice.endIndex, by: MemoryLayout<UInt32>.size) {
+        let d0 = UInt32(slice[idx.advanced(by: 3)]) << 24
+        let d1 = UInt32(slice[idx.advanced(by: 2)]) << 16
+        let d2 = UInt32(slice[idx.advanced(by: 1)]) << 8
+        let d3 = UInt32(slice[idx])
+        let val: UInt32 = d0 | d1 | d2 | d3
+
+        result.append(val)
+    }
+    return result
+}
+
+struct BytesIterator: IteratorProtocol {
+
+    let chunkSize: Int
+    let data: [UInt8]
+
+    init(chunkSize: Int, data: [UInt8]) {
+        self.chunkSize = chunkSize
+        self.data = data
+    }
+
+    var offset = 0
+
+    mutating func next() -> ArraySlice<UInt8>? {
+        let end = min(chunkSize, data.count - offset)
+        let result = data[offset..<offset + end]
+        offset += result.count
+        return result.count > 0 ? result : nil
+    }
+}
+
+struct BytesSequence: Sequence {
+    let chunkSize: Int
+    let data: [UInt8]
+
+    func makeIterator() -> BytesIterator {
+        return BytesIterator(chunkSize: chunkSize, data: data)
+    }
+}
+
+func rotateLeft(_ value: UInt32, bits: UInt32) -> UInt32 {
+    return ((value << bits) & 0xFFFFFFFF) | (value >> (32 - bits))
+}
+
+class MD5: HashProtocol {
+
+    let message: [UInt8]
+
+    init (_ message: [UInt8]) {
+        self.message = message
+    }
+
+    // specifies the per-round shift amounts
+    private let shifts: [UInt32] = [7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22,
+                                    5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20,
+                                    4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23,
+                                    6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21]
+
+    // binary integer part of the sines of integers (Radians)
+    private let sines: [UInt32] = [0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,
+                                   0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
+                                   0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
+                                   0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
+                                   0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
+                                   0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
+                                   0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
+                                   0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
+                                   0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
+                                   0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
+                                   0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x4881d05,
+                                   0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
+                                   0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039,
+                                   0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
+                                   0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
+                                   0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391]
+
+    private let hashes: [UInt32] = [0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476]
+
+    func calculate() -> [UInt8] {
+        var tmpMessage = prepare(64)
+        tmpMessage.reserveCapacity(tmpMessage.count + 4)
+
+        // hash values
+        var hh = hashes
+
+        // Step 2. Append Length a 64-bit representation of lengthInBits
+        let lengthInBits = (message.count * 8)
+        let lengthBytes = lengthInBits.bytes(64 / 8)
+        tmpMessage += lengthBytes.reversed()
+
+        // Process the message in successive 512-bit chunks:
+        let chunkSizeBytes = 512 / 8 // 64
+
+        for chunk in BytesSequence(chunkSize: chunkSizeBytes, data: tmpMessage) {
+            // break chunk into sixteen 32-bit words M[j], 0 ≤ j ≤ 15
+            let M = toUInt32Array(chunk)
+            assert(M.count == 16, "Invalid array")
+
+            // Initialize hash value for this chunk:
+            var A: UInt32 = hh[0]
+            var B: UInt32 = hh[1]
+            var C: UInt32 = hh[2]
+            var D: UInt32 = hh[3]
+
+            var dTemp: UInt32 = 0
+
+            // Main loop
+            for j in 0 ..< sines.count {
+                var g = 0
+                var F: UInt32 = 0
+
+                switch j {
+                case 0...15:
+                    F = (B & C) | ((~B) & D)
+                    g = j
+                case 16...31:
+                    F = (D & B) | (~D & C)
+                    g = (5 * j + 1) % 16
+                case 32...47:
+                    F = B ^ C ^ D
+                    g = (3 * j + 5) % 16
+                case 48...63:
+                    F = C ^ (B | (~D))
+                    g = (7 * j) % 16
+                default:
+                    break
+                }
+                dTemp = D
+                D = C
+                C = B
+                B = B &+ rotateLeft((A &+ F &+ sines[j] &+ M[g]), bits: shifts[j])
+                A = dTemp
+            }
+
+            hh[0] = hh[0] &+ A
+            hh[1] = hh[1] &+ B
+            hh[2] = hh[2] &+ C
+            hh[3] = hh[3] &+ D
+        }
+        var result = [UInt8]()
+        result.reserveCapacity(hh.count / 4)
+
+        hh.forEach {
+            let itemLE = $0.littleEndian
+            let r1 = UInt8(itemLE & 0xff)
+            let r2 = UInt8((itemLE >> 8) & 0xff)
+            let r3 = UInt8((itemLE >> 16) & 0xff)
+            let r4 = UInt8((itemLE >> 24) & 0xff)
+            result += [r1, r2, r3, r4]
+        }
+        return result
+    }
+}

Pods/Kingfisher/Sources/Views/AnimatedImageView.swift

@@ -0,0 +1,732 @@
+//
+//  AnimatableImageView.swift
+//  Kingfisher
+//
+//  Created by bl4ckra1sond3tre on 4/22/16.
+//
+//  The AnimatableImageView, AnimatedFrame and Animator is a modified version of 
+//  some classes from kaishin's Gifu project (https://github.com/kaishin/Gifu)
+//
+//  The MIT License (MIT)
+//
+//  Copyright (c) 2019 Reda Lemeden.
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy of
+//  this software and associated documentation files (the "Software"), to deal in
+//  the Software without restriction, including without limitation the rights to
+//  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+//  the Software, and to permit persons to whom the Software is furnished to do so,
+//  subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+//  FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+//  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+//  IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+//  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+//  The name and characters used in the demo of this software are property of their
+//  respective owners.
+
+#if !os(watchOS)
+#if canImport(UIKit)
+import UIKit
+import ImageIO
+
+/// Protocol of `AnimatedImageView`.
+public protocol AnimatedImageViewDelegate: AnyObject {
+
+    /// Called after the animatedImageView has finished each animation loop.
+    ///
+    /// - Parameters:
+    ///   - imageView: The `AnimatedImageView` that is being animated.
+    ///   - count: The looped count.
+    func animatedImageView(_ imageView: AnimatedImageView, didPlayAnimationLoops count: UInt)
+
+    /// Called after the `AnimatedImageView` has reached the max repeat count.
+    ///
+    /// - Parameter imageView: The `AnimatedImageView` that is being animated.
+    func animatedImageViewDidFinishAnimating(_ imageView: AnimatedImageView)
+}
+
+extension AnimatedImageViewDelegate {
+    public func animatedImageView(_ imageView: AnimatedImageView, didPlayAnimationLoops count: UInt) {}
+    public func animatedImageViewDidFinishAnimating(_ imageView: AnimatedImageView) {}
+}
+
+let KFRunLoopModeCommon = RunLoop.Mode.common
+
+/// Represents a subclass of `UIImageView` for displaying animated image.
+/// Different from showing animated image in a normal `UIImageView` (which load all frames at one time),
+/// `AnimatedImageView` only tries to load several frames (defined by `framePreloadCount`) to reduce memory usage.
+/// It provides a tradeoff between memory usage and CPU time. If you have a memory issue when using a normal image
+/// view to load GIF data, you could give this class a try.
+///
+/// Kingfisher supports setting GIF animated data to either `UIImageView` and `AnimatedImageView` out of box. So
+/// it would be fairly easy to switch between them.
+open class AnimatedImageView: UIImageView {
+    /// Proxy object for preventing a reference cycle between the `CADDisplayLink` and `AnimatedImageView`.
+    class TargetProxy {
+        private weak var target: AnimatedImageView?
+        
+        init(target: AnimatedImageView) {
+            self.target = target
+        }
+        
+        @objc func onScreenUpdate() {
+            target?.updateFrameIfNeeded()
+        }
+    }
+
+    /// Enumeration that specifies repeat count of GIF
+    public enum RepeatCount: Equatable {
+        case once
+        case finite(count: UInt)
+        case infinite
+
+        public static func ==(lhs: RepeatCount, rhs: RepeatCount) -> Bool {
+            switch (lhs, rhs) {
+            case let (.finite(l), .finite(r)):
+                return l == r
+            case (.once, .once),
+                 (.infinite, .infinite):
+                return true
+            case (.once, .finite(let count)),
+                 (.finite(let count), .once):
+                return count == 1
+            case (.once, _),
+                 (.infinite, _),
+                 (.finite, _):
+                return false
+            }
+        }
+    }
+    
+    // MARK: - Public property
+    /// Whether automatically play the animation when the view become visible. Default is `true`.
+    public var autoPlayAnimatedImage = true
+    
+    /// The count of the frames should be preloaded before shown.
+    public var framePreloadCount = 10
+    
+    /// Specifies whether the GIF frames should be pre-scaled to the image view's size or not.
+    /// If the downloaded image is larger than the image view's size, it will help to reduce some memory use.
+    /// Default is `true`.
+    public var needsPrescaling = true
+
+    /// Decode the GIF frames in background thread before using. It will decode frames data and do a off-screen
+    /// rendering to extract pixel information in background. This can reduce the main thread CPU usage.
+    public var backgroundDecode = true
+
+    /// The animation timer's run loop mode. Default is `RunLoop.Mode.common`.
+    /// Set this property to `RunLoop.Mode.default` will make the animation pause during UIScrollView scrolling.
+    public var runLoopMode = KFRunLoopModeCommon {
+        willSet {
+            guard runLoopMode != newValue else { return }
+            stopAnimating()
+            displayLink.remove(from: .main, forMode: runLoopMode)
+            displayLink.add(to: .main, forMode: newValue)
+            startAnimating()
+        }
+    }
+    
+    /// The repeat count. The animated image will keep animate until it the loop count reaches this value.
+    /// Setting this value to another one will reset current animation.
+    ///
+    /// Default is `.infinite`, which means the animation will last forever.
+    public var repeatCount = RepeatCount.infinite {
+        didSet {
+            if oldValue != repeatCount {
+                reset()
+                setNeedsDisplay()
+                layer.setNeedsDisplay()
+            }
+        }
+    }
+
+    /// Delegate of this `AnimatedImageView` object. See `AnimatedImageViewDelegate` protocol for more.
+    public weak var delegate: AnimatedImageViewDelegate?
+
+    /// The `Animator` instance that holds the frames of a specific image in memory.
+    public private(set) var animator: Animator?
+
+    // MARK: - Private property
+    // Dispatch queue used for preloading images.
+    private lazy var preloadQueue: DispatchQueue = {
+        return DispatchQueue(label: "com.onevcat.Kingfisher.Animator.preloadQueue")
+    }()
+    
+    // A flag to avoid invalidating the displayLink on deinit if it was never created, because displayLink is so lazy.
+    private var isDisplayLinkInitialized: Bool = false
+    
+    // A display link that keeps calling the `updateFrame` method on every screen refresh.
+    private lazy var displayLink: CADisplayLink = {
+        isDisplayLinkInitialized = true
+        let displayLink = CADisplayLink(target: TargetProxy(target: self), selector: #selector(TargetProxy.onScreenUpdate))
+        displayLink.add(to: .main, forMode: runLoopMode)
+        displayLink.isPaused = true
+        return displayLink
+    }()
+    
+    // MARK: - Override
+    override open var image: KFCrossPlatformImage? {
+        didSet {
+            if image != oldValue {
+                reset()
+            }
+            setNeedsDisplay()
+            layer.setNeedsDisplay()
+        }
+    }
+    
+    open override var isHighlighted: Bool {
+        get {
+            super.isHighlighted
+        }
+        set {
+            // Highlighted image is unsupported for animated images.
+            // See https://github.com/onevcat/Kingfisher/issues/1679
+            if displayLink.isPaused {
+                super.isHighlighted = newValue
+            }
+        }
+    }
+
+// Workaround for Apple xcframework creating issue on Apple TV in Swift 5.8.
+// https://github.com/apple/swift/issues/66015
+#if os(tvOS)
+    public override init(image: UIImage?, highlightedImage: UIImage?) {
+        super.init(image: image, highlightedImage: highlightedImage)
+    }
+    
+    required public init?(coder: NSCoder) {
+        super.init(coder: coder)
+    }
+    
+    init() {
+        super.init(frame: .zero)
+    }
+#endif
+    
+    deinit {
+        if isDisplayLinkInitialized {
+            displayLink.invalidate()
+        }
+    }
+    
+    override open var isAnimating: Bool {
+        if isDisplayLinkInitialized {
+            return !displayLink.isPaused
+        } else {
+            return super.isAnimating
+        }
+    }
+    
+    /// Starts the animation.
+    override open func startAnimating() {
+        guard !isAnimating else { return }
+        guard let animator = animator else { return }
+        guard !animator.isReachMaxRepeatCount else { return }
+
+        displayLink.isPaused = false
+    }
+    
+    /// Stops the animation.
+    override open func stopAnimating() {
+        super.stopAnimating()
+        if isDisplayLinkInitialized {
+            displayLink.isPaused = true
+        }
+    }
+    
+    override open func display(_ layer: CALayer) {
+        layer.contents = animator?.currentFrameImage?.cgImage ?? image?.cgImage
+    }
+    
+    override open func didMoveToWindow() {
+        super.didMoveToWindow()
+        didMove()
+    }
+    
+    override open func didMoveToSuperview() {
+        super.didMoveToSuperview()
+        didMove()
+    }
+
+    // This is for back compatibility that using regular `UIImageView` to show animated image.
+    override func shouldPreloadAllAnimation() -> Bool {
+        return false
+    }
+
+    // Reset the animator.
+    private func reset() {
+        animator = nil
+        if let image = image, let frameSource = image.kf.frameSource {
+            #if os(visionOS)
+            let targetSize = bounds.scaled(UITraitCollection.current.displayScale).size
+            #else
+            var scale: CGFloat = 0
+            
+            if #available(iOS 13.0, tvOS 13.0, *) {
+                scale = UITraitCollection.current.displayScale
+            } else {
+                scale = UIScreen.main.scale
+            }
+            let targetSize = bounds.scaled(scale).size
+            #endif
+            let animator = Animator(
+                frameSource: frameSource,
+                contentMode: contentMode,
+                size: targetSize,
+                imageSize: image.kf.size,
+                imageScale: image.kf.scale,
+                framePreloadCount: framePreloadCount,
+                repeatCount: repeatCount,
+                preloadQueue: preloadQueue)
+            animator.delegate = self
+            animator.needsPrescaling = needsPrescaling
+            animator.backgroundDecode = backgroundDecode
+            animator.prepareFramesAsynchronously()
+            self.animator = animator
+        }
+        didMove()
+    }
+    
+    private func didMove() {
+        if autoPlayAnimatedImage && animator != nil {
+            if let _ = superview, let _ = window {
+                startAnimating()
+            } else {
+                stopAnimating()
+            }
+        }
+    }
+    
+    /// Update the current frame with the displayLink duration.
+    private func updateFrameIfNeeded() {
+        guard let animator = animator else {
+            return
+        }
+
+        guard !animator.isFinished else {
+            stopAnimating()
+            delegate?.animatedImageViewDidFinishAnimating(self)
+            return
+        }
+
+        let duration: CFTimeInterval
+
+        // CA based display link is opt-out from ProMotion by default.
+        // So the duration and its FPS might not match. 
+        // See [#718](https://github.com/onevcat/Kingfisher/issues/718)
+        // By setting CADisableMinimumFrameDuration to YES in Info.plist may
+        // cause the preferredFramesPerSecond being 0
+        let preferredFramesPerSecond = displayLink.preferredFramesPerSecond
+        if preferredFramesPerSecond == 0 {
+            duration = displayLink.duration
+        } else {
+            // Some devices (like iPad Pro 10.5) will have a different FPS.
+            duration = 1.0 / TimeInterval(preferredFramesPerSecond)
+        }
+
+        animator.shouldChangeFrame(with: duration) { [weak self] hasNewFrame in
+            if hasNewFrame {
+                self?.layer.setNeedsDisplay()
+            }
+        }
+    }
+}
+
+protocol AnimatorDelegate: AnyObject {
+    func animator(_ animator: AnimatedImageView.Animator, didPlayAnimationLoops count: UInt)
+}
+
+extension AnimatedImageView: AnimatorDelegate {
+    func animator(_ animator: Animator, didPlayAnimationLoops count: UInt) {
+        delegate?.animatedImageView(self, didPlayAnimationLoops: count)
+    }
+}
+
+extension AnimatedImageView {
+
+    // Represents a single frame in a GIF.
+    struct AnimatedFrame {
+
+        // The image to display for this frame. Its value is nil when the frame is removed from the buffer.
+        let image: UIImage?
+
+        // The duration that this frame should remain active.
+        let duration: TimeInterval
+
+        // A placeholder frame with no image assigned.
+        // Used to replace frames that are no longer needed in the animation.
+        var placeholderFrame: AnimatedFrame {
+            return AnimatedFrame(image: nil, duration: duration)
+        }
+
+        // Whether this frame instance contains an image or not.
+        var isPlaceholder: Bool {
+            return image == nil
+        }
+
+        // Returns a new instance from an optional image.
+        //
+        // - parameter image: An optional `UIImage` instance to be assigned to the new frame.
+        // - returns: An `AnimatedFrame` instance.
+        func makeAnimatedFrame(image: UIImage?) -> AnimatedFrame {
+            return AnimatedFrame(image: image, duration: duration)
+        }
+    }
+}
+
+extension AnimatedImageView {
+
+    // MARK: - Animator
+
+    /// An animator which used to drive the data behind `AnimatedImageView`.
+    public class Animator {
+        private let size: CGSize
+
+        private let imageSize: CGSize
+        private let imageScale: CGFloat
+
+        /// The maximum count of image frames that needs preload.
+        public let maxFrameCount: Int
+
+        private let frameSource: ImageFrameSource
+        private let maxRepeatCount: RepeatCount
+
+        private let maxTimeStep: TimeInterval = 1.0
+        private let animatedFrames = SafeArray<AnimatedFrame>()
+        private var frameCount = 0
+        private var timeSinceLastFrameChange: TimeInterval = 0.0
+        private var currentRepeatCount: UInt = 0
+
+        var isFinished: Bool = false
+
+        var needsPrescaling = true
+
+        var backgroundDecode = true
+
+        weak var delegate: AnimatorDelegate?
+
+        // Total duration of one animation loop
+        var loopDuration: TimeInterval = 0
+
+        /// The image of the current frame.
+        public var currentFrameImage: UIImage? {
+            return frame(at: currentFrameIndex)
+        }
+
+        /// The duration of the current active frame duration.
+        public var currentFrameDuration: TimeInterval {
+            return duration(at: currentFrameIndex)
+        }
+
+        /// The index of the current animation frame.
+        public internal(set) var currentFrameIndex = 0 {
+            didSet {
+                previousFrameIndex = oldValue
+            }
+        }
+
+        var previousFrameIndex = 0 {
+            didSet {
+                preloadQueue.async {
+                    self.updatePreloadedFrames()
+                }
+            }
+        }
+
+        var isReachMaxRepeatCount: Bool {
+            switch maxRepeatCount {
+            case .once:
+                return currentRepeatCount >= 1
+            case .finite(let maxCount):
+                return currentRepeatCount >= maxCount
+            case .infinite:
+                return false
+            }
+        }
+
+        /// Whether the current frame is the last frame or not in the animation sequence.
+        public var isLastFrame: Bool {
+            return currentFrameIndex == frameCount - 1
+        }
+
+        var preloadingIsNeeded: Bool {
+            return maxFrameCount < frameCount - 1
+        }
+
+        var contentMode = UIView.ContentMode.scaleToFill
+
+        private lazy var preloadQueue: DispatchQueue = {
+            return DispatchQueue(label: "com.onevcat.Kingfisher.Animator.preloadQueue")
+        }()
+
+        /// Creates an animator with image source reference.
+        ///
+        /// - Parameters:
+        ///   - source: The reference of animated image.
+        ///   - mode: Content mode of the `AnimatedImageView`.
+        ///   - size: Size of the `AnimatedImageView`.
+        ///   - imageSize: Size of the `KingfisherWrapper`.
+        ///   - imageScale: Scale of the `KingfisherWrapper`.
+        ///   - count: Count of frames needed to be preloaded.
+        ///   - repeatCount: The repeat count should this animator uses.
+        ///   - preloadQueue: Dispatch queue used for preloading images.
+        convenience init(imageSource source: CGImageSource,
+                         contentMode mode: UIView.ContentMode,
+                         size: CGSize,
+                         imageSize: CGSize,
+                         imageScale: CGFloat,
+                         framePreloadCount count: Int,
+                         repeatCount: RepeatCount,
+                         preloadQueue: DispatchQueue) {
+            let frameSource = CGImageFrameSource(data: nil, imageSource: source, options: nil)
+            self.init(frameSource: frameSource,
+                      contentMode: mode,
+                      size: size,
+                      imageSize: imageSize,
+                      imageScale: imageScale,
+                      framePreloadCount: count,
+                      repeatCount: repeatCount,
+                      preloadQueue: preloadQueue)
+        }
+        
+        /// Creates an animator with a custom image frame source.
+        ///
+        /// - Parameters:
+        ///   - frameSource: The reference of animated image.
+        ///   - mode: Content mode of the `AnimatedImageView`.
+        ///   - size: Size of the `AnimatedImageView`.
+        ///   - imageSize: Size of the `KingfisherWrapper`.
+        ///   - imageScale: Scale of the `KingfisherWrapper`.
+        ///   - count: Count of frames needed to be preloaded.
+        ///   - repeatCount: The repeat count should this animator uses.
+        ///   - preloadQueue: Dispatch queue used for preloading images.
+        init(frameSource source: ImageFrameSource,
+             contentMode mode: UIView.ContentMode,
+             size: CGSize,
+             imageSize: CGSize,
+             imageScale: CGFloat,
+             framePreloadCount count: Int,
+             repeatCount: RepeatCount,
+             preloadQueue: DispatchQueue) {
+            self.frameSource = source
+            self.contentMode = mode
+            self.size = size
+            self.imageSize = imageSize
+            self.imageScale = imageScale
+            self.maxFrameCount = count
+            self.maxRepeatCount = repeatCount
+            self.preloadQueue = preloadQueue
+            
+            GraphicsContext.begin(size: imageSize, scale: imageScale)
+        }
+        
+        deinit {
+            resetAnimatedFrames()
+            GraphicsContext.end()
+        }
+
+        /// Gets the image frame of a given index.
+        /// - Parameter index: The index of desired image.
+        /// - Returns: The decoded image at the frame. `nil` if the index is out of bound or the image is not yet loaded.
+        public func frame(at index: Int) -> KFCrossPlatformImage? {
+            return animatedFrames[index]?.image
+        }
+
+        public func duration(at index: Int) -> TimeInterval {
+            return animatedFrames[index]?.duration  ?? .infinity
+        }
+
+        func prepareFramesAsynchronously() {
+            frameCount = frameSource.frameCount
+            animatedFrames.reserveCapacity(frameCount)
+            preloadQueue.async { [weak self] in
+                self?.setupAnimatedFrames()
+            }
+        }
+
+        func shouldChangeFrame(with duration: CFTimeInterval, handler: (Bool) -> Void) {
+            incrementTimeSinceLastFrameChange(with: duration)
+
+            if currentFrameDuration > timeSinceLastFrameChange {
+                handler(false)
+            } else {
+                resetTimeSinceLastFrameChange()
+                incrementCurrentFrameIndex()
+                handler(true)
+            }
+        }
+
+        private func setupAnimatedFrames() {
+            resetAnimatedFrames()
+
+            var duration: TimeInterval = 0
+
+            (0..<frameCount).forEach { index in
+                let frameDuration = frameSource.duration(at: index)
+                duration += min(frameDuration, maxTimeStep)
+                animatedFrames.append(AnimatedFrame(image: nil, duration: frameDuration))
+
+                if index > maxFrameCount { return }
+                animatedFrames[index] = animatedFrames[index]?.makeAnimatedFrame(image: loadFrame(at: index))
+            }
+
+            self.loopDuration = duration
+        }
+
+        private func resetAnimatedFrames() {
+            animatedFrames.removeAll()
+        }
+
+        private func loadFrame(at index: Int) -> UIImage? {
+            let resize = needsPrescaling && size != .zero
+            let maxSize = resize ? size : nil
+            guard let cgImage = frameSource.frame(at: index, maxSize: maxSize) else {
+                return nil
+            }
+            
+            if #available(iOS 15, tvOS 15, *) {
+                // From iOS 15, a plain image loading causes iOS calling `-[_UIImageCGImageContent initWithCGImage:scale:]`
+                // in ImageIO, which holds the image ref on the creating thread.
+                // To get a workaround, create another image ref and use that to create the final image. This leads to
+                // some performance loss, but there is little we can do.
+                // https://github.com/onevcat/Kingfisher/issues/1844
+                guard let context = GraphicsContext.current(size: imageSize, scale: imageScale, inverting: true, cgImage: cgImage),
+                      let decodedImageRef = cgImage.decoded(on: context, scale: imageScale)
+                else {
+                    return KFCrossPlatformImage(cgImage: cgImage)
+                }
+                
+                return KFCrossPlatformImage(cgImage: decodedImageRef)
+            } else {
+                let image = KFCrossPlatformImage(cgImage: cgImage)
+                if backgroundDecode {
+                    guard let context = GraphicsContext.current(size: imageSize, scale: imageScale, inverting: true, cgImage: cgImage) else {
+                        return image
+                    }
+                    return image.kf.decoded(on: context)
+                } else {
+                    return image
+                }
+            }
+        }
+        
+        private func updatePreloadedFrames() {
+            guard preloadingIsNeeded else {
+                return
+            }
+
+            let previousFrame = animatedFrames[previousFrameIndex]
+            animatedFrames[previousFrameIndex] = previousFrame?.placeholderFrame
+            // ensure the image dealloc in main thread
+            defer {
+                if let image = previousFrame?.image {
+                    DispatchQueue.main.async {
+                        _ = image
+                    }
+                }
+            }
+
+            preloadIndexes(start: currentFrameIndex).forEach { index in
+                guard let currentAnimatedFrame = animatedFrames[index] else { return }
+                if !currentAnimatedFrame.isPlaceholder { return }
+                animatedFrames[index] = currentAnimatedFrame.makeAnimatedFrame(image: loadFrame(at: index))
+            }
+        }
+
+        private func incrementCurrentFrameIndex() {
+            let wasLastFrame = isLastFrame
+            currentFrameIndex = increment(frameIndex: currentFrameIndex)
+            if isLastFrame {
+                currentRepeatCount += 1
+                if isReachMaxRepeatCount {
+                    isFinished = true
+
+                    // Notify the delegate here because the animation is stopping.
+                    delegate?.animator(self, didPlayAnimationLoops: currentRepeatCount)
+                }
+            } else if wasLastFrame {
+
+                // Notify the delegate that the loop completed
+                delegate?.animator(self, didPlayAnimationLoops: currentRepeatCount)
+            }
+        }
+
+        private func incrementTimeSinceLastFrameChange(with duration: TimeInterval) {
+            timeSinceLastFrameChange += min(maxTimeStep, duration)
+        }
+
+        private func resetTimeSinceLastFrameChange() {
+            timeSinceLastFrameChange -= currentFrameDuration
+        }
+
+        private func increment(frameIndex: Int, by value: Int = 1) -> Int {
+            return (frameIndex + value) % frameCount
+        }
+
+        private func preloadIndexes(start index: Int) -> [Int] {
+            let nextIndex = increment(frameIndex: index)
+            let lastIndex = increment(frameIndex: index, by: maxFrameCount)
+
+            if lastIndex >= nextIndex {
+                return [Int](nextIndex...lastIndex)
+            } else {
+                return [Int](nextIndex..<frameCount) + [Int](0...lastIndex)
+            }
+        }
+    }
+}
+
+class SafeArray<Element> {
+    private var array: Array<Element> = []
+    private let lock = NSLock()
+    
+    subscript(index: Int) -> Element? {
+        get {
+            lock.lock()
+            defer { lock.unlock() }
+            return array.indices ~= index ? array[index] : nil
+        }
+        
+        set {
+            lock.lock()
+            defer { lock.unlock() }
+            if let newValue = newValue, array.indices ~= index {
+                array[index] = newValue
+            }
+        }
+    }
+    
+    var count : Int {
+        lock.lock()
+        defer { lock.unlock() }
+        return array.count
+    }
+    
+    func reserveCapacity(_ count: Int) {
+        lock.lock()
+        defer { lock.unlock() }
+        array.reserveCapacity(count)
+    }
+    
+    func append(_ element: Element) {
+        lock.lock()
+        defer { lock.unlock() }
+        array += [element]
+    }
+    
+    func removeAll() {
+        lock.lock()
+        defer { lock.unlock() }
+        array = []
+    }
+}
+#endif
+#endif

Pods/Kingfisher/Sources/Views/Indicator.swift

@@ -0,0 +1,233 @@
+//
+//  Indicator.swift
+//  Kingfisher
+//
+//  Created by João D. Moreira on 30/08/16.
+//
+//  Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+#if !os(watchOS)
+
+#if canImport(AppKit) && !targetEnvironment(macCatalyst)
+import AppKit
+public typealias IndicatorView = NSView
+#else
+import UIKit
+public typealias IndicatorView = UIView
+#endif
+
+/// Represents the activity indicator type which should be added to
+/// an image view when an image is being downloaded.
+///
+/// - none: No indicator.
+/// - activity: Uses the system activity indicator.
+/// - image: Uses an image as indicator. GIF is supported.
+/// - custom: Uses a custom indicator. The type of associated value should conform to the `Indicator` protocol.
+public enum IndicatorType {
+    /// No indicator.
+    case none
+    /// Uses the system activity indicator.
+    case activity
+    /// Uses an image as indicator. GIF is supported.
+    case image(imageData: Data)
+    /// Uses a custom indicator. The type of associated value should conform to the `Indicator` protocol.
+    case custom(indicator: Indicator)
+}
+
+/// An indicator type which can be used to show the download task is in progress.
+public protocol Indicator {
+    
+    /// Called when the indicator should start animating.
+    func startAnimatingView()
+    
+    /// Called when the indicator should stop animating.
+    func stopAnimatingView()
+
+    /// Center offset of the indicator. Kingfisher will use this value to determine the position of
+    /// indicator in the super view.
+    var centerOffset: CGPoint { get }
+    
+    /// The indicator view which would be added to the super view.
+    var view: IndicatorView { get }
+
+    /// The size strategy used when adding the indicator to image view.
+    /// - Parameter imageView: The super view of indicator.
+    func sizeStrategy(in imageView: KFCrossPlatformImageView) -> IndicatorSizeStrategy
+}
+
+public enum IndicatorSizeStrategy {
+    case intrinsicSize
+    case full
+    case size(CGSize)
+}
+
+extension Indicator {
+    
+    /// Default implementation of `centerOffset` of `Indicator`. The default value is `.zero`, means that there is
+    /// no offset for the indicator view.
+    public var centerOffset: CGPoint { return .zero }
+
+    /// Default implementation of `centerOffset` of `Indicator`. The default value is `.full`, means that the indicator
+    /// will pin to the same height and width as the image view.
+    public func sizeStrategy(in imageView: KFCrossPlatformImageView) -> IndicatorSizeStrategy {
+        return .full
+    }
+}
+
+// Displays a NSProgressIndicator / UIActivityIndicatorView
+final class ActivityIndicator: Indicator {
+
+    #if os(macOS)
+    private let activityIndicatorView: NSProgressIndicator
+    #else
+    private let activityIndicatorView: UIActivityIndicatorView
+    #endif
+    private var animatingCount = 0
+
+    var view: IndicatorView {
+        return activityIndicatorView
+    }
+
+    func startAnimatingView() {
+        if animatingCount == 0 {
+            #if os(macOS)
+            activityIndicatorView.startAnimation(nil)
+            #else
+            activityIndicatorView.startAnimating()
+            #endif
+            activityIndicatorView.isHidden = false
+        }
+        animatingCount += 1
+    }
+
+    func stopAnimatingView() {
+        animatingCount = max(animatingCount - 1, 0)
+        if animatingCount == 0 {
+            #if os(macOS)
+                activityIndicatorView.stopAnimation(nil)
+            #else
+                activityIndicatorView.stopAnimating()
+            #endif
+            activityIndicatorView.isHidden = true
+        }
+    }
+
+    func sizeStrategy(in imageView: KFCrossPlatformImageView) -> IndicatorSizeStrategy {
+        return .intrinsicSize
+    }
+
+    init() {
+        #if os(macOS)
+            activityIndicatorView = NSProgressIndicator(frame: CGRect(x: 0, y: 0, width: 16, height: 16))
+            activityIndicatorView.controlSize = .small
+            activityIndicatorView.style = .spinning
+        #else
+            let indicatorStyle: UIActivityIndicatorView.Style
+
+            #if os(tvOS)
+            if #available(tvOS 13.0, *) {
+                indicatorStyle = UIActivityIndicatorView.Style.large
+            } else {
+                indicatorStyle = UIActivityIndicatorView.Style.white
+            }
+            #elseif os(visionOS)
+            indicatorStyle = UIActivityIndicatorView.Style.medium
+            #else
+            if #available(iOS 13.0, * ) {
+                indicatorStyle = UIActivityIndicatorView.Style.medium
+            } else {
+                indicatorStyle = UIActivityIndicatorView.Style.gray
+            }
+            #endif
+
+            activityIndicatorView = UIActivityIndicatorView(style: indicatorStyle)
+        #endif
+    }
+}
+
+#if canImport(UIKit)
+extension UIActivityIndicatorView.Style {
+    #if compiler(>=5.1)
+    #else
+    static let large = UIActivityIndicatorView.Style.white
+    #if !os(tvOS)
+    static let medium = UIActivityIndicatorView.Style.gray
+    #endif
+    #endif
+}
+#endif
+
+// MARK: - ImageIndicator
+// Displays an ImageView. Supports gif
+final class ImageIndicator: Indicator {
+    private let animatedImageIndicatorView: KFCrossPlatformImageView
+
+    var view: IndicatorView {
+        return animatedImageIndicatorView
+    }
+
+    init?(
+        imageData data: Data,
+        processor: ImageProcessor = DefaultImageProcessor.default,
+        options: KingfisherParsedOptionsInfo? = nil)
+    {
+        var options = options ?? KingfisherParsedOptionsInfo(nil)
+        // Use normal image view to show animations, so we need to preload all animation data.
+        if !options.preloadAllAnimationData {
+            options.preloadAllAnimationData = true
+        }
+        
+        guard let image = processor.process(item: .data(data), options: options) else {
+            return nil
+        }
+
+        animatedImageIndicatorView = KFCrossPlatformImageView()
+        animatedImageIndicatorView.image = image
+        
+        #if os(macOS)
+            // Need for gif to animate on macOS
+            animatedImageIndicatorView.imageScaling = .scaleNone
+            animatedImageIndicatorView.canDrawSubviewsIntoLayer = true
+        #else
+            animatedImageIndicatorView.contentMode = .center
+        #endif
+    }
+
+    func startAnimatingView() {
+        #if os(macOS)
+            animatedImageIndicatorView.animates = true
+        #else
+            animatedImageIndicatorView.startAnimating()
+        #endif
+        animatedImageIndicatorView.isHidden = false
+    }
+
+    func stopAnimatingView() {
+        #if os(macOS)
+            animatedImageIndicatorView.animates = false
+        #else
+            animatedImageIndicatorView.stopAnimating()
+        #endif
+        animatedImageIndicatorView.isHidden = true
+    }
+}
+
+#endif

Pods/Manifest.lock

@@ -0,0 +1,32 @@
+PODS:
+  - BigInt (5.2.0)
+  - Kingfisher (7.10.0)
+  - SwiftProtobuf (1.25.1)
+  - TrustWalletCore (4.0.8):
+    - TrustWalletCore/Core (= 4.0.8)
+  - TrustWalletCore/Core (4.0.8):
+    - TrustWalletCore/Types
+  - TrustWalletCore/Types (4.0.8):
+    - SwiftProtobuf
+
+DEPENDENCIES:
+  - BigInt
+  - Kingfisher
+  - TrustWalletCore
+
+SPEC REPOS:
+  trunk:
+    - BigInt
+    - Kingfisher
+    - SwiftProtobuf
+    - TrustWalletCore
+
+SPEC CHECKSUMS:
+  BigInt: f668a80089607f521586bbe29513d708491ef2f7
+  Kingfisher: a18f05d3b6d37d8650ee4a3e61d57a28fc6207f6
+  SwiftProtobuf: 69f02cd54fb03201c5e6bf8b76f687c5ef7541a3
+  TrustWalletCore: 1c544d540c37dff1fd7068aa11c06558d0c9e8de
+
+PODFILE CHECKSUM: 0f310e1fc0a68af5ddad91584de979217a389c13
+
+COCOAPODS: 1.13.0

Pods/SwiftProtobuf/LICENSE.txt

@@ -0,0 +1,211 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+    TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+    1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+    2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+    3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+    4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+    5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+    6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+    7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+    8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+    9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+    END OF TERMS AND CONDITIONS
+
+    APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+    Copyright [yyyy] [name of copyright owner]
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+
+   
+   
+## Runtime Library Exception to the Apache 2.0 License: ##
+
+
+    As an exception, if you use this Software to compile your source code and
+    portions of this Software are embedded into the binary product as a result,
+    you may redistribute such product without providing attribution as would
+    otherwise be required by Sections 4(a), 4(b) and 4(d) of the License.

Pods/SwiftProtobuf/README.md

@@ -0,0 +1,303 @@
+<img src="https://swift.org/assets/images/swift.svg" alt="Swift logo" height="70" >
+
+# Swift Protobuf
+
+**Welcome to Swift Protobuf!**
+
+[Apple's Swift programming language](https://swift.org/) is a perfect
+complement to [Google's Protocol
+Buffer](https://developers.google.com/protocol-buffers/) ("protobuf") serialization
+technology.
+They both emphasize high performance and programmer safety.
+
+This project provides both the command-line program that adds Swift
+code generation to Google's `protoc` and the runtime library that is
+necessary for using the generated code.
+After using the protoc plugin to generate Swift code from your .proto
+files, you will need to add this library to your project.
+
+[![Build and Test](https://github.com/apple/swift-protobuf/workflows/Build%20and%20Test/badge.svg)](https://github.com/apple/swift-protobuf/actions?query=workflow%3A%22Build+and+Test%22)
+[![Check Upstream Protos](https://github.com/apple/swift-protobuf/workflows/Check%20Upstream%20Proto%20Files/badge.svg)](https://github.com/apple/swift-protobuf/actions?query=workflow%3A%22Check+Upstream+Proto+Files%22)
+[![Run Conformance Tests](https://github.com/apple/swift-protobuf/workflows/Run%20Conformance%20Tests/badge.svg)](https://github.com/apple/swift-protobuf/actions?query=workflow%3A%22Run+Conformance+Tests%22)
+
+# Features of SwiftProtobuf
+
+SwiftProtobuf offers many advantages over alternative serialization
+systems:
+
+* Safety: The protobuf code-generation system avoids the
+  errors that are common with hand-built serialization code.
+* Correctness: SwiftProtobuf passes both its own extensive
+  test suite and Google's full conformance test for protobuf
+  correctness.
+* Schema-driven: Defining your data structures in a separate
+  `.proto` schema file clearly documents your communications
+  conventions.
+* Idiomatic: SwiftProtobuf takes full advantage of the Swift language.
+  In particular, all generated types provide full Swift copy-on-write
+  value semantics.
+* Efficient binary serialization: The `.serializedData()`
+  method returns a `Data` with a compact binary form of your data.
+  You can deserialize the data using the `init(serializedData:)`
+  initializer.
+* Standard JSON serialization: The `.jsonUTF8Data()` method returns a JSON
+  form of your data that can be parsed with the `init(jsonUTF8Data:)`
+  initializer.
+* Hashable, Equatable: The generated struct can be put into a
+  `Set<>` or `Dictionary<>`.
+* Performant: The binary and JSON serializers have been
+  extensively optimized.
+* Extensible: You can add your own Swift extensions to any
+  of the generated types.
+
+Best of all, you can take the same `.proto` file and generate
+Java, C++, Python, or Objective-C for use on other platforms. The
+generated code for those languages will use the exact same
+serialization and deserialization conventions as SwiftProtobuf, making
+it easy to exchange serialized data in binary or JSON forms, with no
+additional effort on your part.
+
+# Documentation
+
+More information is available in the associated documentation:
+
+ * [Google's protobuf documentation](https://developers.google.com/protocol-buffers/)
+   provides general information about protocol buffers, the protoc compiler,
+   and how to use protocol buffers with C++, Java, and other languages.
+ * [PLUGIN.md](Documentation/PLUGIN.md) documents the `protoc-gen-swift`
+   plugin that adds Swift support to the `protoc` program
+ * [API.md](Documentation/API.md) documents how to use the generated code.
+   This is recommended reading for anyone using SwiftProtobuf in their
+   project.
+ * [cocoadocs.org](http://cocoadocs.org/docsets/SwiftProtobuf/) has the generated
+   API documentation
+ * [INTERNALS.md](Documentation/INTERNALS.md) documents the internal structure
+   of the generated code and the library.  This
+   should only be needed by folks interested in working on SwiftProtobuf
+   itself.
+ * [STYLE_GUIDELINES.md](Documentation/STYLE_GUIDELINES.md) documents the style
+   guidelines we have adopted in our codebase if you are interested in
+   contributing
+
+# Getting Started
+
+If you've worked with Protocol Buffers before, adding Swift support is very
+simple: you just need to build the `protoc-gen-swift` program and copy it into
+your PATH.
+The `protoc` program will find and use it automatically, allowing you
+to build Swift sources for your proto files.
+You will also, of course, need to add the SwiftProtobuf runtime library to
+your project as explained below.
+
+## System Requirements
+
+To use Swift with Protocol buffers, you'll need:
+
+* A Swift 4.2 or later compiler (Xcode 10.0 or later).  Support is included
+for the Swift Package Manager; or using the included Xcode project. The Swift
+protobuf project is being developed and tested against the latest release
+version of Swift available from [Swift.org](https://swift.org)
+
+* Google's protoc compiler.  The Swift protoc plugin is being actively
+developed and tested against the latest protobuf sources.
+The SwiftProtobuf tests need a version of protoc which supports the
+`swift_prefix` option (introduced in protoc 3.2.0).
+It may work with earlier versions of protoc.
+You can get recent versions from
+[Google's github repository](https://github.com/protocolbuffers/protobuf).
+
+## Building and Installing the Code Generator Plugin
+
+To translate `.proto` files into Swift, you will need both Google's
+protoc compiler and the SwiftProtobuf code generator plugin.
+
+Building the plugin should be simple on any supported Swift platform:
+
+```
+$ git clone https://github.com/apple/swift-protobuf.git
+$ cd swift-protobuf
+```
+
+Pick what released version of SwiftProtobuf you are going to use.  You can get
+a list of tags with:
+
+```
+$ git tag -l
+```
+
+Once you pick the version you will use, set your local state to match, and
+build the protoc plugin:
+
+```
+$ git checkout tags/[tag_name]
+$ swift build -c release
+```
+
+This will create a binary called `protoc-gen-swift` in the `.build/release`
+directory.
+
+To install, just copy this one executable into a directory that is
+part of your `PATH` environment variable.
+
+NOTE: The Swift runtime support is now included with macOS. If you are
+using old Xcode versions or are on older system versions, you might need
+to use also use `--static-swift-stdlib` with `swift build`.
+
+### Alternatively install via Homebrew
+
+If you prefer using [Homebrew](https://brew.sh):
+
+```
+$ brew install swift-protobuf
+```
+
+This will install `protoc` compiler and Swift code generator plugin.
+
+## Converting .proto files into Swift
+
+To generate Swift output for your .proto files, you run the `protoc` command as
+usual, using the `--swift_out=<directory>` option:
+
+```
+$ protoc --swift_out=. my.proto
+```
+
+The `protoc` program will automatically look for `protoc-gen-swift` in your
+`PATH` and use it.
+
+Each `.proto` input file will get translated to a corresponding `.pb.swift`
+file in the output directory.
+
+More information about building and using `protoc-gen-swift` can be found
+in the [detailed Plugin documentation](Documentation/PLUGIN.md).
+
+## Adding the SwiftProtobuf library to your project...
+
+To use the generated code, you need to include the `SwiftProtobuf` library
+module in your project.  How you do this will vary depending on how
+you're building your project.  Note that in all cases, we strongly recommend
+that you use the version of the SwiftProtobuf library that corresponds to
+the version of `protoc-gen-swift` you used to generate the code.
+
+### ...using `swift build`
+
+After copying the `.pb.swift` files into your project, you will need to add the
+[SwiftProtobuf library](https://github.com/apple/swift-protobuf) to your
+project to support the generated code.
+If you are using the Swift Package Manager, add a dependency to your
+`Package.swift` file and import the `SwiftProtobuf` library into the desired
+targets.  Adjust the `"1.6.0"` here to match the `[tag_name]` you used to build
+the plugin above:
+
+```swift
+dependencies: [
+    .package(name: "SwiftProtobuf", url: "https://github.com/apple/swift-protobuf.git", from: "1.6.0"),
+],
+targets: [
+    .target(name: "MyTarget", dependencies: ["SwiftProtobuf"]),
+]
+```
+
+### ...using Xcode
+
+If you are using Xcode, then you should:
+
+* Add the `.pb.swift` source files generated from your protos directly to your
+  project
+* Add the appropriate `SwiftProtobuf_<platform>` target from the Xcode project
+  in this package to your project.
+
+### ...using CocoaPods
+
+If you're using CocoaPods, add this to your `Podfile` adjusting the `:tag` to
+match the `[tag_name]` you used to build the plugin above:
+
+```ruby
+pod 'SwiftProtobuf', '~> 1.0'
+```
+
+And run `pod install`.
+
+NOTE: CocoaPods 1.7 or newer is required.
+
+### ...using Carthage
+
+If you're using Carthage, add this to your `Cartfile` but adjust the tag to match the `[tag_name]` you used to build the plugin above:
+
+```ruby
+github "apple/swift-protobuf" ~> 1.0
+```
+
+Run `carthage update` and drag `SwiftProtobuf.framework` into your Xcode.project.
+
+# Quick Start
+
+Once you have installed the code generator, used it to
+generate Swift code from your `.proto` file, and
+added the SwiftProtobuf library to your project, you can
+just use the generated types as you would any other Swift
+struct.
+
+For example, you might start with the following very simple
+proto file:
+```protobuf
+syntax = "proto3";
+
+message BookInfo {
+   int64 id = 1;
+   string title = 2;
+   string author = 3;
+}
+```
+
+Then generate Swift code using:
+```
+$ protoc --swift_out=. DataModel.proto
+```
+
+The generated code will expose a Swift property for
+each of the proto fields as well as a selection
+of serialization and deserialization capabilities:
+```swift
+// Create a BookInfo object and populate it:
+var info = BookInfo()
+info.id = 1734
+info.title = "Really Interesting Book"
+info.author = "Jane Smith"
+
+// As above, but generating a read-only value:
+let info2 = BookInfo.with {
+    $0.id = 1735
+    $0.title = "Even More Interesting"
+    $0.author = "Jane Q. Smith"
+  }
+
+// Serialize to binary protobuf format:
+let binaryData: Data = try info.serializedData()
+
+// Deserialize a received Data object from `binaryData`
+let decodedInfo = try BookInfo(serializedData: binaryData)
+
+// Serialize to JSON format as a Data object
+let jsonData: Data = try info.jsonUTF8Data()
+
+// Deserialize from JSON format from `jsonData`
+let receivedFromJSON = try BookInfo(jsonUTF8Data: jsonData)
+```
+
+You can find more information in the detailed
+[API Documentation](Documentation/API.md).
+
+## Report any issues
+
+If you run into problems, please send us a detailed report.
+At a minimum, please include:
+
+* The specific operating system and version (for example, "macOS 10.12.1" or
+  "Ubuntu 16.10")
+* The version of Swift you have installed (from `swift --version`)
+* The version of the protoc compiler you are working with from
+  `protoc --version`
+* The specific version of this source code (you can use `git log -1` to get the
+  latest commit ID)
+* Any local changes you may have

Pods/SwiftProtobuf/Sources/SwiftProtobuf/AnyMessageStorage.swift

@@ -0,0 +1,497 @@
+// Sources/SwiftProtobuf/AnyMessageStorage.swift - Custom storage for Any WKT
+//
+// Copyright (c) 2014 - 2017 Apple Inc. and the project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See LICENSE.txt for license information:
+// https://github.com/apple/swift-protobuf/blob/main/LICENSE.txt
+//
+// -----------------------------------------------------------------------------
+///
+/// Hand written storage class for Google_Protobuf_Any to support on demand
+/// transforms between the formats.
+///
+// -----------------------------------------------------------------------------
+
+import Foundation
+
+#if !swift(>=4.2)
+private let i_2166136261 = Int(bitPattern: 2166136261)
+private let i_16777619 = Int(16777619)
+#endif
+
+fileprivate func serializeAnyJSON(
+  for message: Message,
+  typeURL: String,
+  options: JSONEncodingOptions
+) throws -> String {
+  var visitor = try JSONEncodingVisitor(type: type(of: message), options: options)
+  visitor.startObject(message: message)
+  visitor.encodeField(name: "@type", stringValue: typeURL)
+  if let m = message as? _CustomJSONCodable {
+    let value = try m.encodedJSONString(options: options)
+    visitor.encodeField(name: "value", jsonText: value)
+  } else {
+    try message.traverse(visitor: &visitor)
+  }
+  visitor.endObject()
+  return visitor.stringResult
+}
+
+fileprivate func emitVerboseTextForm(visitor: inout TextFormatEncodingVisitor, message: Message, typeURL: String) {
+  let url: String
+  if typeURL.isEmpty {
+    url = buildTypeURL(forMessage: message, typePrefix: defaultAnyTypeURLPrefix)
+  } else {
+    url = typeURL
+  }
+  visitor.visitAnyVerbose(value: message, typeURL: url)
+}
+
+fileprivate func asJSONObject(body: Data) -> Data {
+  let asciiOpenCurlyBracket = UInt8(ascii: "{")
+  let asciiCloseCurlyBracket = UInt8(ascii: "}")
+  var result = Data([asciiOpenCurlyBracket])
+  result.append(body)
+  result.append(asciiCloseCurlyBracket)
+  return result
+}
+
+fileprivate func unpack(contentJSON: Data,
+                        extensions: ExtensionMap,
+                        options: JSONDecodingOptions,
+                        as messageType: Message.Type) throws -> Message {
+  guard messageType is _CustomJSONCodable.Type else {
+    let contentJSONAsObject = asJSONObject(body: contentJSON)
+    return try messageType.init(jsonUTF8Data: contentJSONAsObject, extensions: extensions, options: options)
+  }
+
+  var value = String()
+  try contentJSON.withUnsafeBytes { (body: UnsafeRawBufferPointer) in
+    if body.count > 0 {
+      // contentJSON will be the valid JSON for inside an object (everything but
+      // the '{' and '}', so minimal validation is needed.
+      var scanner = JSONScanner(source: body, options: options, extensions: extensions)
+      while !scanner.complete {
+        let key = try scanner.nextQuotedString()
+        try scanner.skipRequiredColon()
+        if key == "value" {
+          value = try scanner.skip()
+          break
+        }
+        if !options.ignoreUnknownFields {
+          // The only thing within a WKT should be "value".
+          throw AnyUnpackError.malformedWellKnownTypeJSON
+        }
+        let _ = try scanner.skip()
+        try scanner.skipRequiredComma()
+      }
+      if !options.ignoreUnknownFields && !scanner.complete {
+        // If that wasn't the end, then there was another key, and WKTs should
+        // only have the one when not skipping unknowns.
+        throw AnyUnpackError.malformedWellKnownTypeJSON
+      }
+    }
+  }
+  return try messageType.init(jsonString: value, extensions: extensions, options: options)
+}
+
+internal class AnyMessageStorage {
+  // The two properties generated Google_Protobuf_Any will reference.
+  var _typeURL = String()
+  var _value: Data {
+    // Remapped to the internal `state`.
+    get {
+      switch state {
+      case .binary(let value):
+        return value
+      case .message(let message):
+        do {
+          return try message.serializedData(partial: true)
+        } catch {
+          return Data()
+        }
+      case .contentJSON(let contentJSON, let options):
+        guard let messageType = Google_Protobuf_Any.messageType(forTypeURL: _typeURL) else {
+          return Data()
+        }
+        do {
+          let m = try unpack(contentJSON: contentJSON,
+                             extensions: SimpleExtensionMap(),
+                             options: options,
+                             as: messageType)
+          return try m.serializedData(partial: true)
+        } catch {
+          return Data()
+        }
+      }
+    }
+    set {
+      state = .binary(newValue)
+    }
+  }
+
+  enum InternalState {
+    // a serialized binary
+    // Note: Unlike contentJSON below, binary does not bother to capture the
+    // decoding options. This is because the actual binary format is the binary
+    // blob, i.e. - when decoding from binary, the spec doesn't include decoding
+    // the binary blob, it is pass through. Instead there is a public api for
+    // unpacking that takes new options when a developer decides to decode it.
+    case binary(Data)
+    // a message
+    case message(Message)
+    // parsed JSON with the @type removed and the decoding options.
+    case contentJSON(Data, JSONDecodingOptions)
+  }
+  var state: InternalState = .binary(Data())
+
+  static let defaultInstance = AnyMessageStorage()
+
+  private init() {}
+
+  init(copying source: AnyMessageStorage) {
+    _typeURL = source._typeURL
+    state = source.state
+  }
+
+  func isA<M: Message>(_ type: M.Type) -> Bool {
+    if _typeURL.isEmpty {
+      return false
+    }
+    let encodedType = typeName(fromURL: _typeURL)
+    return encodedType == M.protoMessageName
+  }
+
+  // This is only ever called with the expectation that target will be fully
+  // replaced during the unpacking and never as a merge.
+  func unpackTo<M: Message>(
+    target: inout M,
+    extensions: ExtensionMap?,
+    options: BinaryDecodingOptions
+  ) throws {
+    guard isA(M.self) else {
+      throw AnyUnpackError.typeMismatch
+    }
+
+    switch state {
+    case .binary(let data):
+      target = try M(serializedData: data, extensions: extensions, partial: true, options: options)
+
+    case .message(let msg):
+      if let message = msg as? M {
+        // Already right type, copy it over.
+        target = message
+      } else {
+        // Different type, serialize and parse.
+        let data = try msg.serializedData(partial: true)
+        target = try M(serializedData: data, extensions: extensions, partial: true)
+      }
+
+    case .contentJSON(let contentJSON, let options):
+      target = try unpack(contentJSON: contentJSON,
+                          extensions: extensions ?? SimpleExtensionMap(),
+                          options: options,
+                          as: M.self) as! M
+    }
+  }
+
+  // Called before the message is traversed to do any error preflights.
+  // Since traverse() will use _value, this is our chance to throw
+  // when _value can't.
+  func preTraverse() throws {
+    switch state {
+    case .binary:
+      // Nothing to be checked.
+      break
+
+    case .message:
+      // When set from a developer provided message, partial support
+      // is done. Any message that comes in from another format isn't
+      // checked, and transcoding the isInitialized requirement is
+      // never inserted.
+      break
+
+    case .contentJSON(let contentJSON, let options):
+      // contentJSON requires we have the type available for decoding
+      guard let messageType = Google_Protobuf_Any.messageType(forTypeURL: _typeURL) else {
+          throw BinaryEncodingError.anyTranscodeFailure
+      }
+      do {
+        // Decodes the full JSON and then discard the result.
+        // The regular traversal will decode this again by querying the
+        // `value` field, but that has no way to fail.  As a result,
+        // we need this to accurately handle decode errors.
+        _ = try unpack(contentJSON: contentJSON,
+                       extensions: SimpleExtensionMap(),
+                       options: options,
+                       as: messageType)
+      } catch {
+        throw BinaryEncodingError.anyTranscodeFailure
+      }
+    }
+  }
+}
+
+/// Custom handling for Text format.
+extension AnyMessageStorage {
+  func decodeTextFormat(typeURL url: String, decoder: inout TextFormatDecoder) throws {
+    // Decoding the verbose form requires knowing the type.
+    _typeURL = url
+    guard let messageType = Google_Protobuf_Any.messageType(forTypeURL: url) else {
+      // The type wasn't registered, can't parse it.
+      throw TextFormatDecodingError.malformedText
+    }
+    let terminator = try decoder.scanner.skipObjectStart()
+    var subDecoder = try TextFormatDecoder(messageType: messageType, scanner: decoder.scanner, terminator: terminator)
+    if messageType == Google_Protobuf_Any.self {
+      var any = Google_Protobuf_Any()
+      try any.decodeTextFormat(decoder: &subDecoder)
+      state = .message(any)
+    } else {
+      var m = messageType.init()
+      try m.decodeMessage(decoder: &subDecoder)
+      state = .message(m)
+    }
+    decoder.scanner = subDecoder.scanner
+    if try decoder.nextFieldNumber() != nil {
+      // Verbose any can never have additional keys.
+      throw TextFormatDecodingError.malformedText
+    }
+  }
+
+  // Specialized traverse for writing out a Text form of the Any.
+  // This prefers the more-legible "verbose" format if it can
+  // use it, otherwise will fall back to simpler forms.
+  internal func textTraverse(visitor: inout TextFormatEncodingVisitor) {
+    switch state {
+    case .binary(let valueData):
+      if let messageType = Google_Protobuf_Any.messageType(forTypeURL: _typeURL) {
+        // If we can decode it, we can write the readable verbose form:
+        do {
+          let m = try messageType.init(serializedData: valueData, partial: true)
+          emitVerboseTextForm(visitor: &visitor, message: m, typeURL: _typeURL)
+          return
+        } catch {
+          // Fall through to just print the type and raw binary data
+        }
+      }
+      if !_typeURL.isEmpty {
+        try! visitor.visitSingularStringField(value: _typeURL, fieldNumber: 1)
+      }
+      if !valueData.isEmpty {
+        try! visitor.visitSingularBytesField(value: valueData, fieldNumber: 2)
+      }
+
+    case .message(let msg):
+      emitVerboseTextForm(visitor: &visitor, message: msg, typeURL: _typeURL)
+
+    case .contentJSON(let contentJSON, let options):
+      // If we can decode it, we can write the readable verbose form:
+      if let messageType = Google_Protobuf_Any.messageType(forTypeURL: _typeURL) {
+        do {
+          let m = try unpack(contentJSON: contentJSON,
+                             extensions: SimpleExtensionMap(),
+                             options: options,
+                             as: messageType)
+          emitVerboseTextForm(visitor: &visitor, message: m, typeURL: _typeURL)
+          return
+        } catch {
+          // Fall through to just print the raw JSON data
+        }
+      }
+      if !_typeURL.isEmpty {
+        try! visitor.visitSingularStringField(value: _typeURL, fieldNumber: 1)
+      }
+      // Build a readable form of the JSON:
+      let contentJSONAsObject = asJSONObject(body: contentJSON)
+      visitor.visitAnyJSONDataField(value: contentJSONAsObject)
+    }
+  }
+}
+
+/// The obvious goal for Hashable/Equatable conformance would be for
+/// hash and equality to behave as if we always decoded the inner
+/// object and hashed or compared that.  Unfortunately, Any typically
+/// stores serialized contents and we don't always have the ability to
+/// deserialize it.  Since none of our supported serializations are
+/// fully deterministic, we can't even ensure that equality will
+/// behave this way when the Any contents are in the same
+/// serialization.
+///
+/// As a result, we can only really perform a "best effort" equality
+/// test.  Of course, regardless of the above, we must guarantee that
+/// hashValue is compatible with equality.
+extension AnyMessageStorage {
+#if swift(>=4.2)
+  // Can't use _valueData for a few reasons:
+  // 1. Since decode is done on demand, two objects could be equal
+  //    but created differently (one from JSON, one for Message, etc.),
+  //    and the hash values have to be equal even if we don't have data
+  //    yet.
+  // 2. map<> serialization order is undefined. At the time of writing
+  //    the Swift, Objective-C, and Go runtimes all tend to have random
+  //    orders, so the messages could be identical, but in binary form
+  //    they could differ.
+  public func hash(into hasher: inout Hasher) {
+    if !_typeURL.isEmpty {
+      hasher.combine(_typeURL)
+    }
+  }
+#else  // swift(>=4.2)
+  var hashValue: Int {
+    var hash: Int = i_2166136261
+    if !_typeURL.isEmpty {
+      hash = (hash &* i_16777619) ^ _typeURL.hashValue
+    }
+    return hash
+  }
+#endif  // swift(>=4.2)
+
+  func isEqualTo(other: AnyMessageStorage) -> Bool {
+    if (_typeURL != other._typeURL) {
+      return false
+    }
+
+    // Since the library does lazy Any decode, equality is a very hard problem.
+    // It things exactly match, that's pretty easy, otherwise, one ends up having
+    // to error on saying they aren't equal.
+    //
+    // The best option would be to have Message forms and compare those, as that
+    // removes issues like map<> serialization order, some other protocol buffer
+    // implementation details/bugs around serialized form order, etc.; but that
+    // would also greatly slow down equality tests.
+    //
+    // Do our best to compare what is present have...
+
+    // If both have messages, check if they are the same.
+    if case .message(let myMsg) = state, case .message(let otherMsg) = other.state, type(of: myMsg) == type(of: otherMsg) {
+      // Since the messages are known to be same type, we can claim both equal and
+      // not equal based on the equality comparison.
+      return myMsg.isEqualTo(message: otherMsg)
+    }
+
+    // If both have serialized data, and they exactly match; the messages are equal.
+    // Because there could be map in the message, the fact that the data isn't the
+    // same doesn't always mean the messages aren't equal. Likewise, the binary could
+    // have been created by a library that doesn't order the fields, or the binary was
+    // created using the appending ability in of the binary format.
+    if case .binary(let myValue) = state, case .binary(let otherValue) = other.state, myValue == otherValue {
+      return true
+    }
+
+    // If both have contentJSON, and they exactly match; the messages are equal.
+    // Because there could be map in the message (or the JSON could just be in a different
+    // order), the fact that the JSON isn't the same doesn't always mean the messages
+    // aren't equal.
+    if case .contentJSON(let myJSON, _) = state,
+       case .contentJSON(let otherJSON, _) = other.state,
+       myJSON == otherJSON {
+      return true
+    }
+
+    // Out of options. To do more compares, the states conversions would have to be
+    // done to do comparisons; and since equality can be used somewhat removed from
+    // a developer (if they put protos in a Set, use them as keys to a Dictionary, etc),
+    // the conversion cost might be to high for those uses.  Give up and say they aren't equal.
+    return false
+  }
+}
+
+// _CustomJSONCodable support for Google_Protobuf_Any
+extension AnyMessageStorage {
+  // Override the traversal-based JSON encoding
+  // This builds an Any JSON representation from one of:
+  //  * The message we were initialized with,
+  //  * The JSON fields we last deserialized, or
+  //  * The protobuf field we were deserialized from.
+  // The last case requires locating the type, deserializing
+  // into an object, then reserializing back to JSON.
+  func encodedJSONString(options: JSONEncodingOptions) throws -> String {
+    switch state {
+    case .binary(let valueData):
+      // Follow the C++ protostream_objectsource.cc's
+      // ProtoStreamObjectSource::RenderAny() special casing of an empty value.
+      guard !valueData.isEmpty else {
+        if _typeURL.isEmpty {
+          return "{}"
+        }
+        var jsonEncoder = JSONEncoder()
+        jsonEncoder.startField(name: "@type")
+        jsonEncoder.putStringValue(value: _typeURL)
+        jsonEncoder.endObject()
+        return jsonEncoder.stringResult
+      }
+      // Transcode by decoding the binary data to a message object
+      // and then recode back into JSON.
+      guard let messageType = Google_Protobuf_Any.messageType(forTypeURL: _typeURL) else {
+        // If we don't have the type available, we can't decode the
+        // binary value, so we're stuck.  (The Google spec does not
+        // provide a way to just package the binary value for someone
+        // else to decode later.)
+        throw JSONEncodingError.anyTranscodeFailure
+      }
+      let m = try messageType.init(serializedData: valueData, partial: true)
+      return try serializeAnyJSON(for: m, typeURL: _typeURL, options: options)
+
+    case .message(let msg):
+      // We should have been initialized with a typeURL, but
+      // ensure it wasn't cleared.
+      let url = !_typeURL.isEmpty ? _typeURL : buildTypeURL(forMessage: msg, typePrefix: defaultAnyTypeURLPrefix)
+      return try serializeAnyJSON(for: msg, typeURL: url, options: options)
+
+    case .contentJSON(let contentJSON, _):
+      var jsonEncoder = JSONEncoder()
+      jsonEncoder.startObject()
+      jsonEncoder.startField(name: "@type")
+      jsonEncoder.putStringValue(value: _typeURL)
+      if !contentJSON.isEmpty {
+        jsonEncoder.append(staticText: ",")
+        // NOTE: This doesn't really take `options` into account since it is
+        // just reflecting out what was taken in originally.
+        jsonEncoder.append(utf8Data: contentJSON)
+      }
+      jsonEncoder.endObject()
+      return jsonEncoder.stringResult
+    }
+  }
+
+  // TODO: If the type is well-known or has already been registered,
+  // we should consider decoding eagerly.  Eager decoding would
+  // catch certain errors earlier (good) but would probably be
+  // a performance hit if the Any contents were never accessed (bad).
+  // Of course, we can't always decode eagerly (we don't always have the
+  // message type available), so the deferred logic here is still needed.
+  func decodeJSON(from decoder: inout JSONDecoder) throws {
+    try decoder.scanner.skipRequiredObjectStart()
+    // Reset state
+    _typeURL = String()
+    state = .binary(Data())
+    if decoder.scanner.skipOptionalObjectEnd() {
+      return
+    }
+
+    var jsonEncoder = JSONEncoder()
+    while true {
+      let key = try decoder.scanner.nextQuotedString()
+      try decoder.scanner.skipRequiredColon()
+      if key == "@type" {
+        _typeURL = try decoder.scanner.nextQuotedString()
+      } else {
+        jsonEncoder.startField(name: key)
+        let keyValueJSON = try decoder.scanner.skip()
+        jsonEncoder.append(text: keyValueJSON)
+      }
+      if decoder.scanner.skipOptionalObjectEnd() {
+        // Capture the options, but set the messageDepthLimit to be what
+        // was left right now, as that is the limit when the JSON is finally
+        // parsed.
+        var updatedOptions = decoder.options
+        updatedOptions.messageDepthLimit = decoder.scanner.recursionBudget
+        state = .contentJSON(jsonEncoder.dataResult, updatedOptions)
+        return
+      }
+      try decoder.scanner.skipRequiredComma()
+    }
+  }
+}

Pods/SwiftProtobuf/Sources/SwiftProtobuf/AnyUnpackError.swift

@@ -0,0 +1,37 @@
+// Sources/SwiftProtobuf/AnyUnpackError.swift - Any Unpacking Errors
+//
+// Copyright (c) 2014 - 2017 Apple Inc. and the project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See LICENSE.txt for license information:
+// https://github.com/apple/swift-protobuf/blob/main/LICENSE.txt
+//
+// -----------------------------------------------------------------------------
+///
+/// Errors that can be throw when unpacking a Google_Protobuf_Any.
+///
+// -----------------------------------------------------------------------------
+
+/// Describes errors that can occur when unpacking an `Google_Protobuf_Any`
+/// message.
+///
+/// `Google_Protobuf_Any` messages can be decoded from protobuf binary, text
+/// format, or JSON. The contents are not parsed immediately; the raw data is
+/// held in the `Google_Protobuf_Any` message until you `unpack()` it into a
+/// message.  At this time, any error can occur that might have occurred from a
+/// regular decoding operation.  There are also other errors that can occur due
+/// to problems with the `Any` value's structure.
+public enum AnyUnpackError: Error {
+  /// The `type_url` field in the `Google_Protobuf_Any` message did not match
+  /// the message type provided to the `unpack()` method.
+  case typeMismatch
+
+  /// Well-known types being decoded from JSON must have only two fields: the
+  /// `@type` field and a `value` field containing the specialized JSON coding
+  /// of the well-known type.
+  case malformedWellKnownTypeJSON
+
+  /// The `Google_Protobuf_Any` message was malformed in some other way not
+  /// covered by the other error cases.
+  case malformedAnyField
+}

Pods/SwiftProtobuf/Sources/SwiftProtobuf/BinaryDecodingError.swift

@@ -0,0 +1,44 @@
+// Sources/SwiftProtobuf/BinaryDecodingError.swift - Protobuf binary decoding errors
+//
+// Copyright (c) 2014 - 2017 Apple Inc. and the project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See LICENSE.txt for license information:
+// https://github.com/apple/swift-protobuf/blob/main/LICENSE.txt
+//
+// -----------------------------------------------------------------------------
+///
+/// Protobuf binary format decoding errors
+///
+// -----------------------------------------------------------------------------
+
+/// Describes errors that can occur when decoding a message from binary format.
+public enum BinaryDecodingError: Error {
+  /// Extraneous data remained after decoding should have been complete.
+  case trailingGarbage
+
+  /// The decoder unexpectedly reached the end of the data before it was
+  /// expected.
+  case truncated
+
+  /// A string field was not encoded as valid UTF-8.
+  case invalidUTF8
+
+  /// The binary data was malformed in some way, such as an invalid wire format
+  /// or field tag.
+  case malformedProtobuf
+
+  /// The definition of the message or one of its nested messages has required
+  /// fields but the binary data did not include values for them. You must pass
+  /// `partial: true` during decoding if you wish to explicitly ignore missing
+  /// required fields.
+  case missingRequiredFields
+
+  /// An internal error happened while decoding.  If this is ever encountered,
+  /// please file an issue with SwiftProtobuf with as much details as possible
+  /// for what happened (proto definitions, bytes being decoded (if possible)).
+  case internalExtensionError
+
+  /// Reached the nesting limit for messages within messages while decoding.
+  case messageDepthLimit
+}

Pods/SwiftProtobuf/Sources/SwiftProtobuf/BinaryDecodingOptions.swift

@@ -0,0 +1,39 @@
+// Sources/SwiftProtobuf/BinaryDecodingOptions.swift - Binary decoding options
+//
+// Copyright (c) 2014 - 2017 Apple Inc. and the project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See LICENSE.txt for license information:
+// https://github.com/apple/swift-protobuf/blob/main/LICENSE.txt
+//
+// -----------------------------------------------------------------------------
+///
+/// Binary decoding options
+///
+// -----------------------------------------------------------------------------
+
+/// Options for binary decoding.
+public struct BinaryDecodingOptions {
+  /// The maximum nesting of message with messages.  The default is 100.
+  ///
+  /// To prevent corrupt or malicious messages from causing stack overflows,
+  /// this controls how deep messages can be nested within other messages
+  /// while parsing.
+  public var messageDepthLimit: Int = 100
+
+  /// Discard unknown fields while parsing.  The default is false, so parsering
+  /// does not discard unknown fields.
+  ///
+  /// The Protobuf binary format allows unknown fields to be still parsed
+  /// so the schema can be expanded without requiring all readers to be updated.
+  /// This works in part by haivng any unknown fields preserved so they can
+  /// be relayed on without loss. For a while the proto3 syntax definition
+  /// called for unknown fields to be dropped, but that lead to problems in
+  /// some case. The default is to follow the spec and keep them, but setting
+  /// this option to `true` allows a developer to strip them during a parse
+  /// in case they have a specific need to drop the unknown fields from the
+  /// object graph being created.
+  public var discardUnknownFields: Bool = false
+
+  public init() {}
+}

Pods/SwiftProtobuf/Sources/SwiftProtobuf/BinaryDelimited.swift

@@ -0,0 +1,250 @@
+// Sources/SwiftProtobuf/BinaryDelimited.swift - Delimited support
+//
+// Copyright (c) 2014 - 2017 Apple Inc. and the project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See LICENSE.txt for license information:
+// https://github.com/apple/swift-protobuf/blob/main/LICENSE.txt
+//
+// -----------------------------------------------------------------------------
+///
+/// Helpers to read/write message with a length prefix.
+///
+// -----------------------------------------------------------------------------
+
+#if !os(WASI)
+import Foundation
+
+/// Helper methods for reading/writing messages with a length prefix.
+public enum BinaryDelimited {
+  /// Additional errors for delimited message handing.
+  public enum Error: Swift.Error {
+    /// If a read/write to the stream fails, but the stream's `streamError` is nil,
+    /// this error will be throw instead since the stream didn't provide anything
+    /// more specific. A common cause for this can be failing to open the stream
+    /// before trying to read/write to it.
+    case unknownStreamError
+
+    /// While reading/writing to the stream, less than the expected bytes was
+    /// read/written.
+    case truncated
+  }
+
+  /// Serialize a single size-delimited message from the given stream. Delimited
+  /// format allows a single file or stream to contain multiple messages,
+  /// whereas normally writing multiple non-delimited messages to the same
+  /// stream would cause them to be merged. A delimited message is a varint
+  /// encoding the message size followed by a message of exactly that size.
+  ///
+  /// - Parameters:
+  ///   - message: The message to be written.
+  ///   - to: The `OutputStream` to write the message to.  The stream is
+  ///     is assumed to be ready to be written to.
+  ///   - partial: If `false` (the default), this method will check
+  ///     `Message.isInitialized` before encoding to verify that all required
+  ///     fields are present. If any are missing, this method throws
+  ///     `BinaryEncodingError.missingRequiredFields`.
+  /// - Throws: `BinaryEncodingError` if encoding fails, throws
+  ///           `BinaryDelimited.Error` for some writing errors, or the
+  ///           underlying `OutputStream.streamError` for a stream error.
+  public static func serialize(
+    message: Message,
+    to stream: OutputStream,
+    partial: Bool = false
+  ) throws {
+    // TODO: Revisit to avoid the extra buffering when encoding is streamed in general.
+    let serialized = try message.serializedData(partial: partial)
+    let totalSize = Varint.encodedSize(of: UInt64(serialized.count)) + serialized.count
+    var data = Data(count: totalSize)
+    data.withUnsafeMutableBytes { (body: UnsafeMutableRawBufferPointer) in
+      if let baseAddress = body.baseAddress, body.count > 0 {
+        var encoder = BinaryEncoder(forWritingInto: baseAddress)
+        encoder.putBytesValue(value: serialized)
+      }
+    }
+
+    var written: Int = 0
+    data.withUnsafeBytes { (body: UnsafeRawBufferPointer) in
+      if let baseAddress = body.baseAddress, body.count > 0 {
+        // This assumingMemoryBound is technically unsafe, but without SR-11078
+        // (https://bugs.swift.org/browse/SR-11087) we don't have another option.
+        // It should be "safe enough".
+        let pointer = baseAddress.assumingMemoryBound(to: UInt8.self)
+        written = stream.write(pointer, maxLength: totalSize)
+      }
+    }
+
+    if written != totalSize {
+      if written == -1 {
+        if let streamError = stream.streamError {
+          throw streamError
+        }
+        throw BinaryDelimited.Error.unknownStreamError
+      }
+      throw BinaryDelimited.Error.truncated
+    }
+  }
+
+  /// Reads a single size-delimited message from the given stream. Delimited
+  /// format allows a single file or stream to contain multiple messages,
+  /// whereas normally parsing consumes the entire input. A delimited message
+  /// is a varint encoding the message size followed by a message of exactly
+  /// exactly that size.
+  ///
+  /// - Parameters:
+  ///   - messageType: The type of message to read.
+  ///   - from: The `InputStream` to read the data from.  The stream is assumed
+  ///     to be ready to read from.
+  ///   - extensions: An `ExtensionMap` used to look up and decode any
+  ///     extensions in this message or messages nested within this message's
+  ///     fields.
+  ///   - partial: If `false` (the default), this method will check
+  ///     `Message.isInitialized` after decoding to verify that all required
+  ///     fields are present. If any are missing, this method throws
+  ///     `BinaryDecodingError.missingRequiredFields`.
+  ///   - options: The BinaryDecodingOptions to use.
+  /// - Returns: The message read.
+  /// - Throws: `BinaryDecodingError` if decoding fails, throws
+  ///           `BinaryDelimited.Error` for some reading errors, and the
+  ///           underlying InputStream.streamError for a stream error.
+  public static func parse<M: Message>(
+    messageType: M.Type,
+    from stream: InputStream,
+    extensions: ExtensionMap? = nil,
+    partial: Bool = false,
+    options: BinaryDecodingOptions = BinaryDecodingOptions()
+  ) throws -> M {
+    var message = M()
+    try merge(into: &message,
+              from: stream,
+              extensions: extensions,
+              partial: partial,
+              options: options)
+    return message
+  }
+
+  /// Updates the message by reading a single size-delimited message from
+  /// the given stream. Delimited format allows a single file or stream to
+  /// contain multiple messages, whereas normally parsing consumes the entire
+  /// input. A delimited message is a varint encoding the message size
+  /// followed by a message of exactly that size.
+  ///
+  /// - Note: If this method throws an error, the message may still have been
+  ///   partially mutated by the binary data that was decoded before the error
+  ///   occurred.
+  ///
+  /// - Parameters:
+  ///   - mergingTo: The message to merge the data into.
+  ///   - from: The `InputStream` to read the data from.  The stream is assumed
+  ///     to be ready to read from.
+  ///   - extensions: An `ExtensionMap` used to look up and decode any
+  ///     extensions in this message or messages nested within this message's
+  ///     fields.
+  ///   - partial: If `false` (the default), this method will check
+  ///     `Message.isInitialized` after decoding to verify that all required
+  ///     fields are present. If any are missing, this method throws
+  ///     `BinaryDecodingError.missingRequiredFields`.
+  ///   - options: The BinaryDecodingOptions to use.
+  /// - Throws: `BinaryDecodingError` if decoding fails, throws
+  ///           `BinaryDelimited.Error` for some reading errors, and the
+  ///           underlying InputStream.streamError for a stream error.
+  public static func merge<M: Message>(
+    into message: inout M,
+    from stream: InputStream,
+    extensions: ExtensionMap? = nil,
+    partial: Bool = false,
+    options: BinaryDecodingOptions = BinaryDecodingOptions()
+  ) throws {
+    let unsignedLength = try decodeVarint(stream)
+    if unsignedLength == 0 {
+      // The message was all defaults, nothing to actually read.
+      return
+    }
+    guard unsignedLength <= 0x7fffffff else {
+      // Adding a new case is a breaking change, reuse malformedProtobuf.
+      throw BinaryDecodingError.malformedProtobuf
+    }
+    let length = Int(unsignedLength)
+
+    // TODO: Consider doing a version with getBuffer:length: if the InputStream
+    // support it and thus avoiding this local copy.
+
+    // Even though the bytes are read in chunks, things can still hard fail if
+    // there isn't enough memory to append to have all the bytes at once for
+    // parsing.
+    var data = Data()
+    let kChunkSize = 16 * 1024 * 1024
+    var chunk = [UInt8](repeating: 0, count: min(length, kChunkSize))
+    var bytesNeeded = length
+    while bytesNeeded > 0 {
+      let maxLength = min(bytesNeeded, chunk.count)
+      var bytesRead: Int = 0
+      chunk.withUnsafeMutableBytes { (body: UnsafeMutableRawBufferPointer) in
+        if let baseAddress = body.baseAddress, body.count > 0 {
+          let pointer = baseAddress.assumingMemoryBound(to: UInt8.self)
+          bytesRead = stream.read(pointer, maxLength: maxLength)
+        }
+      }
+      if bytesRead == -1 {
+        if let streamError = stream.streamError {
+          throw streamError
+        }
+        throw BinaryDelimited.Error.unknownStreamError
+      }
+      if bytesRead == 0 {
+        // Hit the end of the stream
+        throw BinaryDelimited.Error.truncated
+      }
+      data.append(chunk, count: bytesRead)
+      bytesNeeded -= bytesRead
+    }
+
+    try message.merge(serializedData: data,
+                      extensions: extensions,
+                      partial: partial,
+                      options: options)
+  }
+}
+
+// TODO: This should go away when encoding/decoding are more stream based
+// as that should provide a more direct way to do this. This is basically
+// a rewrite of BinaryDecoder.decodeVarint().
+internal func decodeVarint(_ stream: InputStream) throws -> UInt64 {
+
+  // Buffer to reuse within nextByte.
+  let readBuffer = UnsafeMutablePointer<UInt8>.allocate(capacity: 1)
+  #if swift(>=4.1)
+    defer { readBuffer.deallocate() }
+  #else
+    defer { readBuffer.deallocate(capacity: 1) }
+  #endif
+
+  func nextByte() throws -> UInt8 {
+    let bytesRead = stream.read(readBuffer, maxLength: 1)
+    if bytesRead != 1 {
+      if bytesRead == -1 {
+        if let streamError = stream.streamError {
+          throw streamError
+        }
+        throw BinaryDelimited.Error.unknownStreamError
+      }
+      throw BinaryDelimited.Error.truncated
+    }
+    return readBuffer[0]
+  }
+
+  var value: UInt64 = 0
+  var shift: UInt64 = 0
+  while true {
+    let c = try nextByte()
+    value |= UInt64(c & 0x7f) << shift
+    if c & 0x80 == 0 {
+      return value
+    }
+    shift += 7
+    if shift > 63 {
+      throw BinaryDecodingError.malformedProtobuf
+    }
+  }
+}
+#endif

Pods/SwiftProtobuf/Sources/SwiftProtobuf/BinaryEncoder.swift

@@ -0,0 +1,153 @@
+// Sources/SwiftProtobuf/BinaryEncoder.swift - Binary encoding support
+//
+// Copyright (c) 2014 - 2016 Apple Inc. and the project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See LICENSE.txt for license information:
+// https://github.com/apple/swift-protobuf/blob/main/LICENSE.txt
+//
+// -----------------------------------------------------------------------------
+///
+/// Core support for protobuf binary encoding.  Note that this is built
+/// on the general traversal machinery.
+///
+// -----------------------------------------------------------------------------
+
+import Foundation
+
+/// Encoder for Binary Protocol Buffer format
+internal struct BinaryEncoder {
+    private var pointer: UnsafeMutableRawPointer
+
+    init(forWritingInto pointer: UnsafeMutableRawPointer) {
+        self.pointer = pointer
+    }
+
+    private mutating func append(_ byte: UInt8) {
+        pointer.storeBytes(of: byte, as: UInt8.self)
+        pointer = pointer.advanced(by: 1)
+    }
+
+    private mutating func append(contentsOf data: Data) {
+        data.withUnsafeBytes { dataPointer in
+            if let baseAddress = dataPointer.baseAddress, dataPointer.count > 0 {
+                pointer.copyMemory(from: baseAddress, byteCount: dataPointer.count)
+                pointer = pointer.advanced(by: dataPointer.count)
+            }
+        }
+    }
+
+    @discardableResult
+    private mutating func append(contentsOf bufferPointer: UnsafeRawBufferPointer) -> Int {
+        let count = bufferPointer.count
+        if let baseAddress = bufferPointer.baseAddress, count > 0 {
+            memcpy(pointer, baseAddress, count)
+        }
+        pointer = pointer.advanced(by: count)
+        return count
+    }
+
+    func distance(pointer: UnsafeMutableRawPointer) -> Int {
+        return pointer.distance(to: self.pointer)
+    }
+
+    mutating func appendUnknown(data: Data) {
+        append(contentsOf: data)
+    }
+
+    mutating func startField(fieldNumber: Int, wireFormat: WireFormat) {
+        startField(tag: FieldTag(fieldNumber: fieldNumber, wireFormat: wireFormat))
+    }
+
+    mutating func startField(tag: FieldTag) {
+        putVarInt(value: UInt64(tag.rawValue))
+    }
+
+    mutating func putVarInt(value: UInt64) {
+        var v = value
+        while v > 127 {
+            append(UInt8(v & 0x7f | 0x80))
+            v >>= 7
+        }
+        append(UInt8(v))
+    }
+
+    mutating func putVarInt(value: Int64) {
+        putVarInt(value: UInt64(bitPattern: value))
+    }
+
+    mutating func putVarInt(value: Int) {
+        putVarInt(value: Int64(value))
+    }
+
+    mutating func putZigZagVarInt(value: Int64) {
+        let coded = ZigZag.encoded(value)
+        putVarInt(value: coded)
+    }
+
+    mutating func putBoolValue(value: Bool) {
+        append(value ? 1 : 0)
+    }
+
+    mutating func putFixedUInt64(value: UInt64) {
+        var v = value.littleEndian
+        let n = MemoryLayout<UInt64>.size
+        memcpy(pointer, &v, n)
+        pointer = pointer.advanced(by: n)
+    }
+
+    mutating func putFixedUInt32(value: UInt32) {
+        var v = value.littleEndian
+        let n = MemoryLayout<UInt32>.size
+        memcpy(pointer, &v, n)
+        pointer = pointer.advanced(by: n)
+    }
+
+    mutating func putFloatValue(value: Float) {
+        let n = MemoryLayout<Float>.size
+        var v = value
+        var nativeBytes: UInt32 = 0
+        memcpy(&nativeBytes, &v, n)
+        var littleEndianBytes = nativeBytes.littleEndian
+        memcpy(pointer, &littleEndianBytes, n)
+        pointer = pointer.advanced(by: n)
+    }
+
+    mutating func putDoubleValue(value: Double) {
+        let n = MemoryLayout<Double>.size
+        var v = value
+        var nativeBytes: UInt64 = 0
+        memcpy(&nativeBytes, &v, n)
+        var littleEndianBytes = nativeBytes.littleEndian
+        memcpy(pointer, &littleEndianBytes, n)
+        pointer = pointer.advanced(by: n)
+    }
+
+    // Write a string field, including the leading index/tag value.
+    mutating func putStringValue(value: String) {
+        let utf8 = value.utf8
+        #if swift(>=5.0)
+            // If the String does not support an internal representation in a form
+            // of contiguous storage, body is not called and nil is returned.
+            let isAvailable = utf8.withContiguousStorageIfAvailable { (body: UnsafeBufferPointer<UInt8>) -> Int in
+                putVarInt(value: body.count)
+                return append(contentsOf: UnsafeRawBufferPointer(body))
+            }
+        #else
+            let isAvailable: Int? = nil
+        #endif
+            if isAvailable == nil {
+                let count = utf8.count
+                putVarInt(value: count)
+                for b in utf8 {
+                    pointer.storeBytes(of: b, as: UInt8.self)
+                    pointer = pointer.advanced(by: 1)
+                }
+            }
+    }
+
+    mutating func putBytesValue(value: Data) {
+        putVarInt(value: value.count)
+        append(contentsOf: value)
+    }
+}