@@ -5,16 +5,19 @@
55{-# LANGUAGE FlexibleInstances #-}
66{-# LANGUAGE GADTs #-}
77{-# LANGUAGE MultiParamTypeClasses #-}
8−{-# LANGUAGE NoImplicitPrelude #-}
8+{-# LANGUAGE NamedFieldPuns #-}
99{-# LANGUAGE OverloadedStrings #-}
10−{-# LANGUAGE PolyKinds #-}
1110{-# LANGUAGE RecordWildCards #-}
1211{-# LANGUAGE ScopedTypeVariables #-}
1312{-# LANGUAGE TypeOperators #-}
14−{-# LANGUAGE TupleSections #-}
13+{-# LANGUAGE TypeSynonymInstances #-}
1514{-# LANGUAGE UndecidableInstances #-}
1615{-# LANGUAGE ViewPatterns #-}
1716
17+#if __GLASGOW_HASKELL__ >= 706
18+{-# LANGUAGE PolyKinds #-}
19+#endif
20+
1821#include "incoherent-compat.h"
1922#include "overlapping-compat.h"
2023
@@ -42,9 +45,6 @@ module Data.Aeson.Types.FromJSON
4245 , coerceFromJSONKeyFunction
4346 , mapFromJSONKeyFunction
4447
45− , GFromJSONKey()
46− , genericFromJSONKey
47−
4848 -- * List functions
4949 , listParser
5050
@@ -60,14 +60,12 @@ module Data.Aeson.Types.FromJSON
6060 , fromJSON
6161 , ifromJSON
6262 , typeMismatch
63− , unexpected
6463 , parseField
6564 , parseFieldMaybe
6665 , parseFieldMaybe'
6766 , explicitParseField
6867 , explicitParseFieldMaybe
6968 , explicitParseFieldMaybe'
70− , parseIndexedJSON
7169 -- ** Operators
7270 , (.:)
7371 , (.:?)
@@ -78,16 +76,18 @@ module Data.Aeson.Types.FromJSON
7876 , parseOptionalFieldWith
7977 ) where
8078
79+import Prelude ()
8180import Prelude.Compat
8281
83−import Control.Applicative ((<|>), Const(..), liftA2)
84−import Control.Monad (zipWithM)
82+import Control.Applicative ((<|>), Const(..))
83+import Control.Monad ((<=<), zipWithM)
8584import Data.Aeson.Internal.Functions (mapKey)
8685import Data.Aeson.Parser.Internal (eitherDecodeWith, jsonEOF)
8786import Data.Aeson.Types.Generic
8887import Data.Aeson.Types.Internal
88+import Data.Attoparsec.Number (Number(..))
8989import Data.Bits (unsafeShiftR)
90−import Data.Fixed (Fixed, HasResolution (resolution), Nano)
90+import Data.Fixed (Fixed, HasResolution)
9191import Data.Functor.Compose (Compose(..))
9292import Data.Functor.Identity (Identity(..))
9393import Data.Functor.Product (Product(..))
@@ -99,18 +99,15 @@ import Data.Maybe (fromMaybe)
9999import Data.Semigroup ((<>))
100100import Data.Proxy (Proxy(..))
101101import Data.Ratio ((%), Ratio)
102−import Data.Scientific (Scientific, base10Exponent)
102+import Data.Scientific (Scientific)
103103import Data.Tagged (Tagged(..))
104104import Data.Text (Text, pack, unpack)
105105import Data.Time (Day, DiffTime, LocalTime, NominalDiffTime, TimeOfDay, UTCTime, ZonedTime)
106−import Data.Time.Calendar.Compat (CalendarDiffDays (..), DayOfWeek (..))
107−import Data.Time.LocalTime.Compat (CalendarDiffTime (..))
108−import Data.Time.Clock.System.Compat (SystemTime (..))
109−import Data.Time.Format.Compat (parseTimeM, defaultTimeLocale)
106+import Data.Time.Format (parseTime)
107+import Data.Time.Locale.Compat (defaultTimeLocale)
110108import Data.Traversable as Tr (sequence)
111109import Data.Vector (Vector)
112110import Data.Version (Version, parseVersion)
113−import Data.Void (Void)
114111import Data.Word (Word16, Word32, Word64, Word8)
115112import Foreign.Storable (Storable)
116113import Foreign.C.Types (CTime (..))
@@ -118,9 +115,9 @@ import GHC.Generics
118115import Numeric.Natural (Natural)
119116import Text.ParserCombinators.ReadP (readP_to_S)
120117import Unsafe.Coerce (unsafeCoerce)
118+import qualified Data.Aeson.Compat as Compat
121119import qualified Data.Aeson.Parser.Time as Time
122120import qualified Data.Attoparsec.ByteString.Char8 as A (endOfInput, parseOnly, scientific)
123−import qualified Data.ByteString.Lazy as L
124121import qualified Data.DList as DList
125122import qualified Data.HashMap.Strict as H
126123import qualified Data.HashSet as HashSet
@@ -143,20 +140,18 @@ import qualified Data.Vector.Primitive as VP
143140import qualified Data.Vector.Storable as VS
144141import qualified Data.Vector.Unboxed as VU
145142
146−import qualified GHC.Exts as Exts
147−import qualified Data.Primitive.Array as PM
148−import qualified Data.Primitive.SmallArray as PM
149−import qualified Data.Primitive.Types as PM
150−
151−#if MIN_VERSION_primitive(0,6,4)
152−#if !MIN_VERSION_primitive(0,7,0)
153−import qualified Data.Primitive.UnliftedArray as PM
143+#ifndef HAS_COERCIBLE
144+#define HAS_COERCIBLE (__GLASGOW_HASKELL__ >= 707)
154145#endif
155−import qualified Data.Primitive.PrimArray as PM
156−#endif
157−
158146
147+#if HAS_COERCIBLE
159148import Data.Coerce (Coercible, coerce)
149+coerce' :: Coercible a b => a -> b
150+coerce' = coerce
151+#else
152+coerce' :: a -> b
153+coerce' = unsafeCoerce
154+#endif
160155
161156parseIndexedJSON :: (Value -> Parser a) -> Int -> Value -> Parser a
162157parseIndexedJSON p idx value = p value <?> Index idx
@@ -165,7 +160,7 @@ parseIndexedJSON p idx value = p value <?> Index idx
165160parseIndexedJSONPair :: (Value -> Parser a) -> (Value -> Parser b) -> Int -> Value -> Parser (a, b)
166161parseIndexedJSONPair keyParser valParser idx value = p value <?> Index idx
167162 where
168− p = withArray "(k, v)" $ \ab ->
163+ p = withArray "(k,v)" $ \ab ->
169164 let n = V.length ab
170165 in if n == 2
171166 then (,) <$> parseJSONElemAtIndex keyParser 0 ab
@@ -177,34 +172,43 @@ parseIndexedJSONPair keyParser valParser idx value = p value <?> Index idx
177172parseJSONElemAtIndex :: (Value -> Parser a) -> Int -> V.Vector Value -> Parser a
178173parseJSONElemAtIndex p idx ary = p (V.unsafeIndex ary idx) <?> Index idx
179174
175+scientificToNumber :: Scientific -> Number
176+scientificToNumber s
177+ | e < 0 = D $ Scientific.toRealFloat s
178+ | otherwise = I $ c * 10 ^ e
179+ where
180+ e = Scientific.base10Exponent s
181+ c = Scientific.coefficient s
182+{-# INLINE scientificToNumber #-}
183+
180184parseRealFloat :: RealFloat a => String -> Value -> Parser a
181−parseRealFloat _ (Number s) = pure $ Scientific.toRealFloat s
182−parseRealFloat _ Null = pure (0/0)
183−parseRealFloat name v = prependContext name (unexpected v)
185+parseRealFloat _ (Number s) = pure $ Scientific.toRealFloat s
186+parseRealFloat _ Null = pure (0/0)
187+parseRealFloat expected v = typeMismatch expected v
184188{-# INLINE parseRealFloat #-}
185189
186−parseIntegralFromScientific :: forall a. Integral a => Scientific -> Parser a
187−parseIntegralFromScientific s =
190+parseIntegralFromScientific :: forall a. Integral a => String -> Scientific -> Parser a
191+parseIntegralFromScientific expected s =
188192 case Scientific.floatingOrInteger s :: Either Double a of
189193 Right x -> pure x
190− Left _ -> fail $ "unexpected floating number " ++ show s
194+ Left _ -> fail $ "expected " ++ expected ++ ", encountered floating number " ++ show s
191195{-# INLINE parseIntegralFromScientific #-}
192196
193197parseIntegral :: Integral a => String -> Value -> Parser a
194−parseIntegral name =
195− prependContext name . withBoundedScientific' parseIntegralFromScientific
198+parseIntegral expected =
199+ withScientific expected $ parseIntegralFromScientific expected
196200{-# INLINE parseIntegral #-}
197201
198−parseBoundedIntegralFromScientific :: (Bounded a, Integral a) => Scientific -> Parser a
199−parseBoundedIntegralFromScientific s = maybe
200− (fail $ "value is either floating or will cause over or underflow " ++ show s)
202+parseBoundedIntegralFromScientific :: (Bounded a, Integral a) => String -> Scientific -> Parser a
203+parseBoundedIntegralFromScientific expected s = maybe
204+ (fail $ expected ++ " is either floating or will cause over or underflow: " ++ show s)
201205 pure
202206 (Scientific.toBoundedInteger s)
203207{-# INLINE parseBoundedIntegralFromScientific #-}
204208
205209parseBoundedIntegral :: (Bounded a, Integral a) => String -> Value -> Parser a
206−parseBoundedIntegral name =
207− prependContext name . withScientific' parseBoundedIntegralFromScientific
210+parseBoundedIntegral expected =
211+ withScientific expected $ parseBoundedIntegralFromScientific expected
208212{-# INLINE parseBoundedIntegral #-}
209213
210214parseScientificText :: Text -> Parser Scientific
@@ -214,20 +218,13 @@ parseScientificText
214218 . T.encodeUtf8
215219
216220parseIntegralText :: Integral a => String -> Text -> Parser a
217−parseIntegralText name t =
218− prependContext name $
219− parseScientificText t
220− >>= rejectLargeExponent
221− >>= parseIntegralFromScientific
222− where
223− rejectLargeExponent :: Scientific -> Parser Scientific
224− rejectLargeExponent s = withBoundedScientific' pure (Number s)
221+parseIntegralText expected t =
222+ parseScientificText t >>= parseIntegralFromScientific expected
225223{-# INLINE parseIntegralText #-}
226224
227225parseBoundedIntegralText :: (Bounded a, Integral a) => String -> Text -> Parser a
228−parseBoundedIntegralText name t =
229− prependContext name $
230− parseScientificText t >>= parseBoundedIntegralFromScientific
226+parseBoundedIntegralText expected t =
227+ parseScientificText t >>= parseBoundedIntegralFromScientific expected
231228
232229parseOptionalFieldWith :: (Value -> Parser (Maybe a))
233230 -> Object -> Text -> Parser (Maybe a)
@@ -287,21 +284,14 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
287284--
288285-- The basic ways to signal a failed conversion are as follows:
289286--
290−-- * 'fail' yields a custom error message: it is the recommended way of
291−-- reporting a failure;
292−--
293−-- * 'Control.Applicative.empty' (or 'Control.Monad.mzero') is uninformative:
294−-- use it when the error is meant to be caught by some @('<|>')@;
287+-- * 'empty' and 'mzero' work, but are terse and uninformative;
295288--
296−-- * 'typeMismatch' can be used to report a failure when the encountered value
297−-- is not of the expected JSON type; 'unexpected' is an appropriate alternative
298−-- when more than one type may be expected, or to keep the expected type
299−-- implicit.
289+-- * 'fail' yields a custom error message;
300290--
301−-- 'prependFailure' (or 'modifyFailure') add more information to a parser's
302−-- error messages.
291+-- * 'typeMismatch' produces an informative message for cases when the
292+-- value encountered is not of the expected type.
303293--
304−-- An example type and instance using 'typeMismatch' and 'prependFailure':
294+-- An example type and instance using 'typeMismatch':
305295--
306296-- @
307297-- \-- Allow ourselves to write 'Text' literals.
@@ -315,15 +305,13 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
315305-- '<*>' v '.:' \"y\"
316306--
317307-- \-- We do not expect a non-'Object' value here.
318−-- \-- We could use 'Control.Applicative.empty' to fail, but 'typeMismatch'
308+-- \-- We could use 'mzero' to fail, but 'typeMismatch'
319309-- \-- gives a much more informative error message.
320−-- 'parseJSON' invalid =
321−-- 'prependFailure' "parsing Coord failed, "
322−-- ('typeMismatch' \"Object\" invalid)
310+-- 'parseJSON' invalid = 'typeMismatch' \"Coord\" invalid
323311-- @
324312--
325313-- For this common case of only being concerned with a single
326−-- type of JSON value, the functions 'withObject', 'withScientific', etc.
314+-- type of JSON value, the functions 'withObject', 'withNumber', etc.
327315-- are provided. Their use is to be preferred when possible, since
328316-- they are more terse. Using 'withObject', we can rewrite the above instance
329317-- (assuming the same language extension and data type) as:
@@ -362,7 +350,7 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
362350-- @
363351--
364352-- The default implementation will be equivalent to
365−-- @parseJSON = 'genericParseJSON' 'defaultOptions'@; if you need different
353+-- @parseJSON = 'genericParseJSON' 'defaultOptions'@; If you need different
366354-- options, you can customize the generic decoding by defining:
367355--
368356-- @
@@ -380,11 +368,13 @@ class FromJSON a where
380368 parseJSON = genericParseJSON defaultOptions
381369
382370 parseJSONList :: Value -> Parser [a]
383− parseJSONList = withArray "[]" $ \a ->
384− zipWithM (parseIndexedJSON parseJSON) [0..]
371+ parseJSONList (Array a)
372+ = zipWithM (parseIndexedJSON parseJSON) [0..]
385373 . V.toList
386374 $ a
387375
376+ parseJSONList v = typeMismatch "[a]" v
377+
388378-------------------------------------------------------------------------------
389379-- Classes and types for map keys
390380-------------------------------------------------------------------------------
@@ -396,16 +386,6 @@ class FromJSON a where
396386-- > newtype SomeId = SomeId { getSomeId :: Text }
397387-- > deriving (Eq,Ord,Hashable,FromJSONKey)
398388--
399−-- If you have a sum of nullary constructors, you may use the generic
400−-- implementation:
401−--
402−-- @
403−-- data Color = Red | Green | Blue
404−-- deriving Generic
405−--
406−-- instance 'FromJSONKey' Color where
407−-- 'fromJSONKey' = 'genericFromJSONKey' 'defaultJSONKeyOptions'
408−-- @
409389class FromJSONKey a where
410390 -- | Strategy for parsing the key of a map-like container.
411391 fromJSONKey :: FromJSONKeyFunction a
@@ -428,7 +408,11 @@ class FromJSONKey a where
428408-- At the moment this type is intentionally not exported. 'FromJSONKeyFunction'
429409-- can be inspected, but cannot be constructed.
430410data CoerceText a where
411+#if HAS_COERCIBLE
431412 CoerceText :: Coercible Text a => CoerceText a
413+#else
414+ CoerceText :: CoerceText a
415+#endif
432416
433417-- | This type is related to 'ToJSONKeyFunction'. If 'FromJSONKeyValue' is used in the
434418-- 'FromJSONKey' instance, then 'ToJSONKeyValue' should be used in the 'ToJSONKey'
@@ -448,7 +432,7 @@ data FromJSONKeyFunction a
448432
449433-- | Only law abiding up to interpretation
450434instance Functor FromJSONKeyFunction where
451− fmap h (FromJSONKeyCoerce CoerceText) = FromJSONKeyText (h . coerce)
435+ fmap h (FromJSONKeyCoerce CoerceText) = FromJSONKeyText (h . coerce')
452436 fmap h (FromJSONKeyText f) = FromJSONKeyText (h . f)
453437 fmap h (FromJSONKeyTextParser f) = FromJSONKeyTextParser (fmap h . f)
454438 fmap h (FromJSONKeyValue f) = FromJSONKeyValue (fmap h . f)
@@ -462,7 +446,9 @@ instance Functor FromJSONKeyFunction where
462446--
463447-- On pre GHC 7.8 this is unconstrainted function.
464448fromJSONKeyCoerce ::
449+#if HAS_COERCIBLE
465450 Coercible Text a =>
451+#endif
466452 FromJSONKeyFunction a
467453fromJSONKeyCoerce = FromJSONKeyCoerce CoerceText
468454
@@ -470,91 +456,60 @@ fromJSONKeyCoerce = FromJSONKeyCoerce CoerceText
470456--
471457-- See note on 'fromJSONKeyCoerce'.
472458coerceFromJSONKeyFunction ::
459+#if HAS_COERCIBLE
473460 Coercible a b =>
461+#endif
474462 FromJSONKeyFunction a -> FromJSONKeyFunction b
463+#if HAS_COERCIBLE
475464coerceFromJSONKeyFunction = coerce
465+#else
466+coerceFromJSONKeyFunction (FromJSONKeyCoerce CoerceText) = FromJSONKeyCoerce CoerceText
467+coerceFromJSONKeyFunction (FromJSONKeyText f) = FromJSONKeyText (coerce' . f)
468+coerceFromJSONKeyFunction (FromJSONKeyTextParser f) = FromJSONKeyTextParser (fmap coerce' . f)
469+coerceFromJSONKeyFunction (FromJSONKeyValue f) = FromJSONKeyValue (fmap coerce' . f)
470+#endif
476471
477472{-# RULES
478473 "FromJSONKeyCoerce: fmap id" forall (x :: FromJSONKeyFunction a).
479474 fmap id x = x
480475 #-}
476+#if HAS_COERCIBLE
481477{-# RULES
482478 "FromJSONKeyCoerce: fmap coerce" forall x .
483479 fmap coerce x = coerceFromJSONKeyFunction x
484480 #-}
481+#endif
485482
486483-- | Same as 'fmap'. Provided for the consistency with 'ToJSONKeyFunction'.
487484mapFromJSONKeyFunction :: (a -> b) -> FromJSONKeyFunction a -> FromJSONKeyFunction b
488485mapFromJSONKeyFunction = fmap
489486
490−-- | 'fromJSONKey' for 'Generic' types.
491−-- These types must be sums of nullary constructors, whose names will be used
492−-- as keys for JSON objects.
493−--
494−-- See also 'genericToJSONKey'.
495−--
496−-- === __Example__
497−--
498−-- @
499−-- data Color = Red | Green | Blue
500−-- deriving 'Generic'
501−--
502−-- instance 'FromJSONKey' Color where
503−-- 'fromJSONKey' = 'genericFromJSONKey' 'defaultJSONKeyOptions'
504−-- @
505−genericFromJSONKey :: forall a. (Generic a, GFromJSONKey (Rep a))
506− => JSONKeyOptions
507− -> FromJSONKeyFunction a
508−genericFromJSONKey opts = FromJSONKeyTextParser $ \t ->
509− case parseSumFromString (keyModifier opts) t of
510− Nothing -> fail $
511− "invalid key " ++ show t ++ ", expected one of " ++ show cnames
512− Just k -> pure (to k)
513− where
514− cnames = unTagged2 (constructorTags (keyModifier opts) :: Tagged2 (Rep a) [String])
515−
516−class (ConstructorNames f, SumFromString f) => GFromJSONKey f where
517−instance (ConstructorNames f, SumFromString f) => GFromJSONKey f where
518−
519487-------------------------------------------------------------------------------
520488-- Functions needed for documentation
521489-------------------------------------------------------------------------------
522490
523491-- | Fail parsing due to a type mismatch, with a descriptive message.
524492--
525−-- The following wrappers should generally be prefered:
526−-- 'withObject', 'withArray', 'withText', 'withBool'.
527−--
528−-- ==== Error message example
493+-- Example usage:
529494--
530−-- > typeMismatch "Object" (String "oops")
531−-- > -- Error: "expected Object, but encountered String"
532−typeMismatch :: String -- ^ The name of the JSON type being parsed
533− -- (@\"Object\"@, @\"Array\"@, @\"String\"@, @\"Number\"@,
534− -- @\"Boolean\"@, or @\"Null\"@).
495+-- @
496+-- instance FromJSON Coord where
497+-- parseJSON ('Object' v) = {- type matches, life is good -}
498+-- parseJSON wat = 'typeMismatch' \"Coord\" wat
499+-- @
500+typeMismatch :: String -- ^ The name of the type you are trying to parse.
535501 -> Value -- ^ The actual value encountered.
536502 -> Parser a
537503typeMismatch expected actual =
538− fail $ "expected " ++ expected ++ ", but encountered " ++ typeOf actual
539−
540−-- | Fail parsing due to a type mismatch, when the expected types are implicit.
541−--
542−-- ==== Error message example
543−--
544−-- > unexpected (String "oops")
545−-- > -- Error: "unexpected String"
546−unexpected :: Value -> Parser a
547−unexpected actual = fail $ "unexpected " ++ typeOf actual
548−
549−-- | JSON type of a value, name of the head constructor.
550−typeOf :: Value -> String
551−typeOf v = case v of
552− Object _ -> "Object"
553− Array _ -> "Array"
554− String _ -> "String"
555− Number _ -> "Number"
556− Bool _ -> "Boolean"
557− Null -> "Null"
504+ fail $ "expected " ++ expected ++ ", encountered " ++ name
505+ where
506+ name = case actual of
507+ Object _ -> "Object"
508+ Array _ -> "Array"
509+ String _ -> "String"
510+ Number _ -> "Number"
511+ Bool _ -> "Boolean"
512+ Null -> "Null"
558513
559514-------------------------------------------------------------------------------
560515-- Lifings of FromJSON and ToJSON to unary and binary type constructors
@@ -635,8 +590,9 @@ class FromJSON2 f where
635590 -> (Value -> Parser b)
636591 -> (Value -> Parser [b])
637592 -> Value -> Parser [f a b]
638− liftParseJSONList2 fa ga fb gb = withArray "[]" $ \vals ->
639− fmap V.toList (V.mapM (liftParseJSON2 fa ga fb gb) vals)
593+ liftParseJSONList2 fa ga fb gb v = case v of
594+ Array vals -> fmap V.toList (V.mapM (liftParseJSON2 fa ga fb gb) vals)
595+ _ -> typeMismatch "[a]" v
640596
641597-- | Lift the standard 'parseJSON' function through the type constructor.
642598parseJSON2 :: (FromJSON2 f, FromJSON a, FromJSON b) => Value -> Parser (f a b)
@@ -650,7 +606,7 @@ parseJSON2 = liftParseJSON2 parseJSON parseJSONList parseJSON parseJSONList
650606-- | Helper function to use with 'liftParseJSON'. See 'Data.Aeson.ToJSON.listEncoding'.
651607listParser :: (Value -> Parser a) -> Value -> Parser [a]
652608listParser f (Array xs) = fmap V.toList (V.mapM f xs)
653−listParser _ v = typeMismatch "Array" v
609+listParser _ v = typeMismatch "[a]" v
654610{-# INLINE listParser #-}
655611
656612-------------------------------------------------------------------------------
@@ -668,137 +624,50 @@ instance (FromJSON a) => FromJSON [a] where
668624-- Functions
669625-------------------------------------------------------------------------------
670626
671−-- | Add context to a failure message, indicating the name of the structure
672−-- being parsed.
673−--
674−-- > prependContext "MyType" (fail "[error message]")
675−-- > -- Error: "parsing MyType failed, [error message]"
676−prependContext :: String -> Parser a -> Parser a
677−prependContext name = prependFailure ("parsing " ++ name ++ " failed, ")
678−
679−-- | @'withObject' name f value@ applies @f@ to the 'Object' when @value@
680−-- is an 'Data.Aeson.Object' and fails otherwise.
681−--
682−-- ==== Error message example
683−--
684−-- > withObject "MyType" f (String "oops")
685−-- > -- Error: "parsing MyType failed, expected Object, but encountered String"
627+-- | @'withObject' expected f value@ applies @f@ to the 'Object' when @value@
628+-- is an 'Object' and fails using @'typeMismatch' expected@ otherwise.
686629withObject :: String -> (Object -> Parser a) -> Value -> Parser a
687−withObject _ f (Object obj) = f obj
688−withObject name _ v = prependContext name (typeMismatch "Object" v)
630+withObject _ f (Object obj) = f obj
631+withObject expected _ v = typeMismatch expected v
689632{-# INLINE withObject #-}
690633
691−-- | @'withText' name f value@ applies @f@ to the 'Text' when @value@ is a
692−-- 'Data.Aeson.String' and fails otherwise.
693−--
694−-- ==== Error message example
695−--
696−-- > withText "MyType" f Null
697−-- > -- Error: "parsing MyType failed, expected String, but encountered Null"
634+-- | @'withText' expected f value@ applies @f@ to the 'Text' when @value@ is a
635+-- 'String' and fails using @'typeMismatch' expected@ otherwise.
698636withText :: String -> (Text -> Parser a) -> Value -> Parser a
699−withText _ f (String txt) = f txt
700−withText name _ v = prependContext name (typeMismatch "String" v)
637+withText _ f (String txt) = f txt
638+withText expected _ v = typeMismatch expected v
701639{-# INLINE withText #-}
702640
703641-- | @'withArray' expected f value@ applies @f@ to the 'Array' when @value@ is
704−-- an 'Data.Aeson.Array' and fails otherwise.
705−--
706−-- ==== Error message example
707−--
708−-- > withArray "MyType" f (String "oops")
709−-- > -- Error: "parsing MyType failed, expected Array, but encountered String"
642+-- an 'Array' and fails using @'typeMismatch' expected@ otherwise.
710643withArray :: String -> (Array -> Parser a) -> Value -> Parser a
711−withArray _ f (Array arr) = f arr
712−withArray name _ v = prependContext name (typeMismatch "Array" v)
644+withArray _ f (Array arr) = f arr
645+withArray expected _ v = typeMismatch expected v
713646{-# INLINE withArray #-}
714647
715−-- | @'withScientific' name f value@ applies @f@ to the 'Scientific' number
716−-- when @value@ is a 'Data.Aeson.Number' and fails using 'typeMismatch'
648+-- | @'withScientific' expected f value@ applies @f@ to the 'Scientific' number
649+-- when @value@ is a 'Number' and fails using @'typeMismatch' expected@
717650-- otherwise.
718−--
719−-- /Warning/: If you are converting from a scientific to an unbounded
720−-- type such as 'Integer' you may want to add a restriction on the
721−-- size of the exponent (see 'withBoundedScientific') to prevent
722−-- malicious input from filling up the memory of the target system.
723−--
724−-- ==== Error message example
725−--
726−-- > withScientific "MyType" f (String "oops")
727−-- > -- Error: "parsing MyType failed, expected Number, but encountered String"
728651withScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a
729−withScientific _ f (Number scientific) = f scientific
730−withScientific name _ v = prependContext name (typeMismatch "Number" v)
652+withScientific _ f (Number scientific) = f scientific
653+withScientific expected _ v = typeMismatch expected v
731654{-# INLINE withScientific #-}
732655
733−-- | A variant of 'withScientific' which doesn't use 'prependContext', so that
734−-- such context can be added separately in a way that also applies when the
735−-- continuation @f :: Scientific -> Parser a@ fails.
736−--
737−-- /Warning/: If you are converting from a scientific to an unbounded
738−-- type such as 'Integer' you may want to add a restriction on the
739−-- size of the exponent (see 'withBoundedScientific') to prevent
740−-- malicious input from filling up the memory of the target system.
741−--
742−-- ==== Error message examples
743−--
744−-- > withScientific' f (String "oops")
745−-- > -- Error: "unexpected String"
746−-- >
747−-- > prependContext "MyType" (withScientific' f (String "oops"))
748−-- > -- Error: "parsing MyType failed, unexpected String"
749−withScientific' :: (Scientific -> Parser a) -> Value -> Parser a
750−withScientific' f v = case v of
751− Number n -> f n
752− _ -> typeMismatch "Number" v
753−{-# INLINE withScientific' #-}
754−
755−-- | @'withBoundedScientific' name f value@ applies @f@ to the 'Scientific' number
756−-- when @value@ is a 'Number' with exponent less than or equal to 1024.
757−withBoundedScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a
758−withBoundedScientific name f v = withBoundedScientific_ (prependContext name) f v
759−{-# INLINE withBoundedScientific #-}
760−
761−-- | A variant of 'withBoundedScientific' which doesn't use 'prependContext',
762−-- so that such context can be added separately in a way that also applies
763−-- when the continuation @f :: Scientific -> Parser a@ fails.
764−withBoundedScientific' :: (Scientific -> Parser a) -> Value -> Parser a
765−withBoundedScientific' f v = withBoundedScientific_ id f v
766−{-# INLINE withBoundedScientific' #-}
767−
768−-- | A variant of 'withBoundedScientific_' parameterized by a function to apply
769−-- to the 'Parser' in case of failure.
770−withBoundedScientific_ :: (Parser a -> Parser a) -> (Scientific -> Parser a) -> Value -> Parser a
771−withBoundedScientific_ whenFail f (Number scientific) =
772− if exp10 > 1024
773− then whenFail (fail msg)
774− else f scientific
775− where
776− exp10 = base10Exponent scientific
777− msg = "found a number with exponent " ++ show exp10 ++ ", but it must not be greater than 1024"
778−withBoundedScientific_ whenFail _ v =
779− whenFail (typeMismatch "Number" v)
780−{-# INLINE withBoundedScientific_ #-}
781−
782656-- | @'withBool' expected f value@ applies @f@ to the 'Bool' when @value@ is a
783−-- 'Boolean' and fails otherwise.
784−--
785−-- ==== Error message example
786−--
787−-- > withBool "MyType" f (String "oops")
788−-- > -- Error: "parsing MyType failed, expected Boolean, but encountered String"
657+-- 'Bool' and fails using @'typeMismatch' expected@ otherwise.
789658withBool :: String -> (Bool -> Parser a) -> Value -> Parser a
790−withBool _ f (Bool arr) = f arr
791−withBool name _ v = prependContext name (typeMismatch "Boolean" v)
659+withBool _ f (Bool arr) = f arr
660+withBool expected _ v = typeMismatch expected v
792661{-# INLINE withBool #-}
793662
794663-- | Decode a nested JSON-encoded string.
795664withEmbeddedJSON :: String -> (Value -> Parser a) -> Value -> Parser a
796665withEmbeddedJSON _ innerParser (String txt) =
797− either fail innerParser $ eitherDecode (L.fromStrict $ T.encodeUtf8 txt)
666+ either fail innerParser $ eitherDecode (Compat.fromStrict $ T.encodeUtf8 txt)
798667 where
799668 eitherDecode = eitherFormatError . eitherDecodeWith jsonEOF ifromJSON
800669 eitherFormatError = either (Left . uncurry formatError) Right
801−withEmbeddedJSON name _ v = prependContext name (typeMismatch "String" v)
670+withEmbeddedJSON name _ v = typeMismatch name v
802671{-# INLINE withEmbeddedJSON #-}
803672
804673-- | Convert a value from JSON, failing if the types do not match.
@@ -863,7 +732,7 @@ parseFieldMaybe' = (.:!)
863732-- E.g. @'explicitParseField' 'parseJSON1' :: ('FromJSON1' f, 'FromJSON' a) -> 'Object' -> 'Text' -> 'Parser' (f a)@
864733explicitParseField :: (Value -> Parser a) -> Object -> Text -> Parser a
865734explicitParseField p obj key = case H.lookup key obj of
866− Nothing -> fail $ "key " ++ show key ++ " not found"
735+ Nothing -> fail $ "key " ++ show key ++ " not present"
867736 Just v -> p v <?> Key key
868737{-# INLINE explicitParseField #-}
869738
@@ -903,47 +772,11 @@ pmval .!= val = fromMaybe val <$> pmval
903772-- Generic parseJSON
904773-------------------------------------------------------------------------------
905774
906−instance GFromJSON arity V1 where
907− -- Whereof we cannot format, thereof we cannot parse:
908− gParseJSON _ _ _ = fail "Attempted to parse empty type"
909−
910−
911775instance OVERLAPPABLE_ (GFromJSON arity a) => GFromJSON arity (M1 i c a) where
912776 -- Meta-information, which is not handled elsewhere, is just added to the
913777 -- parsed value:
914778 gParseJSON opts fargs = fmap M1 . gParseJSON opts fargs
915779
916−-- Information for error messages
917−
918−type TypeName = String
919−type ConName = String
920−
921−-- | Add the name of the type being parsed to a parser's error messages.
922−contextType :: TypeName -> Parser a -> Parser a
923−contextType = prependContext
924−
925−-- | Add the tagKey that will be looked up while building an ADT
926−-- | Produce the error equivalent to
927−-- | Left "Error in $: parsing T failed, expected an object with keys "tag" and
928−-- | "contents", where "tag" i-- |s associated to one of ["Foo", "Bar"],
929−-- | The parser returned error was: could not find key "tag"
930−contextTag :: Text -> [String] -> Parser a -> Parser a
931−contextTag tagKey cnames = prependFailure
932− ("expected Object with key \"" ++ unpack tagKey ++ "\"" ++
933− " containing one of " ++ show cnames ++ ", ")
934−
935−-- | Add the name of the constructor being parsed to a parser's error messages.
936−contextCons :: ConName -> TypeName -> Parser a -> Parser a
937−contextCons cname tname = prependContext (showCons cname tname)
938−
939−-- | Render a constructor as @\"MyType(MyConstructor)\"@.
940−showCons :: ConName -> TypeName -> String
941−showCons cname tname = tname ++ "(" ++ cname ++ ")"
942−
943−--------------------------------------------------------------------------------
944−
945−-- Parsing single fields
946−
947780instance (FromJSON a) => GFromJSON arity (K1 i a) where
948781 -- Constant values are decoded using their FromJSON instance:
949782 gParseJSON _opts _ = fmap K1 . parseJSON
@@ -958,499 +791,342 @@ instance (FromJSON1 f) => GFromJSON One (Rec1 f) where
958791 -- FromJSON1 instance:
959792 gParseJSON _opts (From1Args pj pjl) = fmap Rec1 . liftParseJSON pj pjl
960793
961−instance (FromJSON1 f, GFromJSON One g) => GFromJSON One (f :.: g) where
962− -- If an occurrence of the last type parameter is nested inside two
963− -- composed types, it is decoded by using the outermost type's FromJSON1
964− -- instance to generically decode the innermost type:
965− gParseJSON opts fargs =
966− let gpj = gParseJSON opts fargs in
967− fmap Comp1 . liftParseJSON gpj (listParser gpj)
968−
969−--------------------------------------------------------------------------------
970−
971−instance (GFromJSON' arity a, Datatype d) => GFromJSON arity (D1 d a) where
972− -- Meta-information, which is not handled elsewhere, is just added to the
973− -- parsed value:
974− gParseJSON opts fargs = fmap M1 . gParseJSON' (tname :* opts :* fargs)
975− where
976− tname = moduleName proxy ++ "." ++ datatypeName proxy
977− proxy = undefined :: M1 _i d _f _p
978−
979−-- | 'GFromJSON', after unwrapping the 'D1' constructor, now carrying the data
980−-- type's name.
981−class GFromJSON' arity f where
982− gParseJSON' :: TypeName :* Options :* FromArgs arity a
983− -> Value
984− -> Parser (f a)
794+instance GFromJSON arity U1 where
795+ -- Empty constructors are expected to be encoded as an empty array:
796+ gParseJSON _opts _ v
797+ | isEmptyArray v = pure U1
798+ | otherwise = typeMismatch "unit constructor (U1)" v
985799
986−-- | Single constructor.
987800instance ( ConsFromJSON arity a
988801 , AllNullary (C1 c a) allNullary
989802 , ParseSum arity (C1 c a) allNullary
990− , Constructor c
991− ) => GFromJSON' arity (C1 c a) where
803+ ) => GFromJSON arity (D1 d (C1 c a)) where
992804 -- The option 'tagSingleConstructors' determines whether to wrap
993805 -- a single-constructor type.
994− gParseJSON' p@(_ :* opts :* _)
806+ gParseJSON opts fargs
995807 | tagSingleConstructors opts
996− = (unTagged :: Tagged allNullary (Parser (C1 c a p)) -> Parser (C1 c a p))
997− . parseSum p
998− | otherwise = fmap M1 . consParseJSON (cname :* p)
999− where
1000− cname = conName (undefined :: M1 _i c _f _p)
1001−
1002−-- | Multiple constructors.
1003−instance ( AllNullary (a :+: b) allNullary
1004− , ParseSum arity (a :+: b) allNullary
1005− ) => GFromJSON' arity (a :+: b) where
808+ = fmap M1
809+ . (unTagged :: Tagged allNullary (Parser (C1 c a p)) -> Parser (C1 c a p))
810+ . parseSum opts fargs
811+ | otherwise = fmap M1 . fmap M1 . consParseJSON opts fargs
812+
813+instance (ConsFromJSON arity a) => GFromJSON arity (C1 c a) where
814+ -- Constructors need to be decoded differently depending on whether they're
815+ -- a record or not. This distinction is made by consParseJSON:
816+ gParseJSON opts fargs = fmap M1 . consParseJSON opts fargs
817+
818+instance ( FromProduct arity a, FromProduct arity b
819+ , ProductSize a, ProductSize b
820+ ) => GFromJSON arity (a :*: b) where
821+ -- Products are expected to be encoded to an array. Here we check whether we
822+ -- got an array of the same size as the product, then parse each of the
823+ -- product's elements using parseProduct:
824+ gParseJSON opts fargs = withArray "product (:*:)" $ \arr ->
825+ let lenArray = V.length arr
826+ lenProduct = (unTagged2 :: Tagged2 (a :*: b) Int -> Int)
827+ productSize in
828+ if lenArray == lenProduct
829+ then parseProduct opts fargs arr 0 lenProduct
830+ else fail $ "When expecting a product of " ++ show lenProduct ++
831+ " values, encountered an Array of " ++ show lenArray ++
832+ " elements instead"
833+
834+instance ( AllNullary (a :+: b) allNullary
835+ , ParseSum arity (a :+: b) allNullary
836+ ) => GFromJSON arity (a :+: b) where
1006837 -- If all constructors of a sum datatype are nullary and the
1007838 -- 'allNullaryToStringTag' option is set they are expected to be
1008839 -- encoded as strings. This distinction is made by 'parseSum':
1009− gParseJSON' p =
1010− (unTagged :: Tagged allNullary (Parser ((a :+: b) _d)) ->
1011− Parser ((a :+: b) _d))
1012− . parseSum p
840+ gParseJSON opts fargs =
841+ (unTagged :: Tagged allNullary (Parser ((a :+: b) d)) ->
842+ Parser ((a :+: b) d))
843+ . parseSum opts fargs
844+
845+instance (FromJSON1 f, GFromJSON One g) => GFromJSON One (f :.: g) where
846+ -- If an occurrence of the last type parameter is nested inside two
847+ -- composed types, it is decoded by using the outermost type's FromJSON1
848+ -- instance to generically decode the innermost type:
849+ gParseJSON opts fargs =
850+ let gpj = gParseJSON opts fargs in
851+ fmap Comp1 . liftParseJSON gpj (listParser gpj)
1013852
1014853--------------------------------------------------------------------------------
1015854
1016855class ParseSum arity f allNullary where
1017− parseSum :: TypeName :* Options :* FromArgs arity a
1018− -> Value
1019− -> Tagged allNullary (Parser (f a))
856+ parseSum :: Options -> FromArgs arity a
857+ -> Value -> Tagged allNullary (Parser (f a))
1020858
1021−instance ( ConstructorNames f
1022− , SumFromString f
859+instance ( SumFromString f
1023860 , FromPair arity f
1024861 , FromTaggedObject arity f
1025862 , FromUntaggedValue arity f
1026863 ) => ParseSum arity f True where
1027− parseSum p@(tname :* opts :* _)
1028− | allNullaryToStringTag opts = Tagged . parseAllNullarySum tname opts
1029− | otherwise = Tagged . parseNonAllNullarySum p
864+ parseSum opts fargs
865+ | allNullaryToStringTag opts = Tagged . parseAllNullarySum opts
866+ | otherwise = Tagged . parseNonAllNullarySum opts fargs
1030867
1031−instance ( ConstructorNames f
1032− , FromPair arity f
868+instance ( FromPair arity f
1033869 , FromTaggedObject arity f
1034870 , FromUntaggedValue arity f
1035871 ) => ParseSum arity f False where
1036− parseSum p = Tagged . parseNonAllNullarySum p
872+ parseSum opts fargs = Tagged . parseNonAllNullarySum opts fargs
1037873
1038874--------------------------------------------------------------------------------
1039875
1040−parseAllNullarySum :: (SumFromString f, ConstructorNames f)
1041− => TypeName -> Options -> Value -> Parser (f a)
1042−parseAllNullarySum tname opts =
1043− withText tname $ \tag ->
1044− maybe (badTag tag) return $
1045− parseSumFromString modifier tag
1046− where
1047− badTag tag = failWithCTags tname modifier $ \cnames ->
1048− "expected one of the tags " ++ show cnames ++
1049− ", but found tag " ++ show tag
1050− modifier = constructorTagModifier opts
1051−
1052−-- | Fail with an informative error message about a mismatched tag.
1053−-- The error message is parameterized by the list of expected tags,
1054−-- to be inferred from the result type of the parser.
1055−failWithCTags
1056− :: forall f a t. ConstructorNames f
1057− => TypeName -> (String -> t) -> ([t] -> String) -> Parser (f a)
1058−failWithCTags tname modifier f =
1059− contextType tname . fail $ f cnames
1060− where
1061− cnames = unTagged2 (constructorTags modifier :: Tagged2 f [t])
876+parseAllNullarySum :: SumFromString f => Options -> Value -> Parser (f a)
877+parseAllNullarySum opts = withText "Text" $ \key ->
878+ maybe (notFound key) return $
879+ parseSumFromString opts key
1062880
1063881class SumFromString f where
1064− parseSumFromString :: (String -> String) -> Text -> Maybe (f a)
882+ parseSumFromString :: Options -> Text -> Maybe (f a)
1065883
1066884instance (SumFromString a, SumFromString b) => SumFromString (a :+: b) where
1067885 parseSumFromString opts key = (L1 <$> parseSumFromString opts key) <|>
1068886 (R1 <$> parseSumFromString opts key)
1069887
1070888instance (Constructor c) => SumFromString (C1 c U1) where
1071− parseSumFromString modifier key
1072− | key == name = Just $ M1 U1
1073− | otherwise = Nothing
1074− where
1075− name = pack $ modifier $ conName (undefined :: M1 _i c _f _p)
1076−
1077−-- For genericFromJSONKey
1078−instance SumFromString a => SumFromString (D1 d a) where
1079− parseSumFromString modifier key = M1 <$> parseSumFromString modifier key
1080−
1081−-- | List of all constructor tags.
1082−constructorTags :: ConstructorNames a => (String -> t) -> Tagged2 a [t]
1083−constructorTags modifier =
1084− fmap DList.toList (constructorNames' modifier)
1085−
1086−-- | List of all constructor names of an ADT, after a given conversion
1087−-- function. (Better inlining.)
1088−class ConstructorNames a where
1089− constructorNames' :: (String -> t) -> Tagged2 a (DList.DList t)
1090−
1091−instance (ConstructorNames a, ConstructorNames b) => ConstructorNames (a :+: b) where
1092− constructorNames' = liftA2 append constructorNames' constructorNames'
1093− where
1094− append
1095− :: Tagged2 a (DList.DList t)
1096− -> Tagged2 b (DList.DList t)
1097− -> Tagged2 (a :+: b) (DList.DList t)
1098− append (Tagged2 xs) (Tagged2 ys) = Tagged2 (DList.append xs ys)
1099−
1100−instance Constructor c => ConstructorNames (C1 c a) where
1101− constructorNames' f = Tagged2 (pure (f cname))
1102− where
1103− cname = conName (undefined :: M1 _i c _f _p)
1104−
1105−-- For genericFromJSONKey
1106−instance ConstructorNames a => ConstructorNames (D1 d a) where
1107− constructorNames' = retag . constructorNames'
1108− where
1109− retag :: Tagged2 a u -> Tagged2 (D1 d a) u
1110− retag (Tagged2 x) = Tagged2 x
889+ parseSumFromString opts key | key == name = Just $ M1 U1
890+ | otherwise = Nothing
891+ where
892+ name = pack $ constructorTagModifier opts $
893+ conName (undefined :: t c U1 p)
1111894
1112895--------------------------------------------------------------------------------
1113−parseNonAllNullarySum :: forall f c arity.
1114− ( FromPair arity f
896+
897+parseNonAllNullarySum :: ( FromPair arity f
1115898 , FromTaggedObject arity f
1116899 , FromUntaggedValue arity f
1117− , ConstructorNames f
1118− ) => TypeName :* Options :* FromArgs arity c
900+ ) => Options -> FromArgs arity c
1119901 -> Value -> Parser (f c)
1120−parseNonAllNullarySum p@(tname :* opts :* _) =
902+parseNonAllNullarySum opts fargs =
1121903 case sumEncoding opts of
1122904 TaggedObject{..} ->
1123− withObject tname $ \obj -> do
1124− tag <- contextType tname . contextTag tagKey cnames_ $ obj .: tagKey
1125− fromMaybe (badTag tag <?> Key tagKey) $
1126− parseFromTaggedObject (tag :* contentsFieldName :* p) obj
1127− where
1128− tagKey = pack tagFieldName
1129− badTag tag = failWith_ $ \cnames ->
1130− "expected tag field to be one of " ++ show cnames ++
1131− ", but found tag " ++ show tag
1132− cnames_ = unTagged2 (constructorTags (constructorTagModifier opts) :: Tagged2 f [String])
905+ withObject "Object" $ \obj -> do
906+ tag <- obj .: pack tagFieldName
907+ fromMaybe (notFound tag) $
908+ parseFromTaggedObject opts fargs contentsFieldName obj tag
1133909
1134910 ObjectWithSingleField ->
1135− withObject tname $ \obj -> case H.toList obj of
1136− [(tag, v)] -> maybe (badTag tag) (<?> Key tag) $
1137− parsePair (tag :* p) v
1138− _ -> contextType tname . fail $
1139− "expected an Object with a single pair, but found " ++
1140− show (H.size obj) ++ " pairs"
1141− where
1142− badTag tag = failWith_ $ \cnames ->
1143− "expected an Object with a single pair where the tag is one of " ++
1144− show cnames ++ ", but found tag " ++ show tag
911+ withObject "Object" $ \obj ->
912+ case H.toList obj of
913+ [pair@(tag, _)] -> fromMaybe (notFound tag) $
914+ parsePair opts fargs pair
915+ _ -> fail "Object doesn't have a single field"
1145916
1146917 TwoElemArray ->
1147− withArray tname $ \arr -> case V.length arr of
1148− 2 | String tag <- V.unsafeIndex arr 0 ->
1149− maybe (badTag tag <?> Index 0) (<?> Index 1) $
1150− parsePair (tag :* p) (V.unsafeIndex arr 1)
1151− | otherwise ->
1152− contextType tname $
1153− fail "tag element is not a String" <?> Index 0
1154− len -> contextType tname . fail $
1155− "expected a 2-element Array, but encountered an Array of length " ++
1156− show len
1157− where
1158− badTag tag = failWith_ $ \cnames ->
1159− "expected tag of the 2-element Array to be one of " ++
1160− show cnames ++ ", but found tag " ++ show tag
918+ withArray "Array" $ \arr ->
919+ if V.length arr == 2
920+ then case V.unsafeIndex arr 0 of
921+ String tag -> fromMaybe (notFound tag) $
922+ parsePair opts fargs (tag, V.unsafeIndex arr 1)
923+ _ -> fail "First element is not a String"
924+ else fail "Array doesn't have 2 elements"
1161925
1162− UntaggedValue -> parseUntaggedValue p
1163− where
1164− failWith_ = failWithCTags tname (constructorTagModifier opts)
926+ UntaggedValue -> parseUntaggedValue opts fargs
1165927
1166928--------------------------------------------------------------------------------
1167929
1168930class FromTaggedObject arity f where
1169− -- The first two components of the parameter tuple are: the constructor tag
1170− -- to match against, and the contents field name.
1171− parseFromTaggedObject
1172− :: Text :* String :* TypeName :* Options :* FromArgs arity a
1173− -> Object
1174− -> Maybe (Parser (f a))
931+ parseFromTaggedObject :: Options -> FromArgs arity a
932+ -> String -> Object
933+ -> Text -> Maybe (Parser (f a))
1175934
1176935instance ( FromTaggedObject arity a, FromTaggedObject arity b) =>
1177936 FromTaggedObject arity (a :+: b) where
1178− parseFromTaggedObject p obj =
1179− (fmap L1 <$> parseFromTaggedObject p obj) <|>
1180− (fmap R1 <$> parseFromTaggedObject p obj)
937+ parseFromTaggedObject opts fargs contentsFieldName obj tag =
938+ (fmap L1 <$> parseFromTaggedObject opts fargs contentsFieldName obj tag) <|>
939+ (fmap R1 <$> parseFromTaggedObject opts fargs contentsFieldName obj tag)
1181940
1182−instance ( IsRecord f isRecord
1183− , FromTaggedObject' arity f isRecord
941+instance ( FromTaggedObject' arity f
1184942 , Constructor c
1185943 ) => FromTaggedObject arity (C1 c f) where
1186− parseFromTaggedObject (tag :* contentsFieldName :* p@(_ :* opts :* _))
1187− | tag == tag'
1188− = Just . fmap M1 .
1189− (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a)) .
1190− parseFromTaggedObject' (contentsFieldName :* cname :* p)
1191− | otherwise = const Nothing
1192− where
1193− tag' = pack $ constructorTagModifier opts cname
1194− cname = conName (undefined :: M1 _i c _f _p)
944+ parseFromTaggedObject opts fargs contentsFieldName obj tag
945+ | tag == name = Just $ M1 <$> parseFromTaggedObject'
946+ opts fargs contentsFieldName obj
947+ | otherwise = Nothing
948+ where
949+ name = pack $ constructorTagModifier opts $
950+ conName (undefined :: t c f p)
1195951
1196952--------------------------------------------------------------------------------
1197953
1198−class FromTaggedObject' arity f isRecord where
1199− -- The first component of the parameter tuple is the contents field name.
1200− parseFromTaggedObject'
1201− :: String :* ConName :* TypeName :* Options :* FromArgs arity a
1202− -> Object -> Tagged isRecord (Parser (f a))
1203−
1204−instance (RecordFromJSON arity f, FieldNames f) => FromTaggedObject' arity f True where
1205− -- Records are unpacked in the tagged object
1206− parseFromTaggedObject' (_ :* p) = Tagged . recordParseJSON (True :* p)
1207−
1208−instance (ConsFromJSON arity f) => FromTaggedObject' arity f False where
1209− -- Nonnullary nonrecords are encoded in the contents field
1210− parseFromTaggedObject' p obj = Tagged $ do
1211− contents <- contextCons cname tname (obj .: key)
1212− consParseJSON p' contents <?> Key key
1213− where
1214− key = pack contentsFieldName
1215− contentsFieldName :* p'@(cname :* tname :* _) = p
954+class FromTaggedObject' arity f where
955+ parseFromTaggedObject' :: Options -> FromArgs arity a -> String
956+ -> Object -> Parser (f a)
957+
958+class FromTaggedObject'' arity f isRecord where
959+ parseFromTaggedObject'' :: Options -> FromArgs arity a -> String
960+ -> Object -> Tagged isRecord (Parser (f a))
961+
962+instance ( IsRecord f isRecord
963+ , FromTaggedObject'' arity f isRecord
964+ ) => FromTaggedObject' arity f where
965+ parseFromTaggedObject' opts fargs contentsFieldName =
966+ (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a)) .
967+ parseFromTaggedObject'' opts fargs contentsFieldName
968+
969+instance (FromRecord arity f) => FromTaggedObject'' arity f True where
970+ parseFromTaggedObject'' opts fargs _ =
971+ Tagged . parseRecord opts fargs
972+
973+instance (GFromJSON arity f) => FromTaggedObject'' arity f False where
974+ parseFromTaggedObject'' opts fargs contentsFieldName = Tagged .
975+ (gParseJSON opts fargs <=< (.: pack contentsFieldName))
1216976
1217−instance OVERLAPPING_ FromTaggedObject' arity U1 False where
1218− -- Nullary constructors don't need a contents field
1219− parseFromTaggedObject' _ _ = Tagged (pure U1)
977+instance OVERLAPPING_ FromTaggedObject'' arity U1 False where
978+ parseFromTaggedObject'' _ _ _ _ = Tagged (pure U1)
1220979
1221980--------------------------------------------------------------------------------
1222981
1223−-- | Constructors need to be decoded differently depending on whether they're
1224−-- a record or not. This distinction is made by 'ConsParseJSON'.
1225982class ConsFromJSON arity f where
1226− consParseJSON
1227− :: ConName :* TypeName :* Options :* FromArgs arity a
1228− -> Value -> Parser (f a)
983+ consParseJSON :: Options -> FromArgs arity a
984+ -> Value -> Parser (f a)
1229985
1230986class ConsFromJSON' arity f isRecord where
1231− consParseJSON'
1232− :: ConName :* TypeName :* Options :* FromArgs arity a
1233− -> Value -> Tagged isRecord (Parser (f a))
987+ consParseJSON' :: Options -> FromArgs arity a
988+ -> Value -> Tagged isRecord (Parser (f a))
1234989
1235990instance ( IsRecord f isRecord
1236991 , ConsFromJSON' arity f isRecord
1237992 ) => ConsFromJSON arity f where
1238− consParseJSON p =
993+ consParseJSON opts fargs =
1239994 (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a))
1240− . consParseJSON' p
995+ . consParseJSON' opts fargs
1241996
1242997instance OVERLAPPING_
1243− ( GFromJSON arity a, RecordFromJSON arity (S1 s a)
998+ ( GFromJSON arity a, FromRecord arity (S1 s a)
1244999 ) => ConsFromJSON' arity (S1 s a) True where
1245− consParseJSON' p@(cname :* tname :* opts :* fargs)
1246− | unwrapUnaryRecords opts = Tagged . fmap M1 . gParseJSON opts fargs
1247− | otherwise = Tagged . withObject (showCons cname tname) (recordParseJSON (False :* p))
1000+ consParseJSON' opts fargs
1001+ | unwrapUnaryRecords opts = Tagged . gParseJSON opts fargs
1002+ | otherwise = Tagged . withObject "unary record" (parseRecord opts fargs)
12481003
1249−instance RecordFromJSON arity f => ConsFromJSON' arity f True where
1250− consParseJSON' p@(cname :* tname :* _) =
1251− Tagged . withObject (showCons cname tname) (recordParseJSON (False :* p))
1004+instance FromRecord arity f => ConsFromJSON' arity f True where
1005+ consParseJSON' opts fargs =
1006+ Tagged . withObject "record (:*:)" (parseRecord opts fargs)
12521007
1253−instance OVERLAPPING_
1254− ConsFromJSON' arity U1 False where
1255− -- Empty constructors are expected to be encoded as an empty array:
1256− consParseJSON' (cname :* tname :* _) v =
1257− Tagged . contextCons cname tname $ case v of
1258− Array a | V.null a -> pure U1
1259− | otherwise -> fail_ a
1260− _ -> typeMismatch "Array" v
1261− where
1262− fail_ a = fail $
1263− "expected an empty Array, but encountered an Array of length " ++
1264− show (V.length a)
1265−
1266−instance OVERLAPPING_
1267− GFromJSON arity f => ConsFromJSON' arity (S1 s f) False where
1268− consParseJSON' (_ :* _ :* opts :* fargs) =
1269− Tagged . fmap M1 . gParseJSON opts fargs
1270−
1271−instance (ProductFromJSON arity f, ProductSize f
1272− ) => ConsFromJSON' arity f False where
1273− consParseJSON' p = Tagged . productParseJSON0 p
1008+instance GFromJSON arity f => ConsFromJSON' arity f False where
1009+ consParseJSON' opts fargs = Tagged . gParseJSON opts fargs
12741010
12751011--------------------------------------------------------------------------------
12761012
1277−class FieldNames f where
1278− fieldNames :: f a -> [Text] -> [Text]
1279−
1280−instance (FieldNames a, FieldNames b) => FieldNames (a :*: b) where
1281− fieldNames _ =
1282− fieldNames (undefined :: a x) .
1283− fieldNames (undefined :: b y)
1284−
1285−instance (Selector s) => FieldNames (S1 s f) where
1286− fieldNames _ = (pack (selName (undefined :: M1 _i s _f _p)) :)
1013+class FromRecord arity f where
1014+ parseRecord :: Options -> FromArgs arity a
1015+ -> Object -> Parser (f a)
12871016
1288−class RecordFromJSON arity f where
1289− recordParseJSON
1290− :: Bool :* ConName :* TypeName :* Options :* FromArgs arity a
1291− -> Object -> Parser (f a)
1292−
1293−instance ( FieldNames f
1294− , RecordFromJSON' arity f
1295− ) => RecordFromJSON arity f where
1296− recordParseJSON (fromTaggedSum :* p@(cname :* tname :* opts :* _)) =
1297− \obj -> checkUnknown obj >> recordParseJSON' p obj
1298− where
1299− knownFields :: H.HashMap Text ()
1300− knownFields = H.fromList $ map (,()) $
1301− fieldNames (undefined :: f a)
1302− [pack (tagFieldName (sumEncoding opts)) | fromTaggedSum]
1303− checkUnknown =
1304− if not (rejectUnknownFields opts)
1305− then \_ -> return ()
1306− else \obj -> case H.keys (H.difference obj knownFields) of
1307− [] -> return ()
1308− unknownFields -> contextCons cname tname $
1309− fail ("unknown fields: " ++ show unknownFields)
1310−
1311−class RecordFromJSON' arity f where
1312− recordParseJSON'
1313− :: ConName :* TypeName :* Options :* FromArgs arity a
1314− -> Object -> Parser (f a)
1315−
1316−instance ( RecordFromJSON' arity a
1317− , RecordFromJSON' arity b
1318− ) => RecordFromJSON' arity (a :*: b) where
1319− recordParseJSON' p obj =
1320− (:*:) <$> recordParseJSON' p obj
1321− <*> recordParseJSON' p obj
1017+instance ( FromRecord arity a
1018+ , FromRecord arity b
1019+ ) => FromRecord arity (a :*: b) where
1020+ parseRecord opts fargs obj =
1021+ (:*:) <$> parseRecord opts fargs obj
1022+ <*> parseRecord opts fargs obj
13221023
13231024instance OVERLAPPABLE_ (Selector s, GFromJSON arity a) =>
1324− RecordFromJSON' arity (S1 s a) where
1325− recordParseJSON' (cname :* tname :* opts :* fargs) obj = do
1326− fv <- contextCons cname tname (obj .: label)
1327− M1 <$> gParseJSON opts fargs fv <?> Key label
1328− where
1329− label = pack $ fieldLabelModifier opts sname
1330− sname = selName (undefined :: M1 _i s _f _p)
1025+ FromRecord arity (S1 s a) where
1026+ parseRecord opts fargs =
1027+ (<?> Key label) . gParseJSON opts fargs <=< (.: label)
1028+ where
1029+ label = pack . fieldLabelModifier opts $ selName (undefined :: t s a p)
13311030
13321031instance INCOHERENT_ (Selector s, FromJSON a) =>
1333− RecordFromJSON' arity (S1 s (K1 i (Maybe a))) where
1334− recordParseJSON' (_ :* _ :* opts :* _) obj = M1 . K1 <$> obj .:? pack label
1335− where
1336− label = fieldLabelModifier opts sname
1337− sname = selName (undefined :: M1 _i s _f _p)
1032+ FromRecord arity (S1 s (K1 i (Maybe a))) where
1033+ parseRecord opts _ obj = M1 . K1 <$> obj .:? pack label
1034+ where
1035+ label = fieldLabelModifier opts $
1036+ selName (undefined :: t s (K1 i (Maybe a)) p)
13381037
13391038-- Parse an Option like a Maybe.
13401039instance INCOHERENT_ (Selector s, FromJSON a) =>
1341− RecordFromJSON' arity (S1 s (K1 i (Semigroup.Option a))) where
1342− recordParseJSON' p obj = wrap <$> recordParseJSON' p obj
1040+ FromRecord arity (S1 s (K1 i (Semigroup.Option a))) where
1041+ parseRecord opts fargs obj = wrap <$> parseRecord opts fargs obj
13431042 where
13441043 wrap :: S1 s (K1 i (Maybe a)) p -> S1 s (K1 i (Semigroup.Option a)) p
13451044 wrap (M1 (K1 a)) = M1 (K1 (Semigroup.Option a))
13461045
13471046--------------------------------------------------------------------------------
13481047
1349−productParseJSON0
1350− :: forall f arity a. (ProductFromJSON arity f, ProductSize f)
1351− => ConName :* TypeName :* Options :* FromArgs arity a
1352− -> Value -> Parser (f a)
1353− -- Products are expected to be encoded to an array. Here we check whether we
1354− -- got an array of the same size as the product, then parse each of the
1355− -- product's elements using productParseJSON:
1356−productParseJSON0 p@(cname :* tname :* _ :* _) =
1357− withArray (showCons cname tname) $ \arr ->
1358− let lenArray = V.length arr
1359− lenProduct = (unTagged2 :: Tagged2 f Int -> Int)
1360− productSize in
1361− if lenArray == lenProduct
1362− then productParseJSON p arr 0 lenProduct
1363− else contextCons cname tname $
1364− fail $ "expected an Array of length " ++ show lenProduct ++
1365− ", but encountered an Array of length " ++ show lenArray
1366−
1367−--
1368−
1369−class ProductFromJSON arity f where
1370− productParseJSON :: ConName :* TypeName :* Options :* FromArgs arity a
1048+class FromProduct arity f where
1049+ parseProduct :: Options -> FromArgs arity a
13711050 -> Array -> Int -> Int
13721051 -> Parser (f a)
13731052
1374−instance ( ProductFromJSON arity a
1375− , ProductFromJSON arity b
1376− ) => ProductFromJSON arity (a :*: b) where
1377− productParseJSON p arr ix len =
1378− (:*:) <$> productParseJSON p arr ix lenL
1379− <*> productParseJSON p arr ixR lenR
1053+instance ( FromProduct arity a
1054+ , FromProduct arity b
1055+ ) => FromProduct arity (a :*: b) where
1056+ parseProduct opts fargs arr ix len =
1057+ (:*:) <$> parseProduct opts fargs arr ix lenL
1058+ <*> parseProduct opts fargs arr ixR lenR
13801059 where
13811060 lenL = len `unsafeShiftR` 1
13821061 ixR = ix + lenL
13831062 lenR = len - lenL
13841063
1385−instance (GFromJSON arity a) => ProductFromJSON arity (S1 s a) where
1386− productParseJSON (_ :* _ :* opts :* fargs) arr ix _ =
1387− M1 <$> gParseJSON opts fargs (V.unsafeIndex arr ix) <?> Index ix
1064+instance (GFromJSON arity a) => FromProduct arity (S1 s a) where
1065+ parseProduct opts fargs arr ix _ =
1066+ gParseJSON opts fargs $ V.unsafeIndex arr ix
13881067
13891068--------------------------------------------------------------------------------
13901069
13911070class FromPair arity f where
1392− -- The first component of the parameter tuple is the tag to match.
1393− parsePair :: Text :* TypeName :* Options :* FromArgs arity a
1394− -> Value
1395− -> Maybe (Parser (f a))
1071+ parsePair :: Options -> FromArgs arity a
1072+ -> Pair -> Maybe (Parser (f a))
13961073
13971074instance ( FromPair arity a
13981075 , FromPair arity b
13991076 ) => FromPair arity (a :+: b) where
1400− parsePair p pair =
1401− (fmap L1 <$> parsePair p pair) <|>
1402− (fmap R1 <$> parsePair p pair)
1077+ parsePair opts fargs pair = (fmap L1 <$> parsePair opts fargs pair) <|>
1078+ (fmap R1 <$> parsePair opts fargs pair)
14031079
14041080instance ( Constructor c
1081+ , GFromJSON arity a
14051082 , ConsFromJSON arity a
14061083 ) => FromPair arity (C1 c a) where
1407− parsePair (tag :* p@(_ :* opts :* _)) v
1408− | tag == tag' = Just $ M1 <$> consParseJSON (cname :* p) v
1084+ parsePair opts fargs (tag, value)
1085+ | tag == tag' = Just $ gParseJSON opts fargs value
14091086 | otherwise = Nothing
1410− where
1411− tag' = pack $ constructorTagModifier opts cname
1412− cname = conName (undefined :: M1 _i c _a _p)
1087+ where
1088+ tag' = pack $ constructorTagModifier opts $
1089+ conName (undefined :: t c a p)
14131090
14141091--------------------------------------------------------------------------------
14151092
14161093class FromUntaggedValue arity f where
1417− parseUntaggedValue :: TypeName :* Options :* FromArgs arity a
1418− -> Value
1419− -> Parser (f a)
1094+ parseUntaggedValue :: Options -> FromArgs arity a
1095+ -> Value -> Parser (f a)
14201096
14211097instance
14221098 ( FromUntaggedValue arity a
14231099 , FromUntaggedValue arity b
14241100 ) => FromUntaggedValue arity (a :+: b)
14251101 where
1426− parseUntaggedValue p value =
1427− L1 <$> parseUntaggedValue p value <|>
1428− R1 <$> parseUntaggedValue p value
1102+ parseUntaggedValue opts fargs value =
1103+ L1 <$> parseUntaggedValue opts fargs value <|>
1104+ R1 <$> parseUntaggedValue opts fargs value
14291105
14301106instance OVERLAPPABLE_
1431− ( ConsFromJSON arity a
1432− , Constructor c
1107+ ( GFromJSON arity a
1108+ , ConsFromJSON arity a
14331109 ) => FromUntaggedValue arity (C1 c a)
14341110 where
1435− parseUntaggedValue p = fmap M1 . consParseJSON (cname :* p)
1436− where
1437− cname = conName (undefined :: M1 _i c _f _p)
1111+ parseUntaggedValue = gParseJSON
14381112
14391113instance OVERLAPPING_
14401114 ( Constructor c )
14411115 => FromUntaggedValue arity (C1 c U1)
14421116 where
1443− parseUntaggedValue (tname :* opts :* _) v =
1444− contextCons cname tname $ case v of
1445− String tag
1446− | tag == tag' -> pure $ M1 U1
1447− | otherwise -> fail_ tag
1448− _ -> typeMismatch "String" v
1449− where
1450− tag' = pack $ constructorTagModifier opts cname
1451− cname = conName (undefined :: M1 _i c _f _p)
1452− fail_ tag = fail $
1453− "expected tag " ++ show tag' ++ ", but found tag " ++ show tag
1117+ parseUntaggedValue opts _ (String s)
1118+ | s == pack (constructorTagModifier opts (conName (undefined :: t c U1 p))) =
1119+ pure $ M1 U1
1120+ | otherwise =
1121+ fail $ "Invalid tag: " ++ unpack s
1122+ parseUntaggedValue _ _ v = typeMismatch (conName (undefined :: t c U1 p)) v
1123+
1124+
1125+--------------------------------------------------------------------------------
1126+
1127+notFound :: Text -> Parser a
1128+notFound key = fail $ "The key \"" ++ unpack key ++ "\" was not found"
1129+{-# INLINE notFound #-}
14541130
14551131-------------------------------------------------------------------------------
14561132-- Instances
@@ -1508,20 +1184,17 @@ instance (FromJSON a, FromJSON b) => FromJSON (Either a b) where
15081184 parseJSON = parseJSON2
15091185 {-# INLINE parseJSON #-}
15101186
1511−instance FromJSON Void where
1512− parseJSON _ = fail "Cannot parse Void"
1513− {-# INLINE parseJSON #-}
1187+
15141188
15151189instance FromJSON Bool where
1516− parseJSON (Bool b) = pure b
1517− parseJSON v = typeMismatch "Bool" v
1190+ parseJSON = withBool "Bool" pure
15181191 {-# INLINE parseJSON #-}
15191192
15201193instance FromJSONKey Bool where
15211194 fromJSONKey = FromJSONKeyTextParser $ \t -> case t of
15221195 "true" -> pure True
15231196 "false" -> pure False
1524− _ -> fail $ "cannot parse key " ++ show t ++ " into Bool"
1197+ _ -> fail $ "Cannot parse key into Bool: " ++ T.unpack t
15251198
15261199instance FromJSON Ordering where
15271200 parseJSON = withText "Ordering" $ \s ->
@@ -1529,30 +1202,25 @@ instance FromJSON Ordering where
15291202 "LT" -> return LT
15301203 "EQ" -> return EQ
15311204 "GT" -> return GT
1532− _ -> fail $ "parsing Ordering failed, unexpected " ++ show s ++
1533− " (expected \"LT\", \"EQ\", or \"GT\")"
1205+ _ -> fail "Parsing Ordering value failed: expected \"LT\", \"EQ\", or \"GT\""
15341206
15351207instance FromJSON () where
15361208 parseJSON = withArray "()" $ \v ->
15371209 if V.null v
15381210 then pure ()
1539− else prependContext "()" $ fail "expected an empty array"
1211+ else fail "Expected an empty array"
15401212 {-# INLINE parseJSON #-}
15411213
15421214instance FromJSON Char where
1543− parseJSON = withText "Char" parseChar
1215+ parseJSON = withText "Char" $ \t ->
1216+ if T.compareLength t 1 == EQ
1217+ then pure $ T.head t
1218+ else fail "Expected a string of length 1"
15441219 {-# INLINE parseJSON #-}
15451220
1546− parseJSONList (String s) = pure (T.unpack s)
1547− parseJSONList v = typeMismatch "String" v
1221+ parseJSONList = withText "String" $ pure . T.unpack
15481222 {-# INLINE parseJSONList #-}
15491223
1550−parseChar :: Text -> Parser Char
1551−parseChar t =
1552− if T.compareLength t 1 == EQ
1553− then pure $ T.head t
1554− else prependContext "Char" $ fail "expected a string of length 1"
1555−
15561224instance FromJSON Double where
15571225 parseJSON = parseRealFloat "Double"
15581226 {-# INLINE parseJSON #-}
@@ -1564,6 +1232,12 @@ instance FromJSONKey Double where
15641232 "-Infinity" -> pure (negate 1/0)
15651233 _ -> Scientific.toRealFloat <$> parseScientificText t
15661234
1235+instance FromJSON Number where
1236+ parseJSON (Number s) = pure $ scientificToNumber s
1237+ parseJSON Null = pure (D (0/0))
1238+ parseJSON v = typeMismatch "Number" v
1239+ {-# INLINE parseJSON #-}
1240+
15671241instance FromJSON Float where
15681242 parseJSON = parseRealFloat "Float"
15691243 {-# INLINE parseJSON #-}
@@ -1576,30 +1250,20 @@ instance FromJSONKey Float where
15761250 _ -> Scientific.toRealFloat <$> parseScientificText t
15771251
15781252instance (FromJSON a, Integral a) => FromJSON (Ratio a) where
1579− parseJSON (Number x)
1580− | exp10 <= 1024
1581− , exp10 >= -1024 = return $! realToFrac x
1582− | otherwise = prependContext "Ratio" $ fail msg
1583− where
1584− exp10 = base10Exponent x
1585− msg = "found a number with exponent " ++ show exp10
1586− ++ ", but it must not be greater than 1024 or less than -1024"
1587− parseJSON o = objParser o
1588− where
1589− objParser = withObject "Rational" $ \obj -> do
1590− numerator <- obj .: "numerator"
1591− denominator <- obj .: "denominator"
1592− if denominator == 0
1593− then fail "Ratio denominator was 0"
1594− else pure $ numerator % denominator
1595− {-# INLINE parseJSON #-}
1596−
1597−-- | This instance includes a bounds check to prevent maliciously
1598−-- large inputs to fill up the memory of the target system. You can
1599−-- newtype 'Scientific' and provide your own instance using
1600−-- 'withScientific' if you want to allow larger inputs.
1253+ parseJSON = withObject "Rational" $ \obj -> do
1254+ numerator <- obj .: "numerator"
1255+ denominator <- obj .: "denominator"
1256+ if denominator == 0
1257+ then fail "Ratio denominator was 0"
1258+ else pure $ numerator % denominator
1259+ {-# INLINE parseJSON #-}
1260+
1261+-- | /WARNING:/ Only parse fixed-precision numbers from trusted input
1262+-- since an attacker could easily fill up the memory of the target
1263+-- system by specifying a scientific number with a big exponent like
1264+-- @1e1000000000@.
16011265instance HasResolution a => FromJSON (Fixed a) where
1602− parseJSON = prependContext "Fixed" . withBoundedScientific' (pure . realToFrac)
1266+ parseJSON = withScientific "Fixed" $ pure . realToFrac
16031267 {-# INLINE parseJSON #-}
16041268
16051269instance FromJSON Int where
@@ -1609,10 +1273,10 @@ instance FromJSON Int where
16091273instance FromJSONKey Int where
16101274 fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Int"
16111275
1612−-- | This instance includes a bounds check to prevent maliciously
1613−-- large inputs to fill up the memory of the target system. You can
1614−-- newtype 'Scientific' and provide your own instance using
1615−-- 'withScientific' if you want to allow larger inputs.
1276+-- | /WARNING:/ Only parse Integers from trusted input since an
1277+-- attacker could easily fill up the memory of the target system by
1278+-- specifying a scientific number with a big exponent like
1279+-- @1e1000000000@.
16161280instance FromJSON Integer where
16171281 parseJSON = parseIntegral "Integer"
16181282 {-# INLINE parseJSON #-}
@@ -1622,20 +1286,19 @@ instance FromJSONKey Integer where
16221286
16231287instance FromJSON Natural where
16241288 parseJSON value = do
1625− integer <- parseIntegral "Natural" value
1626− parseNatural integer
1289+ integer :: Integer <- parseIntegral "Natural" value
1290+ if integer < 0 then
1291+ fail $ "expected Natural, encountered negative number " <> show integer
1292+ else
1293+ pure $ fromIntegral integer
16271294
16281295instance FromJSONKey Natural where
16291296 fromJSONKey = FromJSONKeyTextParser $ \text -> do
1630− integer <- parseIntegralText "Natural" text
1631− parseNatural integer
1632−
1633−parseNatural :: Integer -> Parser Natural
1634−parseNatural integer =
1635− if integer < 0 then
1636− fail $ "parsing Natural failed, unexpected negative number " <> show integer
1637− else
1638− pure $ fromIntegral integer
1297+ integer :: Integer <- parseIntegralText "Natural" text
1298+ if integer < 0 then
1299+ fail $ "expected Natural, encountered negative number " <> show integer
1300+ else
1301+ pure $ fromIntegral integer
16391302
16401303instance FromJSON Int8 where
16411304 parseJSON = parseBoundedIntegral "Int8"
@@ -1732,17 +1395,17 @@ parseVersionText = go . readP_to_S parseVersion . unpack
17321395 where
17331396 go [(v,[])] = return v
17341397 go (_ : xs) = go xs
1735− go _ = fail "parsing Version failed"
1398+ go _ = fail "could not parse Version"
17361399
17371400-------------------------------------------------------------------------------
17381401-- semigroups NonEmpty
17391402-------------------------------------------------------------------------------
17401403
17411404instance FromJSON1 NonEmpty where
1742− liftParseJSON p _ = withArray "NonEmpty" $
1405+ liftParseJSON p _ = withArray "NonEmpty a" $
17431406 (>>= ne) . Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
17441407 where
1745− ne [] = fail "parsing NonEmpty failed, unexpected empty list"
1408+ ne [] = fail "Expected a NonEmpty but got an empty list"
17461409 ne (x:xs) = pure (x :| xs)
17471410 {-# INLINE liftParseJSON #-}
17481411
@@ -1763,7 +1426,7 @@ instance FromJSON Scientific where
17631426-------------------------------------------------------------------------------
17641427
17651428instance FromJSON1 DList.DList where
1766− liftParseJSON p _ = withArray "DList" $
1429+ liftParseJSON p _ = withArray "DList a" $
17671430 fmap DList.fromList .
17681431 Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
17691432 {-# INLINE liftParseJSON #-}
@@ -1840,7 +1503,7 @@ instance (FromJSON1 f, FromJSON1 g) => FromJSON1 (Sum f g) where
18401503 inr = "InR"
18411504
18421505 liftParseJSON _ _ _ = fail $
1843− "parsing Sum failed, expected an object with a single property " ++
1506+ "expected an object with a single property " ++
18441507 "where the property key should be either " ++
18451508 "\"InL\" or \"InR\""
18461509 {-# INLINE liftParseJSON #-}
@@ -1854,7 +1517,7 @@ instance (FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Sum f g a) where
18541517-------------------------------------------------------------------------------
18551518
18561519instance FromJSON1 Seq.Seq where
1857− liftParseJSON p _ = withArray "Seq" $
1520+ liftParseJSON p _ = withArray "Seq a" $
18581521 fmap Seq.fromList .
18591522 Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
18601523 {-# INLINE liftParseJSON #-}
@@ -1888,13 +1551,13 @@ instance FromJSON a => FromJSON (IntMap.IntMap a) where
18881551
18891552instance (FromJSONKey k, Ord k) => FromJSON1 (M.Map k) where
18901553 liftParseJSON p _ = case fromJSONKey of
1891− FromJSONKeyCoerce _ -> withObject "Map" $
1554+ FromJSONKeyCoerce _-> withObject "Map k v" $
18921555 fmap (H.foldrWithKey (M.insert . unsafeCoerce) M.empty) . H.traverseWithKey (\k v -> p v <?> Key k)
1893− FromJSONKeyText f -> withObject "Map" $
1556+ FromJSONKeyText f -> withObject "Map k v" $
18941557 fmap (H.foldrWithKey (M.insert . f) M.empty) . H.traverseWithKey (\k v -> p v <?> Key k)
1895− FromJSONKeyTextParser f -> withObject "Map" $
1558+ FromJSONKeyTextParser f -> withObject "Map k v" $
18961559 H.foldrWithKey (\k v m -> M.insert <$> f k <?> Key k <*> p v <?> Key k <*> m) (pure M.empty)
1897− FromJSONKeyValue f -> withArray "Map" $ \arr ->
1560+ FromJSONKeyValue f -> withArray "Map k v" $ \arr ->
18981561 fmap M.fromList . Tr.sequence .
18991562 zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr
19001563 {-# INLINE liftParseJSON #-}
@@ -1922,18 +1585,18 @@ instance (FromJSON v) => FromJSON (Tree.Tree v) where
19221585
19231586instance FromJSON UUID.UUID where
19241587 parseJSON = withText "UUID" $
1925− maybe (fail "invalid UUID") pure . UUID.fromText
1588+ maybe (fail "Invalid UUID") pure . UUID.fromText
19261589
19271590instance FromJSONKey UUID.UUID where
19281591 fromJSONKey = FromJSONKeyTextParser $
1929− maybe (fail "invalid UUID") pure . UUID.fromText
1592+ maybe (fail "Invalid UUID") pure . UUID.fromText
19301593
19311594-------------------------------------------------------------------------------
19321595-- vector
19331596-------------------------------------------------------------------------------
19341597
19351598instance FromJSON1 Vector where
1936− liftParseJSON p _ = withArray "Vector" $
1599+ liftParseJSON p _ = withArray "Vector a" $
19371600 V.mapM (uncurry $ parseIndexedJSON p) . V.indexed
19381601 {-# INLINE liftParseJSON #-}
19391602
@@ -1947,14 +1610,14 @@ vectorParseJSON s = withArray s $ fmap V.convert . V.mapM (uncurry $ parseIndexe
19471610{-# INLINE vectorParseJSON #-}
19481611
19491612instance (Storable a, FromJSON a) => FromJSON (VS.Vector a) where
1950− parseJSON = vectorParseJSON "Data.Vector.Storable.Vector"
1613+ parseJSON = vectorParseJSON "Data.Vector.Storable.Vector a"
19511614
19521615instance (VP.Prim a, FromJSON a) => FromJSON (VP.Vector a) where
1953− parseJSON = vectorParseJSON "Data.Vector.Primitive.Vector"
1616+ parseJSON = vectorParseJSON "Data.Vector.Primitive.Vector a"
19541617 {-# INLINE parseJSON #-}
19551618
19561619instance (VG.Vector VU.Vector a, FromJSON a) => FromJSON (VU.Vector a) where
1957− parseJSON = vectorParseJSON "Data.Vector.Unboxed.Vector"
1620+ parseJSON = vectorParseJSON "Data.Vector.Unboxed.Vector a"
19581621 {-# INLINE parseJSON #-}
19591622
19601623-------------------------------------------------------------------------------
@@ -1968,13 +1631,13 @@ instance (Eq a, Hashable a, FromJSON a) => FromJSON (HashSet.HashSet a) where
19681631
19691632instance (FromJSONKey k, Eq k, Hashable k) => FromJSON1 (H.HashMap k) where
19701633 liftParseJSON p _ = case fromJSONKey of
1971− FromJSONKeyCoerce _ -> withObject "HashMap ~Text" $
1634+ FromJSONKeyCoerce _ -> withObject "HashMap ~Text v" $
19721635 uc . H.traverseWithKey (\k v -> p v <?> Key k)
1973− FromJSONKeyText f -> withObject "HashMap" $
1636+ FromJSONKeyText f -> withObject "HashMap k v" $
19741637 fmap (mapKey f) . H.traverseWithKey (\k v -> p v <?> Key k)
1975− FromJSONKeyTextParser f -> withObject "HashMap" $
1638+ FromJSONKeyTextParser f -> withObject "HashMap k v" $
19761639 H.foldrWithKey (\k v m -> H.insert <$> f k <?> Key k <*> p v <?> Key k <*> m) (pure H.empty)
1977− FromJSONKeyValue f -> withArray "Map" $ \arr ->
1640+ FromJSONKeyValue f -> withArray "Map k v" $ \arr ->
19781641 fmap H.fromList . Tr.sequence .
19791642 zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr
19801643 where
@@ -1997,33 +1660,11 @@ instance FromJSON DotNetTime where
19971660 parseJSON = withText "DotNetTime" $ \t ->
19981661 let (s,m) = T.splitAt (T.length t - 5) t
19991662 t' = T.concat [s,".",m]
2000− in case parseTimeM True defaultTimeLocale "/Date(%s%Q)/" (unpack t') of
1663+ in case parseTime defaultTimeLocale "/Date(%s%Q)/" (unpack t') of
20011664 Just d -> pure (DotNetTime d)
20021665 _ -> fail "could not parse .NET time"
20031666 {-# INLINE parseJSON #-}
20041667
2005−-------------------------------------------------------------------------------
2006−-- primitive
2007−-------------------------------------------------------------------------------
2008−
2009−instance FromJSON a => FromJSON (PM.Array a) where
2010− -- note: we could do better than this if vector exposed the data
2011− -- constructor in Data.Vector.
2012− parseJSON = fmap Exts.fromList . parseJSON
2013−
2014−instance FromJSON a => FromJSON (PM.SmallArray a) where
2015− parseJSON = fmap Exts.fromList . parseJSON
2016−
2017−#if MIN_VERSION_primitive(0,6,4)
2018−instance (PM.Prim a,FromJSON a) => FromJSON (PM.PrimArray a) where
2019− parseJSON = fmap Exts.fromList . parseJSON
2020−
2021−#if !MIN_VERSION_primitive(0,7,0)
2022−instance (PM.PrimUnlifted a,FromJSON a) => FromJSON (PM.UnliftedArray a) where
2023− parseJSON = fmap Exts.fromList . parseJSON
2024−#endif
2025−#endif
2026−
20271668-------------------------------------------------------------------------------
20281669-- time
20291670-------------------------------------------------------------------------------
@@ -2074,56 +1715,22 @@ instance FromJSONKey UTCTime where
20741715 fromJSONKey = FromJSONKeyTextParser (Time.run Time.utcTime)
20751716
20761717
2077−-- | This instance includes a bounds check to prevent maliciously
2078−-- large inputs to fill up the memory of the target system. You can
2079−-- newtype 'Scientific' and provide your own instance using
2080−-- 'withScientific' if you want to allow larger inputs.
1718+-- | /WARNING:/ Only parse lengths of time from trusted input
1719+-- since an attacker could easily fill up the memory of the target
1720+-- system by specifying a scientific number with a big exponent like
1721+-- @1e1000000000@.
20811722instance FromJSON NominalDiffTime where
2082− parseJSON = withBoundedScientific "NominalDiffTime" $ pure . realToFrac
1723+ parseJSON = withScientific "NominalDiffTime" $ pure . realToFrac
20831724 {-# INLINE parseJSON #-}
20841725
20851726
2086−-- | This instance includes a bounds check to prevent maliciously
2087−-- large inputs to fill up the memory of the target system. You can
2088−-- newtype 'Scientific' and provide your own instance using
2089−-- 'withScientific' if you want to allow larger inputs.
1727+-- | /WARNING:/ Only parse lengths of time from trusted input
1728+-- since an attacker could easily fill up the memory of the target
1729+-- system by specifying a scientific number with a big exponent like
1730+-- @1e1000000000@.
20901731instance FromJSON DiffTime where
2091− parseJSON = withBoundedScientific "DiffTime" $ pure . realToFrac
2092− {-# INLINE parseJSON #-}
2093−
2094−instance FromJSON SystemTime where
2095− parseJSON v = prependContext "SystemTime" $ do
2096− n <- parseJSON v
2097− let n' = floor (n * fromInteger (resolution n) :: Nano)
2098− let (secs, nano) = n' `divMod` resolution n
2099− return (MkSystemTime (fromInteger secs) (fromInteger nano))
2100−
2101−instance FromJSON CalendarDiffTime where
2102− parseJSON = withObject "CalendarDiffTime" $ \obj -> CalendarDiffTime
2103− <$> obj .: "months"
2104− <*> obj .: "time"
2105−
2106−instance FromJSON CalendarDiffDays where
2107− parseJSON = withObject "CalendarDiffDays" $ \obj -> CalendarDiffDays
2108− <$> obj .: "months"
2109− <*> obj .: "days"
2110−
2111−instance FromJSON DayOfWeek where
2112− parseJSON = withText "DaysOfWeek" parseDayOfWeek
2113−
2114−parseDayOfWeek :: T.Text -> Parser DayOfWeek
2115−parseDayOfWeek t = case T.toLower t of
2116− "monday" -> return Monday
2117− "tuesday" -> return Tuesday
2118− "wednesday" -> return Wednesday
2119− "thursday" -> return Thursday
2120− "friday" -> return Friday
2121− "saturday" -> return Saturday
2122− "sunday" -> return Sunday
2123− _ -> fail "Invalid week day"
2124−
2125−instance FromJSONKey DayOfWeek where
2126− fromJSONKey = FromJSONKeyTextParser parseDayOfWeek
1732+ parseJSON = withScientific "DiffTime" $ pure . realToFrac
1733+ {-# INLINE parseJSON #-}
21271734
21281735-------------------------------------------------------------------------------
21291736-- base Monoid/Semigroup
@@ -2245,15 +1852,14 @@ instance FromJSON a => FromJSON (Semigroup.Option a) where
22451852
22461853instance FromJSON1 Proxy where
22471854 {-# INLINE liftParseJSON #-}
2248− liftParseJSON _ _ = fromNull "Proxy" Proxy
1855+ liftParseJSON _ _ Null = pure Proxy
1856+ liftParseJSON _ _ v = typeMismatch "Proxy" v
22491857
22501858instance FromJSON (Proxy a) where
22511859 {-# INLINE parseJSON #-}
2252− parseJSON = fromNull "Proxy" Proxy
1860+ parseJSON Null = pure Proxy
1861+ parseJSON v = typeMismatch "Proxy" v
22531862
2254−fromNull :: String -> a -> Value -> Parser a
2255−fromNull _ a Null = pure a
2256−fromNull c _ v = prependContext c (typeMismatch "Null" v)
22571863
22581864instance FromJSON2 Tagged where
22591865 liftParseJSON2 _ _ p _ = fmap Tagged . p
@@ -2280,7 +1886,10 @@ instance (FromJSON a, FromJSON b, FromJSON c) => FromJSONKey (a,b,c)
22801886instance (FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSONKey (a,b,c,d)
22811887
22821888instance FromJSONKey Char where
2283− fromJSONKey = FromJSONKeyTextParser parseChar
1889+ fromJSONKey = FromJSONKeyTextParser $ \t ->
1890+ if T.length t == 1
1891+ then return (T.index t 0)
1892+ else typeMismatch "Expected Char but String didn't contain exactly one character" (String t)
22841893 fromJSONKeyList = FromJSONKeyText T.unpack
22851894
22861895instance (FromJSONKey a, FromJSON a) => FromJSONKey [a] where