mirror of
https://github.com/facebook/sapling.git
synced 2024-10-11 01:07:15 +03:00
treedirstate: add Store and StoreView traits
These traits represent abstract store objects than can store arbitrary data blocks with store-generated indexes. A NullStore implementation is provided which acts an always-empty StoreView. Differential Revision: https://phab.mercurial-scm.org/D1397
This commit is contained in:
Mark Thomas
parent
5931d6cf5d
commit
1537d3833e
63
rust/treedirstate/Cargo.lock
generated
63
rust/treedirstate/Cargo.lock
generated
@ -6,11 +6,53 @@ dependencies = [
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"memchr 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "backtrace"
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version = "0.3.3"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
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"backtrace-sys 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
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"cfg-if 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
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"dbghelp-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
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"kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
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"libc 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
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"rustc-demangle 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
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"winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "backtrace-sys"
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version = "0.1.16"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
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"cc 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
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"libc 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "bitflags"
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version = "0.7.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
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name = "cc"
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version = "1.0.3"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
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name = "cfg-if"
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version = "0.1.2"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
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name = "dbghelp-sys"
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version = "0.2.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
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"winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
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"winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "either"
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version = "1.4.0"
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@ -25,6 +67,14 @@ dependencies = [
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"regex 0.1.80 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "error-chain"
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version = "0.11.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
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"backtrace 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "fuchsia-zircon"
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version = "0.2.1"
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@ -112,10 +162,16 @@ name = "regex-syntax"
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version = "0.3.9"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
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name = "rustc-demangle"
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version = "0.1.5"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
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name = "rusttreedirstate"
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version = "0.1.0"
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dependencies = [
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"error-chain 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
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"itertools 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
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"quickcheck 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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@ -154,9 +210,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
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[metadata]
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"checksum aho-corasick 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ca972c2ea5f742bfce5687b9aef75506a764f61d37f8f649047846a9686ddb66"
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"checksum backtrace 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "99f2ce94e22b8e664d95c57fff45b98a966c2252b60691d0b7aeeccd88d70983"
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"checksum backtrace-sys 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)" = "44585761d6161b0f57afc49482ab6bd067e4edef48c12a152c237eb0203f7661"
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"checksum bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "aad18937a628ec6abcd26d1489012cc0e18c21798210f491af69ded9b881106d"
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"checksum cc 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a9b13a57efd6b30ecd6598ebdb302cca617930b5470647570468a65d12ef9719"
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"checksum cfg-if 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d4c819a1287eb618df47cc647173c5c4c66ba19d888a6e50d605672aed3140de"
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"checksum dbghelp-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "97590ba53bcb8ac28279161ca943a924d1fd4a8fb3fa63302591647c4fc5b850"
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"checksum either 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "740178ddf48b1a9e878e6d6509a1442a2d42fd2928aae8e7a6f8a36fb01981b3"
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"checksum env_logger 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "15abd780e45b3ea4f76b4e9a26ff4843258dd8a3eed2775a0e7368c2e7936c2f"
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"checksum error-chain 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ff511d5dc435d703f4971bc399647c9bc38e20cb41452e3b9feb4765419ed3f3"
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"checksum fuchsia-zircon 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "f6c0581a4e363262e52b87f59ee2afe3415361c6ec35e665924eb08afe8ff159"
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"checksum fuchsia-zircon-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "43f3795b4bae048dc6123a6b972cadde2e676f9ded08aef6bb77f5f157684a82"
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"checksum itertools 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "2c52051d3fd3b505796a0ee90f2e5ec43213808585e8adc4d0182492cf62751a"
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@ -168,6 +230,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
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"checksum rand 0.3.18 (registry+https://github.com/rust-lang/crates.io-index)" = "6475140dfd8655aeb72e1fd4b7a1cc1c202be65d71669476e392fe62532b9edd"
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"checksum regex 0.1.80 (registry+https://github.com/rust-lang/crates.io-index)" = "4fd4ace6a8cf7860714a2c2280d6c1f7e6a413486c13298bbc86fd3da019402f"
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"checksum regex-syntax 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)" = "f9ec002c35e86791825ed294b50008eea9ddfc8def4420124fbc6b08db834957"
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"checksum rustc-demangle 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "aee45432acc62f7b9a108cc054142dac51f979e69e71ddce7d6fc7adf29e817e"
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"checksum thread-id 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a9539db560102d1cef46b8b78ce737ff0bb64e7e18d35b2a5688f7d097d0ff03"
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"checksum thread_local 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)" = "8576dbbfcaef9641452d5cf0df9b0e7eeab7694956dd33bb61515fb8f18cfdd5"
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"checksum utf8-ranges 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a1ca13c08c41c9c3e04224ed9ff80461d97e121589ff27c753a16cb10830ae0f"
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@ -10,6 +10,9 @@ lto = true
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name = "rusttreedirstate"
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crate-type = ["cdylib"]
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[dependencies]
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error-chain = "*"
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[dev-dependencies]
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itertools = "0.7.2"
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quickcheck = "*"
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16
rust/treedirstate/src/errors.rs
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16
rust/treedirstate/src/errors.rs
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@ -0,0 +1,16 @@
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// Copyright Facebook, Inc. 2017
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//! Errors.
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error_chain! {
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errors {
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InvalidStoreId(id: u64) {
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description("invalid store id"),
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display("invalid store id: {}", id),
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}
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}
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foreign_links {
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Io(::std::io::Error);
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Utf8(::std::str::Utf8Error);
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Utf8String(::std::string::FromUtf8Error);
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}
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}
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@ -12,6 +12,9 @@
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//! The directory state also stores files that are in the working copy parent manifest but have
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//! been marked as removed.
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#[macro_use]
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extern crate error_chain;
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#[cfg(test)]
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extern crate itertools;
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@ -19,4 +22,8 @@ extern crate itertools;
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#[macro_use]
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extern crate quickcheck;
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pub mod errors;
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pub mod store;
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pub mod vecmap;
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pub use errors::*;
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103
rust/treedirstate/src/store.rs
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103
rust/treedirstate/src/store.rs
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@ -0,0 +1,103 @@
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// Copyright Facebook, Inc. 2017
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//! Trait defining an append-only storage system.
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use errors::*;
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use std::borrow::Cow;
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#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
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pub struct BlockId(u64);
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/// Append-only storage. Blocks of data may be stored in an instance of a Store. Once written,
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/// blocks are immutable.
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pub trait Store {
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/// Append a new block of data to the store. Returns the ID of the block. Note that blocks
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/// may be buffered until `flush` is called.
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fn append(&mut self, data: &[u8]) -> Result<BlockId>;
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/// Flush all appended blocks to the backing store.
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fn flush(&mut self) -> Result<()>;
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}
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/// Read-only view of a store.
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pub trait StoreView {
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/// Read a block of data from the store. Blocks are immutiable, so the result may be a
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/// reference to the internal copy of the data in the store.
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fn read<'a>(&'a self, id: BlockId) -> Result<Cow<'a, [u8]>>;
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}
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/// Null implementation of a store. This cannot be used to store new blocks of data, and returns
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/// an error if any attempts to read are made.
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pub struct NullStore;
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impl NullStore {
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pub fn new() -> NullStore {
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NullStore
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}
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}
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impl StoreView for NullStore {
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fn read<'a>(&'a self, id: BlockId) -> Result<Cow<'a, [u8]>> {
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bail!(ErrorKind::InvalidStoreId(id.0))
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}
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}
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#[cfg(test)]
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pub mod tests {
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use std::collections::HashMap;
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use errors::*;
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use store::{BlockId, Store, StoreView};
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use std::borrow::Cow;
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/// Define a Store to be used in tests. This doesn't store the data on disk, but rather
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/// keeps it in memory in a hash map.
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pub struct MapStore {
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next_id: BlockId,
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data: HashMap<BlockId, Vec<u8>>,
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}
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impl MapStore {
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pub fn new() -> MapStore {
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// Initial ID is set to 24 to simulate a header.
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MapStore {
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next_id: BlockId(24),
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data: HashMap::new(),
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}
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}
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}
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impl Store for MapStore {
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fn append(&mut self, data: &[u8]) -> Result<BlockId> {
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let id = self.next_id;
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self.data.insert(id, data.to_vec());
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self.next_id.0 += data.len() as u64;
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Ok(id)
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}
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fn flush(&mut self) -> Result<()> {
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Ok(())
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}
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}
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impl StoreView for MapStore {
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fn read<'a>(&'a self, id: BlockId) -> Result<Cow<'a, [u8]>> {
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match self.data.get(&id) {
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Some(data) => Ok(Cow::from(data.as_slice())),
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None => bail!(ErrorKind::InvalidStoreId(id.0)),
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}
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}
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}
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#[test]
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fn basic_test() {
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let mut ms = MapStore::new();
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let key1 = ms.append("12345".as_bytes()).expect("append key1");
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let key2 = ms.append("67890".as_bytes()).expect("append key2");
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ms.flush().expect("flush");
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assert_eq!(ms.read(key2).unwrap(), "67890".as_bytes());
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assert_eq!(ms.read(key1).unwrap(), "12345".as_bytes());
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assert_eq!(
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ms.read(BlockId(999)).unwrap_err().to_string(),
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"invalid store id: 999"
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);
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}
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}
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