Mercurial > public > mercurial-scm > hg
view rust/hg-core/src/lib.rs @ 52280:f4aede0f01af
rust-manifest: use `memchr` crate for all byte-finding needs
While writing a very dumb manifest diffing algorithm for a proof-of-concept
I saw that `Manifest::find_by_path` was much slower than I was expecting.
It turns out that the Rust stdlib uses slow (all is relative) code when
searching for byte positions for reasons ranging from portability, SIMD
API stability, nobody doing the work, etc. `memch` is much faster for these
purposes, so let's use it.
I was measuring ~670ms of profile time in `find_by_path`, after this patch
it went down to ~230ms.
author | Rapha?l Gom?s <rgomes@octobus.net> |
---|---|
date | Tue, 12 Nov 2024 23:20:04 +0100 |
parents | 65d516db7309 |
children | db065b33fa56 |
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// Copyright 2018-2020 Georges Racinet <georges.racinet@octobus.net> // and Mercurial contributors // // This software may be used and distributed according to the terms of the // GNU General Public License version 2 or any later version. mod ancestors; pub mod dagops; pub mod errors; pub mod narrow; pub mod sparse; pub use ancestors::{AncestorsIterator, MissingAncestors}; pub mod dirstate; pub mod dirstate_tree; pub mod discovery; pub mod exit_codes; pub mod fncache; pub mod requirements; pub mod testing; // unconditionally built, for use from integration tests pub use dirstate::{ dirs_multiset::{DirsMultiset, DirsMultisetIter}, status::{ BadMatch, BadType, DirstateStatus, HgPathCow, StatusError, StatusOptions, }, DirstateEntry, DirstateParents, EntryState, }; pub mod copy_tracing; pub mod filepatterns; pub mod matchers; pub mod repo; pub mod revlog; // Export very common types to make discovery easier pub use revlog::{ BaseRevision, Graph, GraphError, Node, NodePrefix, Revision, UncheckedRevision, NULL_NODE, NULL_NODE_ID, NULL_REVISION, WORKING_DIRECTORY_HEX, WORKING_DIRECTORY_REVISION, }; pub mod checkexec; pub mod config; pub mod lock; pub mod logging; pub mod operations; pub mod progress; pub mod revset; pub mod transaction; pub mod update; pub mod utils; pub mod vfs; use crate::utils::hg_path::{HgPathBuf, HgPathError}; pub use filepatterns::{ parse_pattern_syntax_kind, read_pattern_file, IgnorePattern, PatternFileWarning, PatternSyntax, }; use std::fmt; use std::{collections::HashMap, sync::atomic::AtomicBool}; use twox_hash::RandomXxHashBuilder64; /// Used to communicate with threads spawned from code within this crate that /// they should stop their work (SIGINT was received). pub static INTERRUPT_RECEIVED: AtomicBool = AtomicBool::new(false); pub type LineNumber = usize; /// Rust's default hasher is too slow because it tries to prevent collision /// attacks. We are not concerned about those: if an ill-minded person has /// write access to your repository, you have other issues. pub type FastHashMap<K, V> = HashMap<K, V, RandomXxHashBuilder64>; // TODO: should this be the default `FastHashMap` for all of hg-core, not just // dirstate_tree? How does XxHash compare with AHash, hashbrown’s default? pub type FastHashbrownMap<K, V> = hashbrown::HashMap<K, V, RandomXxHashBuilder64>; #[derive(Debug, PartialEq)] pub enum DirstateMapError { PathNotFound(HgPathBuf), InvalidPath(HgPathError), } impl From<HgPathError> for DirstateMapError { fn from(error: HgPathError) -> Self { Self::InvalidPath(error) } } impl fmt::Display for DirstateMapError { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { match self { DirstateMapError::PathNotFound(_) => { f.write_str("expected a value, found none") } DirstateMapError::InvalidPath(path_error) => path_error.fmt(f), } } } #[derive(Debug, derive_more::From)] pub enum DirstateError { Map(DirstateMapError), Common(errors::HgError), } impl From<HgPathError> for DirstateError { fn from(error: HgPathError) -> Self { Self::Map(DirstateMapError::InvalidPath(error)) } } impl fmt::Display for DirstateError { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { match self { DirstateError::Map(error) => error.fmt(f), DirstateError::Common(error) => error.fmt(f), } } } #[derive(Debug, derive_more::From)] pub enum PatternError { #[from] Path(HgPathError), UnsupportedSyntax(String), UnsupportedSyntaxInFile(String, String, usize), TooLong(usize), #[from] IO(std::io::Error), /// Needed a pattern that can be turned into a regex but got one that /// can't. This should only happen through programmer error. NonRegexPattern(IgnorePattern), } impl fmt::Display for PatternError { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { match self { PatternError::UnsupportedSyntax(syntax) => { write!(f, "Unsupported syntax {}", syntax) } PatternError::UnsupportedSyntaxInFile(syntax, file_path, line) => { write!( f, "{}:{}: unsupported syntax {}", file_path, line, syntax ) } PatternError::TooLong(size) => { write!(f, "matcher pattern is too long ({} bytes)", size) } PatternError::IO(error) => error.fmt(f), PatternError::Path(error) => error.fmt(f), PatternError::NonRegexPattern(pattern) => { write!(f, "'{:?}' cannot be turned into a regex", pattern) } } } }