##// END OF EJS Templates
rust: fix unsound `OwningDirstateMap`...
rust: fix unsound `OwningDirstateMap` As per the previous patch, `OwningDirstateMap` is unsound. Self-referential structs are difficult to implement correctly in Rust since the compiler is free to move structs around as much as it wants to. They are also very rarely needed in practice, so the state-of-the-art on how they should be done within the Rust rules is still a bit new. The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense) of declaring self-referential structs. It is getting a lot attention and was improved very quickly when soundness issues were found in the past: rather than relying on our own (limited) review circle, we might as well use the de-facto common crate to fix this problem. This will give us a much better chance of finding issues should any new ones be discovered as well as the benefit of fewer `unsafe` APIs of our own. I was starting to think about how I would present a safe API to the old struct but soon realized that the callback-based approach was already done in `ouroboros`, along with a lot more care towards refusing incorrect structs. In short: we don't return a mutable reference to the `DirstateMap` anymore, we expect users of its API to pass a `FnOnce` that takes the map as an argument. This allows our `OwningDirstateMap` to control the input and output lifetimes of the code that modifies it to prevent such issues. Changing to `ouroboros` meant changing every API with it, but it is relatively low churn in the end. It correctly identified the example buggy modification of `copy_map_insert` outlined in the previous patch as violating the borrow rules. Differential Revision: https://phab.mercurial-scm.org/D12429

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r49805:11c0411b default
r49857:c9f44fc9 stable
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lib.rs
132 lines | 3.9 KiB | application/rls-services+xml | RustLexer
// 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 use ancestors::{AncestorsIterator, MissingAncestors};
pub mod dirstate;
pub mod dirstate_tree;
pub mod discovery;
pub mod exit_codes;
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;
mod filepatterns;
pub mod matchers;
pub mod repo;
pub mod revlog;
pub use revlog::*;
pub mod config;
pub mod lock;
pub mod logging;
pub mod operations;
pub mod revset;
pub mod utils;
pub mod vfs;
use crate::utils::hg_path::{HgPathBuf, HgPathError};
pub use filepatterns::{
parse_pattern_syntax, read_pattern_file, IgnorePattern,
PatternFileWarning, PatternSyntax,
};
use std::collections::HashMap;
use std::fmt;
use twox_hash::RandomXxHashBuilder64;
/// This is a contract between the `micro-timer` crate and us, to expose
/// the `log` crate as `crate::log`.
use log;
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>;
#[derive(Debug, PartialEq)]
pub enum DirstateMapError {
PathNotFound(HgPathBuf),
EmptyPath,
InvalidPath(HgPathError),
}
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::EmptyPath => {
f.write_str("Overflow in dirstate.")
}
DirstateMapError::InvalidPath(path_error) => path_error.fmt(f),
}
}
}
#[derive(Debug, derive_more::From)]
pub enum DirstateError {
Map(DirstateMapError),
Common(errors::HgError),
}
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)
}
}
}
}