##// 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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r49857:c9f44fc9 stable
r49857:c9f44fc9 stable
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status.rs
149 lines | 4.8 KiB | application/rls-services+xml | RustLexer
// status.rs
//
// Copyright 2019 Raphaël Gomès <rgomes@octobus.net>
//
// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.
//! Rust implementation of dirstate.status (dirstate.py).
//! It is currently missing a lot of functionality compared to the Python one
//! and will only be triggered in narrow cases.
use crate::dirstate::entry::TruncatedTimestamp;
use crate::dirstate_tree::on_disk::DirstateV2ParseError;
use crate::{
utils::hg_path::{HgPath, HgPathError},
PatternError,
};
use std::{borrow::Cow, fmt};
/// Wrong type of file from a `BadMatch`
/// Note: a lot of those don't exist on all platforms.
#[derive(Debug, Copy, Clone)]
pub enum BadType {
CharacterDevice,
BlockDevice,
FIFO,
Socket,
Directory,
Unknown,
}
impl fmt::Display for BadType {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.write_str(match self {
BadType::CharacterDevice => "character device",
BadType::BlockDevice => "block device",
BadType::FIFO => "fifo",
BadType::Socket => "socket",
BadType::Directory => "directory",
BadType::Unknown => "unknown",
})
}
}
/// Was explicitly matched but cannot be found/accessed
#[derive(Debug, Copy, Clone)]
pub enum BadMatch {
OsError(i32),
BadType(BadType),
}
/// `Box<dyn Trait>` is syntactic sugar for `Box<dyn Trait + 'static>`, so add
/// an explicit lifetime here to not fight `'static` bounds "out of nowhere".
pub type IgnoreFnType<'a> =
Box<dyn for<'r> Fn(&'r HgPath) -> bool + Sync + 'a>;
/// We have a good mix of owned (from directory traversal) and borrowed (from
/// the dirstate/explicit) paths, this comes up a lot.
pub type HgPathCow<'a> = Cow<'a, HgPath>;
#[derive(Debug, Copy, Clone)]
pub struct StatusOptions {
/// Whether we are on a filesystem with UNIX-like exec flags
pub check_exec: bool,
pub list_clean: bool,
pub list_unknown: bool,
pub list_ignored: bool,
/// Whether to populate `StatusPath::copy_source`
pub list_copies: bool,
/// Whether to collect traversed dirs for applying a callback later.
/// Used by `hg purge` for example.
pub collect_traversed_dirs: bool,
}
#[derive(Default)]
pub struct DirstateStatus<'a> {
/// The current time at the start of the `status()` algorithm, as measured
/// and possibly truncated by the filesystem.
pub filesystem_time_at_status_start: Option<TruncatedTimestamp>,
/// Tracked files whose contents have changed since the parent revision
pub modified: Vec<StatusPath<'a>>,
/// Newly-tracked files that were not present in the parent
pub added: Vec<StatusPath<'a>>,
/// Previously-tracked files that have been (re)moved with an hg command
pub removed: Vec<StatusPath<'a>>,
/// (Still) tracked files that are missing, (re)moved with an non-hg
/// command
pub deleted: Vec<StatusPath<'a>>,
/// Tracked files that are up to date with the parent.
/// Only pupulated if `StatusOptions::list_clean` is true.
pub clean: Vec<StatusPath<'a>>,
/// Files in the working directory that are ignored with `.hgignore`.
/// Only pupulated if `StatusOptions::list_ignored` is true.
pub ignored: Vec<StatusPath<'a>>,
/// Files in the working directory that are neither tracked nor ignored.
/// Only pupulated if `StatusOptions::list_unknown` is true.
pub unknown: Vec<StatusPath<'a>>,
/// Was explicitly matched but cannot be found/accessed
pub bad: Vec<(HgPathCow<'a>, BadMatch)>,
/// Either clean or modified, but we can’t tell from filesystem metadata
/// alone. The file contents need to be read and compared with that in
/// the parent.
pub unsure: Vec<StatusPath<'a>>,
/// Only filled if `collect_traversed_dirs` is `true`
pub traversed: Vec<HgPathCow<'a>>,
/// Whether `status()` made changed to the `DirstateMap` that should be
/// written back to disk
pub dirty: bool,
}
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
pub struct StatusPath<'a> {
pub path: HgPathCow<'a>,
pub copy_source: Option<HgPathCow<'a>>,
}
#[derive(Debug, derive_more::From)]
pub enum StatusError {
/// An invalid path that cannot be represented in Mercurial was found
Path(HgPathError),
/// An invalid "ignore" pattern was found
Pattern(PatternError),
/// Corrupted dirstate
DirstateV2ParseError(DirstateV2ParseError),
}
impl fmt::Display for StatusError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
StatusError::Path(error) => error.fmt(f),
StatusError::Pattern(error) => error.fmt(f),
StatusError::DirstateV2ParseError(_) => {
f.write_str("dirstate-v2 parse error")
}
}
}
}