rust/hg-core/src/lib.rs
author Simon Sapin <simon.sapin@octobus.net>
Tue, 30 Mar 2021 14:15:23 +0200
changeset 47093 787ff5d21bcd
parent 46797 bcdcb4423ae3
child 47101 5d62243c7732
permissions -rw-r--r--
dirstate-tree: Make Rust DirstateMap bindings go through a trait object This changeset starts a series that adds an experiment to make status faster by changing the dirstate (first only in memory and later also on disk) to be shaped as a tree matching the directory structure, instead of the current flat collection of entries. The status algorithm can then traverse this tree dirstate at the same time as it traverses the filesystem. We (Octobus) have made prototypes that show promising results but are prone to bitrot. We would like to start upstreaming some experimental Rust code that goes in this direction, but to avoid disrupting users it should only be enabled by some run-time opt-in while keeping the existing dirstate structure and status algorithm as-is. The `DirstateMap` type and `status` function look like the appropriate boundary. This adds a new trait that abstracts everything Python bindings need and makes those bindings go through a `dyn` trait object. Later we’ll have two implementations of this trait, and the same bindings can use either. Differential Revision: https://phab.mercurial-scm.org/D10362

// 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, LazyAncestors, MissingAncestors};
mod dirstate;
pub mod dirstate_tree;
pub mod discovery;
pub mod requirements;
pub mod testing; // unconditionally built, for use from integration tests
pub use dirstate::{
    dirs_multiset::{DirsMultiset, DirsMultisetIter},
    dirstate_map::DirstateMap,
    parsers::{pack_dirstate, parse_dirstate, PARENT_SIZE},
    status::{
        status, BadMatch, BadType, DirstateStatus, HgPathCow, StatusError,
        StatusOptions,
    },
    CopyMap, CopyMapIter, DirstateEntry, DirstateParents, EntryState,
    StateMap, StateMapIter,
};
pub mod copy_tracing;
mod filepatterns;
pub mod matchers;
pub mod repo;
pub mod revlog;
pub use revlog::*;
pub mod config;
pub mod logging;
pub mod operations;
pub mod revset;
pub mod utils;

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),
}

#[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)
            }
        }
    }
}