view rust/hg-core/src/lib.rs @ 43438:a77d4fe347a4

rust-matchers: add `Matcher` trait and implement `AlwaysMatcher`

In our quest of a faster Mercurial, we have arrived at the point where we need
to implement the matchers in Rust.
This RFC mainly for the `Matcher` trait to see if the changes proposed feel
fine to people with more experience on the matter. While the `AlwaysMatcher`
implementation is here as a trivial example, it should be the first step
towards matchers use in Rust as it is currently the only supported one.

Notable changes:
    - `exact` is renamed to `exact_match`
    - enums for `visit*` methods with `Recursive` instead of `'all'`, etc.
    - a new `roots`, separate from `file_set`
    - no `bad`, `explicitdir` or `traversedir` functions as they can be passed
      to the high functions instead of the matchers

Thanks to Martin for suggesting the last two (most important) changes and for
reaching out to help a few weeks ago.

Differential Revision: https://phab.mercurial-scm.org/D7178

// Copyright 2018 Georges Racinet <[e-mail]>
//
// 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 use ancestors::{AncestorsIterator, LazyAncestors, MissingAncestors};
mod dirstate;
pub mod discovery;
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,
    CopyMap, CopyMapIter, DirstateEntry, DirstateParents, EntryState,
    StateMap, StateMapIter,
};
mod filepatterns;
pub mod matchers;
pub mod utils;

use crate::utils::hg_path::HgPathBuf;
pub use filepatterns::{
    build_single_regex, read_pattern_file, PatternSyntax, PatternTuple,
};

/// Mercurial revision numbers
///
/// As noted in revlog.c, revision numbers are actually encoded in
/// 4 bytes, and are liberally converted to ints, whence the i32
pub type Revision = i32;

/// Marker expressing the absence of a parent
///
/// Independently of the actual representation, `NULL_REVISION` is guaranteed
/// to be smaller that all existing revisions.
pub const NULL_REVISION: Revision = -1;

/// Same as `mercurial.node.wdirrev`
///
/// This is also equal to `i32::max_value()`, but it's better to spell
/// it out explicitely, same as in `mercurial.node`
pub const WORKING_DIRECTORY_REVISION: Revision = 0x7fffffff;

/// The simplest expression of what we need of Mercurial DAGs.
pub trait Graph {
    /// Return the two parents of the given `Revision`.
    ///
    /// Each of the parents can be independently `NULL_REVISION`
    fn parents(&self, rev: Revision) -> Result<[Revision; 2], GraphError>;
}

pub type LineNumber = usize;

#[derive(Clone, Debug, PartialEq)]
pub enum GraphError {
    ParentOutOfRange(Revision),
    WorkingDirectoryUnsupported,
}

#[derive(Clone, Debug, PartialEq)]
pub enum DirstateParseError {
    TooLittleData,
    Overflow,
    CorruptedEntry(String),
    Damaged,
}

impl From<std::io::Error> for DirstateParseError {
    fn from(e: std::io::Error) -> Self {
        DirstateParseError::CorruptedEntry(e.to_string())
    }
}

impl ToString for DirstateParseError {
    fn to_string(&self) -> String {
        use crate::DirstateParseError::*;
        match self {
            TooLittleData => "Too little data for dirstate.".to_string(),
            Overflow => "Overflow in dirstate.".to_string(),
            CorruptedEntry(e) => format!("Corrupted entry: {:?}.", e),
            Damaged => "Dirstate appears to be damaged.".to_string(),
        }
    }
}

#[derive(Debug, PartialEq)]
pub enum DirstatePackError {
    CorruptedEntry(String),
    CorruptedParent,
    BadSize(usize, usize),
}

impl From<std::io::Error> for DirstatePackError {
    fn from(e: std::io::Error) -> Self {
        DirstatePackError::CorruptedEntry(e.to_string())
    }
}
#[derive(Debug, PartialEq)]
pub enum DirstateMapError {
    PathNotFound(HgPathBuf),
    EmptyPath,
}

pub enum DirstateError {
    Parse(DirstateParseError),
    Pack(DirstatePackError),
    Map(DirstateMapError),
    IO(std::io::Error),
}

impl From<DirstateParseError> for DirstateError {
    fn from(e: DirstateParseError) -> Self {
        DirstateError::Parse(e)
    }
}

impl From<DirstatePackError> for DirstateError {
    fn from(e: DirstatePackError) -> Self {
        DirstateError::Pack(e)
    }
}

#[derive(Debug)]
pub enum PatternError {
    UnsupportedSyntax(String),
}

#[derive(Debug)]
pub enum PatternFileError {
    IO(std::io::Error),
    Pattern(PatternError, LineNumber),
}

impl From<std::io::Error> for PatternFileError {
    fn from(e: std::io::Error) -> Self {
        PatternFileError::IO(e)
    }
}

impl From<DirstateMapError> for DirstateError {
    fn from(e: DirstateMapError) -> Self {
        DirstateError::Map(e)
    }
}

impl From<std::io::Error> for DirstateError {
    fn from(e: std::io::Error) -> Self {
        DirstateError::IO(e)
    }
}