rust/hg-core/src/lib.rs

rust-dirs-multiset: improve temporary error message

While we wait on a future patch that could verify that the paths passed to
`DirsMultiset` have been audited, we still need to handle this error.
This patch makes it easier to bubble up and makes the error clearer.

Also, this patch introduces the `subslice_index` function that could be useful
for other - albeit niche - purposes.

Differential Revision: https://phab.mercurial-scm.org/D7921

// Copyright 2018-2020 Georges Racinet <[e-mail]>
//           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 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, StatusResult},
    CopyMap, CopyMapIter, DirstateEntry, DirstateParents, EntryState,
    StateMap, StateMapIter,
};
mod filepatterns;
pub mod matchers;
pub mod revlog;
pub use revlog::*;
pub mod utils;

use crate::utils::hg_path::{HgPathBuf, HgPathError};
pub use filepatterns::{
    build_single_regex, read_pattern_file, PatternSyntax, PatternTuple,
};
use std::collections::HashMap;
use twox_hash::RandomXxHashBuilder64;

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(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,
    InvalidPath(HgPathError),
}

impl ToString for DirstateMapError {
    fn to_string(&self) -> String {
        match self {
            DirstateMapError::PathNotFound(_) => {
                "expected a value, found none".to_string()
            }
            DirstateMapError::EmptyPath => "Overflow in dirstate.".to_string(),
            DirstateMapError::InvalidPath(e) => e.to_string(),
        }
    }
}

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)
    }
}