Mercurial > hg
view rust/hg-core/src/dirstate.rs @ 45562:b51167d70f5a
rust: add `dirstate_tree` module
Mercurial needs to represent the filesystem hierarchy on which it operates, for
example in the dirstate. Its current on-disk representation is an unsorted, flat
structure that gets transformed in the current Rust code into a `HashMap`.
This loses the hierarchical information of the dirstate, leading to some
unfortunate performance and algorithmic compromises.
This module adds an implementation of a radix tree that is specialized for
representing the dirstate: its unit is the path component. I have made no
efforts to optimize either its memory footprint or its insertion speed: they're
pretty bad for now.
Following will be a few patches that modify the dirstate.status logic to use
that new hierarchical information, fixing issue 6335 in the same swing.
Differential Revision: https://phab.mercurial-scm.org/D9085
author | Raphaël Gomès <rgomes@octobus.net> |
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date | Fri, 25 Sep 2020 17:51:34 +0200 |
parents | 5ac243a92e37 |
children | e604a3c03ab9 |
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// dirstate module // // 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. use crate::{utils::hg_path::HgPathBuf, DirstateParseError, FastHashMap}; use std::collections::hash_map; use std::convert::TryFrom; pub mod dirs_multiset; pub mod dirstate_map; pub mod dirstate_tree; pub mod parsers; pub mod status; #[derive(Debug, PartialEq, Clone)] pub struct DirstateParents { pub p1: [u8; 20], pub p2: [u8; 20], } /// The C implementation uses all signed types. This will be an issue /// either when 4GB+ source files are commonplace or in 2038, whichever /// comes first. #[derive(Debug, PartialEq, Copy, Clone)] pub struct DirstateEntry { pub state: EntryState, pub mode: i32, pub mtime: i32, pub size: i32, } /// A `DirstateEntry` with a size of `-2` means that it was merged from the /// other parent. This allows revert to pick the right status back during a /// merge. pub const SIZE_FROM_OTHER_PARENT: i32 = -2; pub type StateMap = FastHashMap<HgPathBuf, DirstateEntry>; pub type StateMapIter<'a> = hash_map::Iter<'a, HgPathBuf, DirstateEntry>; pub type CopyMap = FastHashMap<HgPathBuf, HgPathBuf>; pub type CopyMapIter<'a> = hash_map::Iter<'a, HgPathBuf, HgPathBuf>; #[derive(Copy, Clone, Debug, Eq, PartialEq)] pub enum EntryState { Normal, Added, Removed, Merged, Unknown, } impl TryFrom<u8> for EntryState { type Error = DirstateParseError; fn try_from(value: u8) -> Result<Self, Self::Error> { match value { b'n' => Ok(EntryState::Normal), b'a' => Ok(EntryState::Added), b'r' => Ok(EntryState::Removed), b'm' => Ok(EntryState::Merged), b'?' => Ok(EntryState::Unknown), _ => Err(DirstateParseError::CorruptedEntry(format!( "Incorrect entry state {}", value ))), } } } impl Into<u8> for EntryState { fn into(self) -> u8 { match self { EntryState::Normal => b'n', EntryState::Added => b'a', EntryState::Removed => b'r', EntryState::Merged => b'm', EntryState::Unknown => b'?', } } }