dirstate-tree: Use HashMap instead of BTreeMap BTreeMap has the advantage of its "natural" iteration order being the one we need in the status algorithm. With HashMap however, iteration order is undefined so we need to allocate a Vec and sort it explicitly. Unfortunately many BTreeMap operations are slower than in HashMap, and skipping that extra allocation and sort is not enough to compensate. Switching to HashMap + sort makes `hg status` 17% faster in one test case, as measure with hyperfine: ``` Benchmark #1: ../hg2/hg status -R $REPO --config=experimental.dirstate-tree.in-memory=1 Time (mean ? ?): 765.0 ms ? 8.8 ms [User: 1.352 s, System: 0.747 s] Range (min ? max): 751.8 ms ? 778.7 ms 10 runs Benchmark #2: ./hg status -R $REPO --config=experimental.dirstate-tree.in-memory=1 Time (mean ? ?): 651.8 ms ? 9.9 ms [User: 1.251 s, System: 0.799 s] Range (min ? max): 642.2 ms ? 671.8 ms 10 runs Summary './hg status -R $REPO --config=experimental.dirstate-tree.in-memory=1' ran 1.17 ? 0.02 times faster than '../hg2/hg status -R $REPO --config=experimental.dirstate-tree.in-memory=1' ``` * ./hg is this revision * ../hg2/hg is its parent * $REPO is an old snapshot of mozilla-central Differential Revision: https://phab.mercurial-scm.org/D10553

// debugdata.rs
//
// Copyright 2020 Antoine Cezar <antoine.cezar@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::repo::Repo;
use crate::revlog::revlog::{Revlog, RevlogError};

/// Kind of data to debug
#[derive(Debug, Copy, Clone)]
pub enum DebugDataKind {
    Changelog,
    Manifest,
}

/// Dump the contents data of a revision.
pub fn debug_data(
    repo: &Repo,
    revset: &str,
    kind: DebugDataKind,
) -> Result<Vec<u8>, RevlogError> {
    let index_file = match kind {
        DebugDataKind::Changelog => "00changelog.i",
        DebugDataKind::Manifest => "00manifest.i",
    };
    let revlog = Revlog::open(repo, index_file, None)?;
    let rev =
        crate::revset::resolve_rev_number_or_hex_prefix(revset, &revlog)?;
    let data = revlog.get_rev_data(rev)?;
    Ok(data)
}