view rust/hg-core/src/operations/debugdata.rs @ 48225:0cc69017d47f

rhg: stop manifest traversal when no more files are needed Stopping the traversal early can skip a significant part of the manifest traversal, to avoid some of its cost. The worst-case benchmarks are favorable, as well. Running [hg cat] on the last file in the manifest of a large repo, I'm seeing a ~4ms improvement (150ms -> 146ms), so this time is now almost indistinguishable from the baseline ("brute force") implementation. Running [hg cat] on ~220 files together with the last file of the repo is further improved by ~5ms or so. I suspect the raw performance improvements are caused by splitting the manifest search and the file data access into separate phases, instead of interleaving them. Differential Revision: https://phab.mercurial-scm.org/D11616
author Arseniy Alekseyev <aalekseyev@janestreet.com>
date Tue, 05 Oct 2021 15:10:42 +0100
parents b274aa2f20fd
children f2f57724d4eb
line wrap: on
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// 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)
}