view contrib/python-hook-examples.py @ 46775:c94fa884240b

rust: Preallocate the returned `Vec` in `utils::files::relativize_path`

Profiling `rhg files > /dev/null` on an old snapshot of mozilla-central
(with `perf` and the Firefox Profiler:
https://github.com/firefox-devtools/profiler/blob/main/docs-user/guide-perf-profiling.md)
showed non-trivial time spend in this function and in `realloc`.

This change makes the wall-clock time for that process on my machine
go from ~190 ms to ~150 ms.

Differential Revision: https://phab.mercurial-scm.org/D10199

'''
Examples of useful python hooks for Mercurial.
'''
from __future__ import absolute_import
from mercurial import (
    patch,
    util,
)


def diffstat(ui, repo, **kwargs):
    """Example usage:

    [hooks]
    commit.diffstat = python:/path/to/this/file.py:diffstat
    changegroup.diffstat = python:/path/to/this/file.py:diffstat
    """
    if kwargs.get('parent2'):
        return
    node = kwargs['node']
    first = repo[node].p1().node()
    if 'url' in kwargs:
        last = repo.changelog.tip()
    else:
        last = node
    diff = patch.diff(repo, first, last)
    ui.write(patch.diffstat(util.iterlines(diff)))