bisect: avoid copying ancestor list for non-merge commits
During a bisection, hg needs to compute a list of all ancestors for every
candidate commit. This is accomplished via a bottom-up traversal of the set of
candidates, during which each revision's ancestor list is populated using the
ancestor list of its parent(s). Previously, this involved copying the entire
list, which could be very long in if the bisection range was large.
To help improve this, we can observe that each candidate commit is visited
exactly once, at which point its ancestor list is copied into its children's
lists and then dropped. In the case of non-merge commits, a commit's ancestor
list consists exactly of its parent's list plus itself. This means that we can
trivially reuse the parent's existing list for one of its non-merge children,
which avoids copying entirely if that commit is the parent's only child. This
makes bisections over linear ranges of commits much faster.
During some informal testing in the large publicly-available `mozilla-central`
repository, this noticeably sped up bisections over large ranges of history:
Setup:
$ cd mozilla-central
$ hg bisect --reset
$ hg bisect --good 0
$ hg log -r tip -T '{rev}\n'
628417
Test:
$ time hg bisect --bad tip --noupdate
Before:
real 3m35.927s
user 3m35.553s
sys 0m0.319s
After:
real 1m41.142s
user 1m40.810s
sys 0m0.285s
# highlight - syntax highlighting in hgweb, based on Pygments
#
# Copyright 2008, 2009 Patrick Mezard <pmezard@gmail.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
#
# The original module was split in an interface and an implementation
# file to defer pygments loading and speedup extension setup.
"""syntax highlighting for hgweb (requires Pygments)
It depends on the Pygments syntax highlighting library:
http://pygments.org/
There are the following configuration options::
[web]
pygments_style = <style> (default: colorful)
highlightfiles = <fileset> (default: size('<5M'))
highlightonlymatchfilename = <bool> (default False)
``highlightonlymatchfilename`` will only highlight files if their type could
be identified by their filename. When this is not enabled (the default),
Pygments will try very hard to identify the file type from content and any
match (even matches with a low confidence score) will be used.
"""
from . import highlight
from mercurial.hgweb import (
webcommands,
webutil,
)
from mercurial import (
extensions,
pycompat,
)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = b'ships-with-hg-core'
def pygmentize(web, field, fctx, tmpl):
style = web.config(b'web', b'pygments_style', b'colorful')
expr = web.config(b'web', b'highlightfiles', b"size('<5M')")
filenameonly = web.configbool(b'web', b'highlightonlymatchfilename', False)
ctx = fctx.changectx()
m = ctx.matchfileset(fctx.repo().root, expr)
if m(fctx.path()):
highlight.pygmentize(
field, fctx, style, tmpl, guessfilenameonly=filenameonly
)
def filerevision_highlight(orig, web, fctx):
mt = web.res.headers[b'Content-Type']
# only pygmentize for mimetype containing 'html' so we both match
# 'text/html' and possibly 'application/xhtml+xml' in the future
# so that we don't have to touch the extension when the mimetype
# for a template changes; also hgweb optimizes the case that a
# raw file is sent using rawfile() and doesn't call us, so we
# can't clash with the file's content-type here in case we
# pygmentize a html file
if b'html' in mt:
pygmentize(web, b'fileline', fctx, web.tmpl)
return orig(web, fctx)
def annotate_highlight(orig, web):
mt = web.res.headers[b'Content-Type']
if b'html' in mt:
fctx = webutil.filectx(web.repo, web.req)
pygmentize(web, b'annotateline', fctx, web.tmpl)
return orig(web)
def generate_css(web):
pg_style = web.config(b'web', b'pygments_style', b'colorful')
fmter = highlight.HtmlFormatter(style=pycompat.sysstr(pg_style))
web.res.headers[b'Content-Type'] = b'text/css'
style_defs = fmter.get_style_defs(pycompat.sysstr(b''))
web.res.setbodybytes(
b''.join(
[
b'/* pygments_style = %s */\n\n' % pg_style,
pycompat.bytestr(style_defs),
]
)
)
return web.res.sendresponse()
def extsetup(ui):
# monkeypatch in the new version
extensions.wrapfunction(
webcommands, b'_filerevision', filerevision_highlight
)
extensions.wrapfunction(webcommands, b'annotate', annotate_highlight)
webcommands.highlightcss = generate_css
webcommands.__all__.append(b'highlightcss')