Mercurial > hg
view mercurial/diffhelper.py @ 41247:a89b20a49c13
rust-cpython: using MissingAncestors from Python code
As precedently done with LazyAncestors on cpython.rs, we test for the
presence of the 'rustext' module.
incrementalmissingrevs() has two callers within the Mercurial core:
`setdiscovery.partialdiscovery` and the `only()` revset.
This move shows a significant discovery performance improvement
in cases where the baseline is slow: using perfdiscovery on the PyPy
repos, prepared with `contrib/discovery-helper <repo> 50 100`, we
get averaged medians of 403ms with the Rust version vs 742ms without
(about 45% better).
But there are still indications that performance can be worse in cases
the baseline is fast, possibly due to the conversion from Python to
Rust and back becoming the bottleneck. We could measure this on
mozilla-central in cases were the delta is just a few changesets.
This requires confirmation, but if that's the reason, then an
upcoming `partialdiscovery` fully in Rust should solve the problem.
Differential Revision: https://phab.mercurial-scm.org/D5551
author | Georges Racinet <georges.racinet@octobus.net> |
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date | Fri, 30 Nov 2018 14:35:57 +0100 |
parents | e7aa113b14f7 |
children | 57875cf423c9 |
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# diffhelper.py - helper routines for patch # # Copyright 2009 Matt Mackall <mpm@selenic.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. from __future__ import absolute_import from .i18n import _ from . import ( error, pycompat, ) def addlines(fp, hunk, lena, lenb, a, b): """Read lines from fp into the hunk The hunk is parsed into two arrays, a and b. a gets the old state of the text, b gets the new state. The control char from the hunk is saved when inserting into a, but not b (for performance while deleting files.) """ while True: todoa = lena - len(a) todob = lenb - len(b) num = max(todoa, todob) if num == 0: break for i in pycompat.xrange(num): s = fp.readline() if not s: raise error.ParseError(_('incomplete hunk')) if s == "\\ No newline at end of file\n": fixnewline(hunk, a, b) continue if s == '\n' or s == '\r\n': # Some patches may be missing the control char # on empty lines. Supply a leading space. s = ' ' + s hunk.append(s) if s.startswith('+'): b.append(s[1:]) elif s.startswith('-'): a.append(s) else: b.append(s[1:]) a.append(s) def fixnewline(hunk, a, b): """Fix up the last lines of a and b when the patch has no newline at EOF""" l = hunk[-1] # tolerate CRLF in last line if l.endswith('\r\n'): hline = l[:-2] else: hline = l[:-1] if hline.startswith((' ', '+')): b[-1] = hline[1:] if hline.startswith((' ', '-')): a[-1] = hline hunk[-1] = hline def testhunk(a, b, bstart): """Compare the lines in a with the lines in b a is assumed to have a control char at the start of each line, this char is ignored in the compare. """ alen = len(a) blen = len(b) if alen > blen - bstart or bstart < 0: return False for i in pycompat.xrange(alen): if a[i][1:] != b[i + bstart]: return False return True