match: use re2 in readpatternfile if possible
This has a small, but measurable, effect on performance if a pattern
file is very large. In an artificial test with 200,000 lines of
pattern data, using re2 reduced read time by 200 milliseconds.
--- a/mercurial/match.py Thu Dec 10 21:32:19 2015 -0800
+++ b/mercurial/match.py Thu Dec 10 21:33:55 2015 -0800
@@ -654,9 +654,11 @@
if "#" in line:
global _commentre
if not _commentre:
- _commentre = re.compile(r'((^|[^\\])(\\\\)*)#.*')
+ _commentre = util.re.compile(r'((?:^|[^\\])(?:\\\\)*)#.*')
# remove comments prefixed by an even number of escapes
- line = _commentre.sub(r'\1', line)
+ m = _commentre.search(line)
+ if m:
+ line = line[:m.end(1)]
# fixup properly escaped comments that survived the above
line = line.replace("\\#", "#")
line = line.rstrip()