Optimize dirstate walking
This generally cuts the time for hg status/diff in half, from 2s down to 1s.
The main parts I'm trying to optimize are:
1) os.walk stats every file. dirstate.changes then stats every file again.
2) os.walk yields every file and subdir to dirstate.traverse who yields every
file and everything in the dirstate map. dirstate.walk then
filters this mass and yields every file to the caller. There should be
fewer steps in here, and fewer duplicate strings yielded.
3) dirstate.walk runs util.unique on the results from dirstate.traverse,
even though it is also passing things through dirstate.seen to look for
duplicates.
I've turned os.walk into something hg specific that takes all the dirstate
ignore and matching rules into account. The new function also takes an
function arg (statmatch()) the caller supplies to help filter out
files it doesn't care about. dirstate.changes uses this to update state
for each file, avoiding the second stat call.
dirstate.walk is changed to turn the match function it is passed into
a statmatch function. The only real difference is that a statmatch
function takes the stat data as a second parameter. It now calls
dirstate.walkhelper, who requires a statmatch function to be passed.
This fails test-walk, but right now I think this is from a sorting error
fixed by this patch.
Index: crew/mercurial/dirstate.py
===================================================================
# Copyright (C) 2005 by Intevation GmbH
# Author(s):
# Thomas Arendsen Hein <thomas@intevation.de>
#
# This program is free software under the GNU GPL (>=v2)
# Read the file COPYING coming with the software for details.
"""
Mercurial version
"""
import os
import os.path
import re
import time
import util
unknown_version = 'unknown'
remembered_version = False
def get_version():
"""Return version information if available."""
try:
from mercurial.__version__ import version
except ImportError:
version = unknown_version
return version
def write_version(version):
"""Overwrite version file."""
filename = os.path.join(os.path.dirname(__file__), '__version__.py')
f = open(filename, 'w')
f.write("# This file is auto-generated.\n")
f.write("version = %r\n" % version)
f.close()
def remember_version(version=None):
"""Store version information."""
global remembered_version
if not version and os.path.isdir(".hg"):
f = os.popen("hg identify 2> %s" % util.nulldev) # use real hg installation
ident = f.read()[:-1]
if not f.close() and ident:
ids = ident.split(' ', 1)
version = ids.pop(0)
if version[-1] == '+':
version = version[:-1]
modified = True
else:
modified = False
if version.isalnum() and ids:
for tag in ids[0].split('/'):
# is a tag is suitable as a version number?
if re.match(r'^(\d+\.)+[\w.-]+$', tag):
version = tag
break
if modified:
version += time.strftime('+%Y%m%d')
if version:
remembered_version = True
write_version(version)
def forget_version():
"""Remove version information."""
if remembered_version:
write_version(unknown_version)