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
===================================================================
unknown
acb14030fe0a tip
acb14030fe0a21b60322c440ad2d20cf7685a376 first
tip 1:b9154636be938d3d431e75a7c906504a079bfe07
first 0:acb14030fe0a21b60322c440ad2d20cf7685a376
b9154636be93 tip
M a
b9154636be93+ tip
acb14030fe0a+ first
acb14030fe0a21b60322c440ad2d20cf7685a376+ first
M a
c8edf04160c7 tip
c8edf04160c7+b9154636be93+ tip
M .hgtags