dirstate walking optimizations The repo walking code introduces a number of calls to dirstate.map.copy(), significantly slowing down the walk on large trees. When a list of files is passed to the walking code, we should only look at map entries relevant to the file list passed in. dirstate.filterfiles() is added to return a subset of the dirstate map. The subset includes in files passed in, and if one of the files requested is actually a directory, it includes any files inside that directory tree. This brings the time for hg diff Makefile down from 1.7s to .3s on a linux kernel repo. Also, the diff command was unconditionally calling makewalk, leading to an extra pass through repo.changes. This patch avoids the call to makewalk when commands.diff isn't given a list of patterns, cutting the time for hg diff (with no args) in half. Index: mine/mercurial/hg.py ===================================================================

+ hg init
+ hg id
unknown
+ hg add a
+ hg commit -m test -d 0 0
+ hg co
+ hg identify
acb14030fe0a tip
+ hg -q tip
acb14030fe0a21b60322c440ad2d20cf7685a376 first
+ hg add .hgtags
+ hg commit -m add tags -d 0 0
+ hg tags
tip                                1:b53d0e1f3043ecbccf1b9ad2cea562c1b50462b2
first                              0:acb14030fe0a21b60322c440ad2d20cf7685a376
hg -q tip                          ?:?
+ hg identify
b53d0e1f3043 tip
+ hg status
M a
+ hg identify
b53d0e1f3043+ tip
+ hg co first
+ hg id
acb14030fe0a+ first
+ hg -v id
acb14030fe0a21b60322c440ad2d20cf7685a376+ first
+ hg status
M a
+ hg add b
+ hg commit -m branch -d 0 0
+ hg id
c8edf04160c7 tip
+ hg co -m 1
+ hg id
c8edf04160c7+b53d0e1f3043+ tip
+ hg status
M .hgtags
M a