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 ===================================================================

#!/usr/bin/env python
import sys, os
from mercurial import hg

f = sys.argv[1]

r1 = hg.revlog(open, f + ".i", f + ".d")
r2 = hg.revlog(open, f + ".i2", f + ".d2")

tr = hg.transaction(open, "journal")

for i in xrange(r1.count()):
    n = r1.node(i)
    p1, p2 = r1.parents(n)
    l = r1.linkrev(n)
    t = r1.revision(n)
    n2 = r2.addrevision(t, tr, l, p1, p2)
tr.close()

os.rename(f + ".i", f + ".i.old")
os.rename(f + ".d", f + ".d.old")
os.rename(f + ".i2", f + ".i")
os.rename(f + ".d2", f + ".d")