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

#!/bin/sh

hg clone http://localhost:20059/ copy
echo $?
ls copy

cat > dumb.py <<EOF
import BaseHTTPServer, SimpleHTTPServer, signal

def run(server_class=BaseHTTPServer.HTTPServer,
        handler_class=SimpleHTTPServer.SimpleHTTPRequestHandler):
    server_address = ('localhost', 20059)
    httpd = server_class(server_address, handler_class)
    httpd.serve_forever()

signal.signal(signal.SIGTERM, lambda x: sys.exit(0))
run()
EOF

python dumb.py 2>/dev/null &

hg clone http://localhost:20059/foo copy2
echo $?

kill $!