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

--- a/mercurial/commands.py	Tue Aug 09 09:36:34 2005 -0800
+++ b/mercurial/commands.py	Fri Aug 12 09:57:56 2005 -0800
@@ -634,9 +634,11 @@
         raise Abort("too many revisions to diff")
 
     files = []
-    roots, match, results = makewalk(repo, pats, opts)
-    for src, abs, rel in results:
-        files.append(abs)
+    match = util.always
+    if pats:
+        roots, match, results = makewalk(repo, pats, opts)
+        for src, abs, rel in results:
+            files.append(abs)
     dodiff(sys.stdout, ui, repo, files, *revs, **{'match': match})
 
 def doexport(ui, repo, changeset, seqno, total, revwidth, opts):