diff -r 52d34d5415c9 -r 977a0b9af5ac mercurial/dirstate.py
--- a/mercurial/dirstate.py	Sat Aug 02 09:45:21 2014 +0100
+++ b/mercurial/dirstate.py	Fri Aug 01 22:05:16 2014 -0700
@@ -873,3 +873,21 @@
 
         return (lookup, modified, added, removed, deleted, unknown, ignored,
                 clean)
+
+    def matches(self, match):
+        '''
+        return files in the dirstate (in whatever state) filtered by match
+        '''
+        dmap = self._map
+        if match.always():
+            return dmap.keys()
+        files = match.files()
+        if match.matchfn == match.exact:
+            # fast path -- filter the other way around, since typically files is
+            # much smaller than dmap
+            return [f for f in files if f in dmap]
+        if not match.anypats() and util.all(fn in dmap for fn in files):
+            # fast path -- all the values are known to be files, so just return
+            # that
+            return list(files)
+        return [f for f in dmap if match(f)]