context: add a match builder method

This is groundwork for matching against filesets in contexts

mercurial/context.py

@@ -8,6 +8,7 b''
 from node import nullid, nullrev, short, hex
 from i18n import _
 import ancestor, bdiff, error, util, scmutil, subrepo, patch, encoding
+import match as matchmod
 import os, errno, stat
 
 propertycache = util.propertycache
@@ -208,6 +209,11 b' class changectx(object):'
     def sub(self, path):
         return subrepo.subrepo(self, path)
 
+    def match(self, pats=[], include=None, exclude=None, default='glob'):
+        r = self._repo
+        return matchmod.match(r.root, r.getcwd(), pats,
+                              include, exclude, default, auditor=r.auditor)
+
     def diff(self, ctx2=None, match=None, **opts):
         """Returns a diff generator for the given contexts and matcher"""
         if ctx2 is None:

mercurial/scmutil.py

@@ -563,9 +563,8 b' def match(repo, pats=[], opts={}, globbe'
         pats = []
     if not globbed and default == 'relpath':
         pats = expandpats(pats or [])
-    m = matchmod.match(repo.root, repo.getcwd(), pats,
-                       opts.get('include'), opts.get('exclude'), default,
-                       auditor=repo.auditor)
+    m = repo[None].match(pats, opts.get('include'), opts.get('exclude'),
+                         default)
     def badfn(f, msg):
         repo.ui.warn("%s: %s\n" % (m.rel(f), msg))
     m.bad = badfn