largefiles: split the creation of a normal matcher out of its install method

Refactoring addremove to support subrepos will need the ability to keep passing
the same matcher and narrowing it, instead of monkey patching scmutil's matcher.

hgext/largefiles/overrides.py

@@ -22,11 +22,7 import basestore
 
 # -- Utility functions: commonly/repeatedly needed functionality ---------------
 
-def installnormalfilesmatchfn(manifest):
-    '''installmatchfn with a matchfn that ignores all largefiles'''
-    def overridematch(ctx, pats=[], opts={}, globbed=False,
-            default='relpath'):
-        match = oldmatch(ctx, pats, opts, globbed, default)
+def composenormalfilematcher(match, manifest):
         m = copy.copy(match)
         notlfile = lambda f: not (lfutil.isstandin(f) or lfutil.standin(f) in
                 manifest)
@@ -36,6 +32,13 def installnormalfilesmatchfn(manifest):
         origmatchfn = m.matchfn
         m.matchfn = lambda f: notlfile(f) and origmatchfn(f)
         return m
+
+def installnormalfilesmatchfn(manifest):
+    '''installmatchfn with a matchfn that ignores all largefiles'''
+    def overridematch(ctx, pats=[], opts={}, globbed=False,
+            default='relpath'):
+        match = oldmatch(ctx, pats, opts, globbed, default)
+        return composenormalfilematcher(match, manifest)
     oldmatch = installmatchfn(overridematch)
 
 def installmatchfn(f):