match: add isexact() method to hide internals

Comparing a function reference seems bad.

mercurial/dirstate.py

@@ -611,7 +611,7 b' class dirstate(object):'
         dirsnotfound = []
         notfoundadd = dirsnotfound.append
 
-        if match.matchfn != match.exact and self._checkcase:
+        if not match.isexact() and self._checkcase:
             normalize = self._normalize
         else:
             normalize = None
@@ -711,7 +711,7 b' class dirstate(object):'
         join = self._join
 
         exact = skipstep3 = False
-        if matchfn == match.exact: # match.exact
+        if match.isexact(): # match.exact
             exact = True
             dirignore = util.always # skip step 2
         elif match.files() and not match.anypats(): # match.match, no patterns
@@ -912,7 +912,7 b' class dirstate(object):'
         if match.always():
             return dmap.keys()
         files = match.files()
-        if match.matchfn == match.exact:
+        if match.isexact():
             # 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]

mercurial/manifest.py

@@ -164,7 +164,7 b' class manifestdict(object):'
             return self.copy()
 
         files = match.files()
-        if (len(files) < 100 and (match.matchfn == match.exact or
+        if (len(files) < 100 and (match.isexact() or
             (not match.anypats() and util.all(fn in self for fn in files)))):
             return self.intersectfiles(files)
 
@@ -519,7 +519,7 b' class treemanifest(object):'
             return self.copy()
 
         files = match.files()
-        if (match.matchfn == match.exact or
+        if (match.isexact() or
             (not match.anypats() and util.all(fn in self for fn in files))):
             return self.intersectfiles(files)
 

mercurial/match.py

@@ -171,6 +171,9 b' class match(object):'
         - optimization might be possible and necessary.'''
         return self._always
 
+    def isexact(self):
+        return self.matchfn == self.exact
+
 def exact(root, cwd, files):
     return match(root, cwd, files, exact=True)