vfs: allow to pass more argument to audit

We want to be able to do more precise check when auditing a path depending of
the intend of the file access (eg read versus write). So we now pass the 'mode'
value to 'audit' and update the audit function to accept them.

This will be put to use in the next changeset.

mercurial/pathutil.py

@@ -46,7 +46,7 b' class pathauditor(object):'
         else:
             self.normcase = lambda x: x
 
-    def __call__(self, path):
+    def __call__(self, path, mode=None):
         '''Check the relative path.
         path may contain a pattern (e.g. foodir/**.txt)'''
 

mercurial/vfs.py

@@ -306,7 +306,7 b' class vfs(abstractvfs):'
         if audit:
             self.audit = pathutil.pathauditor(self.base)
         else:
-            self.audit = util.always
+            self.audit = (lambda path, mode=None: True)
         self.createmode = None
         self._trustnlink = None
 
@@ -360,7 +360,7 b' class vfs(abstractvfs):'
                 r = util.checkosfilename(path)
                 if r:
                     raise error.Abort("%s: %r" % (r, path))
-            self.audit(path)
+            self.audit(path, mode=mode)
         f = self.join(path)
 
         if not text and "b" not in mode: