extensions: move wrapfilecache function from fsmonitor

It makes more sense to put this in core, so other extensions can
trivially get access to it without having to rely on importing
fsmonitor.

hgext/fsmonitor/__init__.py

@@ -561,7 +561,8 b' def wrapdirstate(orig, self):'
     return ds
 
 def extsetup(ui):
-    wrapfilecache(localrepo.localrepository, 'dirstate', wrapdirstate)
+    extensions.wrapfilecache(
+        localrepo.localrepository, 'dirstate', wrapdirstate)
     if pycompat.sysplatform == 'darwin':
         # An assist for avoiding the dangling-symlink fsevents bug
         extensions.wrapfunction(os, 'symlink', wrapsymlink)
@@ -709,21 +710,3 b' def reposetup(ui, repo):'
                 return overridestatus(orig, self, *args, **kwargs)
 
         repo.__class__ = fsmonitorrepo
-
-def wrapfilecache(cls, propname, wrapper):
-    """Wraps a filecache property. These can't be wrapped using the normal
-    wrapfunction. This should eventually go into upstream Mercurial.
-    """
-    assert callable(wrapper)
-    for currcls in cls.__mro__:
-        if propname in currcls.__dict__:
-            origfn = currcls.__dict__[propname].func
-            assert callable(origfn)
-            def wrap(*args, **kwargs):
-                return wrapper(origfn, *args, **kwargs)
-            currcls.__dict__[propname].func = wrap
-            break
-
-    if currcls is object:
-        raise AttributeError(
-            _("type '%s' has no property '%s'") % (cls, propname))

mercurial/extensions.py

@@ -308,6 +308,25 b' def wrapcommand(table, command, wrapper,'
     table[key] = tuple(newentry)
     return entry
 
+def wrapfilecache(cls, propname, wrapper):
+    """Wraps a filecache property.
+
+    These can't be wrapped using the normal wrapfunction.
+    """
+    assert callable(wrapper)
+    for currcls in cls.__mro__:
+        if propname in currcls.__dict__:
+            origfn = currcls.__dict__[propname].func
+            assert callable(origfn)
+            def wrap(*args, **kwargs):
+                return wrapper(origfn, *args, **kwargs)
+            currcls.__dict__[propname].func = wrap
+            break
+
+    if currcls is object:
+        raise AttributeError(
+            _("type '%s' has no property '%s'") % (cls, propname))
+
 def wrapfunction(container, funcname, wrapper):
     '''Wrap the function named funcname in container