diff --git a/mercurial/store.py b/mercurial/store.py
--- a/mercurial/store.py
+++ b/mercurial/store.py
@@ -24,6 +24,21 @@
 
 parsers = policy.importmod(r'parsers')
 
+def _gettrackedpath(path):
+    """parses a fncahe entry and returns the path which that
+    entry is tracking.
+
+    If None is returned, it means it does not track any path.
+    """
+    path = decodefilename(path)
+    if path.startswith('data/'):
+        return path[5:-2]
+    elif path.startswith('dh/'):
+        return path[3:-2]
+    elif path.startswith('meta/'):
+        return path[5:-2]
+    return None
+
 # This avoids a collision between a file named foo and a dir named
 # foo.i or foo.d
 def _encodedir(path):