diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -1720,6 +1720,13 @@ class revlog(object):
 
         return text
 
+    def rawdata(self, nodeorrev, _df=None, raw=False):
+        """return an uncompressed raw data of a given node or revision number.
+
+        _df - an existing file handle to read from. (internal-only)
+        """
+        return self._revisiondata(nodeorrev, _df, raw=True)
+
     def hash(self, text, p1, p2):
         """Compute a node hash.