revlog: drop the df argument to `rawdata`

The intend of this argument is better filled by the `revlog.reading` or
`revlog._writing` context. So we drop it to leave rooms for further cleanup and
improvements.

mercurial/filelog.py

@@ -110,8 +110,8 b' class filelog:'
     def revision(self, node):
         return self._revlog.revision(node)
 
-    def rawdata(self, node, _df=None):
-        return self._revlog.rawdata(node, _df=_df)
+    def rawdata(self, node):
+        return self._revlog.rawdata(node)
 
     def emitrevisions(
         self,

mercurial/interfaces/repository.py

@@ -1285,7 +1285,7 b' class imanifeststorage(interfaceutil.Int'
     def revision(node):
         """Obtain fulltext data for a node."""
 
-    def rawdata(node, _df=None):
+    def rawdata(node):
         """Obtain raw data for a node."""
 
     def revdiff(rev1, rev2):

mercurial/manifest.py

@@ -1824,8 +1824,8 b' class manifestrevlog:'
     def revision(self, node):
         return self._revlog.revision(node)
 
-    def rawdata(self, node, _df=None):
-        return self._revlog.rawdata(node, _df=_df)
+    def rawdata(self, node):
+        return self._revlog.rawdata(node)
 
     def revdiff(self, rev1, rev2):
         return self._revlog.revdiff(rev1, rev2)

mercurial/revlog.py

@@ -2099,12 +2099,9 b' class revlog:'
         sidedata = sidedatautil.deserialize_sidedata(segment)
         return sidedata
 
-    def rawdata(self, nodeorrev, _df=None):
-        """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 rawdata(self, nodeorrev):
+        """return an uncompressed raw data of a given node or revision number."""
+        return self._revisiondata(nodeorrev, raw=True)
 
     def hash(self, text, p1, p2):
         """Compute a node hash.