[PATCH 1 of 3] revlog: split deltaparent into fast and slow versions

Sune Foldager cryo at cyanite.org
Wed May 4 16:42:07 CDT 2011


# HG changeset patch
# User Sune Foldager <cryo at cyanite.org>
# Date 1304544513 -7200
# Node ID be4a52cc2fe9b982dbec4a44809481e41b9cbe29
# Parent  4ab6e2d597cca476a3aab865620ec946dd307972
revlog: split deltaparent into fast and slow versions

The slow version always returns the correct deltaparent, returning -1 for base
revisions. The fast version returns the deltaparent for non-base revisions and
an incorrect revision for base revisions.

diff --git a/mercurial/manifest.py b/mercurial/manifest.py
--- a/mercurial/manifest.py
+++ b/mercurial/manifest.py
@@ -36,12 +36,12 @@
 
     def readdelta(self, node):
         r = self.rev(node)
-        return self.parse(mdiff.patchtext(self.revdiff(self.deltaparent(r), r)))
+        return self.parse(mdiff.patchtext(self.revdiff(self._deltaparent(r), r)))
 
     def readfast(self, node):
         '''use the faster of readdelta or read'''
         r = self.rev(node)
-        if self.deltaparent(r) in self.parentrevs(r):
+        if self._deltaparent(r) in self.parentrevs(r):
             return self.readdelta(node)
         return self.read(node)
 
diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -833,16 +833,22 @@
     def _chunkclear(self):
         self._chunkcache = (0, '')
 
-    def deltaparent(self, rev):
-        """return previous revision or parentrev according to flags"""
+    def _deltaparent(self, rev):
         if self.flags(rev) & REVIDX_PARENTDELTA:
             return self.parentrevs(rev)[0]
         else:
             return rev - 1
 
+    def deltaparent(self, rev):
+        """return deltaparent of the given revision"""
+        if self.index[rev][3] == rev:
+            return nullrev
+        else:
+            return self._deltaparent(rev)
+
     def revdiff(self, rev1, rev2):
         """return or calculate a delta between two revisions"""
-        if self.base(rev2) != rev2 and self.deltaparent(rev2) == rev1:
+        if rev1 != nullrev and self.deltaparent(rev2) == rev1:
             return self._chunk(rev2)
 
         return mdiff.textdiff(self.revision(self.node(rev1)),


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