[PATCH 3 of 4 RFC] revlog: support for compressing delta groups reusing zlib stream

[Wagner Bruna]

# HG changeset patch
# User Wagner Bruna <wbruna at softwareexpress.com.br>
# Date 1265662372 7200
# Node ID 7d83e89bc4d623bc7fa6fe362d7f93e7d355df60
# Parent  a4e7b83470e475f4cc37d1f9a2fe1187d0a86fcf
revlog: support for compressing delta groups reusing zlib stream

diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -1272,6 +1272,7 @@
         try:
             # loop through our set of deltas
             chain = None
+            comprobj = None
             for chunk in revs:
                 node, p1, p2, cs = struct.unpack("20s20s20s20s", chunk[:80])
                 link = linkmapper(cs)
@@ -1299,7 +1300,7 @@
                 # current size.
 
                 if chain == prev:
-                    cdelta = compress(delta)
+                    cdelta = compress(delta, comprobj)
                     cdeltalen = len(cdelta[0]) + len(cdelta[1])
                     textlen = mdiff.patchedsize(textlen, delta)
 
@@ -1317,6 +1318,8 @@
                     del delta
                     chk = self._addrevision(text, transaction, link, p1, p2, None,
                                             ifh, dfh)
+                    comprobj = zlib.compressobj()
+                    compress(text, comprobj)
                     if not dfh and not self._inline:
                         # addrevision switched from inline to conventional
                         # reopen the index