--- a/mercurial/changegroup.py Tue Apr 01 14:13:34 2014 -0700
+++ b/mercurial/changegroup.py Tue Apr 01 14:25:03 2014 -0700
@@ -6,9 +6,10 @@
# GNU General Public License version 2 or any later version.
from i18n import _
-from node import nullrev, hex
+from node import nullrev, nullid, hex
import mdiff, util, dagutil
import struct, os, bz2, zlib, tempfile
+import discovery
_BUNDLE10_DELTA_HEADER = "20s20s20s20s"
@@ -453,3 +454,29 @@
_changegroupinfo(repo, csets, source)
gengroup = bundler.generate(commonrevs, csets, fastpathlinkrev, source)
return unbundle10(util.chunkbuffer(gengroup), 'UN')
+
+def changegroupsubset(repo, roots, heads, source):
+ """Compute a changegroup consisting of all the nodes that are
+ descendants of any of the roots and ancestors of any of the heads.
+ Return a chunkbuffer object whose read() method will return
+ successive changegroup chunks.
+
+ It is fairly complex as determining which filenodes and which
+ manifest nodes need to be included for the changeset to be complete
+ is non-trivial.
+
+ Another wrinkle is doing the reverse, figuring out which changeset in
+ the changegroup a particular filenode or manifestnode belongs to.
+ """
+ cl = repo.changelog
+ if not roots:
+ roots = [nullid]
+ # TODO: remove call to nodesbetween.
+ csets, roots, heads = cl.nodesbetween(roots, heads)
+ discbases = []
+ for n in roots:
+ discbases.extend([p for p in cl.parents(n) if p != nullid])
+ outgoing = discovery.outgoing(cl, discbases, heads)
+ bundler = bundle10(repo)
+ return getsubset(repo, outgoing, bundler, source)
+