log: --author-date-order

Sometimes people would want to view the commits in parallel
histories in the order of author dates, not committer dates.

Teach "topo-order" sort machinery to do so, using a commit-info slab
to record the author dates of each commit, and prio-queue to sort
them.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/commit.h b/commit.h
index 247e474e44..e43dfd0182 100644
--- a/commit.h
+++ b/commit.h
@@ -142,7 +142,8 @@ void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark);
 
 enum rev_sort_order {
 	REV_SORT_IN_GRAPH_ORDER = 0,
-	REV_SORT_BY_COMMIT_DATE
+	REV_SORT_BY_COMMIT_DATE,
+	REV_SORT_BY_AUTHOR_DATE
 };
 
 /*