commit: add for_each_mergetag()

In the same way as there is for_each_ref() to iterate on refs,
for_each_mergetag() allows the caller to iterate on the mergetags of
a given commit.  Use it to rewrite show_mergetag() used in "git log".

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/commit.h b/commit.h
index 2e1492a..b695aa4 100644
--- a/commit.h
+++ b/commit.h
@@ -312,6 +312,11 @@ extern struct commit_extra_header *read_commit_extra_headers(struct commit *, co
 
 extern void free_commit_extra_headers(struct commit_extra_header *extra);
 
+typedef void (*each_mergetag_fn)(struct commit *commit, struct commit_extra_header *extra,
+				 void *cb_data);
+
+extern void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data);
+
 struct merge_remote_desc {
 	struct object *obj; /* the named object, could be a tag */
 	const char *name;