list-objects: add "void *data" parameter to show functions

The goal of this patch is to get rid of the "static struct rev_info
revs" static variable in "builtin-rev-list.c".

To do that, we need to pass the revs to the "show_commit" function
in "builtin-rev-list.c" and this in turn means that the
"traverse_commit_list" function in "list-objects.c" must be passed
functions pointers to functions with 2 parameters instead of one.

So we have to change all the callers and all the functions passed
to "traverse_commit_list".

Anyway this makes the code more clean and more generic, so it
should be a good thing in the long run.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/upload-pack.c b/upload-pack.c
index a49d872..495c99f 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -66,7 +66,7 @@
 }
 
 static FILE *pack_pipe = NULL;
-static void show_commit(struct commit *commit)
+static void show_commit(struct commit *commit, void *data)
 {
 	if (commit->object.flags & BOUNDARY)
 		fputc('-', pack_pipe);
@@ -78,7 +78,7 @@
 	commit->buffer = NULL;
 }
 
-static void show_object(struct object_array_entry *p)
+static void show_object(struct object_array_entry *p, void *data)
 {
 	/* An object with name "foo\n0000000..." can be used to
 	 * confuse downstream git-pack-objects very badly.
@@ -134,7 +134,7 @@
 	if (prepare_revision_walk(&revs))
 		die("revision walk setup failed");
 	mark_edges_uninteresting(revs.commits, &revs, show_edge);
-	traverse_commit_list(&revs, show_commit, show_object);
+	traverse_commit_list(&revs, show_commit, show_object, NULL);
 	fflush(pack_pipe);
 	fclose(pack_pipe);
 	return 0;