+#define COMPLETE (1U << 0)
+#define COMMON (1U << 1)
+#define COMMON_REF (1U << 2)
+#define SEEN (1U << 3)
+#define POPPED (1U << 4)
+
+static struct commit_list *rev_list = NULL;
+static int non_common_revs = 0, multi_ack = 0;
+
+static void rev_list_push(struct commit *commit, int mark)
+{
+ if (!(commit->object.flags & mark)) {
+ commit->object.flags |= mark;
+
+ if (!(commit->object.parsed))
+ parse_commit(commit);
+
+ insert_by_date(commit, &rev_list);
+
+ if (!(commit->object.flags & COMMON))
+ non_common_revs++;
+ }
+}
+
+static int rev_list_insert_ref(const char *path, const unsigned char *sha1)
+{
+ struct object *o = deref_tag(parse_object(sha1), path, 0);
+
+ if (o && o->type == commit_type)
+ rev_list_push((struct commit *)o, SEEN);
+
+ return 0;
+}
+
+/*
+ This function marks a rev and its ancestors as common.
+ In some cases, it is desirable to mark only the ancestors (for example
+ when only the server does not yet know that they are common).
+*/
+
+static void mark_common(struct commit *commit,
+ int ancestors_only, int dont_parse)