+ if (commit->object.flags & COMMON) {
+ /* do not send "have", and ignore ancestors */
+ commit = NULL;
+ mark = COMMON | SEEN;
+ } else if (commit->object.flags & COMMON_REF)
+ /* send "have", and ignore ancestors */
+ mark = COMMON | SEEN;
+ else
+ /* send "have", also for its ancestors */
+ mark = SEEN;
+
+ while (parents) {
+ if (!(parents->item->object.flags & SEEN))
+ rev_list_push(parents->item, mark);
+ if (mark & COMMON)
+ mark_common(parents->item, 1, 0);
+ parents = parents->next;
+ }
+
+ rev_list = rev_list->next;
+ }
+
+ return commit->object.sha1;
+}
+
+static int find_common(int fd[2], unsigned char *result_sha1,
+ struct ref *refs)
+{
+ int fetching;
+ int count = 0, flushes = 0, retval;
+ const unsigned char *sha1;
+
+ for_each_ref(rev_list_insert_ref);
+
+ fetching = 0;
+ for ( ; refs ; refs = refs->next) {
+ unsigned char *remote = refs->old_sha1;
+ struct object *o;
+
+ /*
+ * If that object is complete (i.e. it is an ancestor of a
+ * local ref), we tell them we have it but do not have to
+ * tell them about its ancestors, which they already know
+ * about.
+ *
+ * We use lookup_object here because we are only
+ * interested in the case we *know* the object is
+ * reachable and we have already scanned it.
+ */
+ if (((o = lookup_object(remote)) != NULL) &&
+ (o->flags & COMPLETE)) {
+ continue;
+ }
+
+ packet_write(fd[1], "want %s%s\n", sha1_to_hex(remote),
+ multi_ack ? " multi_ack" : "");
+ fetching++;
+ }