+ if (!we_knew_they_have) {
+ add_object_array(o, NULL, &have_obj);
+ return 1;
+ }
+ return 0;
+}
+
+static int reachable(struct commit *want)
+{
+ struct commit_list *work = NULL;
+
+ insert_by_date(want, &work);
+ while (work) {
+ struct commit_list *list = work->next;
+ struct commit *commit = work->item;
+ free(work);
+ work = list;
+
+ if (commit->object.flags & THEY_HAVE) {
+ want->object.flags |= COMMON_KNOWN;
+ break;
+ }
+ if (!commit->object.parsed)
+ parse_object(commit->object.sha1);
+ if (commit->object.flags & REACHABLE)
+ continue;
+ commit->object.flags |= REACHABLE;
+ if (commit->date < oldest_have)
+ continue;
+ for (list = commit->parents; list; list = list->next) {
+ struct commit *parent = list->item;
+ if (!(parent->object.flags & REACHABLE))
+ insert_by_date(parent, &work);
+ }
+ }
+ want->object.flags |= REACHABLE;
+ clear_commit_marks(want, REACHABLE);
+ free_commit_list(work);
+ return (want->object.flags & COMMON_KNOWN);
+}
+
+static int ok_to_give_up(void)
+{
+ int i;
+
+ if (!have_obj.nr)
+ return 0;
+
+ for (i = 0; i < want_obj.nr; i++) {
+ struct object *want = want_obj.objects[i].item;
+
+ if (want->flags & COMMON_KNOWN)
+ continue;
+ want = deref_tag(want, "a want line", 0);
+ if (!want || want->type != OBJ_COMMIT) {
+ /* no way to tell if this is reachable by
+ * looking at the ancestry chain alone, so
+ * leave a note to ourselves not to worry about
+ * this object anymore.
+ */
+ want_obj.objects[i].item->flags |= COMMON_KNOWN;
+ continue;
+ }
+ if (!reachable((struct commit *)want))
+ return 0;
+ }