- fd = open(git_path("%s", ref), O_RDONLY);
- if (fd < 0)
- return -1;
- ret = -1;
- if (read(fd, buffer, sizeof(buffer)) >= 40)
- ret = get_sha1_hex(buffer, sha1);
- close(fd);
- return ret;
+ /* Both new and old must be commit-ish and new is descendant of
+ * old. Otherwise we require --force.
+ */
+ o = deref_tag(parse_object(old_sha1));
+ if (!o || o->type != commit_type)
+ return 0;
+ old = (struct commit *) o;
+
+ o = deref_tag(parse_object(new_sha1));
+ if (!o || o->type != commit_type)
+ return 0;
+ new = (struct commit *) o;
+
+ if (parse_commit(new) < 0)
+ return 0;
+ list = NULL;
+ commit_list_insert(new, &list);
+ while (list) {
+ new = pop_most_recent_commit(&list, 1);
+ if (new == old)
+ return 1;
+ }
+ return 0;
+}
+
+static struct ref *local_refs, **local_tail;
+static struct ref *remote_refs, **remote_tail;
+
+static int one_local_ref(const char *refname, const unsigned char *sha1)
+{
+ struct ref *ref;
+ int len = strlen(refname) + 1;
+ ref = xcalloc(1, sizeof(*ref) + len);
+ memcpy(ref->new_sha1, sha1, 20);
+ memcpy(ref->name, refname, len);
+ *local_tail = ref;
+ local_tail = &ref->next;
+ return 0;
+}
+
+static void get_local_heads(void)
+{
+ local_tail = &local_refs;
+ for_each_ref(one_local_ref);