+ if (get_sha1_1(name, sp - name - 2, outer))
+ return -1;
+
+ o = parse_object(outer);
+ if (!o)
+ return -1;
+ if (!type_string) {
+ o = deref_tag(o, name, sp - name - 2);
+ if (!o || (!o->parsed && !parse_object(o->sha1)))
+ return -1;
+ memcpy(sha1, o->sha1, 20);
+ }
+ else {
+ /* At this point, the syntax look correct, so
+ * if we do not get the needed object, we should
+ * barf.
+ */
+
+ while (1) {
+ if (!o || (!o->parsed && !parse_object(o->sha1)))
+ return -1;
+ if (o->type == type_string) {
+ memcpy(sha1, o->sha1, 20);
+ return 0;
+ }
+ if (o->type == tag_type)
+ o = ((struct tag*) o)->tagged;
+ else if (o->type == commit_type)
+ o = &(((struct commit *) o)->tree->object);
+ else
+ return error("%.*s: expected %s type, but the object dereferences to %s type",
+ len, name, type_string,
+ o->type);
+ if (!o->parsed)
+ parse_object(o->sha1);
+ }
+ }
+ return 0;
+}
+
+static int get_sha1_1(const char *name, int len, unsigned char *sha1)
+{
+ int ret, has_suffix;
+ const char *cp;
+
+ /* "name~3" is "name^^^",
+ * "name~" and "name~0" are name -- not "name^0"!
+ * "name^" is not "name^0"; it is "name^1".
+ */
+ has_suffix = 0;
+ for (cp = name + len - 1; name <= cp; cp--) {
+ int ch = *cp;
+ if ('0' <= ch && ch <= '9')
+ continue;
+ if (ch == '~' || ch == '^')
+ has_suffix = ch;
+ break;
+ }
+
+ if (has_suffix) {
+ int num = 0;
+ int len1 = cp - name;
+ cp++;
+ while (cp < name + len)
+ num = num * 10 + *cp++ - '0';
+ if (has_suffix == '^') {
+ if (!num && len1 == len - 1)
+ num = 1;
+ return get_parent(name, len1, sha1, num);
+ }
+ /* else if (has_suffix == '~') -- goes without saying */
+ return get_nth_ancestor(name, len1, sha1, num);