+ if (obj->refs) {
+ const struct object_refs *refs = obj->refs;
+ unsigned i;
+ for (i = 0; i < refs->count; i++)
+ mark_reachable(refs->ref[i], mask);
+ }
+}
+
+struct object *lookup_object_type(const unsigned char *sha1, const char *type)
+{
+ if (!type) {
+ return lookup_unknown_object(sha1);
+ } else if (!strcmp(type, blob_type)) {
+ return &lookup_blob(sha1)->object;
+ } else if (!strcmp(type, tree_type)) {
+ return &lookup_tree(sha1)->object;
+ } else if (!strcmp(type, commit_type)) {
+ return &lookup_commit(sha1)->object;
+ } else if (!strcmp(type, tag_type)) {
+ return &lookup_tag(sha1)->object;
+ } else {
+ error("Unknown type %s", type);
+ return NULL;
+ }
+}
+
+union any_object {
+ struct object object;
+ struct commit commit;
+ struct tree tree;
+ struct blob blob;
+ struct tag tag;
+};
+
+struct object *lookup_unknown_object(const unsigned char *sha1)
+{
+ struct object *obj = lookup_object(sha1);
+ if (!obj) {
+ union any_object *ret = xmalloc(sizeof(*ret));
+ memset(ret, 0, sizeof(*ret));
+ created_object(sha1, &ret->object);
+ ret->object.type = NULL;
+ return &ret->object;