[PATCH] Parse tags for absent objects

Handle parsing a tag for a non-present object. This adds a function to lookup
an object with lookup_* for * in a string, so that it can get the right storage
based on the "type" line in the tag.

Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

object.c

@@ -98,6 +98,22 @@ void mark_reachable(struct object *obj, unsigned int mask)
 	}
 }
 
+struct object *lookup_object_type(const unsigned char *sha1, const char *type)
+{
+	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;
+	}
+}
+
 struct object *parse_object(const unsigned char *sha1)
 {
 	unsigned long mapsize;

object.h

@@ -21,8 +21,12 @@ struct object {
 extern int nr_objs;
 extern struct object **objs;
 
+/** Internal only **/
 struct object *lookup_object(const unsigned char *sha1);
 
+/** Returns the object, having looked it up as being the given type. **/
+struct object *lookup_object_type(const unsigned char *sha1, const char *type);
+
 void created_object(const unsigned char *sha1, struct object *obj);
 
 /** Returns the object, having parsed it to find out what it is. **/

tag.c

@@ -28,6 +28,7 @@ int parse_tag_buffer(struct tag *item, void *data, unsigned long size)
 	int typelen, taglen;
 	unsigned char object[20];
 	const char *type_line, *tag_line, *sig_line;
+	char type[20];
 
         if (item->object.parsed)
                 return 0;
@@ -38,10 +39,6 @@ int parse_tag_buffer(struct tag *item, void *data, unsigned long size)
 	if (memcmp("object ", data, 7) || get_sha1_hex(data + 7, object))
 		return -1;
 
-	item->tagged = parse_object(object);
-	if (item->tagged)
-		add_ref(&item->object, item->tagged);
-
 	type_line = data + 48;
 	if (memcmp("\ntype ", type_line-1, 6))
 		return -1;
@@ -58,11 +55,17 @@ int parse_tag_buffer(struct tag *item, void *data, unsigned long size)
 	typelen = tag_line - type_line - strlen("type \n");
 	if (typelen >= 20)
 		return -1;
+	memcpy(type, type_line + 5, typelen);
+	type[typelen] = '\0';
 	taglen = sig_line - tag_line - strlen("tag \n");
 	item->tag = xmalloc(taglen + 1);
 	memcpy(item->tag, tag_line + 4, taglen);
 	item->tag[taglen] = '\0';
 
+	item->tagged = lookup_object_type(object, type);
+	if (item->tagged)
+		add_ref(&item->object, item->tagged);
+
 	return 0;
 }