[PATCH] Object library enhancements

Add function to look up an object which is entirely unknown, so that
it can be put in a list. Various other functions related to lists of
objects.

Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

object.c

@@ -99,7 +99,9 @@ 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)) {
+	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;
@@ -113,6 +115,27 @@ struct object *lookup_object_type(const unsigned char *sha1, const char *type)
 	}
 }
 
+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;
+	}
+	return obj;
+}
+
 struct object *parse_object(const unsigned char *sha1)
 {
 	unsigned long size;
@@ -150,3 +173,33 @@ struct object *parse_object(const unsigned char *sha1)
 	}
 	return NULL;
 }
+
+struct object_list *object_list_insert(struct object *item,
+				       struct object_list **list_p)
+{
+	struct object_list *new_list = xmalloc(sizeof(struct object_list));
+        new_list->item = item;
+        new_list->next = *list_p;
+        *list_p = new_list;
+        return new_list;
+}
+
+unsigned object_list_length(struct object_list *list)
+{
+	unsigned ret = 0;
+	while (list) {
+		list = list->next;
+		ret++;
+	}
+	return ret;
+}
+
+int object_list_contains(struct object_list *list, struct object *obj)
+{
+	while (list) {
+		if (list->item == obj)
+			return 1;
+		list = list->next;
+	}
+	return 0;
+}

object.h

@@ -31,8 +31,18 @@ void created_object(const unsigned char *sha1, struct object *obj);
 /** Returns the object, having parsed it to find out what it is. **/
 struct object *parse_object(const unsigned char *sha1);
 
+/** Returns the object, with potentially excess memory allocated. **/
+struct object *lookup_unknown_object(const unsigned  char *sha1);
+
 void add_ref(struct object *refer, struct object *target);
 
 void mark_reachable(struct object *obj, unsigned int mask);
 
+struct object_list *object_list_insert(struct object *item, 
+				       struct object_list **list_p);
+
+unsigned object_list_length(struct object_list *list);
+
+int object_list_contains(struct object_list *list, struct object *obj);
+
 #endif /* OBJECT_H */

tree.h

@@ -14,6 +14,7 @@ struct tree_entry_list {
 	unsigned int mode;
 	char *name;
 	union {
+		struct object *any;
 		struct tree *tree;
 		struct blob *blob;
 	} item;