Remove "tree->entries" tree-entry list from tree parser

Instead, just use the tree buffer directly, and use the tree-walk
infrastructure to walk the buffers instead of the tree-entry list.

The tree-entry list is inefficient, and generates tons of small
allocations for no good reason. The tree-walk infrastructure is
generally no harder to use than following a linked list, and allows
us to do most tree parsing in-place.

Some programs still use the old tree-entry lists, and are a bit
painful to convert without major surgery. For them we have a helper
function that creates a temporary tree-entry list on demand.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

fetch.c

@@ -41,16 +41,22 @@ static int process_tree(struct tree *tree)
 	if (parse_tree(tree))
 		return -1;
 
-	entry = tree->entries;
-	tree->entries = NULL;
+	entry = create_tree_entry_list(tree);
 	while (entry) {
 		struct tree_entry_list *next = entry->next;
-		if (process(entry->item.any))
-			return -1;
-		free(entry->name);
+
+		if (entry->directory) {
+			struct tree *tree = lookup_tree(entry->sha1);
+			process_tree(tree);
+		} else {
+			struct blob *blob = lookup_blob(entry->sha1);
+			process(&blob->object);
+		}
 		free(entry);
 		entry = next;
 	}
+	free(tree->buffer);
+	tree->buffer = NULL;
 	return 0;
 }