treewide: rename tree to maybe_tree

Using the commit-graph file to walk commit history removes the large
cost of parsing commits during the walk. This exposes a performance
issue: lookup_tree() takes a large portion of the computation time,
even when Git never uses those trees.

In anticipation of lazy-loading these trees, rename the 'tree' member
of struct commit to 'maybe_tree'. This serves two purposes: it hints
at the future role of possibly being NULL even if the commit has a
valid tree, and it allows for unambiguous transformation from simple
member access (i.e. commit->maybe_tree) to method access.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Derrick Stolee
2018-04-06 19:09:32 +00:00
committed by Junio C Hamano
parent 2d5792f071
commit 891435d55d
24 changed files with 65 additions and 64 deletions

4
tree.c
View File

@@ -109,7 +109,7 @@ static int read_tree_1(struct tree *tree, struct strbuf *base,
oid_to_hex(entry.oid),
base->buf, entry.path);
oidcpy(&oid, &commit->tree->object.oid);
oidcpy(&oid, &commit->maybe_tree->object.oid);
}
else
continue;
@@ -248,7 +248,7 @@ struct tree *parse_tree_indirect(const struct object_id *oid)
if (obj->type == OBJ_TREE)
return (struct tree *) obj;
else if (obj->type == OBJ_COMMIT)
obj = &(((struct commit *) obj)->tree->object);
obj = &(((struct commit *) obj)->maybe_tree->object);
else if (obj->type == OBJ_TAG)
obj = ((struct tag *) obj)->tagged;
else