commit: create get_commit_tree() method

While walking the commit graph, we load struct commit objects into
the object cache. During this process, we also load struct tree
objects for the root tree of each of these commits. We load these
objects even if we are only computing commit reachability information,
such as a merge base or ahead/behind information.

Create get_commit_tree() as a first step to removing direct
references to the 'maybe_tree' member of struct commit.

Create get_commit_tree_oid() as a shortcut for several references
to "&commit->maybe_tree->object.oid" in the codebase.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/commit.c b/commit.c
index fbc092808cb3ddfecc82abc4873e941331a31888..aea2ca1f8ba307f540f17d4f4b93071f9eb45b5f 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -296,6 +296,16 @@ void free_commit_buffer(struct commit *commit)
        }
 }
 
+struct tree *get_commit_tree(const struct commit *commit)
+{
+       return commit->maybe_tree;
+}
+
+struct object_id *get_commit_tree_oid(const struct commit *commit)
+{
+       return &get_commit_tree(commit)->object.oid;
+}
+
 const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 {
        struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit);

diff --git a/commit.h b/commit.h
index c4d6e6e06465904d79da70662ede18cccf00621d..dc4bf97d9f3b74da1176d552f067e00b72a2d7fb 100644 (file)
--- a/commit.h
+++ b/commit.h
@@ -102,6 +102,9 @@ void unuse_commit_buffer(const struct commit *, const void *buffer);
  */
 void free_commit_buffer(struct commit *);
 
+struct tree *get_commit_tree(const struct commit *);
+struct object_id *get_commit_tree_oid(const struct commit *);
+
 /*
  * Disassociate any cached object buffer from the commit, but do not free it.
  * The buffer (or NULL, if none) is returned.