commit: create get_commit_tree() method

derrickstolee · gitster · commit 5bb03de102b4 · 2018-04-11T10:47:16.000+09:00
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 "&amp;commit-&gt;maybe_tree-&gt;object.oid" in the codebase.

Signed-off-by: Derrick Stolee &lt;dstolee@microsoft.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git 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
@@ -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.

Original file line number	Diff line number	Diff line change
`@@ -296,6 +296,16 @@ void free_commit_buffer(struct commit *commit)`
`296`	`296`	`}`
`297`	`297`	`}`
`298`	`298`
	`299`	`+struct tree get_commit_tree(const struct commit commit)`
	`300`	`+{`
	`301`	`+ return commit->maybe_tree;`
	`302`	`+}`
	`303`	`+`
	`304`	`+struct object_id get_commit_tree_oid(const struct commit commit)`
	`305`	`+{`
	`306`	`+ return &get_commit_tree(commit)->object.oid;`
	`307`	`+}`
	`308`	`+`
`299`	`309`	`const void detach_commit_buffer(struct commit commit, unsigned long *sizep)`
`300`	`310`	`{`
`301`	`311`	`struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit);`