commit graph: support sha256

include/git2/sys/commit_graph.h

@@ -28,7 +28,13 @@ GIT_BEGIN_DECL
  * @param objects_dir the path to a git objects directory.
  * @return Zero on success; -1 on failure.
  */
-GIT_EXTERN(int) git_commit_graph_open(git_commit_graph **cgraph_out, const char *objects_dir);
+GIT_EXTERN(int) git_commit_graph_open(
+	git_commit_graph **cgraph_out,
+	const char *objects_dir
+#ifdef GIT_EXPERIMENTAL_SHA256
+	, git_oid_t oid_type
+#endif
+	);
 
 /**
  * Frees commit-graph data. This should only be called when memory allocated
@@ -50,7 +56,11 @@ GIT_EXTERN(void) git_commit_graph_free(git_commit_graph *cgraph);
  */
 GIT_EXTERN(int) git_commit_graph_writer_new(
 		git_commit_graph_writer **out,
-		const char *objects_info_dir);
+		const char *objects_info_dir
+#ifdef GIT_EXPERIMENTAL_SHA256
+	, git_oid_t oid_type
+#endif
+		);
 
 /**
  * Free the commit-graph writer and its resources.

src/libgit2/commit_graph.h

@@ -30,6 +30,9 @@
 typedef struct git_commit_graph_file {
 	git_map graph_map;
 
+	/* The type of object IDs in the commit graph file. */
+	git_oid_t oid_type;
+
 	/* The OID Fanout table. */
 	const uint32_t *oid_fanout;
 	/* The total number of commits in the graph. */
@@ -84,10 +87,10 @@ typedef struct git_commit_graph_entry {
 	/* The index within the Extra Edge List of any parent after the first two. */
 	size_t extra_parents_index;
 
-	/* The SHA-1 hash of the root tree of the commit. */
+	/* The object ID of the root tree of the commit. */
 	git_oid tree_oid;
 
-	/* The SHA-1 hash of the requested commit. */
+	/* The object ID hash of the requested commit. */
 	git_oid sha1;
 } git_commit_graph_entry;
 
@@ -99,18 +102,28 @@ struct git_commit_graph {
 	/* The underlying commit-graph file. */
 	git_commit_graph_file *file;
 
+	/* The object ID types in the commit graph. */
+	git_oid_t oid_type;
+
 	/* Whether the commit-graph file was already checked for validity. */
 	bool checked;
 };
 
 /** Create a new commit-graph, optionally opening the underlying file. */
-int git_commit_graph_new(git_commit_graph **cgraph_out, const char *objects_dir, bool open_file);
+int git_commit_graph_new(
+	git_commit_graph **cgraph_out,
+	const char *objects_dir,
+	bool open_file,
+	git_oid_t oid_type);
 
 /** Validate the checksum of a commit graph */
 int git_commit_graph_validate(git_commit_graph *cgraph);
 
 /** Open and validate a commit-graph file. */
-int git_commit_graph_file_open(git_commit_graph_file **file_out, const char *path);
+int git_commit_graph_file_open(
+	git_commit_graph_file **file_out,
+	const char *path,
+	git_oid_t oid_type);
 
 /*
  * Attempt to get the git_commit_graph's commit-graph file. This object is
@@ -134,6 +147,9 @@ struct git_commit_graph_writer {
 	 */
 	git_str objects_info_dir;
 
+	/* The object ID type of the commit graph. */
+	git_oid_t oid_type;
+
 	/* The list of packed commits. */
 	git_vector commits;
 };

src/libgit2/odb.c

@@ -748,7 +748,8 @@ int git_odb__add_default_backends(
 		git_error_set(GIT_ERROR_ODB, "failed to acquire the odb lock");
 		return -1;
 	}
-	if (!db->cgraph && git_commit_graph_new(&db->cgraph, objects_dir, false) < 0) {
+	if (!db->cgraph &&
+	    git_commit_graph_new(&db->cgraph, objects_dir, false, db->options.oid_type) < 0) {
 		git_mutex_unlock(&db->lock);
 		return -1;
 	}

tests/libgit2/graph/commitgraph.c

@@ -16,7 +16,7 @@ void test_graph_commitgraph__parse(void)
 
 	cl_git_pass(git_repository_open(&repo, cl_fixture("testrepo.git")));
 	cl_git_pass(git_str_joinpath(&commit_graph_path, git_repository_path(repo), "objects/info/commit-graph"));
-	cl_git_pass(git_commit_graph_file_open(&file, git_str_cstr(&commit_graph_path)));
+	cl_git_pass(git_commit_graph_file_open(&file, git_str_cstr(&commit_graph_path), GIT_OID_SHA1));
 	cl_assert_equal_i(git_commit_graph_file_needs_refresh(file, git_str_cstr(&commit_graph_path)), 0);
 
 	cl_git_pass(git_oid__fromstr(&id, "5001298e0c09ad9c34e4249bc5801c75e9754fa5", GIT_OID_SHA1));
@@ -60,7 +60,7 @@ void test_graph_commitgraph__parse_octopus_merge(void)
 
 	cl_git_pass(git_repository_open(&repo, cl_fixture("merge-recursive/.gitted")));
 	cl_git_pass(git_str_joinpath(&commit_graph_path, git_repository_path(repo), "objects/info/commit-graph"));
-	cl_git_pass(git_commit_graph_file_open(&file, git_str_cstr(&commit_graph_path)));
+	cl_git_pass(git_commit_graph_file_open(&file, git_str_cstr(&commit_graph_path), GIT_OID_SHA1));
 
 	cl_git_pass(git_oid__fromstr(&id, "d71c24b3b113fd1d1909998c5bfe33b86a65ee03", GIT_OID_SHA1));
 	cl_git_pass(git_commit_graph_entry_find(&e, file, &id, GIT_OID_SHA1_HEXSIZE));
@@ -103,7 +103,12 @@ void test_graph_commitgraph__writer(void)
 	cl_git_pass(git_repository_open(&repo, cl_fixture("testrepo.git")));
 
 	cl_git_pass(git_str_joinpath(&path, git_repository_path(repo), "objects/info"));
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	cl_git_pass(git_commit_graph_writer_new(&w, git_str_cstr(&path), GIT_OID_SHA1));
+#else
 	cl_git_pass(git_commit_graph_writer_new(&w, git_str_cstr(&path)));
+#endif
 
 	/* This is equivalent to `git commit-graph write --reachable`. */
 	cl_git_pass(git_revwalk_new(&walk, repo));
@@ -135,7 +140,11 @@ void test_graph_commitgraph__validate(void)
 	cl_git_pass(git_str_joinpath(&objects_dir, git_repository_path(repo), "objects"));
 
 	/* git_commit_graph_open() calls git_commit_graph_validate() */
+#ifdef GIT_EXPERIMENTAL_SHA256
+	cl_git_pass(git_commit_graph_open(&cgraph, git_str_cstr(&objects_dir), GIT_OID_SHA1));
+#else
 	cl_git_pass(git_commit_graph_open(&cgraph, git_str_cstr(&objects_dir)));
+#endif
 
 	git_commit_graph_free(cgraph);
 	git_str_dispose(&objects_dir);
@@ -158,7 +167,11 @@ void test_graph_commitgraph__validate_corrupt(void)
 	cl_must_pass(p_close(fd));
 
 	/* git_commit_graph_open() calls git_commit_graph_validate() */
+#ifdef GIT_EXPERIMENTAL_SHA256
+	cl_git_fail(git_commit_graph_open(&cgraph, cl_git_sandbox_path(1, "testrepo.git", "objects", NULL), GIT_OID_SHA1));
+#else
 	cl_git_fail(git_commit_graph_open(&cgraph, cl_git_sandbox_path(1, "testrepo.git", "objects", NULL)));
+#endif
 
 	git_commit_graph_free(cgraph);
 	git_repository_free(repo);