tree-diff: convert diff_root_tree_sha1 to struct object_id

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fast-export.c

@@ -566,7 +566,7 @@ static void handle_commit(struct commit *commit, struct rev_info *rev)
 			       commit->tree->object.oid.hash, "", &rev->diffopt);
 	}
 	else
-		diff_root_tree_sha1(commit->tree->object.oid.hash,
+		diff_root_tree_oid(&commit->tree->object.oid,
 				   "", &rev->diffopt);
 
 	/* Export the referenced blobs, and remember the marks. */

diff.h

@@ -215,7 +215,7 @@ extern struct combine_diff_path *diff_tree_paths(
 	struct strbuf *base, struct diff_options *opt);
 extern int diff_tree_sha1(const unsigned char *old, const unsigned char *new,
 			  const char *base, struct diff_options *opt);
-extern int diff_root_tree_sha1(const unsigned char *new, const char *base,
+extern int diff_root_tree_oid(const struct object_id *new_oid, const char *base,
 			      struct diff_options *opt);
 
 struct combine_diff_path {

log-tree.c

@@ -803,7 +803,7 @@ static int log_tree_diff(struct rev_info *opt, struct commit *commit, struct log
 	parents = get_saved_parents(opt, commit);
 	if (!parents) {
 		if (opt->show_root_diff) {
-			diff_root_tree_sha1(oid->hash, "", &opt->diffopt);
+			diff_root_tree_oid(oid, "", &opt->diffopt);
 			log_tree_diff_flush(opt);
 		}
 		return !opt->loginfo;

patch-ids.c

@@ -20,7 +20,7 @@ int commit_patch_id(struct commit *commit, struct diff_options *options,
 		diff_tree_sha1(commit->parents->item->object.oid.hash,
 			       commit->object.oid.hash, "", options);
 	else
-		diff_root_tree_sha1(commit->object.oid.hash, "", options);
+		diff_root_tree_oid(&commit->object.oid, "", options);
 	diffcore_std(options);
 	return diff_flush_patch_id(options, oid, diff_header_only);
 }

tree-diff.c

@@ -711,7 +711,7 @@ int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const cha
 	return retval;
 }
 
-int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
+int diff_root_tree_oid(const struct object_id *new_oid, const char *base, struct diff_options *opt)
 {
-	return diff_tree_sha1(NULL, new, base, opt);
+	return diff_tree_sha1(NULL, new_oid->hash, base, opt);
 }