combine-diff: convert diff_tree_combined to struct object_id

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

builtin/diff.c

@@ -194,7 +194,7 @@ static int builtin_diff_combined(struct rev_info *revs,
 		revs->dense_combined_merges = revs->combine_merges = 1;
 	for (i = 1; i < ents; i++)
 		oid_array_append(&parents, &ent[i].item->oid);
-	diff_tree_combined(ent[0].item->oid.hash, &parents,
+	diff_tree_combined(&ent[0].item->oid, &parents,
 			   revs->dense_combined_merges, revs);
 	oid_array_clear(&parents);
 	return 0;

combine-diff.c

@@ -1384,7 +1384,7 @@ static struct combine_diff_path *find_paths_multitree(
 }
 
 
-void diff_tree_combined(const unsigned char *sha1,
+void diff_tree_combined(const struct object_id *oid,
 			const struct oid_array *parents,
 			int dense,
 			struct rev_info *rev)
@@ -1448,11 +1448,11 @@ void diff_tree_combined(const unsigned char *sha1,
 		 * diff(sha1,parent_i) for all i to do the job, specifically
 		 * for parent0.
 		 */
-		paths = find_paths_generic(sha1, parents, &diffopts);
+		paths = find_paths_generic(oid->hash, parents, &diffopts);
 	}
 	else {
 		int stat_opt;
-		paths = find_paths_multitree(sha1, parents, &diffopts);
+		paths = find_paths_multitree(oid->hash, parents, &diffopts);
 
 		/*
 		 * show stat against the first parent even
@@ -1463,7 +1463,7 @@ void diff_tree_combined(const unsigned char *sha1,
 		if (stat_opt) {
 			diffopts.output_format = stat_opt;
 
-			diff_tree_sha1(parents->oid[0].hash, sha1, "", &diffopts);
+			diff_tree_sha1(parents->oid[0].hash, oid->hash, "", &diffopts);
 			diffcore_std(&diffopts);
 			if (opt->orderfile)
 				diffcore_order(opt->orderfile);
@@ -1539,6 +1539,6 @@ void diff_tree_combined_merge(const struct commit *commit, int dense,
 		oid_array_append(&parents, &parent->item->object.oid);
 		parent = parent->next;
 	}
-	diff_tree_combined(commit->object.oid.hash, &parents, dense, rev);
+	diff_tree_combined(&commit->object.oid, &parents, dense, rev);
 	oid_array_clear(&parents);
 }

diff.h

@@ -236,7 +236,7 @@ struct combine_diff_path {
 extern void show_combined_diff(struct combine_diff_path *elem, int num_parent,
 			      int dense, struct rev_info *);
 
-extern void diff_tree_combined(const unsigned char *sha1, const struct oid_array *parents, int dense, struct rev_info *rev);
+extern void diff_tree_combined(const struct object_id *oid, const struct oid_array *parents, int dense, struct rev_info *rev);
 
 extern void diff_tree_combined_merge(const struct commit *commit, int dense, struct rev_info *rev);