pack-bitmap: factor out 'add_commit_to_bitmap()'

'find_objects()' currently needs to interact with the bitmaps khash
pretty closely. To make 'find_objects()' read a little more
straightforwardly, remove some of the khash-level details into a new
function that describes what it does: 'add_commit_to_bitmap()'.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pack-bitmap.c

@@ -521,6 +521,23 @@ static int should_include(struct commit *commit, void *_data)
 	return 1;
 }
 
+static int add_commit_to_bitmap(struct bitmap_index *bitmap_git,
+				struct bitmap **base,
+				struct commit *commit)
+{
+	struct ewah_bitmap *or_with = bitmap_for_commit(bitmap_git, commit);
+
+	if (!or_with)
+		return 0;
+
+	if (*base == NULL)
+		*base = ewah_to_bitmap(or_with);
+	else
+		bitmap_or_ewah(*base, or_with);
+
+	return 1;
+}
+
 static struct bitmap *find_objects(struct bitmap_index *bitmap_git,
 				   struct rev_info *revs,
 				   struct object_list *roots,
@@ -544,21 +561,10 @@ static struct bitmap *find_objects(struct bitmap_index *bitmap_git,
 		struct object *object = roots->item;
 		roots = roots->next;
 
-		if (object->type == OBJ_COMMIT) {
-			khiter_t pos = kh_get_oid_map(bitmap_git->bitmaps, object->oid);
-
-			if (pos < kh_end(bitmap_git->bitmaps)) {
-				struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, pos);
-				struct ewah_bitmap *or_with = lookup_stored_bitmap(st);
-
-				if (base == NULL)
-					base = ewah_to_bitmap(or_with);
-				else
-					bitmap_or_ewah(base, or_with);
-
-				object->flags |= SEEN;
-				continue;
-			}
+		if (object->type == OBJ_COMMIT &&
+		    add_commit_to_bitmap(bitmap_git, &base, (struct commit *)object)) {
+			object->flags |= SEEN;
+			continue;
 		}
 
 		object_list_insert(object, &not_mapped);