pack-bitmap.c: introduce 'bitmap_num_objects()'

A subsequent patch to support reading MIDX bitmaps will be less noisy
after extracting a generic function to return how many objects are
contained in a bitmap.

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

pack-bitmap.c

@@ -136,6 +136,11 @@ static struct ewah_bitmap *read_bitmap_1(struct bitmap_index *index)
 	return b;
 }
 
+static uint32_t bitmap_num_objects(struct bitmap_index *index)
+{
+	return index->pack->num_objects;
+}
+
 static int load_bitmap_header(struct bitmap_index *index)
 {
 	struct bitmap_disk_header *header = (void *)index->map;
@@ -154,7 +159,7 @@ static int load_bitmap_header(struct bitmap_index *index)
 	/* Parse known bitmap format options */
 	{
 		uint32_t flags = ntohs(header->options);
-		size_t cache_size = st_mult(index->pack->num_objects, sizeof(uint32_t));
+		size_t cache_size = st_mult(bitmap_num_objects(index), sizeof(uint32_t));
 		unsigned char *index_end = index->map + index->map_size - the_hash_algo->rawsz;
 
 		if ((flags & BITMAP_OPT_FULL_DAG) == 0)
@@ -404,7 +409,7 @@ static inline int bitmap_position_extended(struct bitmap_index *bitmap_git,
 
 	if (pos < kh_end(positions)) {
 		int bitmap_pos = kh_value(positions, pos);
-		return bitmap_pos + bitmap_git->pack->num_objects;
+		return bitmap_pos + bitmap_num_objects(bitmap_git);
 	}
 
 	return -1;
@@ -456,7 +461,7 @@ static int ext_index_add_object(struct bitmap_index *bitmap_git,
 		bitmap_pos = kh_value(eindex->positions, hash_pos);
 	}
 
-	return bitmap_pos + bitmap_git->pack->num_objects;
+	return bitmap_pos + bitmap_num_objects(bitmap_git);
 }
 
 struct bitmap_show_data {
@@ -673,7 +678,7 @@ static void show_extended_objects(struct bitmap_index *bitmap_git,
 	for (i = 0; i < eindex->count; ++i) {
 		struct object *obj;
 
-		if (!bitmap_get(objects, bitmap_git->pack->num_objects + i))
+		if (!bitmap_get(objects, bitmap_num_objects(bitmap_git) + i))
 			continue;
 
 		obj = eindex->objects[i];
@@ -832,7 +837,7 @@ static void filter_bitmap_exclude_type(struct bitmap_index *bitmap_git,
 	 * them individually.
 	 */
 	for (i = 0; i < eindex->count; i++) {
-		uint32_t pos = i + bitmap_git->pack->num_objects;
+		uint32_t pos = i + bitmap_num_objects(bitmap_git);
 		if (eindex->objects[i]->type == type &&
 		    bitmap_get(to_filter, pos) &&
 		    !bitmap_get(tips, pos))
@@ -859,7 +864,7 @@ static unsigned long get_size_by_pos(struct bitmap_index *bitmap_git,
 
 	oi.sizep = &size;
 
-	if (pos < pack->num_objects) {
+	if (pos < bitmap_num_objects(bitmap_git)) {
 		off_t ofs = pack_pos_to_offset(pack, pos);
 		if (packed_object_info(the_repository, pack, ofs, &oi) < 0) {
 			struct object_id oid;
@@ -869,7 +874,7 @@ static unsigned long get_size_by_pos(struct bitmap_index *bitmap_git,
 		}
 	} else {
 		struct eindex *eindex = &bitmap_git->ext_index;
-		struct object *obj = eindex->objects[pos - pack->num_objects];
+		struct object *obj = eindex->objects[pos - bitmap_num_objects(bitmap_git)];
 		if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)
 			die(_("unable to get size of %s"), oid_to_hex(&obj->oid));
 	}
@@ -911,7 +916,7 @@ static void filter_bitmap_blob_limit(struct bitmap_index *bitmap_git,
 	}
 
 	for (i = 0; i < eindex->count; i++) {
-		uint32_t pos = i + bitmap_git->pack->num_objects;
+		uint32_t pos = i + bitmap_num_objects(bitmap_git);
 		if (eindex->objects[i]->type == OBJ_BLOB &&
 		    bitmap_get(to_filter, pos) &&
 		    !bitmap_get(tips, pos) &&
@@ -1137,8 +1142,8 @@ static void try_partial_reuse(struct bitmap_index *bitmap_git,
 	enum object_type type;
 	unsigned long size;
 
-	if (pos >= bitmap_git->pack->num_objects)
+	if (pos >= bitmap_num_objects(bitmap_git))
-		return; /* not actually in the pack */
+		return; /* not actually in the pack or MIDX */
 
 	offset = header = pack_pos_to_offset(bitmap_git->pack, pos);
 	type = unpack_object_header(bitmap_git->pack, w_curs, &offset, &size);
@@ -1204,6 +1209,7 @@ int reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
 	struct pack_window *w_curs = NULL;
 	size_t i = 0;
 	uint32_t offset;
+	uint32_t objects_nr = bitmap_num_objects(bitmap_git);
 
 	assert(result);
 
@@ -1211,8 +1217,8 @@ int reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
 		i++;
 
 	/* Don't mark objects not in the packfile */
-	if (i > bitmap_git->pack->num_objects / BITS_IN_EWORD)
+	if (i > objects_nr / BITS_IN_EWORD)
-		i = bitmap_git->pack->num_objects / BITS_IN_EWORD;
+		i = objects_nr / BITS_IN_EWORD;
 
 	reuse = bitmap_word_alloc(i);
 	memset(reuse->words, 0xFF, i * sizeof(eword_t));
@@ -1296,7 +1302,7 @@ static uint32_t count_object_type(struct bitmap_index *bitmap_git,
 
 	for (i = 0; i < eindex->count; ++i) {
 		if (eindex->objects[i]->type == type &&
-			bitmap_get(objects, bitmap_git->pack->num_objects + i))
+			bitmap_get(objects, bitmap_num_objects(bitmap_git) + i))
 			count++;
 	}
 
@@ -1517,7 +1523,7 @@ uint32_t *create_bitmap_mapping(struct bitmap_index *bitmap_git,
 	uint32_t i, num_objects;
 	uint32_t *reposition;
 
-	num_objects = bitmap_git->pack->num_objects;
+	num_objects = bitmap_num_objects(bitmap_git);
 	CALLOC_ARRAY(reposition, num_objects);
 
 	for (i = 0; i < num_objects; ++i) {
@@ -1600,7 +1606,6 @@ static off_t get_disk_usage_for_type(struct bitmap_index *bitmap_git,
 static off_t get_disk_usage_for_extended(struct bitmap_index *bitmap_git)
 {
 	struct bitmap *result = bitmap_git->result;
-	struct packed_git *pack = bitmap_git->pack;
 	struct eindex *eindex = &bitmap_git->ext_index;
 	off_t total = 0;
 	struct object_info oi = OBJECT_INFO_INIT;
@@ -1612,7 +1617,7 @@ static off_t get_disk_usage_for_extended(struct bitmap_index *bitmap_git)
 	for (i = 0; i < eindex->count; i++) {
 		struct object *obj = eindex->objects[i];
 
-		if (!bitmap_get(result, pack->num_objects + i))
+		if (!bitmap_get(result, bitmap_num_objects(bitmap_git) + i))
 			continue;
 
 		if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)