[#1692] metabase: Remove useless count variable

It is always equal to `len(to)`.

Change-Id: Id7a4c26e9711216b78f96e6b2511efa0773e3471
Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

pkg/local_object_storage/metabase/bucket_cache.go

@@ -14,10 +14,7 @@ type bucketCache struct {
 }
 
 func newBucketCache() *bucketCache {
-	return &bucketCache{
-		expired: make(map[cid.ID]*bbolt.Bucket),
-		primary: make(map[cid.ID]*bbolt.Bucket),
-	}
+	return &bucketCache{}
 }
 
 func getLockedBucket(bc *bucketCache, tx *bbolt.Tx) *bbolt.Bucket {
@@ -56,7 +53,7 @@ func getExpiredBucket(bc *bucketCache, tx *bbolt.Tx, cnr cid.ID) *bbolt.Bucket {
 		bucketName = objectToExpirationEpochBucketName(cnr, bucketName)
 		return tx.Bucket(bucketName)
 	}
-	return getMappedBucket(bc.expired, tx, objectToExpirationEpochBucketName, cnr)
+	return getMappedBucket(&bc.expired, tx, objectToExpirationEpochBucketName, cnr)
 }
 
 func getPrimaryBucket(bc *bucketCache, tx *bbolt.Tx, cnr cid.ID) *bbolt.Bucket {
@@ -65,17 +62,21 @@ func getPrimaryBucket(bc *bucketCache, tx *bbolt.Tx, cnr cid.ID) *bbolt.Bucket {
 		bucketName = primaryBucketName(cnr, bucketName)
 		return tx.Bucket(bucketName)
 	}
-	return getMappedBucket(bc.primary, tx, primaryBucketName, cnr)
+	return getMappedBucket(&bc.primary, tx, primaryBucketName, cnr)
 }
 
-func getMappedBucket(m map[cid.ID]*bbolt.Bucket, tx *bbolt.Tx, nameFunc func(cid.ID, []byte) []byte, cnr cid.ID) *bbolt.Bucket {
-	value, ok := m[cnr]
+func getMappedBucket(m *map[cid.ID]*bbolt.Bucket, tx *bbolt.Tx, nameFunc func(cid.ID, []byte) []byte, cnr cid.ID) *bbolt.Bucket {
+	value, ok := (*m)[cnr]
 	if ok {
 		return value
 	}
 
+	if *m == nil {
+		*m = make(map[cid.ID]*bbolt.Bucket, 1)
+	}
+
 	bucketName := make([]byte, bucketKeySize)
 	bucketName = nameFunc(cnr, bucketName)
-	m[cnr] = getBucket(&value, tx, bucketName)
+	(*m)[cnr] = getBucket(&value, tx, bucketName)
 	return value
 }

pkg/local_object_storage/metabase/list.go

@@ -139,8 +139,7 @@ func (db *DB) listWithCursor(tx *bbolt.Tx, result []objectcore.Info, count int,
 
 	var containerID cid.ID
 	var offset []byte
-	graveyardBkt := tx.Bucket(graveyardBucketName)
-	garbageBkt := tx.Bucket(garbageBucketName)
+	bc := newBucketCache()
 
 	rawAddr := make([]byte, cidSize, addressKeySize)
 
@@ -169,7 +168,7 @@ loop:
 		bkt := tx.Bucket(name)
 		if bkt != nil {
 			copy(rawAddr, cidRaw)
-			result, offset, cursor, err = selectNFromBucket(bkt, objType, graveyardBkt, garbageBkt, rawAddr, containerID,
+			result, offset, cursor, err = selectNFromBucket(bc, bkt, objType, rawAddr, containerID,
 				result, count, cursor, threshold, currEpoch)
 			if err != nil {
 				return nil, nil, err
@@ -204,9 +203,10 @@ loop:
 
 // selectNFromBucket similar to selectAllFromBucket but uses cursor to find
 // object to start selecting from. Ignores inhumed objects.
-func selectNFromBucket(bkt *bbolt.Bucket, // main bucket
+func selectNFromBucket(
+	bc *bucketCache,
+	bkt *bbolt.Bucket, // main bucket
 	objType objectSDK.Type, // type of the objects stored in the main bucket
-	graveyardBkt, garbageBkt *bbolt.Bucket, // cached graveyard buckets
 	cidRaw []byte, // container ID prefix, optimization
 	cnt cid.ID, // container ID
 	to []objectcore.Info, // listing result
@@ -219,7 +219,6 @@ func selectNFromBucket(bkt *bbolt.Bucket, // main bucket
 		cursor = new(Cursor)
 	}
 
-	count := len(to)
 	c := bkt.Cursor()
 	k, v := c.First()
 
@@ -231,7 +230,7 @@ func selectNFromBucket(bkt *bbolt.Bucket, // main bucket
 	}
 
 	for ; k != nil; k, v = c.Next() {
-		if count >= limit {
+		if len(to) >= limit {
 			break
 		}
 
@@ -241,6 +240,8 @@ func selectNFromBucket(bkt *bbolt.Bucket, // main bucket
 		}
 
 		offset = k
+		graveyardBkt := getGraveyardBucket(bc, bkt.Tx())
+		garbageBkt := getGarbageBucket(bc, bkt.Tx())
 		if inGraveyardWithKey(append(cidRaw, k...), graveyardBkt, garbageBkt) > 0 {
 			continue
 		}
@@ -251,7 +252,7 @@ func selectNFromBucket(bkt *bbolt.Bucket, // main bucket
 		}
 
 		expEpoch, hasExpEpoch := hasExpirationEpoch(&o)
-		if hasExpEpoch && expEpoch < currEpoch && !objectLocked(bkt.Tx(), cnt, obj) {
+		if hasExpEpoch && expEpoch < currEpoch && !objectLockedWithCache(bc, bkt.Tx(), cnt, obj) {
 			continue
 		}
 
@@ -273,7 +274,6 @@ func selectNFromBucket(bkt *bbolt.Bucket, // main bucket
 		a.SetContainer(cnt)
 		a.SetObject(obj)
 		to = append(to, objectcore.Info{Address: a, Type: objType, IsLinkingObject: isLinkingObj, ECInfo: ecInfo})
-		count++
 	}
 
 	return to, offset, cursor, nil

pkg/local_object_storage/metabase/list_test.go

@@ -59,7 +59,7 @@ func benchmarkListWithCursor(b *testing.B, db *meta.DB, batchSize int) {
 	for range b.N {
 		res, err := db.ListWithCursor(context.Background(), prm)
 		if err != nil {
-			if errors.Is(err, meta.ErrEndOfListing) {
+			if !errors.Is(err, meta.ErrEndOfListing) {
 				b.Fatalf("error: %v", err)
 			}
 			prm.SetCursor(nil)