[#477] Provide aggregation of tags and locks in layer.Client

Adopts GetObjectTaggingAndLock method from
TreeClient in layer.Client with caching.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

api/layer/compound.go

@@ -0,0 +1,47 @@
+package layer
+
+import (
+	"context"
+	errorsStd "errors"
+
+	"github.com/nspcc-dev/neofs-s3-gw/api/data"
+	"github.com/nspcc-dev/neofs-s3-gw/api/errors"
+	"go.uber.org/zap"
+)
+
+func (n *layer) GetObjectTaggingAndLock(ctx context.Context, objVersion *ObjectVersion) (map[string]string, *data.LockInfo, error) {
+	var (
+		err  error
+		tags map[string]string
+	)
+
+	tags = n.systemCache.GetTagging(objectTaggingCacheKey(objVersion))
+	lockInfo := n.systemCache.GetLockInfo(lockObjectKey(objVersion))
+
+	if tags != nil && lockInfo != nil {
+		return tags, lockInfo, nil
+	}
+
+	version, err := n.getNodeVersion(ctx, objVersion)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	tags, lockInfo, err = n.treeService.GetObjectTaggingAndLock(ctx, &objVersion.BktInfo.CID, version)
+	if err != nil {
+		if errorsStd.Is(err, ErrNodeNotFound) {
+			return nil, nil, errors.GetAPIError(errors.ErrNoSuchKey)
+		}
+		return nil, nil, err
+	}
+
+	if err = n.systemCache.PutTagging(objectTaggingCacheKey(objVersion), tags); err != nil {
+		n.log.Error("couldn't cache system object", zap.Error(err))
+	}
+
+	if err = n.systemCache.PutLockInfo(lockObjectKey(objVersion), lockInfo); err != nil {
+		n.log.Error("couldn't cache system object", zap.Error(err))
+	}
+
+	return tags, lockInfo, nil
+}

api/layer/layer.go

@@ -248,6 +248,11 @@ type (
 
 		PutBucketNotificationConfiguration(ctx context.Context, p *PutBucketNotificationConfigurationParams) error
 		GetBucketNotificationConfiguration(ctx context.Context, bktInfo *data.BucketInfo) (*data.NotificationConfiguration, error)
+
+		// Compound methods for optimizations
+
+		// GetObjectTaggingAndLock unifies GetObjectTagging and GetLock methods in single tree service invocation.
+		GetObjectTaggingAndLock(ctx context.Context, p *ObjectVersion) (map[string]string, *data.LockInfo, error)
 	}
 )