[#1103] node: Reduce amount of lines for method StorageEngine.head

Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

pkg/local_object_storage/engine/head.go

@@ -67,20 +67,17 @@ func (e *StorageEngine) Head(ctx context.Context, prm HeadPrm) (res HeadRes, err
 func (e *StorageEngine) head(ctx context.Context, prm HeadPrm) (HeadRes, error) {
 	ctx, span := tracing.StartSpanFromContext(ctx, "StorageEngine.head")
 	defer span.End()
-
 	if e.metrics != nil {
 		defer elapsed("Head", e.metrics.AddMethodDuration)()
 	}
 
 	var (
-		head  *objectSDK.Object
-		siErr *objectSDK.SplitInfoError
-		outSI *objectSDK.SplitInfo
-
+		head     *objectSDK.Object
+		siErr    *objectSDK.SplitInfoError
+		outSI    *objectSDK.SplitInfo
 		outError error = new(apistatus.ObjectNotFound)
+		shPrm    shard.HeadPrm
 	)
-
-	var shPrm shard.HeadPrm
 	shPrm.SetAddress(prm.addr)
 	shPrm.SetRaw(prm.raw)
 
@@ -94,44 +91,34 @@ func (e *StorageEngine) head(ctx context.Context, prm HeadPrm) (HeadRes, error)
 				if outSI == nil {
 					outSI = objectSDK.NewSplitInfo()
 				}
-
 				util.MergeSplitInfo(siErr.SplitInfo(), outSI)
-
 				_, withLink := outSI.Link()
 				_, withLast := outSI.LastPart()
-
 				// stop iterating over shards if SplitInfo structure is complete
 				if withLink && withLast {
 					return true
 				}
-
 				return false
 			case client.IsErrObjectAlreadyRemoved(err):
 				outError = err
-
 				return true // stop, return it back
 			case shard.IsErrObjectExpired(err):
 				// object is found but should not
 				// be returned
 				outError = new(apistatus.ObjectNotFound)
-
 				return true
 			default:
 				e.reportShardError(sh, "could not head object from shard", err)
 				return false
 			}
 		}
-
 		head = res.Object()
-
 		return true
 	})
 
 	if outSI != nil {
 		return HeadRes{}, logicerr.Wrap(objectSDK.NewSplitInfoError(outSI))
-	}
-
-	if head == nil {
+	} else if head == nil {
 		return HeadRes{}, outError
 	}