[#1460] shard: Do not use pointers as the results

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

pkg/local_object_storage/shard/container.go

@@ -24,13 +24,13 @@ func (r ContainerSizeRes) Size() uint64 {
 	return r.size
 }
 
-func (s *Shard) ContainerSize(prm ContainerSizePrm) (*ContainerSizeRes, error) {
+func (s *Shard) ContainerSize(prm ContainerSizePrm) (ContainerSizeRes, error) {
 	size, err := s.metaBase.ContainerSize(prm.cnr)
 	if err != nil {
-		return nil, fmt.Errorf("could not get container size: %w", err)
+		return ContainerSizeRes{}, fmt.Errorf("could not get container size: %w", err)
 	}
 
-	return &ContainerSizeRes{
+	return ContainerSizeRes{
 		size: size,
 	}, nil
 }

pkg/local_object_storage/shard/delete.go

@@ -28,9 +28,9 @@ func (p *DeletePrm) WithAddresses(addr ...oid.Address) {
 
 // Delete removes data from the shard's writeCache, metaBase and
 // blobStor.
-func (s *Shard) Delete(prm DeletePrm) (*DeleteRes, error) {
+func (s *Shard) Delete(prm DeletePrm) (DeleteRes, error) {
 	if s.GetMode() != ModeReadWrite {
-		return nil, ErrReadOnlyMode
+		return DeleteRes{}, ErrReadOnlyMode
 	}
 
 	ln := len(prm.addr)
@@ -63,7 +63,7 @@ func (s *Shard) Delete(prm DeletePrm) (*DeleteRes, error) {
 
 	err := meta.Delete(s.metaBase, prm.addr...)
 	if err != nil {
-		return nil, err // stop on metabase error ?
+		return DeleteRes{}, err // stop on metabase error ?
 	}
 
 	for i := range prm.addr { // delete small object
@@ -93,5 +93,5 @@ func (s *Shard) Delete(prm DeletePrm) (*DeleteRes, error) {
 		}
 	}
 
-	return nil, nil
+	return DeleteRes{}, nil
 }

pkg/local_object_storage/shard/dump.go

@@ -51,19 +51,19 @@ var ErrMustBeReadOnly = errors.New("shard must be in read-only mode")
 // Dump dumps all objects from the shard to a file or stream.
 //
 // Returns any error encountered.
-func (s *Shard) Dump(prm DumpPrm) (*DumpRes, error) {
+func (s *Shard) Dump(prm DumpPrm) (DumpRes, error) {
 	s.m.RLock()
 	defer s.m.RUnlock()
 
 	if s.info.Mode != ModeReadOnly {
-		return nil, ErrMustBeReadOnly
+		return DumpRes{}, ErrMustBeReadOnly
 	}
 
 	w := prm.stream
 	if w == nil {
 		f, err := os.OpenFile(prm.path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0640)
 		if err != nil {
-			return nil, err
+			return DumpRes{}, err
 		}
 		defer f.Close()
 
@@ -72,7 +72,7 @@ func (s *Shard) Dump(prm DumpPrm) (*DumpRes, error) {
 
 	_, err := w.Write(dumpMagic)
 	if err != nil {
-		return nil, err
+		return DumpRes{}, err
 	}
 
 	var count int
@@ -98,7 +98,7 @@ func (s *Shard) Dump(prm DumpPrm) (*DumpRes, error) {
 
 		err := s.writeCache.Iterate(iterPrm)
 		if err != nil {
-			return nil, err
+			return DumpRes{}, err
 		}
 	}
 
@@ -125,8 +125,8 @@ func (s *Shard) Dump(prm DumpPrm) (*DumpRes, error) {
 	})
 
 	if _, err := s.blobStor.Iterate(pi); err != nil {
-		return nil, err
+		return DumpRes{}, err
 	}
 
-	return &DumpRes{count: count}, nil
+	return DumpRes{count: count}, nil
 }

pkg/local_object_storage/shard/exists.go

@@ -37,7 +37,7 @@ func (p ExistsRes) Exists() bool {
 // unambiguously determine the presence of an object.
 //
 // Returns an error of type apistatus.ObjectAlreadyRemoved if object has been marked as removed.
-func (s *Shard) Exists(prm ExistsPrm) (*ExistsRes, error) {
+func (s *Shard) Exists(prm ExistsPrm) (ExistsRes, error) {
 	exists, err := meta.Exists(s.metaBase, prm.addr)
 	if err != nil {
 		// If the shard is in degraded mode, try to consult blobstor directly.
@@ -57,7 +57,7 @@ func (s *Shard) Exists(prm ExistsPrm) (*ExistsRes, error) {
 		}
 	}
 
-	return &ExistsRes{
+	return ExistsRes{
 		ex: exists,
 	}, err
 }

pkg/local_object_storage/shard/get.go

@@ -47,12 +47,12 @@ func (p *GetPrm) WithIgnoreMeta(ignore bool) {
 }
 
 // Object returns the requested object.
-func (r *GetRes) Object() *objectSDK.Object {
+func (r GetRes) Object() *objectSDK.Object {
 	return r.obj
 }
 
 // HasMeta returns true if info about the object was found in the metabase.
-func (r *GetRes) HasMeta() bool {
+func (r GetRes) HasMeta() bool {
 	return r.hasMeta
 }
 
@@ -63,7 +63,7 @@ func (r *GetRes) HasMeta() bool {
 //
 // Returns an error of type apistatus.ObjectNotFound if the requested object is missing in shard.
 // Returns an error of type apistatus.ObjectAlreadyRemoved if the requested object has been marked as removed in shard.
-func (s *Shard) Get(prm GetPrm) (*GetRes, error) {
+func (s *Shard) Get(prm GetPrm) (GetRes, error) {
 	var big, small storFetcher
 
 	big = func(stor *blobstor.BlobStor, _ *blobovnicza.ID) (*objectSDK.Object, error) {
@@ -93,7 +93,7 @@ func (s *Shard) Get(prm GetPrm) (*GetRes, error) {
 
 	obj, hasMeta, err := s.fetchObjectData(prm.addr, prm.skipMeta, big, small)
 
-	return &GetRes{
+	return GetRes{
 		obj:     obj,
 		hasMeta: hasMeta,
 	}, err

pkg/local_object_storage/shard/get_test.go

@@ -111,7 +111,7 @@ func testShardGet(t *testing.T, hasWriteCache bool) {
 	})
 }
 
-func testGet(t *testing.T, sh *shard.Shard, getPrm shard.GetPrm, hasWriteCache bool) (*shard.GetRes, error) {
+func testGet(t *testing.T, sh *shard.Shard, getPrm shard.GetPrm, hasWriteCache bool) (shard.GetRes, error) {
 	res, err := sh.Get(getPrm)
 	if hasWriteCache {
 		require.Eventually(t, func() bool {

pkg/local_object_storage/shard/head.go

@@ -39,7 +39,7 @@ func (p *HeadPrm) WithRaw(raw bool) {
 }
 
 // Object returns the requested object header.
-func (r *HeadRes) Object() *objectSDK.Object {
+func (r HeadRes) Object() *objectSDK.Object {
 	return r.obj
 }
 
@@ -49,19 +49,19 @@ func (r *HeadRes) Object() *objectSDK.Object {
 //
 // Returns an error of type apistatus.ObjectNotFound if object is missing in Shard.
 // Returns an error of type apistatus.ObjectAlreadyRemoved if the requested object has been marked as removed in shard.
-func (s *Shard) Head(prm HeadPrm) (*HeadRes, error) {
+func (s *Shard) Head(prm HeadPrm) (HeadRes, error) {
 	// object can be saved in write-cache (if enabled) or in metabase
 
 	if s.hasWriteCache() {
 		// try to read header from write-cache
 		header, err := s.writeCache.Head(prm.addr)
 		if err == nil {
-			return &HeadRes{
+			return HeadRes{
 				obj: header,
 			}, nil
 		} else if !writecache.IsErrNotFound(err) {
 			// in this case we think that object is presented in write-cache, but corrupted
-			return nil, fmt.Errorf("could not read header from write-cache: %w", err)
+			return HeadRes{}, fmt.Errorf("could not read header from write-cache: %w", err)
 		}
 
 		// otherwise object seems to be flushed to metabase
@@ -73,10 +73,10 @@ func (s *Shard) Head(prm HeadPrm) (*HeadRes, error) {
 
 	res, err := s.metaBase.Get(headParams)
 	if err != nil {
-		return nil, err
+		return HeadRes{}, err
 	}
 
-	return &HeadRes{
+	return HeadRes{
 		obj: res.Header(),
 	}, nil
 }

pkg/local_object_storage/shard/head_test.go

@@ -80,7 +80,7 @@ func testShardHead(t *testing.T, hasWriteCache bool) {
 	})
 }
 
-func testHead(t *testing.T, sh *shard.Shard, headPrm shard.HeadPrm, hasWriteCache bool) (*shard.HeadRes, error) {
+func testHead(t *testing.T, sh *shard.Shard, headPrm shard.HeadPrm, hasWriteCache bool) (shard.HeadRes, error) {
 	res, err := sh.Head(headPrm)
 	if hasWriteCache {
 		require.Eventually(t, func() bool {

pkg/local_object_storage/shard/inhume.go

@@ -46,9 +46,9 @@ func (p *InhumePrm) MarkAsGarbage(addr ...oid.Address) {
 // if at least one object is locked.
 //
 // Returns ErrReadOnlyMode error if shard is in "read-only" mode.
-func (s *Shard) Inhume(prm InhumePrm) (*InhumeRes, error) {
+func (s *Shard) Inhume(prm InhumePrm) (InhumeRes, error) {
 	if s.GetMode() != ModeReadWrite {
-		return nil, ErrReadOnlyMode
+		return InhumeRes{}, ErrReadOnlyMode
 	}
 
 	if s.hasWriteCache() {
@@ -72,8 +72,8 @@ func (s *Shard) Inhume(prm InhumePrm) (*InhumeRes, error) {
 			zap.String("error", err.Error()),
 		)
 
-		return nil, fmt.Errorf("metabase inhume: %w", err)
+		return InhumeRes{}, fmt.Errorf("metabase inhume: %w", err)
 	}
 
-	return nil, nil
+	return InhumeRes{}, nil
 }

pkg/local_object_storage/shard/list.go

@@ -24,7 +24,7 @@ type ListContainersRes struct {
 	containers []cid.ID
 }
 
-func (r *ListContainersRes) Containers() []cid.ID {
+func (r ListContainersRes) Containers() []cid.ID {
 	return r.containers
 }
 
@@ -63,13 +63,12 @@ func (r ListWithCursorRes) Cursor() *Cursor {
 }
 
 // List returns all objects physically stored in the Shard.
-func (s *Shard) List() (*SelectRes, error) {
+func (s *Shard) List() (res SelectRes, err error) {
 	lst, err := s.metaBase.Containers()
 	if err != nil {
-		return nil, fmt.Errorf("can't list stored containers: %w", err)
+		return res, fmt.Errorf("can't list stored containers: %w", err)
 	}
 
-	res := new(SelectRes)
 	filters := object.NewSearchFilters()
 	filters.AddPhyFilter()
 
@@ -89,13 +88,13 @@ func (s *Shard) List() (*SelectRes, error) {
 	return res, nil
 }
 
-func (s *Shard) ListContainers(_ ListContainersPrm) (*ListContainersRes, error) {
+func (s *Shard) ListContainers(_ ListContainersPrm) (ListContainersRes, error) {
 	containers, err := s.metaBase.Containers()
 	if err != nil {
-		return nil, fmt.Errorf("could not get list of containers: %w", err)
+		return ListContainersRes{}, fmt.Errorf("could not get list of containers: %w", err)
 	}
 
-	return &ListContainersRes{
+	return ListContainersRes{
 		containers: containers,
 	}, nil
 }
@@ -115,16 +114,16 @@ func ListContainers(s *Shard) ([]cid.ID, error) {
 //
 // Returns ErrEndOfListing if there are no more objects to return or count
 // parameter set to zero.
-func (s *Shard) ListWithCursor(prm ListWithCursorPrm) (*ListWithCursorRes, error) {
+func (s *Shard) ListWithCursor(prm ListWithCursorPrm) (ListWithCursorRes, error) {
 	var metaPrm meta.ListPrm
 	metaPrm.WithCount(prm.count)
 	metaPrm.WithCursor(prm.cursor)
 	res, err := s.metaBase.ListWithCursor(metaPrm)
 	if err != nil {
-		return nil, fmt.Errorf("could not get list of objects: %w", err)
+		return ListWithCursorRes{}, fmt.Errorf("could not get list of objects: %w", err)
 	}
 
-	return &ListWithCursorRes{
+	return ListWithCursorRes{
 		addrList: res.AddressList(),
 		cursor:   res.Cursor(),
 	}, nil

pkg/local_object_storage/shard/move.go

@@ -24,9 +24,9 @@ func (p *ToMoveItPrm) WithAddress(addr oid.Address) {
 
 // ToMoveIt calls metabase.ToMoveIt method to mark object as relocatable to
 // another shard.
-func (s *Shard) ToMoveIt(prm ToMoveItPrm) (*ToMoveItRes, error) {
+func (s *Shard) ToMoveIt(prm ToMoveItPrm) (ToMoveItRes, error) {
 	if s.GetMode() != ModeReadWrite {
-		return nil, ErrReadOnlyMode
+		return ToMoveItRes{}, ErrReadOnlyMode
 	}
 
 	err := meta.ToMoveIt(s.metaBase, prm.addr)
@@ -36,5 +36,5 @@ func (s *Shard) ToMoveIt(prm ToMoveItPrm) (*ToMoveItRes, error) {
 		)
 	}
 
-	return new(ToMoveItRes), nil
+	return ToMoveItRes{}, nil
 }

pkg/local_object_storage/shard/put.go

@@ -30,9 +30,9 @@ func (p *PutPrm) WithObject(obj *object.Object) {
 // did not allow to completely save the object.
 //
 // Returns ErrReadOnlyMode error if shard is in "read-only" mode.
-func (s *Shard) Put(prm PutPrm) (*PutRes, error) {
+func (s *Shard) Put(prm PutPrm) (PutRes, error) {
 	if s.GetMode() != ModeReadWrite {
-		return nil, ErrReadOnlyMode
+		return PutRes{}, ErrReadOnlyMode
 	}
 
 	var putPrm blobstor.PutPrm // form Put parameters
@@ -43,7 +43,7 @@ func (s *Shard) Put(prm PutPrm) (*PutRes, error) {
 	if s.hasWriteCache() {
 		err := s.writeCache.Put(prm.obj)
 		if err == nil {
-			return nil, nil
+			return PutRes{}, nil
 		}
 
 		s.log.Debug("can't put message to writeCache, trying to blobStor",
@@ -56,15 +56,15 @@ func (s *Shard) Put(prm PutPrm) (*PutRes, error) {
 	)
 
 	if res, err = s.blobStor.Put(putPrm); err != nil {
-		return nil, fmt.Errorf("could not put object to BLOB storage: %w", err)
+		return PutRes{}, fmt.Errorf("could not put object to BLOB storage: %w", err)
 	}
 
 	// put to metabase
 	if err := meta.Put(s.metaBase, prm.obj, res.BlobovniczaID()); err != nil {
 		// may we need to handle this case in a special way
 		// since the object has been successfully written to BlobStor
-		return nil, fmt.Errorf("could not put object to metabase: %w", err)
+		return PutRes{}, fmt.Errorf("could not put object to metabase: %w", err)
 	}
 
-	return nil, nil
+	return PutRes{}, nil
 }

pkg/local_object_storage/shard/range.go

@@ -66,7 +66,7 @@ func (r RngRes) HasMeta() bool {
 // Returns ErrRangeOutOfBounds if the requested object range is out of bounds.
 // Returns an error of type apistatus.ObjectNotFound if the requested object is missing.
 // Returns an error of type apistatus.ObjectAlreadyRemoved if the requested object has been marked as removed in shard.
-func (s *Shard) GetRange(prm RngPrm) (*RngRes, error) {
+func (s *Shard) GetRange(prm RngPrm) (RngRes, error) {
 	var big, small storFetcher
 
 	rng := object.NewRange()
@@ -108,7 +108,7 @@ func (s *Shard) GetRange(prm RngPrm) (*RngRes, error) {
 
 	obj, hasMeta, err := s.fetchObjectData(prm.addr, prm.skipMeta, big, small)
 
-	return &RngRes{
+	return RngRes{
 		obj:     obj,
 		hasMeta: hasMeta,
 	}, err

pkg/local_object_storage/shard/restore.go

@@ -56,20 +56,20 @@ func (r RestoreRes) FailCount() int {
 // Restore restores objects from the dump prepared by Dump.
 //
 // Returns any error encountered.
-func (s *Shard) Restore(prm RestorePrm) (*RestoreRes, error) {
+func (s *Shard) Restore(prm RestorePrm) (RestoreRes, error) {
 	// Disallow changing mode during restore.
 	s.m.RLock()
 	defer s.m.RUnlock()
 
 	if s.info.Mode != ModeReadWrite {
-		return nil, ErrReadOnlyMode
+		return RestoreRes{}, ErrReadOnlyMode
 	}
 
 	r := prm.stream
 	if r == nil {
 		f, err := os.OpenFile(prm.path, os.O_RDONLY, os.ModeExclusive)
 		if err != nil {
-			return nil, err
+			return RestoreRes{}, err
 		}
 		defer f.Close()
 
@@ -79,7 +79,7 @@ func (s *Shard) Restore(prm RestorePrm) (*RestoreRes, error) {
 	var m [4]byte
 	_, _ = io.ReadFull(r, m[:])
 	if !bytes.Equal(m[:], dumpMagic) {
-		return nil, ErrInvalidMagic
+		return RestoreRes{}, ErrInvalidMagic
 	}
 
 	var putPrm PutPrm
@@ -95,7 +95,7 @@ func (s *Shard) Restore(prm RestorePrm) (*RestoreRes, error) {
 			if errors.Is(err, io.EOF) {
 				break
 			}
-			return nil, err
+			return RestoreRes{}, err
 		}
 
 		sz := binary.LittleEndian.Uint32(size[:])
@@ -107,7 +107,7 @@ func (s *Shard) Restore(prm RestorePrm) (*RestoreRes, error) {
 
 		_, err = r.Read(data)
 		if err != nil {
-			return nil, err
+			return RestoreRes{}, err
 		}
 
 		obj := object.New()
@@ -117,17 +117,17 @@ func (s *Shard) Restore(prm RestorePrm) (*RestoreRes, error) {
 				failCount++
 				continue
 			}
-			return nil, err
+			return RestoreRes{}, err
 		}
 
 		putPrm.WithObject(obj)
 		_, err = s.Put(putPrm)
 		if err != nil {
-			return nil, err
+			return RestoreRes{}, err
 		}
 
 		count++
 	}
 
-	return &RestoreRes{count: count, failed: failCount}, nil
+	return RestoreRes{count: count, failed: failCount}, nil
 }

pkg/local_object_storage/shard/select.go

@@ -43,13 +43,13 @@ func (r SelectRes) AddressList() []oid.Address {
 //
 // Returns any error encountered that
 // did not allow to completely select the objects.
-func (s *Shard) Select(prm SelectPrm) (*SelectRes, error) {
+func (s *Shard) Select(prm SelectPrm) (SelectRes, error) {
 	addrList, err := meta.Select(s.metaBase, prm.cnr, prm.filters)
 	if err != nil {
-		return nil, fmt.Errorf("could not select objects from metabase: %w", err)
+		return SelectRes{}, fmt.Errorf("could not select objects from metabase: %w", err)
 	}
 
-	return &SelectRes{
+	return SelectRes{
 		addrList: addrList,
 	}, nil
 }