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

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

pkg/local_object_storage/blobstor/blobovnicza.go

@@ -205,7 +205,7 @@ func (b *blobovniczas) put(addr oid.Address, data []byte) (*blobovnicza.ID, erro
 //
 // If blobocvnicza ID is specified, only this blobovnicza is processed.
 // Otherwise, all blobovniczas are processed descending weight.
-func (b *blobovniczas) get(prm GetSmallPrm) (res *GetSmallRes, err error) {
+func (b *blobovniczas) get(prm GetSmallPrm) (res GetSmallRes, err error) {
 	var bPrm blobovnicza.GetPrm
 	bPrm.SetAddress(prm.addr)
 
@@ -241,7 +241,7 @@ func (b *blobovniczas) get(prm GetSmallPrm) (res *GetSmallRes, err error) {
 		return err == nil, nil
 	})
 
-	if err == nil && res == nil {
+	if err == nil && res.Object() == nil {
 		// not found in any blobovnicza
 		var errNotFound apistatus.ObjectNotFound
 
@@ -255,7 +255,7 @@ func (b *blobovniczas) get(prm GetSmallPrm) (res *GetSmallRes, err error) {
 //
 // If blobocvnicza ID is specified, only this blobovnicza is processed.
 // Otherwise, all blobovniczas are processed descending weight.
-func (b *blobovniczas) delete(prm DeleteSmallPrm) (res *DeleteSmallRes, err error) {
+func (b *blobovniczas) delete(prm DeleteSmallPrm) (res DeleteSmallRes, err error) {
 	var bPrm blobovnicza.DeletePrm
 	bPrm.SetAddress(prm.addr)
 
@@ -301,7 +301,7 @@ func (b *blobovniczas) delete(prm DeleteSmallPrm) (res *DeleteSmallRes, err erro
 		// not found in any blobovnicza
 		var errNotFound apistatus.ObjectNotFound
 
-		return nil, errNotFound
+		return DeleteSmallRes{}, errNotFound
 	}
 
 	return
@@ -311,11 +311,11 @@ func (b *blobovniczas) delete(prm DeleteSmallPrm) (res *DeleteSmallRes, err erro
 //
 // If blobocvnicza ID is specified, only this blobovnicza is processed.
 // Otherwise, all blobovniczas are processed descending weight.
-func (b *blobovniczas) getRange(prm GetRangeSmallPrm) (res *GetRangeSmallRes, err error) {
+func (b *blobovniczas) getRange(prm GetRangeSmallPrm) (res GetRangeSmallRes, err error) {
 	if prm.blobovniczaID != nil {
 		blz, err := b.openBlobovnicza(prm.blobovniczaID.String())
 		if err != nil {
-			return nil, err
+			return GetRangeSmallRes{}, err
 		}
 
 		return b.getObjectRange(blz, prm)
@@ -355,7 +355,7 @@ func (b *blobovniczas) getRange(prm GetRangeSmallPrm) (res *GetRangeSmallRes, er
 		// not found in any blobovnicza
 		var errNotFound apistatus.ObjectNotFound
 
-		return nil, errNotFound
+		return GetRangeSmallRes{}, errNotFound
 	}
 
 	return
@@ -364,7 +364,7 @@ func (b *blobovniczas) getRange(prm GetRangeSmallPrm) (res *GetRangeSmallRes, er
 // tries to delete object from particular blobovnicza.
 //
 // returns no error if object was removed from some blobovnicza of the same level.
-func (b *blobovniczas) deleteObjectFromLevel(prm blobovnicza.DeletePrm, blzPath string, tryActive bool, dp DeleteSmallPrm) (*DeleteSmallRes, error) {
+func (b *blobovniczas) deleteObjectFromLevel(prm blobovnicza.DeletePrm, blzPath string, tryActive bool, dp DeleteSmallPrm) (DeleteSmallRes, error) {
 	lvlPath := filepath.Dir(blzPath)
 
 	// try to remove from blobovnicza if it is opened
@@ -410,13 +410,13 @@ func (b *blobovniczas) deleteObjectFromLevel(prm blobovnicza.DeletePrm, blzPath
 		b.log.Debug("index is too big", zap.String("path", blzPath))
 		var errNotFound apistatus.ObjectNotFound
 
-		return nil, errNotFound
+		return DeleteSmallRes{}, errNotFound
 	}
 
 	// open blobovnicza (cached inside)
 	blz, err := b.openBlobovnicza(blzPath)
 	if err != nil {
-		return nil, err
+		return DeleteSmallRes{}, err
 	}
 
 	return b.deleteObject(blz, prm, dp)
@@ -425,7 +425,7 @@ func (b *blobovniczas) deleteObjectFromLevel(prm blobovnicza.DeletePrm, blzPath
 // tries to read object from particular blobovnicza.
 //
 // returns error if object could not be read from any blobovnicza of the same level.
-func (b *blobovniczas) getObjectFromLevel(prm blobovnicza.GetPrm, blzPath string, tryActive bool) (*GetSmallRes, error) {
+func (b *blobovniczas) getObjectFromLevel(prm blobovnicza.GetPrm, blzPath string, tryActive bool) (GetSmallRes, error) {
 	lvlPath := filepath.Dir(blzPath)
 
 	// try to read from blobovnicza if it is opened
@@ -472,13 +472,13 @@ func (b *blobovniczas) getObjectFromLevel(prm blobovnicza.GetPrm, blzPath string
 		b.log.Debug("index is too big", zap.String("path", blzPath))
 		var errNotFound apistatus.ObjectNotFound
 
-		return nil, errNotFound
+		return GetSmallRes{}, errNotFound
 	}
 
 	// open blobovnicza (cached inside)
 	blz, err := b.openBlobovnicza(blzPath)
 	if err != nil {
-		return nil, err
+		return GetSmallRes{}, err
 	}
 
 	return b.getObject(blz, prm)
@@ -487,7 +487,7 @@ func (b *blobovniczas) getObjectFromLevel(prm blobovnicza.GetPrm, blzPath string
 // tries to read range of object payload data from particular blobovnicza.
 //
 // returns error if object could not be read from any blobovnicza of the same level.
-func (b *blobovniczas) getRangeFromLevel(prm GetRangeSmallPrm, blzPath string, tryActive bool) (*GetRangeSmallRes, error) {
+func (b *blobovniczas) getRangeFromLevel(prm GetRangeSmallPrm, blzPath string, tryActive bool) (GetRangeSmallRes, error) {
 	lvlPath := filepath.Dir(blzPath)
 
 	// try to read from blobovnicza if it is opened
@@ -545,23 +545,23 @@ func (b *blobovniczas) getRangeFromLevel(prm GetRangeSmallPrm, blzPath string, t
 
 		var errNotFound apistatus.ObjectNotFound
 
-		return nil, errNotFound
+		return GetRangeSmallRes{}, errNotFound
 	}
 
 	// open blobovnicza (cached inside)
 	blz, err := b.openBlobovnicza(blzPath)
 	if err != nil {
-		return nil, err
+		return GetRangeSmallRes{}, err
 	}
 
 	return b.getObjectRange(blz, prm)
 }
 
 // removes object from blobovnicza and returns DeleteSmallRes.
-func (b *blobovniczas) deleteObject(blz *blobovnicza.Blobovnicza, prm blobovnicza.DeletePrm, dp DeleteSmallPrm) (*DeleteSmallRes, error) {
+func (b *blobovniczas) deleteObject(blz *blobovnicza.Blobovnicza, prm blobovnicza.DeletePrm, dp DeleteSmallPrm) (DeleteSmallRes, error) {
 	_, err := blz.Delete(prm)
 	if err != nil {
-		return nil, err
+		return DeleteSmallRes{}, err
 	}
 
 	storagelog.Write(b.log,
@@ -570,29 +570,29 @@ func (b *blobovniczas) deleteObject(blz *blobovnicza.Blobovnicza, prm blobovnicz
 		zap.Stringer("blobovnicza ID", dp.blobovniczaID),
 	)
 
-	return nil, nil
+	return DeleteSmallRes{}, nil
 }
 
 // reads object from blobovnicza and returns GetSmallRes.
-func (b *blobovniczas) getObject(blz *blobovnicza.Blobovnicza, prm blobovnicza.GetPrm) (*GetSmallRes, error) {
+func (b *blobovniczas) getObject(blz *blobovnicza.Blobovnicza, prm blobovnicza.GetPrm) (GetSmallRes, error) {
 	res, err := blz.Get(prm)
 	if err != nil {
-		return nil, err
+		return GetSmallRes{}, err
 	}
 
 	// decompress the data
 	data, err := b.decompressor(res.Object())
 	if err != nil {
-		return nil, fmt.Errorf("could not decompress object data: %w", err)
+		return GetSmallRes{}, fmt.Errorf("could not decompress object data: %w", err)
 	}
 
 	// unmarshal the object
 	obj := objectSDK.New()
 	if err := obj.Unmarshal(data); err != nil {
-		return nil, fmt.Errorf("could not unmarshal the object: %w", err)
+		return GetSmallRes{}, fmt.Errorf("could not unmarshal the object: %w", err)
 	}
 
-	return &GetSmallRes{
+	return GetSmallRes{
 		roObject: roObject{
 			obj: obj,
 		},
@@ -600,7 +600,7 @@ func (b *blobovniczas) getObject(blz *blobovnicza.Blobovnicza, prm blobovnicza.G
 }
 
 // reads range of object payload data from blobovnicza and returns GetRangeSmallRes.
-func (b *blobovniczas) getObjectRange(blz *blobovnicza.Blobovnicza, prm GetRangeSmallPrm) (*GetRangeSmallRes, error) {
+func (b *blobovniczas) getObjectRange(blz *blobovnicza.Blobovnicza, prm GetRangeSmallPrm) (GetRangeSmallRes, error) {
 	var gPrm blobovnicza.GetPrm
 	gPrm.SetAddress(prm.addr)
 
@@ -610,19 +610,19 @@ func (b *blobovniczas) getObjectRange(blz *blobovnicza.Blobovnicza, prm GetRange
 	// we can start using GetRange.
 	res, err := blz.Get(gPrm)
 	if err != nil {
-		return nil, err
+		return GetRangeSmallRes{}, err
 	}
 
 	// decompress the data
 	data, err := b.decompressor(res.Object())
 	if err != nil {
-		return nil, fmt.Errorf("could not decompress object data: %w", err)
+		return GetRangeSmallRes{}, fmt.Errorf("could not decompress object data: %w", err)
 	}
 
 	// unmarshal the object
 	obj := objectSDK.New()
 	if err := obj.Unmarshal(data); err != nil {
-		return nil, fmt.Errorf("could not unmarshal the object: %w", err)
+		return GetRangeSmallRes{}, fmt.Errorf("could not unmarshal the object: %w", err)
 	}
 
 	from := prm.rng.GetOffset()
@@ -630,10 +630,10 @@ func (b *blobovniczas) getObjectRange(blz *blobovnicza.Blobovnicza, prm GetRange
 	payload := obj.Payload()
 
 	if uint64(len(payload)) < to {
-		return nil, object.ErrRangeOutOfBounds
+		return GetRangeSmallRes{}, object.ErrRangeOutOfBounds
 	}
 
-	return &GetRangeSmallRes{
+	return GetRangeSmallRes{
 		rangeData: rangeData{
 			data: payload[from:to],
 		},

pkg/local_object_storage/blobstor/delete_big.go

@@ -22,7 +22,7 @@ type DeleteBigRes struct{}
 // to completely remove the object.
 //
 // Returns an error of type apistatus.ObjectNotFound if there is no object to delete.
-func (b *BlobStor) DeleteBig(prm DeleteBigPrm) (*DeleteBigRes, error) {
+func (b *BlobStor) DeleteBig(prm DeleteBigPrm) (DeleteBigRes, error) {
 	err := b.fsTree.Delete(prm.addr)
 	if errors.Is(err, fstree.ErrFileNotFound) {
 		var errNotFound apistatus.ObjectNotFound
@@ -34,5 +34,5 @@ func (b *BlobStor) DeleteBig(prm DeleteBigPrm) (*DeleteBigRes, error) {
 		storagelog.Write(b.log, storagelog.AddressField(prm.addr), storagelog.OpField("fstree DELETE"))
 	}
 
-	return nil, err
+	return DeleteBigRes{}, err
 }

pkg/local_object_storage/blobstor/delete_small.go

@@ -18,6 +18,6 @@ type DeleteSmallRes struct{}
 // to completely remove the object.
 //
 // Returns an error of type apistatus.ObjectNotFound if there is no object to delete.
-func (b *BlobStor) DeleteSmall(prm DeleteSmallPrm) (*DeleteSmallRes, error) {
+func (b *BlobStor) DeleteSmall(prm DeleteSmallPrm) (DeleteSmallRes, error) {
 	return b.blobovniczas.delete(prm)
 }

pkg/local_object_storage/blobstor/exists.go

@@ -29,7 +29,7 @@ func (r ExistsRes) Exists() bool {
 //
 // Returns any error encountered that did not allow
 // to completely check object existence.
-func (b *BlobStor) Exists(prm ExistsPrm) (*ExistsRes, error) {
+func (b *BlobStor) Exists(prm ExistsPrm) (ExistsRes, error) {
 	// check presence in shallow dir first (cheaper)
 	exists, err := b.existsBig(prm.addr)
 
@@ -58,9 +58,10 @@ func (b *BlobStor) Exists(prm ExistsPrm) (*ExistsRes, error) {
 	}
 
 	if err != nil {
-		return nil, err
+		return ExistsRes{}, err
 	}
-	return &ExistsRes{exists: exists}, err
+
+	return ExistsRes{exists: exists}, err
 }
 
 // checks if object is presented in shallow dir.

pkg/local_object_storage/blobstor/get_big.go

@@ -26,31 +26,31 @@ type GetBigRes struct {
 //
 // Returns an error of type apistatus.ObjectNotFound if the requested object is not
 // presented in shallow dir.
-func (b *BlobStor) GetBig(prm GetBigPrm) (*GetBigRes, error) {
+func (b *BlobStor) GetBig(prm GetBigPrm) (GetBigRes, error) {
 	// get compressed object data
 	data, err := b.fsTree.Get(prm.addr)
 	if err != nil {
 		if errors.Is(err, fstree.ErrFileNotFound) {
 			var errNotFound apistatus.ObjectNotFound
 
-			return nil, errNotFound
+			return GetBigRes{}, errNotFound
 		}
 
-		return nil, fmt.Errorf("could not read object from fs tree: %w", err)
+		return GetBigRes{}, fmt.Errorf("could not read object from fs tree: %w", err)
 	}
 
 	data, err = b.decompressor(data)
 	if err != nil {
-		return nil, fmt.Errorf("could not decompress object data: %w", err)
+		return GetBigRes{}, fmt.Errorf("could not decompress object data: %w", err)
 	}
 
 	// unmarshal the object
 	obj := objectSDK.New()
 	if err := obj.Unmarshal(data); err != nil {
-		return nil, fmt.Errorf("could not unmarshal the object: %w", err)
+		return GetBigRes{}, fmt.Errorf("could not unmarshal the object: %w", err)
 	}
 
-	return &GetBigRes{
+	return GetBigRes{
 		roObject: roObject{
 			obj: obj,
 		},

pkg/local_object_storage/blobstor/get_range_big.go

@@ -28,38 +28,38 @@ type GetRangeBigRes struct {
 //
 // Returns ErrRangeOutOfBounds if the requested object range is out of bounds.
 // Returns an error of type apistatus.ObjectNotFound if object is missing.
-func (b *BlobStor) GetRangeBig(prm GetRangeBigPrm) (*GetRangeBigRes, error) {
+func (b *BlobStor) GetRangeBig(prm GetRangeBigPrm) (GetRangeBigRes, error) {
 	// get compressed object data
 	data, err := b.fsTree.Get(prm.addr)
 	if err != nil {
 		if errors.Is(err, fstree.ErrFileNotFound) {
 			var errNotFound apistatus.ObjectNotFound
 
-			return nil, errNotFound
+			return GetRangeBigRes{}, errNotFound
 		}
 
-		return nil, fmt.Errorf("could not read object from fs tree: %w", err)
+		return GetRangeBigRes{}, fmt.Errorf("could not read object from fs tree: %w", err)
 	}
 
 	data, err = b.decompressor(data)
 	if err != nil {
-		return nil, fmt.Errorf("could not decompress object data: %w", err)
+		return GetRangeBigRes{}, fmt.Errorf("could not decompress object data: %w", err)
 	}
 
 	// unmarshal the object
 	obj := objectSDK.New()
 	if err := obj.Unmarshal(data); err != nil {
-		return nil, fmt.Errorf("could not unmarshal the object: %w", err)
+		return GetRangeBigRes{}, fmt.Errorf("could not unmarshal the object: %w", err)
 	}
 
 	payload := obj.Payload()
 	ln, off := prm.rng.GetLength(), prm.rng.GetOffset()
 
 	if pLen := uint64(len(payload)); pLen < ln+off {
-		return nil, object.ErrRangeOutOfBounds
+		return GetRangeBigRes{}, object.ErrRangeOutOfBounds
 	}
 
-	return &GetRangeBigRes{
+	return GetRangeBigRes{
 		rangeData: rangeData{
 			data: payload[off : off+ln],
 		},

pkg/local_object_storage/blobstor/get_range_small.go

@@ -22,6 +22,6 @@ type GetRangeSmallRes struct {
 //
 // Returns ErrRangeOutOfBounds if the requested object range is out of bounds.
 // Returns an error of type apistatus.ObjectNotFound if the requested object is missing in blobovnicza(s).
-func (b *BlobStor) GetRangeSmall(prm GetRangeSmallPrm) (*GetRangeSmallRes, error) {
+func (b *BlobStor) GetRangeSmall(prm GetRangeSmallPrm) (GetRangeSmallRes, error) {
 	return b.blobovniczas.getRange(prm)
 }

pkg/local_object_storage/blobstor/get_small.go

@@ -20,6 +20,6 @@ type GetSmallRes struct {
 // did not allow to completely read the object.
 //
 // Returns an error of type apistatus.ObjectNotFound if the requested object is missing in blobovnicza(s).
-func (b *BlobStor) GetSmall(prm GetSmallPrm) (*GetSmallRes, error) {
+func (b *BlobStor) GetSmall(prm GetSmallPrm) (GetSmallRes, error) {
 	return b.blobovniczas.get(prm)
 }

pkg/local_object_storage/blobstor/iterate.go

@@ -56,7 +56,7 @@ func (i *IteratePrm) IgnoreErrors() {
 // did not allow to completely iterate over the storage.
 //
 // If handler returns an error, method wraps and returns it immediately.
-func (b *BlobStor) Iterate(prm IteratePrm) (*IterateRes, error) {
+func (b *BlobStor) Iterate(prm IteratePrm) (IterateRes, error) {
 	var elem IterationElement
 
 	err := b.blobovniczas.iterateBlobovniczas(prm.ignoreErrors, func(p string, blz *blobovnicza.Blobovnicza) error {
@@ -83,7 +83,7 @@ func (b *BlobStor) Iterate(prm IteratePrm) (*IterateRes, error) {
 		return nil
 	})
 	if err != nil {
-		return nil, fmt.Errorf("blobovniczas iterator failure: %w", err)
+		return IterateRes{}, fmt.Errorf("blobovniczas iterator failure: %w", err)
 	}
 
 	elem.blzID = nil
@@ -106,10 +106,10 @@ func (b *BlobStor) Iterate(prm IteratePrm) (*IterateRes, error) {
 	err = b.fsTree.Iterate(fsPrm)
 
 	if err != nil {
-		return nil, fmt.Errorf("fs tree iterator failure: %w", err)
+		return IterateRes{}, fmt.Errorf("fs tree iterator failure: %w", err)
 	}
 
-	return new(IterateRes), nil
+	return IterateRes{}, nil
 }
 
 // IterateBinaryObjects is a helper function which iterates over BlobStor and passes binary objects to f.

pkg/local_object_storage/blobstor/put.go

@@ -30,11 +30,11 @@ type PutRes struct {
 //
 // Returns any error encountered that
 // did not allow to completely save the object.
-func (b *BlobStor) Put(prm PutPrm) (*PutRes, error) {
+func (b *BlobStor) Put(prm PutPrm) (PutRes, error) {
 	// marshal object
 	data, err := prm.obj.Marshal()
 	if err != nil {
-		return nil, fmt.Errorf("could not marshal the object: %w", err)
+		return PutRes{}, fmt.Errorf("could not marshal the object: %w", err)
 	}
 
 	return b.PutRaw(object.AddressOf(prm.obj), data, b.NeedsCompression(prm.obj))
@@ -72,7 +72,7 @@ func (b *BlobStor) NeedsCompression(obj *objectSDK.Object) bool {
 }
 
 // PutRaw saves an already marshaled object in BLOB storage.
-func (b *BlobStor) PutRaw(addr oid.Address, data []byte, compress bool) (*PutRes, error) {
+func (b *BlobStor) PutRaw(addr oid.Address, data []byte, compress bool) (PutRes, error) {
 	big := b.isBig(data)
 
 	if big {
@@ -89,12 +89,12 @@ func (b *BlobStor) PutRaw(addr oid.Address, data []byte, compress bool) (*PutRes
 			err = b.fsTree.Put(addr, data)
 		}
 		if err != nil {
-			return nil, err
+			return PutRes{}, err
 		}
 
 		storagelog.Write(b.log, storagelog.AddressField(addr), storagelog.OpField("fstree PUT"))
 
-		return new(PutRes), nil
+		return PutRes{}, nil
 	}
 
 	if compress {
@@ -104,10 +104,10 @@ func (b *BlobStor) PutRaw(addr oid.Address, data []byte, compress bool) (*PutRes
 	// save object in blobovnicza
 	res, err := b.blobovniczas.put(addr, data)
 	if err != nil {
-		return nil, err
+		return PutRes{}, err
 	}
 
-	return &PutRes{
+	return PutRes{
 		roBlobovniczaID: roBlobovniczaID{
 			blobovniczaID: res,
 		},

pkg/local_object_storage/shard/put.go

@@ -52,7 +52,7 @@ func (s *Shard) Put(prm PutPrm) (PutRes, error) {
 
 	var (
 		err error
-		res *blobstor.PutRes
+		res blobstor.PutRes
 	)
 
 	if res, err = s.blobStor.Put(putPrm); err != nil {