[#64] transformer: Simplify interface

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

client/object_put_transformer.go

@@ -21,7 +21,7 @@ func (c *Client) objectPutInitTransformer(prm PrmObjectPutInit) (*objectWriterTr
 	}
 	w.ot = transformer.NewPayloadSizeLimiter(transformer.Params{
 		Key:                    key,
-		NextTargetInit:         func() transformer.ObjectTarget { return &w.it },
+		NextTargetInit:         func() transformer.ObjectWriter { return &w.it },
 		MaxSize:                prm.maxSize,
 		WithoutHomomorphicHash: prm.withoutHomomorphicHash,
 		NetworkState:           prm.epochSource,
@@ -30,7 +30,7 @@ func (c *Client) objectPutInitTransformer(prm PrmObjectPutInit) (*objectWriterTr
 }
 
 type objectWriterTransformer struct {
-	ot  transformer.ObjectTarget
+	ot  transformer.ChunkedObjectWriter
 	it  internalTarget
 	err error
 }
@@ -58,56 +58,40 @@ func (x *objectWriterTransformer) Close(ctx context.Context) (*ResObjectPut, err
 }
 
 type internalTarget struct {
-	current   *object.Object
 	client    *Client
 	res       *ResObjectPut
 	prm       PrmObjectPutInit
-	payload   []byte
 	useStream bool
 }
 
-func (it *internalTarget) WriteHeader(_ context.Context, object *object.Object) error {
-	it.current = object
-	return nil
-}
-
-func (it *internalTarget) Write(_ context.Context, p []byte) (n int, err error) {
-	it.payload = append(it.payload, p...)
-	return len(p), nil
-}
-
-func (it *internalTarget) Close(ctx context.Context) (*transformer.AccessIdentifiers, error) {
-	it.current.SetPayload(it.payload)
-
-	putSingleImplemented, err := it.tryPutSingle(ctx)
+func (it *internalTarget) WriteObject(ctx context.Context, o *object.Object) error {
+	putSingleImplemented, err := it.tryPutSingle(ctx, o)
 	if putSingleImplemented {
-		return nil, err
+		return err
 	}
 	it.useStream = true
-	return nil, it.putAsStream(ctx)
+	return it.putAsStream(ctx, o)
 }
 
-func (it *internalTarget) putAsStream(ctx context.Context) error {
+func (it *internalTarget) putAsStream(ctx context.Context, o *object.Object) error {
 	wrt, err := it.client.objectPutInitRaw(ctx, it.prm)
 	if err != nil {
 		return err
 	}
-	if wrt.WriteHeader(ctx, *it.current) {
-		wrt.WritePayloadChunk(ctx, it.current.Payload())
+	if wrt.WriteHeader(ctx, *o) {
+		wrt.WritePayloadChunk(ctx, o.Payload())
 	}
 	it.res, err = wrt.Close(ctx)
-	it.current = nil
-	it.payload = nil
 	return err
 }
 
-func (it *internalTarget) tryPutSingle(ctx context.Context) (bool, error) {
+func (it *internalTarget) tryPutSingle(ctx context.Context, o *object.Object) (bool, error) {
 	if it.useStream {
 		return false, nil
 	}
 	var prm PrmObjectPutSingle
 	prm.SetCopiesNumber(it.prm.copyNum)
-	prm.SetObject(it.current.ToV2())
+	prm.SetObject(o.ToV2())
 	prm.UseKey(prm.key)
 	prm.meta = it.prm.meta
 
@@ -117,13 +101,11 @@ func (it *internalTarget) tryPutSingle(ctx context.Context) (bool, error) {
 	}
 
 	if err == nil {
-		id, _ := it.current.ID()
+		id, _ := o.ID()
 		it.res = &ResObjectPut{
 			statusRes: res.statusRes,
 			obj:       id,
 		}
 	}
-	it.current = nil
-	it.payload = nil
 	return true, err
 }

object/transformer/channel.go

@@ -4,47 +4,25 @@ import (
 	"context"
 
 	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
-	"github.com/nspcc-dev/neo-go/pkg/util/slice"
 )
 
 type chanTarget struct {
-	header  *objectSDK.Object
-	payload []byte
-	ch      chan<- *objectSDK.Object
+	ch chan<- *objectSDK.Object
 }
 
 // NewChannelTarget returns ObjectTarget which writes
 // object parts to a provided channel.
-func NewChannelTarget(ch chan<- *objectSDK.Object) ObjectTarget {
+func NewChannelTarget(ch chan<- *objectSDK.Object) ObjectWriter {
 	return &chanTarget{
 		ch: ch,
 	}
 }
 
-// WriteHeader implements the ObjectTarget interface.
-func (c *chanTarget) WriteHeader(_ context.Context, object *objectSDK.Object) error {
-	c.header = object
+func (c *chanTarget) WriteObject(ctx context.Context, o *objectSDK.Object) error {
+	select {
+	case c.ch <- o:
+	case <-ctx.Done():
+		return ctx.Err()
+	}
 	return nil
 }
-
-// Write implements the ObjectTarget interface.
-func (c *chanTarget) Write(_ context.Context, p []byte) (n int, err error) {
-	c.payload = append(c.payload, p...)
-	return len(p), nil
-}
-
-// Close implements the ObjectTarget interface.
-func (c *chanTarget) Close(ctx context.Context) (*AccessIdentifiers, error) {
-	if len(c.payload) != 0 {
-		c.header.SetPayload(slice.Copy(c.payload))
-	}
-	select {
-	case c.ch <- c.header:
-	case <-ctx.Done():
-		return nil, ctx.Err()
-	}
-
-	c.header = nil
-	c.payload = nil
-	return new(AccessIdentifiers), nil
-}

object/transformer/channel_test.go

@@ -18,8 +18,8 @@ func TestChannelTarget(t *testing.T) {
 	tt := new(testTarget)
 	ct := NewChannelTarget(ch)
 
-	chTarget, _ := newPayloadSizeLimiter(maxSize, func() ObjectTarget { return ct })
-	testTarget, _ := newPayloadSizeLimiter(maxSize, func() ObjectTarget { return tt })
+	chTarget, _ := newPayloadSizeLimiter(maxSize, func() ObjectWriter { return ct })
+	testTarget, _ := newPayloadSizeLimiter(maxSize, func() ObjectWriter { return tt })
 
 	ver := version.Current()
 	cnr := cidtest.ID()

object/transformer/transformer.go

@@ -20,6 +20,7 @@ type payloadSizeLimiter struct {
 	written, writtenCurrent uint64
 
 	current, parent *object.Object
+	payload         []byte
 
 	currentHashers, parentHashers []payloadChecksumHasher
 
@@ -29,12 +30,12 @@ type payloadSizeLimiter struct {
 
 	parAttrs []object.Attribute
 
-	nextTarget ObjectTarget
+	nextTarget ObjectWriter
 }
 
 type Params struct {
 	Key                    *ecdsa.PrivateKey
-	NextTargetInit         func() ObjectTarget
+	NextTargetInit         TargetInitializer
 	SessionToken           *session.Object
 	NetworkState           EpochSource
 	MaxSize                uint64
@@ -48,7 +49,7 @@ type Params struct {
 // is false.
 //
 // Objects w/ payload size less or equal than max size remain untouched.
-func NewPayloadSizeLimiter(p Params) ObjectTarget {
+func NewPayloadSizeLimiter(p Params) ChunkedObjectWriter {
 	return &payloadSizeLimiter{
 		Params:  p,
 		splitID: object.NewSplitID(),
@@ -120,6 +121,7 @@ func (s *payloadSizeLimiter) initializeCurrent() {
 	s.nextTarget = s.NextTargetInit()
 	s.writtenCurrent = 0
 	s.initPayloadHashers()
+	s.payload = make([]byte, 0)
 }
 
 func (s *payloadSizeLimiter) initPayloadHashers() {
@@ -160,12 +162,9 @@ func (s *payloadSizeLimiter) release(ctx context.Context, finalize bool) (*Acces
 		return nil, fmt.Errorf("fillHeader: %w", err)
 	}
 
-	if err := s.nextTarget.WriteHeader(ctx, s.current); err != nil {
-		return nil, fmt.Errorf("could not write header to next target: %w", err)
-	}
-
-	if _, err := s.nextTarget.Close(ctx); err != nil {
-		return nil, fmt.Errorf("could not close next target: %w", err)
+	s.current.SetPayload(s.payload)
+	if err := s.nextTarget.WriteObject(ctx, s.current); err != nil {
+		return nil, fmt.Errorf("could not write to next target: %w", err)
 	}
 
 	// save identifier of the released object
@@ -262,7 +261,7 @@ func (s *payloadSizeLimiter) writeChunk(ctx context.Context, chunk []byte) error
 			cut = leftToEdge
 		}
 
-		if err := s.writeHashes(ctx, chunk[:cut]); err != nil {
+		if err := s.writeHashes(chunk[:cut]); err != nil {
 			return fmt.Errorf("could not write chunk to target: %w", err)
 		}
 
@@ -278,11 +277,8 @@ func (s *payloadSizeLimiter) writeChunk(ctx context.Context, chunk []byte) error
 	}
 }
 
-func (s *payloadSizeLimiter) writeHashes(ctx context.Context, chunk []byte) error {
-	_, err := s.nextTarget.Write(ctx, chunk)
-	if err != nil {
-		return err
-	}
+func (s *payloadSizeLimiter) writeHashes(chunk []byte) error {
+	s.payload = append(s.payload, chunk...)
 
 	// The `Write` method of `hash.Hash` never returns an error.
 	for i := range s.currentHashers {

object/transformer/transformer_test.go

@@ -20,7 +20,7 @@ func TestTransformer(t *testing.T) {
 
 	tt := new(testTarget)
 
-	target, pk := newPayloadSizeLimiter(maxSize, func() ObjectTarget { return tt })
+	target, pk := newPayloadSizeLimiter(maxSize, func() ObjectWriter { return tt })
 
 	cnr := cidtest.ID()
 	hdr := newObject(cnr)
@@ -99,7 +99,7 @@ func newObject(cnr cid.ID) *objectSDK.Object {
 	return hdr
 }
 
-func writeObject(t *testing.T, ctx context.Context, target ObjectTarget, header *objectSDK.Object, payload []byte) *AccessIdentifiers {
+func writeObject(t *testing.T, ctx context.Context, target ChunkedObjectWriter, header *objectSDK.Object, payload []byte) *AccessIdentifiers {
 	require.NoError(t, target.WriteHeader(ctx, header))
 
 	_, err := target.Write(ctx, payload)
@@ -131,7 +131,7 @@ func benchmarkTransformer(b *testing.B, header *objectSDK.Object, payloadSize in
 	b.ReportAllocs()
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		f, _ := newPayloadSizeLimiter(maxSize, func() ObjectTarget { return benchTarget{} })
+		f, _ := newPayloadSizeLimiter(maxSize, func() ObjectWriter { return benchTarget{} })
 		if err := f.WriteHeader(ctx, header); err != nil {
 			b.Fatalf("write header: %v", err)
 		}
@@ -144,7 +144,7 @@ func benchmarkTransformer(b *testing.B, header *objectSDK.Object, payloadSize in
 	}
 }
 
-func newPayloadSizeLimiter(maxSize uint64, nextTarget func() ObjectTarget) (ObjectTarget, *keys.PrivateKey) {
+func newPayloadSizeLimiter(maxSize uint64, nextTarget TargetInitializer) (ChunkedObjectWriter, *keys.PrivateKey) {
 	p, err := keys.NewPrivateKey()
 	if err != nil {
 		panic(err)
@@ -167,38 +167,15 @@ func (s dummyEpochSource) CurrentEpoch() uint64 {
 
 type benchTarget struct{}
 
-func (benchTarget) WriteHeader(_ context.Context, object *objectSDK.Object) error {
+func (benchTarget) WriteObject(context.Context, *objectSDK.Object) error {
 	return nil
 }
 
-func (benchTarget) Write(_ context.Context, p []byte) (n int, err error) {
-	return len(p), nil
-}
-
-func (benchTarget) Close(context.Context) (*AccessIdentifiers, error) {
-	return nil, nil
-}
-
 type testTarget struct {
-	current *objectSDK.Object
-	payload []byte
 	objects []*objectSDK.Object
 }
 
-func (tt *testTarget) WriteHeader(_ context.Context, object *objectSDK.Object) error {
-	tt.current = object
-	return nil
-}
-
-func (tt *testTarget) Write(_ context.Context, p []byte) (n int, err error) {
-	tt.payload = append(tt.payload, p...)
-	return len(p), nil
-}
-
-func (tt *testTarget) Close(_ context.Context) (*AccessIdentifiers, error) {
-	tt.current.SetPayload(tt.payload)
-	tt.objects = append(tt.objects, tt.current)
-	tt.current = nil
-	tt.payload = nil
-	return nil, nil // AccessIdentifiers should not be used.
+func (tt *testTarget) WriteObject(_ context.Context, o *objectSDK.Object) error {
+	tt.objects = append(tt.objects, o)
+	return nil // AccessIdentifiers should not be used.
 }

object/transformer/types.go

@@ -21,8 +21,9 @@ type EpochSource interface {
 	CurrentEpoch() uint64
 }
 
-// ObjectTarget is an interface of the object writer.
-type ObjectTarget interface {
+// ChunkedObjectWriter is an interface of the object writer
+// that writes object chunked.
+type ChunkedObjectWriter interface {
 	// WriteHeader writes object header w/ payload part.
 	// The payload of the object may be incomplete.
 	//
@@ -51,5 +52,11 @@ type ObjectTarget interface {
 	Close(context.Context) (*AccessIdentifiers, error)
 }
 
-// TargetInitializer represents ObjectTarget constructor.
-type TargetInitializer func() ObjectTarget
+// TargetInitializer represents ObjectWriter constructor.
+type TargetInitializer func() ObjectWriter
+
+// ObjectWriter is an interface of the object writer that writes prepared object.
+type ObjectWriter interface {
+	// WriteObject writes prepared object.
+	WriteObject(context.Context, *object.Object) error
+}