[#235] services/object: Implement new GetRange algorithm

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/services/object/get/util.go

@@ -15,7 +15,7 @@ import (
 type simpleObjectWriter struct {
 	obj *object.RawObject
 
-	payload []byte
+	pld []byte
 }
 
 type clientCacheWrapper struct {
@@ -36,20 +36,28 @@ type headSvcWrapper struct {
 	svc *headsvc.Service
 }
 
+type rangeWriter struct {
+	ObjectWriter
+
+	chunkWriter ChunkWriter
+}
+
 func newSimpleObjectWriter() *simpleObjectWriter {
-	return new(simpleObjectWriter)
+	return &simpleObjectWriter{
+		obj: object.NewRaw(),
+	}
 }
 
 func (s *simpleObjectWriter) WriteHeader(obj *object.Object) error {
 	s.obj = object.NewRawFromObject(obj)
 
-	s.payload = make([]byte, 0, obj.PayloadSize())
+	s.pld = make([]byte, 0, obj.PayloadSize())
 
 	return nil
 }
 
 func (s *simpleObjectWriter) WriteChunk(p []byte) error {
-	s.payload = append(s.payload, p...)
+	s.pld = append(s.pld, p...)
 	return nil
 }
 
@@ -58,8 +66,8 @@ func (s *simpleObjectWriter) Close() error {
 }
 
 func (s *simpleObjectWriter) object() *object.Object {
-	if len(s.payload) > 0 {
-		s.obj.SetPayload(s.payload)
+	if len(s.pld) > 0 {
+		s.obj.SetPayload(s.pld)
 	}
 
 	return s.obj.Object()
@@ -73,31 +81,60 @@ func (c *clientCacheWrapper) get(key *ecdsa.PrivateKey, addr string) (getClient,
 	}, err
 }
 
-func (c *clientWrapper) GetObject(ctx context.Context, p Prm) (*objectSDK.Object, error) {
+func (c *clientWrapper) GetObject(ctx context.Context, p RangePrm) (*objectSDK.Object, error) {
 	// we don't specify payload writer because we accumulate
 	// the object locally (even huge).
-	return c.client.GetObject(ctx,
-		new(client.GetObjectParams).
-			WithAddress(p.addr).
-			WithRawFlag(true),
-		p.callOpts...,
-	)
+	if p.rng != nil {
+		data, err := c.client.ObjectPayloadRangeData(ctx,
+			new(client.RangeDataParams).
+				WithAddress(p.Address()).
+				WithRange(p.rng).
+				WithRaw(p.RawFlag()),
+			p.callOpts...,
+		)
+		if err != nil {
+			return nil, err
+		}
+
+		return payloadOnlyObject(data), nil
+	} else {
+		// we don't specify payload writer because we accumulate
+		// the object locally (even huge).
+		return c.client.GetObject(ctx,
+			new(client.GetObjectParams).
+				WithAddress(p.Address()).
+				WithRawFlag(p.RawFlag()),
+			p.callOpts...,
+		)
+	}
 }
 
-func (e *storageEngineWrapper) Get(addr *objectSDK.Address) (*object.Object, error) {
-	r, err := e.engine.Get(new(engine.GetPrm).
-		WithAddress(addr),
-	)
-	if err != nil {
-		return nil, err
-	}
+func (e *storageEngineWrapper) Get(p RangePrm) (*object.Object, error) {
+	if p.rng != nil {
+		r, err := e.engine.GetRange(new(engine.RngPrm).
+			WithAddress(p.Address()).
+			WithPayloadRange(p.rng),
+		)
+		if err != nil {
+			return nil, err
+		}
 
-	return r.Object(), nil
+		return r.Object(), nil
+	} else {
+		r, err := e.engine.Get(new(engine.GetPrm).
+			WithAddress(p.Address()),
+		)
+		if err != nil {
+			return nil, err
+		}
+
+		return r.Object(), nil
+	}
 }
 
 func (s *headSvcWrapper) head(ctx context.Context, p Prm) (*object.Object, error) {
 	r, err := s.svc.Head(ctx, new(headsvc.Prm).
-		WithAddress(p.addr).
+		WithAddress(p.Address()).
 		WithCommonPrm(p.common).
 		Short(false),
 	)
@@ -108,3 +145,14 @@ func (s *headSvcWrapper) head(ctx context.Context, p Prm) (*object.Object, error
 
 	return r.Header(), nil
 }
+
+func (w *rangeWriter) WriteChunk(p []byte) error {
+	return w.chunkWriter.WriteChunk(p)
+}
+
+func payloadOnlyObject(payload []byte) *objectSDK.Object {
+	rawObj := object.NewRaw()
+	rawObj.SetPayload(payload)
+
+	return rawObj.Object().SDK()
+}