[#233] services/object: Implement new Get algorithm

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

pkg/services/object/get/util.go

@@ -0,0 +1,110 @@
+package getsvc
+
+import (
+	"context"
+	"crypto/ecdsa"
+
+	"github.com/nspcc-dev/neofs-api-go/pkg/client"
+	objectSDK "github.com/nspcc-dev/neofs-api-go/pkg/object"
+	"github.com/nspcc-dev/neofs-node/pkg/core/object"
+	"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/engine"
+	"github.com/nspcc-dev/neofs-node/pkg/network/cache"
+	headsvc "github.com/nspcc-dev/neofs-node/pkg/services/object/head"
+)
+
+type simpleObjectWriter struct {
+	obj *object.RawObject
+
+	payload []byte
+}
+
+type clientCacheWrapper struct {
+	cache *cache.ClientCache
+
+	opts []client.Option
+}
+
+type clientWrapper struct {
+	client *client.Client
+}
+
+type storageEngineWrapper struct {
+	engine *engine.StorageEngine
+}
+
+type headSvcWrapper struct {
+	svc *headsvc.Service
+}
+
+func newSimpleObjectWriter() *simpleObjectWriter {
+	return new(simpleObjectWriter)
+}
+
+func (s *simpleObjectWriter) WriteHeader(obj *object.Object) error {
+	s.obj = object.NewRawFromObject(obj)
+
+	s.payload = make([]byte, 0, obj.PayloadSize())
+
+	return nil
+}
+
+func (s *simpleObjectWriter) WriteChunk(p []byte) error {
+	s.payload = append(s.payload, p...)
+	return nil
+}
+
+func (s *simpleObjectWriter) Close() error {
+	return nil
+}
+
+func (s *simpleObjectWriter) object() *object.Object {
+	if len(s.payload) > 0 {
+		s.obj.SetPayload(s.payload)
+	}
+
+	return s.obj.Object()
+}
+
+func (c *clientCacheWrapper) get(key *ecdsa.PrivateKey, addr string) (getClient, error) {
+	clt, err := c.cache.Get(key, addr, c.opts...)
+
+	return &clientWrapper{
+		client: clt,
+	}, err
+}
+
+func (c *clientWrapper) GetObject(ctx context.Context, p Prm) (*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...,
+	)
+}
+
+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
+	}
+
+	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).
+		WithCommonPrm(p.common).
+		Short(false),
+	)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return r.Header(), nil
+}