[#1307] object: Implement Patch method

Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>

pkg/services/object/patch/range_provider.go

@@ -0,0 +1,63 @@
+package patchsvc
+
+import (
+	"context"
+	"crypto/ecdsa"
+	"io"
+
+	getsvc "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object/get"
+	objectUtil "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object/util"
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
+	patcherSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/patcher"
+)
+
+func (p *pipeChunkWriter) WriteChunk(_ context.Context, chunk []byte) error {
+	_, err := p.wr.Write(chunk)
+	return err
+}
+
+type rangeProvider struct {
+	getSvc *getsvc.Service
+
+	addr oid.Address
+
+	commonPrm *objectUtil.CommonPrm
+
+	localNodeKey *ecdsa.PrivateKey
+}
+
+var _ patcherSDK.RangeProvider = (*rangeProvider)(nil)
+
+func (r *rangeProvider) GetRange(ctx context.Context, rng *objectSDK.Range) io.Reader {
+	pipeReader, pipeWriter := io.Pipe()
+
+	var rngPrm getsvc.RangePrm
+	rngPrm.SetSignerKey(r.localNodeKey)
+	rngPrm.SetCommonParameters(r.commonPrm)
+
+	rngPrm.WithAddress(r.addr)
+	rngPrm.SetChunkWriter(&pipeChunkWriter{
+		wr: pipeWriter,
+	})
+	rngPrm.SetRange(rng)
+
+	getRangeErr := make(chan error)
+
+	go func() {
+		defer pipeWriter.Close()
+
+		select {
+		case <-ctx.Done():
+			pipeWriter.CloseWithError(ctx.Err())
+		case err := <-getRangeErr:
+			pipeWriter.CloseWithError(err)
+		}
+	}()
+
+	go func() {
+		getRangeErr <- r.getSvc.GetRange(ctx, rngPrm)
+	}()
+
+	return pipeReader
+}