[#XX] patcher: Add closer

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

object/patcher/patcher.go

@@ -47,7 +47,7 @@ type RangeProvider interface {
 	// GetRange reads an original object payload by the given range.
 	// The method returns io.Reader over the data range only. This means if the data is read out,
 	// then GetRange has to be invoked to provide reader over the next range.
-	GetRange(ctx context.Context, rng *objectSDK.Range) io.Reader
+	GetRange(ctx context.Context, rng *objectSDK.Range) io.ReadCloser
 }
 
 type patcher struct {
@@ -170,6 +170,7 @@ func (p *patcher) Close(ctx context.Context) (PatchRes, error) {
 
 func (p *patcher) copyRange(ctx context.Context, rng *objectSDK.Range) error {
 	rdr := p.rangeProvider.GetRange(ctx, rng)
+	defer func() { _ = rdr.Close() }()
 	for {
 		buffOrigPayload := make([]byte, p.readerBuffSize)
 		n, readErr := rdr.Read(buffOrigPayload)

object/patcher/patcher_test.go

@@ -41,14 +41,22 @@ type mockRangeProvider struct {
 
 var _ RangeProvider = (*mockRangeProvider)(nil)
 
-func (m *mockRangeProvider) GetRange(_ context.Context, rng *objectSDK.Range) io.Reader {
+func (m *mockRangeProvider) GetRange(_ context.Context, rng *objectSDK.Range) io.ReadCloser {
 	offset := rng.GetOffset()
 	length := rng.GetLength()
 
 	if length == 0 {
-		return bytes.NewReader(m.originalObjectPayload[offset:])
+		return &readCloserImpl{bytes.NewReader(m.originalObjectPayload[offset:])}
 	}
-	return bytes.NewReader(m.originalObjectPayload[offset : offset+length])
+	return &readCloserImpl{bytes.NewReader(m.originalObjectPayload[offset : offset+length])}
+}
+
+type readCloserImpl struct {
+	*bytes.Reader
+}
+
+func (*readCloserImpl) Close() error {
+	return nil
 }
 
 func newTestObject() (*objectSDK.Object, oid.Address) {