[#164] sdk/object: Implement method to reset relation fields

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

pkg/object/raw.go

@@ -143,3 +143,8 @@ func (o *RawObject) CutPayload() *RawObject {
 
 	return nil
 }
+
+// ResetRelations removes all fields of links with other objects.
+func (o *RawObject) ResetRelations() {
+	o.resetRelations()
+}

pkg/object/raw_test.go

@@ -265,3 +265,13 @@ func TestRawObject_SetParentID(t *testing.T) {
 
 	require.Equal(t, id, obj.GetParentID())
 }
+
+func TestRawObject_ResetRelations(t *testing.T) {
+	obj := NewRaw()
+
+	obj.SetPreviousID(randID(t))
+
+	obj.ResetRelations()
+
+	require.Nil(t, obj.GetPreviousID())
+}

pkg/object/rw.go

@@ -296,6 +296,12 @@ func (o *rwObject) setParent(v *Object) {
 	})
 }
 
+func (o *rwObject) resetRelations() {
+	o.setHeaderField(func(h *object.Header) {
+		h.SetSplit(nil)
+	})
+}
+
 // GetSessionToken returns token of the session
 // within which object was created.
 func (o *rwObject) GetSessionToken() *token.SessionToken {