Update synctree to be able to provide listener

commonspace/object/tree/synctree/mock_synctree/mock_synctree.go

@@ -9,6 +9,7 @@ import (
 	reflect "reflect"
 
 	objecttree "github.com/anytypeio/any-sync/commonspace/object/tree/objecttree"
+	updatelistener "github.com/anytypeio/any-sync/commonspace/object/tree/synctree/updatelistener"
 	treechangeproto "github.com/anytypeio/any-sync/commonspace/object/tree/treechangeproto"
 	treestorage "github.com/anytypeio/any-sync/commonspace/object/tree/treestorage"
 	spacesyncproto "github.com/anytypeio/any-sync/commonspace/spacesyncproto"
@@ -415,6 +416,18 @@ func (mr *MockSyncTreeMockRecorder) Root() *gomock.Call {
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Root", reflect.TypeOf((*MockSyncTree)(nil).Root))
 }
 
+// SetListener mocks base method.
+func (m *MockSyncTree) SetListener(arg0 updatelistener.UpdateListener) {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "SetListener", arg0)
+}
+
+// SetListener indicates an expected call of SetListener.
+func (mr *MockSyncTreeMockRecorder) SetListener(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "SetListener", reflect.TypeOf((*MockSyncTree)(nil).SetListener), arg0)
+}
+
 // SnapshotPath mocks base method.
 func (m *MockSyncTree) SnapshotPath() []string {
 	m.ctrl.T.Helper()

commonspace/object/tree/synctree/synctree.go

@@ -30,9 +30,14 @@ type HeadNotifiable interface {
 	UpdateHeads(id string, heads []string)
 }
 
+type ListenerSetter interface {
+	SetListener(listener updatelistener.UpdateListener)
+}
+
 type SyncTree interface {
 	objecttree.ObjectTree
 	synchandler.SyncHandler
+	ListenerSetter
 	Ping() (err error)
 }
 
@@ -218,6 +223,11 @@ func buildSyncTree(ctx context.Context, isFirstBuild bool, deps BuildDeps) (t Sy
 	return
 }
 
+func (s *syncTree) SetListener(listener updatelistener.UpdateListener) {
+	// this should be called under lock
+	s.listener = listener
+}
+
 func (s *syncTree) IterateFrom(id string, convert objecttree.ChangeConvertFunc, iterate objecttree.ChangeIterateFunc) (err error) {
 	if err = s.checkAlive(); err != nil {
 		return