Make moving a marker undoable

app/timeline/timelinemarker.cpp

@@ -46,6 +46,12 @@ void TimelineMarker::set_time(const TimeRange &time)
   emit TimeChanged(time_);
 }
 
+void TimelineMarker::set_time_undo(TimeRange time) {
+  UndoCommand *command = new MarkerChangeTimeCommand(Core::instance()->GetActiveProject(), this, time);
+
+  Core::instance()->undo_stack()->push(command);
+}
+
 const QString &TimelineMarker::name() const
 {
   return name_;

app/timeline/timelinemarker.h

@@ -52,6 +52,7 @@ public:
 
 public slots:
   void set_name_undo(QString name);
+  void set_time_undo(TimeRange time);
 
 signals:
   void TimeChanged(const TimeRange& time);

app/widget/marker/markerundo.cpp

@@ -112,4 +112,27 @@ void MarkerChangeNameCommand::undo()
   marker_->set_name(old_name_);
 }
 
+MarkerChangeTimeCommand::MarkerChangeTimeCommand(Project* project, TimelineMarker* marker, TimeRange time) :
+    project_(project),
+    marker_(marker),
+    old_time_(marker->time()),
+    new_time_(time)
+{
+}
+
+Project* MarkerChangeTimeCommand::GetRelevantProject() const
+{
+  return project_;
+}
+
+void MarkerChangeTimeCommand::redo()
+{
+  marker_->set_time(new_time_);
+}
+
+void MarkerChangeTimeCommand::undo()
+{
+  marker_->set_time(old_time_);
+}
+
 }

app/widget/marker/markerundo.h

@@ -95,6 +95,25 @@ class MarkerChangeNameCommand : public UndoCommand {
   QString new_name_;
 };
 
+class MarkerChangeTimeCommand : public UndoCommand {
+  public:
+    MarkerChangeTimeCommand(Project* project, TimelineMarker* marker, TimeRange time);
+
+    virtual Project* GetRelevantProject() const override;
+
+  protected:
+    virtual void redo() override;
+    virtual void undo() override;
+
+  private:
+    Project* project_;
+    TimelineMarker* marker_;
+    TimeRange old_time_;
+    TimeRange new_time_;
+
+
+};
+
 }
 
 #endif  // TIMELINEUNDOTRACK_H

app/widget/timeruler/seekablewidget.cpp

@@ -220,7 +220,7 @@ void SeekableWidget::addMarker(TimelineMarker* marker)
     connect(marker_widget, &Marker::NameChanged, marker, &TimelineMarker::set_name_undo);
     connect(marker, &TimelineMarker::NameChanged, marker_widget, &Marker::SetName);
 
-    connect(marker_widget, &Marker::TimeChanged, marker, &TimelineMarker::set_time);
+    connect(marker_widget, &Marker::TimeChanged, marker, &TimelineMarker::set_time_undo);
     connect(marker, &TimelineMarker::TimeChanged, marker_widget, &Marker::SetTime);
 
     marker_widget->move(TimeToScreen(marker->time().in())-2, text_height_);