reworked all timeline commands

I'll be honest, this stuff probably caused a lot of crashes. Objects were constantly created and destroyed without the foresight that other commands might be using them. This should fix a lot of that.

app/widget/timelinewidget/CMakeLists.txt

@@ -22,7 +22,6 @@ set(OLIVE_SOURCES
   ${OLIVE_SOURCES}
   widget/timelinewidget/timelineandtrackview.cpp
   widget/timelinewidget/timelineandtrackview.h
-  widget/timelinewidget/timelineundo.cpp
   widget/timelinewidget/timelineundo.h
   widget/timelinewidget/timelinewidget.cpp
   widget/timelinewidget/timelinewidget.h

app/widget/timelinewidget/timelinewidget.cpp

@@ -469,9 +469,7 @@ void TimelineWidget::DeleteSelected(bool ripple)
 
   // For transitions, remove them but extend their attached blocks to fill their place
   foreach (TransitionBlock* transition, transitions_to_delete) {
-    new TransitionRemoveCommand(transition->track(),
-                                transition,
-                                command);
+    new TransitionRemoveCommand(transition, command);
 
     Node::RemoveNodesAndExclusiveDependencies(transition, command);
   }
@@ -480,7 +478,7 @@ void TimelineWidget::DeleteSelected(bool ripple)
   ReplaceBlocksWithGaps(clips_to_delete, true, command);
 
   // Remove all selections
-  new TimelineSetSelectionsCommand(this, TimelineWidgetSelections(), GetSelections(), command);
+  new SetSelectionsCommand(this, TimelineWidgetSelections(), GetSelections(), command);
 
   // Insert ripple command now that it's all cleaned up gaps
   if (ripple) {

app/widget/timelinewidget/timelinewidget.h

@@ -195,6 +195,34 @@ public:
    */
   void SignalDeselectedAllBlocks();
 
+  class SetSelectionsCommand : public QUndoCommand {
+  public:
+    SetSelectionsCommand(TimelineWidget* timeline, const TimelineWidgetSelections& now, const TimelineWidgetSelections& old, QUndoCommand* parent = nullptr) :
+      QUndoCommand(parent),
+      timeline_(timeline),
+      old_(old),
+      now_(now)
+    {
+    }
+
+  protected:
+    virtual void redo() override
+    {
+      timeline_->SetSelections(now_);
+    }
+
+    virtual void undo() override
+    {
+      timeline_->SetSelections(old_);
+    }
+
+  private:
+    TimelineWidget* timeline_;
+    TimelineWidgetSelections old_;
+    TimelineWidgetSelections now_;
+
+  };
+
 signals:
   void BlocksSelected(const QVector<Block*>& selected_blocks);
 

app/widget/timelinewidget/tool/pointer.cpp

@@ -590,7 +590,7 @@ void PointerTool::FinishDrag(TimelineViewMouseEvent *event)
       } else {
         new_sel.TrimOut(reference_ghost->GetOutAdjustment());
       }
-      new TimelineSetSelectionsCommand(parent(), new_sel, parent()->GetSelections(), command);
+      new TimelineWidget::SetSelectionsCommand(parent(), new_sel, parent()->GetSelections(), command);
     }
   }
 
@@ -655,7 +655,7 @@ void PointerTool::FinishDrag(TimelineViewMouseEvent *event)
     TimelineWidgetSelections new_sel = parent()->GetSelections();
     new_sel.ShiftTime(blocks_moving.first().ghost->GetInAdjustment());
     new_sel.ShiftTracks(drag_track_type_, blocks_moving.first().ghost->GetTrackAdjustment());
-    new TimelineSetSelectionsCommand(parent(), new_sel, parent()->GetSelections(), command);
+    new TimelineWidget::SetSelectionsCommand(parent(), new_sel, parent()->GetSelections(), command);
   }
 
   if (!blocks_sliding.isEmpty()) {
@@ -717,7 +717,7 @@ void PointerTool::FinishDrag(TimelineViewMouseEvent *event)
       // Adjust selections
       TimelineWidgetSelections new_sel = parent()->GetSelections();
       new_sel.ShiftTime(movement);
-      new TimelineSetSelectionsCommand(parent(), new_sel, parent()->GetSelections(), command);
+      new TimelineWidget::SetSelectionsCommand(parent(), new_sel, parent()->GetSelections(), command);
     }
   }
 

app/widget/timelinewidget/tool/ripple.cpp

@@ -138,7 +138,7 @@ void RippleTool::FinishDrag(TimelineViewMouseEvent *event)
       } else {
         new_sel.TrimOut(reference_ghost->GetOutAdjustment());
       }
-      new TimelineSetSelectionsCommand(parent(), new_sel, parent()->GetSelections(), command);
+      new TimelineWidget::SetSelectionsCommand(parent(), new_sel, parent()->GetSelections(), command);
     }
 
     Core::instance()->undo_stack()->pushIfHasChildren(command);