viewer: ensure view is updated if the cache is shifted

Also moves "ForceUpdate" to a queued connection so it occurs as soon as
the rest of the processing is done. This ensures the viewer isn't updated
too early.

app/render/playbackcache.cpp

@@ -82,7 +82,11 @@ void PlaybackCache::Shift(const rational &from, const rational &to)
     locker.unlock();
 
     emit Invalidated(invalidate_range);
+  } else {
+    locker.unlock();
   }
+
+  emit Shifted(from, to);
 }
 
 void PlaybackCache::Validate(const TimeRange &r)

app/render/playbackcache.h

@@ -75,6 +75,8 @@ signals:
 
   void Validated(const OLIVE_NAMESPACE::TimeRange& r);
 
+  void Shifted(const OLIVE_NAMESPACE::rational& from, const OLIVE_NAMESPACE::rational& to);
+
   void LengthChanged(const OLIVE_NAMESPACE::rational& r);
 
 protected:

app/widget/viewer/viewer.cpp

@@ -177,6 +177,7 @@ void ViewerWidget::ConnectNodeInternal(ViewerOutput *n)
   connect(n, &ViewerOutput::LengthChanged, this, &ViewerWidget::LengthChangedSlot);
   connect(n, &ViewerOutput::ParamsChanged, this, &ViewerWidget::UpdateRendererParameters);
   connect(n->video_frame_cache(), &FrameHashCache::Invalidated, this, &ViewerWidget::ViewerInvalidatedVideoRange);
+  connect(n->video_frame_cache(), &FrameHashCache::Shifted, this, &ViewerWidget::ViewerShiftedRange);
   connect(n->audio_playback_cache(), &FrameHashCache::Invalidated, this, &ViewerWidget::ViewerInvalidatedRange);
   connect(n, &ViewerOutput::GraphChangedFrom, this, &ViewerWidget::UpdateStack);
 
@@ -231,6 +232,7 @@ void ViewerWidget::DisconnectNodeInternal(ViewerOutput *n)
   disconnect(n, &ViewerOutput::LengthChanged, this, &ViewerWidget::LengthChangedSlot);
   disconnect(n, &ViewerOutput::ParamsChanged, this, &ViewerWidget::UpdateRendererParameters);
   disconnect(n->video_frame_cache(), &FrameHashCache::Invalidated, this, &ViewerWidget::ViewerInvalidatedVideoRange);
+  disconnect(n->video_frame_cache(), &FrameHashCache::Shifted, this, &ViewerWidget::ViewerShiftedRange);
   disconnect(n->audio_playback_cache(), &FrameHashCache::Invalidated, this, &ViewerWidget::ViewerInvalidatedRange);
   disconnect(n, &ViewerOutput::GraphChangedFrom, this, &ViewerWidget::UpdateStack);
 
@@ -1204,7 +1206,7 @@ void ViewerWidget::SetZoomFromMenu(QAction *action)
 void ViewerWidget::ViewerInvalidatedVideoRange(const TimeRange &range)
 {
   if (GetTime() >= range.in() && (GetTime() < range.out() || range.in() == range.out())) {
-    ForceUpdate();
+    QMetaObject::invokeMethod(this, "ForceUpdate", Qt::QueuedConnection);
   }
 
   ViewerInvalidatedRange();
@@ -1221,4 +1223,11 @@ void ViewerWidget::ViewerInvalidatedRange()
   }
 }
 
+void ViewerWidget::ViewerShiftedRange(const rational &from, const rational &to)
+{
+  if (GetTime() >= qMin(from, to)) {
+    QMetaObject::invokeMethod(this, "ForceUpdate", Qt::QueuedConnection);
+  }
+}
+
 OLIVE_NAMESPACE_EXIT

app/widget/viewer/viewer.h

@@ -85,8 +85,6 @@ public:
    */
   void SetFullScreen(QScreen* screen = nullptr);
 
-  void ForceUpdate();
-
   RenderBackend* renderer() const
   {
     return renderer_;
@@ -122,6 +120,8 @@ public slots:
    */
   void SetSignalCursorColorEnabled(bool e);
 
+  void ForceUpdate();
+
 signals:
   /**
    * @brief Wrapper for ViewerGLWidget::CursorColor()
@@ -272,6 +272,8 @@ private slots:
 
   void ViewerInvalidatedRange();
 
+  void ViewerShiftedRange(const OLIVE_NAMESPACE::rational& from, const OLIVE_NAMESPACE::rational& to);
+
   void UpdateStack();
 
   void ContextMenuSetFullScreen(QAction* action);