Update settings on fullscreen change

The OS could kick us out of fullscreen without our interaction, which
means that we'll need to update the fullscreen setting as well (it would
remain stuck in its old, outdated state if we didn't).

To avoid possible recursion and ping-pong issues when writing the
setting, we need to ignore update notifications if we are changing the
setting ourselves. Since Qt does not have a mechanism for selective
signal blocking, we use a simple counter to to ignore settings
notifications (and a slightly less simple RAII wrapper to reset the
counter in an exception-safe way).

src/ui/KonvergoWindow.cpp

@@ -19,7 +19,7 @@
 #include "EventFilter.h"
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
-KonvergoWindow::KonvergoWindow(QWindow* parent) : QQuickWindow(parent), m_debugLayer(false), m_lastScale(1.0)
+KonvergoWindow::KonvergoWindow(QWindow* parent) : QQuickWindow(parent), m_debugLayer(false), m_lastScale(1.0), m_ignoreFullscreenSettingsChange(0)
 {
   // NSWindowCollectionBehaviorFullScreenPrimary is only set on OSX if Qt::WindowFullscreenButtonHint is set on the window.
   setFlags(flags() | Qt::WindowFullscreenButtonHint);
@@ -230,6 +230,9 @@ void KonvergoWindow::playerWindowVisible(bool visible)
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 void KonvergoWindow::updateMainSectionSettings(const QVariantMap& values)
 {
+  if (m_ignoreFullscreenSettingsChange > 0)
+    return;
+
   // update mouse visibility if needed
   if (values.find("disablemouse") != values.end())
   {
@@ -272,6 +275,17 @@ void KonvergoWindow::updateWindowState(bool saveGeo)
   }
 }
 
+///////////////////////////////////////////////////////////////////////////////////////////////////
+class ScopedDecrementer {
+  Q_DISABLE_COPY(ScopedDecrementer)
+
+  int* m_value;
+
+public:
+  ScopedDecrementer(int* value) : m_value(value) {}
+  ~ScopedDecrementer() { (*m_value)--; }
+};
+
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 void KonvergoWindow::onVisibilityChanged(QWindow::Visibility visibility)
 {
@@ -280,6 +294,15 @@ void KonvergoWindow::onVisibilityChanged(QWindow::Visibility visibility)
   if (visibility == QWindow::Windowed)
     loadGeometry();
 
+  bool fs = visibility == QWindow::FullScreen;
+
+  {
+    m_ignoreFullscreenSettingsChange++;
+    ScopedDecrementer decrement(&m_ignoreFullscreenSettingsChange);
+
+    SettingsComponent::Get().setValue(SETTINGS_SECTION_MAIN, "fullscreen", fs);
+  }
+
   if (visibility == QWindow::FullScreen)
     PowerComponent::Get().setFullscreenState(true);
   else if (visibility == QWindow::Windowed)

src/ui/KonvergoWindow.h

@@ -124,6 +124,7 @@ private:
   qreal m_lastScale;
   QTimer* m_infoTimer;
   QString m_debugInfo, m_systemDebugInfo, m_videoInfo;
+  int m_ignoreFullscreenSettingsChange;
 };
 
 #endif // KONVERGOWINDOW_H