QtWidgets: Change QTLWExtra::window from QWindow to QWidgetWindow

Revert commit a1d4e4c9: We’re now using QWidgetWindow
API from QWidget code.

Add QWidgetPrivate::windowHandle() which returns
a QWidgetWindow pointer. Use this function to remove
casts where QWidgetWindow API is used.

Change-Id: Ie66a69b5c0461f297996118dc907e1d7b3d78df5
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

2 files changed, 15 insertions, 11 deletions

diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index b9aff2a58b..95e1a247bb 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -1415,7 +1415,7 @@ void QWidgetPrivate::create_sys(WId window, bool initializeWindow, bool destroyO
     if (!q->testAttribute(Qt::WA_NativeWindow) && !q->isWindow())
         return; // we only care about real toplevels
 
-    QWindow *win = topData()->window;
+    QWidgetWindow *win = topData()->window;
     // topData() ensures the extra is created but does not ensure 'window' is non-null
     // in case the extra was already valid.
     if (!win) {
@@ -1516,8 +1516,7 @@ void QWidgetPrivate::create_sys(WId window, bool initializeWindow, bool destroyO
         q->setAttribute(Qt::WA_OutsideWSRange, true);
     } else if (q->isVisible()) {
         // If widget is already shown, set window visible, too
-        QWidgetWindow *widgetWindow = qobject_cast<QWidgetWindow *>(win);
-        widgetWindow->setNativeWindowVisibility(true);
+        win->setNativeWindowVisibility(true);
     }
 }
 
@@ -2640,11 +2639,7 @@ WId QWidget::effectiveWinId() const
 QWindow *QWidget::windowHandle() const
 {
     Q_D(const QWidget);
-    QTLWExtra *extra = d->maybeTopData();
-    if (extra)
-        return extra->window;
-
-    return 0;
+    return d->windowHandle();
 }
 
 #ifndef QT_NO_STYLE_STYLESHEET
@@ -7955,7 +7950,7 @@ void QWidgetPrivate::show_sys()
 {
     Q_Q(QWidget);
 
-    QWidgetWindow *window = qobject_cast<QWidgetWindow *>(q->windowHandle());
+    QWidgetWindow *window = windowHandle();
 
     if (q->testAttribute(Qt::WA_DontShowOnScreen)) {
         invalidateBuffer(q->rect());
@@ -8094,7 +8089,7 @@ void QWidgetPrivate::hide_sys()
 {
     Q_Q(QWidget);
 
-    QWidgetWindow *window = qobject_cast<QWidgetWindow *>(q->windowHandle());
+    QWidgetWindow *window = windowHandle();
 
     if (q->testAttribute(Qt::WA_DontShowOnScreen)) {
         q->setAttribute(Qt::WA_Mapped, false);
diff --git a/src/widgets/kernel/qwidget_p.h b/src/widgets/kernel/qwidget_p.h
index 2c397aec88..b830895788 100644
--- a/src/widgets/kernel/qwidget_p.h
+++ b/src/widgets/kernel/qwidget_p.h
@@ -76,6 +76,7 @@ QT_BEGIN_NAMESPACE
 // Extra QWidget data
 //  - to minimize memory usage for members that are seldom used.
 //  - top-level widgets have extra extra data to reduce cost further
+class QWidgetWindow;
 class QPaintEngine;
 class QPixmap;
 class QWidgetBackingStore;
@@ -160,7 +161,7 @@ struct QTLWExtra {
     QWidgetBackingStoreTracker backingStoreTracker;
     QBackingStore *backingStore;
     QPainter *sharedPainter;
-    QWindow *window;
+    QWidgetWindow *window;
     QOpenGLContext *shareContext;
 
     // Implicit pointers (shared_null).
@@ -338,6 +339,7 @@ public:
     QPainter *sharedPainter() const;
     void setSharedPainter(QPainter *painter);
     QWidgetBackingStore *maybeBackingStore() const;
+    QWidgetWindow *windowHandle() const;
     void init(QWidget *desktopWidget, Qt::WindowFlags f);
     void create_sys(WId window, bool initializeWindow, bool destroyOldWindow);
     void createRecursively();
@@ -987,6 +989,13 @@ inline QWidgetBackingStore *QWidgetPrivate::maybeBackingStore() const
     return x ? x->backingStoreTracker.data() : 0;
 }
 
+inline QWidgetWindow *QWidgetPrivate::windowHandle() const
+{
+    if (QTLWExtra *x = maybeTopData())
+        return x->window;
+    return nullptr;
+}
+
 QT_END_NAMESPACE
 
 #endif // QWIDGET_P_H