From e0c43ff624e05083fa0983391edec3af1ebe111c Mon Sep 17 00:00:00 2001
From: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Date: Tue, 15 Mar 2016 10:46:01 +0100
Subject: [PATCH] WIP: Purely experimental: Implement QWidget::create(winId) by
 QWindow::fromWinId().

Pass the win id to  QWidgetPrivate::create_sys() and use
QWindow::fromWinId() there. Change QTLWExtra::window to be a QWindow.

TODO: Is that worth following up or should QWidget::createWindowContainer()
be used always?

Task-number: QTBUG-33079
Task-number: QTBUG-51853
Change-Id: I3ed0cf212d27f68134219b26733bd73d44345fa9
---
 src/widgets/kernel/qwidget.cpp | 14 +++++++++-----
 src/widgets/kernel/qwidget_p.h |  5 ++---
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index 7bd4920..888286e 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -1406,7 +1406,7 @@ void QWidgetPrivate::create_sys(WId window, bool initializeWindow, bool destroyO
     // topData() ensures the extra is created but does not ensure 'window' is non-null
     // in case the extra was already valid.
     if (!win) {
-        createTLSysExtra();
+        createTLSysExtra(window);
         win = topData()->window;
     }
 
@@ -1419,7 +1419,8 @@ void QWidgetPrivate::create_sys(WId window, bool initializeWindow, bool destroyO
         win->setProperty("_q_showWithoutActivating", QVariant(true));
     if (q->testAttribute(Qt::WA_MacAlwaysShowToolWindow))
         win->setProperty("_q_macAlwaysShowToolWindow", QVariant::fromValue(QVariant(true)));
-    win->setFlags(data.window_flags);
+    if (win->type() != Qt::ForeignWindow) // ### fixme: Set flags or preserve Qt::ForeignWindow ?
+        win->setFlags(data.window_flags);
     fixPosIncludesFrame();
     if (q->testAttribute(Qt::WA_Moved)
         || !QGuiApplicationPrivate::platformIntegration()->hasCapability(QPlatformIntegration::WindowManagement))
@@ -1499,11 +1500,14 @@ void QWidgetPrivate::create_sys(WId window, bool initializeWindow, bool destroyO
 static const char activeXNativeParentHandleProperty[] = "_q_embedded_native_parent_handle";
 #endif
 
-void QWidgetPrivate::createTLSysExtra()
+void QWidgetPrivate::createTLSysExtra(WId id)
 {
     Q_Q(QWidget);
     if (!extra->topextra->window && (q->testAttribute(Qt::WA_NativeWindow) || q->isWindow())) {
-        extra->topextra->window = new QWidgetWindow(q);
+        if (id)
+            extra->topextra->window = QWindow::fromWinId(id);
+        else
+            extra->topextra->window = new QWidgetWindow(q);
         if (extra->minw || extra->minh)
             extra->topextra->window->setMinimumSize(QSize(extra->minw, extra->minh));
         if (extra->maxw != QWIDGETSIZE_MAX || extra->maxh != QWIDGETSIZE_MAX)
@@ -1877,7 +1881,7 @@ void QWidgetPrivate::deleteTLSysExtra()
         //delete the qglcontext before we delete the qplatformopenglcontext.
         //One unfortunate thing about this is that we potentially create a glContext just to
         //delete it straight afterwards.
-        if (extra->topextra->window) {
+        if (extra->topextra->window && extra->topextra->window->type() != Qt::ForeignWindow) {
             extra->topextra->window->destroy();
         }
         setWinId(0);
diff --git a/src/widgets/kernel/qwidget_p.h b/src/widgets/kernel/qwidget_p.h
index 7eb8d04..a7e372e 100644
--- a/src/widgets/kernel/qwidget_p.h
+++ b/src/widgets/kernel/qwidget_p.h
@@ -68,7 +68,6 @@ 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;
@@ -154,7 +153,7 @@ struct QTLWExtra {
     QWidgetBackingStoreTracker backingStoreTracker;
     QBackingStore *backingStore;
     QPainter *sharedPainter;
-    QWidgetWindow *window;
+    QWindow *window;
     QOpenGLContext *shareContext;
 
     // Implicit pointers (shared_null).
@@ -341,7 +340,7 @@ public:
     void deleteExtra();
     void createSysExtra();
     void deleteSysExtra();
-    void createTLSysExtra();
+    void createTLSysExtra(WId id = 0);
     void deleteTLSysExtra();
     void updateSystemBackground();
     void propagatePaletteChange();
-- 
2.5.0.windows.1