Fix ref counted window close handling.

Instead of refcounting QWindow visibility, we ask the Application
subclass whether quitting is appropriate.

Task-Id: QTBUG-24120
Change-Id: Idd19cc1a3e5742fddded89c7638aaaa5e47c568d
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>

3 files changed, 35 insertions, 2 deletions

diff --git a/src/widgets/kernel/qapplication.cpp b/src/widgets/kernel/qapplication.cpp
index 4387d2a287..b04925d85d 100644
--- a/src/widgets/kernel/qapplication.cpp
+++ b/src/widgets/kernel/qapplication.cpp
@@ -67,6 +67,7 @@
 #include "private/qstylesheetstyle_p.h"
 #include "private/qstyle_p.h"
 #include "qmessagebox.h"
+#include "qwidgetwindow_qpa_p.h"
 #include <QtWidgets/qgraphicsproxywidget.h>
 #include <QtGui/qstylehints.h>
 #include <QtGui/qinputmethod.h>
@@ -3289,6 +3290,20 @@ int QApplication::exec()
     return QGuiApplication::exec();
 }
 
+bool QApplicationPrivate::shouldQuit()
+{
+    /* if there is no non-withdrawn primary window left (except
+        the ones without QuitOnClose), we emit the lastWindowClosed
+        signal */
+    QWidgetList list = QApplication::topLevelWidgets();
+    for (int i = 0; i < list.size(); ++i) {
+        QWidget *w = list.at(i);
+        if (w->isVisible() && !w->parentWidget() && w->testAttribute(Qt::WA_QuitOnClose))
+            return false;
+    }
+    return true;
+}
+
 /*! \reimp
  */
 bool QApplication::notify(QObject *receiver, QEvent *e)
diff --git a/src/widgets/kernel/qapplication_p.h b/src/widgets/kernel/qapplication_p.h
index 790176afe3..e728868182 100644
--- a/src/widgets/kernel/qapplication_p.h
+++ b/src/widgets/kernel/qapplication_p.h
@@ -178,6 +178,8 @@ public:
     virtual void notifyLayoutDirectionChange();
     virtual void notifyActiveWindowChange(QWindow *);
 
+    virtual bool shouldQuit();
+
 #if defined(Q_WS_X11)
 #ifndef QT_NO_SETTINGS
     static bool x11_apply_settings();
diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index f98f7fbe66..f095e475af 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -7410,8 +7410,24 @@ bool QWidgetPrivate::close_helper(CloseMode mode)
     // Attempt to close the application only if this has WA_QuitOnClose set and a non-visible parent
     quitOnClose = quitOnClose && (parentWidget.isNull() || !parentWidget->isVisible());
 
-    if (quitOnClose && q->windowHandle()) {
-        static_cast<QWindowPrivate*>(QObjectPrivate::get(q->windowHandle()))->maybeQuitOnLastWindowClosed();
+    if (quitOnClose) {
+        /* if there is no non-withdrawn primary window left (except
+           the ones without QuitOnClose), we emit the lastWindowClosed
+           signal */
+        QWidgetList list = QApplication::topLevelWidgets();
+        bool lastWindowClosed = true;
+        for (int i = 0; i < list.size(); ++i) {
+            QWidget *w = list.at(i);
+            if (!w->isVisible() || w->parentWidget() || !w->testAttribute(Qt::WA_QuitOnClose))
+                continue;
+            lastWindowClosed = false;
+            break;
+        }
+        if (lastWindowClosed) {
+            QGuiApplicationPrivate::emitLastWindowClosed();
+            QCoreApplicationPrivate *applicationPrivate = static_cast<QCoreApplicationPrivate*>(QObjectPrivate::get(QCoreApplication::instance()));
+            applicationPrivate->maybeQuit();
+        }
     }