Fix focus handling of native child widgets in xcb.

Change-Id: If4d596195624011142bff6853849a23064e478df
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>
(cherry picked from commit fc663b5f9a)

src/gui/kernel/qwindow_p.h

@@ -120,6 +120,8 @@ public:
         return offset;
     }
 
+    virtual QWindow *eventReceiver() { Q_Q(QWindow); return q; }
+
     QWindow::SurfaceType surfaceType;
     Qt::WindowFlags windowFlags;
     QWindow *parentWindow;

src/plugins/platforms/xcb/qxcbconnection.cpp

@@ -258,6 +258,7 @@ QXcbConnection::QXcbConnection(QXcbNativeInterface *nativeInterface, const char
     , has_randr_extension(false)
     , has_input_shape(false)
     , m_buttons(0)
+    , m_focusWindow(0)
 {
 #ifdef XCB_USE_XLIB
     Display *dpy = XOpenDisplay(m_displayName.constData());
@@ -418,7 +419,7 @@ break;
     if (QXcbWindow *platformWindow = platformWindowFromId(e->event)) { \
         handled = QWindowSystemInterface::handleNativeEvent(platformWindow->window(), m_nativeInterface->genericEventFilterType(), event, &result); \
         if (!handled) \
-            m_keyboard->handler(platformWindow, e); \
+            m_keyboard->handler(m_focusWindow, e); \
     } \
 } \
 break;
@@ -943,6 +944,11 @@ void QXcbEventReader::unlock()
     m_mutex.unlock();
 }
 
+void QXcbConnection::setFocusWindow(QXcbWindow *w)
+{
+    m_focusWindow = w;
+}
+
 void QXcbConnection::sendConnectionEvent(QXcbAtom::Atom a, uint id)
 {
     xcb_client_message_event_t event;

src/plugins/platforms/xcb/qxcbconnection.h

@@ -385,6 +385,9 @@ public:
 
     Qt::MouseButtons buttons() const { return m_buttons; }
 
+    QXcbWindow *focusWindow() const { return m_focusWindow; }
+    void setFocusWindow(QXcbWindow *);
+
 private slots:
     void processXcbEvents();
 
@@ -511,6 +514,8 @@ private:
     bool has_input_shape;
 
     Qt::MouseButtons m_buttons;
+
+    QXcbWindow *m_focusWindow;
 };
 
 #define DISPLAY_FROM_XCB(object) ((Display *)(object->connection()->xlib_display()))

src/plugins/platforms/xcb/qxcbwindow.cpp

@@ -403,6 +403,9 @@ QXcbWindow::~QXcbWindow()
 
 void QXcbWindow::destroy()
 {
+    if (connection()->focusWindow() == this)
+        connection()->setFocusWindow(0);
+
     if (m_syncCounter && m_screen->syncRequestSupported())
         Q_XCB_CALL(xcb_sync_destroy_counter(xcb_connection(), m_syncCounter));
     if (m_window) {
@@ -1473,6 +1476,11 @@ void QXcbWindow::handleUnmapNotifyEvent(const xcb_unmap_notify_event_t *event)
 
 void QXcbWindow::handleButtonPressEvent(const xcb_button_press_event_t *event)
 {
+    if (window() != QGuiApplication::focusWindow()) {
+        QWindow *w = static_cast<QWindowPrivate *>(QObjectPrivate::get(window()))->eventReceiver();
+        w->requestActivate();
+    }
+
     updateNetWmUserTime(event->time);
 
     QPoint local(event->event_x, event->event_y);
@@ -1635,7 +1643,10 @@ void QXcbWindow::handlePropertyNotifyEvent(const xcb_property_notify_event_t *ev
 
 void QXcbWindow::handleFocusInEvent(const xcb_focus_in_event_t *)
 {
-    QWindowSystemInterface::handleWindowActivated(window());
+    QWindow *w = window();
+    w = static_cast<QWindowPrivate *>(QObjectPrivate::get(w))->eventReceiver();
+    connection()->setFocusWindow(static_cast<QXcbWindow *>(w->handle()));
+    QWindowSystemInterface::handleWindowActivated(w);
 }
 
 static bool focusInPeeker(xcb_generic_event_t *event)
@@ -1651,6 +1662,7 @@ static bool focusInPeeker(xcb_generic_event_t *event)
 
 void QXcbWindow::handleFocusOutEvent(const xcb_focus_out_event_t *)
 {
+    connection()->setFocusWindow(0);
     // Do not set the active window to 0 if there is a FocusIn coming.
     // There is however no equivalent for XPutBackEvent so register a
     // callback for QXcbConnection instead.

src/widgets/kernel/qwidgetwindow.cpp

@@ -39,6 +39,7 @@
 **
 ****************************************************************************/
 
+#include "private/qwindow_p.h"
 #include "qwidgetwindow_qpa_p.h"
 
 #include "private/qwidget_p.h"
@@ -60,8 +61,23 @@ extern int openPopupCount;
 bool qt_replay_popup_mouse_event = false;
 extern bool qt_try_modal(QWidget *widget, QEvent::Type type);
 
+class QWidgetWindowPrivate : public QWindowPrivate
+{
+    Q_DECLARE_PUBLIC(QWidgetWindow)
+public:
+    QWindow *eventReceiver() {
+        Q_Q(QWidgetWindow);
+        QWindow *w = q;
+        while (w->parent() && qobject_cast<QWidgetWindow *>(w) && qobject_cast<QWidgetWindow *>(w->parent())) {
+            w = w->parent();
+        }
+        return w;
+    }
+};
+
 QWidgetWindow::QWidgetWindow(QWidget *widget)
-    : m_widget(widget)
+    : QWindow(*new QWidgetWindowPrivate(), 0)
+    , m_widget(widget)
 {
     updateObjectName();
     connect(m_widget, &QObject::objectNameChanged, this, &QWidgetWindow::updateObjectName);