XCB: fix that modal dialogs can go behind other process windows

Task-number: QTBUG-35302
Change-Id: I1ad7a66e530710d5338a15057254360dae676451
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

4 files changed, 93 insertions, 45 deletions

diff --git a/src/plugins/platforms/windows/qwindowscontext.cpp b/src/plugins/platforms/windows/qwindowscontext.cpp
index 6462cb8d3e..f66859b72a 100644
--- a/src/plugins/platforms/windows/qwindowscontext.cpp
+++ b/src/plugins/platforms/windows/qwindowscontext.cpp
@@ -49,11 +49,11 @@
 #include "qwindowsmime.h"
 #include "qwindowsinputcontext.h"
 #include "qwindowstabletsupport.h"
+#include <private/qguiapplication_p.h>
 #ifndef QT_NO_ACCESSIBILITY
 # include "accessible/qwindowsaccessibility.h"
 #endif
 #if !defined(Q_OS_WINCE) && !defined(QT_NO_SESSIONMANAGER)
-# include <private/qguiapplication_p.h>
 # include <private/qsessionmanager_p.h>
 # include "qwindowssessionmanager.h"
 #endif
@@ -1025,6 +1025,12 @@ void QWindowsContext::handleFocusEvent(QtWindows::WindowsEventType et,
 {
     QWindow *nextActiveWindow = 0;
     if (et == QtWindows::FocusInEvent) {
+        QWindow *topWindow = QWindowsWindow::topLevelOf(platformWindow->window());
+        QWindow *modalWindow = 0;
+        if (QGuiApplicationPrivate::instance()->isWindowBlocked(topWindow, &modalWindow) && topWindow != modalWindow) {
+            modalWindow->requestActivate();
+            return;
+        }
         nextActiveWindow = platformWindow->window();
     } else {
         // Focus out: Is the next window known and different
diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index ee9bf9936c..db06525508 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -1016,17 +1016,17 @@ QWindow *QWindowsWindow::topLevelOf(QWindow *w)
     while (QWindow *parent = w->parent())
         w = parent;
 
-    const QWindowsWindow *ww = static_cast<const QWindowsWindow *>(w->handle());
-
-    // In case the topmost parent is embedded, find next ancestor using native methods
-    if (ww->isEmbedded(0)) {
-        HWND parentHWND = GetAncestor(ww->handle(), GA_PARENT);
-        const HWND desktopHwnd = GetDesktopWindow();
-        const QWindowsContext *ctx = QWindowsContext::instance();
-        while (parentHWND && parentHWND != desktopHwnd) {
-            if (QWindowsWindow *ancestor = ctx->findPlatformWindow(parentHWND))
-                return topLevelOf(ancestor->window());
-            parentHWND = GetAncestor(parentHWND, GA_PARENT);
+    if (const QPlatformWindow *handle = w->handle()) {
+        const QWindowsWindow *ww = static_cast<const QWindowsWindow *>(handle);
+        if (ww->isEmbedded(0)) {
+            HWND parentHWND = GetAncestor(ww->handle(), GA_PARENT);
+            const HWND desktopHwnd = GetDesktopWindow();
+            const QWindowsContext *ctx = QWindowsContext::instance();
+            while (parentHWND && parentHWND != desktopHwnd) {
+                if (QWindowsWindow *ancestor = ctx->findPlatformWindow(parentHWND))
+                    return topLevelOf(ancestor->window());
+                parentHWND = GetAncestor(parentHWND, GA_PARENT);
+            }
         }
     }
     return w;
diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 193e75c1d6..dbffd577c1 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -485,7 +485,7 @@ QXcbWindow::~QXcbWindow()
 void QXcbWindow::destroy()
 {
     if (connection()->focusWindow() == this)
-        connection()->setFocusWindow(0);
+        doFocusOut();
 
     if (m_syncCounter && m_usingSyncProtocol)
         Q_XCB_CALL(xcb_sync_destroy_counter(xcb_connection(), m_syncCounter));
@@ -671,6 +671,9 @@ void QXcbWindow::show()
 
     Q_XCB_CALL(xcb_map_window(xcb_connection(), m_window));
 
+    if (QGuiApplication::modalWindow() == window())
+        requestActivateWindow();
+
     m_screen->windowShown(this);
 
     connection()->sync();
@@ -694,6 +697,68 @@ void QXcbWindow::hide()
     m_mapped = false;
 }
 
+static QWindow *tlWindow(QWindow *window)
+{
+    if (window && window->parent())
+        return tlWindow(window->parent());
+    return window;
+}
+
+bool QXcbWindow::relayFocusToModalWindow() const
+{
+    QWindow *w = tlWindow(static_cast<QWindowPrivate *>(QObjectPrivate::get(window()))->eventReceiver());
+    QWindow *modal_window = 0;
+    if (QGuiApplicationPrivate::instance()->isWindowBlocked(w,&modal_window) && modal_window != w) {
+        modal_window->requestActivate();
+        connection()->flush();
+        return true;
+    }
+
+    return false;
+}
+
+void QXcbWindow::doFocusIn()
+{
+    if (relayFocusToModalWindow())
+        return;
+    QWindow *w = static_cast<QWindowPrivate *>(QObjectPrivate::get(window()))->eventReceiver();
+    connection()->setFocusWindow(static_cast<QXcbWindow *>(w->handle()));
+    QWindowSystemInterface::handleWindowActivated(w, Qt::ActiveWindowFocusReason);
+}
+
+static bool focusInPeeker(QXcbConnection *connection, xcb_generic_event_t *event)
+{
+    if (!event) {
+        // FocusIn event is not in the queue, proceed with FocusOut normally.
+        QWindowSystemInterface::handleWindowActivated(0, Qt::ActiveWindowFocusReason);
+        return true;
+    }
+    uint response_type = event->response_type & ~0x80;
+    if (response_type == XCB_FOCUS_IN)
+        return true;
+
+    /* We are also interested in XEMBED_FOCUS_IN events */
+    if (response_type == XCB_CLIENT_MESSAGE) {
+        xcb_client_message_event_t *cme = (xcb_client_message_event_t *)event;
+        if (cme->type == connection->atom(QXcbAtom::_XEMBED)
+            && cme->data.data32[1] == XEMBED_FOCUS_IN)
+            return true;
+    }
+
+    return false;
+}
+
+void QXcbWindow::doFocusOut()
+{
+    if (relayFocusToModalWindow())
+        return;
+    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.
+    connection()->addPeekFunc(focusInPeeker);
+}
+
 struct QtMotifWmHints {
     quint32 flags, functions, decorations;
     qint32 input_mode;
@@ -1514,6 +1579,8 @@ void QXcbWindow::handleClientMessageEvent(const xcb_client_message_event_t *even
             QWindowSystemInterface::handleCloseEvent(window());
         } else if (event->data.data32[0] == atom(QXcbAtom::WM_TAKE_FOCUS)) {
             connection()->setTime(event->data.data32[1]);
+            relayFocusToModalWindow();
+            return;
         } else if (event->data.data32[0] == atom(QXcbAtom::_NET_WM_PING)) {
             if (event->window == m_screen->root())
                 return;
@@ -1549,8 +1616,7 @@ void QXcbWindow::handleClientMessageEvent(const xcb_client_message_event_t *even
     } else if (event->type == atom(QXcbAtom::_XEMBED)) {
         handleXEmbedMessage(event);
     } else if (event->type == atom(QXcbAtom::_NET_ACTIVE_WINDOW)) {
-        connection()->setFocusWindow(this);
-        QWindowSystemInterface::handleWindowActivated(window(), Qt::ActiveWindowFocusReason);
+        doFocusIn();
     } else if (event->type == atom(QXcbAtom::MANAGER)
                || event->type == atom(QXcbAtom::_NET_WM_STATE)
                || event->type == atom(QXcbAtom::WM_CHANGE_STATE)) {
@@ -1865,41 +1931,13 @@ void QXcbWindow::handlePropertyNotifyEvent(const xcb_property_notify_event_t *ev
 
 void QXcbWindow::handleFocusInEvent(const xcb_focus_in_event_t *)
 {
-    QWindow *w = window();
-    w = static_cast<QWindowPrivate *>(QObjectPrivate::get(w))->eventReceiver();
-    connection()->setFocusWindow(static_cast<QXcbWindow *>(w->handle()));
-    QWindowSystemInterface::handleWindowActivated(w, Qt::ActiveWindowFocusReason);
+    doFocusIn();
 }
 
-static bool focusInPeeker(QXcbConnection *connection, xcb_generic_event_t *event)
-{
-    if (!event) {
-        // FocusIn event is not in the queue, proceed with FocusOut normally.
-        QWindowSystemInterface::handleWindowActivated(0, Qt::ActiveWindowFocusReason);
-        return true;
-    }
-    uint response_type = event->response_type & ~0x80;
-    if (response_type == XCB_FOCUS_IN)
-        return true;
-
-    /* We are also interested in XEMBED_FOCUS_IN events */
-    if (response_type == XCB_CLIENT_MESSAGE) {
-        xcb_client_message_event_t *cme = (xcb_client_message_event_t *)event;
-        if (cme->type == connection->atom(QXcbAtom::_XEMBED)
-            && cme->data.data32[1] == XEMBED_FOCUS_IN)
-            return true;
-    }
-
-    return false;
-}
 
 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.
-    connection()->addPeekFunc(focusInPeeker);
+    doFocusOut();
 }
 
 void QXcbWindow::updateSyncRequestCounter()
diff --git a/src/plugins/platforms/xcb/qxcbwindow.h b/src/plugins/platforms/xcb/qxcbwindow.h
index a90ad7b5ed..12d17023fb 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.h
+++ b/src/plugins/platforms/xcb/qxcbwindow.h
@@ -176,6 +176,10 @@ private:
     void show();
     void hide();
 
+    bool relayFocusToModalWindow() const;
+    void doFocusIn();
+    void doFocusOut();
+
     QXcbScreen *m_screen;
 
     xcb_window_t m_window;