client: Implement dialog-v1 protocol

Allows to mark windows as modal dialogs.

Change-Id: Ie4999552933e02fc473e621e7cc5e3f2928c0adb
Reviewed-by: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

13 files changed, 363 insertions, 5 deletions

diff --git a/src/3rdparty/protocol/qt_attribution.json b/src/3rdparty/protocol/qt_attribution.json
index 33a4f17c4..6ced46a2b 100644
--- a/src/3rdparty/protocol/qt_attribution.json
+++ b/src/3rdparty/protocol/qt_attribution.json
@@ -336,5 +336,22 @@
         "License": "MIT License",
         "LicenseFile": "MIT_LICENSE.txt",
         "Copyright": "Copyright © 2022 Kenny Levinsen"
+     },
+
+    {
+        "Id": "xdg-dialog-v1",
+        "Name": "Wayland Dialog Protocol",
+        "QDocModule": "qtwaylandcompositor",
+        "QtUsage": "Used in the Qt Wayland platform plugin",
+        "Files": "xdg-dialog-v1.xml",
+
+        "Description": "Register toplevel as dialogs",
+        "Homepage": "https://wayland.freedesktop.org",
+        "Version": "1",
+        "DownloadLocation": "",
+        "LicenseId": "MIT",
+        "License": "MIT License",
+        "LicenseFile": "MIT_LICENSE.txt",
+        "Copyright": "Copyright © 2023 Carlos Garnacho"
      }
 ]
diff --git a/src/3rdparty/protocol/xdg-dialog-v1.xml b/src/3rdparty/protocol/xdg-dialog-v1.xml
new file mode 100644
index 000000000..ed2141132
--- /dev/null
+++ b/src/3rdparty/protocol/xdg-dialog-v1.xml
@@ -0,0 +1,110 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="dialog_v1">
+  <copyright>
+    Copyright © 2023 Carlos Garnacho
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice (including the next
+    paragraph) shall be included in all copies or substantial portions of the
+    Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
+  </copyright>
+
+  <interface name="xdg_wm_dialog_v1" version="1">
+    <description summary="create dialogs related to other toplevels">
+      The xdg_wm_dialog_v1 interface is exposed as a global object allowing
+      to register surfaces with a xdg_toplevel role as "dialogs" relative to
+      another toplevel.
+
+      The compositor may let this relation influence how the surface is
+      placed, displayed or interacted with.
+
+      Warning! The protocol described in this file is currently in the testing
+      phase. Backward compatible changes may be added together with the
+      corresponding interface version bump. Backward incompatible changes can
+      only be done by creating a new major version of the extension.
+    </description>
+
+    <enum name="error">
+      <entry name="already_used" value="0"
+             summary="the xdg_toplevel object has already been used to create a xdg_dialog_v1"/>
+    </enum>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the dialog manager object">
+        Destroys the xdg_wm_dialog_v1 object. This does not affect
+        the xdg_dialog_v1 objects generated through it.
+      </description>
+    </request>
+
+    <request name="get_xdg_dialog">
+      <description summary="create a dialog object">
+        Creates a xdg_dialog_v1 object for the given toplevel. See the interface
+        description for more details.
+
+	Compositors must raise an already_used error if clients attempt to
+	create multiple xdg_dialog_v1 objects for the same xdg_toplevel.
+      </description>
+      <arg name="id" type="new_id" interface="xdg_dialog_v1"/>
+      <arg name="toplevel" type="object" interface="xdg_toplevel"/>
+    </request>
+  </interface>
+
+  <interface name="xdg_dialog_v1" version="1">
+    <description summary="dialog object">
+      A xdg_dialog_v1 object is an ancillary object tied to a xdg_toplevel. Its
+      purpose is hinting the compositor that the toplevel is a "dialog" (e.g. a
+      temporary window) relative to another toplevel (see
+      xdg_toplevel.set_parent). If the xdg_toplevel is destroyed, the xdg_dialog_v1
+      becomes inert.
+
+      Through this object, the client may provide additional hints about
+      the purpose of the secondary toplevel. This interface has no effect
+      on toplevels that are not attached to a parent toplevel.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the dialog object">
+        Destroys the xdg_dialog_v1 object. If this object is destroyed
+        before the related xdg_toplevel, the compositor should unapply its
+        effects.
+      </description>
+    </request>
+
+    <request name="set_modal">
+      <description summary="mark dialog as modal">
+        Hints that the dialog has "modal" behavior. Modal dialogs typically
+        require to be fully addressed by the user (i.e. closed) before resuming
+        interaction with the parent toplevel, and may require a distinct
+        presentation.
+
+        Clients must implement the logic to filter events in the parent
+        toplevel on their own.
+
+        Compositors may choose any policy in event delivery to the parent
+        toplevel, from delivering all events unfiltered to using them for
+        internal consumption.
+      </description>
+    </request>
+
+    <request name="unset_modal">
+      <description summary="mark dialog as not modal">
+        Drops the hint that this dialog has "modal" behavior. See
+        xdg_dialog_v1.set_modal for more details.
+      </description>
+    </request>
+  </interface>
+</protocol>
diff --git a/src/plugins/shellintegration/xdg-shell/CMakeLists.txt b/src/plugins/shellintegration/xdg-shell/CMakeLists.txt
index a33a28a7e..af5a97fee 100644
--- a/src/plugins/shellintegration/xdg-shell/CMakeLists.txt
+++ b/src/plugins/shellintegration/xdg-shell/CMakeLists.txt
@@ -17,6 +17,7 @@ qt_internal_add_plugin(QWaylandXdgShellIntegrationPlugin
         qwaylandxdgshell.cpp qwaylandxdgshell_p.h
         qwaylandxdgshellintegration.cpp qwaylandxdgshellintegration_p.h
         qwaylandxdgexporterv2.cpp qwaylandxdgexporterv2_p.h
+        qwaylandxdgdialogv1.cpp qwaylandxdgdialogv1_p.h
     LIBRARIES
         Qt::Core
         Qt::Gui
@@ -31,6 +32,7 @@ qt6_generate_wayland_protocol_client_sources(QWaylandXdgShellIntegrationPlugin
         ${CMAKE_CURRENT_SOURCE_DIR}/../../../3rdparty/protocol/xdg-shell.xml
         ${CMAKE_CURRENT_SOURCE_DIR}/../../../3rdparty/protocol/xdg-activation-v1.xml
         ${CMAKE_CURRENT_SOURCE_DIR}/../../../3rdparty/protocol/xdg-foreign-unstable-v2.xml
+        ${CMAKE_CURRENT_SOURCE_DIR}/../../../3rdparty/protocol/xdg-dialog-v1.xml
 )
 
 #### Keys ignored in scope 1:.:.:xdg-shell.pro:<TRUE>:
diff --git a/src/plugins/shellintegration/xdg-shell/qwaylandxdgdialogv1.cpp b/src/plugins/shellintegration/xdg-shell/qwaylandxdgdialogv1.cpp
new file mode 100644
index 000000000..abf674623
--- /dev/null
+++ b/src/plugins/shellintegration/xdg-shell/qwaylandxdgdialogv1.cpp
@@ -0,0 +1,33 @@
+// Copyright (C) 2023 David Reondo <kde@david-redondo.de>
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include "qwaylandxdgdialogv1_p.h"
+
+QT_BEGIN_NAMESPACE
+
+namespace QtWaylandClient {
+
+QWaylandXdgDialogV1::QWaylandXdgDialogV1(::xdg_dialog_v1 *object) : xdg_dialog_v1(object) { }
+
+QWaylandXdgDialogV1::~QWaylandXdgDialogV1()
+{
+    xdg_dialog_v1_destroy(object());
+}
+
+QWaylandXdgDialogWmV1::QWaylandXdgDialogWmV1(wl_registry *registry, uint32_t id, int version)
+    : xdg_wm_dialog_v1(registry, id, version)
+{
+}
+
+QWaylandXdgDialogWmV1::~QWaylandXdgDialogWmV1()
+{
+    destroy();
+}
+QWaylandXdgDialogV1 *QWaylandXdgDialogWmV1::getDialog(xdg_toplevel *toplevel)
+{
+    return new QWaylandXdgDialogV1(get_xdg_dialog(toplevel));
+}
+
+} // namespace QtWaylandClient
+
+QT_END_NAMESPACE
diff --git a/src/plugins/shellintegration/xdg-shell/qwaylandxdgdialogv1_p.h b/src/plugins/shellintegration/xdg-shell/qwaylandxdgdialogv1_p.h
new file mode 100644
index 000000000..f5465a63e
--- /dev/null
+++ b/src/plugins/shellintegration/xdg-shell/qwaylandxdgdialogv1_p.h
@@ -0,0 +1,32 @@
+// Copyright (C) 2022 David Reondo <kde@david-redondo.de>
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QWAYLANDDIALOGV1_P_H
+#define QWAYLANDDIALOGV1_P_H
+
+#include <qwayland-xdg-dialog-v1.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace QtWaylandClient {
+
+class QWaylandXdgDialogV1 : public QtWayland::xdg_dialog_v1
+{
+public:
+    QWaylandXdgDialogV1(::xdg_dialog_v1 *object);
+    ~QWaylandXdgDialogV1() override;
+};
+
+class QWaylandXdgDialogWmV1 : public QtWayland::xdg_wm_dialog_v1
+{
+public:
+    QWaylandXdgDialogWmV1(wl_registry *registry, uint32_t id, int version);
+    ~QWaylandXdgDialogWmV1() override;
+    QWaylandXdgDialogV1 *getDialog(xdg_toplevel *toplevel);
+};
+
+} // namespace QtWaylandClient
+
+QT_END_NAMESPACE
+
+#endif
diff --git a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
index 498710beb..d338f7475 100644
--- a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
+++ b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
@@ -6,6 +6,7 @@
 #include "qwaylandxdgshell_p.h"
 
 #include "qwaylandxdgexporterv2_p.h"
+#include "qwaylandxdgdialogv1_p.h"
 
 #include <QtWaylandClient/private/qwaylanddisplay_p.h>
 #include <QtWaylandClient/private/qwaylandwindow_p.h>
@@ -32,6 +33,16 @@ QWaylandXdgSurface::Toplevel::Toplevel(QWaylandXdgSurface *xdgSurface)
     }
     requestWindowStates(window->windowStates());
     requestWindowFlags(window->flags());
+    if (auto transientParent = xdgSurface->window()->transientParent()) {
+        if (auto parentSurface =
+                    qobject_cast<QWaylandXdgSurface *>(transientParent->shellSurface())) {
+            set_parent(parentSurface->m_toplevel->object());
+            if (window->modality() != Qt::NonModal && m_xdgSurface->m_shell->m_xdgDialogWm) {
+                m_xdgDialog.reset(m_xdgSurface->m_shell->m_xdgDialogWm->getDialog(object()));
+                m_xdgDialog->set_modal();
+            }
+        }
+    }
 }
 
 QWaylandXdgSurface::Toplevel::~Toplevel()
@@ -296,11 +307,6 @@ QWaylandXdgSurface::QWaylandXdgSurface(QWaylandXdgShell *shell, ::xdg_surface *s
         setGrabPopup(transientParent, display->lastInputDevice(), display->lastInputSerial());
     } else {
         setToplevel();
-        if (transientParent) {
-            auto parentXdgSurface = qobject_cast<QWaylandXdgSurface *>(transientParent->shellSurface());
-            if (parentXdgSurface)
-                m_toplevel->set_parent(parentXdgSurface->m_toplevel->object());
-        }
     }
     setSizeHints();
 }
@@ -752,6 +758,10 @@ void QWaylandXdgShell::handleRegistryGlobal(void *data, wl_registry *registry, u
     if (interface == QLatin1String(QWaylandXdgExporterV2::interface()->name)) {
         xdgShell->m_xdgExporter.reset(new QWaylandXdgExporterV2(registry, id, version));
     }
+
+    if (interface == QLatin1String(QWaylandXdgDialogWmV1::interface()->name)) {
+        xdgShell->m_xdgDialogWm.reset(new QWaylandXdgDialogWmV1(registry, id, version));
+    }
 }
 
 }
diff --git a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h
index 0310706fd..22a207a25 100644
--- a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h
+++ b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h
@@ -39,6 +39,8 @@ class QWaylandInputDevice;
 class QWaylandXdgShell;
 class QWaylandXdgExportedV2;
 class QWaylandXdgExporterV2;
+class QWaylandXdgDialogWmV1;
+class QWaylandXdgDialogV1;
 
 class Q_WAYLANDCLIENT_EXPORT QWaylandXdgSurface : public QWaylandShellSurface, public QtWayland::xdg_surface
 {
@@ -109,6 +111,7 @@ private:
         QWaylandXdgSurface *m_xdgSurface = nullptr;
         QWaylandXdgToplevelDecorationV1 *m_decoration = nullptr;
         QScopedPointer<QWaylandXdgExportedV2> m_exported;
+        QScopedPointer<QWaylandXdgDialogV1> m_xdgDialog;
     };
 
     class Popup : public QtWayland::xdg_popup {
@@ -171,6 +174,7 @@ private:
     QScopedPointer<QWaylandXdgDecorationManagerV1> m_xdgDecorationManager;
     QScopedPointer<QWaylandXdgActivationV1> m_xdgActivation;
     QScopedPointer<QWaylandXdgExporterV2> m_xdgExporter;
+    QScopedPointer<QWaylandXdgDialogWmV1> m_xdgDialogWm;
 
     friend class QWaylandXdgSurface;
 };
diff --git a/tests/auto/client/shared/CMakeLists.txt b/tests/auto/client/shared/CMakeLists.txt
index ee81b4d68..1d64f2956 100644
--- a/tests/auto/client/shared/CMakeLists.txt
+++ b/tests/auto/client/shared/CMakeLists.txt
@@ -16,6 +16,7 @@ qt_manual_moc(moc_files
     textinput.h
     qttextinput.h
     viewport.h
+    xdgdialog.h
     xdgoutputv1.h
     xdgshell.h
 )
@@ -33,6 +34,7 @@ add_library(SharedClientTest
         qttextinput.cpp qttextinput.h
         xdgoutputv1.cpp xdgoutputv1.h
         xdgshell.cpp xdgshell.h
+        xdgdialog.cpp xdgdialog.h
         viewport.cpp viewport.h
         ${moc_files}
 )
@@ -50,6 +52,7 @@ qt6_generate_wayland_protocol_server_sources(SharedClientTest
         ${PROJECT_SOURCE_DIR}/src/3rdparty/protocol/viewporter.xml
         ${PROJECT_SOURCE_DIR}/src/3rdparty/protocol/wayland.xml
         ${PROJECT_SOURCE_DIR}/src/3rdparty/protocol/xdg-decoration-unstable-v1.xml
+        ${PROJECT_SOURCE_DIR}/src/3rdparty/protocol/xdg-dialog-v1.xml
         ${PROJECT_SOURCE_DIR}/src/3rdparty/protocol/xdg-output-unstable-v1.xml
         ${PROJECT_SOURCE_DIR}/src/3rdparty/protocol/xdg-shell.xml
 )
diff --git a/tests/auto/client/shared/mockcompositor.cpp b/tests/auto/client/shared/mockcompositor.cpp
index 571117d6b..d6eb560c9 100644
--- a/tests/auto/client/shared/mockcompositor.cpp
+++ b/tests/auto/client/shared/mockcompositor.cpp
@@ -23,6 +23,7 @@ DefaultCompositor::DefaultCompositor(CompositorType t, int socketFd)
         add<XdgWmBase>();
         add<FractionalScaleManager>();
         add<Viewporter>();
+        add<XdgWmDialog>();
 
         switch (m_type) {
         case CompositorType::Default:
diff --git a/tests/auto/client/shared/mockcompositor.h b/tests/auto/client/shared/mockcompositor.h
index 268f77680..7cde39954 100644
--- a/tests/auto/client/shared/mockcompositor.h
+++ b/tests/auto/client/shared/mockcompositor.h
@@ -13,6 +13,7 @@
 #include "xdgshell.h"
 #include "viewport.h"
 #include "fractionalscalev1.h"
+#include "xdgdialog.h"
 
 #include <QtGui/QGuiApplication>
 
@@ -50,6 +51,7 @@ public:
     IviSurface *iviSurface(int i = 0) { return get<IviApplication>()->m_iviSurfaces.value(i, nullptr); }
     FractionalScale *fractionalScale(int i = 0) {return get<FractionalScaleManager>()->m_fractionalScales.value(i, nullptr); }
     Viewport *viewport(int i = 0) {return get<Viewporter>()->m_viewports.value(i, nullptr); }
+    XdgDialog *xdgDialog(int i = 0) { return get<XdgWmDialog>()->m_dialogs.value(i, nullptr); }
 
     uint sendXdgShellPing();
     void xdgPingAndWaitForPong();
diff --git a/tests/auto/client/shared/xdgdialog.cpp b/tests/auto/client/shared/xdgdialog.cpp
new file mode 100644
index 000000000..065a0fd3c
--- /dev/null
+++ b/tests/auto/client/shared/xdgdialog.cpp
@@ -0,0 +1,59 @@
+// Copyright (C) 2024 David Redondo <kde@david-redondo.de>
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+#include "xdgdialog.h"
+
+#include "xdgshell.h"
+
+namespace MockCompositor {
+
+XdgDialog::XdgDialog(XdgWmDialog *wm, XdgToplevel *toplevel, wl_client *client, int id, int version)
+    : QtWaylandServer::xdg_dialog_v1(client, id, version),
+      toplevel(toplevel),
+      modal(false),
+      m_wm(wm)
+{
+}
+
+void XdgDialog::xdg_dialog_v1_set_modal(Resource *resource)
+{
+    Q_UNUSED(resource)
+    modal = true;
+}
+
+void XdgDialog::xdg_dialog_v1_unset_modal(Resource *resource)
+{
+    Q_UNUSED(resource)
+    modal = false;
+}
+
+void XdgDialog::xdg_dialog_v1_destroy(Resource *resource)
+{
+    wl_resource_destroy(resource->handle);
+}
+
+void XdgDialog::xdg_dialog_v1_destroy_resource(Resource *resource)
+{
+    Q_UNUSED(resource)
+    m_wm->m_dialogs.removeOne(this);
+    delete this;
+}
+
+XdgWmDialog::XdgWmDialog(CoreCompositor *compositor, int version)
+    : QtWaylandServer::xdg_wm_dialog_v1(compositor->m_display, version)
+{
+}
+
+void XdgWmDialog::xdg_wm_dialog_v1_destroy(Resource *resource)
+{
+    wl_resource_destroy(resource->handle);
+}
+
+void XdgWmDialog::xdg_wm_dialog_v1_get_xdg_dialog(Resource *resource, uint32_t id,
+                                                  struct ::wl_resource *toplevel)
+{
+    auto *t = fromResource<XdgToplevel>(toplevel);
+    auto *dialog = new XdgDialog(this, t, resource->client(), id, resource->version());
+    m_dialogs.push_back(dialog);
+}
+
+} // namespace MockCompositor
diff --git a/tests/auto/client/shared/xdgdialog.h b/tests/auto/client/shared/xdgdialog.h
new file mode 100644
index 000000000..6b4ccd0bc
--- /dev/null
+++ b/tests/auto/client/shared/xdgdialog.h
@@ -0,0 +1,49 @@
+// Copyright (C) 2024 David Redondo <kde@david-redondo.de>
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#ifndef MOCKCOMPOSITOR_XDG_DIALOG_H
+#define MOCKCOMPOSITOR_XDG_DIALOG_H
+
+#include "corecompositor.h"
+#include <qwayland-server-xdg-dialog-v1.h>
+
+namespace MockCompositor {
+
+class XdgToplevel;
+class XdgWmDialog;
+
+class XdgDialog : public QtWaylandServer::xdg_dialog_v1
+{
+public:
+    explicit XdgDialog(XdgWmDialog *wm, XdgToplevel *toplevel, wl_client *client, int id,
+                       int version);
+    XdgToplevel *toplevel;
+    bool modal;
+
+protected:
+    void xdg_dialog_v1_set_modal(Resource *resource) override;
+    void xdg_dialog_v1_unset_modal(Resource *resource) override;
+    void xdg_dialog_v1_destroy(Resource *resource) override;
+    void xdg_dialog_v1_destroy_resource(Resource *resource) override;
+
+private:
+    XdgWmDialog *m_wm;
+};
+
+class XdgWmDialog : public Global, public QtWaylandServer::xdg_wm_dialog_v1
+{
+    Q_OBJECT
+public:
+    explicit XdgWmDialog(CoreCompositor *compositor, int version = 1);
+    ~XdgWmDialog() = default;
+    QList<XdgDialog *> m_dialogs;
+
+protected:
+    void xdg_wm_dialog_v1_destroy(Resource *resource) override;
+    void xdg_wm_dialog_v1_get_xdg_dialog(Resource *resource, uint32_t id,
+                                         struct ::wl_resource *toplevel) override;
+};
+
+} // namespace MockCompositor
+
+#endif
diff --git a/tests/auto/client/xdgshell/tst_xdgshell.cpp b/tests/auto/client/xdgshell/tst_xdgshell.cpp
index a3e96d444..f222165e9 100644
--- a/tests/auto/client/xdgshell/tst_xdgshell.cpp
+++ b/tests/auto/client/xdgshell/tst_xdgshell.cpp
@@ -34,6 +34,7 @@ private slots:
     void nativeResources();
     void suspended();
     void initiallySuspended();
+    void modality();
 };
 
 void tst_xdgshell::init()
@@ -769,5 +770,40 @@ void tst_xdgshell::initiallySuspended()
     QVERIFY(!window.isExposed());
 }
 
+void tst_xdgshell::modality()
+{
+    QRasterWindow parent;
+    parent.resize(400, 320);
+    parent.show();
+
+    QRasterWindow child;
+    child.resize(400, 320);
+    child.setTransientParent(&parent);
+    child.show();
+    QCOMPOSITOR_TRY_VERIFY(xdgToplevel(1));
+    QCOMPOSITOR_VERIFY(!xdgDialog());
+
+    child.hide();
+    child.setModality(Qt::WindowModal);
+    child.show();
+    QCOMPOSITOR_TRY_VERIFY(xdgDialog());
+    QCOMPOSITOR_VERIFY(xdgDialog()->modal);
+
+    child.hide();
+    QCOMPOSITOR_TRY_VERIFY(!xdgDialog());
+
+    child.setModality(Qt::ApplicationModal);
+    child.show();
+    QCOMPOSITOR_TRY_VERIFY(xdgDialog());
+    QCOMPOSITOR_VERIFY(xdgDialog()->modal);
+
+    child.hide();
+    QCOMPOSITOR_TRY_VERIFY(!xdgDialog());
+
+    child.show();
+    child.setModality(Qt::NonModal);
+    QCOMPOSITOR_TRY_VERIFY(!xdgDialog());
+}
+
 QCOMPOSITOR_TEST_MAIN(tst_xdgshell)
 #include "tst_xdgshell.moc"