[platforms/wayland] Use XdgShell if available and prefer it

Summary:
With this change the Wayland platform plugin uses the XdgShell to
create the window if available. This allows to close the window and
thus quit the nested kwin_wayland properly.

Reviewers: #kwin, #plasma_on_wayland

Subscribers: plasma-devel, kwin

Tags: #plasma_on_wayland, #kwin

Differential Revision: https://phabricator.kde.org/D2201

plugins/platforms/wayland/wayland_backend.cpp

@@ -45,6 +45,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <KWayland/Client/shm_pool.h>
 #include <KWayland/Client/surface.h>
 #include <KWayland/Client/touch.h>
+#include <KWayland/Client/xdgshell.h>
 #include <KWayland/Server/buffer_interface.h>
 #include <KWayland/Server/seat_interface.h>
 #include <KWayland/Server/surface_interface.h>
@@ -281,12 +282,18 @@ WaylandBackend::WaylandBackend(QObject *parent)
 
 WaylandBackend::~WaylandBackend()
 {
+    if (m_xdgShellSurface) {
+        m_xdgShellSurface->release();
+    }
     if (m_shellSurface) {
         m_shellSurface->release();
     }
     if (m_surface) {
         m_surface->release();
     }
+    if (m_xdgShell) {
+        m_xdgShell->release();
+    }
     m_shell->release();
     m_compositor->release();
     m_registry->release();
@@ -361,6 +368,11 @@ void WaylandBackend::initConnection()
             emit systemCompositorDied();
             m_seat.reset();
             m_shm->destroy();
+            if (m_xdgShellSurface) {
+                m_xdgShellSurface->destroy();
+                delete m_xdgShellSurface;
+                m_xdgShellSurface = nullptr;
+            }
             if (m_shellSurface) {
                 m_shellSurface->destroy();
                 delete m_shellSurface;
@@ -374,6 +386,9 @@ void WaylandBackend::initConnection()
             if (m_shell) {
                 m_shell->destroy();
             }
+            if (m_xdgShell) {
+                m_xdgShell->destroy();
+            }
             m_compositor->destroy();
             m_registry->destroy();
             m_eventQueue->destroy();
@@ -414,21 +429,41 @@ void WaylandBackend::createSurface()
     if (m_seat) {
         m_seat->setInstallCursor(true);
     }
+    // check for xdg shell
+    auto xdgIface = m_registry->interface(Registry::Interface::XdgShellUnstableV5);
+    if (xdgIface.name != 0) {
+        m_xdgShell = m_registry->createXdgShell(xdgIface.name, xdgIface.version, this);
+        if (m_xdgShell && m_xdgShell->isValid()) {
+            m_xdgShellSurface = m_xdgShell->createSurface(m_surface, this);
+            connect(m_xdgShellSurface, &XdgShellSurface::closeRequested, qApp, &QCoreApplication::quit);
+            setupSurface(m_xdgShellSurface);
+            return;
+        }
+    }
     if (m_shell->isValid()) {
         m_shellSurface = m_shell->createSurface(m_surface, this);
-        connect(m_shellSurface, &ShellSurface::sizeChanged, this, &WaylandBackend::shellSurfaceSizeChanged);
-        m_shellSurface->setSize(initialWindowSize());
+        setupSurface(m_shellSurface);
         m_shellSurface->setToplevel();
-        setReady(true);
-        emit screensQueried();
     }
 }
 
+template <class T>
+void WaylandBackend::setupSurface(T *surface)
+{
+    connect(surface, &T::sizeChanged, this, &WaylandBackend::shellSurfaceSizeChanged);
+    surface->setSize(initialWindowSize());
+    setReady(true);
+    emit screensQueried();
+}
+
 QSize WaylandBackend::shellSurfaceSize() const
 {
     if (m_shellSurface) {
         return m_shellSurface->size();
     }
+    if (m_xdgShellSurface) {
+        return m_xdgShellSurface->size();
+    }
     return QSize();
 }
 

plugins/platforms/wayland/wayland_backend.h

@@ -53,6 +53,8 @@ class Shell;
 class ShellSurface;
 class Surface;
 class Touch;
+class XdgShell;
+class XdgShellSurface;
 }
 }
 
@@ -132,6 +134,8 @@ Q_SIGNALS:
 private:
     void initConnection();
     void createSurface();
+    template <class T>
+    void setupSurface(T *surface);
     wl_display *m_display;
     KWayland::Client::EventQueue *m_eventQueue;
     KWayland::Client::Registry *m_registry;
@@ -139,6 +143,8 @@ private:
     KWayland::Client::Shell *m_shell;
     KWayland::Client::Surface *m_surface;
     KWayland::Client::ShellSurface *m_shellSurface;
+    KWayland::Client::XdgShell *m_xdgShell = nullptr;
+    KWayland::Client::XdgShellSurface *m_xdgShellSurface = nullptr;
     QScopedPointer<WaylandSeat> m_seat;
     KWayland::Client::ShmPool *m_shm;
     KWayland::Client::ConnectionThread *m_connectionThreadObject;