xwayland: Use KWIN_SINGLETON to make DataBridge a singleton

For consistency sake, use the KWIN_SINGLETON macro in order to make the
DataBridge class a singleton.

xwl/databridge.cpp

@@ -33,11 +33,11 @@ namespace KWin
 namespace Xwl
 {
 
-static DataBridge *s_self = nullptr;
+KWIN_SINGLETON_FACTORY(DataBridge)
 
-DataBridge *DataBridge::self()
+void DataBridge::destroy()
 {
-    return s_self;
+    delete s_self;
 }
 
 DataBridge::DataBridge(QObject *parent)

xwl/databridge.h

@@ -9,6 +9,8 @@
 #ifndef KWIN_XWL_DATABRIDGE
 #define KWIN_XWL_DATABRIDGE
 
+#include "kwinglobals.h"
+
 #include <QAbstractNativeEventFilter>
 #include <QObject>
 #include <QPoint>
@@ -32,7 +34,6 @@ class Toplevel;
 
 namespace Xwl
 {
-class Xwayland;
 class Clipboard;
 class Dnd;
 enum class DragEventReply;
@@ -48,9 +49,8 @@ class DataBridge : public QObject, public QAbstractNativeEventFilter
     Q_OBJECT
 
 public:
-    static DataBridge *self();
+    static void destroy();
 
-    explicit DataBridge(QObject *parent = nullptr);
     ~DataBridge() override;
 
     DragEventReply dragMoveFilter(Toplevel *target, const QPoint &pos);
@@ -80,7 +80,7 @@ private:
     KWayland::Client::DataDevice *m_dataDevice = nullptr;
     KWaylandServer::DataDeviceInterface *m_dataDeviceInterface = nullptr;
 
-    Q_DISABLE_COPY(DataBridge)
+    KWIN_SINGLETON(DataBridge)
 };
 
 } // namespace Xwl

xwl/xwayland.cpp

@@ -152,8 +152,7 @@ void Xwayland::stop()
     // events will be dispatched before blocking; otherwise we will simply hang...
     uninstallSocketNotifier();
 
-    delete m_dataBridge;
-    m_dataBridge = nullptr;
+    DataBridge::destroy();
 
     destroyX11Connection();
 
@@ -321,7 +320,7 @@ void Xwayland::continueStartupWithX()
     KSelectionOwner owner("WM_S0", xcbConn, m_app->x11RootWindow());
     owner.claim(true);
 
-    m_dataBridge = new DataBridge;
+    DataBridge::create(this);
 
     auto env = m_app->processStartupEnvironment();
     env.insert(QStringLiteral("DISPLAY"), QString::fromUtf8(qgetenv("DISPLAY")));
@@ -334,10 +333,11 @@ void Xwayland::continueStartupWithX()
 
 DragEventReply Xwayland::dragMoveFilter(Toplevel *target, const QPoint &pos)
 {
-    if (!m_dataBridge) {
+    DataBridge *bridge = DataBridge::self();
+    if (!bridge) {
         return DragEventReply::Wayland;
     }
-    return m_dataBridge->dragMoveFilter(target, pos);
+    return bridge->dragMoveFilter(target, pos);
 }
 
 } // namespace Xwl

xwl/xwayland.h

@@ -21,7 +21,6 @@ class ApplicationWaylandAbstract;
 
 namespace Xwl
 {
-class DataBridge;
 
 class Xwayland : public XwaylandInterface
 {
@@ -93,7 +92,6 @@ private:
     int m_displayFileDescriptor = -1;
     int m_xcbConnectionFd = -1;
     QProcess *m_xwaylandProcess = nullptr;
-    DataBridge *m_dataBridge = nullptr;
     QSocketNotifier *m_socketNotifier = nullptr;
     ApplicationWaylandAbstract *m_app;