Introduce AbstractClient::destroyClient()

Summary:
The new method provides a generic way for destructing clients. Notice
that we can't just delete clients because we may need to discard
temporary window rules, which is usually done in destroyClient().

Test Plan: Compiles.

Reviewers: #kwin, davidedmundson

Reviewed By: #kwin, davidedmundson

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D27821

abstract_client.h

@@ -787,6 +787,7 @@ public:
      * Implementing subclasses can perform a windowing system solution for terminating.
      */
     virtual void killWindow() = 0;
+    virtual void destroyClient() = 0;
 
     enum class SameApplicationCheck {
         RelaxedForActive = 1 << 0,

internal_client.h

@@ -81,8 +81,8 @@ public:
     void updateDecoration(bool check_workspace_pos, bool force = false) override;
     void updateColorScheme() override;
     void showOnScreenEdge() override;
+    void destroyClient() override;
 
-    void destroyClient();
     void present(const QSharedPointer<QOpenGLFramebufferObject> fbo);
     void present(const QImage &image, const QRegion &damage);
     QWindow *internalWindow() const;

workspace.cpp

@@ -56,7 +56,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "unmanaged.h"
 #include "useractions.h"
 #include "virtualdesktops.h"
-#include "xdgshellclient.h"
 #include "was_user_interaction_x11_filter.h"
 #include "wayland_server.h"
 #include "xcbutils.h"
@@ -473,12 +472,9 @@ Workspace::~Workspace()
     X11Client::cleanupX11();
 
     if (waylandServer()) {
-        // TODO: Introduce AbstractClient::destroy().
         const QList<AbstractClient *> shellClients = waylandServer()->clients();
         for (AbstractClient *client : shellClients) {
-            if (XdgShellClient *shellClient = qobject_cast<XdgShellClient *>(client)) {
-                shellClient->destroyClient();
-            }
+            client->destroyClient();
         }
     }
 

x11client.h

@@ -129,7 +129,7 @@ public:
 
     bool manage(xcb_window_t w, bool isMapped);
     void releaseWindow(bool on_shutdown = false);
-    void destroyClient();
+    void destroyClient() override;
 
     QStringList activities() const override;
     void setOnActivity(const QString &activity, bool enable);

xdgshellclient.h

@@ -121,6 +121,7 @@ public:
     void killWindow() override;
     bool isLocalhost() const override;
     bool supportsWindowRules() const override;
+    void destroyClient() override;
 
     void installPlasmaShellSurface(KWayland::Server::PlasmaShellSurfaceInterface *surface);
     void installServerSideDecoration(KWayland::Server::ServerSideDecorationInterface *decoration);
@@ -170,7 +171,6 @@ private:
      */
     void finishInit();
     void createDecoration(const QRect &oldgeom);
-    void destroyClient();
     void createWindowId();
     void updateIcon();
     bool shouldExposeToWindowManagement();