Make AbstractEglBackend a QObject

Summary:
Several of the subclasses are already derived from QObject.

The main reason is that the class should be moved out of KWin core in
order to move the OpenGL scene into a plugin. As Compositor calls into
the AbstractEglBackend to unbind the wayland display this creates a
problem which is easily solved by turning the AbstractEglBackend into a
QObject and connect to the signal emitted by the Compositor.

Test Plan: Compiles

Reviewers: #kwin, #plasma

Subscribers: plasma-devel, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D7669

abstract_egl_backend.cpp

@@ -18,6 +18,7 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #include "abstract_egl_backend.h"
+#include "composite.h"
 #include "egl_context_attribute_builder.h"
 #include "options.h"
 #include "platform.h"
@@ -54,17 +55,18 @@ eglQueryWaylandBufferWL_func eglQueryWaylandBufferWL = nullptr;
 #endif
 
 AbstractEglBackend::AbstractEglBackend()
-    : OpenGLBackend()
+    : QObject(nullptr)
+    , OpenGLBackend()
 {
+    connect(Compositor::self(), &Compositor::aboutToDestroy, this, &AbstractEglBackend::unbindWaylandDisplay);
 }
 
 AbstractEglBackend::~AbstractEglBackend() = default;
 
 void AbstractEglBackend::unbindWaylandDisplay()
 {
-    auto display = kwinApp()->platform()->sceneEglDisplay();
-    if (eglUnbindWaylandDisplayWL && display != EGL_NO_DISPLAY) {
-        eglUnbindWaylandDisplayWL(display, *(WaylandServer::self()->display()));
+    if (eglUnbindWaylandDisplayWL && m_display != EGL_NO_DISPLAY) {
+        eglUnbindWaylandDisplayWL(m_display, *(WaylandServer::self()->display()));
     }
 }
 

abstract_egl_backend.h

@@ -29,8 +29,9 @@ class QOpenGLFramebufferObject;
 namespace KWin
 {
 
-class KWIN_EXPORT AbstractEglBackend : public OpenGLBackend
+class KWIN_EXPORT AbstractEglBackend : public QObject, public OpenGLBackend
 {
+    Q_OBJECT
 public:
     virtual ~AbstractEglBackend();
     bool makeCurrent() override;
@@ -49,8 +50,6 @@ public:
         return m_config;
     }
 
-    static void unbindWaylandDisplay();
-
 protected:
     AbstractEglBackend();
     void setEglDisplay(const EGLDisplay &display);
@@ -69,6 +68,8 @@ protected:
     bool createContext();
 
 private:
+    void unbindWaylandDisplay();
+
     EGLDisplay m_display = EGL_NO_DISPLAY;
     EGLSurface m_surface = EGL_NO_SURFACE;
     EGLContext m_context = EGL_NO_CONTEXT;

composite.cpp

@@ -19,7 +19,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #include "composite.h"
 
-#include "abstract_egl_backend.h"
 #include "dbusinterface.h"
 #include "utils.h"
 #include <QTextStream>
@@ -146,7 +145,6 @@ Compositor::Compositor(QObject* workspace)
 Compositor::~Compositor()
 {
     emit aboutToDestroy();
-    AbstractEglBackend::unbindWaylandDisplay();
     finish();
     deleteUnusedSupportProperties();
     delete cm_selection;

plugins/platforms/drm/egl_gbm_backend.cpp

@@ -36,8 +36,7 @@ namespace KWin
 {
 
 EglGbmBackend::EglGbmBackend(DrmBackend *b)
-    : QObject(NULL)
-    , AbstractEglBackend()
+    : AbstractEglBackend()
     , m_backend(b)
 {
     // Egl is always direct rendering

plugins/platforms/drm/egl_gbm_backend.h

@@ -33,7 +33,7 @@ class DrmOutput;
 /**
  * @brief OpenGL Backend using Egl on a GBM surface.
  **/
-class EglGbmBackend : public QObject, public AbstractEglBackend
+class EglGbmBackend : public AbstractEglBackend
 {
     Q_OBJECT
 public:

plugins/platforms/virtual/egl_gbm_backend.cpp

@@ -42,8 +42,7 @@ namespace KWin
 {
 
 EglGbmBackend::EglGbmBackend(VirtualBackend *b)
-    : QObject(nullptr)
-    , AbstractEglBackend()
+    : AbstractEglBackend()
     , m_backend(b)
 {
     // Egl is always direct rendering

plugins/platforms/virtual/egl_gbm_backend.h

@@ -31,9 +31,8 @@ class GLRenderTarget;
 /**
  * @brief OpenGL Backend using Egl on a GBM surface.
  **/
-class EglGbmBackend : public QObject, public AbstractEglBackend
+class EglGbmBackend : public AbstractEglBackend
 {
-    Q_OBJECT
 public:
     EglGbmBackend(VirtualBackend *b);
     virtual ~EglGbmBackend();

plugins/platforms/wayland/egl_wayland_backend.cpp

@@ -39,8 +39,7 @@ namespace KWin
 {
 
 EglWaylandBackend::EglWaylandBackend(Wayland::WaylandBackend *b)
-    : QObject(NULL)
-    , AbstractEglBackend()
+    : AbstractEglBackend()
     , m_bufferAge(0)
     , m_wayland(b)
     , m_overlay(NULL)

plugins/platforms/wayland/egl_wayland_backend.h

@@ -47,7 +47,7 @@ namespace Wayland {
  * repaints, which is obviously not optimal. Best solution is probably to go for buffer_age extension
  * and make it the only available solution next to fullscreen repaints.
  **/
-class EglWaylandBackend : public QObject, public AbstractEglBackend
+class EglWaylandBackend : public AbstractEglBackend
 {
     Q_OBJECT
 public: