Add QML api for client side extension.

This makes it simple to use client-side extensions in QML. The only
thing that the user needs to do is register the extension class using
qmlRegisterType() and the use the extension in QML.

Also adds simple QML example which uses client-side extension.

Change-Id: I2db99861d97c7bca5cfdbf86ba3a8ccc50fb24b0
Reviewed-by: Giulio Camuffo <giulio.camuffo@kdab.com>

src/plugins/platforms/wayland/global/qwaylandclientextension.cpp

@@ -38,6 +38,8 @@
 #include "qwaylandclientextension_p.h"
 #include <QtWaylandClient/private/qwaylanddisplay_p.h>
 #include <QtWaylandClient/private/qwaylandintegration_p.h>
+#include <QtGui/QGuiApplication>
+#include <QtGui/qpa/qplatformnativeinterface.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -45,11 +47,22 @@ namespace QtWaylandClient {
 
 QWaylandClientExtensionPrivate::QWaylandClientExtensionPrivate()
     : QObjectPrivate()
-    , waylandIntegration(new QWaylandIntegration())
+    , waylandIntegration(NULL)
     , version(-1)
+    , active(false)
 {
-    QtWaylandClient::QWaylandDisplay *waylandDisplay = waylandIntegration->display();
-    struct ::wl_registry *registry = wl_display_get_registry(waylandDisplay->wl_display());
+    // Keep the possibility to use a custom waylandIntegration as a plugin,
+    // but also add the possibility to run it as a QML component.
+    struct ::wl_display *waylandDisplay = NULL;
+    if (QGuiApplication::platformNativeInterface()) {
+        waylandDisplay = static_cast<struct ::wl_display*>(QGuiApplication::platformNativeInterface()->nativeResourceForIntegration("wl_display"));
+    } else {
+        waylandIntegration = new QWaylandIntegration();
+        waylandDisplay = waylandIntegration->display()->wl_display();
+    }
+
+    Q_ASSERT(waylandDisplay);
+    struct ::wl_registry *registry = wl_display_get_registry(waylandDisplay);
     QtWayland::wl_registry::init(registry);
 }
 
@@ -59,6 +72,8 @@ void QWaylandClientExtensionPrivate::registry_global(uint32_t id, const QString
     if (interfaceName == QLatin1String(q->extensionInterface()->name)) {
         struct ::wl_registry *registry = static_cast<struct ::wl_registry *>(QtWayland::wl_registry::object());
         q->bind(registry, id, ver);
+        active = true;
+        emit q->activeChanged();
     }
 }
 
@@ -90,6 +105,12 @@ void QWaylandClientExtension::setVersion(const int ver)
     }
 }
 
+bool QWaylandClientExtension::active() const
+{
+    Q_D(const QWaylandClientExtension);
+    return d->active;
+}
+
 }
 
 QT_END_NAMESPACE

src/plugins/platforms/wayland/global/qwaylandclientextension.h

@@ -54,11 +54,13 @@ class Q_WAYLAND_CLIENT_EXPORT QWaylandClientExtension : public QObject
     Q_OBJECT
     Q_DECLARE_PRIVATE(QWaylandClientExtension)
     Q_PROPERTY(int protocolVersion READ version NOTIFY versionChanged)
+    Q_PROPERTY(bool active READ active NOTIFY activeChanged)
 public:
     QWaylandClientExtension(const int version);
 
     QWaylandIntegration *integration() const;
     int version() const;
+    bool active() const;
 
     virtual const struct wl_interface *extensionInterface() const = 0;
     virtual void bind(struct ::wl_registry *registry, int id, int version) = 0;
@@ -66,6 +68,7 @@ protected:
     void setVersion(const int version);
 Q_SIGNALS:
     void versionChanged();
+    void activeChanged();
 };
 
 template <typename T>

src/plugins/platforms/wayland/global/qwaylandclientextension_p.h

@@ -65,6 +65,7 @@ public:
 
     QWaylandIntegration *waylandIntegration;
     int version;
+    bool active;
 
 protected:
     void registry_global(uint32_t id, const QString &interfaceName, uint32_t version) Q_DECL_OVERRIDE;