Simplify client-side API for Wayland extensions

This simplifies the client-side API for Wayland extensions by
introducing QWaylandClientExtension/QWaylandClientExtensionTemplate
classes. These classes takes care of the initialization of the extension
if it matches the interface name.

Change-Id: I7c4fb34563563af4be072cdebda54954b79cddbe
Reviewed-by: Johan Helsing <johan.helsing@theqtcompany.com>
Reviewed-by: Giulio Camuffo <giulio.camuffo@kdab.com>

9 files changed, 310 insertions, 27 deletions

diff --git a/examples/wayland/custom-extension/client/customextension.cpp b/examples/wayland/custom-extension/client/customextension.cpp
index 81694fdab..68a1d4b81 100644
--- a/examples/wayland/custom-extension/client/customextension.cpp
+++ b/examples/wayland/custom-extension/client/customextension.cpp
@@ -48,14 +48,9 @@ QT_BEGIN_NAMESPACE
 
 namespace QtWaylandClient {
 
-CustomExtension::CustomExtension(QWaylandIntegration *wayland_integration)
-    : m_display(0)
+CustomExtension::CustomExtension()
+    : QWaylandClientExtensionTemplate(/* Supported protocol version */ 1 )
 {
-    // TODO: add a simpler API for this
-
-    QtWaylandClient::QWaylandDisplay *wayland_display = wayland_integration->display();
-    struct ::wl_registry *registry = wl_display_get_registry(wayland_display->wl_display());
-    QtWayland::wl_registry::init(registry);
 }
 
 void CustomExtension::sendRequest(const QString &text, int value)
@@ -73,13 +68,6 @@ void CustomExtension::example_extension_qtevent(struct wl_surface *surface,
     emit eventReceived(text, value);
 }
 
-void CustomExtension::registry_global(uint32_t id, const QString &interface, uint32_t version)
-{
-    if (interface == QStringLiteral("qt_example_extension")) {
-        QtWayland::qt_example_extension::init(QtWayland::wl_registry::object(), id, version);
-    }
-}
-
 }
 
 QT_END_NAMESPACE
diff --git a/examples/wayland/custom-extension/client/customextension.h b/examples/wayland/custom-extension/client/customextension.h
index d8797a9eb..16ace4bfd 100644
--- a/examples/wayland/custom-extension/client/customextension.h
+++ b/examples/wayland/custom-extension/client/customextension.h
@@ -43,20 +43,18 @@
 
 #include <qpa/qwindowsysteminterface.h>
 #include <QtWaylandClient/private/qwayland-wayland.h>
+#include <QtWaylandClient/qwaylandclientextension.h>
 #include "qwayland-custom.h"
 
 QT_BEGIN_NAMESPACE
 
 namespace QtWaylandClient {
 
-class QWaylandDisplay;
-class QWaylandIntegration;
-
-class CustomExtension : public QObject, QtWayland::qt_example_extension, public QtWayland::wl_registry
+class CustomExtension : public QWaylandClientExtensionTemplate<CustomExtension>, public QtWayland::qt_example_extension
 {
     Q_OBJECT
 public:
-    CustomExtension(QWaylandIntegration *wayland_integration);
+    CustomExtension();
 
 public slots:
     void sendRequest(const QString &text, int value);
@@ -65,15 +63,11 @@ signals:
     void eventReceived(const QString &text, uint value);
 
 private:
-    QWaylandDisplay *m_display;
-
     void example_extension_qtevent(struct wl_surface *surface,
                                    uint32_t time,
                                    const QString &text,
                                    uint32_t value) Q_DECL_OVERRIDE;
 
-    void registry_global(uint32_t id, const QString &interface, uint32_t version) Q_DECL_OVERRIDE;
-
 };
 
 }
diff --git a/examples/wayland/custom-extension/client/main.cpp b/examples/wayland/custom-extension/client/main.cpp
index 907053886..fe8ec59a8 100644
--- a/examples/wayland/custom-extension/client/main.cpp
+++ b/examples/wayland/custom-extension/client/main.cpp
@@ -66,9 +66,7 @@ public:
 
     qDebug() << "************* The Qt Custom Extension Example Plugin is active ************";
 
-    QWaylandIntegration *integration = new QWaylandIntegration();
-
-    extension_global = new CustomExtension(integration);
+    extension_global = new CustomExtension();
 
     // We need a way for client apps to get hold of the extension. The proper API for this is
     // QPlatformNativeInterface, but that's a low-level API using void*. There will be a nice
@@ -77,7 +75,7 @@ public:
     extension_global->setParent(qApp);
     extension_global->setObjectName("qt_example_custom_extension");
 
-    return integration;
+    return extension_global->integration();
 }
 
 }
diff --git a/src/client/client.pro b/src/client/client.pro
index edaff771a..1219ee345 100644
--- a/src/client/client.pro
+++ b/src/client/client.pro
@@ -111,6 +111,7 @@ HEADERS +=  qwaylandintegration_p.h \
 include(hardwareintegration/hardwareintegration.pri)
 include(shellintegration/shellintegration.pri)
 include(inputdeviceintegration/inputdeviceintegration.pri)
+include(global/global.pri)
 
 CONFIG += generated_privates
 MODULE_PLUGIN_TYPES = \
diff --git a/src/client/global/global.pri b/src/client/global/global.pri
new file mode 100644
index 000000000..53c76cbc9
--- /dev/null
+++ b/src/client/global/global.pri
@@ -0,0 +1,9 @@
+INCLUDEPATH += $$PWD
+
+HEADERS += \
+    $$PWD/qwaylandclientextension.h \
+    $$PWD/qwaylandclientextension_p.h
+
+SOURCES += \
+    $$PWD/qwaylandclientextension.cpp
+
diff --git a/src/client/global/qwaylandclientextension.cpp b/src/client/global/qwaylandclientextension.cpp
new file mode 100644
index 000000000..501f266f5
--- /dev/null
+++ b/src/client/global/qwaylandclientextension.cpp
@@ -0,0 +1,95 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 Erik Larsson.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the QtWaylandCompositor module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qwaylandclientextension.h"
+#include "qwaylandclientextension_p.h"
+#include <QtWaylandClient/private/qwaylanddisplay_p.h>
+#include <QtWaylandClient/private/qwaylandintegration_p.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace QtWaylandClient {
+
+QWaylandClientExtensionPrivate::QWaylandClientExtensionPrivate()
+    : QObjectPrivate()
+    , waylandIntegration(new QWaylandIntegration())
+    , version(-1)
+{
+    QtWaylandClient::QWaylandDisplay *waylandDisplay = waylandIntegration->display();
+    struct ::wl_registry *registry = wl_display_get_registry(waylandDisplay->wl_display());
+    QtWayland::wl_registry::init(registry);
+}
+
+void QWaylandClientExtensionPrivate::registry_global(uint32_t id, const QString &interfaceName, uint32_t ver)
+{
+    Q_Q(QWaylandClientExtension);
+    if (interfaceName == QLatin1String(q->extensionInterface()->name)) {
+        struct ::wl_registry *registry = static_cast<struct ::wl_registry *>(QtWayland::wl_registry::object());
+        q->bind(registry, id, ver);
+    }
+}
+
+QWaylandClientExtension::QWaylandClientExtension(const int ver)
+    : QObject(*new QWaylandClientExtensionPrivate())
+{
+    Q_D(QWaylandClientExtension);
+    d->version = ver;
+}
+
+QWaylandIntegration *QWaylandClientExtension::integration() const
+{
+    Q_D(const QWaylandClientExtension);
+    return d->waylandIntegration;
+}
+
+int QWaylandClientExtension::version() const
+{
+    Q_D(const QWaylandClientExtension);
+    return d->version;
+}
+
+void QWaylandClientExtension::setVersion(const int ver)
+{
+    Q_D(QWaylandClientExtension);
+    if (d->version != ver) {
+        d->version = ver;
+        emit versionChanged();
+    }
+}
+
+}
+
+QT_END_NAMESPACE
diff --git a/src/client/global/qwaylandclientextension.h b/src/client/global/qwaylandclientextension.h
new file mode 100644
index 000000000..efdfa46fb
--- /dev/null
+++ b/src/client/global/qwaylandclientextension.h
@@ -0,0 +1,105 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 Erik Larsson.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the QtWaylandCompositor module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QWAYLANDCLIENTEXTENSION_H
+#define QWAYLANDCLIENTEXTENSION_H
+
+#include <QObject>
+#include <qpa/qwindowsysteminterface.h>
+#include <QtWaylandClient/private/qwaylandclientexport_p.h>
+#include <QtWaylandClient/private/qwayland-wayland.h>
+QT_BEGIN_NAMESPACE
+
+namespace QtWaylandClient {
+
+class QWaylandIntegration;
+class QWaylandClientExtensionPrivate;
+class QWaylandClientExtensionTemplatePrivate;
+
+class Q_WAYLAND_CLIENT_EXPORT QWaylandClientExtension : public QObject
+{
+    Q_OBJECT
+    Q_DECLARE_PRIVATE(QWaylandClientExtension)
+    Q_PROPERTY(int protocolVersion READ version NOTIFY versionChanged)
+public:
+    QWaylandClientExtension(const int version);
+
+    QWaylandIntegration *integration() const;
+    int version() const;
+
+    virtual const struct wl_interface *extensionInterface() const = 0;
+    virtual void bind(struct ::wl_registry *registry, int id, int version) = 0;
+protected:
+    void setVersion(const int version);
+Q_SIGNALS:
+    void versionChanged();
+};
+
+template <typename T>
+class Q_WAYLAND_CLIENT_EXPORT QWaylandClientExtensionTemplate : public QWaylandClientExtension
+{
+    Q_DECLARE_PRIVATE(QWaylandClientExtensionTemplate)
+public:
+    QWaylandClientExtensionTemplate(const int ver) :
+        QWaylandClientExtension(ver)
+    {
+    }
+
+    const struct wl_interface *extensionInterface() const Q_DECL_OVERRIDE
+    {
+        return T::interface();
+    }
+
+    void bind(struct ::wl_registry *registry, int id, int ver)
+    {
+        T* instance = static_cast<T *>(this);
+        // Make sure lowest version is used of the supplied version from the
+        // developer and the version specified in the protocol and also the
+        // compositor version.
+        if (this->version() > T::interface()->version) {
+            qWarning("Supplied protocol version to QWaylandClientExtensionTemplate is higher than the version of the protocol, using protocol version instead.");
+        }
+        int minVersion = qMin(ver, qMin(T::interface()->version, this->version()));
+        setVersion(minVersion);
+        instance->init(registry, id, minVersion);
+    }
+};
+
+}
+
+QT_END_NAMESPACE
+
+#endif // QWAYLANDCLIENTEXTENSION_H
diff --git a/src/client/global/qwaylandclientextension_p.h b/src/client/global/qwaylandclientextension_p.h
new file mode 100644
index 000000000..2676f0ee6
--- /dev/null
+++ b/src/client/global/qwaylandclientextension_p.h
@@ -0,0 +1,85 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 Erik Larsson.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the QtWaylandCompositor module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QWAYLANDCLIENTEXTENSION_P_H
+#define QWAYLANDCLIENTEXTENSION_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include "qwaylandclientextension.h"
+#include <QtCore/private/qobject_p.h>
+#include <QtWaylandClient/private/qwaylandintegration_p.h>
+#include <QtWaylandClient/private/qwayland-wayland.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace QtWaylandClient {
+
+class Q_WAYLAND_CLIENT_EXPORT QWaylandClientExtensionPrivate : public QObjectPrivate, public QtWayland::wl_registry
+{
+    Q_DECLARE_PUBLIC(QWaylandClientExtension)
+public:
+    QWaylandClientExtensionPrivate();
+
+    QWaylandIntegration *waylandIntegration;
+    int version;
+
+protected:
+    void registry_global(uint32_t id, const QString &interfaceName, uint32_t version) Q_DECL_OVERRIDE;
+};
+
+class Q_WAYLAND_CLIENT_EXPORT QWaylandClientExtensionTemplatePrivate : public QWaylandClientExtensionPrivate
+{
+public:
+    QWaylandClientExtensionTemplatePrivate()
+        : QWaylandClientExtensionPrivate()
+    { }
+};
+
+}
+
+QT_END_NAMESPACE
+
+#endif  /*QWAYLANDCLIENTEXTENSION_P_H*/
diff --git a/src/qtwaylandscanner/qtwaylandscanner.cpp b/src/qtwaylandscanner/qtwaylandscanner.cpp
index afe3b80ec..b609523b6 100644
--- a/src/qtwaylandscanner/qtwaylandscanner.cpp
+++ b/src/qtwaylandscanner/qtwaylandscanner.cpp
@@ -878,6 +878,8 @@ void process(QXmlStreamReader &xml, const QByteArray &headerPath, const QByteArr
             printf("        const struct ::%s *object() const { return m_%s; }\n", interfaceName, interfaceName);
             printf("\n");
             printf("        bool isInitialized() const;\n");
+            printf("\n");
+            printf("        static const struct ::wl_interface *interface();\n");
 
             printEnums(interface.enums);
 
@@ -1003,6 +1005,12 @@ void process(QXmlStreamReader &xml, const QByteArray &headerPath, const QByteArr
             printf("    {\n");
             printf("        return m_%s != 0;\n", interfaceName);
             printf("    }\n");
+            printf("\n");
+
+            printf("    const struct wl_interface *%s::interface()\n", interfaceName);
+            printf("    {\n");
+            printf("        return &::%s_interface;\n", interfaceName);
+            printf("    }\n");
 
             for (int i = 0; i < interface.requests.size(); ++i) {
                 printf("\n");