Make the underlying transport mechanism of the webchannel pluggable.

This enables us to optionally use navigator.qt instead of a WebSocket,
which is nicer setup-wise and is also slightly faster:

navigator.qt:
284.0 msecs per iteration (total: 2,840, iterations: 10)
WebSocket:
295.8 msecs per iteration (total: 2,959, iterations: 10)

The baseline is ca. 203 msecs, which would mean a performance boost
of ca. 12.7%.

Furthermore, this sets the fundation to eventually add a WebEngine
transport mechanism. The WebViewTransport should also be removed and
instead the WebView itself should directly implement the
WebChannelTransportInterface.

Change-Id: I368bb27e38ffa2f17ffeb7f5ae695690f6f5ad21
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

6 files changed, 276 insertions, 6 deletions

diff --git a/src/imports/webchannel/plugin.cpp b/src/imports/webchannel/plugin.cpp
index 92aac79..589e3cb 100644
--- a/src/imports/webchannel/plugin.cpp
+++ b/src/imports/webchannel/plugin.cpp
@@ -43,6 +43,11 @@
 #include <QtQml/QQmlExtensionPlugin>
 
 #include "qmlwebchannel.h"
+#include "qwebsockettransport.h"
+#include "qmlwebviewtransport.h"
+#include "qwebchanneltransportinterface.h"
+
+QML_DECLARE_INTERFACE_HASMETATYPE(QWebChannelTransportInterface);
 
 QT_BEGIN_NAMESPACE
 
@@ -57,10 +62,13 @@ public:
 
 void QWebChannelPlugin::registerTypes(const char *uri)
 {
+    qmlRegisterInterface<QWebChannelTransportInterface>("QWebChannelTransportInterface");
+
     int major = 1;
     int minor = 0;
     qmlRegisterType<QmlWebChannel>(uri, major, minor, "WebChannel");
-
+    qmlRegisterType<QWebSocketTransport>(uri, major, minor, "WebSocketTransport");
+    qmlRegisterType<QmlWebViewTransport>(uri, major, minor, "WebViewTransport");
 }
 
 QT_END_NAMESPACE
diff --git a/src/imports/webchannel/qmlwebchannel.cpp b/src/imports/webchannel/qmlwebchannel.cpp
index 7c70f5c..dc7398d 100644
--- a/src/imports/webchannel/qmlwebchannel.cpp
+++ b/src/imports/webchannel/qmlwebchannel.cpp
@@ -51,7 +51,6 @@ QT_USE_NAMESPACE
 QmlWebChannel::QmlWebChannel(QObject *parent)
     : QWebChannel(parent)
 {
-
 }
 
 QmlWebChannel::~QmlWebChannel()
@@ -99,6 +98,37 @@ QmlWebChannelAttached *QmlWebChannel::qmlAttachedProperties(QObject *obj)
     return new QmlWebChannelAttached(obj);
 }
 
+void QmlWebChannel::connectTo(QObject *transport)
+{
+    if (QWebChannelTransportInterface *iface = qobject_cast<QWebChannelTransportInterface*>(transport)) {
+        m_connectedObjects.insert(transport, iface);
+        QWebChannel::connectTo(iface);
+        connect(transport, SIGNAL(destroyed(QObject*)), SLOT(transportDestroyed(QObject*)), Qt::UniqueConnection);
+    } else {
+        qWarning() << "Cannot connect to transport" << transport << " - it does not implement the QWebChannelTransportInterface.";
+    }
+}
+
+void QmlWebChannel::disconnectFrom(QObject *transport)
+{
+    if (QWebChannelTransportInterface *iface = qobject_cast<QWebChannelTransportInterface*>(transport)) {
+        QWebChannel::disconnectFrom(iface);
+        disconnect(transport, SIGNAL(destroyed(QObject*)), this, SLOT(transportDestroyed(QObject*)));
+        m_connectedObjects.remove(transport);
+    } else {
+        qWarning() << "Cannot disconnect from transport" << transport << " - it does not implement the QWebChannelTransportInterface.";
+    }
+}
+
+void QmlWebChannel::transportDestroyed(QObject *transport)
+{
+    QWebChannelTransportInterface *iface = m_connectedObjects.take(transport);
+    const int idx = d->transports.indexOf(iface);
+    if (idx != -1) {
+        d->transports.remove(idx);
+    }
+}
+
 QQmlListProperty<QObject> QmlWebChannel::registeredObjects()
 {
     return QQmlListProperty<QObject>(this, 0,
@@ -144,3 +174,37 @@ void QmlWebChannel::registeredObjects_clear(QQmlListProperty<QObject> *prop)
     }
     return channel->m_registeredObjects.clear();
 }
+
+QQmlListProperty<QWebChannelTransportInterface> QmlWebChannel::transports()
+{
+    return QQmlListProperty<QWebChannelTransportInterface>(this, 0,
+                                                           transports_append,
+                                                           transports_count,
+                                                           transports_at,
+                                                           transports_clear);
+}
+
+void QmlWebChannel::transports_append(QQmlListProperty<QWebChannelTransportInterface> *prop, QWebChannelTransportInterface *transport)
+{
+    QWebChannel *channel = static_cast<QWebChannel*>(prop->object);
+    channel->connectTo(transport);
+}
+
+int QmlWebChannel::transports_count(QQmlListProperty<QWebChannelTransportInterface> *prop)
+{
+    return static_cast<QmlWebChannel*>(prop->object)->d->transports.size();
+}
+
+QWebChannelTransportInterface *QmlWebChannel::transports_at(QQmlListProperty<QWebChannelTransportInterface> *prop, int index)
+{
+    return static_cast<QmlWebChannel*>(prop->object)->d->transports.at(index);
+}
+
+void QmlWebChannel::transports_clear(QQmlListProperty<QWebChannelTransportInterface> *prop)
+{
+    QWebChannel *channel = static_cast<QWebChannel*>(prop->object);
+    foreach (QWebChannelTransportInterface *transport, channel->d->transports) {
+        channel->disconnectFrom(transport);
+    }
+    Q_ASSERT(channel->d->transports.isEmpty());
+}
diff --git a/src/imports/webchannel/qmlwebchannel.h b/src/imports/webchannel/qmlwebchannel.h
index bcbb9cf..c45796f 100644
--- a/src/imports/webchannel/qmlwebchannel.h
+++ b/src/imports/webchannel/qmlwebchannel.h
@@ -45,6 +45,7 @@
 #include <qwebchannel.h>
 
 #include "qmlwebchannelattached.h"
+#include "qwebchanneltransportinterface.h"
 
 #include <QVector>
 
@@ -53,13 +54,13 @@
 
 QT_BEGIN_NAMESPACE
 
-class QmlWebChannelAttached;
-
 class QmlWebChannel : public QWebChannel
 {
     Q_OBJECT
 
+    Q_PROPERTY( QQmlListProperty<QWebChannelTransportInterface> connections READ transports );
     Q_PROPERTY( QQmlListProperty<QObject> registeredObjects READ registeredObjects )
+
 public:
     QmlWebChannel(QObject *parent = 0);
     virtual ~QmlWebChannel();
@@ -67,13 +68,19 @@ public:
     Q_INVOKABLE void registerObjects(const QVariantMap& objects);
     QQmlListProperty<QObject> registeredObjects();
 
+    QQmlListProperty<QWebChannelTransportInterface> transports();
+
     // TODO: remove this by replacing QML with C++ tests
     Q_INVOKABLE bool test_clientIsIdle() const;
 
     static QmlWebChannelAttached* qmlAttachedProperties(QObject *obj);
 
+    Q_INVOKABLE void connectTo(QObject *transport);
+    Q_INVOKABLE void disconnectFrom(QObject *transport);
+
 private slots:
     void objectIdChanged(const QString &newId);
+    void transportDestroyed(QObject *transport);
 
 private:
     static void registeredObjects_append(QQmlListProperty<QObject> *prop, QObject* item);
@@ -81,7 +88,14 @@ private:
     static QObject *registeredObjects_at(QQmlListProperty<QObject> *prop, int index);
     static void registeredObjects_clear(QQmlListProperty<QObject> *prop);
 
+    static void transports_append(QQmlListProperty<QWebChannelTransportInterface> *prop, QWebChannelTransportInterface* item);
+    static int transports_count(QQmlListProperty<QWebChannelTransportInterface> *prop);
+    static QWebChannelTransportInterface *transports_at(QQmlListProperty<QWebChannelTransportInterface> *prop, int index);
+    static void transports_clear(QQmlListProperty<QWebChannelTransportInterface> *prop);
+
     QVector<QObject*> m_registeredObjects;
+    // required as when the object is destroyed, we must still find the address of the base class somehow
+    QHash<QObject*, QWebChannelTransportInterface*> m_connectedObjects;
 };
 
 QML_DECLARE_TYPE( QmlWebChannel )
diff --git a/src/imports/webchannel/qmlwebviewtransport.cpp b/src/imports/webchannel/qmlwebviewtransport.cpp
new file mode 100644
index 0000000..7fb9d16
--- /dev/null
+++ b/src/imports/webchannel/qmlwebviewtransport.cpp
@@ -0,0 +1,103 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Milian Wolff <milian.wolff@kdab.com>
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtWebChannel module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/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 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 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 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qmlwebviewtransport.h"
+
+#include <QVariantMap>
+
+QT_USE_NAMESPACE
+
+QmlWebViewTransport::QmlWebViewTransport(QObject *parent)
+    : QObject(parent)
+    , m_webViewExperimental(Q_NULLPTR)
+    , m_handler(Q_NULLPTR)
+{
+}
+
+QmlWebViewTransport::~QmlWebViewTransport()
+{
+
+}
+
+void QmlWebViewTransport::setWebViewExperimental(QObject *webViewExperimental)
+{
+    if (webViewExperimental != m_webViewExperimental) {
+        if (m_webViewExperimental) {
+            disconnect(m_webViewExperimental, 0, this, 0);
+        }
+        m_webViewExperimental = webViewExperimental;
+        connect(m_webViewExperimental, SIGNAL(messageReceived(QVariantMap)), this, SLOT(handleWebViewMessage(QVariantMap)));
+        emit webViewChanged(webViewExperimental);
+    }
+}
+
+QObject *QmlWebViewTransport::webViewExperimental() const
+{
+    return m_webViewExperimental;
+}
+
+void QmlWebViewTransport::sendMessage(const QString &message) const
+{
+    if (!m_webViewExperimental) {
+        qWarning("Cannot send message - did you forget to set the webViewExperimental property?");
+        return;
+    }
+    QMetaObject::invokeMethod(m_webViewExperimental, "postMessage", Q_ARG(QString, message));
+}
+
+void QmlWebViewTransport::sendMessage(const QByteArray &message) const
+{
+    sendMessage(QString::fromUtf8(message));
+}
+
+void QmlWebViewTransport::handleWebViewMessage(const QVariantMap &message)
+{
+    if (m_handler) {
+        const QString &data = message[QStringLiteral("data")].toString();
+        m_handler->handleMessage(data);
+        emit messageReceived(data);
+    }
+}
+
+void QmlWebViewTransport::setMessageHandler(QWebChannelMessageHandlerInterface *handler)
+{
+    m_handler = handler;
+}
diff --git a/src/imports/webchannel/qmlwebviewtransport.h b/src/imports/webchannel/qmlwebviewtransport.h
new file mode 100644
index 0000000..98dc504
--- /dev/null
+++ b/src/imports/webchannel/qmlwebviewtransport.h
@@ -0,0 +1,79 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Milian Wolff <milian.wolff@kdab.com>
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtWebChannel module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/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 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 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 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QMLWEBVIEWTRANSPORT_H
+#define QMLWEBVIEWTRANSPORT_H
+
+#include <qwebchanneltransportinterface.h>
+
+QT_BEGIN_NAMESPACE
+
+class QmlWebViewTransport : public QObject, public QWebChannelTransportInterface
+{
+    Q_OBJECT
+    Q_INTERFACES(QWebChannelTransportInterface)
+    Q_PROPERTY(QObject *webViewExperimental READ webViewExperimental WRITE setWebViewExperimental NOTIFY webViewChanged)
+public:
+    explicit QmlWebViewTransport(QObject *parent = 0);
+    ~QmlWebViewTransport() Q_DECL_OVERRIDE;
+
+    void sendMessage(const QString &message) const Q_DECL_OVERRIDE;
+    void sendMessage(const QByteArray &message) const Q_DECL_OVERRIDE;
+    void setMessageHandler(QWebChannelMessageHandlerInterface *handler) Q_DECL_OVERRIDE;
+
+    void setWebViewExperimental(QObject *webViewExperimental);
+    QObject *webViewExperimental() const;
+
+signals:
+    void webViewChanged(QObject *webViewExperimental);
+    void messageReceived(const QString &message);
+
+private slots:
+    void handleWebViewMessage(const QVariantMap &message);
+
+private:
+    QObject *m_webViewExperimental;
+    QWebChannelMessageHandlerInterface *m_handler;
+};
+
+QT_END_NAMESPACE
+
+#endif // QMLWEBVIEWTRANSPORT_H
diff --git a/src/imports/webchannel/webchannel.pro b/src/imports/webchannel/webchannel.pro
index c1959f5..3042854 100644
--- a/src/imports/webchannel/webchannel.pro
+++ b/src/imports/webchannel/webchannel.pro
@@ -6,10 +6,12 @@ VPATH += ../../webchannel
 SOURCES += \
     plugin.cpp \
     qmlwebchannel.cpp \
-    qmlwebchannelattached.cpp
+    qmlwebchannelattached.cpp \
+    qmlwebviewtransport.cpp
 
 HEADERS += \
     qmlwebchannel.h \
-    qmlwebchannelattached.h
+    qmlwebchannelattached.h \
+    qmlwebviewtransport.h
 
 load(qml_plugin)