Add declarative object-registration API to QML WebChannel.

The new registeredObjects list property is now preferred over the old
imparative registerObject/registerObjects API.

Items that are added to the list need an attached WebChannel.id property
which holds the identifier under which the object is published to remote
clients.

Change-Id: I96a8047b9a85e27f3fd48c900180c22ebd20eb35
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

5 files changed, 236 insertions, 4 deletions

diff --git a/src/imports/webchannel/qmlwebchannel.cpp b/src/imports/webchannel/qmlwebchannel.cpp
index a7a6db0..22da1ac 100644
--- a/src/imports/webchannel/qmlwebchannel.cpp
+++ b/src/imports/webchannel/qmlwebchannel.cpp
@@ -45,6 +45,8 @@
 #include "qwebchannel_p.h"
 #include "qmetaobjectpublisher_p.h"
 
+#include <QtQml/QQmlContext>
+
 QmlWebChannel::QmlWebChannel(QObject *parent)
     : QWebChannel(parent)
 {
@@ -73,3 +75,71 @@ bool QmlWebChannel::test_clientIsIdle() const
 {
     return d->publisher->clientIsIdle;
 }
+
+void QmlWebChannel::objectIdChanged(const QString &newId)
+{
+    const QmlWebChannelAttached *const attached = qobject_cast<QmlWebChannelAttached*>(sender());
+    Q_ASSERT(attached);
+    Q_ASSERT(attached->parent());
+    Q_ASSERT(m_registeredObjects.contains(attached->parent()));
+
+    QObject *const object = attached->parent();
+    const QString &oldId = d->publisher->registeredObjectIds.value(object);
+
+    if (!oldId.isEmpty()) {
+        deregisterObject(object);
+    }
+
+    registerObject(newId, object);
+}
+
+QmlWebChannelAttached *QmlWebChannel::qmlAttachedProperties(QObject *obj)
+{
+    return new QmlWebChannelAttached(obj);
+}
+
+QQmlListProperty<QObject> QmlWebChannel::registeredObjects()
+{
+    return QQmlListProperty<QObject>(this, 0,
+                                     registeredObjects_append,
+                                     registeredObjects_count,
+                                     registeredObjects_at,
+                                     registeredObjects_clear);
+}
+
+void QmlWebChannel::registeredObjects_append(QQmlListProperty<QObject> *prop, QObject *object)
+{
+    const QmlWebChannelAttached *const attached = qobject_cast<QmlWebChannelAttached*>(
+        qmlAttachedPropertiesObject<QmlWebChannel>(object, false /* don't create */));
+    if (!attached) {
+        const QQmlContext *const context = qmlContext(object);
+        qWarning() << "Cannot register object" << context->nameForObject(object) << '(' << object << ") without attached WebChannel.id property. Did you forget to set it?";
+        return;
+    }
+    QmlWebChannel *channel = static_cast<QmlWebChannel*>(prop->object);
+    if (!attached->id().isEmpty()) {
+        // TODO: warning in such cases?
+        channel->registerObject(attached->id(), object);
+    }
+    channel->m_registeredObjects.append(object);
+    connect(attached, SIGNAL(idChanged(QString)), channel, SLOT(objectIdChanged(QString)));
+}
+
+int QmlWebChannel::registeredObjects_count(QQmlListProperty<QObject> *prop)
+{
+    return static_cast<QmlWebChannel*>(prop->object)->m_registeredObjects.size();
+}
+
+QObject *QmlWebChannel::registeredObjects_at(QQmlListProperty<QObject> *prop, int index)
+{
+    return static_cast<QmlWebChannel*>(prop->object)->m_registeredObjects.at(index);
+}
+
+void QmlWebChannel::registeredObjects_clear(QQmlListProperty<QObject> *prop)
+{
+    QmlWebChannel *channel = static_cast<QmlWebChannel*>(prop->object);
+    foreach (QObject *object, channel->m_registeredObjects) {
+        channel->deregisterObject(object);
+    }
+    return channel->m_registeredObjects.clear();
+}
diff --git a/src/imports/webchannel/qmlwebchannel.h b/src/imports/webchannel/qmlwebchannel.h
index b52bc8b..9e25b45 100644
--- a/src/imports/webchannel/qmlwebchannel.h
+++ b/src/imports/webchannel/qmlwebchannel.h
@@ -45,19 +45,45 @@
 
 #include <qwebchannel.h>
 
+#include "qmlwebchannelattached.h"
+
+#include <QVector>
+
+#include <QtQml/qqml.h>
+#include <QtQml/QQmlListProperty>
+
+class QmlWebChannelAttached;
+
 class QmlWebChannel : public QWebChannel
 {
     Q_OBJECT
 
+    Q_PROPERTY( QQmlListProperty<QObject> registeredObjects READ registeredObjects )
 public:
     QmlWebChannel(QObject *parent = 0);
     virtual ~QmlWebChannel();
 
-    // TODO: replace by list property
-    Q_INVOKABLE void registerObjects(const QVariantMap &objects);
+    Q_INVOKABLE void registerObjects(const QVariantMap& objects);
+    QQmlListProperty<QObject> registeredObjects();
 
     // TODO: remove this by replacing QML with C++ tests
     Q_INVOKABLE bool test_clientIsIdle() const;
+
+    static QmlWebChannelAttached* qmlAttachedProperties(QObject *obj);
+
+private slots:
+    void objectIdChanged(const QString &newId);
+
+private:
+    static void registeredObjects_append(QQmlListProperty<QObject> *prop, QObject* item);
+    static int registeredObjects_count(QQmlListProperty<QObject> *prop);
+    static QObject *registeredObjects_at(QQmlListProperty<QObject> *prop, int index);
+    static void registeredObjects_clear(QQmlListProperty<QObject> *prop);
+
+    QVector<QObject*> m_registeredObjects;
 };
 
+QML_DECLARE_TYPE( QmlWebChannel )
+QML_DECLARE_TYPEINFO( QmlWebChannel, QML_HAS_ATTACHED_PROPERTIES )
+
 #endif // QMLWEBCHANNEL_H
diff --git a/src/imports/webchannel/qmlwebchannelattached.cpp b/src/imports/webchannel/qmlwebchannelattached.cpp
new file mode 100644
index 0000000..9a413fc
--- /dev/null
+++ b/src/imports/webchannel/qmlwebchannelattached.cpp
@@ -0,0 +1,67 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** 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 "qmlwebchannelattached.h"
+
+QmlWebChannelAttached::QmlWebChannelAttached(QObject *parent)
+    : QObject(parent)
+{
+
+}
+
+QmlWebChannelAttached::~QmlWebChannelAttached()
+{
+
+}
+
+QString QmlWebChannelAttached::id() const
+{
+    return m_id;
+}
+
+void QmlWebChannelAttached::setId(const QString &id)
+{
+    if (id != m_id) {
+        m_id = id;
+        emit idChanged(id);
+    }
+}
diff --git a/src/imports/webchannel/qmlwebchannelattached.h b/src/imports/webchannel/qmlwebchannelattached.h
new file mode 100644
index 0000000..c705c25
--- /dev/null
+++ b/src/imports/webchannel/qmlwebchannelattached.h
@@ -0,0 +1,67 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** 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 QMLWEBCHANNELATTACHED_H
+#define QMLWEBCHANNELATTACHED_H
+
+#include <QObject>
+
+class QmlWebChannelAttached : public QObject
+{
+    Q_OBJECT
+
+    Q_PROPERTY( QString id READ id WRITE setId NOTIFY idChanged FINAL )
+public:
+    explicit QmlWebChannelAttached(QObject *parent = 0);
+    virtual ~QmlWebChannelAttached();
+
+    QString id() const;
+    void setId(const QString &id);
+
+signals:
+    void idChanged(const QString &id);
+
+private:
+    QString m_id;
+};
+
+#endif // QMLWEBCHANNELATTACHED_H
diff --git a/src/imports/webchannel/webchannel.pro b/src/imports/webchannel/webchannel.pro
index 3051077..c1959f5 100644
--- a/src/imports/webchannel/webchannel.pro
+++ b/src/imports/webchannel/webchannel.pro
@@ -5,9 +5,11 @@ VPATH += ../../webchannel
 
 SOURCES += \
     plugin.cpp \
-    qmlwebchannel.cpp
+    qmlwebchannel.cpp \
+    qmlwebchannelattached.cpp
 
 HEADERS += \
-    qmlwebchannel.h
+    qmlwebchannel.h \
+    qmlwebchannelattached.h
 
 load(qml_plugin)