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/****************************************************************************
**
** 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.
**
** $QT_BEGIN_LICENSE:LGPL3$
** 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 SIGNALHANDLER_H
#define SIGNALHANDLER_H
//
// W A R N I N G
// -------------
//
// This file is not part of the Qt API. It exists for the convenience
// of other Qt classes. This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
#include <QObject>
#include <QHash>
#include <QVector>
#include <QMetaMethod>
#include <QDebug>
QT_BEGIN_NAMESPACE
namespace Qt3DCore {
/**
* The property change handler is similar to QSignalSpy, but geared towards the usecase of Qt3D.
*
* It allows connecting to any number of property change signals of the receiver object and forwards
* the signal invocations to the Receiver by calling its propertyChanged function.
*/
template<class Receiver>
class PropertyChangeHandler : public QObject
{
public:
PropertyChangeHandler(Receiver *receiver, QObject *parent = Q_NULLPTR);
/**
* Connect to the change signal of @p property in @p object.
*/
void connectToPropertyChange(const QObject *object, int propertyIndex);
/**
* Disconnect from the change signal of @p property in @p object.
*/
void disconnectFromPropertyChange(const QObject *object, int propertyIndex);
/**
* @internal
*
* Custom implementation of qt_metacall which calls propertyChanged() on the receiver for
* connected signals.
*/
int qt_metacall(QMetaObject::Call call, int methodId, void **args) Q_DECL_OVERRIDE;
private:
Receiver *m_receiver;
};
template<class Receiver>
PropertyChangeHandler<Receiver>::PropertyChangeHandler(Receiver *receiver, QObject *parent)
: QObject(parent)
, m_receiver(receiver)
{
}
template<class Receiver>
void PropertyChangeHandler<Receiver>::connectToPropertyChange(const QObject *object, int propertyIndex)
{
const QMetaObject *metaObject = object->metaObject();
const QMetaProperty property = metaObject->property(propertyIndex);
if (!property.hasNotifySignal())
return;
static const int memberOffset = QObject::staticMetaObject.methodCount();
QMetaObject::Connection connection = QMetaObject::connect(object, property.notifySignalIndex(),
this, memberOffset + propertyIndex,
Qt::DirectConnection, 0);
Q_ASSERT(connection);
Q_UNUSED(connection);
}
template<class Receiver>
void PropertyChangeHandler<Receiver>::disconnectFromPropertyChange(const QObject *object, int propertyIndex)
{
const QMetaObject *metaObject = object->metaObject();
const QMetaProperty property = metaObject->property(propertyIndex);
if (!property.hasNotifySignal())
return;
static const int memberOffset = QObject::staticMetaObject.methodCount();
QMetaObject::disconnect(object, property.notifySignalIndex(), this, memberOffset + propertyIndex);
}
template<class Receiver>
int PropertyChangeHandler<Receiver>::qt_metacall(QMetaObject::Call call, int methodId, void **args)
{
methodId = QObject::qt_metacall(call, methodId, args);
if (methodId < 0)
return methodId;
if (call == QMetaObject::InvokeMetaMethod) {
m_receiver->propertyChanged(methodId);
return -1;
}
return methodId;
}
}
QT_END_NAMESPACE
#endif // SIGNALHANDLER_H
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