qqmlproxymetaobject.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
// Qt-Security score:significant
 
#include "qqmlproxymetaobject_p.h"
#include "qqmlproperty_p.h"
 
QT_BEGIN_NAMESPACE
 
QQmlProxyMetaObject::QQmlProxyMetaObject(QObject *obj, const QList<ProxyData> *mList)
    : metaObjects(mList), proxies(nullptr), parent(nullptr), object(obj)
{
    metaObject = metaObjects->constFirst().metaObject;
 
    QObjectPrivate *op = QObjectPrivate::get(obj);
    if (op->metaObject)
        parent = op->metaObject;
 
    op->metaObject = this;
}
 
QQmlProxyMetaObject::~QQmlProxyMetaObject()
{
    // If the parent still exists, we're being deleted while the object is still alive.
    // In that case, restore the parent.
    if (QDynamicMetaObjectData *dynamicParent = std::exchange(parent, nullptr))
        QObjectPrivate::get(object)->metaObject = dynamicParent;
 
    if (proxies)
        delete [] proxies;
    proxies = nullptr;
}
 
QObject *QQmlProxyMetaObject::getProxy(int index)
{
    if (!proxies) {
        proxies = new QObject *[metaObjects->size()];
        ::memset(proxies, 0, sizeof(QObject *) * metaObjects->size());
    }
 
    if (!proxies[index]) {
        const ProxyData &data = metaObjects->at(index);
        if (!data.createFunc)
            return nullptr;
 
        QObject *proxy = data.createFunc(object);
        const QMetaObject *metaObject = proxy->metaObject();
        proxies[index] = proxy;
 
        int localOffset = data.metaObject->methodOffset();
        int methodOffset = metaObject->methodOffset();
        int methods = metaObject->methodCount() - methodOffset;
 
        // ### - Can this be done more optimally?
        for (int jj = 0; jj < methods; ++jj) {
            QMetaMethod method =
                metaObject->method(jj + methodOffset);
            if (method.methodType() == QMetaMethod::Signal)
                QQmlPropertyPrivate::connect(proxy, methodOffset + jj, object, localOffset + jj);
        }
    }
 
    return proxies[index];
}
 
int QQmlProxyMetaObject::metaCall(QObject *o, QMetaObject::Call c, int id, void **a)
{
    Q_ASSERT(object == o);
 
    switch (c) {
    case QMetaObject::ReadProperty:
    case QMetaObject::WriteProperty: {
        if (id < metaObjects->constLast().propertyOffset)
            break;
 
        for (int ii = 0; ii < metaObjects->size(); ++ii) {
            const int globalPropertyOffset = metaObjects->at(ii).propertyOffset;
            if (id < globalPropertyOffset)
                continue;
 
            QObject *proxy = getProxy(ii);
            Q_ASSERT(proxy);
            const int localProxyOffset = proxy->metaObject()->propertyOffset();
            const int localProxyId = id - globalPropertyOffset + localProxyOffset;
            return proxy->qt_metacall(c, localProxyId, a);
        }
        break;
    }
    case QMetaObject::InvokeMetaMethod: {
        if (id < metaObjects->constLast().methodOffset)
            break;
 
        QMetaMethod m = object->metaObject()->method(id);
        if (m.methodType() == QMetaMethod::Signal) {
            QMetaObject::activate(object, id, a);
            return -1;
        }
 
        for (int ii = 0; ii < metaObjects->size(); ++ii) {
            const int globalMethodOffset = metaObjects->at(ii).methodOffset;
            if (id < globalMethodOffset)
                continue;
 
            QObject *proxy = getProxy(ii);
            Q_ASSERT(proxy);
            const int localMethodOffset = proxy->metaObject()->methodOffset();
            const int localMethodId = id - globalMethodOffset + localMethodOffset;
            return proxy->qt_metacall(c, localMethodId, a);
        }
 
        break;
    }
    case QMetaObject::CustomCall: {
        if ((id & ~MaxExtensionCount) != ExtensionObjectId)
            break;
        int index = id & MaxExtensionCount;
        if (qsizetype(index) >= metaObjects->size())
            break;
        a[0] = getProxy(index);
        return id;
    }
    default:
        break;
    }
 
    if (parent)
        return parent->metaCall(o, c, id, a);
    else
        return object->qt_metacall(c, id, a);
}
 
void QQmlProxyMetaObject::objectDestroyed(QObject *object)
{
    // The object is being deleted. parent will likely delete itself on objectDestroyed().
    // We don't want to keep a dangling pointer, so null it. Also, we're in
    // ~QObjectPrivate(). Don't mess with object anymore here.
    if (QDynamicMetaObjectData *dynamicParent = std::exchange(parent, nullptr))
        dynamicParent->objectDestroyed(object);
    QDynamicMetaObjectData::objectDestroyed(object);
}
 
QT_END_NAMESPACE