qobjectregistrysingleton_p.h

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// Copyright (C) 2026 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
 
//
//  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.
//
 
#ifndef QOBJECTREGISTRYSINGLETON_P_H
#define QOBJECTREGISTRYSINGLETON_P_H
 
#include <QtQmlDesignSupport/qtqmldesignsupportexports.h>
 
#include <QtCore/qhash.h>
#include <QtCore/qobject.h>
#include <QtCore/qset.h>
#include <QtCore/qstring.h>
#include <QtQml/qqml.h>
#include <QtQml/private/qqmlguard_p.h>
 
#include <memory>
 
QT_BEGIN_NAMESPACE
 
class QAbstractObjectRegistryRefPrivate;
class QQmlEngine;
 
class Q_QMLDESIGNSUPPORT_EXPORT QObjectRegistrySingleton : public QObject
{
    Q_OBJECT
    QML_SINGLETON
    QML_NAMED_ELEMENT(InternalObjectRegistry)
 
public:
    explicit QObjectRegistrySingleton(QObject *parent = nullptr);
    ~QObjectRegistrySingleton();
 
    void registerRef(QAbstractObjectRegistryRefPrivate *ref);
    void deregisterRef(QAbstractObjectRegistryRefPrivate *ref);
 
    void add(const QString &key, QObject *obj);
    void remove(const QString &key, QObject *obj);
    QSet<QObject*> objects(const QString &key) const;
 
    static QObjectRegistrySingleton *registryForObject(QObject *obj);
    static QObjectRegistrySingleton *registryForEngine(QQmlEngine *engine);
 
private:
    enum class Notification { ObjectAdded, ObjectRemoved };
 
    void notifyRefs(const QString &key, QObject *obj, Notification notification);
 
    class ObjectGuard : public QQmlGuard<QObject>
    {
    public:
        ObjectGuard(QObjectRegistrySingleton *owner, const QString &key, QObject *obj)
            : QQmlGuard<QObject>(&ObjectGuard::objectDestroyedImpl, obj)
            , m_owner(owner)
            , m_key(key)
            , m_object(obj)
        {
        }
 
    private:
        static void objectDestroyedImpl(QQmlGuardImpl *guard)
        {
            ObjectGuard *self = static_cast<ObjectGuard *>(guard);
            QObjectRegistrySingleton *owner = self->m_owner;
            const QString key = self->m_key;
            QObject *obj = self->m_object;
 
            owner->remove(key, obj);
        }
 
        QObjectRegistrySingleton *m_owner = nullptr;
        QString m_key;
        QObject *m_object = nullptr;
    };
 
    QHash<QString, QHash<QObject *, ObjectGuard *>> m_objects;
    QHash<QString, QSet<QAbstractObjectRegistryRefPrivate *>> m_refs;
};
 
QT_END_NAMESPACE
 
#endif // QOBJECTREGISTRYSINGLETON_P_H