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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
++
++ #include "qobjectregistryref_p.h"
++
++ #include <private/qobjectregistrysingleton_p.h>
++
++ #include <QtQml/qqmlinfo.h>
++
++ QT_BEGIN_NAMESPACE
++
++ /*!
++ \class QObjectRegistryRef
++ \inmodule QtQmlDesignSupport
++ \ingroup qmldesignsupport
++ \brief This class is used to access an object registered with ObjectRegistry QML type from
++ C++ code.
++
++ Example usage:
++ \snippet doc_src_objectregistry.cpp 0
++ \codeline
++ \snippet doc_src_objectregistry.cpp 2
++
++ \sa ObjectRegistry, QAbstractObjectRegistryRef::key
++ */
++
++ /*!
++ \qmltype ObjectRegistryRef
++ \nativetype QObjectRegistryRef
++ \inqmlmodule QtQml.DesignSupport
++ \ingroup qmldesignsupport_qml
++ \inherits AbstractObjectRegistryRef
++ \brief This type is used to access an object registered with ObjectRegistry type.
++
++ Example usage:
++ \snippet doc_src_objectregistry.cpp 0
++ \codeline
++ \snippet doc_src_objectregistry.cpp 1
++
++ \sa ObjectRegistry, AbstractObjectRegistryRef::key
++ */
++
++ /*!
++ \property QObjectRegistryRef::object
++ \brief The object referenced by this instance.
++
++ If multiple objects are registered with the same key, the object referenced by this instance
++ is an unspecified one of among them. Use QMultiObjectRegistryRef instead in that case.
++
++ \sa ObjectRegistry, QAbstractObjectRegistryRef::key
++ */
++
++ /*!
++ \qmlproperty QtObject ObjectRegistryRef::object
++
++ This property specifies the object referenced by this instance.
++
++ If multiple objects are registered with the same key, this instance references an unspecified
++ object from that group. In this case, use QMultiObjectRegistryRef.
++
++ \sa ObjectRegistry, AbstractObjectRegistryRef::key
++ */
++
++ /*!
++ Constructs QObjectRegistryRef instance with \a parent.
++
++ \note Use this constructor only if the correct QML engine resolves automatically when the key
++ is set. This generally does not happen when creating an instance of this class from C++.
++ It is recommended to use one of the constructors that take a QML engine pointer as a parameter.
++
++ \sa qmlEngine(), QAbstractObjectRegistryRef::key
++ */
++ QObjectRegistryRef::QObjectRegistryRef(QObject *parent)
++ : QAbstractObjectRegistryRef(*new QObjectRegistryRefPrivate(), parent)
++ {}
++
++ /*!
++ Constructs QObjectRegistryRef instance with QML \a engine and \a parent.
++ All registrations are scoped to the specified QML engine.
++
++ \sa QAbstractObjectRegistryRef::key
++ */
++ QObjectRegistryRef::QObjectRegistryRef(QQmlEngine *engine, QObject *parent)
++ : QAbstractObjectRegistryRef(*new QObjectRegistryRefPrivate(engine), parent)
++ {}
++
++ /*!
++ Constructs QObjectRegistryRef instance with QML \a engine, \a key and \a parent.
++ All registrations are scoped to the specified QML engine.
++
++ \sa QAbstractObjectRegistryRef::key
++ */
++ QObjectRegistryRef::QObjectRegistryRef(QQmlEngine *engine, const QString &key, QObject *parent)
++ : QAbstractObjectRegistryRef(*new QObjectRegistryRefPrivate(engine), parent)
++ {
++ setKey(key);
++ }
++
++ QObjectRegistryRef::~QObjectRegistryRef() = default;
++
++ QObject *QObjectRegistryRef::object() const
++ {
++ Q_D(const QObjectRegistryRef);
++
++ return d->m_object;
++ }
++
++ /*!
++ \reimp
++ */
++ bool QObjectRegistryRef::event(QEvent *event)
++ {
++ return QAbstractObjectRegistryRef::event(event);
++ }
++
++ void QObjectRegistryRefPrivate::handleInitialObjects()
++ {
++ if (!registry())
++ return;
++
++ QList<QObject *> objects = registry()->objects(key()).values();
++
++ if (objects.size() > 1)
++ printMultiWarning();
++
++ QObject *newObject = nullptr;
++
++ if (!objects.isEmpty())
++ newObject = *objects.cbegin();
++
++ setObject(newObject);
++ }
++
++ void QObjectRegistryRefPrivate::handleObjectAdded(QObject *obj)
++ {
++ if (m_object && m_object != obj) {
++ printMultiWarning();
++ return;
++ }
++ setObject(obj);
++ }
++
++ void QObjectRegistryRefPrivate::handleObjectRemoved(QObject *obj)
++ {
++ if (m_object != obj)
++ return;
++ setObject(nullptr);
++ }
++
++ QObjectRegistryRefPrivate::QObjectRegistryRefPrivate(QQmlEngine *engine)
++ : QAbstractObjectRegistryRefPrivate(engine)
++ {}
++
++ void QObjectRegistryRefPrivate::setObject(QObject *obj)
++ {
++ Q_Q(QObjectRegistryRef);
++
++ if (obj == m_object)
++ return;
++
++ m_object = obj;
++ emit q->objectChanged(m_object);
++ }
++
++ void QObjectRegistryRefPrivate::printMultiWarning() const
++ {
++ Q_Q(const QObjectRegistryRef);
++
++ qmlWarning(q) << "ObjectRegistryRef found multiple objects registered with the same key ("
++ << q->key()
++ << "). MultiObjectRegistryRef should be used instead.";
++ }
++
++ QT_END_NAMESPACE