qqmlanybinding_p.h

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// Copyright (C) 2021 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
 
#ifndef QQMLANYBINDINGPTR_P_H
#define QQMLANYBINDINGPTR_P_H
 
//
//  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.
//
 
#include <qqmlproperty.h>
#include <private/qqmlpropertybinding_p.h>
#include <private/qqmlbinding_p.h>
 
QT_BEGIN_NAMESPACE
 
// Fully inline so that subsequent prop.isBindable check might get ellided.
 
class QQmlAnyBinding {
public:
 
    constexpr QQmlAnyBinding() noexcept = default;
    QQmlAnyBinding(std::nullptr_t) : d(static_cast<QQmlAbstractBinding *>(nullptr)) {}
 
    static QQmlAnyBinding ofProperty(const QQmlProperty &prop) {
        QQmlAnyBinding binding;
        if (prop.isBindable()) {
            QUntypedBindable bindable = prop.property().bindable(prop.object());
            binding = bindable.binding();
        } else {
            binding = QQmlPropertyPrivate::binding(prop);
        }
        return binding;
    }
 
    static QQmlAnyBinding ofProperty(QObject *object, QQmlPropertyIndex index)
    {
        QQmlAnyBinding binding;
        Q_ASSERT(object);
        QQmlData *data = QQmlData::get(object, true);
        auto coreIndex = index.coreIndex();
        // we don't support bindable properties on value types so far
        if (!index.hasValueTypeIndex() && data->propertyCache->property(coreIndex)->isBindable()) {
            auto metaProp = object->metaObject()->property(coreIndex);
            QUntypedBindable bindable = metaProp.bindable(object);
            binding = bindable.binding();
        } else {
            binding = QQmlPropertyPrivate::binding(object, index);
        }
        return binding;
    }
 
    static QQmlAnyBinding takeFrom(const QQmlProperty &prop)
    {
        QQmlAnyBinding binding;
        if (prop.isBindable()) {
            QUntypedBindable bindable = prop.property().bindable(prop.object());
            binding = bindable.takeBinding();
        } else {
            auto qmlBinding = QQmlPropertyPrivate::binding(prop);
            if (qmlBinding) {
                binding = qmlBinding; // this needs to run before removeFromObject, else the refcount might reach zero
                qmlBinding->setEnabled(false, QQmlPropertyData::DontRemoveBinding | QQmlPropertyData::BypassInterceptor);
                qmlBinding->removeFromObject();
            }
        }
        return binding;
    }
 
    static QQmlAnyBinding createFromFunction(const QQmlProperty &prop, QV4::Function *function,
                                                  QObject *obj, const QQmlRefPointer<QQmlContextData> &ctxt,
                                                  QV4::ExecutionContext *scope)
    {
        QQmlAnyBinding binding;
        auto propPriv = QQmlPropertyPrivate::get(prop);
        if (prop.isBindable()) {
            auto index = QQmlPropertyIndex(propPriv->core.coreIndex(), -1);
            binding = QQmlPropertyBinding::create(&propPriv->core,
                                                  function, obj, ctxt,
                                                  scope, prop.object(), index);
        } else {
            auto qmlBinding = QQmlBinding::create(&propPriv->core, function, obj, ctxt, scope);
            qmlBinding->setTarget(prop);
            binding = qmlBinding;
        }
        return binding;
    }
 
    static QQmlAnyBinding createFromScriptString(const QQmlProperty &prop, const QQmlScriptString &script,
                                                  QObject *obj,  QQmlContext *ctxt)
    {
        QQmlAnyBinding binding;
        auto propPriv = QQmlPropertyPrivate::get(prop);
        if (prop.isBindable()) {
            auto index = QQmlPropertyIndex(propPriv->core.coreIndex(), -1);
            binding = QQmlPropertyBinding::createFromScriptString(&propPriv->core, script, obj, ctxt, prop.object(), index);
        } else {
            auto qmlBinding = QQmlBinding::create(&propPriv->core, script, obj, ctxt);
            qmlBinding->setTarget(prop);
            binding = qmlBinding;
        }
        return binding;
    }
 
 
    static void removeBindingFrom(QQmlProperty &prop)
    {
        if (prop.isBindable())
            prop.property().bindable(prop.object()).takeBinding();
        else
            QQmlPropertyPrivate::removeBinding(prop);
    }
 
    static QQmlAnyBinding createFromCodeString(const QQmlProperty &prop, const QString& code, QObject *obj, const QQmlRefPointer<QQmlContextData> &ctxt, const QString &url, quint16 lineNumber) {
        QQmlAnyBinding binding;
        auto propPriv = QQmlPropertyPrivate::get(prop);
        if (prop.isBindable()) {
            auto index = QQmlPropertyIndex(propPriv->core.coreIndex(), -1);
            binding = QQmlPropertyBinding::createFromCodeString(&propPriv->core,
                                                                code, obj, ctxt,
                                                                url, lineNumber,
                                                                prop.object(), index);
        } else {
            auto qmlBinding = QQmlBinding::create(&propPriv->core, code, obj, ctxt, url, lineNumber);
            qmlBinding->setTarget(prop);
            binding = qmlBinding;
        }
        return binding;
    }
 
    static QQmlAnyBinding createTranslationBinding(const QQmlProperty &prop, const QQmlRefPointer<QV4::ExecutableCompilationUnit> &compilationUnit, const QV4::CompiledData::Binding *translationBinding, QObject *scopeObject=nullptr, QQmlRefPointer<QQmlContextData> context={})
    {
        QQmlAnyBinding binding;
        auto propPriv = QQmlPropertyPrivate::get(prop);
        if (prop.isBindable()) {
            binding = QQmlTranslationPropertyBinding::create(&propPriv->core, compilationUnit, translationBinding);
        } else {
            auto qmlBinding = QQmlBinding::createTranslationBinding(compilationUnit, translationBinding, scopeObject, context);
            binding = qmlBinding;
            qmlBinding->setTarget(prop);
        }
        return binding;
    }
 
    enum InterceptorMode : bool {
        IgnoreInterceptors,
        RespectInterceptors
    };
 
    void installOn(const QQmlProperty &target, InterceptorMode mode = IgnoreInterceptors)
    {
        Q_ASSERT(!d.isNull());
        if (isAbstractPropertyBinding()) {
            auto abstractBinding = asAbstractBinding();
            Q_ASSERT(abstractBinding->targetObject() == target.object() || QQmlPropertyPrivate::get(target)->core.isAlias());
            Q_ASSERT(!target.isBindable());
            if (mode == IgnoreInterceptors)
                QQmlPropertyPrivate::setBinding(abstractBinding, QQmlPropertyPrivate::None, QQmlPropertyData::DontRemoveBinding | QQmlPropertyData::BypassInterceptor);
            else
                QQmlPropertyPrivate::setBinding(abstractBinding);
        } else {
            Q_ASSERT(target.isBindable());
            QUntypedBindable bindable;
            void *argv[] = {&bindable};
            if (mode == IgnoreInterceptors) {
                target.object()->qt_metacall(QMetaObject::BindableProperty, target.index(), argv);
            } else {
                QMetaObject::metacall(target.object(), QMetaObject::BindableProperty, target.index(), argv);
            }
            bindable.setBinding(asUntypedPropertyBinding());
        }
    }
 
    bool hasError() {
        if (isAbstractPropertyBinding()) {
            auto abstractBinding = asAbstractBinding();
            if (abstractBinding->kind() != QQmlAbstractBinding::QmlBinding)
                return false;
            return static_cast<QQmlBinding *>(abstractBinding)->hasError();
        } else {
            return asUntypedPropertyBinding().error().hasError();
        }
    }
 
    QQmlAnyBinding &operator=(std::nullptr_t)
    {
        clear();
        return *this;
    }
 
    operator bool() const{
        return !d.isNull();
    }
 
    bool isAbstractPropertyBinding() const
    { return d.isT1(); }
 
    bool isUntypedPropertyBinding() const
    { return d.isT2(); }
 
    QUntypedPropertyBinding asUntypedPropertyBinding() const
    {
        if (d.isT1()  || d.isNull())
            return {};
        auto priv = d.asT2();
        return QUntypedPropertyBinding {priv};
    }
 
    QQmlAbstractBinding *asAbstractBinding() const
    {
        if (d.isT2() || d.isNull())
            return nullptr;
        return d.asT1();
    }
 
    void refresh()
    {
        if (d.isNull())
            return;
        if (d.isT1()) {
            auto binding = static_cast<QQmlBinding *>(d.asT1());
            binding->setEnabledFlag(true);
            binding->refresh();
        } else {
            auto bindingPriv = d.asT2();
            PendingBindingObserverList bindingObservers;
            bindingPriv->evaluateRecursive(bindingObservers);
            bindingPriv->notifyNonRecursive(bindingObservers);
        }
 
    }
 
    QQmlAnyBinding &operator=(QQmlAbstractBinding *binding)
    {
        clear();
        if (binding) {
            d = binding;
            binding->ref.ref();
        }
        return *this;
    }
 
    QQmlAnyBinding &operator=(const QQmlAbstractBinding::Ptr &binding)
    {
        clear();
        if (binding) {
            d = binding.data();
            binding->ref.ref();
        }
        return *this;
    }
 
    QQmlAnyBinding &operator=(QQmlAbstractBinding::Ptr &&binding)
    {
        clear();
        if (binding) {
            d = binding.take();
        }
        return *this;
    }
 
    QQmlAnyBinding &operator=(const QUntypedPropertyBinding &untypedBinding)
    {
        clear();
        auto binding = QPropertyBindingPrivate::get(untypedBinding);
        if (binding) {
            d = binding;
            binding->addRef();
        }
        return *this;
    }
 
    QQmlAnyBinding &operator=(QUntypedPropertyBinding &&untypedBinding)
    {
        clear();
        auto binding = QPropertyBindingPrivate::get(untypedBinding);
        QPropertyBindingPrivatePtr ptr(binding);
        if (binding) {
            d = static_cast<QPropertyBindingPrivate *>(ptr.take());
        }
        return *this;
    }
 
    QQmlAnyBinding(QQmlAnyBinding &&other) noexcept
        : d(std::exchange(other.d, QBiPointer<QQmlAbstractBinding, QPropertyBindingPrivate>()))
    {}
 
    QQmlAnyBinding(const QQmlAnyBinding &other) noexcept { *this = other; }
    QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QQmlAnyBinding)
 
    void swap(QQmlAnyBinding &other) noexcept { d.swap(other.d); }
    friend void swap(QQmlAnyBinding &lhs, QQmlAnyBinding &rhs) noexcept { lhs.swap(rhs); }
 
    QQmlAnyBinding &operator=(const QQmlAnyBinding &other) noexcept
    {
        clear();
        if (auto abstractBinding = other.asAbstractBinding())
            *this = abstractBinding;
        else if (auto untypedBinding = other.asUntypedPropertyBinding(); !untypedBinding.isNull())
            *this = untypedBinding;
        return *this;
    }
 
    friend inline bool operator==(const QQmlAnyBinding &p1, const QQmlAnyBinding &p2)
    {
        return p1.d == p2.d;
    }
 
    friend inline bool operator!=(const QQmlAnyBinding &p1, const QQmlAnyBinding &p2)
    {
        return p1.d != p2.d;
    }
 
    ~QQmlAnyBinding() noexcept { clear(); }
private:
    void clear() noexcept {
        if (d.isNull())
            return;
        if (d.isT1()) {
            QQmlAbstractBinding *qqmlptr = d.asT1();
            if (!qqmlptr->ref.deref())
                delete  qqmlptr;
        } else if (d.isT2()) {
            QPropertyBindingPrivate *priv = d.asT2();
            priv->ref--;
            if (!priv->ref)
                QPropertyBindingPrivate::destroyAndFreeMemory(priv);
        }
        d = static_cast<QQmlAbstractBinding *>(nullptr);
    }
    QBiPointer<QQmlAbstractBinding, QPropertyBindingPrivate> d;
};
 
QT_END_NAMESPACE
 
 
#endif // QQMLANYBINDINGPTR_P_H