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/****************************************************************************
**
** Copyright (C) 2020 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** 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 https://www.qt.io/terms-conditions. For further
** information use the contact form at https://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.LGPL3 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-3.0.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 (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qpropertybinding_p.h"
#include "qproperty_p.h"
#include <QScopedValueRollback>
#include <QVariant>
QT_BEGIN_NAMESPACE
using namespace QtPrivate;
QPropertyBindingPrivate::~QPropertyBindingPrivate()
{
if (firstObserver)
firstObserver.unlink();
if (!hasStaticObserver)
inlineDependencyObservers.~ObserverArray(); // Explicit because of union.
}
void QPropertyBindingPrivate::unlinkAndDeref()
{
propertyDataPtr = nullptr;
if (!ref.deref())
delete this;
}
void QPropertyBindingPrivate::markDirtyAndNotifyObservers()
{
if (dirty)
return;
dirty = true;
if (firstObserver)
firstObserver.notify(this, propertyDataPtr);
if (hasStaticObserver) {
if (metaType == QMetaType::fromType<bool>()) {
auto propertyPtr = reinterpret_cast<QPropertyBase *>(propertyDataPtr);
bool oldValue = propertyPtr->extraBit();
staticObserverCallback(staticObserver, &oldValue);
} else {
staticObserverCallback(staticObserver, propertyDataPtr);
}
}
}
bool QPropertyBindingPrivate::evaluateIfDirtyAndReturnTrueIfValueChanged()
{
if (!dirty)
return false;
if (updating) {
error = QPropertyBindingError(QPropertyBindingError::BindingLoop);
return false;
}
/*
* Evaluating the binding might lead to the binding being broken. This can
* cause ref to reach zero at the end of the function. However, the
* updateGuard's destructor will then still trigger, trying to set the
* updating bool to its old value
* To prevent this, we create a QPropertyBindingPrivatePtr which ensures
* that the object is still alive when updateGuard's dtor runs.
*/
QPropertyBindingPrivatePtr keepAlive {this};
QScopedValueRollback<bool> updateGuard(updating, true);
BindingEvaluationState evaluationFrame(this);
QPropertyBindingError evalError;
QUntypedPropertyBinding::BindingEvaluationResult result;
bool changed = false;
if (metaType.id() == QMetaType::Bool) {
auto propertyPtr = reinterpret_cast<QPropertyBase *>(propertyDataPtr);
bool newValue = false;
evalError = evaluationFunction(metaType, &newValue);
if (evalError.type() == QPropertyBindingError::NoError) {
bool updateAllowed = true;
if (hasStaticObserver && staticGuardCallback)
updateAllowed = staticGuardCallback(staticObserver, &newValue);
if (updateAllowed && propertyPtr->extraBit() != newValue) {
propertyPtr->setExtraBit(newValue);
changed = true;
}
}
} else {
QVariant resultVariant(metaType.id(), nullptr);
evalError = evaluationFunction(metaType, resultVariant.data());
if (evalError.type() == QPropertyBindingError::NoError) {
int compareResult = 0;
bool updateAllowed = true;
if (hasStaticObserver && staticGuardCallback)
updateAllowed = staticGuardCallback(staticObserver, resultVariant.data());
if (updateAllowed && (!QMetaType::compare(propertyDataPtr, resultVariant.constData(), metaType.id(), &compareResult) || compareResult != 0)) {
changed = true;
metaType.destruct(propertyDataPtr);
metaType.construct(propertyDataPtr, resultVariant.constData());
}
}
}
if (evalError.type() != QPropertyBindingError::NoError)
error = evalError;
dirty = false;
return changed;
}
QUntypedPropertyBinding::QUntypedPropertyBinding() = default;
QUntypedPropertyBinding::QUntypedPropertyBinding(const QMetaType &metaType, QUntypedPropertyBinding::BindingEvaluationFunction function,
const QPropertyBindingSourceLocation &location)
{
d = new QPropertyBindingPrivate(metaType, std::move(function), std::move(location));
}
QUntypedPropertyBinding::QUntypedPropertyBinding(QUntypedPropertyBinding &&other)
: d(std::move(other.d))
{
}
QUntypedPropertyBinding::QUntypedPropertyBinding(const QUntypedPropertyBinding &other)
: d(other.d)
{
}
QUntypedPropertyBinding &QUntypedPropertyBinding::operator=(const QUntypedPropertyBinding &other)
{
d = other.d;
return *this;
}
QUntypedPropertyBinding &QUntypedPropertyBinding::operator=(QUntypedPropertyBinding &&other)
{
d = std::move(other.d);
return *this;
}
QUntypedPropertyBinding::QUntypedPropertyBinding(QPropertyBindingPrivate *priv)
: d(priv)
{
}
QUntypedPropertyBinding::~QUntypedPropertyBinding()
{
}
bool QUntypedPropertyBinding::isNull() const
{
return !d;
}
QPropertyBindingError QUntypedPropertyBinding::error() const
{
if (!d)
return QPropertyBindingError();
return d->bindingError();
}
QMetaType QUntypedPropertyBinding::valueMetaType() const
{
if (!d)
return QMetaType();
return d->valueMetaType();
}
QT_END_NAMESPACE
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