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/****************************************************************************
**
** Copyright (C) 2021 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:COMM$
**
** 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.
**
** $QT_END_LICENSE$
**
**
**
**
**
**
**
**
**
**
**
**
**
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**
**
**
****************************************************************************/
#ifndef QREFCOUNT_H
#define QREFCOUNT_H
#include <QtCore/qatomic.h>
QT_BEGIN_NAMESPACE
namespace QtPrivate
{
class RefCount
{
public:
inline bool ref() noexcept {
int count = atomic.loadRelaxed();
#if !defined(QT_NO_UNSHARABLE_CONTAINERS)
if (count == 0) // !isSharable
return false;
#endif
if (count != -1) // !isStatic
atomic.ref();
return true;
}
inline bool deref() noexcept {
int count = atomic.loadRelaxed();
#if !defined(QT_NO_UNSHARABLE_CONTAINERS)
if (count == 0) // !isSharable
return false;
#endif
if (count == -1) // isStatic
return true;
return atomic.deref();
}
#if !defined(QT_NO_UNSHARABLE_CONTAINERS)
bool setSharable(bool sharable) noexcept
{
Q_ASSERT(!isShared());
if (sharable)
return atomic.testAndSetRelaxed(0, 1);
else
return atomic.testAndSetRelaxed(1, 0);
}
bool isSharable() const noexcept
{
// Sharable === Shared ownership.
return atomic.loadRelaxed() != 0;
}
#endif
bool isStatic() const noexcept
{
// Persistent object, never deleted
return atomic.loadRelaxed() == -1;
}
bool isShared() const noexcept
{
int count = atomic.loadRelaxed();
return (count != 1) && (count != 0);
}
void initializeOwned() noexcept { atomic.storeRelaxed(1); }
void initializeUnsharable() noexcept { atomic.storeRelaxed(0); }
QBasicAtomicInt atomic;
};
}
#define Q_REFCOUNT_INITIALIZE_STATIC { Q_BASIC_ATOMIC_INITIALIZER(-1) }
QT_END_NAMESPACE
#endif
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