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/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** 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 Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/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 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef QREFCOUNT_H
#define QREFCOUNT_H
#include <QtCore/qatomic.h>
QT_BEGIN_HEADER
QT_BEGIN_NAMESPACE
namespace QtPrivate
{
class RefCount
{
public:
inline bool ref() Q_DECL_NOTHROW {
int count = atomic.load();
if (count == 0) // !isSharable
return false;
if (count != -1) // !isStatic
atomic.ref();
return true;
}
inline bool deref() Q_DECL_NOTHROW {
int count = atomic.load();
if (count == 0) // !isSharable
return false;
if (count == -1) // isStatic
return true;
return atomic.deref();
}
bool setSharable(bool sharable) Q_DECL_NOTHROW
{
Q_ASSERT(!isShared());
if (sharable)
return atomic.testAndSetRelaxed(0, 1);
else
return atomic.testAndSetRelaxed(1, 0);
}
bool isStatic() const Q_DECL_NOTHROW
{
// Persistent object, never deleted
return atomic.load() == -1;
}
bool isSharable() const Q_DECL_NOTHROW
{
// Sharable === Shared ownership.
return atomic.load() != 0;
}
bool isShared() const Q_DECL_NOTHROW
{
int count = atomic.load();
return (count != 1) && (count != 0);
}
void initializeOwned() Q_DECL_NOTHROW { atomic.store(1); }
void initializeUnsharable() Q_DECL_NOTHROW { atomic.store(0); }
QBasicAtomicInt atomic;
};
}
#define Q_REFCOUNT_INITIALIZE_STATIC { Q_BASIC_ATOMIC_INITIALIZER(-1) }
QT_END_NAMESPACE
QT_END_HEADER
#endif
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