/****************************************************************************
**
** Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Qt Software Information (qt-info@nokia.com)
**
** This file is part of the QtCore module of the Qt Toolkit.
**
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** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License versions 2.0 or 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 GNU General Public Licensing requirements will be met:
** http://www.fsf.org/licensing/licenses/info/GPLv2.html and
** http://www.gnu.org/copyleft/gpl.html.  In addition, as a special
** exception, Nokia gives you certain additional rights. These rights
** are described in the Nokia Qt GPL Exception version 1.3, included in
** the file GPL_EXCEPTION.txt in this package.
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****************************************************************************/

#ifndef QSHAREDMEMORY_P_H
#define QSHAREDMEMORY_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 "qsharedmemory.h"

#ifdef QT_NO_SHAREDMEMORY
# ifndef QT_NO_SYSTEMSEMAPHORE
namespace QSharedMemoryPrivate
{
    int createUnixKeyFile(const QString &fileName);
    QString makePlatformSafeKey(const QString &key,
            const QString &prefix = QLatin1String("qipc_sharedmemory_"));
}
#endif
#else

#include "qsystemsemaphore.h"
#include "private/qobject_p.h"

#ifdef Q_OS_WIN
#include <qt_windows.h>
#else
#include <sys/sem.h>
#endif

QT_BEGIN_NAMESPACE

#ifndef QT_NO_SYSTEMSEMAPHORE
/*!
  Helper class
  */
class QSharedMemoryLocker
{

public:
    inline QSharedMemoryLocker(QSharedMemory *sharedMemory) : q_sm(sharedMemory)
    {
        Q_ASSERT(q_sm);
    }

    inline ~QSharedMemoryLocker()
    {
        if (q_sm)
            q_sm->unlock();
    }

    inline bool lock()
    {
        if (q_sm && q_sm->lock())
            return true;
        q_sm = 0;
        return false;
    }

private:
    QSharedMemory *q_sm;
};
#endif // QT_NO_SYSTEMSEMAPHORE

class Q_AUTOTEST_EXPORT QSharedMemoryPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QSharedMemory)

public:
    QSharedMemoryPrivate();

    void *memory;
    int size;
    QString key;
    QSharedMemory::SharedMemoryError error;
    QString errorString;
#ifndef QT_NO_SYSTEMSEMAPHORE
    QSystemSemaphore systemSemaphore;
    bool lockedByMe;
#endif

    static int createUnixKeyFile(const QString &fileName);
    static QString makePlatformSafeKey(const QString &key,
            const QString &prefix = QLatin1String("qipc_sharedmemory_"));
#ifdef Q_OS_WIN
    HANDLE handle();
#else
    key_t handle();
#endif
    bool initKey();
    bool cleanHandle();
    bool create(int size);
    bool attach(QSharedMemory::AccessMode mode);
    bool detach();

    void setErrorString(const QString &function);

#ifndef QT_NO_SYSTEMSEMAPHORE
    bool tryLocker(QSharedMemoryLocker *locker, const QString function) {
        if (!locker->lock()) {
            errorString = QSharedMemory::tr("%1: unable to lock").arg(function);
            error = QSharedMemory::LockError;
            return false;
        }
        return true;
    }
#endif // QT_NO_SYSTEMSEMAPHORE

private:
#ifdef Q_OS_WIN
    HANDLE hand;
#else
    key_t unix_key;
#endif
};

QT_END_NAMESPACE

#endif // QT_NO_SHAREDMEMORY

#endif // QSHAREDMEMORY_P_H

