/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
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** 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
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** following information to ensure the GNU Lesser General Public License
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****************************************************************************/

#ifndef QSHAREDMEMORY_H
#define QSHAREDMEMORY_H

#include <QtCore/qobject.h>

QT_BEGIN_NAMESPACE


#ifndef QT_NO_SHAREDMEMORY

class QSharedMemoryPrivate;

class Q_CORE_EXPORT QSharedMemory : public QObject
{
    Q_OBJECT
    Q_DECLARE_PRIVATE(QSharedMemory)

public:
    enum AccessMode
    {
        ReadOnly,
        ReadWrite
    };

    enum SharedMemoryError
    {
        NoError,
        PermissionDenied,
        InvalidSize,
        KeyError,
        AlreadyExists,
        NotFound,
        LockError,
        OutOfResources,
        UnknownError
    };

    QSharedMemory(QObject *parent = 0);
    QSharedMemory(const QString &key, QObject *parent = 0);
    ~QSharedMemory();

    void setKey(const QString &key);
    QString key() const;
    void setNativeKey(const QString &key);
    QString nativeKey() const;

    bool create(int size, AccessMode mode = ReadWrite);
    int size() const;

    bool attach(AccessMode mode = ReadWrite);
    bool isAttached() const;
    bool detach();

    void *data();
    const void* constData() const;
    const void *data() const;

#ifndef QT_NO_SYSTEMSEMAPHORE
    bool lock();
    bool unlock();
#endif

    SharedMemoryError error() const;
    QString errorString() const;

private:
    Q_DISABLE_COPY(QSharedMemory)
};

#endif // QT_NO_SHAREDMEMORY

QT_END_NAMESPACE

#endif // QSHAREDMEMORY_H

