katie/src/core/thread/qmutex.h

/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Copyright (C) 2016-2019 Ivailo Monev
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** 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 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company 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
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** $QT_END_LICENSE$
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****************************************************************************/

#ifndef QMUTEX_H
#define QMUTEX_H

#include <QtCore/qatomic.h>

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE


#ifndef QT_NO_THREAD

class QMutexPrivate;

class Q_CORE_EXPORT QMutex
{
    friend class QWaitCondition;
    friend class QWaitConditionPrivate;

public:
    enum RecursionMode {
        NonRecursive,
        Recursive
    };

    explicit QMutex(RecursionMode mode = NonRecursive);
    ~QMutex();

    void lock();
    bool tryLock();
    bool tryLock(int timeout);
    void unlock();

private:
    Q_DISABLE_COPY(QMutex)

    QMutexPrivate *d;
};

class Q_CORE_EXPORT QMutexLocker
{
public:
    inline explicit QMutexLocker(QMutex *m)
    {
        Q_ASSERT_X((reinterpret_cast<quintptr>(m) & quintptr(1u)) == quintptr(0),
                   "QMutexLocker", "QMutex pointer is misaligned");
        if (m) {
            m->lock();
            val = reinterpret_cast<quintptr>(m) | quintptr(1u);
        } else {
            val = 0;
        }
    }
    inline ~QMutexLocker() { unlock(); }

    inline void unlock()
    {
        if ((val & quintptr(1u)) == quintptr(1u)) {
            val &= ~quintptr(1u);
            mutex()->unlock();
        }
    }

    inline void relock()
    {
        if (val) {
            if ((val & quintptr(1u)) == quintptr(0u)) {
                mutex()->lock();
                val |= quintptr(1u);
            }
        }
    }

    inline QMutex *mutex() const
    {
        return reinterpret_cast<QMutex *>(val & ~quintptr(1u));
    }

private:
    Q_DISABLE_COPY(QMutexLocker)

    quintptr val;
};


#else // QT_NO_THREAD


class Q_CORE_EXPORT QMutex
{
public:
    enum RecursionMode { NonRecursive, Recursive };

    inline explicit QMutex(RecursionMode mode = NonRecursive) { Q_UNUSED(mode); }
    inline ~QMutex() {}

    static inline void lock() {}
    static inline bool tryLock(int timeout = 0) { Q_UNUSED(timeout); return true; }
    static inline void unlock() {}

private:
    Q_DISABLE_COPY(QMutex)
};

class Q_CORE_EXPORT QMutexLocker
{
public:
    inline explicit QMutexLocker(QMutex *) {}
    inline ~QMutexLocker() {}

    static inline void unlock() {}
    static void relock() {}
    static inline QMutex *mutex() { return Q_NULLPTR; }

private:
    Q_DISABLE_COPY(QMutexLocker)
};

#endif // QT_NO_THREAD

QT_END_NAMESPACE

QT_END_HEADER

#endif // QMUTEX_H