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****************************************************************************/

#ifndef QREADWRITELOCK_H

#define QREADWRITELOCK_H

#include <QtCore/qglobal.h>

#include <limits.h> // ### Qt 5: remove

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

QT_MODULE(Core)

#ifndef QT_NO_THREAD

struct QReadWriteLockPrivate;

class Q_CORE_EXPORT QReadWriteLock

{

public:

    enum RecursionMode { NonRecursive, Recursive };

    QReadWriteLock(); // ### Qt 5: merge with below

    QReadWriteLock(RecursionMode recursionMode);

    ~QReadWriteLock();

    void lockForRead();

    bool tryLockForRead();

    bool tryLockForRead(int timeout);

    void lockForWrite();

    bool tryLockForWrite();

    bool tryLockForWrite(int timeout);

    void unlock();

private:

    Q_DISABLE_COPY(QReadWriteLock)

    QReadWriteLockPrivate *d;

    friend class QWaitCondition;

};

#if defined(Q_CC_MSVC)

#pragma warning( push )

#pragma warning( disable : 4312 ) // ignoring the warning from /Wp64

#endif

class Q_CORE_EXPORT QReadLocker

{

public:

    inline QReadLocker(QReadWriteLock *readWriteLock);

    inline ~QReadLocker()

    { unlock(); }

    inline void unlock()

    {

        if (q_lock) {

            if ((q_val & quintptr(1u)) == quintptr(1u)) {

                q_val &= ~quintptr(1u);

                q_lock->unlock();

            }

        }

    }

    inline void relock()

    {

        if (q_lock) {

            if ((q_val & quintptr(1u)) == quintptr(0u)) {

                q_lock->lockForRead();

                q_val |= quintptr(1u);

            }

        }

    }

    inline QReadWriteLock *readWriteLock() const

    { return reinterpret_cast<QReadWriteLock *>(q_val & ~quintptr(1u)); }

private:

    Q_DISABLE_COPY(QReadLocker)

    union {

        QReadWriteLock *q_lock;

        quintptr q_val;

    };

};

inline QReadLocker::QReadLocker(QReadWriteLock *areadWriteLock)

    : q_lock(areadWriteLock)

{

    Q_ASSERT_X((q_val & quintptr(1u)) == quintptr(0),

               "QReadLocker", "QReadWriteLock pointer is misaligned");

    relock();

}

class Q_CORE_EXPORT QWriteLocker

{

public:

    inline QWriteLocker(QReadWriteLock *readWriteLock);

    inline ~QWriteLocker()

    { unlock(); }

    inline void unlock()

    {

        if (q_lock) {

            if ((q_val & quintptr(1u)) == quintptr(1u)) {

                q_val &= ~quintptr(1u);

                q_lock->unlock();

            }

        }

    }

    inline void relock()

    {

        if (q_lock) {

            if ((q_val & quintptr(1u)) == quintptr(0u)) {

                q_lock->lockForWrite();

                q_val |= quintptr(1u);

            }

        }

    }

    inline QReadWriteLock *readWriteLock() const

    { return reinterpret_cast<QReadWriteLock *>(q_val & ~quintptr(1u)); }

private:

    Q_DISABLE_COPY(QWriteLocker)

    union{

        QReadWriteLock *q_lock;

        quintptr q_val;

    };

};

inline QWriteLocker::QWriteLocker(QReadWriteLock *areadWriteLock)

    : q_lock(areadWriteLock)

{

    Q_ASSERT_X((q_val & quintptr(1u)) == quintptr(0),

               "QWriteLocker", "QReadWriteLock pointer is misaligned");

    relock();

}

#if defined(Q_CC_MSVC)

#pragma warning( pop )

#endif

#else // QT_NO_THREAD

class Q_CORE_EXPORT QReadWriteLock

{

public:

    enum RecursionMode { NonRecursive, Recursive };

    inline explicit QReadWriteLock(RecursionMode = NonRecursive) { }

    inline ~QReadWriteLock() { }

    static inline void lockForRead() { }

    static inline bool tryLockForRead() { return true; }

    static inline bool tryLockForRead(int timeout) { Q_UNUSED(timeout); return true; }

    static inline void lockForWrite() { }

    static inline bool tryLockForWrite() { return true; }

    static inline bool tryLockForWrite(int timeout) { Q_UNUSED(timeout); return true; }

    static inline void unlock() { }

private:

    Q_DISABLE_COPY(QReadWriteLock)

};

class Q_CORE_EXPORT QReadLocker

{

public:

    inline QReadLocker(QReadWriteLock *) { }

    inline ~QReadLocker() { }

    static inline void unlock() { }

    static inline void relock() { }

    static inline QReadWriteLock *readWriteLock() { return 0; }

private:

    Q_DISABLE_COPY(QReadLocker)

};

class Q_CORE_EXPORT QWriteLocker

{

public:

    inline explicit QWriteLocker(QReadWriteLock *) { }

    inline ~QWriteLocker() { }

    static inline void unlock() { }

    static inline void relock() { }

    static inline QReadWriteLock *readWriteLock() { return 0; }

private:

    Q_DISABLE_COPY(QWriteLocker)

};

#endif // QT_NO_THREAD

QT_END_NAMESPACE

QT_END_HEADER

#endif // QREADWRITELOCK_H