mutex.hpp

/*
    Copyright (c) 2007-2014 Contributors as noted in the AUTHORS file

    This file is part of 0MQ.

    0MQ is free software; you can redistribute it and/or modify it under
    the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    0MQ is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef __ZMQ_MUTEX_HPP_INCLUDED__
#define __ZMQ_MUTEX_HPP_INCLUDED__

#include "platform.hpp"
#include "err.hpp"

//  Mutex class encapsulates OS mutex in a platform-independent way.

#ifdef ZMQ_HAVE_WINDOWS

#include "windows.hpp"

namespace zmq
{

    class mutex_t
    {
    public:
        inline mutex_t ()
        {
            InitializeCriticalSection (&cs);
        }

        inline ~mutex_t ()
        {
            DeleteCriticalSection (&cs);
        }

        inline void lock ()
        {
            EnterCriticalSection (&cs);
        }

        inline bool try_lock ()
        {
            return (TryEnterCriticalSection (&cs)) ? true : false;
        }

        inline void unlock ()
        {
            LeaveCriticalSection (&cs);
        }

    private:

        CRITICAL_SECTION cs;

        //  Disable copy construction and assignment.
        mutex_t (const mutex_t&);
        void operator = (const mutex_t&);
    };

}

#else

#include <pthread.h>

namespace zmq
{

    class mutex_t
    {
    public:
        inline mutex_t ()
        {
            int rc = pthread_mutex_init (&mutex, NULL);
            posix_assert (rc);
        }

        inline ~mutex_t ()
        {
            int rc = pthread_mutex_destroy (&mutex);
            posix_assert (rc);
        }

        inline void lock ()
        {
            int rc = pthread_mutex_lock (&mutex);
            posix_assert (rc);
        }

        inline bool try_lock ()
        {
            int rc = pthread_mutex_trylock (&mutex);
            if (rc == EBUSY)
                return false;

            posix_assert (rc);
            return true;
        }

        inline void unlock ()
        {
            int rc = pthread_mutex_unlock (&mutex);
            posix_assert (rc);
        }

    private:

        pthread_mutex_t mutex;

        // Disable copy construction and assignment.
        mutex_t (const mutex_t&);
        const mutex_t &operator = (const mutex_t&);
    };

}

#endif


namespace zmq
{
    struct scoped_lock_t
    {
        scoped_lock_t (mutex_t& mutex_)
            : mutex (mutex_)
        {
            mutex.lock ();
        }

        ~scoped_lock_t ()
        {
            mutex.unlock ();
        }

    private:

        mutex_t& mutex;

        // Disable copy construction and assignment.
        scoped_lock_t (const scoped_lock_t&);
        const scoped_lock_t &operator = (const scoped_lock_t&);
    };
}

#endif