locker.h

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/*
 *  RPLIDAR SDK
 *
 *  Copyright (c) 2009 - 2014 RoboPeak Team
 *  http://www.robopeak.com
 *  Copyright (c) 2014 - 2019 Shanghai Slamtec Co., Ltd.
 *  http://www.slamtec.com
 *
 */
/*
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, 
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, 
 *    this list of conditions and the following disclaimer in the documentation 
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#pragma once
namespace rp{ namespace hal{ 

class Locker
{
public:
    enum LOCK_STATUS
    {
        LOCK_OK = 1,
        LOCK_TIMEOUT = -1,
        LOCK_FAILED = 0
    };

    Locker(){
#ifdef _WIN32
        _lock = NULL;
#endif
        init();
    }

    ~Locker()
    {
        release();
    }

    Locker::LOCK_STATUS lock(unsigned long timeout = 0xFFFFFFFF)
    {
#ifdef _WIN32
        switch (WaitForSingleObject(_lock, timeout==0xFFFFFFF?INFINITE:(DWORD)timeout))
        {
        case WAIT_ABANDONED:
            return LOCK_FAILED;
        case WAIT_OBJECT_0:
            return LOCK_OK;
        case WAIT_TIMEOUT:
            return LOCK_TIMEOUT;
        }

#else
#ifdef _MACOS
        if (timeout !=0 ) {
            if (pthread_mutex_lock(&_lock) == 0) return LOCK_OK;
        }
#else
        if (timeout == 0xFFFFFFFF){
            if (pthread_mutex_lock(&_lock) == 0) return LOCK_OK;
        }
#endif
        else if (timeout == 0)
        {
            if (pthread_mutex_trylock(&_lock) == 0) return LOCK_OK;
        }
#ifndef _MACOS
        else
        {
            timespec wait_time;
            timeval now;
            gettimeofday(&now,NULL);

            wait_time.tv_sec = timeout/1000 + now.tv_sec;
            wait_time.tv_nsec = (timeout%1000)*1000000 + now.tv_usec*1000;
        
            if (wait_time.tv_nsec >= 1000000000)
            {
               ++wait_time.tv_sec;
               wait_time.tv_nsec -= 1000000000;
            }
            switch (pthread_mutex_timedlock(&_lock,&wait_time))
            {
            case 0:
                return LOCK_OK;
            case ETIMEDOUT:
                return LOCK_TIMEOUT;
            }
        }
#endif
#endif

        return LOCK_FAILED;
    }


    void unlock()
    {
#ifdef _WIN32
        ReleaseMutex(_lock);
#else
        pthread_mutex_unlock(&_lock);
#endif
    }

#ifdef _WIN32
    HANDLE getLockHandle()
    {
        return _lock;
    }
#else
    pthread_mutex_t *getLockHandle()
    {
        return &_lock;
    }
#endif



protected:
    void    init()
    {
#ifdef _WIN32
        _lock = CreateMutex(NULL,FALSE,NULL);
#else
        pthread_mutex_init(&_lock, NULL);
#endif
    }

    void    release()
    {
        unlock(); //force unlock before release
#ifdef _WIN32

        if (_lock) CloseHandle(_lock);
        _lock = NULL;
#else
        pthread_mutex_destroy(&_lock);
#endif
    }

#ifdef _WIN32
    HANDLE  _lock;
#else
    pthread_mutex_t _lock;
#endif
};

class AutoLocker
{
public :
    AutoLocker(Locker &l): _binded(l)
    {
        _binded.lock();
    }

    void forceUnlock() {
        _binded.unlock();
    }
    ~AutoLocker() {_binded.unlock();}
    Locker & _binded;
};


}}