event.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */
/*
 * 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 Event
{
   public:
        enum
        {
                EVENT_OK = 1,
                EVENT_TIMEOUT = 2,
                EVENT_FAILED = 0,
        };

        Event(bool isAutoReset = true, bool isSignal = false)
#ifdef _WIN32
                : _event(nullptr)
#else
                : _is_signalled(isSignal), _isAutoReset(isAutoReset)
#endif
        {
#ifdef _WIN32
                _event = CreateEvent(
                        nullptr, isAutoReset ? FALSE : TRUE, isSignal ? TRUE : FALSE,
                        nullptr);
#else
                pthread_mutex_init(&_cond_locker, nullptr);
                pthread_cond_init(&_cond_var, nullptr);
#endif
        }

        ~Event() { release(); }
        void set(bool isSignal = true)
        {
                if (isSignal)
                {
#ifdef _WIN32
                        SetEvent(_event);
#else
                        pthread_mutex_lock(&_cond_locker);

                        if (_is_signalled == false)
                        {
                                _is_signalled = true;
                                pthread_cond_signal(&_cond_var);
                        }
                        pthread_mutex_unlock(&_cond_locker);
#endif
                }
                else
                {
#ifdef _WIN32
                        ResetEvent(_event);
#else
                        pthread_mutex_lock(&_cond_locker);
                        _is_signalled = false;
                        pthread_mutex_unlock(&_cond_locker);
#endif
                }
        }

        unsigned long wait(unsigned long timeout = 0xFFFFFFFF)
        {
#ifdef _WIN32
                switch (WaitForSingleObject(
                        _event, timeout == 0xFFFFFFF ? INFINITE : (DWORD)timeout))
                {
                        case WAIT_FAILED:
                                return EVENT_FAILED;
                        case WAIT_OBJECT_0:
                                return EVENT_OK;
                        case WAIT_TIMEOUT:
                                return EVENT_TIMEOUT;
                }
                return EVENT_OK;
#else
                unsigned long ans = EVENT_OK;
                pthread_mutex_lock(&_cond_locker);

                if (!_is_signalled)
                {
                        if (timeout == 0xFFFFFFFF)
                        {
                                pthread_cond_wait(&_cond_var, &_cond_locker);
                        }
                        else
                        {
                                timespec wait_time;
                                timeval now;
                                gettimeofday(&now, nullptr);

                                wait_time.tv_sec = timeout / 1000 + now.tv_sec;
                                wait_time.tv_nsec =
                                        (timeout % 1000) * 1000000ULL + now.tv_usec * 1000;

                                if (wait_time.tv_nsec >= 1000000000)
                                {
                                        ++wait_time.tv_sec;
                                        wait_time.tv_nsec -= 1000000000;
                                }
                                switch (pthread_cond_timedwait(
                                        &_cond_var, &_cond_locker, &wait_time))
                                {
                                        case 0:
                                                // signalled
                                                break;
                                        case ETIMEDOUT:
                                                // time up
                                                ans = EVENT_TIMEOUT;
                                                goto _final;
                                                break;
                                        default:
                                                ans = EVENT_FAILED;
                                                goto _final;
                                }
                        }
                }

                assert(_is_signalled);

                if (_isAutoReset)
                {
                        _is_signalled = false;
                }
        _final:
                pthread_mutex_unlock(&_cond_locker);

                return ans;
#endif
        }

   protected:
        void release()
        {
#ifdef _WIN32
                CloseHandle(_event);
#else
                pthread_mutex_destroy(&_cond_locker);
                pthread_cond_destroy(&_cond_var);
#endif
        }

#ifdef _WIN32
        HANDLE _event;
#else
        pthread_cond_t _cond_var;
        pthread_mutex_t _cond_locker;
        bool _is_signalled;
        bool _isAutoReset;
#endif
};
}
}