/** @file ESFSharedEmbeddedQueue.cpp
 *  @brief A producer/consumer queue of ESFEmbeddedListElements
 *
 * Copyright (c) 2009 Yahoo! Inc.
 * The copyrights embodied in the content of this file are licensed by Yahoo! Inc.
 * under the BSD (revised) open source license.
 *
 * Derived from code that is Copyright (c) 2009 Joshua Blatt and offered under both
 * BSD and Apache 2.0 licenses (http://sourceforge.net/projects/sparrowhawk/).
 *
 *
 *    $Author: blattj $
 *    $Date: 2009/05/25 21:51:08 $
 *    $Name:  $
 *    $Revision: 1.3 $
 */

#ifndef ESF_SHARED_EMBEDDED_QUEUE_H
#include <ESFSharedEmbeddedQueue.h>
#endif

ESFSharedEmbeddedQueue::ESFSharedEmbeddedQueue() :
    _isStopped(false), _list() {
#if defined HAVE_PTHREAD_MUTEX_INIT && defined HAVE_PTHREAD_COND_INIT && \
    defined HAVE_PTHREAD_MUTEX_DESTROY && defined HAVE_PTHREAD_COND_DESTROY

    pthread_mutex_init(&_mutex, 0);
    pthread_cond_init(&_signal, 0);

#else
#error "Platform has no mutex or signal initializer"
#endif
}

ESFSharedEmbeddedQueue::~ESFSharedEmbeddedQueue() {
#if defined HAVE_PTHREAD_MUTEX_DESTROY && defined HAVE_PTHREAD_COND_DESTROY

    pthread_mutex_destroy(&_mutex);
    pthread_cond_destroy(&_signal);

#else
#error "Platform has no mutex or signal destructor"
#endif
}

ESFError ESFSharedEmbeddedQueue::push(ESFEmbeddedListElement *element) {
#if defined HAVE_PTHREAD_MUTEX_LOCK && defined HAVE_PTHREAD_MUTEX_UNLOCK && defined HAVE_PTHREAD_COND_SIGNAL

    ESFError error = ESFConvertError(pthread_mutex_lock(&_mutex));

    if (ESF_SUCCESS != error) {
        return error;
    }

    if (_isStopped) {
        pthread_mutex_unlock(&_mutex);

        return ESF_SHUTDOWN;
    }

    _list.addLast(element);

    pthread_mutex_unlock(&_mutex);
    pthread_cond_signal(&_signal);

#else
#error "Platform has no mutex lock, mutex unlock, or cond signal"
#endif

    return ESF_SUCCESS;
}

ESFEmbeddedListElement *ESFSharedEmbeddedQueue::pop(ESFError *result) {
    ESFEmbeddedListElement *tmp = 0;

    if (result) *result = ESF_SUCCESS;

#if defined HAVE_PTHREAD_MUTEX_LOCK && defined HAVE_PTHREAD_MUTEX_UNLOCK && defined HAVE_PTHREAD_COND_WAIT

    ESFError error = ESFConvertError(pthread_mutex_lock(&_mutex));

    if (ESF_SUCCESS != error) {
    	if (result) *result = error;
        return 0;
    }

    do {
        if (_isStopped) {
            break;
        }

        tmp = _list.removeFirst();

        if (tmp) {
            break;
        }

        error = ESFConvertError(pthread_cond_wait(&_signal, &_mutex));

        if (ESF_SUCCESS != error && ESF_INTR != error) {
        	if (result) *result = error;
            return 0;
        }
    } while (0 == tmp);

    pthread_mutex_unlock(&_mutex);

#else
#error "Platform has no mutex lock, mutex unlock, or cond wait"
#endif

    if (tmp) {
    	return tmp;
    }

    if (result) {
    	*result = ESF_SHUTDOWN;
    }

    return 0;
}

void ESFSharedEmbeddedQueue::stop() {
#if defined HAVE_PTHREAD_MUTEX_LOCK && defined HAVE_PTHREAD_MUTEX_UNLOCK && defined HAVE_PTHREAD_COND_BROADCAST

    pthread_mutex_lock(&_mutex);

    _isStopped = true;
    _list.clear(true);

    pthread_mutex_unlock(&_mutex);
    pthread_cond_broadcast(&_signal);

#else
#error "Platform has no mutex lock, mutex unlock, or cond broadcast"
#endif
}