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/**
* @file job_queue.c
*
* @brief Job-Queue based on linked_list_t
*
*/
/*
* Copyright (C) 2005 Jan Hutter, Martin Willi
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program 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 General Public License
* for more details.
*/
#include <stdlib.h>
#include <pthread.h>
#include "job_queue.h"
#include "../utils/allocator.h"
#include "../utils/linked_list.h"
/**
* @brief Private Variables and Functions of job_queue class
*
*/
typedef struct private_job_queue_s private_job_queue_t;
struct private_job_queue_s {
job_queue_t public;
/**
* The jobs are stored in a linked list
*/
linked_list_t *list;
/**
* access to linked_list is locked through this mutex
*/
pthread_mutex_t mutex;
/**
* If the queue is empty a thread has to wait
* This condvar is used to wake up such a thread
*/
pthread_cond_t condvar;
};
/**
* @brief implements function get_count of job_queue_t
*/
static int get_count(private_job_queue_t *this)
{
int count;
pthread_mutex_lock(&(this->mutex));
count = this->list->get_count(this->list);
pthread_mutex_unlock(&(this->mutex));
return count;
}
/**
* @brief implements function get of job_queue_t
*/
static status_t get(private_job_queue_t *this, job_t **job)
{
int oldstate;
pthread_mutex_lock(&(this->mutex));
/* go to wait while no jobs available */
while(this->list->get_count(this->list) == 0)
{
/* add mutex unlock handler for cancellation, enable cancellation */
pthread_cleanup_push((void(*)(void*))pthread_mutex_unlock, (void*)&(this->mutex));
pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
pthread_cond_wait( &(this->condvar), &(this->mutex));
/* reset cancellation, remove mutex-unlock handler (without executing) */
pthread_setcancelstate(oldstate, NULL);
pthread_cleanup_pop(0);
}
this->list->remove_first(this->list,(void **) job);
pthread_mutex_unlock(&(this->mutex));
return SUCCESS;
}
/**
* @brief implements function add of job_queue_t
*/
static status_t add(private_job_queue_t *this, job_t *job)
{
pthread_mutex_lock(&(this->mutex));
this->list->insert_last(this->list,job);
pthread_cond_signal( &(this->condvar));
pthread_mutex_unlock(&(this->mutex));
return SUCCESS;
}
/**
* @brief implements function destroy of job_queue_t
*
*/
static status_t job_queue_destroy (private_job_queue_t *this)
{
while (this->list->get_count(this->list) > 0)
{
job_t *job;
if (this->list->remove_first(this->list,(void *) &job) != SUCCESS)
{
this->list->destroy(this->list);
break;
}
job->destroy_all(job);
}
this->list->destroy(this->list);
pthread_mutex_destroy(&(this->mutex));
pthread_cond_destroy(&(this->condvar));
allocator_free(this);
return SUCCESS;
}
/*
*
* Documented in header
*/
job_queue_t *job_queue_create()
{
linked_list_t *linked_list = linked_list_create();
if (linked_list == NULL)
{
return NULL;
}
private_job_queue_t *this = allocator_alloc_thing(private_job_queue_t);
if (this == NULL)
{
linked_list->destroy(linked_list);
return NULL;
}
this->public.get_count = (int(*)(job_queue_t*))get_count;
this->public.get = (status_t(*)(job_queue_t*, job_t**))get;
this->public.add = (status_t(*)(job_queue_t*, job_t*))add;
this->public.destroy = (status_t(*)(job_queue_t*))job_queue_destroy;
this->list = linked_list;
pthread_mutex_init(&(this->mutex), NULL);
pthread_cond_init(&(this->condvar), NULL);
return (&this->public);
}
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