/** * @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 . * * 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 #include #include "allocator.h" #include "job_queue.h" #include "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(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); }