src/charon/charon/queues/job_queue.c

   1 /**
   2  * @file job_queue.c
   3  *
   4  * @brief Implementation of job_queue_t
   5  *
   6  */
   7
   8 /*
   9  * Copyright (C) 2005 Jan Hutter, Martin Willi
  10  * Hochschule fuer Technik Rapperswil
  11  *
  12  * This program is free software; you can redistribute it and/or modify it
  13  * under the terms of the GNU General Public License as published by the
  14  * Free Software Foundation; either version 2 of the License, or (at your
  15  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  19  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  20  * for more details.
  21  */
  22
  23 #include <stdlib.h>
  24 #include <pthread.h>
  25
  26 #include "job_queue.h"
  27
  28 #include <utils/linked_list.h>
  29
  30
  31 typedef struct private_job_queue_t private_job_queue_t;
  32
  33 /**
  34  * @brief Private Variables and Functions of job_queue class
  35  *
  36  */
  37 struct private_job_queue_t {
  38
  39         /**
  40          * public members
  41          */
  42         job_queue_t public;
  43
  44         /**
  45          * The jobs are stored in a linked list
  46          */
  47         linked_list_t *list;
  48
  49         /**
  50          * access to linked_list is locked through this mutex
  51          */
  52         pthread_mutex_t mutex;
  53
  54         /**
  55          * If the queue is empty a thread has to wait
  56          * This condvar is used to wake up such a thread
  57          */
  58         pthread_cond_t condvar;
  59 };
  60
  61
  62 /**
  63  * implements job_queue_t.get_count
  64  */
  65 static int get_count(private_job_queue_t *this)
  66 {
  67         int count;
  68         pthread_mutex_lock(&(this->mutex));
  69         count = this->list->get_count(this->list);
  70         pthread_mutex_unlock(&(this->mutex));
  71         return count;
  72 }
  73
  74 /**
  75  * implements job_queue_t.get
  76  */
  77 static job_t *get(private_job_queue_t *this)
  78 {
  79         int oldstate;
  80         job_t *job;
  81         pthread_mutex_lock(&(this->mutex));
  82         /* go to wait while no jobs available */
  83         while(this->list->get_count(this->list) == 0)
  84         {
  85                 /* add mutex unlock handler for cancellation, enable cancellation */
  86                 pthread_cleanup_push((void(*)(void*))pthread_mutex_unlock, (void*)&(this->mutex));
  87                 pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
  88
  89                 pthread_cond_wait( &(this->condvar), &(this->mutex));
  90
  91                 /* reset cancellation, remove mutex-unlock handler (without executing) */
  92                 pthread_setcancelstate(oldstate, NULL);
  93                 pthread_cleanup_pop(0);
  94         }
  95         this->list->remove_first(this->list,(void **) &job);
  96         pthread_mutex_unlock(&(this->mutex));
  97         return job;
  98 }
  99
 100 /**
 101  * implements function job_queue_t.add
 102  */
 103 static void add(private_job_queue_t *this, job_t *job)
 104 {
 105         pthread_mutex_lock(&(this->mutex));
 106         this->list->insert_last(this->list,job);
 107         pthread_cond_signal( &(this->condvar));
 108         pthread_mutex_unlock(&(this->mutex));
 109 }
 110
 111 /**
 112  * implements job_queue_t.destroy
 113  */
 114 static void job_queue_destroy (private_job_queue_t *this)
 115 {
 116         while (this->list->get_count(this->list) > 0)
 117         {
 118                 job_t *job;
 119                 if (this->list->remove_first(this->list,(void *) &job) != SUCCESS)
 120                 {
 121                         this->list->destroy(this->list);
 122                         break;
 123                 }
 124                 job->destroy_all(job);
 125         }
 126         this->list->destroy(this->list);
 127
 128         pthread_mutex_destroy(&(this->mutex));
 129
 130         pthread_cond_destroy(&(this->condvar));
 131
 132         free(this);
 133 }
 134
 135 /*
 136  *
 137  * Documented in header
 138  */
 139 job_queue_t *job_queue_create(void)
 140 {
 141         private_job_queue_t *this = malloc_thing(private_job_queue_t);
 142
 143         this->public.get_count = (int(*)(job_queue_t*))get_count;
 144         this->public.get = (job_t*(*)(job_queue_t*))get;
 145         this->public.add = (void(*)(job_queue_t*, job_t*))add;
 146         this->public.destroy = (void(*)(job_queue_t*))job_queue_destroy;
 147
 148         this->list = linked_list_create();
 149         pthread_mutex_init(&(this->mutex), NULL);
 150         pthread_cond_init(&(this->condvar), NULL);
 151
 152         return (&this->public);
 153 }