Source/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/allocator.h>
  29 #include <utils/linked_list.h>
  30
  31
  32 typedef struct private_job_queue_t private_job_queue_t;
  33
  34 /**
  35  * @brief Private Variables and Functions of job_queue class
  36  *
  37  */
  38 struct private_job_queue_t {
  39
  40         /**
  41          * public members
  42          */
  43         job_queue_t public;
  44
  45         /**
  46          * The jobs are stored in a linked list
  47          */
  48         linked_list_t *list;
  49
  50         /**
  51          * access to linked_list is locked through this mutex
  52          */
  53         pthread_mutex_t mutex;
  54
  55         /**
  56          * If the queue is empty a thread has to wait
  57          * This condvar is used to wake up such a thread
  58          */
  59         pthread_cond_t condvar;
  60 };
  61
  62
  63 /**
  64  * implements job_queue_t.get_count
  65  */
  66 static int get_count(private_job_queue_t *this)
  67 {
  68         int count;
  69         pthread_mutex_lock(&(this->mutex));
  70         count = this->list->get_count(this->list);
  71         pthread_mutex_unlock(&(this->mutex));
  72         return count;
  73 }
  74
  75 /**
  76  * implements job_queue_t.get
  77  */
  78 static job_t *get(private_job_queue_t *this)
  79 {
  80         int oldstate;
  81         job_t *job;
  82         pthread_mutex_lock(&(this->mutex));
  83         /* go to wait while no jobs available */
  84         while(this->list->get_count(this->list) == 0)
  85         {
  86                 /* add mutex unlock handler for cancellation, enable cancellation */
  87                 pthread_cleanup_push((void(*)(void*))pthread_mutex_unlock, (void*)&(this->mutex));
  88                 pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
  89
  90                 pthread_cond_wait( &(this->condvar), &(this->mutex));
  91
  92                 /* reset cancellation, remove mutex-unlock handler (without executing) */
  93                 pthread_setcancelstate(oldstate, NULL);
  94                 pthread_cleanup_pop(0);
  95         }
  96         this->list->remove_first(this->list,(void **) &job);
  97         pthread_mutex_unlock(&(this->mutex));
  98         return job;
  99 }
 100
 101 /**
 102  * implements function job_queue_t.add
 103  */
 104 static void add(private_job_queue_t *this, job_t *job)
 105 {
 106         pthread_mutex_lock(&(this->mutex));
 107         this->list->insert_last(this->list,job);
 108         pthread_cond_signal( &(this->condvar));
 109         pthread_mutex_unlock(&(this->mutex));
 110 }
 111
 112 /**
 113  * implements job_queue_t.destroy
 114  */
 115 static void job_queue_destroy (private_job_queue_t *this)
 116 {
 117         while (this->list->get_count(this->list) > 0)
 118         {
 119                 job_t *job;
 120                 if (this->list->remove_first(this->list,(void *) &job) != SUCCESS)
 121                 {
 122                         this->list->destroy(this->list);
 123                         break;
 124                 }
 125                 job->destroy_all(job);
 126         }
 127         this->list->destroy(this->list);
 128
 129         pthread_mutex_destroy(&(this->mutex));
 130
 131         pthread_cond_destroy(&(this->condvar));
 132
 133         allocator_free(this);
 134 }
 135
 136 /*
 137  *
 138  * Documented in header
 139  */
 140 job_queue_t *job_queue_create()
 141 {
 142         private_job_queue_t *this = allocator_alloc_thing(private_job_queue_t);
 143
 144         this->public.get_count = (int(*)(job_queue_t*))get_count;
 145         this->public.get = (job_t*(*)(job_queue_t*))get;
 146         this->public.add = (void(*)(job_queue_t*, job_t*))add;
 147         this->public.destroy = (void(*)(job_queue_t*))job_queue_destroy;
 148
 149         this->list = linked_list_create();
 150         pthread_mutex_init(&(this->mutex), NULL);
 151         pthread_cond_init(&(this->condvar), NULL);
 152
 153         return (&this->public);
 154 }