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