cinelerra-5.1/guicast/mutex.C

   1
   2 /*
   3  * CINELERRA
   4  * Copyright (C) 2008 Adam Williams <broadcast at earthling dot net>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <errno.h>
  25
  26 #include "bcsignals.h"
  27 #include "mutex.h"
  28
  29
  30 Mutex::Mutex(const char *title, int recursive)
  31 {
  32         this->title = title;
  33         this->trace = 0;
  34         pthread_mutexattr_t attr;
  35         pthread_mutexattr_init(&attr);
  36         pthread_mutex_init(&mutex, &attr);
  37         pthread_mutex_init(&recursive_lock, &attr);
  38         count = 0;
  39         this->recursive = recursive;
  40         thread_id = 0;
  41         thread_id_valid = 0;
  42 }
  43
  44 Mutex::~Mutex()
  45 {
  46         pthread_mutex_destroy(&mutex);
  47         pthread_mutex_destroy(&recursive_lock);
  48         UNSET_ALL_LOCKS(this);
  49 }
  50
  51 int Mutex::lock(const char *location)
  52 {
  53 // Test recursive owner and give up if we already own it
  54         if(recursive)
  55         {
  56                 pthread_mutex_lock(&recursive_lock);
  57                 if(thread_id_valid && pthread_self() == thread_id)
  58                 {
  59                         count++;
  60                         pthread_mutex_unlock(&recursive_lock);
  61                         return 0;
  62                 }
  63                 pthread_mutex_unlock(&recursive_lock);
  64         }
  65
  66
  67         SET_LOCK(this, title, location);
  68         if(pthread_mutex_lock(&mutex)) perror("Mutex::lock");
  69
  70
  71
  72 // Update recursive status for the first lock
  73         if(recursive)
  74         {
  75                 pthread_mutex_lock(&recursive_lock);
  76                 count = 1;
  77                 thread_id = pthread_self();
  78                 thread_id_valid = 1;
  79                 pthread_mutex_unlock(&recursive_lock);
  80         }
  81         else
  82         {
  83                 count = 1;
  84         }
  85
  86
  87         SET_LOCK2
  88         return 0;
  89 }
  90
  91 int Mutex::unlock()
  92 {
  93         if( count <= 0 ) {
  94                 printf("Mutex::unlock not locked: %s\n", title);
  95                 return 0;
  96         }
  97 // Remove from recursive status
  98         if(recursive)
  99         {
 100                 pthread_mutex_lock(&recursive_lock);
 101                 count--;
 102 // Still locked
 103                 if(count > 0)
 104                 {
 105                         pthread_mutex_unlock(&recursive_lock);
 106                         return 0;
 107                 }
 108 // Not owned anymore
 109                 thread_id = 0;
 110                 thread_id_valid = 0;
 111                 pthread_mutex_unlock(&recursive_lock);
 112         }
 113         else
 114                 count = 0;
 115
 116
 117         UNSET_LOCK(this);
 118
 119         int ret = pthread_mutex_unlock(&mutex);
 120         if( ret ) fprintf(stderr, "Mutex::unlock: %s\n",strerror(ret));
 121         return 0;
 122 }
 123
 124 int Mutex::trylock(const char *location)
 125 {
 126         if( count ) return EBUSY;
 127         int ret = pthread_mutex_trylock(&mutex);
 128         if( ret ) return ret;
 129
 130 // Update recursive status for the first lock
 131         if(recursive) {
 132                 pthread_mutex_lock(&recursive_lock);
 133                 count = 1;
 134                 thread_id = pthread_self();
 135                 thread_id_valid = 1;
 136                 pthread_mutex_unlock(&recursive_lock);
 137         }
 138         else
 139                 count = 1;
 140
 141         SET_LOCK(this, title, location);
 142         SET_LOCK2
 143         return 0;
 144 }
 145
 146 int Mutex::is_locked()
 147 {
 148         return count;
 149 }
 150
 151 int Mutex::reset()
 152 {
 153         pthread_mutex_destroy(&mutex);
 154         pthread_mutexattr_t attr;
 155         pthread_mutexattr_init(&attr);
 156         pthread_mutex_init(&mutex, &attr);
 157         UNSET_ALL_LOCKS(this)
 158         trace = 0;
 159         count = 0;
 160         thread_id = 0;
 161         thread_id_valid = 0;
 162         return 0;
 163 }