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         pthread_mutexattr_t attr;
  34         pthread_mutexattr_init(&attr);
  35         pthread_mutex_init(&mutex, &attr);
  36         pthread_mutex_init(&recursive_lock, &attr);
  37         count = 0;
  38         this->recursive = recursive;
  39         thread_id = 0;
  40         thread_id_valid = 0;
  41 }
  42
  43 Mutex::~Mutex()
  44 {
  45         pthread_mutex_destroy(&mutex);
  46         pthread_mutex_destroy(&recursive_lock);
  47         UNSET_ALL_LOCKS(this);
  48 }
  49
  50 int Mutex::lock(const char *location)
  51 {
  52 // Test recursive owner and give up if we already own it
  53         if(recursive)
  54         {
  55                 pthread_mutex_lock(&recursive_lock);
  56                 if(thread_id_valid && pthread_self() == thread_id)
  57                 {
  58                         count++;
  59                         pthread_mutex_unlock(&recursive_lock);
  60                         return 0;
  61                 }
  62                 pthread_mutex_unlock(&recursive_lock);
  63         }
  64
  65
  66         SET_LOCK(this, title, location);
  67         if(pthread_mutex_lock(&mutex)) perror("Mutex::lock");
  68         set_owner();
  69
  70
  71 // Update recursive status for the first lock
  72         if(recursive)
  73         {
  74                 pthread_mutex_lock(&recursive_lock);
  75                 count = 1;
  76                 thread_id = pthread_self();
  77                 thread_id_valid = 1;
  78                 pthread_mutex_unlock(&recursive_lock);
  79         }
  80         else
  81         {
  82                 count = 1;
  83         }
  84
  85
  86         SET_LOCK2
  87         return 0;
  88 }
  89
  90 int Mutex::unlock()
  91 {
  92         if( count <= 0 ) {
  93                 printf("Mutex::unlock not locked: %s\n", title);
  94                 booby();
  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         unset_owner();
 119
 120         int ret = pthread_mutex_unlock(&mutex);
 121         if( ret ) fprintf(stderr, "Mutex::unlock: %s\n",strerror(ret));
 122         return 0;
 123 }
 124
 125 int Mutex::trylock(const char *location)
 126 {
 127         if( count ) return EBUSY;
 128         int ret = pthread_mutex_trylock(&mutex);
 129         if( ret ) return ret;
 130         set_owner();
 131
 132 // Update recursive status for the first lock
 133         if(recursive) {
 134                 pthread_mutex_lock(&recursive_lock);
 135                 count = 1;
 136                 thread_id = pthread_self();
 137                 thread_id_valid = 1;
 138                 pthread_mutex_unlock(&recursive_lock);
 139         }
 140         else
 141                 count = 1;
 142
 143         SET_LOCK(this, title, location);
 144         SET_LOCK2
 145         return 0;
 146 }
 147
 148 int Mutex::is_locked()
 149 {
 150         return count;
 151 }
 152
 153 int Mutex::reset()
 154 {
 155         pthread_mutex_destroy(&mutex);
 156         pthread_mutexattr_t attr;
 157         pthread_mutexattr_init(&attr);
 158         pthread_mutex_init(&mutex, &attr);
 159         UNSET_ALL_LOCKS(this)
 160         unset_owner();
 161         trace = 0;
 162         count = 0;
 163         thread_id = 0;
 164         thread_id_valid = 0;
 165         return 0;
 166 }