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                 return 0;
  95         }
  96 // Remove from recursive status
  97         if(recursive)
  98         {
  99                 pthread_mutex_lock(&recursive_lock);
 100                 count--;
 101 // Still locked
 102                 if(count > 0)
 103                 {
 104                         pthread_mutex_unlock(&recursive_lock);
 105                         return 0;
 106                 }
 107 // Not owned anymore
 108                 thread_id = 0;
 109                 thread_id_valid = 0;
 110                 pthread_mutex_unlock(&recursive_lock);
 111         }
 112         else
 113                 count = 0;
 114
 115
 116         UNSET_LOCK(this);
 117         unset_owner();
 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         set_owner();
 130
 131 // Update recursive status for the first lock
 132         if(recursive) {
 133                 pthread_mutex_lock(&recursive_lock);
 134                 count = 1;
 135                 thread_id = pthread_self();
 136                 thread_id_valid = 1;
 137                 pthread_mutex_unlock(&recursive_lock);
 138         }
 139         else
 140                 count = 1;
 141
 142         SET_LOCK(this, title, location);
 143         SET_LOCK2
 144         return 0;
 145 }
 146
 147 int Mutex::is_locked()
 148 {
 149         return count;
 150 }
 151
 152 int Mutex::reset()
 153 {
 154         pthread_mutex_destroy(&mutex);
 155         pthread_mutexattr_t attr;
 156         pthread_mutexattr_init(&attr);
 157         pthread_mutex_init(&mutex, &attr);
 158         UNSET_ALL_LOCKS(this)
 159         unset_owner();
 160         trace = 0;
 161         count = 0;
 162         thread_id = 0;
 163         thread_id_valid = 0;
 164         return 0;
 165 }