allegro/src/unix usystem.c,1.18.2.1,1.18.2.2 uthreads.c,1.7.2.2,1.7.2.3

[<ebo...@us...>]

Update of /cvsroot/alleg/allegro/src/unix
In directory sc8-pr-cvs1:/tmp/cvs-serv1001/src/unix

Modified Files:
      Tag: allegro_4_0_branch
	usystem.c uthreads.c 
Log Message:
Backported from 4.1.x:
- Sam Hocevar fixed a race condition in the mixer.
- Added synchronization routines on multi-threaded platforms.


Index: usystem.c
===================================================================
RCS file: /cvsroot/alleg/allegro/src/unix/usystem.c,v
retrieving revision 1.18.2.1
retrieving revision 1.18.2.2
diff -u -d -r1.18.2.1 -r1.18.2.2
--- usystem.c	23 Dec 2002 00:06:08 -0000	1.18.2.1
+++ usystem.c	26 Sep 2003 12:30:14 -0000	1.18.2.2
@@ -57,6 +57,26 @@
 
 
 
+/* auxilliary system driver */
+#ifdef HAVE_LIBPTHREAD
+
+SYSTEM_DRIVER_AUX unix_system_driver_aux = {
+   _unix_create_mutex,
+   _unix_destroy_mutex,
+   _unix_lock_mutex,
+   _unix_unlock_mutex
+};
+
+SYSTEM_DRIVER_AUX *_al_system_driver_aux = &unix_system_driver_aux;
+
+#else
+
+SYSTEM_DRIVER_AUX *_al_system_driver_aux = NULL;
+
+#endif
+
+
+
 /* background function manager */
 struct bg_manager *_unix_bg_man;
 

Index: uthreads.c
===================================================================
RCS file: /cvsroot/alleg/allegro/src/unix/uthreads.c,v
retrieving revision 1.7.2.2
retrieving revision 1.7.2.3
diff -u -d -r1.7.2.2 -r1.7.2.3
--- uthreads.c	22 May 2002 04:57:36 -0000	1.7.2.2
+++ uthreads.c	26 Sep 2003 12:30:14 -0000	1.7.2.3
@@ -12,6 +12,8 @@
  *
  *      By George Foot and Peter Wang.
  *
+ *      Synchronization functions added by Eric Botcazou.
+ *
  *      See readme.txt for copyright information.
  */
 
@@ -213,6 +215,86 @@
 	bg_man_pthreads_disable_interrupts,
 	bg_man_pthreads_interrupts_disabled
 };
+
+
+
+/* custom mutex that supports nested locking */
+struct my_mutex {
+   int lock_count;                /* level of nested locking     */
+   pthread_t owner;               /* thread which owns the mutex */
+   pthread_mutex_t actual_mutex;  /* underlying mutex object     */
+};
+
+
+
+/* _unix_create_mutex:
+ *  Creates a mutex and returns a pointer to it.
+ */
+void *_unix_create_mutex (void)
+{
+   struct my_mutex *mx;
+
+   mx = malloc (sizeof (struct my_mutex));
+   if (!mx) {
+      *allegro_errno = ENOMEM;
+      return NULL;
+   }
+
+   mx->lock_count = 0;
+   mx->owner = (pthread_t) 0;
+
+   pthread_mutex_init (&mx->actual_mutex, NULL);
+
+   return (void *) mx;
+}
+
+
+
+/* _unix_destroy_mutex:
+ *  Destroys a mutex.
+ */
+void _unix_destroy_mutex (void *handle)
+{
+   struct my_mutex *mx = (struct my_mutex *) handle;
+
+   pthread_mutex_destroy (&mx->actual_mutex);
+
+   free (mx);
+}
+
+
+
+/* _unix_lock_mutex:
+ *  Locks a mutex.
+ */
+void _unix_lock_mutex (void *handle)
+{
+   struct my_mutex *mx = (struct my_mutex *) handle;
+
+   if (mx->owner != pthread_self ()) {
+      pthread_mutex_lock (&mx->actual_mutex);
+      mx->owner = pthread_self ();      
+   }
+
+   mx->lock_count++;
+}
+
+
+
+/* _unix_unlock_mutex:
+ *  Unlocks a mutex.
+ */
+void _unix_unlock_mutex (void *handle)
+{
+   struct my_mutex *mx = (struct my_mutex *) handle;
+
+   mx->lock_count--;
+
+   if (mx->lock_count == 0) {
+      mx->owner = (pthread_t) 0;
+      pthread_mutex_unlock (&mx->actual_mutex);
+   }
+}
 
 #endif