* Samuel Hocevar <sam@zoy.org>
* Gildas Bazin <gbazin@netcourrier.com>
* Clément Sténac
+ * Rémi Denis-Courmont
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
#endif
#include <signal.h>
-#define VLC_THREADS_UNINITIALIZED 0
-#define VLC_THREADS_PENDING 1
-#define VLC_THREADS_ERROR 2
-#define VLC_THREADS_READY 3
-
/*****************************************************************************
* Global mutex for lazy initialization of the threads system
*****************************************************************************/
static vlc_threadvar_t cancel_key;
#endif
-/**
- * Global process-wide VLC object.
- * Contains inter-instance data, such as the module cache and global mutexes.
- */
-static libvlc_global_data_t *p_root;
-
-libvlc_global_data_t *vlc_global( void )
+static struct
{
- assert( i_initializations > 0 );
- return p_root;
-}
+ vlc_dictionary_t list;
+ vlc_mutex_t lock;
+} named_mutexes;
#ifdef HAVE_EXECINFO_H
# include <execinfo.h>
*****************************************************************************
* This is mostly meant for debugging.
*****************************************************************************/
-void vlc_thread_fatal (const char *action, int error, const char *function,
- const char *file, unsigned line)
+static void
+vlc_thread_fatal (const char *action, int error,
+ const char *function, const char *file, unsigned line)
{
fprintf (stderr, "LibVLC fatal error %s (%d) in thread %lu ",
action, error, vlc_threadid ());
#ifdef __GLIBC__
/* Avoid the strerror_r() prototype brain damage in glibc */
errno = error;
- fprintf (stderr, " Error message: %m at:\n");
+ fprintf (stderr, " Error message: %m\n");
#elif !defined (WIN32)
char buf[1000];
const char *msg;
abort ();
}
+#ifndef NDEBUG
+# define VLC_THREAD_ASSERT( action ) \
+ if (val) vlc_thread_fatal (action, val, __func__, __FILE__, __LINE__)
+#else
+# define VLC_THREAD_ASSERT( action ) ((void)val)
+#endif
+
/**
* Per-thread cancellation data
*/
bool killed;
} vlc_cancel_t;
-# define VLC_CANCEL_INIT { NULL, false, true }
+# define VLC_CANCEL_INIT { NULL, true, false }
#endif
/*****************************************************************************
*****************************************************************************/
int vlc_threads_init( void )
{
- int i_ret = VLC_SUCCESS;
-
/* If we have lazy mutex initialization, use it. Otherwise, we just
* hope nothing wrong happens. */
#if defined( LIBVLC_USE_PTHREAD )
if( i_initializations == 0 )
{
- p_root = vlc_custom_create( (vlc_object_t *)NULL, sizeof( *p_root ),
- VLC_OBJECT_GENERIC, "root" );
- if( p_root == NULL )
- {
- i_ret = VLC_ENOMEM;
- goto out;
- }
-
- /* We should be safe now. Do all the initialization stuff we want. */
+ vlc_dictionary_init (&named_mutexes.list, 0);
+ vlc_mutex_init (&named_mutexes.lock);
#ifndef LIBVLC_USE_PTHREAD_CANCEL
vlc_threadvar_create( &cancel_key, free );
#endif
}
i_initializations++;
-out:
- /* If we have lazy mutex initialization support, unlock the mutex.
- * Otherwize, we are screwed. */
#if defined( LIBVLC_USE_PTHREAD )
pthread_mutex_unlock( &once_mutex );
#endif
- return i_ret;
+ return VLC_SUCCESS;
}
/*****************************************************************************
if( i_initializations == 1 )
{
- vlc_object_release( p_root );
#ifndef LIBVLC_USE_PTHREAD
vlc_threadvar_delete( &cancel_key );
#endif
+ vlc_mutex_destroy (&named_mutexes.lock);
+ vlc_dictionary_clear (&named_mutexes.list);
}
i_initializations--;
i_result = pthread_mutex_init( p_mutex, &attr );
pthread_mutexattr_destroy( &attr );
return i_result;
-#elif defined( UNDER_CE )
- InitializeCriticalSection( &p_mutex->csection );
- return 0;
#elif defined( WIN32 )
- *p_mutex = CreateMutex( 0, FALSE, 0 );
- return (*p_mutex != NULL) ? 0 : ENOMEM;
+ /* This creates a recursive mutex. This is OK as fast mutexes have
+ * no defined behavior in case of recursive locking. */
+ InitializeCriticalSection (&p_mutex->mutex);
+ return 0;
#endif
}
i_result = pthread_mutex_init( p_mutex, &attr );
pthread_mutexattr_destroy( &attr );
return( i_result );
+
#elif defined( WIN32 )
- /* Create mutex returns a recursive mutex */
- *p_mutex = CreateMutex( 0, FALSE, 0 );
- return (*p_mutex != NULL) ? 0 : ENOMEM;
-#else
-# error Unimplemented!
+ InitializeCriticalSection( &p_mutex->mutex );
+ return 0;
+
#endif
}
-/*****************************************************************************
- * vlc_mutex_destroy: destroy a mutex, inner version
- *****************************************************************************/
-void __vlc_mutex_destroy( const char * psz_file, int i_line, vlc_mutex_t *p_mutex )
+/**
+ * Destroys a mutex. The mutex must not be locked.
+ *
+ * @param p_mutex mutex to destroy
+ * @return always succeeds
+ */
+void vlc_mutex_destroy (vlc_mutex_t *p_mutex)
{
#if defined( LIBVLC_USE_PTHREAD )
int val = pthread_mutex_destroy( p_mutex );
VLC_THREAD_ASSERT ("destroying mutex");
-#elif defined( UNDER_CE )
- VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
+#elif defined( WIN32 )
+ DeleteCriticalSection (&p_mutex->mutex);
- DeleteCriticalSection( &p_mutex->csection );
+#endif
+}
+
+/**
+ * Acquires a mutex. If needed, waits for any other thread to release it.
+ * Beware of deadlocks when locking multiple mutexes at the same time,
+ * or when using mutexes from callbacks.
+ *
+ * @param p_mutex mutex initialized with vlc_mutex_init() or
+ * vlc_mutex_init_recursive()
+ */
+void vlc_mutex_lock (vlc_mutex_t *p_mutex)
+{
+#if defined(LIBVLC_USE_PTHREAD)
+ int val = pthread_mutex_lock( p_mutex );
+ VLC_THREAD_ASSERT ("locking mutex");
#elif defined( WIN32 )
- VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
+ EnterCriticalSection (&p_mutex->mutex);
+
+#endif
+}
- CloseHandle( *p_mutex );
+
+/**
+ * Releases a mutex (or crashes if the mutex is not locked by the caller).
+ * @param p_mutex mutex locked with vlc_mutex_lock().
+ */
+void vlc_mutex_unlock (vlc_mutex_t *p_mutex)
+{
+#if defined(LIBVLC_USE_PTHREAD)
+ int val = pthread_mutex_unlock( p_mutex );
+ VLC_THREAD_ASSERT ("unlocking mutex");
+
+#elif defined( WIN32 )
+ LeaveCriticalSection (&p_mutex->mutex);
#endif
}
/*****************************************************************************
- * vlc_cond_init: initialize a condition
+ * vlc_cond_init: initialize a condition variable
*****************************************************************************/
-int __vlc_cond_init( vlc_cond_t *p_condvar )
+int vlc_cond_init( vlc_cond_t *p_condvar )
{
#if defined( LIBVLC_USE_PTHREAD )
pthread_condattr_t attr;
pthread_condattr_destroy (&attr);
return ret;
-#elif defined( UNDER_CE ) || defined( WIN32 )
- /* Create an auto-reset event. */
- *p_condvar = CreateEvent( NULL, /* no security */
- FALSE, /* auto-reset event */
- FALSE, /* start non-signaled */
- NULL ); /* unnamed */
+#elif defined( WIN32 )
+ /* Create a manual-reset event (manual reset is needed for broadcast). */
+ *p_condvar = CreateEvent( NULL, TRUE, FALSE, NULL );
return *p_condvar ? 0 : ENOMEM;
#endif
}
-/*****************************************************************************
- * vlc_cond_destroy: destroy a condition, inner version
- *****************************************************************************/
-void __vlc_cond_destroy( const char * psz_file, int i_line, vlc_cond_t *p_condvar )
+/**
+ * Destroys a condition variable. No threads shall be waiting or signaling the
+ * condition.
+ * @param p_condvar condition variable to destroy
+ */
+void vlc_cond_destroy (vlc_cond_t *p_condvar)
{
#if defined( LIBVLC_USE_PTHREAD )
int val = pthread_cond_destroy( p_condvar );
VLC_THREAD_ASSERT ("destroying condition");
-#elif defined( UNDER_CE ) || defined( WIN32 )
- VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
-
+#elif defined( WIN32 )
CloseHandle( *p_condvar );
#endif
}
+/**
+ * Wakes up one thread waiting on a condition variable, if any.
+ * @param p_condvar condition variable
+ */
+void vlc_cond_signal (vlc_cond_t *p_condvar)
+{
+#if defined(LIBVLC_USE_PTHREAD)
+ int val = pthread_cond_signal( p_condvar );
+ VLC_THREAD_ASSERT ("signaling condition variable");
+
+#elif defined( WIN32 )
+ /* NOTE: This will cause a broadcast, that is wrong.
+ * This will also wake up the next waiting thread if no thread are yet
+ * waiting, which is also wrong. However both of these issues are allowed
+ * by the provision for spurious wakeups. Better have too many wakeups
+ * than too few (= deadlocks). */
+ SetEvent (*p_condvar);
+
+#endif
+}
+
+/**
+ * Wakes up all threads (if any) waiting on a condition variable.
+ * @param p_cond condition variable
+ */
+void vlc_cond_broadcast (vlc_cond_t *p_condvar)
+{
+#if defined (LIBVLC_USE_PTHREAD)
+ pthread_cond_broadcast (p_condvar);
+
+#elif defined (WIN32)
+ SetEvent (*p_condvar);
+
+#endif
+}
+
+#ifdef UNDER_CE
+# warning FIXME
+# define WaitForMultipleObjectsEx(a,b,c) WaitForMultipleObjects(a,b)
+#endif
+
+/**
+ * Waits for a condition variable. The calling thread will be suspended until
+ * another thread calls vlc_cond_signal() or vlc_cond_broadcast() on the same
+ * condition variable, the thread is cancelled with vlc_cancel(), or the
+ * system causes a "spurious" unsolicited wake-up.
+ *
+ * A mutex is needed to wait on a condition variable. It must <b>not</b> be
+ * a recursive mutex. Although it is possible to use the same mutex for
+ * multiple condition, it is not valid to use different mutexes for the same
+ * condition variable at the same time from different threads.
+ *
+ * In case of thread cancellation, the mutex is always locked before
+ * cancellation proceeds.
+ *
+ * The canonical way to use a condition variable to wait for event foobar is:
+ @code
+ vlc_mutex_lock (&lock);
+ mutex_cleanup_push (&lock); // release the mutex in case of cancellation
+
+ while (!foobar)
+ vlc_cond_wait (&wait, &lock);
+
+ --- foobar is now true, do something about it here --
+
+ vlc_cleanup_run (); // release the mutex
+ @endcode
+ *
+ * @param p_condvar condition variable to wait on
+ * @param p_mutex mutex which is unlocked while waiting,
+ * then locked again when waking up.
+ * @param deadline <b>absolute</b> timeout
+ *
+ * @return 0 if the condition was signaled, an error code in case of timeout.
+ */
+void vlc_cond_wait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex)
+{
+#if defined(LIBVLC_USE_PTHREAD)
+ int val = pthread_cond_wait( p_condvar, p_mutex );
+ VLC_THREAD_ASSERT ("waiting on condition");
+
+#elif defined( WIN32 )
+ DWORD result;
+
+ do
+ {
+ vlc_testcancel ();
+ LeaveCriticalSection (&p_mutex->mutex);
+ result = WaitForSingleObjectEx (*p_condvar, INFINITE, TRUE);
+ EnterCriticalSection (&p_mutex->mutex);
+ }
+ while (result == WAIT_IO_COMPLETION);
+
+ ResetEvent (*p_condvar);
+
+#endif
+}
+
+/**
+ * Waits for a condition variable up to a certain date.
+ * This works like vlc_cond_wait(), except for the additional timeout.
+ *
+ * @param p_condvar condition variable to wait on
+ * @param p_mutex mutex which is unlocked while waiting,
+ * then locked again when waking up.
+ * @param deadline <b>absolute</b> timeout
+ *
+ * @return 0 if the condition was signaled, an error code in case of timeout.
+ */
+int vlc_cond_timedwait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex,
+ mtime_t deadline)
+{
+#if defined(LIBVLC_USE_PTHREAD)
+ lldiv_t d = lldiv( deadline, CLOCK_FREQ );
+ struct timespec ts = { d.quot, d.rem * (1000000000 / CLOCK_FREQ) };
+
+ int val = pthread_cond_timedwait (p_condvar, p_mutex, &ts);
+ if (val != ETIMEDOUT)
+ VLC_THREAD_ASSERT ("timed-waiting on condition");
+ return val;
+
+#elif defined( WIN32 )
+ DWORD result;
+
+ do
+ {
+ vlc_testcancel ();
+
+ mtime_t total = (deadline - mdate ())/1000;
+ if( total < 0 )
+ total = 0;
+
+ DWORD delay = (total > 0x7fffffff) ? 0x7fffffff : total;
+ LeaveCriticalSection (&p_mutex->mutex);
+ result = WaitForSingleObjectEx (*p_condvar, delay, TRUE);
+ EnterCriticalSection (&p_mutex->mutex);
+ }
+ while (result == WAIT_IO_COMPLETION);
+
+ ResetEvent (*p_condvar);
+
+ return (result == WAIT_OBJECT_0) ? 0 : ETIMEDOUT;
+
+#endif
+}
+
/*****************************************************************************
* vlc_tls_create: create a thread-local variable
*****************************************************************************/
pthread_attr_setschedparam (&attr, &sp);
}
+ /* The thread stack size.
+ * The lower the value, the less address space per thread, the highest
+ * maximum simultaneous threads per process. Too low values will cause
+ * stack overflows and weird crashes. Set with caution. Also keep in mind
+ * that 64-bits platforms consume more stack than 32-bits one.
+ *
+ * Thanks to on-demand paging, thread stack size only affects address space
+ * consumption. In terms of memory, threads only use what they need
+ * (rounded up to the page boundary).
+ *
+ * For example, on Linux i386, the default is 2 mega-bytes, which supports
+ * about 320 threads per processes. */
+#define VLC_STACKSIZE (128 * sizeof (void *) * 1024)
+
+#ifdef VLC_STACKSIZE
+ ret = pthread_attr_setstacksize (&attr, VLC_STACKSIZE);
+ assert (ret == 0); /* fails iif VLC_STACKSIZE is invalid */
+#endif
+
ret = pthread_create (p_handle, &attr, entry, data);
pthread_sigmask (SIG_SETMASK, &oldset, NULL);
pthread_attr_destroy (&attr);
boot->entry = func;
boot->object = p_this;
- vlc_object_lock( p_this );
-
/* Make sure we don't re-create a thread if the object has already one */
assert( !p_priv->b_thread );
#if defined( LIBVLC_USE_PTHREAD )
+ if (b_wait)
+ sem_init (&p_priv->thread_ready, 0, 0);
#ifndef __APPLE__
if( config_GetInt( p_this, "rt-priority" ) > 0 )
#endif
if( config_GetType( p_this, "rt-offset" ) )
i_priority += config_GetInt( p_this, "rt-offset" );
}
+#elif defined (WIN32)
+ if (b_wait)
+ p_priv->thread_ready = CreateEvent (NULL, TRUE, FALSE, NULL);
#endif
+ p_priv->b_thread = true;
i_ret = vlc_clone( &p_priv->thread_id, thread_entry, boot, i_priority );
if( i_ret == 0 )
{
+ msg_Dbg( p_this, "thread %lu (%s) created at priority %d (%s:%d)",
+ (unsigned long)p_priv->thread_id, psz_name, i_priority,
+ psz_file, i_line );
if( b_wait )
{
msg_Dbg( p_this, "waiting for thread initialization" );
- vlc_object_wait( p_this );
+#if defined (LIBVLC_USE_PTHREAD)
+ sem_wait (&p_priv->thread_ready);
+ sem_destroy (&p_priv->thread_ready);
+#elif defined (WIN32)
+ WaitForSingleObject (p_priv->thread_ready, INFINITE);
+ CloseHandle (p_priv->thread_ready);
+#endif
}
-
- p_priv->b_thread = true;
- msg_Dbg( p_this, "thread %lu (%s) created at priority %d (%s:%d)",
- (unsigned long)p_priv->thread_id, psz_name, i_priority,
- psz_file, i_line );
}
else
{
+ p_priv->b_thread = false;
errno = i_ret;
msg_Err( p_this, "%s thread could not be created at %s:%d (%m)",
psz_name, psz_file, i_line );
}
- vlc_object_unlock( p_this );
return i_ret;
}
+#undef vlc_thread_ready
+void vlc_thread_ready (vlc_object_t *obj)
+{
+ vlc_object_internals_t *priv = vlc_internals (obj);
+
+ assert (priv->b_thread);
+#if defined (LIBVLC_USE_PTHREAD)
+ assert (pthread_equal (pthread_self (), priv->thread_id));
+ sem_post (&priv->thread_ready);
+#elif defined (WIN32)
+ SetEvent (priv->thread_ready);
+#endif
+}
+
/*****************************************************************************
* vlc_thread_set_priority: set the priority of the current thread when we
* couldn't set it in vlc_thread_create (for instance for the main thread)
#else
va_list ap;
- va_start (ap, cmd);
-
vlc_cancel_t *nfo = vlc_threadvar_get (&cancel_key);
if (nfo == NULL)
{
#endif
}
+ va_start (ap, cmd);
switch (cmd)
{
case VLC_SAVE_CANCEL:
{
for (vlc_cleanup_t *p = nfo->cleaners; p != NULL; p = p->next)
p->proc (p->data);
+#ifndef WIN32
free (nfo);
+#endif
#if defined (LIBVLC_USE_PTHREAD)
pthread_exit (PTHREAD_CANCELLED);
+#elif defined (UNDER_CE)
+ ExitThread(0);
#elif defined (WIN32)
_endthread ();
#else
va_end (ap);
#endif
}
+
+
+#undef var_AcquireMutex
+/**
+ * Finds a process-wide mutex, creates it if needed, and locks it.
+ * Unlock with vlc_mutex_unlock().
+ * FIXME: This is very inefficient, this is not memory-safe and this leaks
+ * memory. Use static locks instead.
+ */
+vlc_mutex_t *var_AcquireMutex( const char *name )
+{
+ vlc_mutex_t *lock;
+
+ vlc_mutex_lock (&named_mutexes.lock);
+ lock = vlc_dictionary_value_for_key (&named_mutexes.list, name);
+ if (lock == kVLCDictionaryNotFound)
+ {
+ lock = malloc (sizeof (*lock));
+ vlc_mutex_init (lock);
+ vlc_dictionary_insert (&named_mutexes.list, name, lock);
+ }
+ vlc_mutex_unlock (&named_mutexes.lock);
+
+ vlc_mutex_lock (lock);
+ return lock;
+}
projects / vlc / blobdiff