Commit 6429d700 authored by Rémi Denis-Courmont's avatar Rémi Denis-Courmont
Browse files

De-inline mutex and condition functions. Document them.

The overhead of calling a function is rather tiny compared to the
overhead of doing the system call these typically involve.

Also refs #1392
parent f8d586c2
......@@ -132,10 +132,15 @@ typedef DWORD vlc_threadvar_t;
*****************************************************************************/
VLC_EXPORT( int, vlc_mutex_init, ( vlc_mutex_t * ) );
VLC_EXPORT( int, vlc_mutex_init_recursive, ( vlc_mutex_t * ) );
VLC_EXPORT( void, __vlc_mutex_destroy, ( const char *, int, vlc_mutex_t * ) );
VLC_EXPORT( void, vlc_mutex_destroy, ( vlc_mutex_t * ) );
VLC_EXPORT( void, vlc_mutex_lock, ( vlc_mutex_t * ) );
VLC_EXPORT( void, vlc_mutex_unlock, ( vlc_mutex_t * ) );
VLC_EXPORT( int, vlc_cond_init, ( vlc_cond_t * ) );
VLC_EXPORT( void, __vlc_cond_destroy, ( const char *, int, vlc_cond_t * ) );
VLC_EXPORT( void, vlc_cond_destroy, ( vlc_cond_t * ) );
VLC_EXPORT( void, vlc_cond_signal, (vlc_cond_t *) );
VLC_EXPORT( void, vlc_cond_broadcast, (vlc_cond_t *) );
VLC_EXPORT( void, vlc_cond_wait, (vlc_cond_t *, vlc_mutex_t *) );
VLC_EXPORT( int, vlc_cond_timedwait, (vlc_cond_t *, vlc_mutex_t *, mtime_t) );
VLC_EXPORT( int, vlc_threadvar_create, (vlc_threadvar_t * , void (*) (void *) ) );
VLC_EXPORT( void, vlc_threadvar_delete, (vlc_threadvar_t *) );
VLC_EXPORT( int, __vlc_thread_create, ( vlc_object_t *, const char *, int, const char *, void * ( * ) ( vlc_object_t * ), int, bool ) );
......@@ -160,80 +165,15 @@ enum {
#define vlc_thread_ready vlc_object_signal
/*****************************************************************************
* vlc_mutex_lock: lock a mutex
*****************************************************************************/
#define vlc_mutex_lock( P_MUTEX ) \
__vlc_mutex_lock( __FILE__, __LINE__, P_MUTEX )
VLC_EXPORT(void, vlc_thread_fatal, (const char *action, int error, const char *function, const char *file, unsigned line));
#if defined(LIBVLC_USE_PTHREAD)
# define VLC_THREAD_ASSERT( action ) \
if (val) \
vlc_thread_fatal (action, val, __func__, psz_file, i_line)
#else
# define VLC_THREAD_ASSERT ((void)(val))
#endif
static inline void __vlc_mutex_lock( const char * psz_file, int i_line,
vlc_mutex_t * p_mutex )
{
#if defined(LIBVLC_USE_PTHREAD)
# define vlc_assert_locked( m ) \
assert (pthread_mutex_lock (m) == EDEADLK)
int val = pthread_mutex_lock( p_mutex );
VLC_THREAD_ASSERT ("locking mutex");
#elif defined( UNDER_CE )
(void)psz_file; (void)i_line;
EnterCriticalSection( &p_mutex->csection );
#elif defined( WIN32 )
(void)psz_file; (void)i_line;
WaitForSingleObject( *p_mutex, INFINITE );
#endif
}
#ifndef vlc_assert_locked
#else
# define vlc_assert_locked( m ) (void)m
#endif
/*****************************************************************************
* vlc_mutex_unlock: unlock a mutex
*****************************************************************************/
#define vlc_mutex_unlock( P_MUTEX ) \
__vlc_mutex_unlock( __FILE__, __LINE__, P_MUTEX )
static inline void __vlc_mutex_unlock( const char * psz_file, int i_line,
vlc_mutex_t *p_mutex )
{
#if defined(LIBVLC_USE_PTHREAD)
int val = pthread_mutex_unlock( p_mutex );
VLC_THREAD_ASSERT ("unlocking mutex");
#elif defined( UNDER_CE )
(void)psz_file; (void)i_line;
LeaveCriticalSection( &p_mutex->csection );
#elif defined( WIN32 )
(void)psz_file; (void)i_line;
ReleaseMutex( *p_mutex );
#endif
}
/*****************************************************************************
* vlc_mutex_destroy: destroy a mutex
*****************************************************************************/
#define vlc_mutex_destroy( P_MUTEX ) \
__vlc_mutex_destroy( __FILE__, __LINE__, P_MUTEX )
/**
* Save the cancellation state and disable cancellation for the calling thread.
* This function must be called before entering a piece of code that is not
......@@ -339,137 +279,6 @@ static inline void vlc_cleanup_lock (void *lock)
}
#define mutex_cleanup_push( lock ) vlc_cleanup_push (vlc_cleanup_lock, lock)
/*****************************************************************************
* vlc_cond_signal: start a thread on condition completion
*****************************************************************************/
#define vlc_cond_signal( P_COND ) \
__vlc_cond_signal( __FILE__, __LINE__, P_COND )
static inline void __vlc_cond_signal( const char * psz_file, int i_line,
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( UNDER_CE ) || defined( WIN32 )
(void)psz_file; (void)i_line;
/* Release one waiting thread if one is available. */
/* For this trick to work properly, the vlc_cond_signal must be surrounded
* by a mutex. This will prevent another thread from stealing the signal */
/* PulseEvent() only works if none of the waiting threads is suspended.
* This is particularily problematic under a debug session.
* as documented in http://support.microsoft.com/kb/q173260/ */
PulseEvent( *p_condvar );
#endif
}
/*****************************************************************************
* vlc_cond_wait: wait until condition completion
*****************************************************************************/
#define vlc_cond_wait( P_COND, P_MUTEX ) \
__vlc_cond_wait( __FILE__, __LINE__, P_COND, P_MUTEX )
static inline void __vlc_cond_wait( const char * psz_file, int i_line,
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( UNDER_CE )
LeaveCriticalSection( &p_mutex->csection );
WaitForSingleObject( *p_condvar, INFINITE );
/* Reacquire the mutex before returning. */
vlc_mutex_lock( p_mutex );
#elif defined( WIN32 )
do
vlc_testcancel ();
while (SignalObjectAndWait (*p_mutex, *p_condvar, INFINITE, TRUE)
== WAIT_IO_COMPLETION);
/* Reacquire the mutex before returning. */
vlc_mutex_lock( p_mutex );
(void)psz_file; (void)i_line;
#endif
}
/*****************************************************************************
* vlc_cond_timedwait: wait until condition completion or expiration
*****************************************************************************
* Returns 0 if object signaled, an error code in case of timeout or error.
*****************************************************************************/
#define vlc_cond_timedwait( c, m, d ) \
__vlc_cond_timedwait( __FILE__, __LINE__, c, m, check_deadline(d) )
static inline int __vlc_cond_timedwait( const char * psz_file, int i_line,
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( UNDER_CE )
mtime_t delay_ms = (deadline - mdate()) / (CLOCK_FREQ / 1000);
DWORD result;
if( delay_ms < 0 )
delay_ms = 0;
LeaveCriticalSection( &p_mutex->csection );
result = WaitForSingleObject( *p_condvar, delay_ms );
/* Reacquire the mutex before returning. */
vlc_mutex_lock( p_mutex );
(void)psz_file; (void)i_line;
return (result == WAIT_TIMEOUT) ? ETIMEDOUT : 0;
#elif defined( WIN32 )
DWORD result;
(void)psz_file; (void)i_line;
do
{
vlc_testcancel ();
mtime_t total = (deadline - mdate ())/1000;
if( total < 0 )
total = 0;
DWORD delay = (total > 0x7fffffff) ? 0x7fffffff : total;
result = SignalObjectAndWait (*p_mutex, *p_condvar, delay, TRUE);
}
while (result == WAIT_IO_COMPLETION);
/* Reacquire the mutex before return/cancel. */
vlc_mutex_lock (p_mutex);
return (result == WAIT_OBJECT_0) ? 0 : ETIMEDOUT;
#endif
}
/*****************************************************************************
* vlc_cond_destroy: destroy a condition
*****************************************************************************/
#define vlc_cond_destroy( P_COND ) \
__vlc_cond_destroy( __FILE__, __LINE__, P_COND )
/*****************************************************************************
* vlc_threadvar_set: create: set the value of a thread-local variable
*****************************************************************************/
......
......@@ -427,8 +427,11 @@ VLC_CompileDomain
VLC_CompileHost
VLC_Compiler
vlc_cond_broadcast
__vlc_cond_destroy
vlc_cond_destroy
vlc_cond_init
vlc_cond_signal
vlc_cond_timedwait
vlc_cond_wait
vlc_config_create
vlc_config_set
vlc_control_cancel
......@@ -463,9 +466,11 @@ vlc_memcpy
vlc_memset
vlc_module_create
vlc_module_set
__vlc_mutex_destroy
vlc_mutex_destroy
vlc_mutex_init
vlc_mutex_init_recursive
vlc_mutex_lock
vlc_mutex_unlock
__vlc_object_attach
__vlc_object_create
__vlc_object_detach
......
......@@ -147,6 +147,13 @@ void vlc_thread_fatal (const char *action, int error, const char *function,
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
*/
......@@ -298,28 +305,70 @@ int vlc_mutex_init_recursive( vlc_mutex_t *p_mutex )
}
/*****************************************************************************
* 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 );
DeleteCriticalSection( &p_mutex->csection );
#elif defined( WIN32 )
VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
CloseHandle( *p_mutex );
#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( UNDER_CE )
EnterCriticalSection( &p_mutex->csection );
#elif defined( WIN32 )
WaitForSingleObject( *p_mutex, INFINITE );
#endif
}
/**
* 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( UNDER_CE )
LeaveCriticalSection( &p_mutex->csection );
#elif defined( WIN32 )
ReleaseMutex( *p_mutex );
#endif
}
/*****************************************************************************
* vlc_cond_init: initialize a condition variable
*****************************************************************************/
......@@ -357,23 +406,45 @@ int vlc_cond_init( vlc_cond_t *p_condvar )
#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 );
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( UNDER_CE ) || defined( WIN32 )
/* Release one waiting thread if one is available. */
/* For this trick to work properly, the vlc_cond_signal must be surrounded
* by a mutex. This will prevent another thread from stealing the signal */
/* PulseEvent() only works if none of the waiting threads is suspended.
* This is particularily problematic under a debug session.
* as documented in http://support.microsoft.com/kb/q173260/ */
PulseEvent( *p_condvar );
#endif
}
/**
* Wakes up all threads (if any) waiting on a condition variable.
* @param p_cond condition variable
......@@ -389,6 +460,124 @@ void vlc_cond_broadcast (vlc_cond_t *p_condvar)
#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( UNDER_CE )
LeaveCriticalSection( &p_mutex->csection );
WaitForSingleObject( *p_condvar, INFINITE );
/* Reacquire the mutex before returning. */
vlc_mutex_lock( p_mutex );
#elif defined( WIN32 )
do
vlc_testcancel ();
while (SignalObjectAndWait (*p_mutex, *p_condvar, INFINITE, TRUE)
== WAIT_IO_COMPLETION);
/* Reacquire the mutex before returning. */
vlc_mutex_lock( p_mutex );
#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( UNDER_CE )
mtime_t delay_ms = (deadline - mdate()) / (CLOCK_FREQ / 1000);
DWORD result;
if( delay_ms < 0 )
delay_ms = 0;
LeaveCriticalSection( &p_mutex->csection );
result = WaitForSingleObject( *p_condvar, delay_ms );
/* Reacquire the mutex before returning. */
vlc_mutex_lock( p_mutex );
return (result == WAIT_TIMEOUT) ? ETIMEDOUT : 0;
#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;
result = SignalObjectAndWait (*p_mutex, *p_condvar, delay, TRUE);
}
while (result == WAIT_IO_COMPLETION);
/* Reacquire the mutex before return/cancel. */
vlc_mutex_lock (p_mutex);
return (result == WAIT_OBJECT_0) ? 0 : ETIMEDOUT;
#endif
}
/*****************************************************************************
* vlc_tls_create: create a thread-local variable
......
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