vlc_threads_funcs.h

/*****************************************************************************
 * vlc_threads_funcs.h : threads implementation for the VideoLAN client
 * This header provides a portable threads implementation.
 *****************************************************************************
 * Copyright (C) 1999, 2002 the VideoLAN team
 * $Id: vlc_threads_funcs.h 11664 2005-07-09 06:17:09Z courmisch $
 *
 * Authors: Jean-Marc Dressler <[email protected]>
 *          Samuel Hocevar <[email protected]>
 *          Gildas Bazin <[email protected]>
 *          Christophe Massiot <[email protected]>
 *
 * 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
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/

/*****************************************************************************
 * Function definitions
 *****************************************************************************/
VLC_EXPORT( int,  __vlc_threads_init,  ( vlc_object_t * ) );
VLC_EXPORT( int,  __vlc_threads_end,   ( vlc_object_t * ) );
VLC_EXPORT( int,  __vlc_mutex_init,    ( vlc_object_t *, vlc_mutex_t * ) );
VLC_EXPORT( int,  __vlc_mutex_destroy, ( char *, int, vlc_mutex_t * ) );
VLC_EXPORT( int,  __vlc_cond_init,     ( vlc_object_t *, vlc_cond_t * ) );
VLC_EXPORT( int,  __vlc_cond_destroy,  ( char *, int, vlc_cond_t * ) );
VLC_EXPORT( int,  __vlc_thread_create, ( vlc_object_t *, char *, int, char *, void * ( * ) ( void * ), int, vlc_bool_t ) );
VLC_EXPORT( int,  __vlc_thread_set_priority, ( vlc_object_t *, char *, int, int ) );
VLC_EXPORT( void, __vlc_thread_ready,  ( vlc_object_t * ) );
VLC_EXPORT( void, __vlc_thread_join,   ( vlc_object_t *, char *, int ) );


/*****************************************************************************
 * vlc_threads_init: initialize threads system
 *****************************************************************************/
#define vlc_threads_init( P_THIS )                                          \
    __vlc_threads_init( VLC_OBJECT(P_THIS) )

/*****************************************************************************
 * vlc_threads_end: deinitialize threads system
 *****************************************************************************/
#define vlc_threads_end( P_THIS )                                           \
    __vlc_threads_end( VLC_OBJECT(P_THIS) )

/*****************************************************************************
 * vlc_mutex_init: initialize a mutex
 *****************************************************************************/
#define vlc_mutex_init( P_THIS, P_MUTEX )                                   \
    __vlc_mutex_init( VLC_OBJECT(P_THIS), P_MUTEX )

/*****************************************************************************
 * vlc_mutex_lock: lock a mutex
 *****************************************************************************/
#define vlc_mutex_lock( P_MUTEX )                                           \
    __vlc_mutex_lock( __FILE__, __LINE__, P_MUTEX )

static inline int __vlc_mutex_lock( char * psz_file, int i_line,
                                    vlc_mutex_t * p_mutex )
{
    int i_result;
    /* In case of error : */
    int i_thread = -1;
    const char * psz_error = "";

#if defined( PTH_INIT_IN_PTH_H )
    i_result = ( pth_mutex_acquire( &p_mutex->mutex, FALSE, NULL ) == FALSE );

#elif defined( ST_INIT_IN_ST_H )
    i_result = st_mutex_lock( p_mutex->mutex );

#elif defined( UNDER_CE )
    EnterCriticalSection( &p_mutex->csection );
    i_result = 0;

#elif defined( WIN32 )
    if( p_mutex->mutex )
    {
        WaitForSingleObject( p_mutex->mutex, INFINITE );
    }
    else
    {
        EnterCriticalSection( &p_mutex->csection );
    }
    i_result = 0;

#elif defined( HAVE_KERNEL_SCHEDULER_H )
    if( p_mutex == NULL )
    {
        i_result = B_BAD_VALUE;
    }
    else if( p_mutex->init < 2000 )
    {
        i_result = B_NO_INIT;
    }
    else
    {
        i_result = acquire_sem( p_mutex->lock );
    }

#elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
    i_result = pthread_mutex_lock( &p_mutex->mutex );
    if ( i_result )
    {
        i_thread = (int)pthread_self();
        psz_error = strerror(i_result);
    }

#elif defined( HAVE_CTHREADS_H )
    mutex_lock( p_mutex->mutex );
    i_result = 0;

#endif

    if( i_result )
    {
        msg_Err( p_mutex->p_this,
                 "thread %u: mutex_lock failed at %s:%d (%d:%s)",
                 i_thread, psz_file, i_line, i_result, psz_error );
    }
    return i_result;
}

/*****************************************************************************
 * vlc_mutex_unlock: unlock a mutex
 *****************************************************************************/
#define vlc_mutex_unlock( P_MUTEX )                                         \
    __vlc_mutex_unlock( __FILE__, __LINE__, P_MUTEX )

static inline int __vlc_mutex_unlock( char * psz_file, int i_line,
                                      vlc_mutex_t *p_mutex )
{
    int i_result;
    /* In case of error : */
    int i_thread = -1;
    const char * psz_error = "";

#if defined( PTH_INIT_IN_PTH_H )
    i_result = ( pth_mutex_release( &p_mutex->mutex ) == FALSE );

#elif defined( ST_INIT_IN_ST_H )
    i_result = st_mutex_unlock( p_mutex->mutex );

#elif defined( UNDER_CE )
    LeaveCriticalSection( &p_mutex->csection );
    i_result = 0;

#elif defined( WIN32 )
    if( p_mutex->mutex )
    {
        ReleaseMutex( p_mutex->mutex );
    }
    else
    {
        LeaveCriticalSection( &p_mutex->csection );
    }
    i_result = 0;

#elif defined( HAVE_KERNEL_SCHEDULER_H )
    if( p_mutex == NULL )
    {
        i_result = B_BAD_VALUE;
    }
    else if( p_mutex->init < 2000 )
    {
        i_result = B_NO_INIT;
    }
    else
    {
        release_sem( p_mutex->lock );
        return B_OK;
    }

#elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
    i_result = pthread_mutex_unlock( &p_mutex->mutex );
    if ( i_result )
    {
        i_thread = (int)pthread_self();
        psz_error = strerror(i_result);
    }

#elif defined( HAVE_CTHREADS_H )
    mutex_unlock( p_mutex );
    i_result = 0;

#endif

    if( i_result )
    {
        msg_Err( p_mutex->p_this,
                 "thread %u: mutex_unlock failed at %s:%d (%d:%s)",
                 i_thread, psz_file, i_line, i_result, psz_error );
    }

    return i_result;
}

/*****************************************************************************
 * vlc_mutex_destroy: destroy a mutex
 *****************************************************************************/
#define vlc_mutex_destroy( P_MUTEX )                                        \
    __vlc_mutex_destroy( __FILE__, __LINE__, P_MUTEX )

/*****************************************************************************
 * vlc_cond_init: initialize a condition
 *****************************************************************************/
#define vlc_cond_init( P_THIS, P_COND )                                     \
    __vlc_cond_init( VLC_OBJECT(P_THIS), P_COND )

/*****************************************************************************
 * vlc_cond_signal: start a thread on condition completion
 *****************************************************************************/
#define vlc_cond_signal( P_COND )                                           \
    __vlc_cond_signal( __FILE__, __LINE__, P_COND )

static inline int __vlc_cond_signal( char * psz_file, int i_line,
                                     vlc_cond_t *p_condvar )
{
    int i_result;
    /* In case of error : */
    int i_thread = -1;
    const char * psz_error = "";

#if defined( PTH_INIT_IN_PTH_H )
    i_result = ( pth_cond_notify( &p_condvar->cond, FALSE ) == FALSE );

#elif defined( ST_INIT_IN_ST_H )
    i_result = st_cond_signal( p_condvar->cond );

#elif defined( UNDER_CE )
    PulseEvent( p_condvar->event );
    i_result = 0;

#elif 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 */
    if( !p_condvar->semaphore )
    {
        PulseEvent( p_condvar->event );
    }
    else if( p_condvar->i_win9x_cv == 1 )
    {
        /* Wait for the gate to be open */
        WaitForSingleObject( p_condvar->event, INFINITE );

        if( p_condvar->i_waiting_threads )
        {
            /* Using a semaphore exposes us to a race condition. It is
             * possible for another thread to start waiting on the semaphore
             * just after we signaled it and thus steal the signal.
             * We have to prevent new threads from entering the cond_wait(). */
            ResetEvent( p_condvar->event );

            /* A semaphore is used here because Win9x doesn't have
             * SignalObjectAndWait() and thus a race condition exists
             * during the time we release the mutex and the time we start
             * waiting on the event (more precisely, the signal can sometimes
             * be missed by the waiting thread if we use PulseEvent()). */
            ReleaseSemaphore( p_condvar->semaphore, 1, 0 );
        }
    }
    else
    {
        if( p_condvar->i_waiting_threads )
        {
            ReleaseSemaphore( p_condvar->semaphore, 1, 0 );

            /* Wait for the last thread to be awakened */
            WaitForSingleObject( p_condvar->event, INFINITE );
        }
    }
    i_result = 0;

#elif defined( HAVE_KERNEL_SCHEDULER_H )
    if( p_condvar == NULL )
    {
        i_result = B_BAD_VALUE;
    }
    else if( p_condvar->init < 2000 )
    {
        i_result = B_NO_INIT;
    }
    else
    {
        while( p_condvar->thread != -1 )
        {
            thread_info info;
            if( get_thread_info(p_condvar->thread, &info) == B_BAD_VALUE )
            {
                return 0;
            }

            if( info.state != B_THREAD_SUSPENDED )
            {
                /* The  waiting thread is not suspended so it could
                 * have been interrupted beetwen the unlock and the
                 * suspend_thread line. That is why we sleep a little
                 * before retesting p_condver->thread. */
                snooze( 10000 );
            }
            else
            {
                /* Ok, we have to wake up that thread */
                resume_thread( p_condvar->thread );
                return 0;
            }
        }
        i_result = 0;
    }

#elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
    i_result = pthread_cond_signal( &p_condvar->cond );
    if ( i_result )
    {
        i_thread = (int)pthread_self();
        psz_error = strerror(i_result);
    }

#elif defined( HAVE_CTHREADS_H )
    /* condition_signal() */
    if ( p_condvar->queue.head || p_condvar->implications )
    {
        cond_signal( (condition_t)p_condvar );
    }
    i_result = 0;

#endif

    if( i_result )
    {
        msg_Err( p_condvar->p_this,
                 "thread %u: cond_signal failed at %s:%d (%d:%s)",
                 i_thread, psz_file, i_line, i_result, psz_error );
    }

    return i_result;
}

/*****************************************************************************
 * 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 int __vlc_cond_wait( char * psz_file, int i_line,
                                   vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex )
{
    int i_result;
    /* In case of error : */
    int i_thread = -1;
    const char * psz_error = "";

#if defined( PTH_INIT_IN_PTH_H )
    i_result = ( pth_cond_await( &p_condvar->cond, &p_mutex->mutex, NULL )
                 == FALSE );

#elif defined( ST_INIT_IN_ST_H )
    st_mutex_unlock( p_mutex->mutex );
    i_result = st_cond_wait( p_condvar->cond );
    st_mutex_lock( p_mutex->mutex );

#elif defined( UNDER_CE )
    p_condvar->i_waiting_threads++;
    LeaveCriticalSection( &p_mutex->csection );
    WaitForSingleObject( p_condvar->event, INFINITE );
    p_condvar->i_waiting_threads--;

    /* Reacquire the mutex before returning. */
    vlc_mutex_lock( p_mutex );

    i_result = 0;

#elif defined( WIN32 )
    if( !p_condvar->semaphore )
    {
        /* Increase our wait count */
        p_condvar->i_waiting_threads++;

        if( p_mutex->mutex )
        {
            /* It is only possible to atomically release the mutex and
             * initiate the waiting on WinNT/2K/XP. Win9x doesn't have
             * SignalObjectAndWait(). */
            p_condvar->SignalObjectAndWait( p_mutex->mutex,
                                            p_condvar->event,
                                            INFINITE, FALSE );
        }
        else
        {
            LeaveCriticalSection( &p_mutex->csection );
            WaitForSingleObject( p_condvar->event, INFINITE );
        }

        p_condvar->i_waiting_threads--;
    }
    else if( p_condvar->i_win9x_cv == 1 )
    {
        int i_waiting_threads;

        /* Wait for the gate to be open */
        WaitForSingleObject( p_condvar->event, INFINITE );

        /* Increase our wait count */
        p_condvar->i_waiting_threads++;

        LeaveCriticalSection( &p_mutex->csection );
        WaitForSingleObject( p_condvar->semaphore, INFINITE );

        /* Decrement and test must be atomic */
        EnterCriticalSection( &p_condvar->csection );

        /* Decrease our wait count */
        i_waiting_threads = --p_condvar->i_waiting_threads;

        LeaveCriticalSection( &p_condvar->csection );

        /* Reopen the gate if we were the last waiting thread */
        if( !i_waiting_threads )
            SetEvent( p_condvar->event );
    }
    else
    {
        int i_waiting_threads;

        /* Increase our wait count */
        p_condvar->i_waiting_threads++;

        LeaveCriticalSection( &p_mutex->csection );
        WaitForSingleObject( p_condvar->semaphore, INFINITE );

        /* Decrement and test must be atomic */
        EnterCriticalSection( &p_condvar->csection );

        /* Decrease our wait count */
        i_waiting_threads = --p_condvar->i_waiting_threads;

        LeaveCriticalSection( &p_condvar->csection );

        /* Signal that the last waiting thread just went through */
        if( !i_waiting_threads )
            SetEvent( p_condvar->event );
    }

    /* Reacquire the mutex before returning. */
    vlc_mutex_lock( p_mutex );

    i_result = 0;

#elif defined( HAVE_KERNEL_SCHEDULER_H )
    if( p_condvar == NULL )
    {
        i_result = B_BAD_VALUE;
    }
    else if( p_mutex == NULL )
    {
        i_result = B_BAD_VALUE;
    }
    else if( p_condvar->init < 2000 )
    {
        i_result = B_NO_INIT;
    }

    /* The p_condvar->thread var is initialized before the unlock because
     * it enables to identify when the thread is interrupted beetwen the
     * unlock line and the suspend_thread line */
    p_condvar->thread = find_thread( NULL );
    vlc_mutex_unlock( p_mutex );
    suspend_thread( p_condvar->thread );
    p_condvar->thread = -1;

    vlc_mutex_lock( p_mutex );
    i_result = 0;

#elif defined( PTHREAD_COND_T_IN_PTHREAD_H )

#   ifdef DEBUG
    /* In debug mode, timeout */
    struct timeval now;
    struct timespec timeout;

    gettimeofday( &now, NULL );
    timeout.tv_sec = now.tv_sec + THREAD_COND_TIMEOUT;
    timeout.tv_nsec = now.tv_usec * 1000;

    i_result = pthread_cond_timedwait( &p_condvar->cond, &p_mutex->mutex,
                                       &timeout );

    if( i_result == ETIMEDOUT )
    {
        /* People keep pissing me off with this. --Meuuh */
        msg_Dbg( p_condvar->p_this,
                  "thread %u: secret message triggered "
                  "at %s:%d (%s)", (int)pthread_self(),
                  psz_file, i_line, strerror(i_result) );

        i_result = pthread_cond_wait( &p_condvar->cond, &p_mutex->mutex );
    }

#   else
    i_result = pthread_cond_wait( &p_condvar->cond, &p_mutex->mutex );
#   endif

    if ( i_result )
    {
        i_thread = (int)pthread_self();
        psz_error = strerror(i_result);
    }

#elif defined( HAVE_CTHREADS_H )
    condition_wait( (condition_t)p_condvar, (mutex_t)p_mutex );
    i_result = 0;

#endif

    if( i_result )
    {
        msg_Err( p_condvar->p_this,
                 "thread %u: cond_wait failed at %s:%d (%d:%s)",
                 i_thread, psz_file, i_line, i_result, psz_error );
    }

    return i_result;
}

/*****************************************************************************
 * vlc_cond_destroy: destroy a condition
 *****************************************************************************/
#define vlc_cond_destroy( P_COND )                                          \
    __vlc_cond_destroy( __FILE__, __LINE__, P_COND )

/*****************************************************************************
 * vlc_thread_create: create a thread
 *****************************************************************************/
#define vlc_thread_create( P_THIS, PSZ_NAME, FUNC, PRIORITY, WAIT )         \
    __vlc_thread_create( VLC_OBJECT(P_THIS), __FILE__, __LINE__, PSZ_NAME, (void * ( * ) ( void * ))FUNC, PRIORITY, WAIT )

/*****************************************************************************
 * vlc_thread_set_priority: set the priority of the calling thread
 *****************************************************************************/
#define vlc_thread_set_priority( P_THIS, PRIORITY )                         \
    __vlc_thread_set_priority( VLC_OBJECT(P_THIS), __FILE__, __LINE__, PRIORITY )

/*****************************************************************************
 * vlc_thread_ready: tell the parent thread we were successfully spawned
 *****************************************************************************/
#define vlc_thread_ready( P_THIS )                                          \
    __vlc_thread_ready( VLC_OBJECT(P_THIS) )

/*****************************************************************************
 * vlc_thread_join: wait until a thread exits
 *****************************************************************************/
#define vlc_thread_join( P_THIS )                                           \
    __vlc_thread_join( VLC_OBJECT(P_THIS), __FILE__, __LINE__ )

---