vlc_threads.h

/*****************************************************************************
 * vlc_threads.h : threads implementation for the VideoLAN client
 * This header provides portable declarations for mutexes & conditions
 *****************************************************************************
 * Copyright (C) 1999, 2002 VLC authors and VideoLAN
 * Copyright © 2007-2008 Rémi Denis-Courmont
 *
 * Authors: Jean-Marc Dressler <polux@via.ecp.fr>
 *          Samuel Hocevar <sam@via.ecp.fr>
 *          Gildas Bazin <gbazin@netcourrier.com>
 *          Christophe Massiot <massiot@via.ecp.fr>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

#ifndef VLC_THREADS_H_
#define VLC_THREADS_H_

/**
 * \file
 * This file defines structures and functions for handling threads in vlc
 *
 */

#if defined (WIN32)
# include <process.h>
# ifndef ETIMEDOUT
#  define ETIMEDOUT 10060 /* This is the value in winsock.h. */
# endif

typedef struct vlc_thread *vlc_thread_t;
typedef struct
{
    bool dynamic;
    union
    {
        struct
        {
            bool locked;
            unsigned long contention;
        };
        CRITICAL_SECTION mutex;
    };
} vlc_mutex_t;
#define VLC_STATIC_MUTEX { false, { { false, 0 } } }
typedef struct
{
    HANDLE   handle;
    unsigned clock;
} vlc_cond_t;
#define VLC_STATIC_COND { 0, 0 }
typedef HANDLE vlc_sem_t;
#define LIBVLC_NEED_RWLOCK
typedef struct vlc_threadvar *vlc_threadvar_t;
typedef struct vlc_timer *vlc_timer_t;

# define VLC_THREAD_PRIORITY_LOW      0
# define VLC_THREAD_PRIORITY_INPUT    THREAD_PRIORITY_ABOVE_NORMAL
# define VLC_THREAD_PRIORITY_AUDIO    THREAD_PRIORITY_HIGHEST
# define VLC_THREAD_PRIORITY_VIDEO    0
# define VLC_THREAD_PRIORITY_OUTPUT   THREAD_PRIORITY_ABOVE_NORMAL
# define VLC_THREAD_PRIORITY_HIGHEST  THREAD_PRIORITY_TIME_CRITICAL

#elif defined (__OS2__)
# include <errno.h>

typedef struct vlc_thread *vlc_thread_t;
typedef struct
{
    bool dynamic;
    union
    {
        struct
        {
            bool locked;
            unsigned long contention;
        };
        HMTX hmtx;
    };
} vlc_mutex_t;
#define VLC_STATIC_MUTEX { false, { { false, 0 } } }
typedef struct
{
    HEV      hev;
    unsigned clock;
} vlc_cond_t;
#define VLC_STATIC_COND { 0, 0 }
#define LIBVLC_NEED_SEMAPHORE
#define LIBVLC_NEED_RWLOCK
typedef struct vlc_threadvar *vlc_threadvar_t;
typedef struct vlc_timer *vlc_timer_t;

# define VLC_THREAD_PRIORITY_LOW      0
# define VLC_THREAD_PRIORITY_INPUT \
                                    MAKESHORT(PRTYD_MAXIMUM / 2, PRTYC_REGULAR)
# define VLC_THREAD_PRIORITY_AUDIO    MAKESHORT(PRTYD_MAXIMUM, PRTYC_REGULAR)
# define VLC_THREAD_PRIORITY_VIDEO    0
# define VLC_THREAD_PRIORITY_OUTPUT \
                                    MAKESHORT(PRTYD_MAXIMUM / 2, PRTYC_REGULAR)
# define VLC_THREAD_PRIORITY_HIGHEST  MAKESHORT(0, PRTYC_TIMECRITICAL)

# define pthread_sigmask  sigprocmask

#elif defined (__ANDROID__)      /* pthreads subset without pthread_cancel() */
# include <unistd.h>
# include <pthread.h>
# include <poll.h>
# define LIBVLC_USE_PTHREAD_CLEANUP   1
# define LIBVLC_NEED_SEMAPHORE
# define LIBVLC_NEED_RWLOCK

typedef struct vlc_thread *vlc_thread_t;
typedef pthread_mutex_t vlc_mutex_t;
#define VLC_STATIC_MUTEX PTHREAD_MUTEX_INITIALIZER
typedef struct
{
    pthread_cond_t cond;
    unsigned clock;
} vlc_cond_t;
#define VLC_STATIC_COND  { PTHREAD_COND_INITIALIZER, CLOCK_REALTIME }

typedef pthread_key_t   vlc_threadvar_t;
typedef struct vlc_timer *vlc_timer_t;

# define VLC_THREAD_PRIORITY_LOW      0
# define VLC_THREAD_PRIORITY_INPUT    0
# define VLC_THREAD_PRIORITY_AUDIO    0
# define VLC_THREAD_PRIORITY_VIDEO    0
# define VLC_THREAD_PRIORITY_OUTPUT   0
# define VLC_THREAD_PRIORITY_HIGHEST  0

#elif defined (__APPLE__)
# define _APPLE_C_SOURCE    1 /* Proper pthread semantics on OSX */
# include <unistd.h>
# include <pthread.h>
/* Unnamed POSIX semaphores not supported on Mac OS X */
# include <mach/semaphore.h>
# include <mach/task.h>
# define LIBVLC_USE_PTHREAD           1
# define LIBVLC_USE_PTHREAD_CLEANUP   1
# define LIBVLC_USE_PTHREAD_CANCEL    1

typedef pthread_t       vlc_thread_t;
typedef pthread_mutex_t vlc_mutex_t;
#define VLC_STATIC_MUTEX PTHREAD_MUTEX_INITIALIZER
typedef pthread_cond_t  vlc_cond_t;
#define VLC_STATIC_COND  PTHREAD_COND_INITIALIZER
typedef semaphore_t     vlc_sem_t;
typedef pthread_rwlock_t vlc_rwlock_t;
#define VLC_STATIC_RWLOCK PTHREAD_RWLOCK_INITIALIZER
typedef pthread_key_t   vlc_threadvar_t;
typedef struct vlc_timer *vlc_timer_t;

# define VLC_THREAD_PRIORITY_LOW      0
# define VLC_THREAD_PRIORITY_INPUT   22
# define VLC_THREAD_PRIORITY_AUDIO   22
# define VLC_THREAD_PRIORITY_VIDEO    0
# define VLC_THREAD_PRIORITY_OUTPUT  22
# define VLC_THREAD_PRIORITY_HIGHEST 22

#else /* POSIX threads */
# include <unistd.h> /* _POSIX_SPIN_LOCKS */
# include <pthread.h>
# include <semaphore.h>
# define LIBVLC_USE_PTHREAD           1
# define LIBVLC_USE_PTHREAD_CLEANUP   1
# define LIBVLC_USE_PTHREAD_CANCEL    1

typedef pthread_t       vlc_thread_t;
typedef pthread_mutex_t vlc_mutex_t;
#define VLC_STATIC_MUTEX PTHREAD_MUTEX_INITIALIZER
typedef pthread_cond_t  vlc_cond_t;
#define VLC_STATIC_COND  PTHREAD_COND_INITIALIZER
typedef sem_t           vlc_sem_t;
typedef pthread_rwlock_t vlc_rwlock_t;
#define VLC_STATIC_RWLOCK PTHREAD_RWLOCK_INITIALIZER
typedef pthread_key_t   vlc_threadvar_t;
typedef struct vlc_timer *vlc_timer_t;

# define VLC_THREAD_PRIORITY_LOW      0
# define VLC_THREAD_PRIORITY_INPUT   10
# define VLC_THREAD_PRIORITY_AUDIO    5
# define VLC_THREAD_PRIORITY_VIDEO    0
# define VLC_THREAD_PRIORITY_OUTPUT  15
# define VLC_THREAD_PRIORITY_HIGHEST 20

#endif

#ifdef LIBVLC_NEED_SEMAPHORE
typedef struct vlc_sem
{
    vlc_mutex_t lock;
    vlc_cond_t  wait;
    unsigned    value;
} vlc_sem_t;
#endif

#ifdef LIBVLC_NEED_RWLOCK
typedef struct vlc_rwlock
{
    vlc_mutex_t   mutex;
    vlc_cond_t    wait;
    long          state;
} vlc_rwlock_t;
# define VLC_STATIC_RWLOCK { VLC_STATIC_MUTEX, VLC_STATIC_COND, 0 }
#endif

/*****************************************************************************
 * Function definitions
 *****************************************************************************/
VLC_API void vlc_mutex_init( vlc_mutex_t * );
VLC_API void vlc_mutex_init_recursive( vlc_mutex_t * );
VLC_API void vlc_mutex_destroy( vlc_mutex_t * );
VLC_API void vlc_mutex_lock( vlc_mutex_t * );
VLC_API int vlc_mutex_trylock( vlc_mutex_t * ) VLC_USED;
VLC_API void vlc_mutex_unlock( vlc_mutex_t * );
VLC_API void vlc_cond_init( vlc_cond_t * );
VLC_API void vlc_cond_init_daytime( vlc_cond_t * );
VLC_API void vlc_cond_destroy( vlc_cond_t * );
VLC_API void vlc_cond_signal(vlc_cond_t *);
VLC_API void vlc_cond_broadcast(vlc_cond_t *);
VLC_API void vlc_cond_wait(vlc_cond_t *, vlc_mutex_t *);
VLC_API int vlc_cond_timedwait(vlc_cond_t *, vlc_mutex_t *, mtime_t);
VLC_API void vlc_sem_init(vlc_sem_t *, unsigned);
VLC_API void vlc_sem_destroy(vlc_sem_t *);
VLC_API int vlc_sem_post(vlc_sem_t *);
VLC_API void vlc_sem_wait(vlc_sem_t *);

VLC_API void vlc_rwlock_init(vlc_rwlock_t *);
VLC_API void vlc_rwlock_destroy(vlc_rwlock_t *);
VLC_API void vlc_rwlock_rdlock(vlc_rwlock_t *);
VLC_API void vlc_rwlock_wrlock(vlc_rwlock_t *);
VLC_API void vlc_rwlock_unlock(vlc_rwlock_t *);
VLC_API int vlc_threadvar_create(vlc_threadvar_t * , void (*) (void *) );
VLC_API void vlc_threadvar_delete(vlc_threadvar_t *);
VLC_API int vlc_threadvar_set(vlc_threadvar_t, void *);
VLC_API void * vlc_threadvar_get(vlc_threadvar_t);

VLC_API int vlc_clone(vlc_thread_t *, void * (*) (void *), void *, int) VLC_USED;
VLC_API void vlc_cancel(vlc_thread_t);
VLC_API void vlc_join(vlc_thread_t, void **);
VLC_API void vlc_control_cancel (int cmd, ...);

VLC_API mtime_t mdate(void);
VLC_API void mwait(mtime_t deadline);
VLC_API void msleep(mtime_t delay);

#define VLC_HARD_MIN_SLEEP   10000 /* 10 milliseconds = 1 tick at 100Hz */
#define VLC_SOFT_MIN_SLEEP 9000000 /* 9 seconds */

#if VLC_GCC_VERSION(4,3)
/* Linux has 100, 250, 300 or 1000Hz
 *
 * HZ=100 by default on FreeBSD, but some architectures use a 1000Hz timer
 */

static
__attribute__((unused))
__attribute__((noinline))
__attribute__((error("sorry, cannot sleep for such short a time")))
mtime_t impossible_delay( mtime_t delay )
{
    (void) delay;
    return VLC_HARD_MIN_SLEEP;
}

static
__attribute__((unused))
__attribute__((noinline))
__attribute__((warning("use proper event handling instead of short delay")))
mtime_t harmful_delay( mtime_t delay )
{
    return delay;
}

# define check_delay( d ) \
    ((__builtin_constant_p(d < VLC_HARD_MIN_SLEEP) \
   && (d < VLC_HARD_MIN_SLEEP)) \
       ? impossible_delay(d) \
       : ((__builtin_constant_p(d < VLC_SOFT_MIN_SLEEP) \
       && (d < VLC_SOFT_MIN_SLEEP)) \
           ? harmful_delay(d) \
           : d))

static
__attribute__((unused))
__attribute__((noinline))
__attribute__((error("deadlines can not be constant")))
mtime_t impossible_deadline( mtime_t deadline )
{
    return deadline;
}

# define check_deadline( d ) \
    (__builtin_constant_p(d) ? impossible_deadline(d) : d)
#else
# define check_delay(d) (d)
# define check_deadline(d) (d)
#endif

#define msleep(d) msleep(check_delay(d))
#define mwait(d) mwait(check_deadline(d))

VLC_API int vlc_timer_create(vlc_timer_t *, void (*) (void *), void *) VLC_USED;
VLC_API void vlc_timer_destroy(vlc_timer_t);
VLC_API void vlc_timer_schedule(vlc_timer_t, bool, mtime_t, mtime_t);
VLC_API unsigned vlc_timer_getoverrun(vlc_timer_t) VLC_USED;

VLC_API unsigned vlc_GetCPUCount(void);

VLC_API int vlc_savecancel(void);
VLC_API void vlc_restorecancel(int state);
VLC_API void vlc_testcancel(void);

#if defined (LIBVLC_USE_PTHREAD_CLEANUP)
/**
 * Registers a new procedure to run if the thread is cancelled (or otherwise
 * exits prematurely). Any call to vlc_cleanup_push() <b>must</b> paired with a
 * call to either vlc_cleanup_pop() or vlc_cleanup_run(). Branching into or out
 * of the block between these two function calls is not allowed (read: it will
 * likely crash the whole process). If multiple procedures are registered,
 * they are handled in last-in first-out order.
 *
 * @param routine procedure to call if the thread ends
 * @param arg argument for the procedure
 */
# define vlc_cleanup_push( routine, arg ) pthread_cleanup_push (routine, arg)

/**
 * Removes a cleanup procedure that was previously registered with
 * vlc_cleanup_push().
 */
# define vlc_cleanup_pop( ) pthread_cleanup_pop (0)

/**
 * Removes a cleanup procedure that was previously registered with
 * vlc_cleanup_push(), and executes it.
 */
# define vlc_cleanup_run( ) pthread_cleanup_pop (1)

#else
enum
{
    VLC_CLEANUP_PUSH,
    VLC_CLEANUP_POP,
};
typedef struct vlc_cleanup_t vlc_cleanup_t;

struct vlc_cleanup_t
{
    vlc_cleanup_t *next;
    void         (*proc) (void *);
    void          *data;
};

/* This macros opens a code block on purpose. This is needed for multiple
 * calls within a single function. This also prevent Win32 developers from
 * writing code that would break on POSIX (POSIX opens a block as well). */
# define vlc_cleanup_push( routine, arg ) \
    do { \
        vlc_cleanup_t vlc_cleanup_data = { NULL, routine, arg, }; \
        vlc_control_cancel (VLC_CLEANUP_PUSH, &vlc_cleanup_data)

# define vlc_cleanup_pop( ) \
        vlc_control_cancel (VLC_CLEANUP_POP); \
    } while (0)

# define vlc_cleanup_run( ) \
        vlc_control_cancel (VLC_CLEANUP_POP); \
        vlc_cleanup_data.proc (vlc_cleanup_data.data); \
    } while (0)

#endif /* !LIBVLC_USE_PTHREAD_CLEANUO */

#ifndef LIBVLC_USE_PTHREAD_CANCEL
/* poll() with cancellation */
static inline int vlc_poll (struct pollfd *fds, unsigned nfds, int timeout)
{
    int val;

    do
    {
        int ugly_timeout = 50;
        if (timeout >= 50)
            timeout -= 50;
        else if ((unsigned)timeout < 50u)
            ugly_timeout = timeout;

        vlc_testcancel ();
        val = poll (fds, nfds, ugly_timeout);
    }
    while (val == 0 && timeout != 0);

    return val;
}
# define poll(u,n,t) vlc_poll(u, n, t)

#endif /* LIBVLC_USE_PTHREAD_CANCEL */

static inline void vlc_cleanup_lock (void *lock)
{
    vlc_mutex_unlock ((vlc_mutex_t *)lock);
}
#define mutex_cleanup_push( lock ) vlc_cleanup_push (vlc_cleanup_lock, lock)

#ifdef __cplusplus
/**
 * Helper C++ class to lock a mutex.
 * The mutex is locked when the object is created, and unlocked when the object
 * is destroyed.
 */
class vlc_mutex_locker
{
    private:
        vlc_mutex_t *lock;
    public:
        vlc_mutex_locker (vlc_mutex_t *m) : lock (m)
        {
            vlc_mutex_lock (lock);
        }

        ~vlc_mutex_locker (void)
        {
            vlc_mutex_unlock (lock);
        }
};
#endif

enum
{
   VLC_AVCODEC_MUTEX = 0,
   VLC_GCRYPT_MUTEX,
   VLC_XLIB_MUTEX,
   VLC_MOSAIC_MUTEX,
   VLC_HIGHLIGHT_MUTEX,
   VLC_ATOMIC_MUTEX,
   /* Insert new entry HERE */
   VLC_MAX_MUTEX
};

VLC_API void vlc_global_mutex( unsigned, bool );
#define vlc_global_lock( n ) vlc_global_mutex( n, true )
#define vlc_global_unlock( n ) vlc_global_mutex( n, false )

#endif /* !_VLC_THREADS_H */