include/vlc_threads.h

   1 /*****************************************************************************
   2  * vlc_threads.h : threads implementation for the VideoLAN client
   3  * This header provides portable declarations for mutexes & conditions
   4  *****************************************************************************
   5  * Copyright (C) 1999, 2002 the VideoLAN team
   6  * Copyright © 2007-2008 Rémi Denis-Courmont
   7  *
   8  * Authors: Jean-Marc Dressler <polux@via.ecp.fr>
   9  *          Samuel Hocevar <sam@via.ecp.fr>
  10  *          Gildas Bazin <gbazin@netcourrier.com>
  11  *          Christophe Massiot <massiot@via.ecp.fr>
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  26  *****************************************************************************/
  27
  28 #ifndef VLC_THREADS_H_
  29 #define VLC_THREADS_H_
  30
  31 /**
  32  * \file
  33  * This file defines structures and functions for handling threads in vlc
  34  *
  35  */
  36
  37 #if defined( UNDER_CE )
  38 #elif defined( WIN32 )
  39 #   include <process.h>                                         /* Win32 API */
  40
  41 #else                                         /* pthreads (like Linux & BSD) */
  42 #   define LIBVLC_USE_PTHREAD 1
  43 #   define LIBVLC_USE_PTHREAD_CANCEL 1
  44 #   define _APPLE_C_SOURCE    1 /* Proper pthread semantics on OSX */
  45
  46 #   include <unistd.h> /* _POSIX_SPIN_LOCKS */
  47 #   include <pthread.h>
  48 #   include <semaphore.h>
  49
  50 #endif
  51
  52 /*****************************************************************************
  53  * Constants
  54  *****************************************************************************/
  55
  56 /* Thread priorities */
  57 #ifdef __APPLE__
  58 #   define VLC_THREAD_PRIORITY_LOW      0
  59 #   define VLC_THREAD_PRIORITY_INPUT   22
  60 #   define VLC_THREAD_PRIORITY_AUDIO   22
  61 #   define VLC_THREAD_PRIORITY_VIDEO    0
  62 #   define VLC_THREAD_PRIORITY_OUTPUT  22
  63 #   define VLC_THREAD_PRIORITY_HIGHEST 22
  64
  65 #elif defined(LIBVLC_USE_PTHREAD)
  66 #   define VLC_THREAD_PRIORITY_LOW      0
  67 #   define VLC_THREAD_PRIORITY_INPUT   10
  68 #   define VLC_THREAD_PRIORITY_AUDIO    5
  69 #   define VLC_THREAD_PRIORITY_VIDEO    0
  70 #   define VLC_THREAD_PRIORITY_OUTPUT  15
  71 #   define VLC_THREAD_PRIORITY_HIGHEST 20
  72
  73 #elif defined(WIN32) || defined(UNDER_CE)
  74 /* Define different priorities for WinNT/2K/XP and Win9x/Me */
  75 #   define VLC_THREAD_PRIORITY_LOW 0
  76 #   define VLC_THREAD_PRIORITY_INPUT \
  77         THREAD_PRIORITY_ABOVE_NORMAL
  78 #   define VLC_THREAD_PRIORITY_AUDIO \
  79         THREAD_PRIORITY_HIGHEST
  80 #   define VLC_THREAD_PRIORITY_VIDEO 0
  81 #   define VLC_THREAD_PRIORITY_OUTPUT \
  82         THREAD_PRIORITY_ABOVE_NORMAL
  83 #   define VLC_THREAD_PRIORITY_HIGHEST \
  84         THREAD_PRIORITY_TIME_CRITICAL
  85
  86 #else
  87 #   define VLC_THREAD_PRIORITY_LOW 0
  88 #   define VLC_THREAD_PRIORITY_INPUT 0
  89 #   define VLC_THREAD_PRIORITY_AUDIO 0
  90 #   define VLC_THREAD_PRIORITY_VIDEO 0
  91 #   define VLC_THREAD_PRIORITY_OUTPUT 0
  92 #   define VLC_THREAD_PRIORITY_HIGHEST 0
  93
  94 #endif
  95
  96 /*****************************************************************************
  97  * Type definitions
  98  *****************************************************************************/
  99
 100 #if defined (LIBVLC_USE_PTHREAD)
 101 typedef pthread_t       vlc_thread_t;
 102 typedef pthread_mutex_t vlc_mutex_t;
 103 #define VLC_STATIC_MUTEX PTHREAD_MUTEX_INITIALIZER
 104 typedef pthread_cond_t  vlc_cond_t;
 105 #define VLC_STATIC_COND  PTHREAD_COND_INITIALIZER
 106 typedef sem_t           vlc_sem_t;
 107 typedef pthread_rwlock_t vlc_rwlock_t;
 108 typedef pthread_key_t   vlc_threadvar_t;
 109 typedef struct vlc_timer *vlc_timer_t;
 110
 111 #elif defined( WIN32 )
 112 #if !defined( UNDER_CE )
 113 typedef HANDLE vlc_thread_t;
 114 #else
 115 typedef struct
 116 {
 117     HANDLE handle;
 118     HANDLE cancel_event;
 119 } *vlc_thread_t;
 120 #endif
 121
 122 typedef struct
 123 {
 124     bool dynamic;
 125     union
 126     {
 127         struct
 128         {
 129             bool locked;
 130             unsigned long contention;
 131         };
 132         CRITICAL_SECTION mutex;
 133     };
 134 } vlc_mutex_t;
 135 #define VLC_STATIC_MUTEX { false, { { false, 0 } } }
 136
 137 typedef HANDLE  vlc_cond_t;
 138 typedef HANDLE  vlc_sem_t;
 139
 140 typedef struct
 141 {
 142     vlc_mutex_t   mutex;
 143     vlc_cond_t    read_wait;
 144     vlc_cond_t    write_wait;
 145     unsigned long readers;
 146     unsigned long writers;
 147     DWORD         writer;
 148 } vlc_rwlock_t;
 149
 150 typedef DWORD   vlc_threadvar_t;
 151 typedef struct vlc_timer *vlc_timer_t;
 152 #endif
 153
 154 #if defined( WIN32 ) && !defined ETIMEDOUT
 155 #  define ETIMEDOUT 10060 /* This is the value in winsock.h. */
 156 #endif
 157
 158 /*****************************************************************************
 159  * Function definitions
 160  *****************************************************************************/
 161 VLC_EXPORT( void, vlc_mutex_init,    ( vlc_mutex_t * ) );
 162 VLC_EXPORT( void, vlc_mutex_init_recursive, ( vlc_mutex_t * ) );
 163 VLC_EXPORT( void, vlc_mutex_destroy, ( vlc_mutex_t * ) );
 164 VLC_EXPORT( void, vlc_mutex_lock, ( vlc_mutex_t * ) );
 165 VLC_EXPORT( int,  vlc_mutex_trylock, ( vlc_mutex_t * ) LIBVLC_USED );
 166 VLC_EXPORT( void, vlc_mutex_unlock, ( vlc_mutex_t * ) );
 167 VLC_EXPORT( void, vlc_cond_init,     ( vlc_cond_t * ) );
 168 VLC_EXPORT( void, vlc_cond_destroy,  ( vlc_cond_t * ) );
 169 VLC_EXPORT( void, vlc_cond_signal, (vlc_cond_t *) );
 170 VLC_EXPORT( void, vlc_cond_broadcast, (vlc_cond_t *) );
 171 VLC_EXPORT( void, vlc_cond_wait, (vlc_cond_t *, vlc_mutex_t *) );
 172 VLC_EXPORT( int,  vlc_cond_timedwait, (vlc_cond_t *, vlc_mutex_t *, mtime_t) );
 173 VLC_EXPORT( void, vlc_sem_init, (vlc_sem_t *, unsigned) );
 174 VLC_EXPORT( void, vlc_sem_destroy, (vlc_sem_t *) );
 175 VLC_EXPORT( int,  vlc_sem_post, (vlc_sem_t *) );
 176 VLC_EXPORT( void, vlc_sem_wait, (vlc_sem_t *) );
 177
 178 VLC_EXPORT( void, vlc_rwlock_init, (vlc_rwlock_t *) );
 179 VLC_EXPORT( void, vlc_rwlock_destroy, (vlc_rwlock_t *) );
 180 VLC_EXPORT( void, vlc_rwlock_rdlock, (vlc_rwlock_t *) );
 181 VLC_EXPORT( void, vlc_rwlock_wrlock, (vlc_rwlock_t *) );
 182 VLC_EXPORT( void, vlc_rwlock_unlock, (vlc_rwlock_t *) );
 183 VLC_EXPORT( int, vlc_threadvar_create, (vlc_threadvar_t * , void (*) (void *) ) );
 184 VLC_EXPORT( void, vlc_threadvar_delete, (vlc_threadvar_t *) );
 185 VLC_EXPORT( int, vlc_threadvar_set, (vlc_threadvar_t, void *) );
 186 VLC_EXPORT( void *, vlc_threadvar_get, (vlc_threadvar_t) );
 187 VLC_EXPORT( int,  vlc_thread_create, ( vlc_object_t *, const char *, int, const char *, void * ( * ) ( vlc_object_t * ), int ) LIBVLC_USED );
 188 VLC_EXPORT( int,  __vlc_thread_set_priority, ( vlc_object_t *, const char *, int, int ) );
 189 VLC_EXPORT( void, __vlc_thread_join,   ( vlc_object_t * ) );
 190
 191 VLC_EXPORT( int, vlc_clone, (vlc_thread_t *, void * (*) (void *), void *, int) LIBVLC_USED );
 192 VLC_EXPORT( void, vlc_cancel, (vlc_thread_t) );
 193 VLC_EXPORT( void, vlc_join, (vlc_thread_t, void **) );
 194 VLC_EXPORT (void, vlc_control_cancel, (int cmd, ...));
 195
 196 VLC_EXPORT( int, vlc_timer_create, (vlc_timer_t *, void (*) (void *), void *) LIBVLC_USED );
 197 VLC_EXPORT( void, vlc_timer_destroy, (vlc_timer_t) );
 198 VLC_EXPORT( void, vlc_timer_schedule, (vlc_timer_t, bool, mtime_t, mtime_t) );
 199 VLC_EXPORT( unsigned, vlc_timer_getoverrun, (vlc_timer_t) LIBVLC_USED );
 200
 201 #ifndef LIBVLC_USE_PTHREAD_CANCEL
 202 enum {
 203     VLC_DO_CANCEL,
 204     VLC_CLEANUP_PUSH,
 205     VLC_CLEANUP_POP,
 206 };
 207 #endif
 208
 209 VLC_EXPORT( int, vlc_savecancel, (void) );
 210 VLC_EXPORT( void, vlc_restorecancel, (int state) );
 211 VLC_EXPORT( void, vlc_testcancel, (void) );
 212
 213 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
 214 /**
 215  * Registers a new procedure to run if the thread is cancelled (or otherwise
 216  * exits prematurely). Any call to vlc_cleanup_push() <b>must</b> paired with a
 217  * call to either vlc_cleanup_pop() or vlc_cleanup_run(). Branching into or out
 218  * of the block between these two function calls is not allowed (read: it will
 219  * likely crash the whole process). If multiple procedures are registered,
 220  * they are handled in last-in first-out order.
 221  *
 222  * @param routine procedure to call if the thread ends
 223  * @param arg argument for the procedure
 224  */
 225 # define vlc_cleanup_push( routine, arg ) pthread_cleanup_push (routine, arg)
 226
 227 /**
 228  * Removes a cleanup procedure that was previously registered with
 229  * vlc_cleanup_push().
 230  */
 231 # define vlc_cleanup_pop( ) pthread_cleanup_pop (0)
 232
 233 /**
 234  * Removes a cleanup procedure that was previously registered with
 235  * vlc_cleanup_push(), and executes it.
 236  */
 237 # define vlc_cleanup_run( ) pthread_cleanup_pop (1)
 238 #else
 239 typedef struct vlc_cleanup_t vlc_cleanup_t;
 240
 241 struct vlc_cleanup_t
 242 {
 243     vlc_cleanup_t *next;
 244     void         (*proc) (void *);
 245     void          *data;
 246 };
 247
 248 /* This macros opens a code block on purpose. This is needed for multiple
 249  * calls within a single function. This also prevent Win32 developers from
 250  * writing code that would break on POSIX (POSIX opens a block as well). */
 251 # define vlc_cleanup_push( routine, arg ) \
 252     do { \
 253         vlc_cleanup_t vlc_cleanup_data = { NULL, routine, arg, }; \
 254         vlc_control_cancel (VLC_CLEANUP_PUSH, &vlc_cleanup_data)
 255
 256 # define vlc_cleanup_pop( ) \
 257         vlc_control_cancel (VLC_CLEANUP_POP); \
 258     } while (0)
 259
 260 # define vlc_cleanup_run( ) \
 261         vlc_control_cancel (VLC_CLEANUP_POP); \
 262         vlc_cleanup_data.proc (vlc_cleanup_data.data); \
 263     } while (0)
 264
 265 #endif /* LIBVLC_USE_PTHREAD_CANCEL */
 266
 267 static inline void vlc_cleanup_lock (void *lock)
 268 {
 269     vlc_mutex_unlock ((vlc_mutex_t *)lock);
 270 }
 271 #define mutex_cleanup_push( lock ) vlc_cleanup_push (vlc_cleanup_lock, lock)
 272
 273 # if defined (_POSIX_SPIN_LOCKS) && ((_POSIX_SPIN_LOCKS - 0) > 0)
 274 typedef pthread_spinlock_t vlc_spinlock_t;
 275
 276 /**
 277  * Initializes a spinlock.
 278  */
 279 static inline void vlc_spin_init (vlc_spinlock_t *spin)
 280 {
 281     if (pthread_spin_init (spin, PTHREAD_PROCESS_PRIVATE))
 282         abort ();
 283 }
 284
 285 /**
 286  * Acquires a spinlock.
 287  */
 288 static inline void vlc_spin_lock (vlc_spinlock_t *spin)
 289 {
 290     pthread_spin_lock (spin);
 291 }
 292
 293 /**
 294  * Releases a spinlock.
 295  */
 296 static inline void vlc_spin_unlock (vlc_spinlock_t *spin)
 297 {
 298     pthread_spin_unlock (spin);
 299 }
 300
 301 /**
 302  * Deinitializes a spinlock.
 303  */
 304 static inline void vlc_spin_destroy (vlc_spinlock_t *spin)
 305 {
 306     pthread_spin_destroy (spin);
 307 }
 308
 309 #elif defined (WIN32) && !defined (UNDER_CE)
 310
 311 typedef CRITICAL_SECTION vlc_spinlock_t;
 312
 313 /**
 314  * Initializes a spinlock.
 315  */
 316 static inline void vlc_spin_init (vlc_spinlock_t *spin)
 317 {
 318     if (!InitializeCriticalSectionAndSpinCount(spin, 4000))
 319         abort ();
 320 }
 321
 322 /**
 323  * Acquires a spinlock.
 324  */
 325 static inline void vlc_spin_lock (vlc_spinlock_t *spin)
 326 {
 327     EnterCriticalSection(spin);
 328 }
 329
 330 /**
 331  * Releases a spinlock.
 332  */
 333 static inline void vlc_spin_unlock (vlc_spinlock_t *spin)
 334 {
 335     LeaveCriticalSection(spin);
 336 }
 337
 338 /**
 339  * Deinitializes a spinlock.
 340  */
 341 static inline void vlc_spin_destroy (vlc_spinlock_t *spin)
 342 {
 343     DeleteCriticalSection(spin);
 344 }
 345
 346 #else
 347
 348 /* Fallback to plain mutexes if spinlocks are not available */
 349 typedef vlc_mutex_t vlc_spinlock_t;
 350
 351 static inline void vlc_spin_init (vlc_spinlock_t *spin)
 352 {
 353     vlc_mutex_init (spin);
 354 }
 355
 356 # define vlc_spin_lock    vlc_mutex_lock
 357 # define vlc_spin_unlock  vlc_mutex_unlock
 358 # define vlc_spin_destroy vlc_mutex_destroy
 359 #endif
 360
 361 /**
 362  * Issues a full memory barrier.
 363  */
 364 #if defined (__APPLE__)
 365 # include <libkern/OSAtomic.h> /* OSMemoryBarrier() */
 366 #endif
 367 static inline void barrier (void)
 368 {
 369 #if defined (__GNUC__) && !defined (__APPLE__) && \
 370             ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1))
 371     __sync_synchronize ();
 372 #elif defined(__APPLE__)
 373     OSMemoryBarrier ();
 374 #elif defined(__powerpc__)
 375     asm volatile ("sync":::"memory");
 376 #elif 0 // defined(__i386__) /*  Requires SSE2 support */
 377     asm volatile ("mfence":::"memory");
 378 #else
 379     vlc_spinlock_t spin;
 380     vlc_spin_init (&spin);
 381     vlc_spin_lock (&spin);
 382     vlc_spin_unlock (&spin);
 383     vlc_spin_destroy (&spin);
 384 #endif
 385 }
 386
 387 /*****************************************************************************
 388  * vlc_thread_create: create a thread
 389  *****************************************************************************/
 390 #define vlc_thread_create( P_THIS, PSZ_NAME, FUNC, PRIORITY )         \
 391     vlc_thread_create( VLC_OBJECT(P_THIS), __FILE__, __LINE__, PSZ_NAME, FUNC, PRIORITY )
 392
 393 /*****************************************************************************
 394  * vlc_thread_set_priority: set the priority of the calling thread
 395  *****************************************************************************/
 396 #define vlc_thread_set_priority( P_THIS, PRIORITY )                         \
 397     __vlc_thread_set_priority( VLC_OBJECT(P_THIS), __FILE__, __LINE__, PRIORITY )
 398
 399 /*****************************************************************************
 400  * vlc_thread_join: wait until a thread exits
 401  *****************************************************************************/
 402 #define vlc_thread_join( P_THIS )                                           \
 403     __vlc_thread_join( VLC_OBJECT(P_THIS) )
 404
 405 #ifdef __cplusplus
 406 /**
 407  * Helper C++ class to lock a mutex.
 408  * The mutex is locked when the object is created, and unlocked when the object
 409  * is destroyed.
 410  */
 411 class vlc_mutex_locker
 412 {
 413     private:
 414         vlc_mutex_t *lock;
 415     public:
 416         vlc_mutex_locker (vlc_mutex_t *m) : lock (m)
 417         {
 418             vlc_mutex_lock (lock);
 419         }
 420
 421         ~vlc_mutex_locker (void)
 422         {
 423             vlc_mutex_unlock (lock);
 424         }
 425 };
 426 #endif
 427
 428 #endif /* !_VLC_THREADS_H */