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
  49 /* Unnamed POSIX semaphores not supported on Mac OS X, use Mach semaphores instead */
  50 #   if defined (__APPLE__)
  51 #      include <mach/semaphore.h>
  52 #      include <mach/task.h>
  53 #   else
  54 #      include <semaphore.h>
  55 #   endif
  56
  57 #endif
  58
  59 /*****************************************************************************
  60  * Constants
  61  *****************************************************************************/
  62
  63 /* Thread priorities */
  64 #ifdef __APPLE__
  65 #   define VLC_THREAD_PRIORITY_LOW      0
  66 #   define VLC_THREAD_PRIORITY_INPUT   22
  67 #   define VLC_THREAD_PRIORITY_AUDIO   22
  68 #   define VLC_THREAD_PRIORITY_VIDEO    0
  69 #   define VLC_THREAD_PRIORITY_OUTPUT  22
  70 #   define VLC_THREAD_PRIORITY_HIGHEST 22
  71
  72 #elif defined(LIBVLC_USE_PTHREAD)
  73 #   define VLC_THREAD_PRIORITY_LOW      0
  74 #   define VLC_THREAD_PRIORITY_INPUT   10
  75 #   define VLC_THREAD_PRIORITY_AUDIO    5
  76 #   define VLC_THREAD_PRIORITY_VIDEO    0
  77 #   define VLC_THREAD_PRIORITY_OUTPUT  15
  78 #   define VLC_THREAD_PRIORITY_HIGHEST 20
  79
  80 #elif defined(WIN32) || defined(UNDER_CE)
  81 /* Define different priorities for WinNT/2K/XP and Win9x/Me */
  82 #   define VLC_THREAD_PRIORITY_LOW 0
  83 #   define VLC_THREAD_PRIORITY_INPUT \
  84         THREAD_PRIORITY_ABOVE_NORMAL
  85 #   define VLC_THREAD_PRIORITY_AUDIO \
  86         THREAD_PRIORITY_HIGHEST
  87 #   define VLC_THREAD_PRIORITY_VIDEO 0
  88 #   define VLC_THREAD_PRIORITY_OUTPUT \
  89         THREAD_PRIORITY_ABOVE_NORMAL
  90 #   define VLC_THREAD_PRIORITY_HIGHEST \
  91         THREAD_PRIORITY_TIME_CRITICAL
  92
  93 #else
  94 #   define VLC_THREAD_PRIORITY_LOW 0
  95 #   define VLC_THREAD_PRIORITY_INPUT 0
  96 #   define VLC_THREAD_PRIORITY_AUDIO 0
  97 #   define VLC_THREAD_PRIORITY_VIDEO 0
  98 #   define VLC_THREAD_PRIORITY_OUTPUT 0
  99 #   define VLC_THREAD_PRIORITY_HIGHEST 0
 100
 101 #endif
 102
 103 /*****************************************************************************
 104  * Type definitions
 105  *****************************************************************************/
 106
 107 #if defined (LIBVLC_USE_PTHREAD)
 108 typedef pthread_t       vlc_thread_t;
 109 typedef pthread_mutex_t vlc_mutex_t;
 110 #define VLC_STATIC_MUTEX PTHREAD_MUTEX_INITIALIZER
 111 typedef pthread_cond_t  vlc_cond_t;
 112 #define VLC_STATIC_COND  PTHREAD_COND_INITIALIZER
 113 typedef pthread_rwlock_t vlc_rwlock_t;
 114 #define VLC_STATIC_RWLOCK PTHREAD_RWLOCK_INITIALIZER
 115 typedef pthread_key_t   vlc_threadvar_t;
 116 typedef struct vlc_timer *vlc_timer_t;
 117
 118 #if defined (__APPLE__)
 119 typedef semaphore_t     vlc_sem_t;
 120 #else
 121 typedef sem_t           vlc_sem_t;
 122 #endif
 123
 124 #elif defined( WIN32 )
 125 typedef struct vlc_thread *vlc_thread_t;
 126
 127 typedef struct
 128 {
 129     bool dynamic;
 130     union
 131     {
 132         struct
 133         {
 134             bool locked;
 135             unsigned long contention;
 136         };
 137         CRITICAL_SECTION mutex;
 138     };
 139 } vlc_mutex_t;
 140 #define VLC_STATIC_MUTEX { false, { { false, 0 } } }
 141
 142 typedef struct
 143 {
 144     HANDLE   handle;
 145     unsigned clock;
 146 } vlc_cond_t;
 147 #define VLC_STATIC_COND { 0, 0 }
 148
 149 typedef HANDLE  vlc_sem_t;
 150
 151 typedef struct
 152 {
 153     vlc_mutex_t   mutex;
 154     vlc_cond_t    wait;
 155     unsigned long readers;
 156     unsigned long writers;
 157     DWORD         writer;
 158 } vlc_rwlock_t;
 159 #define VLC_STATIC_RWLOCK \
 160     { VLC_STATIC_MUTEX, VLC_STATIC_COND, 0, 0, 0 }
 161
 162 typedef struct vlc_threadvar *vlc_threadvar_t;
 163 typedef struct vlc_timer *vlc_timer_t;
 164 #endif
 165
 166 #if defined( WIN32 ) && !defined ETIMEDOUT
 167 #  define ETIMEDOUT 10060 /* This is the value in winsock.h. */
 168 #endif
 169
 170 /*****************************************************************************
 171  * Function definitions
 172  *****************************************************************************/
 173 VLC_API void vlc_mutex_init( vlc_mutex_t * );
 174 VLC_API void vlc_mutex_init_recursive( vlc_mutex_t * );
 175 VLC_API void vlc_mutex_destroy( vlc_mutex_t * );
 176 VLC_API void vlc_mutex_lock( vlc_mutex_t * );
 177 VLC_API int vlc_mutex_trylock( vlc_mutex_t * ) VLC_USED;
 178 VLC_API void vlc_mutex_unlock( vlc_mutex_t * );
 179 VLC_API void vlc_cond_init( vlc_cond_t * );
 180 VLC_API void vlc_cond_init_daytime( vlc_cond_t * );
 181 VLC_API void vlc_cond_destroy( vlc_cond_t * );
 182 VLC_API void vlc_cond_signal(vlc_cond_t *);
 183 VLC_API void vlc_cond_broadcast(vlc_cond_t *);
 184 VLC_API void vlc_cond_wait(vlc_cond_t *, vlc_mutex_t *);
 185 VLC_API int vlc_cond_timedwait(vlc_cond_t *, vlc_mutex_t *, mtime_t);
 186 VLC_API void vlc_sem_init(vlc_sem_t *, unsigned);
 187 VLC_API void vlc_sem_destroy(vlc_sem_t *);
 188 VLC_API int vlc_sem_post(vlc_sem_t *);
 189 VLC_API void vlc_sem_wait(vlc_sem_t *);
 190
 191 VLC_API void vlc_rwlock_init(vlc_rwlock_t *);
 192 VLC_API void vlc_rwlock_destroy(vlc_rwlock_t *);
 193 VLC_API void vlc_rwlock_rdlock(vlc_rwlock_t *);
 194 VLC_API void vlc_rwlock_wrlock(vlc_rwlock_t *);
 195 VLC_API void vlc_rwlock_unlock(vlc_rwlock_t *);
 196 VLC_API int vlc_threadvar_create(vlc_threadvar_t * , void (*) (void *) );
 197 VLC_API void vlc_threadvar_delete(vlc_threadvar_t *);
 198 VLC_API int vlc_threadvar_set(vlc_threadvar_t, void *);
 199 VLC_API void * vlc_threadvar_get(vlc_threadvar_t);
 200
 201 VLC_API int vlc_clone(vlc_thread_t *, void * (*) (void *), void *, int) VLC_USED;
 202 VLC_API void vlc_cancel(vlc_thread_t);
 203 VLC_API void vlc_join(vlc_thread_t, void **);
 204 VLC_API void vlc_control_cancel (int cmd, ...);
 205
 206 VLC_API mtime_t mdate(void);
 207 VLC_API void mwait(mtime_t deadline);
 208 VLC_API void msleep(mtime_t delay);
 209
 210 #define VLC_HARD_MIN_SLEEP   10000 /* 10 milliseconds = 1 tick at 100Hz */
 211 #define VLC_SOFT_MIN_SLEEP 9000000 /* 9 seconds */
 212
 213 #if VLC_GCC_VERSION(4,3)
 214 /* Linux has 100, 250, 300 or 1000Hz
 215  *
 216  * HZ=100 by default on FreeBSD, but some architectures use a 1000Hz timer
 217  */
 218
 219 static
 220 __attribute__((unused))
 221 __attribute__((noinline))
 222 __attribute__((error("sorry, cannot sleep for such short a time")))
 223 mtime_t impossible_delay( mtime_t delay )
 224 {
 225     (void) delay;
 226     return VLC_HARD_MIN_SLEEP;
 227 }
 228
 229 static
 230 __attribute__((unused))
 231 __attribute__((noinline))
 232 __attribute__((warning("use proper event handling instead of short delay")))
 233 mtime_t harmful_delay( mtime_t delay )
 234 {
 235     return delay;
 236 }
 237
 238 # define check_delay( d ) \
 239     ((__builtin_constant_p(d < VLC_HARD_MIN_SLEEP) \
 240    && (d < VLC_HARD_MIN_SLEEP)) \
 241        ? impossible_delay(d) \
 242        : ((__builtin_constant_p(d < VLC_SOFT_MIN_SLEEP) \
 243        && (d < VLC_SOFT_MIN_SLEEP)) \
 244            ? harmful_delay(d) \
 245            : d))
 246
 247 static
 248 __attribute__((unused))
 249 __attribute__((noinline))
 250 __attribute__((error("deadlines can not be constant")))
 251 mtime_t impossible_deadline( mtime_t deadline )
 252 {
 253     return deadline;
 254 }
 255
 256 # define check_deadline( d ) \
 257     (__builtin_constant_p(d) ? impossible_deadline(d) : d)
 258 #else
 259 # define check_delay(d) (d)
 260 # define check_deadline(d) (d)
 261 #endif
 262
 263 #define msleep(d) msleep(check_delay(d))
 264 #define mwait(d) mwait(check_deadline(d))
 265
 266 VLC_API int vlc_timer_create(vlc_timer_t *, void (*) (void *), void *) VLC_USED;
 267 VLC_API void vlc_timer_destroy(vlc_timer_t);
 268 VLC_API void vlc_timer_schedule(vlc_timer_t, bool, mtime_t, mtime_t);
 269 VLC_API unsigned vlc_timer_getoverrun(vlc_timer_t) VLC_USED;
 270
 271 VLC_API unsigned vlc_GetCPUCount(void);
 272
 273 #ifndef LIBVLC_USE_PTHREAD_CANCEL
 274 enum {
 275     VLC_CLEANUP_PUSH,
 276     VLC_CLEANUP_POP,
 277 };
 278 #endif
 279
 280 VLC_API int vlc_savecancel(void);
 281 VLC_API void vlc_restorecancel(int state);
 282 VLC_API void vlc_testcancel(void);
 283
 284 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
 285 /**
 286  * Registers a new procedure to run if the thread is cancelled (or otherwise
 287  * exits prematurely). Any call to vlc_cleanup_push() <b>must</b> paired with a
 288  * call to either vlc_cleanup_pop() or vlc_cleanup_run(). Branching into or out
 289  * of the block between these two function calls is not allowed (read: it will
 290  * likely crash the whole process). If multiple procedures are registered,
 291  * they are handled in last-in first-out order.
 292  *
 293  * @param routine procedure to call if the thread ends
 294  * @param arg argument for the procedure
 295  */
 296 # define vlc_cleanup_push( routine, arg ) pthread_cleanup_push (routine, arg)
 297
 298 /**
 299  * Removes a cleanup procedure that was previously registered with
 300  * vlc_cleanup_push().
 301  */
 302 # define vlc_cleanup_pop( ) pthread_cleanup_pop (0)
 303
 304 /**
 305  * Removes a cleanup procedure that was previously registered with
 306  * vlc_cleanup_push(), and executes it.
 307  */
 308 # define vlc_cleanup_run( ) pthread_cleanup_pop (1)
 309 #else
 310 typedef struct vlc_cleanup_t vlc_cleanup_t;
 311
 312 struct vlc_cleanup_t
 313 {
 314     vlc_cleanup_t *next;
 315     void         (*proc) (void *);
 316     void          *data;
 317 };
 318
 319 /* This macros opens a code block on purpose. This is needed for multiple
 320  * calls within a single function. This also prevent Win32 developers from
 321  * writing code that would break on POSIX (POSIX opens a block as well). */
 322 # define vlc_cleanup_push( routine, arg ) \
 323     do { \
 324         vlc_cleanup_t vlc_cleanup_data = { NULL, routine, arg, }; \
 325         vlc_control_cancel (VLC_CLEANUP_PUSH, &vlc_cleanup_data)
 326
 327 # define vlc_cleanup_pop( ) \
 328         vlc_control_cancel (VLC_CLEANUP_POP); \
 329     } while (0)
 330
 331 # define vlc_cleanup_run( ) \
 332         vlc_control_cancel (VLC_CLEANUP_POP); \
 333         vlc_cleanup_data.proc (vlc_cleanup_data.data); \
 334     } while (0)
 335
 336 #endif /* LIBVLC_USE_PTHREAD_CANCEL */
 337
 338 static inline void vlc_cleanup_lock (void *lock)
 339 {
 340     vlc_mutex_unlock ((vlc_mutex_t *)lock);
 341 }
 342 #define mutex_cleanup_push( lock ) vlc_cleanup_push (vlc_cleanup_lock, lock)
 343
 344 # if defined (_POSIX_SPIN_LOCKS) && ((_POSIX_SPIN_LOCKS - 0) > 0)
 345 typedef pthread_spinlock_t vlc_spinlock_t;
 346
 347 /**
 348  * Initializes a spinlock.
 349  */
 350 static inline void vlc_spin_init (vlc_spinlock_t *spin)
 351 {
 352     if (pthread_spin_init (spin, PTHREAD_PROCESS_PRIVATE))
 353         abort ();
 354 }
 355
 356 /**
 357  * Acquires a spinlock.
 358  */
 359 static inline void vlc_spin_lock (vlc_spinlock_t *spin)
 360 {
 361     pthread_spin_lock (spin);
 362 }
 363
 364 /**
 365  * Releases a spinlock.
 366  */
 367 static inline void vlc_spin_unlock (vlc_spinlock_t *spin)
 368 {
 369     pthread_spin_unlock (spin);
 370 }
 371
 372 /**
 373  * Deinitializes a spinlock.
 374  */
 375 static inline void vlc_spin_destroy (vlc_spinlock_t *spin)
 376 {
 377     pthread_spin_destroy (spin);
 378 }
 379
 380 #elif defined (WIN32) && !defined (UNDER_CE)
 381
 382 typedef CRITICAL_SECTION vlc_spinlock_t;
 383
 384 /**
 385  * Initializes a spinlock.
 386  */
 387 static inline void vlc_spin_init (vlc_spinlock_t *spin)
 388 {
 389     if (!InitializeCriticalSectionAndSpinCount(spin, 4000))
 390         abort ();
 391 }
 392
 393 /**
 394  * Acquires a spinlock.
 395  */
 396 static inline void vlc_spin_lock (vlc_spinlock_t *spin)
 397 {
 398     EnterCriticalSection(spin);
 399 }
 400
 401 /**
 402  * Releases a spinlock.
 403  */
 404 static inline void vlc_spin_unlock (vlc_spinlock_t *spin)
 405 {
 406     LeaveCriticalSection(spin);
 407 }
 408
 409 /**
 410  * Deinitializes a spinlock.
 411  */
 412 static inline void vlc_spin_destroy (vlc_spinlock_t *spin)
 413 {
 414     DeleteCriticalSection(spin);
 415 }
 416
 417 #else
 418
 419 /* Fallback to plain mutexes if spinlocks are not available */
 420 typedef vlc_mutex_t vlc_spinlock_t;
 421
 422 static inline void vlc_spin_init (vlc_spinlock_t *spin)
 423 {
 424     vlc_mutex_init (spin);
 425 }
 426
 427 # define vlc_spin_lock    vlc_mutex_lock
 428 # define vlc_spin_unlock  vlc_mutex_unlock
 429 # define vlc_spin_destroy vlc_mutex_destroy
 430 #endif
 431
 432 /**
 433  * Issues a full memory barrier.
 434  */
 435 #if defined (__APPLE__)
 436 # include <libkern/OSAtomic.h> /* OSMemoryBarrier() */
 437 #endif
 438 static inline void barrier (void)
 439 {
 440 #if defined (__GNUC__) && !defined (__APPLE__) && \
 441             ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1))
 442     __sync_synchronize ();
 443 #elif defined(__APPLE__)
 444     OSMemoryBarrier ();
 445 #elif defined(__powerpc__)
 446     asm volatile ("sync":::"memory");
 447 #elif 0 // defined(__i386__) /*  Requires SSE2 support */
 448     asm volatile ("mfence":::"memory");
 449 #else
 450     vlc_spinlock_t spin;
 451     vlc_spin_init (&spin);
 452     vlc_spin_lock (&spin);
 453     vlc_spin_unlock (&spin);
 454     vlc_spin_destroy (&spin);
 455 #endif
 456 }
 457
 458 #ifdef __cplusplus
 459 /**
 460  * Helper C++ class to lock a mutex.
 461  * The mutex is locked when the object is created, and unlocked when the object
 462  * is destroyed.
 463  */
 464 class vlc_mutex_locker
 465 {
 466     private:
 467         vlc_mutex_t *lock;
 468     public:
 469         vlc_mutex_locker (vlc_mutex_t *m) : lock (m)
 470         {
 471             vlc_mutex_lock (lock);
 472         }
 473
 474         ~vlc_mutex_locker (void)
 475         {
 476             vlc_mutex_unlock (lock);
 477         }
 478 };
 479 #endif
 480
 481 enum {
 482    VLC_AVCODEC_MUTEX = 0,
 483    VLC_GCRYPT_MUTEX,
 484    VLC_XLIB_MUTEX,
 485    VLC_MOSAIC_MUTEX,
 486    VLC_HIGHLIGHT_MUTEX,
 487    /* Insert new entry HERE */
 488    VLC_MAX_MUTEX
 489 };
 490
 491 VLC_API void vlc_global_mutex( unsigned, bool );
 492 #define vlc_global_lock( n ) vlc_global_mutex( n, true )
 493 #define vlc_global_unlock( n ) vlc_global_mutex( n, false )
 494
 495 #endif /* !_VLC_THREADS_H */