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 #   include <errno.h>                                           /* WinCE API */
  39 #elif defined( WIN32 )
  40 #   include <process.h>                                         /* Win32 API */
  41 #   include <errno.h>
  42
  43 #else                                         /* pthreads (like Linux & BSD) */
  44 #   define LIBVLC_USE_PTHREAD 1
  45 #   define LIBVLC_USE_PTHREAD_CANCEL 1
  46 #   define _APPLE_C_SOURCE    1 /* Proper pthread semantics on OSX */
  47
  48 #   include <stdlib.h> /* lldiv_t definition (only in C99) */
  49 #   include <unistd.h> /* _POSIX_SPIN_LOCKS */
  50 #   include <pthread.h>
  51     /* Needed for pthread_cond_timedwait */
  52 #   include <errno.h>
  53 #   include <time.h>
  54
  55 #endif
  56
  57 /*****************************************************************************
  58  * Constants
  59  *****************************************************************************/
  60
  61 /* Thread priorities */
  62 #ifdef __APPLE__
  63 #   define VLC_THREAD_PRIORITY_LOW      0
  64 #   define VLC_THREAD_PRIORITY_INPUT   22
  65 #   define VLC_THREAD_PRIORITY_AUDIO   22
  66 #   define VLC_THREAD_PRIORITY_VIDEO    0
  67 #   define VLC_THREAD_PRIORITY_OUTPUT  22
  68 #   define VLC_THREAD_PRIORITY_HIGHEST 22
  69
  70 #elif defined(LIBVLC_USE_PTHREAD)
  71 #   define VLC_THREAD_PRIORITY_LOW      0
  72 #   define VLC_THREAD_PRIORITY_INPUT   10
  73 #   define VLC_THREAD_PRIORITY_AUDIO    5
  74 #   define VLC_THREAD_PRIORITY_VIDEO    0
  75 #   define VLC_THREAD_PRIORITY_OUTPUT  15
  76 #   define VLC_THREAD_PRIORITY_HIGHEST 20
  77
  78 #elif defined(WIN32) || defined(UNDER_CE)
  79 /* Define different priorities for WinNT/2K/XP and Win9x/Me */
  80 #   define VLC_THREAD_PRIORITY_LOW 0
  81 #   define VLC_THREAD_PRIORITY_INPUT \
  82         THREAD_PRIORITY_ABOVE_NORMAL
  83 #   define VLC_THREAD_PRIORITY_AUDIO \
  84         THREAD_PRIORITY_HIGHEST
  85 #   define VLC_THREAD_PRIORITY_VIDEO 0
  86 #   define VLC_THREAD_PRIORITY_OUTPUT \
  87         THREAD_PRIORITY_ABOVE_NORMAL
  88 #   define VLC_THREAD_PRIORITY_HIGHEST \
  89         THREAD_PRIORITY_TIME_CRITICAL
  90
  91 #else
  92 #   define VLC_THREAD_PRIORITY_LOW 0
  93 #   define VLC_THREAD_PRIORITY_INPUT 0
  94 #   define VLC_THREAD_PRIORITY_AUDIO 0
  95 #   define VLC_THREAD_PRIORITY_VIDEO 0
  96 #   define VLC_THREAD_PRIORITY_OUTPUT 0
  97 #   define VLC_THREAD_PRIORITY_HIGHEST 0
  98
  99 #endif
 100
 101 /*****************************************************************************
 102  * Type definitions
 103  *****************************************************************************/
 104
 105 #if defined (LIBVLC_USE_PTHREAD)
 106 typedef pthread_t       vlc_thread_t;
 107 typedef pthread_mutex_t vlc_mutex_t;
 108 #define VLC_STATIC_MUTEX PTHREAD_MUTEX_INITIALIZER
 109 typedef pthread_cond_t  vlc_cond_t;
 110 typedef pthread_key_t   vlc_threadvar_t;
 111
 112 #elif defined( WIN32 )
 113 typedef struct
 114 {
 115     HANDLE handle;
 116     void  *(*entry) (void *);
 117     void  *data;
 118 } *vlc_thread_t;
 119
 120 typedef struct
 121 {
 122     CRITICAL_SECTION mutex;
 123     LONG initialized;
 124 } vlc_mutex_t;
 125 #define VLC_STATIC_MUTEX { .initialized = 0, }
 126
 127 typedef HANDLE  vlc_cond_t;
 128 typedef DWORD   vlc_threadvar_t;
 129
 130 #endif
 131
 132 #if defined( WIN32 ) && !defined ETIMEDOUT
 133 #  define ETIMEDOUT 10060 /* This is the value in winsock.h. */
 134 #endif
 135
 136 /*****************************************************************************
 137  * Function definitions
 138  *****************************************************************************/
 139 VLC_EXPORT( int,  vlc_mutex_init,    ( vlc_mutex_t * ) );
 140 VLC_EXPORT( int,  vlc_mutex_init_recursive, ( vlc_mutex_t * ) );
 141 VLC_EXPORT( void, vlc_mutex_destroy, ( vlc_mutex_t * ) );
 142 VLC_EXPORT( void, vlc_mutex_lock, ( vlc_mutex_t * ) );
 143 VLC_EXPORT( void, vlc_mutex_unlock, ( vlc_mutex_t * ) );
 144 VLC_EXPORT( int,  vlc_cond_init,     ( vlc_cond_t * ) );
 145 VLC_EXPORT( void, vlc_cond_destroy,  ( vlc_cond_t * ) );
 146 VLC_EXPORT( void, vlc_cond_signal, (vlc_cond_t *) );
 147 VLC_EXPORT( void, vlc_cond_broadcast, (vlc_cond_t *) );
 148 VLC_EXPORT( void, vlc_cond_wait, (vlc_cond_t *, vlc_mutex_t *) );
 149 VLC_EXPORT( int, vlc_cond_timedwait, (vlc_cond_t *, vlc_mutex_t *, mtime_t) );
 150 VLC_EXPORT( int, vlc_threadvar_create, (vlc_threadvar_t * , void (*) (void *) ) );
 151 VLC_EXPORT( void, vlc_threadvar_delete, (vlc_threadvar_t *) );
 152 VLC_EXPORT( int,  __vlc_thread_create, ( vlc_object_t *, const char *, int, const char *, void * ( * ) ( vlc_object_t * ), int, bool ) );
 153 VLC_EXPORT( int,  __vlc_thread_set_priority, ( vlc_object_t *, const char *, int, int ) );
 154 VLC_EXPORT( void, __vlc_thread_join,   ( vlc_object_t * ) );
 155
 156 VLC_EXPORT( int, vlc_clone, (vlc_thread_t *, void * (*) (void *), void *, int) );
 157 VLC_EXPORT( void, vlc_cancel, (vlc_thread_t) );
 158 VLC_EXPORT( void, vlc_join, (vlc_thread_t, void **) );
 159 VLC_EXPORT (void, vlc_control_cancel, (int cmd, ...));
 160
 161 #ifndef LIBVLC_USE_PTHREAD_CANCEL
 162 enum {
 163     VLC_SAVE_CANCEL,
 164     VLC_RESTORE_CANCEL,
 165     VLC_TEST_CANCEL,
 166     VLC_DO_CANCEL,
 167     VLC_CLEANUP_PUSH,
 168     VLC_CLEANUP_POP,
 169 };
 170 #endif
 171
 172 VLC_EXPORT(void, vlc_thread_ready, (vlc_object_t *obj));
 173 #define vlc_thread_ready(o) vlc_thread_ready(VLC_OBJECT(o))
 174
 175 /**
 176  * Save the cancellation state and disable cancellation for the calling thread.
 177  * This function must be called before entering a piece of code that is not
 178  * cancellation-safe.
 179  * @return Previous cancellation state (opaque value).
 180  */
 181 static inline int vlc_savecancel (void)
 182 {
 183     int state;
 184 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
 185     (void) pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
 186 #else
 187     vlc_control_cancel (VLC_SAVE_CANCEL, &state);
 188 #endif
 189     return state;
 190 }
 191
 192 /**
 193  * Restore the cancellation state for the calling thread.
 194  * @param state previous state as returned by vlc_savecancel().
 195  * @return Nothing, always succeeds.
 196  */
 197 static inline void vlc_restorecancel (int state)
 198 {
 199 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
 200     (void) pthread_setcancelstate (state, NULL);
 201 #else
 202     vlc_control_cancel (VLC_RESTORE_CANCEL, state);
 203 #endif
 204 }
 205
 206 /**
 207  * Issues an explicit deferred cancellation point.
 208  * This has no effect if thread cancellation is disabled.
 209  * This can be called when there is a rather slow non-sleeping operation.
 210  */
 211 static inline void vlc_testcancel (void)
 212 {
 213 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
 214     pthread_testcancel ();
 215 #else
 216     vlc_control_cancel (VLC_TEST_CANCEL);
 217 #endif
 218 }
 219
 220 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
 221 /**
 222  * Registers a new procedure to run if the thread is cancelled (or otherwise
 223  * exits prematurely). Any call to vlc_cleanup_push() <b>must</b> paired with a
 224  * call to either vlc_cleanup_pop() or vlc_cleanup_run(). Branching into or out
 225  * of the block between these two function calls is not allowed (read: it will
 226  * likely crash the whole process). If multiple procedures are registered,
 227  * they are handled in last-in first-out order.
 228  *
 229  * @param routine procedure to call if the thread ends
 230  * @param arg argument for the procedure
 231  */
 232 # define vlc_cleanup_push( routine, arg ) pthread_cleanup_push (routine, arg)
 233
 234 /**
 235  * Removes a cleanup procedure that was previously registered with
 236  * vlc_cleanup_push().
 237  */
 238 # define vlc_cleanup_pop( ) pthread_cleanup_pop (0)
 239
 240 /**
 241  * Removes a cleanup procedure that was previously registered with
 242  * vlc_cleanup_push(), and executes it.
 243  */
 244 # define vlc_cleanup_run( ) pthread_cleanup_pop (1)
 245 #else
 246 typedef struct vlc_cleanup_t vlc_cleanup_t;
 247
 248 struct vlc_cleanup_t
 249 {
 250     vlc_cleanup_t *next;
 251     void         (*proc) (void *);
 252     void          *data;
 253 };
 254
 255 /* This macros opens a code block on purpose. This is needed for multiple
 256  * calls within a single function. This also prevent Win32 developpers from
 257  * writing code that would break on POSIX (POSIX opens a block as well). */
 258 # define vlc_cleanup_push( routine, arg ) \
 259     do { \
 260         vlc_cleanup_t vlc_cleanup_data = { NULL, routine, arg, }; \
 261         vlc_control_cancel (VLC_CLEANUP_PUSH, &vlc_cleanup_data)
 262
 263 # define vlc_cleanup_pop( ) \
 264         vlc_control_cancel (VLC_CLEANUP_POP); \
 265     } while (0)
 266
 267 # define vlc_cleanup_run( ) \
 268         vlc_control_cancel (VLC_CLEANUP_POP); \
 269         vlc_cleanup_data.proc (vlc_cleanup_data.data); \
 270     } while (0)
 271
 272 #endif /* LIBVLC_USE_PTHREAD_CANCEL */
 273
 274 static inline void vlc_cleanup_lock (void *lock)
 275 {
 276     vlc_mutex_unlock ((vlc_mutex_t *)lock);
 277 }
 278 #define mutex_cleanup_push( lock ) vlc_cleanup_push (vlc_cleanup_lock, lock)
 279
 280 /*****************************************************************************
 281  * vlc_threadvar_set: create: set the value of a thread-local variable
 282  *****************************************************************************/
 283 static inline int vlc_threadvar_set( vlc_threadvar_t * p_tls, void *p_value )
 284 {
 285     int i_ret;
 286
 287 #if defined(LIBVLC_USE_PTHREAD)
 288     i_ret = pthread_setspecific( *p_tls, p_value );
 289
 290 #elif defined( UNDER_CE ) || defined( WIN32 )
 291     i_ret = TlsSetValue( *p_tls, p_value ) ? EINVAL : 0;
 292
 293 #endif
 294
 295     return i_ret;
 296 }
 297
 298 /*****************************************************************************
 299  * vlc_threadvar_get: create: get the value of a thread-local variable
 300  *****************************************************************************/
 301 static inline void* vlc_threadvar_get( vlc_threadvar_t * p_tls )
 302 {
 303     void *p_ret;
 304
 305 #if defined(LIBVLC_USE_PTHREAD)
 306     p_ret = pthread_getspecific( *p_tls );
 307
 308 #elif defined( UNDER_CE ) || defined( WIN32 )
 309     p_ret = TlsGetValue( *p_tls );
 310
 311 #endif
 312
 313     return p_ret;
 314 }
 315
 316 # if defined (_POSIX_SPIN_LOCKS) && ((_POSIX_SPIN_LOCKS - 0) > 0)
 317 typedef pthread_spinlock_t vlc_spinlock_t;
 318
 319 /**
 320  * Initializes a spinlock.
 321  */
 322 static inline int vlc_spin_init (vlc_spinlock_t *spin)
 323 {
 324     return pthread_spin_init (spin, PTHREAD_PROCESS_PRIVATE);
 325 }
 326
 327 /**
 328  * Acquires a spinlock.
 329  */
 330 static inline void vlc_spin_lock (vlc_spinlock_t *spin)
 331 {
 332     pthread_spin_lock (spin);
 333 }
 334
 335 /**
 336  * Releases a spinlock.
 337  */
 338 static inline void vlc_spin_unlock (vlc_spinlock_t *spin)
 339 {
 340     pthread_spin_unlock (spin);
 341 }
 342
 343 /**
 344  * Deinitializes a spinlock.
 345  */
 346 static inline void vlc_spin_destroy (vlc_spinlock_t *spin)
 347 {
 348     pthread_spin_destroy (spin);
 349 }
 350
 351 #elif defined( WIN32 )
 352
 353 typedef CRITICAL_SECTION vlc_spinlock_t;
 354
 355 /**
 356  * Initializes a spinlock.
 357  */
 358 static inline int vlc_spin_init (vlc_spinlock_t *spin)
 359 {
 360 #ifdef UNDER_CE
 361     InitializeCriticalSection(spin);
 362     return 0;
 363 #else
 364     return !InitializeCriticalSectionAndSpinCount(spin, 4000);
 365 #endif
 366 }
 367
 368 /**
 369  * Acquires a spinlock.
 370  */
 371 static inline void vlc_spin_lock (vlc_spinlock_t *spin)
 372 {
 373     EnterCriticalSection(spin);
 374 }
 375
 376 /**
 377  * Releases a spinlock.
 378  */
 379 static inline void vlc_spin_unlock (vlc_spinlock_t *spin)
 380 {
 381     LeaveCriticalSection(spin);
 382 }
 383
 384 /**
 385  * Deinitializes a spinlock.
 386  */
 387 static inline void vlc_spin_destroy (vlc_spinlock_t *spin)
 388 {
 389     DeleteCriticalSection(spin);
 390 }
 391
 392 #else
 393
 394 /* Fallback to plain mutexes if spinlocks are not available */
 395 typedef vlc_mutex_t vlc_spinlock_t;
 396
 397 static inline int vlc_spin_init (vlc_spinlock_t *spin)
 398 {
 399     return vlc_mutex_init (spin);
 400 }
 401
 402 # define vlc_spin_lock    vlc_mutex_lock
 403 # define vlc_spin_unlock  vlc_mutex_unlock
 404 # define vlc_spin_destroy vlc_mutex_destroy
 405 #endif
 406
 407 /**
 408  * Issues a full memory barrier.
 409  */
 410 #if defined (__APPLE__)
 411 # include <libkern/OSAtomic.h> /* OSMemoryBarrier() */
 412 #endif
 413 static inline void barrier (void)
 414 {
 415 #if defined (__GNUC__) && \
 416             ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1))
 417     __sync_synchronize ();
 418 #elif defined(__APPLE__)
 419     OSMemoryBarrier ();
 420 #elif defined(__powerpc__)
 421     asm volatile ("sync":::"memory");
 422 #elif 0 // defined(__i386__) /*  Requires SSE2 support */
 423     asm volatile ("mfence":::"memory");
 424 #else
 425     vlc_spinlock_t spin;
 426     vlc_spin_init (&spin);
 427     vlc_spin_lock (&spin);
 428     vlc_spin_unlock (&spin);
 429     vlc_spin_destroy (&spin);
 430 #endif
 431 }
 432
 433 /*****************************************************************************
 434  * vlc_thread_create: create a thread
 435  *****************************************************************************/
 436 #define vlc_thread_create( P_THIS, PSZ_NAME, FUNC, PRIORITY, WAIT )         \
 437     __vlc_thread_create( VLC_OBJECT(P_THIS), __FILE__, __LINE__, PSZ_NAME, FUNC, PRIORITY, WAIT )
 438
 439 /*****************************************************************************
 440  * vlc_thread_set_priority: set the priority of the calling thread
 441  *****************************************************************************/
 442 #define vlc_thread_set_priority( P_THIS, PRIORITY )                         \
 443     __vlc_thread_set_priority( VLC_OBJECT(P_THIS), __FILE__, __LINE__, PRIORITY )
 444
 445 /*****************************************************************************
 446  * vlc_thread_join: wait until a thread exits
 447  *****************************************************************************/
 448 #define vlc_thread_join( P_THIS )                                           \
 449     __vlc_thread_join( VLC_OBJECT(P_THIS) )
 450
 451 #endif /* !_VLC_THREADS_H */