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 #if defined( UNDER_CE )
 119     HANDLE cancel_event;
 120 #endif
 121 } *vlc_thread_t;
 122
 123 typedef struct
 124 {
 125     LONG initialized;
 126     CRITICAL_SECTION mutex;
 127 } vlc_mutex_t;
 128 #define VLC_STATIC_MUTEX { 0, }
 129
 130 typedef HANDLE  vlc_cond_t;
 131 typedef DWORD   vlc_threadvar_t;
 132
 133 #endif
 134
 135 #if defined( WIN32 ) && !defined ETIMEDOUT
 136 #  define ETIMEDOUT 10060 /* This is the value in winsock.h. */
 137 #endif
 138
 139 /*****************************************************************************
 140  * Function definitions
 141  *****************************************************************************/
 142 VLC_EXPORT( int,  vlc_mutex_init,    ( vlc_mutex_t * ) );
 143 VLC_EXPORT( int,  vlc_mutex_init_recursive, ( vlc_mutex_t * ) );
 144 VLC_EXPORT( void, vlc_mutex_destroy, ( vlc_mutex_t * ) );
 145 VLC_EXPORT( void, vlc_mutex_lock, ( vlc_mutex_t * ) );
 146 VLC_EXPORT( int, vlc_mutex_trylock, ( vlc_mutex_t * ) );
 147 VLC_EXPORT( void, vlc_mutex_unlock, ( vlc_mutex_t * ) );
 148 VLC_EXPORT( int,  vlc_cond_init,     ( vlc_cond_t * ) );
 149 VLC_EXPORT( void, vlc_cond_destroy,  ( vlc_cond_t * ) );
 150 VLC_EXPORT( void, vlc_cond_signal, (vlc_cond_t *) );
 151 VLC_EXPORT( void, vlc_cond_broadcast, (vlc_cond_t *) );
 152 VLC_EXPORT( void, vlc_cond_wait, (vlc_cond_t *, vlc_mutex_t *) );
 153 VLC_EXPORT( int, vlc_cond_timedwait, (vlc_cond_t *, vlc_mutex_t *, mtime_t) );
 154 VLC_EXPORT( int, vlc_threadvar_create, (vlc_threadvar_t * , void (*) (void *) ) );
 155 VLC_EXPORT( void, vlc_threadvar_delete, (vlc_threadvar_t *) );
 156 VLC_EXPORT( int,  vlc_thread_create, ( vlc_object_t *, const char *, int, const char *, void * ( * ) ( vlc_object_t * ), int ) );
 157 VLC_EXPORT( int,  __vlc_thread_set_priority, ( vlc_object_t *, const char *, int, int ) );
 158 VLC_EXPORT( void, __vlc_thread_join,   ( vlc_object_t * ) );
 159
 160 VLC_EXPORT( int, vlc_clone, (vlc_thread_t *, void * (*) (void *), void *, int) );
 161 VLC_EXPORT( void, vlc_cancel, (vlc_thread_t) );
 162 VLC_EXPORT( void, vlc_join, (vlc_thread_t, void **) );
 163 VLC_EXPORT (void, vlc_control_cancel, (int cmd, ...));
 164
 165 #ifndef LIBVLC_USE_PTHREAD_CANCEL
 166 enum {
 167     VLC_DO_CANCEL,
 168     VLC_CLEANUP_PUSH,
 169     VLC_CLEANUP_POP,
 170 };
 171 #endif
 172
 173 VLC_EXPORT( int, vlc_savecancel, (void) );
 174 VLC_EXPORT( void, vlc_restorecancel, (int state) );
 175 VLC_EXPORT( void, vlc_testcancel, (void) );
 176
 177 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
 178 /**
 179  * Registers a new procedure to run if the thread is cancelled (or otherwise
 180  * exits prematurely). Any call to vlc_cleanup_push() <b>must</b> paired with a
 181  * call to either vlc_cleanup_pop() or vlc_cleanup_run(). Branching into or out
 182  * of the block between these two function calls is not allowed (read: it will
 183  * likely crash the whole process). If multiple procedures are registered,
 184  * they are handled in last-in first-out order.
 185  *
 186  * @param routine procedure to call if the thread ends
 187  * @param arg argument for the procedure
 188  */
 189 # define vlc_cleanup_push( routine, arg ) pthread_cleanup_push (routine, arg)
 190
 191 /**
 192  * Removes a cleanup procedure that was previously registered with
 193  * vlc_cleanup_push().
 194  */
 195 # define vlc_cleanup_pop( ) pthread_cleanup_pop (0)
 196
 197 /**
 198  * Removes a cleanup procedure that was previously registered with
 199  * vlc_cleanup_push(), and executes it.
 200  */
 201 # define vlc_cleanup_run( ) pthread_cleanup_pop (1)
 202 #else
 203 typedef struct vlc_cleanup_t vlc_cleanup_t;
 204
 205 struct vlc_cleanup_t
 206 {
 207     vlc_cleanup_t *next;
 208     void         (*proc) (void *);
 209     void          *data;
 210 };
 211
 212 /* This macros opens a code block on purpose. This is needed for multiple
 213  * calls within a single function. This also prevent Win32 developpers from
 214  * writing code that would break on POSIX (POSIX opens a block as well). */
 215 # define vlc_cleanup_push( routine, arg ) \
 216     do { \
 217         vlc_cleanup_t vlc_cleanup_data = { NULL, routine, arg, }; \
 218         vlc_control_cancel (VLC_CLEANUP_PUSH, &vlc_cleanup_data)
 219
 220 # define vlc_cleanup_pop( ) \
 221         vlc_control_cancel (VLC_CLEANUP_POP); \
 222     } while (0)
 223
 224 # define vlc_cleanup_run( ) \
 225         vlc_control_cancel (VLC_CLEANUP_POP); \
 226         vlc_cleanup_data.proc (vlc_cleanup_data.data); \
 227     } while (0)
 228
 229 #endif /* LIBVLC_USE_PTHREAD_CANCEL */
 230
 231 static inline void vlc_cleanup_lock (void *lock)
 232 {
 233     vlc_mutex_unlock ((vlc_mutex_t *)lock);
 234 }
 235 #define mutex_cleanup_push( lock ) vlc_cleanup_push (vlc_cleanup_lock, lock)
 236
 237 /*****************************************************************************
 238  * vlc_threadvar_set: create: set the value of a thread-local variable
 239  *****************************************************************************/
 240 static inline int vlc_threadvar_set( vlc_threadvar_t * p_tls, void *p_value )
 241 {
 242     int i_ret;
 243
 244 #if defined(LIBVLC_USE_PTHREAD)
 245     i_ret = pthread_setspecific( *p_tls, p_value );
 246
 247 #elif defined( UNDER_CE ) || defined( WIN32 )
 248     i_ret = TlsSetValue( *p_tls, p_value ) ? EINVAL : 0;
 249
 250 #endif
 251
 252     return i_ret;
 253 }
 254
 255 /*****************************************************************************
 256  * vlc_threadvar_get: create: get the value of a thread-local variable
 257  *****************************************************************************/
 258 static inline void* vlc_threadvar_get( vlc_threadvar_t * p_tls )
 259 {
 260     void *p_ret;
 261
 262 #if defined(LIBVLC_USE_PTHREAD)
 263     p_ret = pthread_getspecific( *p_tls );
 264
 265 #elif defined( UNDER_CE ) || defined( WIN32 )
 266     p_ret = TlsGetValue( *p_tls );
 267
 268 #endif
 269
 270     return p_ret;
 271 }
 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 int vlc_spin_init (vlc_spinlock_t *spin)
 280 {
 281     return pthread_spin_init (spin, PTHREAD_PROCESS_PRIVATE);
 282 }
 283
 284 /**
 285  * Acquires a spinlock.
 286  */
 287 static inline void vlc_spin_lock (vlc_spinlock_t *spin)
 288 {
 289     pthread_spin_lock (spin);
 290 }
 291
 292 /**
 293  * Releases a spinlock.
 294  */
 295 static inline void vlc_spin_unlock (vlc_spinlock_t *spin)
 296 {
 297     pthread_spin_unlock (spin);
 298 }
 299
 300 /**
 301  * Deinitializes a spinlock.
 302  */
 303 static inline void vlc_spin_destroy (vlc_spinlock_t *spin)
 304 {
 305     pthread_spin_destroy (spin);
 306 }
 307
 308 #elif defined( WIN32 )
 309
 310 typedef CRITICAL_SECTION vlc_spinlock_t;
 311
 312 /**
 313  * Initializes a spinlock.
 314  */
 315 static inline int vlc_spin_init (vlc_spinlock_t *spin)
 316 {
 317 #ifdef UNDER_CE
 318     InitializeCriticalSection(spin);
 319     return 0;
 320 #else
 321     return !InitializeCriticalSectionAndSpinCount(spin, 4000);
 322 #endif
 323 }
 324
 325 /**
 326  * Acquires a spinlock.
 327  */
 328 static inline void vlc_spin_lock (vlc_spinlock_t *spin)
 329 {
 330     EnterCriticalSection(spin);
 331 }
 332
 333 /**
 334  * Releases a spinlock.
 335  */
 336 static inline void vlc_spin_unlock (vlc_spinlock_t *spin)
 337 {
 338     LeaveCriticalSection(spin);
 339 }
 340
 341 /**
 342  * Deinitializes a spinlock.
 343  */
 344 static inline void vlc_spin_destroy (vlc_spinlock_t *spin)
 345 {
 346     DeleteCriticalSection(spin);
 347 }
 348
 349 #else
 350
 351 /* Fallback to plain mutexes if spinlocks are not available */
 352 typedef vlc_mutex_t vlc_spinlock_t;
 353
 354 static inline int vlc_spin_init (vlc_spinlock_t *spin)
 355 {
 356     return vlc_mutex_init (spin);
 357 }
 358
 359 # define vlc_spin_lock    vlc_mutex_lock
 360 # define vlc_spin_unlock  vlc_mutex_unlock
 361 # define vlc_spin_destroy vlc_mutex_destroy
 362 #endif
 363
 364 /**
 365  * Issues a full memory barrier.
 366  */
 367 #if defined (__APPLE__)
 368 # include <libkern/OSAtomic.h> /* OSMemoryBarrier() */
 369 #endif
 370 static inline void barrier (void)
 371 {
 372 #if defined (__GNUC__) && \
 373             ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1))
 374     __sync_synchronize ();
 375 #elif defined(__APPLE__)
 376     OSMemoryBarrier ();
 377 #elif defined(__powerpc__)
 378     asm volatile ("sync":::"memory");
 379 #elif 0 // defined(__i386__) /*  Requires SSE2 support */
 380     asm volatile ("mfence":::"memory");
 381 #else
 382     vlc_spinlock_t spin;
 383     vlc_spin_init (&spin);
 384     vlc_spin_lock (&spin);
 385     vlc_spin_unlock (&spin);
 386     vlc_spin_destroy (&spin);
 387 #endif
 388 }
 389
 390 /*****************************************************************************
 391  * vlc_thread_create: create a thread
 392  *****************************************************************************/
 393 #define vlc_thread_create( P_THIS, PSZ_NAME, FUNC, PRIORITY )         \
 394     vlc_thread_create( VLC_OBJECT(P_THIS), __FILE__, __LINE__, PSZ_NAME, FUNC, PRIORITY )
 395
 396 /*****************************************************************************
 397  * vlc_thread_set_priority: set the priority of the calling thread
 398  *****************************************************************************/
 399 #define vlc_thread_set_priority( P_THIS, PRIORITY )                         \
 400     __vlc_thread_set_priority( VLC_OBJECT(P_THIS), __FILE__, __LINE__, PRIORITY )
 401
 402 /*****************************************************************************
 403  * vlc_thread_join: wait until a thread exits
 404  *****************************************************************************/
 405 #define vlc_thread_join( P_THIS )                                           \
 406     __vlc_thread_join( VLC_OBJECT(P_THIS) )
 407
 408 #ifdef __cplusplus
 409 /**
 410  * Helper C++ class to lock a mutex.
 411  * The mutex is locked when the object is created, and unlocked when the object
 412  * is destroyed.
 413  */
 414 class vlc_mutex_locker
 415 {
 416     private:
 417         vlc_mutex_t *lock;
 418     public:
 419         vlc_mutex_locker (vlc_mutex_t *m) : lock (m)
 420         {
 421             vlc_mutex_lock (lock);
 422         }
 423
 424         ~vlc_mutex_locker (void)
 425         {
 426             vlc_mutex_unlock (lock);
 427         }
 428 };
 429 #endif
 430
 431 #endif /* !_VLC_THREADS_H */