git.sesse.net Git - ffmpeg/blob - compat/w32pthreads.h

   1 /*
   2  * Copyright (C) 2010-2011 x264 project
   3  *
   4  * Authors: Steven Walters <kemuri9@gmail.com>
   5  *          Pegasys Inc. <http://www.pegasys-inc.com>
   6  *
   7  * This file is part of FFmpeg.
   8  *
   9  * FFmpeg is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * FFmpeg is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with FFmpeg; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 /**
  25  * @file
  26  * w32threads to pthreads wrapper
  27  */
  28
  29 #ifndef COMPAT_W32PTHREADS_H
  30 #define COMPAT_W32PTHREADS_H
  31
  32 /* Build up a pthread-like API using underlying Windows API. Have only static
  33  * methods so as to not conflict with a potentially linked in pthread-win32
  34  * library.
  35  * As most functions here are used without checking return values,
  36  * only implement return values as necessary. */
  37
  38 #define WIN32_LEAN_AND_MEAN
  39 #include <windows.h>
  40 #include <process.h>
  41
  42 #if _WIN32_WINNT < 0x0600 && defined(__MINGW32__)
  43 #undef MemoryBarrier
  44 #define MemoryBarrier __sync_synchronize
  45 #endif
  46
  47 #include "libavutil/attributes.h"
  48 #include "libavutil/common.h"
  49 #include "libavutil/internal.h"
  50 #include "libavutil/mem.h"
  51
  52 typedef struct pthread_t {
  53     void *handle;
  54     void *(*func)(void* arg);
  55     void *arg;
  56     void *ret;
  57 } pthread_t;
  58
  59 /* the conditional variable api for windows 6.0+ uses critical sections and
  60  * not mutexes */
  61 typedef CRITICAL_SECTION pthread_mutex_t;
  62
  63 /* This is the CONDITION_VARIABLE typedef for using Windows' native
  64  * conditional variables on kernels 6.0+. */
  65 #if HAVE_CONDITION_VARIABLE_PTR
  66 typedef CONDITION_VARIABLE pthread_cond_t;
  67 #else
  68 typedef struct pthread_cond_t {
  69     void *Ptr;
  70 } pthread_cond_t;
  71 #endif
  72
  73 #if _WIN32_WINNT >= 0x0600
  74 #define InitializeCriticalSection(x) InitializeCriticalSectionEx(x, 0, 0)
  75 #define WaitForSingleObject(a, b) WaitForSingleObjectEx(a, b, FALSE)
  76 #endif
  77
  78 static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
  79 {
  80     pthread_t *h = (pthread_t*)arg;
  81     h->ret = h->func(h->arg);
  82     return 0;
  83 }
  84
  85 static av_unused int pthread_create(pthread_t *thread, const void *unused_attr,
  86                                     void *(*start_routine)(void*), void *arg)
  87 {
  88     thread->func   = start_routine;
  89     thread->arg    = arg;
  90 #if HAVE_WINRT
  91     thread->handle = (void*)CreateThread(NULL, 0, win32thread_worker, thread,
  92                                            0, NULL);
  93 #else
  94     thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
  95                                            0, NULL);
  96 #endif
  97     return !thread->handle;
  98 }
  99
 100 static av_unused int pthread_join(pthread_t thread, void **value_ptr)
 101 {
 102     DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
 103     if (ret != WAIT_OBJECT_0) {
 104         if (ret == WAIT_ABANDONED)
 105             return EINVAL;
 106         else
 107             return EDEADLK;
 108     }
 109     if (value_ptr)
 110         *value_ptr = thread.ret;
 111     CloseHandle(thread.handle);
 112     return 0;
 113 }
 114
 115 static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
 116 {
 117     InitializeCriticalSection(m);
 118     return 0;
 119 }
 120 static inline int pthread_mutex_destroy(pthread_mutex_t *m)
 121 {
 122     DeleteCriticalSection(m);
 123     return 0;
 124 }
 125 static inline int pthread_mutex_lock(pthread_mutex_t *m)
 126 {
 127     EnterCriticalSection(m);
 128     return 0;
 129 }
 130 static inline int pthread_mutex_unlock(pthread_mutex_t *m)
 131 {
 132     LeaveCriticalSection(m);
 133     return 0;
 134 }
 135
 136 #if _WIN32_WINNT >= 0x0600
 137 typedef INIT_ONCE pthread_once_t;
 138 #define PTHREAD_ONCE_INIT INIT_ONCE_STATIC_INIT
 139
 140 static av_unused int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
 141 {
 142     BOOL pending = FALSE;
 143     InitOnceBeginInitialize(once_control, 0, &pending, NULL);
 144     if (pending)
 145         init_routine();
 146     InitOnceComplete(once_control, 0, NULL);
 147     return 0;
 148 }
 149
 150 static inline int pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
 151 {
 152     InitializeConditionVariable(cond);
 153     return 0;
 154 }
 155
 156 /* native condition variables do not destroy */
 157 static inline int pthread_cond_destroy(pthread_cond_t *cond)
 158 {
 159     return 0;
 160 }
 161
 162 static inline int pthread_cond_broadcast(pthread_cond_t *cond)
 163 {
 164     WakeAllConditionVariable(cond);
 165     return 0;
 166 }
 167
 168 static inline int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
 169 {
 170     SleepConditionVariableCS(cond, mutex, INFINITE);
 171     return 0;
 172 }
 173
 174 static inline int pthread_cond_signal(pthread_cond_t *cond)
 175 {
 176     WakeConditionVariable(cond);
 177     return 0;
 178 }
 179
 180 #else // _WIN32_WINNT < 0x0600
 181
 182 /* atomic init state of dynamically loaded functions */
 183 static LONG w32thread_init_state = 0;
 184 static av_unused void w32thread_init(void);
 185
 186 /* for pre-Windows 6.0 platforms, define INIT_ONCE struct,
 187  * compatible to the one used in the native API */
 188
 189 typedef union pthread_once_t  {
 190     void * Ptr;    ///< For the Windows 6.0+ native functions
 191     LONG state;    ///< For the pre-Windows 6.0 compat code
 192 } pthread_once_t;
 193
 194 #define PTHREAD_ONCE_INIT {0}
 195
 196 /* function pointers to init once API on windows 6.0+ kernels */
 197 static BOOL (WINAPI *initonce_begin)(pthread_once_t *lpInitOnce, DWORD dwFlags, BOOL *fPending, void **lpContext);
 198 static BOOL (WINAPI *initonce_complete)(pthread_once_t *lpInitOnce, DWORD dwFlags, void *lpContext);
 199
 200 /* pre-Windows 6.0 compat using a spin-lock */
 201 static inline void w32thread_once_fallback(LONG volatile *state, void (*init_routine)(void))
 202 {
 203     switch (InterlockedCompareExchange(state, 1, 0)) {
 204     /* Initial run */
 205     case 0:
 206         init_routine();
 207         InterlockedExchange(state, 2);
 208         break;
 209     /* Another thread is running init */
 210     case 1:
 211         while (1) {
 212             MemoryBarrier();
 213             if (*state == 2)
 214                 break;
 215             Sleep(0);
 216         }
 217         break;
 218     /* Initialization complete */
 219     case 2:
 220         break;
 221     }
 222 }
 223
 224 static av_unused int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
 225 {
 226     w32thread_once_fallback(&w32thread_init_state, w32thread_init);
 227
 228     /* Use native functions on Windows 6.0+ */
 229     if (initonce_begin && initonce_complete) {
 230         BOOL pending = FALSE;
 231         initonce_begin(once_control, 0, &pending, NULL);
 232         if (pending)
 233             init_routine();
 234         initonce_complete(once_control, 0, NULL);
 235         return 0;
 236     }
 237
 238     w32thread_once_fallback(&once_control->state, init_routine);
 239     return 0;
 240 }
 241
 242 /* for pre-Windows 6.0 platforms we need to define and use our own condition
 243  * variable and api */
 244
 245 typedef struct  win32_cond_t {
 246     pthread_mutex_t mtx_broadcast;
 247     pthread_mutex_t mtx_waiter_count;
 248     volatile int waiter_count;
 249     HANDLE semaphore;
 250     HANDLE waiters_done;
 251     volatile int is_broadcast;
 252 } win32_cond_t;
 253
 254 /* function pointers to conditional variable API on windows 6.0+ kernels */
 255 static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
 256 static void (WINAPI *cond_init)(pthread_cond_t *cond);
 257 static void (WINAPI *cond_signal)(pthread_cond_t *cond);
 258 static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
 259                                 DWORD milliseconds);
 260
 261 static av_unused int pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
 262 {
 263     win32_cond_t *win32_cond = NULL;
 264
 265     w32thread_once_fallback(&w32thread_init_state, w32thread_init);
 266
 267     if (cond_init) {
 268         cond_init(cond);
 269         return 0;
 270     }
 271
 272     /* non native condition variables */
 273     win32_cond = (win32_cond_t*)av_mallocz(sizeof(win32_cond_t));
 274     if (!win32_cond)
 275         return ENOMEM;
 276     cond->Ptr = win32_cond;
 277     win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
 278     if (!win32_cond->semaphore)
 279         return ENOMEM;
 280     win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
 281     if (!win32_cond->waiters_done)
 282         return ENOMEM;
 283
 284     pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
 285     pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
 286     return 0;
 287 }
 288
 289 static av_unused int pthread_cond_destroy(pthread_cond_t *cond)
 290 {
 291     win32_cond_t *win32_cond = (win32_cond_t*)cond->Ptr;
 292     /* native condition variables do not destroy */
 293     if (cond_init)
 294         return 0;
 295
 296     /* non native condition variables */
 297     CloseHandle(win32_cond->semaphore);
 298     CloseHandle(win32_cond->waiters_done);
 299     pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
 300     pthread_mutex_destroy(&win32_cond->mtx_broadcast);
 301     av_freep(&win32_cond);
 302     cond->Ptr = NULL;
 303     return 0;
 304 }
 305
 306 static av_unused int pthread_cond_broadcast(pthread_cond_t *cond)
 307 {
 308     win32_cond_t *win32_cond = (win32_cond_t*)cond->Ptr;
 309     int have_waiter;
 310
 311     if (cond_broadcast) {
 312         cond_broadcast(cond);
 313         return 0;
 314     }
 315
 316     /* non native condition variables */
 317     pthread_mutex_lock(&win32_cond->mtx_broadcast);
 318     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
 319     have_waiter = 0;
 320
 321     if (win32_cond->waiter_count) {
 322         win32_cond->is_broadcast = 1;
 323         have_waiter = 1;
 324     }
 325
 326     if (have_waiter) {
 327         ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
 328         pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
 329         WaitForSingleObject(win32_cond->waiters_done, INFINITE);
 330         ResetEvent(win32_cond->waiters_done);
 331         win32_cond->is_broadcast = 0;
 332     } else
 333         pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
 334     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
 335     return 0;
 336 }
 337
 338 static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
 339 {
 340     win32_cond_t *win32_cond = (win32_cond_t*)cond->Ptr;
 341     int last_waiter;
 342     if (cond_wait) {
 343         cond_wait(cond, mutex, INFINITE);
 344         return 0;
 345     }
 346
 347     /* non native condition variables */
 348     pthread_mutex_lock(&win32_cond->mtx_broadcast);
 349     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
 350     win32_cond->waiter_count++;
 351     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
 352     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
 353
 354     // unlock the external mutex
 355     pthread_mutex_unlock(mutex);
 356     WaitForSingleObject(win32_cond->semaphore, INFINITE);
 357
 358     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
 359     win32_cond->waiter_count--;
 360     last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
 361     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
 362
 363     if (last_waiter)
 364         SetEvent(win32_cond->waiters_done);
 365
 366     // lock the external mutex
 367     return pthread_mutex_lock(mutex);
 368 }
 369
 370 static av_unused int pthread_cond_signal(pthread_cond_t *cond)
 371 {
 372     win32_cond_t *win32_cond = (win32_cond_t*)cond->Ptr;
 373     int have_waiter;
 374     if (cond_signal) {
 375         cond_signal(cond);
 376         return 0;
 377     }
 378
 379     pthread_mutex_lock(&win32_cond->mtx_broadcast);
 380
 381     /* non-native condition variables */
 382     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
 383     have_waiter = win32_cond->waiter_count;
 384     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
 385
 386     if (have_waiter) {
 387         ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
 388         WaitForSingleObject(win32_cond->waiters_done, INFINITE);
 389         ResetEvent(win32_cond->waiters_done);
 390     }
 391
 392     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
 393     return 0;
 394 }
 395 #endif
 396
 397 static av_unused void w32thread_init(void)
 398 {
 399 #if _WIN32_WINNT < 0x0600
 400     HMODULE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
 401     /* if one is available, then they should all be available */
 402     cond_init      = (void (WINAPI*)(pthread_cond_t *))
 403         GetProcAddress(kernel_dll, "InitializeConditionVariable");
 404     cond_broadcast = (void (WINAPI*)(pthread_cond_t *))
 405         GetProcAddress(kernel_dll, "WakeAllConditionVariable");
 406     cond_signal    = (void (WINAPI*)(pthread_cond_t *))
 407         GetProcAddress(kernel_dll, "WakeConditionVariable");
 408     cond_wait      = (BOOL (WINAPI*)(pthread_cond_t *, pthread_mutex_t *, DWORD))
 409         GetProcAddress(kernel_dll, "SleepConditionVariableCS");
 410     initonce_begin = (BOOL (WINAPI*)(pthread_once_t *, DWORD, BOOL *, void **))
 411         GetProcAddress(kernel_dll, "InitOnceBeginInitialize");
 412     initonce_complete = (BOOL (WINAPI*)(pthread_once_t *, DWORD, void *))
 413         GetProcAddress(kernel_dll, "InitOnceComplete");
 414 #endif
 415
 416 }
 417
 418 #endif /* COMPAT_W32PTHREADS_H */