src/third_party/ffmpeg/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 FFMPEG_COMPAT_W32PTHREADS_H
  30 #define FFMPEG_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 #include "libavutil/common.h"
  43 #include "libavutil/internal.h"
  44 #include "libavutil/mem.h"
  45
  46 typedef struct pthread_t {
  47     void *handle;
  48     void *(*func)(void* arg);
  49     void *arg;
  50     void *ret;
  51 } pthread_t;
  52
  53 /* the conditional variable api for windows 6.0+ uses critical sections and
  54  * not mutexes */
  55 typedef CRITICAL_SECTION pthread_mutex_t;
  56
  57 /* This is the CONDITIONAL_VARIABLE typedef for using Window's native
  58  * conditional variables on kernels 6.0+.
  59  * MinGW does not currently have this typedef. */
  60 typedef struct pthread_cond_t {
  61     void *ptr;
  62 } pthread_cond_t;
  63
  64 /* function pointers to conditional variable API on windows 6.0+ kernels */
  65 // TODO(dalecurtis): Upstream incorrectly assumes Vista+.  Reported.
  66 // #if _WIN32_WINNT < 0x0600
  67 static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
  68 static void (WINAPI *cond_init)(pthread_cond_t *cond);
  69 static void (WINAPI *cond_signal)(pthread_cond_t *cond);
  70 static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
  71                                 DWORD milliseconds);
  72 // #else
  73 // #define cond_init      InitializeConditionVariable
  74 // #define cond_broadcast WakeAllConditionVariable
  75 // #define cond_signal    WakeConditionVariable
  76 // #define cond_wait      SleepConditionVariableCS
  77 // #endif
  78
  79 static unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
  80 {
  81     pthread_t *h = arg;
  82     h->ret = h->func(h->arg);
  83     return 0;
  84 }
  85
  86 static int pthread_create(pthread_t *thread, const void *unused_attr,
  87                           void *(*start_routine)(void*), void *arg)
  88 {
  89     thread->func   = start_routine;
  90     thread->arg    = arg;
  91     thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
  92                                            0, NULL);
  93     return !thread->handle;
  94 }
  95
  96 static void pthread_join(pthread_t thread, void **value_ptr)
  97 {
  98     DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
  99     if (ret != WAIT_OBJECT_0)
 100         return;
 101     if (value_ptr)
 102         *value_ptr = thread.ret;
 103     CloseHandle(thread.handle);
 104 }
 105
 106 static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
 107 {
 108     InitializeCriticalSection(m);
 109     return 0;
 110 }
 111 static inline int pthread_mutex_destroy(pthread_mutex_t *m)
 112 {
 113     DeleteCriticalSection(m);
 114     return 0;
 115 }
 116 static inline int pthread_mutex_lock(pthread_mutex_t *m)
 117 {
 118     EnterCriticalSection(m);
 119     return 0;
 120 }
 121 static inline int pthread_mutex_unlock(pthread_mutex_t *m)
 122 {
 123     LeaveCriticalSection(m);
 124     return 0;
 125 }
 126
 127 /* for pre-Windows 6.0 platforms we need to define and use our own condition
 128  * variable and api */
 129 typedef struct  win32_cond_t {
 130     pthread_mutex_t mtx_broadcast;
 131     pthread_mutex_t mtx_waiter_count;
 132     volatile int waiter_count;
 133     HANDLE semaphore;
 134     HANDLE waiters_done;
 135     volatile int is_broadcast;
 136 } win32_cond_t;
 137
 138 static int pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
 139 {
 140     win32_cond_t *win32_cond = NULL;
 141     if (cond_init) {
 142         cond_init(cond);
 143         return 0;
 144     }
 145
 146     /* non native condition variables */
 147     win32_cond = av_mallocz(sizeof(win32_cond_t));
 148     if (!win32_cond)
 149         return ENOMEM;
 150     cond->ptr = win32_cond;
 151     win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
 152     if (!win32_cond->semaphore)
 153         return ENOMEM;
 154     win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
 155     if (!win32_cond->waiters_done)
 156         return ENOMEM;
 157
 158     pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
 159     pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
 160     return 0;
 161 }
 162
 163 static void pthread_cond_destroy(pthread_cond_t *cond)
 164 {
 165     win32_cond_t *win32_cond = cond->ptr;
 166     /* native condition variables do not destroy */
 167     if (cond_init)
 168         return;
 169
 170     /* non native condition variables */
 171     CloseHandle(win32_cond->semaphore);
 172     CloseHandle(win32_cond->waiters_done);
 173     pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
 174     pthread_mutex_destroy(&win32_cond->mtx_broadcast);
 175     av_freep(&win32_cond);
 176     cond->ptr = NULL;
 177 }
 178
 179 static void pthread_cond_broadcast(pthread_cond_t *cond)
 180 {
 181     win32_cond_t *win32_cond = cond->ptr;
 182     int have_waiter;
 183
 184     if (cond_broadcast) {
 185         cond_broadcast(cond);
 186         return;
 187     }
 188
 189     /* non native condition variables */
 190     pthread_mutex_lock(&win32_cond->mtx_broadcast);
 191     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
 192     have_waiter = 0;
 193
 194     if (win32_cond->waiter_count) {
 195         win32_cond->is_broadcast = 1;
 196         have_waiter = 1;
 197     }
 198
 199     if (have_waiter) {
 200         ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
 201         pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
 202         WaitForSingleObject(win32_cond->waiters_done, INFINITE);
 203         ResetEvent(win32_cond->waiters_done);
 204         win32_cond->is_broadcast = 0;
 205     } else
 206         pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
 207     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
 208 }
 209
 210 static int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
 211 {
 212     win32_cond_t *win32_cond = cond->ptr;
 213     int last_waiter;
 214     if (cond_wait) {
 215         cond_wait(cond, mutex, INFINITE);
 216         return 0;
 217     }
 218
 219     /* non native condition variables */
 220     pthread_mutex_lock(&win32_cond->mtx_broadcast);
 221     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
 222     win32_cond->waiter_count++;
 223     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
 224     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
 225
 226     // unlock the external mutex
 227     pthread_mutex_unlock(mutex);
 228     WaitForSingleObject(win32_cond->semaphore, INFINITE);
 229
 230     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
 231     win32_cond->waiter_count--;
 232     last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
 233     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
 234
 235     if (last_waiter)
 236         SetEvent(win32_cond->waiters_done);
 237
 238     // lock the external mutex
 239     return pthread_mutex_lock(mutex);
 240 }
 241
 242 static void pthread_cond_signal(pthread_cond_t *cond)
 243 {
 244     win32_cond_t *win32_cond = cond->ptr;
 245     int have_waiter;
 246     if (cond_signal) {
 247         cond_signal(cond);
 248         return;
 249     }
 250
 251     pthread_mutex_lock(&win32_cond->mtx_broadcast);
 252
 253     /* non-native condition variables */
 254     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
 255     have_waiter = win32_cond->waiter_count;
 256     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
 257
 258     if (have_waiter) {
 259         ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
 260         WaitForSingleObject(win32_cond->waiters_done, INFINITE);
 261         ResetEvent(win32_cond->waiters_done);
 262     }
 263
 264     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
 265 }
 266
 267 static void w32thread_init(void)
 268 {
 269     // TODO(dalecurtis): Upstream incorrectly assumes Vista+.  Reported.
 270 // #if _WIN32_WINNT < 0x0600
 271     HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
 272     /* if one is available, then they should all be available */
 273     cond_init      =
 274         (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
 275     cond_broadcast =
 276         (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
 277     cond_signal    =
 278         (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
 279     cond_wait      =
 280         (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
 281 // #else
 282 //     cond_init      = InitializeConditionVariable;
 283 //     cond_broadcast = WakeAllConditionVariable;
 284 //     cond_signal    = WakeConditionVariable;
 285 //     cond_wait      = SleepConditionVariableCS;
 286 // #endif
 287
 288 }
 289
 290 #endif /* FFMPEG_COMPAT_W32PTHREADS_H */