FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
w32pthreads.h
Go to the documentation of this file.
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;
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 = 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 }
121 {
122  DeleteCriticalSection(m);
123  return 0;
124 }
126 {
127  EnterCriticalSection(m);
128  return 0;
129 }
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 */
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 {
248  volatile int waiter_count;
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,
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 = 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 
285  pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
286  return 0;
287 }
288 
290 {
291  win32_cond_t *win32_cond = 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);
300  pthread_mutex_destroy(&win32_cond->mtx_broadcast);
301  av_freep(&win32_cond);
302  cond->Ptr = NULL;
303  return 0;
304 }
305 
307 {
308  win32_cond_t *win32_cond = 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);
329  WaitForSingleObject(win32_cond->waiters_done, INFINITE);
330  ResetEvent(win32_cond->waiters_done);
331  win32_cond->is_broadcast = 0;
332  } else
334  pthread_mutex_unlock(&win32_cond->mtx_broadcast);
335  return 0;
336 }
337 
339 {
340  win32_cond_t *win32_cond = 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++;
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;
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 
371 {
372  win32_cond_t *win32_cond = 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;
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  HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
401  /* if one is available, then they should all be available */
402  cond_init =
403  (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
404  cond_broadcast =
405  (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
406  cond_signal =
407  (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
408  cond_wait =
409  (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
410  initonce_begin =
411  (void*)GetProcAddress(kernel_dll, "InitOnceBeginInitialize");
412  initonce_complete =
413  (void*)GetProcAddress(kernel_dll, "InitOnceComplete");
414 #endif
415 
416 }
417 
418 #endif /* COMPAT_W32PTHREADS_H */
static BOOL(WINAPI *initonce_begin)(pthread_once_t *lpInitOnce
static av_unused void w32thread_init(void)
Definition: w32pthreads.h:397
uint32_t BOOL
#define NULL
Definition: coverity.c:32
volatile int is_broadcast
Definition: w32pthreads.h:251
static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
Definition: w32pthreads.h:78
memory handling functions
static av_unused int pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
Definition: w32pthreads.h:261
LONG state
For the pre-Windows 6.0 compat code.
Definition: w32pthreads.h:191
static av_unused int pthread_cond_destroy(pthread_cond_t *cond)
Definition: w32pthreads.h:289
volatile int waiter_count
Definition: w32pthreads.h:248
Macro definitions for various function/variable attributes.
static pthread_mutex_t DWORD milliseconds
Definition: w32pthreads.h:258
static DWORD BOOL * fPending
Definition: w32pthreads.h:197
HMTX pthread_mutex_t
Definition: os2threads.h:49
static void w32thread_once_fallback(LONG volatile *state, void(*init_routine)(void))
Definition: w32pthreads.h:201
CRITICAL_SECTION pthread_mutex_t
Definition: w32pthreads.h:61
static av_unused int pthread_create(pthread_t *thread, const void *unused_attr, void *(*start_routine)(void *), void *arg)
Definition: w32pthreads.h:85
void * ret
Definition: w32pthreads.h:56
HANDLE waiters_done
Definition: w32pthreads.h:250
unsigned m
Definition: audioconvert.c:187
void * arg
Definition: os2threads.h:43
static int pthread_mutex_init(pthread_mutex_t *m, void *attr)
Definition: w32pthreads.h:115
#define FALSE
Definition: windows2linux.h:37
void *(* func)(void *arg)
Definition: w32pthreads.h:54
static int pthread_mutex_unlock(pthread_mutex_t *m)
Definition: w32pthreads.h:130
const char * arg
Definition: jacosubdec.c:66
static DWORD BOOL void ** lpContext
Definition: w32pthreads.h:197
common internal API header
static int pthread_mutex_destroy(pthread_mutex_t *m)
Definition: w32pthreads.h:120
static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
Definition: w32pthreads.h:338
PVOID HANDLE
#define TRUE
Definition: windows2linux.h:33
HANDLE semaphore
Definition: w32pthreads.h:249
int32_t LONG
static pthread_mutex_t * mutex
Definition: w32pthreads.h:258
pthread_mutex_t mtx_broadcast
Definition: w32pthreads.h:246
static av_unused int pthread_cond_broadcast(pthread_cond_t *cond)
Definition: w32pthreads.h:306
static DWORD dwFlags
Definition: w32pthreads.h:197
static int pthread_mutex_lock(pthread_mutex_t *m)
Definition: w32pthreads.h:125
static void(WINAPI *cond_broadcast)(pthread_cond_t *cond)
static LONG w32thread_init_state
Definition: w32pthreads.h:183
uint32_t DWORD
static av_unused int pthread_once(pthread_once_t *once_control, void(*init_routine)(void))
Definition: w32pthreads.h:224
#define __stdcall
Definition: windows2linux.h:21
static av_unused int pthread_join(pthread_t thread, void **value_ptr)
Definition: w32pthreads.h:100
common internal and external API header
#define GetProcAddress
Definition: avisynth.c:44
void * handle
Definition: w32pthreads.h:53
pthread_mutex_t mtx_waiter_count
Definition: w32pthreads.h:247
#define av_freep(p)
void * Ptr
For the Windows 6.0+ native functions.
Definition: w32pthreads.h:190
static struct @230 state
static av_unused int pthread_cond_signal(pthread_cond_t *cond)
Definition: w32pthreads.h:370
#define InterlockedCompareExchange(x, y, z)
Definition: windows2linux.h:65
void * av_mallocz(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:252
#define av_unused
Definition: attributes.h:126