Libav
w32pthreads.h
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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 Libav.
8  *
9  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
29 #ifndef LIBAV_COMPAT_W32PTHREADS_H
30 #define LIBAV_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/internal.h"
49 #include "libavutil/mem.h"
50 
51 typedef struct pthread_t {
52  void *handle;
53  void *(*func)(void* arg);
54  void *arg;
55  void *ret;
56 } pthread_t;
57 
58 /* the conditional variable api for windows 6.0+ uses critical sections and
59  * not mutexes */
60 typedef CRITICAL_SECTION pthread_mutex_t;
61 
62 /* This is the CONDITION_VARIABLE typedef for using Windows' native
63  * conditional variables on kernels 6.0+. */
64 #if HAVE_CONDITION_VARIABLE_PTR
65 typedef CONDITION_VARIABLE pthread_cond_t;
66 #else
67 typedef struct pthread_cond_t {
68  void *Ptr;
70 #endif
71 
72 #if _WIN32_WINNT >= 0x0600
73 #define InitializeCriticalSection(x) InitializeCriticalSectionEx(x, 0, 0)
74 #define WaitForSingleObject(a, b) WaitForSingleObjectEx(a, b, FALSE)
75 #endif
76 
77 static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
78 {
79  pthread_t *h = arg;
80  h->ret = h->func(h->arg);
81  return 0;
82 }
83 
84 static av_unused int pthread_create(pthread_t *thread, const void *unused_attr,
85  void *(*start_routine)(void*), void *arg)
86 {
87  thread->func = start_routine;
88  thread->arg = arg;
89  thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
90  0, NULL);
91  return !thread->handle;
92 }
93 
94 static av_unused void pthread_join(pthread_t thread, void **value_ptr)
95 {
96  DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
97  if (ret != WAIT_OBJECT_0)
98  return;
99  if (value_ptr)
100  *value_ptr = thread.ret;
101  CloseHandle(thread.handle);
102 }
103 
104 static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
105 {
106  InitializeCriticalSection(m);
107  return 0;
108 }
110 {
111  DeleteCriticalSection(m);
112  return 0;
113 }
114 static inline int pthread_mutex_lock(pthread_mutex_t *m)
115 {
116  EnterCriticalSection(m);
117  return 0;
118 }
120 {
121  LeaveCriticalSection(m);
122  return 0;
123 }
124 
125 #if _WIN32_WINNT >= 0x0600
126 
127 typedef INIT_ONCE pthread_once_t;
128 #define PTHREAD_ONCE_INIT INIT_ONCE_STATIC_INIT
129 
130 static av_unused int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
131 {
132  BOOL pending = FALSE;
133  InitOnceBeginInitialize(once_control, 0, &pending, NULL);
134  if (pending)
135  init_routine();
136  InitOnceComplete(once_control, 0, NULL);
137  return 0;
138 }
139 
140 static inline void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
141 {
142  InitializeConditionVariable(cond);
143 }
144 
145 /* native condition variables do not destroy */
146 static inline void pthread_cond_destroy(pthread_cond_t *cond)
147 {
148  return;
149 }
150 
151 static inline void pthread_cond_broadcast(pthread_cond_t *cond)
152 {
153  WakeAllConditionVariable(cond);
154 }
155 
156 static inline int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
157 {
158  SleepConditionVariableCS(cond, mutex, INFINITE);
159  return 0;
160 }
161 
162 static inline void pthread_cond_signal(pthread_cond_t *cond)
163 {
164  WakeConditionVariable(cond);
165 }
166 
167 #else // _WIN32_WINNT < 0x0600
168 
169 /* atomic init state of dynamically loaded functions */
170 static LONG w32thread_init_state = 0;
171 static av_unused void w32thread_init(void);
172 
173 /* for pre-Windows 6.0 platforms, define INIT_ONCE struct,
174  * compatible to the one used in the native API */
175 
176 typedef union pthread_once_t {
177  void * Ptr;
178  LONG state;
179 } pthread_once_t;
180 
181 #define PTHREAD_ONCE_INIT {0}
182 
183 /* function pointers to init once API on windows 6.0+ kernels */
184 static BOOL (WINAPI *initonce_begin)(pthread_once_t *lpInitOnce, DWORD dwFlags, BOOL *fPending, void **lpContext);
185 static BOOL (WINAPI *initonce_complete)(pthread_once_t *lpInitOnce, DWORD dwFlags, void *lpContext);
186 
187 /* pre-Windows 6.0 compat using a spin-lock */
188 static inline void w32thread_once_fallback(LONG volatile *state, void (*init_routine)(void))
189 {
190  switch (InterlockedCompareExchange(state, 1, 0)) {
191  /* Initial run */
192  case 0:
193  init_routine();
194  InterlockedExchange(state, 2);
195  break;
196  /* Another thread is running init */
197  case 1:
198  while (1) {
199  MemoryBarrier();
200  if (*state == 2)
201  break;
202  Sleep(0);
203  }
204  break;
205  /* Initialization complete */
206  case 2:
207  break;
208  }
209 }
210 
211 static av_unused int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
212 {
213  w32thread_once_fallback(&w32thread_init_state, w32thread_init);
214 
215  /* Use native functions on Windows 6.0+ */
216  if (initonce_begin && initonce_complete) {
217  BOOL pending = FALSE;
218  initonce_begin(once_control, 0, &pending, NULL);
219  if (pending)
220  init_routine();
221  initonce_complete(once_control, 0, NULL);
222  return 0;
223  }
224 
225  w32thread_once_fallback(&once_control->state, init_routine);
226  return 0;
227 }
228 
229 /* for pre-Windows 6.0 platforms we need to define and use our own condition
230  * variable and api */
231 
232 typedef struct win32_cond_t {
235  volatile int waiter_count;
236  HANDLE semaphore;
237  HANDLE waiters_done;
238  volatile int is_broadcast;
239 } win32_cond_t;
240 
241 /* function pointers to conditional variable API on windows 6.0+ kernels */
242 static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
243 static void (WINAPI *cond_init)(pthread_cond_t *cond);
244 static void (WINAPI *cond_signal)(pthread_cond_t *cond);
245 static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
246  DWORD milliseconds);
247 
248 static av_unused void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
249 {
250  win32_cond_t *win32_cond = NULL;
251 
252  w32thread_once_fallback(&w32thread_init_state, w32thread_init);
253 
254  if (cond_init) {
255  cond_init(cond);
256  return;
257  }
258 
259  /* non native condition variables */
260  win32_cond = av_mallocz(sizeof(win32_cond_t));
261  if (!win32_cond)
262  return;
263  cond->Ptr = win32_cond;
264  win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
265  if (!win32_cond->semaphore)
266  return;
267  win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
268  if (!win32_cond->waiters_done)
269  return;
270 
272  pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
273 }
274 
276 {
277  win32_cond_t *win32_cond = cond->Ptr;
278  /* native condition variables do not destroy */
279  if (cond_init)
280  return;
281 
282  /* non native condition variables */
283  CloseHandle(win32_cond->semaphore);
284  CloseHandle(win32_cond->waiters_done);
286  pthread_mutex_destroy(&win32_cond->mtx_broadcast);
287  av_freep(&win32_cond);
288  cond->Ptr = NULL;
289 }
290 
292 {
293  win32_cond_t *win32_cond = cond->Ptr;
294  int have_waiter;
295 
296  if (cond_broadcast) {
297  cond_broadcast(cond);
298  return;
299  }
300 
301  /* non native condition variables */
302  pthread_mutex_lock(&win32_cond->mtx_broadcast);
303  pthread_mutex_lock(&win32_cond->mtx_waiter_count);
304  have_waiter = 0;
305 
306  if (win32_cond->waiter_count) {
307  win32_cond->is_broadcast = 1;
308  have_waiter = 1;
309  }
310 
311  if (have_waiter) {
312  ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
314  WaitForSingleObject(win32_cond->waiters_done, INFINITE);
315  ResetEvent(win32_cond->waiters_done);
316  win32_cond->is_broadcast = 0;
317  } else
319  pthread_mutex_unlock(&win32_cond->mtx_broadcast);
320 }
321 
323 {
324  win32_cond_t *win32_cond = cond->Ptr;
325  int last_waiter;
326  if (cond_wait) {
327  cond_wait(cond, mutex, INFINITE);
328  return 0;
329  }
330 
331  /* non native condition variables */
332  pthread_mutex_lock(&win32_cond->mtx_broadcast);
333  pthread_mutex_lock(&win32_cond->mtx_waiter_count);
334  win32_cond->waiter_count++;
336  pthread_mutex_unlock(&win32_cond->mtx_broadcast);
337 
338  // unlock the external mutex
339  pthread_mutex_unlock(mutex);
340  WaitForSingleObject(win32_cond->semaphore, INFINITE);
341 
342  pthread_mutex_lock(&win32_cond->mtx_waiter_count);
343  win32_cond->waiter_count--;
344  last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
346 
347  if (last_waiter)
348  SetEvent(win32_cond->waiters_done);
349 
350  // lock the external mutex
351  return pthread_mutex_lock(mutex);
352 }
353 
355 {
356  win32_cond_t *win32_cond = cond->Ptr;
357  int have_waiter;
358  if (cond_signal) {
359  cond_signal(cond);
360  return;
361  }
362 
363  pthread_mutex_lock(&win32_cond->mtx_broadcast);
364 
365  /* non-native condition variables */
366  pthread_mutex_lock(&win32_cond->mtx_waiter_count);
367  have_waiter = win32_cond->waiter_count;
369 
370  if (have_waiter) {
371  ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
372  WaitForSingleObject(win32_cond->waiters_done, INFINITE);
373  ResetEvent(win32_cond->waiters_done);
374  }
375 
376  pthread_mutex_unlock(&win32_cond->mtx_broadcast);
377 }
378 #endif
379 
380 static av_unused void w32thread_init(void)
381 {
382 #if _WIN32_WINNT < 0x0600
383  HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
384  /* if one is available, then they should all be available */
385  cond_init =
386  (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
387  cond_broadcast =
388  (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
389  cond_signal =
390  (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
391  cond_wait =
392  (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
393  initonce_begin =
394  (void*)GetProcAddress(kernel_dll, "InitOnceBeginInitialize");
395  initonce_complete =
396  (void*)GetProcAddress(kernel_dll, "InitOnceComplete");
397 #endif
398 
399 }
400 
401 #endif /* LIBAV_COMPAT_W32PTHREADS_H */
static av_unused void pthread_cond_signal(pthread_cond_t *cond)
Definition: w32pthreads.h:354
static BOOL(WINAPI *initonce_begin)(pthread_once_t *lpInitOnce
static av_unused void w32thread_init(void)
Definition: w32pthreads.h:380
volatile int is_broadcast
Definition: w32pthreads.h:238
static av_unused void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
Definition: w32pthreads.h:248
static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
Definition: w32pthreads.h:77
memory handling functions
static av_unused void pthread_cond_broadcast(pthread_cond_t *cond)
Definition: w32pthreads.h:291
void * arg
Definition: w32pthreads.h:54
volatile int waiter_count
Definition: w32pthreads.h:235
Macro definitions for various function/variable attributes.
void av_freep(void *arg)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:202
static pthread_mutex_t DWORD milliseconds
Definition: w32pthreads.h:245
static DWORD BOOL * fPending
Definition: w32pthreads.h:184
static void w32thread_once_fallback(LONG volatile *state, void(*init_routine)(void))
Definition: w32pthreads.h:188
CRITICAL_SECTION pthread_mutex_t
Definition: w32pthreads.h:60
void * Ptr
For the Windows 6.0+ native functions.
Definition: w32pthreads.h:177
static av_unused int pthread_create(pthread_t *thread, const void *unused_attr, void *(*start_routine)(void *), void *arg)
Definition: w32pthreads.h:84
void * ret
Definition: w32pthreads.h:55
HANDLE waiters_done
Definition: w32pthreads.h:237
static int pthread_mutex_init(pthread_mutex_t *m, void *attr)
Definition: w32pthreads.h:104
static int pthread_mutex_unlock(pthread_mutex_t *m)
Definition: w32pthreads.h:119
static DWORD BOOL void ** lpContext
Definition: w32pthreads.h:184
static av_unused void pthread_join(pthread_t thread, void **value_ptr)
Definition: w32pthreads.h:94
common internal API header
static int pthread_mutex_destroy(pthread_mutex_t *m)
Definition: w32pthreads.h:109
static av_unused void pthread_cond_destroy(pthread_cond_t *cond)
Definition: w32pthreads.h:275
static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
Definition: w32pthreads.h:322
void *(* func)(void *arg)
Definition: w32pthreads.h:53
HANDLE semaphore
Definition: w32pthreads.h:236
static pthread_mutex_t * mutex
Definition: w32pthreads.h:245
pthread_mutex_t mtx_broadcast
Definition: w32pthreads.h:233
static DWORD dwFlags
Definition: w32pthreads.h:184
#define attribute_align_arg
Definition: internal.h:55
NULL
Definition: eval.c:55
static int pthread_mutex_lock(pthread_mutex_t *m)
Definition: w32pthreads.h:114
static void(WINAPI *cond_broadcast)(pthread_cond_t *cond)
static LONG w32thread_init_state
Definition: w32pthreads.h:170
static av_unused int pthread_once(pthread_once_t *once_control, void(*init_routine)(void))
Definition: w32pthreads.h:211
LONG state
For the pre-Windows 6.0 compat code.
Definition: w32pthreads.h:178
static struct @174 state
#define GetProcAddress
Definition: avisynth.c:45
void * handle
Definition: w32pthreads.h:52
pthread_mutex_t mtx_waiter_count
Definition: w32pthreads.h:234
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:211
#define av_unused
Definition: attributes.h:86