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1 /*
2  * Copyright (c) 2016, Alliance for Open Media. All rights reserved
3  *
4  * This source code is subject to the terms of the BSD 2 Clause License and
5  * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
6  * was not distributed with this source code in the LICENSE file, you can
7  * obtain it at www.aomedia.org/license/software. If the Alliance for Open
8  * Media Patent License 1.0 was not distributed with this source code in the
9  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
10  */
11 //
12 // Multi-threaded worker
13 //
14 // Original source:
15 //  https://chromium.googlesource.com/webm/libwebp
16 
17 #ifndef AOM_AOM_UTIL_AOM_THREAD_H_
18 #define AOM_AOM_UTIL_AOM_THREAD_H_
19 
20 #include "config/aom_config.h"
21 
22 #ifdef __cplusplus
23 extern "C" {
24 #endif
25 
26 // Set maximum decode threads to be 8 due to the limit of frame buffers
27 // and not enough semaphores in the emulation layer on windows.
28 #define MAX_DECODE_THREADS 8
29 #define MAX_NUM_THREADS 64
30 
31 #if CONFIG_MULTITHREAD
32 
33 #if defined(_WIN32) && !HAVE_PTHREAD_H
34 #include <errno.h>    // NOLINT
35 #include <process.h>  // NOLINT
36 #include <windows.h>  // NOLINT
37 typedef HANDLE pthread_t;
38 typedef CRITICAL_SECTION pthread_mutex_t;
39 
40 #if _WIN32_WINNT >= 0x0600  // Windows Vista / Server 2008 or greater
41 #define USE_WINDOWS_CONDITION_VARIABLE
42 typedef CONDITION_VARIABLE pthread_cond_t;
43 #else
44 typedef struct {
45   HANDLE waiting_sem_;
46   HANDLE received_sem_;
47   HANDLE signal_event_;
48 } pthread_cond_t;
49 #endif  // _WIN32_WINNT >= 0x600
50 
51 #ifndef WINAPI_FAMILY_PARTITION
52 #define WINAPI_PARTITION_DESKTOP 1
53 #define WINAPI_FAMILY_PARTITION(x) x
54 #endif
55 
56 #if !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
57 #define USE_CREATE_THREAD
58 #endif
59 
60 //------------------------------------------------------------------------------
61 // simplistic pthread emulation layer
62 
63 // _beginthreadex requires __stdcall
64 #define THREADFN unsigned int __stdcall
65 #define THREAD_RETURN(val) (unsigned int)((DWORD_PTR)val)
66 
67 #if _WIN32_WINNT >= 0x0501  // Windows XP or greater
68 #define WaitForSingleObject(obj, timeout) \
69   WaitForSingleObjectEx(obj, timeout, FALSE /*bAlertable*/)
70 #endif
71 
pthread_create(pthread_t * const thread,const void * attr,unsigned int (__stdcall * start)(void *),void * arg)72 static INLINE int pthread_create(pthread_t *const thread, const void *attr,
73                                  unsigned int(__stdcall *start)(void *),
74                                  void *arg) {
75   (void)attr;
76 #ifdef USE_CREATE_THREAD
77   *thread = CreateThread(NULL,          /* lpThreadAttributes */
78                          0,             /* dwStackSize */
79                          start, arg, 0, /* dwStackSize */
80                          NULL);         /* lpThreadId */
81 #else
82   *thread = (pthread_t)_beginthreadex(NULL,          /* void *security */
83                                       0,             /* unsigned stack_size */
84                                       start, arg, 0, /* unsigned initflag */
85                                       NULL);         /* unsigned *thrdaddr */
86 #endif
87   if (*thread == NULL) return 1;
88   SetThreadPriority(*thread, THREAD_PRIORITY_ABOVE_NORMAL);
89   return 0;
90 }
91 
pthread_join(pthread_t thread,void ** value_ptr)92 static INLINE int pthread_join(pthread_t thread, void **value_ptr) {
93   (void)value_ptr;
94   return (WaitForSingleObject(thread, INFINITE) != WAIT_OBJECT_0 ||
95           CloseHandle(thread) == 0);
96 }
97 
98 // Mutex
pthread_mutex_init(pthread_mutex_t * const mutex,void * mutexattr)99 static INLINE int pthread_mutex_init(pthread_mutex_t *const mutex,
100                                      void *mutexattr) {
101   (void)mutexattr;
102 #if _WIN32_WINNT >= 0x0600  // Windows Vista / Server 2008 or greater
103   InitializeCriticalSectionEx(mutex, 0 /*dwSpinCount*/, 0 /*Flags*/);
104 #else
105   InitializeCriticalSection(mutex);
106 #endif
107   return 0;
108 }
109 
pthread_mutex_trylock(pthread_mutex_t * const mutex)110 static INLINE int pthread_mutex_trylock(pthread_mutex_t *const mutex) {
111   return TryEnterCriticalSection(mutex) ? 0 : EBUSY;
112 }
113 
pthread_mutex_lock(pthread_mutex_t * const mutex)114 static INLINE int pthread_mutex_lock(pthread_mutex_t *const mutex) {
115   EnterCriticalSection(mutex);
116   return 0;
117 }
118 
pthread_mutex_unlock(pthread_mutex_t * const mutex)119 static INLINE int pthread_mutex_unlock(pthread_mutex_t *const mutex) {
120   LeaveCriticalSection(mutex);
121   return 0;
122 }
123 
pthread_mutex_destroy(pthread_mutex_t * const mutex)124 static INLINE int pthread_mutex_destroy(pthread_mutex_t *const mutex) {
125   DeleteCriticalSection(mutex);
126   return 0;
127 }
128 
129 // Condition
pthread_cond_destroy(pthread_cond_t * const condition)130 static INLINE int pthread_cond_destroy(pthread_cond_t *const condition) {
131   int ok = 1;
132 #ifdef USE_WINDOWS_CONDITION_VARIABLE
133   (void)condition;
134 #else
135   ok &= (CloseHandle(condition->waiting_sem_) != 0);
136   ok &= (CloseHandle(condition->received_sem_) != 0);
137   ok &= (CloseHandle(condition->signal_event_) != 0);
138 #endif
139   return !ok;
140 }
141 
pthread_cond_init(pthread_cond_t * const condition,void * cond_attr)142 static INLINE int pthread_cond_init(pthread_cond_t *const condition,
143                                     void *cond_attr) {
144   (void)cond_attr;
145 #ifdef USE_WINDOWS_CONDITION_VARIABLE
146   InitializeConditionVariable(condition);
147 #else
148   condition->waiting_sem_ = CreateSemaphore(NULL, 0, MAX_DECODE_THREADS, NULL);
149   condition->received_sem_ = CreateSemaphore(NULL, 0, MAX_DECODE_THREADS, NULL);
150   condition->signal_event_ = CreateEvent(NULL, FALSE, FALSE, NULL);
151   if (condition->waiting_sem_ == NULL || condition->received_sem_ == NULL ||
152       condition->signal_event_ == NULL) {
153     pthread_cond_destroy(condition);
154     return 1;
155   }
156 #endif
157   return 0;
158 }
159 
pthread_cond_signal(pthread_cond_t * const condition)160 static INLINE int pthread_cond_signal(pthread_cond_t *const condition) {
161   int ok = 1;
162 #ifdef USE_WINDOWS_CONDITION_VARIABLE
163   WakeConditionVariable(condition);
164 #else
165   if (WaitForSingleObject(condition->waiting_sem_, 0) == WAIT_OBJECT_0) {
166     // a thread is waiting in pthread_cond_wait: allow it to be notified
167     ok = SetEvent(condition->signal_event_);
168     // wait until the event is consumed so the signaler cannot consume
169     // the event via its own pthread_cond_wait.
170     ok &= (WaitForSingleObject(condition->received_sem_, INFINITE) !=
171            WAIT_OBJECT_0);
172   }
173 #endif
174   return !ok;
175 }
176 
pthread_cond_broadcast(pthread_cond_t * const condition)177 static INLINE int pthread_cond_broadcast(pthread_cond_t *const condition) {
178   int ok = 1;
179 #ifdef USE_WINDOWS_CONDITION_VARIABLE
180   WakeAllConditionVariable(condition);
181 #else
182   while (WaitForSingleObject(condition->waiting_sem_, 0) == WAIT_OBJECT_0) {
183     // a thread is waiting in pthread_cond_wait: allow it to be notified
184     ok &= SetEvent(condition->signal_event_);
185     // wait until the event is consumed so the signaler cannot consume
186     // the event via its own pthread_cond_wait.
187     ok &= (WaitForSingleObject(condition->received_sem_, INFINITE) !=
188            WAIT_OBJECT_0);
189   }
190 #endif
191   return !ok;
192 }
193 
pthread_cond_wait(pthread_cond_t * const condition,pthread_mutex_t * const mutex)194 static INLINE int pthread_cond_wait(pthread_cond_t *const condition,
195                                     pthread_mutex_t *const mutex) {
196   int ok;
197 #ifdef USE_WINDOWS_CONDITION_VARIABLE
198   ok = SleepConditionVariableCS(condition, mutex, INFINITE);
199 #else
200   // note that there is a consumer available so the signal isn't dropped in
201   // pthread_cond_signal
202   if (!ReleaseSemaphore(condition->waiting_sem_, 1, NULL)) return 1;
203   // now unlock the mutex so pthread_cond_signal may be issued
204   pthread_mutex_unlock(mutex);
205   ok = (WaitForSingleObject(condition->signal_event_, INFINITE) ==
206         WAIT_OBJECT_0);
207   ok &= ReleaseSemaphore(condition->received_sem_, 1, NULL);
208   pthread_mutex_lock(mutex);
209 #endif
210   return !ok;
211 }
212 #elif defined(__OS2__)
213 #define INCL_DOS
214 #include <os2.h>  // NOLINT
215 
216 #include <errno.h>        // NOLINT
217 #include <stdlib.h>       // NOLINT
218 #include <sys/builtin.h>  // NOLINT
219 
220 #define pthread_t TID
221 #define pthread_mutex_t HMTX
222 
223 typedef struct {
224   HEV event_sem_;
225   HEV ack_sem_;
226   volatile unsigned wait_count_;
227 } pthread_cond_t;
228 
229 //------------------------------------------------------------------------------
230 // simplistic pthread emulation layer
231 
232 #define THREADFN void *
233 #define THREAD_RETURN(val) (val)
234 
235 typedef struct {
236   void *(*start_)(void *);
237   void *arg_;
238 } thread_arg;
239 
240 static void thread_start(void *arg) {
241   thread_arg targ = *(thread_arg *)arg;
242   free(arg);
243 
244   targ.start_(targ.arg_);
245 }
246 
247 static INLINE int pthread_create(pthread_t *const thread, const void *attr,
248                                  void *(*start)(void *), void *arg) {
249   int tid;
250   thread_arg *targ = (thread_arg *)malloc(sizeof(*targ));
251   if (targ == NULL) return 1;
252 
253   (void)attr;
254 
255   targ->start_ = start;
256   targ->arg_ = arg;
257   tid = (pthread_t)_beginthread(thread_start, NULL, 1024 * 1024, targ);
258   if (tid == -1) {
259     free(targ);
260     return 1;
261   }
262 
263   *thread = tid;
264   return 0;
265 }
266 
267 static INLINE int pthread_join(pthread_t thread, void **value_ptr) {
268   (void)value_ptr;
269   return DosWaitThread(&thread, DCWW_WAIT) != 0;
270 }
271 
272 // Mutex
273 static INLINE int pthread_mutex_init(pthread_mutex_t *const mutex,
274                                      void *mutexattr) {
275   (void)mutexattr;
276   return DosCreateMutexSem(NULL, mutex, 0, FALSE) != 0;
277 }
278 
279 static INLINE int pthread_mutex_trylock(pthread_mutex_t *const mutex) {
280   return DosRequestMutexSem(*mutex, SEM_IMMEDIATE_RETURN) == 0 ? 0 : EBUSY;
281 }
282 
283 static INLINE int pthread_mutex_lock(pthread_mutex_t *const mutex) {
284   return DosRequestMutexSem(*mutex, SEM_INDEFINITE_WAIT) != 0;
285 }
286 
287 static INLINE int pthread_mutex_unlock(pthread_mutex_t *const mutex) {
288   return DosReleaseMutexSem(*mutex) != 0;
289 }
290 
291 static INLINE int pthread_mutex_destroy(pthread_mutex_t *const mutex) {
292   return DosCloseMutexSem(*mutex) != 0;
293 }
294 
295 // Condition
296 static INLINE int pthread_cond_destroy(pthread_cond_t *const condition) {
297   int ok = 1;
298   ok &= DosCloseEventSem(condition->event_sem_) == 0;
299   ok &= DosCloseEventSem(condition->ack_sem_) == 0;
300   return !ok;
301 }
302 
303 static INLINE int pthread_cond_init(pthread_cond_t *const condition,
304                                     void *cond_attr) {
305   int ok = 1;
306   (void)cond_attr;
307 
308   ok &=
309       DosCreateEventSem(NULL, &condition->event_sem_, DCE_POSTONE, FALSE) == 0;
310   ok &= DosCreateEventSem(NULL, &condition->ack_sem_, DCE_POSTONE, FALSE) == 0;
311   if (!ok) {
312     pthread_cond_destroy(condition);
313     return 1;
314   }
315   condition->wait_count_ = 0;
316   return 0;
317 }
318 
319 static INLINE int pthread_cond_signal(pthread_cond_t *const condition) {
320   int ok = 1;
321 
322   if (!__atomic_cmpxchg32(&condition->wait_count_, 0, 0)) {
323     ok &= DosPostEventSem(condition->event_sem_) == 0;
324     ok &= DosWaitEventSem(condition->ack_sem_, SEM_INDEFINITE_WAIT) == 0;
325   }
326 
327   return !ok;
328 }
329 
330 static INLINE int pthread_cond_broadcast(pthread_cond_t *const condition) {
331   int ok = 1;
332 
333   while (!__atomic_cmpxchg32(&condition->wait_count_, 0, 0))
334     ok &= pthread_cond_signal(condition) == 0;
335 
336   return !ok;
337 }
338 
339 static INLINE int pthread_cond_wait(pthread_cond_t *const condition,
340                                     pthread_mutex_t *const mutex) {
341   int ok = 1;
342 
343   __atomic_increment(&condition->wait_count_);
344 
345   ok &= pthread_mutex_unlock(mutex) == 0;
346 
347   ok &= DosWaitEventSem(condition->event_sem_, SEM_INDEFINITE_WAIT) == 0;
348 
349   __atomic_decrement(&condition->wait_count_);
350 
351   ok &= DosPostEventSem(condition->ack_sem_) == 0;
352 
353   pthread_mutex_lock(mutex);
354 
355   return !ok;
356 }
357 #else                 // _WIN32
358 #include <pthread.h>  // NOLINT
359 #define THREADFN void *
360 #define THREAD_RETURN(val) val
361 #endif
362 
363 #endif  // CONFIG_MULTITHREAD
364 
365 // State of the worker thread object
366 typedef enum {
367   NOT_OK = 0,  // object is unusable
368   OK,          // ready to work
369   WORK         // busy finishing the current task
370 } AVxWorkerStatus;
371 
372 // Function to be called by the worker thread. Takes two opaque pointers as
373 // arguments (data1 and data2). Should return true on success and return false
374 // in case of error.
375 typedef int (*AVxWorkerHook)(void *, void *);
376 
377 // Platform-dependent implementation details for the worker.
378 typedef struct AVxWorkerImpl AVxWorkerImpl;
379 
380 // Synchronization object used to launch job in the worker thread
381 typedef struct {
382   AVxWorkerImpl *impl_;
383   AVxWorkerStatus status_;
384   // Thread name for the debugger. If not NULL, must point to a string that
385   // outlives the worker thread. For portability, use a name <= 15 characters
386   // long (not including the terminating NUL character).
387   const char *thread_name;
388   AVxWorkerHook hook;  // hook to call
389   void *data1;         // first argument passed to 'hook'
390   void *data2;         // second argument passed to 'hook'
391   int had_error;       // true if a call to 'hook' returned false
392 } AVxWorker;
393 
394 // The interface for all thread-worker related functions. All these functions
395 // must be implemented.
396 typedef struct {
397   // Must be called first, before any other method.
398   void (*init)(AVxWorker *const worker);
399   // Must be called to initialize the object and spawn the thread. Re-entrant.
400   // Will potentially launch the thread. Returns false in case of error.
401   int (*reset)(AVxWorker *const worker);
402   // Makes sure the previous work is finished. Returns true if worker->had_error
403   // was not set and no error condition was triggered by the working thread.
404   int (*sync)(AVxWorker *const worker);
405   // Triggers the thread to call hook() with data1 and data2 arguments. These
406   // hook/data1/data2 values can be changed at any time before calling this
407   // function, but not be changed afterward until the next call to Sync().
408   void (*launch)(AVxWorker *const worker);
409   // This function is similar to launch() except that it calls the
410   // hook directly instead of using a thread. Convenient to bypass the thread
411   // mechanism while still using the AVxWorker structs. sync() must
412   // still be called afterward (for error reporting).
413   void (*execute)(AVxWorker *const worker);
414   // Kill the thread and terminate the object. To use the object again, one
415   // must call reset() again.
416   void (*end)(AVxWorker *const worker);
417 } AVxWorkerInterface;
418 
419 // Install a new set of threading functions, overriding the defaults. This
420 // should be done before any workers are started, i.e., before any encoding or
421 // decoding takes place. The contents of the interface struct are copied, it
422 // is safe to free the corresponding memory after this call. This function is
423 // not thread-safe. Return false in case of invalid pointer or methods.
424 int aom_set_worker_interface(const AVxWorkerInterface *const winterface);
425 
426 // Retrieve the currently set thread worker interface.
427 const AVxWorkerInterface *aom_get_worker_interface(void);
428 
429 //------------------------------------------------------------------------------
430 
431 #ifdef __cplusplus
432 }  // extern "C"
433 #endif
434 
435 #endif  // AOM_AOM_UTIL_AOM_THREAD_H_
436