1 // Copyright 2013 Google Inc. All Rights Reserved. 2 // 3 // Use of this source code is governed by a BSD-style license 4 // that can be found in the COPYING file in the root of the source 5 // tree. An additional intellectual property rights grant can be found 6 // in the file PATENTS. All contributing project authors may 7 // be found in the AUTHORS file in the root of the source tree. 8 // ----------------------------------------------------------------------------- 9 // 10 // Multi-threaded worker 11 // 12 // Original source: 13 // http://git.chromium.org/webm/libwebp.git 14 // 100644 blob 13a61a4c84194c3374080cbf03d881d3cd6af40d src/utils/thread.h 15 16 17 #ifndef VP9_DECODER_VP9_THREAD_H_ 18 #define VP9_DECODER_VP9_THREAD_H_ 19 20 #include "./vpx_config.h" 21 22 #ifdef __cplusplus 23 extern "C" { 24 #endif 25 26 #if CONFIG_MULTITHREAD 27 28 #if defined(_WIN32) 29 #include <errno.h> // NOLINT 30 #include <process.h> // NOLINT 31 #include <windows.h> // NOLINT 32 typedef HANDLE pthread_t; 33 typedef CRITICAL_SECTION pthread_mutex_t; 34 typedef struct { 35 HANDLE waiting_sem_; 36 HANDLE received_sem_; 37 HANDLE signal_event_; 38 } pthread_cond_t; 39 40 //------------------------------------------------------------------------------ 41 // simplistic pthread emulation layer 42 43 // _beginthreadex requires __stdcall 44 #define THREADFN unsigned int __stdcall 45 #define THREAD_RETURN(val) (unsigned int)((DWORD_PTR)val) 46 47 static INLINE int pthread_create(pthread_t* const thread, const void* attr, 48 unsigned int (__stdcall *start)(void*), 49 void* arg) { 50 (void)attr; 51 *thread = (pthread_t)_beginthreadex(NULL, /* void *security */ 52 0, /* unsigned stack_size */ 53 start, 54 arg, 55 0, /* unsigned initflag */ 56 NULL); /* unsigned *thrdaddr */ 57 if (*thread == NULL) return 1; 58 SetThreadPriority(*thread, THREAD_PRIORITY_ABOVE_NORMAL); 59 return 0; 60 } 61 62 static INLINE int pthread_join(pthread_t thread, void** value_ptr) { 63 (void)value_ptr; 64 return (WaitForSingleObject(thread, INFINITE) != WAIT_OBJECT_0 || 65 CloseHandle(thread) == 0); 66 } 67 68 // Mutex 69 static INLINE int pthread_mutex_init(pthread_mutex_t *const mutex, 70 void* mutexattr) { 71 (void)mutexattr; 72 InitializeCriticalSection(mutex); 73 return 0; 74 } 75 76 static INLINE int pthread_mutex_trylock(pthread_mutex_t *const mutex) { 77 return TryEnterCriticalSection(mutex) ? 0 : EBUSY; 78 } 79 80 static INLINE int pthread_mutex_lock(pthread_mutex_t *const mutex) { 81 EnterCriticalSection(mutex); 82 return 0; 83 } 84 85 static INLINE int pthread_mutex_unlock(pthread_mutex_t *const mutex) { 86 LeaveCriticalSection(mutex); 87 return 0; 88 } 89 90 static INLINE int pthread_mutex_destroy(pthread_mutex_t *const mutex) { 91 DeleteCriticalSection(mutex); 92 return 0; 93 } 94 95 // Condition 96 static INLINE int pthread_cond_destroy(pthread_cond_t *const condition) { 97 int ok = 1; 98 ok &= (CloseHandle(condition->waiting_sem_) != 0); 99 ok &= (CloseHandle(condition->received_sem_) != 0); 100 ok &= (CloseHandle(condition->signal_event_) != 0); 101 return !ok; 102 } 103 104 static INLINE int pthread_cond_init(pthread_cond_t *const condition, 105 void* cond_attr) { 106 (void)cond_attr; 107 condition->waiting_sem_ = CreateSemaphore(NULL, 0, 1, NULL); 108 condition->received_sem_ = CreateSemaphore(NULL, 0, 1, NULL); 109 condition->signal_event_ = CreateEvent(NULL, FALSE, FALSE, NULL); 110 if (condition->waiting_sem_ == NULL || 111 condition->received_sem_ == NULL || 112 condition->signal_event_ == NULL) { 113 pthread_cond_destroy(condition); 114 return 1; 115 } 116 return 0; 117 } 118 119 static INLINE int pthread_cond_signal(pthread_cond_t *const condition) { 120 int ok = 1; 121 if (WaitForSingleObject(condition->waiting_sem_, 0) == WAIT_OBJECT_0) { 122 // a thread is waiting in pthread_cond_wait: allow it to be notified 123 ok = SetEvent(condition->signal_event_); 124 // wait until the event is consumed so the signaler cannot consume 125 // the event via its own pthread_cond_wait. 126 ok &= (WaitForSingleObject(condition->received_sem_, INFINITE) != 127 WAIT_OBJECT_0); 128 } 129 return !ok; 130 } 131 132 static INLINE int pthread_cond_wait(pthread_cond_t *const condition, 133 pthread_mutex_t *const mutex) { 134 int ok; 135 // note that there is a consumer available so the signal isn't dropped in 136 // pthread_cond_signal 137 if (!ReleaseSemaphore(condition->waiting_sem_, 1, NULL)) 138 return 1; 139 // now unlock the mutex so pthread_cond_signal may be issued 140 pthread_mutex_unlock(mutex); 141 ok = (WaitForSingleObject(condition->signal_event_, INFINITE) == 142 WAIT_OBJECT_0); 143 ok &= ReleaseSemaphore(condition->received_sem_, 1, NULL); 144 pthread_mutex_lock(mutex); 145 return !ok; 146 } 147 #else // _WIN32 148 #include <pthread.h> // NOLINT 149 # define THREADFN void* 150 # define THREAD_RETURN(val) val 151 #endif 152 153 #endif // CONFIG_MULTITHREAD 154 155 // State of the worker thread object 156 typedef enum { 157 NOT_OK = 0, // object is unusable 158 OK, // ready to work 159 WORK // busy finishing the current task 160 } VP9WorkerStatus; 161 162 // Function to be called by the worker thread. Takes two opaque pointers as 163 // arguments (data1 and data2), and should return false in case of error. 164 typedef int (*VP9WorkerHook)(void*, void*); 165 166 // Synchronize object used to launch job in the worker thread 167 typedef struct { 168 #if CONFIG_MULTITHREAD 169 pthread_mutex_t mutex_; 170 pthread_cond_t condition_; 171 pthread_t thread_; 172 #endif 173 VP9WorkerStatus status_; 174 VP9WorkerHook hook; // hook to call 175 void* data1; // first argument passed to 'hook' 176 void* data2; // second argument passed to 'hook' 177 int had_error; // return value of the last call to 'hook' 178 } VP9Worker; 179 180 // Must be called first, before any other method. 181 void vp9_worker_init(VP9Worker* const worker); 182 // Must be called to initialize the object and spawn the thread. Re-entrant. 183 // Will potentially launch the thread. Returns false in case of error. 184 int vp9_worker_reset(VP9Worker* const worker); 185 // Makes sure the previous work is finished. Returns true if worker->had_error 186 // was not set and no error condition was triggered by the working thread. 187 int vp9_worker_sync(VP9Worker* const worker); 188 // Triggers the thread to call hook() with data1 and data2 argument. These 189 // hook/data1/data2 can be changed at any time before calling this function, 190 // but not be changed afterward until the next call to vp9_worker_sync(). 191 void vp9_worker_launch(VP9Worker* const worker); 192 // This function is similar to vp9_worker_launch() except that it calls the 193 // hook directly instead of using a thread. Convenient to bypass the thread 194 // mechanism while still using the VP9Worker structs. vp9_worker_sync() must 195 // still be called afterward (for error reporting). 196 void vp9_worker_execute(VP9Worker* const worker); 197 // Kill the thread and terminate the object. To use the object again, one 198 // must call vp9_worker_reset() again. 199 void vp9_worker_end(VP9Worker* const worker); 200 201 //------------------------------------------------------------------------------ 202 203 #ifdef __cplusplus 204 } // extern "C" 205 #endif 206 207 #endif // VP9_DECODER_VP9_THREAD_H_ 208
