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 7bd451b124ae3b81596abfbcc823e3cb129d3a38 src/utils/thread.h 15 16 #ifndef VP9_DECODER_VP9_THREAD_H_ 17 #define VP9_DECODER_VP9_THREAD_H_ 18 19 #include "./vpx_config.h" 20 21 #ifdef __cplusplus 22 extern "C" { 23 #endif 24 25 #if CONFIG_MULTITHREAD 26 27 #if defined(_WIN32) 28 #include <errno.h> // NOLINT 29 #include <process.h> // NOLINT 30 #include <windows.h> // NOLINT 31 typedef HANDLE pthread_t; 32 typedef CRITICAL_SECTION pthread_mutex_t; 33 typedef struct { 34 HANDLE waiting_sem_; 35 HANDLE received_sem_; 36 HANDLE signal_event_; 37 } pthread_cond_t; 38 39 //------------------------------------------------------------------------------ 40 // simplistic pthread emulation layer 41 42 // _beginthreadex requires __stdcall 43 #define THREADFN unsigned int __stdcall 44 #define THREAD_RETURN(val) (unsigned int)((DWORD_PTR)val) 45 46 static INLINE int pthread_create(pthread_t* const thread, const void* attr, 47 unsigned int (__stdcall *start)(void*), 48 void* arg) { 49 (void)attr; 50 *thread = (pthread_t)_beginthreadex(NULL, /* void *security */ 51 0, /* unsigned stack_size */ 52 start, 53 arg, 54 0, /* unsigned initflag */ 55 NULL); /* unsigned *thrdaddr */ 56 if (*thread == NULL) return 1; 57 SetThreadPriority(*thread, THREAD_PRIORITY_ABOVE_NORMAL); 58 return 0; 59 } 60 61 static INLINE int pthread_join(pthread_t thread, void** value_ptr) { 62 (void)value_ptr; 63 return (WaitForSingleObject(thread, INFINITE) != WAIT_OBJECT_0 || 64 CloseHandle(thread) == 0); 65 } 66 67 // Mutex 68 static INLINE int pthread_mutex_init(pthread_mutex_t *const mutex, 69 void* mutexattr) { 70 (void)mutexattr; 71 InitializeCriticalSection(mutex); 72 return 0; 73 } 74 75 static INLINE int pthread_mutex_trylock(pthread_mutex_t *const mutex) { 76 return TryEnterCriticalSection(mutex) ? 0 : EBUSY; 77 } 78 79 static INLINE int pthread_mutex_lock(pthread_mutex_t *const mutex) { 80 EnterCriticalSection(mutex); 81 return 0; 82 } 83 84 static INLINE int pthread_mutex_unlock(pthread_mutex_t *const mutex) { 85 LeaveCriticalSection(mutex); 86 return 0; 87 } 88 89 static INLINE int pthread_mutex_destroy(pthread_mutex_t *const mutex) { 90 DeleteCriticalSection(mutex); 91 return 0; 92 } 93 94 // Condition 95 static INLINE int pthread_cond_destroy(pthread_cond_t *const condition) { 96 int ok = 1; 97 ok &= (CloseHandle(condition->waiting_sem_) != 0); 98 ok &= (CloseHandle(condition->received_sem_) != 0); 99 ok &= (CloseHandle(condition->signal_event_) != 0); 100 return !ok; 101 } 102 103 static INLINE int pthread_cond_init(pthread_cond_t *const condition, 104 void* cond_attr) { 105 (void)cond_attr; 106 condition->waiting_sem_ = CreateSemaphore(NULL, 0, 1, NULL); 107 condition->received_sem_ = CreateSemaphore(NULL, 0, 1, NULL); 108 condition->signal_event_ = CreateEvent(NULL, FALSE, FALSE, NULL); 109 if (condition->waiting_sem_ == NULL || 110 condition->received_sem_ == NULL || 111 condition->signal_event_ == NULL) { 112 pthread_cond_destroy(condition); 113 return 1; 114 } 115 return 0; 116 } 117 118 static INLINE int pthread_cond_signal(pthread_cond_t *const condition) { 119 int ok = 1; 120 if (WaitForSingleObject(condition->waiting_sem_, 0) == WAIT_OBJECT_0) { 121 // a thread is waiting in pthread_cond_wait: allow it to be notified 122 ok = SetEvent(condition->signal_event_); 123 // wait until the event is consumed so the signaler cannot consume 124 // the event via its own pthread_cond_wait. 125 ok &= (WaitForSingleObject(condition->received_sem_, INFINITE) != 126 WAIT_OBJECT_0); 127 } 128 return !ok; 129 } 130 131 static INLINE int pthread_cond_wait(pthread_cond_t *const condition, 132 pthread_mutex_t *const mutex) { 133 int ok; 134 // note that there is a consumer available so the signal isn't dropped in 135 // pthread_cond_signal 136 if (!ReleaseSemaphore(condition->waiting_sem_, 1, NULL)) 137 return 1; 138 // now unlock the mutex so pthread_cond_signal may be issued 139 pthread_mutex_unlock(mutex); 140 ok = (WaitForSingleObject(condition->signal_event_, INFINITE) == 141 WAIT_OBJECT_0); 142 ok &= ReleaseSemaphore(condition->received_sem_, 1, NULL); 143 pthread_mutex_lock(mutex); 144 return !ok; 145 } 146 #else // _WIN32 147 #include <pthread.h> // NOLINT 148 # define THREADFN void* 149 # define THREAD_RETURN(val) val 150 #endif 151 152 #endif // CONFIG_MULTITHREAD 153 154 // State of the worker thread object 155 typedef enum { 156 NOT_OK = 0, // object is unusable 157 OK, // ready to work 158 WORK // busy finishing the current task 159 } VP9WorkerStatus; 160 161 // Function to be called by the worker thread. Takes two opaque pointers as 162 // arguments (data1 and data2), and should return false in case of error. 163 typedef int (*VP9WorkerHook)(void*, void*); 164 165 // Platform-dependent implementation details for the worker. 166 typedef struct VP9WorkerImpl VP9WorkerImpl; 167 168 // Synchronization object used to launch job in the worker thread 169 typedef struct { 170 VP9WorkerImpl *impl_; 171 VP9WorkerStatus status_; 172 VP9WorkerHook hook; // hook to call 173 void *data1; // first argument passed to 'hook' 174 void *data2; // second argument passed to 'hook' 175 int had_error; // return value of the last call to 'hook' 176 } VP9Worker; 177 178 // The interface for all thread-worker related functions. All these functions 179 // must be implemented. 180 typedef struct { 181 // Must be called first, before any other method. 182 void (*init)(VP9Worker *const worker); 183 // Must be called to initialize the object and spawn the thread. Re-entrant. 184 // Will potentially launch the thread. Returns false in case of error. 185 int (*reset)(VP9Worker *const worker); 186 // Makes sure the previous work is finished. Returns true if worker->had_error 187 // was not set and no error condition was triggered by the working thread. 188 int (*sync)(VP9Worker *const worker); 189 // Triggers the thread to call hook() with data1 and data2 arguments. These 190 // hook/data1/data2 values can be changed at any time before calling this 191 // function, but not be changed afterward until the next call to Sync(). 192 void (*launch)(VP9Worker *const worker); 193 // This function is similar to launch() except that it calls the 194 // hook directly instead of using a thread. Convenient to bypass the thread 195 // mechanism while still using the VP9Worker structs. sync() must 196 // still be called afterward (for error reporting). 197 void (*execute)(VP9Worker *const worker); 198 // Kill the thread and terminate the object. To use the object again, one 199 // must call reset() again. 200 void (*end)(VP9Worker *const worker); 201 } VP9WorkerInterface; 202 203 // Install a new set of threading functions, overriding the defaults. This 204 // should be done before any workers are started, i.e., before any encoding or 205 // decoding takes place. The contents of the interface struct are copied, it 206 // is safe to free the corresponding memory after this call. This function is 207 // not thread-safe. Return false in case of invalid pointer or methods. 208 int vp9_set_worker_interface(const VP9WorkerInterface *const winterface); 209 210 // Retrieve the currently set thread worker interface. 211 const VP9WorkerInterface *vp9_get_worker_interface(void); 212 213 //------------------------------------------------------------------------------ 214 215 #ifdef __cplusplus 216 } // extern "C" 217 #endif 218 219 #endif // VP9_DECODER_VP9_THREAD_H_ 220
