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
pthread_create(pthread_t * const thread,const void * attr,unsigned int (__stdcall * start)(void *),void * arg)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
pthread_join(pthread_t thread,void ** value_ptr)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
pthread_mutex_init(pthread_mutex_t * const mutex,void * mutexattr)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
pthread_mutex_trylock(pthread_mutex_t * const mutex)75 static INLINE int pthread_mutex_trylock(pthread_mutex_t *const mutex) {
76 return TryEnterCriticalSection(mutex) ? 0 : EBUSY;
77 }
78
pthread_mutex_lock(pthread_mutex_t * const mutex)79 static INLINE int pthread_mutex_lock(pthread_mutex_t *const mutex) {
80 EnterCriticalSection(mutex);
81 return 0;
82 }
83
pthread_mutex_unlock(pthread_mutex_t * const mutex)84 static INLINE int pthread_mutex_unlock(pthread_mutex_t *const mutex) {
85 LeaveCriticalSection(mutex);
86 return 0;
87 }
88
pthread_mutex_destroy(pthread_mutex_t * const mutex)89 static INLINE int pthread_mutex_destroy(pthread_mutex_t *const mutex) {
90 DeleteCriticalSection(mutex);
91 return 0;
92 }
93
94 // Condition
pthread_cond_destroy(pthread_cond_t * const 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
pthread_cond_init(pthread_cond_t * const condition,void * cond_attr)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
pthread_cond_signal(pthread_cond_t * const condition)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
pthread_cond_wait(pthread_cond_t * const condition,pthread_mutex_t * const mutex)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