diff options
Diffstat (limited to 'media/libwebp/src/utils/thread_utils.c')
| -rw-r--r-- | media/libwebp/src/utils/thread_utils.c | 369 |
1 files changed, 369 insertions, 0 deletions
diff --git a/media/libwebp/src/utils/thread_utils.c b/media/libwebp/src/utils/thread_utils.c new file mode 100644 index 0000000000..4e470e17ac --- /dev/null +++ b/media/libwebp/src/utils/thread_utils.c @@ -0,0 +1,369 @@ +// Copyright 2011 Google Inc. All Rights Reserved. +// +// Use of this source code is governed by a BSD-style license +// that can be found in the COPYING file in the root of the source +// tree. An additional intellectual property rights grant can be found +// in the file PATENTS. All contributing project authors may +// be found in the AUTHORS file in the root of the source tree. +// ----------------------------------------------------------------------------- +// +// Multi-threaded worker +// +// Author: Skal (pascal.massimino@gmail.com) + +#include <assert.h> +#include <string.h> // for memset() +#include "src/utils/thread_utils.h" +#include "src/utils/utils.h" + +#ifdef WEBP_USE_THREAD + +#if defined(_WIN32) + +#include <windows.h> +typedef HANDLE pthread_t; +typedef CRITICAL_SECTION pthread_mutex_t; + +#if _WIN32_WINNT >= 0x0600 // Windows Vista / Server 2008 or greater +#define USE_WINDOWS_CONDITION_VARIABLE +typedef CONDITION_VARIABLE pthread_cond_t; +#else +typedef struct { + HANDLE waiting_sem_; + HANDLE received_sem_; + HANDLE signal_event_; +} pthread_cond_t; +#endif // _WIN32_WINNT >= 0x600 + +#ifndef WINAPI_FAMILY_PARTITION +#define WINAPI_PARTITION_DESKTOP 1 +#define WINAPI_FAMILY_PARTITION(x) x +#endif + +#if !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP) +#define USE_CREATE_THREAD +#endif + +#else // !_WIN32 + +#include <pthread.h> + +#endif // _WIN32 + +typedef struct { + pthread_mutex_t mutex_; + pthread_cond_t condition_; + pthread_t thread_; +} WebPWorkerImpl; + +#if defined(_WIN32) + +//------------------------------------------------------------------------------ +// simplistic pthread emulation layer + +#include <process.h> + +// _beginthreadex requires __stdcall +#define THREADFN unsigned int __stdcall +#define THREAD_RETURN(val) (unsigned int)((DWORD_PTR)val) + +#if _WIN32_WINNT >= 0x0501 // Windows XP or greater +#define WaitForSingleObject(obj, timeout) \ + WaitForSingleObjectEx(obj, timeout, FALSE /*bAlertable*/) +#endif + +static int pthread_create(pthread_t* const thread, const void* attr, + unsigned int (__stdcall* start)(void*), void* arg) { + (void)attr; +#ifdef USE_CREATE_THREAD + *thread = CreateThread(NULL, /* lpThreadAttributes */ + 0, /* dwStackSize */ + start, + arg, + 0, /* dwStackSize */ + NULL); /* lpThreadId */ +#else + *thread = (pthread_t)_beginthreadex(NULL, /* void *security */ + 0, /* unsigned stack_size */ + start, + arg, + 0, /* unsigned initflag */ + NULL); /* unsigned *thrdaddr */ +#endif + if (*thread == NULL) return 1; + SetThreadPriority(*thread, THREAD_PRIORITY_ABOVE_NORMAL); + return 0; +} + +static int pthread_join(pthread_t thread, void** value_ptr) { + (void)value_ptr; + return (WaitForSingleObject(thread, INFINITE) != WAIT_OBJECT_0 || + CloseHandle(thread) == 0); +} + +// Mutex +static int pthread_mutex_init(pthread_mutex_t* const mutex, void* mutexattr) { + (void)mutexattr; +#if _WIN32_WINNT >= 0x0600 // Windows Vista / Server 2008 or greater + InitializeCriticalSectionEx(mutex, 0 /*dwSpinCount*/, 0 /*Flags*/); +#else + InitializeCriticalSection(mutex); +#endif + return 0; +} + +static int pthread_mutex_lock(pthread_mutex_t* const mutex) { + EnterCriticalSection(mutex); + return 0; +} + +static int pthread_mutex_unlock(pthread_mutex_t* const mutex) { + LeaveCriticalSection(mutex); + return 0; +} + +static int pthread_mutex_destroy(pthread_mutex_t* const mutex) { + DeleteCriticalSection(mutex); + return 0; +} + +// Condition +static int pthread_cond_destroy(pthread_cond_t* const condition) { + int ok = 1; +#ifdef USE_WINDOWS_CONDITION_VARIABLE + (void)condition; +#else + ok &= (CloseHandle(condition->waiting_sem_) != 0); + ok &= (CloseHandle(condition->received_sem_) != 0); + ok &= (CloseHandle(condition->signal_event_) != 0); +#endif + return !ok; +} + +static int pthread_cond_init(pthread_cond_t* const condition, void* cond_attr) { + (void)cond_attr; +#ifdef USE_WINDOWS_CONDITION_VARIABLE + InitializeConditionVariable(condition); +#else + condition->waiting_sem_ = CreateSemaphore(NULL, 0, 1, NULL); + condition->received_sem_ = CreateSemaphore(NULL, 0, 1, NULL); + condition->signal_event_ = CreateEvent(NULL, FALSE, FALSE, NULL); + if (condition->waiting_sem_ == NULL || + condition->received_sem_ == NULL || + condition->signal_event_ == NULL) { + pthread_cond_destroy(condition); + return 1; + } +#endif + return 0; +} + +static int pthread_cond_signal(pthread_cond_t* const condition) { + int ok = 1; +#ifdef USE_WINDOWS_CONDITION_VARIABLE + WakeConditionVariable(condition); +#else + if (WaitForSingleObject(condition->waiting_sem_, 0) == WAIT_OBJECT_0) { + // a thread is waiting in pthread_cond_wait: allow it to be notified + ok = SetEvent(condition->signal_event_); + // wait until the event is consumed so the signaler cannot consume + // the event via its own pthread_cond_wait. + ok &= (WaitForSingleObject(condition->received_sem_, INFINITE) != + WAIT_OBJECT_0); + } +#endif + return !ok; +} + +static int pthread_cond_wait(pthread_cond_t* const condition, + pthread_mutex_t* const mutex) { + int ok; +#ifdef USE_WINDOWS_CONDITION_VARIABLE + ok = SleepConditionVariableCS(condition, mutex, INFINITE); +#else + // note that there is a consumer available so the signal isn't dropped in + // pthread_cond_signal + if (!ReleaseSemaphore(condition->waiting_sem_, 1, NULL)) return 1; + // now unlock the mutex so pthread_cond_signal may be issued + pthread_mutex_unlock(mutex); + ok = (WaitForSingleObject(condition->signal_event_, INFINITE) == + WAIT_OBJECT_0); + ok &= ReleaseSemaphore(condition->received_sem_, 1, NULL); + pthread_mutex_lock(mutex); +#endif + return !ok; +} + +#else // !_WIN32 +# define THREADFN void* +# define THREAD_RETURN(val) val +#endif // _WIN32 + +//------------------------------------------------------------------------------ + +static THREADFN ThreadLoop(void* ptr) { + WebPWorker* const worker = (WebPWorker*)ptr; + WebPWorkerImpl* const impl = (WebPWorkerImpl*)worker->impl_; + int done = 0; + while (!done) { + pthread_mutex_lock(&impl->mutex_); + while (worker->status_ == OK) { // wait in idling mode + pthread_cond_wait(&impl->condition_, &impl->mutex_); + } + if (worker->status_ == WORK) { + WebPGetWorkerInterface()->Execute(worker); + worker->status_ = OK; + } else if (worker->status_ == NOT_OK) { // finish the worker + done = 1; + } + // signal to the main thread that we're done (for Sync()) + // Note the associated mutex does not need to be held when signaling the + // condition. Unlocking the mutex first may improve performance in some + // implementations, avoiding the case where the waiting thread can't + // reacquire the mutex when woken. + pthread_mutex_unlock(&impl->mutex_); + pthread_cond_signal(&impl->condition_); + } + return THREAD_RETURN(NULL); // Thread is finished +} + +// main thread state control +static void ChangeState(WebPWorker* const worker, WebPWorkerStatus new_status) { + // No-op when attempting to change state on a thread that didn't come up. + // Checking status_ without acquiring the lock first would result in a data + // race. + WebPWorkerImpl* const impl = (WebPWorkerImpl*)worker->impl_; + if (impl == NULL) return; + + pthread_mutex_lock(&impl->mutex_); + if (worker->status_ >= OK) { + // wait for the worker to finish + while (worker->status_ != OK) { + pthread_cond_wait(&impl->condition_, &impl->mutex_); + } + // assign new status and release the working thread if needed + if (new_status != OK) { + worker->status_ = new_status; + // Note the associated mutex does not need to be held when signaling the + // condition. Unlocking the mutex first may improve performance in some + // implementations, avoiding the case where the waiting thread can't + // reacquire the mutex when woken. + pthread_mutex_unlock(&impl->mutex_); + pthread_cond_signal(&impl->condition_); + return; + } + } + pthread_mutex_unlock(&impl->mutex_); +} + +#endif // WEBP_USE_THREAD + +//------------------------------------------------------------------------------ + +static void Init(WebPWorker* const worker) { + memset(worker, 0, sizeof(*worker)); + worker->status_ = NOT_OK; +} + +static int Sync(WebPWorker* const worker) { +#ifdef WEBP_USE_THREAD + ChangeState(worker, OK); +#endif + assert(worker->status_ <= OK); + return !worker->had_error; +} + +static int Reset(WebPWorker* const worker) { + int ok = 1; + worker->had_error = 0; + if (worker->status_ < OK) { +#ifdef WEBP_USE_THREAD + WebPWorkerImpl* const impl = + (WebPWorkerImpl*)WebPSafeCalloc(1, sizeof(WebPWorkerImpl)); + worker->impl_ = (void*)impl; + if (worker->impl_ == NULL) { + return 0; + } + if (pthread_mutex_init(&impl->mutex_, NULL)) { + goto Error; + } + if (pthread_cond_init(&impl->condition_, NULL)) { + pthread_mutex_destroy(&impl->mutex_); + goto Error; + } + pthread_mutex_lock(&impl->mutex_); + ok = !pthread_create(&impl->thread_, NULL, ThreadLoop, worker); + if (ok) worker->status_ = OK; + pthread_mutex_unlock(&impl->mutex_); + if (!ok) { + pthread_mutex_destroy(&impl->mutex_); + pthread_cond_destroy(&impl->condition_); + Error: + WebPSafeFree(impl); + worker->impl_ = NULL; + return 0; + } +#else + worker->status_ = OK; +#endif + } else if (worker->status_ > OK) { + ok = Sync(worker); + } + assert(!ok || (worker->status_ == OK)); + return ok; +} + +static void Execute(WebPWorker* const worker) { + if (worker->hook != NULL) { + worker->had_error |= !worker->hook(worker->data1, worker->data2); + } +} + +static void Launch(WebPWorker* const worker) { +#ifdef WEBP_USE_THREAD + ChangeState(worker, WORK); +#else + Execute(worker); +#endif +} + +static void End(WebPWorker* const worker) { +#ifdef WEBP_USE_THREAD + if (worker->impl_ != NULL) { + WebPWorkerImpl* const impl = (WebPWorkerImpl*)worker->impl_; + ChangeState(worker, NOT_OK); + pthread_join(impl->thread_, NULL); + pthread_mutex_destroy(&impl->mutex_); + pthread_cond_destroy(&impl->condition_); + WebPSafeFree(impl); + worker->impl_ = NULL; + } +#else + worker->status_ = NOT_OK; + assert(worker->impl_ == NULL); +#endif + assert(worker->status_ == NOT_OK); +} + +//------------------------------------------------------------------------------ + +static WebPWorkerInterface g_worker_interface = { + Init, Reset, Sync, Launch, Execute, End +}; + +int WebPSetWorkerInterface(const WebPWorkerInterface* const winterface) { + if (winterface == NULL || + winterface->Init == NULL || winterface->Reset == NULL || + winterface->Sync == NULL || winterface->Launch == NULL || + winterface->Execute == NULL || winterface->End == NULL) { + return 0; + } + g_worker_interface = *winterface; + return 1; +} + +const WebPWorkerInterface* WebPGetWorkerInterface(void) { + return &g_worker_interface; +} + +//------------------------------------------------------------------------------ |