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-rw-r--r--media/libwebp/src/utils/thread_utils.c369
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diff --git a/media/libwebp/src/utils/thread_utils.c b/media/libwebp/src/utils/thread_utils.c
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+// 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;
+}
+
+//------------------------------------------------------------------------------