libvpx: Pull from upstream

source/libvpx/vp9/decoder/vp9_thread.c

Index: source/libvpx/vp9/decoder/vp9_thread.c
===================================================================
--- source/libvpx/vp9/decoder/vp9_thread.c	(revision 251189)
+++ source/libvpx/vp9/decoder/vp9_thread.c	(working copy)
@@ -24,118 +24,8 @@
 
 #if CONFIG_MULTITHREAD
 
-#if defined(_WIN32)
-
 //------------------------------------------------------------------------------
-// simplistic pthread emulation layer
 
-#include <process.h>  // NOLINT
-
-// _beginthreadex requires __stdcall
-#define THREADFN unsigned int __stdcall
-#define THREAD_RETURN(val) (unsigned int)((DWORD_PTR)val)
-
-static int pthread_create(pthread_t* const thread, const void* attr,
-                          unsigned int (__stdcall *start)(void*), void* arg) {
-  (void)attr;
-  *thread = (pthread_t)_beginthreadex(NULL,   /* void *security */
-                                      0,      /* unsigned stack_size */
-                                      start,
-                                      arg,
-                                      0,      /* unsigned initflag */
-                                      NULL);  /* unsigned *thrdaddr */
-  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;
-  InitializeCriticalSection(mutex);
-  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;
-  ok &= (CloseHandle(condition->waiting_sem_) != 0);
-  ok &= (CloseHandle(condition->received_sem_) != 0);
-  ok &= (CloseHandle(condition->signal_event_) != 0);
-  return !ok;
-}
-
-static int pthread_cond_init(pthread_cond_t* const condition, void* cond_attr) {
-  (void)cond_attr;
-  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;
-  }
-  return 0;
-}
-
-static int pthread_cond_signal(pthread_cond_t* const condition) {
-  int ok = 1;
-  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);
-  }
-  return !ok;
-}
-
-static int pthread_cond_wait(pthread_cond_t* const condition,
-                             pthread_mutex_t* const mutex) {
-  int ok;
-  // 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);
-  return !ok;
-}
-
-#else  // _WIN32
-# define THREADFN void*
-# define THREAD_RETURN(val) val
-#endif
-
-//------------------------------------------------------------------------------
-
 static THREADFN thread_loop(void *ptr) {    // thread loop
   VP9Worker* const worker = (VP9Worker*)ptr;
   int done = 0;