libvpx: Pull from upstream

source/libvpx/vp9/decoder/vp9_thread.c

 // Copyright 2013 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
 //
 // Original source:
 //  http://git.chromium.org/webm/libwebp.git
-//  100644 blob eff8f2a8c20095aade3c292b0e9292dac6cb3587  src/utils/thread.c
-
+//  100644 blob 08ad4e1fecba302bf1247645e84a7d2779956bc3  src/utils/thread.c
 
 #include <assert.h>
 #include <string.h>   // for memset()
 #include "./vp9_thread.h"
-
-#if defined(__cplusplus) || defined(c_plusplus)
-extern "C" {
-#endif
+#include "vpx_mem/vpx_mem.h"
 
 #if CONFIG_MULTITHREAD
 
+struct VP9WorkerImpl {
+  pthread_mutex_t mutex_;
+  pthread_cond_t  condition_;
+  pthread_t       thread_;
+};
+
 //------------------------------------------------------------------------------
 
-static THREADFN thread_loop(void *ptr) {    // thread loop
-  VP9Worker* const worker = (VP9Worker*)ptr;
+static void execute(VP9Worker *const worker);  // Forward declaration.
+
+static THREADFN thread_loop(void *ptr) {
+  VP9Worker *const worker = (VP9Worker*)ptr;
   int done = 0;
   while (!done) {
-    pthread_mutex_lock(&worker->mutex_);
+    pthread_mutex_lock(&worker->impl_->mutex_);
     while (worker->status_ == OK) {   // wait in idling mode
-      pthread_cond_wait(&worker->condition_, &worker->mutex_);
+      pthread_cond_wait(&worker->impl_->condition_, &worker->impl_->mutex_);
     }
     if (worker->status_ == WORK) {
-      vp9_worker_execute(worker);
+      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())
-    pthread_cond_signal(&worker->condition_);
-    pthread_mutex_unlock(&worker->mutex_);
+    // signal to the main thread that we're done (for sync())
+    pthread_cond_signal(&worker->impl_->condition_);
+    pthread_mutex_unlock(&worker->impl_->mutex_);
   }
   return THREAD_RETURN(NULL);    // Thread is finished
 }
 
 // main thread state control
-static void change_state(VP9Worker* const worker,
+static void change_state(VP9Worker *const worker,
                          VP9WorkerStatus new_status) {
-  // no-op when attempting to change state on a thread that didn't come up
-  if (worker->status_ < OK) return;
+  // 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.
+  if (worker->impl_ == NULL) return;
 
-  pthread_mutex_lock(&worker->mutex_);
-  // wait for the worker to finish
-  while (worker->status_ != OK) {
-    pthread_cond_wait(&worker->condition_, &worker->mutex_);
+  pthread_mutex_lock(&worker->impl_->mutex_);
+  if (worker->status_ >= OK) {
+    // wait for the worker to finish
+    while (worker->status_ != OK) {
+      pthread_cond_wait(&worker->impl_->condition_, &worker->impl_->mutex_);
+    }
+    // assign new status and release the working thread if needed
+    if (new_status != OK) {
+      worker->status_ = new_status;
+      pthread_cond_signal(&worker->impl_->condition_);
+    }
   }
-  // assign new status and release the working thread if needed
-  if (new_status != OK) {
-    worker->status_ = new_status;
-    pthread_cond_signal(&worker->condition_);
-  }
-  pthread_mutex_unlock(&worker->mutex_);
+  pthread_mutex_unlock(&worker->impl_->mutex_);
 }
 
 #endif  // CONFIG_MULTITHREAD
 
 //------------------------------------------------------------------------------
 
-void vp9_worker_init(VP9Worker* const worker) {
+static void init(VP9Worker *const worker) {
   memset(worker, 0, sizeof(*worker));
   worker->status_ = NOT_OK;
 }
 
-int vp9_worker_sync(VP9Worker* const worker) {
+static int sync(VP9Worker *const worker) {
 #if CONFIG_MULTITHREAD
   change_state(worker, OK);
 #endif
   assert(worker->status_ <= OK);
   return !worker->had_error;
 }
 
-int vp9_worker_reset(VP9Worker* const worker) {
+static int reset(VP9Worker *const worker) {
   int ok = 1;
   worker->had_error = 0;
   if (worker->status_ < OK) {
 #if CONFIG_MULTITHREAD
-    if (pthread_mutex_init(&worker->mutex_, NULL) ||
-        pthread_cond_init(&worker->condition_, NULL)) {
+    worker->impl_ = (VP9WorkerImpl*)vpx_calloc(1, sizeof(*worker->impl_));
+    if (worker->impl_ == NULL) {
       return 0;
     }
-    pthread_mutex_lock(&worker->mutex_);
-    ok = !pthread_create(&worker->thread_, NULL, thread_loop, worker);
+    if (pthread_mutex_init(&worker->impl_->mutex_, NULL)) {
+      goto Error;
+    }
+    if (pthread_cond_init(&worker->impl_->condition_, NULL)) {
+      pthread_mutex_destroy(&worker->impl_->mutex_);
+      goto Error;
+    }
+    pthread_mutex_lock(&worker->impl_->mutex_);
+    ok = !pthread_create(&worker->impl_->thread_, NULL, thread_loop, worker);
     if (ok) worker->status_ = OK;
-    pthread_mutex_unlock(&worker->mutex_);
+    pthread_mutex_unlock(&worker->impl_->mutex_);
+    if (!ok) {
+      pthread_mutex_destroy(&worker->impl_->mutex_);
+      pthread_cond_destroy(&worker->impl_->condition_);
+ Error:
+      vpx_free(worker->impl_);
+      worker->impl_ = NULL;
+      return 0;
+    }
 #else
     worker->status_ = OK;
 #endif
   } else if (worker->status_ > OK) {
-    ok = vp9_worker_sync(worker);
+    ok = sync(worker);
   }
   assert(!ok || (worker->status_ == OK));
   return ok;
 }
 
-void vp9_worker_execute(VP9Worker* const worker) {
+static void execute(VP9Worker *const worker) {
   if (worker->hook != NULL) {
     worker->had_error |= !worker->hook(worker->data1, worker->data2);
   }
 }
 
-void vp9_worker_launch(VP9Worker* const worker) {
+static void launch(VP9Worker *const worker) {
 #if CONFIG_MULTITHREAD
   change_state(worker, WORK);
 #else
-  vp9_worker_execute(worker);
+  execute(worker);
 #endif
 }
 
-void vp9_worker_end(VP9Worker* const worker) {
+static void end(VP9Worker *const worker) {
   if (worker->status_ >= OK) {
 #if CONFIG_MULTITHREAD
     change_state(worker, NOT_OK);
-    pthread_join(worker->thread_, NULL);
-    pthread_mutex_destroy(&worker->mutex_);
-    pthread_cond_destroy(&worker->condition_);
+    pthread_join(worker->impl_->thread_, NULL);
+    pthread_mutex_destroy(&worker->impl_->mutex_);
+    pthread_cond_destroy(&worker->impl_->condition_);
 #else
     worker->status_ = NOT_OK;
 #endif
   }
+  vpx_free(worker->impl_);
+  worker->impl_ = NULL;
   assert(worker->status_ == NOT_OK);
 }
 
 //------------------------------------------------------------------------------
 
-#if defined(__cplusplus) || defined(c_plusplus)
-}    // extern "C"
-#endif
+static VP9WorkerInterface g_worker_interface = {
+  init, reset, sync, launch, execute, end
+};
+
+int vp9_set_worker_interface(const VP9WorkerInterface* 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 VP9WorkerInterface *vp9_get_worker_interface(void) {
+  return &g_worker_interface;
+}
+
+//------------------------------------------------------------------------------