[NaCl SDK] Upate atomic ops in nacl_io

native_client_sdk/src/libraries/sdk_util/simple_lock.h

+/* Copyright (c) 2013 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef LIBRARIES_SDK_UTIL_SIMPLE_LOCK_H_
+#define LIBRARIES_SDK_UTIL_SIMPLE_LOCK_H_
+
+#include "pthread.h"
+#include "sdk_util/macros.h"
+
+/*
+ * SimpleLock
+ *
+ * A pthread mutex object, with automatic initialization and destruction.
+ * Should be used with AutoLock where possible.
+ */
+class SimpleLock {
+ public:
+  SimpleLock() {
+    pthread_mutex_init(&lock_, NULL);
+  }
+
+  ~SimpleLock() {
+    pthread_mutex_destroy(&lock_);
+  }
+
+  pthread_mutex_t* mutex() const { return &lock_; }
+
+ private:
+  mutable pthread_mutex_t lock_;
+
+  DISALLOW_COPY_AND_ASSIGN(SimpleLock);
+};
+
+#endif  // LIBRARIES_SDK_UTIL_SIMPLE_LOCK_H_
+