[NaCl SDK] Support non blocking TCP/UDP

native_client_sdk/src/libraries/nacl_io/fifo_null.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_NACL_IO_FIFO_NULL_H_
+#define LIBRARIES_NACL_IO_FIFO_NULL_H_
+
+#include <stdint.h>
+#include <stdlib.h>
+
+namespace nacl_io {
+
+// FIFONull
+//
+// A null fifo is always ready to read or write, but never actually
+// provides or stores data.
+class FIFONull : public FIFOInterface {
+ public:
+  virtual bool IsEmpty() { return false; }
+  virtual bool IsFull() { return false; }
+  virtual bool Resize(size_t) { return false; }
+
+  virtual uint32_t ReadAvailable() { return 1; }
+  virtual uint32_t WriteAvailable() { return 1; }
+};
+
+}  // namespace nacl_io
+
+#endif  // LIBRARIES_NACL_IO_FIFO_NULL_H_