[NaCl SDK] nacl_io: Add support for basic socketpairs.

native_client_sdk/src/libraries/nacl_io/socket/unix_event_emitter.h

+// Copyright 2015 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_SOCKET_UNIX_EVENT_EMITTER_H_
+#define LIBRARIES_NACL_IO_SOCKET_UNIX_EVENT_EMITTER_H_
+
+#include "nacl_io/fifo_char.h"
+#include "nacl_io/stream/stream_event_emitter.h"
+
+#include "sdk_util/macros.h"
+#include "sdk_util/scoped_ref.h"
+#include "sdk_util/simple_lock.h"
+
+namespace nacl_io {
+
+class UnixEventEmitter;
+class Node;
+
+typedef sdk_util::ScopedRef<UnixEventEmitter> ScopedUnixEventEmitter;
+
+class UnixEventEmitter : public StreamEventEmitter {
+ public:
+  uint32_t ReadIn_Locked(char* buffer, uint32_t len);
+  uint32_t WriteOut_Locked(const char* buffer, uint32_t len);
+
+  uint32_t BytesInOutputFIFO();
+  uint32_t SpaceInInputFIFO();
+
+  virtual ScopedUnixEventEmitter GetPeerEmitter() = 0;
+
+  static ScopedUnixEventEmitter MakeUnixEventEmitter(size_t size);
+
+ protected:
+  UnixEventEmitter() {}
+
+  // Probably only need the master's lock.
+  virtual const sdk_util::SimpleLock& GetFifoLock() = 0;
+  virtual FIFOInterface* in_fifo() { return in_fifoc(); }
+  virtual FIFOInterface* out_fifo() { return out_fifoc(); }
+  virtual FIFOChar* in_fifoc() = 0;
+  virtual FIFOChar* out_fifoc() = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(UnixEventEmitter);
+};
+
+}  // namespace nacl_io
+
+#endif  // LIBRARIES_NACL_IO_SOCKET_UNIX_EVENT_EMITTER_H_