[Chromoting] Add DataChannelManager to manage optional incoming data channels

remoting/protocol/named_message_pipe_handler.h

+// Copyright 2017 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 REMOTING_PROTOCOL_NAMED_MESSAGE_PIPE_HANDLER_H_
+#define REMOTING_PROTOCOL_NAMED_MESSAGE_PIPE_HANDLER_H_
+
+#include <memory>
+#include <string>
+
+#include "base/callback.h"
+#include "base/sequenced_task_runner_helpers.h"
+#include "base/threading/thread_checker.h"
+#include "remoting/protocol/message_pipe.h"
+
+namespace google {
+namespace protobuf {
+class MessageLite;
+}  // namespace protobuf
+}  // namespace google
+
+namespace remoting {
+
+class CompoundBuffer;
+
+namespace protocol {
+
+// A base class to handle data from a named MessagePipe. This class manages the
+// lifetime itself: it deletes itself once the MessagePipe is closed or the
+// derived instance actively calls Close() function.
+class NamedMessagePipeHandler : public MessagePipe::EventHandler {
+ protected:
+  // The callers should create instances of derived classes instead of this
+  // class. So hide the constructor.
+  NamedMessagePipeHandler(const std::string& name,
+                          std::unique_ptr<MessagePipe> pipe);
+
+  ~NamedMessagePipeHandler() override;
+
+  // Closes the channel and eventually destructs this instance. No operations
+  // should be performed after executing this function.
+  void Close();
+
+  const std::string& pipe_name() const { return name_; }
+
+  // Whether |pipe_| has been connected.
+  bool connected() const { return is_connected_; }
+
+  // Sends the message through the pipe. This function should only be called
+  // once connected() returns true.
+  void Send(google::protobuf::MessageLite* message, const base::Closure& done);
+
+  // Derived classes can override these functions to receive data from the
+  // connection or observe the connection state. These functions will not be
+  // called unless |pipe_| has been opened.
+  virtual void OnIncomingMessage(std::unique_ptr<CompoundBuffer> message);
+  virtual void OnConnected();
+  virtual void OnDisconnecting();
+
+ private:
+  friend class base::DeleteHelper<NamedMessagePipeHandler>;
+
+  // MessagePipe::EventHandler implementation.
+  void OnMessagePipeOpen() override;
+  void OnMessageReceived(std::unique_ptr<CompoundBuffer> message) override;
+  void OnMessagePipeClosed() override;
+
+  const std::string name_;
+  std::unique_ptr<MessagePipe> pipe_;
+  base::ThreadChecker thread_checker_;
+  bool is_connected_ = false;
+};
+
+}  // namespace protocol
+}  // namespace remoting
+
+#endif  // REMOTING_PROTOCOL_NAMED_MESSAGE_PIPE_HANDLER_H_