remoting/signaling/message_reception_channel.h

// Copyright 2019 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_SIGNALING_MESSAGE_RECEPTION_CHANNEL_H_
#define REMOTING_SIGNALING_MESSAGE_RECEPTION_CHANNEL_H_

#include <list>
#include <memory>

#include "base/callback_forward.h"
#include "base/macros.h"
#include "remoting/signaling/ftl.pb.h"
#include "third_party/grpc/src/include/grpcpp/support/status.h"

namespace remoting {

class ScopedGrpcServerStream;

// Interface for starting or closing the server stream to receive messages from
// FTL backend.
class MessageReceptionChannel {
 public:
  using StreamOpener = base::RepeatingCallback<void(
      base::OnceCallback<void(std::unique_ptr<ScopedGrpcServerStream>)>
          on_stream_started,
      const base::RepeatingCallback<void(const ftl::ReceiveMessagesResponse&)>&
          on_incoming_msg,
      base::OnceCallback<void(const grpc::Status&)> on_channel_closed)>;
  using MessageCallback =
      base::RepeatingCallback<void(const ftl::InboxMessage&)>;
  using DoneCallback = base::OnceCallback<void(const grpc::Status& status)>;

  MessageReceptionChannel() = default;
  virtual ~MessageReceptionChannel() = default;

  virtual void Initialize(const StreamOpener& stream_opener,
                          const MessageCallback& on_incoming_msg) = 0;

  // Opens a server streaming channel to the FTL API to enable message reception
  // over the fast path. |on_done| is called to signal success or failure for
  // starting the stream.
  virtual void StartReceivingMessages(DoneCallback on_done) = 0;

  // Closes the streaming channel.
  virtual void StopReceivingMessages() = 0;

 private:
  DISALLOW_COPY_AND_ASSIGN(MessageReceptionChannel);
};

}  // namespace remoting

#endif  // REMOTING_SIGNALING_MESSAGE_RECEPTION_CHANNEL_H_