remoting/host/host_extension_session.h

// Copyright 2014 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_HOST_HOST_EXTENSION_SESSION_H_
#define REMOTING_HOST_HOST_EXTENSION_SESSION_H_

#include "base/memory/scoped_ptr.h"

namespace webrtc {
class DesktopCapturer;
}

namespace remoting {

class ClientSessionControl;
class VideoEncoder;

namespace protocol {
class ExtensionMessage;
class ClientStub;
}  // namespace protocol

// Created by an |HostExtension| to store |ClientSession| specific state, and to
// handle extension messages.
class HostExtensionSession {
 public:
  virtual ~HostExtensionSession() {}

  // Hook functions called when the video pipeline is being (re)constructed.
  // Implementations will receive these calls only if they express the need to
  // modify the pipeline (see below). They may replace or wrap |capturer| and/or
  // |encoder|, e.g. to filter video frames in some way.
  // If either |capturer| or |encoder| are reset then the video pipeline is not
  // constructed.
  virtual void OnCreateVideoCapturer(
      scoped_ptr<webrtc::DesktopCapturer>* capturer);
  virtual void OnCreateVideoEncoder(scoped_ptr<VideoEncoder>* encoder);

  // Must return true if the HostExtensionSession needs the opportunity to
  // modify the video pipeline.
  virtual bool ModifiesVideoPipeline() const;

  // Called when the host receives an |ExtensionMessage| for the |ClientSession|
  // associated with this |HostExtensionSession|.
  // It returns |true| if the message was handled, and |false| otherwise.
  virtual bool OnExtensionMessage(
      ClientSessionControl* client_session_control,
      protocol::ClientStub* client_stub,
      const protocol::ExtensionMessage& message) = 0;
};

}  // namespace remoting

#endif  // REMOTING_HOST_HOST_EXTENSION_SESSION_H_