rtc_base/mdns_responder_interface.h

/*
 *  Copyright 2018 The WebRTC Project Authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#ifndef RTC_BASE_MDNS_RESPONDER_INTERFACE_H_
#define RTC_BASE_MDNS_RESPONDER_INTERFACE_H_

#include <functional>
#include <string>

#include "rtc_base/ipaddress.h"

namespace webrtc {

// Defines an mDNS responder that can be used in ICE candidate gathering, where
// the local IP addresses of host candidates are replaced by mDNS hostnames.
class MdnsResponderInterface {
 public:
  using NameCreatedCallback =
      std::function<void(const rtc::IPAddress&, const std::string&)>;
  using NameRemovedCallback = std::function<void(bool)>;

  MdnsResponderInterface() = default;
  virtual ~MdnsResponderInterface() = default;

  // Asynchronously creates and returns a new name via |callback| for |addr| if
  // there is no name mapped to it by this responder, and initializes the
  // reference count of this name to one. Otherwise the existing name mapped to
  // |addr| is returned and its reference count is incremented by one.
  virtual void CreateNameForAddress(const rtc::IPAddress& addr,
                                    NameCreatedCallback callback) = 0;
  // Decrements the reference count of the mapped name of |addr|, if
  // there is a map created previously via CreateNameForAddress; asynchronously
  // removes the association between |addr| and its mapped name, and returns
  // true via |callback| if the decremented reference count reaches zero.
  // Otherwise no operation is done and false is returned via |callback|
  // asynchronously.
  virtual void RemoveNameForAddress(const rtc::IPAddress& addr,
                                    NameRemovedCallback callback) = 0;
};

}  // namespace webrtc

#endif  // RTC_BASE_MDNS_RESPONDER_INTERFACE_H_