chromium/net/dns/system_dns_config_change_notifier.h

// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_DNS_SYSTEM_DNS_CONFIG_CHANGE_NOTIFIER_H_
#define NET_DNS_SYSTEM_DNS_CONFIG_CHANGE_NOTIFIER_H_

#include <memory>
#include <optional>

#include "base/memory/scoped_refptr.h"
#include "base/task/sequenced_task_runner.h"
#include "net/base/net_export.h"
#include "net/dns/dns_config.h"

namespace net {

class DnsConfigService;

// Notifier that can be subscribed to to listen for changes to system DNS
// configuration. Expected to only be used internally to HostResolverManager and
// NetworkChangeNotifier. Other classes are expected to subscribe to
// NetworkChangeNotifier::AddDNSObserver() to subscribe to listen to both system
// config changes and configuration applied on top by Chrome.
//
// This class is thread and sequence safe except that RemoveObserver() must be
// called on the same sequence as the matched AddObserver() call.
//
// TODO(crbug.com/40630884): Use this class in HostResolverManager.
class NET_EXPORT_PRIVATE SystemDnsConfigChangeNotifier { … };

}  // namespace net

#endif  // NET_DNS_SYSTEM_DNS_CONFIG_CHANGE_NOTIFIER_H_