chromium/remoting/host/heartbeat_sender.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 REMOTING_HOST_HEARTBEAT_SENDER_H_
#define REMOTING_HOST_HEARTBEAT_SENDER_H_

#include <memory>
#include <optional>
#include <string>
#include <optional>

#include "base/functional/callback.h"
#include "base/gtest_prod_util.h"
#include "base/memory/raw_ptr.h"
#include "base/sequence_checker.h"
#include "base/timer/timer.h"
#include "net/base/backoff_entry.h"
#include "remoting/proto/remoting/v1/directory_messages.pb.h"
#include "remoting/signaling/signal_strategy.h"

namespace base {
class TimeDelta;
}  // namespace base

namespace network {
class SharedURLLoaderFactory;
}  // namespace network

namespace remoting {

class OAuthTokenGetter;
class ProtobufHttpStatus;

// HeartbeatSender periodically sends heartbeat to the directory service. See
// the HeartbeatRequest message in directory_messages.proto for more details.
//
// Normally the heartbeat indicates that the host is healthy and ready to
// accept new connections from a client, but the message can optionally include
// a host_offline_reason field, which indicates that the host cannot accept
// connections from the client (and might possibly be shutting down).  The value
// of the host_offline_reason field can be either a string from
// host_exit_codes.cc (i.e. "INVALID_HOST_CONFIGURATION" string) or one of
// kHostOfflineReasonXxx constants (i.e. "POLICY_READ_ERROR" string).
//
// The heartbeat sender will verify that the channel is in fact active before
// sending out the heartbeat. If not, it will disconnect the signaling strategy
// so that the signaling connector will try to reconnect signaling.
//
// The server sends a HeartbeatResponse in response to each successful
// heartbeat.
class HeartbeatSender final : public SignalStrategy::Listener { … };

}  // namespace remoting

#endif  // REMOTING_HOST_HEARTBEAT_SENDER_H_