Reporting of policy errors via host-offline-reason: part 3

remoting/host/minimum_heartbeat_supporter.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_MINIMUM_HEARTBEAT_SUPPORTER_H_
+#define REMOTING_HOST_MINIMUM_HEARTBEAT_SUPPORTER_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/time/time.h"
+#include "remoting/base/auto_thread_task_runner.h"
+#include "remoting/base/rsa_key_pair.h"
+#include "remoting/host/ack_or_timeout_reporter.h"
+#include "remoting/signaling/xmpp_signal_strategy.h"
+
+namespace base {
+  class TimeDelta;
+}
+
+namespace net {
+  class NetworkChangeNotifier;
+}
+
+namespace remoting {
+
+class ChromotingHostContext;
+class DnsBlackholeChecker;
+class HeartbeatSender;
+class OAuthTokenGetter;
+class SignalStrategy;
+class SignalingConnector;
+
+// Keeping an instance of MinimumHeartbeatSupporter alive
+// ensures that we keep trying to send heartbeats (which among other
+// things means that it ensures that we don't exit the host process).
+//
+// Primary scenario where this class is useful is extending host process
+// lifetime after |SendHostOfflineReason| is called.
+//
+// Secondary benefit of this class is hiding/encapsulating heartbeat
+// and xmpp related things inside.
+class MinimumHeartbeatSupporter
+    : public base::RefCounted<MinimumHeartbeatSupporter> {

[Lambros, 2014/11/19 02:29:42]

Do we need ref-counting here? Will this have multiple owners, or can
single-ownership be transferred between owners?

[Łukasz Anforowicz, 2014/11/19 21:44:24]

There are 2 owners:
1) HostProcess
2) AckOrTimeout callback created in
MinimumHeartbeatSender::SendHostOfflineReason

+ public:
+  static scoped_refptr<MinimumHeartbeatSupporter> Create(
+      const base::Closure& on_heartbeat_successful_callback,
+      const base::Closure& on_unknown_host_id_error_callback,
+      const base::Closure& on_auth_failed_callback,
+      const ChromotingHostContext& host_context,
+      const XmppSignalStrategy::XmppServerConfig& xmpp_server_config,
+      const std::string& talkgadget_prefix,
+      const std::string& host_id,
+      const scoped_refptr<RsaKeyPair> key_pair,
+      const std::string& directory_bot_jid,
+      const std::string& oauth_refresh_token,
+      bool use_service_account);
+
+  // Gets signal strategy used for talking to the Chromoting bot.
+  // Return value is valid until |this| gets deleted.
+  SignalStrategy* GetSignalStrategy();
+
+  // Kicks off sending a heartbeat containing a host-offline-reason attribute.
+  //
+  // Ensures that |this| (and transitively the whole process) is kept alive
+  // while waiting for an ack from the bot (this is subject to |timeout|).
+  void SendHostOfflineReason(
+      const std::string& host_offline_reason,
+      const base::TimeDelta& timeout);
+
+ private:
+  // Ref-counting helpers.
+  friend class base::RefCounted<MinimumHeartbeatSupporter>;
+  ~MinimumHeartbeatSupporter();
+
+  MinimumHeartbeatSupporter(
+      scoped_refptr<AutoThreadTaskRunner> network_task_runner,
+      scoped_ptr<net::NetworkChangeNotifier> network_change_notifier,
+      scoped_ptr<XmppSignalStrategy> signal_strategy,
+      scoped_ptr<SignalingConnector> signaling_connector,
+      scoped_ptr<HeartbeatSender> heartbeat_sender);
+
+  void OnAckOrTimeout(AckOrTimeout ack_or_timeout);
+
+  scoped_refptr<AutoThreadTaskRunner> network_task_runner_;
+  scoped_ptr<net::NetworkChangeNotifier> network_change_notifier_;
+  scoped_ptr<XmppSignalStrategy> signal_strategy_;
+  scoped_ptr<SignalingConnector> signaling_connector_;
+  scoped_ptr<HeartbeatSender> heartbeat_sender_;
+
+  DISALLOW_COPY_AND_ASSIGN(MinimumHeartbeatSupporter);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_MINIMUM_HEARTBEAT_SUPPORTER_H_