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

remoting/host/host_signaling_manager.h

Index: remoting/host/host_signaling_manager.h
diff --git a/remoting/host/host_signaling_manager.h b/remoting/host/host_signaling_manager.h
new file mode 100644
index 0000000000000000000000000000000000000000..32587f907149f48ed4c82b08d9d9e91693ab31a4
--- /dev/null
+++ b/remoting/host/host_signaling_manager.h
@@ -0,0 +1,109 @@
+// 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_SIGNALING_MANAGER_H_
+#define REMOTING_HOST_HOST_SIGNALING_MANAGER_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/memory/scoped_ptr.h"
+#include "remoting/base/auto_thread_task_runner.h"
+#include "remoting/base/rsa_key_pair.h"
+#include "remoting/host/oauth_token_getter.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;
+
+// HostSignalingManager has 2 functions:
+// 1. Keep sending regular heartbeats to the Chromoting Directory.
+// 2. Keep the host process alive while sending host-offline-reason heartbeat.
+class HostSignalingManager {
+ public:
+  // TODO(lukasza): Refactor to limit the number of parameters below.
+  // Probably necessitates refactoring HostProcess to extract a new
+  // class to read and store config/policy/cmdline values.
+  //
+  // |on_heartbeat_successful_callback| is invoked after the first successful
+  // heartbeat.
+  //
+  // |on_heartbeat_successful_callback| is invoked when the host ID is
+  // permanently not recognized by the server.
+  //
+  // |on_auth_failed_callback| is invoked when authentication fails.
+  //
+  // |directory_bot_jid| is typically equal to "remoting@bot.talk.google.com".
+  static scoped_ptr<HostSignalingManager> 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 scoped_refptr<AutoThreadTaskRunner>& network_task_runner,
+      const scoped_refptr<net::URLRequestContextGetter>&
+          url_request_context_getter,
+      const XmppSignalStrategy::XmppServerConfig& xmpp_server_config,
+      const std::string& talkgadget_prefix_policy,
+      const std::string& host_id,
+      const scoped_refptr<const RsaKeyPair>& host_key_pair,
+      const std::string& directory_bot_jid,
+      scoped_ptr<OAuthTokenGetter::OAuthCredentials> oauth_credentials);
+
+  ~HostSignalingManager();
+
+  // Get the SignalStrategy to use for talking to the Chromoting bot.
+  // Returned SignalStrategy remains owned by the HostSignalingManager.
+  SignalStrategy* signal_strategy() { return signal_strategy_.get(); }
+
+  // Kicks off sending a heartbeat containing a host-offline-reason attribute.
+  //
+  // Will delete |this| once either the bot acks receiving the
+  // |host_offline_reason|, or the |timeout| is reached.  Deleting
+  // |this| will release |network_task_runner_| and allow the host
+  // process to exit.

[Wez, 2015/01/08 01:49:51]

Note here that the caller *must* release this object, so that it won't get
double-deleted.

[Łukasz Anforowicz, 2015/01/08 23:50:31]

Done.

+  void SendHostOfflineReasonAndDelete(const std::string& host_offline_reason,
+                                      const base::TimeDelta& timeout);
+
+ private:
+  HostSignalingManager(
+      const scoped_refptr<AutoThreadTaskRunner>& network_task_runner,

[Wez, 2015/01/08 01:49:51]

What prompted the const&?

[Łukasz Anforowicz, 2015/01/08 23:50:31]

In general, scoped_refptr should be passed by const-ref to avoid unnecessary
calls to AddRef/Release and ref-count churn.  OTOH, I am not sure where exactly
I found this advise (but pretty sure that it was recently and originating from
within Chromium docs or code or forums).

I did this when replacing chromoting_context in HostSignalingManager::Create
with network_task_runner + url_request_context_getter (and noticing that Create
passes its scoped_refptr references to places that also could declare the
scoped_refptr parameter as a const-ref).

+      scoped_ptr<net::NetworkChangeNotifier> network_change_notifier,
+      scoped_ptr<SignalStrategy> signal_strategy,
+      scoped_ptr<SignalingConnector> signaling_connector,
+      scoped_ptr<HeartbeatSender> heartbeat_sender);
+
+  void OnHostOfflineReasonAck(bool success);
+
+  // Order of fields below is important for destroying them in the right order.
+  // - |heartbeat_sender_| and |signaling_connector_| have to be destroyed
+  //   before |signal_strategy_| because their destructors need to call
+  //   signal_strategy_->RemoveListener(this)
+  // - |signaling_connector_| has to be destroyed before
+  //   |network_change_notifier_| because its destructor needs to deregister
+  //   network change notifications
+  scoped_refptr<AutoThreadTaskRunner> network_task_runner_;
+  scoped_ptr<net::NetworkChangeNotifier> network_change_notifier_;
+  scoped_ptr<SignalStrategy> signal_strategy_;
+  scoped_ptr<SignalingConnector> signaling_connector_;
+  scoped_ptr<HeartbeatSender> heartbeat_sender_;
+
+  DISALLOW_COPY_AND_ASSIGN(HostSignalingManager);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_HOST_SIGNALING_MANAGER_H_