Remote assistance on Chrome OS Part IV - It2MeHost

remoting/host/it2me/it2me_host.cc

 // Copyright 2013 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.
 
 #include "remoting/host/it2me/it2me_host.h"
 
 #include "base/bind.h"
 #include "base/strings/string_util.h"
-#include "base/synchronization/waitable_event.h"
 #include "base/threading/platform_thread.h"
 #include "net/socket/client_socket_factory.h"
 #include "remoting/base/auto_thread.h"
 #include "remoting/base/logging.h"
 #include "remoting/base/rsa_key_pair.h"
 #include "remoting/host/chromoting_host.h"
 #include "remoting/host/chromoting_host_context.h"
 #include "remoting/host/host_event_logger.h"
 #include "remoting/host/host_secret.h"
 #include "remoting/host/host_status_logger.h"
@@ skipping 16 matching lines @@
 }  // namespace
 
 It2MeHost::It2MeHost(
     ChromotingHostContext* host_context,
     scoped_refptr<base::SingleThreadTaskRunner> task_runner,
     base::WeakPtr<It2MeHost::Observer> observer,
     const XmppSignalStrategy::XmppServerConfig& xmpp_server_config,
     const std::string& directory_bot_jid)
   : host_context_(host_context),
     task_runner_(task_runner),
+    network_task_runner_(host_context_->network_task_runner()),
     observer_(observer),
     xmpp_server_config_(xmpp_server_config),
     directory_bot_jid_(directory_bot_jid),
     state_(kDisconnected),
     failed_login_attempts_(0),
     nat_traversal_enabled_(false),
     policy_received_(false) {
   DCHECK(task_runner_->BelongsToCurrentThread());
 }
 
 void It2MeHost::Connect() {
   if (!host_context_->ui_task_runner()->BelongsToCurrentThread()) {
     DCHECK(task_runner_->BelongsToCurrentThread());
     host_context_->ui_task_runner()->PostTask(
         FROM_HERE, base::Bind(&It2MeHost::Connect, this));
     return;
   }
 
   desktop_environment_factory_.reset(new It2MeDesktopEnvironmentFactory(
-      host_context_->network_task_runner(),
+      network_task_runner_,
       host_context_->input_task_runner(),
       host_context_->ui_task_runner()));
 
   // Start monitoring configured policies.
   policy_watcher_.reset(
-      policy_hack::PolicyWatcher::Create(host_context_->network_task_runner()));
+      policy_hack::PolicyWatcher::Create(host_context_, network_task_runner_));
   policy_watcher_->StartWatching(
       base::Bind(&It2MeHost::OnPolicyUpdate, this));
 
   // Switch to the network thread to start the actual connection.
-  host_context_->network_task_runner()->PostTask(
+  network_task_runner_->PostTask(
       FROM_HERE, base::Bind(&It2MeHost::ReadPolicyAndConnect, this));
 }
 
 void It2MeHost::Disconnect() {
-  if (!host_context_->network_task_runner()->BelongsToCurrentThread()) {
+  if (!network_task_runner_->BelongsToCurrentThread()) {
     DCHECK(task_runner_->BelongsToCurrentThread());
-    host_context_->network_task_runner()->PostTask(
+    network_task_runner_->PostTask(
         FROM_HERE, base::Bind(&It2MeHost::Disconnect, this));
     return;
   }
 
   switch (state_) {
     case kDisconnected:
       ShutdownOnNetworkThread();
       return;
 
     case kStarting:
@@ skipping 10 matching lines @@
 
       if (!host_) {
         SetState(kDisconnected);
         ShutdownOnNetworkThread();
         return;
       }
 
       // Deleting the host destroys SignalStrategy synchronously, but
       // SignalStrategy::Listener handlers are not allowed to destroy
       // SignalStrategy, so post task to destroy the host later.
-      host_context_->network_task_runner()->PostTask(
+      network_task_runner_->PostTask(
           FROM_HERE, base::Bind(&It2MeHost::ShutdownOnNetworkThread, this));
       return;
   }
 }
 
 void It2MeHost::RequestNatPolicy() {
-  if (!host_context_->network_task_runner()->BelongsToCurrentThread()) {
+  if (!network_task_runner_->BelongsToCurrentThread()) {
     DCHECK(task_runner_->BelongsToCurrentThread());
-    host_context_->network_task_runner()->PostTask(
+    network_task_runner_->PostTask(
         FROM_HERE, base::Bind(&It2MeHost::RequestNatPolicy, this));
     return;
   }
 
   if (policy_received_)
     UpdateNatPolicy(nat_traversal_enabled_);
 }
 
 void It2MeHost::ReadPolicyAndConnect() {
-  DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
+  DCHECK(network_task_runner_->BelongsToCurrentThread());
 
   SetState(kStarting);
 
   // Only proceed to FinishConnect() if at least one policy update has been
   // received.
   if (policy_received_) {
     FinishConnect();
   } else {
     // Otherwise, create the policy watcher, and thunk the connect.
     pending_connect_ =
         base::Bind(&It2MeHost::FinishConnect, this);
   }
 }
 
 void It2MeHost::FinishConnect() {
-  DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
+  DCHECK(network_task_runner_->BelongsToCurrentThread());
 
   if (state_ != kStarting) {
     // Host has been stopped while we were fetching policy.
     return;
   }
 
   // Check the host domain policy.
   if (!required_host_domain_.empty() &&
       !EndsWith(xmpp_server_config_.username,
                 std::string("@") + required_host_domain_, false)) {
@@ skipping 36 matching lines @@
   // Create the host.
   host_.reset(new ChromotingHost(
       signal_strategy_.get(),
       desktop_environment_factory_.get(),
       CreateHostSessionManager(signal_strategy_.get(), network_settings,
                                host_context_->url_request_context_getter()),
       host_context_->audio_task_runner(),
       host_context_->input_task_runner(),
       host_context_->video_capture_task_runner(),
       host_context_->video_encode_task_runner(),
-      host_context_->network_task_runner(),
+      network_task_runner_,
       host_context_->ui_task_runner()));
   host_->AddStatusObserver(this);
   host_status_logger_.reset(
       new HostStatusLogger(host_->AsWeakPtr(), ServerLogEntry::IT2ME,
                            signal_strategy_.get(), directory_bot_jid_));
 
   // Disable audio by default.
   // TODO(sergeyu): Add UI to enable it.
   scoped_ptr<protocol::CandidateSessionConfig> protocol_config =
       protocol::CandidateSessionConfig::CreateDefault();
   protocol_config->DisableAudioChannel();
 
   host_->set_protocol_config(protocol_config.Pass());
 
   // Create event logger.
   host_event_logger_ =
       HostEventLogger::Create(host_->AsWeakPtr(), kApplicationName);
 
   // Connect signaling and start the host.
   signal_strategy_->Connect();
   host_->Start(xmpp_server_config_.username);
 
   SetState(kRequestedAccessCode);
   return;
 }
 
 void It2MeHost::ShutdownOnNetworkThread() {
-  DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
+  DCHECK(network_task_runner_->BelongsToCurrentThread());
   DCHECK(state_ == kDisconnecting || state_ == kDisconnected);
 
   if (state_ == kDisconnecting) {
     host_event_logger_.reset();
     host_->RemoveStatusObserver(this);
     host_.reset();
 
     register_request_.reset();
     host_status_logger_.reset();
     signal_strategy_.reset();
     SetState(kDisconnected);
   }
 
-  host_context_->ui_task_runner()->PostTask(
-      FROM_HERE, base::Bind(&It2MeHost::ShutdownOnUiThread, this));
+  task_runner_->PostTask(FROM_HERE,

[Jamie, 2014/10/14 01:18:42]

Why has this changed?

[kelvinp, 2014/10/15 23:03:10]

As per wez, comment, we are trying to take reference on the task_runner of the
ChromotingHostContext instead of holding on to the host.

+                         base::Bind(&It2MeHost::ShutdownOnUiThread, this));
 }
 
 void It2MeHost::ShutdownOnUiThread() {
-  DCHECK(host_context_->ui_task_runner()->BelongsToCurrentThread());
+  DCHECK(task_runner_->BelongsToCurrentThread());
 
   // Destroy the DesktopEnvironmentFactory, to free thread references.
   desktop_environment_factory_.reset();
 
   // Stop listening for policy updates.
   if (policy_watcher_.get()) {
-    base::WaitableEvent policy_watcher_stopped_(true, false);
-    policy_watcher_->StopWatching(&policy_watcher_stopped_);
-    policy_watcher_stopped_.Wait();
-    policy_watcher_.reset();
+    policy_watcher_->StopWatching(
+        base::Bind(&It2MeHost::OnPolicyWatcherShutdown, this));
+    return;
   }
 }
 
+void It2MeHost::OnPolicyWatcherShutdown() {
+  policy_watcher_.reset();
+}
+
 void It2MeHost::OnAccessDenied(const std::string& jid) {
-  DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
+  DCHECK(network_task_runner_->BelongsToCurrentThread());
 
   ++failed_login_attempts_;
   if (failed_login_attempts_ == kMaxLoginAttempts) {
     Disconnect();
   }
 }
 
 void It2MeHost::OnClientAuthenticated(const std::string& jid) {
-  DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
+  DCHECK(network_task_runner_->BelongsToCurrentThread());
 
   if (state_ == kDisconnecting) {
     // Ignore the new connection if we are disconnecting.
     return;
   }
   if (state_ == kConnected) {
     // If we already connected another client then one of the connections may be
     // an attacker, so both are suspect and we have to reject the second
     // connection and shutdown the host.
     host_->RejectAuthenticatingClient();
@@ skipping 10 matching lines @@
 
   // Pass the client user name to the script object before changing state.
   task_runner_->PostTask(
       FROM_HERE, base::Bind(&It2MeHost::Observer::OnClientAuthenticated,
                             observer_, client_username));
 
   SetState(kConnected);
 }
 
 void It2MeHost::OnClientDisconnected(const std::string& jid) {
-  DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
+  DCHECK(network_task_runner_->BelongsToCurrentThread());
 
   Disconnect();
 }
 
 void It2MeHost::OnPolicyUpdate(scoped_ptr<base::DictionaryValue> policies) {
-  DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
+  DCHECK(network_task_runner_->BelongsToCurrentThread());
 
   bool nat_policy;
   if (policies->GetBoolean(policy_hack::PolicyWatcher::kNatPolicyName,
                            &nat_policy)) {
     UpdateNatPolicy(nat_policy);
   }
   std::string host_domain;
   if (policies->GetString(policy_hack::PolicyWatcher::kHostDomainPolicyName,
                           &host_domain)) {
     UpdateHostDomainPolicy(host_domain);
   }
 
   policy_received_ = true;
 
   if (!pending_connect_.is_null()) {
     pending_connect_.Run();
     pending_connect_.Reset();
   }
 }
 
 void It2MeHost::UpdateNatPolicy(bool nat_traversal_enabled) {
-  DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
+  DCHECK(network_task_runner_->BelongsToCurrentThread());
 
   VLOG(2) << "UpdateNatPolicy: " << nat_traversal_enabled;
 
   // When transitioning from enabled to disabled, force disconnect any
   // existing session.
   if (nat_traversal_enabled_ && !nat_traversal_enabled && IsConnected()) {
     Disconnect();
   }
 
   nat_traversal_enabled_ = nat_traversal_enabled;
 
   // Notify the web-app of the policy setting.
   task_runner_->PostTask(
       FROM_HERE, base::Bind(&It2MeHost::Observer::OnNatPolicyChanged,
                             observer_, nat_traversal_enabled_));
 }
 
 void It2MeHost::UpdateHostDomainPolicy(const std::string& host_domain) {
-  DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
+  DCHECK(network_task_runner_->BelongsToCurrentThread());
 
   VLOG(2) << "UpdateHostDomainPolicy: " << host_domain;
 
   // When setting a host domain policy, force disconnect any existing session.
   if (!host_domain.empty() && IsConnected()) {
     Disconnect();
   }
 
   required_host_domain_ = host_domain;
 }
 
 It2MeHost::~It2MeHost() {
   // Check that resources that need to be torn down on the UI thread are gone.
   DCHECK(!desktop_environment_factory_.get());
   DCHECK(!policy_watcher_.get());
 }
 
 void It2MeHost::SetState(It2MeHostState state) {
-  DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
+  DCHECK(network_task_runner_->BelongsToCurrentThread());
 
   switch (state_) {
     case kDisconnected:
       DCHECK(state == kStarting ||
              state == kError) << state;
       break;
     case kStarting:
       DCHECK(state == kRequestedAccessCode ||
              state == kDisconnecting ||
              state == kError ||
@@ skipping 35 matching lines @@
 
 bool It2MeHost::IsConnected() const {
   return state_ == kRequestedAccessCode || state_ == kReceivedAccessCode ||
       state_ == kConnected;
 }
 
 void It2MeHost::OnReceivedSupportID(
     bool success,
     const std::string& support_id,
     const base::TimeDelta& lifetime) {
-  DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
+  DCHECK(network_task_runner_->BelongsToCurrentThread());
 
   if (!success) {
     SetState(kError);
     Disconnect();
     return;
   }
 
   std::string host_secret = GenerateSupportHostSecret();
   std::string access_code = support_id + host_secret;
 
@@ skipping 26 matching lines @@
     ChromotingHostContext* context,
     scoped_refptr<base::SingleThreadTaskRunner> task_runner,
     base::WeakPtr<It2MeHost::Observer> observer,
     const XmppSignalStrategy::XmppServerConfig& xmpp_server_config,
     const std::string& directory_bot_jid) {
   return new It2MeHost(
       context, task_runner, observer, xmpp_server_config, directory_bot_jid);
 }
 
 }  // namespace remoting