text: // Copyright 2017 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 "chromeos/components/tether/tether_network_disconnection_handler.h"
  
  #include "base/bind.h"
  #include "base/callback_helpers.h"
  #include "base/memory/ptr_util.h"
  #include "base/metrics/histogram_macros.h"
  #include "base/threading/thread_task_runner_handle.h"
  #include "chromeos/components/multidevice/logging/logging.h"
  #include "chromeos/components/tether/disconnect_tethering_request_sender.h"
  #include "chromeos/components/tether/network_configuration_remover.h"
  #include "chromeos/components/tether/tether_disconnector.h"
  #include "chromeos/components/tether/tether_host_fetcher.h"
  #include "chromeos/components/tether/tether_session_completion_logger.h"
  #include "chromeos/network/network_handler.h"
  #include "chromeos/network/network_state.h"
  #include "chromeos/network/network_state_handler.h"
  
  namespace chromeos {
  
  namespace tether {
  
  TetherNetworkDisconnectionHandler::TetherNetworkDisconnectionHandler(
      ActiveHost* active_host,
      NetworkStateHandler* network_state_handler,
      NetworkConfigurationRemover* network_configuration_remover,
      DisconnectTetheringRequestSender* disconnect_tethering_request_sender,
      TetherSessionCompletionLogger* tether_session_completion_logger)
      : active_host_(active_host),
        network_state_handler_(network_state_handler),
        network_configuration_remover_(network_configuration_remover),
        disconnect_tethering_request_sender_(disconnect_tethering_request_sender),
        tether_session_completion_logger_(tether_session_completion_logger),
        task_runner_(base::ThreadTaskRunnerHandle::Get()) {
    network_state_handler_->AddObserver(this, FROM_HERE);
  }
  
  TetherNetworkDisconnectionHandler::~TetherNetworkDisconnectionHandler() {
    network_state_handler_->RemoveObserver(this, FROM_HERE);
  }
  
  void TetherNetworkDisconnectionHandler::NetworkConnectionStateChanged(
      const NetworkState* network) {
    // Only handle network connection state changes which indicate that the
    // underlying Wi-Fi network for a Tether connection has been disconnected.
    if (network->guid() != active_host_->GetWifiNetworkGuid() ||
        network->IsConnectingOrConnected()) {
      return;
    }
  
    // Handle disconnection as part of a new task. Posting a task here ensures
    // that processing the disconnection is done after other
    // NetworkStateHandlerObservers are finished running. Processing the
    // disconnection immediately can cause crashes; see https://crbug.com/800370.
    task_runner_->PostTask(
        FROM_HERE, base::BindOnce(&TetherNetworkDisconnectionHandler::
                                      HandleActiveWifiNetworkDisconnection,
                                  weak_ptr_factory_.GetWeakPtr(), network->guid(),
                                  network->path()));
  }
  
  void TetherNetworkDisconnectionHandler::HandleActiveWifiNetworkDisconnection(
      const std::string& network_guid,
      const std::string& network_path) {
    PA_LOG(WARNING) << "Connection to active host (Wi-Fi network GUID "
                    << network_guid << ") has been lost.";
  
    // Check if Wi-Fi is enabled; if it is, this indicates that the connection
    // to the Tether host dropped. If it isn't, then the event of Wi-Fi being
    // disabled caused the connection to end.
    tether_session_completion_logger_->RecordTetherSessionCompletion(
        network_state_handler_->IsTechnologyEnabled(NetworkTypePattern::WiFi())
            ? TetherSessionCompletionLogger::SessionCompletionReason::
                  CONNECTION_DROPPED
            : TetherSessionCompletionLogger::SessionCompletionReason::
                  WIFI_DISABLED);
  
    network_configuration_remover_->RemoveNetworkConfigurationByPath(
        network_path);
  
    // Send a DisconnectTetheringRequest to the tether host so that it can shut
    // down its Wi-Fi hotspot if it is no longer in use.
    disconnect_tethering_request_sender_->SendDisconnectRequestToDevice(
        active_host_->GetActiveHostDeviceId());
  
    active_host_->SetActiveHostDisconnected();
  }
  
  void TetherNetworkDisconnectionHandler::SetTaskRunnerForTesting(
      scoped_refptr<base::TaskRunner> test_task_runner) {
    task_runner_ = test_task_runner;
  }
  
  }  // namespace tether
  
  }  // namespace chromeos
  