Substituting legacy protocol with uWeave protocol

components/proximity_auth/ble/bluetooth_low_energy_weave_client_connection.cc

+// Copyright 2016 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 "components/proximity_auth/ble/bluetooth_low_energy_weave_client_connection.h"
+
+#include <utility>
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/task_runner.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "components/proximity_auth/bluetooth_throttler.h"
+#include "components/proximity_auth/connection_finder.h"
+#include "components/proximity_auth/logging/logging.h"
+#include "components/proximity_auth/wire_message.h"
+#include "device/bluetooth/bluetooth_gatt_connection.h"
+
+using device::BluetoothAdapter;
+using device::BluetoothDevice;
+using device::BluetoothGattConnection;
+using device::BluetoothRemoteGattService;
+using device::BluetoothRemoteGattCharacteristic;
+using device::BluetoothGattNotifySession;
+using device::BluetoothUUID;
+
+namespace proximity_auth {
+namespace weave {
+namespace {
+
+typedef BluetoothLowEnergyWeavePacketReceiver::State ReceiverState;
+
+const int kDefaultMessageCounter = 0;
+
+// The UUID of the TX characteristic used to transmit data to the server.
+const char kTXCharacteristicUUID[] = "00000100-0004-1000-8000-001A11000101";
+
+// The UUID of the RX characteristic used to receive data from the server.
+const char kRXCharacteristicUUID[] = "00000100-0004-1000-8000-001A11000102";
+
+}  // namespace
+
+BluetoothLowEnergyWeaveClientConnection::
+    BluetoothLowEnergyWeaveClientConnection(
+        const RemoteDevice& device,
+        scoped_refptr<device::BluetoothAdapter> adapter,
+        const BluetoothUUID remote_service_uuid,
+        BluetoothThrottler* bluetooth_throttler,
+        int max_number_of_write_attempts)
+    : Connection(device),
+      adapter_(adapter),
+      remote_service_({remote_service_uuid, ""}),
+      packet_generator_(
+          BluetoothLowEnergyWeavePacketGenerator::Factory::NewInstance()),
+      packet_receiver_(
+          BluetoothLowEnergyWeavePacketReceiver::Factory::NewInstance(
+              BluetoothLowEnergyWeavePacketReceiver::ReceiverType::CLIENT)),
+      tx_characteristic_({BluetoothUUID(kTXCharacteristicUUID), ""}),
+      rx_characteristic_({BluetoothUUID(kRXCharacteristicUUID), ""}),
+      bluetooth_throttler_(bluetooth_throttler),
+      task_runner_(base::ThreadTaskRunnerHandle::Get()),
+      sub_status_(SubStatus::DISCONNECTED),
+      write_remote_characteristic_pending_(false),
+      next_message_counter_to_use_(kDefaultMessageCounter + 1),
+      max_number_of_write_attempts_(max_number_of_write_attempts),
+      weak_ptr_factory_(this) {
+  DCHECK(adapter_);
+  DCHECK(adapter_->IsInitialized());
+
+  adapter_->AddObserver(this);
+}
+
+BluetoothLowEnergyWeaveClientConnection::
+    ~BluetoothLowEnergyWeaveClientConnection() {
+  // Since the destructor can be called at anytime, it would be unwise to send a
+  // connection since we might not be connected at all.

[Tim Song, 2016/07/21 20:49:34]

"it would be unwise to send a connection"

What does "send a connection" refer to here?

[jingxuy, 2016/07/21 21:30:34]

Done.

+  DestroyConnection();
+
+  if (adapter_) {
+    adapter_->RemoveObserver(this);
+    adapter_ = NULL;
+  }
+}
+
+void BluetoothLowEnergyWeaveClientConnection::Connect() {
+  DCHECK(sub_status() == SubStatus::DISCONNECTED);
+
+  SetSubStatus(SubStatus::WAITING_GATT_CONNECTION);
+  base::TimeDelta throttler_delay = bluetooth_throttler_->GetDelay();
+  PA_LOG(INFO) << "Connecting in  " << throttler_delay;
+
+  start_time_ = base::TimeTicks::Now();
+
+  // If necessary, wait to create a new GATT connection.
+  //
+  // Avoid creating a new GATT connection immediately after a given device was
+  // disconnected. This is a workaround for crbug.com/508919.
+  if (!throttler_delay.is_zero()) {
+    task_runner_->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(
+            &BluetoothLowEnergyWeaveClientConnection::CreateGattConnection,
+            weak_ptr_factory_.GetWeakPtr()),
+        throttler_delay);
+    return;
+  }
+
+  CreateGattConnection();
+}
+
+void BluetoothLowEnergyWeaveClientConnection::CreateGattConnection() {
+  DCHECK(sub_status() == SubStatus::WAITING_GATT_CONNECTION);
+
+  BluetoothDevice* remote_device = GetRemoteDevice();
+  if (remote_device) {

[Tim Song, 2016/07/21 20:49:35]

If remote_device == null, we should call DestroyConnection()

[jingxuy, 2016/07/21 21:30:34]

DestroyConnection destroys a gatt connection. so if it's never established,
there is nothing to destroy.

[Tim Song, 2016/07/22 00:52:50]

It also calls SetStatus(DISCONNECTED), which would inform the observers
registered with the connection.

[jingxuy, 2016/07/22 17:14:59]

Done.

+    PA_LOG(INFO) << "Creating GATT connection with "
+                 << remote_device->GetAddress();
+
+    remote_device->CreateGattConnection(
+        base::Bind(
+            &BluetoothLowEnergyWeaveClientConnection::OnGattConnectionCreated,
+            weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&BluetoothLowEnergyWeaveClientConnection::
+                       OnCreateGattConnectionError,
+                   weak_ptr_factory_.GetWeakPtr()));
+  }
+}
+
+void BluetoothLowEnergyWeaveClientConnection::Disconnect() {
+  if (sub_status_ == SubStatus::CONNECTED) {
+    // Friendly disconnect by sending a connection close and then destroy the
+    // the connection once the connection close has been sent.
+    WriteRequest request(packet_generator_->CreateConnectionClose(
+                             ReasonForClose::CLOSE_WITHOUT_ERROR),
+                         WriteRequestType::CONNECTION_CLOSE);
+    WriteRemoteCharacteristic(request);
+  } else {
+    DestroyConnection();
+  }
+}
+
+void BluetoothLowEnergyWeaveClientConnection::DestroyConnection() {
+  if (sub_status() != SubStatus::DISCONNECTED) {
+    weak_ptr_factory_.InvalidateWeakPtrs();
+    StopNotifySession();
+    characteristic_finder_.reset();
+    if (gatt_connection_) {
+      PA_LOG(INFO) << "Disconnect from device "
+                   << gatt_connection_->GetDeviceAddress();
+
+      // Destroying BluetoothGattConnection also disconnects it.
+      gatt_connection_.reset();
+    }
+
+    // Only transition to the DISCONNECTED state after perfoming all necessary
+    // operations. Otherwise, it'll trigger observers that can pontentially
+    // destroy the current instance (causing a crash).
+    SetSubStatus(SubStatus::DISCONNECTED);
+  }
+}
+
+void BluetoothLowEnergyWeaveClientConnection::SetSubStatus(
+    SubStatus new_sub_status) {
+  sub_status_ = new_sub_status;
+
+  // Sets the status of parent class proximity_auth::Connection accordingly.
+  if (new_sub_status == SubStatus::CONNECTED) {
+    SetStatus(Status::CONNECTED);
+  } else if (new_sub_status == SubStatus::DISCONNECTED) {
+    SetStatus(Status::DISCONNECTED);
+  } else {
+    SetStatus(Status::IN_PROGRESS);
+  }
+}
+
+void BluetoothLowEnergyWeaveClientConnection::SetTaskRunnerForTesting(
+    scoped_refptr<base::TaskRunner> task_runner) {
+  task_runner_ = task_runner;
+}
+
+void BluetoothLowEnergyWeaveClientConnection::SendMessageImpl(
+    std::unique_ptr<WireMessage> message) {
+  PA_LOG(INFO) << "Sending message " << message->Serialize();
+  std::string serialized_msg = message->Serialize();
+
+  int current_message_counter = next_message_counter_to_use_;
+  next_message_counter_to_use_++;
+
+  // Transfer ownership of message to the unique_ptr in map_to_message_,
+  // message will contain nullptr.
+  map_to_message_.insert(std::pair<int, std::unique_ptr<WireMessage>>(
+      current_message_counter, std::move(message)));
+
+  std::vector<Packet> packets =
+      packet_generator_->EncodeDataMessage(serialized_msg);
+
+  for (uint32_t i = 0; i < packets.size(); ++i) {
+    WriteRequestType request_type = (i == packets.size() - 1)
+                                        ? WriteRequestType::MESSAGE_COMPLETE
+                                        : WriteRequestType::REGULAR;
+    WriteRequest request =
+        WriteRequest(packets[i], request_type, current_message_counter);
+    WriteRemoteCharacteristic(request);
+  }
+}
+
+// Changes in the GATT connection with the remote device should be observed
+// here. If the GATT connection is dropped, we should call DestroyConnection()
+// anyway, so the object can notify its observers.
+void BluetoothLowEnergyWeaveClientConnection::DeviceChanged(
+    BluetoothAdapter* adapter,
+    BluetoothDevice* device) {
+  DCHECK(device);
+  if (sub_status() == SubStatus::DISCONNECTED ||
+      device->GetAddress() != GetDeviceAddress())
+    return;
+
+  if (sub_status() != SubStatus::WAITING_GATT_CONNECTION &&
+      !device->IsConnected()) {
+    PA_LOG(INFO) << "GATT connection dropped " << GetDeviceAddress()
+                 << "\ndevice connected: " << device->IsConnected()
+                 << "\ngatt connection: "
+                 << (gatt_connection_ ? gatt_connection_->IsConnected()
+                                      : false);
+    DestroyConnection();
+  }
+}
+
+void BluetoothLowEnergyWeaveClientConnection::DeviceRemoved(
+    BluetoothAdapter* adapter,
+    BluetoothDevice* device) {
+  DCHECK(device);
+  if (sub_status_ == SubStatus::DISCONNECTED ||
+      device->GetAddress() != GetDeviceAddress())
+    return;
+
+  PA_LOG(INFO) << "Device removed " << GetDeviceAddress();
+  DestroyConnection();
+}
+
+void BluetoothLowEnergyWeaveClientConnection::GattCharacteristicValueChanged(
+    BluetoothAdapter* adapter,
+    BluetoothRemoteGattCharacteristic* characteristic,
+    const Packet& value) {
+  DCHECK_EQ(adapter, adapter_.get());
+  if (sub_status() != SubStatus::WAITING_CONNECTION_RESPONSE &&
+      sub_status() != SubStatus::CONNECTED)
+    return;
+
+  PA_LOG(INFO) << "Characteristic value changed: "
+               << characteristic->GetUUID().canonical_value();
+
+  if (characteristic->GetIdentifier() == rx_characteristic_.id) {
+    ReceiverState state = packet_receiver_->ReceivePacket(value);
+
+    PA_LOG(INFO) << "\nReceiver State: " << state;
+    switch (state) {
+      case ReceiverState::DATA_READY:
+        OnBytesReceived(packet_receiver_->GetDataMessage());
+        break;
+      case ReceiverState::CONNECTION_CLOSED:
+        PA_LOG(ERROR) << "Connection closed due to: " << GetReasonForClose();
+        DestroyConnection();
+        break;
+      case ReceiverState::ERROR_DETECTED:
+        OnPacketReceiverError();
+        break;
+      case ReceiverState::WAITING:
+        // Receiver state should have changed from CONNECTING to WAITING if
+        // a proper connection response had been received.
+        // The max packet size selected from the connection response will be
+        // used to generate future data packets.
+        packet_generator_->SetMaxPacketSize(
+            packet_receiver_->GetMaxPacketSize());
+        DCHECK(sub_status() == SubStatus::WAITING_CONNECTION_RESPONSE);
+        CompleteConnection();
+        break;
+      case ReceiverState::RECEIVING_DATA:
+        // Normal in between states, so do nothing.
+        break;
+      default:
+        NOTREACHED();
+    }
+  }
+}
+
+BluetoothLowEnergyWeaveClientConnection::WriteRequest::WriteRequest(

[Tim Song, 2016/07/21 20:49:35]

nit: move these WriteRequest definitions below all the parent class methods.

[jingxuy, 2016/07/21 21:30:34]

Done.

+    const Packet& val,
+    WriteRequestType request_type,
+    int message_counter)
+    : value(val),
+      request_type(request_type),
+      message_counter(message_counter),
+      number_of_failed_attempts(0) {}
+
+BluetoothLowEnergyWeaveClientConnection::WriteRequest::WriteRequest(
+    const Packet& val,
+    WriteRequestType request_type)
+    : value(val),
+      request_type(request_type),
+      message_counter(kDefaultMessageCounter),
+      number_of_failed_attempts(0) {}
+
+BluetoothLowEnergyWeaveClientConnection::WriteRequest::WriteRequest(
+    const WriteRequest& other) = default;
+
+BluetoothLowEnergyWeaveClientConnection::WriteRequest::~WriteRequest() {}
+
+void BluetoothLowEnergyWeaveClientConnection::CompleteConnection() {
+  PA_LOG(INFO) << "Connection completed. Time elapsed: "
+               << base::TimeTicks::Now() - start_time_;
+  SetSubStatus(SubStatus::CONNECTED);
+}
+
+void BluetoothLowEnergyWeaveClientConnection::OnCreateGattConnectionError(
+    device::BluetoothDevice::ConnectErrorCode error_code) {
+  DCHECK(sub_status_ == SubStatus::WAITING_GATT_CONNECTION);
+  PA_LOG(WARNING) << "Error creating GATT connection to "
+                  << remote_device().bluetooth_address
+                  << "error code: " << error_code;

[Tim Song, 2016/07/21 20:49:34]

nit: extra space or comma before "error code: "

[jingxuy, 2016/07/21 21:30:34]

Done.

+  DestroyConnection();
+}
+
+void BluetoothLowEnergyWeaveClientConnection::OnGattConnectionCreated(
+    std::unique_ptr<device::BluetoothGattConnection> gatt_connection) {
+  DCHECK(sub_status() == SubStatus::WAITING_GATT_CONNECTION);
+  PA_LOG(INFO) << "GATT connection with " << gatt_connection->GetDeviceAddress()
+               << " created.";
+  PrintTimeElapsed();
+
+  // Informing |bluetooth_trottler_| a new connection was established.
+  bluetooth_throttler_->OnConnection(this);
+
+  gatt_connection_ = std::move(gatt_connection);

[Tim Song, 2016/07/21 20:49:34]

nit: You don't need the std::move() call. By default, unique_ptrs should have
move semantics for assignment.

[jingxuy, 2016/07/21 21:30:34]

Done.

+  SetSubStatus(SubStatus::WAITING_CHARACTERISTICS);
+  characteristic_finder_.reset(CreateCharacteristicsFinder(
+      base::Bind(
+          &BluetoothLowEnergyWeaveClientConnection::OnCharacteristicsFound,
+          weak_ptr_factory_.GetWeakPtr()),
+      base::Bind(&BluetoothLowEnergyWeaveClientConnection::
+                     OnCharacteristicsFinderError,
+                 weak_ptr_factory_.GetWeakPtr())));
+}
+
+BluetoothLowEnergyCharacteristicsFinder*
+BluetoothLowEnergyWeaveClientConnection::CreateCharacteristicsFinder(
+    const BluetoothLowEnergyCharacteristicsFinder::SuccessCallback&
+        success_callback,
+    const BluetoothLowEnergyCharacteristicsFinder::ErrorCallback&
+        error_callback) {
+  return new BluetoothLowEnergyCharacteristicsFinder(
+      adapter_, GetRemoteDevice(), remote_service_, tx_characteristic_,
+      rx_characteristic_, success_callback, error_callback);
+}
+
+void BluetoothLowEnergyWeaveClientConnection::OnCharacteristicsFound(
+    const RemoteAttribute& service,
+    const RemoteAttribute& tx_characteristic,
+    const RemoteAttribute& rx_characteristic) {
+  PA_LOG(INFO) << "Remote chacteristics found.";
+  PrintTimeElapsed();
+
+  DCHECK(sub_status() == SubStatus::WAITING_CHARACTERISTICS);
+  remote_service_ = service;
+  tx_characteristic_ = tx_characteristic;
+  rx_characteristic_ = rx_characteristic;
+
+  SetSubStatus(SubStatus::CHARACTERISTICS_FOUND);
+  StartNotifySession();
+}
+
+void BluetoothLowEnergyWeaveClientConnection::OnCharacteristicsFinderError(
+    const RemoteAttribute& tx_characteristic,
+    const RemoteAttribute& rx_characteristic) {
+  DCHECK(sub_status() == SubStatus::WAITING_CHARACTERISTICS);
+  PA_LOG(WARNING) << "Connection error, missing characteristics for SmartLock "
+                     "service.\n"
+                  << (tx_characteristic.id.empty()

[Tim Song, 2016/07/21 20:49:35]

nit: put new lines or spaces between each characteristic.

[jingxuy, 2016/07/21 21:30:33]

Done.

+                          ? tx_characteristic.uuid.canonical_value()
+                          : "")
+                  << (rx_characteristic.id.empty()
+                          ? ", " + rx_characteristic.uuid.canonical_value()
+                          : "")
+                  << " not found.";
+
+  DestroyConnection();
+}
+
+void BluetoothLowEnergyWeaveClientConnection::StartNotifySession() {
+  if (sub_status() == SubStatus::CHARACTERISTICS_FOUND) {

[Tim Song, 2016/07/21 20:49:34]

DCHECK() this state instead. Can StartNotifySession() be called in any other
case?

[jingxuy, 2016/07/21 21:30:34]

Done.

+    BluetoothRemoteGattCharacteristic* characteristic =
+        GetGattCharacteristic(rx_characteristic_.id);
+    DCHECK(characteristic);

[Tim Song, 2016/07/21 20:49:34]

nit: might as well do a full CHECK here, as we're dereferencing the pointer
right after.

[jingxuy, 2016/07/21 21:30:34]

A lot of your comments are on legacy code. Sorry I didn't look too closely
through them. But done.

+
+    // This is a workaround for crbug.com/507325. If |characteristic| is already
+    // notifying |characteristic->StartNotifySession()| will fail with
+    // GATT_ERROR_FAILED.
+    if (characteristic->IsNotifying()) {
+      PA_LOG(INFO) << characteristic->GetUUID().canonical_value()
+                   << " already notifying.";
+      SetSubStatus(SubStatus::NOTIFY_SESSION_READY);
+      SendConnectionRequest();
+      return;
+    }
+
+    SetSubStatus(SubStatus::WAITING_NOTIFY_SESSION);
+    characteristic->StartNotifySession(
+        base::Bind(
+            &BluetoothLowEnergyWeaveClientConnection::OnNotifySessionStarted,
+            weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(
+            &BluetoothLowEnergyWeaveClientConnection::OnNotifySessionError,
+            weak_ptr_factory_.GetWeakPtr()));
+  }
+}
+
+void BluetoothLowEnergyWeaveClientConnection::OnNotifySessionStarted(
+    std::unique_ptr<BluetoothGattNotifySession> notify_session) {
+  DCHECK(sub_status() == SubStatus::WAITING_NOTIFY_SESSION);
+  PA_LOG(INFO) << "Notification session started "
+               << notify_session->GetCharacteristicIdentifier();
+  PrintTimeElapsed();
+
+  SetSubStatus(SubStatus::NOTIFY_SESSION_READY);
+  notify_session_ = std::move(notify_session);

[Tim Song, 2016/07/21 20:49:35]

nit: no need for std::move

[jingxuy, 2016/07/21 21:30:34]

also legacy code. Done.

[jingxuy, 2016/07/22 17:14:59]

Also wasn't thinking clearly yesterday. On second thought upon compilation
failures. I think you need the std::move.

Check out examples in:
http://en.cppreference.com/w/cpp/memory/unique_ptr/operator%3D

[Tim Song, 2016/07/22 18:41:34]

Ah I see, I was thinking of scoped_ptr, which has these semantics.

+
+  SendConnectionRequest();
+}
+
+void BluetoothLowEnergyWeaveClientConnection::OnNotifySessionError(
+    BluetoothRemoteGattService::GattErrorCode error) {
+  DCHECK(sub_status() == SubStatus::WAITING_NOTIFY_SESSION);
+  PA_LOG(WARNING) << "Error starting notification session: " << error;
+  DestroyConnection();
+}
+
+void BluetoothLowEnergyWeaveClientConnection::StopNotifySession() {
+  if (notify_session_) {
+    notify_session_->Stop(base::Bind(&base::DoNothing));
+    notify_session_.reset();
+  }
+}
+
+void BluetoothLowEnergyWeaveClientConnection::SendConnectionRequest() {
+  if (sub_status() == SubStatus::NOTIFY_SESSION_READY) {
+    PA_LOG(INFO) << "Sending connection request to the server";
+    SetSubStatus(SubStatus::WAITING_CONNECTION_RESPONSE);
+
+    WriteRequest write_request =
+        WriteRequest(packet_generator_->CreateConnectionRequest(),
+                     WriteRequestType::CONNECTION_REQUEST);
+
+    WriteRemoteCharacteristic(write_request);
+  }
+}
+
+void BluetoothLowEnergyWeaveClientConnection::WriteRemoteCharacteristic(
+    const WriteRequest& request) {
+  write_requests_queue_.push(request);
+  ProcessNextWriteRequest();
+}
+
+void BluetoothLowEnergyWeaveClientConnection::ProcessNextWriteRequest() {
+  BluetoothRemoteGattCharacteristic* characteristic =
+      GetGattCharacteristic(tx_characteristic_.id);
+  if (!write_requests_queue_.empty() && !write_remote_characteristic_pending_ &&
+      characteristic) {
+    write_remote_characteristic_pending_ = true;
+    WriteRequest next_request = write_requests_queue_.front();
+
+    PA_LOG(INFO) << "Writing characteristic...";

[Tim Song, 2016/07/21 20:49:35]

nit: it would be nice to log the number of bytes written.

[jingxuy, 2016/07/21 21:30:34]

Done.

+    characteristic->WriteRemoteCharacteristic(
+        next_request.value,
+        base::Bind(&BluetoothLowEnergyWeaveClientConnection::
+                       OnRemoteCharacteristicWritten,
+                   weak_ptr_factory_.GetWeakPtr(), next_request.request_type,
+                   next_request.message_counter),
+        base::Bind(&BluetoothLowEnergyWeaveClientConnection::
+                       OnWriteRemoteCharacteristicError,
+                   weak_ptr_factory_.GetWeakPtr(), next_request.request_type,
+                   next_request.message_counter));
+  }
+}
+
+void BluetoothLowEnergyWeaveClientConnection::OnRemoteCharacteristicWritten(
+    WriteRequestType request_type,
+    int message_counter) {
+  PA_LOG(INFO) << "Characteristic written.";
+
+  switch (request_type) {
+    case WriteRequestType::REGULAR:
+    case WriteRequestType::CONNECTION_REQUEST:
+      break;
+    case WriteRequestType::MESSAGE_COMPLETE:
+      OnDidSendMessage(*map_to_message_[message_counter], true);
+      map_to_message_.erase(message_counter);
+      break;
+    case WriteRequestType::CONNECTION_CLOSE:
+      DestroyConnection();
+      break;
+    default:
+      NOTREACHED();
+  }
+
+  // Removes the top of queue (already processed) and process the next request.
+  DCHECK(!write_requests_queue_.empty());
+  write_requests_queue_.pop();
+  write_remote_characteristic_pending_ = false;
+  ProcessNextWriteRequest();
+}
+
+void BluetoothLowEnergyWeaveClientConnection::OnWriteRemoteCharacteristicError(
+    WriteRequestType request_type,
+    int message_counter,
+    BluetoothRemoteGattService::GattErrorCode error) {
+  PA_LOG(WARNING) << "Error " << error << " writing characteristic: "
+                  << tx_characteristic_.uuid.canonical_value();
+
+  write_remote_characteristic_pending_ = false;
+
+  // Increases the number of failed attempts and retry.
+  DCHECK(!write_requests_queue_.empty());
+  if (++write_requests_queue_.front().number_of_failed_attempts >=
+      max_number_of_write_attempts_) {
+    switch (request_type) {
+      case WriteRequestType::REGULAR:
+      case WriteRequestType::MESSAGE_COMPLETE:
+        OnDidSendMessage(*map_to_message_[message_counter], false);
+        map_to_message_.erase(message_counter);
+        break;
+      case WriteRequestType::CONNECTION_CLOSE:
+      case WriteRequestType::CONNECTION_REQUEST:
+        break;
+      default:
+        NOTREACHED();
+    }
+
+    // If the previous write failed that many times, probably can't write a
+    // connection close either, so just destroy the connection.
+    DestroyConnection();
+  } else {
+    ProcessNextWriteRequest();
+  }
+}
+
+void BluetoothLowEnergyWeaveClientConnection::OnPacketReceiverError() {
+  PA_LOG(ERROR) << "Received erroneous packet. Closing connection.";
+
+  WriteRequest request(packet_generator_->CreateConnectionClose(
+                           packet_receiver_->GetReasonToClose()),
+                       WriteRequestType::CONNECTION_CLOSE);
+
+  // Skip all other writes that's not in progress.
+
+  // C++ queue does not have a clear method.
+  // According to stackoverflow
+  // "http://stackoverflow.com/questions/709146/how-do-i-clear-the-stdqueue-
+  //  efficiently"
+  std::queue<WriteRequest> empty;
+  std::swap(write_requests_queue_, empty);
+
+  if (write_remote_characteristic_pending_) {
+    // Add the in progress write back to the queue.
+    write_requests_queue_.push(empty.front());
+  }
+
+  WriteRemoteCharacteristic(request);
+}
+
+void BluetoothLowEnergyWeaveClientConnection::PrintTimeElapsed() {
+  PA_LOG(INFO) << "Time elapsed: " << base::TimeTicks::Now() - start_time_;
+}
+
+std::string BluetoothLowEnergyWeaveClientConnection::GetDeviceAddress() {
+  // When the remote device is connected we should rely on the address given by
+  // |gatt_connection_|. As the device address may change if the device is
+  // paired. The address in |gatt_connection_| is automatically updated in this
+  // case.
+  return gatt_connection_ ? gatt_connection_->GetDeviceAddress()
+                          : remote_device().bluetooth_address;
+}
+
+BluetoothDevice* BluetoothLowEnergyWeaveClientConnection::GetRemoteDevice() {
+  // It's not possible to simply use
+  // |adapter_->GetDevice(GetDeviceAddress())| to find the device with MAC
+  // address |GetDeviceAddress()|. For paired devices,
+  // BluetoothAdapter::GetDevice(XXX) searches for the temporary MAC address
+  // XXX, whereas |GetDeviceAddress()| is the real MAC address. This is a
+  // bug in the way device::BluetoothAdapter is storing the devices (see
+  // crbug.com/497841).
+  std::vector<BluetoothDevice*> devices = adapter_->GetDevices();
+  for (const auto& device : devices) {
+    if (device->GetAddress() == GetDeviceAddress())
+      return device;
+  }
+
+  return nullptr;
+}
+
+BluetoothRemoteGattService*
+BluetoothLowEnergyWeaveClientConnection::GetRemoteService() {
+  BluetoothDevice* remote_device = GetRemoteDevice();
+  if (!remote_device) {
+    PA_LOG(WARNING) << "Remote device not found.";
+    return NULL;
+  }
+  if (remote_service_.id.empty()) {
+    std::vector<BluetoothRemoteGattService*> services =
+        remote_device->GetGattServices();
+    for (const auto& service : services)
+      if (service->GetUUID() == remote_service_.uuid) {
+        remote_service_.id = service->GetIdentifier();
+        break;
+      }
+  }
+  return remote_device->GetGattService(remote_service_.id);
+}
+
+BluetoothRemoteGattCharacteristic*
+BluetoothLowEnergyWeaveClientConnection::GetGattCharacteristic(
+    const std::string& gatt_characteristic) {
+  BluetoothRemoteGattService* remote_service = GetRemoteService();
+  if (!remote_service) {
+    PA_LOG(WARNING) << "Remote service not found.";
+    return NULL;
+  }
+  return remote_service->GetCharacteristic(gatt_characteristic);
+}
+
+std::string BluetoothLowEnergyWeaveClientConnection::GetReasonForClose() {
+  switch (packet_receiver_->GetReasonForClose()) {
+    case ReasonForClose::CLOSE_WITHOUT_ERROR:
+      return "CLOSE_WITHOUT_ERROR";
+    case ReasonForClose::UNKNOWN_ERROR:
+      return "UNKNOWN_ERROR";
+    case ReasonForClose::NO_COMMON_VERSION_SUPPORTED:
+      return "NO_COMMON_VERSION_SUPPORTED";
+    case ReasonForClose::RECEIVED_PACKET_OUT_OF_SEQUENCE:
+      return "RECEIVED_PACKET_OUT_OF_SEQUENCE";
+    case ReasonForClose::APPLICATION_ERROR:
+      return "APPLICATION_ERROR";
+    default:
+      NOTREACHED();
+  }
+}
+
+}  // namespace weave
+
+}  // namespace proximity_auth