Bluetooth low energy connection.

components/proximity_auth/ble/bluetooth_low_energy_connection.h

+// Copyright 2015 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 COMPONENTS_PROXIMITY_AUTH_BLUETOOTH_LOW_ENERGY_CONNECTION_H
+#define COMPONENTS_PROXIMITY_AUTH_BLUETOOTH_LOW_ENERGY_CONNECTION_H
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "components/proximity_auth/ble/fake_wire_message.h"
+#include "components/proximity_auth/connection.h"
+#include "device/bluetooth/bluetooth_adapter.h"
+#include "device/bluetooth/bluetooth_device.h"
+#include "device/bluetooth/bluetooth_gatt_characteristic.h"
+#include "device/bluetooth/bluetooth_gatt_notify_session.h"
+#include "device/bluetooth/bluetooth_uuid.h"
+
+namespace proximity_auth {
+
+class BluetoothLowEnergyConnection : public Connection,

[msarda, 2015/05/05 11:56:14]

Comment this class. It should ideally describe the strategy used to cut down
messages that are sent over BLE.

[sacomoto, 2015/05/06 13:47:58]

Done.

+                                     public device::BluetoothAdapter::Observer {
+ public:
+  BluetoothLowEnergyConnection(
+      const RemoteDevice& remote_device,
+      scoped_refptr<device::BluetoothAdapter> adapter,
+      device::BluetoothUUID remote_service_uuid,
+      scoped_ptr<device::BluetoothGattConnection> gatt_connection);
+
+  ~BluetoothLowEnergyConnection();
+
+  void Connect();

[msarda, 2015/05/05 11:56:14]

Are these methods overriding Connection? If so, then they should be 
void Connect() override;

[sacomoto, 2015/05/06 13:47:58]

Done.

+
+  void Disconnect();
+
+ protected:
+  // proximity_auth::Connection
+  void SendMessageImpl(scoped_ptr<WireMessage> message) override;
+  scoped_ptr<WireMessage> DeserializeWireMessage(
+      bool* is_incomplete_message) override;
+
+  // device::BluetoothAdaptor::Observer
+  void DeviceRemoved(device::BluetoothAdapter* adapter,
+                     device::BluetoothDevice* device) override;
+  void GattDiscoveryCompleteForService(
+      device::BluetoothAdapter* adapter,
+      device::BluetoothGattService* service) override;
+  void GattCharacteristicAdded(
+      device::BluetoothAdapter* adapter,
+      device::BluetoothGattCharacteristic* characteristic) override;
+  void GattCharacteristicValueChanged(
+      device::BluetoothAdapter* adapter,
+      device::BluetoothGattCharacteristic* characteristic,
+      const std::vector<uint8>& value) override;
+
+ private:
+  std::string remote_device_address() {

[msarda, 2015/05/05 11:56:14]

This is not a trivial method. It should be GetRemoteDeviceAddress and its
implementation should be in the .cc file.

[msarda, 2015/05/05 11:56:14]

Change return type to const std::string&

[sacomoto, 2015/05/06 13:47:58]

Done.

[sacomoto, 2015/05/06 13:47:58]

Done.

+    return remote_device().bluetooth_address;
+  }
+
+  // Send a invite to connect signal (defined in Socketeer library) to the

[msarda, 2015/05/05 11:56:14]

s/Send a invite/Sends an invite

[msarda, 2015/05/05 11:56:14]

Remote reference to Socketeer library. That is not public and people looking at
this code review will not understand what that means.

[sacomoto, 2015/05/06 13:47:58]

Done.

[sacomoto, 2015/05/06 13:47:58]

Done.

+  // central.

[msarda, 2015/05/05 11:56:14]

central? Should this be peripheral?

[sacomoto, 2015/05/06 13:47:58]

Done.

+  void SendInviteToConnectSignal();
+
+  // Called when there is an error writing the remote characteristic

[msarda, 2015/05/05 11:56:14]

s/writing the/writing to the

[sacomoto, 2015/05/06 13:47:58]

Done.

+  // |to_peripheral_char_|.
+  void OnWriteRemoteCharacteristicError(
+      device::BluetoothGattService::GattErrorCode error);
+
+  // Handles the discovery of a new characteristic.
+  void HandleCharacteristicUpdate(
+      device::BluetoothGattCharacteristic* characteristic);
+
+  // The connection is complete when: (i) |to_peripheral_char_| and

[msarda, 2015/05/05 11:56:14]

Maybe move (i) and (ii) on different lines (like bullet points). I find it more
readable.

[sacomoto, 2015/05/06 13:47:58]

Done.

+  // |from_peripheral_char_| were found, and (ii) |notify_session_| was set for
+  // |from_peripheral_char_|. This function verifies if the connection is
+  // complete and updates the status accordingly. There are two asyncronous
+  // events that can cause the connection to be completed: (i) a new
+  // characteristic is discovered (HandleCharacteristicUpdate) or (ii) a new
+  // notify session is started (OnNotifySessionStarted).
+  void CompleteConnection();
+
+  // Starts a notify session for |from_peripheral_char_|.
+  void StartNotifySession();
+
+  // Called when there is an error starting a notification session for
+  // |from_peripheral_char_|.

[msarda, 2015/05/05 11:56:14]

s/|from_peripheral_char_|/|from_peripheral_char_| characteristic.

[sacomoto, 2015/05/06 13:47:58]

Done.

+  void OnNotifySessionError(device::BluetoothGattService::GattErrorCode);
+
+  // Called when a notification session is successfully started for
+  // |from_peripheral_char_|.

[msarda, 2015/05/05 11:56:14]

Ditto.

[sacomoto, 2015/05/06 13:47:58]

Done.

+  void OnNotifySessionStarted(
+      scoped_ptr<device::BluetoothGattNotifySession> notify_session);
+
+  // Stops |notify_session_|.
+  void StopNotifySession();
+
+  // Updates the value of |has_to_peripheral_char| and
+  // |has_from_peripheral_char|
+  // when for |characteristic| or characteristics in |service|.
+  void UpdateCharacteristicsStatus(
+      device::BluetoothGattCharacteristic* characteristic);
+
+  // Returns the device corresponding to |remote_device_address_|.
+  device::BluetoothDevice* GetRemoteDevice();
+
+  // Returns the service corresponding to |remote_service_uuid_| in the current
+  // device.
+  device::BluetoothGattService* GetRemoteService();
+
+  // Returns the characteristic corresponding to |identifier| in the current
+  // service.
+  device::BluetoothGattCharacteristic* GetGattCharacteristic(
+      const std::string& identifier);
+
+  // The Bluetooth adapter over which the Bluetooth connection will be made.
+  scoped_refptr<device::BluetoothAdapter> adapter_;
+
+  // The uuid of the service it looks for to establish a GattConnection.
+  const device::BluetoothUUID remote_service_uuid_;
+
+  // The identifier of the service corresponding to |remote_service_uuid|.
+  std::string remote_service_id_;
+
+  // The GATT connection with the remote device.
+  scoped_ptr<device::BluetoothGattConnection> connection_;
+
+  // Characteristic used to send data to the remote device in the peripheral
+  // role.
+  const std::string to_peripheral_char_ =

[msarda, 2015/05/05 11:56:14]

Same as for from_peripheral_char_

[sacomoto, 2015/05/06 13:47:59]

Done.

+      "977c6674-1239-4e72-993b-502369b8bb5a";
+
+  // Internal unique identifier for |to_peripheral_char_|.
+  std::string to_peripheral_char_id_;
+
+  // Characteristic used to receive data from the remote device in the
+  // peripheral role.
+  const std::string from_peripheral_char_ =

[msarda, 2015/05/05 11:56:14]

This is a characteristic UUID. This is not clear from its name. Maybe:
s/from_peripheral_char_/from_peripheral_char_characteristic_uuid_.

But the const should just be internal or passed down as an argument in the
constructor.

[msarda, 2015/05/05 11:56:14]

These should be constants received from the outside or defined in an internal
anonymous namespace. We do not initialize them in header files.

[sacomoto, 2015/05/06 13:47:58]

Done.

[sacomoto, 2015/05/06 13:47:58]

Done.

+      "f4b904a2-a030-43b3-98a8-221c536c03cb";
+
+  // Internal unique identifier for |from_peripheral_char_|.
+  std::string from_peripheral_char_id_;
+
+  // Indicates if there is a pending notification session. Used to ensure there
+  // is only one pending notify session.
+  bool notify_session_pending_;
+
+  // The notify session for |from_peripheral_char|.
+  scoped_ptr<device::BluetoothGattNotifySession> notify_session_;
+
+  base::WeakPtrFactory<BluetoothLowEnergyConnection> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(BluetoothLowEnergyConnection);
+};
+
+}  // namespace proximity_auth
+
+#endif  // COMPONENTS_PROXIMITY_AUTH_BLUETOOTH_LOW_ENERGY_CONNECTION_H