[CrOS Tether] Create BleScanner, a class which scan BLE advertisements and identifies nearby device…

chromeos/components/tether/ble_scanner.h

Index: chromeos/components/tether/ble_scanner.h
diff --git a/chromeos/components/tether/ble_scanner.h b/chromeos/components/tether/ble_scanner.h
new file mode 100644
index 0000000000000000000000000000000000000000..9015a66423e948c3ae71035d85db60bf814a21a1
--- /dev/null
+++ b/chromeos/components/tether/ble_scanner.h
@@ -0,0 +1,123 @@
+// 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.
+
+#ifndef CHROMEOS_COMPONENTS_BLE_SCANNER_H_
+#define CHROMEOS_COMPONENTS_BLE_SCANNER_H_
+
+#include <map>
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
+#include "chromeos/components/tether/local_device_data_provider.h"
+#include "components/cryptauth/eid_generator.h"
+#include "device/bluetooth/bluetooth_adapter.h"
+#include "device/bluetooth/bluetooth_adapter_factory.h"
+
+namespace device {
+class BluetoothDevice;
+class BluetoothDiscoverySession;
+}
+
+namespace chromeos {
+
+namespace tether {
+
+class BleScanner : public device::BluetoothAdapter::Observer {
+ public:
+  class Observer {
+   public:
+    virtual void OnReceivedAdvertisementFromDevice(
+        const device::BluetoothDevice* bluetooth_device,
+        cryptauth::RemoteDevice remote_device) = 0;
+  };
+
+  BleScanner(const LocalDeviceDataProvider* local_device_data_provider);
+  ~BleScanner() override;
+
+  bool RegisterScanFilterForDevice(const cryptauth::RemoteDevice& device);
+  bool UnregisterScanFilterForDevice(const cryptauth::RemoteDevice& device);
+
+  bool IsDeviceRegistered(const std::string& device_id);
+
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+  // device::BluetoothAdapter::Observer
+  void AdapterPoweredChanged(device::BluetoothAdapter* adapter,
+                             bool powered) override;
+  void DeviceAdded(device::BluetoothAdapter* adapter,
+                   device::BluetoothDevice* device) override;

[Ryan Hansberry, 2017/01/04 00:01:03]

nit: because there are mixed mentions of RemoteDevices and BluetoothDevices
throughout this class, I think it would moderately improve readability to
clarify all BluetoothDevices as 'bluetooth_device' as opposed to simply
'device'. Otherwise readers can become confused what kind of *Device each
'device' variable is. 

I also personally find it confusing that OnReceivedAdvertisementFromDevice()'s
BluetoothDevice param is 'bluetooth_device', but other methods' BluetoothDevice
params are named 'device'.

[Kyle Horimoto, 2017/01/04 18:35:43]

Done.

+  void DeviceChanged(device::BluetoothAdapter* adapter,
+                     device::BluetoothDevice* device) override;
+
+ private:
+  friend class BleScannerTest;
+
+  class Delegate {
+   public:
+    virtual ~Delegate() {}
+    virtual bool IsBluetoothAdapterAvailable() const = 0;
+    virtual void GetAdapter(
+        const device::BluetoothAdapterFactory::AdapterCallback& callback) = 0;
+    virtual const std::vector<uint8_t>* GetServiceDataForUUID(
+        const device::BluetoothUUID& service_uuid,
+        device::BluetoothDevice* device) = 0;
+  };
+
+  class DelegateImpl : public Delegate {
+   public:
+    DelegateImpl();
+    ~DelegateImpl() override;
+    bool IsBluetoothAdapterAvailable() const override;
+    void GetAdapter(const device::BluetoothAdapterFactory::AdapterCallback&
+                        callback) override;
+    const std::vector<uint8_t>* GetServiceDataForUUID(
+        const device::BluetoothUUID& service_uuid,
+        device::BluetoothDevice* device) override;
+  };
+
+  BleScanner(std::unique_ptr<Delegate> delegate,
+             const cryptauth::EidGenerator* eid_generator,
+             const LocalDeviceDataProvider* local_device_data_provider);
+
+  void UpdateDiscoveryStatus();
+  void InitializeBluetoothAdapter();
+  void OnAdapterInitialized(scoped_refptr<device::BluetoothAdapter> adapter);
+  void StartDiscoverySession();
+  void OnDiscoverySessionStarted(
+      std::unique_ptr<device::BluetoothDiscoverySession> discovery_session);
+  void OnStartDiscoverySessionError();
+  void StopDiscoverySession();
+  void HandleDeviceUpdated(device::BluetoothDevice* device);
+  void CheckForMatchingScanFilters(device::BluetoothDevice* device,
+                                   std::string& service_data);
+
+  std::unique_ptr<Delegate> delegate_;
+
+  // |eid_generator_| and |local_device_data_provider_| are not owned by this
+  // instance and must outlive it.
+  const cryptauth::EidGenerator* eid_generator_;
+  const LocalDeviceDataProvider* local_device_data_provider_;
+
+  bool initializing_adapter_;

[Ryan Hansberry, 2017/01/04 00:01:03]

nit: can you prefix this and 'initializing_discovery_session_' with 'is_'? 

[Kyle Horimoto, 2017/01/04 18:35:43]

Done.

+  scoped_refptr<device::BluetoothAdapter> adapter_;
+
+  bool initializing_discovery_session_;
+  std::unique_ptr<device::BluetoothDiscoverySession> discovery_session_;
+
+  std::vector<cryptauth::RemoteDevice> registered_devices_;

[Ryan Hansberry, 2017/01/04 00:01:04]

Similar comment to my nit above: this would be better as
'registered_remote_devices_'.

[Kyle Horimoto, 2017/01/04 18:35:43]

Done.

+
+  base::ObserverList<Observer> observer_list_;
+
+  base::WeakPtrFactory<BleScanner> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(BleScanner);
+};
+
+}  // namespace tether
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_COMPONENTS_BLE_SCANNER_H_