BluetoothAdapterMac::LowEnergyDeviceUpdated() Implemented

device/bluetooth/bluetooth_adapter_mac.mm

 // 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 "device/bluetooth/bluetooth_adapter_mac.h"
 
 #import <IOBluetooth/objc/IOBluetoothDevice.h>
 #import <IOBluetooth/objc/IOBluetoothHostController.h>
 
 #include <string>
@@ skipping 384 matching lines @@
   // Only notify observers once per device.
   if (devices_.count(device_address))
     return;
 
   devices_[device_address] = new BluetoothClassicDeviceMac(device);
   FOR_EACH_OBSERVER(BluetoothAdapter::Observer,
                     observers_,
                     DeviceAdded(this, devices_[device_address]));
 }
 
-// TODO(krstnmnlsn): Implement method. http://crbug.com/496987.
 void BluetoothAdapterMac::LowEnergyDeviceUpdated(
     CBPeripheral* peripheral,
     NSDictionary* advertisementData,
     int rssi) {
+  std::string device_address =
+      BluetoothLowEnergyDeviceMac::GetPeripheralHashAddress(peripheral);
+  BluetoothDevice*& device_reference = devices_[device_address];

[armansito, 2015/07/15 18:14:42]

Please add a comment here explaining why you're using a reference to a pointer
and why it's OK to use the std::map [] operator before checking if the element
doesn't exist (since the operator will create the map entry if it doesn't
exist). Just explain the assignment done below.

[krstnmnlsn, 2015/07/15 20:38:14]

Done.

+

[armansito, 2015/07/15 18:14:42]

Remove extra space here.

[krstnmnlsn, 2015/07/15 20:38:14]

Done.

+  if (!device_reference) {
+    // A new device has been found.
+    device_reference =
+        new BluetoothLowEnergyDeviceMac(peripheral, advertisementData, rssi);
+    FOR_EACH_OBSERVER(BluetoothAdapter::Observer, observers_,
+                      DeviceAdded(this, device_reference));
+    return;
+  }
+
+  if (static_cast<BluetoothLowEnergyDeviceMac*>(device_reference)
+          ->GetIdentifier() !=
+      BluetoothLowEnergyDeviceMac::GetPeripheralIdentifier(peripheral)) {
+    // Collision, two identifiers map to the same hash address.  With a 48 bit
+    // hash the probability of this occuring with 10,000 devices
+    // simultaneously present is 1e-6 (see
+    // https://en.wikipedia.org/wiki/Birthday_problem#Probability_table).  We
+    // ignore the second device by returning.
+    return;
+  }
+
+  // A device has an update.
+  static_cast<BluetoothLowEnergyDeviceMac*>(device_reference)
+      ->Update(peripheral, advertisementData, rssi);
+  FOR_EACH_OBSERVER(BluetoothAdapter::Observer, observers_,
+                    DeviceChanged(this, device_reference));
 }
 
 void BluetoothAdapterMac::RemoveTimedOutDevices() {
   // Notify observers if any previously seen devices are no longer available,
   // i.e. if they are no longer paired, connected, nor recently discovered via
   // an inquiry.
   std::set<std::string> removed_devices;
   for (DevicesMap::iterator it = devices_.begin(); it != devices_.end(); ++it) {
     BluetoothDevice* device = it->second;
     if (device->IsPaired() || device->IsConnected())
@@ skipping 18 matching lines @@
 }
 
 void BluetoothAdapterMac::AddPairedDevices() {
   // Add any new paired devices.
   for (IOBluetoothDevice* device in [IOBluetoothDevice pairedDevices]) {
     ClassicDeviceAdded(device);
   }
 }
 
 }  // namespace device