Bluetooth: notify user of incoming pairing requests

ash/system/chromeos/bluetooth/bluetooth_notification_controller.h

+// Copyright (c) 2014 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 ASH_SYSTEM_CHROMEOS_BLUETOOTH_BLUETOOTH_NOTIFICATION_CONTROLLER_H_
+#define ASH_SYSTEM_CHROMEOS_BLUETOOTH_BLUETOOTH_NOTIFICATION_CONTROLLER_H_
+
+#include <set>
+
+#include "ash/ash_export.h"
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "base/strings/string16.h"
+#include "device/bluetooth/bluetooth_adapter.h"
+#include "device/bluetooth/bluetooth_device.h"
+
+namespace ash {
+namespace internal {
+
+// The BluetoothNotificationController receives incoming pairing requests from
+// the BluetoothAdapter, and notifications of changes to the adapter state and
+// set of paired devices. It presents incoming pairing requests in the form of
+// rich notifications that the user can interact with to approve the request.
+class ASH_EXPORT BluetoothNotificationController
+    : public device::BluetoothAdapter::Observer,
+      public device::BluetoothDevice::PairingDelegate {
+ public:
+  BluetoothNotificationController();
+  virtual ~BluetoothNotificationController();
+
+  // device::BluetoothAdapter::Observer override.
+  virtual void DeviceAdded(device::BluetoothAdapter* adapter,
+                           device::BluetoothDevice* device) OVERRIDE;
+  virtual void DeviceChanged(device::BluetoothAdapter* adapter,
+                             device::BluetoothDevice* device) OVERRIDE;
+  virtual void DeviceRemoved(device::BluetoothAdapter* adapter,
+                             device::BluetoothDevice* device) OVERRIDE;
+
+  // device::BluetoothDevice::PairingDelegate override.
+  virtual void RequestPinCode(device::BluetoothDevice* device) OVERRIDE;
+  virtual void RequestPasskey(device::BluetoothDevice* device) OVERRIDE;
+  virtual void DisplayPinCode(device::BluetoothDevice* device,
+                              const std::string& pincode) OVERRIDE;
+  virtual void DisplayPasskey(device::BluetoothDevice* device,
+                              uint32 passkey) OVERRIDE;
+  virtual void KeysEntered(device::BluetoothDevice* device,
+                           uint32 entered) OVERRIDE;
+  virtual void ConfirmPasskey(device::BluetoothDevice* device,
+                              uint32 passkey) OVERRIDE;
+  virtual void AuthorizePairing(device::BluetoothDevice* device) OVERRIDE;
+
+ private:
+  // Internal method called by BluetoothAdapterFactory to provide the adapter
+  // object.
+  void OnGetAdapter(scoped_refptr<device::BluetoothAdapter> adapter);
+
+  // Presents a notification to the user that a device |device| is making a
+  // pairing request. The exact message to display is given in |message| and
+  // should include all relevant instructions, if |with_buttons| is true then
+  // the notification will have Accept and Reject buttons, if false only the
+  // usual cancel/dismiss button will be present on the notification.
+  void NotifyPairing(device::BluetoothDevice* device,
+                     const base::string16& message,
+                     bool with_buttons);
+
+  // Clears any shown pairing notification now that the device has been paired.
+  void NotifyPairedDevice(device::BluetoothDevice* device);
+
+  // Reference to the underlying BluetoothAdapter object, holding this reference
+  // ensures we stay around as the pairing delegate for that adapter.
+  scoped_refptr<device::BluetoothAdapter> adapter_;
+
+  // Set of currently paired devices, stored by Bluetooth address, used to
+  // filter out property changes for devices that were previously paired.
+  std::set<std::string> paired_devices_;
+
+  // Note: This should remain the last member so it'll be destroyed and

[sky, 2014/03/03 22:56:22]

nit: IMO comments like this are easy to miss. Better to be explicit by having
code in the destructor.

[keybuk, 2014/03/03 23:40:39]

The problem this comment is referring to isn't a runtime error, as you say
that'd be easy to fix by just explicitly cleaning up members in the Destructor.

The problem is a compile-time error, the compiler ultimately doesn't trust us to
get destruction right when it comes to class members with their own destructors,
so throws an error if this isn't the last thing.

Thus this comment exists (and exists in many places WeakPtrFactory is used in
Chrome) because it's a particularly obscure compiler error, and to explain what
it means when someone decides to ignore the line and move it anyway ;-)

+  // invalidate its weak pointers before any other members are destroyed.
+  base::WeakPtrFactory<BluetoothNotificationController> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(BluetoothNotificationController);
+};
+
+}  // namespace internal
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_CHROMEOS_BLUETOOTH_BLUETOOTH_NOTIFICATION_CONTROLLER_H_