Chrome OS uWeave Characteristics Server

components/proximity_auth/ble/bluetooth_low_energy_advertisement_rotator.h

+// 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 COMPONENTS_PROXIMITY_AUTH_BLE_BLUETOOTH_LOW_ENERGY_WEAVE_ADVERTISEMENT_ROTATOR_H_
+#define COMPONENTS_PROXIMITY_AUTH_BLE_BLUETOOTH_LOW_ENERGY_WEAVE_ADVERTISEMENT_ROTATOR_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <map>
+#include <memory>
+#include <vector>
+
+#include "components/proximity_auth/ble/bluetooth_low_energy_eid_generator.h"
+#include "device/bluetooth/bluetooth_advertisement.h"
+
+namespace proximity_auth {
+namespace weave {
+namespace {
+
+using Advertisement = device::BluetoothAdvertisement::Data;
+
+}  // namespace
+
+// Represent a queue of advertisements for the devices added.
+// Devices are identified by their bluetooth address and no device with the same
+// address will be added.
+// The class also provides simple conversion from bluetooth address to it's
+// corresponding advertisement. The advertisement returned will be the most up
+// to date at that moment with the EID seed and EID of that period.
+class BluetoothLowEnergyAdvertisementRotator {
+ public:
+  class Factory {
+   public:
+    static std::unique_ptr<BluetoothLowEnergyAdvertisementRotator> NewInstance(
+        std::string service_uuid);
+
+    // Exposed for testing.
+    static void SetInstanceForTesting(Factory* factory);
+
+   protected:
+    // Exposed for testing.
+    virtual std::unique_ptr<BluetoothLowEnergyAdvertisementRotator>
+    BuildInstance(std::string service_uuid);
+
+   private:
+    static Factory* factory_instance_;
+  };
+
+  ~BluetoothLowEnergyAdvertisementRotator();
+
+  bool IsRotatorEmpty();
+
+  // Get the next device in the rotator and it's corresponding advertisement.
+  // The rotator must not be empty.
+  std::pair<std::string, std::unique_ptr<Advertisement>> GetNextAdvertisement();
+
+  // Move to the next advertisement.
+  void RotateAdvertisement();
+
+  // Adds a device to the rotator.
+  // Device must not exist already in the rotator.
+  void AddDevice(const RemoteDevice& device);
+
+  // Remove the device from the rotator.
+  // Device must exist in the rotator.
+  void RemoveDevice(const RemoteDevice& device);
+
+  // Inject the device to the front of the queue.
+  void CutAdvertisementLine(std::string bluetooth_address);
+
+  bool HasDeviceWithAddress(std::string bluetooth_address);
+
+ protected:
+  BluetoothLowEnergyAdvertisementRotator(std::string service_uuid);
+
+ private:
+  // Get the index of the device with |bluetooth_address| in devices_.
+  // Device must exist in the rotator.
+  int GetPosWithAddress(std::string bluetooth_address);
+
+  const std::string service_uuid_;
+
+  std::unique_ptr<BluetoothLowEnergyEidGenerator> eid_generator_;
+
+  // A queue containing index into |devices_|. GetNextAdvertisement and
+  // Rotateadvertisement will be based on this queue.
+  std::vector<int> waiting_queue_;
+
+  // Devices added to the rotator.
+  std::vector<RemoteDevice> devices_;
+};
+
+}  // namespace weave
+
+}  // namespace proximity_auth
+
+#endif  // COMPONENTS_PROXIMITY_AUTH_BLE_BLUETOOTH_LOW_ENERGY_WEAVE_ADVERTISEMENT_ROTATOR_H_