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// 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_PROXIMITY_MONITOR_IMPL_H
#define COMPONENTS_PROXIMITY_AUTH_PROXIMITY_MONITOR_IMPL_H
#include <memory>
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "components/cryptauth/remote_device.h"
#include "components/proximity_auth/proximity_monitor.h"
#include "device/bluetooth/bluetooth_device.h"
namespace base {
class TickClock;
class TimeTicks;
}
namespace device {
class BluetoothAdapter;
}
namespace proximity_auth {
class ProximityMonitorObserver;
// The concrete implemenation of the proximity monitor interface.
class ProximityMonitorImpl : public ProximityMonitor {
public:
// The |observer| is not owned, and must outlive |this| instance.
ProximityMonitorImpl(const cryptauth::RemoteDevice& remote_device,
std::unique_ptr<base::TickClock> clock);
~ProximityMonitorImpl() override;
// ProximityMonitor:
void Start() override;
void Stop() override;
Strategy GetStrategy() const override;
bool IsUnlockAllowed() const override;
bool IsInRssiRange() const override;
void RecordProximityMetricsOnAuthSuccess() override;
void AddObserver(ProximityMonitorObserver* observer) override;
void RemoveObserver(ProximityMonitorObserver* observer) override;
protected:
// Sets the proximity detection strategy. Exposed for testing.
// TODO(isherman): Stop exposing this for testing once prefs are properly
// hooked up.
virtual void SetStrategy(Strategy strategy);
private:
struct TransmitPowerReading {
TransmitPowerReading(int transmit_power, int max_transmit_power);
// Returns true if |this| transmit power reading indicates proximity.
bool IsInProximity() const;
// The current transmit power.
int transmit_power;
// The maximum possible transmit power.
int max_transmit_power;
};
// Callback for asynchronous initialization of the Bluetooth adpater.
void OnAdapterInitialized(scoped_refptr<device::BluetoothAdapter> adapter);
// Ensures that the app is periodically polling for the proximity status
// between the remote and the local device iff it should be, based on the
// current app state.
void UpdatePollingState();
// Performs a scheduled |UpdatePollingState()| operation. This method is
// used to distinguish periodically scheduled calls to |UpdatePollingState()|
// from event-driven calls, which should be handled differently.
void PerformScheduledUpdatePollingState();
// Returns |true| iff the app should be periodically polling for the proximity
// status between the remote and the local device.
bool ShouldPoll() const;
// Polls the connection information.
void Poll();
// Callback to received the polled-for connection info.
void OnConnectionInfo(
const device::BluetoothDevice::ConnectionInfo& connection_info);
// Resets the proximity state to |false|, and clears all member variables
// tracking the proximity state.
void ClearProximityState();
// Updates the proximity state with a new |connection_info| sample of the
// current RSSI and Tx power, and the device's maximum Tx power.
void AddSample(
const device::BluetoothDevice::ConnectionInfo& connection_info);
// Checks whether the proximity state has changed based on the current
// samples. Notifies |observers_| on a change.
void CheckForProximityStateChange();
// The remote device being monitored.
const cryptauth::RemoteDevice remote_device_;
// The observers attached to the ProximityMonitor.
base::ObserverList<ProximityMonitorObserver> observers_;
// The Bluetooth adapter that will be polled for connection info.
scoped_refptr<device::BluetoothAdapter> bluetooth_adapter_;
// The strategy used to determine whether the remote device is in proximity.
Strategy strategy_;
// Whether the remote device is currently in close proximity to the local
// device.
bool remote_device_is_in_proximity_;
// Whether the proximity monitor is active, i.e. should possibly be scanning
// for proximity to the remote device.
bool is_active_;
// The exponentailly weighted rolling average of the RSSI, used to smooth the
// RSSI readings. Null if the monitor is inactive, has not recently observed
// an RSSI reading, or the most recent connection info included an invalid
// measurement.
std::unique_ptr<double> rssi_rolling_average_;
// The last TX power reading. Null if the monitor is inactive, has not
// recently observed a TX power reading, or the most recent connection info
// included an invalid measurement.
std::unique_ptr<TransmitPowerReading> last_transmit_power_reading_;
// The timestamp of the last zero RSSI reading. An RSSI value of 0 is special
// because both devices adjust their transmit powers such that the RSSI is in
// this golden range, if possible. Null if the monitor is inactive, has not
// recently observed an RSSI reading, or the most recent connection info
// included an invalid measurement.
std::unique_ptr<base::TimeTicks> last_zero_rssi_timestamp_;
// Used to access non-decreasing time measurements.
std::unique_ptr<base::TickClock> clock_;
// Used to vend weak pointers for polling. Using a separate factory for these
// weak pointers allows the weak pointers to be invalidated when polling
// stops, which effectively cancels the scheduled tasks.
base::WeakPtrFactory<ProximityMonitorImpl> polling_weak_ptr_factory_;
// Used to vend all other weak pointers.
base::WeakPtrFactory<ProximityMonitorImpl> weak_ptr_factory_;
DISALLOW_COPY_AND_ASSIGN(ProximityMonitorImpl);
};
} // namespace proximity_auth
#endif // COMPONENTS_PROXIMITY_AUTH_PROXIMITY_MONITOR_IMPL_H
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