third_party/WebKit/Source/modules/sensor/SensorPollingStrategy.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 SensorPollingStrategy_h
#define SensorPollingStrategy_h

#include "device/generic_sensor/public/interfaces/sensor_provider.mojom-blink.h"
#include "platform/Timer.h"
#include "platform/heap/Handle.h"
#include "wtf/Functional.h"

namespace blink {

// This class provides different polling behaviour depending on
// the given 'ReportingMode':
// - for 'CONTINUOUS' mode the polling function is invoked periodically
//   with the given polling period (on timer event).
// - for 'ONCHANGE' mode the polling function is invoked only after client
//   calls 'onSensorReadingChanged()' however considering the given polling
//   period: guaranteed not to be called more often than expected.
class SensorPollingStrategy {
 public:
  static std::unique_ptr<SensorPollingStrategy> create(
      double pollingPeriod,
      std::unique_ptr<Function<void()>> pollFunc,
      device::mojom::blink::ReportingMode);

  virtual void onSensorReadingChanged() {}
  virtual void startPolling() = 0;
  virtual void stopPolling() = 0;

  virtual ~SensorPollingStrategy();

 protected:
  SensorPollingStrategy(double pollingPeriod,
                        std::unique_ptr<Function<void()>>);
  virtual void pollForData(TimerBase*) = 0;

  double m_pollingPeriod;
  std::unique_ptr<Function<void()>> m_pollFunc;
  Timer<SensorPollingStrategy> m_timer;
};

}  // namespace blink

#endif  // SensorPollingStrategy_h