metrics_reporter.h

// Copyright 2015 The Chromium OS 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 THERMALD_METRICS_REPORTER_H_
#define THERMALD_METRICS_REPORTER_H_

#include <map>
#include <memory>
#include <string>
#include <vector>

#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "metrics/metrics_library.h"

#include "thermald/key_value_publisher.h"
#include "thermald/temperature_monitor_interface.h"

namespace thermald {

// Class to report the thermal state of the device to UMA.
class MetricsReporter {
 public:
  // Constructs a metrics reporter which reports the thermal state of the
  // device at the specified period. The metrics reporter subscribes to the
  // given publisher object to be notified on changes in the thermal output
  // values. Currently only changes in the state of a thermal zone are
  // processed. MetricsReporter does not take ownership of the output publisher
  // and the metrics library, so they must out-live the metrics reporter.
  MetricsReporter(const std::string &uma_metric_prefix,
                  KeyValuePublisher *output_publisher,
                  MetricsLibraryInterface *metrics_lib,
                  base::TimeDelta reporting_period);

  // Adds a temperature to be included in the reports of the thermal state.
  // The metrics reporter subscribes to the given temperature monitor to be
  // notified on temperature changes.
  void AddTemperature(const std::string &name,
                      TemperatureMonitorInterface *temperature_monitor);

  // Starts the periodic reporting of the thermal state.
  void Start();

  // Stops the periodic reporting of the thermal state.
  void Stop();

 private:
  friend class MetricsReporterTest;

  // Structure with the current value of a monitored temperature and the name
  // of the UMA histogram for this temperature.
  struct TemperatureMetricsData {
    int current_value;
    std::string histogram;
  };

  // Structure with the current state of a thermal zone and the name of the
  // UMA histogram for this zone.
  struct ThermalStateMetricsData {
    int current_state;
    std::string histogram;
  };

  void ReportMetrics();
  void OnOutputChanged(const std::string &key, int value);
  void OnTemperatureChanged(const std::string &name, int value);

  // Histogram prefix used to consolidate the UMA metrics for new products in
  // the backend. If histogram prefix is not configured, then default prefix
  // will be "Platform".
  const std::string histogram_prefix_;
  // Map with the current values of the monitored temperatures and the names
  // of the corresponding histograms.
  std::map<std::string, TemperatureMetricsData> temperature_metrics_data_;
  // Map with the current state of the thermal zones and the name of the
  // corresponding histograms.
  std::map<std::string, ThermalStateMetricsData> thermal_state_metrics_data_;
  MetricsLibraryInterface *metrics_lib_;
  const base::TimeDelta reporting_period_;
  std::unique_ptr<base::RepeatingTimer> timer_;
#if BASE_VER < 860220
  std::unique_ptr<KeyValuePublisher::Subscription> subscription_outputs_;
  std::vector<std::unique_ptr<TemperatureMonitorInterface::Subscription>>
      temperature_monitor_subscriptions_;
#else
  base::CallbackListSubscription subscription_outputs_;
  std::vector<base::CallbackListSubscription>
      temperature_monitor_subscriptions_;
#endif
  base::WeakPtrFactory<MetricsReporter> weak_ptr_factory_;

  DISALLOW_COPY_AND_ASSIGN(MetricsReporter);
};

}  // namespace thermald

#endif  // THERMALD_METRICS_REPORTER_H_