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// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef REMOTING_BASE_RATE_COUNTER_H_
#define REMOTING_BASE_RATE_COUNTER_H_
#include <stdint.h>
#include <utility>
#include "base/containers/queue.h"
#include "base/gtest_prod_util.h"
#include "base/memory/raw_ptr.h"
#include "base/sequence_checker.h"
#include "base/time/default_tick_clock.h"
#include "base/time/tick_clock.h"
#include "base/time/time.h"
namespace remoting {
// Measures average rate per second of a sequence of point rate samples
// over a specified time window. This can be used to measure bandwidth, frame
// rates, etc.
class RateCounter {
public:
// Constructs a rate counter over the specified |time_window|.
explicit RateCounter(base::TimeDelta time_window);
// Construct a RateCounter for tests with an alternate tick clock.
RateCounter(base::TimeDelta time_window, const base::TickClock* tick_clock);
RateCounter(const RateCounter&) = delete;
RateCounter& operator=(const RateCounter&) = delete;
virtual ~RateCounter();
// Records a point event count to include in the rate.
void Record(int64_t value);
// Returns the rate-per-second of values recorded over the time window.
// Note that rates reported before |time_window| has elapsed are not accurate.
double Rate() const;
private:
// Type used to store data points with timestamps.
typedef std::pair<base::TimeTicks, int64_t> DataPoint;
// Removes data points more than |time_window| older than |current_time|.
void EvictOldDataPoints(base::TimeTicks current_time);
// Time window over which to calculate the rate.
const base::TimeDelta time_window_;
// Queue containing data points in the order in which they were recorded.
base::queue<DataPoint> data_points_;
// Sum of values in |data_points_|.
int64_t sum_ = 0;
const raw_ptr<const base::TickClock> tick_clock_ =
base::DefaultTickClock::GetInstance();
SEQUENCE_CHECKER(sequence_checker_);
};
} // namespace remoting
#endif // REMOTING_BASE_RATE_COUNTER_H_
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