Update AvgCounter to have the ability to include last period metric for subsequent intervals withou…

webrtc/video/stats_counter.h

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 60 matching lines @@
 // AggregatedStats stats = counter.GetStats();
 // stats: {min:4, max:15, avg:8}
 //
 
 // Note: StatsCounter takes ownership of |observer|.
 
 class StatsCounter {
  public:
   virtual ~StatsCounter();
 
+  // Gets metric within an interval. Returns true on success false otherwise.
   virtual bool GetMetric(int* metric) const = 0;
 
+  // Gets the value to use for an interval without samples.
+  virtual int GetValueForEmptyInterval() const = 0;
+
+  // Gets aggregated stats (i.e. aggregate of periodically computed metrics).
   AggregatedStats GetStats();
 
+  // Reports metrics for elapsed intervals to AggregatedCounter and GetStats.
+  AggregatedStats ProcessAndGetStats();
+
+  // Reports metrics for elapsed intervals to AggregatedCounter and pauses stats
+  // (i.e. empty intervals will be discarded until next sample is added).
+  void ProcessAndPause();
+
  protected:
   StatsCounter(Clock* clock,
                bool include_empty_intervals,
                StatsCounterObserver* observer);
 
   void Add(int sample);
   void Set(int sample);
 
   int max_;
   int64_t sum_;
   int64_t num_samples_;
   int64_t last_sum_;
 
+  const std::unique_ptr<AggregatedCounter> aggregated_counter_;
+
  private:
-  bool TimeToProcess();
+  bool TimeToProcess(int* num_elapsed_intervals);
   void TryProcess();
+  void ReportMetricToAggregatedCounter(int value, int num_values_to_add) const;
+  bool IncludeEmptyIntervals() const;
 
   Clock* const clock_;
   const bool include_empty_intervals_;
   const std::unique_ptr<StatsCounterObserver> observer_;
-  const std::unique_ptr<AggregatedCounter> aggregated_counter_;
   int64_t last_process_time_ms_;
+  bool paused_;
 };
 
 // AvgCounter: average of samples
 //
 //           | *      *      *      | *           *       | ...
 //           | Add(5) Add(1) Add(6) | Add(5)      Add(5)  |
 // GetMetric | (5 + 1 + 6) / 3      | (5 + 5) / 2         |
 //
+// |include_empty_intervals|: If set, intervals without samples will be included
+//                            in the stats. The value for an interval is
+//                            determined by GetValueForEmptyInterval().
+//
 class AvgCounter : public StatsCounter {
  public:
-  AvgCounter(Clock* clock, StatsCounterObserver* observer);
+  AvgCounter(Clock* clock,
+             StatsCounterObserver* observer,
+             bool include_empty_intervals);
   ~AvgCounter() override {}
 
   void Add(int sample);
 
  private:
   bool GetMetric(int* metric) const override;
 
+  // Returns the last computed metric (i.e. from GetMetric).
+  int GetValueForEmptyInterval() const override;
+
   RTC_DISALLOW_COPY_AND_ASSIGN(AvgCounter);
 };
 
 // MaxCounter: maximum of samples
 //
 //           | *      *      *      | *           *       | ...
 //           | Add(5) Add(1) Add(6) | Add(5)      Add(5)  |
 // GetMetric | max: (5, 1, 6)       | max: (5, 5)         |
 //
 class MaxCounter : public StatsCounter {
  public:
   MaxCounter(Clock* clock, StatsCounterObserver* observer);
   ~MaxCounter() override {}
 
   void Add(int sample);
 
  private:
   bool GetMetric(int* metric) const override;
+  int GetValueForEmptyInterval() const override;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(MaxCounter);
 };
 
 // PercentCounter: percentage of samples
 //
 //           | *      *      *      | *           *       | ...
 //           | Add(T) Add(F) Add(T) | Add(F)      Add(T)  |
 // GetMetric | 100 * 2 / 3          | 100 * 1 / 2         |
 //
 class PercentCounter : public StatsCounter {
  public:
   PercentCounter(Clock* clock, StatsCounterObserver* observer);
   ~PercentCounter() override {}
 
   void Add(bool sample);
 
  private:
   bool GetMetric(int* metric) const override;
+  int GetValueForEmptyInterval() const override;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(PercentCounter);
 };
 
 // PermilleCounter: permille of samples
 //
 //           | *      *      *      | *         *         | ...
 //           | Add(T) Add(F) Add(T) | Add(F)    Add(T)    |
 // GetMetric | 1000 *  2 / 3        | 1000 * 1 / 2        |
 //
 class PermilleCounter : public StatsCounter {
  public:
   PermilleCounter(Clock* clock, StatsCounterObserver* observer);
   ~PermilleCounter() override {}
 
   void Add(bool sample);
 
  private:
   bool GetMetric(int* metric) const override;
+  int GetValueForEmptyInterval() const override;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(PermilleCounter);
 };
 
 // RateCounter: units per second
 //
 //           | *      *      *      | *           *       | ...
 //           | Add(5) Add(1) Add(6) | Add(5)      Add(5)  |
 //           |<------ 2 sec ------->|                     |
 // GetMetric | (5 + 1 + 6) / 2      | (5 + 5) / 2         |
 //
+// |include_empty_intervals|: If set, intervals without samples will be included
+//                            in the stats. The value for an interval is
+//                            determined by GetValueForEmptyInterval().
+//
 class RateCounter : public StatsCounter {
  public:
   RateCounter(Clock* clock,
               StatsCounterObserver* observer,
               bool include_empty_intervals);
   ~RateCounter() override {}
 
   void Add(int sample);
 
  private:
   bool GetMetric(int* metric) const override;
+  int GetValueForEmptyInterval() const override;  // Returns zero.
 
   RTC_DISALLOW_COPY_AND_ASSIGN(RateCounter);
 };
 
 // RateAccCounter: units per second (used for counters)
 //
 //           | *      *      *      | *         *         | ...
 //           | Set(5) Set(6) Set(8) | Set(11)   Set(13)   |
 //           |<------ 2 sec ------->|                     |
 // GetMetric | 8 / 2                | (13 - 8) / 2        |
 //
+// |include_empty_intervals|: If set, intervals without samples will be included
+//                            in the stats. The value for an interval is
+//                            determined by GetValueForEmptyInterval().
+//
 class RateAccCounter : public StatsCounter {
  public:
   RateAccCounter(Clock* clock,
                  StatsCounterObserver* observer,
                  bool include_empty_intervals);
   ~RateAccCounter() override {}
 
   void Set(int sample);
 
  private:
   bool GetMetric(int* metric) const override;
+  int GetValueForEmptyInterval() const override;  // Returns zero.
 
   RTC_DISALLOW_COPY_AND_ASSIGN(RateAccCounter);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_VIDEO_STATS_COUNTER_H_