metrics_stopwatch.h

// Copyright (c) 2011 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 PLUGIN_METRICS_STOPWATCH_H_
#define PLUGIN_METRICS_STOPWATCH_H_

#include <string>
#include <base/basictypes.h>
#include <base/memory/scoped_ptr.h>
#include <metrics/metrics_library.h>

class MetricsStopwatch {
 public:
  MetricsStopwatch(const char* name, int min, int max, int nbuckets);

  void Start();
  void Stop();  // and send measurement to UMA and reset
  void StopIfStarted(); // and send measurement to UMA and reset

  // In some situations, we can receive a report of the start time
  // after the stop time.  These report when both start and stop are
  // known.
  void SetStart(unsigned long long start);
  void SetStop(unsigned long long stop);

  void Reset();  // Only call this to abandon a measurement; Stop*()
                 // and Set*() already call this automatically.

  static unsigned long long GetTimeMs(void);

  void SetMetrics(MetricsLibraryInterface *m);
 protected:
  void ReportAndReset();

  scoped_ptr<MetricsLibraryInterface> metrics_;
  std::string name_;
  int min_;
  int max_;
  int nbuckets_;
  unsigned long long start_;
  unsigned long long stop_;

 private:
  DISALLOW_COPY_AND_ASSIGN(MetricsStopwatch);
};

#endif  // PLUGIN_METRICS_STOPWATCH_H_