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#ifndef MOZC_BASE_STOPWATCH_H_
#define MOZC_BASE_STOPWATCH_H_

#include "absl/time/time.h"

namespace mozc {

class Stopwatch {
 public:
  enum StopwatchState {
    STOPWATCH_RUNNING,
    STOPWATCH_STOPPED,
  };

  // Initializes a new stopwatch object, starts measuring elapsed time,
  // and returns the stopwatch object.
  static Stopwatch StartNew();

  // Sets elapsed time to zero.
  // Stops the time counting.
  void Reset();

  // (Re)starts the time counting.
  // This function does not reset elapsed time so that you can use Start()
  // to accumulate a periodic activity.
  void Start();

  // Stops the time counting.
  // This function does not reset elapsed time so that you can use Start()
  // to accumulate a periodic activity.
  void Stop();

  // Returns the elapsed time.
  absl::Duration GetElapsed() const;

  // Returns true if the time counting is on-going.
  bool IsRunning() const;

 private:
  StopwatchState state_ = STOPWATCH_STOPPED;
  absl::Time start_ = absl::InfinitePast();
  absl::Duration elapsed_;
};

}  // namespace mozc

#endif  // MOZC_BASE_STOPWATCH_H_
