internal/ceres/event_logger.h

// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2024 Google Inc. All rights reserved.
// http://ceres-solver.org/
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// Author: strandmark@google.com (Petter Strandmark)

#ifndef CERES_INTERNAL_EVENT_LOGGER_H_
#define CERES_INTERNAL_EVENT_LOGGER_H_

#include <string>

#include "absl/time/time.h"
#include "ceres/internal/disable_warnings.h"
#include "ceres/internal/export.h"

namespace ceres::internal {

// Log a series of events, recording for each event the time elapsed
// since the last event and since the creation of the object.
//
// The information is output to VLOG(3) upon destruction. A
// name::Total event is added as the final event right before
// destruction.
//
// Example usage:
//
//  void Foo() {
//    EventLogger event_logger("Foo");
//    Bar1();
//    event_logger.AddEvent("Bar1")
//    Bar2();
//    event_logger.AddEvent("Bar2")
//    Bar3();
//  }
//
// Will produce output that looks like
//
//  Foo
//      Bar1:  time1  time1
//      Bar2:  time2  time1 + time2;
//     Total:  time3  time1 + time2 + time3;
class CERES_NO_EXPORT EventLogger {
 public:
  explicit EventLogger(const std::string& logger_name);
  ~EventLogger();
  void AddEvent(const std::string& event_name);

 private:
  const absl::Time start_time_;
  absl::Time last_event_time_;
  std::string events_;
};

}  // namespace ceres::internal

#include "ceres/internal/reenable_warnings.h"

#endif  // CERES_INTERNAL_EVENT_LOGGER_H_