absl::Status DiffTimes()

in sql_utils/public/functions/date_time_util.cc [3747:3792]
45 lines of code
19 McCabe index (conditional complexity)

absl::Status DiffTimes(const TimeValue& time1, const TimeValue& time2,
                       DateTimestampPart part, int64_t* output) {
  if (!time1.IsValid()) {
    return MakeEvalError() << "Invalid time value: " << time1.DebugString();
  }
  if (!time2.IsValid()) {
    return MakeEvalError() << "Invalid time value: " << time2.DebugString();
  }

  const absl::CivilSecond civil_time_1(1970, 1, 1, time1.Hour(), time1.Minute(),
                                       time1.Second());
  const absl::CivilSecond civil_time_2(1970, 1, 1, time2.Hour(), time2.Minute(),
                                       time2.Second());
  switch (part) {
    case HOUR:
    case MINUTE:
    case SECOND:
    case MILLISECOND:
    case MICROSECOND:
    case NANOSECOND:
      return DiffWithPartsSmallerThanDay(
          civil_time_1, time1.Nanoseconds(), civil_time_2, time2.Nanoseconds(),
          part,
          []() -> absl::Status {
            SQL_RET_CHECK_FAIL() << "TIME_DIFF should never have overflow error";
          } /* nano_overflow_error_maker */,
          output);
    case YEAR:
    case MONTH:
    case DAY:
    case DAYOFWEEK:
    case DAYOFYEAR:
    case QUARTER:
    case DATE:
    case WEEK:
    case DATETIME:
    case TIME:
      return MakeEvalError()
             << "Unsupported DateTimestampPart " << DateTimestampPart_Name(part)
             << " for TIME_DIFF";
    default:
      return MakeEvalError()
             << "Unexpected DateTimestampPart " << DateTimestampPart_Name(part)
             << " for TIME_DIFF";
  }
}