Method safe_timeval_replacement_for_nonzero_datetime

sql/sql_class.cc:1336–1348

@brief Convert a non-zero DATETIME to its safe timeval based representation, which guarantees a safe roundtrip DATETIME->timeval->DATETIME, e.g. to optimize: WHERE timestamp_arg0 = datetime_arg1 in the way that we replace "datetime_arg1" to its TIMESTAMP equivalent "timestamp_arg1" and switch from DATETIME comparison to TIMESTAMP comparison: WHERE timestamp_arg0 = timestamp_

              does not have a safe replacement.
*/
Timeval_null
THD::safe_timeval_replacement_for_nonzero_datetime(const Datetime &dt)
{
  used|= THD::TIME_ZONE_USED;
  DBUG_ASSERT(non_zero_date(dt.get_mysql_time()));
  uint error= 0;
  const MYSQL_TIME *ltime= dt.get_mysql_time();
  my_time_t sec= variables.time_zone->TIME_to_gmt_sec(ltime, &error);
  if (error /* (1) */ ||
      !variables.time_zone->is_monotone_continuous_around(sec) /* (2) */)
    return Timeval_null();
  return Timeval_null(sec, ltime->second_part);
}


#ifdef _WIN32