Function show_engine_binlog_events

sql/sql_repl.cc:4932–5026

Version of mysql_show_binlog_events() for --binlog-storage-engine. */

/* Version of mysql_show_binlog_events() for --binlog-storage-engine. */
static bool
show_engine_binlog_events(THD* thd, Protocol *protocol, LEX_MASTER_INFO *lex_mi)
{
  bool err= false;

  DBUG_ASSERT(opt_binlog_engine_hton);
  DBUG_ASSERT(thd->lex->sql_command == SQLCOM_SHOW_BINLOG_EVENTS);
  handler_binlog_reader *reader=
    (*opt_binlog_engine_hton->get_binlog_reader)(false);
  if (!reader)
  {
    my_error(ER_OUT_OF_RESOURCES, MYF(0));
    return true;
  }

  ulonglong pos= lex_mi->pos;
  /*
    The positions "0" and "4" are unfortunately traditionally used
    interchangeably to mean "the start of the binlog". Thus, we might here
    easily see a starting position of "4", which is probably not valid in
    the engine, but which really means "start of the file".

    So here we have this ugly hack where "4" means the same as "0". Well,
    use of offsets is discourated anyway in the new binlog (in favour of
    GTID), and "4" is not going to be a valid position most likely, or if
    it is, "0" will be equivalent (at least it is so for the InnoDB binlog
    implementation.
  */
  if (pos == 4)
    pos= 0;
  if (reader->init_legacy_pos(thd, lex_mi->log_file_name, pos))
  {
    err= true;
    goto end;
  }
  /* The engine reader will stop at the end of the requested file. */
  reader->enable_single_file();

  {
    SELECT_LEX_UNIT *unit= &thd->lex->unit;
    unit->set_limit(thd->lex->current_select);
    uint64_t file_no= reader->cur_file_no;
    ha_rows limit= unit->lim.get_select_limit();
    String packet;
    Format_description_log_event fd(4);
    char name_buf[FN_REFLEN];
    opt_binlog_engine_hton->get_filename(name_buf, file_no);

    for (ha_rows event_count= 0; event_count < limit; ++event_count)
    {
      packet.length(0);
      int reader_error= reader->read_log_event(&packet, 0,
            thd->variables.max_allowed_packet + MAX_LOG_EVENT_HEADER);
      if (reader_error)
      {
        if (reader_error != LOG_READ_EOF)
        {
          my_error(ER_ERROR_WHEN_EXECUTING_COMMAND, MYF(0),