Function copy_on_update_columns_list

sql/sql_trigger.cc:1646–1691

Deep copy of on update columns list created on parsing a trigger definition. The destination list and its elements are allocated on table's memory root. @param table_mem_root table mem_root from where a memory is allocated. @param [out] dst_col_names destination list where to copy an original one @param src_col_names source list that has to be copied @return false on success, true

  @return false on success, true on OOM error
*/
static bool
copy_on_update_columns_list(MEM_ROOT *table_mem_root,
                            List<LEX_CSTRING> **dst_col_names,
                            List<LEX_CSTRING> *src_col_names)
{
  if (!src_col_names)
  {
    *dst_col_names= nullptr;
    return false;
  }

  /*
    In case the clause <OF column_list> is present in definition of a trigger,
    the list lex.trg_chistics.on_update_col_names mustn't be empty.
    For the case where this clause is missed, the pointer
      lex.trg_chistics.on_update_col_names
    itself has nullptr value. So, do assert check here that the list is not
    empty.
  */
  DBUG_ASSERT(!src_col_names->is_empty());

  List<LEX_CSTRING> *result= new (table_mem_root) List<LEX_CSTRING>();
  if (!result)
    return true; // OOM

  List_iterator_fast<LEX_CSTRING> columns_it(*src_col_names);
  LEX_CSTRING *column_name;

  while ((column_name= columns_it++))
  {
    LEX_CSTRING *cname= (LEX_CSTRING*)alloc_root(table_mem_root,
                                                 sizeof(LEX_CSTRING));

    if (!cname)
      return true; // OOM

    *cname= safe_lexcstrdup_root(table_mem_root, *column_name);

    if (!cname->str ||
        result->push_back(cname, table_mem_root))
      return true; // OOM
  }

  *dst_col_names= result;
  return false;
}


/**