mysql 服务器端命令源码（五）--show create database

bool mysqld_show_create_db(THD *thd, char *dbname,

                           HA_CREATE_INFO *create_info)

{

  char buff[2048];

  String buffer(buff, sizeof(buff), system_charset_info);

#ifndef NO_EMBEDDED_ACCESS_CHECKS

  Security_context *sctx= thd->security_ctx;

  uint db_access;

#endif

  HA_CREATE_INFO create;

  uint create_options = create_info ? create_info->options : 0;

  Protocol *protocol=thd->protocol;

  DBUG_ENTER("mysql_show_create_db");

#ifndef NO_EMBEDDED_ACCESS_CHECKS

  if (test_all_bits(sctx->master_access, DB_ACLS))

    db_access=DB_ACLS;

  else

    db_access= (acl_get(sctx->host, sctx->ip, sctx->priv_user, dbname, 0) |

sctx->master_access);

  if (!(db_access & DB_ACLS) && check_grant_db(thd,dbname))

  {

    my_error(ER_DBACCESS_DENIED_ERROR, MYF(0),

             sctx->priv_user, sctx->host_or_ip, dbname);

    general_log_print(thd,COM_INIT_DB,ER(ER_DBACCESS_DENIED_ERROR),

                      sctx->priv_user, sctx->host_or_ip, dbname);

    DBUG_RETURN(TRUE);

  }

#endif

  if (is_schema_db(dbname))

  {

    dbname= INFORMATION_SCHEMA_NAME.str;

    create.default_table_charset= system_charset_info;

  }

  else

  {

    if (check_db_dir_existence(dbname))

    {

      my_error(ER_BAD_DB_ERROR, MYF(0), dbname);

      DBUG_RETURN(TRUE);

    }

    load_db_opt_by_name(thd, dbname, &create);

  }

  List<Item> field_list;

  field_list.push_back(new Item_empty_string("Database",NAME_CHAR_LEN));

  field_list.push_back(new Item_empty_string("Create Database",1024));

  if (protocol->send_result_set_metadata(&field_list,

                            Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF))

    DBUG_RETURN(TRUE);

  protocol->prepare_for_resend();

  protocol->store(dbname, strlen(dbname), system_charset_info);

  buffer.length(0);

  buffer.append(STRING_WITH_LEN("CREATE DATABASE "));

  if (create_options & HA_LEX_CREATE_IF_NOT_EXISTS)

    buffer.append(STRING_WITH_LEN("/*!32312 IF NOT EXISTS*/ "));

  append_identifier(thd, &buffer, dbname, strlen(dbname));

  if (create.default_table_charset)

  {

    buffer.append(STRING_WITH_LEN(" /*!40100"));

    buffer.append(STRING_WITH_LEN(" DEFAULT CHARACTER SET "));

    buffer.append(create.default_table_charset->csname);

    if (!(create.default_table_charset->state & MY_CS_PRIMARY))

    {

      buffer.append(STRING_WITH_LEN(" COLLATE "));

      buffer.append(create.default_table_charset->name);

    }

    buffer.append(STRING_WITH_LEN(" */"));

  }

  protocol->store(buffer.ptr(), buffer.length(), buffer.charset());

  if (protocol->write())

    DBUG_RETURN(TRUE);

  my_eof(thd);

  DBUG_RETURN(FALSE);

}