/* Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; version 2 of the License.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */

/**
 @file Representation of an SQL command.
*/

#ifndef SQL_CMD_INCLUDED
#define SQL_CMD_INCLUDED

/*
 When a command is added here, be sure it's also added in mysqld.cc
 in "struct show_var_st status_vars[]= {" ...

 If the command returns a result set or is not allowed in stored
 functions or triggers, please also make sure that
 sp_get_flags_for_command (sp_head.cc) returns proper flags for the
 added SQLCOM_.
*/

enum enum_sql_command {
 SQLCOM_SELECT, SQLCOM_CREATE_TABLE, SQLCOM_CREATE_INDEX, SQLCOM_ALTER_TABLE,
 SQLCOM_UPDATE, SQLCOM_INSERT, SQLCOM_INSERT_SELECT,
 SQLCOM_DELETE, SQLCOM_TRUNCATE, SQLCOM_DROP_TABLE, SQLCOM_DROP_INDEX,

 SQLCOM_SHOW_DATABASES, SQLCOM_SHOW_TABLES, SQLCOM_SHOW_FIELDS,
 SQLCOM_SHOW_KEYS, SQLCOM_SHOW_VARIABLES, SQLCOM_SHOW_STATUS,
 SQLCOM_SHOW_ENGINE_LOGS, SQLCOM_SHOW_ENGINE_STATUS, SQLCOM_SHOW_ENGINE_MUTEX,
 SQLCOM_SHOW_PROCESSLIST, SQLCOM_SHOW_MASTER_STAT, SQLCOM_SHOW_SLAVE_STAT,
 SQLCOM_SHOW_GRANTS, SQLCOM_SHOW_CREATE, SQLCOM_SHOW_CHARSETS,
 SQLCOM_SHOW_COLLATIONS, SQLCOM_SHOW_CREATE_DB, SQLCOM_SHOW_TABLE_STATUS,
 SQLCOM_SHOW_TRIGGERS,

 SQLCOM_LOAD,SQLCOM_SET_OPTION,SQLCOM_LOCK_TABLES,SQLCOM_UNLOCK_TABLES,
 SQLCOM_LOCK_TABLES_FOR_BACKUP, SQLCOM_LOCK_BINLOG_FOR_BACKUP,
 SQLCOM_UNLOCK_BINLOG,
 SQLCOM_GRANT,
 SQLCOM_CHANGE_DB, SQLCOM_CREATE_DB, SQLCOM_DROP_DB, SQLCOM_ALTER_DB,
 SQLCOM_REPAIR, SQLCOM_REPLACE, SQLCOM_REPLACE_SELECT,
 SQLCOM_CREATE_FUNCTION, SQLCOM_DROP_FUNCTION,
 SQLCOM_REVOKE,SQLCOM_OPTIMIZE, SQLCOM_CHECK,
 SQLCOM_ASSIGN_TO_KEYCACHE, SQLCOM_PRELOAD_KEYS,
 SQLCOM_FLUSH, SQLCOM_KILL, SQLCOM_ANALYZE,
 SQLCOM_ROLLBACK, SQLCOM_ROLLBACK_TO_SAVEPOINT,
 SQLCOM_COMMIT, SQLCOM_SAVEPOINT, SQLCOM_RELEASE_SAVEPOINT,
 SQLCOM_SLAVE_START, SQLCOM_SLAVE_STOP,
 SQLCOM_BEGIN, SQLCOM_CHANGE_MASTER,
 SQLCOM_RENAME_TABLE, 
 SQLCOM_RESET, SQLCOM_PURGE, SQLCOM_PURGE_BEFORE, SQLCOM_SHOW_BINLOGS,
 SQLCOM_SHOW_OPEN_TABLES,
 SQLCOM_HA_OPEN, SQLCOM_HA_CLOSE, SQLCOM_HA_READ,
 SQLCOM_SHOW_SLAVE_HOSTS, SQLCOM_DELETE_MULTI, SQLCOM_UPDATE_MULTI,
 SQLCOM_SHOW_BINLOG_EVENTS, SQLCOM_DO,
 SQLCOM_SHOW_WARNS, SQLCOM_EMPTY_QUERY, SQLCOM_SHOW_ERRORS,
 SQLCOM_SHOW_STORAGE_ENGINES, SQLCOM_SHOW_PRIVILEGES,
 SQLCOM_HELP, SQLCOM_CREATE_USER, SQLCOM_DROP_USER, SQLCOM_RENAME_USER,
 SQLCOM_REVOKE_ALL, SQLCOM_CHECKSUM,
 SQLCOM_CREATE_PROCEDURE, SQLCOM_CREATE_SPFUNCTION, SQLCOM_CALL,
 SQLCOM_DROP_PROCEDURE, SQLCOM_ALTER_PROCEDURE,SQLCOM_ALTER_FUNCTION,
 SQLCOM_SHOW_CREATE_PROC, SQLCOM_SHOW_CREATE_FUNC,
 SQLCOM_SHOW_STATUS_PROC, SQLCOM_SHOW_STATUS_FUNC,
 SQLCOM_PREPARE, SQLCOM_EXECUTE, SQLCOM_DEALLOCATE_PREPARE,
 SQLCOM_CREATE_VIEW, SQLCOM_DROP_VIEW,
 SQLCOM_CREATE_TRIGGER, SQLCOM_DROP_TRIGGER,
 SQLCOM_XA_START, SQLCOM_XA_END, SQLCOM_XA_PREPARE,
 SQLCOM_XA_COMMIT, SQLCOM_XA_ROLLBACK, SQLCOM_XA_RECOVER,
 SQLCOM_SHOW_PROC_CODE, SQLCOM_SHOW_FUNC_CODE,
 SQLCOM_ALTER_TABLESPACE,
 SQLCOM_INSTALL_PLUGIN, SQLCOM_UNINSTALL_PLUGIN,
 SQLCOM_BINLOG_BASE64_EVENT,
 SQLCOM_SHOW_PLUGINS,
 SQLCOM_CREATE_SERVER, SQLCOM_DROP_SERVER, SQLCOM_ALTER_SERVER,
 SQLCOM_CREATE_EVENT, SQLCOM_ALTER_EVENT, SQLCOM_DROP_EVENT,
 SQLCOM_SHOW_CREATE_EVENT, SQLCOM_SHOW_EVENTS,
 SQLCOM_SHOW_CREATE_TRIGGER,
 SQLCOM_ALTER_DB_UPGRADE,
 SQLCOM_SHOW_PROFILE, SQLCOM_SHOW_PROFILES,
 SQLCOM_SIGNAL, SQLCOM_RESIGNAL,
 SQLCOM_SHOW_RELAYLOG_EVENTS,
 SQLCOM_GET_DIAGNOSTICS,
 SQLCOM_ALTER_USER,

 /* SHOW SLAVE STATUS NOLOCK */
 SQLCOM_SHOW_SLAVE_NOLOCK_STAT,
 // TODO(mcallaghan): update status_vars in mysqld to export these
 SQLCOM_SHOW_USER_STATS, SQLCOM_SHOW_TABLE_STATS, SQLCOM_SHOW_INDEX_STATS,
 SQLCOM_SHOW_CLIENT_STATS, SQLCOM_SHOW_THREAD_STATS,

 SQLCOM_PURGE_ARCHIVE,
 SQLCOM_PURGE_ARCHIVE_BEFORE,
 /*
 When a command is added here, be sure it's also added in mysqld.cc
 in "struct show_var_st status_vars[]= {" ...
 */
 /* This should be the last !!! */
 SQLCOM_END
};

/**
 @class Sql_cmd - Representation of an SQL command.

 This class is an interface between the parser and the runtime.
 The parser builds the appropriate derived classes of Sql_cmd
 to represent a SQL statement in the parsed tree.
 The execute() method in the derived classes of Sql_cmd contain the runtime
 implementation.
 Note that this interface is used for SQL statements recently implemented,
 the code for older statements tend to load the LEX structure with more
 attributes instead.
 Implement new statements by sub-classing Sql_cmd, as this improves
 code modularity (see the 'big switch' in dispatch_command()), and decreases
 the total size of the LEX structure (therefore saving memory in stored
 programs).
 The recommended name of a derived class of Sql_cmd is Sql_cmd_<derived>.

 Notice that the Sql_cmd class should not be confused with the Statement class.
 Statement is a class that is used to manage an SQL command or a set 
 of SQL commands. When the SQL statement text is analyzed, the parser will
 create one or more Sql_cmd objects to represent the actual SQL commands.
*/
class Sql_cmd : public Sql_alloc
{
private:
 Sql_cmd(const Sql_cmd &); // No copy constructor wanted
 void operator=(Sql_cmd &); // No assignment operator wanted

public:
 /**
 @brief Return the command code for this statement
 */
 virtual enum_sql_command sql_command_code() const = 0;

protected:
 Sql_cmd()
 {}

 virtual ~Sql_cmd()
 {
 /*
 Sql_cmd objects are allocated in thd->mem_root.
 In MySQL, the C++ destructor is never called, the underlying MEM_ROOT is
 simply destroyed instead.
 Do not rely on the destructor for any cleanup.
 */
 DBUG_ASSERT(FALSE);
 }
};

#endif // SQL_CMD_INCLUDED