#ifndef SQL_TRUNCATE_INCLUDED
#define SQL_TRUNCATE_INCLUDED
/* Copyright (c) 2010, 2015, 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, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   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, version 2.0, 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 */

#include "my_global.h"
#include "sql_cmd_dml.h"          // Sql_cmd_dml

class MDL_ticket;
class THD;
struct TABLE_LIST;

/**
  Sql_cmd_truncate_table represents the TRUNCATE statement.
*/
class Sql_cmd_truncate_table : public Sql_cmd_dml
{
private:
  /* Set if a lock must be downgraded after truncate is done. */
  MDL_ticket *m_ticket_downgrade;

public:
  /**
    Constructor, used to represent a TRUNCATE statement.
  */
  Sql_cmd_truncate_table()
  {}

  virtual ~Sql_cmd_truncate_table()
  {}

  /**
    Execute a TRUNCATE statement at runtime.
    @param thd the current thread.
    @return false on success.
  */
  bool execute(THD *thd);

  virtual enum_sql_command sql_command_code() const
  {
    return SQLCOM_TRUNCATE;
  }

  virtual bool prepared_statement_test(THD *) { return false; }
  virtual bool prepare(THD *) { return false; }
  virtual void cleanup(THD *) {}

protected:
  enum truncate_result{
    TRUNCATE_OK=0,
    TRUNCATE_FAILED_BUT_BINLOG,
    TRUNCATE_FAILED_SKIP_BINLOG
  };

  /** Handle locking a base table for truncate. */
  bool lock_table(THD *, TABLE_LIST *, bool *);

  /** Truncate table via the handler method. */
  enum truncate_result handler_truncate(THD *, TABLE_LIST *, bool);

  /**
    Optimized delete of all rows by doing a full regenerate of the table.
    Depending on the storage engine, it can be accomplished through a
    drop and recreate or via the handler truncate method.
  */
  bool truncate_table(THD *, TABLE_LIST *);
};

#endif
