~drizzle-trunk/drizzle/development

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-

 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:

 *

 *  Copyright (C) 2008 Sun Microsystems

 *

 *  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

 */

#include "config.h"

#include <boost/lexical_cast.hpp>

#include <string>

#include "drizzled/session.h"

#include "drizzled/item/string.h"

#include "drizzled/sql_list.h"

using namespace std;

namespace drizzled

{

/**

  Execute update of all variables.

  First run a check of all variables that all updates will go ok.

  If yes, then execute all updates, returning an error if any one failed.

  This should ensure that in all normal cases none all or variables are

  updated.

  @param Session		Thread id

  @param var_list       List of variables to update

  @retval

    0	ok

  @retval

    1	ERROR, message sent (normally no variables was updated)

  @retval

    -1  ERROR, message not sent

*/

int sql_set_variables(Session *session, List<set_var_base> *var_list)

{

  int error;

  List_iterator_fast<set_var_base> it(*var_list);

  set_var_base *var;

  while ((var=it++))

  {

    if ((error= var->check(session)))

      goto err;

  }

  if (!(error= test(session->is_error())))

  {

    it.rewind();

    while ((var= it++))

      error|= var->update(session);         // Returns 0, -1 or 1

  }

err:

  free_underlaid_joins(session, &session->lex->select_lex);

  return(error);

}

/*****************************************************************************

  Functions to handle SET mysql_internal_variable=const_expr

*****************************************************************************/

set_var::set_var(sql_var_t type_arg, sys_var *var_arg,

                 const LEX_STRING *base_name_arg, Item *value_arg) :

  var(var_arg), type(type_arg), base(*base_name_arg)

{

  /*

    If the set value is a field, change it to a string to allow things like

    SET table_type=MYISAM;

  */

  if (value_arg && value_arg->type() == Item::FIELD_ITEM)

  {

    Item_field *item= (Item_field*) value_arg;

    if (!(value=new Item_string(item->field_name,

                                (uint32_t) strlen(item->field_name),

                                item->collation.collation)))

      value=value_arg;			/* Give error message later */

  }

  else

    value=value_arg;

}

int set_var::check(Session *session)

{

  if (var->is_readonly())

  {

    my_error(ER_INCORRECT_GLOBAL_LOCAL_VAR, MYF(0), var->getName().c_str(), "read only");

    return -1;

  }

  if (var->check_type(type))

  {

    int err= type == OPT_GLOBAL ? ER_LOCAL_VARIABLE : ER_GLOBAL_VARIABLE;

    my_error(err, MYF(0), var->getName().c_str());

    return -1;

  }

  /* value is a NULL pointer if we are using SET ... = DEFAULT */

  if (!value)

  {

    if (var->check_default(type))

    {

      my_error(ER_NO_DEFAULT, MYF(0), var->getName().c_str());

      return -1;

    }

    return 0;

  }

  if ((!value->fixed &&

       value->fix_fields(session, &value)) || value->check_cols(1))

    return -1;

  if (var->check_update_type(value->result_type()))

  {

    my_error(ER_WRONG_TYPE_FOR_VAR, MYF(0), var->getName().c_str());

    return -1;

  }

  return var->check(session, this) ? -1 : 0;

}

/**

  Update variable

  @param   session    thread handler

  @returns 0|1    ok or	ERROR

  @note ERROR can be only due to abnormal operations involving

  the server's execution evironment such as

  out of memory, hard disk failure or the computer blows up.

  Consider set_var::check() method if there is a need to return

  an error due to logics.

*/

int set_var::update(Session *session)

{

  try

  {

    if (! value)

      var->set_default(session, type);

    else if (var->update(session, this))

      return -1;				// should never happen

    if (var->getAfterUpdateTrigger())

      (*var->getAfterUpdateTrigger())(session, type);

  }

  catch (boost::exception &)

  {

    /* TODO: Fix this to be typesafe once we have properly typed set_var */

    string new_val= boost::lexical_cast<string>(save_result.uint32_t_value);

    push_warning_printf(session, DRIZZLE_ERROR::WARN_LEVEL_ERROR,

                        ER_TRUNCATED_WRONG_VALUE,

                        ER(ER_TRUNCATED_WRONG_VALUE), var->getName().c_str(),

                        new_val.c_str());

  }

  return 0;

}

/*****************************************************************************

  Functions to handle SET @user_variable=const_expr

*****************************************************************************/

int set_var_user::check(Session *session)

{

  /*

    Item_func_set_user_var can't substitute something else on its place =>

    0 can be passed as last argument (reference on item)

  */

  return (user_var_item->fix_fields(session, (Item**) 0) ||

	  user_var_item->check(0)) ? -1 : 0;

}

int set_var_user::update(Session *)

{

  if (user_var_item->update())

  {

    /* Give an error if it's not given already */

    my_message(ER_SET_CONSTANTS_ONLY, ER(ER_SET_CONSTANTS_ONLY), MYF(0));

    return -1;

  }

  return 0;

}

} /* namespace drizzled */