~drizzle-trunk/drizzle/development

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

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

 *

 *  Copyright (C) 2009 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; either version 2 of the License, or

 *  (at your option) any later version.

 *

 *  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 <drizzled/show.h>

#include <drizzled/lock.h>

#include <drizzled/session.h>

#include <drizzled/statement/create_table.h>

#include <drizzled/table_identifier.h>

namespace drizzled

{

bool statement::CreateTable::execute()

{

  TableList *first_table= (TableList *) session->lex->select_lex.table_list.first;

  TableList *all_tables= session->lex->query_tables;

  assert(first_table == all_tables && first_table != 0);

  Select_Lex *select_lex= &session->lex->select_lex;

  Select_Lex_Unit *unit= &session->lex->unit;

  bool need_start_waiting= false;

  bool res= false;

  bool link_to_local= false;

  bool lex_identified_temp_table= 

    create_table_proto.type() == drizzled::message::Table::TEMPORARY;

  if (is_engine_set)

  {

    create_info.db_type= 

      plugin::StorageEngine::findByName(*session, create_table_proto.engine().name());

    if (create_info.db_type == NULL)

    {

      my_error(ER_UNKNOWN_STORAGE_ENGINE, MYF(0), 

               create_table_proto.name().c_str());

      return true;

    }

  }

  else /* We now get the default, place it in create_info, and put the engine name in table proto */

  {

    create_info.db_type= session->getDefaultStorageEngine();

  }

  /* 

    Now we set the name in our Table proto so that it will match 

    create_info.db_type.

  */

  {

    message::Table::StorageEngine *protoengine;

    protoengine= create_table_proto.mutable_engine();

    protoengine->set_name(create_info.db_type->getName());

  }

  /* If CREATE TABLE of non-temporary table, do implicit commit */

  if (! lex_identified_temp_table)

  {

    if (! session->endActiveTransaction())

    {

      return true;

    }

  }

  /* Skip first table, which is the table we are creating */

  TableList *create_table= session->lex->unlink_first_table(&link_to_local);

  TableList *select_tables= session->lex->query_tables;

  /*

    Now that we have the engine, we can figure out the table identifier. We need the engine in order

    to determine if the table is transactional or not if it is temp.

  */

  TableIdentifier new_table_identifier(create_table->db,

                                       create_table->table_name,

                                       create_table_proto.type() != message::Table::TEMPORARY ? NO_TMP_TABLE : TEMP_TABLE);

  if (create_table_precheck(new_table_identifier))

  {

    /* put tables back for PS rexecuting */

    session->lex->link_first_table_back(create_table, link_to_local);

    return true;

  }

  /* Might have been updated in create_table_precheck */

  create_info.alias= create_table->alias;

  /*

     The create-select command will open and read-lock the select table

     and then create, open and write-lock the new table. If a global

     read lock steps in, we get a deadlock. The write lock waits for

     the global read lock, while the global read lock waits for the

     select table to be closed. So we wait until the global readlock is

     gone before starting both steps. Note that

     wait_if_global_read_lock() sets a protection against a new global

     read lock when it succeeds. This needs to be released by

     start_waiting_global_read_lock(). We protect the normal CREATE

     TABLE in the same way. That way we avoid that a new table is

     created during a gobal read lock.

   */

  if (! (need_start_waiting= ! wait_if_global_read_lock(session, 0, 1)))

  {

    /* put tables back for PS rexecuting */

    session->lex->link_first_table_back(create_table, link_to_local);

    return true;

  }

  if (select_lex->item_list.elements)		// With select

  {

    select_result *result;

    select_lex->options|= SELECT_NO_UNLOCK;

    unit->set_limit(select_lex);

    if (! lex_identified_temp_table)

    {

      session->lex->link_first_table_back(create_table, link_to_local);

      create_table->create= true;

    }

    if (! (res= session->openTablesLock(session->lex->query_tables)))

    {

      /*

         Is table which we are changing used somewhere in other parts

         of query

       */

      if (! lex_identified_temp_table)

      {

        TableList *duplicate= NULL;

        create_table= session->lex->unlink_first_table(&link_to_local);

        if ((duplicate= unique_table(create_table, select_tables)))

        {

          my_error(ER_UPDATE_TABLE_USED, MYF(0), create_table->alias);

          /*

             Release the protection against the global read lock and wake

             everyone, who might want to set a global read lock.

           */

          start_waiting_global_read_lock(session);

          /* put tables back for PS rexecuting */

          session->lex->link_first_table_back(create_table, link_to_local);

          return true;

        }

      }

      /*

         select_create is currently not re-execution friendly and

         needs to be created for every execution of a PS/SP.

       */

      if ((result= new select_create(create_table,

                                     is_if_not_exists,

                                     &create_info,

                                     &create_table_proto,

                                     &alter_info,

                                     select_lex->item_list,

                                     session->lex->duplicates,

                                     session->lex->ignore,

                                     select_tables)))

      {

        /*

           CREATE from SELECT give its Select_Lex for SELECT,

           and item_list belong to SELECT

         */

        res= handle_select(session, session->lex, result, 0);

        delete result;

      }

    }

    else if (! lex_identified_temp_table)

    {

      create_table= session->lex->unlink_first_table(&link_to_local);

    }

  }

  else

  {

    /* regular create */

    if (is_create_table_like)

    {

      res= mysql_create_like_table(session, 

                                   create_table, 

                                   select_tables,

                                   create_table_proto,

                                   create_info.db_type, 

                                   is_if_not_exists,

                                   is_engine_set);

    }

    else

    {

      for (int32_t x= 0; x < alter_info.alter_proto.added_field_size(); x++)

      {

        message::Table::Field *field= create_table_proto.add_field();

        *field= alter_info.alter_proto.added_field(x);

      }

      res= mysql_create_table(session, 

                              new_table_identifier,

                              &create_info,

                              &create_table_proto,

                              &alter_info, 

                              false, 

                              0,

                              is_if_not_exists);

    }

    if (! res)

    {

      session->my_ok();

    }

  }

  /*

     Release the protection against the global read lock and wake

     everyone, who might want to set a global read lock.

   */

  start_waiting_global_read_lock(session);

  return res;

}

} /* namespace drizzled */