~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, Inc.

 *

 *  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/session.h"

#include "drizzled/statement/rollback_to_savepoint.h"

#include "drizzled/transaction_services.h"

#include "drizzled/named_savepoint.h"

#include "drizzled/util/functors.h"

#include <string>

using namespace std;

namespace drizzled

{

bool statement::RollbackToSavepoint::execute()

{

  /*

   * If AUTOCOMMIT is off and resource contexts are empty then we need

   * to start a transaction. It will be empty when ROLLBACK TO SAVEPOINT

   * starts the transaction. Table affecting statements do this work in

   * lockTables() by calling startStatement().

   */

  if ( (session->options & OPTION_NOT_AUTOCOMMIT) &&

       (session->transaction.all.getResourceContexts().empty() == true) )

  {

    if (session->startTransaction() == false)

    {

      return false;

    }

  }

  /*

   * Handle these situations:

   *

   * If the first savepoint on the deck matches the

   * name to find, simply call rollback_to_savepoint

   * for the resource managers.

   *

   * If the first savepoint on the deck does NOT match

   * the name to find, then we need to search through

   * the deque to find the savepoint we need.  If we

   * don't find it, we return an error.  If we do

   * find it, we must restructure the deque by removing

   * all savepoints "above" the one we find.

   */

  deque<NamedSavepoint> &savepoints= session->transaction.savepoints;

  TransactionServices &transaction_services= TransactionServices::singleton();

  /* Short-circuit for no savepoints */

  if (savepoints.empty())

  {

    my_error(ER_SP_DOES_NOT_EXIST, 

             MYF(0), 

             "SAVEPOINT", 

             session->lex->ident.str);

    return false;

  }

  {

    /* Short-circuit for first savepoint */

    NamedSavepoint &first_savepoint= savepoints.front();

    const string &first_savepoint_name= first_savepoint.getName();

    if (my_strnncoll(system_charset_info,

                     (unsigned char *) session->lex->ident.str, 

                     session->lex->ident.length,

                     (unsigned char *) first_savepoint_name.c_str(), 

                     first_savepoint_name.size()) == 0)

    {

      /* Found the named savepoint we want to rollback to */

      (void) transaction_services.rollbackToSavepoint(session, first_savepoint);

      if (session->transaction.all.hasModifiedNonTransData())

      {

        push_warning(session, 

                     DRIZZLE_ERROR::WARN_LEVEL_WARN,

                     ER_WARNING_NOT_COMPLETE_ROLLBACK,

                     ER(ER_WARNING_NOT_COMPLETE_ROLLBACK));

      }

      session->my_ok();

      return false;

    }

  }

  /* 

   * OK, from here on out it means that we have savepoints

   * but that the first savepoint isn't the one we're looking

   * for.  We need to search through the savepoints and find

   * the one we're looking for, removing all savepoints "above"

   * the one we need.

   */

  bool found= false;

  deque<NamedSavepoint> copy_savepoints(savepoints); /* used to restore if not found */

  deque<NamedSavepoint> new_savepoints;

  while (savepoints.empty() == false)

  {

    NamedSavepoint &sv= savepoints.front();

    const string &sv_name= sv.getName();

    if (! found && 

        my_strnncoll(system_charset_info,

                     (unsigned char *) session->lex->ident.str, 

                     session->lex->ident.length,

                     (unsigned char *) sv_name.c_str(), 

                     sv_name.size()) == 0)

    {

      /* Found the named savepoint we want to rollback to */

      found= true;

      (void) transaction_services.rollbackToSavepoint(session, sv);

    }

    if (found)

    {

      /* 

       * We push all savepoints "below" the found savepoint

       * to our new savepoint list, in reverse order to keep

       * the stack order correct. 

       */

      new_savepoints.push_back(sv);

    }

    savepoints.pop_front();

  }

  if (found)

  {

    if (session->transaction.all.hasModifiedNonTransData())

    {

      push_warning(session, 

                   DRIZZLE_ERROR::WARN_LEVEL_WARN,

                   ER_WARNING_NOT_COMPLETE_ROLLBACK,

                   ER(ER_WARNING_NOT_COMPLETE_ROLLBACK));

    }

    /* Store new savepoints list */

    session->transaction.savepoints= new_savepoints;

    session->my_ok();

  }

  else

  {

    /* restore the original savepoint list */

    session->transaction.savepoints= copy_savepoints;

    my_error(ER_SP_DOES_NOT_EXIST, 

             MYF(0), 

             "SAVEPOINT", 

             session->lex->ident.str);

  }

  return false;

}

} /* namespace drizzled */