<?php

/*

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * This software consists of voluntary contributions made by many individuals

 * and is licensed under the LGPL. For more information, see

 * <http://www.doctrine-project.org>.

 */

namespace Doctrine\ORM\Id;

use Doctrine\ORM\EntityManager;

/**

 * Id generator that uses a single-row database table and a hi/lo algorithm.

 *

 * @since   2.0

 * @author  Benjamin Eberlei <kontakt@beberlei.de>

 * @author  Guilherme Blanco <guilhermeblanco@hotmail.com>

 * @author  Jonathan Wage <jonwage@gmail.com>

 * @author  Roman Borschel <roman@code-factory.org>

 */

class TableGenerator extends AbstractIdGenerator

{

    private $_tableName;

    private $_sequenceName;

    private $_allocationSize;

    private $_nextValue;

    private $_maxValue;

    public function __construct($tableName, $sequenceName = 'default', $allocationSize = 10)

    {

        $this->_tableName = $tableName;

        $this->_sequenceName = $sequenceName;

        $this->_allocationSize = $allocationSize;

    }

    public function generate(EntityManager $em, $entity)

    {

        if ($this->_maxValue === null || $this->_nextValue == $this->_maxValue) {

            // Allocate new values

            $conn = $em->getConnection();

            if ($conn->getTransactionNestingLevel() == 0) {

                // use select for update

                $sql = $conn->getDatabasePlatform()->getTableHiLoCurrentValSql($this->_tableName, $this->_sequenceName);

                $currentLevel = $conn->fetchColumn($sql);

                if ($currentLevel != null) {

                    $this->_nextValue = $currentLevel;

                    $this->_maxValue = $this->_nextValue + $this->_allocationSize;

                    $updateSql = $conn->getDatabasePlatform()->getTableHiLoUpdateNextValSql(

                        $this->_tableName, $this->_sequenceName, $this->_allocationSize

                    );

                    if ($conn->executeUpdate($updateSql, array(1 => $currentLevel, 2 => $currentLevel+1)) !== 1) {

                        // no affected rows, concurrency issue, throw exception

                    }

                } else {

                    // no current level returned, TableGenerator seems to be broken, throw exception

                }

            } else {

                // only table locks help here, implement this or throw exception?

                // or do we want to work with table locks exclusively?

            }

        }

        return $this->_nextValue++;

    }

}