<?php

/*

 You may not change or alter any portion of this comment or credits

 of supporting developers from this source code or any supporting source code

 which is considered copyrighted (c) material of the original comment or credit authors.



 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.

*/



/**

 * Object synchronization handler class.

 *

 * @copyright       The XOOPS Project http://sourceforge.net/projects/xoops/

 * @license         GNU GPL 2 (http://www.gnu.org/licenses/old-licenses/gpl-2.0.html)

 * @package         class

 * @subpackage      model

 * @since           2.3.0

 * @author          Taiwen Jiang <phppp@users.sourceforge.net>

 * @version         $Id: sync.php 8271 2011-11-11 19:46:00Z trabis $

 */



defined('XOOPS_ROOT_PATH') or die('Restricted access');



/**

 * Object synchronization handler class.

 *

 * @author Taiwen Jiang <phppp@users.sourceforge.net>

 *

 * {@link XoopsObjectAbstract}

 *

 * Usage of methods provided by XoopsModelSync:

 *

 * Step #1: set linked table and adjoint fields through XoopsPersistableObjectHandler:

 *                  $handler->table_link = $handler->db->prefix("the_linked_table"); // full name of the linked table that is used for the query

 *                  $handler->field_link = "the_linked_field"; // name of field in linked table that will be used to link the linked table with current table

 *                  $handler->field_object = "the_object_field"; // name of field in current table that will be used to link the linked table with current table; linked field name will be used if the field name is not set

 * Step #2: perform query

 */

class XoopsModelSync extends XoopsModelAbstract

{

    /**

     * Clean orphan objects against linked objects

     *

     * @param string $table_link table of linked object for JOIN; deprecated, for backward compat

     * @param string $field_link field of linked object for JOIN; deprecated, for backward compat

     * @param string $field_object field of current object for JOIN; deprecated, for backward compat

     * @return bool true on success

     */

    public function cleanOrphan($table_link = '', $field_link = '', $field_object = '')

    {

        if (!empty($table_link)) {

            $this->handler->table_link = $table_link;

        }

        if (!empty($field_link)) {

            $this->handler->field_link = $field_link;

        }

        if (!empty($field_object)) {

            $this->handler->field_object = $field_object;

        }



        if (empty($this->handler->field_object) || empty($this->handler->table_link) || empty($this->handler->field_link)) {

            trigger_error("The link information is not set for '" . get_class($this->handler) . "' yet.", E_USER_WARNING);

            return null;

        }



        /**

         * for MySQL 4.1+

         */

        if (version_compare(mysql_get_server_info(), "4.1.0", "ge")) {

            $sql = "DELETE FROM `{$this->handler->table}`"

                 . " WHERE (`{$this->handler->field_object}` NOT IN ( SELECT DISTINCT `{$this->handler->field_link}` FROM `{$this->handler->table_link}`) )";

        } else {

            // for 4.0+

            $sql = "DELETE `{$this->handler->table}` FROM `{$this->handler->table}`"

                 . " LEFT JOIN `{$this->handler->table_link}` AS aa ON `{$this->handler->table}`.`{$this->handler->field_object}` = aa.`{$this->handler->field_link}`"

                 . " WHERE (aa.`{$this->handler->field_link}` IS NULL)";

        }

        if (!$this->handler->db->queryF($sql)) {

            return false;

        }

        return true;

    }

}