phpBB

<?php

/**

*

* @package search

* @version $Id$

* @copyright (c) 2005 phpBB Group

* @license http://opensource.org/licenses/gpl-license.php GNU Public License

*

*/

/**

* @ignore

*/

if (!defined('IN_PHPBB'))

{

        exit;

}

/**

* @ignore

*/

define('SEARCH_RESULT_NOT_IN_CACHE', 0);

define('SEARCH_RESULT_IN_CACHE', 1);

define('SEARCH_RESULT_INCOMPLETE', 2);

/**

* search_backend

* optional base class for search plugins providing simple caching based on ACM

* and functions to retrieve ignore_words and synonyms

* @package search

*/

class search_backend

{

        var $ignore_words = array();

        var $match_synonym = array();

        var $replace_synonym = array();

        function search_backend(&$error)

        {

                // This class cannot be used as a search plugin

                $error = true;

        }

        /**

        * Retrieves a language dependend list of words that should be ignored by the search

        */

        function get_ignore_words()

        {

                if (!sizeof($this->ignore_words))

                {

                        global $user, $phpEx;

                        $words = array();

                        if (file_exists("{$user->lang_path}{$user->lang_name}/search_ignore_words.$phpEx"))

                        {

                                // include the file containing ignore words

                                include("{$user->lang_path}{$user->lang_name}/search_ignore_words.$phpEx");

                        }

                        $this->ignore_words = $words;

                        unset($words);

                }

        }

        /**

        * Stores a list of synonyms that should be replaced in $this->match_synonym and $this->replace_synonym and caches them

        */

        function get_synonyms()

        {

                if (!sizeof($this->match_synonym))

                {

                        global $user, $phpEx;

                        $synonyms = array();

                        if (file_exists("{$user->lang_path}{$user->lang_name}/search_synonyms.$phpEx"))

                        {

                                // include the file containing synonyms

                                include("{$user->lang_path}{$user->lang_name}/search_synonyms.$phpEx");

                        }

                        $this->match_synonym = array_keys($synonyms);

                        $this->replace_synonym = array_values($synonyms);

                        unset($synonyms);

                }

        }

        /**

        * Retrieves cached search results

        *

        * @param int &$result_count will contain the number of all results for the search (not only for the current page)

        * @param array &$id_ary is filled with the ids belonging to the requested page that are stored in the cache

        *

        * @return int SEARCH_RESULT_NOT_IN_CACHE or SEARCH_RESULT_IN_CACHE or SEARCH_RESULT_INCOMPLETE

        */

        function obtain_ids($search_key, &$result_count, &$id_ary, $start, $per_page, $sort_dir)

        {

                global $cache;

                if (!($stored_ids = $cache->get('_search_results_' . $search_key)))

                {

                        // no search results cached for this search_key

                        return SEARCH_RESULT_NOT_IN_CACHE;

                }

                else

                {

                        $result_count = $stored_ids[-1];

                        $reverse_ids = ($stored_ids[-2] != $sort_dir) ? true : false;

                        $complete = true;

                        // change the start to the actual end of the current request if the sort direction differs

                        // from the dirction in the cache and reverse the ids later

                        if ($reverse_ids)

                        {

                                $start = $result_count - $start - $per_page;

                                // the user requested a page past the last index

                                if ($start < 0)

                                {

                                        return SEARCH_RESULT_NOT_IN_CACHE;

                                }

                        }

                        for ($i = $start, $n = $start + $per_page; ($i < $n) && ($i < $result_count); $i++)

                        {

                                if (!isset($stored_ids[$i]))

                                {

                                        $complete = false;

                                }

                                else

                                {

                                        $id_ary[] = $stored_ids[$i];

                                }

                        }

                        unset($stored_ids);

                        if ($reverse_ids)

                        {

                                $id_ary = array_reverse($id_ary);

                        }

                        if (!$complete)

                        {

                                return SEARCH_RESULT_INCOMPLETE;

                        }

                        return SEARCH_RESULT_IN_CACHE;

                }

        }

        /**

        * Caches post/topic ids

        *

        * @param array &$id_ary contains a list of post or topic ids that shall be cached, the first element

        *         must have the absolute index $start in the result set.

        */

        function save_ids($search_key, $keywords, $author_ary, $result_count, &$id_ary, $start, $sort_dir)

        {

                global $cache, $config, $db, $user;

                $length = min(sizeof($id_ary), $config['search_block_size']);

                // nothing to cache so exit

                if (!$length)

                {

                        return;

                }

                $store_ids = array_slice($id_ary, 0, $length);

                // create a new resultset if there is none for this search_key yet

                // or add the ids to the existing resultset

                if (!($store = $cache->get('_search_results_' . $search_key)))

                {

                        // add the current keywords to the recent searches in the cache which are listed on the search page

                        if (!empty($keywords) || sizeof($author_ary))

                        {

                                $sql = 'SELECT search_time

                                        FROM ' . SEARCH_RESULTS_TABLE . '

                                        WHERE search_key = \'' . $db->sql_escape($search_key) . '\'';

                                $result = $db->sql_query($sql);

                                if (!$db->sql_fetchrow($result))

                                {

                                        $sql_ary = array(

                                                'search_key'                => $search_key,

                                                'search_time'                => time(),

                                                'search_keywords'        => $keywords,

                                                'search_authors'        => ' ' . implode(' ', $author_ary) . ' '

                                        );

                                        $sql = 'INSERT INTO ' . SEARCH_RESULTS_TABLE . ' ' . $db->sql_build_array('INSERT', $sql_ary);

                                        $db->sql_query($sql);

                                }

                                $db->sql_freeresult($result);

                        }

                        $sql = 'UPDATE ' . USERS_TABLE . '

                                SET user_last_search = ' . time() . '

                                WHERE user_id = ' . $user->data['user_id'];

                        $db->sql_query($sql);

                        $store = array(-1 => $result_count, -2 => $sort_dir);

                        $id_range = range($start, $start + $length - 1);

                }

                else

                {

                        // we use one set of results for both sort directions so we have to calculate the indizes

                        // for the reversed array and we also have to reverse the ids themselves

                        if ($store[-2] != $sort_dir)

                        {

                                $store_ids = array_reverse($store_ids);

                                $id_range = range($store[-1] - $start - $length, $store[-1] - $start - 1);

                        }

                        else

                        {

                                $id_range = range($start, $start + $length - 1);

                        }

                }

                $store_ids = array_combine($id_range, $store_ids);

                // append the ids

                if (is_array($store_ids))

                {

                        $store += $store_ids;

                        // if the cache is too big

                        if (sizeof($store) - 2 > 20 * $config['search_block_size'])

                        {

                                // remove everything in front of two blocks in front of the current start index

                                for ($i = 0, $n = $id_range[0] - 2 * $config['search_block_size']; $i < $n; $i++)

                                {

                                        if (isset($store[$i]))

                                        {

                                                unset($store[$i]);

                                        }

                                }

                                // remove everything after two blocks after the current stop index

                                end($id_range);

                                for ($i = $store[-1] - 1, $n = current($id_range) + 2 * $config['search_block_size']; $i > $n; $i--)

                                {

                                        if (isset($store[$i]))

                                        {

                                                unset($store[$i]);

                                        }

                                }

                        }

                        $cache->put('_search_results_' . $search_key, $store, $config['search_store_results']);

                        $sql = 'UPDATE ' . SEARCH_RESULTS_TABLE . '

                                SET search_time = ' . time() . '

                                WHERE search_key = \'' . $db->sql_escape($search_key) . '\'';

                        $db->sql_query($sql);

                }

                unset($store);

                unset($store_ids);

                unset($id_range);

        }

        /**

        * Removes old entries from the search results table and removes searches with keywords that contain a word in $words.

        */

        function destroy_cache($words, $authors = false)

        {

                global $db, $cache, $config;

                // clear all searches that searched for the specified words

                if (sizeof($words))

                {

                        $sql_where = '';

                        foreach ($words as $word)

                        {

                                $sql_where .= " OR search_keywords " . $db->sql_like_expression($db->any_char . $word . $db->any_char);

                        }

                        $sql = 'SELECT search_key

                                FROM ' . SEARCH_RESULTS_TABLE . "

                                WHERE search_keywords LIKE '%*%' $sql_where";

                        $result = $db->sql_query($sql);

                        while ($row = $db->sql_fetchrow($result))

                        {

                                $cache->destroy('_search_results_' . $row['search_key']);

                        }

                        $db->sql_freeresult($result);

                }

                // clear all searches that searched for the specified authors

                if (is_array($authors) && sizeof($authors))

                {

                        $sql_where = '';

                        foreach ($authors as $author)

                        {

                                $sql_where .= (($sql_where) ? ' OR ' : '') . 'search_authors LIKE \'% ' . (int) $author . ' %\'';

                        }

                        $sql = 'SELECT search_key

                                FROM ' . SEARCH_RESULTS_TABLE . "

                                WHERE $sql_where";

                        $result = $db->sql_query($sql);

                        while ($row = $db->sql_fetchrow($result))

                        {

                                $cache->destroy('_search_results_' . $row['search_key']);

                        }

                        $db->sql_freeresult($result);

                }

                $sql = 'DELETE

                        FROM ' . SEARCH_RESULTS_TABLE . '

                        WHERE search_time < ' . (time() - $config['search_store_results']);

                $db->sql_query($sql);

        }

}

?>