includes/SearchIBM_DB2.php

   1 <?php
   2 # Copyright (C) 2004 Brion Vibber <brion@pobox.com>
   3 # http://www.mediawiki.org/
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; either version 2 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License along
  16 # with this program; if not, write to the Free Software Foundation, Inc.,
  17 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18 # http://www.gnu.org/copyleft/gpl.html
  19
  20 /**
  21  * @file
  22  * @ingroup Search
  23  */
  24
  25 /**
  26  * Search engine hook base class for IBM DB2
  27  * @ingroup Search
  28  */
  29 class SearchIBM_DB2 extends SearchEngine {
  30         function __construct($db) {
  31                 $this->db = $db;
  32         }
  33
  34         /**
  35          * Perform a full text search query and return a result set.
  36          *
  37          * @param $term String: raw search term
  38          * @return IBM_DB2SearchResultSet
  39          */
  40         function searchText( $term ) {
  41                 $resultSet = $this->db->resultObject($this->db->query($this->getQuery($this->filter($term), true)));
  42                 return new IBM_DB2SearchResultSet($resultSet, $this->searchTerms);
  43         }
  44
  45         /**
  46          * Perform a title-only search query and return a result set.
  47          *
  48          * @param $term String: taw search term
  49          * @return IBM_DB2SearchResultSet
  50          */
  51         function searchTitle($term) {
  52                 $resultSet = $this->db->resultObject($this->db->query($this->getQuery($this->filter($term), false)));
  53                 return new MySQLSearchResultSet($resultSet, $this->searchTerms);
  54         }
  55
  56
  57         /**
  58          * Return a partial WHERE clause to exclude redirects, if so set
  59          * @return String
  60          */
  61         function queryRedirect() {
  62                 if ($this->showRedirects) {
  63                         return '';
  64                 } else {
  65                         return 'AND page_is_redirect=0';
  66                 }
  67         }
  68
  69         /**
  70          * Return a partial WHERE clause to limit the search to the given namespaces
  71          * @return String
  72          */
  73         function queryNamespaces() {
  74                 if( is_null($this->namespaces) )
  75                         return '';
  76                 $namespaces = implode(',', $this->namespaces);
  77                 if ($namespaces == '') {
  78                         $namespaces = '0';
  79                 }
  80                 return 'AND page_namespace IN (' . $namespaces . ')';
  81         }
  82
  83         /**
  84          * Return a LIMIT clause to limit results on the query.
  85          * @return String
  86          */
  87         function queryLimit($sql) {
  88                 return $this->db->limitResult($sql, $this->limit, $this->offset);
  89         }
  90
  91         /**
  92          * Does not do anything for generic search engine
  93          * subclasses may define this though
  94          * @return String
  95          */
  96         function queryRanking($filteredTerm, $fulltext) {
  97                 // requires Net Search Extender or equivalent
  98                 // return ' ORDER BY score(1)';
  99                 return '';
 100         }
 101
 102         /**
 103          * Construct the full SQL query to do the search.
 104          * The guts shoulds be constructed in queryMain()
 105          * @param string $filteredTerm String
 106          * @param bool $fulltext Boolean
 107          */
 108         function getQuery( $filteredTerm, $fulltext ) {
 109                 return $this->queryLimit($this->queryMain($filteredTerm, $fulltext) . ' ' .
 110                         $this->queryRedirect() . ' ' .
 111                         $this->queryNamespaces() . ' ' .
 112                         $this->queryRanking( $filteredTerm, $fulltext ) . ' ');
 113         }
 114
 115
 116         /**
 117          * Picks which field to index on, depending on what type of query.
 118          * @param $fulltext Boolean
 119          * @return String
 120          */
 121         function getIndexField($fulltext) {
 122                 return $fulltext ? 'si_text' : 'si_title';
 123         }
 124
 125         /**
 126          * Get the base part of the search query.
 127          *
 128          * @param string $filteredTerm String
 129          * @param bool $fulltext Boolean
 130          * @return String
 131          */
 132         function queryMain( $filteredTerm, $fulltext ) {
 133                 $match = $this->parseQuery($filteredTerm, $fulltext);
 134                 $page        = $this->db->tableName('page');
 135                 $searchindex = $this->db->tableName('searchindex');
 136                 return 'SELECT page_id, page_namespace, page_title ' .
 137                         "FROM $page,$searchindex " .
 138                         'WHERE page_id=si_page AND ' . $match;
 139         }
 140
 141         /** @todo document */
 142         function parseQuery($filteredText, $fulltext) {
 143                 global $wgContLang;
 144                 $lc = SearchEngine::legalSearchChars();
 145                 $this->searchTerms = array();
 146
 147                 # FIXME: This doesn't handle parenthetical expressions.
 148                 $m = array();
 149                 $q = array();
 150
 151                 if (preg_match_all('/([-+<>~]?)(([' . $lc . ']+)(\*?)|"[^"]*")/',
 152                           $filteredText, $m, PREG_SET_ORDER)) {
 153                         foreach($m as $terms) {
 154                                 $q[] = $terms[1] . $wgContLang->stripForSearch($terms[2]);
 155
 156                                 if (!empty($terms[3])) {
 157                                         $regexp = preg_quote( $terms[3], '/' );
 158                                         if ($terms[4])
 159                                                 $regexp .= "[0-9A-Za-z_]+";
 160                                 } else {
 161                                         $regexp = preg_quote(str_replace('"', '', $terms[2]), '/');
 162                                 }
 163                                 $this->searchTerms[] = $regexp;
 164                         }
 165                 }
 166
 167                 $searchon = $this->db->strencode(join(',', $q));
 168                 $field = $this->getIndexField($fulltext);
 169
 170                 // requires Net Search Extender or equivalent
 171                 //return " CONTAINS($field, '$searchon') > 0 ";
 172
 173                 return " lcase($field) LIKE lcase('%$searchon%')";
 174         }
 175
 176         /**
 177          * Create or update the search index record for the given page.
 178          * Title and text should be pre-processed.
 179          *
 180          * @param $id Integer
 181          * @param $title String
 182          * @param $text String
 183          */
 184         function update($id, $title, $text) {
 185                 $dbw = wfGetDB(DB_MASTER);
 186                 $dbw->replace('searchindex',
 187                         array('si_page'),
 188                         array(
 189                                 'si_page' => $id,
 190                                 'si_title' => $title,
 191                                 'si_text' => $text
 192                         ), 'SearchIBM_DB2::update' );
 193                 // ?
 194                 //$dbw->query("CALL ctx_ddl.sync_index('si_text_idx')");
 195                 //$dbw->query("CALL ctx_ddl.sync_index('si_title_idx')");
 196         }
 197
 198         /**
 199          * Update a search index record's title only.
 200          * Title should be pre-processed.
 201          *
 202          * @param $id Integer
 203          * @param $title String
 204          */
 205         function updateTitle($id, $title) {
 206                 $dbw = wfGetDB(DB_MASTER);
 207
 208                 $dbw->update('searchindex',
 209                         array('si_title' => $title),
 210                         array('si_page'  => $id),
 211                         'SearchIBM_DB2::updateTitle',
 212                         array());
 213         }
 214 }
 215
 216 /**
 217  * @ingroup Search
 218  */
 219 class IBM_DB2SearchResultSet extends SearchResultSet {
 220         function __construct($resultSet, $terms) {
 221                 $this->mResultSet = $resultSet;
 222                 $this->mTerms = $terms;
 223         }
 224
 225         function termMatches() {
 226                 return $this->mTerms;
 227         }
 228
 229         function numRows() {
 230                 return $this->mResultSet->numRows();
 231         }
 232
 233         function next() {
 234                 $row = $this->mResultSet->fetchObject();
 235                 if ($row === false)
 236                         return false;
 237                 return new SearchResult($row);
 238         }
 239 }