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 string $term - Raw search term
  38          * @return IBM_DB2SearchResultSet
  39          * @access public
  40          */
  41         function searchText( $term ) {
  42                 $resultSet = $this->db->resultObject($this->db->query($this->getQuery($this->filter($term), true)));
  43                 return new IBM_DB2SearchResultSet($resultSet, $this->searchTerms);
  44         }
  45
  46         /**
  47          * Perform a title-only search query and return a result set.
  48          *
  49          * @param string $term - Raw search term
  50          * @return IBM_DB2SearchResultSet
  51          * @access public
  52          */
  53         function searchTitle($term) {
  54                 $resultSet = $this->db->resultObject($this->db->query($this->getQuery($this->filter($term), false)));
  55                 return new MySQLSearchResultSet($resultSet, $this->searchTerms);
  56         }
  57
  58
  59         /**
  60          * Return a partial WHERE clause to exclude redirects, if so set
  61          * @return string
  62          * @private
  63          */
  64         function queryRedirect() {
  65                 if ($this->showRedirects) {
  66                         return '';
  67                 } else {
  68                         return 'AND page_is_redirect=0';
  69                 }
  70         }
  71
  72         /**
  73          * Return a partial WHERE clause to limit the search to the given namespaces
  74          * @return string
  75          * @private
  76          */
  77         function queryNamespaces() {
  78                 if( is_null($this->namespaces) )
  79                         return '';
  80                 $namespaces = implode(',', $this->namespaces);
  81                 if ($namespaces == '') {
  82                         $namespaces = '0';
  83                 }
  84                 return 'AND page_namespace IN (' . $namespaces . ')';
  85         }
  86
  87         /**
  88          * Return a LIMIT clause to limit results on the query.
  89          * @return string
  90          * @private
  91          */
  92         function queryLimit($sql) {
  93                 return $this->db->limitResult($sql, $this->limit, $this->offset);
  94         }
  95
  96         /**
  97          * Does not do anything for generic search engine
  98          * subclasses may define this though
  99          * @return string
 100          * @private
 101          */
 102         function queryRanking($filteredTerm, $fulltext) {
 103                 // requires Net Search Extender or equivalent
 104                 // return ' ORDER BY score(1)';
 105                 return '';
 106         }
 107
 108         /**
 109          * Construct the full SQL query to do the search.
 110          * The guts shoulds be constructed in queryMain()
 111          * @param string $filteredTerm
 112          * @param bool $fulltext
 113          * @private
 114          */
 115         function getQuery( $filteredTerm, $fulltext ) {
 116                 return $this->queryLimit($this->queryMain($filteredTerm, $fulltext) . ' ' .
 117                         $this->queryRedirect() . ' ' .
 118                         $this->queryNamespaces() . ' ' .
 119                         $this->queryRanking( $filteredTerm, $fulltext ) . ' ');
 120         }
 121
 122
 123         /**
 124          * Picks which field to index on, depending on what type of query.
 125          * @param bool $fulltext
 126          * @return string
 127          */
 128         function getIndexField($fulltext) {
 129                 return $fulltext ? 'si_text' : 'si_title';
 130         }
 131
 132         /**
 133          * Get the base part of the search query.
 134          *
 135          * @param string $filteredTerm
 136          * @param bool $fulltext
 137          * @return string
 138          * @private
 139          */
 140         function queryMain( $filteredTerm, $fulltext ) {
 141                 $match = $this->parseQuery($filteredTerm, $fulltext);
 142                 $page        = $this->db->tableName('page');
 143                 $searchindex = $this->db->tableName('searchindex');
 144                 return 'SELECT page_id, page_namespace, page_title ' .
 145                         "FROM $page,$searchindex " .
 146                         'WHERE page_id=si_page AND ' . $match;
 147         }
 148
 149         /** @todo document */
 150         function parseQuery($filteredText, $fulltext) {
 151                 global $wgContLang;
 152                 $lc = SearchEngine::legalSearchChars();
 153                 $this->searchTerms = array();
 154
 155                 # FIXME: This doesn't handle parenthetical expressions.
 156                 $m = array();
 157                 $q = array();
 158
 159                 if (preg_match_all('/([-+<>~]?)(([' . $lc . ']+)(\*?)|"[^"]*")/',
 160                           $filteredText, $m, PREG_SET_ORDER)) {
 161                         foreach($m as $terms) {
 162                                 $q[] = $terms[1] . $wgContLang->stripForSearch($terms[2]);
 163
 164                                 if (!empty($terms[3])) {
 165                                         $regexp = preg_quote( $terms[3], '/' );
 166                                         if ($terms[4])
 167                                                 $regexp .= "[0-9A-Za-z_]+";
 168                                 } else {
 169                                         $regexp = preg_quote(str_replace('"', '', $terms[2]), '/');
 170                                 }
 171                                 $this->searchTerms[] = $regexp;
 172                         }
 173                 }
 174
 175                 $searchon = $this->db->strencode(join(',', $q));
 176                 $field = $this->getIndexField($fulltext);
 177
 178                 // requires Net Search Extender or equivalent
 179                 //return " CONTAINS($field, '$searchon') > 0 ";
 180
 181                 return " lcase($field) LIKE lcase('%$searchon%')";
 182         }
 183
 184         /**
 185          * Create or update the search index record for the given page.
 186          * Title and text should be pre-processed.
 187          *
 188          * @param int $id
 189          * @param string $title
 190          * @param string $text
 191          */
 192         function update($id, $title, $text) {
 193                 $dbw = wfGetDB(DB_MASTER);
 194                 $dbw->replace('searchindex',
 195                         array('si_page'),
 196                         array(
 197                                 'si_page' => $id,
 198                                 'si_title' => $title,
 199                                 'si_text' => $text
 200                         ), 'SearchIBM_DB2::update' );
 201                 // ?
 202                 //$dbw->query("CALL ctx_ddl.sync_index('si_text_idx')");
 203                 //$dbw->query("CALL ctx_ddl.sync_index('si_title_idx')");
 204         }
 205
 206         /**
 207          * Update a search index record's title only.
 208          * Title should be pre-processed.
 209          *
 210          * @param int $id
 211          * @param string $title
 212          */
 213         function updateTitle($id, $title) {
 214                 $dbw = wfGetDB(DB_MASTER);
 215
 216                 $dbw->update('searchindex',
 217                         array('si_title' => $title),
 218                         array('si_page'  => $id),
 219                         'SearchIBM_DB2::updateTitle',
 220                         array());
 221         }
 222 }
 223
 224 /**
 225  * @ingroup Search
 226  */
 227 class IBM_DB2SearchResultSet extends SearchResultSet {
 228         function __construct($resultSet, $terms) {
 229                 $this->mResultSet = $resultSet;
 230                 $this->mTerms = $terms;
 231         }
 232
 233         function termMatches() {
 234                 return $this->mTerms;
 235         }
 236
 237         function numRows() {
 238                 return $this->mResultSet->numRows();
 239         }
 240
 241         function next() {
 242                 $row = $this->mResultSet->fetchObject();
 243                 if ($row === false)
 244                         return false;
 245                 return new SearchResult($row);
 246         }
 247 }