includes/search/SearchSqlite.php

   1 <?php
   2 /**
   3  * SQLite search backend, based upon SearchMysql
   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  * @file
  21  * @ingroup Search
  22  */
  23
  24 /**
  25  * Search engine hook for SQLite
  26  * @ingroup Search
  27  */
  28 class SearchSqlite extends SearchDatabase {
  29         /**
  30          * Whether fulltext search is supported by current schema
  31          * @return bool
  32          */
  33         function fulltextSearchSupported() {
  34                 return $this->db->checkForEnabledSearch();
  35         }
  36
  37         /**
  38          * Parse the user's query and transform it into an SQL fragment which will
  39          * become part of a WHERE clause
  40          *
  41          * @return string
  42          */
  43         function parseQuery( $filteredText, $fulltext ) {
  44                 global $wgContLang;
  45                 $lc = $this->legalSearchChars(); // Minus format chars
  46                 $searchon = '';
  47                 $this->searchTerms = array();
  48
  49                 $m = array();
  50                 if ( preg_match_all( '/([-+<>~]?)(([' . $lc . ']+)(\*?)|"[^"]*")/',
  51                                 $filteredText, $m, PREG_SET_ORDER ) ) {
  52                         foreach ( $m as $bits ) {
  53                                 wfSuppressWarnings();
  54                                 list( /* all */, $modifier, $term, $nonQuoted, $wildcard ) = $bits;
  55                                 wfRestoreWarnings();
  56
  57                                 if ( $nonQuoted != '' ) {
  58                                         $term = $nonQuoted;
  59                                         $quote = '';
  60                                 } else {
  61                                         $term = str_replace( '"', '', $term );
  62                                         $quote = '"';
  63                                 }
  64
  65                                 if ( $searchon !== '' ) {
  66                                         $searchon .= ' ';
  67                                 }
  68
  69                                 // Some languages such as Serbian store the input form in the search index,
  70                                 // so we may need to search for matches in multiple writing system variants.
  71                                 $convertedVariants = $wgContLang->autoConvertToAllVariants( $term );
  72                                 if ( is_array( $convertedVariants ) ) {
  73                                         $variants = array_unique( array_values( $convertedVariants ) );
  74                                 } else {
  75                                         $variants = array( $term );
  76                                 }
  77
  78                                 // The low-level search index does some processing on input to work
  79                                 // around problems with minimum lengths and encoding in MySQL's
  80                                 // fulltext engine.
  81                                 // For Chinese this also inserts spaces between adjacent Han characters.
  82                                 $strippedVariants = array_map(
  83                                         array( $wgContLang, 'normalizeForSearch' ),
  84                                         $variants );
  85
  86                                 // Some languages such as Chinese force all variants to a canonical
  87                                 // form when stripping to the low-level search index, so to be sure
  88                                 // let's check our variants list for unique items after stripping.
  89                                 $strippedVariants = array_unique( $strippedVariants );
  90
  91                                 $searchon .= $modifier;
  92                                 if ( count( $strippedVariants ) > 1 ) {
  93                                         $searchon .= '(';
  94                                 }
  95                                 foreach ( $strippedVariants as $stripped ) {
  96                                         if ( $nonQuoted && strpos( $stripped, ' ' ) !== false ) {
  97                                                 // Hack for Chinese: we need to toss in quotes for
  98                                                 // multiple-character phrases since normalizeForSearch()
  99                                                 // added spaces between them to make word breaks.
 100                                                 $stripped = '"' . trim( $stripped ) . '"';
 101                                         }
 102                                         $searchon .= "$quote$stripped$quote$wildcard ";
 103                                 }
 104                                 if ( count( $strippedVariants ) > 1 ) {
 105                                         $searchon .= ')';
 106                                 }
 107
 108                                 // Match individual terms or quoted phrase in result highlighting...
 109                                 // Note that variants will be introduced in a later stage for highlighting!
 110                                 $regexp = $this->regexTerm( $term, $wildcard );
 111                                 $this->searchTerms[] = $regexp;
 112                         }
 113
 114                 } else {
 115                         wfDebug( __METHOD__ . ": Can't understand search query '{$filteredText}'\n" );
 116                 }
 117
 118                 $searchon = $this->db->addQuotes( $searchon );
 119                 $field = $this->getIndexField( $fulltext );
 120                 return " $field MATCH $searchon ";
 121         }
 122
 123         function regexTerm( $string, $wildcard ) {
 124                 global $wgContLang;
 125
 126                 $regex = preg_quote( $string, '/' );
 127                 if ( $wgContLang->hasWordBreaks() ) {
 128                         if ( $wildcard ) {
 129                                 // Don't cut off the final bit!
 130                                 $regex = "\b$regex";
 131                         } else {
 132                                 $regex = "\b$regex\b";
 133                         }
 134                 } else {
 135                         // For Chinese, words may legitimately abut other words in the text literal.
 136                         // Don't add \b boundary checks... note this could cause false positives
 137                         // for latin chars.
 138                 }
 139                 return $regex;
 140         }
 141
 142         public static function legalSearchChars() {
 143                 return "\"*" . parent::legalSearchChars();
 144         }
 145
 146         /**
 147          * Perform a full text search query and return a result set.
 148          *
 149          * @param string $term Raw search term
 150          * @return SqlSearchResultSet
 151          */
 152         function searchText( $term ) {
 153                 return $this->searchInternal( $term, true );
 154         }
 155
 156         /**
 157          * Perform a title-only search query and return a result set.
 158          *
 159          * @param string $term Raw search term
 160          * @return SqlSearchResultSet
 161          */
 162         function searchTitle( $term ) {
 163                 return $this->searchInternal( $term, false );
 164         }
 165
 166         protected function searchInternal( $term, $fulltext ) {
 167                 global $wgContLang;
 168
 169                 if ( !$this->fulltextSearchSupported() ) {
 170                         return null;
 171                 }
 172
 173                 $filteredTerm = $this->filter( $wgContLang->lc( $term ) );
 174                 $resultSet = $this->db->query( $this->getQuery( $filteredTerm, $fulltext ) );
 175
 176                 $total = null;
 177                 $totalResult = $this->db->query( $this->getCountQuery( $filteredTerm, $fulltext ) );
 178                 $row = $totalResult->fetchObject();
 179                 if ( $row ) {
 180                         $total = intval( $row->c );
 181                 }
 182                 $totalResult->free();
 183
 184                 return new SqlSearchResultSet( $resultSet, $this->searchTerms, $total );
 185         }
 186
 187         /**
 188          * Return a partial WHERE clause to limit the search to the given namespaces
 189          * @return string
 190          */
 191         function queryNamespaces() {
 192                 if ( is_null( $this->namespaces ) ) {
 193                         return '';  # search all
 194                 }
 195                 if ( !count( $this->namespaces ) ) {
 196                         $namespaces = '0';
 197                 } else {
 198                         $namespaces = $this->db->makeList( $this->namespaces );
 199                 }
 200                 return 'AND page_namespace IN (' . $namespaces . ')';
 201         }
 202
 203         /**
 204          * Returns a query with limit for number of results set.
 205          * @param string $sql
 206          * @return string
 207          */
 208         function limitResult( $sql ) {
 209                 return $this->db->limitResult( $sql, $this->limit, $this->offset );
 210         }
 211
 212         /**
 213          * Construct the full SQL query to do the search.
 214          * The guts shoulds be constructed in queryMain()
 215          * @param string $filteredTerm
 216          * @param bool $fulltext
 217          * @return string
 218          */
 219         function getQuery( $filteredTerm, $fulltext ) {
 220                 return $this->limitResult(
 221                         $this->queryMain( $filteredTerm, $fulltext ) . ' ' .
 222                         $this->queryNamespaces()
 223                 );
 224         }
 225
 226         /**
 227          * Picks which field to index on, depending on what type of query.
 228          * @param bool $fulltext
 229          * @return string
 230          */
 231         function getIndexField( $fulltext ) {
 232                 return $fulltext ? 'si_text' : 'si_title';
 233         }
 234
 235         /**
 236          * Get the base part of the search query.
 237          *
 238          * @param string $filteredTerm
 239          * @param bool $fulltext
 240          * @return string
 241          */
 242         function queryMain( $filteredTerm, $fulltext ) {
 243                 $match = $this->parseQuery( $filteredTerm, $fulltext );
 244                 $page = $this->db->tableName( 'page' );
 245                 $searchindex = $this->db->tableName( 'searchindex' );
 246                 return "SELECT $searchindex.rowid, page_namespace, page_title " .
 247                         "FROM $page,$searchindex " .
 248                         "WHERE page_id=$searchindex.rowid AND $match";
 249         }
 250
 251         function getCountQuery( $filteredTerm, $fulltext ) {
 252                 $match = $this->parseQuery( $filteredTerm, $fulltext );
 253                 $page = $this->db->tableName( 'page' );
 254                 $searchindex = $this->db->tableName( 'searchindex' );
 255                 return "SELECT COUNT(*) AS c " .
 256                         "FROM $page,$searchindex " .
 257                         "WHERE page_id=$searchindex.rowid AND $match " .
 258                         $this->queryNamespaces();
 259         }
 260
 261         /**
 262          * Create or update the search index record for the given page.
 263          * Title and text should be pre-processed.
 264          *
 265          * @param int $id
 266          * @param string $title
 267          * @param string $text
 268          */
 269         function update( $id, $title, $text ) {
 270                 if ( !$this->fulltextSearchSupported() ) {
 271                         return;
 272                 }
 273                 // @todo find a method to do it in a single request,
 274                 // couldn't do it so far due to typelessness of FTS3 tables.
 275                 $dbw = wfGetDB( DB_MASTER );
 276
 277                 $dbw->delete( 'searchindex', array( 'rowid' => $id ), __METHOD__ );
 278
 279                 $dbw->insert( 'searchindex',
 280                         array(
 281                                 'rowid' => $id,
 282                                 'si_title' => $title,
 283                                 'si_text' => $text
 284                         ), __METHOD__ );
 285         }
 286
 287         /**
 288          * Update a search index record's title only.
 289          * Title should be pre-processed.
 290          *
 291          * @param int $id
 292          * @param string $title
 293          */
 294         function updateTitle( $id, $title ) {
 295                 if ( !$this->fulltextSearchSupported() ) {
 296                         return;
 297                 }
 298                 $dbw = wfGetDB( DB_MASTER );
 299
 300                 $dbw->update( 'searchindex',
 301                         array( 'si_title' => $title ),
 302                         array( 'rowid' => $id ),
 303                         __METHOD__ );
 304         }
 305 }