includes/search/SearchEngine.php

   1 <?php
   2 /**
   3  * Basic search engine
   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  * @defgroup Search Search
  26  */
  27
  28 /**
  29  * Contain a class for special pages
  30  * @ingroup Search
  31  */
  32 class SearchEngine {
  33         var $limit = 10;
  34         var $offset = 0;
  35         var $prefix = '';
  36         var $searchTerms = array();
  37         var $namespaces = array( NS_MAIN );
  38         var $showRedirects = false;
  39
  40         /// Feature values
  41         protected $features = array();
  42
  43         /**
  44          * @var DatabaseBase
  45          */
  46         protected $db;
  47
  48         function __construct( $db = null ) {
  49                 if ( $db ) {
  50                         $this->db = $db;
  51                 } else {
  52                         $this->db = wfGetDB( DB_SLAVE );
  53                 }
  54         }
  55
  56         /**
  57          * Perform a full text search query and return a result set.
  58          * If title searches are not supported or disabled, return null.
  59          * STUB
  60          *
  61          * @param string $term raw search term
  62          * @return SearchResultSet|Status|null
  63          */
  64         function searchText( $term ) {
  65                 return null;
  66         }
  67
  68         /**
  69          * Perform a title-only search query and return a result set.
  70          * If title searches are not supported or disabled, return null.
  71          * STUB
  72          *
  73          * @param string $term raw search term
  74          * @return SearchResultSet|null
  75          */
  76         function searchTitle( $term ) {
  77                 return null;
  78         }
  79
  80         /**
  81          * If this search backend can list/unlist redirects
  82          * @deprecated since 1.18 Call supports( 'list-redirects' );
  83          * @return bool
  84          */
  85         function acceptListRedirects() {
  86                 wfDeprecated( __METHOD__, '1.18' );
  87                 return $this->supports( 'list-redirects' );
  88         }
  89
  90         /**
  91          * @since 1.18
  92          * @param $feature String
  93          * @return Boolean
  94          */
  95         public function supports( $feature ) {
  96                 switch ( $feature ) {
  97                 case 'list-redirects':
  98                         return true;
  99                 case 'title-suffix-filter':
 100                 default:
 101                         return false;
 102                 }
 103         }
 104
 105         /**
 106          * Way to pass custom data for engines
 107          * @since 1.18
 108          * @param $feature String
 109          * @param $data Mixed
 110          * @return bool
 111          */
 112         public function setFeatureData( $feature, $data ) {
 113                 $this->features[$feature] = $data;
 114         }
 115
 116         /**
 117          * When overridden in derived class, performs database-specific conversions
 118          * on text to be used for searching or updating search index.
 119          * Default implementation does nothing (simply returns $string).
 120          *
 121          * @param string $string String to process
 122          * @return string
 123          */
 124         public function normalizeText( $string ) {
 125                 global $wgContLang;
 126
 127                 // Some languages such as Chinese require word segmentation
 128                 return $wgContLang->segmentByWord( $string );
 129         }
 130
 131         /**
 132          * Transform search term in cases when parts of the query came as different GET params (when supported)
 133          * e.g. for prefix queries: search=test&prefix=Main_Page/Archive -> test prefix:Main Page/Archive
 134          */
 135         function transformSearchTerm( $term ) {
 136                 return $term;
 137         }
 138
 139         /**
 140          * If an exact title match can be found, or a very slightly close match,
 141          * return the title. If no match, returns NULL.
 142          *
 143          * @param $searchterm String
 144          * @return Title
 145          */
 146         public static function getNearMatch( $searchterm ) {
 147                 $title = self::getNearMatchInternal( $searchterm );
 148
 149                 wfRunHooks( 'SearchGetNearMatchComplete', array( $searchterm, &$title ) );
 150                 return $title;
 151         }
 152
 153         /**
 154          * Do a near match (see SearchEngine::getNearMatch) and wrap it into a
 155          * SearchResultSet.
 156          *
 157          * @param $searchterm string
 158          * @return SearchResultSet
 159          */
 160         public static function getNearMatchResultSet( $searchterm ) {
 161                 return new SearchNearMatchResultSet( self::getNearMatch( $searchterm ) );
 162         }
 163
 164         /**
 165          * Really find the title match.
 166          * @return null|Title
 167          */
 168         private static function getNearMatchInternal( $searchterm ) {
 169                 global $wgContLang, $wgEnableSearchContributorsByIP;
 170
 171                 $allSearchTerms = array( $searchterm );
 172
 173                 if ( $wgContLang->hasVariants() ) {
 174                         $allSearchTerms = array_merge( $allSearchTerms, $wgContLang->autoConvertToAllVariants( $searchterm ) );
 175                 }
 176
 177                 $titleResult = null;
 178                 if ( !wfRunHooks( 'SearchGetNearMatchBefore', array( $allSearchTerms, &$titleResult ) ) ) {
 179                         return $titleResult;
 180                 }
 181
 182                 foreach ( $allSearchTerms as $term ) {
 183
 184                         # Exact match? No need to look further.
 185                         $title = Title::newFromText( $term );
 186                         if ( is_null( $title ) ) {
 187                                 return null;
 188                         }
 189
 190                         # Try files if searching in the Media: namespace
 191                         if ( $title->getNamespace() == NS_MEDIA ) {
 192                                 $title = Title::makeTitle( NS_FILE, $title->getText() );
 193                         }
 194
 195                         if ( $title->isSpecialPage() || $title->isExternal() || $title->exists() ) {
 196                                 return $title;
 197                         }
 198
 199                         # See if it still otherwise has content is some sane sense
 200                         $page = WikiPage::factory( $title );
 201                         if ( $page->hasViewableContent() ) {
 202                                 return $title;
 203                         }
 204
 205                         if ( !wfRunHooks( 'SearchAfterNoDirectMatch', array( $term, &$title ) ) ) {
 206                                 return $title;
 207                         }
 208
 209                         # Now try all lower case (i.e. first letter capitalized)
 210                         $title = Title::newFromText( $wgContLang->lc( $term ) );
 211                         if ( $title && $title->exists() ) {
 212                                 return $title;
 213                         }
 214
 215                         # Now try capitalized string
 216                         $title = Title::newFromText( $wgContLang->ucwords( $term ) );
 217                         if ( $title && $title->exists() ) {
 218                                 return $title;
 219                         }
 220
 221                         # Now try all upper case
 222                         $title = Title::newFromText( $wgContLang->uc( $term ) );
 223                         if ( $title && $title->exists() ) {
 224                                 return $title;
 225                         }
 226
 227                         # Now try Word-Caps-Breaking-At-Word-Breaks, for hyphenated names etc
 228                         $title = Title::newFromText( $wgContLang->ucwordbreaks( $term ) );
 229                         if ( $title && $title->exists() ) {
 230                                 return $title;
 231                         }
 232
 233                         // Give hooks a chance at better match variants
 234                         $title = null;
 235                         if ( !wfRunHooks( 'SearchGetNearMatch', array( $term, &$title ) ) ) {
 236                                 return $title;
 237                         }
 238                 }
 239
 240                 $title = Title::newFromText( $searchterm );
 241
 242                 # Entering an IP address goes to the contributions page
 243                 if ( $wgEnableSearchContributorsByIP ) {
 244                         if ( ( $title->getNamespace() == NS_USER && User::isIP( $title->getText() ) )
 245                                 || User::isIP( trim( $searchterm ) ) ) {
 246                                 return SpecialPage::getTitleFor( 'Contributions', $title->getDBkey() );
 247                         }
 248                 }
 249
 250                 # Entering a user goes to the user page whether it's there or not
 251                 if ( $title->getNamespace() == NS_USER ) {
 252                         return $title;
 253                 }
 254
 255                 # Go to images that exist even if there's no local page.
 256                 # There may have been a funny upload, or it may be on a shared
 257                 # file repository such as Wikimedia Commons.
 258                 if ( $title->getNamespace() == NS_FILE ) {
 259                         $image = wfFindFile( $title );
 260                         if ( $image ) {
 261                                 return $title;
 262                         }
 263                 }
 264
 265                 # MediaWiki namespace? Page may be "implied" if not customized.
 266                 # Just return it, with caps forced as the message system likes it.
 267                 if ( $title->getNamespace() == NS_MEDIAWIKI ) {
 268                         return Title::makeTitle( NS_MEDIAWIKI, $wgContLang->ucfirst( $title->getText() ) );
 269                 }
 270
 271                 # Quoted term? Try without the quotes...
 272                 $matches = array();
 273                 if ( preg_match( '/^"([^"]+)"$/', $searchterm, $matches ) ) {
 274                         return SearchEngine::getNearMatch( $matches[1] );
 275                 }
 276
 277                 return null;
 278         }
 279
 280         public static function legalSearchChars() {
 281                 return "A-Za-z_'.0-9\\x80-\\xFF\\-";
 282         }
 283
 284         /**
 285          * Set the maximum number of results to return
 286          * and how many to skip before returning the first.
 287          *
 288          * @param $limit Integer
 289          * @param $offset Integer
 290          */
 291         function setLimitOffset( $limit, $offset = 0 ) {
 292                 $this->limit = intval( $limit );
 293                 $this->offset = intval( $offset );
 294         }
 295
 296         /**
 297          * Set which namespaces the search should include.
 298          * Give an array of namespace index numbers.
 299          *
 300          * @param $namespaces Array
 301          */
 302         function setNamespaces( $namespaces ) {
 303                 $this->namespaces = $namespaces;
 304         }
 305
 306         /**
 307          * Parse some common prefixes: all (search everything)
 308          * or namespace names
 309          *
 310          * @param $query String
 311          * @return string
 312          */
 313         function replacePrefixes( $query ) {
 314                 global $wgContLang;
 315
 316                 $parsed = $query;
 317                 if ( strpos( $query, ':' ) === false ) { // nothing to do
 318                         wfRunHooks( 'SearchEngineReplacePrefixesComplete', array( $this, $query, &$parsed ) );
 319                         return $parsed;
 320                 }
 321
 322                 $allkeyword = wfMessage( 'searchall' )->inContentLanguage()->text() . ":";
 323                 if ( strncmp( $query, $allkeyword, strlen( $allkeyword ) ) == 0 ) {
 324                         $this->namespaces = null;
 325                         $parsed = substr( $query, strlen( $allkeyword ) );
 326                 } elseif ( strpos( $query, ':' ) !== false ) {
 327                         $prefix = substr( $query, 0, strpos( $query, ':' ) );
 328                         $index = $wgContLang->getNsIndex( $prefix );
 329                         if ( $index !== false ) {
 330                                 $this->namespaces = array( $index );
 331                                 $parsed = substr( $query, strlen( $prefix ) + 1 );
 332                         }
 333                 }
 334                 if ( trim( $parsed ) == '' ) {
 335                         $parsed = $query; // prefix was the whole query
 336                 }
 337
 338                 wfRunHooks( 'SearchEngineReplacePrefixesComplete', array( $this, $query, &$parsed ) );
 339
 340                 return $parsed;
 341         }
 342
 343         /**
 344          * Make a list of searchable namespaces and their canonical names.
 345          * @return Array
 346          */
 347         public static function searchableNamespaces() {
 348                 global $wgContLang;
 349                 $arr = array();
 350                 foreach ( $wgContLang->getNamespaces() as $ns => $name ) {
 351                         if ( $ns >= NS_MAIN ) {
 352                                 $arr[$ns] = $name;
 353                         }
 354                 }
 355
 356                 wfRunHooks( 'SearchableNamespaces', array( &$arr ) );
 357                 return $arr;
 358         }
 359
 360         /**
 361          * Extract default namespaces to search from the given user's
 362          * settings, returning a list of index numbers.
 363          *
 364          * @param $user User
 365          * @return Array
 366          */
 367         public static function userNamespaces( $user ) {
 368                 global $wgSearchEverythingOnlyLoggedIn;
 369
 370                 $searchableNamespaces = SearchEngine::searchableNamespaces();
 371
 372                 // get search everything preference, that can be set to be read for logged-in users
 373                 // it overrides other options
 374                 if ( !$wgSearchEverythingOnlyLoggedIn || $user->isLoggedIn() ) {
 375                         if ( $user->getOption( 'searcheverything' ) ) {
 376                                 return array_keys( $searchableNamespaces );
 377                         }
 378                 }
 379
 380                 $arr = array();
 381                 foreach ( $searchableNamespaces as $ns => $name ) {
 382                         if ( $user->getOption( 'searchNs' . $ns ) ) {
 383                                 $arr[] = $ns;
 384                         }
 385                 }
 386
 387                 return $arr;
 388         }
 389
 390         /**
 391          * Find snippet highlight settings for all users
 392          *
 393          * @return Array contextlines, contextchars
 394          */
 395         public static function userHighlightPrefs() {
 396                 $contextlines = 2; // Hardcode this. Old defaults sucked. :)
 397                 $contextchars = 75; // same as above.... :P
 398                 return array( $contextlines, $contextchars );
 399         }
 400
 401         /**
 402          * An array of namespaces indexes to be searched by default
 403          *
 404          * @return Array
 405          */
 406         public static function defaultNamespaces() {
 407                 global $wgNamespacesToBeSearchedDefault;
 408
 409                 return array_keys( $wgNamespacesToBeSearchedDefault, true );
 410         }
 411
 412         /**
 413          * Get a list of namespace names useful for showing in tooltips
 414          * and preferences
 415          *
 416          * @param $namespaces Array
 417          * @return array
 418          */
 419         public static function namespacesAsText( $namespaces ) {
 420                 global $wgContLang;
 421
 422                 $formatted = array_map( array( $wgContLang, 'getFormattedNsText' ), $namespaces );
 423                 foreach ( $formatted as $key => $ns ) {
 424                         if ( empty( $ns ) ) {
 425                                 $formatted[$key] = wfMessage( 'blanknamespace' )->text();
 426                         }
 427                 }
 428                 return $formatted;
 429         }
 430
 431         /**
 432          * Return the help namespaces to be shown on Special:Search
 433          *
 434          * @return Array
 435          */
 436         public static function helpNamespaces() {
 437                 global $wgNamespacesToBeSearchedHelp;
 438
 439                 return array_keys( $wgNamespacesToBeSearchedHelp, true );
 440         }
 441
 442         /**
 443          * Return a 'cleaned up' search string
 444          *
 445          * @param $text String
 446          * @return String
 447          */
 448         function filter( $text ) {
 449                 $lc = $this->legalSearchChars();
 450                 return trim( preg_replace( "/[^{$lc}]/", " ", $text ) );
 451         }
 452         /**
 453          * Load up the appropriate search engine class for the currently
 454          * active database backend, and return a configured instance.
 455          *
 456          * @param String $type Type of search backend, if not the default
 457          * @return SearchEngine
 458          */
 459         public static function create( $type = null ) {
 460                 global $wgSearchType;
 461                 $dbr = null;
 462
 463                 $alternatives = self::getSearchTypes();
 464                 $type = $type !== null ? $type : $wgSearchType;
 465                 if ( $type && in_array( $type, $alternatives ) ) {
 466                         $class = $type;
 467                 } else {
 468                         $dbr = wfGetDB( DB_SLAVE );
 469                         $class = $dbr->getSearchEngine();
 470                 }
 471                 $search = new $class( $dbr );
 472                 $search->setLimitOffset( 0, 0 );
 473                 return $search;
 474         }
 475
 476         /**
 477          * Return the search engines we support. If only $wgSearchType
 478          * is set, it'll be an array of just that one item.
 479          *
 480          * @return array
 481          */
 482         public static function getSearchTypes() {
 483                 global $wgSearchType, $wgSearchTypeAlternatives;
 484                 static $alternatives = null;
 485                 if ( $alternatives === null ) {
 486                         $alternatives = $wgSearchTypeAlternatives ?: array();
 487                         array_unshift( $alternatives, $wgSearchType );
 488                 }
 489                 return $alternatives;
 490         }
 491
 492         /**
 493          * Create or update the search index record for the given page.
 494          * Title and text should be pre-processed.
 495          * STUB
 496          *
 497          * @param $id Integer
 498          * @param $title String
 499          * @param $text String
 500          */
 501         function update( $id, $title, $text ) {
 502                 // no-op
 503         }
 504
 505         /**
 506          * Update a search index record's title only.
 507          * Title should be pre-processed.
 508          * STUB
 509          *
 510          * @param $id Integer
 511          * @param $title String
 512          */
 513         function updateTitle( $id, $title ) {
 514                 // no-op
 515         }
 516
 517         /**
 518          * Delete an indexed page
 519          * Title should be pre-processed.
 520          * STUB
 521          *
 522          * @param Integer $id Page id that was deleted
 523          * @param String $title Title of page that was deleted
 524          */
 525         function delete( $id, $title ) {
 526                 // no-op
 527         }
 528
 529         /**
 530          * Get OpenSearch suggestion template
 531          *
 532          * @return String
 533          */
 534         public static function getOpenSearchTemplate() {
 535                 global $wgOpenSearchTemplate, $wgCanonicalServer;
 536                 if ( $wgOpenSearchTemplate ) {
 537                         return $wgOpenSearchTemplate;
 538                 } else {
 539                         $ns = implode( '|', SearchEngine::defaultNamespaces() );
 540                         if ( !$ns ) {
 541                                 $ns = "0";
 542                         }
 543                         return $wgCanonicalServer . wfScript( 'api' ) . '?action=opensearch&search={searchTerms}&namespace=' . $ns;
 544                 }
 545         }
 546
 547         /**
 548          * Get the raw text for updating the index from a content object
 549          * Nicer search backends could possibly do something cooler than
 550          * just returning raw text
 551          *
 552          * @todo This isn't ideal, we'd really like to have content-specific handling here
 553          * @param Title $t Title we're indexing
 554          * @param Content $c Content of the page to index
 555          * @return string
 556          */
 557         public function getTextFromContent( Title $t, Content $c = null ) {
 558                 return $c ? $c->getTextForSearchIndex() : '';
 559         }
 560 }
 561
 562 /**
 563  * @ingroup Search
 564  */
 565 class SearchResultSet {
 566         /**
 567          * Fetch an array of regular expression fragments for matching
 568          * the search terms as parsed by this engine in a text extract.
 569          * STUB
 570          *
 571          * @return Array
 572          */
 573         function termMatches() {
 574                 return array();
 575         }
 576
 577         function numRows() {
 578                 return 0;
 579         }
 580
 581         /**
 582          * Return true if results are included in this result set.
 583          * STUB
 584          *
 585          * @return Boolean
 586          */
 587         function hasResults() {
 588                 return false;
 589         }
 590
 591         /**
 592          * Some search modes return a total hit count for the query
 593          * in the entire article database. This may include pages
 594          * in namespaces that would not be matched on the given
 595          * settings.
 596          *
 597          * Return null if no total hits number is supported.
 598          *
 599          * @return Integer
 600          */
 601         function getTotalHits() {
 602                 return null;
 603         }
 604
 605         /**
 606          * Some search modes return a suggested alternate term if there are
 607          * no exact hits. Returns true if there is one on this set.
 608          *
 609          * @return Boolean
 610          */
 611         function hasSuggestion() {
 612                 return false;
 613         }
 614
 615         /**
 616          * @return String: suggested query, null if none
 617          */
 618         function getSuggestionQuery() {
 619                 return null;
 620         }
 621
 622         /**
 623          * @return String: HTML highlighted suggested query, '' if none
 624          */
 625         function getSuggestionSnippet() {
 626                 return '';
 627         }
 628
 629         /**
 630          * Return information about how and from where the results were fetched,
 631          * should be useful for diagnostics and debugging
 632          *
 633          * @return String
 634          */
 635         function getInfo() {
 636                 return null;
 637         }
 638
 639         /**
 640          * Return a result set of hits on other (multiple) wikis associated with this one
 641          *
 642          * @return SearchResultSet
 643          */
 644         function getInterwikiResults() {
 645                 return null;
 646         }
 647
 648         /**
 649          * Check if there are results on other wikis
 650          *
 651          * @return Boolean
 652          */
 653         function hasInterwikiResults() {
 654                 return $this->getInterwikiResults() != null;
 655         }
 656
 657         /**
 658          * Fetches next search result, or false.
 659          * STUB
 660          *
 661          * @return SearchResult
 662          */
 663         function next() {
 664                 return false;
 665         }
 666
 667         /**
 668          * Frees the result set, if applicable.
 669          */
 670         function free() {
 671                 // ...
 672         }
 673 }
 674
 675 /**
 676  * This class is used for different SQL-based search engines shipped with MediaWiki
 677  */
 678 class SqlSearchResultSet extends SearchResultSet {
 679
 680         protected $mResultSet;
 681
 682         function __construct( $resultSet, $terms ) {
 683                 $this->mResultSet = $resultSet;
 684                 $this->mTerms = $terms;
 685         }
 686
 687         function termMatches() {
 688                 return $this->mTerms;
 689         }
 690
 691         function numRows() {
 692                 if ( $this->mResultSet === false ) {
 693                         return false;
 694                 }
 695
 696                 return $this->mResultSet->numRows();
 697         }
 698
 699         function next() {
 700                 if ( $this->mResultSet === false ) {
 701                         return false;
 702                 }
 703
 704                 $row = $this->mResultSet->fetchObject();
 705                 if ( $row === false ) {
 706                         return false;
 707                 }
 708
 709                 return SearchResult::newFromRow( $row );
 710         }
 711
 712         function free() {
 713                 if ( $this->mResultSet === false ) {
 714                         return false;
 715                 }
 716
 717                 $this->mResultSet->free();
 718         }
 719 }
 720
 721 /**
 722  * @ingroup Search
 723  */
 724 class SearchResultTooMany {
 725         # # Some search engines may bail out if too many matches are found
 726 }
 727
 728 /**
 729  * @todo FIXME: This class is horribly factored. It would probably be better to
 730  * have a useful base class to which you pass some standard information, then
 731  * let the fancy self-highlighters extend that.
 732  * @ingroup Search
 733  */
 734 class SearchResult {
 735
 736         /**
 737          * @var Revision
 738          */
 739         var $mRevision = null;
 740         var $mImage = null;
 741
 742         /**
 743          * @var Title
 744          */
 745         var $mTitle;
 746
 747         /**
 748          * @var String
 749          */
 750         var $mText;
 751
 752         /**
 753          * Return a new SearchResult and initializes it with a title.
 754          *
 755          * @param $title Title
 756          * @return SearchResult
 757          */
 758         public static function newFromTitle( $title ) {
 759                 $result = new self();
 760                 $result->initFromTitle( $title );
 761                 return $result;
 762         }
 763         /**
 764          * Return a new SearchResult and initializes it with a row.
 765          *
 766          * @param $row object
 767          * @return SearchResult
 768          */
 769         public static function newFromRow( $row ) {
 770                 $result = new self();
 771                 $result->initFromRow( $row );
 772                 return $result;
 773         }
 774
 775         public function __construct( $row = null ) {
 776                 if ( !is_null( $row ) ) {
 777                         // Backwards compatibility with pre-1.17 callers
 778                         $this->initFromRow( $row );
 779                 }
 780         }
 781
 782         /**
 783          * Initialize from a database row. Makes a Title and passes that to
 784          * initFromTitle.
 785          *
 786          * @param $row object
 787          */
 788         protected function initFromRow( $row ) {
 789                 $this->initFromTitle( Title::makeTitle( $row->page_namespace, $row->page_title ) );
 790         }
 791
 792         /**
 793          * Initialize from a Title and if possible initializes a corresponding
 794          * Revision and File.
 795          *
 796          * @param $title Title
 797          */
 798         protected function initFromTitle( $title ) {
 799                 $this->mTitle = $title;
 800                 if ( !is_null( $this->mTitle ) ) {
 801                         $id = false;
 802                         wfRunHooks( 'SearchResultInitFromTitle', array( $title, &$id ) );
 803                         $this->mRevision = Revision::newFromTitle(
 804                                 $this->mTitle, $id, Revision::READ_NORMAL );
 805                         if ( $this->mTitle->getNamespace() === NS_FILE ) {
 806                                 $this->mImage = wfFindFile( $this->mTitle );
 807                         }
 808                 }
 809         }
 810
 811         /**
 812          * Check if this is result points to an invalid title
 813          *
 814          * @return Boolean
 815          */
 816         function isBrokenTitle() {
 817                 if ( is_null( $this->mTitle ) ) {
 818                         return true;
 819                 }
 820                 return false;
 821         }
 822
 823         /**
 824          * Check if target page is missing, happens when index is out of date
 825          *
 826          * @return Boolean
 827          */
 828         function isMissingRevision() {
 829                 return !$this->mRevision && !$this->mImage;
 830         }
 831
 832         /**
 833          * @return Title
 834          */
 835         function getTitle() {
 836                 return $this->mTitle;
 837         }
 838
 839         /**
 840          * @return float|null if not supported
 841          */
 842         function getScore() {
 843                 return null;
 844         }
 845
 846         /**
 847          * Lazy initialization of article text from DB
 848          */
 849         protected function initText() {
 850                 if ( !isset( $this->mText ) ) {
 851                         if ( $this->mRevision != null ) {
 852                                 $this->mText = SearchEngine::create()
 853                                         ->getTextFromContent( $this->mTitle, $this->mRevision->getContent() );
 854                         } else { // TODO: can we fetch raw wikitext for commons images?
 855                                 $this->mText = '';
 856                         }
 857                 }
 858         }
 859
 860         /**
 861          * @param array $terms terms to highlight
 862          * @return String: highlighted text snippet, null (and not '') if not supported
 863          */
 864         function getTextSnippet( $terms ) {
 865                 global $wgUser, $wgAdvancedSearchHighlighting;
 866                 $this->initText();
 867
 868                 // TODO: make highliter take a content object. Make ContentHandler a factory for SearchHighliter.
 869                 list( $contextlines, $contextchars ) = SearchEngine::userHighlightPrefs( $wgUser );
 870                 $h = new SearchHighlighter();
 871                 if ( $wgAdvancedSearchHighlighting ) {
 872                         return $h->highlightText( $this->mText, $terms, $contextlines, $contextchars );
 873                 } else {
 874                         return $h->highlightSimple( $this->mText, $terms, $contextlines, $contextchars );
 875                 }
 876         }
 877
 878         /**
 879          * @param array $terms terms to highlight
 880          * @return String: highlighted title, '' if not supported
 881          */
 882         function getTitleSnippet( $terms ) {
 883                 return '';
 884         }
 885
 886         /**
 887          * @param array $terms terms to highlight
 888          * @return String: highlighted redirect name (redirect to this page), '' if none or not supported
 889          */
 890         function getRedirectSnippet( $terms ) {
 891                 return '';
 892         }
 893
 894         /**
 895          * @return Title object for the redirect to this page, null if none or not supported
 896          */
 897         function getRedirectTitle() {
 898                 return null;
 899         }
 900
 901         /**
 902          * @return string highlighted relevant section name, null if none or not supported
 903          */
 904         function getSectionSnippet() {
 905                 return '';
 906         }
 907
 908         /**
 909          * @return Title object (pagename+fragment) for the section, null if none or not supported
 910          */
 911         function getSectionTitle() {
 912                 return null;
 913         }
 914
 915         /**
 916          * @return String: timestamp
 917          */
 918         function getTimestamp() {
 919                 if ( $this->mRevision ) {
 920                         return $this->mRevision->getTimestamp();
 921                 } elseif ( $this->mImage ) {
 922                         return $this->mImage->getTimestamp();
 923                 }
 924                 return '';
 925         }
 926
 927         /**
 928          * @return Integer: number of words
 929          */
 930         function getWordCount() {
 931                 $this->initText();
 932                 return str_word_count( $this->mText );
 933         }
 934
 935         /**
 936          * @return Integer: size in bytes
 937          */
 938         function getByteSize() {
 939                 $this->initText();
 940                 return strlen( $this->mText );
 941         }
 942
 943         /**
 944          * @return Boolean if hit has related articles
 945          */
 946         function hasRelated() {
 947                 return false;
 948         }
 949
 950         /**
 951          * @return String: interwiki prefix of the title (return iw even if title is broken)
 952          */
 953         function getInterwikiPrefix() {
 954                 return '';
 955         }
 956 }
 957 /**
 958  * A SearchResultSet wrapper for SearchEngine::getNearMatch
 959  */
 960 class SearchNearMatchResultSet extends SearchResultSet {
 961         private $fetched = false;
 962         /**
 963          * @param $match mixed Title if matched, else null
 964          */
 965         public function __construct( $match ) {
 966                 $this->result = $match;
 967         }
 968         public function hasResult() {
 969                 return (bool)$this->result;
 970         }
 971         public function numRows() {
 972                 return $this->hasResults() ? 1 : 0;
 973         }
 974         public function next() {
 975                 if ( $this->fetched || !$this->result ) {
 976                         return false;
 977                 }
 978                 $this->fetched = true;
 979                 return SearchResult::newFromTitle( $this->result );
 980         }
 981 }
 982
 983 /**
 984  * Highlight bits of wikitext
 985  *
 986  * @ingroup Search
 987  */
 988 class SearchHighlighter {
 989         var $mCleanWikitext = true;
 990
 991         function __construct( $cleanupWikitext = true ) {
 992                 $this->mCleanWikitext = $cleanupWikitext;
 993         }
 994
 995         /**
 996          * Default implementation of wikitext highlighting
 997          *
 998          * @param $text String
 999          * @param array $terms terms to highlight (unescaped)
1000          * @param $contextlines Integer
1001          * @param $contextchars Integer
1002          * @return String
1003          */
1004         public function highlightText( $text, $terms, $contextlines, $contextchars ) {
1005                 global $wgContLang;
1006                 global $wgSearchHighlightBoundaries;
1007                 $fname = __METHOD__;
1008
1009                 if ( $text == '' ) {
1010                         return '';
1011                 }
1012
1013                 // spli text into text + templates/links/tables
1014                 $spat = "/(\\{\\{)|(\\[\\[[^\\]:]+:)|(\n\\{\\|)";
1015                 // first capture group is for detecting nested templates/links/tables/references
1016                 $endPatterns = array(
1017                         1 => '/(\{\{)|(\}\})/', // template
1018                         2 => '/(\[\[)|(\]\])/', // image
1019                         3 => "/(\n\\{\\|)|(\n\\|\\})/" ); // table
1020
1021                 // @todo FIXME: This should prolly be a hook or something
1022                 if ( function_exists( 'wfCite' ) ) {
1023                         $spat .= '|(<ref>)'; // references via cite extension
1024                         $endPatterns[4] = '/(<ref>)|(<\/ref>)/';
1025                 }
1026                 $spat .= '/';
1027                 $textExt = array(); // text extracts
1028                 $otherExt = array(); // other extracts
1029                 wfProfileIn( "$fname-split" );
1030                 $start = 0;
1031                 $textLen = strlen( $text );
1032                 $count = 0; // sequence number to maintain ordering
1033                 while ( $start < $textLen ) {
1034                         // find start of template/image/table
1035                         if ( preg_match( $spat, $text, $matches, PREG_OFFSET_CAPTURE, $start ) ) {
1036                                 $epat = '';
1037                                 foreach ( $matches as $key => $val ) {
1038                                         if ( $key > 0 && $val[1] != - 1 ) {
1039                                                 if ( $key == 2 ) {
1040                                                         // see if this is an image link
1041                                                         $ns = substr( $val[0], 2, - 1 );
1042                                                         if ( $wgContLang->getNsIndex( $ns ) != NS_FILE ) {
1043                                                                 break;
1044                                                         }
1045
1046                                                 }
1047                                                 $epat = $endPatterns[$key];
1048                                                 $this->splitAndAdd( $textExt, $count, substr( $text, $start, $val[1] - $start ) );
1049                                                 $start = $val[1];
1050                                                 break;
1051                                         }
1052                                 }
1053                                 if ( $epat ) {
1054                                         // find end (and detect any nested elements)
1055                                         $level = 0;
1056                                         $offset = $start + 1;
1057                                         $found = false;
1058                                         while ( preg_match( $epat, $text, $endMatches, PREG_OFFSET_CAPTURE, $offset ) ) {
1059                                                 if ( array_key_exists( 2, $endMatches ) ) {
1060                                                         // found end
1061                                                         if ( $level == 0 ) {
1062                                                                 $len = strlen( $endMatches[2][0] );
1063                                                                 $off = $endMatches[2][1];
1064                                                                 $this->splitAndAdd( $otherExt, $count,
1065                                                                         substr( $text, $start, $off + $len - $start ) );
1066                                                                 $start = $off + $len;
1067                                                                 $found = true;
1068                                                                 break;
1069                                                         } else {
1070                                                                 // end of nested element
1071                                                                 $level -= 1;
1072                                                         }
1073                                                 } else {
1074                                                         // nested
1075                                                         $level += 1;
1076                                                 }
1077                                                 $offset = $endMatches[0][1] + strlen( $endMatches[0][0] );
1078                                         }
1079                                         if ( ! $found ) {
1080                                                 // couldn't find appropriate closing tag, skip
1081                                                 $this->splitAndAdd( $textExt, $count, substr( $text, $start, strlen( $matches[0][0] ) ) );
1082                                                 $start += strlen( $matches[0][0] );
1083                                         }
1084                                         continue;
1085                                 }
1086                         }
1087                         // else: add as text extract
1088                         $this->splitAndAdd( $textExt, $count, substr( $text, $start ) );
1089                         break;
1090                 }
1091
1092                 $all = $textExt + $otherExt; // these have disjunct key sets
1093
1094                 wfProfileOut( "$fname-split" );
1095
1096                 // prepare regexps
1097                 foreach ( $terms as $index => $term ) {
1098                         // manually do upper/lowercase stuff for utf-8 since PHP won't do it
1099                         if ( preg_match( '/[\x80-\xff]/', $term ) ) {
1100                                 $terms[$index] = preg_replace_callback( '/./us', array( $this, 'caseCallback' ), $terms[$index] );
1101                         } else {
1102                                 $terms[$index] = $term;
1103                         }
1104                 }
1105                 $anyterm = implode( '|', $terms );
1106                 $phrase = implode( "$wgSearchHighlightBoundaries+", $terms );
1107
1108                 // @todo FIXME: A hack to scale contextchars, a correct solution
1109                 // would be to have contextchars actually be char and not byte
1110                 // length, and do proper utf-8 substrings and lengths everywhere,
1111                 // but PHP is making that very hard and unclean to implement :(
1112                 $scale = strlen( $anyterm ) / mb_strlen( $anyterm );
1113                 $contextchars = intval( $contextchars * $scale );
1114
1115                 $patPre = "(^|$wgSearchHighlightBoundaries)";
1116                 $patPost = "($wgSearchHighlightBoundaries|$)";
1117
1118                 $pat1 = "/(" . $phrase . ")/ui";
1119                 $pat2 = "/$patPre(" . $anyterm . ")$patPost/ui";
1120
1121                 wfProfileIn( "$fname-extract" );
1122
1123                 $left = $contextlines;
1124
1125                 $snippets = array();
1126                 $offsets = array();
1127
1128                 // show beginning only if it contains all words
1129                 $first = 0;
1130                 $firstText = '';
1131                 foreach ( $textExt as $index => $line ) {
1132                         if ( strlen( $line ) > 0 && $line[0] != ';' && $line[0] != ':' ) {
1133                                 $firstText = $this->extract( $line, 0, $contextchars * $contextlines );
1134                                 $first = $index;
1135                                 break;
1136                         }
1137                 }
1138                 if ( $firstText ) {
1139                         $succ = true;
1140                         // check if first text contains all terms
1141                         foreach ( $terms as $term ) {
1142                                 if ( ! preg_match( "/$patPre" . $term . "$patPost/ui", $firstText ) ) {
1143                                         $succ = false;
1144                                         break;
1145                                 }
1146                         }
1147                         if ( $succ ) {
1148                                 $snippets[$first] = $firstText;
1149                                 $offsets[$first] = 0;
1150                         }
1151                 }
1152                 if ( ! $snippets ) {
1153                         // match whole query on text
1154                         $this->process( $pat1, $textExt, $left, $contextchars, $snippets, $offsets );
1155                         // match whole query on templates/tables/images
1156                         $this->process( $pat1, $otherExt, $left, $contextchars, $snippets, $offsets );
1157                         // match any words on text
1158                         $this->process( $pat2, $textExt, $left, $contextchars, $snippets, $offsets );
1159                         // match any words on templates/tables/images
1160                         $this->process( $pat2, $otherExt, $left, $contextchars, $snippets, $offsets );
1161
1162                         ksort( $snippets );
1163                 }
1164
1165                 // add extra chars to each snippet to make snippets constant size
1166                 $extended = array();
1167                 if ( count( $snippets ) == 0 ) {
1168                         // couldn't find the target words, just show beginning of article
1169                         if ( array_key_exists( $first, $all ) ) {
1170                                 $targetchars = $contextchars * $contextlines;
1171                                 $snippets[$first] = '';
1172                                 $offsets[$first] = 0;
1173                         }
1174                 } else {
1175                         // if begin of the article contains the whole phrase, show only that !!
1176                         if ( array_key_exists( $first, $snippets ) && preg_match( $pat1, $snippets[$first] )
1177                                 && $offsets[$first] < $contextchars * 2 ) {
1178                                 $snippets = array( $first => $snippets[$first] );
1179                         }
1180
1181                         // calc by how much to extend existing snippets
1182                         $targetchars = intval( ( $contextchars * $contextlines ) / count ( $snippets ) );
1183                 }
1184
1185                 foreach ( $snippets as $index => $line ) {
1186                         $extended[$index] = $line;
1187                         $len = strlen( $line );
1188                         if ( $len < $targetchars - 20 ) {
1189                                 // complete this line
1190                                 if ( $len < strlen( $all[$index] ) ) {
1191                                         $extended[$index] = $this->extract( $all[$index], $offsets[$index], $offsets[$index] + $targetchars, $offsets[$index] );
1192                                         $len = strlen( $extended[$index] );
1193                                 }
1194
1195                                 // add more lines
1196                                 $add = $index + 1;
1197                                 while ( $len < $targetchars - 20
1198                                                 && array_key_exists( $add, $all )
1199                                                 && !array_key_exists( $add, $snippets ) ) {
1200                                         $offsets[$add] = 0;
1201                                         $tt = "\n" . $this->extract( $all[$add], 0, $targetchars - $len, $offsets[$add] );
1202                                         $extended[$add] = $tt;
1203                                         $len += strlen( $tt );
1204                                         $add++;
1205                                 }
1206                         }
1207                 }
1208
1209                 // $snippets = array_map( 'htmlspecialchars', $extended );
1210                 $snippets = $extended;
1211                 $last = - 1;
1212                 $extract = '';
1213                 foreach ( $snippets as $index => $line ) {
1214                         if ( $last == - 1 ) {
1215                                 $extract .= $line; // first line
1216                         } elseif ( $last + 1 == $index && $offsets[$last] + strlen( $snippets[$last] ) >= strlen( $all[$last] ) ) {
1217                                 $extract .= " " . $line; // continous lines
1218                         } else {
1219                                 $extract .= '<b> ... </b>' . $line;
1220                         }
1221
1222                         $last = $index;
1223                 }
1224                 if ( $extract ) {
1225                         $extract .= '<b> ... </b>';
1226                 }
1227
1228                 $processed = array();
1229                 foreach ( $terms as $term ) {
1230                         if ( ! isset( $processed[$term] ) ) {
1231                                 $pat3 = "/$patPre(" . $term . ")$patPost/ui"; // highlight word
1232                                 $extract = preg_replace( $pat3,
1233                                         "\\1<span class='searchmatch'>\\2</span>\\3", $extract );
1234                                 $processed[$term] = true;
1235                         }
1236                 }
1237
1238                 wfProfileOut( "$fname-extract" );
1239
1240                 return $extract;
1241         }
1242
1243         /**
1244          * Split text into lines and add it to extracts array
1245          *
1246          * @param array $extracts index -> $line
1247          * @param $count Integer
1248          * @param $text String
1249          */
1250         function splitAndAdd( &$extracts, &$count, $text ) {
1251                 $split = explode( "\n", $this->mCleanWikitext ? $this->removeWiki( $text ) : $text );
1252                 foreach ( $split as $line ) {
1253                         $tt = trim( $line );
1254                         if ( $tt ) {
1255                                 $extracts[$count++] = $tt;
1256                         }
1257                 }
1258         }
1259
1260         /**
1261          * Do manual case conversion for non-ascii chars
1262          *
1263          * @param $matches Array
1264          * @return string
1265          */
1266         function caseCallback( $matches ) {
1267                 global $wgContLang;
1268                 if ( strlen( $matches[0] ) > 1 ) {
1269                         return '[' . $wgContLang->lc( $matches[0] ) . $wgContLang->uc( $matches[0] ) . ']';
1270                 } else {
1271                         return $matches[0];
1272                 }
1273         }
1274
1275         /**
1276          * Extract part of the text from start to end, but by
1277          * not chopping up words
1278          * @param $text String
1279          * @param $start Integer
1280          * @param $end Integer
1281          * @param $posStart Integer: (out) actual start position
1282          * @param $posEnd Integer: (out) actual end position
1283          * @return String
1284          */
1285         function extract( $text, $start, $end, &$posStart = null, &$posEnd = null ) {
1286                 if ( $start != 0 ) {
1287                         $start = $this->position( $text, $start, 1 );
1288                 }
1289                 if ( $end >= strlen( $text ) ) {
1290                         $end = strlen( $text );
1291                 } else {
1292                         $end = $this->position( $text, $end );
1293                 }
1294
1295                 if ( !is_null( $posStart ) ) {
1296                         $posStart = $start;
1297                 }
1298                 if ( !is_null( $posEnd ) ) {
1299                         $posEnd = $end;
1300                 }
1301
1302                 if ( $end > $start ) {
1303                         return substr( $text, $start, $end - $start );
1304                 } else {
1305                         return '';
1306                 }
1307         }
1308
1309         /**
1310          * Find a nonletter near a point (index) in the text
1311          *
1312          * @param $text String
1313          * @param $point Integer
1314          * @param $offset Integer: offset to found index
1315          * @return Integer: nearest nonletter index, or beginning of utf8 char if none
1316          */
1317         function position( $text, $point, $offset = 0 ) {
1318                 $tolerance = 10;
1319                 $s = max( 0, $point - $tolerance );
1320                 $l = min( strlen( $text ), $point + $tolerance ) - $s;
1321                 $m = array();
1322                 if ( preg_match( '/[ ,.!?~!@#$%^&*\(\)+=\-\\\|\[\]"\'<>]/', substr( $text, $s, $l ), $m, PREG_OFFSET_CAPTURE ) ) {
1323                         return $m[0][1] + $s + $offset;
1324                 } else {
1325                         // check if point is on a valid first UTF8 char
1326                         $char = ord( $text[$point] );
1327                         while ( $char >= 0x80 && $char < 0xc0 ) {
1328                                 // skip trailing bytes
1329                                 $point++;
1330                                 if ( $point >= strlen( $text ) ) {
1331                                         return strlen( $text );
1332                                 }
1333                                 $char = ord( $text[$point] );
1334                         }
1335                         return $point;
1336
1337                 }
1338         }
1339
1340         /**
1341          * Search extracts for a pattern, and return snippets
1342          *
1343          * @param string $pattern regexp for matching lines
1344          * @param array $extracts extracts to search
1345          * @param $linesleft Integer: number of extracts to make
1346          * @param $contextchars Integer: length of snippet
1347          * @param array $out map for highlighted snippets
1348          * @param array $offsets map of starting points of snippets
1349          * @protected
1350          */
1351         function process( $pattern, $extracts, &$linesleft, &$contextchars, &$out, &$offsets ) {
1352                 if ( $linesleft == 0 ) {
1353                         return; // nothing to do
1354                 }
1355                 foreach ( $extracts as $index => $line ) {
1356                         if ( array_key_exists( $index, $out ) ) {
1357                                 continue; // this line already highlighted
1358                         }
1359
1360                         $m = array();
1361                         if ( !preg_match( $pattern, $line, $m, PREG_OFFSET_CAPTURE ) ) {
1362                                 continue;
1363                         }
1364
1365                         $offset = $m[0][1];
1366                         $len = strlen( $m[0][0] );
1367                         if ( $offset + $len < $contextchars ) {
1368                                 $begin = 0;
1369                         } elseif ( $len > $contextchars ) {
1370                                 $begin = $offset;
1371                         } else {
1372                                 $begin = $offset + intval( ( $len - $contextchars ) / 2 );
1373                         }
1374
1375                         $end = $begin + $contextchars;
1376
1377                         $posBegin = $begin;
1378                         // basic snippet from this line
1379                         $out[$index] = $this->extract( $line, $begin, $end, $posBegin );
1380                         $offsets[$index] = $posBegin;
1381                         $linesleft--;
1382                         if ( $linesleft == 0 ) {
1383                                 return;
1384                         }
1385                 }
1386         }
1387
1388         /**
1389          * Basic wikitext removal
1390          * @protected
1391          * @return mixed
1392          */
1393         function removeWiki( $text ) {
1394                 $fname = __METHOD__;
1395                 wfProfileIn( $fname );
1396
1397                 // $text = preg_replace( "/'{2,5}/", "", $text );
1398                 // $text = preg_replace( "/\[[a-z]+:\/\/[^ ]+ ([^]]+)\]/", "\\2", $text );
1399                 // $text = preg_replace( "/\[\[([^]|]+)\]\]/", "\\1", $text );
1400                 // $text = preg_replace( "/\[\[([^]]+\|)?([^|]]+)\]\]/", "\\2", $text );
1401                 // $text = preg_replace( "/\\{\\|(.*?)\\|\\}/", "", $text );
1402                 // $text = preg_replace( "/\\[\\[[A-Za-z_-]+:([^|]+?)\\]\\]/", "", $text );
1403                 $text = preg_replace( "/\\{\\{([^|]+?)\\}\\}/", "", $text );
1404                 $text = preg_replace( "/\\{\\{([^|]+\\|)(.*?)\\}\\}/", "\\2", $text );
1405                 $text = preg_replace( "/\\[\\[([^|]+?)\\]\\]/", "\\1", $text );
1406                 $text = preg_replace_callback( "/\\[\\[([^|]+\\|)(.*?)\\]\\]/", array( $this, 'linkReplace' ), $text );
1407                 // $text = preg_replace("/\\[\\[([^|]+\\|)(.*?)\\]\\]/", "\\2", $text);
1408                 $text = preg_replace( "/<\/?[^>]+>/", "", $text );
1409                 $text = preg_replace( "/'''''/", "", $text );
1410                 $text = preg_replace( "/('''|<\/?[iIuUbB]>)/", "", $text );
1411                 $text = preg_replace( "/''/", "", $text );
1412
1413                 wfProfileOut( $fname );
1414                 return $text;
1415         }
1416
1417         /**
1418          * callback to replace [[target|caption]] kind of links, if
1419          * the target is category or image, leave it
1420          *
1421          * @param $matches Array
1422          */
1423         function linkReplace( $matches ) {
1424                 $colon = strpos( $matches[1], ':' );
1425                 if ( $colon === false ) {
1426                         return $matches[2]; // replace with caption
1427                 }
1428                 global $wgContLang;
1429                 $ns = substr( $matches[1], 0, $colon );
1430                 $index = $wgContLang->getNsIndex( $ns );
1431                 if ( $index !== false && ( $index == NS_FILE || $index == NS_CATEGORY ) ) {
1432                         return $matches[0]; // return the whole thing
1433                 } else {
1434                         return $matches[2];
1435                 }
1436         }
1437
1438         /**
1439          * Simple & fast snippet extraction, but gives completely unrelevant
1440          * snippets
1441          *
1442          * @param $text String
1443          * @param $terms Array
1444          * @param $contextlines Integer
1445          * @param $contextchars Integer
1446          * @return String
1447          */
1448         public function highlightSimple( $text, $terms, $contextlines, $contextchars ) {
1449                 global $wgContLang;
1450                 $fname = __METHOD__;
1451
1452                 $lines = explode( "\n", $text );
1453
1454                 $terms = implode( '|', $terms );
1455                 $max = intval( $contextchars ) + 1;
1456                 $pat1 = "/(.*)($terms)(.{0,$max})/i";
1457
1458                 $lineno = 0;
1459
1460                 $extract = "";
1461                 wfProfileIn( "$fname-extract" );
1462                 foreach ( $lines as $line ) {
1463                         if ( 0 == $contextlines ) {
1464                                 break;
1465                         }
1466                         ++$lineno;
1467                         $m = array();
1468                         if ( ! preg_match( $pat1, $line, $m ) ) {
1469                                 continue;
1470                         }
1471                         --$contextlines;
1472                         // truncate function changes ... to relevant i18n message.
1473                         $pre = $wgContLang->truncate( $m[1], - $contextchars, '...', false );
1474
1475                         if ( count( $m ) < 3 ) {
1476                                 $post = '';
1477                         } else {
1478                                 $post = $wgContLang->truncate( $m[3], $contextchars, '...', false );
1479                         }
1480
1481                         $found = $m[2];
1482
1483                         $line = htmlspecialchars( $pre . $found . $post );
1484                         $pat2 = '/(' . $terms . ")/i";
1485                         $line = preg_replace( $pat2, "<span class='searchmatch'>\\1</span>", $line );
1486
1487                         $extract .= "${line}\n";
1488                 }
1489                 wfProfileOut( "$fname-extract" );
1490
1491                 return $extract;
1492         }
1493
1494 }
1495
1496 /**
1497  * Dummy class to be used when non-supported Database engine is present.
1498  * @todo FIXME: Dummy class should probably try something at least mildly useful,
1499  * such as a LIKE search through titles.
1500  * @ingroup Search
1501  */
1502 class SearchEngineDummy extends SearchEngine {
1503         // no-op
1504 }