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 use MediaWiki\MediaWikiServices;
  29
  30 /**
  31  * Contain a class for special pages
  32  * @ingroup Search
  33  */
  34 abstract class SearchEngine {
  35         /** @var string */
  36         public $prefix = '';
  37
  38         /** @var int[]|null */
  39         public $namespaces = [ NS_MAIN ];
  40
  41         /** @var int */
  42         protected $limit = 10;
  43
  44         /** @var int */
  45         protected $offset = 0;
  46
  47         /** @var array|string */
  48         protected $searchTerms = [];
  49
  50         /** @var bool */
  51         protected $showSuggestion = true;
  52         private $sort = 'relevance';
  53
  54         /** @var array Feature values */
  55         protected $features = [];
  56
  57         /** @const string profile type for completionSearch */
  58         const COMPLETION_PROFILE_TYPE = 'completionSearchProfile';
  59
  60         /** @const string profile type for query independent ranking features */
  61         const FT_QUERY_INDEP_PROFILE_TYPE = 'fulltextQueryIndepProfile';
  62
  63         /** @const int flag for legalSearchChars: includes all chars allowed in a search query */
  64         const CHARS_ALL = 1;
  65
  66         /** @const int flag for legalSearchChars: includes all chars allowed in a search term */
  67         const CHARS_NO_SYNTAX = 2;
  68
  69         /**
  70          * Perform a full text search query and return a result set.
  71          * If full text searches are not supported or disabled, return null.
  72          *
  73          * As of 1.32 overriding this function is deprecated. It will
  74          * be converted to final in 1.34. Override self::doSearchText().
  75          *
  76          * @param string $term Raw search term
  77          * @return SearchResultSet|Status|null
  78          */
  79         public function searchText( $term ) {
  80                 return $this->doSearchText( $term );
  81         }
  82
  83         /**
  84          * Perform a full text search query and return a result set.
  85          *
  86          * @param string $term Raw search term
  87          * @return SearchResultSet|Status|null
  88          * @since 1.32
  89          */
  90         protected function doSearchText( $term ) {
  91                 return null;
  92         }
  93
  94         /**
  95          * Perform a title search in the article archive.
  96          * NOTE: these results still should be filtered by
  97          * matching against PageArchive, permissions checks etc
  98          * The results returned by this methods are only sugegstions and
  99          * may not end up being shown to the user.
 100          *
 101          * As of 1.32 overriding this function is deprecated. It will
 102          * be converted to final in 1.34. Override self::doSearchArchiveTitle().
 103          *
 104          * @param string $term Raw search term
 105          * @return Status<Title[]>
 106          * @since 1.29
 107          */
 108         public function searchArchiveTitle( $term ) {
 109                 return $this->doSearchArchiveTitle( $term );
 110         }
 111
 112         /**
 113          * Perform a title search in the article archive.
 114          *
 115          * @param string $term Raw search term
 116          * @return Status<Title[]>
 117          * @since 1.32
 118          */
 119         protected function doSearchArchiveTitle( $term ) {
 120                 return Status::newGood( [] );
 121         }
 122
 123         /**
 124          * Perform a title-only search query and return a result set.
 125          * If title searches are not supported or disabled, return null.
 126          * STUB
 127          *
 128          * As of 1.32 overriding this function is deprecated. It will
 129          * be converted to final in 1.34. Override self::doSearchTitle().
 130          *
 131          * @param string $term Raw search term
 132          * @return SearchResultSet|null
 133          */
 134         public function searchTitle( $term ) {
 135                 return $this->doSearchTitle( $term );
 136         }
 137
 138         /**
 139          * Perform a title-only search query and return a result set.
 140          *
 141          * @param string $term Raw search term
 142          * @return SearchResultSet|null
 143          * @since 1.32
 144          */
 145         protected function doSearchTitle( $term ) {
 146                 return null;
 147         }
 148
 149         /**
 150          * @since 1.18
 151          * @param string $feature
 152          * @return bool
 153          */
 154         public function supports( $feature ) {
 155                 switch ( $feature ) {
 156                         case 'search-update':
 157                                 return true;
 158                         case 'title-suffix-filter':
 159                         default:
 160                                 return false;
 161                 }
 162         }
 163
 164         /**
 165          * Way to pass custom data for engines
 166          * @since 1.18
 167          * @param string $feature
 168          * @param mixed $data
 169          */
 170         public function setFeatureData( $feature, $data ) {
 171                 $this->features[$feature] = $data;
 172         }
 173
 174         /**
 175          * Way to retrieve custom data set by setFeatureData
 176          * or by the engine itself.
 177          * @since 1.29
 178          * @param string $feature feature name
 179          * @return mixed the feature value or null if unset
 180          */
 181         public function getFeatureData( $feature ) {
 182                 if ( isset( $this->features[$feature] ) ) {
 183                         return $this->features[$feature];
 184                 }
 185                 return null;
 186         }
 187
 188         /**
 189          * When overridden in derived class, performs database-specific conversions
 190          * on text to be used for searching or updating search index.
 191          * Default implementation does nothing (simply returns $string).
 192          *
 193          * @param string $string String to process
 194          * @return string
 195          */
 196         public function normalizeText( $string ) {
 197                 global $wgContLang;
 198
 199                 // Some languages such as Chinese require word segmentation
 200                 return $wgContLang->segmentByWord( $string );
 201         }
 202
 203         /**
 204          * Transform search term in cases when parts of the query came as different
 205          * GET params (when supported), e.g. for prefix queries:
 206          * search=test&prefix=Main_Page/Archive -> test prefix:Main Page/Archive
 207          * @param string $term
 208          * @return string
 209          */
 210         public function transformSearchTerm( $term ) {
 211                 return $term;
 212         }
 213
 214         /**
 215          * Get service class to finding near matches.
 216          * @param Config $config Configuration to use for the matcher.
 217          * @return SearchNearMatcher
 218          */
 219         public function getNearMatcher( Config $config ) {
 220                 global $wgContLang;
 221                 return new SearchNearMatcher( $config, $wgContLang );
 222         }
 223
 224         /**
 225          * Get near matcher for default SearchEngine.
 226          * @return SearchNearMatcher
 227          */
 228         protected static function defaultNearMatcher() {
 229                 $config = MediaWikiServices::getInstance()->getMainConfig();
 230                 return MediaWikiServices::getInstance()->newSearchEngine()->getNearMatcher( $config );
 231         }
 232
 233         /**
 234          * If an exact title match can be found, or a very slightly close match,
 235          * return the title. If no match, returns NULL.
 236          * @deprecated since 1.27; Use SearchEngine::getNearMatcher()
 237          * @param string $searchterm
 238          * @return Title
 239          */
 240         public static function getNearMatch( $searchterm ) {
 241                 return static::defaultNearMatcher()->getNearMatch( $searchterm );
 242         }
 243
 244         /**
 245          * Do a near match (see SearchEngine::getNearMatch) and wrap it into a
 246          * SearchResultSet.
 247          * @deprecated since 1.27; Use SearchEngine::getNearMatcher()
 248          * @param string $searchterm
 249          * @return SearchResultSet
 250          */
 251         public static function getNearMatchResultSet( $searchterm ) {
 252                 return static::defaultNearMatcher()->getNearMatchResultSet( $searchterm );
 253         }
 254
 255         /**
 256          * Get chars legal for search
 257          * NOTE: usage as static is deprecated and preserved only as BC measure
 258          * @param int $type type of search chars (see self::CHARS_ALL
 259          * and self::CHARS_NO_SYNTAX). Defaults to CHARS_ALL
 260          * @return string
 261          */
 262         public static function legalSearchChars( $type = self::CHARS_ALL ) {
 263                 return "A-Za-z_'.0-9\\x80-\\xFF\\-";
 264         }
 265
 266         /**
 267          * Set the maximum number of results to return
 268          * and how many to skip before returning the first.
 269          *
 270          * @param int $limit
 271          * @param int $offset
 272          */
 273         function setLimitOffset( $limit, $offset = 0 ) {
 274                 $this->limit = intval( $limit );
 275                 $this->offset = intval( $offset );
 276         }
 277
 278         /**
 279          * Set which namespaces the search should include.
 280          * Give an array of namespace index numbers.
 281          *
 282          * @param int[]|null $namespaces
 283          */
 284         function setNamespaces( $namespaces ) {
 285                 if ( $namespaces ) {
 286                         // Filter namespaces to only keep valid ones
 287                         $validNs = $this->searchableNamespaces();
 288                         $namespaces = array_filter( $namespaces, function ( $ns ) use( $validNs ) {
 289                                 return $ns < 0 || isset( $validNs[$ns] );
 290                         } );
 291                 } else {
 292                         $namespaces = [];
 293                 }
 294                 $this->namespaces = $namespaces;
 295         }
 296
 297         /**
 298          * Set whether the searcher should try to build a suggestion.  Note: some searchers
 299          * don't support building a suggestion in the first place and others don't respect
 300          * this flag.
 301          *
 302          * @param bool $showSuggestion Should the searcher try to build suggestions
 303          */
 304         function setShowSuggestion( $showSuggestion ) {
 305                 $this->showSuggestion = $showSuggestion;
 306         }
 307
 308         /**
 309          * Get the valid sort directions.  All search engines support 'relevance' but others
 310          * might support more. The default in all implementations should be 'relevance.'
 311          *
 312          * @since 1.25
 313          * @return string[] the valid sort directions for setSort
 314          */
 315         public function getValidSorts() {
 316                 return [ 'relevance' ];
 317         }
 318
 319         /**
 320          * Set the sort direction of the search results. Must be one returned by
 321          * SearchEngine::getValidSorts()
 322          *
 323          * @since 1.25
 324          * @throws InvalidArgumentException
 325          * @param string $sort sort direction for query result
 326          */
 327         public function setSort( $sort ) {
 328                 if ( !in_array( $sort, $this->getValidSorts() ) ) {
 329                         throw new InvalidArgumentException( "Invalid sort: $sort. " .
 330                                 "Must be one of: " . implode( ', ', $this->getValidSorts() ) );
 331                 }
 332                 $this->sort = $sort;
 333         }
 334
 335         /**
 336          * Get the sort direction of the search results
 337          *
 338          * @since 1.25
 339          * @return string
 340          */
 341         public function getSort() {
 342                 return $this->sort;
 343         }
 344
 345         /**
 346          * Parse some common prefixes: all (search everything)
 347          * or namespace names and set the list of namespaces
 348          * of this class accordingly.
 349          *
 350          * @param string $query
 351          * @return string
 352          */
 353         function replacePrefixes( $query ) {
 354                 $queryAndNs = self::parseNamespacePrefixes( $query );
 355                 if ( $queryAndNs === false ) {
 356                         return $query;
 357                 }
 358                 $this->namespaces = $queryAndNs[1];
 359                 return $queryAndNs[0];
 360         }
 361
 362         /**
 363          * Parse some common prefixes: all (search everything)
 364          * or namespace names
 365          *
 366          * @param string $query
 367          * @return false|array false if no namespace was extracted, an array
 368          * with the parsed query at index 0 and an array of namespaces at index
 369          * 1 (or null for all namespaces).
 370          */
 371         public static function parseNamespacePrefixes( $query ) {
 372                 global $wgContLang;
 373
 374                 $parsed = $query;
 375                 if ( strpos( $query, ':' ) === false ) { // nothing to do
 376                         return false;
 377                 }
 378                 $extractedNamespace = null;
 379                 $allkeywords = [];
 380
 381                 $allkeywords[] = wfMessage( 'searchall' )->inContentLanguage()->text() . ":";
 382                 // force all: so that we have a common syntax for all the wikis
 383                 if ( !in_array( 'all:', $allkeywords ) ) {
 384                         $allkeywords[] = 'all:';
 385                 }
 386
 387                 $allQuery = false;
 388                 foreach ( $allkeywords as $kw ) {
 389                         if ( strncmp( $query, $kw, strlen( $kw ) ) == 0 ) {
 390                                 $extractedNamespace = null;
 391                                 $parsed = substr( $query, strlen( $kw ) );
 392                                 $allQuery = true;
 393                                 break;
 394                         }
 395                 }
 396
 397                 if ( !$allQuery && strpos( $query, ':' ) !== false ) {
 398                         // TODO: should we unify with PrefixSearch::extractNamespace ?
 399                         $prefix = str_replace( ' ', '_', substr( $query, 0, strpos( $query, ':' ) ) );
 400                         $index = $wgContLang->getNsIndex( $prefix );
 401                         if ( $index !== false ) {
 402                                 $extractedNamespace = [ $index ];
 403                                 $parsed = substr( $query, strlen( $prefix ) + 1 );
 404                         } else {
 405                                 return false;
 406                         }
 407                 }
 408
 409                 if ( trim( $parsed ) == '' ) {
 410                         $parsed = $query; // prefix was the whole query
 411                 }
 412
 413                 return [ $parsed, $extractedNamespace ];
 414         }
 415
 416         /**
 417          * Find snippet highlight settings for all users
 418          * @return array Contextlines, contextchars
 419          */
 420         public static function userHighlightPrefs() {
 421                 $contextlines = 2; // Hardcode this. Old defaults sucked. :)
 422                 $contextchars = 75; // same as above.... :P
 423                 return [ $contextlines, $contextchars ];
 424         }
 425
 426         /**
 427          * Create or update the search index record for the given page.
 428          * Title and text should be pre-processed.
 429          * STUB
 430          *
 431          * @param int $id
 432          * @param string $title
 433          * @param string $text
 434          */
 435         function update( $id, $title, $text ) {
 436                 // no-op
 437         }
 438
 439         /**
 440          * Update a search index record's title only.
 441          * Title should be pre-processed.
 442          * STUB
 443          *
 444          * @param int $id
 445          * @param string $title
 446          */
 447         function updateTitle( $id, $title ) {
 448                 // no-op
 449         }
 450
 451         /**
 452          * Delete an indexed page
 453          * Title should be pre-processed.
 454          * STUB
 455          *
 456          * @param int $id Page id that was deleted
 457          * @param string $title Title of page that was deleted
 458          */
 459         function delete( $id, $title ) {
 460                 // no-op
 461         }
 462
 463         /**
 464          * Get the raw text for updating the index from a content object
 465          * Nicer search backends could possibly do something cooler than
 466          * just returning raw text
 467          *
 468          * @todo This isn't ideal, we'd really like to have content-specific handling here
 469          * @param Title $t Title we're indexing
 470          * @param Content $c Content of the page to index
 471          * @return string
 472          */
 473         public function getTextFromContent( Title $t, Content $c = null ) {
 474                 return $c ? $c->getTextForSearchIndex() : '';
 475         }
 476
 477         /**
 478          * If an implementation of SearchEngine handles all of its own text processing
 479          * in getTextFromContent() and doesn't require SearchUpdate::updateText()'s
 480          * rather silly handling, it should return true here instead.
 481          *
 482          * @return bool
 483          */
 484         public function textAlreadyUpdatedForIndex() {
 485                 return false;
 486         }
 487
 488         /**
 489          * Makes search simple string if it was namespaced.
 490          * Sets namespaces of the search to namespaces extracted from string.
 491          * @param string $search
 492          * @return string Simplified search string
 493          */
 494         protected function normalizeNamespaces( $search ) {
 495                 // Find a Title which is not an interwiki and is in NS_MAIN
 496                 $title = Title::newFromText( $search );
 497                 $ns = $this->namespaces;
 498                 if ( $title && !$title->isExternal() ) {
 499                         $ns = [ $title->getNamespace() ];
 500                         $search = $title->getText();
 501                         if ( $ns[0] == NS_MAIN ) {
 502                                 $ns = $this->namespaces; // no explicit prefix, use default namespaces
 503                                 Hooks::run( 'PrefixSearchExtractNamespace', [ &$ns, &$search ] );
 504                         }
 505                 } else {
 506                         $title = Title::newFromText( $search . 'Dummy' );
 507                         if ( $title && $title->getText() == 'Dummy'
 508                                         && $title->getNamespace() != NS_MAIN
 509                                         && !$title->isExternal()
 510                         ) {
 511                                 $ns = [ $title->getNamespace() ];
 512                                 $search = '';
 513                         } else {
 514                                 Hooks::run( 'PrefixSearchExtractNamespace', [ &$ns, &$search ] );
 515                         }
 516                 }
 517
 518                 $ns = array_map( function ( $space ) {
 519                         return $space == NS_MEDIA ? NS_FILE : $space;
 520                 }, $ns );
 521
 522                 $this->setNamespaces( $ns );
 523                 return $search;
 524         }
 525
 526         /**
 527          * Perform a completion search.
 528          * Does not resolve namespaces and does not check variants.
 529          * Search engine implementations may want to override this function.
 530          * @param string $search
 531          * @return SearchSuggestionSet
 532          */
 533         protected function completionSearchBackend( $search ) {
 534                 $results = [];
 535
 536                 $search = trim( $search );
 537
 538                 if ( !in_array( NS_SPECIAL, $this->namespaces ) && // We do not run hook on Special: search
 539                          !Hooks::run( 'PrefixSearchBackend',
 540                                 [ $this->namespaces, $search, $this->limit, &$results, $this->offset ]
 541                 ) ) {
 542                         // False means hook worked.
 543                         // FIXME: Yes, the API is weird. That's why it is going to be deprecated.
 544
 545                         return SearchSuggestionSet::fromStrings( $results );
 546                 } else {
 547                         // Hook did not do the job, use default simple search
 548                         $results = $this->simplePrefixSearch( $search );
 549                         return SearchSuggestionSet::fromTitles( $results );
 550                 }
 551         }
 552
 553         /**
 554          * Perform a completion search.
 555          * @param string $search
 556          * @return SearchSuggestionSet
 557          */
 558         public function completionSearch( $search ) {
 559                 if ( trim( $search ) === '' ) {
 560                         return SearchSuggestionSet::emptySuggestionSet(); // Return empty result
 561                 }
 562                 $search = $this->normalizeNamespaces( $search );
 563                 return $this->processCompletionResults( $search, $this->completionSearchBackend( $search ) );
 564         }
 565
 566         /**
 567          * Perform a completion search with variants.
 568          * @param string $search
 569          * @return SearchSuggestionSet
 570          */
 571         public function completionSearchWithVariants( $search ) {
 572                 if ( trim( $search ) === '' ) {
 573                         return SearchSuggestionSet::emptySuggestionSet(); // Return empty result
 574                 }
 575                 $search = $this->normalizeNamespaces( $search );
 576
 577                 $results = $this->completionSearchBackend( $search );
 578                 $fallbackLimit = $this->limit - $results->getSize();
 579                 if ( $fallbackLimit > 0 ) {
 580                         global $wgContLang;
 581
 582                         $fallbackSearches = $wgContLang->autoConvertToAllVariants( $search );
 583                         $fallbackSearches = array_diff( array_unique( $fallbackSearches ), [ $search ] );
 584
 585                         foreach ( $fallbackSearches as $fbs ) {
 586                                 $this->setLimitOffset( $fallbackLimit );
 587                                 $fallbackSearchResult = $this->completionSearch( $fbs );
 588                                 $results->appendAll( $fallbackSearchResult );
 589                                 $fallbackLimit -= $fallbackSearchResult->getSize();
 590                                 if ( $fallbackLimit <= 0 ) {
 591                                         break;
 592                                 }
 593                         }
 594                 }
 595                 return $this->processCompletionResults( $search, $results );
 596         }
 597
 598         /**
 599          * Extract titles from completion results
 600          * @param SearchSuggestionSet $completionResults
 601          * @return Title[]
 602          */
 603         public function extractTitles( SearchSuggestionSet $completionResults ) {
 604                 return $completionResults->map( function ( SearchSuggestion $sugg ) {
 605                         return $sugg->getSuggestedTitle();
 606                 } );
 607         }
 608
 609         /**
 610          * Process completion search results.
 611          * Resolves the titles and rescores.
 612          * @param string $search
 613          * @param SearchSuggestionSet $suggestions
 614          * @return SearchSuggestionSet
 615          */
 616         protected function processCompletionResults( $search, SearchSuggestionSet $suggestions ) {
 617                 $search = trim( $search );
 618                 // preload the titles with LinkBatch
 619                 $titles = $suggestions->map( function ( SearchSuggestion $sugg ) {
 620                         return $sugg->getSuggestedTitle();
 621                 } );
 622                 $lb = new LinkBatch( $titles );
 623                 $lb->setCaller( __METHOD__ );
 624                 $lb->execute();
 625
 626                 $results = $suggestions->map( function ( SearchSuggestion $sugg ) {
 627                         return $sugg->getSuggestedTitle()->getPrefixedText();
 628                 } );
 629
 630                 if ( $this->offset === 0 ) {
 631                         // Rescore results with an exact title match
 632                         // NOTE: in some cases like cross-namespace redirects
 633                         // (frequently used as shortcuts e.g. WP:WP on huwiki) some
 634                         // backends like Cirrus will return no results. We should still
 635                         // try an exact title match to workaround this limitation
 636                         $rescorer = new SearchExactMatchRescorer();
 637                         $rescoredResults = $rescorer->rescore( $search, $this->namespaces, $results, $this->limit );
 638                 } else {
 639                         // No need to rescore if offset is not 0
 640                         // The exact match must have been returned at position 0
 641                         // if it existed.
 642                         $rescoredResults = $results;
 643                 }
 644
 645                 if ( count( $rescoredResults ) > 0 ) {
 646                         $found = array_search( $rescoredResults[0], $results );
 647                         if ( $found === false ) {
 648                                 // If the first result is not in the previous array it
 649                                 // means that we found a new exact match
 650                                 $exactMatch = SearchSuggestion::fromTitle( 0, Title::newFromText( $rescoredResults[0] ) );
 651                                 $suggestions->prepend( $exactMatch );
 652                                 $suggestions->shrink( $this->limit );
 653                         } else {
 654                                 // if the first result is not the same we need to rescore
 655                                 if ( $found > 0 ) {
 656                                         $suggestions->rescore( $found );
 657                                 }
 658                         }
 659                 }
 660
 661                 return $suggestions;
 662         }
 663
 664         /**
 665          * Simple prefix search for subpages.
 666          * @param string $search
 667          * @return Title[]
 668          */
 669         public function defaultPrefixSearch( $search ) {
 670                 if ( trim( $search ) === '' ) {
 671                         return [];
 672                 }
 673
 674                 $search = $this->normalizeNamespaces( $search );
 675                 return $this->simplePrefixSearch( $search );
 676         }
 677
 678         /**
 679          * Call out to simple search backend.
 680          * Defaults to TitlePrefixSearch.
 681          * @param string $search
 682          * @return Title[]
 683          */
 684         protected function simplePrefixSearch( $search ) {
 685                 // Use default database prefix search
 686                 $backend = new TitlePrefixSearch;
 687                 return $backend->defaultSearchBackend( $this->namespaces, $search, $this->limit, $this->offset );
 688         }
 689
 690         /**
 691          * Make a list of searchable namespaces and their canonical names.
 692          * @deprecated since 1.27; use SearchEngineConfig::searchableNamespaces()
 693          * @return array
 694          */
 695         public static function searchableNamespaces() {
 696                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->searchableNamespaces();
 697         }
 698
 699         /**
 700          * Extract default namespaces to search from the given user's
 701          * settings, returning a list of index numbers.
 702          * @deprecated since 1.27; use SearchEngineConfig::userNamespaces()
 703          * @param user $user
 704          * @return array
 705          */
 706         public static function userNamespaces( $user ) {
 707                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->userNamespaces( $user );
 708         }
 709
 710         /**
 711          * An array of namespaces indexes to be searched by default
 712          * @deprecated since 1.27; use SearchEngineConfig::defaultNamespaces()
 713          * @return array
 714          */
 715         public static function defaultNamespaces() {
 716                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->defaultNamespaces();
 717         }
 718
 719         /**
 720          * Get a list of namespace names useful for showing in tooltips
 721          * and preferences
 722          * @deprecated since 1.27; use SearchEngineConfig::namespacesAsText()
 723          * @param array $namespaces
 724          * @return array
 725          */
 726         public static function namespacesAsText( $namespaces ) {
 727                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->namespacesAsText( $namespaces );
 728         }
 729
 730         /**
 731          * Load up the appropriate search engine class for the currently
 732          * active database backend, and return a configured instance.
 733          * @deprecated since 1.27; Use SearchEngineFactory::create
 734          * @param string $type Type of search backend, if not the default
 735          * @return SearchEngine
 736          */
 737         public static function create( $type = null ) {
 738                 return MediaWikiServices::getInstance()->getSearchEngineFactory()->create( $type );
 739         }
 740
 741         /**
 742          * Return the search engines we support. If only $wgSearchType
 743          * is set, it'll be an array of just that one item.
 744          * @deprecated since 1.27; use SearchEngineConfig::getSearchTypes()
 745          * @return array
 746          */
 747         public static function getSearchTypes() {
 748                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->getSearchTypes();
 749         }
 750
 751         /**
 752          * Get a list of supported profiles.
 753          * Some search engine implementations may expose specific profiles to fine-tune
 754          * its behaviors.
 755          * The profile can be passed as a feature data with setFeatureData( $profileType, $profileName )
 756          * The array returned by this function contains the following keys:
 757          * - name: the profile name to use with setFeatureData
 758          * - desc-message: the i18n description
 759          * - default: set to true if this profile is the default
 760          *
 761          * @since 1.28
 762          * @param string $profileType the type of profiles
 763          * @param User|null $user the user requesting the list of profiles
 764          * @return array|null the list of profiles or null if none available
 765          */
 766         public function getProfiles( $profileType, User $user = null ) {
 767                 return null;
 768         }
 769
 770         /**
 771          * Create a search field definition.
 772          * Specific search engines should override this method to create search fields.
 773          * @param string $name
 774          * @param int $type One of the types in SearchIndexField::INDEX_TYPE_*
 775          * @return SearchIndexField
 776          * @since 1.28
 777          */
 778         public function makeSearchFieldMapping( $name, $type ) {
 779                 return new NullIndexField();
 780         }
 781
 782         /**
 783          * Get fields for search index
 784          * @since 1.28
 785          * @return SearchIndexField[] Index field definitions for all content handlers
 786          */
 787         public function getSearchIndexFields() {
 788                 $models = ContentHandler::getContentModels();
 789                 $fields = [];
 790                 $seenHandlers = new SplObjectStorage();
 791                 foreach ( $models as $model ) {
 792                         try {
 793                                 $handler = ContentHandler::getForModelID( $model );
 794                         }
 795                         catch ( MWUnknownContentModelException $e ) {
 796                                 // If we can find no handler, ignore it
 797                                 continue;
 798                         }
 799                         // Several models can have the same handler, so avoid processing it repeatedly
 800                         if ( $seenHandlers->contains( $handler ) ) {
 801                                 // We already did this one
 802                                 continue;
 803                         }
 804                         $seenHandlers->attach( $handler );
 805                         $handlerFields = $handler->getFieldsForSearchIndex( $this );
 806                         foreach ( $handlerFields as $fieldName => $fieldData ) {
 807                                 if ( empty( $fields[$fieldName] ) ) {
 808                                         $fields[$fieldName] = $fieldData;
 809                                 } else {
 810                                         // TODO: do we allow some clashes with the same type or reject all of them?
 811                                         $mergeDef = $fields[$fieldName]->merge( $fieldData );
 812                                         if ( !$mergeDef ) {
 813                                                 throw new InvalidArgumentException( "Duplicate field $fieldName for model $model" );
 814                                         }
 815                                         $fields[$fieldName] = $mergeDef;
 816                                 }
 817                         }
 818                 }
 819                 // Hook to allow extensions to produce search mapping fields
 820                 Hooks::run( 'SearchIndexFields', [ &$fields, $this ] );
 821                 return $fields;
 822         }
 823
 824         /**
 825          * Augment search results with extra data.
 826          *
 827          * @param SearchResultSet $resultSet
 828          */
 829         public function augmentSearchResults( SearchResultSet $resultSet ) {
 830                 $setAugmentors = [];
 831                 $rowAugmentors = [];
 832                 Hooks::run( "SearchResultsAugment", [ &$setAugmentors, &$rowAugmentors ] );
 833
 834                 if ( !$setAugmentors && !$rowAugmentors ) {
 835                         // We're done here
 836                         return;
 837                 }
 838
 839                 // Convert row augmentors to set augmentor
 840                 foreach ( $rowAugmentors as $name => $row ) {
 841                         if ( isset( $setAugmentors[$name] ) ) {
 842                                 throw new InvalidArgumentException( "Both row and set augmentors are defined for $name" );
 843                         }
 844                         $setAugmentors[$name] = new PerRowAugmentor( $row );
 845                 }
 846
 847                 foreach ( $setAugmentors as $name => $augmentor ) {
 848                         $data = $augmentor->augmentAll( $resultSet );
 849                         if ( $data ) {
 850                                 $resultSet->setAugmentedData( $name, $data );
 851                         }
 852                 }
 853         }
 854 }
 855
 856 /**
 857  * Dummy class to be used when non-supported Database engine is present.
 858  * @todo FIXME: Dummy class should probably try something at least mildly useful,
 859  * such as a LIKE search through titles.
 860  * @ingroup Search
 861  */
 862 class SearchEngineDummy extends SearchEngine {
 863         // no-op
 864 }