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         /**
  64          * Perform a full text search query and return a result set.
  65          * If full text searches are not supported or disabled, return null.
  66          * STUB
  67          *
  68          * @param string $term Raw search term
  69          * @return SearchResultSet|Status|null
  70          */
  71         function searchText( $term ) {
  72                 return null;
  73         }
  74
  75         /**
  76          * Perform a title search in the article archive.
  77          * NOTE: these results still should be filtered by
  78          * matching against PageArchive, permissions checks etc
  79          * The results returned by this methods are only sugegstions and
  80          * may not end up being shown to the user.
  81          *
  82          * @param string $term Raw search term
  83          * @return Status<Title[]>
  84          * @since 1.29
  85          */
  86         function searchArchiveTitle( $term ) {
  87                 return Status::newGood( [] );
  88         }
  89
  90         /**
  91          * Perform a title-only search query and return a result set.
  92          * If title searches are not supported or disabled, return null.
  93          * STUB
  94          *
  95          * @param string $term Raw search term
  96          * @return SearchResultSet|null
  97          */
  98         function searchTitle( $term ) {
  99                 return null;
 100         }
 101
 102         /**
 103          * @since 1.18
 104          * @param string $feature
 105          * @return bool
 106          */
 107         public function supports( $feature ) {
 108                 switch ( $feature ) {
 109                 case 'search-update':
 110                         return true;
 111                 case 'title-suffix-filter':
 112                 default:
 113                         return false;
 114                 }
 115         }
 116
 117         /**
 118          * Way to pass custom data for engines
 119          * @since 1.18
 120          * @param string $feature
 121          * @param mixed $data
 122          */
 123         public function setFeatureData( $feature, $data ) {
 124                 $this->features[$feature] = $data;
 125         }
 126
 127         /**
 128          * Way to retrieve custom data set by setFeatureData
 129          * or by the engine itself.
 130          * @since 1.29
 131          * @param string $feature feature name
 132          * @return mixed the feature value or null if unset
 133          */
 134         public function getFeatureData( $feature ) {
 135                 if ( isset ( $this->features[$feature] ) ) {
 136                         return $this->features[$feature];
 137                 }
 138                 return null;
 139         }
 140
 141         /**
 142          * When overridden in derived class, performs database-specific conversions
 143          * on text to be used for searching or updating search index.
 144          * Default implementation does nothing (simply returns $string).
 145          *
 146          * @param string $string String to process
 147          * @return string
 148          */
 149         public function normalizeText( $string ) {
 150                 global $wgContLang;
 151
 152                 // Some languages such as Chinese require word segmentation
 153                 return $wgContLang->segmentByWord( $string );
 154         }
 155
 156         /**
 157          * Transform search term in cases when parts of the query came as different
 158          * GET params (when supported), e.g. for prefix queries:
 159          * search=test&prefix=Main_Page/Archive -> test prefix:Main Page/Archive
 160          * @param string $term
 161          * @return string
 162          */
 163         public function transformSearchTerm( $term ) {
 164                 return $term;
 165         }
 166
 167         /**
 168          * Get service class to finding near matches.
 169          * @param Config $config Configuration to use for the matcher.
 170          * @return SearchNearMatcher
 171          */
 172         public function getNearMatcher( Config $config ) {
 173                 global $wgContLang;
 174                 return new SearchNearMatcher( $config, $wgContLang );
 175         }
 176
 177         /**
 178          * Get near matcher for default SearchEngine.
 179          * @return SearchNearMatcher
 180          */
 181         protected static function defaultNearMatcher() {
 182                 $config = MediaWikiServices::getInstance()->getMainConfig();
 183                 return MediaWikiServices::getInstance()->newSearchEngine()->getNearMatcher( $config );
 184         }
 185
 186         /**
 187          * If an exact title match can be found, or a very slightly close match,
 188          * return the title. If no match, returns NULL.
 189          * @deprecated since 1.27; Use SearchEngine::getNearMatcher()
 190          * @param string $searchterm
 191          * @return Title
 192          */
 193         public static function getNearMatch( $searchterm ) {
 194                 return static::defaultNearMatcher()->getNearMatch( $searchterm );
 195         }
 196
 197         /**
 198          * Do a near match (see SearchEngine::getNearMatch) and wrap it into a
 199          * SearchResultSet.
 200          * @deprecated since 1.27; Use SearchEngine::getNearMatcher()
 201          * @param string $searchterm
 202          * @return SearchResultSet
 203          */
 204         public static function getNearMatchResultSet( $searchterm ) {
 205                 return static::defaultNearMatcher()->getNearMatchResultSet( $searchterm );
 206         }
 207
 208         /**
 209          * Get chars legal for search (at query time).
 210          * NOTE: usage as static is deprecated and preserved only as BC measure
 211          * @return string
 212          */
 213         public static function legalSearchChars() {
 214                 return "A-Za-z_'.0-9\\x80-\\xFF\\-";
 215         }
 216
 217         /**
 218          * Get chars legal for search (at index time).
 219          *
 220          * @since 1.30
 221          * @return string
 222          */
 223         public function legalSearchCharsForUpdate() {
 224                 return static::legalSearchChars();
 225         }
 226
 227         /**
 228          * Set the maximum number of results to return
 229          * and how many to skip before returning the first.
 230          *
 231          * @param int $limit
 232          * @param int $offset
 233          */
 234         function setLimitOffset( $limit, $offset = 0 ) {
 235                 $this->limit = intval( $limit );
 236                 $this->offset = intval( $offset );
 237         }
 238
 239         /**
 240          * Set which namespaces the search should include.
 241          * Give an array of namespace index numbers.
 242          *
 243          * @param int[]|null $namespaces
 244          */
 245         function setNamespaces( $namespaces ) {
 246                 if ( $namespaces ) {
 247                         // Filter namespaces to only keep valid ones
 248                         $validNs = $this->searchableNamespaces();
 249                         $namespaces = array_filter( $namespaces, function ( $ns ) use( $validNs ) {
 250                                 return $ns < 0 || isset( $validNs[$ns] );
 251                         } );
 252                 } else {
 253                         $namespaces = [];
 254                 }
 255                 $this->namespaces = $namespaces;
 256         }
 257
 258         /**
 259          * Set whether the searcher should try to build a suggestion.  Note: some searchers
 260          * don't support building a suggestion in the first place and others don't respect
 261          * this flag.
 262          *
 263          * @param bool $showSuggestion Should the searcher try to build suggestions
 264          */
 265         function setShowSuggestion( $showSuggestion ) {
 266                 $this->showSuggestion = $showSuggestion;
 267         }
 268
 269         /**
 270          * Get the valid sort directions.  All search engines support 'relevance' but others
 271          * might support more. The default in all implementations should be 'relevance.'
 272          *
 273          * @since 1.25
 274          * @return array(string) the valid sort directions for setSort
 275          */
 276         public function getValidSorts() {
 277                 return [ 'relevance' ];
 278         }
 279
 280         /**
 281          * Set the sort direction of the search results. Must be one returned by
 282          * SearchEngine::getValidSorts()
 283          *
 284          * @since 1.25
 285          * @throws InvalidArgumentException
 286          * @param string $sort sort direction for query result
 287          */
 288         public function setSort( $sort ) {
 289                 if ( !in_array( $sort, $this->getValidSorts() ) ) {
 290                         throw new InvalidArgumentException( "Invalid sort: $sort. " .
 291                                 "Must be one of: " . implode( ', ', $this->getValidSorts() ) );
 292                 }
 293                 $this->sort = $sort;
 294         }
 295
 296         /**
 297          * Get the sort direction of the search results
 298          *
 299          * @since 1.25
 300          * @return string
 301          */
 302         public function getSort() {
 303                 return $this->sort;
 304         }
 305
 306         /**
 307          * Parse some common prefixes: all (search everything)
 308          * or namespace names and set the list of namespaces
 309          * of this class accordingly.
 310          *
 311          * @param string $query
 312          * @return string
 313          */
 314         function replacePrefixes( $query ) {
 315                 $queryAndNs = self::parseNamespacePrefixes( $query );
 316                 if ( $queryAndNs === false ) {
 317                         return $query;
 318                 }
 319                 $this->namespaces = $queryAndNs[1];
 320                 return $queryAndNs[0];
 321         }
 322
 323         /**
 324          * Parse some common prefixes: all (search everything)
 325          * or namespace names
 326          *
 327          * @param string $query
 328          * @return false|array false if no namespace was extracted, an array
 329          * with the parsed query at index 0 and an array of namespaces at index
 330          * 1 (or null for all namespaces).
 331          */
 332         public static function parseNamespacePrefixes( $query ) {
 333                 global $wgContLang;
 334
 335                 $parsed = $query;
 336                 if ( strpos( $query, ':' ) === false ) { // nothing to do
 337                         return false;
 338                 }
 339                 $extractedNamespace = null;
 340
 341                 $allkeyword = wfMessage( 'searchall' )->inContentLanguage()->text() . ":";
 342                 if ( strncmp( $query, $allkeyword, strlen( $allkeyword ) ) == 0 ) {
 343                         $extractedNamespace = null;
 344                         $parsed = substr( $query, strlen( $allkeyword ) );
 345                 } elseif ( strpos( $query, ':' ) !== false ) {
 346                         // TODO: should we unify with PrefixSearch::extractNamespace ?
 347                         $prefix = str_replace( ' ', '_', substr( $query, 0, strpos( $query, ':' ) ) );
 348                         $index = $wgContLang->getNsIndex( $prefix );
 349                         if ( $index !== false ) {
 350                                 $extractedNamespace = [ $index ];
 351                                 $parsed = substr( $query, strlen( $prefix ) + 1 );
 352                         } else {
 353                                 return false;
 354                         }
 355                 }
 356
 357                 if ( trim( $parsed ) == '' ) {
 358                         $parsed = $query; // prefix was the whole query
 359                 }
 360
 361                 return [ $parsed, $extractedNamespace ];
 362         }
 363
 364         /**
 365          * Find snippet highlight settings for all users
 366          * @return array Contextlines, contextchars
 367          */
 368         public static function userHighlightPrefs() {
 369                 $contextlines = 2; // Hardcode this. Old defaults sucked. :)
 370                 $contextchars = 75; // same as above.... :P
 371                 return [ $contextlines, $contextchars ];
 372         }
 373
 374         /**
 375          * Create or update the search index record for the given page.
 376          * Title and text should be pre-processed.
 377          * STUB
 378          *
 379          * @param int $id
 380          * @param string $title
 381          * @param string $text
 382          */
 383         function update( $id, $title, $text ) {
 384                 // no-op
 385         }
 386
 387         /**
 388          * Update a search index record's title only.
 389          * Title should be pre-processed.
 390          * STUB
 391          *
 392          * @param int $id
 393          * @param string $title
 394          */
 395         function updateTitle( $id, $title ) {
 396                 // no-op
 397         }
 398
 399         /**
 400          * Delete an indexed page
 401          * Title should be pre-processed.
 402          * STUB
 403          *
 404          * @param int $id Page id that was deleted
 405          * @param string $title Title of page that was deleted
 406          */
 407         function delete( $id, $title ) {
 408                 // no-op
 409         }
 410
 411         /**
 412          * Get OpenSearch suggestion template
 413          *
 414          * @deprecated since 1.25
 415          * @return string
 416          */
 417         public static function getOpenSearchTemplate() {
 418                 wfDeprecated( __METHOD__, '1.25' );
 419                 return ApiOpenSearch::getOpenSearchTemplate( 'application/x-suggestions+json' );
 420         }
 421
 422         /**
 423          * Get the raw text for updating the index from a content object
 424          * Nicer search backends could possibly do something cooler than
 425          * just returning raw text
 426          *
 427          * @todo This isn't ideal, we'd really like to have content-specific handling here
 428          * @param Title $t Title we're indexing
 429          * @param Content $c Content of the page to index
 430          * @return string
 431          */
 432         public function getTextFromContent( Title $t, Content $c = null ) {
 433                 return $c ? $c->getTextForSearchIndex() : '';
 434         }
 435
 436         /**
 437          * If an implementation of SearchEngine handles all of its own text processing
 438          * in getTextFromContent() and doesn't require SearchUpdate::updateText()'s
 439          * rather silly handling, it should return true here instead.
 440          *
 441          * @return bool
 442          */
 443         public function textAlreadyUpdatedForIndex() {
 444                 return false;
 445         }
 446
 447         /**
 448          * Makes search simple string if it was namespaced.
 449          * Sets namespaces of the search to namespaces extracted from string.
 450          * @param string $search
 451          * @return string Simplified search string
 452          */
 453         protected function normalizeNamespaces( $search ) {
 454                 // Find a Title which is not an interwiki and is in NS_MAIN
 455                 $title = Title::newFromText( $search );
 456                 $ns = $this->namespaces;
 457                 if ( $title && !$title->isExternal() ) {
 458                         $ns = [ $title->getNamespace() ];
 459                         $search = $title->getText();
 460                         if ( $ns[0] == NS_MAIN ) {
 461                                 $ns = $this->namespaces; // no explicit prefix, use default namespaces
 462                                 Hooks::run( 'PrefixSearchExtractNamespace', [ &$ns, &$search ] );
 463                         }
 464                 } else {
 465                         $title = Title::newFromText( $search . 'Dummy' );
 466                         if ( $title && $title->getText() == 'Dummy'
 467                                         && $title->getNamespace() != NS_MAIN
 468                                         && !$title->isExternal()
 469                         ) {
 470                                 $ns = [ $title->getNamespace() ];
 471                                 $search = '';
 472                         } else {
 473                                 Hooks::run( 'PrefixSearchExtractNamespace', [ &$ns, &$search ] );
 474                         }
 475                 }
 476
 477                 $ns = array_map( function ( $space ) {
 478                         return $space == NS_MEDIA ? NS_FILE : $space;
 479                 }, $ns );
 480
 481                 $this->setNamespaces( $ns );
 482                 return $search;
 483         }
 484
 485         /**
 486          * Perform a completion search.
 487          * Does not resolve namespaces and does not check variants.
 488          * Search engine implementations may want to override this function.
 489          * @param string $search
 490          * @return SearchSuggestionSet
 491          */
 492         protected function completionSearchBackend( $search ) {
 493                 $results = [];
 494
 495                 $search = trim( $search );
 496
 497                 if ( !in_array( NS_SPECIAL, $this->namespaces ) && // We do not run hook on Special: search
 498                          !Hooks::run( 'PrefixSearchBackend',
 499                                 [ $this->namespaces, $search, $this->limit, &$results, $this->offset ]
 500                 ) ) {
 501                         // False means hook worked.
 502                         // FIXME: Yes, the API is weird. That's why it is going to be deprecated.
 503
 504                         return SearchSuggestionSet::fromStrings( $results );
 505                 } else {
 506                         // Hook did not do the job, use default simple search
 507                         $results = $this->simplePrefixSearch( $search );
 508                         return SearchSuggestionSet::fromTitles( $results );
 509                 }
 510         }
 511
 512         /**
 513          * Perform a completion search.
 514          * @param string $search
 515          * @return SearchSuggestionSet
 516          */
 517         public function completionSearch( $search ) {
 518                 if ( trim( $search ) === '' ) {
 519                         return SearchSuggestionSet::emptySuggestionSet(); // Return empty result
 520                 }
 521                 $search = $this->normalizeNamespaces( $search );
 522                 return $this->processCompletionResults( $search, $this->completionSearchBackend( $search ) );
 523         }
 524
 525         /**
 526          * Perform a completion search with variants.
 527          * @param string $search
 528          * @return SearchSuggestionSet
 529          */
 530         public function completionSearchWithVariants( $search ) {
 531                 if ( trim( $search ) === '' ) {
 532                         return SearchSuggestionSet::emptySuggestionSet(); // Return empty result
 533                 }
 534                 $search = $this->normalizeNamespaces( $search );
 535
 536                 $results = $this->completionSearchBackend( $search );
 537                 $fallbackLimit = $this->limit - $results->getSize();
 538                 if ( $fallbackLimit > 0 ) {
 539                         global $wgContLang;
 540
 541                         $fallbackSearches = $wgContLang->autoConvertToAllVariants( $search );
 542                         $fallbackSearches = array_diff( array_unique( $fallbackSearches ), [ $search ] );
 543
 544                         foreach ( $fallbackSearches as $fbs ) {
 545                                 $this->setLimitOffset( $fallbackLimit );
 546                                 $fallbackSearchResult = $this->completionSearch( $fbs );
 547                                 $results->appendAll( $fallbackSearchResult );
 548                                 $fallbackLimit -= count( $fallbackSearchResult );
 549                                 if ( $fallbackLimit <= 0 ) {
 550                                         break;
 551                                 }
 552                         }
 553                 }
 554                 return $this->processCompletionResults( $search, $results );
 555         }
 556
 557         /**
 558          * Extract titles from completion results
 559          * @param SearchSuggestionSet $completionResults
 560          * @return Title[]
 561          */
 562         public function extractTitles( SearchSuggestionSet $completionResults ) {
 563                 return $completionResults->map( function ( SearchSuggestion $sugg ) {
 564                         return $sugg->getSuggestedTitle();
 565                 } );
 566         }
 567
 568         /**
 569          * Process completion search results.
 570          * Resolves the titles and rescores.
 571          * @param SearchSuggestionSet $suggestions
 572          * @return SearchSuggestionSet
 573          */
 574         protected function processCompletionResults( $search, SearchSuggestionSet $suggestions ) {
 575                 $search = trim( $search );
 576                 // preload the titles with LinkBatch
 577                 $titles = $suggestions->map( function ( SearchSuggestion $sugg ) {
 578                         return $sugg->getSuggestedTitle();
 579                 } );
 580                 $lb = new LinkBatch( $titles );
 581                 $lb->setCaller( __METHOD__ );
 582                 $lb->execute();
 583
 584                 $results = $suggestions->map( function ( SearchSuggestion $sugg ) {
 585                         return $sugg->getSuggestedTitle()->getPrefixedText();
 586                 } );
 587
 588                 if ( $this->offset === 0 ) {
 589                         // Rescore results with an exact title match
 590                         // NOTE: in some cases like cross-namespace redirects
 591                         // (frequently used as shortcuts e.g. WP:WP on huwiki) some
 592                         // backends like Cirrus will return no results. We should still
 593                         // try an exact title match to workaround this limitation
 594                         $rescorer = new SearchExactMatchRescorer();
 595                         $rescoredResults = $rescorer->rescore( $search, $this->namespaces, $results, $this->limit );
 596                 } else {
 597                         // No need to rescore if offset is not 0
 598                         // The exact match must have been returned at position 0
 599                         // if it existed.
 600                         $rescoredResults = $results;
 601                 }
 602
 603                 if ( count( $rescoredResults ) > 0 ) {
 604                         $found = array_search( $rescoredResults[0], $results );
 605                         if ( $found === false ) {
 606                                 // If the first result is not in the previous array it
 607                                 // means that we found a new exact match
 608                                 $exactMatch = SearchSuggestion::fromTitle( 0, Title::newFromText( $rescoredResults[0] ) );
 609                                 $suggestions->prepend( $exactMatch );
 610                                 $suggestions->shrink( $this->limit );
 611                         } else {
 612                                 // if the first result is not the same we need to rescore
 613                                 if ( $found > 0 ) {
 614                                         $suggestions->rescore( $found );
 615                                 }
 616                         }
 617                 }
 618
 619                 return $suggestions;
 620         }
 621
 622         /**
 623          * Simple prefix search for subpages.
 624          * @param string $search
 625          * @return Title[]
 626          */
 627         public function defaultPrefixSearch( $search ) {
 628                 if ( trim( $search ) === '' ) {
 629                         return [];
 630                 }
 631
 632                 $search = $this->normalizeNamespaces( $search );
 633                 return $this->simplePrefixSearch( $search );
 634         }
 635
 636         /**
 637          * Call out to simple search backend.
 638          * Defaults to TitlePrefixSearch.
 639          * @param string $search
 640          * @return Title[]
 641          */
 642         protected function simplePrefixSearch( $search ) {
 643                 // Use default database prefix search
 644                 $backend = new TitlePrefixSearch;
 645                 return $backend->defaultSearchBackend( $this->namespaces, $search, $this->limit, $this->offset );
 646         }
 647
 648         /**
 649          * Make a list of searchable namespaces and their canonical names.
 650          * @deprecated since 1.27; use SearchEngineConfig::searchableNamespaces()
 651          * @return array
 652          */
 653         public static function searchableNamespaces() {
 654                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->searchableNamespaces();
 655         }
 656
 657         /**
 658          * Extract default namespaces to search from the given user's
 659          * settings, returning a list of index numbers.
 660          * @deprecated since 1.27; use SearchEngineConfig::userNamespaces()
 661          * @param user $user
 662          * @return array
 663          */
 664         public static function userNamespaces( $user ) {
 665                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->userNamespaces( $user );
 666         }
 667
 668         /**
 669          * An array of namespaces indexes to be searched by default
 670          * @deprecated since 1.27; use SearchEngineConfig::defaultNamespaces()
 671          * @return array
 672          */
 673         public static function defaultNamespaces() {
 674                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->defaultNamespaces();
 675         }
 676
 677         /**
 678          * Get a list of namespace names useful for showing in tooltips
 679          * and preferences
 680          * @deprecated since 1.27; use SearchEngineConfig::namespacesAsText()
 681          * @param array $namespaces
 682          * @return array
 683          */
 684         public static function namespacesAsText( $namespaces ) {
 685                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->namespacesAsText( $namespaces );
 686         }
 687
 688         /**
 689          * Load up the appropriate search engine class for the currently
 690          * active database backend, and return a configured instance.
 691          * @deprecated since 1.27; Use SearchEngineFactory::create
 692          * @param string $type Type of search backend, if not the default
 693          * @return SearchEngine
 694          */
 695         public static function create( $type = null ) {
 696                 return MediaWikiServices::getInstance()->getSearchEngineFactory()->create( $type );
 697         }
 698
 699         /**
 700          * Return the search engines we support. If only $wgSearchType
 701          * is set, it'll be an array of just that one item.
 702          * @deprecated since 1.27; use SearchEngineConfig::getSearchTypes()
 703          * @return array
 704          */
 705         public static function getSearchTypes() {
 706                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->getSearchTypes();
 707         }
 708
 709         /**
 710          * Get a list of supported profiles.
 711          * Some search engine implementations may expose specific profiles to fine-tune
 712          * its behaviors.
 713          * The profile can be passed as a feature data with setFeatureData( $profileType, $profileName )
 714          * The array returned by this function contains the following keys:
 715          * - name: the profile name to use with setFeatureData
 716          * - desc-message: the i18n description
 717          * - default: set to true if this profile is the default
 718          *
 719          * @since 1.28
 720          * @param string $profileType the type of profiles
 721          * @param User|null $user the user requesting the list of profiles
 722          * @return array|null the list of profiles or null if none available
 723          */
 724         public function getProfiles( $profileType, User $user = null ) {
 725                 return null;
 726         }
 727
 728         /**
 729          * Create a search field definition.
 730          * Specific search engines should override this method to create search fields.
 731          * @param string $name
 732          * @param int    $type One of the types in SearchIndexField::INDEX_TYPE_*
 733          * @return SearchIndexField
 734          * @since 1.28
 735          */
 736         public function makeSearchFieldMapping( $name, $type ) {
 737                 return new NullIndexField();
 738         }
 739
 740         /**
 741          * Get fields for search index
 742          * @since 1.28
 743          * @return SearchIndexField[] Index field definitions for all content handlers
 744          */
 745         public function getSearchIndexFields() {
 746                 $models = ContentHandler::getContentModels();
 747                 $fields = [];
 748                 $seenHandlers = new SplObjectStorage();
 749                 foreach ( $models as $model ) {
 750                         try {
 751                                 $handler = ContentHandler::getForModelID( $model );
 752                         }
 753                         catch ( MWUnknownContentModelException $e ) {
 754                                 // If we can find no handler, ignore it
 755                                 continue;
 756                         }
 757                         // Several models can have the same handler, so avoid processing it repeatedly
 758                         if ( $seenHandlers->contains( $handler ) ) {
 759                                 // We already did this one
 760                                 continue;
 761                         }
 762                         $seenHandlers->attach( $handler );
 763                         $handlerFields = $handler->getFieldsForSearchIndex( $this );
 764                         foreach ( $handlerFields as $fieldName => $fieldData ) {
 765                                 if ( empty( $fields[$fieldName] ) ) {
 766                                         $fields[$fieldName] = $fieldData;
 767                                 } else {
 768                                         // TODO: do we allow some clashes with the same type or reject all of them?
 769                                         $mergeDef = $fields[$fieldName]->merge( $fieldData );
 770                                         if ( !$mergeDef ) {
 771                                                 throw new InvalidArgumentException( "Duplicate field $fieldName for model $model" );
 772                                         }
 773                                         $fields[$fieldName] = $mergeDef;
 774                                 }
 775                         }
 776                 }
 777                 // Hook to allow extensions to produce search mapping fields
 778                 Hooks::run( 'SearchIndexFields', [ &$fields, $this ] );
 779                 return $fields;
 780         }
 781
 782         /**
 783          * Augment search results with extra data.
 784          *
 785          * @param SearchResultSet $resultSet
 786          */
 787         public function augmentSearchResults( SearchResultSet $resultSet ) {
 788                 $setAugmentors = [];
 789                 $rowAugmentors = [];
 790                 Hooks::run( "SearchResultsAugment", [ &$setAugmentors, &$rowAugmentors ] );
 791
 792                 if ( !$setAugmentors && !$rowAugmentors ) {
 793                         // We're done here
 794                         return;
 795                 }
 796
 797                 // Convert row augmentors to set augmentor
 798                 foreach ( $rowAugmentors as $name => $row ) {
 799                         if ( isset( $setAugmentors[$name] ) ) {
 800                                 throw new InvalidArgumentException( "Both row and set augmentors are defined for $name" );
 801                         }
 802                         $setAugmentors[$name] = new PerRowAugmentor( $row );
 803                 }
 804
 805                 foreach ( $setAugmentors as $name => $augmentor ) {
 806                         $data = $augmentor->augmentAll( $resultSet );
 807                         if ( $data ) {
 808                                 $resultSet->setAugmentedData( $name, $data );
 809                         }
 810                 }
 811         }
 812 }
 813
 814 /**
 815  * Dummy class to be used when non-supported Database engine is present.
 816  * @todo FIXME: Dummy class should probably try something at least mildly useful,
 817  * such as a LIKE search through titles.
 818  * @ingroup Search
 819  */
 820 class SearchEngineDummy extends SearchEngine {
 821         // no-op
 822 }