includes/parser/ParserOutput.php

   1 <?php
   2
   3 /**
   4  * Output of the PHP parser.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19  * http://www.gnu.org/copyleft/gpl.html
  20  *
  21  * @file
  22  * @ingroup Parser
  23  */
  24
  25 class ParserOutput extends CacheTime {
  26         /**
  27          * Feature flags to indicate to extensions that MediaWiki core supports and
  28          * uses getText() stateless transforms.
  29          */
  30         const SUPPORTS_STATELESS_TRANSFORMS = 1;
  31         const SUPPORTS_UNWRAP_TRANSFORM = 1;
  32
  33         /**
  34          * @var string|null $mText The output text
  35          */
  36         public $mText = null;
  37
  38         /**
  39          * @var array $mLanguageLinks List of the full text of language links,
  40          *  in the order they appear.
  41          */
  42         public $mLanguageLinks;
  43
  44         /**
  45          * @var array $mCategories Map of category names to sort keys
  46          */
  47         public $mCategories;
  48
  49         /**
  50          * @var array $mIndicators Page status indicators, usually displayed in top-right corner.
  51          */
  52         public $mIndicators = [];
  53
  54         /**
  55          * @var string $mTitleText Title text of the chosen language variant, as HTML.
  56          */
  57         public $mTitleText;
  58
  59         /**
  60          * @var array $mLinks 2-D map of NS/DBK to ID for the links in the document.
  61          *  ID=zero for broken.
  62          */
  63         public $mLinks = [];
  64
  65         /**
  66          * @var array $mTemplates 2-D map of NS/DBK to ID for the template references.
  67          *  ID=zero for broken.
  68          */
  69         public $mTemplates = [];
  70
  71         /**
  72          * @var array $mTemplateIds 2-D map of NS/DBK to rev ID for the template references.
  73          *  ID=zero for broken.
  74          */
  75         public $mTemplateIds = [];
  76
  77         /**
  78          * @var array $mImages DB keys of the images used, in the array key only
  79          */
  80         public $mImages = [];
  81
  82         /**
  83          * @var array $mFileSearchOptions DB keys of the images used mapped to sha1 and MW timestamp.
  84          */
  85         public $mFileSearchOptions = [];
  86
  87         /**
  88          * @var array $mExternalLinks External link URLs, in the key only.
  89          */
  90         public $mExternalLinks = [];
  91
  92         /**
  93          * @var array $mInterwikiLinks 2-D map of prefix/DBK (in keys only)
  94          *  for the inline interwiki links in the document.
  95          */
  96         public $mInterwikiLinks = [];
  97
  98         /**
  99          * @var bool $mNewSection Show a new section link?
 100          */
 101         public $mNewSection = false;
 102
 103         /**
 104          * @var bool $mHideNewSection Hide the new section link?
 105          */
 106         public $mHideNewSection = false;
 107
 108         /**
 109          * @var bool $mNoGallery No gallery on category page? (__NOGALLERY__).
 110          */
 111         public $mNoGallery = false;
 112
 113         /**
 114          * @var array $mHeadItems Items to put in the <head> section
 115          */
 116         public $mHeadItems = [];
 117
 118         /**
 119          * @var array $mModules Modules to be loaded by ResourceLoader
 120          */
 121         public $mModules = [];
 122
 123         /**
 124          * @var array $mModuleStyles Modules of which only the CSSS will be loaded by ResourceLoader.
 125          */
 126         public $mModuleStyles = [];
 127
 128         /**
 129          * @var array $mJsConfigVars JavaScript config variable for mw.config combined with this page.
 130          */
 131         public $mJsConfigVars = [];
 132
 133         /**
 134          * @var array $mOutputHooks Hook tags as per $wgParserOutputHooks.
 135          */
 136         public $mOutputHooks = [];
 137
 138         /**
 139          * @var array $mWarnings Warning text to be returned to the user.
 140          *  Wikitext formatted, in the key only.
 141          */
 142         public $mWarnings = [];
 143
 144         /**
 145          * @var array $mSections Table of contents
 146          */
 147         public $mSections = [];
 148
 149         /**
 150          * @var array $mProperties Name/value pairs to be cached in the DB.
 151          */
 152         public $mProperties = [];
 153
 154         /**
 155          * @var string $mTOCHTML HTML of the TOC.
 156          */
 157         public $mTOCHTML = '';
 158
 159         /**
 160          * @var string $mTimestamp Timestamp of the revision.
 161          */
 162         public $mTimestamp;
 163
 164         /**
 165          * @var bool $mEnableOOUI Whether OOUI should be enabled.
 166          */
 167         public $mEnableOOUI = false;
 168
 169         /**
 170          * @var string $mIndexPolicy 'index' or 'noindex'?  Any other value will result in no change.
 171          */
 172         private $mIndexPolicy = '';
 173
 174         /**
 175          * @var true[] $mAccessedOptions List of ParserOptions (stored in the keys).
 176          */
 177         private $mAccessedOptions = [];
 178
 179         /**
 180          * @var array $mExtensionData extra data used by extensions.
 181          */
 182         private $mExtensionData = [];
 183
 184         /**
 185          * @var array $mLimitReportData Parser limit report data.
 186          */
 187         private $mLimitReportData = [];
 188
 189         /** @var array Parser limit report data for JSON */
 190         private $mLimitReportJSData = [];
 191
 192         /**
 193          * @var array $mParseStartTime Timestamps for getTimeSinceStart().
 194          */
 195         private $mParseStartTime = [];
 196
 197         /**
 198          * @var bool $mPreventClickjacking Whether to emit X-Frame-Options: DENY.
 199          */
 200         private $mPreventClickjacking = false;
 201
 202         /**
 203          * @var array $mFlags Generic flags.
 204          */
 205         private $mFlags = [];
 206
 207         /** @var int|null Assumed rev ID for {{REVISIONID}} if no revision is set */
 208         private $mSpeculativeRevId;
 209
 210         /** @var int|null Assumed rev timestamp for {{REVISIONTIMESTAMP}} if no revision is set */
 211         private $revisionTimestampUsed;
 212
 213         /** string CSS classes to use for the wrapping div, stored in the array keys.
 214          * If no class is given, no wrapper is added.
 215          */
 216         private $mWrapperDivClasses = [];
 217
 218         /** @var int Upper bound of expiry based on parse duration */
 219         private $mMaxAdaptiveExpiry = INF;
 220
 221         const EDITSECTION_REGEX =
 222                 '#<(?:mw:)?editsection page="(.*?)" section="(.*?)"(?:/>|>(.*?)(</(?:mw:)?editsection>))#s';
 223
 224         // finalizeAdaptiveCacheExpiry() uses TTL = MAX( m * PARSE_TIME + b, MIN_AR_TTL)
 225         // Current values imply that m=3933.333333 and b=-333.333333
 226         // See https://www.nngroup.com/articles/website-response-times/
 227         const PARSE_FAST_SEC = 0.100; // perceived "fast" page parse
 228         const PARSE_SLOW_SEC = 1.0; // perceived "slow" page parse
 229         const FAST_AR_TTL = 60; // adaptive TTL for "fast" pages
 230         const SLOW_AR_TTL = 3600; // adaptive TTL for "slow" pages
 231         const MIN_AR_TTL = 15; // min adaptive TTL (for sanity, pool counter, and edit stashing)
 232
 233         /**
 234          * @param string|null $text HTML. Use null to indicate that this ParserOutput contains only
 235          *        meta-data, and the HTML output is undetermined, as opposed to empty. Passing null
 236          *        here causes hasText() to return false.
 237          * @param array $languageLinks
 238          * @param array $categoryLinks
 239          * @param bool $unused
 240          * @param string $titletext
 241          */
 242         public function __construct( $text = '', $languageLinks = [], $categoryLinks = [],
 243                 $unused = false, $titletext = ''
 244         ) {
 245                 $this->mText = $text;
 246                 $this->mLanguageLinks = $languageLinks;
 247                 $this->mCategories = $categoryLinks;
 248                 $this->mTitleText = $titletext;
 249         }
 250
 251         /**
 252          * Returns true if text was passed to the constructor, or set using setText(). Returns false
 253          * if null was passed to the $text parameter of the constructor to indicate that this
 254          * ParserOutput only contains meta-data, and the HTML output is undetermined.
 255          *
 256          * @since 1.32
 257          *
 258          * @return bool Whether this ParserOutput contains rendered text. If this returns false, the
 259          *         ParserOutput contains meta-data only.
 260          */
 261         public function hasText() {
 262                 return ( $this->mText !== null );
 263         }
 264
 265         /**
 266          * Get the cacheable text with <mw:editsection> markers still in it. The
 267          * return value is suitable for writing back via setText() but is not valid
 268          * for display to the user.
 269          *
 270          * @return string
 271          * @since 1.27
 272          */
 273         public function getRawText() {
 274                 if ( $this->mText === null ) {
 275                         throw new LogicException( 'This ParserOutput contains no text!' );
 276                 }
 277
 278                 return $this->mText;
 279         }
 280
 281         /**
 282          * Get the output HTML
 283          *
 284          * @param array $options (since 1.31) Transformations to apply to the HTML
 285          *  - allowTOC: (bool) Show the TOC, assuming there were enough headings
 286          *     to generate one and `__NOTOC__` wasn't used. Default is true,
 287          *     but might be statefully overridden.
 288          *  - enableSectionEditLinks: (bool) Include section edit links, assuming
 289          *     section edit link tokens are present in the HTML. Default is true,
 290          *     but might be statefully overridden.
 291          *  - unwrap: (bool) Return text without a wrapper div. Default is false,
 292          *    meaning a wrapper div will be added if getWrapperDivClass() returns
 293          *    a non-empty string.
 294          *  - wrapperDivClass: (string) Wrap the output in a div and apply the given
 295          *    CSS class to that div. This overrides the output of getWrapperDivClass().
 296          *    Setting this to an empty string has the same effect as 'unwrap' => true.
 297          *  - deduplicateStyles: (bool) When true, which is the default, `<style>`
 298          *    tags with the `data-mw-deduplicate` attribute set are deduplicated by
 299          *    value of the attribute: all but the first will be replaced by `<link
 300          *    rel="mw-deduplicated-inline-style" href="mw-data:..."/>` tags, where
 301          *    the scheme-specific-part of the href is the (percent-encoded) value
 302          *    of the `data-mw-deduplicate` attribute.
 303          * @return string HTML
 304          * @return-taint escaped
 305          */
 306         public function getText( $options = [] ) {
 307                 $options += [
 308                         'allowTOC' => true,
 309                         'enableSectionEditLinks' => true,
 310                         'unwrap' => false,
 311                         'deduplicateStyles' => true,
 312                         'wrapperDivClass' => $this->getWrapperDivClass(),
 313                 ];
 314                 $text = $this->getRawText();
 315
 316                 Hooks::runWithoutAbort( 'ParserOutputPostCacheTransform', [ $this, &$text, &$options ] );
 317
 318                 if ( $options['wrapperDivClass'] !== '' && !$options['unwrap'] ) {
 319                         $text = Html::rawElement( 'div', [ 'class' => $options['wrapperDivClass'] ], $text );
 320                 }
 321
 322                 if ( $options['enableSectionEditLinks'] ) {
 323                         $text = preg_replace_callback(
 324                                 self::EDITSECTION_REGEX,
 325                                 function ( $m ) {
 326                                         $editsectionPage = Title::newFromText( htmlspecialchars_decode( $m[1] ) );
 327                                         $editsectionSection = htmlspecialchars_decode( $m[2] );
 328                                         $editsectionContent = isset( $m[4] ) ? Sanitizer::decodeCharReferences( $m[3] ) : null;
 329
 330                                         if ( !is_object( $editsectionPage ) ) {
 331                                                 throw new MWException( "Bad parser output text." );
 332                                         }
 333
 334                                         $context = RequestContext::getMain();
 335                                         return $context->getSkin()->doEditSectionLink(
 336                                                 $editsectionPage,
 337                                                 $editsectionSection,
 338                                                 $editsectionContent,
 339                                                 $context->getLanguage()
 340                                         );
 341                                 },
 342                                 $text
 343                         );
 344                 } else {
 345                         $text = preg_replace( self::EDITSECTION_REGEX, '', $text );
 346                 }
 347
 348                 if ( $options['allowTOC'] ) {
 349                         $text = str_replace( [ Parser::TOC_START, Parser::TOC_END ], '', $text );
 350                 } else {
 351                         $text = preg_replace(
 352                                 '#' . preg_quote( Parser::TOC_START, '#' ) . '.*?' . preg_quote( Parser::TOC_END, '#' ) . '#s',
 353                                 '',
 354                                 $text
 355                         );
 356                 }
 357
 358                 if ( $options['deduplicateStyles'] ) {
 359                         $seen = [];
 360                         $text = preg_replace_callback(
 361                                 '#<style\s+([^>]*data-mw-deduplicate\s*=[^>]*)>.*?</style>#s',
 362                                 function ( $m ) use ( &$seen ) {
 363                                         $attr = Sanitizer::decodeTagAttributes( $m[1] );
 364                                         if ( !isset( $attr['data-mw-deduplicate'] ) ) {
 365                                                 return $m[0];
 366                                         }
 367
 368                                         $key = $attr['data-mw-deduplicate'];
 369                                         if ( !isset( $seen[$key] ) ) {
 370                                                 $seen[$key] = true;
 371                                                 return $m[0];
 372                                         }
 373
 374                                         // We were going to use an empty <style> here, but there
 375                                         // was concern that would be too much overhead for browsers.
 376                                         // So let's hope a <link> with a non-standard rel and href isn't
 377                                         // going to be misinterpreted or mangled by any subsequent processing.
 378                                         return Html::element( 'link', [
 379                                                 'rel' => 'mw-deduplicated-inline-style',
 380                                                 'href' => "mw-data:" . wfUrlencode( $key ),
 381                                         ] );
 382                                 },
 383                                 $text
 384                         );
 385                 }
 386
 387                 // Hydrate slot section header placeholders generated by RevisionRenderer.
 388                 $text = preg_replace_callback(
 389                         '#<mw:slotheader>(.*?)</mw:slotheader>#',
 390                         function ( $m ) {
 391                                 $role = htmlspecialchars_decode( $m[1] );
 392                                 // TODO: map to message, using the interface language. Set lang="xyz" accordingly.
 393                                 $headerText = $role;
 394                                 return $headerText;
 395                         },
 396                         $text
 397                 );
 398                 return $text;
 399         }
 400
 401         /**
 402          * Add a CSS class to use for the wrapping div. If no class is given, no wrapper is added.
 403          *
 404          * @param string $class
 405          */
 406         public function addWrapperDivClass( $class ) {
 407                 $this->mWrapperDivClasses[$class] = true;
 408         }
 409
 410         /**
 411          * Clears the CSS class to use for the wrapping div, effectively disabling the wrapper div
 412          * until addWrapperDivClass() is called.
 413          */
 414         public function clearWrapperDivClass() {
 415                 $this->mWrapperDivClasses = [];
 416         }
 417
 418         /**
 419          * Returns the class (or classes) to be used with the wrapper div for this otuput.
 420          * If there is no wrapper class given, no wrapper div should be added.
 421          * The wrapper div is added automatically by getText().
 422          *
 423          * @return string
 424          */
 425         public function getWrapperDivClass() {
 426                 return implode( ' ', array_keys( $this->mWrapperDivClasses ) );
 427         }
 428
 429         /**
 430          * @param int $id
 431          * @since 1.28
 432          */
 433         public function setSpeculativeRevIdUsed( $id ) {
 434                 $this->mSpeculativeRevId = $id;
 435         }
 436
 437         /**
 438          * @return int|null
 439          * @since 1.28
 440          */
 441         public function getSpeculativeRevIdUsed() {
 442                 return $this->mSpeculativeRevId;
 443         }
 444
 445         /**
 446          * @param string $timestamp TS_MW timestamp
 447          * @since 1.34
 448          */
 449         public function setRevisionTimestampUsed( $timestamp ) {
 450                 $this->revisionTimestampUsed = $timestamp;
 451         }
 452
 453         /**
 454          * @return string|null TS_MW timestamp or null if not used
 455          * @since 1.34
 456          */
 457         public function getRevisionTimestampUsed() {
 458                 return $this->revisionTimestampUsed;
 459         }
 460
 461         public function &getLanguageLinks() {
 462                 return $this->mLanguageLinks;
 463         }
 464
 465         public function getInterwikiLinks() {
 466                 return $this->mInterwikiLinks;
 467         }
 468
 469         public function getCategoryLinks() {
 470                 return array_keys( $this->mCategories );
 471         }
 472
 473         public function &getCategories() {
 474                 return $this->mCategories;
 475         }
 476
 477         /**
 478          * @return array
 479          * @since 1.25
 480          */
 481         public function getIndicators() {
 482                 return $this->mIndicators;
 483         }
 484
 485         public function getTitleText() {
 486                 return $this->mTitleText;
 487         }
 488
 489         public function getSections() {
 490                 return $this->mSections;
 491         }
 492
 493         public function &getLinks() {
 494                 return $this->mLinks;
 495         }
 496
 497         public function &getTemplates() {
 498                 return $this->mTemplates;
 499         }
 500
 501         public function &getTemplateIds() {
 502                 return $this->mTemplateIds;
 503         }
 504
 505         public function &getImages() {
 506                 return $this->mImages;
 507         }
 508
 509         public function &getFileSearchOptions() {
 510                 return $this->mFileSearchOptions;
 511         }
 512
 513         public function &getExternalLinks() {
 514                 return $this->mExternalLinks;
 515         }
 516
 517         public function setNoGallery( $value ) {
 518                 $this->mNoGallery = (bool)$value;
 519         }
 520
 521         public function getNoGallery() {
 522                 return $this->mNoGallery;
 523         }
 524
 525         public function getHeadItems() {
 526                 return $this->mHeadItems;
 527         }
 528
 529         public function getModules() {
 530                 return $this->mModules;
 531         }
 532
 533         public function getModuleStyles() {
 534                 return $this->mModuleStyles;
 535         }
 536
 537         /**
 538          * @return array
 539          * @since 1.23
 540          */
 541         public function getJsConfigVars() {
 542                 return $this->mJsConfigVars;
 543         }
 544
 545         public function getOutputHooks() {
 546                 return (array)$this->mOutputHooks;
 547         }
 548
 549         public function getWarnings() {
 550                 return array_keys( $this->mWarnings );
 551         }
 552
 553         public function getIndexPolicy() {
 554                 return $this->mIndexPolicy;
 555         }
 556
 557         public function getTOCHTML() {
 558                 return $this->mTOCHTML;
 559         }
 560
 561         /**
 562          * @return string|null TS_MW timestamp of the revision content
 563          */
 564         public function getTimestamp() {
 565                 return $this->mTimestamp;
 566         }
 567
 568         public function getLimitReportData() {
 569                 return $this->mLimitReportData;
 570         }
 571
 572         public function getLimitReportJSData() {
 573                 return $this->mLimitReportJSData;
 574         }
 575
 576         public function getEnableOOUI() {
 577                 return $this->mEnableOOUI;
 578         }
 579
 580         public function setText( $text ) {
 581                 return wfSetVar( $this->mText, $text );
 582         }
 583
 584         public function setLanguageLinks( $ll ) {
 585                 return wfSetVar( $this->mLanguageLinks, $ll );
 586         }
 587
 588         public function setCategoryLinks( $cl ) {
 589                 return wfSetVar( $this->mCategories, $cl );
 590         }
 591
 592         public function setTitleText( $t ) {
 593                 return wfSetVar( $this->mTitleText, $t );
 594         }
 595
 596         public function setSections( $toc ) {
 597                 return wfSetVar( $this->mSections, $toc );
 598         }
 599
 600         public function setIndexPolicy( $policy ) {
 601                 return wfSetVar( $this->mIndexPolicy, $policy );
 602         }
 603
 604         public function setTOCHTML( $tochtml ) {
 605                 return wfSetVar( $this->mTOCHTML, $tochtml );
 606         }
 607
 608         public function setTimestamp( $timestamp ) {
 609                 return wfSetVar( $this->mTimestamp, $timestamp );
 610         }
 611
 612         public function addCategory( $c, $sort ) {
 613                 $this->mCategories[$c] = $sort;
 614         }
 615
 616         /**
 617          * @param string $id
 618          * @param string $content
 619          * @since 1.25
 620          */
 621         public function setIndicator( $id, $content ) {
 622                 $this->mIndicators[$id] = $content;
 623         }
 624
 625         /**
 626          * Enables OOUI, if true, in any OutputPage instance this ParserOutput
 627          * object is added to.
 628          *
 629          * @since 1.26
 630          * @param bool $enable If OOUI should be enabled or not
 631          */
 632         public function setEnableOOUI( $enable = false ) {
 633                 $this->mEnableOOUI = $enable;
 634         }
 635
 636         public function addLanguageLink( $t ) {
 637                 $this->mLanguageLinks[] = $t;
 638         }
 639
 640         public function addWarning( $s ) {
 641                 $this->mWarnings[$s] = 1;
 642         }
 643
 644         public function addOutputHook( $hook, $data = false ) {
 645                 $this->mOutputHooks[] = [ $hook, $data ];
 646         }
 647
 648         public function setNewSection( $value ) {
 649                 $this->mNewSection = (bool)$value;
 650         }
 651
 652         public function hideNewSection( $value ) {
 653                 $this->mHideNewSection = (bool)$value;
 654         }
 655
 656         public function getHideNewSection() {
 657                 return (bool)$this->mHideNewSection;
 658         }
 659
 660         public function getNewSection() {
 661                 return (bool)$this->mNewSection;
 662         }
 663
 664         /**
 665          * Checks, if a url is pointing to the own server
 666          *
 667          * @param string $internal The server to check against
 668          * @param string $url The url to check
 669          * @return bool
 670          */
 671         public static function isLinkInternal( $internal, $url ) {
 672                 return (bool)preg_match( '/^' .
 673                         # If server is proto relative, check also for http/https links
 674                         ( substr( $internal, 0, 2 ) === '//' ? '(?:https?:)?' : '' ) .
 675                         preg_quote( $internal, '/' ) .
 676                         # check for query/path/anchor or end of link in each case
 677                         '(?:[\?\/\#]|$)/i',
 678                         $url
 679                 );
 680         }
 681
 682         public function addExternalLink( $url ) {
 683                 # We don't register links pointing to our own server, unless... :-)
 684                 global $wgServer, $wgRegisterInternalExternals;
 685
 686                 # Replace unnecessary URL escape codes with the referenced character
 687                 # This prevents spammers from hiding links from the filters
 688                 $url = Parser::normalizeLinkUrl( $url );
 689
 690                 $registerExternalLink = true;
 691                 if ( !$wgRegisterInternalExternals ) {
 692                         $registerExternalLink = !self::isLinkInternal( $wgServer, $url );
 693                 }
 694                 if ( $registerExternalLink ) {
 695                         $this->mExternalLinks[$url] = 1;
 696                 }
 697         }
 698
 699         /**
 700          * Record a local or interwiki inline link for saving in future link tables.
 701          *
 702          * @param Title $title
 703          * @param int|null $id Optional known page_id so we can skip the lookup
 704          */
 705         public function addLink( Title $title, $id = null ) {
 706                 if ( $title->isExternal() ) {
 707                         // Don't record interwikis in pagelinks
 708                         $this->addInterwikiLink( $title );
 709                         return;
 710                 }
 711                 $ns = $title->getNamespace();
 712                 $dbk = $title->getDBkey();
 713                 if ( $ns == NS_MEDIA ) {
 714                         // Normalize this pseudo-alias if it makes it down here...
 715                         $ns = NS_FILE;
 716                 } elseif ( $ns == NS_SPECIAL ) {
 717                         // We don't record Special: links currently
 718                         // It might actually be wise to, but we'd need to do some normalization.
 719                         return;
 720                 } elseif ( $dbk === '' ) {
 721                         // Don't record self links -  [[#Foo]]
 722                         return;
 723                 }
 724                 if ( !isset( $this->mLinks[$ns] ) ) {
 725                         $this->mLinks[$ns] = [];
 726                 }
 727                 if ( is_null( $id ) ) {
 728                         $id = $title->getArticleID();
 729                 }
 730                 $this->mLinks[$ns][$dbk] = $id;
 731         }
 732
 733         /**
 734          * Register a file dependency for this output
 735          * @param string $name Title dbKey
 736          * @param string|false|null $timestamp MW timestamp of file creation (or false if non-existing)
 737          * @param string|false|null $sha1 Base 36 SHA-1 of file (or false if non-existing)
 738          */
 739         public function addImage( $name, $timestamp = null, $sha1 = null ) {
 740                 $this->mImages[$name] = 1;
 741                 if ( $timestamp !== null && $sha1 !== null ) {
 742                         $this->mFileSearchOptions[$name] = [ 'time' => $timestamp, 'sha1' => $sha1 ];
 743                 }
 744         }
 745
 746         /**
 747          * Register a template dependency for this output
 748          * @param Title $title
 749          * @param int $page_id
 750          * @param int $rev_id
 751          */
 752         public function addTemplate( $title, $page_id, $rev_id ) {
 753                 $ns = $title->getNamespace();
 754                 $dbk = $title->getDBkey();
 755                 if ( !isset( $this->mTemplates[$ns] ) ) {
 756                         $this->mTemplates[$ns] = [];
 757                 }
 758                 $this->mTemplates[$ns][$dbk] = $page_id;
 759                 if ( !isset( $this->mTemplateIds[$ns] ) ) {
 760                         $this->mTemplateIds[$ns] = [];
 761                 }
 762                 $this->mTemplateIds[$ns][$dbk] = $rev_id; // For versioning
 763         }
 764
 765         /**
 766          * @param Title $title Title object, must be an interwiki link
 767          * @throws MWException If given invalid input
 768          */
 769         public function addInterwikiLink( $title ) {
 770                 if ( !$title->isExternal() ) {
 771                         throw new MWException( 'Non-interwiki link passed, internal parser error.' );
 772                 }
 773                 $prefix = $title->getInterwiki();
 774                 if ( !isset( $this->mInterwikiLinks[$prefix] ) ) {
 775                         $this->mInterwikiLinks[$prefix] = [];
 776                 }
 777                 $this->mInterwikiLinks[$prefix][$title->getDBkey()] = 1;
 778         }
 779
 780         /**
 781          * Add some text to the "<head>".
 782          * If $tag is set, the section with that tag will only be included once
 783          * in a given page.
 784          * @param string $section
 785          * @param string|bool $tag
 786          */
 787         public function addHeadItem( $section, $tag = false ) {
 788                 if ( $tag !== false ) {
 789                         $this->mHeadItems[$tag] = $section;
 790                 } else {
 791                         $this->mHeadItems[] = $section;
 792                 }
 793         }
 794
 795         /**
 796          * @see OutputPage::addModules
 797          */
 798         public function addModules( $modules ) {
 799                 $this->mModules = array_merge( $this->mModules, (array)$modules );
 800         }
 801
 802         /**
 803          * @see OutputPage::addModuleStyles
 804          */
 805         public function addModuleStyles( $modules ) {
 806                 $this->mModuleStyles = array_merge( $this->mModuleStyles, (array)$modules );
 807         }
 808
 809         /**
 810          * Add one or more variables to be set in mw.config in JavaScript.
 811          *
 812          * @param string|array $keys Key or array of key/value pairs.
 813          * @param mixed|null $value [optional] Value of the configuration variable.
 814          * @since 1.23
 815          */
 816         public function addJsConfigVars( $keys, $value = null ) {
 817                 if ( is_array( $keys ) ) {
 818                         foreach ( $keys as $key => $value ) {
 819                                 $this->mJsConfigVars[$key] = $value;
 820                         }
 821                         return;
 822                 }
 823
 824                 $this->mJsConfigVars[$keys] = $value;
 825         }
 826
 827         /**
 828          * Copy items from the OutputPage object into this one
 829          *
 830          * @param OutputPage $out
 831          */
 832         public function addOutputPageMetadata( OutputPage $out ) {
 833                 $this->addModules( $out->getModules() );
 834                 $this->addModuleStyles( $out->getModuleStyles() );
 835                 $this->addJsConfigVars( $out->getJsConfigVars() );
 836
 837                 $this->mHeadItems = array_merge( $this->mHeadItems, $out->getHeadItemsArray() );
 838                 $this->mPreventClickjacking = $this->mPreventClickjacking || $out->getPreventClickjacking();
 839         }
 840
 841         /**
 842          * Add a tracking category, getting the title from a system message,
 843          * or print a debug message if the title is invalid.
 844          *
 845          * Any message used with this function should be registered so it will
 846          * show up on Special:TrackingCategories. Core messages should be added
 847          * to SpecialTrackingCategories::$coreTrackingCategories, and extensions
 848          * should add to "TrackingCategories" in their extension.json.
 849          *
 850          * @todo Migrate some code to TrackingCategories
 851          *
 852          * @param string $msg Message key
 853          * @param Title $title title of the page which is being tracked
 854          * @return bool Whether the addition was successful
 855          * @since 1.25
 856          */
 857         public function addTrackingCategory( $msg, $title ) {
 858                 if ( $title->isSpecialPage() ) {
 859                         wfDebug( __METHOD__ . ": Not adding tracking category $msg to special page!\n" );
 860                         return false;
 861                 }
 862
 863                 // Important to parse with correct title (T33469)
 864                 $cat = wfMessage( $msg )
 865                         ->title( $title )
 866                         ->inContentLanguage()
 867                         ->text();
 868
 869                 # Allow tracking categories to be disabled by setting them to "-"
 870                 if ( $cat === '-' ) {
 871                         return false;
 872                 }
 873
 874                 $containerCategory = Title::makeTitleSafe( NS_CATEGORY, $cat );
 875                 if ( $containerCategory ) {
 876                         $this->addCategory( $containerCategory->getDBkey(), $this->getProperty( 'defaultsort' ) ?: '' );
 877                         return true;
 878                 } else {
 879                         wfDebug( __METHOD__ . ": [[MediaWiki:$msg]] is not a valid title!\n" );
 880                         return false;
 881                 }
 882         }
 883
 884         /**
 885          * Override the title to be used for display
 886          *
 887          * @note this is assumed to have been validated
 888          * (check equal normalisation, etc.)
 889          *
 890          * @note this is expected to be safe HTML,
 891          * ready to be served to the client.
 892          *
 893          * @param string $text Desired title text
 894          */
 895         public function setDisplayTitle( $text ) {
 896                 $this->setTitleText( $text );
 897                 $this->setProperty( 'displaytitle', $text );
 898         }
 899
 900         /**
 901          * Get the title to be used for display.
 902          *
 903          * As per the contract of setDisplayTitle(), this is safe HTML,
 904          * ready to be served to the client.
 905          *
 906          * @return string HTML
 907          */
 908         public function getDisplayTitle() {
 909                 $t = $this->getTitleText();
 910                 if ( $t === '' ) {
 911                         return false;
 912                 }
 913                 return $t;
 914         }
 915
 916         /**
 917          * Fairly generic flag setter thingy.
 918          * @param string $flag
 919          */
 920         public function setFlag( $flag ) {
 921                 $this->mFlags[$flag] = true;
 922         }
 923
 924         public function getFlag( $flag ) {
 925                 return isset( $this->mFlags[$flag] );
 926         }
 927
 928         /**
 929          * Set a property to be stored in the page_props database table.
 930          *
 931          * page_props is a key value store indexed by the page ID. This allows
 932          * the parser to set a property on a page which can then be quickly
 933          * retrieved given the page ID or via a DB join when given the page
 934          * title.
 935          *
 936          * Since 1.23, page_props are also indexed by numeric value, to allow
 937          * for efficient "top k" queries of pages wrt a given property.
 938          *
 939          * setProperty() is thus used to propagate properties from the parsed
 940          * page to request contexts other than a page view of the currently parsed
 941          * article.
 942          *
 943          * Some applications examples:
 944          *
 945          *   * To implement hidden categories, hiding pages from category listings
 946          *     by storing a property.
 947          *
 948          *   * Overriding the displayed article title (ParserOutput::setDisplayTitle()).
 949          *
 950          *   * To implement image tagging, for example displaying an icon on an
 951          *     image thumbnail to indicate that it is listed for deletion on
 952          *     Wikimedia Commons.
 953          *     This is not actually implemented, yet but would be pretty cool.
 954          *
 955          * @note Do not use setProperty() to set a property which is only used
 956          * in a context where the ParserOutput object itself is already available,
 957          * for example a normal page view. There is no need to save such a property
 958          * in the database since the text is already parsed. You can just hook
 959          * OutputPageParserOutput and get your data out of the ParserOutput object.
 960          *
 961          * If you are writing an extension where you want to set a property in the
 962          * parser which is used by an OutputPageParserOutput hook, you have to
 963          * associate the extension data directly with the ParserOutput object.
 964          * Since MediaWiki 1.21, you can use setExtensionData() to do this:
 965          *
 966          * @par Example:
 967          * @code
 968          *    $parser->getOutput()->setExtensionData( 'my_ext_foo', '...' );
 969          * @endcode
 970          *
 971          * And then later, in OutputPageParserOutput or similar:
 972          *
 973          * @par Example:
 974          * @code
 975          *    $output->getExtensionData( 'my_ext_foo' );
 976          * @endcode
 977          *
 978          * In MediaWiki 1.20 and older, you have to use a custom member variable
 979          * within the ParserOutput object:
 980          *
 981          * @par Example:
 982          * @code
 983          *    $parser->getOutput()->my_ext_foo = '...';
 984          * @endcode
 985          * @param string $name
 986          * @param mixed $value
 987          */
 988         public function setProperty( $name, $value ) {
 989                 $this->mProperties[$name] = $value;
 990         }
 991
 992         /**
 993          * @param string $name The property name to look up.
 994          *
 995          * @return mixed|bool The value previously set using setProperty(). False if null or no value
 996          * was set for the given property name.
 997          *
 998          * @note You need to use getProperties() to check for boolean and null properties.
 999          */
1000         public function getProperty( $name ) {
1001                 return $this->mProperties[$name] ?? false;
1002         }
1003
1004         public function unsetProperty( $name ) {
1005                 unset( $this->mProperties[$name] );
1006         }
1007
1008         public function getProperties() {
1009                 if ( !isset( $this->mProperties ) ) {
1010                         $this->mProperties = [];
1011                 }
1012                 return $this->mProperties;
1013         }
1014
1015         /**
1016          * Returns the options from its ParserOptions which have been taken
1017          * into account to produce this output.
1018          * @return string[]
1019          */
1020         public function getUsedOptions() {
1021                 if ( !isset( $this->mAccessedOptions ) ) {
1022                         return [];
1023                 }
1024                 return array_keys( $this->mAccessedOptions );
1025         }
1026
1027         /**
1028          * Tags a parser option for use in the cache key for this parser output.
1029          * Registered as a watcher at ParserOptions::registerWatcher() by Parser::clearState().
1030          * The information gathered here is available via getUsedOptions(),
1031          * and is used by ParserCache::save().
1032          *
1033          * @see ParserCache::getKey
1034          * @see ParserCache::save
1035          * @see ParserOptions::addExtraKey
1036          * @see ParserOptions::optionsHash
1037          * @param string $option
1038          */
1039         public function recordOption( $option ) {
1040                 $this->mAccessedOptions[$option] = true;
1041         }
1042
1043         /**
1044          * Attaches arbitrary data to this ParserObject. This can be used to store some information in
1045          * the ParserOutput object for later use during page output. The data will be cached along with
1046          * the ParserOutput object, but unlike data set using setProperty(), it is not recorded in the
1047          * database.
1048          *
1049          * This method is provided to overcome the unsafe practice of attaching extra information to a
1050          * ParserObject by directly assigning member variables.
1051          *
1052          * To use setExtensionData() to pass extension information from a hook inside the parser to a
1053          * hook in the page output, use this in the parser hook:
1054          *
1055          * @par Example:
1056          * @code
1057          *    $parser->getOutput()->setExtensionData( 'my_ext_foo', '...' );
1058          * @endcode
1059          *
1060          * And then later, in OutputPageParserOutput or similar:
1061          *
1062          * @par Example:
1063          * @code
1064          *    $output->getExtensionData( 'my_ext_foo' );
1065          * @endcode
1066          *
1067          * In MediaWiki 1.20 and older, you have to use a custom member variable
1068          * within the ParserOutput object:
1069          *
1070          * @par Example:
1071          * @code
1072          *    $parser->getOutput()->my_ext_foo = '...';
1073          * @endcode
1074          *
1075          * @since 1.21
1076          *
1077          * @param string $key The key for accessing the data. Extensions should take care to avoid
1078          *   conflicts in naming keys. It is suggested to use the extension's name as a prefix.
1079          *
1080          * @param mixed $value The value to set. Setting a value to null is equivalent to removing
1081          *   the value.
1082          */
1083         public function setExtensionData( $key, $value ) {
1084                 if ( $value === null ) {
1085                         unset( $this->mExtensionData[$key] );
1086                 } else {
1087                         $this->mExtensionData[$key] = $value;
1088                 }
1089         }
1090
1091         /**
1092          * Gets extensions data previously attached to this ParserOutput using setExtensionData().
1093          * Typically, such data would be set while parsing the page, e.g. by a parser function.
1094          *
1095          * @since 1.21
1096          *
1097          * @param string $key The key to look up.
1098          *
1099          * @return mixed|null The value previously set for the given key using setExtensionData()
1100          *         or null if no value was set for this key.
1101          */
1102         public function getExtensionData( $key ) {
1103                 return $this->mExtensionData[$key] ?? null;
1104         }
1105
1106         private static function getTimes( $clock = null ) {
1107                 $ret = [];
1108                 if ( !$clock || $clock === 'wall' ) {
1109                         $ret['wall'] = microtime( true );
1110                 }
1111                 if ( !$clock || $clock === 'cpu' ) {
1112                         $ru = wfGetRusage();
1113                         if ( $ru ) {
1114                                 $ret['cpu'] = $ru['ru_utime.tv_sec'] + $ru['ru_utime.tv_usec'] / 1e6;
1115                                 $ret['cpu'] += $ru['ru_stime.tv_sec'] + $ru['ru_stime.tv_usec'] / 1e6;
1116                         }
1117                 }
1118                 return $ret;
1119         }
1120
1121         /**
1122          * Resets the parse start timestamps for future calls to getTimeSinceStart()
1123          * @since 1.22
1124          */
1125         public function resetParseStartTime() {
1126                 $this->mParseStartTime = self::getTimes();
1127         }
1128
1129         /**
1130          * Returns the time since resetParseStartTime() was last called
1131          *
1132          * Clocks available are:
1133          *  - wall: Wall clock time
1134          *  - cpu: CPU time (requires getrusage)
1135          *
1136          * @since 1.22
1137          * @param string $clock
1138          * @return float|null
1139          */
1140         public function getTimeSinceStart( $clock ) {
1141                 if ( !isset( $this->mParseStartTime[$clock] ) ) {
1142                         return null;
1143                 }
1144
1145                 $end = self::getTimes( $clock );
1146                 return $end[$clock] - $this->mParseStartTime[$clock];
1147         }
1148
1149         /**
1150          * Sets parser limit report data for a key
1151          *
1152          * The key is used as the prefix for various messages used for formatting:
1153          *  - $key: The label for the field in the limit report
1154          *  - $key-value-text: Message used to format the value in the "NewPP limit
1155          *      report" HTML comment. If missing, uses $key-format.
1156          *  - $key-value-html: Message used to format the value in the preview
1157          *      limit report table. If missing, uses $key-format.
1158          *  - $key-value: Message used to format the value. If missing, uses "$1".
1159          *
1160          * Note that all values are interpreted as wikitext, and so should be
1161          * encoded with htmlspecialchars() as necessary, but should avoid complex
1162          * HTML for sanity of display in the "NewPP limit report" comment.
1163          *
1164          * @since 1.22
1165          * @param string $key Message key
1166          * @param mixed $value Appropriate for Message::params()
1167          */
1168         public function setLimitReportData( $key, $value ) {
1169                 $this->mLimitReportData[$key] = $value;
1170
1171                 if ( is_array( $value ) ) {
1172                         if ( array_keys( $value ) === [ 0, 1 ]
1173                                 && is_numeric( $value[0] )
1174                                 && is_numeric( $value[1] )
1175                         ) {
1176                                 $data = [ 'value' => $value[0], 'limit' => $value[1] ];
1177                         } else {
1178                                 $data = $value;
1179                         }
1180                 } else {
1181                         $data = $value;
1182                 }
1183
1184                 if ( strpos( $key, '-' ) ) {
1185                         list( $ns, $name ) = explode( '-', $key, 2 );
1186                         $this->mLimitReportJSData[$ns][$name] = $data;
1187                 } else {
1188                         $this->mLimitReportJSData[$key] = $data;
1189                 }
1190         }
1191
1192         /**
1193          * Check whether the cache TTL was lowered due to dynamic content
1194          *
1195          * When content is determined by more than hard state (e.g. page edits),
1196          * such as template/file transclusions based on the current timestamp or
1197          * extension tags that generate lists based on queries, this return true.
1198          *
1199          * @return bool
1200          * @since 1.25
1201          */
1202         public function hasDynamicContent() {
1203                 global $wgParserCacheExpireTime;
1204
1205                 return $this->getCacheExpiry() < $wgParserCacheExpireTime;
1206         }
1207
1208         /**
1209          * Get or set the prevent-clickjacking flag
1210          *
1211          * @since 1.24
1212          * @param bool|null $flag New flag value, or null to leave it unchanged
1213          * @return bool Old flag value
1214          */
1215         public function preventClickjacking( $flag = null ) {
1216                 return wfSetVar( $this->mPreventClickjacking, $flag );
1217         }
1218
1219         /**
1220          * Lower the runtime adaptive TTL to at most this value
1221          *
1222          * @param int $ttl
1223          * @since 1.28
1224          */
1225         public function updateRuntimeAdaptiveExpiry( $ttl ) {
1226                 $this->mMaxAdaptiveExpiry = min( $ttl, $this->mMaxAdaptiveExpiry );
1227                 $this->updateCacheExpiry( $ttl );
1228         }
1229
1230         /**
1231          * Call this when parsing is done to lower the TTL based on low parse times
1232          *
1233          * @since 1.28
1234          */
1235         public function finalizeAdaptiveCacheExpiry() {
1236                 if ( is_infinite( $this->mMaxAdaptiveExpiry ) ) {
1237                         return; // not set
1238                 }
1239
1240                 $runtime = $this->getTimeSinceStart( 'wall' );
1241                 if ( is_float( $runtime ) ) {
1242                         $slope = ( self::SLOW_AR_TTL - self::FAST_AR_TTL )
1243                                 / ( self::PARSE_SLOW_SEC - self::PARSE_FAST_SEC );
1244                         // SLOW_AR_TTL = PARSE_SLOW_SEC * $slope + $point
1245                         $point = self::SLOW_AR_TTL - self::PARSE_SLOW_SEC * $slope;
1246
1247                         $adaptiveTTL = min(
1248                                 max( $slope * $runtime + $point, self::MIN_AR_TTL ),
1249                                 $this->mMaxAdaptiveExpiry
1250                         );
1251                         $this->updateCacheExpiry( $adaptiveTTL );
1252                 }
1253         }
1254
1255         public function __sleep() {
1256                 return array_diff(
1257                         array_keys( get_object_vars( $this ) ),
1258                         [ 'mParseStartTime' ]
1259                 );
1260         }
1261
1262         /**
1263          * Merges internal metadata such as flags, accessed options, and profiling info
1264          * from $source into this ParserOutput. This should be used whenever the state of $source
1265          * has any impact on the state of this ParserOutput.
1266          *
1267          * @param ParserOutput $source
1268          */
1269         public function mergeInternalMetaDataFrom( ParserOutput $source ) {
1270                 $this->mOutputHooks = self::mergeList( $this->mOutputHooks, $source->getOutputHooks() );
1271                 $this->mWarnings = self::mergeMap( $this->mWarnings, $source->mWarnings ); // don't use getter
1272                 $this->mTimestamp = $this->useMaxValue( $this->mTimestamp, $source->getTimestamp() );
1273
1274                 if ( $this->mSpeculativeRevId && $source->mSpeculativeRevId
1275                         && $this->mSpeculativeRevId !== $source->mSpeculativeRevId
1276                 ) {
1277                         wfLogWarning(
1278                                 'Inconsistent speculative revision ID encountered while merging parser output!'
1279                         );
1280                 }
1281
1282                 $this->mSpeculativeRevId = $this->useMaxValue(
1283                         $this->mSpeculativeRevId,
1284                         $source->getSpeculativeRevIdUsed()
1285                 );
1286                 $this->mParseStartTime = $this->useEachMinValue(
1287                         $this->mParseStartTime,
1288                         $source->mParseStartTime
1289                 );
1290
1291                 $this->mFlags = self::mergeMap( $this->mFlags, $source->mFlags );
1292                 $this->mAccessedOptions = self::mergeMap( $this->mAccessedOptions, $source->mAccessedOptions );
1293
1294                 // TODO: maintain per-slot limit reports!
1295                 if ( empty( $this->mLimitReportData ) ) {
1296                         $this->mLimitReportData = $source->mLimitReportData;
1297                 }
1298                 if ( empty( $this->mLimitReportJSData ) ) {
1299                         $this->mLimitReportJSData = $source->mLimitReportJSData;
1300                 }
1301         }
1302
1303         /**
1304          * Merges HTML metadata such as head items, JS config vars, and HTTP cache control info
1305          * from $source into this ParserOutput. This should be used whenever the HTML in $source
1306          * has been somehow mered into the HTML of this ParserOutput.
1307          *
1308          * @param ParserOutput $source
1309          */
1310         public function mergeHtmlMetaDataFrom( ParserOutput $source ) {
1311                 // HTML and HTTP
1312                 $this->mHeadItems = self::mergeMixedList( $this->mHeadItems, $source->getHeadItems() );
1313                 $this->mModules = self::mergeList( $this->mModules, $source->getModules() );
1314                 $this->mModuleStyles = self::mergeList( $this->mModuleStyles, $source->getModuleStyles() );
1315                 $this->mJsConfigVars = self::mergeMap( $this->mJsConfigVars, $source->getJsConfigVars() );
1316                 $this->mMaxAdaptiveExpiry = min( $this->mMaxAdaptiveExpiry, $source->mMaxAdaptiveExpiry );
1317
1318                 // "noindex" always wins!
1319                 if ( $this->mIndexPolicy === 'noindex' || $source->mIndexPolicy === 'noindex' ) {
1320                         $this->mIndexPolicy = 'noindex';
1321                 } elseif ( $this->mIndexPolicy !== 'index' ) {
1322                         $this->mIndexPolicy = $source->mIndexPolicy;
1323                 }
1324
1325                 // Skin control
1326                 $this->mNewSection = $this->mNewSection || $source->getNewSection();
1327                 $this->mHideNewSection = $this->mHideNewSection || $source->getHideNewSection();
1328                 $this->mNoGallery = $this->mNoGallery || $source->getNoGallery();
1329                 $this->mEnableOOUI = $this->mEnableOOUI || $source->getEnableOOUI();
1330                 $this->mPreventClickjacking = $this->mPreventClickjacking || $source->preventClickjacking();
1331
1332                 // TODO: we'll have to be smarter about this!
1333                 $this->mSections = array_merge( $this->mSections, $source->getSections() );
1334                 $this->mTOCHTML .= $source->mTOCHTML;
1335
1336                 // XXX: we don't want to concatenate title text, so first write wins.
1337                 // We should use the first *modified* title text, but we don't have the original to check.
1338                 if ( $this->mTitleText === null || $this->mTitleText === '' ) {
1339                         $this->mTitleText = $source->mTitleText;
1340                 }
1341
1342                 // class names are stored in array keys
1343                 $this->mWrapperDivClasses = self::mergeMap(
1344                         $this->mWrapperDivClasses,
1345                         $source->mWrapperDivClasses
1346                 );
1347
1348                 // NOTE: last write wins, same as within one ParserOutput
1349                 $this->mIndicators = self::mergeMap( $this->mIndicators, $source->getIndicators() );
1350
1351                 // NOTE: include extension data in "tracking meta data" as well as "html meta data"!
1352                 // TODO: add a $mergeStrategy parameter to setExtensionData to allow different
1353                 // kinds of extension data to be merged in different ways.
1354                 $this->mExtensionData = self::mergeMap(
1355                         $this->mExtensionData,
1356                         $source->mExtensionData
1357                 );
1358         }
1359
1360         /**
1361          * Merges dependency tracking metadata such as backlinks, images used, and extension data
1362          * from $source into this ParserOutput. This allows dependency tracking to be done for the
1363          * combined output of multiple content slots.
1364          *
1365          * @param ParserOutput $source
1366          */
1367         public function mergeTrackingMetaDataFrom( ParserOutput $source ) {
1368                 $this->mLanguageLinks = self::mergeList( $this->mLanguageLinks, $source->getLanguageLinks() );
1369                 $this->mCategories = self::mergeMap( $this->mCategories, $source->getCategories() );
1370                 $this->mLinks = self::merge2D( $this->mLinks, $source->getLinks() );
1371                 $this->mTemplates = self::merge2D( $this->mTemplates, $source->getTemplates() );
1372                 $this->mTemplateIds = self::merge2D( $this->mTemplateIds, $source->getTemplateIds() );
1373                 $this->mImages = self::mergeMap( $this->mImages, $source->getImages() );
1374                 $this->mFileSearchOptions = self::mergeMap(
1375                         $this->mFileSearchOptions,
1376                         $source->getFileSearchOptions()
1377                 );
1378                 $this->mExternalLinks = self::mergeMap( $this->mExternalLinks, $source->getExternalLinks() );
1379                 $this->mInterwikiLinks = self::merge2D(
1380                         $this->mInterwikiLinks,
1381                         $source->getInterwikiLinks()
1382                 );
1383
1384                 // TODO: add a $mergeStrategy parameter to setProperty to allow different
1385                 // kinds of properties to be merged in different ways.
1386                 $this->mProperties = self::mergeMap( $this->mProperties, $source->getProperties() );
1387
1388                 // NOTE: include extension data in "tracking meta data" as well as "html meta data"!
1389                 // TODO: add a $mergeStrategy parameter to setExtensionData to allow different
1390                 // kinds of extension data to be merged in different ways.
1391                 $this->mExtensionData = self::mergeMap(
1392                         $this->mExtensionData,
1393                         $source->mExtensionData
1394                 );
1395         }
1396
1397         private static function mergeMixedList( array $a, array $b ) {
1398                 return array_unique( array_merge( $a, $b ), SORT_REGULAR );
1399         }
1400
1401         private static function mergeList( array $a, array $b ) {
1402                 return array_values( array_unique( array_merge( $a, $b ), SORT_REGULAR ) );
1403         }
1404
1405         private static function mergeMap( array $a, array $b ) {
1406                 return array_replace( $a, $b );
1407         }
1408
1409         private static function merge2D( array $a, array $b ) {
1410                 $values = [];
1411                 $keys = array_merge( array_keys( $a ), array_keys( $b ) );
1412
1413                 foreach ( $keys as $k ) {
1414                         if ( empty( $a[$k] ) ) {
1415                                 $values[$k] = $b[$k];
1416                         } elseif ( empty( $b[$k] ) ) {
1417                                 $values[$k] = $a[$k];
1418                         } elseif ( is_array( $a[$k] ) && is_array( $b[$k] ) ) {
1419                                 $values[$k] = array_replace( $a[$k], $b[$k] );
1420                         } else {
1421                                 $values[$k] = $b[$k];
1422                         }
1423                 }
1424
1425                 return $values;
1426         }
1427
1428         private static function useEachMinValue( array $a, array $b ) {
1429                 $values = [];
1430                 $keys = array_merge( array_keys( $a ), array_keys( $b ) );
1431
1432                 foreach ( $keys as $k ) {
1433                         if ( is_array( $a[$k] ?? null ) && is_array( $b[$k] ?? null ) ) {
1434                                 $values[$k] = self::useEachMinValue( $a[$k], $b[$k] );
1435                         } else {
1436                                 $values[$k] = self::useMinValue( $a[$k] ?? null, $b[$k] ?? null );
1437                         }
1438                 }
1439
1440                 return $values;
1441         }
1442
1443         private static function useMinValue( $a, $b ) {
1444                 if ( $a === null ) {
1445                         return $b;
1446                 }
1447
1448                 if ( $b === null ) {
1449                         return $a;
1450                 }
1451
1452                 return min( $a, $b );
1453         }
1454
1455         private static function useMaxValue( $a, $b ) {
1456                 if ( $a === null ) {
1457                         return $b;
1458                 }
1459
1460                 if ( $b === null ) {
1461                         return $a;
1462                 }
1463
1464                 return max( $a, $b );
1465         }
1466
1467 }