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 $mCategoriesMap 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         /** string CSS classes to use for the wrapping div, stored in the array keys.
 211          * If no class is given, no wrapper is added.
 212          */
 213         private $mWrapperDivClasses = [];
 214
 215         /** @var int Upper bound of expiry based on parse duration */
 216         private $mMaxAdaptiveExpiry = INF;
 217
 218         const EDITSECTION_REGEX =
 219                 '#<(?:mw:)?editsection page="(.*?)" section="(.*?)"(?:/>|>(.*?)(</(?:mw:)?editsection>))#s';
 220
 221         // finalizeAdaptiveCacheExpiry() uses TTL = MAX( m * PARSE_TIME + b, MIN_AR_TTL)
 222         // Current values imply that m=3933.333333 and b=-333.333333
 223         // See https://www.nngroup.com/articles/website-response-times/
 224         const PARSE_FAST_SEC = 0.100; // perceived "fast" page parse
 225         const PARSE_SLOW_SEC = 1.0; // perceived "slow" page parse
 226         const FAST_AR_TTL = 60; // adaptive TTL for "fast" pages
 227         const SLOW_AR_TTL = 3600; // adaptive TTL for "slow" pages
 228         const MIN_AR_TTL = 15; // min adaptive TTL (for sanity, pool counter, and edit stashing)
 229
 230         /**
 231          * @param string|null $text HTML. Use null to indicate that this ParserOutput contains only
 232          *        meta-data, and the HTML output is undetermined, as opposed to empty. Passing null
 233          *        here causes hasText() to return false.
 234          * @param array $languageLinks
 235          * @param array $categoryLinks
 236          * @param bool $unused
 237          * @param string $titletext
 238          */
 239         public function __construct( $text = '', $languageLinks = [], $categoryLinks = [],
 240                 $unused = false, $titletext = ''
 241         ) {
 242                 $this->mText = $text;
 243                 $this->mLanguageLinks = $languageLinks;
 244                 $this->mCategories = $categoryLinks;
 245                 $this->mTitleText = $titletext;
 246         }
 247
 248         /**
 249          * Returns true if text was passed to the constructor, or set using setText(). Returns false
 250          * if null was passed to the $text parameter of the constructor to indicate that this
 251          * ParserOutput only contains meta-data, and the HTML output is undetermined.
 252          *
 253          * @since 1.32
 254          *
 255          * @return bool Whether this ParserOutput contains rendered text. If this returns false, the
 256          *         ParserOutput contains meta-data only.
 257          */
 258         public function hasText() {
 259                 return ( $this->mText !== null );
 260         }
 261
 262         /**
 263          * Get the cacheable text with <mw:editsection> markers still in it. The
 264          * return value is suitable for writing back via setText() but is not valid
 265          * for display to the user.
 266          *
 267          * @return string
 268          * @since 1.27
 269          */
 270         public function getRawText() {
 271                 if ( $this->mText === null ) {
 272                         throw new LogicException( 'This ParserOutput contains no text!' );
 273                 }
 274
 275                 return $this->mText;
 276         }
 277
 278         /**
 279          * Get the output HTML
 280          *
 281          * @param array $options (since 1.31) Transformations to apply to the HTML
 282          *  - allowTOC: (bool) Show the TOC, assuming there were enough headings
 283          *     to generate one and `__NOTOC__` wasn't used. Default is true,
 284          *     but might be statefully overridden.
 285          *  - enableSectionEditLinks: (bool) Include section edit links, assuming
 286          *     section edit link tokens are present in the HTML. Default is true,
 287          *     but might be statefully overridden.
 288          *  - unwrap: (bool) Return text without a wrapper div. Default is false,
 289          *    meaning a wrapper div will be added if getWrapperDivClass() returns
 290          *    a non-empty string.
 291          *  - wrapperDivClass: (string) Wrap the output in a div and apply the given
 292          *    CSS class to that div. This overrides the output of getWrapperDivClass().
 293          *    Setting this to an empty string has the same effect as 'unwrap' => true.
 294          *  - deduplicateStyles: (bool) When true, which is the default, `<style>`
 295          *    tags with the `data-mw-deduplicate` attribute set are deduplicated by
 296          *    value of the attribute: all but the first will be replaced by `<link
 297          *    rel="mw-deduplicated-inline-style" href="mw-data:..."/>` tags, where
 298          *    the scheme-specific-part of the href is the (percent-encoded) value
 299          *    of the `data-mw-deduplicate` attribute.
 300          * @return string HTML
 301          * @return-taint escaped
 302          */
 303         public function getText( $options = [] ) {
 304                 $options += [
 305                         'allowTOC' => true,
 306                         'enableSectionEditLinks' => true,
 307                         'unwrap' => false,
 308                         'deduplicateStyles' => true,
 309                         'wrapperDivClass' => $this->getWrapperDivClass(),
 310                 ];
 311                 $text = $this->getRawText();
 312
 313                 Hooks::runWithoutAbort( 'ParserOutputPostCacheTransform', [ $this, &$text, &$options ] );
 314
 315                 if ( $options['wrapperDivClass'] !== '' && !$options['unwrap'] ) {
 316                         $text = Html::rawElement( 'div', [ 'class' => $options['wrapperDivClass'] ], $text );
 317                 }
 318
 319                 if ( $options['enableSectionEditLinks'] ) {
 320                         $text = preg_replace_callback(
 321                                 self::EDITSECTION_REGEX,
 322                                 function ( $m ) {
 323                                         $editsectionPage = Title::newFromText( htmlspecialchars_decode( $m[1] ) );
 324                                         $editsectionSection = htmlspecialchars_decode( $m[2] );
 325                                         $editsectionContent = isset( $m[4] ) ? Sanitizer::decodeCharReferences( $m[3] ) : null;
 326
 327                                         if ( !is_object( $editsectionPage ) ) {
 328                                                 throw new MWException( "Bad parser output text." );
 329                                         }
 330
 331                                         $context = RequestContext::getMain();
 332                                         return $context->getSkin()->doEditSectionLink(
 333                                                 $editsectionPage,
 334                                                 $editsectionSection,
 335                                                 $editsectionContent,
 336                                                 $context->getLanguage()
 337                                         );
 338                                 },
 339                                 $text
 340                         );
 341                 } else {
 342                         $text = preg_replace( self::EDITSECTION_REGEX, '', $text );
 343                 }
 344
 345                 if ( $options['allowTOC'] ) {
 346                         $text = str_replace( [ Parser::TOC_START, Parser::TOC_END ], '', $text );
 347                 } else {
 348                         $text = preg_replace(
 349                                 '#' . preg_quote( Parser::TOC_START, '#' ) . '.*?' . preg_quote( Parser::TOC_END, '#' ) . '#s',
 350                                 '',
 351                                 $text
 352                         );
 353                 }
 354
 355                 if ( $options['deduplicateStyles'] ) {
 356                         $seen = [];
 357                         $text = preg_replace_callback(
 358                                 '#<style\s+([^>]*data-mw-deduplicate\s*=[^>]*)>.*?</style>#s',
 359                                 function ( $m ) use ( &$seen ) {
 360                                         $attr = Sanitizer::decodeTagAttributes( $m[1] );
 361                                         if ( !isset( $attr['data-mw-deduplicate'] ) ) {
 362                                                 return $m[0];
 363                                         }
 364
 365                                         $key = $attr['data-mw-deduplicate'];
 366                                         if ( !isset( $seen[$key] ) ) {
 367                                                 $seen[$key] = true;
 368                                                 return $m[0];
 369                                         }
 370
 371                                         // We were going to use an empty <style> here, but there
 372                                         // was concern that would be too much overhead for browsers.
 373                                         // So let's hope a <link> with a non-standard rel and href isn't
 374                                         // going to be misinterpreted or mangled by any subsequent processing.
 375                                         return Html::element( 'link', [
 376                                                 'rel' => 'mw-deduplicated-inline-style',
 377                                                 'href' => "mw-data:" . wfUrlencode( $key ),
 378                                         ] );
 379                                 },
 380                                 $text
 381                         );
 382                 }
 383
 384                 // Hydrate slot section header placeholders generated by RevisionRenderer.
 385                 $text = preg_replace_callback(
 386                         '#<mw:slotheader>(.*?)</mw:slotheader>#',
 387                         function ( $m ) {
 388                                 $role = htmlspecialchars_decode( $m[1] );
 389                                 // TODO: map to message, using the interface language. Set lang="xyz" accordingly.
 390                                 $headerText = $role;
 391                                 return $headerText;
 392                         },
 393                         $text
 394                 );
 395                 return $text;
 396         }
 397
 398         /**
 399          * Add a CSS class to use for the wrapping div. If no class is given, no wrapper is added.
 400          *
 401          * @param string $class
 402          */
 403         public function addWrapperDivClass( $class ) {
 404                 $this->mWrapperDivClasses[$class] = true;
 405         }
 406
 407         /**
 408          * Clears the CSS class to use for the wrapping div, effectively disabling the wrapper div
 409          * until addWrapperDivClass() is called.
 410          */
 411         public function clearWrapperDivClass() {
 412                 $this->mWrapperDivClasses = [];
 413         }
 414
 415         /**
 416          * Returns the class (or classes) to be used with the wrapper div for this otuput.
 417          * If there is no wrapper class given, no wrapper div should be added.
 418          * The wrapper div is added automatically by getText().
 419          *
 420          * @return string
 421          */
 422         public function getWrapperDivClass() {
 423                 return implode( ' ', array_keys( $this->mWrapperDivClasses ) );
 424         }
 425
 426         /**
 427          * @param int $id
 428          * @since 1.28
 429          */
 430         public function setSpeculativeRevIdUsed( $id ) {
 431                 $this->mSpeculativeRevId = $id;
 432         }
 433
 434         /**
 435          * @return int|null
 436          * @since 1.28
 437          */
 438         public function getSpeculativeRevIdUsed() {
 439                 return $this->mSpeculativeRevId;
 440         }
 441
 442         public function &getLanguageLinks() {
 443                 return $this->mLanguageLinks;
 444         }
 445
 446         public function getInterwikiLinks() {
 447                 return $this->mInterwikiLinks;
 448         }
 449
 450         public function getCategoryLinks() {
 451                 return array_keys( $this->mCategories );
 452         }
 453
 454         public function &getCategories() {
 455                 return $this->mCategories;
 456         }
 457
 458         /**
 459          * @return array
 460          * @since 1.25
 461          */
 462         public function getIndicators() {
 463                 return $this->mIndicators;
 464         }
 465
 466         public function getTitleText() {
 467                 return $this->mTitleText;
 468         }
 469
 470         public function getSections() {
 471                 return $this->mSections;
 472         }
 473
 474         /**
 475          * @deprecated since 1.31 Use getText() options.
 476          */
 477         public function getEditSectionTokens() {
 478                 wfDeprecated( __METHOD__, '1.31' );
 479                 return true;
 480         }
 481
 482         public function &getLinks() {
 483                 return $this->mLinks;
 484         }
 485
 486         public function &getTemplates() {
 487                 return $this->mTemplates;
 488         }
 489
 490         public function &getTemplateIds() {
 491                 return $this->mTemplateIds;
 492         }
 493
 494         public function &getImages() {
 495                 return $this->mImages;
 496         }
 497
 498         public function &getFileSearchOptions() {
 499                 return $this->mFileSearchOptions;
 500         }
 501
 502         public function &getExternalLinks() {
 503                 return $this->mExternalLinks;
 504         }
 505
 506         public function setNoGallery( $value ) {
 507                 $this->mNoGallery = (bool)$value;
 508         }
 509         public function getNoGallery() {
 510                 return $this->mNoGallery;
 511         }
 512
 513         public function getHeadItems() {
 514                 return $this->mHeadItems;
 515         }
 516
 517         public function getModules() {
 518                 return $this->mModules;
 519         }
 520
 521         public function getModuleScripts() {
 522                 wfDeprecated( __METHOD__, '1.33' );
 523                 return [];
 524         }
 525
 526         public function getModuleStyles() {
 527                 return $this->mModuleStyles;
 528         }
 529
 530         /**
 531          * @return array
 532          * @since 1.23
 533          */
 534         public function getJsConfigVars() {
 535                 return $this->mJsConfigVars;
 536         }
 537
 538         public function getOutputHooks() {
 539                 return (array)$this->mOutputHooks;
 540         }
 541
 542         public function getWarnings() {
 543                 return array_keys( $this->mWarnings );
 544         }
 545
 546         public function getIndexPolicy() {
 547                 return $this->mIndexPolicy;
 548         }
 549
 550         public function getTOCHTML() {
 551                 return $this->mTOCHTML;
 552         }
 553
 554         /**
 555          * @return string|null TS_MW timestamp of the revision content
 556          */
 557         public function getTimestamp() {
 558                 return $this->mTimestamp;
 559         }
 560
 561         public function getLimitReportData() {
 562                 return $this->mLimitReportData;
 563         }
 564
 565         public function getLimitReportJSData() {
 566                 return $this->mLimitReportJSData;
 567         }
 568
 569         /**
 570          * @deprecated since 1.31 Use getText() options.
 571          */
 572         public function getTOCEnabled() {
 573                 wfDeprecated( __METHOD__, '1.31' );
 574                 return true;
 575         }
 576
 577         public function getEnableOOUI() {
 578                 return $this->mEnableOOUI;
 579         }
 580
 581         public function setText( $text ) {
 582                 return wfSetVar( $this->mText, $text );
 583         }
 584
 585         public function setLanguageLinks( $ll ) {
 586                 return wfSetVar( $this->mLanguageLinks, $ll );
 587         }
 588
 589         public function setCategoryLinks( $cl ) {
 590                 return wfSetVar( $this->mCategories, $cl );
 591         }
 592
 593         public function setTitleText( $t ) {
 594                 return wfSetVar( $this->mTitleText, $t );
 595         }
 596
 597         public function setSections( $toc ) {
 598                 return wfSetVar( $this->mSections, $toc );
 599         }
 600
 601         /**
 602          * @deprecated since 1.31 Use getText() options.
 603          */
 604         public function setEditSectionTokens( $t ) {
 605                 wfDeprecated( __METHOD__, '1.31' );
 606                 return true;
 607         }
 608
 609         public function setIndexPolicy( $policy ) {
 610                 return wfSetVar( $this->mIndexPolicy, $policy );
 611         }
 612
 613         public function setTOCHTML( $tochtml ) {
 614                 return wfSetVar( $this->mTOCHTML, $tochtml );
 615         }
 616
 617         public function setTimestamp( $timestamp ) {
 618                 return wfSetVar( $this->mTimestamp, $timestamp );
 619         }
 620
 621         /**
 622          * @deprecated since 1.31 Use getText() options.
 623          */
 624         public function setTOCEnabled( $flag ) {
 625                 wfDeprecated( __METHOD__, '1.31' );
 626                 return true;
 627         }
 628
 629         public function addCategory( $c, $sort ) {
 630                 $this->mCategories[$c] = $sort;
 631         }
 632
 633         /**
 634          * @param string $id
 635          * @param string $content
 636          * @since 1.25
 637          */
 638         public function setIndicator( $id, $content ) {
 639                 $this->mIndicators[$id] = $content;
 640         }
 641
 642         /**
 643          * Enables OOUI, if true, in any OutputPage instance this ParserOutput
 644          * object is added to.
 645          *
 646          * @since 1.26
 647          * @param bool $enable If OOUI should be enabled or not
 648          */
 649         public function setEnableOOUI( $enable = false ) {
 650                 $this->mEnableOOUI = $enable;
 651         }
 652
 653         public function addLanguageLink( $t ) {
 654                 $this->mLanguageLinks[] = $t;
 655         }
 656
 657         public function addWarning( $s ) {
 658                 $this->mWarnings[$s] = 1;
 659         }
 660
 661         public function addOutputHook( $hook, $data = false ) {
 662                 $this->mOutputHooks[] = [ $hook, $data ];
 663         }
 664
 665         public function setNewSection( $value ) {
 666                 $this->mNewSection = (bool)$value;
 667         }
 668         public function hideNewSection( $value ) {
 669                 $this->mHideNewSection = (bool)$value;
 670         }
 671         public function getHideNewSection() {
 672                 return (bool)$this->mHideNewSection;
 673         }
 674         public function getNewSection() {
 675                 return (bool)$this->mNewSection;
 676         }
 677
 678         /**
 679          * Checks, if a url is pointing to the own server
 680          *
 681          * @param string $internal The server to check against
 682          * @param string $url The url to check
 683          * @return bool
 684          */
 685         public static function isLinkInternal( $internal, $url ) {
 686                 return (bool)preg_match( '/^' .
 687                         # If server is proto relative, check also for http/https links
 688                         ( substr( $internal, 0, 2 ) === '//' ? '(?:https?:)?' : '' ) .
 689                         preg_quote( $internal, '/' ) .
 690                         # check for query/path/anchor or end of link in each case
 691                         '(?:[\?\/\#]|$)/i',
 692                         $url
 693                 );
 694         }
 695
 696         public function addExternalLink( $url ) {
 697                 # We don't register links pointing to our own server, unless... :-)
 698                 global $wgServer, $wgRegisterInternalExternals;
 699
 700                 # Replace unnecessary URL escape codes with the referenced character
 701                 # This prevents spammers from hiding links from the filters
 702                 $url = Parser::normalizeLinkUrl( $url );
 703
 704                 $registerExternalLink = true;
 705                 if ( !$wgRegisterInternalExternals ) {
 706                         $registerExternalLink = !self::isLinkInternal( $wgServer, $url );
 707                 }
 708                 if ( $registerExternalLink ) {
 709                         $this->mExternalLinks[$url] = 1;
 710                 }
 711         }
 712
 713         /**
 714          * Record a local or interwiki inline link for saving in future link tables.
 715          *
 716          * @param Title $title
 717          * @param int|null $id Optional known page_id so we can skip the lookup
 718          */
 719         public function addLink( Title $title, $id = null ) {
 720                 if ( $title->isExternal() ) {
 721                         // Don't record interwikis in pagelinks
 722                         $this->addInterwikiLink( $title );
 723                         return;
 724                 }
 725                 $ns = $title->getNamespace();
 726                 $dbk = $title->getDBkey();
 727                 if ( $ns == NS_MEDIA ) {
 728                         // Normalize this pseudo-alias if it makes it down here...
 729                         $ns = NS_FILE;
 730                 } elseif ( $ns == NS_SPECIAL ) {
 731                         // We don't record Special: links currently
 732                         // It might actually be wise to, but we'd need to do some normalization.
 733                         return;
 734                 } elseif ( $dbk === '' ) {
 735                         // Don't record self links -  [[#Foo]]
 736                         return;
 737                 }
 738                 if ( !isset( $this->mLinks[$ns] ) ) {
 739                         $this->mLinks[$ns] = [];
 740                 }
 741                 if ( is_null( $id ) ) {
 742                         $id = $title->getArticleID();
 743                 }
 744                 $this->mLinks[$ns][$dbk] = $id;
 745         }
 746
 747         /**
 748          * Register a file dependency for this output
 749          * @param string $name Title dbKey
 750          * @param string|false|null $timestamp MW timestamp of file creation (or false if non-existing)
 751          * @param string|false|null $sha1 Base 36 SHA-1 of file (or false if non-existing)
 752          */
 753         public function addImage( $name, $timestamp = null, $sha1 = null ) {
 754                 $this->mImages[$name] = 1;
 755                 if ( $timestamp !== null && $sha1 !== null ) {
 756                         $this->mFileSearchOptions[$name] = [ 'time' => $timestamp, 'sha1' => $sha1 ];
 757                 }
 758         }
 759
 760         /**
 761          * Register a template dependency for this output
 762          * @param Title $title
 763          * @param int $page_id
 764          * @param int $rev_id
 765          */
 766         public function addTemplate( $title, $page_id, $rev_id ) {
 767                 $ns = $title->getNamespace();
 768                 $dbk = $title->getDBkey();
 769                 if ( !isset( $this->mTemplates[$ns] ) ) {
 770                         $this->mTemplates[$ns] = [];
 771                 }
 772                 $this->mTemplates[$ns][$dbk] = $page_id;
 773                 if ( !isset( $this->mTemplateIds[$ns] ) ) {
 774                         $this->mTemplateIds[$ns] = [];
 775                 }
 776                 $this->mTemplateIds[$ns][$dbk] = $rev_id; // For versioning
 777         }
 778
 779         /**
 780          * @param Title $title Title object, must be an interwiki link
 781          * @throws MWException If given invalid input
 782          */
 783         public function addInterwikiLink( $title ) {
 784                 if ( !$title->isExternal() ) {
 785                         throw new MWException( 'Non-interwiki link passed, internal parser error.' );
 786                 }
 787                 $prefix = $title->getInterwiki();
 788                 if ( !isset( $this->mInterwikiLinks[$prefix] ) ) {
 789                         $this->mInterwikiLinks[$prefix] = [];
 790                 }
 791                 $this->mInterwikiLinks[$prefix][$title->getDBkey()] = 1;
 792         }
 793
 794         /**
 795          * Add some text to the "<head>".
 796          * If $tag is set, the section with that tag will only be included once
 797          * in a given page.
 798          * @param string $section
 799          * @param string|bool $tag
 800          */
 801         public function addHeadItem( $section, $tag = false ) {
 802                 if ( $tag !== false ) {
 803                         $this->mHeadItems[$tag] = $section;
 804                 } else {
 805                         $this->mHeadItems[] = $section;
 806                 }
 807         }
 808
 809         /**
 810          * @see OutputPage::addModules
 811          */
 812         public function addModules( $modules ) {
 813                 $this->mModules = array_merge( $this->mModules, (array)$modules );
 814         }
 815
 816         /**
 817          * @see OutputPage::addModuleStyles
 818          */
 819         public function addModuleStyles( $modules ) {
 820                 $this->mModuleStyles = array_merge( $this->mModuleStyles, (array)$modules );
 821         }
 822
 823         /**
 824          * Add one or more variables to be set in mw.config in JavaScript.
 825          *
 826          * @param string|array $keys Key or array of key/value pairs.
 827          * @param mixed|null $value [optional] Value of the configuration variable.
 828          * @since 1.23
 829          */
 830         public function addJsConfigVars( $keys, $value = null ) {
 831                 if ( is_array( $keys ) ) {
 832                         foreach ( $keys as $key => $value ) {
 833                                 $this->mJsConfigVars[$key] = $value;
 834                         }
 835                         return;
 836                 }
 837
 838                 $this->mJsConfigVars[$keys] = $value;
 839         }
 840
 841         /**
 842          * Copy items from the OutputPage object into this one
 843          *
 844          * @param OutputPage $out
 845          */
 846         public function addOutputPageMetadata( OutputPage $out ) {
 847                 $this->addModules( $out->getModules() );
 848                 $this->addModuleStyles( $out->getModuleStyles() );
 849                 $this->addJsConfigVars( $out->getJsConfigVars() );
 850
 851                 $this->mHeadItems = array_merge( $this->mHeadItems, $out->getHeadItemsArray() );
 852                 $this->mPreventClickjacking = $this->mPreventClickjacking || $out->getPreventClickjacking();
 853         }
 854
 855         /**
 856          * Add a tracking category, getting the title from a system message,
 857          * or print a debug message if the title is invalid.
 858          *
 859          * Any message used with this function should be registered so it will
 860          * show up on Special:TrackingCategories. Core messages should be added
 861          * to SpecialTrackingCategories::$coreTrackingCategories, and extensions
 862          * should add to "TrackingCategories" in their extension.json.
 863          *
 864          * @todo Migrate some code to TrackingCategories
 865          *
 866          * @param string $msg Message key
 867          * @param Title $title title of the page which is being tracked
 868          * @return bool Whether the addition was successful
 869          * @since 1.25
 870          */
 871         public function addTrackingCategory( $msg, $title ) {
 872                 if ( $title->isSpecialPage() ) {
 873                         wfDebug( __METHOD__ . ": Not adding tracking category $msg to special page!\n" );
 874                         return false;
 875                 }
 876
 877                 // Important to parse with correct title (T33469)
 878                 $cat = wfMessage( $msg )
 879                         ->title( $title )
 880                         ->inContentLanguage()
 881                         ->text();
 882
 883                 # Allow tracking categories to be disabled by setting them to "-"
 884                 if ( $cat === '-' ) {
 885                         return false;
 886                 }
 887
 888                 $containerCategory = Title::makeTitleSafe( NS_CATEGORY, $cat );
 889                 if ( $containerCategory ) {
 890                         $this->addCategory( $containerCategory->getDBkey(), $this->getProperty( 'defaultsort' ) ?: '' );
 891                         return true;
 892                 } else {
 893                         wfDebug( __METHOD__ . ": [[MediaWiki:$msg]] is not a valid title!\n" );
 894                         return false;
 895                 }
 896         }
 897
 898         /**
 899          * Override the title to be used for display
 900          *
 901          * @note this is assumed to have been validated
 902          * (check equal normalisation, etc.)
 903          *
 904          * @note this is expected to be safe HTML,
 905          * ready to be served to the client.
 906          *
 907          * @param string $text Desired title text
 908          */
 909         public function setDisplayTitle( $text ) {
 910                 $this->setTitleText( $text );
 911                 $this->setProperty( 'displaytitle', $text );
 912         }
 913
 914         /**
 915          * Get the title to be used for display.
 916          *
 917          * As per the contract of setDisplayTitle(), this is safe HTML,
 918          * ready to be served to the client.
 919          *
 920          * @return string HTML
 921          */
 922         public function getDisplayTitle() {
 923                 $t = $this->getTitleText();
 924                 if ( $t === '' ) {
 925                         return false;
 926                 }
 927                 return $t;
 928         }
 929
 930         /**
 931          * Fairly generic flag setter thingy.
 932          * @param string $flag
 933          */
 934         public function setFlag( $flag ) {
 935                 $this->mFlags[$flag] = true;
 936         }
 937
 938         public function getFlag( $flag ) {
 939                 return isset( $this->mFlags[$flag] );
 940         }
 941
 942         /**
 943          * Set a property to be stored in the page_props database table.
 944          *
 945          * page_props is a key value store indexed by the page ID. This allows
 946          * the parser to set a property on a page which can then be quickly
 947          * retrieved given the page ID or via a DB join when given the page
 948          * title.
 949          *
 950          * Since 1.23, page_props are also indexed by numeric value, to allow
 951          * for efficient "top k" queries of pages wrt a given property.
 952          *
 953          * setProperty() is thus used to propagate properties from the parsed
 954          * page to request contexts other than a page view of the currently parsed
 955          * article.
 956          *
 957          * Some applications examples:
 958          *
 959          *   * To implement hidden categories, hiding pages from category listings
 960          *     by storing a property.
 961          *
 962          *   * Overriding the displayed article title (ParserOutput::setDisplayTitle()).
 963          *
 964          *   * To implement image tagging, for example displaying an icon on an
 965          *     image thumbnail to indicate that it is listed for deletion on
 966          *     Wikimedia Commons.
 967          *     This is not actually implemented, yet but would be pretty cool.
 968          *
 969          * @note Do not use setProperty() to set a property which is only used
 970          * in a context where the ParserOutput object itself is already available,
 971          * for example a normal page view. There is no need to save such a property
 972          * in the database since the text is already parsed. You can just hook
 973          * OutputPageParserOutput and get your data out of the ParserOutput object.
 974          *
 975          * If you are writing an extension where you want to set a property in the
 976          * parser which is used by an OutputPageParserOutput hook, you have to
 977          * associate the extension data directly with the ParserOutput object.
 978          * Since MediaWiki 1.21, you can use setExtensionData() to do this:
 979          *
 980          * @par Example:
 981          * @code
 982          *    $parser->getOutput()->setExtensionData( 'my_ext_foo', '...' );
 983          * @endcode
 984          *
 985          * And then later, in OutputPageParserOutput or similar:
 986          *
 987          * @par Example:
 988          * @code
 989          *    $output->getExtensionData( 'my_ext_foo' );
 990          * @endcode
 991          *
 992          * In MediaWiki 1.20 and older, you have to use a custom member variable
 993          * within the ParserOutput object:
 994          *
 995          * @par Example:
 996          * @code
 997          *    $parser->getOutput()->my_ext_foo = '...';
 998          * @endcode
 999          * @param string $name
1000          * @param mixed $value
1001          */
1002         public function setProperty( $name, $value ) {
1003                 $this->mProperties[$name] = $value;
1004         }
1005
1006         /**
1007          * @param string $name The property name to look up.
1008          *
1009          * @return mixed|bool The value previously set using setProperty(). False if null or no value
1010          * was set for the given property name.
1011          *
1012          * @note You need to use getProperties() to check for boolean and null properties.
1013          */
1014         public function getProperty( $name ) {
1015                 return $this->mProperties[$name] ?? false;
1016         }
1017
1018         public function unsetProperty( $name ) {
1019                 unset( $this->mProperties[$name] );
1020         }
1021
1022         public function getProperties() {
1023                 if ( !isset( $this->mProperties ) ) {
1024                         $this->mProperties = [];
1025                 }
1026                 return $this->mProperties;
1027         }
1028
1029         /**
1030          * Returns the options from its ParserOptions which have been taken
1031          * into account to produce this output.
1032          * @return string[]
1033          */
1034         public function getUsedOptions() {
1035                 if ( !isset( $this->mAccessedOptions ) ) {
1036                         return [];
1037                 }
1038                 return array_keys( $this->mAccessedOptions );
1039         }
1040
1041         /**
1042          * Tags a parser option for use in the cache key for this parser output.
1043          * Registered as a watcher at ParserOptions::registerWatcher() by Parser::clearState().
1044          * The information gathered here is available via getUsedOptions(),
1045          * and is used by ParserCache::save().
1046          *
1047          * @see ParserCache::getKey
1048          * @see ParserCache::save
1049          * @see ParserOptions::addExtraKey
1050          * @see ParserOptions::optionsHash
1051          * @param string $option
1052          */
1053         public function recordOption( $option ) {
1054                 $this->mAccessedOptions[$option] = true;
1055         }
1056
1057         /**
1058          * Attaches arbitrary data to this ParserObject. This can be used to store some information in
1059          * the ParserOutput object for later use during page output. The data will be cached along with
1060          * the ParserOutput object, but unlike data set using setProperty(), it is not recorded in the
1061          * database.
1062          *
1063          * This method is provided to overcome the unsafe practice of attaching extra information to a
1064          * ParserObject by directly assigning member variables.
1065          *
1066          * To use setExtensionData() to pass extension information from a hook inside the parser to a
1067          * hook in the page output, use this in the parser hook:
1068          *
1069          * @par Example:
1070          * @code
1071          *    $parser->getOutput()->setExtensionData( 'my_ext_foo', '...' );
1072          * @endcode
1073          *
1074          * And then later, in OutputPageParserOutput or similar:
1075          *
1076          * @par Example:
1077          * @code
1078          *    $output->getExtensionData( 'my_ext_foo' );
1079          * @endcode
1080          *
1081          * In MediaWiki 1.20 and older, you have to use a custom member variable
1082          * within the ParserOutput object:
1083          *
1084          * @par Example:
1085          * @code
1086          *    $parser->getOutput()->my_ext_foo = '...';
1087          * @endcode
1088          *
1089          * @since 1.21
1090          *
1091          * @param string $key The key for accessing the data. Extensions should take care to avoid
1092          *   conflicts in naming keys. It is suggested to use the extension's name as a prefix.
1093          *
1094          * @param mixed $value The value to set. Setting a value to null is equivalent to removing
1095          *   the value.
1096          */
1097         public function setExtensionData( $key, $value ) {
1098                 if ( $value === null ) {
1099                         unset( $this->mExtensionData[$key] );
1100                 } else {
1101                         $this->mExtensionData[$key] = $value;
1102                 }
1103         }
1104
1105         /**
1106          * Gets extensions data previously attached to this ParserOutput using setExtensionData().
1107          * Typically, such data would be set while parsing the page, e.g. by a parser function.
1108          *
1109          * @since 1.21
1110          *
1111          * @param string $key The key to look up.
1112          *
1113          * @return mixed|null The value previously set for the given key using setExtensionData()
1114          *         or null if no value was set for this key.
1115          */
1116         public function getExtensionData( $key ) {
1117                 return $this->mExtensionData[$key] ?? null;
1118         }
1119
1120         private static function getTimes( $clock = null ) {
1121                 $ret = [];
1122                 if ( !$clock || $clock === 'wall' ) {
1123                         $ret['wall'] = microtime( true );
1124                 }
1125                 if ( !$clock || $clock === 'cpu' ) {
1126                         $ru = wfGetRusage();
1127                         if ( $ru ) {
1128                                 $ret['cpu'] = $ru['ru_utime.tv_sec'] + $ru['ru_utime.tv_usec'] / 1e6;
1129                                 $ret['cpu'] += $ru['ru_stime.tv_sec'] + $ru['ru_stime.tv_usec'] / 1e6;
1130                         }
1131                 }
1132                 return $ret;
1133         }
1134
1135         /**
1136          * Resets the parse start timestamps for future calls to getTimeSinceStart()
1137          * @since 1.22
1138          */
1139         public function resetParseStartTime() {
1140                 $this->mParseStartTime = self::getTimes();
1141         }
1142
1143         /**
1144          * Returns the time since resetParseStartTime() was last called
1145          *
1146          * Clocks available are:
1147          *  - wall: Wall clock time
1148          *  - cpu: CPU time (requires getrusage)
1149          *
1150          * @since 1.22
1151          * @param string $clock
1152          * @return float|null
1153          */
1154         public function getTimeSinceStart( $clock ) {
1155                 if ( !isset( $this->mParseStartTime[$clock] ) ) {
1156                         return null;
1157                 }
1158
1159                 $end = self::getTimes( $clock );
1160                 return $end[$clock] - $this->mParseStartTime[$clock];
1161         }
1162
1163         /**
1164          * Sets parser limit report data for a key
1165          *
1166          * The key is used as the prefix for various messages used for formatting:
1167          *  - $key: The label for the field in the limit report
1168          *  - $key-value-text: Message used to format the value in the "NewPP limit
1169          *      report" HTML comment. If missing, uses $key-format.
1170          *  - $key-value-html: Message used to format the value in the preview
1171          *      limit report table. If missing, uses $key-format.
1172          *  - $key-value: Message used to format the value. If missing, uses "$1".
1173          *
1174          * Note that all values are interpreted as wikitext, and so should be
1175          * encoded with htmlspecialchars() as necessary, but should avoid complex
1176          * HTML for sanity of display in the "NewPP limit report" comment.
1177          *
1178          * @since 1.22
1179          * @param string $key Message key
1180          * @param mixed $value Appropriate for Message::params()
1181          */
1182         public function setLimitReportData( $key, $value ) {
1183                 $this->mLimitReportData[$key] = $value;
1184
1185                 if ( is_array( $value ) ) {
1186                         if ( array_keys( $value ) === [ 0, 1 ]
1187                                 && is_numeric( $value[0] )
1188                                 && is_numeric( $value[1] )
1189                         ) {
1190                                 $data = [ 'value' => $value[0], 'limit' => $value[1] ];
1191                         } else {
1192                                 $data = $value;
1193                         }
1194                 } else {
1195                         $data = $value;
1196                 }
1197
1198                 if ( strpos( $key, '-' ) ) {
1199                         list( $ns, $name ) = explode( '-', $key, 2 );
1200                         $this->mLimitReportJSData[$ns][$name] = $data;
1201                 } else {
1202                         $this->mLimitReportJSData[$key] = $data;
1203                 }
1204         }
1205
1206         /**
1207          * Check whether the cache TTL was lowered due to dynamic content
1208          *
1209          * When content is determined by more than hard state (e.g. page edits),
1210          * such as template/file transclusions based on the current timestamp or
1211          * extension tags that generate lists based on queries, this return true.
1212          *
1213          * @return bool
1214          * @since 1.25
1215          */
1216         public function hasDynamicContent() {
1217                 global $wgParserCacheExpireTime;
1218
1219                 return $this->getCacheExpiry() < $wgParserCacheExpireTime;
1220         }
1221
1222         /**
1223          * Get or set the prevent-clickjacking flag
1224          *
1225          * @since 1.24
1226          * @param bool|null $flag New flag value, or null to leave it unchanged
1227          * @return bool Old flag value
1228          */
1229         public function preventClickjacking( $flag = null ) {
1230                 return wfSetVar( $this->mPreventClickjacking, $flag );
1231         }
1232
1233         /**
1234          * Lower the runtime adaptive TTL to at most this value
1235          *
1236          * @param int $ttl
1237          * @since 1.28
1238          */
1239         public function updateRuntimeAdaptiveExpiry( $ttl ) {
1240                 $this->mMaxAdaptiveExpiry = min( $ttl, $this->mMaxAdaptiveExpiry );
1241                 $this->updateCacheExpiry( $ttl );
1242         }
1243
1244         /**
1245          * Call this when parsing is done to lower the TTL based on low parse times
1246          *
1247          * @since 1.28
1248          */
1249         public function finalizeAdaptiveCacheExpiry() {
1250                 if ( is_infinite( $this->mMaxAdaptiveExpiry ) ) {
1251                         return; // not set
1252                 }
1253
1254                 $runtime = $this->getTimeSinceStart( 'wall' );
1255                 if ( is_float( $runtime ) ) {
1256                         $slope = ( self::SLOW_AR_TTL - self::FAST_AR_TTL )
1257                                 / ( self::PARSE_SLOW_SEC - self::PARSE_FAST_SEC );
1258                         // SLOW_AR_TTL = PARSE_SLOW_SEC * $slope + $point
1259                         $point = self::SLOW_AR_TTL - self::PARSE_SLOW_SEC * $slope;
1260
1261                         $adaptiveTTL = min(
1262                                 max( $slope * $runtime + $point, self::MIN_AR_TTL ),
1263                                 $this->mMaxAdaptiveExpiry
1264                         );
1265                         $this->updateCacheExpiry( $adaptiveTTL );
1266                 }
1267         }
1268
1269         public function __sleep() {
1270                 return array_diff(
1271                         array_keys( get_object_vars( $this ) ),
1272                         [ 'mParseStartTime' ]
1273                 );
1274         }
1275
1276         /**
1277          * Merges internal metadata such as flags, accessed options, and profiling info
1278          * from $source into this ParserOutput. This should be used whenever the state of $source
1279          * has any impact on the state of this ParserOutput.
1280          *
1281          * @param ParserOutput $source
1282          */
1283         public function mergeInternalMetaDataFrom( ParserOutput $source ) {
1284                 $this->mOutputHooks = self::mergeList( $this->mOutputHooks, $source->getOutputHooks() );
1285                 $this->mWarnings = self::mergeMap( $this->mWarnings, $source->mWarnings ); // don't use getter
1286                 $this->mTimestamp = $this->useMaxValue( $this->mTimestamp, $source->getTimestamp() );
1287
1288                 if ( $this->mSpeculativeRevId && $source->mSpeculativeRevId
1289                         && $this->mSpeculativeRevId !== $source->mSpeculativeRevId
1290                 ) {
1291                         wfLogWarning(
1292                                 'Inconsistent speculative revision ID encountered while merging parser output!'
1293                         );
1294                 }
1295
1296                 $this->mSpeculativeRevId = $this->useMaxValue(
1297                         $this->mSpeculativeRevId,
1298                         $source->getSpeculativeRevIdUsed()
1299                 );
1300                 $this->mParseStartTime = $this->useEachMinValue(
1301                         $this->mParseStartTime,
1302                         $source->mParseStartTime
1303                 );
1304
1305                 $this->mFlags = self::mergeMap( $this->mFlags, $source->mFlags );
1306                 $this->mAccessedOptions = self::mergeMap( $this->mAccessedOptions, $source->mAccessedOptions );
1307
1308                 // TODO: maintain per-slot limit reports!
1309                 if ( empty( $this->mLimitReportData ) ) {
1310                         $this->mLimitReportData = $source->mLimitReportData;
1311                 }
1312                 if ( empty( $this->mLimitReportJSData ) ) {
1313                         $this->mLimitReportJSData = $source->mLimitReportJSData;
1314                 }
1315         }
1316
1317         /**
1318          * Merges HTML metadata such as head items, JS config vars, and HTTP cache control info
1319          * from $source into this ParserOutput. This should be used whenever the HTML in $source
1320          * has been somehow mered into the HTML of this ParserOutput.
1321          *
1322          * @param ParserOutput $source
1323          */
1324         public function mergeHtmlMetaDataFrom( ParserOutput $source ) {
1325                 // HTML and HTTP
1326                 $this->mHeadItems = self::mergeMixedList( $this->mHeadItems, $source->getHeadItems() );
1327                 $this->mModules = self::mergeList( $this->mModules, $source->getModules() );
1328                 $this->mModuleStyles = self::mergeList( $this->mModuleStyles, $source->getModuleStyles() );
1329                 $this->mJsConfigVars = self::mergeMap( $this->mJsConfigVars, $source->getJsConfigVars() );
1330                 $this->mMaxAdaptiveExpiry = min( $this->mMaxAdaptiveExpiry, $source->mMaxAdaptiveExpiry );
1331
1332                 // "noindex" always wins!
1333                 if ( $this->mIndexPolicy === 'noindex' || $source->mIndexPolicy === 'noindex' ) {
1334                         $this->mIndexPolicy = 'noindex';
1335                 } elseif ( $this->mIndexPolicy !== 'index' ) {
1336                         $this->mIndexPolicy = $source->mIndexPolicy;
1337                 }
1338
1339                 // Skin control
1340                 $this->mNewSection = $this->mNewSection || $source->getNewSection();
1341                 $this->mHideNewSection = $this->mHideNewSection || $source->getHideNewSection();
1342                 $this->mNoGallery = $this->mNoGallery || $source->getNoGallery();
1343                 $this->mEnableOOUI = $this->mEnableOOUI || $source->getEnableOOUI();
1344                 $this->mPreventClickjacking = $this->mPreventClickjacking || $source->preventClickjacking();
1345
1346                 // TODO: we'll have to be smarter about this!
1347                 $this->mSections = array_merge( $this->mSections, $source->getSections() );
1348                 $this->mTOCHTML .= $source->mTOCHTML;
1349
1350                 // XXX: we don't want to concatenate title text, so first write wins.
1351                 // We should use the first *modified* title text, but we don't have the original to check.
1352                 if ( $this->mTitleText === null || $this->mTitleText === '' ) {
1353                         $this->mTitleText = $source->mTitleText;
1354                 }
1355
1356                 // class names are stored in array keys
1357                 $this->mWrapperDivClasses = self::mergeMap(
1358                         $this->mWrapperDivClasses,
1359                         $source->mWrapperDivClasses
1360                 );
1361
1362                 // NOTE: last write wins, same as within one ParserOutput
1363                 $this->mIndicators = self::mergeMap( $this->mIndicators, $source->getIndicators() );
1364
1365                 // NOTE: include extension data in "tracking meta data" as well as "html meta data"!
1366                 // TODO: add a $mergeStrategy parameter to setExtensionData to allow different
1367                 // kinds of extension data to be merged in different ways.
1368                 $this->mExtensionData = self::mergeMap(
1369                         $this->mExtensionData,
1370                         $source->mExtensionData
1371                 );
1372         }
1373
1374         /**
1375          * Merges dependency tracking metadata such as backlinks, images used, and extension data
1376          * from $source into this ParserOutput. This allows dependency tracking to be done for the
1377          * combined output of multiple content slots.
1378          *
1379          * @param ParserOutput $source
1380          */
1381         public function mergeTrackingMetaDataFrom( ParserOutput $source ) {
1382                 $this->mLanguageLinks = self::mergeList( $this->mLanguageLinks, $source->getLanguageLinks() );
1383                 $this->mCategories = self::mergeMap( $this->mCategories, $source->getCategories() );
1384                 $this->mLinks = self::merge2D( $this->mLinks, $source->getLinks() );
1385                 $this->mTemplates = self::merge2D( $this->mTemplates, $source->getTemplates() );
1386                 $this->mTemplateIds = self::merge2D( $this->mTemplateIds, $source->getTemplateIds() );
1387                 $this->mImages = self::mergeMap( $this->mImages, $source->getImages() );
1388                 $this->mFileSearchOptions = self::mergeMap(
1389                         $this->mFileSearchOptions,
1390                         $source->getFileSearchOptions()
1391                 );
1392                 $this->mExternalLinks = self::mergeMap( $this->mExternalLinks, $source->getExternalLinks() );
1393                 $this->mInterwikiLinks = self::merge2D(
1394                         $this->mInterwikiLinks,
1395                         $source->getInterwikiLinks()
1396                 );
1397
1398                 // TODO: add a $mergeStrategy parameter to setProperty to allow different
1399                 // kinds of properties to be merged in different ways.
1400                 $this->mProperties = self::mergeMap( $this->mProperties, $source->getProperties() );
1401
1402                 // NOTE: include extension data in "tracking meta data" as well as "html meta data"!
1403                 // TODO: add a $mergeStrategy parameter to setExtensionData to allow different
1404                 // kinds of extension data to be merged in different ways.
1405                 $this->mExtensionData = self::mergeMap(
1406                         $this->mExtensionData,
1407                         $source->mExtensionData
1408                 );
1409         }
1410
1411         private static function mergeMixedList( array $a, array $b ) {
1412                 return array_unique( array_merge( $a, $b ), SORT_REGULAR );
1413         }
1414
1415         private static function mergeList( array $a, array $b ) {
1416                 return array_values( array_unique( array_merge( $a, $b ), SORT_REGULAR ) );
1417         }
1418
1419         private static function mergeMap( array $a, array $b ) {
1420                 return array_replace( $a, $b );
1421         }
1422
1423         private static function merge2D( array $a, array $b ) {
1424                 $values = [];
1425                 $keys = array_merge( array_keys( $a ), array_keys( $b ) );
1426
1427                 foreach ( $keys as $k ) {
1428                         if ( empty( $a[$k] ) ) {
1429                                 $values[$k] = $b[$k];
1430                         } elseif ( empty( $b[$k] ) ) {
1431                                 $values[$k] = $a[$k];
1432                         } elseif ( is_array( $a[$k] ) && is_array( $b[$k] ) ) {
1433                                 $values[$k] = array_replace( $a[$k], $b[$k] );
1434                         } else {
1435                                 $values[$k] = $b[$k];
1436                         }
1437                 }
1438
1439                 return $values;
1440         }
1441
1442         private static function useEachMinValue( array $a, array $b ) {
1443                 $values = [];
1444                 $keys = array_merge( array_keys( $a ), array_keys( $b ) );
1445
1446                 foreach ( $keys as $k ) {
1447                         if ( is_array( $a[$k] ?? null ) && is_array( $b[$k] ?? null ) ) {
1448                                 $values[$k] = self::useEachMinValue( $a[$k], $b[$k] );
1449                         } else {
1450                                 $values[$k] = self::useMinValue( $a[$k] ?? null, $b[$k] ?? null );
1451                         }
1452                 }
1453
1454                 return $values;
1455         }
1456
1457         private static function useMinValue( $a, $b ) {
1458                 if ( $a === null ) {
1459                         return $b;
1460                 }
1461
1462                 if ( $b === null ) {
1463                         return $a;
1464                 }
1465
1466                 return min( $a, $b );
1467         }
1468
1469         private static function useMaxValue( $a, $b ) {
1470                 if ( $a === null ) {
1471                         return $b;
1472                 }
1473
1474                 if ( $b === null ) {
1475                         return $a;
1476                 }
1477
1478                 return max( $a, $b );
1479         }
1480
1481 }