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         /** 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         public function &getLinks() {
 475                 return $this->mLinks;
 476         }
 477
 478         public function &getTemplates() {
 479                 return $this->mTemplates;
 480         }
 481
 482         public function &getTemplateIds() {
 483                 return $this->mTemplateIds;
 484         }
 485
 486         public function &getImages() {
 487                 return $this->mImages;
 488         }
 489
 490         public function &getFileSearchOptions() {
 491                 return $this->mFileSearchOptions;
 492         }
 493
 494         public function &getExternalLinks() {
 495                 return $this->mExternalLinks;
 496         }
 497
 498         public function setNoGallery( $value ) {
 499                 $this->mNoGallery = (bool)$value;
 500         }
 501         public function getNoGallery() {
 502                 return $this->mNoGallery;
 503         }
 504
 505         public function getHeadItems() {
 506                 return $this->mHeadItems;
 507         }
 508
 509         public function getModules() {
 510                 return $this->mModules;
 511         }
 512
 513         public function getModuleStyles() {
 514                 return $this->mModuleStyles;
 515         }
 516
 517         /**
 518          * @return array
 519          * @since 1.23
 520          */
 521         public function getJsConfigVars() {
 522                 return $this->mJsConfigVars;
 523         }
 524
 525         public function getOutputHooks() {
 526                 return (array)$this->mOutputHooks;
 527         }
 528
 529         public function getWarnings() {
 530                 return array_keys( $this->mWarnings );
 531         }
 532
 533         public function getIndexPolicy() {
 534                 return $this->mIndexPolicy;
 535         }
 536
 537         public function getTOCHTML() {
 538                 return $this->mTOCHTML;
 539         }
 540
 541         /**
 542          * @return string|null TS_MW timestamp of the revision content
 543          */
 544         public function getTimestamp() {
 545                 return $this->mTimestamp;
 546         }
 547
 548         public function getLimitReportData() {
 549                 return $this->mLimitReportData;
 550         }
 551
 552         public function getLimitReportJSData() {
 553                 return $this->mLimitReportJSData;
 554         }
 555
 556         public function getEnableOOUI() {
 557                 return $this->mEnableOOUI;
 558         }
 559
 560         public function setText( $text ) {
 561                 return wfSetVar( $this->mText, $text );
 562         }
 563
 564         public function setLanguageLinks( $ll ) {
 565                 return wfSetVar( $this->mLanguageLinks, $ll );
 566         }
 567
 568         public function setCategoryLinks( $cl ) {
 569                 return wfSetVar( $this->mCategories, $cl );
 570         }
 571
 572         public function setTitleText( $t ) {
 573                 return wfSetVar( $this->mTitleText, $t );
 574         }
 575
 576         public function setSections( $toc ) {
 577                 return wfSetVar( $this->mSections, $toc );
 578         }
 579
 580         public function setIndexPolicy( $policy ) {
 581                 return wfSetVar( $this->mIndexPolicy, $policy );
 582         }
 583
 584         public function setTOCHTML( $tochtml ) {
 585                 return wfSetVar( $this->mTOCHTML, $tochtml );
 586         }
 587
 588         public function setTimestamp( $timestamp ) {
 589                 return wfSetVar( $this->mTimestamp, $timestamp );
 590         }
 591
 592         public function addCategory( $c, $sort ) {
 593                 $this->mCategories[$c] = $sort;
 594         }
 595
 596         /**
 597          * @param string $id
 598          * @param string $content
 599          * @since 1.25
 600          */
 601         public function setIndicator( $id, $content ) {
 602                 $this->mIndicators[$id] = $content;
 603         }
 604
 605         /**
 606          * Enables OOUI, if true, in any OutputPage instance this ParserOutput
 607          * object is added to.
 608          *
 609          * @since 1.26
 610          * @param bool $enable If OOUI should be enabled or not
 611          */
 612         public function setEnableOOUI( $enable = false ) {
 613                 $this->mEnableOOUI = $enable;
 614         }
 615
 616         public function addLanguageLink( $t ) {
 617                 $this->mLanguageLinks[] = $t;
 618         }
 619
 620         public function addWarning( $s ) {
 621                 $this->mWarnings[$s] = 1;
 622         }
 623
 624         public function addOutputHook( $hook, $data = false ) {
 625                 $this->mOutputHooks[] = [ $hook, $data ];
 626         }
 627
 628         public function setNewSection( $value ) {
 629                 $this->mNewSection = (bool)$value;
 630         }
 631         public function hideNewSection( $value ) {
 632                 $this->mHideNewSection = (bool)$value;
 633         }
 634         public function getHideNewSection() {
 635                 return (bool)$this->mHideNewSection;
 636         }
 637         public function getNewSection() {
 638                 return (bool)$this->mNewSection;
 639         }
 640
 641         /**
 642          * Checks, if a url is pointing to the own server
 643          *
 644          * @param string $internal The server to check against
 645          * @param string $url The url to check
 646          * @return bool
 647          */
 648         public static function isLinkInternal( $internal, $url ) {
 649                 return (bool)preg_match( '/^' .
 650                         # If server is proto relative, check also for http/https links
 651                         ( substr( $internal, 0, 2 ) === '//' ? '(?:https?:)?' : '' ) .
 652                         preg_quote( $internal, '/' ) .
 653                         # check for query/path/anchor or end of link in each case
 654                         '(?:[\?\/\#]|$)/i',
 655                         $url
 656                 );
 657         }
 658
 659         public function addExternalLink( $url ) {
 660                 # We don't register links pointing to our own server, unless... :-)
 661                 global $wgServer, $wgRegisterInternalExternals;
 662
 663                 # Replace unnecessary URL escape codes with the referenced character
 664                 # This prevents spammers from hiding links from the filters
 665                 $url = Parser::normalizeLinkUrl( $url );
 666
 667                 $registerExternalLink = true;
 668                 if ( !$wgRegisterInternalExternals ) {
 669                         $registerExternalLink = !self::isLinkInternal( $wgServer, $url );
 670                 }
 671                 if ( $registerExternalLink ) {
 672                         $this->mExternalLinks[$url] = 1;
 673                 }
 674         }
 675
 676         /**
 677          * Record a local or interwiki inline link for saving in future link tables.
 678          *
 679          * @param Title $title
 680          * @param int|null $id Optional known page_id so we can skip the lookup
 681          */
 682         public function addLink( Title $title, $id = null ) {
 683                 if ( $title->isExternal() ) {
 684                         // Don't record interwikis in pagelinks
 685                         $this->addInterwikiLink( $title );
 686                         return;
 687                 }
 688                 $ns = $title->getNamespace();
 689                 $dbk = $title->getDBkey();
 690                 if ( $ns == NS_MEDIA ) {
 691                         // Normalize this pseudo-alias if it makes it down here...
 692                         $ns = NS_FILE;
 693                 } elseif ( $ns == NS_SPECIAL ) {
 694                         // We don't record Special: links currently
 695                         // It might actually be wise to, but we'd need to do some normalization.
 696                         return;
 697                 } elseif ( $dbk === '' ) {
 698                         // Don't record self links -  [[#Foo]]
 699                         return;
 700                 }
 701                 if ( !isset( $this->mLinks[$ns] ) ) {
 702                         $this->mLinks[$ns] = [];
 703                 }
 704                 if ( is_null( $id ) ) {
 705                         $id = $title->getArticleID();
 706                 }
 707                 $this->mLinks[$ns][$dbk] = $id;
 708         }
 709
 710         /**
 711          * Register a file dependency for this output
 712          * @param string $name Title dbKey
 713          * @param string|false|null $timestamp MW timestamp of file creation (or false if non-existing)
 714          * @param string|false|null $sha1 Base 36 SHA-1 of file (or false if non-existing)
 715          */
 716         public function addImage( $name, $timestamp = null, $sha1 = null ) {
 717                 $this->mImages[$name] = 1;
 718                 if ( $timestamp !== null && $sha1 !== null ) {
 719                         $this->mFileSearchOptions[$name] = [ 'time' => $timestamp, 'sha1' => $sha1 ];
 720                 }
 721         }
 722
 723         /**
 724          * Register a template dependency for this output
 725          * @param Title $title
 726          * @param int $page_id
 727          * @param int $rev_id
 728          */
 729         public function addTemplate( $title, $page_id, $rev_id ) {
 730                 $ns = $title->getNamespace();
 731                 $dbk = $title->getDBkey();
 732                 if ( !isset( $this->mTemplates[$ns] ) ) {
 733                         $this->mTemplates[$ns] = [];
 734                 }
 735                 $this->mTemplates[$ns][$dbk] = $page_id;
 736                 if ( !isset( $this->mTemplateIds[$ns] ) ) {
 737                         $this->mTemplateIds[$ns] = [];
 738                 }
 739                 $this->mTemplateIds[$ns][$dbk] = $rev_id; // For versioning
 740         }
 741
 742         /**
 743          * @param Title $title Title object, must be an interwiki link
 744          * @throws MWException If given invalid input
 745          */
 746         public function addInterwikiLink( $title ) {
 747                 if ( !$title->isExternal() ) {
 748                         throw new MWException( 'Non-interwiki link passed, internal parser error.' );
 749                 }
 750                 $prefix = $title->getInterwiki();
 751                 if ( !isset( $this->mInterwikiLinks[$prefix] ) ) {
 752                         $this->mInterwikiLinks[$prefix] = [];
 753                 }
 754                 $this->mInterwikiLinks[$prefix][$title->getDBkey()] = 1;
 755         }
 756
 757         /**
 758          * Add some text to the "<head>".
 759          * If $tag is set, the section with that tag will only be included once
 760          * in a given page.
 761          * @param string $section
 762          * @param string|bool $tag
 763          */
 764         public function addHeadItem( $section, $tag = false ) {
 765                 if ( $tag !== false ) {
 766                         $this->mHeadItems[$tag] = $section;
 767                 } else {
 768                         $this->mHeadItems[] = $section;
 769                 }
 770         }
 771
 772         /**
 773          * @see OutputPage::addModules
 774          */
 775         public function addModules( $modules ) {
 776                 $this->mModules = array_merge( $this->mModules, (array)$modules );
 777         }
 778
 779         /**
 780          * @see OutputPage::addModuleStyles
 781          */
 782         public function addModuleStyles( $modules ) {
 783                 $this->mModuleStyles = array_merge( $this->mModuleStyles, (array)$modules );
 784         }
 785
 786         /**
 787          * Add one or more variables to be set in mw.config in JavaScript.
 788          *
 789          * @param string|array $keys Key or array of key/value pairs.
 790          * @param mixed|null $value [optional] Value of the configuration variable.
 791          * @since 1.23
 792          */
 793         public function addJsConfigVars( $keys, $value = null ) {
 794                 if ( is_array( $keys ) ) {
 795                         foreach ( $keys as $key => $value ) {
 796                                 $this->mJsConfigVars[$key] = $value;
 797                         }
 798                         return;
 799                 }
 800
 801                 $this->mJsConfigVars[$keys] = $value;
 802         }
 803
 804         /**
 805          * Copy items from the OutputPage object into this one
 806          *
 807          * @param OutputPage $out
 808          */
 809         public function addOutputPageMetadata( OutputPage $out ) {
 810                 $this->addModules( $out->getModules() );
 811                 $this->addModuleStyles( $out->getModuleStyles() );
 812                 $this->addJsConfigVars( $out->getJsConfigVars() );
 813
 814                 $this->mHeadItems = array_merge( $this->mHeadItems, $out->getHeadItemsArray() );
 815                 $this->mPreventClickjacking = $this->mPreventClickjacking || $out->getPreventClickjacking();
 816         }
 817
 818         /**
 819          * Add a tracking category, getting the title from a system message,
 820          * or print a debug message if the title is invalid.
 821          *
 822          * Any message used with this function should be registered so it will
 823          * show up on Special:TrackingCategories. Core messages should be added
 824          * to SpecialTrackingCategories::$coreTrackingCategories, and extensions
 825          * should add to "TrackingCategories" in their extension.json.
 826          *
 827          * @todo Migrate some code to TrackingCategories
 828          *
 829          * @param string $msg Message key
 830          * @param Title $title title of the page which is being tracked
 831          * @return bool Whether the addition was successful
 832          * @since 1.25
 833          */
 834         public function addTrackingCategory( $msg, $title ) {
 835                 if ( $title->isSpecialPage() ) {
 836                         wfDebug( __METHOD__ . ": Not adding tracking category $msg to special page!\n" );
 837                         return false;
 838                 }
 839
 840                 // Important to parse with correct title (T33469)
 841                 $cat = wfMessage( $msg )
 842                         ->title( $title )
 843                         ->inContentLanguage()
 844                         ->text();
 845
 846                 # Allow tracking categories to be disabled by setting them to "-"
 847                 if ( $cat === '-' ) {
 848                         return false;
 849                 }
 850
 851                 $containerCategory = Title::makeTitleSafe( NS_CATEGORY, $cat );
 852                 if ( $containerCategory ) {
 853                         $this->addCategory( $containerCategory->getDBkey(), $this->getProperty( 'defaultsort' ) ?: '' );
 854                         return true;
 855                 } else {
 856                         wfDebug( __METHOD__ . ": [[MediaWiki:$msg]] is not a valid title!\n" );
 857                         return false;
 858                 }
 859         }
 860
 861         /**
 862          * Override the title to be used for display
 863          *
 864          * @note this is assumed to have been validated
 865          * (check equal normalisation, etc.)
 866          *
 867          * @note this is expected to be safe HTML,
 868          * ready to be served to the client.
 869          *
 870          * @param string $text Desired title text
 871          */
 872         public function setDisplayTitle( $text ) {
 873                 $this->setTitleText( $text );
 874                 $this->setProperty( 'displaytitle', $text );
 875         }
 876
 877         /**
 878          * Get the title to be used for display.
 879          *
 880          * As per the contract of setDisplayTitle(), this is safe HTML,
 881          * ready to be served to the client.
 882          *
 883          * @return string HTML
 884          */
 885         public function getDisplayTitle() {
 886                 $t = $this->getTitleText();
 887                 if ( $t === '' ) {
 888                         return false;
 889                 }
 890                 return $t;
 891         }
 892
 893         /**
 894          * Fairly generic flag setter thingy.
 895          * @param string $flag
 896          */
 897         public function setFlag( $flag ) {
 898                 $this->mFlags[$flag] = true;
 899         }
 900
 901         public function getFlag( $flag ) {
 902                 return isset( $this->mFlags[$flag] );
 903         }
 904
 905         /**
 906          * Set a property to be stored in the page_props database table.
 907          *
 908          * page_props is a key value store indexed by the page ID. This allows
 909          * the parser to set a property on a page which can then be quickly
 910          * retrieved given the page ID or via a DB join when given the page
 911          * title.
 912          *
 913          * Since 1.23, page_props are also indexed by numeric value, to allow
 914          * for efficient "top k" queries of pages wrt a given property.
 915          *
 916          * setProperty() is thus used to propagate properties from the parsed
 917          * page to request contexts other than a page view of the currently parsed
 918          * article.
 919          *
 920          * Some applications examples:
 921          *
 922          *   * To implement hidden categories, hiding pages from category listings
 923          *     by storing a property.
 924          *
 925          *   * Overriding the displayed article title (ParserOutput::setDisplayTitle()).
 926          *
 927          *   * To implement image tagging, for example displaying an icon on an
 928          *     image thumbnail to indicate that it is listed for deletion on
 929          *     Wikimedia Commons.
 930          *     This is not actually implemented, yet but would be pretty cool.
 931          *
 932          * @note Do not use setProperty() to set a property which is only used
 933          * in a context where the ParserOutput object itself is already available,
 934          * for example a normal page view. There is no need to save such a property
 935          * in the database since the text is already parsed. You can just hook
 936          * OutputPageParserOutput and get your data out of the ParserOutput object.
 937          *
 938          * If you are writing an extension where you want to set a property in the
 939          * parser which is used by an OutputPageParserOutput hook, you have to
 940          * associate the extension data directly with the ParserOutput object.
 941          * Since MediaWiki 1.21, you can use setExtensionData() to do this:
 942          *
 943          * @par Example:
 944          * @code
 945          *    $parser->getOutput()->setExtensionData( 'my_ext_foo', '...' );
 946          * @endcode
 947          *
 948          * And then later, in OutputPageParserOutput or similar:
 949          *
 950          * @par Example:
 951          * @code
 952          *    $output->getExtensionData( 'my_ext_foo' );
 953          * @endcode
 954          *
 955          * In MediaWiki 1.20 and older, you have to use a custom member variable
 956          * within the ParserOutput object:
 957          *
 958          * @par Example:
 959          * @code
 960          *    $parser->getOutput()->my_ext_foo = '...';
 961          * @endcode
 962          * @param string $name
 963          * @param mixed $value
 964          */
 965         public function setProperty( $name, $value ) {
 966                 $this->mProperties[$name] = $value;
 967         }
 968
 969         /**
 970          * @param string $name The property name to look up.
 971          *
 972          * @return mixed|bool The value previously set using setProperty(). False if null or no value
 973          * was set for the given property name.
 974          *
 975          * @note You need to use getProperties() to check for boolean and null properties.
 976          */
 977         public function getProperty( $name ) {
 978                 return $this->mProperties[$name] ?? false;
 979         }
 980
 981         public function unsetProperty( $name ) {
 982                 unset( $this->mProperties[$name] );
 983         }
 984
 985         public function getProperties() {
 986                 if ( !isset( $this->mProperties ) ) {
 987                         $this->mProperties = [];
 988                 }
 989                 return $this->mProperties;
 990         }
 991
 992         /**
 993          * Returns the options from its ParserOptions which have been taken
 994          * into account to produce this output.
 995          * @return string[]
 996          */
 997         public function getUsedOptions() {
 998                 if ( !isset( $this->mAccessedOptions ) ) {
 999                         return [];
1000                 }
1001                 return array_keys( $this->mAccessedOptions );
1002         }
1003
1004         /**
1005          * Tags a parser option for use in the cache key for this parser output.
1006          * Registered as a watcher at ParserOptions::registerWatcher() by Parser::clearState().
1007          * The information gathered here is available via getUsedOptions(),
1008          * and is used by ParserCache::save().
1009          *
1010          * @see ParserCache::getKey
1011          * @see ParserCache::save
1012          * @see ParserOptions::addExtraKey
1013          * @see ParserOptions::optionsHash
1014          * @param string $option
1015          */
1016         public function recordOption( $option ) {
1017                 $this->mAccessedOptions[$option] = true;
1018         }
1019
1020         /**
1021          * Attaches arbitrary data to this ParserObject. This can be used to store some information in
1022          * the ParserOutput object for later use during page output. The data will be cached along with
1023          * the ParserOutput object, but unlike data set using setProperty(), it is not recorded in the
1024          * database.
1025          *
1026          * This method is provided to overcome the unsafe practice of attaching extra information to a
1027          * ParserObject by directly assigning member variables.
1028          *
1029          * To use setExtensionData() to pass extension information from a hook inside the parser to a
1030          * hook in the page output, use this in the parser hook:
1031          *
1032          * @par Example:
1033          * @code
1034          *    $parser->getOutput()->setExtensionData( 'my_ext_foo', '...' );
1035          * @endcode
1036          *
1037          * And then later, in OutputPageParserOutput or similar:
1038          *
1039          * @par Example:
1040          * @code
1041          *    $output->getExtensionData( 'my_ext_foo' );
1042          * @endcode
1043          *
1044          * In MediaWiki 1.20 and older, you have to use a custom member variable
1045          * within the ParserOutput object:
1046          *
1047          * @par Example:
1048          * @code
1049          *    $parser->getOutput()->my_ext_foo = '...';
1050          * @endcode
1051          *
1052          * @since 1.21
1053          *
1054          * @param string $key The key for accessing the data. Extensions should take care to avoid
1055          *   conflicts in naming keys. It is suggested to use the extension's name as a prefix.
1056          *
1057          * @param mixed $value The value to set. Setting a value to null is equivalent to removing
1058          *   the value.
1059          */
1060         public function setExtensionData( $key, $value ) {
1061                 if ( $value === null ) {
1062                         unset( $this->mExtensionData[$key] );
1063                 } else {
1064                         $this->mExtensionData[$key] = $value;
1065                 }
1066         }
1067
1068         /**
1069          * Gets extensions data previously attached to this ParserOutput using setExtensionData().
1070          * Typically, such data would be set while parsing the page, e.g. by a parser function.
1071          *
1072          * @since 1.21
1073          *
1074          * @param string $key The key to look up.
1075          *
1076          * @return mixed|null The value previously set for the given key using setExtensionData()
1077          *         or null if no value was set for this key.
1078          */
1079         public function getExtensionData( $key ) {
1080                 return $this->mExtensionData[$key] ?? null;
1081         }
1082
1083         private static function getTimes( $clock = null ) {
1084                 $ret = [];
1085                 if ( !$clock || $clock === 'wall' ) {
1086                         $ret['wall'] = microtime( true );
1087                 }
1088                 if ( !$clock || $clock === 'cpu' ) {
1089                         $ru = wfGetRusage();
1090                         if ( $ru ) {
1091                                 $ret['cpu'] = $ru['ru_utime.tv_sec'] + $ru['ru_utime.tv_usec'] / 1e6;
1092                                 $ret['cpu'] += $ru['ru_stime.tv_sec'] + $ru['ru_stime.tv_usec'] / 1e6;
1093                         }
1094                 }
1095                 return $ret;
1096         }
1097
1098         /**
1099          * Resets the parse start timestamps for future calls to getTimeSinceStart()
1100          * @since 1.22
1101          */
1102         public function resetParseStartTime() {
1103                 $this->mParseStartTime = self::getTimes();
1104         }
1105
1106         /**
1107          * Returns the time since resetParseStartTime() was last called
1108          *
1109          * Clocks available are:
1110          *  - wall: Wall clock time
1111          *  - cpu: CPU time (requires getrusage)
1112          *
1113          * @since 1.22
1114          * @param string $clock
1115          * @return float|null
1116          */
1117         public function getTimeSinceStart( $clock ) {
1118                 if ( !isset( $this->mParseStartTime[$clock] ) ) {
1119                         return null;
1120                 }
1121
1122                 $end = self::getTimes( $clock );
1123                 return $end[$clock] - $this->mParseStartTime[$clock];
1124         }
1125
1126         /**
1127          * Sets parser limit report data for a key
1128          *
1129          * The key is used as the prefix for various messages used for formatting:
1130          *  - $key: The label for the field in the limit report
1131          *  - $key-value-text: Message used to format the value in the "NewPP limit
1132          *      report" HTML comment. If missing, uses $key-format.
1133          *  - $key-value-html: Message used to format the value in the preview
1134          *      limit report table. If missing, uses $key-format.
1135          *  - $key-value: Message used to format the value. If missing, uses "$1".
1136          *
1137          * Note that all values are interpreted as wikitext, and so should be
1138          * encoded with htmlspecialchars() as necessary, but should avoid complex
1139          * HTML for sanity of display in the "NewPP limit report" comment.
1140          *
1141          * @since 1.22
1142          * @param string $key Message key
1143          * @param mixed $value Appropriate for Message::params()
1144          */
1145         public function setLimitReportData( $key, $value ) {
1146                 $this->mLimitReportData[$key] = $value;
1147
1148                 if ( is_array( $value ) ) {
1149                         if ( array_keys( $value ) === [ 0, 1 ]
1150                                 && is_numeric( $value[0] )
1151                                 && is_numeric( $value[1] )
1152                         ) {
1153                                 $data = [ 'value' => $value[0], 'limit' => $value[1] ];
1154                         } else {
1155                                 $data = $value;
1156                         }
1157                 } else {
1158                         $data = $value;
1159                 }
1160
1161                 if ( strpos( $key, '-' ) ) {
1162                         list( $ns, $name ) = explode( '-', $key, 2 );
1163                         $this->mLimitReportJSData[$ns][$name] = $data;
1164                 } else {
1165                         $this->mLimitReportJSData[$key] = $data;
1166                 }
1167         }
1168
1169         /**
1170          * Check whether the cache TTL was lowered due to dynamic content
1171          *
1172          * When content is determined by more than hard state (e.g. page edits),
1173          * such as template/file transclusions based on the current timestamp or
1174          * extension tags that generate lists based on queries, this return true.
1175          *
1176          * @return bool
1177          * @since 1.25
1178          */
1179         public function hasDynamicContent() {
1180                 global $wgParserCacheExpireTime;
1181
1182                 return $this->getCacheExpiry() < $wgParserCacheExpireTime;
1183         }
1184
1185         /**
1186          * Get or set the prevent-clickjacking flag
1187          *
1188          * @since 1.24
1189          * @param bool|null $flag New flag value, or null to leave it unchanged
1190          * @return bool Old flag value
1191          */
1192         public function preventClickjacking( $flag = null ) {
1193                 return wfSetVar( $this->mPreventClickjacking, $flag );
1194         }
1195
1196         /**
1197          * Lower the runtime adaptive TTL to at most this value
1198          *
1199          * @param int $ttl
1200          * @since 1.28
1201          */
1202         public function updateRuntimeAdaptiveExpiry( $ttl ) {
1203                 $this->mMaxAdaptiveExpiry = min( $ttl, $this->mMaxAdaptiveExpiry );
1204                 $this->updateCacheExpiry( $ttl );
1205         }
1206
1207         /**
1208          * Call this when parsing is done to lower the TTL based on low parse times
1209          *
1210          * @since 1.28
1211          */
1212         public function finalizeAdaptiveCacheExpiry() {
1213                 if ( is_infinite( $this->mMaxAdaptiveExpiry ) ) {
1214                         return; // not set
1215                 }
1216
1217                 $runtime = $this->getTimeSinceStart( 'wall' );
1218                 if ( is_float( $runtime ) ) {
1219                         $slope = ( self::SLOW_AR_TTL - self::FAST_AR_TTL )
1220                                 / ( self::PARSE_SLOW_SEC - self::PARSE_FAST_SEC );
1221                         // SLOW_AR_TTL = PARSE_SLOW_SEC * $slope + $point
1222                         $point = self::SLOW_AR_TTL - self::PARSE_SLOW_SEC * $slope;
1223
1224                         $adaptiveTTL = min(
1225                                 max( $slope * $runtime + $point, self::MIN_AR_TTL ),
1226                                 $this->mMaxAdaptiveExpiry
1227                         );
1228                         $this->updateCacheExpiry( $adaptiveTTL );
1229                 }
1230         }
1231
1232         public function __sleep() {
1233                 return array_diff(
1234                         array_keys( get_object_vars( $this ) ),
1235                         [ 'mParseStartTime' ]
1236                 );
1237         }
1238
1239         /**
1240          * Merges internal metadata such as flags, accessed options, and profiling info
1241          * from $source into this ParserOutput. This should be used whenever the state of $source
1242          * has any impact on the state of this ParserOutput.
1243          *
1244          * @param ParserOutput $source
1245          */
1246         public function mergeInternalMetaDataFrom( ParserOutput $source ) {
1247                 $this->mOutputHooks = self::mergeList( $this->mOutputHooks, $source->getOutputHooks() );
1248                 $this->mWarnings = self::mergeMap( $this->mWarnings, $source->mWarnings ); // don't use getter
1249                 $this->mTimestamp = $this->useMaxValue( $this->mTimestamp, $source->getTimestamp() );
1250
1251                 if ( $this->mSpeculativeRevId && $source->mSpeculativeRevId
1252                         && $this->mSpeculativeRevId !== $source->mSpeculativeRevId
1253                 ) {
1254                         wfLogWarning(
1255                                 'Inconsistent speculative revision ID encountered while merging parser output!'
1256                         );
1257                 }
1258
1259                 $this->mSpeculativeRevId = $this->useMaxValue(
1260                         $this->mSpeculativeRevId,
1261                         $source->getSpeculativeRevIdUsed()
1262                 );
1263                 $this->mParseStartTime = $this->useEachMinValue(
1264                         $this->mParseStartTime,
1265                         $source->mParseStartTime
1266                 );
1267
1268                 $this->mFlags = self::mergeMap( $this->mFlags, $source->mFlags );
1269                 $this->mAccessedOptions = self::mergeMap( $this->mAccessedOptions, $source->mAccessedOptions );
1270
1271                 // TODO: maintain per-slot limit reports!
1272                 if ( empty( $this->mLimitReportData ) ) {
1273                         $this->mLimitReportData = $source->mLimitReportData;
1274                 }
1275                 if ( empty( $this->mLimitReportJSData ) ) {
1276                         $this->mLimitReportJSData = $source->mLimitReportJSData;
1277                 }
1278         }
1279
1280         /**
1281          * Merges HTML metadata such as head items, JS config vars, and HTTP cache control info
1282          * from $source into this ParserOutput. This should be used whenever the HTML in $source
1283          * has been somehow mered into the HTML of this ParserOutput.
1284          *
1285          * @param ParserOutput $source
1286          */
1287         public function mergeHtmlMetaDataFrom( ParserOutput $source ) {
1288                 // HTML and HTTP
1289                 $this->mHeadItems = self::mergeMixedList( $this->mHeadItems, $source->getHeadItems() );
1290                 $this->mModules = self::mergeList( $this->mModules, $source->getModules() );
1291                 $this->mModuleStyles = self::mergeList( $this->mModuleStyles, $source->getModuleStyles() );
1292                 $this->mJsConfigVars = self::mergeMap( $this->mJsConfigVars, $source->getJsConfigVars() );
1293                 $this->mMaxAdaptiveExpiry = min( $this->mMaxAdaptiveExpiry, $source->mMaxAdaptiveExpiry );
1294
1295                 // "noindex" always wins!
1296                 if ( $this->mIndexPolicy === 'noindex' || $source->mIndexPolicy === 'noindex' ) {
1297                         $this->mIndexPolicy = 'noindex';
1298                 } elseif ( $this->mIndexPolicy !== 'index' ) {
1299                         $this->mIndexPolicy = $source->mIndexPolicy;
1300                 }
1301
1302                 // Skin control
1303                 $this->mNewSection = $this->mNewSection || $source->getNewSection();
1304                 $this->mHideNewSection = $this->mHideNewSection || $source->getHideNewSection();
1305                 $this->mNoGallery = $this->mNoGallery || $source->getNoGallery();
1306                 $this->mEnableOOUI = $this->mEnableOOUI || $source->getEnableOOUI();
1307                 $this->mPreventClickjacking = $this->mPreventClickjacking || $source->preventClickjacking();
1308
1309                 // TODO: we'll have to be smarter about this!
1310                 $this->mSections = array_merge( $this->mSections, $source->getSections() );
1311                 $this->mTOCHTML .= $source->mTOCHTML;
1312
1313                 // XXX: we don't want to concatenate title text, so first write wins.
1314                 // We should use the first *modified* title text, but we don't have the original to check.
1315                 if ( $this->mTitleText === null || $this->mTitleText === '' ) {
1316                         $this->mTitleText = $source->mTitleText;
1317                 }
1318
1319                 // class names are stored in array keys
1320                 $this->mWrapperDivClasses = self::mergeMap(
1321                         $this->mWrapperDivClasses,
1322                         $source->mWrapperDivClasses
1323                 );
1324
1325                 // NOTE: last write wins, same as within one ParserOutput
1326                 $this->mIndicators = self::mergeMap( $this->mIndicators, $source->getIndicators() );
1327
1328                 // NOTE: include extension data in "tracking meta data" as well as "html meta data"!
1329                 // TODO: add a $mergeStrategy parameter to setExtensionData to allow different
1330                 // kinds of extension data to be merged in different ways.
1331                 $this->mExtensionData = self::mergeMap(
1332                         $this->mExtensionData,
1333                         $source->mExtensionData
1334                 );
1335         }
1336
1337         /**
1338          * Merges dependency tracking metadata such as backlinks, images used, and extension data
1339          * from $source into this ParserOutput. This allows dependency tracking to be done for the
1340          * combined output of multiple content slots.
1341          *
1342          * @param ParserOutput $source
1343          */
1344         public function mergeTrackingMetaDataFrom( ParserOutput $source ) {
1345                 $this->mLanguageLinks = self::mergeList( $this->mLanguageLinks, $source->getLanguageLinks() );
1346                 $this->mCategories = self::mergeMap( $this->mCategories, $source->getCategories() );
1347                 $this->mLinks = self::merge2D( $this->mLinks, $source->getLinks() );
1348                 $this->mTemplates = self::merge2D( $this->mTemplates, $source->getTemplates() );
1349                 $this->mTemplateIds = self::merge2D( $this->mTemplateIds, $source->getTemplateIds() );
1350                 $this->mImages = self::mergeMap( $this->mImages, $source->getImages() );
1351                 $this->mFileSearchOptions = self::mergeMap(
1352                         $this->mFileSearchOptions,
1353                         $source->getFileSearchOptions()
1354                 );
1355                 $this->mExternalLinks = self::mergeMap( $this->mExternalLinks, $source->getExternalLinks() );
1356                 $this->mInterwikiLinks = self::merge2D(
1357                         $this->mInterwikiLinks,
1358                         $source->getInterwikiLinks()
1359                 );
1360
1361                 // TODO: add a $mergeStrategy parameter to setProperty to allow different
1362                 // kinds of properties to be merged in different ways.
1363                 $this->mProperties = self::mergeMap( $this->mProperties, $source->getProperties() );
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         private static function mergeMixedList( array $a, array $b ) {
1375                 return array_unique( array_merge( $a, $b ), SORT_REGULAR );
1376         }
1377
1378         private static function mergeList( array $a, array $b ) {
1379                 return array_values( array_unique( array_merge( $a, $b ), SORT_REGULAR ) );
1380         }
1381
1382         private static function mergeMap( array $a, array $b ) {
1383                 return array_replace( $a, $b );
1384         }
1385
1386         private static function merge2D( array $a, array $b ) {
1387                 $values = [];
1388                 $keys = array_merge( array_keys( $a ), array_keys( $b ) );
1389
1390                 foreach ( $keys as $k ) {
1391                         if ( empty( $a[$k] ) ) {
1392                                 $values[$k] = $b[$k];
1393                         } elseif ( empty( $b[$k] ) ) {
1394                                 $values[$k] = $a[$k];
1395                         } elseif ( is_array( $a[$k] ) && is_array( $b[$k] ) ) {
1396                                 $values[$k] = array_replace( $a[$k], $b[$k] );
1397                         } else {
1398                                 $values[$k] = $b[$k];
1399                         }
1400                 }
1401
1402                 return $values;
1403         }
1404
1405         private static function useEachMinValue( array $a, array $b ) {
1406                 $values = [];
1407                 $keys = array_merge( array_keys( $a ), array_keys( $b ) );
1408
1409                 foreach ( $keys as $k ) {
1410                         if ( is_array( $a[$k] ?? null ) && is_array( $b[$k] ?? null ) ) {
1411                                 $values[$k] = self::useEachMinValue( $a[$k], $b[$k] );
1412                         } else {
1413                                 $values[$k] = self::useMinValue( $a[$k] ?? null, $b[$k] ?? null );
1414                         }
1415                 }
1416
1417                 return $values;
1418         }
1419
1420         private static function useMinValue( $a, $b ) {
1421                 if ( $a === null ) {
1422                         return $b;
1423                 }
1424
1425                 if ( $b === null ) {
1426                         return $a;
1427                 }
1428
1429                 return min( $a, $b );
1430         }
1431
1432         private static function useMaxValue( $a, $b ) {
1433                 if ( $a === null ) {
1434                         return $b;
1435                 }
1436
1437                 if ( $b === null ) {
1438                         return $a;
1439                 }
1440
1441                 return max( $a, $b );
1442         }
1443
1444 }