includes/OutputPage.php

   1 <?php
   2 /**
   3  * Preparation for the final page rendering.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 use MediaWiki\Linker\LinkTarget;
  24 use MediaWiki\Logger\LoggerFactory;
  25 use MediaWiki\MediaWikiServices;
  26 use MediaWiki\Session\SessionManager;
  27 use Wikimedia\RelPath;
  28 use Wikimedia\WrappedString;
  29 use Wikimedia\WrappedStringList;
  30
  31 /**
  32  * This class should be covered by a general architecture document which does
  33  * not exist as of January 2011.  This is one of the Core classes and should
  34  * be read at least once by any new developers.
  35  *
  36  * This class is used to prepare the final rendering. A skin is then
  37  * applied to the output parameters (links, javascript, html, categories ...).
  38  *
  39  * @todo FIXME: Another class handles sending the whole page to the client.
  40  *
  41  * Some comments comes from a pairing session between Zak Greant and Antoine Musso
  42  * in November 2010.
  43  *
  44  * @todo document
  45  */
  46 class OutputPage extends ContextSource {
  47         /** @var array Should be private. Used with addMeta() which adds "<meta>" */
  48         protected $mMetatags = [];
  49
  50         /** @var array */
  51         protected $mLinktags = [];
  52
  53         /** @var bool */
  54         protected $mCanonicalUrl = false;
  55
  56         /**
  57          * @var string Should be private - has getter and setter. Contains
  58          *   the HTML title */
  59         public $mPagetitle = '';
  60
  61         /**
  62          * @var string Contains all of the "<body>" content. Should be private we
  63          *   got set/get accessors and the append() method.
  64          */
  65         public $mBodytext = '';
  66
  67         /** @var string Stores contents of "<title>" tag */
  68         private $mHTMLtitle = '';
  69
  70         /**
  71          * @var bool Is the displayed content related to the source of the
  72          *   corresponding wiki article.
  73          */
  74         private $mIsarticle = false;
  75
  76         /** @var bool Stores "article flag" toggle. */
  77         private $mIsArticleRelated = true;
  78
  79         /**
  80          * @var bool We have to set isPrintable(). Some pages should
  81          * never be printed (ex: redirections).
  82          */
  83         private $mPrintable = false;
  84
  85         /**
  86          * @var array Contains the page subtitle. Special pages usually have some
  87          *   links here. Don't confuse with site subtitle added by skins.
  88          */
  89         private $mSubtitle = [];
  90
  91         /** @var string */
  92         public $mRedirect = '';
  93
  94         /** @var int */
  95         protected $mStatusCode;
  96
  97         /**
  98          * @var string Used for sending cache control.
  99          *   The whole caching system should probably be moved into its own class.
 100          */
 101         protected $mLastModified = '';
 102
 103         /** @var array */
 104         protected $mCategoryLinks = [];
 105
 106         /** @var array */
 107         protected $mCategories = [
 108                 'hidden' => [],
 109                 'normal' => [],
 110         ];
 111
 112         /** @var array */
 113         protected $mIndicators = [];
 114
 115         /** @var array Array of Interwiki Prefixed (non DB key) Titles (e.g. 'fr:Test page') */
 116         private $mLanguageLinks = [];
 117
 118         /**
 119          * Used for JavaScript (predates ResourceLoader)
 120          * @todo We should split JS / CSS.
 121          * mScripts content is inserted as is in "<head>" by Skin. This might
 122          * contain either a link to a stylesheet or inline CSS.
 123          */
 124         private $mScripts = '';
 125
 126         /** @var string Inline CSS styles. Use addInlineStyle() sparingly */
 127         protected $mInlineStyles = '';
 128
 129         /**
 130          * @var string Used by skin template.
 131          * Example: $tpl->set( 'displaytitle', $out->mPageLinkTitle );
 132          */
 133         public $mPageLinkTitle = '';
 134
 135         /** @var array Array of elements in "<head>". Parser might add its own headers! */
 136         protected $mHeadItems = [];
 137
 138         /** @var array Additional <body> classes; there are also <body> classes from other sources */
 139         protected $mAdditionalBodyClasses = [];
 140
 141         /** @var array */
 142         protected $mModules = [];
 143
 144         /** @var array */
 145         protected $mModuleScripts = [];
 146
 147         /** @var array */
 148         protected $mModuleStyles = [];
 149
 150         /** @var ResourceLoader */
 151         protected $mResourceLoader;
 152
 153         /** @var ResourceLoaderClientHtml */
 154         private $rlClient;
 155
 156         /** @var ResourceLoaderContext */
 157         private $rlClientContext;
 158
 159         /** @var array */
 160         private $rlExemptStyleModules;
 161
 162         /** @var array */
 163         protected $mJsConfigVars = [];
 164
 165         /** @var array */
 166         protected $mTemplateIds = [];
 167
 168         /** @var array */
 169         protected $mImageTimeKeys = [];
 170
 171         /** @var string */
 172         public $mRedirectCode = '';
 173
 174         protected $mFeedLinksAppendQuery = null;
 175
 176         /** @var array
 177          * What level of 'untrustworthiness' is allowed in CSS/JS modules loaded on this page?
 178          * @see ResourceLoaderModule::$origin
 179          * ResourceLoaderModule::ORIGIN_ALL is assumed unless overridden;
 180          */
 181         protected $mAllowedModules = [
 182                 ResourceLoaderModule::TYPE_COMBINED => ResourceLoaderModule::ORIGIN_ALL,
 183         ];
 184
 185         /** @var bool Whether output is disabled.  If this is true, the 'output' method will do nothing. */
 186         protected $mDoNothing = false;
 187
 188         // Parser related.
 189
 190         /** @var int */
 191         protected $mContainsNewMagic = 0;
 192
 193         /**
 194          * lazy initialised, use parserOptions()
 195          * @var ParserOptions
 196          */
 197         protected $mParserOptions = null;
 198
 199         /**
 200          * Handles the Atom / RSS links.
 201          * We probably only support Atom in 2011.
 202          * @see $wgAdvertisedFeedTypes
 203          */
 204         private $mFeedLinks = [];
 205
 206         // Gwicke work on squid caching? Roughly from 2003.
 207         protected $mEnableClientCache = true;
 208
 209         /** @var bool Flag if output should only contain the body of the article. */
 210         private $mArticleBodyOnly = false;
 211
 212         /** @var bool */
 213         protected $mNewSectionLink = false;
 214
 215         /** @var bool */
 216         protected $mHideNewSectionLink = false;
 217
 218         /**
 219          * @var bool Comes from the parser. This was probably made to load CSS/JS
 220          * only if we had "<gallery>". Used directly in CategoryPage.php.
 221          * Looks like ResourceLoader can replace this.
 222          */
 223         public $mNoGallery = false;
 224
 225         /** @var string */
 226         private $mPageTitleActionText = '';
 227
 228         /** @var int Cache stuff. Looks like mEnableClientCache */
 229         protected $mCdnMaxage = 0;
 230         /** @var int Upper limit on mCdnMaxage */
 231         protected $mCdnMaxageLimit = INF;
 232
 233         /**
 234          * @var bool Controls if anti-clickjacking / frame-breaking headers will
 235          * be sent. This should be done for pages where edit actions are possible.
 236          * Setters: $this->preventClickjacking() and $this->allowClickjacking().
 237          */
 238         protected $mPreventClickjacking = true;
 239
 240         /** @var int To include the variable {{REVISIONID}} */
 241         private $mRevisionId = null;
 242
 243         /** @var string */
 244         private $mRevisionTimestamp = null;
 245
 246         /** @var array */
 247         protected $mFileVersion = null;
 248
 249         /**
 250          * @var array An array of stylesheet filenames (relative from skins path),
 251          * with options for CSS media, IE conditions, and RTL/LTR direction.
 252          * For internal use; add settings in the skin via $this->addStyle()
 253          *
 254          * Style again! This seems like a code duplication since we already have
 255          * mStyles. This is what makes Open Source amazing.
 256          */
 257         protected $styles = [];
 258
 259         private $mIndexPolicy = 'index';
 260         private $mFollowPolicy = 'follow';
 261         private $mVaryHeader = [
 262                 'Accept-Encoding' => [ 'match=gzip' ],
 263         ];
 264
 265         /**
 266          * If the current page was reached through a redirect, $mRedirectedFrom contains the Title
 267          * of the redirect.
 268          *
 269          * @var Title
 270          */
 271         private $mRedirectedFrom = null;
 272
 273         /**
 274          * Additional key => value data
 275          */
 276         private $mProperties = [];
 277
 278         /**
 279          * @var string|null ResourceLoader target for load.php links. If null, will be omitted
 280          */
 281         private $mTarget = null;
 282
 283         /**
 284          * @var bool Whether parser output contains a table of contents
 285          */
 286         private $mEnableTOC = false;
 287
 288         /**
 289          * @var string|null The URL to send in a <link> element with rel=license
 290          */
 291         private $copyrightUrl;
 292
 293         /** @var array Profiling data */
 294         private $limitReportJSData = [];
 295
 296         /** @var array Map Title to Content */
 297         private $contentOverrides = [];
 298
 299         /** @var callable[] */
 300         private $contentOverrideCallbacks = [];
 301
 302         /**
 303          * Link: header contents
 304          */
 305         private $mLinkHeader = [];
 306
 307         /**
 308          * Constructor for OutputPage. This should not be called directly.
 309          * Instead a new RequestContext should be created and it will implicitly create
 310          * a OutputPage tied to that context.
 311          * @param IContextSource $context
 312          */
 313         function __construct( IContextSource $context ) {
 314                 $this->setContext( $context );
 315         }
 316
 317         /**
 318          * Redirect to $url rather than displaying the normal page
 319          *
 320          * @param string $url
 321          * @param string $responsecode HTTP status code
 322          */
 323         public function redirect( $url, $responsecode = '302' ) {
 324                 # Strip newlines as a paranoia check for header injection in PHP<5.1.2
 325                 $this->mRedirect = str_replace( "\n", '', $url );
 326                 $this->mRedirectCode = $responsecode;
 327         }
 328
 329         /**
 330          * Get the URL to redirect to, or an empty string if not redirect URL set
 331          *
 332          * @return string
 333          */
 334         public function getRedirect() {
 335                 return $this->mRedirect;
 336         }
 337
 338         /**
 339          * Set the copyright URL to send with the output.
 340          * Empty string to omit, null to reset.
 341          *
 342          * @since 1.26
 343          *
 344          * @param string|null $url
 345          */
 346         public function setCopyrightUrl( $url ) {
 347                 $this->copyrightUrl = $url;
 348         }
 349
 350         /**
 351          * Set the HTTP status code to send with the output.
 352          *
 353          * @param int $statusCode
 354          */
 355         public function setStatusCode( $statusCode ) {
 356                 $this->mStatusCode = $statusCode;
 357         }
 358
 359         /**
 360          * Add a new "<meta>" tag
 361          * To add an http-equiv meta tag, precede the name with "http:"
 362          *
 363          * @param string $name Name of the meta tag
 364          * @param string $val Value of the meta tag
 365          */
 366         function addMeta( $name, $val ) {
 367                 array_push( $this->mMetatags, [ $name, $val ] );
 368         }
 369
 370         /**
 371          * Returns the current <meta> tags
 372          *
 373          * @since 1.25
 374          * @return array
 375          */
 376         public function getMetaTags() {
 377                 return $this->mMetatags;
 378         }
 379
 380         /**
 381          * Add a new \<link\> tag to the page header.
 382          *
 383          * Note: use setCanonicalUrl() for rel=canonical.
 384          *
 385          * @param array $linkarr Associative array of attributes.
 386          */
 387         function addLink( array $linkarr ) {
 388                 array_push( $this->mLinktags, $linkarr );
 389         }
 390
 391         /**
 392          * Returns the current <link> tags
 393          *
 394          * @since 1.25
 395          * @return array
 396          */
 397         public function getLinkTags() {
 398                 return $this->mLinktags;
 399         }
 400
 401         /**
 402          * Add a new \<link\> with "rel" attribute set to "meta"
 403          *
 404          * @param array $linkarr Associative array mapping attribute names to their
 405          *                 values, both keys and values will be escaped, and the
 406          *                 "rel" attribute will be automatically added
 407          */
 408         function addMetadataLink( array $linkarr ) {
 409                 $linkarr['rel'] = $this->getMetadataAttribute();
 410                 $this->addLink( $linkarr );
 411         }
 412
 413         /**
 414          * Set the URL to be used for the <link rel=canonical>. This should be used
 415          * in preference to addLink(), to avoid duplicate link tags.
 416          * @param string $url
 417          */
 418         function setCanonicalUrl( $url ) {
 419                 $this->mCanonicalUrl = $url;
 420         }
 421
 422         /**
 423          * Returns the URL to be used for the <link rel=canonical> if
 424          * one is set.
 425          *
 426          * @since 1.25
 427          * @return bool|string
 428          */
 429         public function getCanonicalUrl() {
 430                 return $this->mCanonicalUrl;
 431         }
 432
 433         /**
 434          * Get the value of the "rel" attribute for metadata links
 435          *
 436          * @return string
 437          */
 438         public function getMetadataAttribute() {
 439                 # note: buggy CC software only reads first "meta" link
 440                 static $haveMeta = false;
 441                 if ( $haveMeta ) {
 442                         return 'alternate meta';
 443                 } else {
 444                         $haveMeta = true;
 445                         return 'meta';
 446                 }
 447         }
 448
 449         /**
 450          * Add raw HTML to the list of scripts (including \<script\> tag, etc.)
 451          * Internal use only. Use OutputPage::addModules() or OutputPage::addJsConfigVars()
 452          * if possible.
 453          *
 454          * @param string $script Raw HTML
 455          */
 456         function addScript( $script ) {
 457                 $this->mScripts .= $script;
 458         }
 459
 460         /**
 461          * Add a JavaScript file out of skins/common, or a given relative path.
 462          * Internal use only. Use OutputPage::addModules() if possible.
 463          *
 464          * @param string $file Filename in skins/common or complete on-server path
 465          *              (/foo/bar.js)
 466          * @param string $version Style version of the file. Defaults to $wgStyleVersion
 467          */
 468         public function addScriptFile( $file, $version = null ) {
 469                 // See if $file parameter is an absolute URL or begins with a slash
 470                 if ( substr( $file, 0, 1 ) == '/' || preg_match( '#^[a-z]*://#i', $file ) ) {
 471                         $path = $file;
 472                 } else {
 473                         $path = $this->getConfig()->get( 'StylePath' ) . "/common/{$file}";
 474                 }
 475                 if ( is_null( $version ) ) {
 476                         $version = $this->getConfig()->get( 'StyleVersion' );
 477                 }
 478                 $this->addScript( Html::linkedScript( wfAppendQuery( $path, $version ) ) );
 479         }
 480
 481         /**
 482          * Add a self-contained script tag with the given contents
 483          * Internal use only. Use OutputPage::addModules() if possible.
 484          *
 485          * @param string $script JavaScript text, no script tags
 486          */
 487         public function addInlineScript( $script ) {
 488                 $this->mScripts .= Html::inlineScript( $script );
 489         }
 490
 491         /**
 492          * Filter an array of modules to remove insufficiently trustworthy members, and modules
 493          * which are no longer registered (eg a page is cached before an extension is disabled)
 494          * @param array $modules
 495          * @param string|null $position Unused
 496          * @param string $type
 497          * @return array
 498          */
 499         protected function filterModules( array $modules, $position = null,
 500                 $type = ResourceLoaderModule::TYPE_COMBINED
 501         ) {
 502                 $resourceLoader = $this->getResourceLoader();
 503                 $filteredModules = [];
 504                 foreach ( $modules as $val ) {
 505                         $module = $resourceLoader->getModule( $val );
 506                         if ( $module instanceof ResourceLoaderModule
 507                                 && $module->getOrigin() <= $this->getAllowedModules( $type )
 508                         ) {
 509                                 if ( $this->mTarget && !in_array( $this->mTarget, $module->getTargets() ) ) {
 510                                         $this->warnModuleTargetFilter( $module->getName() );
 511                                         continue;
 512                                 }
 513                                 $filteredModules[] = $val;
 514                         }
 515                 }
 516                 return $filteredModules;
 517         }
 518
 519         private function warnModuleTargetFilter( $moduleName ) {
 520                 static $warnings = [];
 521                 if ( isset( $warnings[$this->mTarget][$moduleName] ) ) {
 522                         return;
 523                 }
 524                 $warnings[$this->mTarget][$moduleName] = true;
 525                 $this->getResourceLoader()->getLogger()->debug(
 526                         'Module "{module}" not loadable on target "{target}".',
 527                         [
 528                                 'module' => $moduleName,
 529                                 'target' => $this->mTarget,
 530                         ]
 531                 );
 532         }
 533
 534         /**
 535          * Get the list of modules to include on this page
 536          *
 537          * @param bool $filter Whether to filter out insufficiently trustworthy modules
 538          * @param string|null $position Unused
 539          * @param string $param
 540          * @param string $type
 541          * @return array Array of module names
 542          */
 543         public function getModules( $filter = false, $position = null, $param = 'mModules',
 544                 $type = ResourceLoaderModule::TYPE_COMBINED
 545         ) {
 546                 $modules = array_values( array_unique( $this->$param ) );
 547                 return $filter
 548                         ? $this->filterModules( $modules, null, $type )
 549                         : $modules;
 550         }
 551
 552         /**
 553          * Add one or more modules recognized by ResourceLoader. Modules added
 554          * through this function will be loaded by ResourceLoader when the
 555          * page loads.
 556          *
 557          * @param string|array $modules Module name (string) or array of module names
 558          */
 559         public function addModules( $modules ) {
 560                 $this->mModules = array_merge( $this->mModules, (array)$modules );
 561         }
 562
 563         /**
 564          * Get the list of module JS to include on this page
 565          *
 566          * @param bool $filter
 567          * @param string|null $position Unused
 568          * @return array Array of module names
 569          */
 570         public function getModuleScripts( $filter = false, $position = null ) {
 571                 return $this->getModules( $filter, null, 'mModuleScripts',
 572                         ResourceLoaderModule::TYPE_SCRIPTS
 573                 );
 574         }
 575
 576         /**
 577          * Add only JS of one or more modules recognized by ResourceLoader. Module
 578          * scripts added through this function will be loaded by ResourceLoader when
 579          * the page loads.
 580          *
 581          * @param string|array $modules Module name (string) or array of module names
 582          */
 583         public function addModuleScripts( $modules ) {
 584                 $this->mModuleScripts = array_merge( $this->mModuleScripts, (array)$modules );
 585         }
 586
 587         /**
 588          * Get the list of module CSS to include on this page
 589          *
 590          * @param bool $filter
 591          * @param string|null $position Unused
 592          * @return array Array of module names
 593          */
 594         public function getModuleStyles( $filter = false, $position = null ) {
 595                 return $this->getModules( $filter, null, 'mModuleStyles',
 596                         ResourceLoaderModule::TYPE_STYLES
 597                 );
 598         }
 599
 600         /**
 601          * Add only CSS of one or more modules recognized by ResourceLoader.
 602          *
 603          * Module styles added through this function will be added using standard link CSS
 604          * tags, rather than as a combined Javascript and CSS package. Thus, they will
 605          * load when JavaScript is disabled (unless CSS also happens to be disabled).
 606          *
 607          * @param string|array $modules Module name (string) or array of module names
 608          */
 609         public function addModuleStyles( $modules ) {
 610                 $this->mModuleStyles = array_merge( $this->mModuleStyles, (array)$modules );
 611         }
 612
 613         /**
 614          * @return null|string ResourceLoader target
 615          */
 616         public function getTarget() {
 617                 return $this->mTarget;
 618         }
 619
 620         /**
 621          * Sets ResourceLoader target for load.php links. If null, will be omitted
 622          *
 623          * @param string|null $target
 624          */
 625         public function setTarget( $target ) {
 626                 $this->mTarget = $target;
 627         }
 628
 629         /**
 630          * Add a mapping from a LinkTarget to a Content, for things like page preview.
 631          * @see self::addContentOverrideCallback()
 632          * @since 1.32
 633          * @param LinkTarget $target
 634          * @param Content $content
 635          */
 636         public function addContentOverride( LinkTarget $target, Content $content ) {
 637                 if ( !$this->contentOverrides ) {
 638                         // Register a callback for $this->contentOverrides on the first call
 639                         $this->addContentOverrideCallback( function ( LinkTarget $target ) {
 640                                 $key = $target->getNamespace() . ':' . $target->getDBkey();
 641                                 return isset( $this->contentOverrides[$key] )
 642                                         ? $this->contentOverrides[$key]
 643                                         : null;
 644                         } );
 645                 }
 646
 647                 $key = $target->getNamespace() . ':' . $target->getDBkey();
 648                 $this->contentOverrides[$key] = $content;
 649         }
 650
 651         /**
 652          * Add a callback for mapping from a Title to a Content object, for things
 653          * like page preview.
 654          * @see ResourceLoaderContext::getContentOverrideCallback()
 655          * @since 1.32
 656          * @param callable $callback
 657          */
 658         public function addContentOverrideCallback( callable $callback ) {
 659                 $this->contentOverrideCallbacks[] = $callback;
 660         }
 661
 662         /**
 663          * Get an array of head items
 664          *
 665          * @return array
 666          */
 667         function getHeadItemsArray() {
 668                 return $this->mHeadItems;
 669         }
 670
 671         /**
 672          * Add or replace a head item to the output
 673          *
 674          * Whenever possible, use more specific options like ResourceLoader modules,
 675          * OutputPage::addLink(), OutputPage::addMetaLink() and OutputPage::addFeedLink()
 676          * Fallback options for those are: OutputPage::addStyle, OutputPage::addScript(),
 677          * OutputPage::addInlineScript() and OutputPage::addInlineStyle()
 678          * This would be your very LAST fallback.
 679          *
 680          * @param string $name Item name
 681          * @param string $value Raw HTML
 682          */
 683         public function addHeadItem( $name, $value ) {
 684                 $this->mHeadItems[$name] = $value;
 685         }
 686
 687         /**
 688          * Add one or more head items to the output
 689          *
 690          * @since 1.28
 691          * @param string|string[] $values Raw HTML
 692          */
 693         public function addHeadItems( $values ) {
 694                 $this->mHeadItems = array_merge( $this->mHeadItems, (array)$values );
 695         }
 696
 697         /**
 698          * Check if the header item $name is already set
 699          *
 700          * @param string $name Item name
 701          * @return bool
 702          */
 703         public function hasHeadItem( $name ) {
 704                 return isset( $this->mHeadItems[$name] );
 705         }
 706
 707         /**
 708          * Add a class to the <body> element
 709          *
 710          * @since 1.30
 711          * @param string|string[] $classes One or more classes to add
 712          */
 713         public function addBodyClasses( $classes ) {
 714                 $this->mAdditionalBodyClasses = array_merge( $this->mAdditionalBodyClasses, (array)$classes );
 715         }
 716
 717         /**
 718          * Set whether the output should only contain the body of the article,
 719          * without any skin, sidebar, etc.
 720          * Used e.g. when calling with "action=render".
 721          *
 722          * @param bool $only Whether to output only the body of the article
 723          */
 724         public function setArticleBodyOnly( $only ) {
 725                 $this->mArticleBodyOnly = $only;
 726         }
 727
 728         /**
 729          * Return whether the output will contain only the body of the article
 730          *
 731          * @return bool
 732          */
 733         public function getArticleBodyOnly() {
 734                 return $this->mArticleBodyOnly;
 735         }
 736
 737         /**
 738          * Set an additional output property
 739          * @since 1.21
 740          *
 741          * @param string $name
 742          * @param mixed $value
 743          */
 744         public function setProperty( $name, $value ) {
 745                 $this->mProperties[$name] = $value;
 746         }
 747
 748         /**
 749          * Get an additional output property
 750          * @since 1.21
 751          *
 752          * @param string $name
 753          * @return mixed Property value or null if not found
 754          */
 755         public function getProperty( $name ) {
 756                 if ( isset( $this->mProperties[$name] ) ) {
 757                         return $this->mProperties[$name];
 758                 } else {
 759                         return null;
 760                 }
 761         }
 762
 763         /**
 764          * checkLastModified tells the client to use the client-cached page if
 765          * possible. If successful, the OutputPage is disabled so that
 766          * any future call to OutputPage->output() have no effect.
 767          *
 768          * Side effect: sets mLastModified for Last-Modified header
 769          *
 770          * @param string $timestamp
 771          *
 772          * @return bool True if cache-ok headers was sent.
 773          */
 774         public function checkLastModified( $timestamp ) {
 775                 if ( !$timestamp || $timestamp == '19700101000000' ) {
 776                         wfDebug( __METHOD__ . ": CACHE DISABLED, NO TIMESTAMP\n" );
 777                         return false;
 778                 }
 779                 $config = $this->getConfig();
 780                 if ( !$config->get( 'CachePages' ) ) {
 781                         wfDebug( __METHOD__ . ": CACHE DISABLED\n" );
 782                         return false;
 783                 }
 784
 785                 $timestamp = wfTimestamp( TS_MW, $timestamp );
 786                 $modifiedTimes = [
 787                         'page' => $timestamp,
 788                         'user' => $this->getUser()->getTouched(),
 789                         'epoch' => $config->get( 'CacheEpoch' )
 790                 ];
 791                 if ( $config->get( 'UseSquid' ) ) {
 792                         $modifiedTimes['sepoch'] = wfTimestamp( TS_MW, $this->getCdnCacheEpoch(
 793                                 time(),
 794                                 $config->get( 'SquidMaxage' )
 795                         ) );
 796                 }
 797                 Hooks::run( 'OutputPageCheckLastModified', [ &$modifiedTimes, $this ] );
 798
 799                 $maxModified = max( $modifiedTimes );
 800                 $this->mLastModified = wfTimestamp( TS_RFC2822, $maxModified );
 801
 802                 $clientHeader = $this->getRequest()->getHeader( 'If-Modified-Since' );
 803                 if ( $clientHeader === false ) {
 804                         wfDebug( __METHOD__ . ": client did not send If-Modified-Since header", 'private' );
 805                         return false;
 806                 }
 807
 808                 # IE sends sizes after the date like this:
 809                 # Wed, 20 Aug 2003 06:51:19 GMT; length=5202
 810                 # this breaks strtotime().
 811                 $clientHeader = preg_replace( '/;.*$/', '', $clientHeader );
 812
 813                 Wikimedia\suppressWarnings(); // E_STRICT system time bitching
 814                 $clientHeaderTime = strtotime( $clientHeader );
 815                 Wikimedia\restoreWarnings();
 816                 if ( !$clientHeaderTime ) {
 817                         wfDebug( __METHOD__
 818                                 . ": unable to parse the client's If-Modified-Since header: $clientHeader\n" );
 819                         return false;
 820                 }
 821                 $clientHeaderTime = wfTimestamp( TS_MW, $clientHeaderTime );
 822
 823                 # Make debug info
 824                 $info = '';
 825                 foreach ( $modifiedTimes as $name => $value ) {
 826                         if ( $info !== '' ) {
 827                                 $info .= ', ';
 828                         }
 829                         $info .= "$name=" . wfTimestamp( TS_ISO_8601, $value );
 830                 }
 831
 832                 wfDebug( __METHOD__ . ": client sent If-Modified-Since: " .
 833                         wfTimestamp( TS_ISO_8601, $clientHeaderTime ), 'private' );
 834                 wfDebug( __METHOD__ . ": effective Last-Modified: " .
 835                         wfTimestamp( TS_ISO_8601, $maxModified ), 'private' );
 836                 if ( $clientHeaderTime < $maxModified ) {
 837                         wfDebug( __METHOD__ . ": STALE, $info", 'private' );
 838                         return false;
 839                 }
 840
 841                 # Not modified
 842                 # Give a 304 Not Modified response code and disable body output
 843                 wfDebug( __METHOD__ . ": NOT MODIFIED, $info", 'private' );
 844                 ini_set( 'zlib.output_compression', 0 );
 845                 $this->getRequest()->response()->statusHeader( 304 );
 846                 $this->sendCacheControl();
 847                 $this->disable();
 848
 849                 // Don't output a compressed blob when using ob_gzhandler;
 850                 // it's technically against HTTP spec and seems to confuse
 851                 // Firefox when the response gets split over two packets.
 852                 wfClearOutputBuffers();
 853
 854                 return true;
 855         }
 856
 857         /**
 858          * @param int $reqTime Time of request (eg. now)
 859          * @param int $maxAge Cache TTL in seconds
 860          * @return int Timestamp
 861          */
 862         private function getCdnCacheEpoch( $reqTime, $maxAge ) {
 863                 // Ensure Last-Modified is never more than (wgSquidMaxage) in the past,
 864                 // because even if the wiki page content hasn't changed since, static
 865                 // resources may have changed (skin HTML, interface messages, urls, etc.)
 866                 // and must roll-over in a timely manner (T46570)
 867                 return $reqTime - $maxAge;
 868         }
 869
 870         /**
 871          * Override the last modified timestamp
 872          *
 873          * @param string $timestamp New timestamp, in a format readable by
 874          *        wfTimestamp()
 875          */
 876         public function setLastModified( $timestamp ) {
 877                 $this->mLastModified = wfTimestamp( TS_RFC2822, $timestamp );
 878         }
 879
 880         /**
 881          * Set the robot policy for the page: <http://www.robotstxt.org/meta.html>
 882          *
 883          * @param string $policy The literal string to output as the contents of
 884          *   the meta tag.  Will be parsed according to the spec and output in
 885          *   standardized form.
 886          * @return null
 887          */
 888         public function setRobotPolicy( $policy ) {
 889                 $policy = Article::formatRobotPolicy( $policy );
 890
 891                 if ( isset( $policy['index'] ) ) {
 892                         $this->setIndexPolicy( $policy['index'] );
 893                 }
 894                 if ( isset( $policy['follow'] ) ) {
 895                         $this->setFollowPolicy( $policy['follow'] );
 896                 }
 897         }
 898
 899         /**
 900          * Set the index policy for the page, but leave the follow policy un-
 901          * touched.
 902          *
 903          * @param string $policy Either 'index' or 'noindex'.
 904          * @return null
 905          */
 906         public function setIndexPolicy( $policy ) {
 907                 $policy = trim( $policy );
 908                 if ( in_array( $policy, [ 'index', 'noindex' ] ) ) {
 909                         $this->mIndexPolicy = $policy;
 910                 }
 911         }
 912
 913         /**
 914          * Set the follow policy for the page, but leave the index policy un-
 915          * touched.
 916          *
 917          * @param string $policy Either 'follow' or 'nofollow'.
 918          * @return null
 919          */
 920         public function setFollowPolicy( $policy ) {
 921                 $policy = trim( $policy );
 922                 if ( in_array( $policy, [ 'follow', 'nofollow' ] ) ) {
 923                         $this->mFollowPolicy = $policy;
 924                 }
 925         }
 926
 927         /**
 928          * Set the new value of the "action text", this will be added to the
 929          * "HTML title", separated from it with " - ".
 930          *
 931          * @param string $text New value of the "action text"
 932          */
 933         public function setPageTitleActionText( $text ) {
 934                 $this->mPageTitleActionText = $text;
 935         }
 936
 937         /**
 938          * Get the value of the "action text"
 939          *
 940          * @return string
 941          */
 942         public function getPageTitleActionText() {
 943                 return $this->mPageTitleActionText;
 944         }
 945
 946         /**
 947          * "HTML title" means the contents of "<title>".
 948          * It is stored as plain, unescaped text and will be run through htmlspecialchars in the skin file.
 949          *
 950          * @param string|Message $name
 951          */
 952         public function setHTMLTitle( $name ) {
 953                 if ( $name instanceof Message ) {
 954                         $this->mHTMLtitle = $name->setContext( $this->getContext() )->text();
 955                 } else {
 956                         $this->mHTMLtitle = $name;
 957                 }
 958         }
 959
 960         /**
 961          * Return the "HTML title", i.e. the content of the "<title>" tag.
 962          *
 963          * @return string
 964          */
 965         public function getHTMLTitle() {
 966                 return $this->mHTMLtitle;
 967         }
 968
 969         /**
 970          * Set $mRedirectedFrom, the Title of the page which redirected us to the current page.
 971          *
 972          * @param Title $t
 973          */
 974         public function setRedirectedFrom( $t ) {
 975                 $this->mRedirectedFrom = $t;
 976         }
 977
 978         /**
 979          * "Page title" means the contents of \<h1\>. It is stored as a valid HTML
 980          * fragment. This function allows good tags like \<sup\> in the \<h1\> tag,
 981          * but not bad tags like \<script\>. This function automatically sets
 982          * \<title\> to the same content as \<h1\> but with all tags removed. Bad
 983          * tags that were escaped in \<h1\> will still be escaped in \<title\>, and
 984          * good tags like \<i\> will be dropped entirely.
 985          *
 986          * @param string|Message $name
 987          */
 988         public function setPageTitle( $name ) {
 989                 if ( $name instanceof Message ) {
 990                         $name = $name->setContext( $this->getContext() )->text();
 991                 }
 992
 993                 # change "<script>foo&bar</script>" to "&lt;script&gt;foo&amp;bar&lt;/script&gt;"
 994                 # but leave "<i>foobar</i>" alone
 995                 $nameWithTags = Sanitizer::normalizeCharReferences( Sanitizer::removeHTMLtags( $name ) );
 996                 $this->mPagetitle = $nameWithTags;
 997
 998                 # change "<i>foo&amp;bar</i>" to "foo&bar"
 999                 $this->setHTMLTitle(
1000                         $this->msg( 'pagetitle' )->rawParams( Sanitizer::stripAllTags( $nameWithTags ) )
1001                                 ->inContentLanguage()
1002                 );
1003         }
1004
1005         /**
1006          * Return the "page title", i.e. the content of the \<h1\> tag.
1007          *
1008          * @return string
1009          */
1010         public function getPageTitle() {
1011                 return $this->mPagetitle;
1012         }
1013
1014         /**
1015          * Set the Title object to use
1016          *
1017          * @param Title $t
1018          */
1019         public function setTitle( Title $t ) {
1020                 $this->getContext()->setTitle( $t );
1021         }
1022
1023         /**
1024          * Replace the subtitle with $str
1025          *
1026          * @param string|Message $str New value of the subtitle. String should be safe HTML.
1027          */
1028         public function setSubtitle( $str ) {
1029                 $this->clearSubtitle();
1030                 $this->addSubtitle( $str );
1031         }
1032
1033         /**
1034          * Add $str to the subtitle
1035          *
1036          * @param string|Message $str String or Message to add to the subtitle. String should be safe HTML.
1037          */
1038         public function addSubtitle( $str ) {
1039                 if ( $str instanceof Message ) {
1040                         $this->mSubtitle[] = $str->setContext( $this->getContext() )->parse();
1041                 } else {
1042                         $this->mSubtitle[] = $str;
1043                 }
1044         }
1045
1046         /**
1047          * Build message object for a subtitle containing a backlink to a page
1048          *
1049          * @param Title $title Title to link to
1050          * @param array $query Array of additional parameters to include in the link
1051          * @return Message
1052          * @since 1.25
1053          */
1054         public static function buildBacklinkSubtitle( Title $title, $query = [] ) {
1055                 if ( $title->isRedirect() ) {
1056                         $query['redirect'] = 'no';
1057                 }
1058                 $linkRenderer = MediaWikiServices::getInstance()->getLinkRenderer();
1059                 return wfMessage( 'backlinksubtitle' )
1060                         ->rawParams( $linkRenderer->makeLink( $title, null, [], $query ) );
1061         }
1062
1063         /**
1064          * Add a subtitle containing a backlink to a page
1065          *
1066          * @param Title $title Title to link to
1067          * @param array $query Array of additional parameters to include in the link
1068          */
1069         public function addBacklinkSubtitle( Title $title, $query = [] ) {
1070                 $this->addSubtitle( self::buildBacklinkSubtitle( $title, $query ) );
1071         }
1072
1073         /**
1074          * Clear the subtitles
1075          */
1076         public function clearSubtitle() {
1077                 $this->mSubtitle = [];
1078         }
1079
1080         /**
1081          * Get the subtitle
1082          *
1083          * @return string
1084          */
1085         public function getSubtitle() {
1086                 return implode( "<br />\n\t\t\t\t", $this->mSubtitle );
1087         }
1088
1089         /**
1090          * Set the page as printable, i.e. it'll be displayed with all
1091          * print styles included
1092          */
1093         public function setPrintable() {
1094                 $this->mPrintable = true;
1095         }
1096
1097         /**
1098          * Return whether the page is "printable"
1099          *
1100          * @return bool
1101          */
1102         public function isPrintable() {
1103                 return $this->mPrintable;
1104         }
1105
1106         /**
1107          * Disable output completely, i.e. calling output() will have no effect
1108          */
1109         public function disable() {
1110                 $this->mDoNothing = true;
1111         }
1112
1113         /**
1114          * Return whether the output will be completely disabled
1115          *
1116          * @return bool
1117          */
1118         public function isDisabled() {
1119                 return $this->mDoNothing;
1120         }
1121
1122         /**
1123          * Show an "add new section" link?
1124          *
1125          * @return bool
1126          */
1127         public function showNewSectionLink() {
1128                 return $this->mNewSectionLink;
1129         }
1130
1131         /**
1132          * Forcibly hide the new section link?
1133          *
1134          * @return bool
1135          */
1136         public function forceHideNewSectionLink() {
1137                 return $this->mHideNewSectionLink;
1138         }
1139
1140         /**
1141          * Add or remove feed links in the page header
1142          * This is mainly kept for backward compatibility, see OutputPage::addFeedLink()
1143          * for the new version
1144          * @see addFeedLink()
1145          *
1146          * @param bool $show True: add default feeds, false: remove all feeds
1147          */
1148         public function setSyndicated( $show = true ) {
1149                 if ( $show ) {
1150                         $this->setFeedAppendQuery( false );
1151                 } else {
1152                         $this->mFeedLinks = [];
1153                 }
1154         }
1155
1156         /**
1157          * Add default feeds to the page header
1158          * This is mainly kept for backward compatibility, see OutputPage::addFeedLink()
1159          * for the new version
1160          * @see addFeedLink()
1161          *
1162          * @param string $val Query to append to feed links or false to output
1163          *        default links
1164          */
1165         public function setFeedAppendQuery( $val ) {
1166                 $this->mFeedLinks = [];
1167
1168                 foreach ( $this->getConfig()->get( 'AdvertisedFeedTypes' ) as $type ) {
1169                         $query = "feed=$type";
1170                         if ( is_string( $val ) ) {
1171                                 $query .= '&' . $val;
1172                         }
1173                         $this->mFeedLinks[$type] = $this->getTitle()->getLocalURL( $query );
1174                 }
1175         }
1176
1177         /**
1178          * Add a feed link to the page header
1179          *
1180          * @param string $format Feed type, should be a key of $wgFeedClasses
1181          * @param string $href URL
1182          */
1183         public function addFeedLink( $format, $href ) {
1184                 if ( in_array( $format, $this->getConfig()->get( 'AdvertisedFeedTypes' ) ) ) {
1185                         $this->mFeedLinks[$format] = $href;
1186                 }
1187         }
1188
1189         /**
1190          * Should we output feed links for this page?
1191          * @return bool
1192          */
1193         public function isSyndicated() {
1194                 return count( $this->mFeedLinks ) > 0;
1195         }
1196
1197         /**
1198          * Return URLs for each supported syndication format for this page.
1199          * @return array Associating format keys with URLs
1200          */
1201         public function getSyndicationLinks() {
1202                 return $this->mFeedLinks;
1203         }
1204
1205         /**
1206          * Will currently always return null
1207          *
1208          * @return null
1209          */
1210         public function getFeedAppendQuery() {
1211                 return $this->mFeedLinksAppendQuery;
1212         }
1213
1214         /**
1215          * Set whether the displayed content is related to the source of the
1216          * corresponding article on the wiki
1217          * Setting true will cause the change "article related" toggle to true
1218          *
1219          * @param bool $v
1220          */
1221         public function setArticleFlag( $v ) {
1222                 $this->mIsarticle = $v;
1223                 if ( $v ) {
1224                         $this->mIsArticleRelated = $v;
1225                 }
1226         }
1227
1228         /**
1229          * Return whether the content displayed page is related to the source of
1230          * the corresponding article on the wiki
1231          *
1232          * @return bool
1233          */
1234         public function isArticle() {
1235                 return $this->mIsarticle;
1236         }
1237
1238         /**
1239          * Set whether this page is related an article on the wiki
1240          * Setting false will cause the change of "article flag" toggle to false
1241          *
1242          * @param bool $v
1243          */
1244         public function setArticleRelated( $v ) {
1245                 $this->mIsArticleRelated = $v;
1246                 if ( !$v ) {
1247                         $this->mIsarticle = false;
1248                 }
1249         }
1250
1251         /**
1252          * Return whether this page is related an article on the wiki
1253          *
1254          * @return bool
1255          */
1256         public function isArticleRelated() {
1257                 return $this->mIsArticleRelated;
1258         }
1259
1260         /**
1261          * Add new language links
1262          *
1263          * @param string[] $newLinkArray Array of interwiki-prefixed (non DB key) titles
1264          *                               (e.g. 'fr:Test page')
1265          */
1266         public function addLanguageLinks( array $newLinkArray ) {
1267                 $this->mLanguageLinks += $newLinkArray;
1268         }
1269
1270         /**
1271          * Reset the language links and add new language links
1272          *
1273          * @param string[] $newLinkArray Array of interwiki-prefixed (non DB key) titles
1274          *                               (e.g. 'fr:Test page')
1275          */
1276         public function setLanguageLinks( array $newLinkArray ) {
1277                 $this->mLanguageLinks = $newLinkArray;
1278         }
1279
1280         /**
1281          * Get the list of language links
1282          *
1283          * @return string[] Array of interwiki-prefixed (non DB key) titles (e.g. 'fr:Test page')
1284          */
1285         public function getLanguageLinks() {
1286                 return $this->mLanguageLinks;
1287         }
1288
1289         /**
1290          * Add an array of categories, with names in the keys
1291          *
1292          * @param array $categories Mapping category name => sort key
1293          */
1294         public function addCategoryLinks( array $categories ) {
1295                 global $wgContLang;
1296
1297                 if ( !is_array( $categories ) || count( $categories ) == 0 ) {
1298                         return;
1299                 }
1300
1301                 $res = $this->addCategoryLinksToLBAndGetResult( $categories );
1302
1303                 # Set all the values to 'normal'.
1304                 $categories = array_fill_keys( array_keys( $categories ), 'normal' );
1305
1306                 # Mark hidden categories
1307                 foreach ( $res as $row ) {
1308                         if ( isset( $row->pp_value ) ) {
1309                                 $categories[$row->page_title] = 'hidden';
1310                         }
1311                 }
1312
1313                 // Avoid PHP 7.1 warning of passing $this by reference
1314                 $outputPage = $this;
1315                 # Add the remaining categories to the skin
1316                 if ( Hooks::run(
1317                         'OutputPageMakeCategoryLinks',
1318                         [ &$outputPage, $categories, &$this->mCategoryLinks ] )
1319                 ) {
1320                         $linkRenderer = MediaWikiServices::getInstance()->getLinkRenderer();
1321                         foreach ( $categories as $category => $type ) {
1322                                 // array keys will cast numeric category names to ints, so cast back to string
1323                                 $category = (string)$category;
1324                                 $origcategory = $category;
1325                                 $title = Title::makeTitleSafe( NS_CATEGORY, $category );
1326                                 if ( !$title ) {
1327                                         continue;
1328                                 }
1329                                 $wgContLang->findVariantLink( $category, $title, true );
1330                                 if ( $category != $origcategory && array_key_exists( $category, $categories ) ) {
1331                                         continue;
1332                                 }
1333                                 $text = $wgContLang->convertHtml( $title->getText() );
1334                                 $this->mCategories[$type][] = $title->getText();
1335                                 $this->mCategoryLinks[$type][] = $linkRenderer->makeLink( $title, new HtmlArmor( $text ) );
1336                         }
1337                 }
1338         }
1339
1340         /**
1341          * @param array $categories
1342          * @return bool|ResultWrapper
1343          */
1344         protected function addCategoryLinksToLBAndGetResult( array $categories ) {
1345                 # Add the links to a LinkBatch
1346                 $arr = [ NS_CATEGORY => $categories ];
1347                 $lb = new LinkBatch;
1348                 $lb->setArray( $arr );
1349
1350                 # Fetch existence plus the hiddencat property
1351                 $dbr = wfGetDB( DB_REPLICA );
1352                 $fields = array_merge(
1353                         LinkCache::getSelectFields(),
1354                         [ 'page_namespace', 'page_title', 'pp_value' ]
1355                 );
1356
1357                 $res = $dbr->select( [ 'page', 'page_props' ],
1358                         $fields,
1359                         $lb->constructSet( 'page', $dbr ),
1360                         __METHOD__,
1361                         [],
1362                         [ 'page_props' => [ 'LEFT JOIN', [
1363                                 'pp_propname' => 'hiddencat',
1364                                 'pp_page = page_id'
1365                         ] ] ]
1366                 );
1367
1368                 # Add the results to the link cache
1369                 $lb->addResultToCache( LinkCache::singleton(), $res );
1370
1371                 return $res;
1372         }
1373
1374         /**
1375          * Reset the category links (but not the category list) and add $categories
1376          *
1377          * @param array $categories Mapping category name => sort key
1378          */
1379         public function setCategoryLinks( array $categories ) {
1380                 $this->mCategoryLinks = [];
1381                 $this->addCategoryLinks( $categories );
1382         }
1383
1384         /**
1385          * Get the list of category links, in a 2-D array with the following format:
1386          * $arr[$type][] = $link, where $type is either "normal" or "hidden" (for
1387          * hidden categories) and $link a HTML fragment with a link to the category
1388          * page
1389          *
1390          * @return array
1391          */
1392         public function getCategoryLinks() {
1393                 return $this->mCategoryLinks;
1394         }
1395
1396         /**
1397          * Get the list of category names this page belongs to.
1398          *
1399          * @param string $type The type of categories which should be returned. Possible values:
1400          *  * all: all categories of all types
1401          *  * hidden: only the hidden categories
1402          *  * normal: all categories, except hidden categories
1403          * @return array Array of strings
1404          */
1405         public function getCategories( $type = 'all' ) {
1406                 if ( $type === 'all' ) {
1407                         $allCategories = [];
1408                         foreach ( $this->mCategories as $categories ) {
1409                                 $allCategories = array_merge( $allCategories, $categories );
1410                         }
1411                         return $allCategories;
1412                 }
1413                 if ( !isset( $this->mCategories[$type] ) ) {
1414                         throw new InvalidArgumentException( 'Invalid category type given: ' . $type );
1415                 }
1416                 return $this->mCategories[$type];
1417         }
1418
1419         /**
1420          * Add an array of indicators, with their identifiers as array
1421          * keys and HTML contents as values.
1422          *
1423          * In case of duplicate keys, existing values are overwritten.
1424          *
1425          * @param array $indicators
1426          * @since 1.25
1427          */
1428         public function setIndicators( array $indicators ) {
1429                 $this->mIndicators = $indicators + $this->mIndicators;
1430                 // Keep ordered by key
1431                 ksort( $this->mIndicators );
1432         }
1433
1434         /**
1435          * Get the indicators associated with this page.
1436          *
1437          * The array will be internally ordered by item keys.
1438          *
1439          * @return array Keys: identifiers, values: HTML contents
1440          * @since 1.25
1441          */
1442         public function getIndicators() {
1443                 return $this->mIndicators;
1444         }
1445
1446         /**
1447          * Adds help link with an icon via page indicators.
1448          * Link target can be overridden by a local message containing a wikilink:
1449          * the message key is: lowercase action or special page name + '-helppage'.
1450          * @param string $to Target MediaWiki.org page title or encoded URL.
1451          * @param bool $overrideBaseUrl Whether $url is a full URL, to avoid MW.o.
1452          * @since 1.25
1453          */
1454         public function addHelpLink( $to, $overrideBaseUrl = false ) {
1455                 $this->addModuleStyles( 'mediawiki.helplink' );
1456                 $text = $this->msg( 'helppage-top-gethelp' )->escaped();
1457
1458                 if ( $overrideBaseUrl ) {
1459                         $helpUrl = $to;
1460                 } else {
1461                         $toUrlencoded = wfUrlencode( str_replace( ' ', '_', $to ) );
1462                         $helpUrl = "//www.mediawiki.org/wiki/Special:MyLanguage/$toUrlencoded";
1463                 }
1464
1465                 $link = Html::rawElement(
1466                         'a',
1467                         [
1468                                 'href' => $helpUrl,
1469                                 'target' => '_blank',
1470                                 'class' => 'mw-helplink',
1471                         ],
1472                         $text
1473                 );
1474
1475                 $this->setIndicators( [ 'mw-helplink' => $link ] );
1476         }
1477
1478         /**
1479          * Do not allow scripts which can be modified by wiki users to load on this page;
1480          * only allow scripts bundled with, or generated by, the software.
1481          * Site-wide styles are controlled by a config setting, since they can be
1482          * used to create a custom skin/theme, but not user-specific ones.
1483          *
1484          * @todo this should be given a more accurate name
1485          */
1486         public function disallowUserJs() {
1487                 $this->reduceAllowedModules(
1488                         ResourceLoaderModule::TYPE_SCRIPTS,
1489                         ResourceLoaderModule::ORIGIN_CORE_INDIVIDUAL
1490                 );
1491
1492                 // Site-wide styles are controlled by a config setting, see T73621
1493                 // for background on why. User styles are never allowed.
1494                 if ( $this->getConfig()->get( 'AllowSiteCSSOnRestrictedPages' ) ) {
1495                         $styleOrigin = ResourceLoaderModule::ORIGIN_USER_SITEWIDE;
1496                 } else {
1497                         $styleOrigin = ResourceLoaderModule::ORIGIN_CORE_INDIVIDUAL;
1498                 }
1499                 $this->reduceAllowedModules(
1500                         ResourceLoaderModule::TYPE_STYLES,
1501                         $styleOrigin
1502                 );
1503         }
1504
1505         /**
1506          * Show what level of JavaScript / CSS untrustworthiness is allowed on this page
1507          * @see ResourceLoaderModule::$origin
1508          * @param string $type ResourceLoaderModule TYPE_ constant
1509          * @return int ResourceLoaderModule ORIGIN_ class constant
1510          */
1511         public function getAllowedModules( $type ) {
1512                 if ( $type == ResourceLoaderModule::TYPE_COMBINED ) {
1513                         return min( array_values( $this->mAllowedModules ) );
1514                 } else {
1515                         return isset( $this->mAllowedModules[$type] )
1516                                 ? $this->mAllowedModules[$type]
1517                                 : ResourceLoaderModule::ORIGIN_ALL;
1518                 }
1519         }
1520
1521         /**
1522          * Limit the highest level of CSS/JS untrustworthiness allowed.
1523          *
1524          * If passed the same or a higher level than the current level of untrustworthiness set, the
1525          * level will remain unchanged.
1526          *
1527          * @param string $type
1528          * @param int $level ResourceLoaderModule class constant
1529          */
1530         public function reduceAllowedModules( $type, $level ) {
1531                 $this->mAllowedModules[$type] = min( $this->getAllowedModules( $type ), $level );
1532         }
1533
1534         /**
1535          * Prepend $text to the body HTML
1536          *
1537          * @param string $text HTML
1538          */
1539         public function prependHTML( $text ) {
1540                 $this->mBodytext = $text . $this->mBodytext;
1541         }
1542
1543         /**
1544          * Append $text to the body HTML
1545          *
1546          * @param string $text HTML
1547          */
1548         public function addHTML( $text ) {
1549                 $this->mBodytext .= $text;
1550         }
1551
1552         /**
1553          * Shortcut for adding an Html::element via addHTML.
1554          *
1555          * @since 1.19
1556          *
1557          * @param string $element
1558          * @param array $attribs
1559          * @param string $contents
1560          */
1561         public function addElement( $element, array $attribs = [], $contents = '' ) {
1562                 $this->addHTML( Html::element( $element, $attribs, $contents ) );
1563         }
1564
1565         /**
1566          * Clear the body HTML
1567          */
1568         public function clearHTML() {
1569                 $this->mBodytext = '';
1570         }
1571
1572         /**
1573          * Get the body HTML
1574          *
1575          * @return string HTML
1576          */
1577         public function getHTML() {
1578                 return $this->mBodytext;
1579         }
1580
1581         /**
1582          * Get/set the ParserOptions object to use for wikitext parsing
1583          *
1584          * @param ParserOptions|null $options Either the ParserOption to use or null to only get the
1585          *   current ParserOption object. This parameter is deprecated since 1.31.
1586          * @return ParserOptions
1587          */
1588         public function parserOptions( $options = null ) {
1589                 if ( $options !== null ) {
1590                         wfDeprecated( __METHOD__ . ' with non-null $options', '1.31' );
1591                 }
1592
1593                 if ( $options !== null && !empty( $options->isBogus ) ) {
1594                         // Someone is trying to set a bogus pre-$wgUser PO. Check if it has
1595                         // been changed somehow, and keep it if so.
1596                         $anonPO = ParserOptions::newFromAnon();
1597                         $anonPO->setAllowUnsafeRawHtml( false );
1598                         if ( !$options->matches( $anonPO ) ) {
1599                                 wfLogWarning( __METHOD__ . ': Setting a changed bogus ParserOptions: ' . wfGetAllCallers( 5 ) );
1600                                 $options->isBogus = false;
1601                         }
1602                 }
1603
1604                 if ( !$this->mParserOptions ) {
1605                         if ( !$this->getContext()->getUser()->isSafeToLoad() ) {
1606                                 // $wgUser isn't unstubbable yet, so don't try to get a
1607                                 // ParserOptions for it. And don't cache this ParserOptions
1608                                 // either.
1609                                 $po = ParserOptions::newFromAnon();
1610                                 $po->setAllowUnsafeRawHtml( false );
1611                                 $po->isBogus = true;
1612                                 if ( $options !== null ) {
1613                                         $this->mParserOptions = empty( $options->isBogus ) ? $options : null;
1614                                 }
1615                                 return $po;
1616                         }
1617
1618                         $this->mParserOptions = ParserOptions::newFromContext( $this->getContext() );
1619                         $this->mParserOptions->setAllowUnsafeRawHtml( false );
1620                 }
1621
1622                 if ( $options !== null && !empty( $options->isBogus ) ) {
1623                         // They're trying to restore the bogus pre-$wgUser PO. Do the right
1624                         // thing.
1625                         return wfSetVar( $this->mParserOptions, null, true );
1626                 } else {
1627                         return wfSetVar( $this->mParserOptions, $options );
1628                 }
1629         }
1630
1631         /**
1632          * Set the revision ID which will be seen by the wiki text parser
1633          * for things such as embedded {{REVISIONID}} variable use.
1634          *
1635          * @param int|null $revid An positive integer, or null
1636          * @return mixed Previous value
1637          */
1638         public function setRevisionId( $revid ) {
1639                 $val = is_null( $revid ) ? null : intval( $revid );
1640                 return wfSetVar( $this->mRevisionId, $val );
1641         }
1642
1643         /**
1644          * Get the displayed revision ID
1645          *
1646          * @return int
1647          */
1648         public function getRevisionId() {
1649                 return $this->mRevisionId;
1650         }
1651
1652         /**
1653          * Set the timestamp of the revision which will be displayed. This is used
1654          * to avoid a extra DB call in Skin::lastModified().
1655          *
1656          * @param string|null $timestamp
1657          * @return mixed Previous value
1658          */
1659         public function setRevisionTimestamp( $timestamp ) {
1660                 return wfSetVar( $this->mRevisionTimestamp, $timestamp );
1661         }
1662
1663         /**
1664          * Get the timestamp of displayed revision.
1665          * This will be null if not filled by setRevisionTimestamp().
1666          *
1667          * @return string|null
1668          */
1669         public function getRevisionTimestamp() {
1670                 return $this->mRevisionTimestamp;
1671         }
1672
1673         /**
1674          * Set the displayed file version
1675          *
1676          * @param File|bool $file
1677          * @return mixed Previous value
1678          */
1679         public function setFileVersion( $file ) {
1680                 $val = null;
1681                 if ( $file instanceof File && $file->exists() ) {
1682                         $val = [ 'time' => $file->getTimestamp(), 'sha1' => $file->getSha1() ];
1683                 }
1684                 return wfSetVar( $this->mFileVersion, $val, true );
1685         }
1686
1687         /**
1688          * Get the displayed file version
1689          *
1690          * @return array|null ('time' => MW timestamp, 'sha1' => sha1)
1691          */
1692         public function getFileVersion() {
1693                 return $this->mFileVersion;
1694         }
1695
1696         /**
1697          * Get the templates used on this page
1698          *
1699          * @return array (namespace => dbKey => revId)
1700          * @since 1.18
1701          */
1702         public function getTemplateIds() {
1703                 return $this->mTemplateIds;
1704         }
1705
1706         /**
1707          * Get the files used on this page
1708          *
1709          * @return array (dbKey => array('time' => MW timestamp or null, 'sha1' => sha1 or ''))
1710          * @since 1.18
1711          */
1712         public function getFileSearchOptions() {
1713                 return $this->mImageTimeKeys;
1714         }
1715
1716         /**
1717          * Convert wikitext to HTML and add it to the buffer
1718          * Default assumes that the current page title will be used.
1719          *
1720          * @param string $text
1721          * @param bool $linestart Is this the start of a line?
1722          * @param bool $interface Is this text in the user interface language?
1723          * @throws MWException
1724          */
1725         public function addWikiText( $text, $linestart = true, $interface = true ) {
1726                 $title = $this->getTitle(); // Work around E_STRICT
1727                 if ( !$title ) {
1728                         throw new MWException( 'Title is null' );
1729                 }
1730                 $this->addWikiTextTitle( $text, $title, $linestart, /*tidy*/false, $interface );
1731         }
1732
1733         /**
1734          * Add wikitext with a custom Title object
1735          *
1736          * @param string $text Wikitext
1737          * @param Title &$title
1738          * @param bool $linestart Is this the start of a line?
1739          */
1740         public function addWikiTextWithTitle( $text, &$title, $linestart = true ) {
1741                 $this->addWikiTextTitle( $text, $title, $linestart );
1742         }
1743
1744         /**
1745          * Add wikitext with a custom Title object and tidy enabled.
1746          *
1747          * @param string $text Wikitext
1748          * @param Title &$title
1749          * @param bool $linestart Is this the start of a line?
1750          */
1751         function addWikiTextTitleTidy( $text, &$title, $linestart = true ) {
1752                 $this->addWikiTextTitle( $text, $title, $linestart, true );
1753         }
1754
1755         /**
1756          * Add wikitext with tidy enabled
1757          *
1758          * @param string $text Wikitext
1759          * @param bool $linestart Is this the start of a line?
1760          */
1761         public function addWikiTextTidy( $text, $linestart = true ) {
1762                 $title = $this->getTitle();
1763                 $this->addWikiTextTitleTidy( $text, $title, $linestart );
1764         }
1765
1766         /**
1767          * Add wikitext with a custom Title object
1768          *
1769          * @param string $text Wikitext
1770          * @param Title $title
1771          * @param bool $linestart Is this the start of a line?
1772          * @param bool $tidy Whether to use tidy
1773          * @param bool $interface Whether it is an interface message
1774          *   (for example disables conversion)
1775          */
1776         public function addWikiTextTitle( $text, Title $title, $linestart,
1777                 $tidy = false, $interface = false
1778         ) {
1779                 global $wgParser;
1780
1781                 $popts = $this->parserOptions();
1782                 $oldTidy = $popts->setTidy( $tidy );
1783                 $popts->setInterfaceMessage( (bool)$interface );
1784
1785                 $parserOutput = $wgParser->getFreshParser()->parse(
1786                         $text, $title, $popts,
1787                         $linestart, true, $this->mRevisionId
1788                 );
1789
1790                 $popts->setTidy( $oldTidy );
1791
1792                 $this->addParserOutput( $parserOutput, [
1793                         'enableSectionEditLinks' => false,
1794                 ] );
1795         }
1796
1797         /**
1798          * Add all metadata associated with a ParserOutput object, but without the actual HTML. This
1799          * includes categories, language links, ResourceLoader modules, effects of certain magic words,
1800          * and so on.
1801          *
1802          * @since 1.24
1803          * @param ParserOutput $parserOutput
1804          */
1805         public function addParserOutputMetadata( $parserOutput ) {
1806                 $this->mLanguageLinks += $parserOutput->getLanguageLinks();
1807                 $this->addCategoryLinks( $parserOutput->getCategories() );
1808                 $this->setIndicators( $parserOutput->getIndicators() );
1809                 $this->mNewSectionLink = $parserOutput->getNewSection();
1810                 $this->mHideNewSectionLink = $parserOutput->getHideNewSection();
1811
1812                 if ( !$parserOutput->isCacheable() ) {
1813                         $this->enableClientCache( false );
1814                 }
1815                 $this->mNoGallery = $parserOutput->getNoGallery();
1816                 $this->mHeadItems = array_merge( $this->mHeadItems, $parserOutput->getHeadItems() );
1817                 $this->addModules( $parserOutput->getModules() );
1818                 $this->addModuleScripts( $parserOutput->getModuleScripts() );
1819                 $this->addModuleStyles( $parserOutput->getModuleStyles() );
1820                 $this->addJsConfigVars( $parserOutput->getJsConfigVars() );
1821                 $this->mPreventClickjacking = $this->mPreventClickjacking
1822                         || $parserOutput->preventClickjacking();
1823
1824                 // Template versioning...
1825                 foreach ( (array)$parserOutput->getTemplateIds() as $ns => $dbks ) {
1826                         if ( isset( $this->mTemplateIds[$ns] ) ) {
1827                                 $this->mTemplateIds[$ns] = $dbks + $this->mTemplateIds[$ns];
1828                         } else {
1829                                 $this->mTemplateIds[$ns] = $dbks;
1830                         }
1831                 }
1832                 // File versioning...
1833                 foreach ( (array)$parserOutput->getFileSearchOptions() as $dbk => $data ) {
1834                         $this->mImageTimeKeys[$dbk] = $data;
1835                 }
1836
1837                 // Hooks registered in the object
1838                 $parserOutputHooks = $this->getConfig()->get( 'ParserOutputHooks' );
1839                 foreach ( $parserOutput->getOutputHooks() as $hookInfo ) {
1840                         list( $hookName, $data ) = $hookInfo;
1841                         if ( isset( $parserOutputHooks[$hookName] ) ) {
1842                                 call_user_func( $parserOutputHooks[$hookName], $this, $parserOutput, $data );
1843                         }
1844                 }
1845
1846                 // Enable OOUI if requested via ParserOutput
1847                 if ( $parserOutput->getEnableOOUI() ) {
1848                         $this->enableOOUI();
1849                 }
1850
1851                 // Include parser limit report
1852                 if ( !$this->limitReportJSData ) {
1853                         $this->limitReportJSData = $parserOutput->getLimitReportJSData();
1854                 }
1855
1856                 // Link flags are ignored for now, but may in the future be
1857                 // used to mark individual language links.
1858                 $linkFlags = [];
1859                 // Avoid PHP 7.1 warning of passing $this by reference
1860                 $outputPage = $this;
1861                 Hooks::run( 'LanguageLinks', [ $this->getTitle(), &$this->mLanguageLinks, &$linkFlags ] );
1862                 Hooks::runWithoutAbort( 'OutputPageParserOutput', [ &$outputPage, $parserOutput ] );
1863
1864                 // This check must be after 'OutputPageParserOutput' runs in addParserOutputMetadata
1865                 // so that extensions may modify ParserOutput to toggle TOC.
1866                 // This cannot be moved to addParserOutputText because that is not
1867                 // called by EditPage for Preview.
1868                 if ( $parserOutput->getTOCHTML() ) {
1869                         $this->mEnableTOC = true;
1870                 }
1871         }
1872
1873         /**
1874          * Add the HTML and enhancements for it (like ResourceLoader modules) associated with a
1875          * ParserOutput object, without any other metadata.
1876          *
1877          * @since 1.24
1878          * @param ParserOutput $parserOutput
1879          * @param array $poOptions Options to ParserOutput::getText()
1880          */
1881         public function addParserOutputContent( $parserOutput, $poOptions = [] ) {
1882                 $this->addParserOutputText( $parserOutput, $poOptions );
1883
1884                 $this->addModules( $parserOutput->getModules() );
1885                 $this->addModuleScripts( $parserOutput->getModuleScripts() );
1886                 $this->addModuleStyles( $parserOutput->getModuleStyles() );
1887
1888                 $this->addJsConfigVars( $parserOutput->getJsConfigVars() );
1889         }
1890
1891         /**
1892          * Add the HTML associated with a ParserOutput object, without any metadata.
1893          *
1894          * @since 1.24
1895          * @param ParserOutput $parserOutput
1896          * @param array $poOptions Options to ParserOutput::getText()
1897          */
1898         public function addParserOutputText( $parserOutput, $poOptions = [] ) {
1899                 $text = $parserOutput->getText( $poOptions );
1900                 // Avoid PHP 7.1 warning of passing $this by reference
1901                 $outputPage = $this;
1902                 Hooks::runWithoutAbort( 'OutputPageBeforeHTML', [ &$outputPage, &$text ] );
1903                 $this->addHTML( $text );
1904         }
1905
1906         /**
1907          * Add everything from a ParserOutput object.
1908          *
1909          * @param ParserOutput $parserOutput
1910          * @param array $poOptions Options to ParserOutput::getText()
1911          */
1912         function addParserOutput( $parserOutput, $poOptions = [] ) {
1913                 $this->addParserOutputMetadata( $parserOutput );
1914                 $this->addParserOutputText( $parserOutput, $poOptions );
1915         }
1916
1917         /**
1918          * Add the output of a QuickTemplate to the output buffer
1919          *
1920          * @param QuickTemplate &$template
1921          */
1922         public function addTemplate( &$template ) {
1923                 $this->addHTML( $template->getHTML() );
1924         }
1925
1926         /**
1927          * Parse wikitext and return the HTML.
1928          *
1929          * @param string $text
1930          * @param bool $linestart Is this the start of a line?
1931          * @param bool $interface Use interface language ($wgLang instead of
1932          *   $wgContLang) while parsing language sensitive magic words like GRAMMAR and PLURAL.
1933          *   This also disables LanguageConverter.
1934          * @param Language $language Target language object, will override $interface
1935          * @throws MWException
1936          * @return string HTML
1937          */
1938         public function parse( $text, $linestart = true, $interface = false, $language = null ) {
1939                 global $wgParser;
1940
1941                 if ( is_null( $this->getTitle() ) ) {
1942                         throw new MWException( 'Empty $mTitle in ' . __METHOD__ );
1943                 }
1944
1945                 $popts = $this->parserOptions();
1946                 if ( $interface ) {
1947                         $popts->setInterfaceMessage( true );
1948                 }
1949                 if ( $language !== null ) {
1950                         $oldLang = $popts->setTargetLanguage( $language );
1951                 }
1952
1953                 $parserOutput = $wgParser->getFreshParser()->parse(
1954                         $text, $this->getTitle(), $popts,
1955                         $linestart, true, $this->mRevisionId
1956                 );
1957
1958                 if ( $interface ) {
1959                         $popts->setInterfaceMessage( false );
1960                 }
1961                 if ( $language !== null ) {
1962                         $popts->setTargetLanguage( $oldLang );
1963                 }
1964
1965                 return $parserOutput->getText( [
1966                         'enableSectionEditLinks' => false,
1967                 ] );
1968         }
1969
1970         /**
1971          * Parse wikitext, strip paragraphs, and return the HTML.
1972          *
1973          * @param string $text
1974          * @param bool $linestart Is this the start of a line?
1975          * @param bool $interface Use interface language ($wgLang instead of
1976          *   $wgContLang) while parsing language sensitive magic
1977          *   words like GRAMMAR and PLURAL
1978          * @return string HTML
1979          */
1980         public function parseInline( $text, $linestart = true, $interface = false ) {
1981                 $parsed = $this->parse( $text, $linestart, $interface );
1982                 return Parser::stripOuterParagraph( $parsed );
1983         }
1984
1985         /**
1986          * Set the value of the "s-maxage" part of the "Cache-control" HTTP header
1987          *
1988          * @param int $maxage Maximum cache time on the CDN, in seconds.
1989          */
1990         public function setCdnMaxage( $maxage ) {
1991                 $this->mCdnMaxage = min( $maxage, $this->mCdnMaxageLimit );
1992         }
1993
1994         /**
1995          * Lower the value of the "s-maxage" part of the "Cache-control" HTTP header
1996          *
1997          * @param int $maxage Maximum cache time on the CDN, in seconds
1998          * @since 1.27
1999          */
2000         public function lowerCdnMaxage( $maxage ) {
2001                 $this->mCdnMaxageLimit = min( $maxage, $this->mCdnMaxageLimit );
2002                 $this->setCdnMaxage( $this->mCdnMaxage );
2003         }
2004
2005         /**
2006          * Get TTL in [$minTTL,$maxTTL] in pass it to lowerCdnMaxage()
2007          *
2008          * This sets and returns $minTTL if $mtime is false or null. Otherwise,
2009          * the TTL is higher the older the $mtime timestamp is. Essentially, the
2010          * TTL is 90% of the age of the object, subject to the min and max.
2011          *
2012          * @param string|int|float|bool|null $mtime Last-Modified timestamp
2013          * @param int $minTTL Mimimum TTL in seconds [default: 1 minute]
2014          * @param int $maxTTL Maximum TTL in seconds [default: $wgSquidMaxage]
2015          * @return int TTL in seconds
2016          * @since 1.28
2017          */
2018         public function adaptCdnTTL( $mtime, $minTTL = 0, $maxTTL = 0 ) {
2019                 $minTTL = $minTTL ?: IExpiringStore::TTL_MINUTE;
2020                 $maxTTL = $maxTTL ?: $this->getConfig()->get( 'SquidMaxage' );
2021
2022                 if ( $mtime === null || $mtime === false ) {
2023                         return $minTTL; // entity does not exist
2024                 }
2025
2026                 $age = time() - wfTimestamp( TS_UNIX, $mtime );
2027                 $adaptiveTTL = max( 0.9 * $age, $minTTL );
2028                 $adaptiveTTL = min( $adaptiveTTL, $maxTTL );
2029
2030                 $this->lowerCdnMaxage( (int)$adaptiveTTL );
2031
2032                 return $adaptiveTTL;
2033         }
2034
2035         /**
2036          * Use enableClientCache(false) to force it to send nocache headers
2037          *
2038          * @param bool $state
2039          *
2040          * @return bool
2041          */
2042         public function enableClientCache( $state ) {
2043                 return wfSetVar( $this->mEnableClientCache, $state );
2044         }
2045
2046         /**
2047          * Get the list of cookies that will influence on the cache
2048          *
2049          * @return array
2050          */
2051         function getCacheVaryCookies() {
2052                 static $cookies;
2053                 if ( $cookies === null ) {
2054                         $config = $this->getConfig();
2055                         $cookies = array_merge(
2056                                 SessionManager::singleton()->getVaryCookies(),
2057                                 [
2058                                         'forceHTTPS',
2059                                 ],
2060                                 $config->get( 'CacheVaryCookies' )
2061                         );
2062                         Hooks::run( 'GetCacheVaryCookies', [ $this, &$cookies ] );
2063                 }
2064                 return $cookies;
2065         }
2066
2067         /**
2068          * Check if the request has a cache-varying cookie header
2069          * If it does, it's very important that we don't allow public caching
2070          *
2071          * @return bool
2072          */
2073         function haveCacheVaryCookies() {
2074                 $request = $this->getRequest();
2075                 foreach ( $this->getCacheVaryCookies() as $cookieName ) {
2076                         if ( $request->getCookie( $cookieName, '', '' ) !== '' ) {
2077                                 wfDebug( __METHOD__ . ": found $cookieName\n" );
2078                                 return true;
2079                         }
2080                 }
2081                 wfDebug( __METHOD__ . ": no cache-varying cookies found\n" );
2082                 return false;
2083         }
2084
2085         /**
2086          * Add an HTTP header that will influence on the cache
2087          *
2088          * @param string $header Header name
2089          * @param string[]|null $option Options for the Key header. See
2090          * https://datatracker.ietf.org/doc/draft-fielding-http-key/
2091          * for the list of valid options.
2092          */
2093         public function addVaryHeader( $header, array $option = null ) {
2094                 if ( !array_key_exists( $header, $this->mVaryHeader ) ) {
2095                         $this->mVaryHeader[$header] = [];
2096                 }
2097                 if ( !is_array( $option ) ) {
2098                         $option = [];
2099                 }
2100                 $this->mVaryHeader[$header] = array_unique( array_merge( $this->mVaryHeader[$header], $option ) );
2101         }
2102
2103         /**
2104          * Return a Vary: header on which to vary caches. Based on the keys of $mVaryHeader,
2105          * such as Accept-Encoding or Cookie
2106          *
2107          * @return string
2108          */
2109         public function getVaryHeader() {
2110                 // If we vary on cookies, let's make sure it's always included here too.
2111                 if ( $this->getCacheVaryCookies() ) {
2112                         $this->addVaryHeader( 'Cookie' );
2113                 }
2114
2115                 foreach ( SessionManager::singleton()->getVaryHeaders() as $header => $options ) {
2116                         $this->addVaryHeader( $header, $options );
2117                 }
2118                 return 'Vary: ' . implode( ', ', array_keys( $this->mVaryHeader ) );
2119         }
2120
2121         /**
2122          * Add an HTTP Link: header
2123          *
2124          * @param string $header Header value
2125          */
2126         public function addLinkHeader( $header ) {
2127                 $this->mLinkHeader[] = $header;
2128         }
2129
2130         /**
2131          * Return a Link: header. Based on the values of $mLinkHeader.
2132          *
2133          * @return string
2134          */
2135         public function getLinkHeader() {
2136                 if ( !$this->mLinkHeader ) {
2137                         return false;
2138                 }
2139
2140                 return 'Link: ' . implode( ',', $this->mLinkHeader );
2141         }
2142
2143         /**
2144          * Get a complete Key header
2145          *
2146          * @return string
2147          */
2148         public function getKeyHeader() {
2149                 $cvCookies = $this->getCacheVaryCookies();
2150
2151                 $cookiesOption = [];
2152                 foreach ( $cvCookies as $cookieName ) {
2153                         $cookiesOption[] = 'param=' . $cookieName;
2154                 }
2155                 $this->addVaryHeader( 'Cookie', $cookiesOption );
2156
2157                 foreach ( SessionManager::singleton()->getVaryHeaders() as $header => $options ) {
2158                         $this->addVaryHeader( $header, $options );
2159                 }
2160
2161                 $headers = [];
2162                 foreach ( $this->mVaryHeader as $header => $option ) {
2163                         $newheader = $header;
2164                         if ( is_array( $option ) && count( $option ) > 0 ) {
2165                                 $newheader .= ';' . implode( ';', $option );
2166                         }
2167                         $headers[] = $newheader;
2168                 }
2169                 $key = 'Key: ' . implode( ',', $headers );
2170
2171                 return $key;
2172         }
2173
2174         /**
2175          * T23672: Add Accept-Language to Vary and Key headers
2176          * if there's no 'variant' parameter existed in GET.
2177          *
2178          * For example:
2179          *   /w/index.php?title=Main_page should always be served; but
2180          *   /w/index.php?title=Main_page&variant=zh-cn should never be served.
2181          */
2182         function addAcceptLanguage() {
2183                 $title = $this->getTitle();
2184                 if ( !$title instanceof Title ) {
2185                         return;
2186                 }
2187
2188                 $lang = $title->getPageLanguage();
2189                 if ( !$this->getRequest()->getCheck( 'variant' ) && $lang->hasVariants() ) {
2190                         $variants = $lang->getVariants();
2191                         $aloption = [];
2192                         foreach ( $variants as $variant ) {
2193                                 if ( $variant === $lang->getCode() ) {
2194                                         continue;
2195                                 } else {
2196                                         $aloption[] = 'substr=' . $variant;
2197
2198                                         // IE and some other browsers use BCP 47 standards in
2199                                         // their Accept-Language header, like "zh-CN" or "zh-Hant".
2200                                         // We should handle these too.
2201                                         $variantBCP47 = LanguageCode::bcp47( $variant );
2202                                         if ( $variantBCP47 !== $variant ) {
2203                                                 $aloption[] = 'substr=' . $variantBCP47;
2204                                         }
2205                                 }
2206                         }
2207                         $this->addVaryHeader( 'Accept-Language', $aloption );
2208                 }
2209         }
2210
2211         /**
2212          * Set a flag which will cause an X-Frame-Options header appropriate for
2213          * edit pages to be sent. The header value is controlled by
2214          * $wgEditPageFrameOptions.
2215          *
2216          * This is the default for special pages. If you display a CSRF-protected
2217          * form on an ordinary view page, then you need to call this function.
2218          *
2219          * @param bool $enable
2220          */
2221         public function preventClickjacking( $enable = true ) {
2222                 $this->mPreventClickjacking = $enable;
2223         }
2224
2225         /**
2226          * Turn off frame-breaking. Alias for $this->preventClickjacking(false).
2227          * This can be called from pages which do not contain any CSRF-protected
2228          * HTML form.
2229          */
2230         public function allowClickjacking() {
2231                 $this->mPreventClickjacking = false;
2232         }
2233
2234         /**
2235          * Get the prevent-clickjacking flag
2236          *
2237          * @since 1.24
2238          * @return bool
2239          */
2240         public function getPreventClickjacking() {
2241                 return $this->mPreventClickjacking;
2242         }
2243
2244         /**
2245          * Get the X-Frame-Options header value (without the name part), or false
2246          * if there isn't one. This is used by Skin to determine whether to enable
2247          * JavaScript frame-breaking, for clients that don't support X-Frame-Options.
2248          *
2249          * @return string|false
2250          */
2251         public function getFrameOptions() {
2252                 $config = $this->getConfig();
2253                 if ( $config->get( 'BreakFrames' ) ) {
2254                         return 'DENY';
2255                 } elseif ( $this->mPreventClickjacking && $config->get( 'EditPageFrameOptions' ) ) {
2256                         return $config->get( 'EditPageFrameOptions' );
2257                 }
2258                 return false;
2259         }
2260
2261         /**
2262          * Send cache control HTTP headers
2263          */
2264         public function sendCacheControl() {
2265                 $response = $this->getRequest()->response();
2266                 $config = $this->getConfig();
2267
2268                 $this->addVaryHeader( 'Cookie' );
2269                 $this->addAcceptLanguage();
2270
2271                 # don't serve compressed data to clients who can't handle it
2272                 # maintain different caches for logged-in users and non-logged in ones
2273                 $response->header( $this->getVaryHeader() );
2274
2275                 if ( $config->get( 'UseKeyHeader' ) ) {
2276                         $response->header( $this->getKeyHeader() );
2277                 }
2278
2279                 if ( $this->mEnableClientCache ) {
2280                         if (
2281                                 $config->get( 'UseSquid' ) &&
2282                                 !$response->hasCookies() &&
2283                                 !SessionManager::getGlobalSession()->isPersistent() &&
2284                                 !$this->isPrintable() &&
2285                                 $this->mCdnMaxage != 0 &&
2286                                 !$this->haveCacheVaryCookies()
2287                         ) {
2288                                 if ( $config->get( 'UseESI' ) ) {
2289                                         # We'll purge the proxy cache explicitly, but require end user agents
2290                                         # to revalidate against the proxy on each visit.
2291                                         # Surrogate-Control controls our CDN, Cache-Control downstream caches
2292                                         wfDebug( __METHOD__ .
2293                                                 ": proxy caching with ESI; {$this->mLastModified} **", 'private' );
2294                                         # start with a shorter timeout for initial testing
2295                                         # header( 'Surrogate-Control: max-age=2678400+2678400, content="ESI/1.0"');
2296                                         $response->header(
2297                                                 "Surrogate-Control: max-age={$config->get( 'SquidMaxage' )}" .
2298                                                 "+{$this->mCdnMaxage}, content=\"ESI/1.0\""
2299                                         );
2300                                         $response->header( 'Cache-Control: s-maxage=0, must-revalidate, max-age=0' );
2301                                 } else {
2302                                         # We'll purge the proxy cache for anons explicitly, but require end user agents
2303                                         # to revalidate against the proxy on each visit.
2304                                         # IMPORTANT! The CDN needs to replace the Cache-Control header with
2305                                         # Cache-Control: s-maxage=0, must-revalidate, max-age=0
2306                                         wfDebug( __METHOD__ .
2307                                                 ": local proxy caching; {$this->mLastModified} **", 'private' );
2308                                         # start with a shorter timeout for initial testing
2309                                         # header( "Cache-Control: s-maxage=2678400, must-revalidate, max-age=0" );
2310                                         $response->header( "Cache-Control: " .
2311                                                 "s-maxage={$this->mCdnMaxage}, must-revalidate, max-age=0" );
2312                                 }
2313                         } else {
2314                                 # We do want clients to cache if they can, but they *must* check for updates
2315                                 # on revisiting the page.
2316                                 wfDebug( __METHOD__ . ": private caching; {$this->mLastModified} **", 'private' );
2317                                 $response->header( 'Expires: ' . gmdate( 'D, d M Y H:i:s', 0 ) . ' GMT' );
2318                                 $response->header( "Cache-Control: private, must-revalidate, max-age=0" );
2319                         }
2320                         if ( $this->mLastModified ) {
2321                                 $response->header( "Last-Modified: {$this->mLastModified}" );
2322                         }
2323                 } else {
2324                         wfDebug( __METHOD__ . ": no caching **", 'private' );
2325
2326                         # In general, the absence of a last modified header should be enough to prevent
2327                         # the client from using its cache. We send a few other things just to make sure.
2328                         $response->header( 'Expires: ' . gmdate( 'D, d M Y H:i:s', 0 ) . ' GMT' );
2329                         $response->header( 'Cache-Control: no-cache, no-store, max-age=0, must-revalidate' );
2330                         $response->header( 'Pragma: no-cache' );
2331                 }
2332         }
2333
2334         /**
2335          * Transfer styles and JavaScript modules from skin.
2336          *
2337          * @param Skin $sk to load modules for
2338          */
2339         public function loadSkinModules( $sk ) {
2340                 foreach ( $sk->getDefaultModules() as $group => $modules ) {
2341                         if ( $group === 'styles' ) {
2342                                 foreach ( $modules as $key => $moduleMembers ) {
2343                                         $this->addModuleStyles( $moduleMembers );
2344                                 }
2345                         } else {
2346                                 $this->addModules( $modules );
2347                         }
2348                 }
2349         }
2350
2351         /**
2352          * Finally, all the text has been munged and accumulated into
2353          * the object, let's actually output it:
2354          *
2355          * @param bool $return Set to true to get the result as a string rather than sending it
2356          * @return string|null
2357          * @throws Exception
2358          * @throws FatalError
2359          * @throws MWException
2360          */
2361         public function output( $return = false ) {
2362                 global $wgContLang;
2363
2364                 if ( $this->mDoNothing ) {
2365                         return $return ? '' : null;
2366                 }
2367
2368                 $response = $this->getRequest()->response();
2369                 $config = $this->getConfig();
2370
2371                 if ( $this->mRedirect != '' ) {
2372                         # Standards require redirect URLs to be absolute
2373                         $this->mRedirect = wfExpandUrl( $this->mRedirect, PROTO_CURRENT );
2374
2375                         $redirect = $this->mRedirect;
2376                         $code = $this->mRedirectCode;
2377
2378                         if ( Hooks::run( "BeforePageRedirect", [ $this, &$redirect, &$code ] ) ) {
2379                                 if ( $code == '301' || $code == '303' ) {
2380                                         if ( !$config->get( 'DebugRedirects' ) ) {
2381                                                 $response->statusHeader( $code );
2382                                         }
2383                                         $this->mLastModified = wfTimestamp( TS_RFC2822 );
2384                                 }
2385                                 if ( $config->get( 'VaryOnXFP' ) ) {
2386                                         $this->addVaryHeader( 'X-Forwarded-Proto' );
2387                                 }
2388                                 $this->sendCacheControl();
2389
2390                                 $response->header( "Content-Type: text/html; charset=utf-8" );
2391                                 if ( $config->get( 'DebugRedirects' ) ) {
2392                                         $url = htmlspecialchars( $redirect );
2393                                         print "<!DOCTYPE html>\n<html>\n<head>\n<title>Redirect</title>\n</head>\n<body>\n";
2394                                         print "<p>Location: <a href=\"$url\">$url</a></p>\n";
2395                                         print "</body>\n</html>\n";
2396                                 } else {
2397                                         $response->header( 'Location: ' . $redirect );
2398                                 }
2399                         }
2400
2401                         return $return ? '' : null;
2402                 } elseif ( $this->mStatusCode ) {
2403                         $response->statusHeader( $this->mStatusCode );
2404                 }
2405
2406                 # Buffer output; final headers may depend on later processing
2407                 ob_start();
2408
2409                 $response->header( 'Content-type: ' . $config->get( 'MimeType' ) . '; charset=UTF-8' );
2410                 $response->header( 'Content-language: ' . $wgContLang->getHtmlCode() );
2411
2412                 // Avoid Internet Explorer "compatibility view" in IE 8-10, so that
2413                 // jQuery etc. can work correctly.
2414                 $response->header( 'X-UA-Compatible: IE=Edge' );
2415
2416                 if ( !$this->mArticleBodyOnly ) {
2417                         $sk = $this->getSkin();
2418
2419                         if ( $sk->shouldPreloadLogo() ) {
2420                                 $this->addLogoPreloadLinkHeaders();
2421                         }
2422                 }
2423
2424                 $linkHeader = $this->getLinkHeader();
2425                 if ( $linkHeader ) {
2426                         $response->header( $linkHeader );
2427                 }
2428
2429                 // Prevent framing, if requested
2430                 $frameOptions = $this->getFrameOptions();
2431                 if ( $frameOptions ) {
2432                         $response->header( "X-Frame-Options: $frameOptions" );
2433                 }
2434
2435                 if ( $this->mArticleBodyOnly ) {
2436                         echo $this->mBodytext;
2437                 } else {
2438                         // Enable safe mode if requested
2439                         if ( $this->getRequest()->getBool( 'safemode' ) ) {
2440                                 $this->disallowUserJs();
2441                         }
2442
2443                         $sk = $this->getSkin();
2444                         $this->loadSkinModules( $sk );
2445
2446                         MWDebug::addModules( $this );
2447
2448                         // Avoid PHP 7.1 warning of passing $this by reference
2449                         $outputPage = $this;
2450                         // Hook that allows last minute changes to the output page, e.g.
2451                         // adding of CSS or Javascript by extensions.
2452                         Hooks::runWithoutAbort( 'BeforePageDisplay', [ &$outputPage, &$sk ] );
2453
2454                         try {
2455                                 $sk->outputPage();
2456                         } catch ( Exception $e ) {
2457                                 ob_end_clean(); // bug T129657
2458                                 throw $e;
2459                         }
2460                 }
2461
2462                 try {
2463                         // This hook allows last minute changes to final overall output by modifying output buffer
2464                         Hooks::runWithoutAbort( 'AfterFinalPageOutput', [ $this ] );
2465                 } catch ( Exception $e ) {
2466                         ob_end_clean(); // bug T129657
2467                         throw $e;
2468                 }
2469
2470                 $this->sendCacheControl();
2471
2472                 if ( $return ) {
2473                         return ob_get_clean();
2474                 } else {
2475                         ob_end_flush();
2476                         return null;
2477                 }
2478         }
2479
2480         /**
2481          * Prepare this object to display an error page; disable caching and
2482          * indexing, clear the current text and redirect, set the page's title
2483          * and optionally an custom HTML title (content of the "<title>" tag).
2484          *
2485          * @param string|Message $pageTitle Will be passed directly to setPageTitle()
2486          * @param string|Message $htmlTitle Will be passed directly to setHTMLTitle();
2487          *                   optional, if not passed the "<title>" attribute will be
2488          *                   based on $pageTitle
2489          */
2490         public function prepareErrorPage( $pageTitle, $htmlTitle = false ) {
2491                 $this->setPageTitle( $pageTitle );
2492                 if ( $htmlTitle !== false ) {
2493                         $this->setHTMLTitle( $htmlTitle );
2494                 }
2495                 $this->setRobotPolicy( 'noindex,nofollow' );
2496                 $this->setArticleRelated( false );
2497                 $this->enableClientCache( false );
2498                 $this->mRedirect = '';
2499                 $this->clearSubtitle();
2500                 $this->clearHTML();
2501         }
2502
2503         /**
2504          * Output a standard error page
2505          *
2506          * showErrorPage( 'titlemsg', 'pagetextmsg' );
2507          * showErrorPage( 'titlemsg', 'pagetextmsg', [ 'param1', 'param2' ] );
2508          * showErrorPage( 'titlemsg', $messageObject );
2509          * showErrorPage( $titleMessageObject, $messageObject );
2510          *
2511          * @param string|Message $title Message key (string) for page title, or a Message object
2512          * @param string|Message $msg Message key (string) for page text, or a Message object
2513          * @param array $params Message parameters; ignored if $msg is a Message object
2514          */
2515         public function showErrorPage( $title, $msg, $params = [] ) {
2516                 if ( !$title instanceof Message ) {
2517                         $title = $this->msg( $title );
2518                 }
2519
2520                 $this->prepareErrorPage( $title );
2521
2522                 if ( $msg instanceof Message ) {
2523                         if ( $params !== [] ) {
2524                                 trigger_error( 'Argument ignored: $params. The message parameters argument '
2525                                         . 'is discarded when the $msg argument is a Message object instead of '
2526                                         . 'a string.', E_USER_NOTICE );
2527                         }
2528                         $this->addHTML( $msg->parseAsBlock() );
2529                 } else {
2530                         $this->addWikiMsgArray( $msg, $params );
2531                 }
2532
2533                 $this->returnToMain();
2534         }
2535
2536         /**
2537          * Output a standard permission error page
2538          *
2539          * @param array $errors Error message keys or [key, param...] arrays
2540          * @param string $action Action that was denied or null if unknown
2541          */
2542         public function showPermissionsErrorPage( array $errors, $action = null ) {
2543                 foreach ( $errors as $key => $error ) {
2544                         $errors[$key] = (array)$error;
2545                 }
2546
2547                 // For some action (read, edit, create and upload), display a "login to do this action"
2548                 // error if all of the following conditions are met:
2549                 // 1. the user is not logged in
2550                 // 2. the only error is insufficient permissions (i.e. no block or something else)
2551                 // 3. the error can be avoided simply by logging in
2552                 if ( in_array( $action, [ 'read', 'edit', 'createpage', 'createtalk', 'upload' ] )
2553                         && $this->getUser()->isAnon() && count( $errors ) == 1 && isset( $errors[0][0] )
2554                         && ( $errors[0][0] == 'badaccess-groups' || $errors[0][0] == 'badaccess-group0' )
2555                         && ( User::groupHasPermission( 'user', $action )
2556                         || User::groupHasPermission( 'autoconfirmed', $action ) )
2557                 ) {
2558                         $displayReturnto = null;
2559
2560                         # Due to T34276, if a user does not have read permissions,
2561                         # $this->getTitle() will just give Special:Badtitle, which is
2562                         # not especially useful as a returnto parameter. Use the title
2563                         # from the request instead, if there was one.
2564                         $request = $this->getRequest();
2565                         $returnto = Title::newFromText( $request->getVal( 'title', '' ) );
2566                         if ( $action == 'edit' ) {
2567                                 $msg = 'whitelistedittext';
2568                                 $displayReturnto = $returnto;
2569                         } elseif ( $action == 'createpage' || $action == 'createtalk' ) {
2570                                 $msg = 'nocreatetext';
2571                         } elseif ( $action == 'upload' ) {
2572                                 $msg = 'uploadnologintext';
2573                         } else { # Read
2574                                 $msg = 'loginreqpagetext';
2575                                 $displayReturnto = Title::newMainPage();
2576                         }
2577
2578                         $query = [];
2579
2580                         if ( $returnto ) {
2581                                 $query['returnto'] = $returnto->getPrefixedText();
2582
2583                                 if ( !$request->wasPosted() ) {
2584                                         $returntoquery = $request->getValues();
2585                                         unset( $returntoquery['title'] );
2586                                         unset( $returntoquery['returnto'] );
2587                                         unset( $returntoquery['returntoquery'] );
2588                                         $query['returntoquery'] = wfArrayToCgi( $returntoquery );
2589                                 }
2590                         }
2591                         $linkRenderer = MediaWikiServices::getInstance()->getLinkRenderer();
2592                         $loginLink = $linkRenderer->makeKnownLink(
2593                                 SpecialPage::getTitleFor( 'Userlogin' ),
2594                                 $this->msg( 'loginreqlink' )->text(),
2595                                 [],
2596                                 $query
2597                         );
2598
2599                         $this->prepareErrorPage( $this->msg( 'loginreqtitle' ) );
2600                         $this->addHTML( $this->msg( $msg )->rawParams( $loginLink )->parse() );
2601
2602                         # Don't return to a page the user can't read otherwise
2603                         # we'll end up in a pointless loop
2604                         if ( $displayReturnto && $displayReturnto->userCan( 'read', $this->getUser() ) ) {
2605                                 $this->returnToMain( null, $displayReturnto );
2606                         }
2607                 } else {
2608                         $this->prepareErrorPage( $this->msg( 'permissionserrors' ) );
2609                         $this->addWikiText( $this->formatPermissionsErrorMessage( $errors, $action ) );
2610                 }
2611         }
2612
2613         /**
2614          * Display an error page indicating that a given version of MediaWiki is
2615          * required to use it
2616          *
2617          * @param mixed $version The version of MediaWiki needed to use the page
2618          */
2619         public function versionRequired( $version ) {
2620                 $this->prepareErrorPage( $this->msg( 'versionrequired', $version ) );
2621
2622                 $this->addWikiMsg( 'versionrequiredtext', $version );
2623                 $this->returnToMain();
2624         }
2625
2626         /**
2627          * Format a list of error messages
2628          *
2629          * @param array $errors Array of arrays returned by Title::getUserPermissionsErrors
2630          * @param string $action Action that was denied or null if unknown
2631          * @return string The wikitext error-messages, formatted into a list.
2632          */
2633         public function formatPermissionsErrorMessage( array $errors, $action = null ) {
2634                 if ( $action == null ) {
2635                         $text = $this->msg( 'permissionserrorstext', count( $errors ) )->plain() . "\n\n";
2636                 } else {
2637                         $action_desc = $this->msg( "action-$action" )->plain();
2638                         $text = $this->msg(
2639                                 'permissionserrorstext-withaction',
2640                                 count( $errors ),
2641                                 $action_desc
2642                         )->plain() . "\n\n";
2643                 }
2644
2645                 if ( count( $errors ) > 1 ) {
2646                         $text .= '<ul class="permissions-errors">' . "\n";
2647
2648                         foreach ( $errors as $error ) {
2649                                 $text .= '<li>';
2650                                 $text .= call_user_func_array( [ $this, 'msg' ], $error )->plain();
2651                                 $text .= "</li>\n";
2652                         }
2653                         $text .= '</ul>';
2654                 } else {
2655                         $text .= "<div class=\"permissions-errors\">\n" .
2656                                         call_user_func_array( [ $this, 'msg' ], reset( $errors ) )->plain() .
2657                                         "\n</div>";
2658                 }
2659
2660                 return $text;
2661         }
2662
2663         /**
2664          * Show a warning about replica DB lag
2665          *
2666          * If the lag is higher than $wgSlaveLagCritical seconds,
2667          * then the warning is a bit more obvious. If the lag is
2668          * lower than $wgSlaveLagWarning, then no warning is shown.
2669          *
2670          * @param int $lag Slave lag
2671          */
2672         public function showLagWarning( $lag ) {
2673                 $config = $this->getConfig();
2674                 if ( $lag >= $config->get( 'SlaveLagWarning' ) ) {
2675                         $lag = floor( $lag ); // floor to avoid nano seconds to display
2676                         $message = $lag < $config->get( 'SlaveLagCritical' )
2677                                 ? 'lag-warn-normal'
2678                                 : 'lag-warn-high';
2679                         $wrap = Html::rawElement( 'div', [ 'class' => "mw-{$message}" ], "\n$1\n" );
2680                         $this->wrapWikiMsg( "$wrap\n", [ $message, $this->getLanguage()->formatNum( $lag ) ] );
2681                 }
2682         }
2683
2684         public function showFatalError( $message ) {
2685                 $this->prepareErrorPage( $this->msg( 'internalerror' ) );
2686
2687                 $this->addHTML( $message );
2688         }
2689
2690         public function showUnexpectedValueError( $name, $val ) {
2691                 $this->showFatalError( $this->msg( 'unexpected', $name, $val )->text() );
2692         }
2693
2694         public function showFileCopyError( $old, $new ) {
2695                 $this->showFatalError( $this->msg( 'filecopyerror', $old, $new )->text() );
2696         }
2697
2698         public function showFileRenameError( $old, $new ) {
2699                 $this->showFatalError( $this->msg( 'filerenameerror', $old, $new )->text() );
2700         }
2701
2702         public function showFileDeleteError( $name ) {
2703                 $this->showFatalError( $this->msg( 'filedeleteerror', $name )->text() );
2704         }
2705
2706         public function showFileNotFoundError( $name ) {
2707                 $this->showFatalError( $this->msg( 'filenotfound', $name )->text() );
2708         }
2709
2710         /**
2711          * Add a "return to" link pointing to a specified title
2712          *
2713          * @param Title $title Title to link
2714          * @param array $query Query string parameters
2715          * @param string $text Text of the link (input is not escaped)
2716          * @param array $options Options array to pass to Linker
2717          */
2718         public function addReturnTo( $title, array $query = [], $text = null, $options = [] ) {
2719                 $linkRenderer = MediaWikiServices::getInstance()
2720                         ->getLinkRendererFactory()->createFromLegacyOptions( $options );
2721                 $link = $this->msg( 'returnto' )->rawParams(
2722                         $linkRenderer->makeLink( $title, $text, [], $query ) )->escaped();
2723                 $this->addHTML( "<p id=\"mw-returnto\">{$link}</p>\n" );
2724         }
2725
2726         /**
2727          * Add a "return to" link pointing to a specified title,
2728          * or the title indicated in the request, or else the main page
2729          *
2730          * @param mixed $unused
2731          * @param Title|string $returnto Title or String to return to
2732          * @param string $returntoquery Query string for the return to link
2733          */
2734         public function returnToMain( $unused = null, $returnto = null, $returntoquery = null ) {
2735                 if ( $returnto == null ) {
2736                         $returnto = $this->getRequest()->getText( 'returnto' );
2737                 }
2738
2739                 if ( $returntoquery == null ) {
2740                         $returntoquery = $this->getRequest()->getText( 'returntoquery' );
2741                 }
2742
2743                 if ( $returnto === '' ) {
2744                         $returnto = Title::newMainPage();
2745                 }
2746
2747                 if ( is_object( $returnto ) ) {
2748                         $titleObj = $returnto;
2749                 } else {
2750                         $titleObj = Title::newFromText( $returnto );
2751                 }
2752                 // We don't want people to return to external interwiki. That
2753                 // might potentially be used as part of a phishing scheme
2754                 if ( !is_object( $titleObj ) || $titleObj->isExternal() ) {
2755                         $titleObj = Title::newMainPage();
2756                 }
2757
2758                 $this->addReturnTo( $titleObj, wfCgiToArray( $returntoquery ) );
2759         }
2760
2761         private function getRlClientContext() {
2762                 if ( !$this->rlClientContext ) {
2763                         $query = ResourceLoader::makeLoaderQuery(
2764                                 [], // modules; not relevant
2765                                 $this->getLanguage()->getCode(),
2766                                 $this->getSkin()->getSkinName(),
2767                                 $this->getUser()->isLoggedIn() ? $this->getUser()->getName() : null,
2768                                 null, // version; not relevant
2769                                 ResourceLoader::inDebugMode(),
2770                                 null, // only; not relevant
2771                                 $this->isPrintable(),
2772                                 $this->getRequest()->getBool( 'handheld' )
2773                         );
2774                         $this->rlClientContext = new ResourceLoaderContext(
2775                                 $this->getResourceLoader(),
2776                                 new FauxRequest( $query )
2777                         );
2778                         if ( $this->contentOverrideCallbacks ) {
2779                                 $this->rlClientContext = new DerivativeResourceLoaderContext( $this->rlClientContext );
2780                                 $this->rlClientContext->setContentOverrideCallback( function ( Title $title ) {
2781                                         foreach ( $this->contentOverrideCallbacks as $callback ) {
2782                                                 $content = call_user_func( $callback, $title );
2783                                                 if ( $content !== null ) {
2784                                                         return $content;
2785                                                 }
2786                                         }
2787                                         return null;
2788                                 } );
2789                         }
2790                 }
2791                 return $this->rlClientContext;
2792         }
2793
2794         /**
2795          * Call this to freeze the module queue and JS config and create a formatter.
2796          *
2797          * Depending on the Skin, this may get lazy-initialised in either headElement() or
2798          * getBottomScripts(). See SkinTemplate::prepareQuickTemplate(). Calling this too early may
2799          * cause unexpected side-effects since disallowUserJs() may be called at any time to change
2800          * the module filters retroactively. Skins and extension hooks may also add modules until very
2801          * late in the request lifecycle.
2802          *
2803          * @return ResourceLoaderClientHtml
2804          */
2805         public function getRlClient() {
2806                 if ( !$this->rlClient ) {
2807                         $context = $this->getRlClientContext();
2808                         $rl = $this->getResourceLoader();
2809                         $this->addModules( [
2810                                 'user',
2811                                 'user.options',
2812                                 'user.tokens',
2813                         ] );
2814                         $this->addModuleStyles( [
2815                                 'site.styles',
2816                                 'noscript',
2817                                 'user.styles',
2818                         ] );
2819                         $this->getSkin()->setupSkinUserCss( $this );
2820
2821                         // Prepare exempt modules for buildExemptModules()
2822                         $exemptGroups = [ 'site' => [], 'noscript' => [], 'private' => [], 'user' => [] ];
2823                         $exemptStates = [];
2824                         $moduleStyles = $this->getModuleStyles( /*filter*/ true );
2825
2826                         // Preload getTitleInfo for isKnownEmpty calls below and in ResourceLoaderClientHtml
2827                         // Separate user-specific batch for improved cache-hit ratio.
2828                         $userBatch = [ 'user.styles', 'user' ];
2829                         $siteBatch = array_diff( $moduleStyles, $userBatch );
2830                         $dbr = wfGetDB( DB_REPLICA );
2831                         ResourceLoaderWikiModule::preloadTitleInfo( $context, $dbr, $siteBatch );
2832                         ResourceLoaderWikiModule::preloadTitleInfo( $context, $dbr, $userBatch );
2833
2834                         // Filter out modules handled by buildExemptModules()
2835                         $moduleStyles = array_filter( $moduleStyles,
2836                                 function ( $name ) use ( $rl, $context, &$exemptGroups, &$exemptStates ) {
2837                                         $module = $rl->getModule( $name );
2838                                         if ( $module ) {
2839                                                 $group = $module->getGroup();
2840                                                 if ( isset( $exemptGroups[$group] ) ) {
2841                                                         $exemptStates[$name] = 'ready';
2842                                                         if ( !$module->isKnownEmpty( $context ) ) {
2843                                                                 // E.g. Don't output empty <styles>
2844                                                                 $exemptGroups[$group][] = $name;
2845                                                         }
2846                                                         return false;
2847                                                 }
2848                                         }
2849                                         return true;
2850                                 }
2851                         );
2852                         $this->rlExemptStyleModules = $exemptGroups;
2853
2854                         $rlClient = new ResourceLoaderClientHtml( $context, [
2855                                 'target' => $this->getTarget(),
2856                         ] );
2857                         $rlClient->setConfig( $this->getJSVars() );
2858                         $rlClient->setModules( $this->getModules( /*filter*/ true ) );
2859                         $rlClient->setModuleStyles( $moduleStyles );
2860                         $rlClient->setModuleScripts( $this->getModuleScripts( /*filter*/ true ) );
2861                         $rlClient->setExemptStates( $exemptStates );
2862                         $this->rlClient = $rlClient;
2863                 }
2864                 return $this->rlClient;
2865         }
2866
2867         /**
2868          * @param Skin $sk The given Skin
2869          * @param bool $includeStyle Unused
2870          * @return string The doctype, opening "<html>", and head element.
2871          */
2872         public function headElement( Skin $sk, $includeStyle = true ) {
2873                 global $wgContLang;
2874
2875                 $userdir = $this->getLanguage()->getDir();
2876                 $sitedir = $wgContLang->getDir();
2877
2878                 $pieces = [];
2879                 $pieces[] = Html::htmlHeader( Sanitizer::mergeAttributes(
2880                         $this->getRlClient()->getDocumentAttributes(),
2881                         $sk->getHtmlElementAttributes()
2882                 ) );
2883                 $pieces[] = Html::openElement( 'head' );
2884
2885                 if ( $this->getHTMLTitle() == '' ) {
2886                         $this->setHTMLTitle( $this->msg( 'pagetitle', $this->getPageTitle() )->inContentLanguage() );
2887                 }
2888
2889                 if ( !Html::isXmlMimeType( $this->getConfig()->get( 'MimeType' ) ) ) {
2890                         // Add <meta charset="UTF-8">
2891                         // This should be before <title> since it defines the charset used by
2892                         // text including the text inside <title>.
2893                         // The spec recommends defining XHTML5's charset using the XML declaration
2894                         // instead of meta.
2895                         // Our XML declaration is output by Html::htmlHeader.
2896                         // https://html.spec.whatwg.org/multipage/semantics.html#attr-meta-http-equiv-content-type
2897                         // https://html.spec.whatwg.org/multipage/semantics.html#charset
2898                         $pieces[] = Html::element( 'meta', [ 'charset' => 'UTF-8' ] );
2899                 }
2900
2901                 $pieces[] = Html::element( 'title', null, $this->getHTMLTitle() );
2902                 $pieces[] = $this->getRlClient()->getHeadHtml();
2903                 $pieces[] = $this->buildExemptModules();
2904                 $pieces = array_merge( $pieces, array_values( $this->getHeadLinksArray() ) );
2905                 $pieces = array_merge( $pieces, array_values( $this->mHeadItems ) );
2906
2907                 // Use an IE conditional comment to serve the script only to old IE
2908                 $pieces[] = '<!--[if lt IE 9]>' .
2909                         ResourceLoaderClientHtml::makeLoad(
2910                                 ResourceLoaderContext::newDummyContext(),
2911                                 [ 'html5shiv' ],
2912                                 ResourceLoaderModule::TYPE_SCRIPTS,
2913                                 [ 'sync' => true ]
2914                         ) .
2915                         '<![endif]-->';
2916
2917                 $pieces[] = Html::closeElement( 'head' );
2918
2919                 $bodyClasses = $this->mAdditionalBodyClasses;
2920                 $bodyClasses[] = 'mediawiki';
2921
2922                 # Classes for LTR/RTL directionality support
2923                 $bodyClasses[] = $userdir;
2924                 $bodyClasses[] = "sitedir-$sitedir";
2925
2926                 $underline = $this->getUser()->getOption( 'underline' );
2927                 if ( $underline < 2 ) {
2928                         // The following classes can be used here:
2929                         // * mw-underline-always
2930                         // * mw-underline-never
2931                         $bodyClasses[] = 'mw-underline-' . ( $underline ? 'always' : 'never' );
2932                 }
2933
2934                 if ( $this->getLanguage()->capitalizeAllNouns() ) {
2935                         # A <body> class is probably not the best way to do this . . .
2936                         $bodyClasses[] = 'capitalize-all-nouns';
2937                 }
2938
2939                 // Parser feature migration class
2940                 // The idea is that this will eventually be removed, after the wikitext
2941                 // which requires it is cleaned up.
2942                 $bodyClasses[] = 'mw-hide-empty-elt';
2943
2944                 $bodyClasses[] = $sk->getPageClasses( $this->getTitle() );
2945                 $bodyClasses[] = 'skin-' . Sanitizer::escapeClass( $sk->getSkinName() );
2946                 $bodyClasses[] =
2947                         'action-' . Sanitizer::escapeClass( Action::getActionName( $this->getContext() ) );
2948
2949                 $bodyAttrs = [];
2950                 // While the implode() is not strictly needed, it's used for backwards compatibility
2951                 // (this used to be built as a string and hooks likely still expect that).
2952                 $bodyAttrs['class'] = implode( ' ', $bodyClasses );
2953
2954                 // Allow skins and extensions to add body attributes they need
2955                 $sk->addToBodyAttributes( $this, $bodyAttrs );
2956                 Hooks::run( 'OutputPageBodyAttributes', [ $this, $sk, &$bodyAttrs ] );
2957
2958                 $pieces[] = Html::openElement( 'body', $bodyAttrs );
2959
2960                 return self::combineWrappedStrings( $pieces );
2961         }
2962
2963         /**
2964          * Get a ResourceLoader object associated with this OutputPage
2965          *
2966          * @return ResourceLoader
2967          */
2968         public function getResourceLoader() {
2969                 if ( is_null( $this->mResourceLoader ) ) {
2970                         $this->mResourceLoader = new ResourceLoader(
2971                                 $this->getConfig(),
2972                                 LoggerFactory::getInstance( 'resourceloader' )
2973                         );
2974                 }
2975                 return $this->mResourceLoader;
2976         }
2977
2978         /**
2979          * Explicily load or embed modules on a page.
2980          *
2981          * @param array|string $modules One or more module names
2982          * @param string $only ResourceLoaderModule TYPE_ class constant
2983          * @param array $extraQuery [optional] Array with extra query parameters for the request
2984          * @return string|WrappedStringList HTML
2985          */
2986         public function makeResourceLoaderLink( $modules, $only, array $extraQuery = [] ) {
2987                 // Apply 'target' and 'origin' filters
2988                 $modules = $this->filterModules( (array)$modules, null, $only );
2989
2990                 return ResourceLoaderClientHtml::makeLoad(
2991                         $this->getRlClientContext(),
2992                         $modules,
2993                         $only,
2994                         $extraQuery
2995                 );
2996         }
2997
2998         /**
2999          * Combine WrappedString chunks and filter out empty ones
3000          *
3001          * @param array $chunks
3002          * @return string|WrappedStringList HTML
3003          */
3004         protected static function combineWrappedStrings( array $chunks ) {
3005                 // Filter out empty values
3006                 $chunks = array_filter( $chunks, 'strlen' );
3007                 return WrappedString::join( "\n", $chunks );
3008         }
3009
3010         /**
3011          * JS stuff to put at the bottom of the `<body>`.
3012          * These are legacy scripts ($this->mScripts), and user JS.
3013          *
3014          * @return string|WrappedStringList HTML
3015          */
3016         public function getBottomScripts() {
3017                 $chunks = [];
3018                 $chunks[] = $this->getRlClient()->getBodyHtml();
3019
3020                 // Legacy non-ResourceLoader scripts
3021                 $chunks[] = $this->mScripts;
3022
3023                 if ( $this->limitReportJSData ) {
3024                         $chunks[] = ResourceLoader::makeInlineScript(
3025                                 ResourceLoader::makeConfigSetScript(
3026                                         [ 'wgPageParseReport' => $this->limitReportJSData ]
3027                                 )
3028                         );
3029                 }
3030
3031                 return self::combineWrappedStrings( $chunks );
3032         }
3033
3034         /**
3035          * Get the javascript config vars to include on this page
3036          *
3037          * @return array Array of javascript config vars
3038          * @since 1.23
3039          */
3040         public function getJsConfigVars() {
3041                 return $this->mJsConfigVars;
3042         }
3043
3044         /**
3045          * Add one or more variables to be set in mw.config in JavaScript
3046          *
3047          * @param string|array $keys Key or array of key/value pairs
3048          * @param mixed $value [optional] Value of the configuration variable
3049          */
3050         public function addJsConfigVars( $keys, $value = null ) {
3051                 if ( is_array( $keys ) ) {
3052                         foreach ( $keys as $key => $value ) {
3053                                 $this->mJsConfigVars[$key] = $value;
3054                         }
3055                         return;
3056                 }
3057
3058                 $this->mJsConfigVars[$keys] = $value;
3059         }
3060
3061         /**
3062          * Get an array containing the variables to be set in mw.config in JavaScript.
3063          *
3064          * Do not add things here which can be evaluated in ResourceLoaderStartUpModule
3065          * - in other words, page-independent/site-wide variables (without state).
3066          * You will only be adding bloat to the html page and causing page caches to
3067          * have to be purged on configuration changes.
3068          * @return array
3069          */
3070         public function getJSVars() {
3071                 global $wgContLang;
3072
3073                 $curRevisionId = 0;
3074                 $articleId = 0;
3075                 $canonicalSpecialPageName = false; # T23115
3076
3077                 $title = $this->getTitle();
3078                 $ns = $title->getNamespace();
3079                 $canonicalNamespace = MWNamespace::exists( $ns )
3080                         ? MWNamespace::getCanonicalName( $ns )
3081                         : $title->getNsText();
3082
3083                 $sk = $this->getSkin();
3084                 // Get the relevant title so that AJAX features can use the correct page name
3085                 // when making API requests from certain special pages (T36972).
3086                 $relevantTitle = $sk->getRelevantTitle();
3087                 $relevantUser = $sk->getRelevantUser();
3088
3089                 if ( $ns == NS_SPECIAL ) {
3090                         list( $canonicalSpecialPageName, /*...*/ ) =
3091                                 SpecialPageFactory::resolveAlias( $title->getDBkey() );
3092                 } elseif ( $this->canUseWikiPage() ) {
3093                         $wikiPage = $this->getWikiPage();
3094                         $curRevisionId = $wikiPage->getLatest();
3095                         $articleId = $wikiPage->getId();
3096                 }
3097
3098                 $lang = $title->getPageViewLanguage();
3099
3100                 // Pre-process information
3101                 $separatorTransTable = $lang->separatorTransformTable();
3102                 $separatorTransTable = $separatorTransTable ? $separatorTransTable : [];
3103                 $compactSeparatorTransTable = [
3104                         implode( "\t", array_keys( $separatorTransTable ) ),
3105                         implode( "\t", $separatorTransTable ),
3106                 ];
3107                 $digitTransTable = $lang->digitTransformTable();
3108                 $digitTransTable = $digitTransTable ? $digitTransTable : [];
3109                 $compactDigitTransTable = [
3110                         implode( "\t", array_keys( $digitTransTable ) ),
3111                         implode( "\t", $digitTransTable ),
3112                 ];
3113
3114                 $user = $this->getUser();
3115
3116                 $vars = [
3117                         'wgCanonicalNamespace' => $canonicalNamespace,
3118                         'wgCanonicalSpecialPageName' => $canonicalSpecialPageName,
3119                         'wgNamespaceNumber' => $title->getNamespace(),
3120                         'wgPageName' => $title->getPrefixedDBkey(),
3121                         'wgTitle' => $title->getText(),
3122                         'wgCurRevisionId' => $curRevisionId,
3123                         'wgRevisionId' => (int)$this->getRevisionId(),
3124                         'wgArticleId' => $articleId,
3125                         'wgIsArticle' => $this->isArticle(),
3126                         'wgIsRedirect' => $title->isRedirect(),
3127                         'wgAction' => Action::getActionName( $this->getContext() ),
3128                         'wgUserName' => $user->isAnon() ? null : $user->getName(),
3129                         'wgUserGroups' => $user->getEffectiveGroups(),
3130                         'wgCategories' => $this->getCategories(),
3131                         'wgBreakFrames' => $this->getFrameOptions() == 'DENY',
3132                         'wgPageContentLanguage' => $lang->getCode(),
3133                         'wgPageContentModel' => $title->getContentModel(),
3134                         'wgSeparatorTransformTable' => $compactSeparatorTransTable,
3135                         'wgDigitTransformTable' => $compactDigitTransTable,
3136                         'wgDefaultDateFormat' => $lang->getDefaultDateFormat(),
3137                         'wgMonthNames' => $lang->getMonthNamesArray(),
3138                         'wgMonthNamesShort' => $lang->getMonthAbbreviationsArray(),
3139                         'wgRelevantPageName' => $relevantTitle->getPrefixedDBkey(),
3140                         'wgRelevantArticleId' => $relevantTitle->getArticleID(),
3141                         'wgRequestId' => WebRequest::getRequestId(),
3142                 ];
3143
3144                 if ( $user->isLoggedIn() ) {
3145                         $vars['wgUserId'] = $user->getId();
3146                         $vars['wgUserEditCount'] = $user->getEditCount();
3147                         $userReg = $user->getRegistration();
3148                         $vars['wgUserRegistration'] = $userReg ? wfTimestamp( TS_UNIX, $userReg ) * 1000 : null;
3149                         // Get the revision ID of the oldest new message on the user's talk
3150                         // page. This can be used for constructing new message alerts on
3151                         // the client side.
3152                         $vars['wgUserNewMsgRevisionId'] = $user->getNewMessageRevisionId();
3153                 }
3154
3155                 if ( $wgContLang->hasVariants() ) {
3156                         $vars['wgUserVariant'] = $wgContLang->getPreferredVariant();
3157                 }
3158                 // Same test as SkinTemplate
3159                 $vars['wgIsProbablyEditable'] = $title->quickUserCan( 'edit', $user )
3160                         && ( $title->exists() || $title->quickUserCan( 'create', $user ) );
3161
3162                 $vars['wgRelevantPageIsProbablyEditable'] = $relevantTitle
3163                         && $relevantTitle->quickUserCan( 'edit', $user )
3164                         && ( $relevantTitle->exists() || $relevantTitle->quickUserCan( 'create', $user ) );
3165
3166                 foreach ( $title->getRestrictionTypes() as $type ) {
3167                         // Following keys are set in $vars:
3168                         // wgRestrictionCreate, wgRestrictionEdit, wgRestrictionMove, wgRestrictionUpload
3169                         $vars['wgRestriction' . ucfirst( $type )] = $title->getRestrictions( $type );
3170                 }
3171
3172                 if ( $title->isMainPage() ) {
3173                         $vars['wgIsMainPage'] = true;
3174                 }
3175
3176                 if ( $this->mRedirectedFrom ) {
3177                         $vars['wgRedirectedFrom'] = $this->mRedirectedFrom->getPrefixedDBkey();
3178                 }
3179
3180                 if ( $relevantUser ) {
3181                         $vars['wgRelevantUserName'] = $relevantUser->getName();
3182                 }
3183
3184                 // Allow extensions to add their custom variables to the mw.config map.
3185                 // Use the 'ResourceLoaderGetConfigVars' hook if the variable is not
3186                 // page-dependant but site-wide (without state).
3187                 // Alternatively, you may want to use OutputPage->addJsConfigVars() instead.
3188                 Hooks::run( 'MakeGlobalVariablesScript', [ &$vars, $this ] );
3189
3190                 // Merge in variables from addJsConfigVars last
3191                 return array_merge( $vars, $this->getJsConfigVars() );
3192         }
3193
3194         /**
3195          * To make it harder for someone to slip a user a fake
3196          * JavaScript or CSS preview, a random token
3197          * is associated with the login session. If it's not
3198          * passed back with the preview request, we won't render
3199          * the code.
3200          *
3201          * @return bool
3202          */
3203         public function userCanPreview() {
3204                 $request = $this->getRequest();
3205                 if (
3206                         $request->getVal( 'action' ) !== 'submit' ||
3207                         !$request->wasPosted()
3208                 ) {
3209                         return false;
3210                 }
3211
3212                 $user = $this->getUser();
3213
3214                 if ( !$user->isLoggedIn() ) {
3215                         // Anons have predictable edit tokens
3216                         return false;
3217                 }
3218                 if ( !$user->matchEditToken( $request->getVal( 'wpEditToken' ) ) ) {
3219                         return false;
3220                 }
3221
3222                 $title = $this->getTitle();
3223                 $errors = $title->getUserPermissionsErrors( 'edit', $user );
3224                 if ( count( $errors ) !== 0 ) {
3225                         return false;
3226                 }
3227
3228                 return true;
3229         }
3230
3231         /**
3232          * @return array Array in format "link name or number => 'link html'".
3233          */
3234         public function getHeadLinksArray() {
3235                 global $wgVersion;
3236
3237                 $tags = [];
3238                 $config = $this->getConfig();
3239
3240                 $canonicalUrl = $this->mCanonicalUrl;
3241
3242                 $tags['meta-generator'] = Html::element( 'meta', [
3243                         'name' => 'generator',
3244                         'content' => "MediaWiki $wgVersion",
3245                 ] );
3246
3247                 if ( $config->get( 'ReferrerPolicy' ) !== false ) {
3248                         // Per https://w3c.github.io/webappsec-referrer-policy/#unknown-policy-values
3249                         // fallbacks should come before the primary value so we need to reverse the array.
3250                         foreach ( array_reverse( (array)$config->get( 'ReferrerPolicy' ) ) as $i => $policy ) {
3251                                 $tags["meta-referrer-$i"] = Html::element( 'meta', [
3252                                         'name' => 'referrer',
3253                                         'content' => $policy,
3254                                 ] );
3255                         }
3256                 }
3257
3258                 $p = "{$this->mIndexPolicy},{$this->mFollowPolicy}";
3259                 if ( $p !== 'index,follow' ) {
3260                         // http://www.robotstxt.org/wc/meta-user.html
3261                         // Only show if it's different from the default robots policy
3262                         $tags['meta-robots'] = Html::element( 'meta', [
3263                                 'name' => 'robots',
3264                                 'content' => $p,
3265                         ] );
3266                 }
3267
3268                 foreach ( $this->mMetatags as $tag ) {
3269                         if ( strncasecmp( $tag[0], 'http:', 5 ) === 0 ) {
3270                                 $a = 'http-equiv';
3271                                 $tag[0] = substr( $tag[0], 5 );
3272                         } elseif ( strncasecmp( $tag[0], 'og:', 3 ) === 0 ) {
3273                                 $a = 'property';
3274                         } else {
3275                                 $a = 'name';
3276                         }
3277                         $tagName = "meta-{$tag[0]}";
3278                         if ( isset( $tags[$tagName] ) ) {
3279                                 $tagName .= $tag[1];
3280                         }
3281                         $tags[$tagName] = Html::element( 'meta',
3282                                 [
3283                                         $a => $tag[0],
3284                                         'content' => $tag[1]
3285                                 ]
3286                         );
3287                 }
3288
3289                 foreach ( $this->mLinktags as $tag ) {
3290                         $tags[] = Html::element( 'link', $tag );
3291                 }
3292
3293                 # Universal edit button
3294                 if ( $config->get( 'UniversalEditButton' ) && $this->isArticleRelated() ) {
3295                         $user = $this->getUser();
3296                         if ( $this->getTitle()->quickUserCan( 'edit', $user )
3297                                 && ( $this->getTitle()->exists() ||
3298                                         $this->getTitle()->quickUserCan( 'create', $user ) )
3299                         ) {
3300                                 // Original UniversalEditButton
3301                                 $msg = $this->msg( 'edit' )->text();
3302                                 $tags['universal-edit-button'] = Html::element( 'link', [
3303                                         'rel' => 'alternate',
3304                                         'type' => 'application/x-wiki',
3305                                         'title' => $msg,
3306                                         'href' => $this->getTitle()->getEditURL(),
3307                                 ] );
3308                                 // Alternate edit link
3309                                 $tags['alternative-edit'] = Html::element( 'link', [
3310                                         'rel' => 'edit',
3311                                         'title' => $msg,
3312                                         'href' => $this->getTitle()->getEditURL(),
3313                                 ] );
3314                         }
3315                 }
3316
3317                 # Generally the order of the favicon and apple-touch-icon links
3318                 # should not matter, but Konqueror (3.5.9 at least) incorrectly
3319                 # uses whichever one appears later in the HTML source. Make sure
3320                 # apple-touch-icon is specified first to avoid this.
3321                 if ( $config->get( 'AppleTouchIcon' ) !== false ) {
3322                         $tags['apple-touch-icon'] = Html::element( 'link', [
3323                                 'rel' => 'apple-touch-icon',
3324                                 'href' => $config->get( 'AppleTouchIcon' )
3325                         ] );
3326                 }
3327
3328                 if ( $config->get( 'Favicon' ) !== false ) {
3329                         $tags['favicon'] = Html::element( 'link', [
3330                                 'rel' => 'shortcut icon',
3331                                 'href' => $config->get( 'Favicon' )
3332                         ] );
3333                 }
3334
3335                 # OpenSearch description link
3336                 $tags['opensearch'] = Html::element( 'link', [
3337                         'rel' => 'search',
3338                         'type' => 'application/opensearchdescription+xml',
3339                         'href' => wfScript( 'opensearch_desc' ),
3340                         'title' => $this->msg( 'opensearch-desc' )->inContentLanguage()->text(),
3341                 ] );
3342
3343                 # Real Simple Discovery link, provides auto-discovery information
3344                 # for the MediaWiki API (and potentially additional custom API
3345                 # support such as WordPress or Twitter-compatible APIs for a
3346                 # blogging extension, etc)
3347                 $tags['rsd'] = Html::element( 'link', [
3348                         'rel' => 'EditURI',
3349                         'type' => 'application/rsd+xml',
3350                         // Output a protocol-relative URL here if $wgServer is protocol-relative.
3351                         // Whether RSD accepts relative or protocol-relative URLs is completely
3352                         // undocumented, though.
3353                         'href' => wfExpandUrl( wfAppendQuery(
3354                                 wfScript( 'api' ),
3355                                 [ 'action' => 'rsd' ] ),
3356                                 PROTO_RELATIVE
3357                         ),
3358                 ] );
3359
3360                 # Language variants
3361                 if ( !$config->get( 'DisableLangConversion' ) ) {
3362                         $lang = $this->getTitle()->getPageLanguage();
3363                         if ( $lang->hasVariants() ) {
3364                                 $variants = $lang->getVariants();
3365                                 foreach ( $variants as $variant ) {
3366                                         $tags["variant-$variant"] = Html::element( 'link', [
3367                                                 'rel' => 'alternate',
3368                                                 'hreflang' => LanguageCode::bcp47( $variant ),
3369                                                 'href' => $this->getTitle()->getLocalURL(
3370                                                         [ 'variant' => $variant ] )
3371                                                 ]
3372                                         );
3373                                 }
3374                                 # x-default link per https://support.google.com/webmasters/answer/189077?hl=en
3375                                 $tags["variant-x-default"] = Html::element( 'link', [
3376                                         'rel' => 'alternate',
3377                                         'hreflang' => 'x-default',
3378                                         'href' => $this->getTitle()->getLocalURL() ] );
3379                         }
3380                 }
3381
3382                 # Copyright
3383                 if ( $this->copyrightUrl !== null ) {
3384                         $copyright = $this->copyrightUrl;
3385                 } else {
3386                         $copyright = '';
3387                         if ( $config->get( 'RightsPage' ) ) {
3388                                 $copy = Title::newFromText( $config->get( 'RightsPage' ) );
3389
3390                                 if ( $copy ) {
3391                                         $copyright = $copy->getLocalURL();
3392                                 }
3393                         }
3394
3395                         if ( !$copyright && $config->get( 'RightsUrl' ) ) {
3396                                 $copyright = $config->get( 'RightsUrl' );
3397                         }
3398                 }
3399
3400                 if ( $copyright ) {
3401                         $tags['copyright'] = Html::element( 'link', [
3402                                 'rel' => 'license',
3403                                 'href' => $copyright ]
3404                         );
3405                 }
3406
3407                 # Feeds
3408                 if ( $config->get( 'Feed' ) ) {
3409                         $feedLinks = [];
3410
3411                         foreach ( $this->getSyndicationLinks() as $format => $link ) {
3412                                 # Use the page name for the title.  In principle, this could
3413                                 # lead to issues with having the same name for different feeds
3414                                 # corresponding to the same page, but we can't avoid that at
3415                                 # this low a level.
3416
3417                                 $feedLinks[] = $this->feedLink(
3418                                         $format,
3419                                         $link,
3420                                         # Used messages: 'page-rss-feed' and 'page-atom-feed' (for an easier grep)
3421                                         $this->msg(
3422                                                 "page-{$format}-feed", $this->getTitle()->getPrefixedText()
3423                                         )->text()
3424                                 );
3425                         }
3426
3427                         # Recent changes feed should appear on every page (except recentchanges,
3428                         # that would be redundant). Put it after the per-page feed to avoid
3429                         # changing existing behavior. It's still available, probably via a
3430                         # menu in your browser. Some sites might have a different feed they'd
3431                         # like to promote instead of the RC feed (maybe like a "Recent New Articles"
3432                         # or "Breaking news" one). For this, we see if $wgOverrideSiteFeed is defined.
3433                         # If so, use it instead.
3434                         $sitename = $config->get( 'Sitename' );
3435                         if ( $config->get( 'OverrideSiteFeed' ) ) {
3436                                 foreach ( $config->get( 'OverrideSiteFeed' ) as $type => $feedUrl ) {
3437                                         // Note, this->feedLink escapes the url.
3438                                         $feedLinks[] = $this->feedLink(
3439                                                 $type,
3440                                                 $feedUrl,
3441                                                 $this->msg( "site-{$type}-feed", $sitename )->text()
3442                                         );
3443                                 }
3444                         } elseif ( !$this->getTitle()->isSpecial( 'Recentchanges' ) ) {
3445                                 $rctitle = SpecialPage::getTitleFor( 'Recentchanges' );
3446                                 foreach ( $config->get( 'AdvertisedFeedTypes' ) as $format ) {
3447                                         $feedLinks[] = $this->feedLink(
3448                                                 $format,
3449                                                 $rctitle->getLocalURL( [ 'feed' => $format ] ),
3450                                                 # For grep: 'site-rss-feed', 'site-atom-feed'
3451                                                 $this->msg( "site-{$format}-feed", $sitename )->text()
3452                                         );
3453                                 }
3454                         }
3455
3456                         # Allow extensions to change the list pf feeds. This hook is primarily for changing,
3457                         # manipulating or removing existing feed tags. If you want to add new feeds, you should
3458                         # use OutputPage::addFeedLink() instead.
3459                         Hooks::run( 'AfterBuildFeedLinks', [ &$feedLinks ] );
3460
3461                         $tags += $feedLinks;
3462                 }
3463
3464                 # Canonical URL
3465                 if ( $config->get( 'EnableCanonicalServerLink' ) ) {
3466                         if ( $canonicalUrl !== false ) {
3467                                 $canonicalUrl = wfExpandUrl( $canonicalUrl, PROTO_CANONICAL );
3468                         } else {
3469                                 if ( $this->isArticleRelated() ) {
3470                                         // This affects all requests where "setArticleRelated" is true. This is
3471                                         // typically all requests that show content (query title, curid, oldid, diff),
3472                                         // and all wikipage actions (edit, delete, purge, info, history etc.).
3473                                         // It does not apply to File pages and Special pages.
3474                                         // 'history' and 'info' actions address page metadata rather than the page
3475                                         // content itself, so they may not be canonicalized to the view page url.
3476                                         // TODO: this ought to be better encapsulated in the Action class.
3477                                         $action = Action::getActionName( $this->getContext() );
3478                                         if ( in_array( $action, [ 'history', 'info' ] ) ) {
3479                                                 $query = "action={$action}";
3480                                         } else {
3481                                                 $query = '';
3482                                         }
3483                                         $canonicalUrl = $this->getTitle()->getCanonicalURL( $query );
3484                                 } else {
3485                                         $reqUrl = $this->getRequest()->getRequestURL();
3486                                         $canonicalUrl = wfExpandUrl( $reqUrl, PROTO_CANONICAL );
3487                                 }
3488                         }
3489                 }
3490                 if ( $canonicalUrl !== false ) {
3491                         $tags[] = Html::element( 'link', [
3492                                 'rel' => 'canonical',
3493                                 'href' => $canonicalUrl
3494                         ] );
3495                 }
3496
3497                 return $tags;
3498         }
3499
3500         /**
3501          * Generate a "<link rel/>" for a feed.
3502          *
3503          * @param string $type Feed type
3504          * @param string $url URL to the feed
3505          * @param string $text Value of the "title" attribute
3506          * @return string HTML fragment
3507          */
3508         private function feedLink( $type, $url, $text ) {
3509                 return Html::element( 'link', [
3510                         'rel' => 'alternate',
3511                         'type' => "application/$type+xml",
3512                         'title' => $text,
3513                         'href' => $url ]
3514                 );
3515         }
3516
3517         /**
3518          * Add a local or specified stylesheet, with the given media options.
3519          * Internal use only. Use OutputPage::addModuleStyles() if possible.
3520          *
3521          * @param string $style URL to the file
3522          * @param string $media To specify a media type, 'screen', 'printable', 'handheld' or any.
3523          * @param string $condition For IE conditional comments, specifying an IE version
3524          * @param string $dir Set to 'rtl' or 'ltr' for direction-specific sheets
3525          */
3526         public function addStyle( $style, $media = '', $condition = '', $dir = '' ) {
3527                 $options = [];
3528                 if ( $media ) {
3529                         $options['media'] = $media;
3530                 }
3531                 if ( $condition ) {
3532                         $options['condition'] = $condition;
3533                 }
3534                 if ( $dir ) {
3535                         $options['dir'] = $dir;
3536                 }
3537                 $this->styles[$style] = $options;
3538         }
3539
3540         /**
3541          * Adds inline CSS styles
3542          * Internal use only. Use OutputPage::addModuleStyles() if possible.
3543          *
3544          * @param mixed $style_css Inline CSS
3545          * @param string $flip Set to 'flip' to flip the CSS if needed
3546          */
3547         public function addInlineStyle( $style_css, $flip = 'noflip' ) {
3548                 if ( $flip === 'flip' && $this->getLanguage()->isRTL() ) {
3549                         # If wanted, and the interface is right-to-left, flip the CSS
3550                         $style_css = CSSJanus::transform( $style_css, true, false );
3551                 }
3552                 $this->mInlineStyles .= Html::inlineStyle( $style_css );
3553         }
3554
3555         /**
3556          * Build exempt modules and legacy non-ResourceLoader styles.
3557          *
3558          * @return string|WrappedStringList HTML
3559          */
3560         protected function buildExemptModules() {
3561                 $chunks = [];
3562                 // Things that go after the ResourceLoaderDynamicStyles marker
3563                 $append = [];
3564
3565                 // We want site, private and user styles to override dynamically added styles from
3566                 // general modules, but we want dynamically added styles to override statically added
3567                 // style modules. So the order has to be:
3568                 // - page style modules (formatted by ResourceLoaderClientHtml::getHeadHtml())
3569                 // - dynamically loaded styles (added by mw.loader before ResourceLoaderDynamicStyles)
3570                 // - ResourceLoaderDynamicStyles marker
3571                 // - site/private/user styles
3572
3573                 // Add legacy styles added through addStyle()/addInlineStyle() here
3574                 $chunks[] = implode( '', $this->buildCssLinksArray() ) . $this->mInlineStyles;
3575
3576                 $chunks[] = Html::element(
3577                         'meta',
3578                         [ 'name' => 'ResourceLoaderDynamicStyles', 'content' => '' ]
3579                 );
3580
3581                 $separateReq = [ 'site.styles', 'user.styles' ];
3582                 foreach ( $this->rlExemptStyleModules as $group => $moduleNames ) {
3583                         // Combinable modules
3584                         $chunks[] = $this->makeResourceLoaderLink(
3585                                 array_diff( $moduleNames, $separateReq ),
3586                                 ResourceLoaderModule::TYPE_STYLES
3587                         );
3588
3589                         foreach ( array_intersect( $moduleNames, $separateReq ) as $name ) {
3590                                 // These require their own dedicated request in order to support "@import"
3591                                 // syntax, which is incompatible with concatenation. (T147667, T37562)
3592                                 $chunks[] = $this->makeResourceLoaderLink( $name,
3593                                         ResourceLoaderModule::TYPE_STYLES
3594                                 );
3595                         }
3596                 }
3597
3598                 return self::combineWrappedStrings( array_merge( $chunks, $append ) );
3599         }
3600
3601         /**
3602          * @return array
3603          */
3604         public function buildCssLinksArray() {
3605                 $links = [];
3606
3607                 foreach ( $this->styles as $file => $options ) {
3608                         $link = $this->styleLink( $file, $options );
3609                         if ( $link ) {
3610                                 $links[$file] = $link;
3611                         }
3612                 }
3613                 return $links;
3614         }
3615
3616         /**
3617          * Generate \<link\> tags for stylesheets
3618          *
3619          * @param string $style URL to the file
3620          * @param array $options Option, can contain 'condition', 'dir', 'media' keys
3621          * @return string HTML fragment
3622          */
3623         protected function styleLink( $style, array $options ) {
3624                 if ( isset( $options['dir'] ) ) {
3625                         if ( $this->getLanguage()->getDir() != $options['dir'] ) {
3626                                 return '';
3627                         }
3628                 }
3629
3630                 if ( isset( $options['media'] ) ) {
3631                         $media = self::transformCssMedia( $options['media'] );
3632                         if ( is_null( $media ) ) {
3633                                 return '';
3634                         }
3635                 } else {
3636                         $media = 'all';
3637                 }
3638
3639                 if ( substr( $style, 0, 1 ) == '/' ||
3640                         substr( $style, 0, 5 ) == 'http:' ||
3641                         substr( $style, 0, 6 ) == 'https:' ) {
3642                         $url = $style;
3643                 } else {
3644                         $config = $this->getConfig();
3645                         $url = $config->get( 'StylePath' ) . '/' . $style . '?' .
3646                                 $config->get( 'StyleVersion' );
3647                 }
3648
3649                 $link = Html::linkedStyle( $url, $media );
3650
3651                 if ( isset( $options['condition'] ) ) {
3652                         $condition = htmlspecialchars( $options['condition'] );
3653                         $link = "<!--[if $condition]>$link<![endif]-->";
3654                 }
3655                 return $link;
3656         }
3657
3658         /**
3659          * Transform path to web-accessible static resource.
3660          *
3661          * This is used to add a validation hash as query string.
3662          * This aids various behaviors:
3663          *
3664          * - Put long Cache-Control max-age headers on responses for improved
3665          *   cache performance.
3666          * - Get the correct version of a file as expected by the current page.
3667          * - Instantly get the updated version of a file after deployment.
3668          *
3669          * Avoid using this for urls included in HTML as otherwise clients may get different
3670          * versions of a resource when navigating the site depending on when the page was cached.
3671          * If changes to the url propagate, this is not a problem (e.g. if the url is in
3672          * an external stylesheet).
3673          *
3674          * @since 1.27
3675          * @param Config $config
3676          * @param string $path Path-absolute URL to file (from document root, must start with "/")
3677          * @return string URL
3678          */
3679         public static function transformResourcePath( Config $config, $path ) {
3680                 global $IP;
3681
3682                 $localDir = $IP;
3683                 $remotePathPrefix = $config->get( 'ResourceBasePath' );
3684                 if ( $remotePathPrefix === '' ) {
3685                         // The configured base path is required to be empty string for
3686                         // wikis in the domain root
3687                         $remotePath = '/';
3688                 } else {
3689                         $remotePath = $remotePathPrefix;
3690                 }
3691                 if ( strpos( $path, $remotePath ) !== 0 || substr( $path, 0, 2 ) === '//' ) {
3692                         // - Path is outside wgResourceBasePath, ignore.
3693                         // - Path is protocol-relative. Fixes T155310. Not supported by RelPath lib.
3694                         return $path;
3695                 }
3696                 // For files in resources, extensions/ or skins/, ResourceBasePath is preferred here.
3697                 // For other misc files in $IP, we'll fallback to that as well. There is, however, a fourth
3698                 // supported dir/path pair in the configuration (wgUploadDirectory, wgUploadPath)
3699                 // which is not expected to be in wgResourceBasePath on CDNs. (T155146)
3700                 $uploadPath = $config->get( 'UploadPath' );
3701                 if ( strpos( $path, $uploadPath ) === 0 ) {
3702                         $localDir = $config->get( 'UploadDirectory' );
3703                         $remotePathPrefix = $remotePath = $uploadPath;
3704                 }
3705
3706                 $path = RelPath::getRelativePath( $path, $remotePath );
3707                 return self::transformFilePath( $remotePathPrefix, $localDir, $path );
3708         }
3709
3710         /**
3711          * Utility method for transformResourceFilePath().
3712          *
3713          * Caller is responsible for ensuring the file exists. Emits a PHP warning otherwise.
3714          *
3715          * @since 1.27
3716          * @param string $remotePathPrefix URL path prefix that points to $localPath
3717          * @param string $localPath File directory exposed at $remotePath
3718          * @param string $file Path to target file relative to $localPath
3719          * @return string URL
3720          */
3721         public static function transformFilePath( $remotePathPrefix, $localPath, $file ) {
3722                 $hash = md5_file( "$localPath/$file" );
3723                 if ( $hash === false ) {
3724                         wfLogWarning( __METHOD__ . ": Failed to hash $localPath/$file" );
3725                         $hash = '';
3726                 }
3727                 return "$remotePathPrefix/$file?" . substr( $hash, 0, 5 );
3728         }
3729
3730         /**
3731          * Transform "media" attribute based on request parameters
3732          *
3733          * @param string $media Current value of the "media" attribute
3734          * @return string Modified value of the "media" attribute, or null to skip
3735          * this stylesheet
3736          */
3737         public static function transformCssMedia( $media ) {
3738                 global $wgRequest;
3739
3740                 // https://www.w3.org/TR/css3-mediaqueries/#syntax
3741                 $screenMediaQueryRegex = '/^(?:only\s+)?screen\b/i';
3742
3743                 // Switch in on-screen display for media testing
3744                 $switches = [
3745                         'printable' => 'print',
3746                         'handheld' => 'handheld',
3747                 ];
3748                 foreach ( $switches as $switch => $targetMedia ) {
3749                         if ( $wgRequest->getBool( $switch ) ) {
3750                                 if ( $media == $targetMedia ) {
3751                                         $media = '';
3752                                 } elseif ( preg_match( $screenMediaQueryRegex, $media ) === 1 ) {
3753                                         /* This regex will not attempt to understand a comma-separated media_query_list
3754                                          *
3755                                          * Example supported values for $media:
3756                                          * 'screen', 'only screen', 'screen and (min-width: 982px)' ),
3757                                          * Example NOT supported value for $media:
3758                                          * '3d-glasses, screen, print and resolution > 90dpi'
3759                                          *
3760                                          * If it's a print request, we never want any kind of screen stylesheets
3761                                          * If it's a handheld request (currently the only other choice with a switch),
3762                                          * we don't want simple 'screen' but we might want screen queries that
3763                                          * have a max-width or something, so we'll pass all others on and let the
3764                                          * client do the query.
3765                                          */
3766                                         if ( $targetMedia == 'print' || $media == 'screen' ) {
3767                                                 return null;
3768                                         }
3769                                 }
3770                         }
3771                 }
3772
3773                 return $media;
3774         }
3775
3776         /**
3777          * Add a wikitext-formatted message to the output.
3778          * This is equivalent to:
3779          *
3780          *    $wgOut->addWikiText( wfMessage( ... )->plain() )
3781          */
3782         public function addWikiMsg( /*...*/ ) {
3783                 $args = func_get_args();
3784                 $name = array_shift( $args );
3785                 $this->addWikiMsgArray( $name, $args );
3786         }
3787
3788         /**
3789          * Add a wikitext-formatted message to the output.
3790          * Like addWikiMsg() except the parameters are taken as an array
3791          * instead of a variable argument list.
3792          *
3793          * @param string $name
3794          * @param array $args
3795          */
3796         public function addWikiMsgArray( $name, $args ) {
3797                 $this->addHTML( $this->msg( $name, $args )->parseAsBlock() );
3798         }
3799
3800         /**
3801          * This function takes a number of message/argument specifications, wraps them in
3802          * some overall structure, and then parses the result and adds it to the output.
3803          *
3804          * In the $wrap, $1 is replaced with the first message, $2 with the second,
3805          * and so on. The subsequent arguments may be either
3806          * 1) strings, in which case they are message names, or
3807          * 2) arrays, in which case, within each array, the first element is the message
3808          *    name, and subsequent elements are the parameters to that message.
3809          *
3810          * Don't use this for messages that are not in the user's interface language.
3811          *
3812          * For example:
3813          *
3814          *    $wgOut->wrapWikiMsg( "<div class='error'>\n$1\n</div>", 'some-error' );
3815          *
3816          * Is equivalent to:
3817          *
3818          *    $wgOut->addWikiText( "<div class='error'>\n"
3819          *        . wfMessage( 'some-error' )->plain() . "\n</div>" );
3820          *
3821          * The newline after the opening div is needed in some wikitext. See T21226.
3822          *
3823          * @param string $wrap
3824          */
3825         public function wrapWikiMsg( $wrap /*, ...*/ ) {
3826                 $msgSpecs = func_get_args();
3827                 array_shift( $msgSpecs );
3828                 $msgSpecs = array_values( $msgSpecs );
3829                 $s = $wrap;
3830                 foreach ( $msgSpecs as $n => $spec ) {
3831                         if ( is_array( $spec ) ) {
3832                                 $args = $spec;
3833                                 $name = array_shift( $args );
3834                                 if ( isset( $args['options'] ) ) {
3835                                         unset( $args['options'] );
3836                                         wfDeprecated(
3837                                                 'Adding "options" to ' . __METHOD__ . ' is no longer supported',
3838                                                 '1.20'
3839                                         );
3840                                 }
3841                         } else {
3842                                 $args = [];
3843                                 $name = $spec;
3844                         }
3845                         $s = str_replace( '$' . ( $n + 1 ), $this->msg( $name, $args )->plain(), $s );
3846                 }
3847                 $this->addWikiText( $s );
3848         }
3849
3850         /**
3851          * Whether the output has a table of contents
3852          * @return bool
3853          * @since 1.22
3854          */
3855         public function isTOCEnabled() {
3856                 return $this->mEnableTOC;
3857         }
3858
3859         /**
3860          * Enables/disables section edit links, doesn't override __NOEDITSECTION__
3861          * @param bool $flag
3862          * @since 1.23
3863          * @deprecated since 1.31, use $poOptions to addParserOutput() instead.
3864          */
3865         public function enableSectionEditLinks( $flag = true ) {
3866                 wfDeprecated( __METHOD__, '1.31' );
3867         }
3868
3869         /**
3870          * @return bool
3871          * @since 1.23
3872          * @deprecated since 1.31, use $poOptions to addParserOutput() instead.
3873          */
3874         public function sectionEditLinksEnabled() {
3875                 wfDeprecated( __METHOD__, '1.31' );
3876                 return true;
3877         }
3878
3879         /**
3880          * Helper function to setup the PHP implementation of OOUI to use in this request.
3881          *
3882          * @since 1.26
3883          * @param String $skinName The Skin name to determine the correct OOUI theme
3884          * @param String $dir Language direction
3885          */
3886         public static function setupOOUI( $skinName = 'default', $dir = 'ltr' ) {
3887                 $themes = ResourceLoaderOOUIModule::getSkinThemeMap();
3888                 $theme = isset( $themes[$skinName] ) ? $themes[$skinName] : $themes['default'];
3889                 // For example, 'OOUI\WikimediaUITheme'.
3890                 $themeClass = "OOUI\\{$theme}Theme";
3891                 OOUI\Theme::setSingleton( new $themeClass() );
3892                 OOUI\Element::setDefaultDir( $dir );
3893         }
3894
3895         /**
3896          * Add ResourceLoader module styles for OOUI and set up the PHP implementation of it for use with
3897          * MediaWiki and this OutputPage instance.
3898          *
3899          * @since 1.25
3900          */
3901         public function enableOOUI() {
3902                 self::setupOOUI(
3903                         strtolower( $this->getSkin()->getSkinName() ),
3904                         $this->getLanguage()->getDir()
3905                 );
3906                 $this->addModuleStyles( [
3907                         'oojs-ui-core.styles',
3908                         'oojs-ui.styles.indicators',
3909                         'oojs-ui.styles.textures',
3910                         'mediawiki.widgets.styles',
3911                         'oojs-ui.styles.icons-content',
3912                         'oojs-ui.styles.icons-alerts',
3913                         'oojs-ui.styles.icons-interactions',
3914                 ] );
3915         }
3916
3917         /**
3918          * Add Link headers for preloading the wiki's logo.
3919          *
3920          * @since 1.26
3921          */
3922         protected function addLogoPreloadLinkHeaders() {
3923                 $logo = ResourceLoaderSkinModule::getLogo( $this->getConfig() );
3924
3925                 $tags = [];
3926                 $logosPerDppx = [];
3927                 $logos = [];
3928
3929                 if ( !is_array( $logo ) ) {
3930                         // No media queries required if we only have one variant
3931                         $this->addLinkHeader( '<' . $logo . '>;rel=preload;as=image' );
3932                         return;
3933                 }
3934
3935                 if ( isset( $logo['svg'] ) ) {
3936                         // No media queries required if we only have a 1x and svg variant
3937                         // because all preload-capable browsers support SVGs
3938                         $this->addLinkHeader( '<' . $logo['svg'] . '>;rel=preload;as=image' );
3939                         return;
3940                 }
3941
3942                 foreach ( $logo as $dppx => $src ) {
3943                         // Keys are in this format: "1.5x"
3944                         $dppx = substr( $dppx, 0, -1 );
3945                         $logosPerDppx[$dppx] = $src;
3946                 }
3947
3948                 // Because PHP can't have floats as array keys
3949                 uksort( $logosPerDppx, function ( $a , $b ) {
3950                         $a = floatval( $a );
3951                         $b = floatval( $b );
3952
3953                         if ( $a == $b ) {
3954                                 return 0;
3955                         }
3956                         // Sort from smallest to largest (e.g. 1x, 1.5x, 2x)
3957                         return ( $a < $b ) ? -1 : 1;
3958                 } );
3959
3960                 foreach ( $logosPerDppx as $dppx => $src ) {
3961                         $logos[] = [ 'dppx' => $dppx, 'src' => $src ];
3962                 }
3963
3964                 $logosCount = count( $logos );
3965                 // Logic must match ResourceLoaderSkinModule:
3966                 // - 1x applies to resolution < 1.5dppx
3967                 // - 1.5x applies to resolution >= 1.5dppx && < 2dppx
3968                 // - 2x applies to resolution >= 2dppx
3969                 // Note that min-resolution and max-resolution are both inclusive.
3970                 for ( $i = 0; $i < $logosCount; $i++ ) {
3971                         if ( $i === 0 ) {
3972                                 // Smallest dppx
3973                                 // min-resolution is ">=" (larger than or equal to)
3974                                 // "not min-resolution" is essentially "<"
3975                                 $media_query = 'not all and (min-resolution: ' . $logos[ 1 ]['dppx'] . 'dppx)';
3976                         } elseif ( $i !== $logosCount - 1 ) {
3977                                 // In between
3978                                 // Media query expressions can only apply "not" to the entire expression
3979                                 // (e.g. can't express ">= 1.5 and not >= 2).
3980                                 // Workaround: Use <= 1.9999 in place of < 2.
3981                                 $upper_bound = floatval( $logos[ $i + 1 ]['dppx'] ) - 0.000001;
3982                                 $media_query = '(min-resolution: ' . $logos[ $i ]['dppx'] .
3983                                         'dppx) and (max-resolution: ' . $upper_bound . 'dppx)';
3984                         } else {
3985                                 // Largest dppx
3986                                 $media_query = '(min-resolution: ' . $logos[ $i ]['dppx'] . 'dppx)';
3987                         }
3988
3989                         $this->addLinkHeader(
3990                                 '<' . $logos[$i]['src'] . '>;rel=preload;as=image;media=' . $media_query
3991                         );
3992                 }
3993         }
3994 }