OutputPage.php

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<?php
namespace MediaWiki\Output;
 
use Article;
use Content;
use CSSJanus;
use Exception;
use ExtensionRegistry;
use File;
use HtmlArmor;
use InvalidArgumentException;
use Language;
use LanguageCode;
use MediaWiki\Cache\LinkCache;
use MediaWiki\Config\Config;
use MediaWiki\Content\JavaScriptContent;
use MediaWiki\Content\TextContent;
use MediaWiki\Context\ContextSource;
use MediaWiki\Context\IContextSource;
use MediaWiki\Context\RequestContext;
use MediaWiki\Debug\MWDebug;
use MediaWiki\HookContainer\ProtectedHookAccessorTrait;
use MediaWiki\Html\Html;
use MediaWiki\Linker\LinkTarget;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Message\Message;
use MediaWiki\Page\PageRecord;
use MediaWiki\Page\PageReference;
use MediaWiki\Parser\Parser;
use MediaWiki\Parser\ParserOutput;
use MediaWiki\Parser\ParserOutputFlags;
use MediaWiki\Parser\Sanitizer;
use MediaWiki\Permissions\PermissionStatus;
use MediaWiki\Request\ContentSecurityPolicy;
use MediaWiki\Request\FauxRequest;
use MediaWiki\Request\WebRequest;
use MediaWiki\ResourceLoader as RL;
use MediaWiki\ResourceLoader\ResourceLoader;
use MediaWiki\Session\SessionManager;
use MediaWiki\SpecialPage\SpecialPage;
use MediaWiki\Title\Title;
use MediaWiki\Title\TitleValue;
use MediaWiki\Utils\MWTimestamp;
use MessageSpecifier;
use OOUI\Element;
use OOUI\Theme;
use ParserOptions;
use RuntimeException;
use Skin;
use Wikimedia\AtEase\AtEase;
use Wikimedia\Bcp47Code\Bcp47Code;
use Wikimedia\LightweightObjectStore\ExpirationAwareness;
use Wikimedia\Parsoid\Core\TOCData;
use Wikimedia\Rdbms\IResultWrapper;
use Wikimedia\RelPath;
use Wikimedia\WrappedString;
use Wikimedia\WrappedStringList;
 
class OutputPage extends ContextSource {
    use ProtectedHookAccessorTrait;
 
    public const CSP_HEADERS = 'headers';
    public const CSP_META = 'meta';
 
    // Constants for getJSVars()
    private const JS_VAR_EARLY = 1;
    private const JS_VAR_LATE = 2;
 
    // Core config vars that opt-in to JS_VAR_LATE.
    // Extensions use the 'LateJSConfigVarNames' attribute instead.
    private const CORE_LATE_JS_CONFIG_VAR_NAMES = [];
 
    private static $oouiSetupDone = false;
 
    protected $mMetatags = [];
 
    protected $mLinktags = [];
 
    protected $mCanonicalUrl = false;
 
    private $mPageTitle = '';
 
    private $displayTitle;
 
    private $cacheIsFinal = false;
 
    public $mBodytext = '';
 
    private $mHTMLtitle = '';
 
    private $mIsArticle = false;
 
    private $mIsArticleRelated = true;
 
    private $mHasCopyright = false;
 
    private $mPrintable = false;
 
    private $tocData;
 
    private $mSubtitle = [];
 
    public $mRedirect = '';
 
    protected $mStatusCode;
 
    protected $mLastModified = '';
 
    protected $mCategoryLinks = [];
 
    protected $mCategories = [
        'hidden' => [],
        'normal' => [],
    ];
 
    protected $mIndicators = [];
 
    private $mLanguageLinks = [];
 
    private $mScripts = '';
 
    protected $mInlineStyles = '';
 
    protected $mAdditionalHtmlClasses = [];
 
    protected $mHeadItems = [];
 
    protected $mAdditionalBodyClasses = [];
 
    protected $mModules = [];
 
    protected $mModuleStyles = [];
 
    protected $mResourceLoader;
 
    private $rlClient;
 
    private $rlClientContext;
 
    private $rlExemptStyleModules;
 
    protected $mJsConfigVars = [];
 
    protected $mTemplateIds = [];
 
    protected $mImageTimeKeys = [];
 
    public $mRedirectCode = '';
 
    protected $mFeedLinksAppendQuery = null;
 
    protected $mAllowedModules = [
        RL\Module::TYPE_COMBINED => RL\Module::ORIGIN_ALL,
    ];
 
    protected $mDoNothing = false;
 
    // Parser related.
 
    protected $mParserOptions = null;
 
    private $mFeedLinks = [];
 
    protected $mEnableClientCache = true;
 
    private $mArticleBodyOnly = false;
 
    protected $mNewSectionLink = false;
 
    protected $mHideNewSectionLink = false;
 
    public $mNoGallery = false;
 
    protected $mCdnMaxage = 0;
    protected $mCdnMaxageLimit = INF;
 
    protected $mPreventClickjacking = true;
 
    private $mRevisionId = null;
 
    private $mRevisionIsCurrent = null;
 
    private $mRevisionTimestamp = null;
 
    protected $mFileVersion = null;
 
    protected $styles = [];
 
    private $mIndexPolicy = 'index';
    private $mFollowPolicy = 'follow';
 
    private $mRobotsOptions = [ 'max-image-preview' => 'standard' ];
 
    private $mVaryHeader = [
        'Accept-Encoding' => null,
    ];
 
    private $mRedirectedFrom = null;
 
    private $mProperties = [];
 
    private $mTarget = null;
 
    private $mEnableTOC = false;
 
    private $mOutputFlags = [];
 
    private $copyrightUrl;
 
    private $contentLang;
 
    private $limitReportJSData = [];
 
    private $contentOverrides = [];
 
    private $contentOverrideCallbacks = [];
 
    private $mLinkHeader = [];
 
    private $CSP;
 
    private string $cspOutputMode = self::CSP_HEADERS;
 
    private static $cacheVaryCookies = null;
 
    public function __construct( IContextSource $context ) {
        $this->setContext( $context );
        $this->CSP = new ContentSecurityPolicy(
            $context->getRequest()->response(),
            $context->getConfig(),
            $this->getHookContainer()
        );
    }
 
    public function redirect( $url, $responsecode = '302' ) {
        # Strip newlines as a paranoia check for header injection in PHP<5.1.2
        $this->mRedirect = str_replace( "\n", '', $url );
        $this->mRedirectCode = (string)$responsecode;
    }
 
    public function getRedirect() {
        return $this->mRedirect;
    }
 
    public function setCopyrightUrl( $url ) {
        $this->copyrightUrl = $url;
    }
 
    public function setStatusCode( $statusCode ) {
        $this->mStatusCode = $statusCode;
    }
 
    public function addMeta( $name, $val ) {
        $this->mMetatags[] = [ $name, $val ];
    }
 
    public function getMetaTags() {
        return $this->mMetatags;
    }
 
    public function addLink( array $linkarr ) {
        $this->mLinktags[] = $linkarr;
    }
 
    public function getLinkTags() {
        return $this->mLinktags;
    }
 
    public function setCanonicalUrl( $url ) {
        $this->mCanonicalUrl = $url;
    }
 
    public function getCanonicalUrl() {
        return $this->mCanonicalUrl;
    }
 
    public function addScript( $script ) {
        $this->mScripts .= $script;
    }
 
    public function addScriptFile( $file, $unused = null ) {
        $this->addScript( Html::linkedScript( $file ) );
    }
 
    public function addInlineScript( $script ) {
        $this->mScripts .= Html::inlineScript( "\n$script\n" ) . "\n";
    }
 
    protected function filterModules( array $modules, $position = null,
        $type = RL\Module::TYPE_COMBINED
    ) {
        $resourceLoader = $this->getResourceLoader();
        $filteredModules = [];
        foreach ( $modules as $val ) {
            $module = $resourceLoader->getModule( $val );
            if ( $module instanceof RL\Module
                && $module->getOrigin() <= $this->getAllowedModules( $type )
            ) {
                $filteredModules[] = $val;
            }
        }
        return $filteredModules;
    }
 
    public function getModules( $filter = false, $position = null, $param = 'mModules',
        $type = RL\Module::TYPE_COMBINED
    ) {
        $modules = array_values( array_unique( $this->$param ) );
        return $filter
            ? $this->filterModules( $modules, null, $type )
            : $modules;
    }
 
    public function addModules( $modules ) {
        $this->mModules = array_merge( $this->mModules, (array)$modules );
    }
 
    public function getModuleStyles( $filter = false, $position = null ) {
        return $this->getModules( $filter, null, 'mModuleStyles',
            RL\Module::TYPE_STYLES
        );
    }
 
    public function addModuleStyles( $modules ) {
        $this->mModuleStyles = array_merge( $this->mModuleStyles, (array)$modules );
    }
 
    public function getTarget() {
        return $this->mTarget;
    }
 
    public function addContentOverride( $target, Content $content ) {
        if ( !$this->contentOverrides ) {
            // Register a callback for $this->contentOverrides on the first call
            $this->addContentOverrideCallback( function ( $target ) {
                $key = $target->getNamespace() . ':' . $target->getDBkey();
                return $this->contentOverrides[$key] ?? null;
            } );
        }
 
        $key = $target->getNamespace() . ':' . $target->getDBkey();
        $this->contentOverrides[$key] = $content;
    }
 
    public function addContentOverrideCallback( callable $callback ) {
        $this->contentOverrideCallbacks[] = $callback;
    }
 
    public function addHtmlClasses( $classes ) {
        $this->mAdditionalHtmlClasses = array_merge( $this->mAdditionalHtmlClasses, (array)$classes );
    }
 
    public function getHeadItemsArray() {
        return $this->mHeadItems;
    }
 
    public function addHeadItem( $name, $value ) {
        $this->mHeadItems[$name] = $value;
    }
 
    public function addHeadItems( $values ) {
        $this->mHeadItems = array_merge( $this->mHeadItems, (array)$values );
    }
 
    public function hasHeadItem( $name ) {
        return isset( $this->mHeadItems[$name] );
    }
 
    public function addBodyClasses( $classes ) {
        $this->mAdditionalBodyClasses = array_merge( $this->mAdditionalBodyClasses, (array)$classes );
    }
 
    public function setArticleBodyOnly( $only ) {
        $this->mArticleBodyOnly = $only;
    }
 
    public function getArticleBodyOnly() {
        return $this->mArticleBodyOnly;
    }
 
    public function setProperty( $name, $value ) {
        $this->mProperties[$name] = $value;
    }
 
    public function getProperty( $name ) {
        return $this->mProperties[$name] ?? null;
    }
 
    public function checkLastModified( $timestamp ) {
        if ( !$timestamp || $timestamp == '19700101000000' ) {
            wfDebug( __METHOD__ . ': CACHE DISABLED, NO TIMESTAMP' );
            return false;
        }
        $config = $this->getConfig();
        if ( !$config->get( MainConfigNames::CachePages ) ) {
            wfDebug( __METHOD__ . ': CACHE DISABLED' );
            return false;
        }
 
        $timestamp = wfTimestamp( TS_MW, $timestamp );
        $modifiedTimes = [
            'page' => $timestamp,
            'user' => $this->getUser()->getTouched(),
            'epoch' => $config->get( MainConfigNames::CacheEpoch )
        ];
        if ( $config->get( MainConfigNames::UseCdn ) ) {
            $modifiedTimes['sepoch'] = wfTimestamp( TS_MW, $this->getCdnCacheEpoch(
                time(),
                $config->get( MainConfigNames::CdnMaxAge )
            ) );
        }
        $this->getHookRunner()->onOutputPageCheckLastModified( $modifiedTimes, $this );
 
        $maxModified = max( $modifiedTimes );
        $this->mLastModified = wfTimestamp( TS_RFC2822, $maxModified );
 
        $clientHeader = $this->getRequest()->getHeader( 'If-Modified-Since' );
        if ( $clientHeader === false ) {
            wfDebug( __METHOD__ . ': client did not send If-Modified-Since header', 'private' );
            return false;
        }
 
        # IE sends sizes after the date like this:
        # Wed, 20 Aug 2003 06:51:19 GMT; length=5202
        # this breaks strtotime().
        $clientHeader = preg_replace( '/;.*$/', '', $clientHeader );
 
        // E_STRICT system time warnings
        AtEase::suppressWarnings();
        $clientHeaderTime = strtotime( $clientHeader );
        AtEase::restoreWarnings();
        if ( !$clientHeaderTime ) {
            wfDebug( __METHOD__
                . ": unable to parse the client's If-Modified-Since header: $clientHeader" );
            return false;
        }
        $clientHeaderTime = wfTimestamp( TS_MW, $clientHeaderTime );
 
        # Make debug info
        $info = '';
        foreach ( $modifiedTimes as $name => $value ) {
            if ( $info !== '' ) {
                $info .= ', ';
            }
            $info .= "$name=" . wfTimestamp( TS_ISO_8601, $value );
        }
 
        wfDebug( __METHOD__ . ': client sent If-Modified-Since: ' .
            wfTimestamp( TS_ISO_8601, $clientHeaderTime ), 'private' );
        wfDebug( __METHOD__ . ': effective Last-Modified: ' .
            wfTimestamp( TS_ISO_8601, $maxModified ), 'private' );
        if ( $clientHeaderTime < $maxModified ) {
            wfDebug( __METHOD__ . ": STALE, $info", 'private' );
            return false;
        }
 
        # Not modified
        # Give a 304 Not Modified response code and disable body output
        wfDebug( __METHOD__ . ": NOT MODIFIED, $info", 'private' );
        ini_set( 'zlib.output_compression', 0 );
        $this->getRequest()->response()->statusHeader( 304 );
        $this->sendCacheControl();
        $this->disable();
 
        // Don't output a compressed blob when using ob_gzhandler;
        // it's technically against HTTP spec and seems to confuse
        // Firefox when the response gets split over two packets.
        wfResetOutputBuffers( false );
 
        return true;
    }
 
    private function getCdnCacheEpoch( $reqTime, $maxAge ) {
        // Ensure Last-Modified is never more than $wgCdnMaxAge in the past,
        // because even if the wiki page content hasn't changed since, static
        // resources may have changed (skin HTML, interface messages, urls, etc.)
        // and must roll-over in a timely manner (T46570)
        return $reqTime - $maxAge;
    }
 
    public function setLastModified( $timestamp ) {
        $this->mLastModified = wfTimestamp( TS_RFC2822, $timestamp );
    }
 
    public function setRobotPolicy( $policy ) {
        $policy = Article::formatRobotPolicy( $policy );
 
        if ( isset( $policy['index'] ) ) {
            $this->setIndexPolicy( $policy['index'] );
        }
        if ( isset( $policy['follow'] ) ) {
            $this->setFollowPolicy( $policy['follow'] );
        }
    }
 
    public function getRobotPolicy() {
        return "{$this->mIndexPolicy},{$this->mFollowPolicy}";
    }
 
    private function formatRobotsOptions(): string {
        $options = $this->mRobotsOptions;
        // Check if options array has any non-integer keys.
        if ( count( array_filter( array_keys( $options ), 'is_string' ) ) > 0 ) {
            // Robots meta tags can have directives that are single strings or
            // have parameters that should be formatted like <directive>:<setting>.
            // If the options keys are strings, format them accordingly.
            // https://developers.google.com/search/docs/advanced/robots/robots_meta_tag
            array_walk( $options, static function ( &$value, $key ) {
                $value = is_string( $key ) ? "{$key}:{$value}" : "{$value}";
            } );
        }
        return implode( ',', $options );
    }
 
    public function setRobotsOptions( array $options = [] ): void {
        $this->mRobotsOptions = array_merge( $this->mRobotsOptions, $options );
    }
 
    private function getRobotsContent(): string {
        $robotOptionString = $this->formatRobotsOptions();
        $robotArgs = ( $this->mIndexPolicy === 'index' &&
            $this->mFollowPolicy === 'follow' ) ?
            [] :
            [
                $this->mIndexPolicy,
                $this->mFollowPolicy,
            ];
        if ( $robotOptionString ) {
            $robotArgs[] = $robotOptionString;
        }
        return implode( ',', $robotArgs );
    }
 
    public function setIndexPolicy( $policy ) {
        $policy = trim( $policy );
        if ( in_array( $policy, [ 'index', 'noindex' ] ) ) {
            $this->mIndexPolicy = $policy;
        }
    }
 
    public function getIndexPolicy() {
        return $this->mIndexPolicy;
    }
 
    public function setFollowPolicy( $policy ) {
        $policy = trim( $policy );
        if ( in_array( $policy, [ 'follow', 'nofollow' ] ) ) {
            $this->mFollowPolicy = $policy;
        }
    }
 
    public function getFollowPolicy() {
        return $this->mFollowPolicy;
    }
 
    public function setHTMLTitle( $name ) {
        if ( $name instanceof Message ) {
            $this->mHTMLtitle = $name->setContext( $this->getContext() )->text();
        } else {
            $this->mHTMLtitle = $name;
        }
    }
 
    public function getHTMLTitle() {
        return $this->mHTMLtitle;
    }
 
    public function setRedirectedFrom( PageReference $t ) {
        $this->mRedirectedFrom = $t;
    }
 
    public function setPageTitle( $name ) {
        if ( $name instanceof Message ) {
            // T343994: use ::setPageTitleMsg() instead (which uses ::escaped())
            wfDeprecated( __METHOD__ . ' with Message argument', '1.41' );
            $name = $name->setContext( $this->getContext() )->text();
        }
        $this->setPageTitleInternal( $name );
    }
 
    public function setPageTitleMsg( Message $msg ): void {
        $this->setPageTitleInternal(
            $msg->setContext( $this->getContext() )->escaped()
        );
    }
 
    private function setPageTitleInternal( string $name ): void {
        # change "<script>foo&bar</script>" to "&lt;script&gt;foo&amp;bar&lt;/script&gt;"
        # but leave "<i>foobar</i>" alone
        $nameWithTags = Sanitizer::removeSomeTags( $name );
        $this->mPageTitle = $nameWithTags;
 
        # change "<i>foo&amp;bar</i>" to "foo&bar"
        $this->setHTMLTitle(
            $this->msg( 'pagetitle' )->plaintextParams( Sanitizer::stripAllTags( $nameWithTags ) )
                ->inContentLanguage()
        );
    }
 
    public function getPageTitle() {
        return $this->mPageTitle;
    }
 
    public function setDisplayTitle( $html ) {
        $this->displayTitle = $html;
    }
 
    public function getDisplayTitle() {
        $html = $this->displayTitle;
        if ( $html === null ) {
            return htmlspecialchars( $this->getTitle()->getPrefixedText(), ENT_NOQUOTES );
        }
 
        return Sanitizer::removeSomeTags( $html );
    }
 
    public function getUnprefixedDisplayTitle() {
        $service = MediaWikiServices::getInstance();
        $languageConverter = $service->getLanguageConverterFactory()
            ->getLanguageConverter( $service->getContentLanguage() );
        $text = $this->getDisplayTitle();
 
        // Create a regexp with matching groups as placeholders for the namespace, separator and main text
        $pageTitleRegexp = '/^' . str_replace(
            preg_quote( '(.+?)', '/' ),
            '(.+?)',
            preg_quote( Parser::formatPageTitle( '(.+?)', '(.+?)', '(.+?)' ), '/' )
        ) . '$/';
        $matches = [];
        if ( preg_match( $pageTitleRegexp, $text, $matches ) ) {
            // The regexp above could be manipulated by malicious user input,
            // sanitize the result just in case
            return Sanitizer::removeSomeTags( $matches[3] );
        }
 
        $nsPrefix = $languageConverter->convertNamespace(
            $this->getTitle()->getNamespace()
        ) . ':';
        $prefix = preg_quote( $nsPrefix, '/' );
 
        return preg_replace( "/^$prefix/i", '', $text );
    }
 
    public function setTitle( PageReference $t ) {
        $t = Title::newFromPageReference( $t );
 
        // @phan-suppress-next-next-line PhanUndeclaredMethod
        // @fixme Not all implementations of IContextSource have this method!
        $this->getContext()->setTitle( $t );
    }
 
    public function setSubtitle( $str ) {
        $this->clearSubtitle();
        $this->addSubtitle( $str );
    }
 
    public function addSubtitle( $str ) {
        if ( $str instanceof Message ) {
            $this->mSubtitle[] = $str->setContext( $this->getContext() )->parse();
        } else {
            $this->mSubtitle[] = $str;
        }
    }
 
    public static function buildBacklinkSubtitle( PageReference $page, $query = [] ) {
        if ( $page instanceof PageRecord || $page instanceof Title ) {
            // Callers will typically have a PageRecord
            if ( $page->isRedirect() ) {
                $query['redirect'] = 'no';
            }
        } elseif ( $page->getNamespace() !== NS_SPECIAL ) {
            // We don't know whether it's a redirect, so add the parameter, just to be sure.
            $query['redirect'] = 'no';
        }
 
        $linkRenderer = MediaWikiServices::getInstance()->getLinkRenderer();
        return wfMessage( 'backlinksubtitle' )
            ->rawParams( $linkRenderer->makeLink( $page, null, [], $query ) );
    }
 
    public function addBacklinkSubtitle( PageReference $title, $query = [] ) {
        $this->addSubtitle( self::buildBacklinkSubtitle( $title, $query ) );
    }
 
    public function clearSubtitle() {
        $this->mSubtitle = [];
    }
 
    public function getSubtitle() {
        return implode( "<br />\n\t\t\t\t", $this->mSubtitle );
    }
 
    public function setPrintable() {
        $this->mPrintable = true;
    }
 
    public function isPrintable() {
        return $this->mPrintable;
    }
 
    public function disable() {
        $this->mDoNothing = true;
    }
 
    public function isDisabled() {
        return $this->mDoNothing;
    }
 
    public function showNewSectionLink() {
        return $this->mNewSectionLink;
    }
 
    public function forceHideNewSectionLink() {
        return $this->mHideNewSectionLink;
    }
 
    public function setSyndicated( $show = true ) {
        if ( $show ) {
            $this->setFeedAppendQuery( false );
        } else {
            $this->mFeedLinks = [];
        }
    }
 
    protected function getAdvertisedFeedTypes() {
        if ( $this->getConfig()->get( MainConfigNames::Feed ) ) {
            return $this->getConfig()->get( MainConfigNames::AdvertisedFeedTypes );
        } else {
            return [];
        }
    }
 
    public function setFeedAppendQuery( $val ) {
        $this->mFeedLinks = [];
 
        foreach ( $this->getAdvertisedFeedTypes() as $type ) {
            $query = "feed=$type";
            if ( is_string( $val ) ) {
                $query .= '&' . $val;
            }
            $this->mFeedLinks[$type] = $this->getTitle()->getLocalURL( $query );
        }
    }
 
    public function addFeedLink( $format, $href ) {
        if ( in_array( $format, $this->getAdvertisedFeedTypes() ) ) {
            $this->mFeedLinks[$format] = $href;
        }
    }
 
    public function isSyndicated() {
        return count( $this->mFeedLinks ) > 0;
    }
 
    public function getSyndicationLinks() {
        return $this->mFeedLinks;
    }
 
    public function getFeedAppendQuery() {
        return $this->mFeedLinksAppendQuery;
    }
 
    public function setArticleFlag( $newVal ) {
        $this->mIsArticle = $newVal;
        if ( $newVal ) {
            $this->mIsArticleRelated = $newVal;
        }
    }
 
    public function isArticle() {
        return $this->mIsArticle;
    }
 
    public function setArticleRelated( $newVal ) {
        $this->mIsArticleRelated = $newVal;
        if ( !$newVal ) {
            $this->mIsArticle = false;
        }
    }
 
    public function isArticleRelated() {
        return $this->mIsArticleRelated;
    }
 
    public function setCopyright( $hasCopyright ) {
        $this->mHasCopyright = $hasCopyright;
    }
 
    public function showsCopyright() {
        return $this->isArticle() || $this->mHasCopyright;
    }
 
    public function addLanguageLinks( array $newLinkArray ) {
        $this->mLanguageLinks = array_merge( $this->mLanguageLinks, $newLinkArray );
    }
 
    public function setLanguageLinks( array $newLinkArray ) {
        $this->mLanguageLinks = $newLinkArray;
    }
 
    public function getLanguageLinks() {
        return $this->mLanguageLinks;
    }
 
    public function addCategoryLinks( array $categories ) {
        if ( !$categories ) {
            return;
        }
 
        $res = $this->addCategoryLinksToLBAndGetResult( $categories );
 
        # Set all the values to 'normal'.
        $categories = array_fill_keys( array_keys( $categories ), 'normal' );
        $pageData = [];
 
        # Mark hidden categories
        foreach ( $res as $row ) {
            if ( isset( $row->pp_value ) ) {
                $categories[$row->page_title] = 'hidden';
            }
            // Page exists, cache results
            if ( isset( $row->page_id ) ) {
                $pageData[$row->page_title] = $row;
            }
        }
 
        # Add the remaining categories to the skin
        if ( $this->getHookRunner()->onOutputPageMakeCategoryLinks(
            $this, $categories, $this->mCategoryLinks )
        ) {
            $services = MediaWikiServices::getInstance();
            $linkRenderer = $services->getLinkRenderer();
            $languageConverter = $services->getLanguageConverterFactory()
                ->getLanguageConverter( $services->getContentLanguage() );
            foreach ( $categories as $category => $type ) {
                // array keys will cast numeric category names to ints, so cast back to string
                $category = (string)$category;
                $origcategory = $category;
                if ( array_key_exists( $category, $pageData ) ) {
                    $title = Title::newFromRow( $pageData[$category] );
                } else {
                    $title = Title::makeTitleSafe( NS_CATEGORY, $category );
                }
                if ( !$title ) {
                    continue;
                }
                $languageConverter->findVariantLink( $category, $title, true );
 
                if ( $category != $origcategory && array_key_exists( $category, $categories ) ) {
                    continue;
                }
                $text = $languageConverter->convertHtml( $title->getText() );
                $this->mCategories[$type][] = $title->getText();
                $this->mCategoryLinks[$type][] = $linkRenderer->makeLink( $title, new HtmlArmor( $text ) );
            }
        }
    }
 
    protected function addCategoryLinksToLBAndGetResult( array $categories ) {
        # Add the links to a LinkBatch
        $arr = [ NS_CATEGORY => $categories ];
        $linkBatchFactory = MediaWikiServices::getInstance()->getLinkBatchFactory();
        $lb = $linkBatchFactory->newLinkBatch();
        $lb->setArray( $arr );
 
        # Fetch existence plus the hiddencat property
        $dbr = MediaWikiServices::getInstance()->getConnectionProvider()->getReplicaDatabase();
        $fields = array_merge(
            LinkCache::getSelectFields(),
            [ 'pp_value' ]
        );
 
        $res = $dbr->newSelectQueryBuilder()
            ->select( $fields )
            ->from( 'page' )
            ->leftJoin( 'page_props', null, [
                'pp_propname' => 'hiddencat',
                'pp_page = page_id',
            ] )
            ->where( $lb->constructSet( 'page', $dbr ) )
            ->caller( __METHOD__ )
            ->fetchResultSet();
 
        # Add the results to the link cache
        $linkCache = MediaWikiServices::getInstance()->getLinkCache();
        $lb->addResultToCache( $linkCache, $res );
 
        return $res;
    }
 
    public function setCategoryLinks( array $categories ) {
        $this->mCategoryLinks = [];
        $this->addCategoryLinks( $categories );
    }
 
    public function getCategoryLinks() {
        return $this->mCategoryLinks;
    }
 
    public function getCategories( $type = 'all' ) {
        if ( $type === 'all' ) {
            $allCategories = [];
            foreach ( $this->mCategories as $categories ) {
                $allCategories = array_merge( $allCategories, $categories );
            }
            return $allCategories;
        }
        if ( !isset( $this->mCategories[$type] ) ) {
            throw new InvalidArgumentException( 'Invalid category type given: ' . $type );
        }
        return $this->mCategories[$type];
    }
 
    public function setIndicators( array $indicators ) {
        $this->mIndicators = $indicators + $this->mIndicators;
        // Keep ordered by key
        ksort( $this->mIndicators );
    }
 
    public function getIndicators(): array {
        // Note that some -- but not all -- indicators will be wrapped
        // with a class appropriate for user-generated wikitext content
        // (usually .mw-parser-output). The exceptions would be an
        // indicator added via ::addHelpLink() below, which adds content
        // which don't come from the parser and is not user-generated;
        // and any indicators added by extensions which may call
        // OutputPage::setIndicators() directly.  In the latter case the
        // caller is responsible for wrapping any parser-generated
        // indicators.
        return $this->mIndicators;
    }
 
    public function addHelpLink( $to, $overrideBaseUrl = false ) {
        $this->addModuleStyles( 'mediawiki.helplink' );
        $text = $this->msg( 'helppage-top-gethelp' )->escaped();
 
        if ( $overrideBaseUrl ) {
            $helpUrl = $to;
        } else {
            $toUrlencoded = wfUrlencode( str_replace( ' ', '_', $to ) );
            $helpUrl = "https://www.mediawiki.org/wiki/Special:MyLanguage/$toUrlencoded";
        }
 
        $link = Html::rawElement(
            'a',
            [
                'href' => $helpUrl,
                'target' => '_blank',
                'class' => 'mw-helplink',
            ],
            Html::element( 'span', [ 'class' => 'mw-helplink-icon' ] ) . $text
        );
 
        // See note in ::getIndicators() above -- unlike wikitext-generated
        // indicators which come from ParserOutput, this indicator will not
        // be wrapped.
        $this->setIndicators( [ 'mw-helplink' => $link ] );
    }
 
    public function disallowUserJs() {
        $this->reduceAllowedModules(
            RL\Module::TYPE_SCRIPTS,
            RL\Module::ORIGIN_CORE_INDIVIDUAL
        );
 
        // Site-wide styles are controlled by a config setting, see T73621
        // for background on why. User styles are never allowed.
        if ( $this->getConfig()->get( MainConfigNames::AllowSiteCSSOnRestrictedPages ) ) {
            $styleOrigin = RL\Module::ORIGIN_USER_SITEWIDE;
        } else {
            $styleOrigin = RL\Module::ORIGIN_CORE_INDIVIDUAL;
        }
        $this->reduceAllowedModules(
            RL\Module::TYPE_STYLES,
            $styleOrigin
        );
    }
 
    public function getAllowedModules( $type ) {
        if ( $type == RL\Module::TYPE_COMBINED ) {
            return min( array_values( $this->mAllowedModules ) );
        } else {
            return $this->mAllowedModules[$type] ?? RL\Module::ORIGIN_ALL;
        }
    }
 
    public function reduceAllowedModules( $type, $level ) {
        $this->mAllowedModules[$type] = min( $this->getAllowedModules( $type ), $level );
    }
 
    public function prependHTML( $text ) {
        $this->mBodytext = $text . $this->mBodytext;
    }
 
    public function addHTML( $text ) {
        $this->mBodytext .= $text;
    }
 
    public function addElement( $element, array $attribs = [], $contents = '' ) {
        $this->addHTML( Html::element( $element, $attribs, $contents ) );
    }
 
    public function clearHTML() {
        $this->mBodytext = '';
    }
 
    public function getHTML() {
        return $this->mBodytext;
    }
 
    public function parserOptions() {
        if ( !$this->mParserOptions ) {
            if ( !$this->getUser()->isSafeToLoad() ) {
                // Context user isn't unstubbable yet, so don't try to get a
                // ParserOptions for it. And don't cache this ParserOptions
                // either.
                $po = ParserOptions::newFromAnon();
                $po->setAllowUnsafeRawHtml( false );
                return $po;
            }
 
            $this->mParserOptions = ParserOptions::newFromContext( $this->getContext() );
            $this->mParserOptions->setAllowUnsafeRawHtml( false );
        }
 
        return $this->mParserOptions;
    }
 
    public function setRevisionId( $revid ) {
        $val = $revid === null ? null : intval( $revid );
        return wfSetVar( $this->mRevisionId, $val, true );
    }
 
    public function getRevisionId() {
        return $this->mRevisionId;
    }
 
    public function setRevisionIsCurrent( bool $isCurrent ): void {
        $this->mRevisionIsCurrent = $isCurrent;
    }
 
    public function isRevisionCurrent(): bool {
        return $this->mRevisionId == 0 || (
            $this->mRevisionIsCurrent ?? (
                $this->mRevisionId == $this->getTitle()->getLatestRevID()
            )
        );
    }
 
    public function setRevisionTimestamp( $timestamp ) {
        return wfSetVar( $this->mRevisionTimestamp, $timestamp, true );
    }
 
    public function getRevisionTimestamp() {
        return $this->mRevisionTimestamp;
    }
 
    public function setFileVersion( $file ) {
        $val = null;
        if ( $file instanceof File && $file->exists() ) {
            $val = [ 'time' => $file->getTimestamp(), 'sha1' => $file->getSha1() ];
        }
        return wfSetVar( $this->mFileVersion, $val, true );
    }
 
    public function getFileVersion() {
        return $this->mFileVersion;
    }
 
    public function getTemplateIds() {
        return $this->mTemplateIds;
    }
 
    public function getFileSearchOptions() {
        return $this->mImageTimeKeys;
    }
 
    public function addWikiTextAsInterface(
        $text, $linestart = true, PageReference $title = null
    ) {
        $title ??= $this->getTitle();
        if ( $title === null ) {
            throw new RuntimeException( 'No title in ' . __METHOD__ );
        }
        $this->addWikiTextTitleInternal( $text, $title, $linestart, /*interface*/true );
    }
 
    public function wrapWikiTextAsInterface(
        $wrapperClass, $text
    ) {
        $title = $this->getTitle();
        if ( $title === null ) {
            throw new RuntimeException( 'No title in ' . __METHOD__ );
        }
        $this->addWikiTextTitleInternal(
            $text, $title,
            /*linestart*/true, /*interface*/true,
            $wrapperClass
        );
    }
 
    public function addWikiTextAsContent(
        $text, $linestart = true, PageReference $title = null
    ) {
        $title ??= $this->getTitle();
        if ( !$title ) {
            throw new RuntimeException( 'No title in ' . __METHOD__ );
        }
        $this->addWikiTextTitleInternal( $text, $title, $linestart, /*interface*/false );
    }
 
    private function addWikiTextTitleInternal(
        string $text, PageReference $title, bool $linestart, bool $interface,
        ?string $wrapperClass = null
    ) {
        $parserOutput = $this->parseInternal(
            $text, $title, $linestart, $interface
        );
 
        $this->addParserOutput( $parserOutput, [
            'enableSectionEditLinks' => false,
            'wrapperDivClass' => $wrapperClass ?? '',
        ] );
    }
 
    public function setTOCData( TOCData $tocData ) {
        $this->tocData = $tocData;
    }
 
    public function getTOCData(): ?TOCData {
        return $this->tocData;
    }
 
    public function getOutputFlag( string $name ): bool {
        return isset( $this->mOutputFlags[$name] );
    }
 
    public function setContentLangForJS( Bcp47Code $lang ): void {
        $this->contentLang = MediaWikiServices::getInstance()->getLanguageFactory()
            ->getLanguage( $lang );
    }
 
    private function getContentLangForJS(): Language {
        if ( !$this->contentLang ) {
            // If this is not set, then we're likely not on in a request that renders page content
            // (e.g. ViewAction or ApiParse), but rather a different Action or SpecialPage.
            // In that case there isn't a main ParserOutput object to represent the page or output.
            // But, the skin and frontend code mostly don't make this distinction, and so we still
            // need to return something for mw.config.
            //
            // For historical reasons, the expectation is that:
            // * on a SpecialPage, we return the language for the content area just like on a
            //   page view. SpecialPage content is localised, and so this is the user language.
            // * on an Action about a WikiPage, we return the language that content would have
            //   been shown in, if this were a page view. This is generally the page language
            //   as stored in the database, except adapted to the current user (e.g. in case of
            //   translated pages or a language variant preference)
            //
            // This mess was centralised to here in 2023 (T341244).
            $title = $this->getTitle();
            if ( $title->isSpecialPage() ) {
                // Special pages render in the interface language, based on request context.
                // If the user's preference (or request parameter) specifies a variant,
                // the content may have been converted to the user's language variant.
                $pageLang = $this->getLanguage();
            } else {
                wfDebug( __METHOD__ . ' has to guess ParserOutput language' );
                // Guess what Article::getParserOutput and ParserOptions::optionsHash() would decide
                // on a page view:
                //
                // - Pages may have a custom page_lang set in the database,
                //   via Title::getPageLanguage/Title::getDbPageLanguage
                //
                // - Interface messages (NS_MEDIAWIKI) render based on their subpage,
                //   via Title::getPageLanguage/ContentHandler::getPageLanguage/MessageCache::figureMessage
                //
                // - Otherwise, pages are assumed to be in the wiki's default content language.
                //   via Title::getPageLanguage/ContentHandler::getPageLanguage/MediaWikiServices::getContentLanguage
                $pageLang = $title->getPageLanguage();
            }
            if ( $title->getNamespace() !== NS_MEDIAWIKI ) {
                $services = MediaWikiServices::getInstance();
                $langConv = $services->getLanguageConverterFactory()->getLanguageConverter( $pageLang );
                // NOTE: LanguageConverter::getPreferredVariant inspects global RequestContext.
                // This usually returns $pageLang unchanged.
                $variant = $langConv->getPreferredVariant();
                if ( $pageLang->getCode() !== $variant ) {
                    $pageLang = $services->getLanguageFactory()->getLanguage( $variant );
                }
            }
            $this->contentLang = $pageLang;
        }
        return $this->contentLang;
    }
 
    public function addParserOutputMetadata( ParserOutput $parserOutput ) {
        // T301020 This should eventually use the standard "merge ParserOutput"
        // function between $parserOutput and $this->metadata.
        $this->mLanguageLinks =
            array_merge( $this->mLanguageLinks, $parserOutput->getLanguageLinks() );
        $this->addCategoryLinks( $parserOutput->getCategoryMap() );
 
        // Parser-generated indicators get wrapped like other parser output.
        $wrapClass = $parserOutput->getWrapperDivClass();
        $result = [];
        foreach ( $parserOutput->getIndicators() as $name => $html ) {
            if ( $html !== '' && $wrapClass !== '' ) {
                $html = Html::rawElement( 'div', [ 'class' => $wrapClass ], $html );
            }
            $result[$name] = $html;
        }
        $this->setIndicators( $result );
 
        $tocData = $parserOutput->getTOCData();
        // Do not override existing TOC data if the new one is empty (T307256#8817705)
        // TODO: Invent a way to merge TOCs from multiple outputs (T327429)
        if ( $tocData !== null && ( $this->tocData === null || count( $tocData->getSections() ) > 0 ) ) {
            $this->setTOCData( $tocData );
        }
 
        // FIXME: Best practice is for OutputPage to be an accumulator, as
        // addParserOutputMetadata() may be called multiple times, but the
        // following lines overwrite any previous data.  These should
        // be migrated to an injection pattern. (T301020, T300979)
        // (Note that OutputPage::getOutputFlag() also contains this
        // information, with flags from each $parserOutput all OR'ed together.)
        $this->mNewSectionLink = $parserOutput->getNewSection();
        $this->mHideNewSectionLink = $parserOutput->getHideNewSection();
        $this->mNoGallery = $parserOutput->getNoGallery();
 
        if ( !$parserOutput->isCacheable() ) {
            $this->disableClientCache();
        }
        $this->addHeadItems( $parserOutput->getHeadItems() );
        $this->addModules( $parserOutput->getModules() );
        $this->addModuleStyles( $parserOutput->getModuleStyles() );
        $this->addJsConfigVars( $parserOutput->getJsConfigVars() );
        $this->mPreventClickjacking = $this->mPreventClickjacking
            || $parserOutput->getPreventClickjacking();
        $scriptSrcs = $parserOutput->getExtraCSPScriptSrcs();
        foreach ( $scriptSrcs as $src ) {
            $this->getCSP()->addScriptSrc( $src );
        }
        $defaultSrcs = $parserOutput->getExtraCSPDefaultSrcs();
        foreach ( $defaultSrcs as $src ) {
            $this->getCSP()->addDefaultSrc( $src );
        }
        $styleSrcs = $parserOutput->getExtraCSPStyleSrcs();
        foreach ( $styleSrcs as $src ) {
            $this->getCSP()->addStyleSrc( $src );
        }
 
        // If $wgImagePreconnect is true, and if the output contains images, give the user-agent
        // a hint about a remote hosts from which images may be served. Launched in T123582.
        if ( $this->getConfig()->get( MainConfigNames::ImagePreconnect ) && count( $parserOutput->getImages() ) ) {
            $preconnect = [];
            // Optimization: Instead of processing each image, assume that wikis either serve both
            // foreign and local from the same remote hostname (e.g. public wikis at WMF), or that
            // foreign images are common enough to be worth the preconnect (e.g. private wikis).
            $repoGroup = MediaWikiServices::getInstance()->getRepoGroup();
            $repoGroup->forEachForeignRepo( static function ( $repo ) use ( &$preconnect ) {
                $preconnect[] = $repo->getZoneUrl( 'thumb' );
            } );
            // Consider both foreign and local repos. While LocalRepo by default uses a relative
            // path on the same domain, wiki farms may configure it to use a dedicated hostname.
            $preconnect[] = $repoGroup->getLocalRepo()->getZoneUrl( 'thumb' );
            foreach ( $preconnect as $url ) {
                $host = parse_url( $url, PHP_URL_HOST );
                // It is expected that file URLs are often path-only, without hostname (T317329).
                if ( $host ) {
                    $this->addLink( [ 'rel' => 'preconnect', 'href' => '//' . $host ] );
                    break;
                }
            }
        }
 
        // Template versioning...
        foreach ( (array)$parserOutput->getTemplateIds() as $ns => $dbks ) {
            if ( isset( $this->mTemplateIds[$ns] ) ) {
                $this->mTemplateIds[$ns] = $dbks + $this->mTemplateIds[$ns];
            } else {
                $this->mTemplateIds[$ns] = $dbks;
            }
        }
        // File versioning...
        foreach ( (array)$parserOutput->getFileSearchOptions() as $dbk => $data ) {
            $this->mImageTimeKeys[$dbk] = $data;
        }
 
        // Enable OOUI if requested via ParserOutput
        if ( $parserOutput->getEnableOOUI() ) {
            $this->enableOOUI();
        }
 
        // Include parser limit report
        // FIXME: This should append, rather than overwrite, or else this
        // data should be injected into the OutputPage like is done for the
        // other page-level things (like OutputPage::setTOCData()).
        if ( !$this->limitReportJSData ) {
            $this->limitReportJSData = $parserOutput->getLimitReportJSData();
        }
 
        // Link flags are ignored for now, but may in the future be
        // used to mark individual language links.
        $linkFlags = [];
        $this->getHookRunner()->onLanguageLinks( $this->getTitle(), $this->mLanguageLinks, $linkFlags );
 
        $this->getHookRunner()->onOutputPageParserOutput( $this, $parserOutput );
 
        // This check must be after 'OutputPageParserOutput' runs in addParserOutputMetadata
        // so that extensions may modify ParserOutput to toggle TOC.
        // This cannot be moved to addParserOutputText because that is not
        // called by EditPage for Preview.
 
        // ParserOutputFlags::SHOW_TOC is used to indicate whether the TOC
        // should be shown (or hidden) in the output.
        $this->mEnableTOC = $this->mEnableTOC ||
            $parserOutput->getOutputFlag( ParserOutputFlags::SHOW_TOC );
        // Uniform handling of all boolean flags: they are OR'ed together
        // (See ParserOutput::collectMetadata())
        $flags =
            array_flip( $parserOutput->getAllFlags() ) +
            array_flip( ParserOutputFlags::cases() );
        foreach ( $flags as $name => $ignore ) {
            if ( $parserOutput->getOutputFlag( $name ) ) {
                $this->mOutputFlags[$name] = true;
            }
        }
    }
 
    private function getParserOutputText( ParserOutput $parserOutput, array $poOptions = [] ): string {
        // Add default options from the skin
        $skin = $this->getSkin();
        $skinOptions = $skin->getOptions();
        $poOptions += [
            'skin' => $skin,
            'injectTOC' => $skinOptions['toc'],
        ];
        // Note: this path absolutely expects $parserOutput to be mutated by getText, see T353257
        return $parserOutput->getText( $poOptions );
    }
 
    public function addParserOutputContent( ParserOutput $parserOutput, $poOptions = [] ) {
        $text = $this->getParserOutputText( $parserOutput, $poOptions );
        $this->addParserOutputText( $text, $poOptions );
 
        $this->addModules( $parserOutput->getModules() );
        $this->addModuleStyles( $parserOutput->getModuleStyles() );
 
        $this->addJsConfigVars( $parserOutput->getJsConfigVars() );
    }
 
    public function addParserOutputText( $text, $poOptions = [] ) {
        if ( $text instanceof ParserOutput ) {
            wfDeprecated( __METHOD__ . ' with ParserOutput as first arg', '1.42' );
            $text = $this->getParserOutputText( $text, $poOptions );
        }
        $this->getHookRunner()->onOutputPageBeforeHTML( $this, $text );
        $this->addHTML( $text );
    }
 
    public function addParserOutput( ParserOutput $parserOutput, $poOptions = [] ) {
        $text = $this->getParserOutputText( $parserOutput, $poOptions );
        $this->addParserOutputMetadata( $parserOutput );
        $this->addParserOutputText( $text, $poOptions );
    }
 
    public function addTemplate( &$template ) {
        $this->addHTML( $template->getHTML() );
    }
 
    public function parseAsContent( $text, $linestart = true ) {
        $title = $this->getTitle();
        if ( $title === null ) {
            throw new RuntimeException( 'No title in ' . __METHOD__ );
        }
        return $this->parseInternal(
            $text, $title, $linestart, /*interface*/false
        )->getText( [
            'allowTOC' => false,
            'enableSectionEditLinks' => false,
            'wrapperDivClass' => '',
            'userLang' => $this->getContext()->getLanguage(),
        ] );
    }
 
    public function parseAsInterface( $text, $linestart = true ) {
        $title = $this->getTitle();
        if ( $title === null ) {
            throw new RuntimeException( 'No title in ' . __METHOD__ );
        }
        return $this->parseInternal(
            $text, $title, $linestart, /*interface*/true
        )->getText( [
            'allowTOC' => false,
            'enableSectionEditLinks' => false,
            'wrapperDivClass' => '',
            'userLang' => $this->getContext()->getLanguage(),
        ] );
    }
 
    public function parseInlineAsInterface( $text, $linestart = true ) {
        return Parser::stripOuterParagraph(
            $this->parseAsInterface( $text, $linestart )
        );
    }
 
    private function parseInternal(
        string $text, PageReference $title, bool $linestart, bool $interface
    ) {
        $popts = $this->parserOptions();
 
        $oldInterface = $popts->setInterfaceMessage( $interface );
 
        $parserOutput = MediaWikiServices::getInstance()->getParserFactory()->getInstance()
            ->parse(
                $text, $title, $popts,
                $linestart, true, $this->mRevisionId
            );
 
        $popts->setInterfaceMessage( $oldInterface );
 
        return $parserOutput;
    }
 
    public function setCdnMaxage( $maxage ) {
        $this->mCdnMaxage = min( $maxage, $this->mCdnMaxageLimit );
    }
 
    public function lowerCdnMaxage( $maxage ) {
        $this->mCdnMaxageLimit = min( $maxage, $this->mCdnMaxageLimit );
        $this->setCdnMaxage( $this->mCdnMaxage );
    }
 
    public function adaptCdnTTL( $mtime, $minTTL = 0, $maxTTL = 0 ) {
        $minTTL = $minTTL ?: ExpirationAwareness::TTL_MINUTE;
        $maxTTL = $maxTTL ?: $this->getConfig()->get( MainConfigNames::CdnMaxAge );
 
        if ( $mtime === null || $mtime === false ) {
            return; // entity does not exist
        }
 
        $age = MWTimestamp::time() - (int)wfTimestamp( TS_UNIX, $mtime );
        $adaptiveTTL = max( 0.9 * $age, $minTTL );
        $adaptiveTTL = min( $adaptiveTTL, $maxTTL );
 
        $this->lowerCdnMaxage( (int)$adaptiveTTL );
    }
 
    public function enableClientCache(): void {
        $this->mEnableClientCache = true;
    }
 
    public function disableClientCache(): void {
        $this->mEnableClientCache = false;
    }
 
    public function couldBePublicCached() {
        if ( !$this->cacheIsFinal ) {
            // - The entry point handles its own caching and/or doesn't use OutputPage.
            //   (such as load.php, or MediaWiki\Rest\EntryPoint).
            //
            // - Or, we haven't finished processing the main part of the request yet
            //   (e.g. Action::show, SpecialPage::execute), and the state may still
            //   change via enableClientCache().
            return true;
        }
        // e.g. various error-type pages disable all client caching
        return $this->mEnableClientCache;
    }
 
    public function considerCacheSettingsFinal() {
        $this->cacheIsFinal = true;
    }
 
    public function getCacheVaryCookies() {
        if ( self::$cacheVaryCookies === null ) {
            $config = $this->getConfig();
            self::$cacheVaryCookies = array_values( array_unique( array_merge(
                SessionManager::singleton()->getVaryCookies(),
                [
                    'forceHTTPS',
                ],
                $config->get( MainConfigNames::CacheVaryCookies )
            ) ) );
            $this->getHookRunner()->onGetCacheVaryCookies( $this, self::$cacheVaryCookies );
        }
        return self::$cacheVaryCookies;
    }
 
    public function haveCacheVaryCookies() {
        $request = $this->getRequest();
        foreach ( $this->getCacheVaryCookies() as $cookieName ) {
            if ( $request->getCookie( $cookieName, '', '' ) !== '' ) {
                wfDebug( __METHOD__ . ": found $cookieName" );
                return true;
            }
        }
        wfDebug( __METHOD__ . ': no cache-varying cookies found' );
        return false;
    }
 
    public function addVaryHeader( $header ) {
        if ( !array_key_exists( $header, $this->mVaryHeader ) ) {
            $this->mVaryHeader[$header] = null;
        }
    }
 
    public function getVaryHeader() {
        // If we vary on cookies, let's make sure it's always included here too.
        if ( $this->getCacheVaryCookies() ) {
            $this->addVaryHeader( 'Cookie' );
        }
 
        foreach ( SessionManager::singleton()->getVaryHeaders() as $header => $_ ) {
            $this->addVaryHeader( $header );
        }
        return 'Vary: ' . implode( ', ', array_keys( $this->mVaryHeader ) );
    }
 
    public function addLinkHeader( $header ) {
        $this->mLinkHeader[] = $header;
    }
 
    public function getLinkHeader() {
        if ( !$this->mLinkHeader ) {
            return false;
        }
 
        return 'Link: ' . implode( ',', $this->mLinkHeader );
    }
 
    private function addAcceptLanguage() {
        $title = $this->getTitle();
        if ( !$title instanceof Title ) {
            return;
        }
 
        $languageConverter = MediaWikiServices::getInstance()->getLanguageConverterFactory()
            ->getLanguageConverter( $title->getPageLanguage() );
        if ( !$this->getRequest()->getCheck( 'variant' ) && $languageConverter->hasVariants() ) {
            $this->addVaryHeader( 'Accept-Language' );
        }
    }
 
    public function setPreventClickjacking( bool $enable ) {
        $this->mPreventClickjacking = $enable;
    }
 
    public function getPreventClickjacking() {
        return $this->mPreventClickjacking;
    }
 
    public function getFrameOptions() {
        $config = $this->getConfig();
        if ( $config->get( MainConfigNames::BreakFrames ) ) {
            return 'DENY';
        } elseif ( $this->mPreventClickjacking && $config->get( MainConfigNames::EditPageFrameOptions ) ) {
            return $config->get( MainConfigNames::EditPageFrameOptions );
        }
        return false;
    }
 
    private function getReportTo() {
        $config = $this->getConfig();
 
        $expiry = $config->get( MainConfigNames::ReportToExpiry );
 
        if ( !$expiry ) {
            return false;
        }
 
        $endpoints = $config->get( MainConfigNames::ReportToEndpoints );
 
        if ( !$endpoints ) {
            return false;
        }
 
        $output = [ 'max_age' => $expiry, 'endpoints' => [] ];
 
        foreach ( $endpoints as $endpoint ) {
            $output['endpoints'][] = [ 'url' => $endpoint ];
        }
 
        return json_encode( $output, JSON_UNESCAPED_SLASHES );
    }
 
    private function getFeaturePolicyReportOnly() {
        $config = $this->getConfig();
 
        $features = $config->get( MainConfigNames::FeaturePolicyReportOnly );
        return implode( ';', $features );
    }
 
    public function sendCacheControl() {
        $response = $this->getRequest()->response();
        $config = $this->getConfig();
 
        $this->addVaryHeader( 'Cookie' );
        $this->addAcceptLanguage();
 
        # don't serve compressed data to clients who can't handle it
        # maintain different caches for logged-in users and non-logged in ones
        $response->header( $this->getVaryHeader() );
 
        if ( $this->mEnableClientCache ) {
            if ( !$config->get( MainConfigNames::UseCdn ) ) {
                $privateReason = 'config';
            } elseif ( $response->hasCookies() ) {
                $privateReason = 'set-cookies';
            // The client might use methods other than cookies to appear logged-in.
            // E.g. HTTP headers, or query parameter tokens, OAuth, etc.
            } elseif ( SessionManager::getGlobalSession()->isPersistent() ) {
                $privateReason = 'session';
            } elseif ( $this->isPrintable() ) {
                $privateReason = 'printable';
            } elseif ( $this->mCdnMaxage == 0 ) {
                $privateReason = 'no-maxage';
            } elseif ( $this->haveCacheVaryCookies() ) {
                $privateReason = 'cache-vary-cookies';
            } else {
                $privateReason = false;
            }
 
            if ( $privateReason === false ) {
                # We'll purge the proxy cache for anons explicitly, but require end user agents
                # to revalidate against the proxy on each visit.
                # IMPORTANT! The CDN needs to replace the Cache-Control header with
                # Cache-Control: s-maxage=0, must-revalidate, max-age=0
                wfDebug( __METHOD__ .
                    ": local proxy caching; {$this->mLastModified} **", 'private' );
                # start with a shorter timeout for initial testing
                # header( "Cache-Control: s-maxage=2678400, must-revalidate, max-age=0" );
                $response->header( 'Cache-Control: ' .
                    "s-maxage={$this->mCdnMaxage}, must-revalidate, max-age=0" );
            } else {
                # We do want clients to cache if they can, but they *must* check for updates
                # on revisiting the page.
                wfDebug( __METHOD__ . ": private caching ($privateReason); {$this->mLastModified} **", 'private' );
 
                $response->header( 'Expires: ' . gmdate( 'D, d M Y H:i:s', 0 ) . ' GMT' );
                $response->header( 'Cache-Control: private, must-revalidate, max-age=0' );
            }
            if ( $this->mLastModified ) {
                $response->header( "Last-Modified: {$this->mLastModified}" );
            }
        } else {
            wfDebug( __METHOD__ . ': no caching **', 'private' );
 
            # In general, the absence of a last modified header should be enough to prevent
            # the client from using its cache. We send a few other things just to make sure.
            $response->header( 'Expires: ' . gmdate( 'D, d M Y H:i:s', 0 ) . ' GMT' );
            $response->header( 'Cache-Control: no-cache, no-store, max-age=0, must-revalidate' );
        }
    }
 
    public function loadSkinModules( $sk ) {
        foreach ( $sk->getDefaultModules() as $group => $modules ) {
            if ( $group === 'styles' ) {
                foreach ( $modules as $moduleMembers ) {
                    $this->addModuleStyles( $moduleMembers );
                }
            } else {
                $this->addModules( $modules );
            }
        }
    }
 
    public function output( $return = false ) {
        if ( $this->mDoNothing ) {
            return $return ? '' : null;
        }
 
        $request = $this->getRequest();
        $response = $request->response();
        $config = $this->getConfig();
 
        if ( $this->mRedirect != '' ) {
            $services = MediaWikiServices::getInstance();
            // Modern standards don't require redirect URLs to be absolute, but make it so just in case.
            // Note that this doesn't actually guarantee an absolute URL: relative-path URLs are left intact.
            $this->mRedirect = (string)$services->getUrlUtils()->expand( $this->mRedirect, PROTO_CURRENT );
 
            $redirect = $this->mRedirect;
            $code = $this->mRedirectCode;
            $content = '';
 
            if ( $this->getHookRunner()->onBeforePageRedirect( $this, $redirect, $code ) ) {
                if ( $code == '301' || $code == '303' ) {
                    if ( !$config->get( MainConfigNames::DebugRedirects ) ) {
                        $response->statusHeader( (int)$code );
                    }
                    $this->mLastModified = wfTimestamp( TS_RFC2822 );
                }
                if ( $config->get( MainConfigNames::VaryOnXFP ) ) {
                    $this->addVaryHeader( 'X-Forwarded-Proto' );
                }
                $this->sendCacheControl();
 
                $response->header( 'Content-Type: text/html; charset=UTF-8' );
                if ( $config->get( MainConfigNames::DebugRedirects ) ) {
                    $url = htmlspecialchars( $redirect );
                    $content = "<!DOCTYPE html>\n<html>\n<head>\n"
                        . "<title>Redirect</title>\n</head>\n<body>\n"
                        . "<p>Location: <a href=\"$url\">$url</a></p>\n"
                        . "</body>\n</html>\n";
 
                    if ( !$return ) {
                        print $content;
                    }
 
                } else {
                    $response->header( 'Location: ' . $redirect );
                }
            }
 
            return $return ? $content : null;
        } elseif ( $this->mStatusCode ) {
            $response->statusHeader( $this->mStatusCode );
        }
 
        # Buffer output; final headers may depend on later processing
        ob_start();
 
        $response->header( 'Content-language: ' .
            MediaWikiServices::getInstance()->getContentLanguage()->getHtmlCode() );
 
        $linkHeader = $this->getLinkHeader();
        if ( $linkHeader ) {
            $response->header( $linkHeader );
        }
 
        // Prevent framing, if requested
        $frameOptions = $this->getFrameOptions();
        if ( $frameOptions ) {
            $response->header( "X-Frame-Options: $frameOptions" );
        }
 
        // Get the Origin-Trial header values. This is used to enable Chrome Origin
        // Trials: https://github.com/GoogleChrome/OriginTrials
        $originTrials = $config->get( MainConfigNames::OriginTrials );
        foreach ( $originTrials as $originTrial ) {
            $response->header( "Origin-Trial: $originTrial", false );
        }
 
        $reportTo = $this->getReportTo();
        if ( $reportTo ) {
            $response->header( "Report-To: $reportTo" );
        }
 
        $featurePolicyReportOnly = $this->getFeaturePolicyReportOnly();
        if ( $featurePolicyReportOnly ) {
            $response->header( "Feature-Policy-Report-Only: $featurePolicyReportOnly" );
        }
 
        if ( $this->mArticleBodyOnly ) {
            $response->header( 'Content-type: ' . $config->get( MainConfigNames::MimeType ) . '; charset=UTF-8' );
            if ( $this->cspOutputMode === self::CSP_HEADERS ) {
                $this->CSP->sendHeaders();
            }
            echo $this->mBodytext;
        } else {
            // Enable safe mode if requested (T152169)
            if ( $this->getRequest()->getBool( 'safemode' ) ) {
                $this->disallowUserJs();
            }
 
            $sk = $this->getSkin();
            $skinOptions = $sk->getOptions();
 
            if ( $skinOptions['format'] === 'json' ) {
                $response->header( 'Content-type: application/json; charset=UTF-8' );
                return json_encode( [
                    $this->msg( 'skin-json-warning' )->escaped() => $this->msg( 'skin-json-warning-message' )->escaped()
                ] + $sk->getTemplateData() );
            }
            $response->header( 'Content-type: ' . $config->get( MainConfigNames::MimeType ) . '; charset=UTF-8' );
            $this->loadSkinModules( $sk );
 
            MWDebug::addModules( $this );
 
            // Hook that allows last minute changes to the output page, e.g.
            // adding of CSS or Javascript by extensions, adding CSP sources.
            $this->getHookRunner()->onBeforePageDisplay( $this, $sk );
 
            if ( $this->cspOutputMode === self::CSP_HEADERS ) {
                $this->CSP->sendHeaders();
            }
 
            try {
                $sk->outputPage();
            } catch ( Exception $e ) {
                ob_end_clean(); // bug T129657
                throw $e;
            }
        }
 
        try {
            // This hook allows last minute changes to final overall output by modifying output buffer
            $this->getHookRunner()->onAfterFinalPageOutput( $this );
        } catch ( Exception $e ) {
            ob_end_clean(); // bug T129657
            throw $e;
        }
 
        $this->sendCacheControl();
 
        if ( $return ) {
            return ob_get_clean();
        } else {
            ob_end_flush();
            return null;
        }
    }
 
    public function prepareErrorPage( $pageTitle = null, $htmlTitle = false ) {
        if ( $pageTitle !== null || $htmlTitle !== false ) {
            wfDeprecated( __METHOD__ . ' with explicit arguments', '1.41' );
            if ( $pageTitle !== null ) {
                $this->setPageTitle( $pageTitle );
            }
            if ( $htmlTitle !== false ) {
                $this->setHTMLTitle( $htmlTitle );
            }
        }
        $this->setRobotPolicy( 'noindex,nofollow' );
        $this->setArticleRelated( false );
        $this->disableClientCache();
        $this->mRedirect = '';
        $this->clearSubtitle();
        $this->clearHTML();
    }
 
    public function showErrorPage(
        $title, $msg, $params = [], $returnto = null, $returntoquery = null
    ) {
        if ( !$title instanceof Message ) {
            $title = $this->msg( $title );
        }
 
        $this->prepareErrorPage();
        $this->setPageTitleMsg( $title );
 
        if ( $msg instanceof Message ) {
            if ( $params !== [] ) {
                trigger_error( 'Argument ignored: $params. The message parameters argument '
                    . 'is discarded when the $msg argument is a Message object instead of '
                    . 'a string.', E_USER_NOTICE );
            }
            $this->addHTML( $msg->parseAsBlock() );
        } else {
            $this->addWikiMsgArray( $msg, $params );
        }
 
        $this->returnToMain( null, $returnto, $returntoquery );
    }
 
    public function showPermissionsErrorPage( array $errors, $action = null ) {
        $services = MediaWikiServices::getInstance();
        $groupPermissionsLookup = $services->getGroupPermissionsLookup();
        foreach ( $errors as $key => $error ) {
            $errors[$key] = (array)$error;
        }
 
        // For some actions (read, edit, create and upload), display a "login to do this action"
        // error if all of the following conditions are met:
        // 1. the user is not logged in as a named user, and so cannot be added to groups
        // 2. the only error is insufficient permissions (i.e. no block or something else)
        // 3. the error can be avoided simply by logging in
 
        if ( in_array( $action, [ 'read', 'edit', 'createpage', 'createtalk', 'upload' ] )
            && !$this->getUser()->isNamed() && count( $errors ) == 1 && isset( $errors[0][0] )
            && ( $errors[0][0] == 'badaccess-groups' || $errors[0][0] == 'badaccess-group0' )
            && ( $groupPermissionsLookup->groupHasPermission( 'user', $action )
                || $groupPermissionsLookup->groupHasPermission( 'autoconfirmed', $action ) )
        ) {
            $displayReturnto = null;
 
            # Due to T34276, if a user does not have read permissions,
            # $this->getTitle() will just give Special:Badtitle, which is
            # not especially useful as a returnto parameter. Use the title
            # from the request instead, if there was one.
            $request = $this->getRequest();
            $returnto = Title::newFromText( $request->getText( 'title' ) );
            if ( $action == 'edit' ) {
                $msg = 'whitelistedittext';
                $displayReturnto = $returnto;
            } elseif ( $action == 'createpage' || $action == 'createtalk' ) {
                $msg = 'nocreatetext';
            } elseif ( $action == 'upload' ) {
                $msg = 'uploadnologintext';
            } else { # Read
                $msg = 'loginreqpagetext';
                $displayReturnto = Title::newMainPage();
            }
 
            $query = [];
 
            if ( $returnto ) {
                $query['returnto'] = $returnto->getPrefixedText();
 
                if ( !$request->wasPosted() ) {
                    $returntoquery = $request->getValues();
                    unset( $returntoquery['title'] );
                    unset( $returntoquery['returnto'] );
                    unset( $returntoquery['returntoquery'] );
                    $query['returntoquery'] = wfArrayToCgi( $returntoquery );
                }
            }
 
            $title = SpecialPage::getTitleFor( 'Userlogin' );
            $linkRenderer = $services->getLinkRenderer();
            $loginUrl = $title->getLinkURL( $query, false, PROTO_RELATIVE );
            $loginLink = $linkRenderer->makeKnownLink(
                $title,
                $this->msg( 'loginreqlink' )->text(),
                [],
                $query
            );
 
            $this->prepareErrorPage();
            $this->setPageTitleMsg( $this->msg( 'loginreqtitle' ) );
            $this->addHTML( $this->msg( $msg )->rawParams( $loginLink )->params( $loginUrl )->parse() );
 
            # Don't return to a page the user can't read otherwise
            # we'll end up in a pointless loop
            if ( $displayReturnto && $this->getAuthority()->probablyCan( 'read', $displayReturnto ) ) {
                $this->returnToMain( null, $displayReturnto );
            }
        } else {
            $this->prepareErrorPage();
            $this->setPageTitleMsg( $this->msg( 'permissionserrors' ) );
            $this->addWikiTextAsInterface( $this->formatPermissionsErrorMessage( $errors, $action ) );
        }
    }
 
    public function versionRequired( $version ) {
        $this->prepareErrorPage();
        $this->setPageTitleMsg(
            $this->msg( 'versionrequired' )->plaintextParams( $version )
        );
 
        $this->addWikiMsg( 'versionrequiredtext', $version );
        $this->returnToMain();
    }
 
    public function formatPermissionStatus( PermissionStatus $status, string $action = null ): string {
        if ( $status->isGood() ) {
            return '';
        }
        return $this->formatPermissionInternal(
            array_map( fn ( $msg ) => $this->msg( $msg ), $status->getMessages() ),
            $action
        );
    }
 
    public function formatPermissionsErrorMessage( array $errors, $action = null ) {
        return $this->formatPermissionInternal(
            // @phan-suppress-next-line PhanParamTooFewUnpack Elements of $errors already annotated as non-empty
            array_map( fn ( $err ) => $this->msg( ...$err ), $errors ),
            $action
        );
    }
 
    private function formatPermissionInternal( array $messages, $action = null ) {
        if ( $action == null ) {
            $text = $this->msg( 'permissionserrorstext', count( $messages ) )->plain() . "\n\n";
        } else {
            $action_desc = $this->msg( "action-$action" )->plain();
            $text = $this->msg(
                'permissionserrorstext-withaction',
                count( $messages ),
                $action_desc
            )->plain() . "\n\n";
        }
 
        if ( count( $messages ) > 1 ) {
            $text .= Html::openElement( 'ul', [ 'class' => 'permissions-errors' ] );
            foreach ( $messages as $message ) {
                $text .= Html::rawElement(
                    'li',
                    [ 'class' => 'mw-permissionerror-' . $message->getKey() ],
                    $message->plain()
                );
            }
            $text .= Html::closeElement( 'ul' );
        } else {
            $text .= Html::openElement( 'div', [ 'class' => 'permissions-errors' ] );
            $text .= Html::rawElement(
                'div',
                [ 'class' => 'mw-permissionerror-' . $messages[ 0 ]->getKey() ],
                $messages[ 0 ]->plain()
            );
            $text .= Html::closeElement( 'div' );
        }
 
        return $text;
    }
 
    public function showLagWarning( $lag ) {
        $config = $this->getConfig();
        if ( $lag >= $config->get( MainConfigNames::DatabaseReplicaLagWarning ) ) {
            $lag = floor( $lag ); // floor to avoid nano seconds to display
            $message = $lag < $config->get( MainConfigNames::DatabaseReplicaLagCritical )
                ? 'lag-warn-normal'
                : 'lag-warn-high';
            // For grep: mw-lag-warn-normal, mw-lag-warn-high
            $wrap = Html::rawElement( 'div', [ 'class' => "mw-{$message}" ], "\n$1\n" );
            $this->wrapWikiMsg( "$wrap\n", [ $message, $this->getLanguage()->formatNum( $lag ) ] );
        }
    }
 
    public function showFatalError( $message ) {
        wfDeprecated( __METHOD__, '1.43' );
 
        $this->prepareErrorPage();
        $this->setPageTitleMsg( $this->msg( 'internalerror' ) );
 
        $this->addHTML( $message );
    }
 
    public function addReturnTo( $title, array $query = [], $text = null, $options = [] ) {
        $linkRenderer = MediaWikiServices::getInstance()
            ->getLinkRendererFactory()->createFromLegacyOptions( $options );
        $link = $this->msg( 'returnto' )->rawParams(
            $linkRenderer->makeLink( $title, $text, [], $query ) )->escaped();
        $this->addHTML( "<p id=\"mw-returnto\">{$link}</p>\n" );
    }
 
    public function returnToMain( $unused = null, $returnto = null, $returntoquery = null ) {
        $returnto ??= $this->getRequest()->getText( 'returnto' );
 
        $returntoquery ??= $this->getRequest()->getText( 'returntoquery' );
 
        if ( $returnto === '' ) {
            $returnto = Title::newMainPage();
        }
 
        if ( is_object( $returnto ) ) {
            $linkTarget = TitleValue::castPageToLinkTarget( $returnto );
        } else {
            $linkTarget = Title::newFromText( $returnto );
        }
 
        // We don't want people to return to external interwiki. That
        // might potentially be used as part of a phishing scheme
        if ( !is_object( $linkTarget ) || $linkTarget->isExternal() ) {
            $linkTarget = Title::newMainPage();
        }
 
        $this->addReturnTo( $linkTarget, wfCgiToArray( $returntoquery ) );
    }
 
    public function showPendingTakeover(
        $fallbackUrl, $msg, ...$params
    ) {
        if ( $msg instanceof Message ) {
            if ( $params !== [] ) {
                trigger_error( 'Argument ignored: $params. The message parameters argument '
                    . 'is discarded when the $msg argument is a Message object instead of '
                    . 'a string.', E_USER_NOTICE );
            }
            $this->addHTML( $msg->parseAsBlock() );
        } else {
            $this->addHTML( $this->msg( $msg, ...$params )->parseAsBlock() );
        }
 
        // Redirect if the user has no JS (<noscript>)
        $escapedUrl = htmlspecialchars( $fallbackUrl );
        $this->addHeadItem(
            'mw-noscript-fallback',
            // https://html.spec.whatwg.org/#attr-meta-http-equiv-refresh
            // means that if $fallbackUrl contains unencoded quotation marks
            // then this will behave confusingly, but shouldn't break the page
            "<noscript><meta http-equiv=\"refresh\" content=\"0; url=$escapedUrl\"></noscript>"
        );
        // Redirect if the user has no ResourceLoader
        $this->addScript( Html::inlineScript(
            '(window.NORLQ=window.NORLQ||[]).push(' .
                'function(){' .
                    'location.href=' . json_encode( $fallbackUrl ) . ';' .
                '}' .
            ');'
        ) );
    }
 
    private function getRlClientContext() {
        if ( !$this->rlClientContext ) {
            $query = ResourceLoader::makeLoaderQuery(
                [], // modules; not relevant
                $this->getLanguage()->getCode(),
                $this->getSkin()->getSkinName(),
                $this->getUser()->isRegistered() ? $this->getUser()->getName() : null,
                null, // version; not relevant
                ResourceLoader::inDebugMode(),
                null, // only; not relevant
                $this->isPrintable()
            );
            $this->rlClientContext = new RL\Context(
                $this->getResourceLoader(),
                new FauxRequest( $query )
            );
            if ( $this->contentOverrideCallbacks ) {
                $this->rlClientContext = new RL\DerivativeContext( $this->rlClientContext );
                $this->rlClientContext->setContentOverrideCallback( function ( $page ) {
                    foreach ( $this->contentOverrideCallbacks as $callback ) {
                        $content = $callback( $page );
                        if ( $content !== null ) {
                            $text = ( $content instanceof TextContent ) ? $content->getText() : '';
                            if ( preg_match( '/<\/?script/i', $text ) ) {
                                // Proactively replace this so that we can display a message
                                // to the user, instead of letting it go to Html::inlineScript(),
                                // where it would be considered a server-side issue.
                                $content = new JavaScriptContent(
                                    Html::encodeJsCall( 'mw.log.error', [
                                        "Cannot preview $page due to suspecting script tag inside (T200506)."
                                    ] )
                                );
                            }
                            return $content;
                        }
                    }
                    return null;
                } );
            }
        }
        return $this->rlClientContext;
    }
 
    public function getRlClient() {
        if ( !$this->rlClient ) {
            $context = $this->getRlClientContext();
            $rl = $this->getResourceLoader();
            $this->addModules( [
                'user',
                'user.options',
            ] );
            $this->addModuleStyles( [
                'site.styles',
                'noscript',
                'user.styles',
            ] );
 
            // Prepare exempt modules for buildExemptModules()
            $exemptGroups = [
                RL\Module::GROUP_SITE => [],
                RL\Module::GROUP_NOSCRIPT => [],
                RL\Module::GROUP_PRIVATE => [],
                RL\Module::GROUP_USER => []
            ];
            $exemptStates = [];
            $moduleStyles = $this->getModuleStyles( /*filter*/ true );
 
            // Preload getTitleInfo for isKnownEmpty calls below and in RL\ClientHtml
            // Separate user-specific batch for improved cache-hit ratio.
            $userBatch = [ 'user.styles', 'user' ];
            $siteBatch = array_diff( $moduleStyles, $userBatch );
            RL\WikiModule::preloadTitleInfo( $context, $siteBatch );
            RL\WikiModule::preloadTitleInfo( $context, $userBatch );
 
            // Filter out modules handled by buildExemptModules()
            $moduleStyles = array_filter( $moduleStyles,
                static function ( $name ) use ( $rl, $context, &$exemptGroups, &$exemptStates ) {
                    $module = $rl->getModule( $name );
                    if ( $module ) {
                        $group = $module->getGroup();
                        if ( $group !== null && isset( $exemptGroups[$group] ) ) {
                            // The `noscript` module is excluded from the client
                            // side registry, no need to set its state either.
                            // But we still output it. See T291735
                            if ( $group !== RL\Module::GROUP_NOSCRIPT ) {
                                $exemptStates[$name] = 'ready';
                            }
                            if ( !$module->isKnownEmpty( $context ) ) {
                                // E.g. Don't output empty <styles>
                                $exemptGroups[$group][] = $name;
                            }
                            return false;
                        }
                    }
                    return true;
                }
            );
            $this->rlExemptStyleModules = $exemptGroups;
 
            $config = $this->getConfig();
            // Client preferences are controlled by the skin and specific to unregistered
            // users. See mw.user.clientPrefs for details on how this works and how to
            // handle registered users.
            $clientPrefEnabled = (
                $this->getSkin()->getOptions()['clientPrefEnabled'] &&
                !$this->getUser()->isNamed()
            );
            $clientPrefCookiePrefix = $config->get( MainConfigNames::CookiePrefix );
 
            $rlClient = new RL\ClientHtml( $context, [
                'target' => $this->getTarget(),
                // When 'safemode', disallowUserJs(), or reduceAllowedModules() is used
                // to only restrict modules to ORIGIN_CORE (ie. disallow ORIGIN_USER), the list of
                // modules enqueued for loading on this page is filtered to just those.
                // However, to make sure we also apply the restriction to dynamic dependencies and
                // lazy-loaded modules at run-time on the client-side, pass 'safemode' down to the
                // StartupModule so that the client-side registry will not contain any restricted
                // modules either. (T152169, T185303)
                'safemode' => ( $this->getAllowedModules( RL\Module::TYPE_COMBINED )
                    <= RL\Module::ORIGIN_CORE_INDIVIDUAL
                ) ? '1' : null,
                'clientPrefEnabled' => $clientPrefEnabled,
                'clientPrefCookiePrefix' => $clientPrefCookiePrefix,
            ] );
            $rlClient->setConfig( $this->getJSVars( self::JS_VAR_EARLY ) );
            $rlClient->setModules( $this->getModules( /*filter*/ true ) );
            $rlClient->setModuleStyles( $moduleStyles );
            $rlClient->setExemptStates( $exemptStates );
            $this->rlClient = $rlClient;
        }
        return $this->rlClient;
    }
 
    public function headElement( Skin $sk, $includeStyle = true ) {
        $config = $this->getConfig();
        $userdir = $this->getLanguage()->getDir();
        $services = MediaWikiServices::getInstance();
        $sitedir = $services->getContentLanguage()->getDir();
 
        $pieces = [];
        $htmlAttribs = Sanitizer::mergeAttributes( Sanitizer::mergeAttributes(
            $this->getRlClient()->getDocumentAttributes(),
            $sk->getHtmlElementAttributes()
        ), [ 'class' => implode( ' ', $this->mAdditionalHtmlClasses ) ] );
        $pieces[] = Html::htmlHeader( $htmlAttribs );
        $pieces[] = Html::openElement( 'head' );
 
        if ( $this->getHTMLTitle() == '' ) {
            $this->setHTMLTitle( $this->msg( 'pagetitle', $this->getPageTitle() )->inContentLanguage() );
        }
 
        if ( !Html::isXmlMimeType( $config->get( MainConfigNames::MimeType ) ) ) {
            // Add <meta charset="UTF-8">
            // This should be before <title> since it defines the charset used by
            // text including the text inside <title>.
            // The spec recommends defining XHTML5's charset using the XML declaration
            // instead of meta.
            // Our XML declaration is output by Html::htmlHeader.
            // https://html.spec.whatwg.org/multipage/semantics.html#attr-meta-http-equiv-content-type
            // https://html.spec.whatwg.org/multipage/semantics.html#charset
            $pieces[] = Html::element( 'meta', [ 'charset' => 'UTF-8' ] );
        }
 
        $pieces[] = Html::element( 'title', [], $this->getHTMLTitle() );
        $pieces[] = $this->getRlClient()->getHeadHtml( $htmlAttribs['class'] ?? null );
        $pieces[] = $this->buildExemptModules();
        $pieces = array_merge( $pieces, array_values( $this->getHeadLinksArray() ) );
        $pieces = array_merge( $pieces, array_values( $this->mHeadItems ) );
 
        $pieces[] = Html::closeElement( 'head' );
 
        $skinOptions = $sk->getOptions();
        $bodyClasses = array_merge( $this->mAdditionalBodyClasses, $skinOptions['bodyClasses'] );
        $bodyClasses[] = 'mediawiki';
 
        # Classes for LTR/RTL directionality support
        $bodyClasses[] = $userdir;
        $bodyClasses[] = "sitedir-$sitedir";
 
        // See Article:showDiffPage for class to support article diff styling
 
        $underline = $services->getUserOptionsLookup()->getOption( $this->getUser(), 'underline' );
        if ( $underline < 2 ) {
            // The following classes can be used here:
            // * mw-underline-always
            // * mw-underline-never
            $bodyClasses[] = 'mw-underline-' . ( $underline ? 'always' : 'never' );
        }
 
        // Parser feature migration class
        // The idea is that this will eventually be removed, after the wikitext
        // which requires it is cleaned up.
        $bodyClasses[] = 'mw-hide-empty-elt';
 
        $bodyClasses[] = $sk->getPageClasses( $this->getTitle() );
        $bodyClasses[] = 'skin-' . Sanitizer::escapeClass( $sk->getSkinName() );
        $bodyClasses[] =
            'action-' . Sanitizer::escapeClass( $this->getContext()->getActionName() );
 
        if ( $sk->isResponsive() ) {
            $bodyClasses[] = 'skin--responsive';
        }
 
        $bodyAttrs = [];
        // While the implode() is not strictly needed, it's used for backwards compatibility
        // (this used to be built as a string and hooks likely still expect that).
        $bodyAttrs['class'] = implode( ' ', $bodyClasses );
 
        // Allow skins and extensions to add body attributes they need
        // Get ones from deprecated method
        if ( method_exists( $sk, 'addToBodyAttributes' ) ) {
            $sk->addToBodyAttributes( $this, $bodyAttrs );
            wfDeprecated( 'Skin::addToBodyAttributes method to add body attributes', '1.35' );
        }
 
        // Then run the hook, the recommended way of adding body attributes now
        $this->getHookRunner()->onOutputPageBodyAttributes( $this, $sk, $bodyAttrs );
 
        $pieces[] = Html::openElement( 'body', $bodyAttrs );
 
        return self::combineWrappedStrings( $pieces );
    }
 
    public function getResourceLoader() {
        if ( $this->mResourceLoader === null ) {
            // Lazy-initialise as needed
            $this->mResourceLoader = MediaWikiServices::getInstance()->getResourceLoader();
        }
        return $this->mResourceLoader;
    }
 
    public function makeResourceLoaderLink( $modules, $only, array $extraQuery = [] ) {
        // Apply 'origin' filters
        $modules = $this->filterModules( (array)$modules, null, $only );
 
        return RL\ClientHtml::makeLoad(
            $this->getRlClientContext(),
            $modules,
            $only,
            $extraQuery
        );
    }
 
    protected static function combineWrappedStrings( array $chunks ) {
        // Filter out empty values
        $chunks = array_filter( $chunks, 'strlen' );
        return WrappedString::join( "\n", $chunks );
    }
 
    public function getBottomScripts() {
        // Keep the hook appendage separate to preserve WrappedString objects.
        // This enables to merge them where possible.
        $extraHtml = '';
        $this->getHookRunner()->onSkinAfterBottomScripts( $this->getSkin(), $extraHtml );
 
        $chunks = [];
        $chunks[] = $this->getRlClient()->getBodyHtml();
 
        // Legacy non-ResourceLoader scripts
        $chunks[] = $this->mScripts;
 
        // Keep hostname and backend time as the first variables for quick view-source access.
        // This other variables will form a very long inline blob.
        $vars = [];
        if ( $this->getConfig()->get( MainConfigNames::ShowHostnames ) ) {
            $vars['wgHostname'] = wfHostname();
        }
        $elapsed = $this->getRequest()->getElapsedTime();
        // seconds to milliseconds
        $vars['wgBackendResponseTime'] = round( $elapsed * 1000 );
 
        $vars += $this->getJSVars( self::JS_VAR_LATE );
        if ( $this->limitReportJSData ) {
            $vars['wgPageParseReport'] = $this->limitReportJSData;
        }
 
        $rlContext = $this->getRlClientContext();
        $chunks[] = ResourceLoader::makeInlineScript(
            'mw.config.set(' . $rlContext->encodeJson( $vars ) . ');'
        );
 
        $chunks = [ self::combineWrappedStrings( $chunks ) ];
        if ( $extraHtml !== '' ) {
            $chunks[] = $extraHtml;
        }
 
        return WrappedString::join( "\n", $chunks );
    }
 
    public function getJsConfigVars() {
        return $this->mJsConfigVars;
    }
 
    public function addJsConfigVars( $keys, $value = null ) {
        if ( is_array( $keys ) ) {
            foreach ( $keys as $key => $value ) {
                $this->mJsConfigVars[$key] = $value;
            }
            return;
        }
 
        $this->mJsConfigVars[$keys] = $value;
    }
 
    public function getJSVars( ?int $flag = null ) {
        $curRevisionId = 0;
        $articleId = 0;
        $canonicalSpecialPageName = false; # T23115
        $services = MediaWikiServices::getInstance();
 
        $title = $this->getTitle();
        $ns = $title->getNamespace();
        $nsInfo = $services->getNamespaceInfo();
        $canonicalNamespace = $nsInfo->exists( $ns )
            ? $nsInfo->getCanonicalName( $ns )
            : $title->getNsText();
 
        $sk = $this->getSkin();
        // Get the relevant title so that AJAX features can use the correct page name
        // when making API requests from certain special pages (T36972).
        $relevantTitle = $sk->getRelevantTitle();
 
        if ( $ns === NS_SPECIAL ) {
            [ $canonicalSpecialPageName, /*...*/ ] =
                $services->getSpecialPageFactory()->
                    resolveAlias( $title->getDBkey() );
        } elseif ( $this->canUseWikiPage() ) {
            $wikiPage = $this->getWikiPage();
            // If we already know that the latest revision ID is the same as the revision ID being viewed,
            // avoid fetching it again, as it may give inconsistent results (T339164).
            if ( $this->isRevisionCurrent() && $this->getRevisionId() ) {
                $curRevisionId = $this->getRevisionId();
            } else {
                $curRevisionId = $wikiPage->getLatest();
            }
            $articleId = $wikiPage->getId();
        }
 
        // ParserOutput informs HTML/CSS via lang/dir attributes.
        // We inform JavaScript via mw.config from here.
        $lang = $this->getContentLangForJS();
 
        // Pre-process information
        $separatorTransTable = $lang->separatorTransformTable();
        $separatorTransTable = $separatorTransTable ?: [];
        $compactSeparatorTransTable = [
            implode( "\t", array_keys( $separatorTransTable ) ),
            implode( "\t", $separatorTransTable ),
        ];
        $digitTransTable = $lang->digitTransformTable();
        $digitTransTable = $digitTransTable ?: [];
        $compactDigitTransTable = [
            implode( "\t", array_keys( $digitTransTable ) ),
            implode( "\t", $digitTransTable ),
        ];
 
        $user = $this->getUser();
 
        // Internal variables for MediaWiki core
        $vars = [
            // @internal For mediawiki.page.ready
            'wgBreakFrames' => $this->getFrameOptions() == 'DENY',
 
            // @internal For jquery.tablesorter
            'wgSeparatorTransformTable' => $compactSeparatorTransTable,
            'wgDigitTransformTable' => $compactDigitTransTable,
            'wgDefaultDateFormat' => $lang->getDefaultDateFormat(),
            'wgMonthNames' => $lang->getMonthNamesArray(),
 
            // @internal For debugging purposes
            'wgRequestId' => WebRequest::getRequestId(),
        ];
 
        // Start of supported and stable config vars (for use by extensions/gadgets).
        $vars += [
            'wgCanonicalNamespace' => $canonicalNamespace,
            'wgCanonicalSpecialPageName' => $canonicalSpecialPageName,
            'wgNamespaceNumber' => $title->getNamespace(),
            'wgPageName' => $title->getPrefixedDBkey(),
            'wgTitle' => $title->getText(),
            'wgCurRevisionId' => $curRevisionId,
            'wgRevisionId' => (int)$this->getRevisionId(),
            'wgArticleId' => $articleId,
            'wgIsArticle' => $this->isArticle(),
            'wgIsRedirect' => $title->isRedirect(),
            'wgAction' => $this->getContext()->getActionName(),
            'wgUserName' => $user->isAnon() ? null : $user->getName(),
            'wgUserGroups' => $services->getUserGroupManager()->getUserEffectiveGroups( $user ),
            'wgCategories' => $this->getCategories(),
            'wgPageViewLanguage' => $lang->getCode(),
            'wgPageContentLanguage' => $lang->getCode(),
            'wgPageContentModel' => $title->getContentModel(),
            'wgRelevantPageName' => $relevantTitle->getPrefixedDBkey(),
            'wgRelevantArticleId' => $relevantTitle->getArticleID(),
        ];
        if ( $user->isRegistered() ) {
            $vars['wgUserId'] = $user->getId();
            $vars['wgUserIsTemp'] = $user->isTemp();
            $vars['wgUserEditCount'] = $user->getEditCount();
            $userReg = $user->getRegistration();
            $vars['wgUserRegistration'] = $userReg ? (int)wfTimestamp( TS_UNIX, $userReg ) * 1000 : null;
            $userFirstReg = $services->getUserRegistrationLookup()->getFirstRegistration( $user );
            $vars['wgUserFirstRegistration'] = $userFirstReg ? (int)wfTimestamp( TS_UNIX, $userFirstReg ) * 1000 : null;
            // Get the revision ID of the oldest new message on the user's talk
            // page. This can be used for constructing new message alerts on
            // the client side.
            $userNewMsgRevId = $this->getLastSeenUserTalkRevId();
            // Only occupy precious space in the <head> when it is non-null (T53640)
            // mw.config.get returns null by default.
            if ( $userNewMsgRevId ) {
                $vars['wgUserNewMsgRevisionId'] = $userNewMsgRevId;
            }
        } else {
            $tempUserCreator = $services->getTempUserCreator();
            if ( $tempUserCreator->isEnabled() ) {
                // For logged-out users only (without a temporary account): get the user name that will
                // be used for their temporary account, if it has already been acquired.
                // This may be used in previews.
                $session = $this->getRequest()->getSession();
                $vars['wgTempUserName'] = $tempUserCreator->getStashedName( $session );
            }
        }
        $languageConverter = $services->getLanguageConverterFactory()
            ->getLanguageConverter( $title->getPageLanguage() );
        if ( $languageConverter->hasVariants() ) {
            $vars['wgUserVariant'] = $languageConverter->getPreferredVariant();
        }
        // Same test as SkinTemplate
        $vars['wgIsProbablyEditable'] = $this->getAuthority()->probablyCan( 'edit', $title );
        $vars['wgRelevantPageIsProbablyEditable'] = $relevantTitle &&
            $this->getAuthority()->probablyCan( 'edit', $relevantTitle );
        $restrictionStore = $services->getRestrictionStore();
        foreach ( $restrictionStore->listApplicableRestrictionTypes( $title ) as $type ) {
            // Following keys are set in $vars:
            // wgRestrictionCreate, wgRestrictionEdit, wgRestrictionMove, wgRestrictionUpload
            $vars['wgRestriction' . ucfirst( $type )] = $restrictionStore->getRestrictions( $title, $type );
        }
        if ( $title->isMainPage() ) {
            $vars['wgIsMainPage'] = true;
        }
 
        $relevantUser = $sk->getRelevantUser();
        if ( $relevantUser ) {
            $vars['wgRelevantUserName'] = $relevantUser->getName();
        }
        // End of stable config vars
 
        $titleFormatter = $services->getTitleFormatter();
 
        if ( $this->mRedirectedFrom ) {
            // @internal For skin JS
            $vars['wgRedirectedFrom'] = $titleFormatter->getPrefixedDBkey( $this->mRedirectedFrom );
        }
 
        // Allow extensions to add their custom variables to the mw.config map.
        // Use the 'ResourceLoaderGetConfigVars' hook if the variable is not
        // page-dependent but site-wide (without state).
        // Alternatively, you may want to use OutputPage->addJsConfigVars() instead.
        $this->getHookRunner()->onMakeGlobalVariablesScript( $vars, $this );
 
        // Merge in variables from addJsConfigVars last
        $vars = array_merge( $vars, $this->getJsConfigVars() );
 
        // Return only early or late vars if requested
        if ( $flag !== null ) {
            $lateVarNames =
                array_fill_keys( self::CORE_LATE_JS_CONFIG_VAR_NAMES, true ) +
                array_fill_keys( ExtensionRegistry::getInstance()->getAttribute( 'LateJSConfigVarNames' ), true );
            foreach ( $vars as $name => $_ ) {
                // If the variable's late flag doesn't match the requested late flag, unset it
                if ( isset( $lateVarNames[ $name ] ) !== ( $flag === self::JS_VAR_LATE ) ) {
                    unset( $vars[ $name ] );
                }
            }
        }
 
        return $vars;
    }
 
    private function getLastSeenUserTalkRevId() {
        $services = MediaWikiServices::getInstance();
        $user = $this->getUser();
        $userHasNewMessages = $services
            ->getTalkPageNotificationManager()
            ->userHasNewMessages( $user );
        if ( !$userHasNewMessages ) {
            return null;
        }
 
        $timestamp = $services
            ->getTalkPageNotificationManager()
            ->getLatestSeenMessageTimestamp( $user );
        if ( !$timestamp ) {
            return null;
        }
 
        $revRecord = $services->getRevisionLookup()->getRevisionByTimestamp(
            $user->getTalkPage(),
            $timestamp
        );
        return $revRecord ? $revRecord->getId() : null;
    }
 
    public function userCanPreview() {
        $request = $this->getRequest();
        if (
            $request->getRawVal( 'action' ) !== 'submit' ||
            !$request->wasPosted()
        ) {
            return false;
        }
 
        $user = $this->getUser();
 
        if ( !$user->isRegistered() ) {
            // Anons have predictable edit tokens
            return false;
        }
        if ( !$user->matchEditToken( $request->getVal( 'wpEditToken' ) ) ) {
            return false;
        }
 
        $title = $this->getTitle();
        if ( !$this->getAuthority()->probablyCan( 'edit', $title ) ) {
            return false;
        }
 
        return true;
    }
 
    public function getHeadLinksArray() {
        $tags = [];
        $config = $this->getConfig();
 
        if ( $this->cspOutputMode === self::CSP_META ) {
            foreach ( $this->CSP->getDirectives() as $header => $directive ) {
                $tags["meta-csp-$header"] = Html::element( 'meta', [
                    'http-equiv' => $header,
                    'content' => $directive,
                ] );
            }
        }
 
        $tags['meta-generator'] = Html::element( 'meta', [
            'name' => 'generator',
            'content' => 'MediaWiki ' . MW_VERSION,
        ] );
 
        if ( $config->get( MainConfigNames::ReferrerPolicy ) !== false ) {
            // Per https://w3c.github.io/webappsec-referrer-policy/#unknown-policy-values
            // fallbacks should come before the primary value so we need to reverse the array.
            foreach ( array_reverse( (array)$config->get( MainConfigNames::ReferrerPolicy ) ) as $i => $policy ) {
                $tags["meta-referrer-$i"] = Html::element( 'meta', [
                    'name' => 'referrer',
                    'content' => $policy,
                ] );
            }
        }
 
        $p = $this->getRobotsContent();
        if ( $p ) {
            // http://www.robotstxt.org/wc/meta-user.html
            // Only show if it's different from the default robots policy
            $tags['meta-robots'] = Html::element( 'meta', [
                'name' => 'robots',
                'content' => $p,
            ] );
        }
 
        # Browser based phonenumber detection
        if ( $config->get( MainConfigNames::BrowserFormatDetection ) !== false ) {
            $tags['meta-format-detection'] = Html::element( 'meta', [
                'name' => 'format-detection',
                'content' => $config->get( MainConfigNames::BrowserFormatDetection ),
            ] );
        }
 
        foreach ( $this->mMetatags as [ $name, $val ] ) {
            $attrs = [];
            if ( strncasecmp( $name, 'http:', 5 ) === 0 ) {
                $name = substr( $name, 5 );
                $attrs['http-equiv'] = $name;
            } elseif ( strncasecmp( $name, 'og:', 3 ) === 0 ) {
                $attrs['property'] = $name;
            } else {
                $attrs['name'] = $name;
            }
            $attrs['content'] = $val;
            $tagName = "meta-$name";
            if ( isset( $tags[$tagName] ) ) {
                $tagName .= $val;
            }
            $tags[$tagName] = Html::element( 'meta', $attrs );
        }
 
        foreach ( $this->mLinktags as $tag ) {
            $tags[] = Html::element( 'link', $tag );
        }
 
        if ( $config->get( MainConfigNames::UniversalEditButton ) && $this->isArticleRelated() ) {
            if ( $this->getAuthority()->probablyCan( 'edit', $this->getTitle() ) ) {
                $msg = $this->msg( 'edit' )->text();
                // Use mime type per https://phabricator.wikimedia.org/T21165#6946526
                $tags['universal-edit-button'] = Html::element( 'link', [
                    'rel' => 'alternate',
                    'type' => 'application/x-wiki',
                    'title' => $msg,
                    'href' => $this->getTitle()->getEditURL(),
                ] );
            }
        }
 
        # Generally the order of the favicon and apple-touch-icon links
        # should not matter, but Konqueror (3.5.9 at least) incorrectly
        # uses whichever one appears later in the HTML source. Make sure
        # apple-touch-icon is specified first to avoid this.
        $appleTouchIconHref = $config->get( MainConfigNames::AppleTouchIcon );
        # Browser look for those by default, unnessecary to set a link tag
        if (
            $appleTouchIconHref !== false &&
            $appleTouchIconHref !== '/apple-touch-icon.png' &&
            $appleTouchIconHref !== '/apple-touch-icon-precomposed.png'
        ) {
            $tags['apple-touch-icon'] = Html::element( 'link', [
                'rel' => 'apple-touch-icon',
                'href' => $appleTouchIconHref
            ] );
        }
 
        $faviconHref = $config->get( MainConfigNames::Favicon );
        # Browser look for those by default, unnessecary to set a link tag
        if ( $faviconHref !== false && $faviconHref !== '/favicon.ico' ) {
            $tags['favicon'] = Html::element( 'link', [
                'rel' => 'icon',
                'href' => $faviconHref
            ] );
        }
 
        # OpenSearch description link
        $tags['opensearch'] = Html::element( 'link', [
            'rel' => 'search',
            'type' => 'application/opensearchdescription+xml',
            'href' => wfScript( 'rest' ) . '/v1/search',
            'title' => $this->msg( 'opensearch-desc' )->inContentLanguage()->text(),
        ] );
 
        $services = MediaWikiServices::getInstance();
 
        # Real Simple Discovery link, provides auto-discovery information
        # for the MediaWiki API (and potentially additional custom API
        # support such as WordPress or Twitter-compatible APIs for a
        # blogging extension, etc)
        $tags['rsd'] = Html::element( 'link', [
            'rel' => 'EditURI',
            'type' => 'application/rsd+xml',
            // Output a protocol-relative URL here if $wgServer is protocol-relative.
            // Whether RSD accepts relative or protocol-relative URLs is completely
            // undocumented, though.
            'href' => (string)$services->getUrlUtils()->expand( wfAppendQuery(
                wfScript( 'api' ),
                [ 'action' => 'rsd' ] ),
                PROTO_RELATIVE
            ),
        ] );
 
        $tags = array_merge(
            $tags,
            $this->getHeadLinksCanonicalURLArray( $config ),
            $this->getHeadLinksAlternateURLsArray(),
            $this->getHeadLinksCopyrightArray( $config ),
            $this->getHeadLinksSyndicationArray( $config ),
        );
 
        // Allow extensions to add, remove and/or otherwise manipulate these links
        // If you want only to *add* <head> links, please use the addHeadItem()
        // (or addHeadItems() for multiple items) method instead.
        // This hook is provided as a last resort for extensions to modify these
        // links before the output is sent to client.
        $this->getHookRunner()->onOutputPageAfterGetHeadLinksArray( $tags, $this );
 
        return $tags;
    }
 
    private function getHeadLinksCanonicalURLArray( Config $config ) {
        $tags = [];
        $canonicalUrl = $this->mCanonicalUrl;
 
        if ( $config->get( MainConfigNames::EnableCanonicalServerLink ) ) {
            $query = [];
            $action = $this->getContext()->getActionName();
            $isCanonicalUrlAction = in_array( $action, [ 'history', 'info' ] );
            $services = MediaWikiServices::getInstance();
            $languageConverterFactory = $services->getLanguageConverterFactory();
            $isLangConversionDisabled = $languageConverterFactory->isConversionDisabled();
            $pageLang = $this->getTitle()->getPageLanguage();
            $pageLanguageConverter = $languageConverterFactory->getLanguageConverter( $pageLang );
            $urlVariant = $pageLanguageConverter->getURLVariant();
 
            if ( $canonicalUrl !== false ) {
                $canonicalUrl = (string)$services->getUrlUtils()->expand( $canonicalUrl, PROTO_CANONICAL );
            } elseif ( $this->isArticleRelated() ) {
                if ( $isCanonicalUrlAction ) {
                    $query['action'] = $action;
                } elseif ( !$isLangConversionDisabled && $urlVariant ) {
                    # T54429, T108443: Making canonical URL language-variant-aware.
                    $query['variant'] = $urlVariant;
                }
                $canonicalUrl = $this->getTitle()->getCanonicalURL( $query );
            } else {
                $reqUrl = $this->getRequest()->getRequestURL();
                $canonicalUrl = (string)$services->getUrlUtils()->expand( $reqUrl, PROTO_CANONICAL );
            }
        }
 
        if ( $canonicalUrl !== false ) {
            $tags['link-canonical'] = Html::element( 'link', [
                'rel' => 'canonical',
                'href' => $canonicalUrl
            ] );
        }
 
        return $tags;
    }
 
    private function getHeadLinksAlternateURLsArray() {
        $tags = [];
        $languageUrls = [];
        $action = $this->getContext()->getActionName();
        $isCanonicalUrlAction = in_array( $action, [ 'history', 'info' ] );
        $services = MediaWikiServices::getInstance();
        $languageConverterFactory = $services->getLanguageConverterFactory();
        $isLangConversionDisabled = $languageConverterFactory->isConversionDisabled();
        $pageLang = $this->getTitle()->getPageLanguage();
        $pageLanguageConverter = $languageConverterFactory->getLanguageConverter( $pageLang );
 
        # Language variants
        if (
            $this->isArticleRelated() &&
            !$isCanonicalUrlAction &&
            $pageLanguageConverter->hasVariants() &&
            !$isLangConversionDisabled
        ) {
            $variants = $pageLanguageConverter->getVariants();
            foreach ( $variants as $variant ) {
                $bcp47 = LanguageCode::bcp47( $variant );
                $languageUrls[$bcp47] = $this->getTitle()
                    ->getFullURL( [ 'variant' => $variant ], false, PROTO_CURRENT );
            }
        }
 
        # Alternate URLs for interlanguage links would be handeled in HTML body tag instead of
        #  head tag, see T326829.
 
        if ( $languageUrls ) {
            # Force the alternate URL of page language code to be self.
            # T123901, T305540, T108443: Override mixed-variant variant link in language variant links.
            $currentUrl = $this->getTitle()->getFullURL( [], false, PROTO_CURRENT );
            $pageLangCodeBcp47 = LanguageCode::bcp47( $pageLang->getCode() );
            $languageUrls[$pageLangCodeBcp47] = $currentUrl;
 
            ksort( $languageUrls );
 
            # Also add x-default link per https://support.google.com/webmasters/answer/189077?hl=en
            $languageUrls['x-default'] = $currentUrl;
 
            # Process all of language variants and interlanguage links
            foreach ( $languageUrls as $bcp47 => $languageUrl ) {
                $bcp47lowercase = strtolower( $bcp47 );
                $tags['link-alternate-language-' . $bcp47lowercase] = Html::element( 'link', [
                    'rel' => 'alternate',
                    'hreflang' => $bcp47,
                    'href' => $languageUrl,
                ] );
            }
        }
 
        return $tags;
    }
 
    private function getHeadLinksCopyrightArray( Config $config ) {
        $tags = [];
 
        if ( $this->copyrightUrl !== null ) {
            $copyright = $this->copyrightUrl;
        } else {
            $copyright = '';
            if ( $config->get( MainConfigNames::RightsPage ) ) {
                $copy = Title::newFromText( $config->get( MainConfigNames::RightsPage ) );
 
                if ( $copy ) {
                    $copyright = $copy->getLocalURL();
                }
            }
 
            if ( !$copyright && $config->get( MainConfigNames::RightsUrl ) ) {
                $copyright = $config->get( MainConfigNames::RightsUrl );
            }
        }
 
        if ( $copyright ) {
            $tags['copyright'] = Html::element( 'link', [
                'rel' => 'license',
                'href' => $copyright
            ] );
        }
 
        return $tags;
    }
 
    private function getHeadLinksSyndicationArray( Config $config ) {
        if ( !$config->get( MainConfigNames::Feed ) ) {
            return [];
        }
 
        $tags = [];
        $feedLinks = [];
 
        foreach ( $this->getSyndicationLinks() as $format => $link ) {
            # Use the page name for the title.  In principle, this could
            # lead to issues with having the same name for different feeds
            # corresponding to the same page, but we can't avoid that at
            # this low a level.
 
            $feedLinks[] = $this->feedLink(
                $format,
                $link,
                # Used messages: 'page-rss-feed' and 'page-atom-feed' (for an easier grep)
                $this->msg(
                    "page-{$format}-feed", $this->getTitle()->getPrefixedText()
                )->text()
            );
        }
 
        # Recent changes feed should appear on every page (except recentchanges,
        # that would be redundant). Put it after the per-page feed to avoid
        # changing existing behavior. It's still available, probably via a
        # menu in your browser. Some sites might have a different feed they'd
        # like to promote instead of the RC feed (maybe like a "Recent New Articles"
        # or "Breaking news" one). For this, we see if $wgOverrideSiteFeed is defined.
        # If so, use it instead.
        $sitename = $config->get( MainConfigNames::Sitename );
        $overrideSiteFeed = $config->get( MainConfigNames::OverrideSiteFeed );
        if ( $overrideSiteFeed ) {
            foreach ( $overrideSiteFeed as $type => $feedUrl ) {
                // Note, this->feedLink escapes the url.
                $feedLinks[] = $this->feedLink(
                    $type,
                    $feedUrl,
                    $this->msg( "site-{$type}-feed", $sitename )->text()
                );
            }
        } elseif ( !$this->getTitle()->isSpecial( 'Recentchanges' ) ) {
            $rctitle = SpecialPage::getTitleFor( 'Recentchanges' );
            foreach ( $this->getAdvertisedFeedTypes() as $format ) {
                $feedLinks[] = $this->feedLink(
                    $format,
                    $rctitle->getLocalURL( [ 'feed' => $format ] ),
                    # For grep: 'site-rss-feed', 'site-atom-feed'
                    $this->msg( "site-{$format}-feed", $sitename )->text()
                );
            }
        }
 
        # Allow extensions to change the list pf feeds. This hook is primarily for changing,
        # manipulating or removing existing feed tags. If you want to add new feeds, you should
        # use OutputPage::addFeedLink() instead.
        $this->getHookRunner()->onAfterBuildFeedLinks( $feedLinks );
 
        $tags += $feedLinks;
 
        return $tags;
    }
 
    private function feedLink( $type, $url, $text ) {
        return Html::element( 'link', [
            'rel' => 'alternate',
            'type' => "application/$type+xml",
            'title' => $text,
            'href' => $url ]
        );
    }
 
    public function addStyle( $style, $media = '', $condition = '', $dir = '' ) {
        $options = [];
        if ( $media ) {
            $options['media'] = $media;
        }
        if ( $condition ) {
            $options['condition'] = $condition;
        }
        if ( $dir ) {
            $options['dir'] = $dir;
        }
        $this->styles[$style] = $options;
    }
 
    public function addInlineStyle( $style_css, $flip = 'noflip' ) {
        if ( $flip === 'flip' && $this->getLanguage()->isRTL() ) {
            # If wanted, and the interface is right-to-left, flip the CSS
            $style_css = CSSJanus::transform( $style_css, true, false );
        }
        $this->mInlineStyles .= Html::inlineStyle( $style_css );
    }
 
    protected function buildExemptModules() {
        $chunks = [];
 
        // Requirements:
        // - Within modules provided by the software (core, skin, extensions),
        //   styles from skin stylesheets should be overridden by styles
        //   from modules dynamically loaded with JavaScript.
        // - Styles from site-specific, private, and user modules should override
        //   both of the above.
        //
        // The effective order for stylesheets must thus be:
        // 1. Page style modules, formatted server-side by RL\ClientHtml.
        // 2. Dynamically-loaded styles, inserted client-side by mw.loader.
        // 3. Styles that are site-specific, private or from the user, formatted
        //    server-side by this function.
        //
        // The 'ResourceLoaderDynamicStyles' marker helps JavaScript know where
        // point #2 is.
 
        // Add legacy styles added through addStyle()/addInlineStyle() here
        $chunks[] = implode( '', $this->buildCssLinksArray() ) . $this->mInlineStyles;
 
        // Things that go after the ResourceLoaderDynamicStyles marker
        $append = [];
        $separateReq = [ 'site.styles', 'user.styles' ];
        foreach ( $this->rlExemptStyleModules as $moduleNames ) {
            if ( $moduleNames ) {
                $append[] = $this->makeResourceLoaderLink(
                    array_diff( $moduleNames, $separateReq ),
                    RL\Module::TYPE_STYLES
                );
 
                foreach ( array_intersect( $moduleNames, $separateReq ) as $name ) {
                    // These require their own dedicated request in order to support "@import"
                    // syntax, which is incompatible with concatenation. (T147667, T37562)
                    $append[] = $this->makeResourceLoaderLink( $name,
                        RL\Module::TYPE_STYLES
                    );
                }
            }
        }
        if ( $append ) {
            $chunks[] = Html::element(
                'meta',
                [ 'name' => 'ResourceLoaderDynamicStyles', 'content' => '' ]
            );
            $chunks = array_merge( $chunks, $append );
        }
 
        return self::combineWrappedStrings( $chunks );
    }
 
    public function buildCssLinksArray() {
        $links = [];
 
        foreach ( $this->styles as $file => $options ) {
            $link = $this->styleLink( $file, $options );
            if ( $link ) {
                $links[$file] = $link;
            }
        }
        return $links;
    }
 
    protected function styleLink( $style, array $options ) {
        if ( isset( $options['dir'] ) && $this->getLanguage()->getDir() != $options['dir'] ) {
            return '';
        }
 
        if ( isset( $options['media'] ) ) {
            $media = self::transformCssMedia( $options['media'] );
            if ( $media === null ) {
                return '';
            }
        } else {
            $media = 'all';
        }
 
        if ( str_starts_with( $style, '/' ) ||
            str_starts_with( $style, 'http:' ) ||
            str_starts_with( $style, 'https:' )
        ) {
            $url = $style;
        } else {
            $config = $this->getConfig();
            // Append file hash as query parameter
            $url = self::transformResourcePath(
                $config,
                $config->get( MainConfigNames::StylePath ) . '/' . $style
            );
        }
 
        $link = Html::linkedStyle( $url, $media );
 
        if ( isset( $options['condition'] ) ) {
            $condition = htmlspecialchars( $options['condition'] );
            $link = "<!--[if $condition]>$link<![endif]-->";
        }
        return $link;
    }
 
    public static function transformResourcePath( Config $config, $path ) {
        $localDir = $config->get( MainConfigNames::BaseDirectory );
        $remotePathPrefix = $config->get( MainConfigNames::ResourceBasePath );
        if ( $remotePathPrefix === '' ) {
            // The configured base path is required to be empty string for
            // wikis in the domain root
            $remotePath = '/';
        } else {
            $remotePath = $remotePathPrefix;
        }
        if ( !str_starts_with( $path, $remotePath ) || str_starts_with( $path, '//' ) ) {
            // - Path is outside wgResourceBasePath, ignore.
            // - Path is protocol-relative. Fixes T155310. Not supported by RelPath lib.
            return $path;
        }
        // For files in resources, extensions/ or skins/, ResourceBasePath is preferred here.
        // For other misc files in $IP, we'll fallback to that as well. There is, however, a fourth
        // supported dir/path pair in the configuration (wgUploadDirectory, wgUploadPath)
        // which is not expected to be in wgResourceBasePath on CDNs. (T155146)
        $uploadPath = $config->get( MainConfigNames::UploadPath );
        if ( strpos( $path, $uploadPath ) === 0 ) {
            $localDir = $config->get( MainConfigNames::UploadDirectory );
            $remotePathPrefix = $remotePath = $uploadPath;
        }
 
        $path = RelPath::getRelativePath( $path, $remotePath );
        return self::transformFilePath( $remotePathPrefix, $localDir, $path );
    }
 
    public static function transformFilePath( $remotePathPrefix, $localPath, $file ) {
        // This MUST match the equivalent logic in CSSMin::remapOne()
        $localFile = "$localPath/$file";
        $url = "$remotePathPrefix/$file";
        if ( is_file( $localFile ) ) {
            $hash = md5_file( $localFile );
            if ( $hash === false ) {
                wfLogWarning( __METHOD__ . ": Failed to hash $localFile" );
                $hash = '';
            }
            $url .= '?' . substr( $hash, 0, 5 );
        }
        return $url;
    }
 
    public static function transformCssMedia( $media ) {
        global $wgRequest;
 
        if ( $wgRequest->getBool( 'printable' ) ) {
            // When browsing with printable=yes, apply "print" media styles
            // as if they are screen styles (no media, media="").
            if ( $media === 'print' ) {
                return '';
            }
 
            // https://www.w3.org/TR/css3-mediaqueries/#syntax
            //
            // This regex will not attempt to understand a comma-separated media_query_list
            // Example supported values for $media:
            //
            //     'screen', 'only screen', 'screen and (min-width: 982px)' ),
            //
            // Example NOT supported value for $media:
            //
            //     '3d-glasses, screen, print and resolution > 90dpi'
            //
            // If it's a "printable" request, we disable all screen stylesheets.
            $screenMediaQueryRegex = '/^(?:only\s+)?screen\b/i';
            if ( preg_match( $screenMediaQueryRegex, $media ) === 1 ) {
                return null;
            }
        }
 
        return $media;
    }
 
    public function addWikiMsg( $name, ...$args ) {
        $this->addWikiMsgArray( $name, $args );
    }
 
    public function addWikiMsgArray( $name, $args ) {
        $this->addHTML( $this->msg( $name, $args )->parseAsBlock() );
    }
 
    public function wrapWikiMsg( $wrap, ...$msgSpecs ) {
        $s = $wrap;
        foreach ( $msgSpecs as $n => $spec ) {
            if ( is_array( $spec ) ) {
                $args = $spec;
                $name = array_shift( $args );
            } else {
                $args = [];
                $name = $spec;
            }
            $s = str_replace( '$' . ( $n + 1 ), $this->msg( $name, $args )->plain(), $s );
        }
        $this->addWikiTextAsInterface( $s );
    }
 
    public function isTOCEnabled() {
        return $this->mEnableTOC;
    }
 
    public static function setupOOUI( $skinName = null, $dir = null ) {
        if ( !self::$oouiSetupDone ) {
            self::$oouiSetupDone = true;
            $context = RequestContext::getMain();
            $skinName = $context->getSkinName();
            $dir = $context->getLanguage()->getDir();
            $themes = RL\OOUIFileModule::getSkinThemeMap();
            $theme = $themes[$skinName] ?? $themes['default'];
            // For example, 'OOUI\WikimediaUITheme'.
            $themeClass = "OOUI\\{$theme}Theme";
            Theme::setSingleton( new $themeClass() );
            Element::setDefaultDir( $dir );
        }
    }
 
    public static function resetOOUI() {
        if ( self::$oouiSetupDone ) {
            self::$oouiSetupDone = false;
            self::setupOOUI();
        }
    }
 
    public function enableOOUI() {
        self::setupOOUI();
        $this->addModuleStyles( [
            'oojs-ui-core.styles',
            'oojs-ui.styles.indicators',
            'mediawiki.widgets.styles',
            'oojs-ui-core.icons',
        ] );
    }
 
    public function getCSP() {
        return $this->CSP;
    }
 
    public function setCspOutputMode( string $mode ): void {
        $this->cspOutputMode = $mode;
    }
 
    public function tailElement( $skin ) {
        $tail = [
            MWDebug::getDebugHTML( $skin ),
            $this->getBottomScripts(),
            MWDebug::getHTMLDebugLog(),
            Html::closeElement( 'body' ),
            Html::closeElement( 'html' ),
        ];
 
        return WrappedStringList::join( "\n", $tail );
    }
}
 
class_alias( OutputPage::class, 'OutputPage' );