Parser.php

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<?php
use MediaWiki\BadFileLookup;
use MediaWiki\Cache\CacheKeyHelper;
use MediaWiki\Config\ServiceOptions;
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\Http\HttpRequestFactory;
use MediaWiki\Languages\LanguageConverterFactory;
use MediaWiki\Languages\LanguageNameUtils;
use MediaWiki\Linker\LinkRenderer;
use MediaWiki\Linker\LinkRendererFactory;
use MediaWiki\Linker\LinkTarget;
use MediaWiki\MediaWikiServices;
use MediaWiki\Page\PageIdentity;
use MediaWiki\Page\PageReference;
use MediaWiki\Parser\ParserOutputFlags;
use MediaWiki\Revision\RevisionAccessException;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\Revision\SlotRecord;
use MediaWiki\SpecialPage\SpecialPageFactory;
use MediaWiki\Tidy\TidyDriverBase;
use MediaWiki\User\UserFactory;
use MediaWiki\User\UserIdentity;
use MediaWiki\User\UserOptionsLookup;
use Psr\Log\LoggerInterface;
use Wikimedia\IPUtils;
use Wikimedia\ScopedCallback;
 
class Parser {
 
    # Flags for Parser::setFunctionHook
    public const SFH_NO_HASH = 1;
    public const SFH_OBJECT_ARGS = 2;
 
    # Constants needed for external link processing
    # Everything except bracket, space, or control characters
    # \p{Zs} is unicode 'separator, space' category. It covers the space 0x20
    # as well as U+3000 is IDEOGRAPHIC SPACE for T21052
    # \x{FFFD} is the Unicode replacement character, which the HTML5 spec
    # uses to replace invalid HTML characters.
    public const EXT_LINK_URL_CLASS = '[^][<>"\\x00-\\x20\\x7F\p{Zs}\x{FFFD}]';
    # Simplified expression to match an IPv4 or IPv6 address, or
    # at least one character of a host name (embeds EXT_LINK_URL_CLASS)
    // phpcs:ignore Generic.Files.LineLength
    private const EXT_LINK_ADDR = '(?:[0-9.]+|\\[(?i:[0-9a-f:.]+)\\]|[^][<>"\\x00-\\x20\\x7F\p{Zs}\x{FFFD}])';
    # RegExp to make image URLs (embeds IPv6 part of EXT_LINK_ADDR)
    // phpcs:ignore Generic.Files.LineLength
    private const EXT_IMAGE_REGEX = '/^(http:\/\/|https:\/\/)((?:\\[(?i:[0-9a-f:.]+)\\])?[^][<>"\\x00-\\x20\\x7F\p{Zs}\x{FFFD}]+)
        \\/([A-Za-z0-9_.,~%\\-+&;#*?!=()@\\x80-\\xFF]+)\\.((?i)gif|png|jpg|jpeg)$/Sxu';
 
    # Regular expression for a non-newline space
    private const SPACE_NOT_NL = '(?:\t|&nbsp;|&\#0*160;|&\#[Xx]0*[Aa]0;|\p{Zs})';
 
    public const PTD_FOR_INCLUSION = Preprocessor::DOM_FOR_INCLUSION;
 
    # Allowed values for $this->mOutputType
    # Parameter to startExternalParse().
    public const OT_HTML = 1; # like parse()
    public const OT_WIKI = 2; # like preSaveTransform()
    public const OT_PREPROCESS = 3; # like preprocess()
    public const OT_MSG = 3;
    # like extractSections() - portions of the original are returned unchanged.
    public const OT_PLAIN = 4;
 
    public const MARKER_SUFFIX = "-QINU`\"'\x7f";
    public const MARKER_PREFIX = "\x7f'\"`UNIQ-";
 
    public const TOC_START = '<mw:toc>';
 
    public const TOC_END = '</mw:toc>';
 
    public const TOC_PLACEHOLDER = '<mw:tocplace></mw:tocplace>';
 
    # Persistent:
    private $mTagHooks = [];
    private $mFunctionHooks = [];
    private $mFunctionSynonyms = [ 0 => [], 1 => [] ];
    private $mStripList = [];
    private $mVarCache = [];
    private $mImageParams = [];
    private $mImageParamsMagicArray = [];
    public $mMarkerIndex = 0;
    public $mFirstCall = false;
 
    # Initialised by initializeVariables()
 
    private $mVariables;
 
    private $mSubstWords;
 
    # Initialised in constructor
    private $mExtLinkBracketedRegex, $mUrlProtocols;
 
    # Initialized in constructor
 
    private $mPreprocessor;
 
    # Cleared with clearState():
 
    private $mOutput;
    private $mAutonumber;
 
    private $mStripState;
 
    private $mLinkHolders;
 
    public $mLinkID;
    public $mIncludeSizes;
    public $mPPNodeCount;
    public $mGeneratedPPNodeCount;
    public $mHighestExpansionDepth;
    private $mDefaultSort;
    private $mTplRedirCache;
    public $mHeadings;
    public $mDoubleUnderscores;
    public $mExpensiveFunctionCount; # number of expensive parser function calls
    public $mShowToc;
    private $mForceTocPosition;
    private $mTplDomCache;
 
    private $mUser;
 
    # Temporary
    # These are variables reset at least once per parse regardless of $clearState
 
    public $mOptions;
 
    public $mTitle;        # Title context, used for self-link rendering and similar things
    private $mOutputType;   # Output type, one of the OT_xxx constants
    public $ot;            # Shortcut alias, see setOutputType()
    public $mRevisionId;   # ID to display in {{REVISIONID}} tags
 
    public $mRevisionTimestamp; # The timestamp of the specified revision ID
    public $mRevisionUser; # User to display in {{REVISIONUSER}} tag
    public $mRevisionSize; # Size to display in {{REVISIONSIZE}} variable
    public $mInputSize = false; # For {{PAGESIZE}} on current page.
 
    private $mRevisionRecordObject;
 
    private $mLangLinkLanguages;
 
    private $currentRevisionCache;
 
    public $mInParse = false;
 
    private $mProfiler;
 
    private $mLinkRenderer;
 
    private $magicWordFactory;
 
    private $contLang;
 
    private $languageConverterFactory;
 
    private $factory;
 
    private $specialPageFactory;
 
    private $titleFormatter;
 
    private $svcOptions;
 
    private $linkRendererFactory;
 
    private $nsInfo;
 
    private $logger;
 
    private $badFileLookup;
 
    private $hookContainer;
 
    private $hookRunner;
 
    private $tidy;
 
    private $userOptionsLookup;
 
    private $userFactory;
 
    private $httpRequestFactory;
 
    private $trackingCategories;
 
    public const CONSTRUCTOR_OPTIONS = [
        // See documentation for the corresponding config options
        'ArticlePath',
        'EnableScaryTranscluding',
        'ExtraInterlanguageLinkPrefixes',
        'FragmentMode',
        'MaxSigChars',
        'MaxTocLevel',
        'MiserMode',
        'ScriptPath',
        'Server',
        'ServerName',
        'ShowHostnames',
        'SignatureValidation',
        'Sitename',
        'StylePath',
        'TranscludeCacheExpiry',
        'PreprocessorCacheThreshold',
    ];
 
    public function __construct(
        ServiceOptions $svcOptions,
        MagicWordFactory $magicWordFactory,
        Language $contLang,
        ParserFactory $factory,
        string $urlProtocols,
        SpecialPageFactory $spFactory,
        LinkRendererFactory $linkRendererFactory,
        NamespaceInfo $nsInfo,
        LoggerInterface $logger,
        BadFileLookup $badFileLookup,
        LanguageConverterFactory $languageConverterFactory,
        HookContainer $hookContainer,
        TidyDriverBase $tidy,
        WANObjectCache $wanCache,
        UserOptionsLookup $userOptionsLookup,
        UserFactory $userFactory,
        TitleFormatter $titleFormatter,
        HttpRequestFactory $httpRequestFactory,
        TrackingCategories $trackingCategories
    ) {
        if ( ParserFactory::$inParserFactory === 0 ) {
            // Direct construction of Parser was deprecated in 1.34 and
            // removed in 1.36; use a ParserFactory instead.
            throw new MWException( 'Direct construction of Parser not allowed' );
        }
        $svcOptions->assertRequiredOptions( self::CONSTRUCTOR_OPTIONS );
        $this->svcOptions = $svcOptions;
 
        $this->mUrlProtocols = $urlProtocols;
        $this->mExtLinkBracketedRegex = '/\[(((?i)' . $this->mUrlProtocols . ')' .
            self::EXT_LINK_ADDR .
            self::EXT_LINK_URL_CLASS . '*)\p{Zs}*([^\]\\x00-\\x08\\x0a-\\x1F\\x{FFFD}]*?)\]/Su';
 
        $this->magicWordFactory = $magicWordFactory;
 
        $this->contLang = $contLang;
 
        $this->factory = $factory;
        $this->specialPageFactory = $spFactory;
        $this->linkRendererFactory = $linkRendererFactory;
        $this->nsInfo = $nsInfo;
        $this->logger = $logger;
        $this->badFileLookup = $badFileLookup;
 
        $this->languageConverterFactory = $languageConverterFactory;
 
        $this->hookContainer = $hookContainer;
        $this->hookRunner = new HookRunner( $hookContainer );
 
        $this->tidy = $tidy;
 
        $this->mPreprocessor = new Preprocessor_Hash(
            $this,
            $wanCache,
            [
                'cacheThreshold' => $svcOptions->get( 'PreprocessorCacheThreshold' ),
                'disableLangConversion' => $languageConverterFactory->isConversionDisabled(),
            ]
        );
 
        $this->userOptionsLookup = $userOptionsLookup;
        $this->userFactory = $userFactory;
        $this->titleFormatter = $titleFormatter;
        $this->httpRequestFactory = $httpRequestFactory;
        $this->trackingCategories = $trackingCategories;
 
        // These steps used to be done in "::firstCallInit()"
        // (if you're chasing a reference from some old code)
        CoreParserFunctions::register( $this );
        CoreTagHooks::register( $this );
        $this->initializeVariables();
 
        $this->hookRunner->onParserFirstCallInit( $this );
    }
 
    public function __destruct() {
        if ( isset( $this->mLinkHolders ) ) {
            // @phan-suppress-next-line PhanTypeObjectUnsetDeclaredProperty
            unset( $this->mLinkHolders );
        }
        // @phan-suppress-next-line PhanTypeSuspiciousNonTraversableForeach
        foreach ( $this as $name => $value ) {
            unset( $this->$name );
        }
    }
 
    public function __clone() {
        $this->mInParse = false;
 
        // T58226: When you create a reference "to" an object field, that
        // makes the object field itself be a reference too (until the other
        // reference goes out of scope). When cloning, any field that's a
        // reference is copied as a reference in the new object. Both of these
        // are defined PHP5 behaviors, as inconvenient as it is for us when old
        // hooks from PHP4 days are passing fields by reference.
        foreach ( [ 'mStripState', 'mVarCache' ] as $k ) {
            // Make a non-reference copy of the field, then rebind the field to
            // reference the new copy.
            $tmp = $this->$k;
            $this->$k =& $tmp;
            unset( $tmp );
        }
 
        $this->mPreprocessor = clone $this->mPreprocessor;
        $this->mPreprocessor->resetParser( $this );
 
        $this->hookRunner->onParserCloned( $this );
    }
 
    public function firstCallInit() {
        /*
         * This method should be hard-deprecated once remaining calls are
         * removed; it no longer does anything.
         */
    }
 
    public function clearState() {
        $this->resetOutput();
        $this->mAutonumber = 0;
        $this->mLinkHolders = new LinkHolderArray(
            $this,
            $this->getContentLanguageConverter(),
            $this->getHookContainer()
        );
        $this->mLinkID = 0;
        $this->mRevisionTimestamp = null;
        $this->mRevisionId = null;
        $this->mRevisionUser = null;
        $this->mRevisionSize = null;
        $this->mRevisionRecordObject = null;
        $this->mVarCache = [];
        $this->mUser = null;
        $this->mLangLinkLanguages = [];
        $this->currentRevisionCache = null;
 
        $this->mStripState = new StripState( $this );
 
        # Clear these on every parse, T6549
        $this->mTplRedirCache = [];
        $this->mTplDomCache = [];
 
        $this->mShowToc = true;
        $this->mForceTocPosition = false;
        $this->mIncludeSizes = [
            'post-expand' => 0,
            'arg' => 0,
        ];
        $this->mPPNodeCount = 0;
        $this->mGeneratedPPNodeCount = 0;
        $this->mHighestExpansionDepth = 0;
        $this->mDefaultSort = false;
        $this->mHeadings = [];
        $this->mDoubleUnderscores = [];
        $this->mExpensiveFunctionCount = 0;
 
        $this->mProfiler = new SectionProfiler();
 
        $this->hookRunner->onParserClearState( $this );
    }
 
    public function resetOutput() {
        $this->mOutput = new ParserOutput;
        $this->mOptions->registerWatcher( [ $this->mOutput, 'recordOption' ] );
    }
 
    public function parse(
        $text, PageReference $page, ParserOptions $options,
        $linestart = true, $clearState = true, $revid = null
    ) {
        if ( $clearState ) {
            // We use U+007F DELETE to construct strip markers, so we have to make
            // sure that this character does not occur in the input text.
            $text = strtr( $text, "\x7f", "?" );
            $magicScopeVariable = $this->lock();
        }
        // Strip U+0000 NULL (T159174)
        $text = str_replace( "\000", '', $text );
 
        $this->startParse( $page, $options, self::OT_HTML, $clearState );
 
        $this->currentRevisionCache = null;
        $this->mInputSize = strlen( $text );
        $this->mOutput->resetParseStartTime();
 
        $oldRevisionId = $this->mRevisionId;
        $oldRevisionRecordObject = $this->mRevisionRecordObject;
        $oldRevisionTimestamp = $this->mRevisionTimestamp;
        $oldRevisionUser = $this->mRevisionUser;
        $oldRevisionSize = $this->mRevisionSize;
        if ( $revid !== null ) {
            $this->mRevisionId = $revid;
            $this->mRevisionRecordObject = null;
            $this->mRevisionTimestamp = null;
            $this->mRevisionUser = null;
            $this->mRevisionSize = null;
        }
 
        $text = $this->internalParse( $text );
        $this->hookRunner->onParserAfterParse( $this, $text, $this->mStripState );
 
        $text = $this->internalParseHalfParsed( $text, true, $linestart );
 
        if ( !$options->getDisableTitleConversion()
            && !isset( $this->mDoubleUnderscores['nocontentconvert'] )
            && !isset( $this->mDoubleUnderscores['notitleconvert'] )
            && $this->mOutput->getDisplayTitle() === false
        ) {
            $titleText = $this->getTargetLanguageConverter()->getConvRuleTitle();
            if ( $titleText === false ) {
                $titleText = $this->getTargetLanguageConverter()->convertTitle( $page );
            }
            $this->mOutput->setTitleText(
                htmlspecialchars( $titleText, ENT_NOQUOTES )
            );
        }
 
        # Compute runtime adaptive expiry if set
        $this->mOutput->finalizeAdaptiveCacheExpiry();
 
        # Warn if too many heavyweight parser functions were used
        if ( $this->mExpensiveFunctionCount > $this->mOptions->getExpensiveParserFunctionLimit() ) {
            $this->limitationWarn( 'expensive-parserfunction',
                $this->mExpensiveFunctionCount,
                $this->mOptions->getExpensiveParserFunctionLimit()
            );
        }
 
        # Information on limits, for the benefit of users who try to skirt them
        if ( MediaWikiServices::getInstance()->getMainConfig()->get( 'EnableParserLimitReporting' ) ) {
            $this->makeLimitReport();
        }
 
        # Wrap non-interface parser output in a <div> so it can be targeted
        # with CSS (T37247)
        $class = $this->mOptions->getWrapOutputClass();
        if ( $class !== false && !$this->mOptions->getInterfaceMessage() ) {
            $this->mOutput->addWrapperDivClass( $class );
        }
 
        $this->mOutput->setText( $text );
 
        $this->mRevisionId = $oldRevisionId;
        $this->mRevisionRecordObject = $oldRevisionRecordObject;
        $this->mRevisionTimestamp = $oldRevisionTimestamp;
        $this->mRevisionUser = $oldRevisionUser;
        $this->mRevisionSize = $oldRevisionSize;
        $this->mInputSize = false;
        $this->currentRevisionCache = null;
 
        return $this->mOutput;
    }
 
    protected function makeLimitReport() {
        $maxIncludeSize = $this->mOptions->getMaxIncludeSize();
 
        $cpuTime = $this->mOutput->getTimeSinceStart( 'cpu' );
        if ( $cpuTime !== null ) {
            $this->mOutput->setLimitReportData( 'limitreport-cputime',
                sprintf( "%.3f", $cpuTime )
            );
        }
 
        $wallTime = $this->mOutput->getTimeSinceStart( 'wall' );
        $this->mOutput->setLimitReportData( 'limitreport-walltime',
            sprintf( "%.3f", $wallTime )
        );
 
        $this->mOutput->setLimitReportData( 'limitreport-ppvisitednodes',
            [ $this->mPPNodeCount, $this->mOptions->getMaxPPNodeCount() ]
        );
        $this->mOutput->setLimitReportData( 'limitreport-postexpandincludesize',
            [ $this->mIncludeSizes['post-expand'], $maxIncludeSize ]
        );
        $this->mOutput->setLimitReportData( 'limitreport-templateargumentsize',
            [ $this->mIncludeSizes['arg'], $maxIncludeSize ]
        );
        $this->mOutput->setLimitReportData( 'limitreport-expansiondepth',
            [ $this->mHighestExpansionDepth, $this->mOptions->getMaxPPExpandDepth() ]
        );
        $this->mOutput->setLimitReportData( 'limitreport-expensivefunctioncount',
            [ $this->mExpensiveFunctionCount, $this->mOptions->getExpensiveParserFunctionLimit() ]
        );
 
        foreach ( $this->mStripState->getLimitReport() as list( $key, $value ) ) {
            $this->mOutput->setLimitReportData( $key, $value );
        }
 
        $this->hookRunner->onParserLimitReportPrepare( $this, $this->mOutput );
 
        // Add on template profiling data in human/machine readable way
        $dataByFunc = $this->mProfiler->getFunctionStats();
        uasort( $dataByFunc, static function ( $a, $b ) {
            return $b['real'] <=> $a['real']; // descending order
        } );
        $profileReport = [];
        foreach ( array_slice( $dataByFunc, 0, 10 ) as $item ) {
            $profileReport[] = sprintf( "%6.2f%% %8.3f %6d %s",
                $item['%real'], $item['real'], $item['calls'],
                htmlspecialchars( $item['name'] ) );
        }
 
        $this->mOutput->setLimitReportData( 'limitreport-timingprofile', $profileReport );
 
        // Add other cache related metadata
        if ( $this->svcOptions->get( 'ShowHostnames' ) ) {
            $this->mOutput->setLimitReportData( 'cachereport-origin', wfHostname() );
        }
        $this->mOutput->setLimitReportData( 'cachereport-timestamp',
            $this->mOutput->getCacheTime() );
        $this->mOutput->setLimitReportData( 'cachereport-ttl',
            $this->mOutput->getCacheExpiry() );
        $this->mOutput->setLimitReportData( 'cachereport-transientcontent',
            $this->mOutput->hasReducedExpiry() );
    }
 
    public function recursiveTagParse( $text, $frame = false ) {
        $text = $this->internalParse( $text, false, $frame );
        return $text;
    }
 
    public function recursiveTagParseFully( $text, $frame = false ) {
        $text = $this->recursiveTagParse( $text, $frame );
        $text = $this->internalParseHalfParsed( $text, false );
        return $text;
    }
 
    public function parseExtensionTagAsTopLevelDoc( $text ) {
        $text = $this->recursiveTagParse( $text );
        $this->hookRunner->onParserAfterParse( $this, $text, $this->mStripState );
        $text = $this->internalParseHalfParsed( $text, true );
        return $text;
    }
 
    public function preprocess(
        $text,
        ?PageReference $page,
        ParserOptions $options,
        $revid = null,
        $frame = false
    ) {
        $magicScopeVariable = $this->lock();
        $this->startParse( $page, $options, self::OT_PREPROCESS, true );
        if ( $revid !== null ) {
            $this->mRevisionId = $revid;
        }
        $this->hookRunner->onParserBeforePreprocess( $this, $text, $this->mStripState );
        $text = $this->replaceVariables( $text, $frame );
        $text = $this->mStripState->unstripBoth( $text );
        return $text;
    }
 
    public function recursivePreprocess( $text, $frame = false ) {
        $text = $this->replaceVariables( $text, $frame );
        $text = $this->mStripState->unstripBoth( $text );
        return $text;
    }
 
    public function getPreloadText( $text, PageReference $page, ParserOptions $options, $params = [] ) {
        $msg = new RawMessage( $text );
        $text = $msg->params( $params )->plain();
 
        # Parser (re)initialisation
        $magicScopeVariable = $this->lock();
        $this->startParse( $page, $options, self::OT_PLAIN, true );
 
        $flags = PPFrame::NO_ARGS | PPFrame::NO_TEMPLATES;
        $dom = $this->preprocessToDom( $text, Preprocessor::DOM_FOR_INCLUSION );
        $text = $this->getPreprocessor()->newFrame()->expand( $dom, $flags );
        $text = $this->mStripState->unstripBoth( $text );
        return $text;
    }
 
    public function setUser( ?UserIdentity $user ) {
        $this->mUser = $user;
    }
 
    public function setTitle( Title $t = null ) {
        $this->setPage( $t );
    }
 
    public function getTitle(): Title {
        if ( !$this->mTitle ) {
            $this->mTitle = Title::makeTitle( NS_SPECIAL, 'Badtitle/Parser' );
        }
        return $this->mTitle;
    }
 
    public function setPage( ?PageReference $t = null ) {
        if ( !$t ) {
            $t = Title::makeTitle( NS_SPECIAL, 'Badtitle/Parser' );
        } else {
            // For now (early 1.37 alpha), always convert to Title, so we don't have to do it over
            // and over again in other methods. Eventually, we will no longer need to have a Title
            // instance internally.
            $t = Title::castFromPageReference( $t );
        }
 
        if ( $t->hasFragment() ) {
            # Strip the fragment to avoid various odd effects
            $this->mTitle = $t->createFragmentTarget( '' );
        } else {
            $this->mTitle = $t;
        }
    }
 
    public function getPage(): ?PageReference {
        return $this->mTitle;
    }
 
    public function getOutputType(): int {
        return $this->mOutputType;
    }
 
    public function setOutputType( $ot ): void {
        $this->mOutputType = $ot;
        # Shortcut alias
        $this->ot = [
            'html' => $ot == self::OT_HTML,
            'wiki' => $ot == self::OT_WIKI,
            'pre' => $ot == self::OT_PREPROCESS,
            'plain' => $ot == self::OT_PLAIN,
        ];
    }
 
    public function OutputType( $x = null ) {
        wfDeprecated( __METHOD__, '1.35' );
        return wfSetVar( $this->mOutputType, $x );
    }
 
    public function getOutput() {
        return $this->mOutput;
    }
 
    public function getOptions() {
        return $this->mOptions;
    }
 
    public function setOptions( ParserOptions $options ): void {
        $this->mOptions = $options;
    }
 
    public function Options( $x = null ) {
        wfDeprecated( __METHOD__, '1.35' );
        return wfSetVar( $this->mOptions, $x );
    }
 
    public function nextLinkID() {
        return $this->mLinkID++;
    }
 
    public function setLinkID( $id ) {
        $this->mLinkID = $id;
    }
 
    public function getFunctionLang() {
        return $this->getTargetLanguage();
    }
 
    public function getTargetLanguage() {
        $target = $this->mOptions->getTargetLanguage();
 
        if ( $target !== null ) {
            return $target;
        } elseif ( $this->mOptions->getInterfaceMessage() ) {
            return $this->mOptions->getUserLangObj();
        }
 
        return $this->getTitle()->getPageLanguage();
    }
 
    public function getUserIdentity(): UserIdentity {
        return $this->mUser ?? $this->getOptions()->getUserIdentity();
    }
 
    public function getPreprocessor() {
        return $this->mPreprocessor;
    }
 
    public function getLinkRenderer() {
        // XXX We make the LinkRenderer with current options and then cache it forever
        if ( !$this->mLinkRenderer ) {
            $this->mLinkRenderer = $this->linkRendererFactory->create();
        }
 
        return $this->mLinkRenderer;
    }
 
    public function getMagicWordFactory() {
        return $this->magicWordFactory;
    }
 
    public function getContentLanguage() {
        return $this->contLang;
    }
 
    public function getBadFileLookup() {
        return $this->badFileLookup;
    }
 
    public static function extractTagsAndParams( array $elements, $text, &$matches ) {
        static $n = 1;
        $stripped = '';
        $matches = [];
 
        $taglist = implode( '|', $elements );
        $start = "/<($taglist)(\\s+[^>]*?|\\s*?)(\/?>)|<(!--)/i";
 
        while ( $text != '' ) {
            $p = preg_split( $start, $text, 2, PREG_SPLIT_DELIM_CAPTURE );
            $stripped .= $p[0];
            if ( count( $p ) < 5 ) {
                break;
            }
            if ( count( $p ) > 5 ) {
                # comment
                $element = $p[4];
                $attributes = '';
                $close = '';
                $inside = $p[5];
            } else {
                # tag
                list( , $element, $attributes, $close, $inside ) = $p;
            }
 
            $marker = self::MARKER_PREFIX . "-$element-" . sprintf( '%08X', $n++ ) . self::MARKER_SUFFIX;
            $stripped .= $marker;
 
            if ( $close === '/>' ) {
                # Empty element tag, <tag />
                $content = null;
                $text = $inside;
                $tail = null;
            } else {
                if ( $element === '!--' ) {
                    $end = '/(-->)/';
                } else {
                    $end = "/(<\\/$element\\s*>)/i";
                }
                $q = preg_split( $end, $inside, 2, PREG_SPLIT_DELIM_CAPTURE );
                $content = $q[0];
                if ( count( $q ) < 3 ) {
                    # No end tag -- let it run out to the end of the text.
                    $tail = '';
                    $text = '';
                } else {
                    list( , $tail, $text ) = $q;
                }
            }
 
            $matches[$marker] = [ $element,
                $content,
                Sanitizer::decodeTagAttributes( $attributes ),
                "<$element$attributes$close$content$tail" ];
        }
        return $stripped;
    }
 
    public function getStripList() {
        return $this->mStripList;
    }
 
    public function getStripState() {
        return $this->mStripState;
    }
 
    public function insertStripItem( $text ) {
        $marker = self::MARKER_PREFIX . "-item-{$this->mMarkerIndex}-" . self::MARKER_SUFFIX;
        $this->mMarkerIndex++;
        $this->mStripState->addGeneral( $marker, $text );
        return $marker;
    }
 
    private function handleTables( $text ) {
        $lines = StringUtils::explode( "\n", $text );
        $out = '';
        $td_history = []; # Is currently a td tag open?
        $last_tag_history = []; # Save history of last lag activated (td, th or caption)
        $tr_history = []; # Is currently a tr tag open?
        $tr_attributes = []; # history of tr attributes
        $has_opened_tr = []; # Did this table open a <tr> element?
        $indent_level = 0; # indent level of the table
 
        foreach ( $lines as $outLine ) {
            $line = trim( $outLine );
 
            if ( $line === '' ) { # empty line, go to next line
                $out .= $outLine . "\n";
                continue;
            }
 
            $first_character = $line[0];
            $first_two = substr( $line, 0, 2 );
            $matches = [];
 
            if ( preg_match( '/^(:*)\s*\{\|(.*)$/', $line, $matches ) ) {
                # First check if we are starting a new table
                $indent_level = strlen( $matches[1] );
 
                $attributes = $this->mStripState->unstripBoth( $matches[2] );
                $attributes = Sanitizer::fixTagAttributes( $attributes, 'table' );
 
                $outLine = str_repeat( '<dl><dd>', $indent_level ) . "<table{$attributes}>";
                array_push( $td_history, false );
                array_push( $last_tag_history, '' );
                array_push( $tr_history, false );
                array_push( $tr_attributes, '' );
                array_push( $has_opened_tr, false );
            } elseif ( count( $td_history ) == 0 ) {
                # Don't do any of the following
                $out .= $outLine . "\n";
                continue;
            } elseif ( $first_two === '|}' ) {
                # We are ending a table
                $line = '</table>' . substr( $line, 2 );
                $last_tag = array_pop( $last_tag_history );
 
                if ( !array_pop( $has_opened_tr ) ) {
                    $line = "<tr><td></td></tr>{$line}";
                }
 
                if ( array_pop( $tr_history ) ) {
                    $line = "</tr>{$line}";
                }
 
                if ( array_pop( $td_history ) ) {
                    $line = "</{$last_tag}>{$line}";
                }
                array_pop( $tr_attributes );
                if ( $indent_level > 0 ) {
                    $outLine = rtrim( $line ) . str_repeat( '</dd></dl>', $indent_level );
                } else {
                    $outLine = $line;
                }
            } elseif ( $first_two === '|-' ) {
                # Now we have a table row
                $line = preg_replace( '#^\|-+#', '', $line );
 
                # Whats after the tag is now only attributes
                $attributes = $this->mStripState->unstripBoth( $line );
                $attributes = Sanitizer::fixTagAttributes( $attributes, 'tr' );
                array_pop( $tr_attributes );
                array_push( $tr_attributes, $attributes );
 
                $line = '';
                $last_tag = array_pop( $last_tag_history );
                array_pop( $has_opened_tr );
                array_push( $has_opened_tr, true );
 
                if ( array_pop( $tr_history ) ) {
                    $line = '</tr>';
                }
 
                if ( array_pop( $td_history ) ) {
                    $line = "</{$last_tag}>{$line}";
                }
 
                $outLine = $line;
                array_push( $tr_history, false );
                array_push( $td_history, false );
                array_push( $last_tag_history, '' );
            } elseif ( $first_character === '|'
                || $first_character === '!'
                || $first_two === '|+'
            ) {
                # This might be cell elements, td, th or captions
                if ( $first_two === '|+' ) {
                    $first_character = '+';
                    $line = substr( $line, 2 );
                } else {
                    $line = substr( $line, 1 );
                }
 
                // Implies both are valid for table headings.
                if ( $first_character === '!' ) {
                    $line = StringUtils::replaceMarkup( '!!', '||', $line );
                }
 
                # Split up multiple cells on the same line.
                # FIXME : This can result in improper nesting of tags processed
                # by earlier parser steps.
                $cells = explode( '||', $line );
 
                $outLine = '';
 
                # Loop through each table cell
                foreach ( $cells as $cell ) {
                    $previous = '';
                    if ( $first_character !== '+' ) {
                        $tr_after = array_pop( $tr_attributes );
                        if ( !array_pop( $tr_history ) ) {
                            $previous = "<tr{$tr_after}>\n";
                        }
                        array_push( $tr_history, true );
                        array_push( $tr_attributes, '' );
                        array_pop( $has_opened_tr );
                        array_push( $has_opened_tr, true );
                    }
 
                    $last_tag = array_pop( $last_tag_history );
 
                    if ( array_pop( $td_history ) ) {
                        $previous = "</{$last_tag}>\n{$previous}";
                    }
 
                    if ( $first_character === '|' ) {
                        $last_tag = 'td';
                    } elseif ( $first_character === '!' ) {
                        $last_tag = 'th';
                    } elseif ( $first_character === '+' ) {
                        $last_tag = 'caption';
                    } else {
                        $last_tag = '';
                    }
 
                    array_push( $last_tag_history, $last_tag );
 
                    # A cell could contain both parameters and data
                    $cell_data = explode( '|', $cell, 2 );
 
                    # T2553: Note that a '|' inside an invalid link should not
                    # be mistaken as delimiting cell parameters
                    # Bug T153140: Neither should language converter markup.
                    if ( preg_match( '/\[\[|-\{/', $cell_data[0] ) === 1 ) {
                        $cell = "{$previous}<{$last_tag}>" . trim( $cell );
                    } elseif ( count( $cell_data ) == 1 ) {
                        // Whitespace in cells is trimmed
                        $cell = "{$previous}<{$last_tag}>" . trim( $cell_data[0] );
                    } else {
                        $attributes = $this->mStripState->unstripBoth( $cell_data[0] );
                        $attributes = Sanitizer::fixTagAttributes( $attributes, $last_tag );
                        // Whitespace in cells is trimmed
                        $cell = "{$previous}<{$last_tag}{$attributes}>" . trim( $cell_data[1] );
                    }
 
                    $outLine .= $cell;
                    array_push( $td_history, true );
                }
            }
            $out .= $outLine . "\n";
        }
 
        # Closing open td, tr && table
        while ( count( $td_history ) > 0 ) {
            if ( array_pop( $td_history ) ) {
                $out .= "</td>\n";
            }
            if ( array_pop( $tr_history ) ) {
                $out .= "</tr>\n";
            }
            if ( !array_pop( $has_opened_tr ) ) {
                $out .= "<tr><td></td></tr>\n";
            }
 
            $out .= "</table>\n";
        }
 
        # Remove trailing line-ending (b/c)
        if ( substr( $out, -1 ) === "\n" ) {
            $out = substr( $out, 0, -1 );
        }
 
        # special case: don't return empty table
        if ( $out === "<table>\n<tr><td></td></tr>\n</table>" ) {
            $out = '';
        }
 
        return $out;
    }
 
    public function internalParse( $text, $isMain = true, $frame = false ) {
        $origText = $text;
 
        # Hook to suspend the parser in this state
        if ( !$this->hookRunner->onParserBeforeInternalParse( $this, $text, $this->mStripState ) ) {
            return $text;
        }
 
        # if $frame is provided, then use $frame for replacing any variables
        if ( $frame ) {
            # use frame depth to infer how include/noinclude tags should be handled
            # depth=0 means this is the top-level document; otherwise it's an included document
            if ( !$frame->depth ) {
                $flag = 0;
            } else {
                $flag = Preprocessor::DOM_FOR_INCLUSION;
            }
            $dom = $this->preprocessToDom( $text, $flag );
            $text = $frame->expand( $dom );
        } else {
            # if $frame is not provided, then use old-style replaceVariables
            $text = $this->replaceVariables( $text );
        }
 
        $this->hookRunner->onInternalParseBeforeSanitize( $this, $text, $this->mStripState );
        $text = Sanitizer::removeHTMLtags(
            $text,
            // Callback from the Sanitizer for expanding items found in
            // HTML attribute values, so they can be safely tested and escaped.
            function ( &$text, $frame = false ) {
                $text = $this->replaceVariables( $text, $frame );
                $text = $this->mStripState->unstripBoth( $text );
            },
            false,
            [],
            []
        );
        $this->hookRunner->onInternalParseBeforeLinks( $this, $text, $this->mStripState );
 
        # Tables need to come after variable replacement for things to work
        # properly; putting them before other transformations should keep
        # exciting things like link expansions from showing up in surprising
        # places.
        $text = $this->handleTables( $text );
 
        $text = preg_replace( '/(^|\n)-----*/', '\\1<hr />', $text );
 
        $text = $this->handleDoubleUnderscore( $text );
 
        $text = $this->handleHeadings( $text );
        $text = $this->handleInternalLinks( $text );
        $text = $this->handleAllQuotes( $text );
        $text = $this->handleExternalLinks( $text );
 
        # handleInternalLinks may sometimes leave behind
        # absolute URLs, which have to be masked to hide them from handleExternalLinks
        $text = str_replace( self::MARKER_PREFIX . 'NOPARSE', '', $text );
 
        $text = $this->handleMagicLinks( $text );
        $text = $this->finalizeHeadings( $text, $origText, $isMain );
 
        return $text;
    }
 
    public function getTargetLanguageConverter(): ILanguageConverter {
        return $this->languageConverterFactory->getLanguageConverter(
            $this->getTargetLanguage()
        );
    }
 
    private function getContentLanguageConverter(): ILanguageConverter {
        return $this->languageConverterFactory->getLanguageConverter(
            $this->getContentLanguage()
        );
    }
 
    protected function getHookContainer() {
        return $this->hookContainer;
    }
 
    protected function getHookRunner() {
        return $this->hookRunner;
    }
 
    private function internalParseHalfParsed( $text, $isMain = true, $linestart = true ) {
        $text = $this->mStripState->unstripGeneral( $text );
 
        $text = BlockLevelPass::doBlockLevels( $text, $linestart );
 
        $this->replaceLinkHoldersPrivate( $text );
 
        if ( !( $this->mOptions->getDisableContentConversion()
            || isset( $this->mDoubleUnderscores['nocontentconvert'] ) )
            && !$this->mOptions->getInterfaceMessage()
        ) {
            # The position of the convert() call should not be changed. it
            # assumes that the links are all replaced and the only thing left
            # is the <nowiki> mark.
            $text = $this->getTargetLanguageConverter()->convert( $text );
        }
 
        $text = $this->mStripState->unstripNoWiki( $text );
 
        $text = $this->mStripState->unstripGeneral( $text );
 
        $text = $this->tidy->tidy( $text, [ Sanitizer::class, 'armorFrenchSpaces' ] );
 
        if ( $isMain ) {
            $this->hookRunner->onParserAfterTidy( $this, $text );
        }
 
        return $text;
    }
 
    private function handleMagicLinks( $text ) {
        $prots = wfUrlProtocolsWithoutProtRel();
        $urlChar = self::EXT_LINK_URL_CLASS;
        $addr = self::EXT_LINK_ADDR;
        $space = self::SPACE_NOT_NL; #  non-newline space
        $spdash = "(?:-|$space)"; # a dash or a non-newline space
        $spaces = "$space++"; # possessive match of 1 or more spaces
        $text = preg_replace_callback(
            '!(?:                        # Start cases
                (<a[ \t\r\n>].*?</a>) |    # m[1]: Skip link text
                (<.*?>) |                  # m[2]: Skip stuff inside HTML elements' . "
                (\b                        # m[3]: Free external links
                    (?i:$prots)
                    ($addr$urlChar*)         # m[4]: Post-protocol path
                ) |
                \b(?:RFC|PMID) $spaces     # m[5]: RFC or PMID, capture number
                    ([0-9]+)\b |
                \bISBN $spaces (           # m[6]: ISBN, capture number
                    (?: 97[89] $spdash? )?   #  optional 13-digit ISBN prefix
                    (?: [0-9]  $spdash? ){9} #  9 digits with opt. delimiters
                    [0-9Xx]                  #  check digit
                )\b
            )!xu",
            [ $this, 'magicLinkCallback' ],
            $text
        );
        return $text;
    }
 
    private function magicLinkCallback( array $m ) {
        if ( isset( $m[1] ) && $m[1] !== '' ) {
            # Skip anchor
            return $m[0];
        } elseif ( isset( $m[2] ) && $m[2] !== '' ) {
            # Skip HTML element
            return $m[0];
        } elseif ( isset( $m[3] ) && $m[3] !== '' ) {
            # Free external link
            return $this->makeFreeExternalLink( $m[0], strlen( $m[4] ) );
        } elseif ( isset( $m[5] ) && $m[5] !== '' ) {
            # RFC or PMID
            if ( substr( $m[0], 0, 3 ) === 'RFC' ) {
                if ( !$this->mOptions->getMagicRFCLinks() ) {
                    return $m[0];
                }
                $keyword = 'RFC';
                $urlmsg = 'rfcurl';
                $cssClass = 'mw-magiclink-rfc';
                $trackingCat = 'magiclink-tracking-rfc';
                $id = $m[5];
            } elseif ( substr( $m[0], 0, 4 ) === 'PMID' ) {
                if ( !$this->mOptions->getMagicPMIDLinks() ) {
                    return $m[0];
                }
                $keyword = 'PMID';
                $urlmsg = 'pubmedurl';
                $cssClass = 'mw-magiclink-pmid';
                $trackingCat = 'magiclink-tracking-pmid';
                $id = $m[5];
            } else {
                // Should never happen
                throw new MWException( __METHOD__ . ': unrecognised match type "' .
                    substr( $m[0], 0, 20 ) . '"' );
            }
            $url = wfMessage( $urlmsg, $id )->inContentLanguage()->text();
            $this->addTrackingCategory( $trackingCat );
            return Linker::makeExternalLink(
                $url,
                "{$keyword} {$id}",
                true,
                $cssClass,
                [],
                $this->getTitle()
            );
        } elseif ( isset( $m[6] ) && $m[6] !== ''
            && $this->mOptions->getMagicISBNLinks()
        ) {
            # ISBN
            $isbn = $m[6];
            $space = self::SPACE_NOT_NL; #  non-newline space
            $isbn = preg_replace( "/$space/", ' ', $isbn );
            $num = strtr( $isbn, [
                '-' => '',
                ' ' => '',
                'x' => 'X',
            ] );
            $this->addTrackingCategory( 'magiclink-tracking-isbn' );
            return $this->getLinkRenderer()->makeKnownLink(
                SpecialPage::getTitleFor( 'Booksources', $num ),
                "ISBN $isbn",
                [
                    'class' => 'internal mw-magiclink-isbn',
                    'title' => false // suppress title attribute
                ]
            );
        } else {
            return $m[0];
        }
    }
 
    private function makeFreeExternalLink( $url, $numPostProto ) {
        $trail = '';
 
        # The characters '<' and '>' (which were escaped by
        # removeHTMLtags()) should not be included in
        # URLs, per RFC 2396.
        # Make &nbsp; terminate a URL as well (bug T84937)
        $m2 = [];
        if ( preg_match(
            '/&(lt|gt|nbsp|#x0*(3[CcEe]|[Aa]0)|#0*(60|62|160));/',
            $url,
            $m2,
            PREG_OFFSET_CAPTURE
        ) ) {
            $trail = substr( $url, $m2[0][1] ) . $trail;
            $url = substr( $url, 0, $m2[0][1] );
        }
 
        # Move trailing punctuation to $trail
        $sep = ',;\.:!?';
        # If there is no left bracket, then consider right brackets fair game too
        if ( strpos( $url, '(' ) === false ) {
            $sep .= ')';
        }
 
        $urlRev = strrev( $url );
        $numSepChars = strspn( $urlRev, $sep );
        # Don't break a trailing HTML entity by moving the ; into $trail
        # This is in hot code, so use substr_compare to avoid having to
        # create a new string object for the comparison
        if ( $numSepChars && substr_compare( $url, ";", -$numSepChars, 1 ) === 0 ) {
            # more optimization: instead of running preg_match with a $
            # anchor, which can be slow, do the match on the reversed
            # string starting at the desired offset.
            # un-reversed regexp is: /&([a-z]+|#x[\da-f]+|#\d+)$/i
            if ( preg_match( '/\G([a-z]+|[\da-f]+x#|\d+#)&/i', $urlRev, $m2, 0, $numSepChars ) ) {
                $numSepChars--;
            }
        }
        if ( $numSepChars ) {
            $trail = substr( $url, -$numSepChars ) . $trail;
            $url = substr( $url, 0, -$numSepChars );
        }
 
        # Verify that we still have a real URL after trail removal, and
        # not just lone protocol
        if ( strlen( $trail ) >= $numPostProto ) {
            return $url . $trail;
        }
 
        $url = Sanitizer::cleanUrl( $url );
 
        # Is this an external image?
        $text = $this->maybeMakeExternalImage( $url );
        if ( $text === false ) {
            # Not an image, make a link
            $text = Linker::makeExternalLink(
                $url,
                $this->getTargetLanguageConverter()->markNoConversion( $url ),
                true,
                'free',
                $this->getExternalLinkAttribs( $url ),
                $this->getTitle()
            );
            # Register it in the output object...
            $this->mOutput->addExternalLink( $url );
        }
        return $text . $trail;
    }
 
    private function handleHeadings( $text ) {
        for ( $i = 6; $i >= 1; --$i ) {
            $h = str_repeat( '=', $i );
            // Trim non-newline whitespace from headings
            // Using \s* will break for: "==\n===\n" and parse as <h2>=</h2>
            $text = preg_replace( "/^(?:$h)[ \\t]*(.+?)[ \\t]*(?:$h)\\s*$/m", "<h$i>\\1</h$i>", $text );
        }
        return $text;
    }
 
    private function handleAllQuotes( $text ) {
        $outtext = '';
        $lines = StringUtils::explode( "\n", $text );
        foreach ( $lines as $line ) {
            $outtext .= $this->doQuotes( $line ) . "\n";
        }
        $outtext = substr( $outtext, 0, -1 );
        return $outtext;
    }
 
    public function doQuotes( $text ) {
        $arr = preg_split( "/(''+)/", $text, -1, PREG_SPLIT_DELIM_CAPTURE );
        $countarr = count( $arr );
        if ( $countarr == 1 ) {
            return $text;
        }
 
        // First, do some preliminary work. This may shift some apostrophes from
        // being mark-up to being text. It also counts the number of occurrences
        // of bold and italics mark-ups.
        $numbold = 0;
        $numitalics = 0;
        for ( $i = 1; $i < $countarr; $i += 2 ) {
            $thislen = strlen( $arr[$i] );
            // If there are ever four apostrophes, assume the first is supposed to
            // be text, and the remaining three constitute mark-up for bold text.
            // (T15227: ''''foo'''' turns into ' ''' foo ' ''')
            if ( $thislen == 4 ) {
                $arr[$i - 1] .= "'";
                $arr[$i] = "'''";
                $thislen = 3;
            } elseif ( $thislen > 5 ) {
                // If there are more than 5 apostrophes in a row, assume they're all
                // text except for the last 5.
                // (T15227: ''''''foo'''''' turns into ' ''''' foo ' ''''')
                $arr[$i - 1] .= str_repeat( "'", $thislen - 5 );
                $arr[$i] = "'''''";
                $thislen = 5;
            }
            // Count the number of occurrences of bold and italics mark-ups.
            if ( $thislen == 2 ) {
                $numitalics++;
            } elseif ( $thislen == 3 ) {
                $numbold++;
            } elseif ( $thislen == 5 ) {
                $numitalics++;
                $numbold++;
            }
        }
 
        // If there is an odd number of both bold and italics, it is likely
        // that one of the bold ones was meant to be an apostrophe followed
        // by italics. Which one we cannot know for certain, but it is more
        // likely to be one that has a single-letter word before it.
        if ( ( $numbold % 2 == 1 ) && ( $numitalics % 2 == 1 ) ) {
            $firstsingleletterword = -1;
            $firstmultiletterword = -1;
            $firstspace = -1;
            for ( $i = 1; $i < $countarr; $i += 2 ) {
                if ( strlen( $arr[$i] ) == 3 ) {
                    $x1 = substr( $arr[$i - 1], -1 );
                    $x2 = substr( $arr[$i - 1], -2, 1 );
                    if ( $x1 === ' ' ) {
                        if ( $firstspace == -1 ) {
                            $firstspace = $i;
                        }
                    } elseif ( $x2 === ' ' ) {
                        $firstsingleletterword = $i;
                        // if $firstsingleletterword is set, we don't
                        // look at the other options, so we can bail early.
                        break;
                    } elseif ( $firstmultiletterword == -1 ) {
                        $firstmultiletterword = $i;
                    }
                }
            }
 
            // If there is a single-letter word, use it!
            if ( $firstsingleletterword > -1 ) {
                $arr[$firstsingleletterword] = "''";
                $arr[$firstsingleletterword - 1] .= "'";
            } elseif ( $firstmultiletterword > -1 ) {
                // If not, but there's a multi-letter word, use that one.
                $arr[$firstmultiletterword] = "''";
                $arr[$firstmultiletterword - 1] .= "'";
            } elseif ( $firstspace > -1 ) {
                // ... otherwise use the first one that has neither.
                // (notice that it is possible for all three to be -1 if, for example,
                // there is only one pentuple-apostrophe in the line)
                $arr[$firstspace] = "''";
                $arr[$firstspace - 1] .= "'";
            }
        }
 
        // Now let's actually convert our apostrophic mush to HTML!
        $output = '';
        $buffer = '';
        $state = '';
        $i = 0;
        foreach ( $arr as $r ) {
            if ( ( $i % 2 ) == 0 ) {
                if ( $state === 'both' ) {
                    $buffer .= $r;
                } else {
                    $output .= $r;
                }
            } else {
                $thislen = strlen( $r );
                if ( $thislen == 2 ) {
                    // two quotes - open or close italics
                    if ( $state === 'i' ) {
                        $output .= '</i>';
                        $state = '';
                    } elseif ( $state === 'bi' ) {
                        $output .= '</i>';
                        $state = 'b';
                    } elseif ( $state === 'ib' ) {
                        $output .= '</b></i><b>';
                        $state = 'b';
                    } elseif ( $state === 'both' ) {
                        $output .= '<b><i>' . $buffer . '</i>';
                        $state = 'b';
                    } else { // $state can be 'b' or ''
                        $output .= '<i>';
                        $state .= 'i';
                    }
                } elseif ( $thislen == 3 ) {
                    // three quotes - open or close bold
                    if ( $state === 'b' ) {
                        $output .= '</b>';
                        $state = '';
                    } elseif ( $state === 'bi' ) {
                        $output .= '</i></b><i>';
                        $state = 'i';
                    } elseif ( $state === 'ib' ) {
                        $output .= '</b>';
                        $state = 'i';
                    } elseif ( $state === 'both' ) {
                        $output .= '<i><b>' . $buffer . '</b>';
                        $state = 'i';
                    } else { // $state can be 'i' or ''
                        $output .= '<b>';
                        $state .= 'b';
                    }
                } elseif ( $thislen == 5 ) {
                    // five quotes - open or close both separately
                    if ( $state === 'b' ) {
                        $output .= '</b><i>';
                        $state = 'i';
                    } elseif ( $state === 'i' ) {
                        $output .= '</i><b>';
                        $state = 'b';
                    } elseif ( $state === 'bi' ) {
                        $output .= '</i></b>';
                        $state = '';
                    } elseif ( $state === 'ib' ) {
                        $output .= '</b></i>';
                        $state = '';
                    } elseif ( $state === 'both' ) {
                        $output .= '<i><b>' . $buffer . '</b></i>';
                        $state = '';
                    } else { // ($state == '')
                        $buffer = '';
                        $state = 'both';
                    }
                }
            }
            $i++;
        }
        // Now close all remaining tags.  Notice that the order is important.
        if ( $state === 'b' || $state === 'ib' ) {
            $output .= '</b>';
        }
        if ( $state === 'i' || $state === 'bi' || $state === 'ib' ) {
            $output .= '</i>';
        }
        if ( $state === 'bi' ) {
            $output .= '</b>';
        }
        // There might be lonely ''''', so make sure we have a buffer
        if ( $state === 'both' && $buffer ) {
            $output .= '<b><i>' . $buffer . '</i></b>';
        }
        return $output;
    }
 
    private function handleExternalLinks( $text ) {
        $bits = preg_split( $this->mExtLinkBracketedRegex, $text, -1, PREG_SPLIT_DELIM_CAPTURE );
        // @phan-suppress-next-line PhanTypeComparisonFromArray See phan issue #3161
        if ( $bits === false ) {
            throw new MWException( "PCRE needs to be compiled with "
                . "--enable-unicode-properties in order for MediaWiki to function" );
        }
        $s = array_shift( $bits );
 
        $i = 0;
        while ( $i < count( $bits ) ) {
            $url = $bits[$i++];
            $i++; // protocol
            $text = $bits[$i++];
            $trail = $bits[$i++];
 
            # The characters '<' and '>' (which were escaped by
            # removeHTMLtags()) should not be included in
            # URLs, per RFC 2396.
            $m2 = [];
            if ( preg_match( '/&(lt|gt);/', $url, $m2, PREG_OFFSET_CAPTURE ) ) {
                $text = substr( $url, $m2[0][1] ) . ' ' . $text;
                $url = substr( $url, 0, $m2[0][1] );
            }
 
            # If the link text is an image URL, replace it with an <img> tag
            # This happened by accident in the original parser, but some people used it extensively
            $img = $this->maybeMakeExternalImage( $text );
            if ( $img !== false ) {
                $text = $img;
            }
 
            $dtrail = '';
 
            # Set linktype for CSS
            $linktype = 'text';
 
            # No link text, e.g. [http://domain.tld/some.link]
            if ( $text == '' ) {
                # Autonumber
                $langObj = $this->getTargetLanguage();
                $text = '[' . $langObj->formatNum( ++$this->mAutonumber ) . ']';
                $linktype = 'autonumber';
            } else {
                # Have link text, e.g. [http://domain.tld/some.link text]s
                # Check for trail
                list( $dtrail, $trail ) = Linker::splitTrail( $trail );
            }
 
            // Excluding protocol-relative URLs may avoid many false positives.
            if ( preg_match( '/^(?:' . wfUrlProtocolsWithoutProtRel() . ')/', $text ) ) {
                $text = $this->getTargetLanguageConverter()->markNoConversion( $text );
            }
 
            $url = Sanitizer::cleanUrl( $url );
 
            # Use the encoded URL
            # This means that users can paste URLs directly into the text
            # Funny characters like ö aren't valid in URLs anyway
            # This was changed in August 2004
            // @phan-suppress-next-line SecurityCheck-XSS,SecurityCheck-DoubleEscaped using false for escape is valid
            $s .= Linker::makeExternalLink( $url, $text, false, $linktype,
                $this->getExternalLinkAttribs( $url ), $this->getTitle() ) . $dtrail . $trail;
 
            # Register link in the output object.
            $this->mOutput->addExternalLink( $url );
        }
 
        return $s;
    }
 
    public static function getExternalLinkRel( $url = false, LinkTarget $title = null ) {
        $mainConfig = MediaWikiServices::getInstance()->getMainConfig();
        $noFollowLinks = $mainConfig->get( 'NoFollowLinks' );
        $noFollowNsExceptions = $mainConfig->get( 'NoFollowNsExceptions' );
        $noFollowDomainExceptions = $mainConfig->get( 'NoFollowDomainExceptions' );
        $ns = $title ? $title->getNamespace() : false;
        if ( $noFollowLinks && !in_array( $ns, $noFollowNsExceptions )
            && !wfMatchesDomainList( $url, $noFollowDomainExceptions )
        ) {
            return 'nofollow';
        }
        return null;
    }
 
    public function getExternalLinkAttribs( $url ) {
        $attribs = [];
        $rel = self::getExternalLinkRel( $url, $this->getTitle() );
 
        $target = $this->mOptions->getExternalLinkTarget();
        if ( $target ) {
            $attribs['target'] = $target;
            if ( !in_array( $target, [ '_self', '_parent', '_top' ] ) ) {
                // T133507. New windows can navigate parent cross-origin.
                // Including noreferrer due to lacking browser
                // support of noopener. Eventually noreferrer should be removed.
                if ( $rel !== '' ) {
                    $rel .= ' ';
                }
                $rel .= 'noreferrer noopener';
            }
        }
        $attribs['rel'] = $rel;
        return $attribs;
    }
 
    public static function normalizeLinkUrl( $url ) {
        # Test for RFC 3986 IPv6 syntax
        $scheme = '[a-z][a-z0-9+.-]*:';
        $userinfo = '(?:[a-z0-9\-._~!$&\'()*+,;=:]|%[0-9a-f]{2})*';
        $ipv6Host = '\\[((?:[0-9a-f:]|%3[0-A]|%[46][1-6])+)\\]';
        if ( preg_match( "<^(?:{$scheme})?//(?:{$userinfo}@)?{$ipv6Host}(?:[:/?#].*|)$>i", $url, $m ) &&
            IPUtils::isValid( rawurldecode( $m[1] ) )
        ) {
            $isIPv6 = rawurldecode( $m[1] );
        } else {
            $isIPv6 = false;
        }
 
        # Make sure unsafe characters are encoded
        $url = preg_replace_callback(
            '/[\x00-\x20"<>\[\\\\\]^`{|}\x7F-\xFF]/',
            static function ( $m ) {
                return rawurlencode( $m[0] );
            },
            $url
        );
 
        $ret = '';
        $end = strlen( $url );
 
        # Fragment part - 'fragment'
        $start = strpos( $url, '#' );
        if ( $start !== false && $start < $end ) {
            $ret = self::normalizeUrlComponent(
                substr( $url, $start, $end - $start ), '"#%<>[\]^`{|}' ) . $ret;
            $end = $start;
        }
 
        # Query part - 'query' minus &=+;
        $start = strpos( $url, '?' );
        if ( $start !== false && $start < $end ) {
            $ret = self::normalizeUrlComponent(
                substr( $url, $start, $end - $start ), '"#%<>[\]^`{|}&=+;' ) . $ret;
            $end = $start;
        }
 
        # Scheme and path part - 'pchar'
        # (we assume no userinfo or encoded colons in the host)
        $ret = self::normalizeUrlComponent(
            substr( $url, 0, $end ), '"#%<>[\]^`{|}/?' ) . $ret;
 
        # Fix IPv6 syntax
        if ( $isIPv6 !== false ) {
            $ipv6Host = "%5B({$isIPv6})%5D";
            $ret = preg_replace(
                "<^((?:{$scheme})?//(?:{$userinfo}@)?){$ipv6Host}(?=[:/?#]|$)>i",
                "$1[$2]",
                $ret
            );
        }
 
        return $ret;
    }
 
    private static function normalizeUrlComponent( $component, $unsafe ) {
        $callback = static function ( $matches ) use ( $unsafe ) {
            $char = urldecode( $matches[0] );
            $ord = ord( $char );
            if ( $ord > 32 && $ord < 127 && strpos( $unsafe, $char ) === false ) {
                # Unescape it
                return $char;
            } else {
                # Leave it escaped, but use uppercase for a-f
                return strtoupper( $matches[0] );
            }
        };
        return preg_replace_callback( '/%[0-9A-Fa-f]{2}/', $callback, $component );
    }
 
    private function maybeMakeExternalImage( $url ) {
        $imagesfrom = $this->mOptions->getAllowExternalImagesFrom();
        $imagesexception = !empty( $imagesfrom );
        $text = false;
        # $imagesfrom could be either a single string or an array of strings, parse out the latter
        if ( $imagesexception && is_array( $imagesfrom ) ) {
            $imagematch = false;
            foreach ( $imagesfrom as $match ) {
                if ( strpos( $url, $match ) === 0 ) {
                    $imagematch = true;
                    break;
                }
            }
        } elseif ( $imagesexception ) {
            $imagematch = ( strpos( $url, $imagesfrom ) === 0 );
        } else {
            $imagematch = false;
        }
 
        if ( $this->mOptions->getAllowExternalImages()
            || ( $imagesexception && $imagematch )
        ) {
            if ( preg_match( self::EXT_IMAGE_REGEX, $url ) ) {
                # Image found
                $text = Linker::makeExternalImage( $url );
            }
        }
        if ( !$text && $this->mOptions->getEnableImageWhitelist()
            && preg_match( self::EXT_IMAGE_REGEX, $url )
        ) {
            $whitelist = explode(
                "\n",
                wfMessage( 'external_image_whitelist' )->inContentLanguage()->text()
            );
 
            foreach ( $whitelist as $entry ) {
                # Sanitize the regex fragment, make it case-insensitive, ignore blank entries/comments
                if ( strpos( $entry, '#' ) === 0 || $entry === '' ) {
                    continue;
                }
                // @phan-suppress-next-line SecurityCheck-ReDoS preg_quote is not wanted here
                if ( preg_match( '/' . str_replace( '/', '\\/', $entry ) . '/i', $url ) ) {
                    # Image matches a whitelist entry
                    $text = Linker::makeExternalImage( $url );
                    break;
                }
            }
        }
        return $text;
    }
 
    private function handleInternalLinks( $text ) {
        $this->mLinkHolders->merge( $this->handleInternalLinks2( $text ) );
        return $text;
    }
 
    private function handleInternalLinks2( &$s ) {
        static $tc = false, $e1, $e1_img;
        # the % is needed to support urlencoded titles as well
        if ( !$tc ) {
            $tc = Title::legalChars() . '#%';
            # Match a link having the form [[namespace:link|alternate]]trail
            $e1 = "/^([{$tc}]+)(?:\\|(.+?))?]](.*)\$/sD";
            # Match cases where there is no "]]", which might still be images
            $e1_img = "/^([{$tc}]+)\\|(.*)\$/sD";
        }
 
        $holders = new LinkHolderArray(
            $this,
            $this->getContentLanguageConverter(),
            $this->getHookContainer() );
 
        # split the entire text string on occurrences of [[
        $a = StringUtils::explode( '[[', ' ' . $s );
        # get the first element (all text up to first [[), and remove the space we added
        $s = $a->current();
        $a->next();
        $line = $a->current(); # Workaround for broken ArrayIterator::next() that returns "void"
        $s = substr( $s, 1 );
 
        $nottalk = !$this->getTitle()->isTalkPage();
 
        $useLinkPrefixExtension = $this->getTargetLanguage()->linkPrefixExtension();
        $e2 = null;
        if ( $useLinkPrefixExtension ) {
            # Match the end of a line for a word that's not followed by whitespace,
            # e.g. in the case of 'The Arab al[[Razi]]', 'al' will be matched
            $charset = $this->contLang->linkPrefixCharset();
            $e2 = "/^((?>.*[^$charset]|))(.+)$/sDu";
            $m = [];
            if ( preg_match( $e2, $s, $m ) ) {
                $first_prefix = $m[2];
            } else {
                $first_prefix = false;
            }
        } else {
            $prefix = '';
        }
 
        # Some namespaces don't allow subpages
        $useSubpages = $this->nsInfo->hasSubpages(
            $this->getTitle()->getNamespace()
        );
 
        # Loop for each link
        for ( ; $line !== false && $line !== null; $a->next(), $line = $a->current() ) {
            # Check for excessive memory usage
            if ( $holders->isBig() ) {
                # Too big
                # Do the existence check, replace the link holders and clear the array
                $holders->replace( $s );
                $holders->clear();
            }
 
            if ( $useLinkPrefixExtension ) {
                if ( preg_match( $e2, $s, $m ) ) {
                    list( , $s, $prefix ) = $m;
                } else {
                    $prefix = '';
                }
                # first link
                if ( $first_prefix ) {
                    $prefix = $first_prefix;
                    $first_prefix = false;
                }
            }
 
            $might_be_img = false;
 
            if ( preg_match( $e1, $line, $m ) ) { # page with normal text or alt
                $text = $m[2];
                # If we get a ] at the beginning of $m[3] that means we have a link that's something like:
                # [[Image:Foo.jpg|[http://example.com desc]]] <- having three ] in a row fucks up,
                # the real problem is with the $e1 regex
                # See T1500.
                # Still some problems for cases where the ] is meant to be outside punctuation,
                # and no image is in sight. See T4095.
                if ( $text !== ''
                    && substr( $m[3], 0, 1 ) === ']'
                    && strpos( $text, '[' ) !== false
                ) {
                    $text .= ']'; # so that handleExternalLinks($text) works later
                    $m[3] = substr( $m[3], 1 );
                }
                # fix up urlencoded title texts
                if ( strpos( $m[1], '%' ) !== false ) {
                    # Should anchors '#' also be rejected?
                    $m[1] = str_replace( [ '<', '>' ], [ '&lt;', '&gt;' ], rawurldecode( $m[1] ) );
                }
                $trail = $m[3];
            } elseif ( preg_match( $e1_img, $line, $m ) ) {
                # Invalid, but might be an image with a link in its caption
                $might_be_img = true;
                $text = $m[2];
                if ( strpos( $m[1], '%' ) !== false ) {
                    $m[1] = str_replace( [ '<', '>' ], [ '&lt;', '&gt;' ], rawurldecode( $m[1] ) );
                }
                $trail = "";
            } else { # Invalid form; output directly
                $s .= $prefix . '[[' . $line;
                continue;
            }
 
            $origLink = ltrim( $m[1], ' ' );
 
            # Don't allow internal links to pages containing
            # PROTO: where PROTO is a valid URL protocol; these
            # should be external links.
            if ( preg_match( '/^(?i:' . $this->mUrlProtocols . ')/', $origLink ) ) {
                $s .= $prefix . '[[' . $line;
                continue;
            }
 
            # Make subpage if necessary
            if ( $useSubpages ) {
                $link = Linker::normalizeSubpageLink(
                    $this->getTitle(), $origLink, $text
                );
            } else {
                $link = $origLink;
            }
 
            // \x7f isn't a default legal title char, so most likely strip
            // markers will force us into the "invalid form" path above.  But,
            // just in case, let's assert that xmlish tags aren't valid in
            // the title position.
            $unstrip = $this->mStripState->killMarkers( $link );
            $noMarkers = ( $unstrip === $link );
 
            $nt = $noMarkers ? Title::newFromText( $link ) : null;
            if ( $nt === null ) {
                $s .= $prefix . '[[' . $line;
                continue;
            }
 
            $ns = $nt->getNamespace();
            $iw = $nt->getInterwiki();
 
            $noforce = ( substr( $origLink, 0, 1 ) !== ':' );
 
            if ( $might_be_img ) { # if this is actually an invalid link
                if ( $ns === NS_FILE && $noforce ) { # but might be an image
                    $found = false;
                    while ( true ) {
                        # look at the next 'line' to see if we can close it there
                        $a->next();
                        $next_line = $a->current();
                        if ( $next_line === false || $next_line === null ) {
                            break;
                        }
                        $m = explode( ']]', $next_line, 3 );
                        if ( count( $m ) == 3 ) {
                            # the first ]] closes the inner link, the second the image
                            $found = true;
                            $text .= "[[{$m[0]}]]{$m[1]}";
                            $trail = $m[2];
                            break;
                        } elseif ( count( $m ) == 2 ) {
                            # if there's exactly one ]] that's fine, we'll keep looking
                            $text .= "[[{$m[0]}]]{$m[1]}";
                        } else {
                            # if $next_line is invalid too, we need look no further
                            $text .= '[[' . $next_line;
                            break;
                        }
                    }
                    if ( !$found ) {
                        # we couldn't find the end of this imageLink, so output it raw
                        # but don't ignore what might be perfectly normal links in the text we've examined
                        $holders->merge( $this->handleInternalLinks2( $text ) );
                        $s .= "{$prefix}[[$link|$text";
                        # note: no $trail, because without an end, there *is* no trail
                        continue;
                    }
                } else { # it's not an image, so output it raw
                    $s .= "{$prefix}[[$link|$text";
                    # note: no $trail, because without an end, there *is* no trail
                    continue;
                }
            }
 
            $wasblank = ( $text == '' );
            if ( $wasblank ) {
                $text = $link;
                if ( !$noforce ) {
                    # Strip off leading ':'
                    $text = substr( $text, 1 );
                }
            } else {
                # T6598 madness. Handle the quotes only if they come from the alternate part
                # [[Lista d''e paise d''o munno]] -> <a href="...">Lista d''e paise d''o munno</a>
                # [[Criticism of Harry Potter|Criticism of ''Harry Potter'']]
                #    -> <a href="Criticism of Harry Potter">Criticism of <i>Harry Potter</i></a>
                $text = $this->doQuotes( $text );
            }
 
            # Link not escaped by : , create the various objects
            if ( $noforce && !$nt->wasLocalInterwiki() ) {
                # Interwikis
                if (
                    $iw && $this->mOptions->getInterwikiMagic() && $nottalk && (
                        MediaWikiServices::getInstance()->getLanguageNameUtils()
                            ->getLanguageName(
                                $iw,
                                LanguageNameUtils::AUTONYMS,
                                LanguageNameUtils::DEFINED
                            )
                        || in_array( $iw, $this->svcOptions->get( 'ExtraInterlanguageLinkPrefixes' ) )
                    )
                ) {
                    # T26502: filter duplicates
                    if ( !isset( $this->mLangLinkLanguages[$iw] ) ) {
                        $this->mLangLinkLanguages[$iw] = true;
                        $this->mOutput->addLanguageLink( $nt->getFullText() );
                    }
 
                    $s = rtrim( $s . $prefix ) . $trail; # T175416
                    continue;
                }
 
                if ( $ns === NS_FILE ) {
                    if ( !$this->badFileLookup->isBadFile( $nt->getDBkey(), $this->getTitle() ) ) {
                        if ( $wasblank ) {
                            # if no parameters were passed, $text
                            # becomes something like "File:Foo.png",
                            # which we don't want to pass on to the
                            # image generator
                            $text = '';
                        } else {
                            # recursively parse links inside the image caption
                            # actually, this will parse them in any other parameters, too,
                            # but it might be hard to fix that, and it doesn't matter ATM
                            $text = $this->handleExternalLinks( $text );
                            $holders->merge( $this->handleInternalLinks2( $text ) );
                        }
                        # cloak any absolute URLs inside the image markup, so handleExternalLinks() won't touch them
                        $s .= $prefix . $this->armorLinks(
                            $this->makeImage( $nt, $text, $holders ) ) . $trail;
                        continue;
                    }
                } elseif ( $ns === NS_CATEGORY ) {
                    $s = rtrim( $s . $prefix ) . $trail; # T2087, T87753
 
                    if ( $wasblank ) {
                        $sortkey = $this->getDefaultSort();
                    } else {
                        $sortkey = $text;
                    }
                    $sortkey = Sanitizer::decodeCharReferences( $sortkey );
                    $sortkey = str_replace( "\n", '', $sortkey );
                    $sortkey = $this->getTargetLanguageConverter()->convertCategoryKey( $sortkey );
                    $this->mOutput->addCategory( $nt->getDBkey(), $sortkey );
 
                    continue;
                }
            }
 
            # Self-link checking. For some languages, variants of the title are checked in
            # LinkHolderArray::doVariants() to allow batching the existence checks necessary
            # for linking to a different variant.
            if ( $ns !== NS_SPECIAL && $nt->equals( $this->getTitle() ) && !$nt->hasFragment() ) {
                $s .= $prefix . Linker::makeSelfLinkObj( $nt, $text, '', $trail );
                continue;
            }
 
            # NS_MEDIA is a pseudo-namespace for linking directly to a file
            # @todo FIXME: Should do batch file existence checks, see comment below
            if ( $ns === NS_MEDIA ) {
                # Give extensions a chance to select the file revision for us
                $options = [];
                $descQuery = false;
                $this->hookRunner->onBeforeParserFetchFileAndTitle(
                    $this, $nt, $options, $descQuery );
                # Fetch and register the file (file title may be different via hooks)
                list( $file, $nt ) = $this->fetchFileAndTitle( $nt, $options );
                # Cloak with NOPARSE to avoid replacement in handleExternalLinks
                $s .= $prefix . $this->armorLinks(
                    Linker::makeMediaLinkFile( $nt, $file, $text ) ) . $trail;
                continue;
            }
 
            # Some titles, such as valid special pages or files in foreign repos, should
            # be shown as bluelinks even though they're not included in the page table
            # @todo FIXME: isAlwaysKnown() can be expensive for file links; we should really do
            # batch file existence checks for NS_FILE and NS_MEDIA
            if ( $iw == '' && $nt->isAlwaysKnown() ) {
                $this->mOutput->addLink( $nt );
                $s .= $this->makeKnownLinkHolder( $nt, $text, $trail, $prefix );
            } else {
                # Links will be added to the output link list after checking
                $s .= $holders->makeHolder( $nt, $text, $trail, $prefix );
            }
        }
        return $holders;
    }
 
    private function makeKnownLinkHolder( LinkTarget $nt, $text = '', $trail = '', $prefix = '' ) {
        list( $inside, $trail ) = Linker::splitTrail( $trail );
 
        if ( $text == '' ) {
            $text = htmlspecialchars( $this->titleFormatter->getPrefixedText( $nt ) );
        }
 
        $link = $this->getLinkRenderer()->makeKnownLink(
            $nt, new HtmlArmor( "$prefix$text$inside" )
        );
 
        return $this->armorLinks( $link ) . $trail;
    }
 
    private function armorLinks( $text ) {
        return preg_replace( '/\b((?i)' . $this->mUrlProtocols . ')/',
            self::MARKER_PREFIX . "NOPARSE$1", $text );
    }
 
    public function doBlockLevels( $text, $linestart ) {
        wfDeprecated( __METHOD__, '1.35' );
        return BlockLevelPass::doBlockLevels( $text, $linestart );
    }
 
    private function expandMagicVariable( $index, $frame = false ) {
        if (
            $this->hookRunner->onParserGetVariableValueVarCache( $this, $this->mVarCache ) &&
            isset( $this->mVarCache[$index] )
        ) {
            return $this->mVarCache[$index];
        }
 
        $ts = wfTimestamp( TS_UNIX, $this->mOptions->getTimestamp() );
        $this->hookRunner->onParserGetVariableValueTs( $this, $ts );
 
        $value = CoreMagicVariables::expand(
            $this, $index, $ts, $this->nsInfo, $this->svcOptions, $this->logger
        );
 
        if ( $value === null ) {
            // Not a defined core magic word
            $ret = null;
            $originalIndex = $index;
            $this->hookRunner->onParserGetVariableValueSwitch( $this,
                $this->mVarCache, $index, $ret, $frame );
                if ( $index !== $originalIndex ) {
                    wfDeprecatedMsg(
                        'A ParserGetVariableValueSwitch hook handler modified $index, ' .
                        'this is deprecated since MediaWiki 1.35',
                        '1.35', false, false
                    );
                }
                if ( !isset( $this->mVarCache[$originalIndex] ) ||
                    $this->mVarCache[$originalIndex] !== $ret ) {
                    wfDeprecatedMsg(
                        'A ParserGetVariableValueSwitch hook handler bypassed the cache, ' .
                        'this is deprecated since MediaWiki 1.35', '1.35', false, false
                    );
                }// FIXME: in the future, don't give this hook unrestricted
            // access to mVarCache; we can cache it ourselves by falling
            // through here.
            return $ret;
        }
 
        $this->mVarCache[$index] = $value;
 
        return $value;
    }
 
    private function initializeVariables() {
        $variableIDs = $this->magicWordFactory->getVariableIDs();
        $substIDs = $this->magicWordFactory->getSubstIDs();
 
        $this->mVariables = $this->magicWordFactory->newArray( $variableIDs );
        $this->mSubstWords = $this->magicWordFactory->newArray( $substIDs );
    }
 
    public function preprocessToDom( $text, $flags = 0 ) {
        return $this->getPreprocessor()->preprocessToObj( $text, $flags );
    }
 
    public function replaceVariables( $text, $frame = false, $argsOnly = false ) {
        # Is there any text? Also, Prevent too big inclusions!
        $textSize = strlen( $text );
        if ( $textSize < 1 || $textSize > $this->mOptions->getMaxIncludeSize() ) {
            return $text;
        }
 
        if ( $frame === false ) {
            $frame = $this->getPreprocessor()->newFrame();
        } elseif ( !( $frame instanceof PPFrame ) ) {
            $this->logger->debug(
                __METHOD__ . " called using plain parameters instead of " .
                "a PPFrame instance. Creating custom frame."
            );
            $frame = $this->getPreprocessor()->newCustomFrame( $frame );
        }
 
        $dom = $this->preprocessToDom( $text );
        $flags = $argsOnly ? PPFrame::NO_TEMPLATES : 0;
        $text = $frame->expand( $dom, $flags );
 
        return $text;
    }
 
    public function limitationWarn( $limitationType, $current = '', $max = '' ) {
        # does no harm if $current and $max are present but are unnecessary for the message
        # Not doing ->inLanguage( $this->mOptions->getUserLangObj() ), since this is shown
        # only during preview, and that would split the parser cache unnecessarily.
        $this->mOutput->addWarningMsg(
            "$limitationType-warning",
            Message::numParam( $current ),
            Message::numParam( $max )
        );
        $this->addTrackingCategory( "$limitationType-category" );
    }
 
    public function braceSubstitution( array $piece, PPFrame $frame ) {
        // Flags
 
        // $text has been filled
        $found = false;
        // wiki markup in $text should be escaped
        $nowiki = false;
        // $text is HTML, armour it against wikitext transformation
        $isHTML = false;
        // Force interwiki transclusion to be done in raw mode not rendered
        $forceRawInterwiki = false;
        // $text is a DOM node needing expansion in a child frame
        $isChildObj = false;
        // $text is a DOM node needing expansion in the current frame
        $isLocalObj = false;
 
        # Title object, where $text came from
        $title = false;
 
        # $part1 is the bit before the first |, and must contain only title characters.
        # Various prefixes will be stripped from it later.
        $titleWithSpaces = $frame->expand( $piece['title'] );
        $part1 = trim( $titleWithSpaces );
        $titleText = false;
 
        # Original title text preserved for various purposes
        $originalTitle = $part1;
 
        # $args is a list of argument nodes, starting from index 0, not including $part1
        # @todo FIXME: If piece['parts'] is null then the call to getLength()
        # below won't work b/c this $args isn't an object
        $args = ( $piece['parts'] == null ) ? [] : $piece['parts'];
 
        $profileSection = null; // profile templates
 
        $sawDeprecatedTemplateEquals = false; // T91154
 
        # SUBST
        // @phan-suppress-next-line PhanImpossibleCondition
        if ( !$found ) {
            $substMatch = $this->mSubstWords->matchStartAndRemove( $part1 );
 
            # Possibilities for substMatch: "subst", "safesubst" or FALSE
            # Decide whether to expand template or keep wikitext as-is.
            if ( $this->ot['wiki'] ) {
                if ( $substMatch === false ) {
                    $literal = true;  # literal when in PST with no prefix
                } else {
                    $literal = false; # expand when in PST with subst: or safesubst:
                }
            } else {
                if ( $substMatch == 'subst' ) {
                    $literal = true;  # literal when not in PST with plain subst:
                } else {
                    $literal = false; # expand when not in PST with safesubst: or no prefix
                }
            }
            if ( $literal ) {
                $text = $frame->virtualBracketedImplode( '{{', '|', '}}', $titleWithSpaces, $args );
                $isLocalObj = true;
                $found = true;
            }
        }
 
        # Variables
        if ( !$found && $args->getLength() == 0 ) {
            $id = $this->mVariables->matchStartToEnd( $part1 );
            if ( $id !== false ) {
                $text = $this->expandMagicVariable( $id, $frame );
                if ( $this->magicWordFactory->getCacheTTL( $id ) > -1 ) {
                    $this->mOutput->updateCacheExpiry(
                        $this->magicWordFactory->getCacheTTL( $id ) );
                }
                $found = true;
            }
        }
 
        # MSG, MSGNW and RAW
        if ( !$found ) {
            # Check for MSGNW:
            $mwMsgnw = $this->magicWordFactory->get( 'msgnw' );
            if ( $mwMsgnw->matchStartAndRemove( $part1 ) ) {
                $nowiki = true;
            } else {
                # Remove obsolete MSG:
                $mwMsg = $this->magicWordFactory->get( 'msg' );
                $mwMsg->matchStartAndRemove( $part1 );
            }
 
            # Check for RAW:
            $mwRaw = $this->magicWordFactory->get( 'raw' );
            if ( $mwRaw->matchStartAndRemove( $part1 ) ) {
                $forceRawInterwiki = true;
            }
        }
 
        # Parser functions
        if ( !$found ) {
            $colonPos = strpos( $part1, ':' );
            if ( $colonPos !== false ) {
                $func = substr( $part1, 0, $colonPos );
                $funcArgs = [ trim( substr( $part1, $colonPos + 1 ) ) ];
                $argsLength = $args->getLength();
                for ( $i = 0; $i < $argsLength; $i++ ) {
                    $funcArgs[] = $args->item( $i );
                }
 
                $result = $this->callParserFunction( $frame, $func, $funcArgs );
 
                // Extract any forwarded flags
                if ( isset( $result['title'] ) ) {
                    $title = $result['title'];
                }
                if ( isset( $result['found'] ) ) {
                    $found = $result['found'];
                }
                if ( array_key_exists( 'text', $result ) ) {
                    // a string or null
                    $text = $result['text'];
                }
                if ( isset( $result['nowiki'] ) ) {
                    $nowiki = $result['nowiki'];
                }
                if ( isset( $result['isHTML'] ) ) {
                    $isHTML = $result['isHTML'];
                }
                if ( isset( $result['forceRawInterwiki'] ) ) {
                    $forceRawInterwiki = $result['forceRawInterwiki'];
                }
                if ( isset( $result['isChildObj'] ) ) {
                    $isChildObj = $result['isChildObj'];
                }
                if ( isset( $result['isLocalObj'] ) ) {
                    $isLocalObj = $result['isLocalObj'];
                }
            }
        }
 
        # Finish mangling title and then check for loops.
        # Set $title to a Title object and $titleText to the PDBK
        if ( !$found ) {
            $ns = NS_TEMPLATE;
            # Split the title into page and subpage
            $subpage = '';
            $relative = Linker::normalizeSubpageLink(
                $this->getTitle(), $part1, $subpage
            );
            if ( $part1 !== $relative ) {
                $part1 = $relative;
                $ns = $this->getTitle()->getNamespace();
            }
            $title = Title::newFromText( $part1, $ns );
            if ( $title ) {
                $titleText = $title->getPrefixedText();
                # Check for language variants if the template is not found
                if ( $this->getTargetLanguageConverter()->hasVariants() && $title->getArticleID() == 0 ) {
                    $this->getTargetLanguageConverter()->findVariantLink( $part1, $title, true );
                }
                # Do recursion depth check
                $limit = $this->mOptions->getMaxTemplateDepth();
                if ( $frame->depth >= $limit ) {
                    $found = true;
                    $text = '<span class="error">'
                        . wfMessage( 'parser-template-recursion-depth-warning' )
                            ->numParams( $limit )->inContentLanguage()->text()
                        . '</span>';
                }
            }
        }
 
        # Load from database
        if ( !$found && $title ) {
            $profileSection = $this->mProfiler->scopedProfileIn( $title->getPrefixedDBkey() );
            if ( !$title->isExternal() ) {
                if ( $title->isSpecialPage()
                    && $this->mOptions->getAllowSpecialInclusion()
                    && $this->ot['html']
                ) {
                    $specialPage = $this->specialPageFactory->getPage( $title->getDBkey() );
                    // Pass the template arguments as URL parameters.
                    // "uselang" will have no effect since the Language object
                    // is forced to the one defined in ParserOptions.
                    $pageArgs = [];
                    $argsLength = $args->getLength();
                    for ( $i = 0; $i < $argsLength; $i++ ) {
                        $bits = $args->item( $i )->splitArg();
                        if ( strval( $bits['index'] ) === '' ) {
                            $name = trim( $frame->expand( $bits['name'], PPFrame::STRIP_COMMENTS ) );
                            $value = trim( $frame->expand( $bits['value'] ) );
                            $pageArgs[$name] = $value;
                        }
                    }
 
                    // Create a new context to execute the special page
                    $context = new RequestContext;
                    $context->setTitle( $title );
                    $context->setRequest( new FauxRequest( $pageArgs ) );
                    if ( $specialPage && $specialPage->maxIncludeCacheTime() === 0 ) {
                        $context->setUser( $this->userFactory->newFromUserIdentity( $this->getUserIdentity() ) );
                    } else {
                        // If this page is cached, then we better not be per user.
                        $context->setUser( User::newFromName( '127.0.0.1', false ) );
                    }
                    $context->setLanguage( $this->mOptions->getUserLangObj() );
                    $ret = $this->specialPageFactory->capturePath( $title, $context, $this->getLinkRenderer() );
                    if ( $ret ) {
                        $text = $context->getOutput()->getHTML();
                        $this->mOutput->addOutputPageMetadata( $context->getOutput() );
                        $found = true;
                        $isHTML = true;
                        if ( $specialPage && $specialPage->maxIncludeCacheTime() !== false ) {
                            $this->mOutput->updateRuntimeAdaptiveExpiry(
                                $specialPage->maxIncludeCacheTime()
                            );
                        }
                    }
                } elseif ( $this->nsInfo->isNonincludable( $title->getNamespace() ) ) {
                    $found = false; # access denied
                    $this->logger->debug(
                        __METHOD__ .
                        ": template inclusion denied for " . $title->getPrefixedDBkey()
                    );
                } else {
                    list( $text, $title ) = $this->getTemplateDom( $title );
                    if ( $text !== false ) {
                        $found = true;
                        $isChildObj = true;
                        if (
                            $title->getNamespace() === NS_TEMPLATE &&
                            $title->getDBkey() === '=' &&
                            $originalTitle === '='
                        ) {
                            // Note that we won't get here if `=` is evaluated
                            // (in the future) as a parser function, nor if
                            // the Template namespace is given explicitly,
                            // ie `{{Template:=}}`.  Only `{{=}}` triggers.
                            $sawDeprecatedTemplateEquals = true; // T91154
                        }
                    }
                }
 
                # If the title is valid but undisplayable, make a link to it
                if ( !$found && ( $this->ot['html'] || $this->ot['pre'] ) ) {
                    $text = "[[:$titleText]]";
                    $found = true;
                }
            } elseif ( $title->isTrans() ) {
                # Interwiki transclusion
                if ( $this->ot['html'] && !$forceRawInterwiki ) {
                    $text = $this->interwikiTransclude( $title, 'render' );
                    $isHTML = true;
                } else {
                    $text = $this->interwikiTransclude( $title, 'raw' );
                    # Preprocess it like a template
                    $text = $this->preprocessToDom( $text, Preprocessor::DOM_FOR_INCLUSION );
                    $isChildObj = true;
                }
                $found = true;
            }
 
            # Do infinite loop check
            # This has to be done after redirect resolution to avoid infinite loops via redirects
            if ( !$frame->loopCheck( $title ) ) {
                $found = true;
                $text = '<span class="error">'
                    . wfMessage( 'parser-template-loop-warning', $titleText )->inContentLanguage()->text()
                    . '</span>';
                $this->addTrackingCategory( 'template-loop-category' );
                $this->mOutput->addWarningMsg(
                    'template-loop-warning',
                    Message::plaintextParam( $titleText )
                );
                $this->logger->debug( __METHOD__ . ": template loop broken at '$titleText'" );
            }
        }
 
        # If we haven't found text to substitute by now, we're done
        # Recover the source wikitext and return it
        if ( !$found ) {
            $text = $frame->virtualBracketedImplode( '{{', '|', '}}', $titleWithSpaces, $args );
            if ( $profileSection ) {
                $this->mProfiler->scopedProfileOut( $profileSection );
            }
            return [ 'object' => $text ];
        }
 
        # Expand DOM-style return values in a child frame
        if ( $isChildObj ) {
            # Clean up argument array
            $newFrame = $frame->newChild( $args, $title );
 
            if ( $nowiki ) {
                $text = $newFrame->expand( $text, PPFrame::RECOVER_ORIG );
            } elseif ( $titleText !== false && $newFrame->isEmpty() ) {
                # Expansion is eligible for the empty-frame cache
                $text = $newFrame->cachedExpand( $titleText, $text );
            } else {
                # Uncached expansion
                $text = $newFrame->expand( $text );
            }
        }
        if ( $isLocalObj && $nowiki ) {
            $text = $frame->expand( $text, PPFrame::RECOVER_ORIG );
            $isLocalObj = false;
        }
 
        if ( $profileSection ) {
            $this->mProfiler->scopedProfileOut( $profileSection );
        }
        if (
            $sawDeprecatedTemplateEquals &&
            $this->mStripState->unstripBoth( $text ) !== '='
        ) {
            // T91154: {{=}} is deprecated when it doesn't expand to `=`;
            // use {{Template:=}} if you must.
            $this->addTrackingCategory( 'template-equals-category' );
            $this->mOutput->addWarningMsg( 'template-equals-warning' );
        }
 
        # Replace raw HTML by a placeholder
        if ( $isHTML ) {
            // @phan-suppress-next-line SecurityCheck-XSS Mixed mode, here html and safe
            $text = $this->insertStripItem( $text );
        } elseif ( $nowiki && ( $this->ot['html'] || $this->ot['pre'] ) ) {
            # Escape nowiki-style return values
            // @phan-suppress-next-line SecurityCheck-DoubleEscaped Mixed mode, here html and safe
            $text = wfEscapeWikiText( $text );
        } elseif ( is_string( $text )
            && !$piece['lineStart']
            && preg_match( '/^(?:{\\||:|;|#|\*)/', $text )
        ) {
            # T2529: if the template begins with a table or block-level
            # element, it should be treated as beginning a new line.
            # This behavior is somewhat controversial.
            $text = "\n" . $text;
        }
 
        if ( is_string( $text ) && !$this->incrementIncludeSize( 'post-expand', strlen( $text ) ) ) {
            # Error, oversize inclusion
            if ( $titleText !== false ) {
                # Make a working, properly escaped link if possible (T25588)
                $text = "[[:$titleText]]";
            } else {
                # This will probably not be a working link, but at least it may
                # provide some hint of where the problem is
                $originalTitle = preg_replace( '/^:/', '', $originalTitle );
                $text = "[[:$originalTitle]]";
            }
            $text .= $this->insertStripItem( '<!-- WARNING: template omitted, '
                . 'post-expand include size too large -->' );
            $this->limitationWarn( 'post-expand-template-inclusion' );
        }
 
        if ( $isLocalObj ) {
            $ret = [ 'object' => $text ];
        } else {
            $ret = [ 'text' => $text ];
        }
 
        return $ret;
    }
 
    public function callParserFunction( PPFrame $frame, $function, array $args = [] ) {
        # Case sensitive functions
        if ( isset( $this->mFunctionSynonyms[1][$function] ) ) {
            $function = $this->mFunctionSynonyms[1][$function];
        } else {
            # Case insensitive functions
            $function = $this->contLang->lc( $function );
            if ( isset( $this->mFunctionSynonyms[0][$function] ) ) {
                $function = $this->mFunctionSynonyms[0][$function];
            } else {
                return [ 'found' => false ];
            }
        }
 
        list( $callback, $flags ) = $this->mFunctionHooks[$function];
 
        $allArgs = [ $this ];
        if ( $flags & self::SFH_OBJECT_ARGS ) {
            # Convert arguments to PPNodes and collect for appending to $allArgs
            $funcArgs = [];
            foreach ( $args as $k => $v ) {
                if ( $v instanceof PPNode || $k === 0 ) {
                    $funcArgs[] = $v;
                } else {
                    $funcArgs[] = $this->mPreprocessor->newPartNodeArray( [ $k => $v ] )->item( 0 );
                }
            }
 
            # Add a frame parameter, and pass the arguments as an array
            $allArgs[] = $frame;
            $allArgs[] = $funcArgs;
        } else {
            # Convert arguments to plain text and append to $allArgs
            foreach ( $args as $k => $v ) {
                if ( $v instanceof PPNode ) {
                    $allArgs[] = trim( $frame->expand( $v ) );
                } elseif ( is_int( $k ) && $k >= 0 ) {
                    $allArgs[] = trim( $v );
                } else {
                    $allArgs[] = trim( "$k=$v" );
                }
            }
        }
 
        $result = $callback( ...$allArgs );
 
        # The interface for function hooks allows them to return a wikitext
        # string or an array containing the string and any flags. This mungs
        # things around to match what this method should return.
        if ( !is_array( $result ) ) {
            $result = [
                'found' => true,
                'text' => $result,
            ];
        } else {
            if ( isset( $result[0] ) && !isset( $result['text'] ) ) {
                $result['text'] = $result[0];
            }
            unset( $result[0] );
            $result += [
                'found' => true,
            ];
        }
 
        $noparse = true;
        $preprocessFlags = 0;
        if ( isset( $result['noparse'] ) ) {
            $noparse = $result['noparse'];
        }
        if ( isset( $result['preprocessFlags'] ) ) {
            $preprocessFlags = $result['preprocessFlags'];
        }
 
        if ( !$noparse ) {
            $result['text'] = $this->preprocessToDom( $result['text'], $preprocessFlags );
            $result['isChildObj'] = true;
        }
 
        return $result;
    }
 
    public function getTemplateDom( LinkTarget $title ) {
        $cacheTitle = $title;
        $titleKey = CacheKeyHelper::getKeyForPage( $title );
 
        if ( isset( $this->mTplRedirCache[$titleKey] ) ) {
            list( $ns, $dbk ) = $this->mTplRedirCache[$titleKey];
            $title = Title::makeTitle( $ns, $dbk );
            $titleKey = CacheKeyHelper::getKeyForPage( $title );
        }
        if ( isset( $this->mTplDomCache[$titleKey] ) ) {
            return [ $this->mTplDomCache[$titleKey], $title ];
        }
 
        # Cache miss, go to the database
        list( $text, $title ) = $this->fetchTemplateAndTitle( $title );
 
        if ( $text === false ) {
            $this->mTplDomCache[$titleKey] = false;
            return [ false, $title ];
        }
 
        $dom = $this->preprocessToDom( $text, Preprocessor::DOM_FOR_INCLUSION );
        $this->mTplDomCache[$titleKey] = $dom;
 
        if ( !$title->isSamePageAs( $cacheTitle ) ) {
            $this->mTplRedirCache[ CacheKeyHelper::getKeyForPage( $cacheTitle ) ] =
                [ $title->getNamespace(), $title->getDBkey() ];
        }
 
        return [ $dom, $title ];
    }
 
    public function fetchCurrentRevisionRecordOfTitle( LinkTarget $link ) {
        $cacheKey = CacheKeyHelper::getKeyForPage( $link );
        if ( !$this->currentRevisionCache ) {
            $this->currentRevisionCache = new MapCacheLRU( 100 );
        }
        if ( !$this->currentRevisionCache->has( $cacheKey ) ) {
            $title = Title::castFromLinkTarget( $link ); // hook signature compat
            $revisionRecord =
                // Defaults to Parser::statelessFetchRevisionRecord()
                call_user_func(
                    $this->mOptions->getCurrentRevisionRecordCallback(),
                    $title,
                    $this
                );
            if ( !$revisionRecord ) {
                // Parser::statelessFetchRevisionRecord() can return false;
                // normalize it to null.
                $revisionRecord = null;
            }
            $this->currentRevisionCache->set( $cacheKey, $revisionRecord );
        }
        return $this->currentRevisionCache->get( $cacheKey );
    }
 
    public function isCurrentRevisionOfTitleCached( LinkTarget $link ) {
        $key = CacheKeyHelper::getKeyForPage( $link );
        return (
            $this->currentRevisionCache &&
            $this->currentRevisionCache->has( $key )
        );
    }
 
    public static function statelessFetchRevisionRecord( LinkTarget $link, $parser = null ) {
        if ( $link instanceof PageIdentity ) {
            // probably a Title, just use it.
            $page = $link;
        } else {
            // XXX: use RevisionStore::getPageForLink()!
            //      ...but get the info for the current revision at the same time?
            //      Should RevisionStore::getKnownCurrentRevision accept a LinkTarget?
            $page = Title::castFromLinkTarget( $link );
        }
 
        $revRecord = MediaWikiServices::getInstance()
            ->getRevisionLookup()
            ->getKnownCurrentRevision( $page );
        return $revRecord;
    }
 
    public function fetchTemplateAndTitle( LinkTarget $link ) {
        // Use Title for compatibility with callbacks and return type
        $title = Title::castFromLinkTarget( $link );
 
        // Defaults to Parser::statelessFetchTemplate()
        $templateCb = $this->mOptions->getTemplateCallback();
        $stuff = call_user_func( $templateCb, $title, $this );
        if ( isset( $stuff['revision-record'] ) ) {
            $revRecord = $stuff['revision-record'];
        } else {
            $revRecord = null;
        }
 
        $text = $stuff['text'];
        if ( is_string( $stuff['text'] ) ) {
            // We use U+007F DELETE to distinguish strip markers from regular text
            $text = strtr( $text, "\x7f", "?" );
        }
        $finalTitle = $stuff['finalTitle'] ?? $title;
        foreach ( ( $stuff['deps'] ?? [] ) as $dep ) {
            $this->mOutput->addTemplate( $dep['title'], $dep['page_id'], $dep['rev_id'] );
            if ( $dep['title']->equals( $this->getTitle() ) && $revRecord instanceof RevisionRecord ) {
                // Self-transclusion; final result may change based on the new page version
                try {
                    $sha1 = $revRecord->getSha1();
                } catch ( RevisionAccessException $e ) {
                    $sha1 = null;
                }
                $this->setOutputFlag( ParserOutputFlags::VARY_REVISION_SHA1, 'Self transclusion' );
                $this->getOutput()->setRevisionUsedSha1Base36( $sha1 );
            }
        }
 
        return [ $text, $finalTitle ];
    }
 
    public static function statelessFetchTemplate( $page, $parser = false ) {
        $title = Title::castFromLinkTarget( $page ); // for compatibility with return type
        $text = $skip = false;
        $finalTitle = $title;
        $deps = [];
        $revRecord = null;
        $contextTitle = $parser ? $parser->getTitle() : null;
 
        # Loop to fetch the article, with up to 2 redirects
        $revLookup = MediaWikiServices::getInstance()->getRevisionLookup();
        for ( $i = 0; $i < 3 && is_object( $title ); $i++ ) {
            # Give extensions a chance to select the revision instead
            $revRecord = null; # Assume no hook
            $id = false; # Assume current
            $origTitle = $title;
            $titleChanged = false;
            Hooks::runner()->onBeforeParserFetchTemplateRevisionRecord(
                # The $title is a not a PageIdentity, as it may
                # contain fragments or even represent an attempt to transclude
                # a broken or otherwise-missing Title, which the hook may
                # fix up.  Similarly, the $contextTitle may represent a special
                # page or other page which "exists" as a parsing context but
                # is not in the DB.
                $contextTitle, $title,
                $skip, $revRecord
            );
            if ( !$skip && !$revRecord ) {
                # Deprecated legacy hook
                Hooks::runner()->onBeforeParserFetchTemplateAndtitle(
                    $parser, $title, $skip, $id
                );
            }
 
            if ( $skip ) {
                $text = false;
                $deps[] = [
                    'title' => $title,
                    'page_id' => $title->getArticleID(),
                    'rev_id' => null
                ];
                break;
            }
            # Get the revision
            if ( !$revRecord ) {
                if ( $id ) {
                    # Handle $id returned by deprecated legacy hook
                    $revRecord = $revLookup->getRevisionById( $id );
                } elseif ( $parser ) {
                    $revRecord = $parser->fetchCurrentRevisionRecordOfTitle( $title );
                } else {
                    $revRecord = $revLookup->getRevisionByTitle( $title );
                }
            }
            if ( $revRecord ) {
                # Update title, as $revRecord may have been changed by hook
                $title = Title::newFromLinkTarget(
                    $revRecord->getPageAsLinkTarget()
                );
                $deps[] = [
                    'title' => $title,
                    'page_id' => $revRecord->getPageId(),
                    'rev_id' => $revRecord->getId(),
                ];
            } else {
                $deps[] = [
                    'title' => $title,
                    'page_id' => $title->getArticleID(),
                    'rev_id' => null,
                ];
            }
            if ( !$title->equals( $origTitle ) ) {
                # If we fetched a rev from a different title, register
                # the original title too...
                $deps[] = [
                    'title' => $origTitle,
                    'page_id' => $origTitle->getArticleID(),
                    'rev_id' => null,
                ];
                $titleChanged = true;
            }
            # If there is no current revision, there is no page
            if ( $revRecord === null || $revRecord->getId() === null ) {
                $linkCache = MediaWikiServices::getInstance()->getLinkCache();
                $linkCache->addBadLinkObj( $title );
            }
            if ( $revRecord ) {
                if ( $titleChanged && !$revRecord->hasSlot( SlotRecord::MAIN ) ) {
                    // We've added this (missing) title to the dependencies;
                    // give the hook another chance to redirect it to an
                    // actual page.
                    $text = false;
                    $finalTitle = $title;
                    continue;
                }
                if ( $revRecord->hasSlot( SlotRecord::MAIN ) ) { // T276476
                    $content = $revRecord->getContent( SlotRecord::MAIN );
                    $text = $content ? $content->getWikitextForTransclusion() : null;
                } else {
                    $text = false;
                }
 
                if ( $text === false || $text === null ) {
                    $text = false;
                    break;
                }
            } elseif ( $title->getNamespace() === NS_MEDIAWIKI ) {
                $message = wfMessage( MediaWikiServices::getInstance()->getContentLanguage()->
                    lcfirst( $title->getText() ) )->inContentLanguage();
                if ( !$message->exists() ) {
                    $text = false;
                    break;
                }
                $text = $message->plain();
                break;
            } else {
                break;
            }
            if ( !$content ) {
                break;
            }
            # Redirect?
            $finalTitle = $title;
            $title = $content->getRedirectTarget();
        }
 
        $retValues = [
            // previously, when this also returned a Revision object, we set
            // 'revision-record' to false instead of null if it was unavailable,
            // so that callers to use isset and then rely on the revision-record
            // key instead of the revision key, even if there was no corresponding
            // object - we continue to set to false here for backwards compatability
            'revision-record' => $revRecord ?: false,
            'text' => $text,
            'finalTitle' => $finalTitle,
            'deps' => $deps
        ];
        return $retValues;
    }
 
    public function fetchFileAndTitle( LinkTarget $link, array $options = [] ) {
        $file = $this->fetchFileNoRegister( $link, $options );
 
        $time = $file ? $file->getTimestamp() : false;
        $sha1 = $file ? $file->getSha1() : false;
        # Register the file as a dependency...
        $this->mOutput->addImage( $link->getDBkey(), $time, $sha1 );
        if ( $file && !$link->isSameLinkAs( $file->getTitle() ) ) {
            # Update fetched file title
            $page = $file->getTitle();
            $this->mOutput->addImage( $page->getDBkey(), $time, $sha1 );
        }
 
        $title = Title::castFromLinkTarget( $link ); // for return type compat
        return [ $file, $title ];
    }
 
    protected function fetchFileNoRegister( LinkTarget $link, array $options = [] ) {
        if ( isset( $options['broken'] ) ) {
            $file = false; // broken thumbnail forced by hook
        } else {
            $repoGroup = MediaWikiServices::getInstance()->getRepoGroup();
            if ( isset( $options['sha1'] ) ) { // get by (sha1,timestamp)
                $file = $repoGroup->findFileFromKey( $options['sha1'], $options );
            } else { // get by (name,timestamp)
                $file = $repoGroup->findFile( $link, $options );
            }
        }
        return $file;
    }
 
    public function interwikiTransclude( LinkTarget $link, $action ) {
        if ( !$this->svcOptions->get( 'EnableScaryTranscluding' ) ) {
            return wfMessage( 'scarytranscludedisabled' )->inContentLanguage()->text();
        }
 
        // TODO: extract relevant functionality from Title
        $title = Title::castFromLinkTarget( $link );
 
        $url = $title->getFullURL( [ 'action' => $action ] );
        if ( strlen( $url ) > 1024 ) {
            return wfMessage( 'scarytranscludetoolong' )->inContentLanguage()->text();
        }
 
        $wikiId = $title->getTransWikiID(); // remote wiki ID or false
 
        $fname = __METHOD__;
        $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
 
        $data = $cache->getWithSetCallback(
            $cache->makeGlobalKey(
                'interwiki-transclude',
                ( $wikiId !== false ) ? $wikiId : 'external',
                sha1( $url )
            ),
            $this->svcOptions->get( 'TranscludeCacheExpiry' ),
            function ( $oldValue, &$ttl ) use ( $url, $fname, $cache ) {
                $req = $this->httpRequestFactory->create( $url, [], $fname );
 
                $status = $req->execute(); // Status object
                if ( !$status->isOK() ) {
                    $ttl = $cache::TTL_UNCACHEABLE;
                } elseif ( $req->getResponseHeader( 'X-Database-Lagged' ) !== null ) {
                    $ttl = min( $cache::TTL_LAGGED, $ttl );
                }
 
                return [
                    'text' => $status->isOK() ? $req->getContent() : null,
                    'code' => $req->getStatus()
                ];
            },
            [
                'checkKeys' => ( $wikiId !== false )
                    ? [ $cache->makeGlobalKey( 'interwiki-page', $wikiId, $title->getDBkey() ) ]
                    : [],
                'pcGroup' => 'interwiki-transclude:5',
                'pcTTL' => $cache::TTL_PROC_LONG
            ]
        );
 
        if ( is_string( $data['text'] ) ) {
            $text = $data['text'];
        } elseif ( $data['code'] != 200 ) {
            // Though we failed to fetch the content, this status is useless.
            $text = wfMessage( 'scarytranscludefailed-httpstatus' )
                ->params( $url, $data['code'] )->inContentLanguage()->text();
        } else {
            $text = wfMessage( 'scarytranscludefailed', $url )->inContentLanguage()->text();
        }
 
        return $text;
    }
 
    public function argSubstitution( array $piece, PPFrame $frame ) {
        $error = false;
        $parts = $piece['parts'];
        $nameWithSpaces = $frame->expand( $piece['title'] );
        $argName = trim( $nameWithSpaces );
        $object = false;
        $text = $frame->getArgument( $argName );
        if ( $text === false && $parts->getLength() > 0
            && ( $this->ot['html']
                || $this->ot['pre']
                || ( $this->ot['wiki'] && $frame->isTemplate() )
            )
        ) {
            # No match in frame, use the supplied default
            $object = $parts->item( 0 )->getChildren();
        }
        if ( !$this->incrementIncludeSize( 'arg', strlen( $text ) ) ) {
            $error = '<!-- WARNING: argument omitted, expansion size too large -->';
            $this->limitationWarn( 'post-expand-template-argument' );
        }
 
        if ( $text === false && $object === false ) {
            # No match anywhere
            $object = $frame->virtualBracketedImplode( '{{{', '|', '}}}', $nameWithSpaces, $parts );
        }
        if ( $error !== false ) {
            $text .= $error;
        }
        if ( $object !== false ) {
            $ret = [ 'object' => $object ];
        } else {
            $ret = [ 'text' => $text ];
        }
 
        return $ret;
    }
 
    public function extensionSubstitution( array $params, PPFrame $frame ) {
        static $errorStr = '<span class="error">';
        static $errorLen = 20;
 
        $name = $frame->expand( $params['name'] );
        if ( substr( $name, 0, $errorLen ) === $errorStr ) {
            // Probably expansion depth or node count exceeded. Just punt the
            // error up.
            return $name;
        }
 
        $attrText = !isset( $params['attr'] ) ? null : $frame->expand( $params['attr'] );
        if ( substr( $attrText, 0, $errorLen ) === $errorStr ) {
            // See above
            return $attrText;
        }
 
        // We can't safely check if the expansion for $content resulted in an
        // error, because the content could happen to be the error string
        // (T149622).
        $content = !isset( $params['inner'] ) ? null : $frame->expand( $params['inner'] );
 
        $marker = self::MARKER_PREFIX . "-$name-"
            . sprintf( '%08X', $this->mMarkerIndex++ ) . self::MARKER_SUFFIX;
 
        $markerType = 'general';
        if ( $this->ot['html'] ) {
            $name = strtolower( $name );
            $attributes = Sanitizer::decodeTagAttributes( $attrText );
            if ( isset( $params['attributes'] ) ) {
                $attributes += $params['attributes'];
            }
 
            if ( isset( $this->mTagHooks[$name] ) ) {
                // Note that $content may be null here, for example if the
                // tag is self-closed.
                $output = call_user_func_array( $this->mTagHooks[$name],
                    [ $content, $attributes, $this, $frame ] );
            } else {
                $output = '<span class="error">Invalid tag extension name: ' .
                    htmlspecialchars( $name ) . '</span>';
            }
 
            if ( is_array( $output ) ) {
                // Extract flags
                $flags = $output;
                $output = $flags[0];
                if ( isset( $flags['markerType'] ) ) {
                    $markerType = $flags['markerType'];
                }
            }
        } else {
            if ( $attrText === null ) {
                $attrText = '';
            }
            if ( isset( $params['attributes'] ) ) {
                foreach ( $params['attributes'] as $attrName => $attrValue ) {
                    $attrText .= ' ' . htmlspecialchars( $attrName ) . '="' .
                        htmlspecialchars( $attrValue ) . '"';
                }
            }
            if ( $content === null ) {
                $output = "<$name$attrText/>";
            } else {
                $close = $params['close'] === null ? '' : $frame->expand( $params['close'] );
                if ( substr( $close, 0, $errorLen ) === $errorStr ) {
                    // See above
                    return $close;
                }
                $output = "<$name$attrText>$content$close";
            }
        }
 
        if ( $markerType === 'none' ) {
            return $output;
        } elseif ( $markerType === 'nowiki' ) {
            $this->mStripState->addNoWiki( $marker, $output );
        } elseif ( $markerType === 'general' ) {
            $this->mStripState->addGeneral( $marker, $output );
        } else {
            throw new MWException( __METHOD__ . ': invalid marker type' );
        }
        return $marker;
    }
 
    private function incrementIncludeSize( $type, $size ) {
        if ( $this->mIncludeSizes[$type] + $size > $this->mOptions->getMaxIncludeSize() ) {
            return false;
        } else {
            $this->mIncludeSizes[$type] += $size;
            return true;
        }
    }
 
    public function incrementExpensiveFunctionCount() {
        $this->mExpensiveFunctionCount++;
        return $this->mExpensiveFunctionCount <= $this->mOptions->getExpensiveParserFunctionLimit();
    }
 
    private function handleDoubleUnderscore( $text ) {
        # The position of __TOC__ needs to be recorded
        $mw = $this->magicWordFactory->get( 'toc' );
        if ( $mw->match( $text ) ) {
            $this->mShowToc = true;
            $this->mForceTocPosition = true;
 
            # Set a placeholder. At the end we'll fill it in with the TOC.
            $text = $mw->replace( self::TOC_PLACEHOLDER, $text, 1 );
 
            # Only keep the first one.
            $text = $mw->replace( '', $text );
        }
 
        # Now match and remove the rest of them
        $mwa = $this->magicWordFactory->getDoubleUnderscoreArray();
        $this->mDoubleUnderscores = $mwa->matchAndRemove( $text );
 
        if ( isset( $this->mDoubleUnderscores['nogallery'] ) ) {
            $this->mOutput->setNoGallery( true );
        }
        if ( isset( $this->mDoubleUnderscores['notoc'] ) && !$this->mForceTocPosition ) {
            $this->mShowToc = false;
        }
        if ( isset( $this->mDoubleUnderscores['hiddencat'] )
            && $this->getTitle()->getNamespace() === NS_CATEGORY
        ) {
            $this->addTrackingCategory( 'hidden-category-category' );
        }
        # (T10068) Allow control over whether robots index a page.
        # __INDEX__ always overrides __NOINDEX__, see T16899
        if ( isset( $this->mDoubleUnderscores['noindex'] ) && $this->getTitle()->canUseNoindex() ) {
            $this->mOutput->setIndexPolicy( 'noindex' );
            $this->addTrackingCategory( 'noindex-category' );
        }
        if ( isset( $this->mDoubleUnderscores['index'] ) && $this->getTitle()->canUseNoindex() ) {
            $this->mOutput->setIndexPolicy( 'index' );
            $this->addTrackingCategory( 'index-category' );
        }
 
        # Cache all double underscores in the database
        foreach ( $this->mDoubleUnderscores as $key => $val ) {
            $this->mOutput->setPageProperty( $key, '' );
        }
 
        return $text;
    }
 
    public function addTrackingCategory( $msg ) {
        return $this->trackingCategories->addTrackingCategory(
            $this->mOutput, $msg, $this->getPage()
        );
    }
 
    private function finalizeHeadings( $text, $origText, $isMain = true ) {
        # Inhibit editsection links if requested in the page
        if ( isset( $this->mDoubleUnderscores['noeditsection'] ) ) {
            $maybeShowEditLink = false;
        } else {
            $maybeShowEditLink = true; /* Actual presence will depend on post-cache transforms */
        }
 
        # Get all headlines for numbering them and adding funky stuff like [edit]
        # links - this is for later, but we need the number of headlines right now
        # NOTE: white space in headings have been trimmed in handleHeadings. They shouldn't
        # be trimmed here since whitespace in HTML headings is significant.
        $matches = [];
        $numMatches = preg_match_all(
            '/<H(?P<level>[1-6])(?P<attrib>.*?>)(?P<header>[\s\S]*?)<\/H[1-6] *>/i',
            $text,
            $matches
        );
 
        # if there are fewer than 4 headlines in the article, do not show TOC
        # unless it's been explicitly enabled.
        $enoughToc = $this->mShowToc &&
            ( ( $numMatches >= 4 ) || $this->mForceTocPosition );
 
        # Allow user to stipulate that a page should have a "new section"
        # link added via __NEWSECTIONLINK__
        if ( isset( $this->mDoubleUnderscores['newsectionlink'] ) ) {
            $this->mOutput->setNewSection( true );
        }
 
        # Allow user to remove the "new section"
        # link via __NONEWSECTIONLINK__
        if ( isset( $this->mDoubleUnderscores['nonewsectionlink'] ) ) {
            $this->mOutput->setHideNewSection( true );
        }
 
        # if the string __FORCETOC__ (not case-sensitive) occurs in the HTML,
        # override above conditions and always show TOC above first header
        if ( isset( $this->mDoubleUnderscores['forcetoc'] ) ) {
            $this->mShowToc = true;
            $enoughToc = true;
        }
 
        # headline counter
        $headlineCount = 0;
        $numVisible = 0;
 
        # Ugh .. the TOC should have neat indentation levels which can be
        # passed to the skin functions. These are determined here
        $toc = '';
        $full = '';
        $head = [];
        $sublevelCount = [];
        $levelCount = [];
        $level = 0;
        $prevlevel = 0;
        $toclevel = 0;
        $prevtoclevel = 0;
        $markerRegex = self::MARKER_PREFIX . "-h-(\d+)-" . self::MARKER_SUFFIX;
        $baseTitleText = $this->getTitle()->getPrefixedDBkey();
        $oldType = $this->mOutputType;
        $this->setOutputType( self::OT_WIKI );
        $frame = $this->getPreprocessor()->newFrame();
        $root = $this->preprocessToDom( $origText );
        $node = $root->getFirstChild();
        $byteOffset = 0;
        $tocraw = [];
        $refers = [];
 
        $headlines = $numMatches !== false ? $matches[3] : [];
 
        $maxTocLevel = $this->svcOptions->get( 'MaxTocLevel' );
        foreach ( $headlines as $headline ) {
            $isTemplate = false;
            $titleText = false;
            $sectionIndex = false;
            $numbering = '';
            $markerMatches = [];
            if ( preg_match( "/^$markerRegex/", $headline, $markerMatches ) ) {
                $serial = $markerMatches[1];
                list( $titleText, $sectionIndex ) = $this->mHeadings[$serial];
                $isTemplate = ( $titleText != $baseTitleText );
                $headline = preg_replace( "/^$markerRegex\\s*/", "", $headline );
            }
 
            if ( $toclevel ) {
                $prevlevel = $level;
            }
            $level = $matches[1][$headlineCount];
 
            if ( $level > $prevlevel ) {
                # Increase TOC level
                $toclevel++;
                $sublevelCount[$toclevel] = 0;
                if ( $toclevel < $maxTocLevel ) {
                    $prevtoclevel = $toclevel;
                    $toc .= Linker::tocIndent();
                    $numVisible++;
                }
            } elseif ( $level < $prevlevel && $toclevel > 1 ) {
                # Decrease TOC level, find level to jump to
 
                for ( $i = $toclevel; $i > 0; $i-- ) {
                    // @phan-suppress-next-line PhanTypeInvalidDimOffset
                    if ( $levelCount[$i] == $level ) {
                        # Found last matching level
                        $toclevel = $i;
                        break;
                    } elseif ( $levelCount[$i] < $level ) {
                        // @phan-suppress-previous-line PhanTypeInvalidDimOffset
                        # Found first matching level below current level
                        $toclevel = $i + 1;
                        break;
                    }
                }
                if ( $i == 0 ) {
                    $toclevel = 1;
                }
                if ( $toclevel < $maxTocLevel ) {
                    if ( $prevtoclevel < $maxTocLevel ) {
                        # Unindent only if the previous toc level was shown :p
                        $toc .= Linker::tocUnindent( $prevtoclevel - $toclevel );
                        $prevtoclevel = $toclevel;
                    } else {
                        $toc .= Linker::tocLineEnd();
                    }
                }
            } else {
                # No change in level, end TOC line
                if ( $toclevel < $maxTocLevel ) {
                    $toc .= Linker::tocLineEnd();
                }
            }
 
            $levelCount[$toclevel] = $level;
 
            # count number of headlines for each level
            $sublevelCount[$toclevel]++;
            $dot = 0;
            for ( $i = 1; $i <= $toclevel; $i++ ) {
                if ( !empty( $sublevelCount[$i] ) ) {
                    if ( $dot ) {
                        $numbering .= '.';
                    }
                    $numbering .= $this->getTargetLanguage()->formatNum( $sublevelCount[$i] );
                    $dot = 1;
                }
            }
 
            # The safe header is a version of the header text safe to use for links
 
            # Remove link placeholders by the link text.
            #     <!--LINK number-->
            # turns into
            #     link text with suffix
            # Do this before unstrip since link text can contain strip markers
            $safeHeadline = $this->replaceLinkHoldersText( $headline );
 
            # Avoid insertion of weird stuff like <math> by expanding the relevant sections
            $safeHeadline = $this->mStripState->unstripBoth( $safeHeadline );
 
            # Remove any <style> or <script> tags (T198618)
            $safeHeadline = preg_replace(
                '#<(style|script)(?: [^>]*[^>/])?>.*?</\1>#is',
                '',
                $safeHeadline
            );
 
            # Strip out HTML (first regex removes any tag not allowed)
            # Allowed tags are:
            # * <sup> and <sub> (T10393)
            # * <i> (T28375)
            # * <b> (r105284)
            # * <bdi> (T74884)
            # * <span dir="rtl"> and <span dir="ltr"> (T37167)
            # * <s> and <strike> (T35715)
            # We strip any parameter from accepted tags (second regex), except dir="rtl|ltr" from <span>,
            # to allow setting directionality in toc items.
            $tocline = preg_replace(
                [
                    '#<(?!/?(span|sup|sub|bdi|i|b|s|strike)(?: [^>]*)?>).*?>#',
                    '#<(/?(?:span(?: dir="(?:rtl|ltr)")?|sup|sub|bdi|i|b|s|strike))(?: .*?)?>#'
                ],
                [ '', '<$1>' ],
                $safeHeadline
            );
 
            # Strip '<span></span>', which is the result from the above if
            # <span id="foo"></span> is used to produce an additional anchor
            # for a section.
            $tocline = str_replace( '<span></span>', '', $tocline );
 
            $tocline = trim( $tocline );
 
            # For the anchor, strip out HTML-y stuff period
            $safeHeadline = preg_replace( '/<.*?>/', '', $safeHeadline );
            $safeHeadline = Sanitizer::normalizeSectionNameWhitespace( $safeHeadline );
 
            # Save headline for section edit hint before it's escaped
            $headlineHint = $safeHeadline;
 
            # Decode HTML entities
            $safeHeadline = Sanitizer::decodeCharReferences( $safeHeadline );
 
            $safeHeadline = self::normalizeSectionName( $safeHeadline );
 
            $fallbackHeadline = Sanitizer::escapeIdForAttribute( $safeHeadline, Sanitizer::ID_FALLBACK );
            $linkAnchor = Sanitizer::escapeIdForLink( $safeHeadline );
            $safeHeadline = Sanitizer::escapeIdForAttribute( $safeHeadline, Sanitizer::ID_PRIMARY );
            if ( $fallbackHeadline === $safeHeadline ) {
                # No reason to have both (in fact, we can't)
                $fallbackHeadline = false;
            }
 
            # HTML IDs must be case-insensitively unique for IE compatibility (T12721).
            $arrayKey = strtolower( $safeHeadline );
            if ( $fallbackHeadline === false ) {
                $fallbackArrayKey = false;
            } else {
                $fallbackArrayKey = strtolower( $fallbackHeadline );
            }
 
            # Create the anchor for linking from the TOC to the section
            $anchor = $safeHeadline;
            $fallbackAnchor = $fallbackHeadline;
            if ( isset( $refers[$arrayKey] ) ) {
                for ( $i = 2; isset( $refers["${arrayKey}_$i"] ); ++$i );
                $anchor .= "_$i";
                $linkAnchor .= "_$i";
                $refers["${arrayKey}_$i"] = true;
            } else {
                $refers[$arrayKey] = true;
            }
            if ( $fallbackHeadline !== false && isset( $refers[$fallbackArrayKey] ) ) {
                for ( $i = 2; isset( $refers["${fallbackArrayKey}_$i"] ); ++$i );
                $fallbackAnchor .= "_$i";
                $refers["${fallbackArrayKey}_$i"] = true;
            } else {
                $refers[$fallbackArrayKey] = true;
            }
 
            if ( $enoughToc && ( !isset( $maxTocLevel ) || $toclevel < $maxTocLevel ) ) {
                $toc .= Linker::tocLine(
                    $linkAnchor,
                    $tocline,
                    $numbering,
                    $toclevel,
                    ( $isTemplate ? false : $sectionIndex )
                );
            }
 
            # Add the section to the section tree
            # Find the DOM node for this header
            $noOffset = ( $isTemplate || $sectionIndex === false );
            while ( $node && !$noOffset ) {
                if ( $node->getName() === 'h' ) {
                    $bits = $node->splitHeading();
                    if ( $bits['i'] == $sectionIndex ) {
                        break;
                    }
                }
                $byteOffset += mb_strlen(
                    $this->mStripState->unstripBoth(
                        $frame->expand( $node, PPFrame::RECOVER_ORIG )
                    )
                );
                $node = $node->getNextSibling();
            }
            $tocraw[] = [
                'toclevel' => $toclevel,
                'level' => $level,
                'line' => $tocline,
                'number' => $numbering,
                'index' => ( $isTemplate ? 'T-' : '' ) . $sectionIndex,
                'fromtitle' => $titleText,
                'byteoffset' => ( $noOffset ? null : $byteOffset ),
                'anchor' => $anchor,
            ];
 
            # give headline the correct <h#> tag
            if ( $maybeShowEditLink && $sectionIndex !== false ) {
                // Output edit section links as markers with styles that can be customized by skins
                if ( $isTemplate ) {
                    # Put a T flag in the section identifier, to indicate to extractSections()
                    # that sections inside <includeonly> should be counted.
                    $editsectionPage = $titleText;
                    $editsectionSection = "T-$sectionIndex";
                    $editsectionContent = null;
                } else {
                    $editsectionPage = $this->getTitle()->getPrefixedText();
                    $editsectionSection = $sectionIndex;
                    $editsectionContent = $headlineHint;
                }
                // We use a bit of pesudo-xml for editsection markers. The
                // language converter is run later on. Using a UNIQ style marker
                // leads to the converter screwing up the tokens when it
                // converts stuff. And trying to insert strip tags fails too. At
                // this point all real inputted tags have already been escaped,
                // so we don't have to worry about a user trying to input one of
                // these markers directly. We use a page and section attribute
                // to stop the language converter from converting these
                // important bits of data, but put the headline hint inside a
                // content block because the language converter is supposed to
                // be able to convert that piece of data.
                // Gets replaced with html in ParserOutput::getText
                $editlink = '<mw:editsection page="' . htmlspecialchars( $editsectionPage );
                // @phan-suppress-next-line SecurityCheck-DoubleEscaped
                $editlink .= '" section="' . htmlspecialchars( $editsectionSection ) . '"';
                if ( $editsectionContent !== null ) {
                    $editlink .= '>' . $editsectionContent . '</mw:editsection>';
                } else {
                    $editlink .= '/>';
                }
            } else {
                $editlink = '';
            }
            $head[$headlineCount] = Linker::makeHeadline(
                $level,
                $matches['attrib'][$headlineCount],
                $anchor,
                $headline,
                $editlink,
                $fallbackAnchor
            );
 
            $headlineCount++;
        }
 
        $this->setOutputType( $oldType );
 
        # Never ever show TOC if no headers
        if ( $numVisible < 1 ) {
            $enoughToc = false;
        }
 
        if ( $enoughToc ) {
            if ( $prevtoclevel > 0 && $prevtoclevel < $maxTocLevel ) {
                $toc .= Linker::tocUnindent( $prevtoclevel - 1 );
            }
            $toc = Linker::tocList( $toc, $this->mOptions->getUserLangObj() );
            $this->mOutput->setTOCHTML( $toc );
        }
 
        if ( $isMain ) {
            $this->mOutput->setSections( $tocraw );
        }
 
        # split up and insert constructed headlines
        $blocks = preg_split( '/<H[1-6].*?>[\s\S]*?<\/H[1-6]>/i', $text );
        $i = 0;
 
        // build an array of document sections
        $sections = [];
        foreach ( $blocks as $block ) {
            // $head is zero-based, sections aren't.
            if ( empty( $head[$i - 1] ) ) {
                $sections[$i] = $block;
            } else {
                $sections[$i] = $head[$i - 1] . $block;
            }
 
            $this->hookRunner->onParserSectionCreate( $this, $i, $sections[$i], $maybeShowEditLink );
 
            $i++;
        }
 
        if ( $enoughToc && $isMain && !$this->mForceTocPosition ) {
            // append the TOC at the beginning
            // Top anchor now in skin
            $sections[0] .= self::TOC_PLACEHOLDER . "\n";
        }
 
        $full .= implode( '', $sections );
 
        return $full;
    }
 
    public function preSaveTransform(
        $text,
        PageReference $page,
        UserIdentity $user,
        ParserOptions $options,
        $clearState = true
    ) {
        if ( $clearState ) {
            $magicScopeVariable = $this->lock();
        }
        $this->startParse( $page, $options, self::OT_WIKI, $clearState );
        $this->setUser( $user );
 
        // Strip U+0000 NULL (T159174)
        $text = str_replace( "\000", '', $text );
 
        // We still normalize line endings (including trimming trailing whitespace) for
        // backwards-compatibility with other code that just calls PST, but this should already
        // be handled in TextContent subclasses
        $text = TextContent::normalizeLineEndings( $text );
 
        if ( $options->getPreSaveTransform() ) {
            $text = $this->pstPass2( $text, $user );
        }
        $text = $this->mStripState->unstripBoth( $text );
 
        // Trim trailing whitespace again, because the previous steps can introduce it.
        $text = rtrim( $text );
 
        $this->hookRunner->onParserPreSaveTransformComplete( $this, $text );
 
        $this->setUser( null ); # Reset
 
        return $text;
    }
 
    private function pstPass2( $text, UserIdentity $user ) {
        # Note: This is the timestamp saved as hardcoded wikitext to the database, we use
        # $this->contLang here in order to give everyone the same signature and use the default one
        # rather than the one selected in each user's preferences.  (see also T14815)
        $ts = $this->mOptions->getTimestamp();
        $timestamp = MWTimestamp::getLocalInstance( $ts );
        $ts = $timestamp->format( 'YmdHis' );
        $tzMsg = $timestamp->getTimezoneMessage()->inContentLanguage()->text();
 
        $d = $this->contLang->timeanddate( $ts, false, false ) . " ($tzMsg)";
 
        # Variable replacement
        # Because mOutputType is OT_WIKI, this will only process {{subst:xxx}} type tags
        $text = $this->replaceVariables( $text );
 
        # This works almost by chance, as the replaceVariables are done before the getUserSig(),
        # which may corrupt this parser instance via its wfMessage()->text() call-
 
        # Signatures
        if ( strpos( $text, '~~~' ) !== false ) {
            $sigText = $this->getUserSig( $user );
            $text = strtr( $text, [
                '~~~~~' => $d,
                '~~~~' => "$sigText $d",
                '~~~' => $sigText
            ] );
            # The main two signature forms used above are time-sensitive
            $this->setOutputFlag( ParserOutputFlags::USER_SIGNATURE, 'User signature detected' );
        }
 
        # Context links ("pipe tricks"): [[|name]] and [[name (context)|]]
        $tc = '[' . Title::legalChars() . ']';
        $nc = '[ _0-9A-Za-z\x80-\xff-]'; # Namespaces can use non-ascii!
 
        // [[ns:page (context)|]]
        $p1 = "/\[\[(:?$nc+:|:|)($tc+?)( ?\\($tc+\\))\\|]]/";
        // [[ns:page（context）|]] (double-width brackets, added in r40257)
        $p4 = "/\[\[(:?$nc+:|:|)($tc+?)( ?（$tc+）)\\|]]/";
        // [[ns:page (context), context|]] (using single, double-width or Arabic comma)
        $p3 = "/\[\[(:?$nc+:|:|)($tc+?)( ?\\($tc+\\)|)((?:, |，|، )$tc+|)\\|]]/";
        // [[|page]] (reverse pipe trick: add context from page title)
        $p2 = "/\[\[\\|($tc+)]]/";
 
        # try $p1 first, to turn "[[A, B (C)|]]" into "[[A, B (C)|A, B]]"
        $text = preg_replace( $p1, '[[\\1\\2\\3|\\2]]', $text );
        $text = preg_replace( $p4, '[[\\1\\2\\3|\\2]]', $text );
        $text = preg_replace( $p3, '[[\\1\\2\\3\\4|\\2]]', $text );
 
        $t = $this->getTitle()->getText();
        $m = [];
        if ( preg_match( "/^($nc+:|)$tc+?( \\($tc+\\))$/", $t, $m ) ) {
            $text = preg_replace( $p2, "[[$m[1]\\1$m[2]|\\1]]", $text );
        } elseif ( preg_match( "/^($nc+:|)$tc+?(, $tc+|)$/", $t, $m ) && "$m[1]$m[2]" != '' ) {
            $text = preg_replace( $p2, "[[$m[1]\\1$m[2]|\\1]]", $text );
        } else {
            # if there's no context, don't bother duplicating the title
            $text = preg_replace( $p2, '[[\\1]]', $text );
        }
 
        return $text;
    }
 
    public function getUserSig( UserIdentity $user, $nickname = false, $fancySig = null ) {
        $username = $user->getName();
 
        # If not given, retrieve from the user object.
        if ( $nickname === false ) {
            $nickname = $this->userOptionsLookup->getOption( $user, 'nickname' );
        }
 
        if ( $fancySig === null ) {
            $fancySig = $this->userOptionsLookup->getBoolOption( $user, 'fancysig' );
        }
 
        if ( $nickname === null || $nickname === '' ) {
            // Empty value results in the default signature (even when fancysig is enabled)
            $nickname = $username;
        } elseif ( mb_strlen( $nickname ) > $this->svcOptions->get( 'MaxSigChars' ) ) {
            $nickname = $username;
            $this->logger->debug( __METHOD__ . ": $username has overlong signature." );
        } elseif ( $fancySig !== false ) {
            # Sig. might contain markup; validate this
            $isValid = $this->validateSig( $nickname ) !== false;
 
            # New validator
            $sigValidation = $this->svcOptions->get( 'SignatureValidation' );
            if ( $isValid && $sigValidation === 'disallow' ) {
                $services = MediaWikiServices::getInstance();
                $parserOpts = $services->getParser()->getOptions();
                $validator = $services->getSignatureValidatorFactory()
                    ->newSignatureValidator( $user, null, $parserOpts );
                $isValid = !$validator->validateSignature( $nickname );
            }
 
            if ( $isValid ) {
                # Validated; clean up (if needed) and return it
                return $this->cleanSig( $nickname, true );
            } else {
                # Failed to validate; fall back to the default
                $nickname = $username;
                $this->logger->debug( __METHOD__ . ": $username has invalid signature." );
            }
        }
 
        # Make sure nickname doesnt get a sig in a sig
        $nickname = self::cleanSigInSig( $nickname );
 
        # If we're still here, make it a link to the user page
        $userText = wfEscapeWikiText( $username );
        $nickText = wfEscapeWikiText( $nickname );
        $msgName = $user->isRegistered() ? 'signature' : 'signature-anon';
 
        return wfMessage( $msgName, $userText, $nickText )->inContentLanguage()
            ->page( $this->getPage() )->text();
    }
 
    public function validateSig( $text ) {
        return Xml::isWellFormedXmlFragment( $text ) ? $text : false;
    }
 
    public function cleanSig( $text, $parsing = false ) {
        if ( !$parsing ) {
            global $wgTitle;
            $magicScopeVariable = $this->lock();
            $this->startParse(
                $wgTitle,
                ParserOptions::newFromUser( RequestContext::getMain()->getUser() ),
                self::OT_PREPROCESS,
                true
            );
        }
 
        # Option to disable this feature
        if ( !$this->mOptions->getCleanSignatures() ) {
            return $text;
        }
 
        # @todo FIXME: Regex doesn't respect extension tags or nowiki
        #  => Move this logic to braceSubstitution()
        $substWord = $this->magicWordFactory->get( 'subst' );
        $substRegex = '/\{\{(?!(?:' . $substWord->getBaseRegex() . '))/x' . $substWord->getRegexCase();
        $substText = '{{' . $substWord->getSynonym( 0 );
 
        $text = preg_replace( $substRegex, $substText, $text );
        $text = self::cleanSigInSig( $text );
        $dom = $this->preprocessToDom( $text );
        $frame = $this->getPreprocessor()->newFrame();
        $text = $frame->expand( $dom );
 
        if ( !$parsing ) {
            $text = $this->mStripState->unstripBoth( $text );
        }
 
        return $text;
    }
 
    public static function cleanSigInSig( $text ) {
        $text = preg_replace( '/~{3,5}/', '', $text );
        return $text;
    }
 
    public static function replaceTableOfContentsMarker( $text, $toc ) {
        return str_replace(
            self::TOC_PLACEHOLDER,
            $toc,
            $text
        );
    }
 
    public function startExternalParse( ?PageReference $page, ParserOptions $options,
        $outputType, $clearState = true, $revId = null
    ) {
        $this->startParse( $page, $options, $outputType, $clearState );
        if ( $revId !== null ) {
            $this->mRevisionId = $revId;
        }
    }
 
    private function startParse( ?PageReference $page, ParserOptions $options,
        $outputType, $clearState = true
    ) {
        $this->setPage( $page );
        $this->mOptions = $options;
        $this->setOutputType( $outputType );
        if ( $clearState ) {
            $this->clearState();
        }
    }
 
    public function transformMsg( $text, ParserOptions $options, ?PageReference $page = null ) {
        static $executing = false;
 
        # Guard against infinite recursion
        if ( $executing ) {
            return $text;
        }
        $executing = true;
 
        if ( !$page ) {
            global $wgTitle;
            $page = $wgTitle;
        }
 
        $text = $this->preprocess( $text, $page, $options );
 
        $executing = false;
        return $text;
    }
 
    public function setHook( $tag, callable $callback ) {
        $tag = strtolower( $tag );
        if ( preg_match( '/[<>\r\n]/', $tag, $m ) ) {
            throw new MWException( "Invalid character {$m[0]} in setHook('$tag', ...) call" );
        }
        $oldVal = $this->mTagHooks[$tag] ?? null;
        $this->mTagHooks[$tag] = $callback;
        if ( !in_array( $tag, $this->mStripList ) ) {
            $this->mStripList[] = $tag;
        }
 
        return $oldVal;
    }
 
    public function clearTagHooks() {
        $this->mTagHooks = [];
        $this->mStripList = [];
    }
 
    public function setFunctionHook( $id, callable $callback, $flags = 0 ) {
        $oldVal = $this->mFunctionHooks[$id][0] ?? null;
        $this->mFunctionHooks[$id] = [ $callback, $flags ];
 
        # Add to function cache
        $mw = $this->magicWordFactory->get( $id );
        if ( !$mw ) {
            throw new MWException( __METHOD__ . '() expecting a magic word identifier.' );
        }
 
        $synonyms = $mw->getSynonyms();
        $sensitive = intval( $mw->isCaseSensitive() );
 
        foreach ( $synonyms as $syn ) {
            # Case
            if ( !$sensitive ) {
                $syn = $this->contLang->lc( $syn );
            }
            # Add leading hash
            if ( !( $flags & self::SFH_NO_HASH ) ) {
                $syn = '#' . $syn;
            }
            # Remove trailing colon
            if ( substr( $syn, -1, 1 ) === ':' ) {
                $syn = substr( $syn, 0, -1 );
            }
            $this->mFunctionSynonyms[$sensitive][$syn] = $id;
        }
        return $oldVal;
    }
 
    public function getFunctionHooks() {
        return array_keys( $this->mFunctionHooks );
    }
 
    public function replaceLinkHolders( &$text, $options = 0 ) {
        $this->replaceLinkHoldersPrivate( $text, $options );
    }
 
    private function replaceLinkHoldersPrivate( &$text, $options = 0 ) {
        $this->mLinkHolders->replace( $text );
    }
 
    private function replaceLinkHoldersText( $text ) {
        return $this->mLinkHolders->replaceText( $text );
    }
 
    public function renderImageGallery( $text, array $params ) {
        $mode = false;
        if ( isset( $params['mode'] ) ) {
            $mode = $params['mode'];
        }
 
        try {
            $ig = ImageGalleryBase::factory( $mode );
        } catch ( Exception $e ) {
            // If invalid type set, fallback to default.
            $ig = ImageGalleryBase::factory( false );
        }
 
        $ig->setContextTitle( $this->getTitle() );
        $ig->setShowBytes( false );
        $ig->setShowDimensions( false );
        $ig->setShowFilename( false );
        $ig->setParser( $this );
        $ig->setHideBadImages();
        $ig->setAttributes( Sanitizer::validateTagAttributes( $params, 'ul' ) );
 
        if ( isset( $params['showfilename'] ) ) {
            $ig->setShowFilename( true );
        } else {
            $ig->setShowFilename( false );
        }
        if ( isset( $params['caption'] ) ) {
            // NOTE: We aren't passing a frame here or below.  Frame info
            // is currently opaque to Parsoid, which acts on OT_PREPROCESS.
            // See T107332#4030581
            $caption = $this->recursiveTagParse( $params['caption'] );
            $ig->setCaptionHtml( $caption );
        }
        if ( isset( $params['perrow'] ) ) {
            $ig->setPerRow( $params['perrow'] );
        }
        if ( isset( $params['widths'] ) ) {
            $ig->setWidths( $params['widths'] );
        }
        if ( isset( $params['heights'] ) ) {
            $ig->setHeights( $params['heights'] );
        }
        $ig->setAdditionalOptions( $params );
 
        $this->hookRunner->onBeforeParserrenderImageGallery( $this, $ig );
 
        $lines = StringUtils::explode( "\n", $text );
        foreach ( $lines as $line ) {
            # match lines like these:
            # Image:someimage.jpg|This is some image
            $matches = [];
            preg_match( "/^([^|]+)(\\|(.*))?$/", $line, $matches );
            # Skip empty lines
            if ( count( $matches ) == 0 ) {
                continue;
            }
 
            if ( strpos( $matches[0], '%' ) !== false ) {
                $matches[1] = rawurldecode( $matches[1] );
            }
            $title = Title::newFromText( $matches[1], NS_FILE );
            if ( $title === null ) {
                # Bogus title. Ignore these so we don't bomb out later.
                continue;
            }
 
            # We need to get what handler the file uses, to figure out parameters.
            # Note, a hook can overide the file name, and chose an entirely different
            # file (which potentially could be of a different type and have different handler).
            $options = [];
            $descQuery = false;
            $this->hookRunner->onBeforeParserFetchFileAndTitle(
                $this, $title, $options, $descQuery );
            # Don't register it now, as TraditionalImageGallery does that later.
            $file = $this->fetchFileNoRegister( $title, $options );
            $handler = $file ? $file->getHandler() : false;
 
            $paramMap = [
                'img_alt' => 'gallery-internal-alt',
                'img_link' => 'gallery-internal-link',
            ];
            if ( $handler ) {
                $paramMap += $handler->getParamMap();
                // We don't want people to specify per-image widths.
                // Additionally the width parameter would need special casing anyhow.
                unset( $paramMap['img_width'] );
            }
 
            $mwArray = $this->magicWordFactory->newArray( array_keys( $paramMap ) );
 
            $label = '';
            $alt = '';
            $link = '';
            $handlerOptions = [];
            if ( isset( $matches[3] ) ) {
                // look for an |alt= definition while trying not to break existing
                // captions with multiple pipes (|) in it, until a more sensible grammar
                // is defined for images in galleries
 
                // FIXME: Doing recursiveTagParse at this stage, and the trim before
                // splitting on '|' is a bit odd, and different from makeImage.
                $matches[3] = $this->recursiveTagParse( trim( $matches[3] ) );
                // Protect LanguageConverter markup
                $parameterMatches = StringUtils::delimiterExplode(
                    '-{', '}-',
                    '|',
                    $matches[3],
                    true /* nested */
                );
 
                foreach ( $parameterMatches as $parameterMatch ) {
                    list( $magicName, $match ) = $mwArray->matchVariableStartToEnd( $parameterMatch );
                    if ( !$magicName ) {
                        // Last pipe wins.
                        $label = $parameterMatch;
                        continue;
                    }
 
                    $paramName = $paramMap[$magicName];
                    switch ( $paramName ) {
                        case 'gallery-internal-alt':
                            $alt = $this->stripAltText( $match, false );
                            break;
                        case 'gallery-internal-link':
                            $linkValue = $this->stripAltText( $match, false );
                            if ( preg_match( '/^-{R\|(.*)}-$/', $linkValue ) ) {
                                // Result of LanguageConverter::markNoConversion
                                // invoked on an external link.
                                $linkValue = substr( $linkValue, 4, -2 );
                            }
                            list( $type, $target ) = $this->parseLinkParameter( $linkValue );
                            if ( $type === 'link-url' ) {
                                $link = $target;
                                $this->mOutput->addExternalLink( $target );
                            } elseif ( $type === 'link-title' ) {
                                $link = $target->getLinkURL();
                                $this->mOutput->addLink( $target );
                            }
                            break;
                        default:
                            // Must be a handler specific parameter.
                            if ( $handler->validateParam( $paramName, $match ) ) {
                                $handlerOptions[$paramName] = $match;
                            } else {
                                // Guess not, consider it as caption.
                                $this->logger->debug(
                                    "$parameterMatch failed parameter validation" );
                                $label = $parameterMatch;
                            }
                    }
                }
            }
 
            $ig->add( $title, $label, $alt, $link, $handlerOptions );
        }
        $html = $ig->toHTML();
        $this->hookRunner->onAfterParserFetchFileAndTitle( $this, $ig, $html );
        return $html;
    }
 
    private function getImageParams( $handler ) {
        if ( $handler ) {
            $handlerClass = get_class( $handler );
        } else {
            $handlerClass = '';
        }
        if ( !isset( $this->mImageParams[$handlerClass] ) ) {
            # Initialise static lists
            static $internalParamNames = [
                'horizAlign' => [ 'left', 'right', 'center', 'none' ],
                'vertAlign' => [ 'baseline', 'sub', 'super', 'top', 'text-top', 'middle',
                    'bottom', 'text-bottom' ],
                'frame' => [ 'thumbnail', 'manualthumb', 'framed', 'frameless',
                    'upright', 'border', 'link', 'alt', 'class' ],
            ];
            static $internalParamMap;
            if ( !$internalParamMap ) {
                $internalParamMap = [];
                foreach ( $internalParamNames as $type => $names ) {
                    foreach ( $names as $name ) {
                        // For grep: img_left, img_right, img_center, img_none,
                        // img_baseline, img_sub, img_super, img_top, img_text_top, img_middle,
                        // img_bottom, img_text_bottom,
                        // img_thumbnail, img_manualthumb, img_framed, img_frameless, img_upright,
                        // img_border, img_link, img_alt, img_class
                        $magicName = str_replace( '-', '_', "img_$name" );
                        $internalParamMap[$magicName] = [ $type, $name ];
                    }
                }
            }
 
            # Add handler params
            $paramMap = $internalParamMap;
            if ( $handler ) {
                $handlerParamMap = $handler->getParamMap();
                foreach ( $handlerParamMap as $magic => $paramName ) {
                    $paramMap[$magic] = [ 'handler', $paramName ];
                }
            } else {
                // Parse the size for non-existent files.  See T273013
                $paramMap[ 'img_width' ] = [ 'handler', 'width' ];
            }
            $this->mImageParams[$handlerClass] = $paramMap;
            $this->mImageParamsMagicArray[$handlerClass] =
                $this->magicWordFactory->newArray( array_keys( $paramMap ) );
        }
        return [ $this->mImageParams[$handlerClass], $this->mImageParamsMagicArray[$handlerClass] ];
    }
 
    public function makeImage( LinkTarget $link, $options, $holders = false ) {
        # Check if the options text is of the form "options|alt text"
        # Options are:
        #  * thumbnail  make a thumbnail with enlarge-icon and caption, alignment depends on lang
        #  * left       no resizing, just left align. label is used for alt= only
        #  * right      same, but right aligned
        #  * none       same, but not aligned
        #  * ___px      scale to ___ pixels width, no aligning. e.g. use in taxobox
        #  * center     center the image
        #  * frame      Keep original image size, no magnify-button.
        #  * framed     Same as "frame"
        #  * frameless  like 'thumb' but without a frame. Keeps user preferences for width
        #  * upright    reduce width for upright images, rounded to full __0 px
        #  * border     draw a 1px border around the image
        #  * alt        Text for HTML alt attribute (defaults to empty)
        #  * class      Set a class for img node
        #  * link       Set the target of the image link. Can be external, interwiki, or local
        # vertical-align values (no % or length right now):
        #  * baseline
        #  * sub
        #  * super
        #  * top
        #  * text-top
        #  * middle
        #  * bottom
        #  * text-bottom
 
        # Protect LanguageConverter markup when splitting into parts
        $parts = StringUtils::delimiterExplode(
            '-{', '}-', '|', $options, true /* allow nesting */
        );
 
        # Give extensions a chance to select the file revision for us
        $options = [];
        $descQuery = false;
        $title = Title::castFromLinkTarget( $link ); // hook signature compat
        $this->hookRunner->onBeforeParserFetchFileAndTitle(
            $this, $title, $options, $descQuery );
        # Fetch and register the file (file title may be different via hooks)
        list( $file, $link ) = $this->fetchFileAndTitle( $link, $options );
 
        # Get parameter map
        $handler = $file ? $file->getHandler() : false;
 
        list( $paramMap, $mwArray ) = $this->getImageParams( $handler );
 
        if ( !$file ) {
            $this->addTrackingCategory( 'broken-file-category' );
        }
 
        # Process the input parameters
        $caption = '';
        $params = [ 'frame' => [], 'handler' => [],
            'horizAlign' => [], 'vertAlign' => [] ];
        $seenformat = false;
        foreach ( $parts as $part ) {
            $part = trim( $part );
            list( $magicName, $value ) = $mwArray->matchVariableStartToEnd( $part );
            $validated = false;
            if ( isset( $paramMap[$magicName] ) ) {
                list( $type, $paramName ) = $paramMap[$magicName];
 
                # Special case; width and height come in one variable together
                if ( $type === 'handler' && $paramName === 'width' ) {
                    $parsedWidthParam = self::parseWidthParam( $value );
                    // Parsoid applies data-(width|height) attributes to broken
                    // media spans, for client use.  See T273013
                    $validateFunc = static function ( $name, $value ) use ( $handler ) {
                        return $handler
                            ? $handler->validateParam( $name, $value )
                            : $value > 0;
                    };
                    if ( isset( $parsedWidthParam['width'] ) ) {
                        $width = $parsedWidthParam['width'];
                        if ( $validateFunc( 'width', $width ) ) {
                            $params[$type]['width'] = $width;
                            $validated = true;
                        }
                    }
                    if ( isset( $parsedWidthParam['height'] ) ) {
                        $height = $parsedWidthParam['height'];
                        if ( $validateFunc( 'height', $height ) ) {
                            $params[$type]['height'] = $height;
                            $validated = true;
                        }
                    }
                    # else no validation -- T15436
                } else {
                    if ( $type === 'handler' ) {
                        # Validate handler parameter
                        $validated = $handler->validateParam( $paramName, $value );
                    } else {
                        # Validate internal parameters
                        switch ( $paramName ) {
                            case 'manualthumb':
                            case 'alt':
                            case 'class':
                                # @todo FIXME: Possibly check validity here for
                                # manualthumb? downstream behavior seems odd with
                                # missing manual thumbs.
                                $validated = true;
                                $value = $this->stripAltText( $value, $holders );
                                break;
                            case 'link':
                                list( $paramName, $value ) =
                                    $this->parseLinkParameter(
                                        $this->stripAltText( $value, $holders )
                                    );
                                if ( $paramName ) {
                                    $validated = true;
                                    if ( $paramName === 'no-link' ) {
                                        $value = true;
                                    }
                                    if ( ( $paramName === 'link-url' ) && $this->mOptions->getExternalLinkTarget() ) {
                                        $params[$type]['link-target'] = $this->mOptions->getExternalLinkTarget();
                                    }
                                }
                                break;
                            case 'frameless':
                            case 'framed':
                            case 'thumbnail':
                                // use first appearing option, discard others.
                                $validated = !$seenformat;
                                $seenformat = true;
                                break;
                            default:
                                # Most other things appear to be empty or numeric...
                                $validated = ( $value === false || is_numeric( trim( $value ) ) );
                        }
                    }
 
                    if ( $validated ) {
                        $params[$type][$paramName] = $value;
                    }
                }
            }
            if ( !$validated ) {
                $caption = $part;
            }
        }
 
        # Process alignment parameters
        if ( $params['horizAlign'] ) {
            $params['frame']['align'] = key( $params['horizAlign'] );
        }
        if ( $params['vertAlign'] ) {
            $params['frame']['valign'] = key( $params['vertAlign'] );
        }
 
        $params['frame']['caption'] = $caption;
 
        # Will the image be presented in a frame, with the caption below?
        $imageIsFramed = isset( $params['frame']['frame'] )
            || isset( $params['frame']['framed'] )
            || isset( $params['frame']['thumbnail'] )
            || isset( $params['frame']['manualthumb'] );
 
        # In the old days, [[Image:Foo|text...]] would set alt text.  Later it
        # came to also set the caption, ordinary text after the image -- which
        # makes no sense, because that just repeats the text multiple times in
        # screen readers.  It *also* came to set the title attribute.
        # Now that we have an alt attribute, we should not set the alt text to
        # equal the caption: that's worse than useless, it just repeats the
        # text.  This is the framed/thumbnail case.  If there's no caption, we
        # use the unnamed parameter for alt text as well, just for the time be-
        # ing, if the unnamed param is set and the alt param is not.
        # For the future, we need to figure out if we want to tweak this more,
        # e.g., introducing a title= parameter for the title; ignoring the un-
        # named parameter entirely for images without a caption; adding an ex-
        # plicit caption= parameter and preserving the old magic unnamed para-
        # meter for BC; ...
        if ( $imageIsFramed ) { # Framed image
            if ( $caption === '' && !isset( $params['frame']['alt'] ) ) {
                # No caption or alt text, add the filename as the alt text so
                # that screen readers at least get some description of the image
                $params['frame']['alt'] = $link->getText();
            }
            # Do not set $params['frame']['title'] because tooltips don't make sense
            # for framed images
        } else { # Inline image
            if ( !isset( $params['frame']['alt'] ) ) {
                # No alt text, use the "caption" for the alt text
                if ( $caption !== '' ) {
                    $params['frame']['alt'] = $this->stripAltText( $caption, $holders );
                } else {
                    # No caption, fall back to using the filename for the
                    # alt text
                    $params['frame']['alt'] = $link->getText();
                }
            }
            # Use the "caption" for the tooltip text
            $params['frame']['title'] = $this->stripAltText( $caption, $holders );
        }
        $params['handler']['targetlang'] = $this->getTargetLanguage()->getCode();
 
        // hook signature compat again, $link may have changed
        $title = Title::castFromLinkTarget( $link );
        $this->hookRunner->onParserMakeImageParams( $title, $file, $params, $this );
 
        # Linker does the rest
        $time = $options['time'] ?? false;
        $ret = Linker::makeImageLink( $this, $link, $file, $params['frame'], $params['handler'],
            $time, $descQuery, $this->mOptions->getThumbSize() );
 
        # Give the handler a chance to modify the parser object
        if ( $handler ) {
            $handler->parserTransformHook( $this, $file );
        }
        if ( $file ) {
            $this->modifyImageHtml( $file, $params, $ret );
        }
 
        return $ret;
    }
 
    private function parseLinkParameter( $value ) {
        $chars = self::EXT_LINK_URL_CLASS;
        $addr = self::EXT_LINK_ADDR;
        $prots = $this->mUrlProtocols;
        $type = null;
        $target = false;
        if ( $value === '' ) {
            $type = 'no-link';
        } elseif ( preg_match( "/^((?i)$prots)/", $value ) ) {
            if ( preg_match( "/^((?i)$prots)$addr$chars*$/u", $value, $m ) ) {
                $this->mOutput->addExternalLink( $value );
                $type = 'link-url';
                $target = $value;
            }
        } else {
            $linkTitle = Title::newFromText( $value );
            if ( $linkTitle ) {
                $this->mOutput->addLink( $linkTitle );
                $type = 'link-title';
                $target = $linkTitle;
            }
        }
        return [ $type, $target ];
    }
 
    public function modifyImageHtml( File $file, array $params, string &$html ) {
        $this->hookRunner->onParserModifyImageHTML( $this, $file, $params, $html );
    }
 
    private function stripAltText( $caption, $holders ) {
        # Strip bad stuff out of the title (tooltip).  We can't just use
        # replaceLinkHoldersText() here, because if this function is called
        # from handleInternalLinks2(), mLinkHolders won't be up-to-date.
        if ( $holders ) {
            $tooltip = $holders->replaceText( $caption );
        } else {
            $tooltip = $this->replaceLinkHoldersText( $caption );
        }
 
        # make sure there are no placeholders in thumbnail attributes
        # that are later expanded to html- so expand them now and
        # remove the tags
        $tooltip = $this->mStripState->unstripBoth( $tooltip );
        # Compatibility hack!  In HTML certain entity references not terminated
        # by a semicolon are decoded (but not if we're in an attribute; that's
        # how link URLs get away without properly escaping & in queries).
        # But wikitext has always required semicolon-termination of entities,
        # so encode & where needed to avoid decode of semicolon-less entities.
        # See T209236 and
        # https://www.w3.org/TR/html5/syntax.html#named-character-references
        # T210437 discusses moving this workaround to Sanitizer::stripAllTags.
        $tooltip = preg_replace( "/
            &           # 1. entity prefix
            (?=         # 2. followed by:
            (?:         #  a. one of the legacy semicolon-less named entities
                A(?:Elig|MP|acute|circ|grave|ring|tilde|uml)|
                C(?:OPY|cedil)|E(?:TH|acute|circ|grave|uml)|
                GT|I(?:acute|circ|grave|uml)|LT|Ntilde|
                O(?:acute|circ|grave|slash|tilde|uml)|QUOT|REG|THORN|
                U(?:acute|circ|grave|uml)|Yacute|
                a(?:acute|c(?:irc|ute)|elig|grave|mp|ring|tilde|uml)|brvbar|
                c(?:cedil|edil|urren)|cent(?!erdot;)|copy(?!sr;)|deg|
                divide(?!ontimes;)|e(?:acute|circ|grave|th|uml)|
                frac(?:1(?:2|4)|34)|
                gt(?!c(?:c|ir)|dot|lPar|quest|r(?:a(?:pprox|rr)|dot|eq(?:less|qless)|less|sim);)|
                i(?:acute|circ|excl|grave|quest|uml)|laquo|
                lt(?!c(?:c|ir)|dot|hree|imes|larr|quest|r(?:Par|i(?:e|f|));)|
                m(?:acr|i(?:cro|ddot))|n(?:bsp|tilde)|
                not(?!in(?:E|dot|v(?:a|b|c)|)|ni(?:v(?:a|b|c)|);)|
                o(?:acute|circ|grave|rd(?:f|m)|slash|tilde|uml)|
                p(?:lusmn|ound)|para(?!llel;)|quot|r(?:aquo|eg)|
                s(?:ect|hy|up(?:1|2|3)|zlig)|thorn|times(?!b(?:ar|)|d;)|
                u(?:acute|circ|grave|ml|uml)|y(?:acute|en|uml)
            )
            (?:[^;]|$)) #  b. and not followed by a semicolon
            # S = study, for efficiency
            /Sx", '&amp;', $tooltip );
        $tooltip = Sanitizer::stripAllTags( $tooltip );
 
        return $tooltip;
    }
 
    public function attributeStripCallback( &$text, $frame = false ) {
        wfDeprecated( __METHOD__, '1.35' );
        $text = $this->replaceVariables( $text, $frame );
        $text = $this->mStripState->unstripBoth( $text );
        return $text;
    }
 
    public function getTags() {
        return array_keys( $this->mTagHooks );
    }
 
    public function getFunctionSynonyms() {
        return $this->mFunctionSynonyms;
    }
 
    public function getUrlProtocols() {
        return $this->mUrlProtocols;
    }
 
    private function extractSections( $text, $sectionId, $mode, $newText = '' ) {
        global $wgTitle; # not generally used but removes an ugly failure mode
 
        $magicScopeVariable = $this->lock();
        $this->startParse(
            $wgTitle,
            ParserOptions::newFromUser( RequestContext::getMain()->getUser() ),
            self::OT_PLAIN,
            true
        );
        $outText = '';
        $frame = $this->getPreprocessor()->newFrame();
 
        # Process section extraction flags
        $flags = 0;
        $sectionParts = explode( '-', $sectionId );
        $sectionIndex = array_pop( $sectionParts );
        foreach ( $sectionParts as $part ) {
            if ( $part === 'T' ) {
                $flags |= Preprocessor::DOM_FOR_INCLUSION;
            }
        }
 
        # Check for empty input
        if ( strval( $text ) === '' ) {
            # Only sections 0 and T-0 exist in an empty document
            if ( $sectionIndex == 0 ) {
                if ( $mode === 'get' ) {
                    return '';
                }
 
                return $newText;
            } else {
                if ( $mode === 'get' ) {
                    return $newText;
                }
 
                return $text;
            }
        }
 
        # Preprocess the text
        $root = $this->preprocessToDom( $text, $flags );
 
        # <h> nodes indicate section breaks
        # They can only occur at the top level, so we can find them by iterating the root's children
        $node = $root->getFirstChild();
 
        # Find the target section
        if ( $sectionIndex == 0 ) {
            # Section zero doesn't nest, level=big
            $targetLevel = 1000;
        } else {
            while ( $node ) {
                if ( $node->getName() === 'h' ) {
                    $bits = $node->splitHeading();
                    if ( $bits['i'] == $sectionIndex ) {
                        $targetLevel = $bits['level'];
                        break;
                    }
                }
                if ( $mode === 'replace' ) {
                    $outText .= $frame->expand( $node, PPFrame::RECOVER_ORIG );
                }
                $node = $node->getNextSibling();
            }
        }
 
        if ( !$node ) {
            # Not found
            if ( $mode === 'get' ) {
                return $newText;
            } else {
                return $text;
            }
        }
 
        # Find the end of the section, including nested sections
        do {
            if ( $node->getName() === 'h' ) {
                $bits = $node->splitHeading();
                $curLevel = $bits['level'];
                if ( $bits['i'] != $sectionIndex && $curLevel <= $targetLevel ) {
                    break;
                }
            }
            if ( $mode === 'get' ) {
                $outText .= $frame->expand( $node, PPFrame::RECOVER_ORIG );
            }
            $node = $node->getNextSibling();
        } while ( $node );
 
        # Write out the remainder (in replace mode only)
        if ( $mode === 'replace' ) {
            # Output the replacement text
            # Add two newlines on -- trailing whitespace in $newText is conventionally
            # stripped by the editor, so we need both newlines to restore the paragraph gap
            # Only add trailing whitespace if there is newText
            if ( $newText != "" ) {
                $outText .= $newText . "\n\n";
            }
 
            while ( $node ) {
                $outText .= $frame->expand( $node, PPFrame::RECOVER_ORIG );
                $node = $node->getNextSibling();
            }
        }
 
        # Re-insert stripped tags
        $outText = rtrim( $this->mStripState->unstripBoth( $outText ) );
 
        return $outText;
    }
 
    public function getSection( $text, $sectionId, $defaultText = '' ) {
        return $this->extractSections( $text, $sectionId, 'get', $defaultText );
    }
 
    public function replaceSection( $oldText, $sectionId, $newText ) {
        return $this->extractSections( $oldText, $sectionId, 'replace', $newText );
    }
 
    public function getFlatSectionInfo( $text ) {
        $magicScopeVariable = $this->lock();
        $this->startParse(
            null,
            ParserOptions::newFromUser( RequestContext::getMain()->getUser() ),
            self::OT_PLAIN,
            true
        );
        $frame = $this->getPreprocessor()->newFrame();
        $root = $this->preprocessToDom( $text, 0 );
        $node = $root->getFirstChild();
        $offset = 0;
        $currentSection = [
            'index' => 0,
            'level' => 0,
            'offset' => 0,
            'heading' => '',
            'text' => ''
        ];
        $sections = [];
 
        while ( $node ) {
            $nodeText = $frame->expand( $node, PPFrame::RECOVER_ORIG );
            if ( $node->getName() === 'h' ) {
                $bits = $node->splitHeading();
                $sections[] = $currentSection;
                $currentSection = [
                    'index' => $bits['i'],
                    'level' => $bits['level'],
                    'offset' => $offset,
                    'heading' => $nodeText,
                    'text' => $nodeText
                ];
            } else {
                $currentSection['text'] .= $nodeText;
            }
            $offset += strlen( $nodeText );
            $node = $node->getNextSibling();
        }
        $sections[] = $currentSection;
        return $sections;
    }
 
    public function getRevisionId() {
        return $this->mRevisionId;
    }
 
    public function getRevisionRecordObject() {
        if ( $this->mRevisionRecordObject ) {
            return $this->mRevisionRecordObject;
        }
 
        // NOTE: try to get the RevisionRecord object even if mRevisionId is null.
        // This is useful when parsing a revision that has not yet been saved.
        // However, if we get back a saved revision even though we are in
        // preview mode, we'll have to ignore it, see below.
        // NOTE: This callback may be used to inject an OLD revision that was
        // already loaded, so "current" is a bit of a misnomer. We can't just
        // skip it if mRevisionId is set.
        $rev = call_user_func(
            $this->mOptions->getCurrentRevisionRecordCallback(),
            $this->getTitle(),
            $this
        );
 
        if ( $rev === false ) {
            // The revision record callback returns `false` (not null) to
            // indicate that the revision is missing.  (See for example
            // Parser::statelessFetchRevisionRecord(), the default callback.)
            // This API expects `null` instead. (T251952)
            $rev = null;
        }
 
        if ( $this->mRevisionId === null && $rev && $rev->getId() ) {
            // We are in preview mode (mRevisionId is null), and the current revision callback
            // returned an existing revision. Ignore it and return null, it's probably the page's
            // current revision, which is not what we want here. Note that we do want to call the
            // callback to allow the unsaved revision to be injected here, e.g. for
            // self-transclusion previews.
            return null;
        }
 
        // If the parse is for a new revision, then the callback should have
        // already been set to force the object and should match mRevisionId.
        // If not, try to fetch by mRevisionId instead.
        if ( $this->mRevisionId && $rev && $rev->getId() != $this->mRevisionId ) {
            $rev = MediaWikiServices::getInstance()
                ->getRevisionLookup()
                ->getRevisionById( $this->mRevisionId );
        }
 
        $this->mRevisionRecordObject = $rev;
 
        return $this->mRevisionRecordObject;
    }
 
    public function getRevisionTimestamp() {
        if ( $this->mRevisionTimestamp !== null ) {
            return $this->mRevisionTimestamp;
        }
 
        # Use specified revision timestamp, falling back to the current timestamp
        $revObject = $this->getRevisionRecordObject();
        $timestamp = $revObject ? $revObject->getTimestamp() : $this->mOptions->getTimestamp();
        $this->mOutput->setRevisionTimestampUsed( $timestamp ); // unadjusted time zone
 
        # The cryptic '' timezone parameter tells to use the site-default
        # timezone offset instead of the user settings.
        # Since this value will be saved into the parser cache, served
        # to other users, and potentially even used inside links and such,
        # it needs to be consistent for all visitors.
        $this->mRevisionTimestamp = $this->contLang->userAdjust( $timestamp, '' );
 
        return $this->mRevisionTimestamp;
    }
 
    public function getRevisionUser(): ?string {
        if ( $this->mRevisionUser === null ) {
            $revObject = $this->getRevisionRecordObject();
 
            # if this template is subst: the revision id will be blank,
            # so just use the current user's name
            if ( $revObject && $revObject->getUser() ) {
                $this->mRevisionUser = $revObject->getUser()->getName();
            } elseif ( $this->ot['wiki'] || $this->mOptions->getIsPreview() ) {
                $this->mRevisionUser = $this->getUserIdentity()->getName();
            } else {
                # Note that we fall through here with
                # $this->mRevisionUser still null
            }
        }
        return $this->mRevisionUser;
    }
 
    public function getRevisionSize() {
        if ( $this->mRevisionSize === null ) {
            $revObject = $this->getRevisionRecordObject();
 
            # if this variable is subst: the revision id will be blank,
            # so just use the parser input size, because the own substitution
            # will change the size.
            if ( $revObject ) {
                $this->mRevisionSize = $revObject->getSize();
            } else {
                $this->mRevisionSize = $this->mInputSize;
            }
        }
        return $this->mRevisionSize;
    }
 
    public function setDefaultSort( $sort ) {
        $this->mDefaultSort = $sort;
        $this->mOutput->setPageProperty( 'defaultsort', $sort );
    }
 
    public function getDefaultSort() {
        if ( $this->mDefaultSort !== false ) {
            return $this->mDefaultSort;
        } else {
            return '';
        }
    }
 
    public function getCustomDefaultSort() {
        return $this->mDefaultSort;
    }
 
    private static function getSectionNameFromStrippedText( $text ) {
        $text = Sanitizer::normalizeSectionNameWhitespace( $text );
        $text = Sanitizer::decodeCharReferences( $text );
        $text = self::normalizeSectionName( $text );
        return $text;
    }
 
    private static function makeAnchor( $sectionName ) {
        return '#' . Sanitizer::escapeIdForLink( $sectionName );
    }
 
    private function makeLegacyAnchor( $sectionName ) {
        $fragmentMode = $this->svcOptions->get( 'FragmentMode' );
        if ( isset( $fragmentMode[1] ) && $fragmentMode[1] === 'legacy' ) {
            // ForAttribute() and ForLink() are the same for legacy encoding
            $id = Sanitizer::escapeIdForAttribute( $sectionName, Sanitizer::ID_FALLBACK );
        } else {
            $id = Sanitizer::escapeIdForLink( $sectionName );
        }
 
        return "#$id";
    }
 
    public function guessSectionNameFromWikiText( $text ) {
        # Strip out wikitext links(they break the anchor)
        $text = $this->stripSectionName( $text );
        $sectionName = self::getSectionNameFromStrippedText( $text );
        return self::makeAnchor( $sectionName );
    }
 
    public function guessLegacySectionNameFromWikiText( $text ) {
        # Strip out wikitext links(they break the anchor)
        $text = $this->stripSectionName( $text );
        $sectionName = self::getSectionNameFromStrippedText( $text );
        return $this->makeLegacyAnchor( $sectionName );
    }
 
    public static function guessSectionNameFromStrippedText( $text ) {
        $sectionName = self::getSectionNameFromStrippedText( $text );
        return self::makeAnchor( $sectionName );
    }
 
    private static function normalizeSectionName( $text ) {
        # T90902: ensure the same normalization is applied for IDs as to links
 
        $titleParser = MediaWikiServices::getInstance()->getTitleParser();
        '@phan-var MediaWikiTitleCodec $titleParser';
        try {
 
            $parts = $titleParser->splitTitleString( "#$text" );
        } catch ( MalformedTitleException $ex ) {
            return $text;
        }
        return $parts['fragment'];
    }
 
    public function stripSectionName( $text ) {
        # Strip internal link markup
        $text = preg_replace( '/\[\[:?([^[|]+)\|([^[]+)\]\]/', '$2', $text );
        $text = preg_replace( '/\[\[:?([^[]+)\|?\]\]/', '$1', $text );
 
        # Strip external link markup
        # @todo FIXME: Not tolerant to blank link text
        # I.E. [https://www.mediawiki.org] will render as [1] or something depending
        # on how many empty links there are on the page - need to figure that out.
        $text = preg_replace( '/\[(?i:' . $this->mUrlProtocols . ')([^ ]+?) ([^[]+)\]/', '$2', $text );
 
        # Parse wikitext quotes (italics & bold)
        $text = $this->doQuotes( $text );
 
        # Strip HTML tags
        $text = StringUtils::delimiterReplace( '<', '>', '', $text );
        return $text;
    }
 
    private function fuzzTestSrvus( $text, PageReference $page, ParserOptions $options,
        $outputType = self::OT_HTML
    ) {
        $magicScopeVariable = $this->lock();
        $this->startParse( $page, $options, $outputType, true );
 
        $text = $this->replaceVariables( $text );
        $text = $this->mStripState->unstripBoth( $text );
        $text = Sanitizer::removeHTMLtags( $text );
        return $text;
    }
 
    private function fuzzTestPst( $text, PageReference $page, ParserOptions $options ) {
        return $this->preSaveTransform( $text, $page, $options->getUserIdentity(), $options );
    }
 
    private function fuzzTestPreprocess( $text, PageReference $page, ParserOptions $options ) {
        return $this->fuzzTestSrvus( $text, $page, $options, self::OT_PREPROCESS );
    }
 
    public function markerSkipCallback( $s, callable $callback ) {
        $i = 0;
        $out = '';
        while ( $i < strlen( $s ) ) {
            $markerStart = strpos( $s, self::MARKER_PREFIX, $i );
            if ( $markerStart === false ) {
                $out .= call_user_func( $callback, substr( $s, $i ) );
                break;
            } else {
                $out .= call_user_func( $callback, substr( $s, $i, $markerStart - $i ) );
                $markerEnd = strpos( $s, self::MARKER_SUFFIX, $markerStart );
                if ( $markerEnd === false ) {
                    $out .= substr( $s, $markerStart );
                    break;
                } else {
                    $markerEnd += strlen( self::MARKER_SUFFIX );
                    $out .= substr( $s, $markerStart, $markerEnd - $markerStart );
                    $i = $markerEnd;
                }
            }
        }
        return $out;
    }
 
    public function killMarkers( $text ) {
        return $this->mStripState->killMarkers( $text );
    }
 
    public static function parseWidthParam( $value, $parseHeight = true ) {
        $parsedWidthParam = [];
        if ( $value === '' ) {
            return $parsedWidthParam;
        }
        $m = [];
        # (T15500) In both cases (width/height and width only),
        # permit trailing "px" for backward compatibility.
        if ( $parseHeight && preg_match( '/^([0-9]*)x([0-9]*)\s*(?:px)?\s*$/', $value, $m ) ) {
            $width = intval( $m[1] );
            $height = intval( $m[2] );
            $parsedWidthParam['width'] = $width;
            $parsedWidthParam['height'] = $height;
        } elseif ( preg_match( '/^[0-9]*\s*(?:px)?\s*$/', $value ) ) {
            $width = intval( $value );
            $parsedWidthParam['width'] = $width;
        }
        return $parsedWidthParam;
    }
 
    protected function lock() {
        if ( $this->mInParse ) {
            throw new MWException( "Parser state cleared while parsing. "
                . "Did you call Parser::parse recursively? Lock is held by: " . $this->mInParse );
        }
 
        // Save the backtrace when locking, so that if some code tries locking again,
        // we can print the lock owner's backtrace for easier debugging
        $e = new Exception;
        $this->mInParse = $e->getTraceAsString();
 
        $recursiveCheck = new ScopedCallback( function () {
            $this->mInParse = false;
        } );
 
        return $recursiveCheck;
    }
 
    public static function stripOuterParagraph( $html ) {
        $m = [];
        if ( preg_match( '/^<p>(.*)\n?<\/p>\n?$/sU', $html, $m ) && strpos( $m[1], '</p>' ) === false ) {
            $html = $m[1];
        }
 
        return $html;
    }
 
    public function getFreshParser() {
        if ( $this->mInParse ) {
            return $this->factory->create();
        } else {
            return $this;
        }
    }
 
    public function enableOOUI() {
        wfDeprecated( __METHOD__, '1.35' );
        OutputPage::setupOOUI();
        $this->mOutput->setEnableOOUI( true );
    }
 
    private function setOutputFlag( string $flag, string $reason ): void {
        $this->mOutput->setOutputFlag( $flag );
        $name = $this->getTitle()->getPrefixedText();
        $this->logger->debug( __METHOD__ . ": set $flag flag on '$name'; $reason" );
    }
}