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[mediawiki.git] / includes / parser / ParserOutput.php

<?php
/**
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

namespace MediaWiki\Parser;

use InvalidArgumentException;
use LogicException;
use MediaWiki\Edit\ParsoidRenderID;
use MediaWiki\Json\JsonDeserializable;
use MediaWiki\Json\JsonDeserializableTrait;
use MediaWiki\Json\JsonDeserializer;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Output\OutputPage;
use MediaWiki\Parser\Parsoid\PageBundleParserOutputConverter;
use MediaWiki\Title\TitleValue;
use UnexpectedValueException;
use Wikimedia\Bcp47Code\Bcp47Code;
use Wikimedia\Bcp47Code\Bcp47CodeValue;
use Wikimedia\Message\MessageValue;
use Wikimedia\Parsoid\Core\ContentMetadataCollector;
use Wikimedia\Parsoid\Core\ContentMetadataCollectorCompat;
use Wikimedia\Parsoid\Core\LinkTarget as ParsoidLinkTarget;
use Wikimedia\Parsoid\Core\TOCData;
use Wikimedia\Reflection\GhostFieldAccessTrait;

/**
 * ParserOutput is a rendering of a Content object or a message.
 * Content objects and messages often contain wikitext, but not always.
 *
 * `ParserOutput` object combine the HTML rendering of Content objects
 * or messages, available via `::getRawText()`, with various bits of
 * metadata generated during rendering, which may include categories,
 * links, page properties, and extension data, among others.
 *
 * `ParserOutput` objects corresponding to the content of page revisions
 * are created by the `ParserOutputAccess` service, which
 * automatically caches them via `ParserCache` where appropriate and
 * produces new output via `ContentHandler` as needed.
 *
 * In addition, wikitext from system messages as well as odd bits of
 * wikitext rendered to create special pages and other UX elements are
 * rendered to `ParserOutput` objects.  In these cases the metadata
 * from the `ParserOutput` is generally discarded and the
 * `ParserOutput` is not cached.  These bits of wikitext are generally
 * rendered with `ParserOptions::setInterfaceMessage(true)` when
 * content is intended to be in the user interface language, but
 * sometimes rendered to the content language and displayed in the
 * content area instead.
 *
 * A `ParserOutput` object corresponding to a given revision may be a
 * combination of the renderings of multiple "slots":
 * the Multi-Content Revisions (MCR) work allows articles to be
 * composed from multiple `Content` objects.  Each `Content` renders
 * to a `ParserOutput`, and those `ParserOutput`s are merged by
 * `RevisionRenderer::combineSlotOutput()` to create the final article
 * output.
 *
 * Similarly, `OutputPage` maintains metadata overlapping
 * with the metadata kept by `ParserOutput` (T301020) and may merge
 * several `ParserOutput`s using `OutputPage::addParserOutput()` to
 * create the final output page.  Parsoid parses certain transclusions
 * in independent top-level contexts using
 * `Parser::parseExtensionTagAsTopLevelDoc()` and these also result in
 * `ParserOutput`s which are merged via
 * `ParserOutput::collectMetadata()`.
 *
 * Future plans for incremental parsing and asynchronous rendering may
 * result in several of these component `ParserOutput` objects being
 * cached independently and then recombined asynchronously, so
 * operations on `ParserOutput` objects should be compatible with that
 * model (T300979).
 *
 * @ingroup Parser
 */
class ParserOutput extends CacheTime implements ContentMetadataCollector {
        use GhostFieldAccessTrait;
        use JsonDeserializableTrait;
        // This is used to break cyclic dependencies and allow a measure
        // of compatibility when new methods are added to ContentMetadataCollector
        // by Parsoid.
        use ContentMetadataCollectorCompat;

        /**
         * Feature flags to indicate to extensions that MediaWiki core supports and
         * uses getText() stateless transforms.
         *
         * @since 1.31
         */
        public const SUPPORTS_STATELESS_TRANSFORMS = 1;

        /**
         * @since 1.31
         */
        public const SUPPORTS_UNWRAP_TRANSFORM = 1;

        /**
         * @internal
         * @since 1.38
         */
        public const MW_MERGE_STRATEGY_KEY = '_mw-strategy';

        /**
         * Merge strategy to use for ParserOutput accumulators: "union"
         * means that values are strings, stored as a set, and exposed as
         * a PHP associative array mapping from values to `true`.
         *
         * This constant should be treated as @internal until we expose
         * alternative merge strategies for external use.
         * @internal
         * @since 1.38
         */
        public const MW_MERGE_STRATEGY_UNION = 'union';

        /**
         * @var string|null The output text
         */
        private $mRawText = null;

        /**
         * @var array<string,string> Array mapping interwiki prefix to (non DB key) Titles (e.g. 'fr' => 'Test page')
         */
        private $mLanguageLinkMap = [];

        /**
         * @var array<string,string> Map of category names to sort keys
         */
        private $mCategories = [];

        /**
         * @var array<string,string> Page status indicators, usually displayed in top-right corner.
         */
        private $mIndicators = [];

        /**
         * @var string Title text of the chosen language variant, as HTML.
         */
        private $mTitleText;

        /**
         * @var array<int,array<string,int>> 2-D map of NS/DBK to ID for the links in the document.
         *  ID=zero for broken.
         */
        private $mLinks = [];

        /**
         * @var array<string,int> Keys are DBKs for the links to special pages in the document.
         * @since 1.35
         */
        private $mLinksSpecial = [];

        /**
         * @var array<int,array<string,int>> 2-D map of NS/DBK to ID for the template references.
         *  ID=zero for broken.
         */
        private $mTemplates = [];

        /**
         * @var array<int,array<string,int>> 2-D map of NS/DBK to rev ID for the template references.
         *  ID=zero for broken.
         */
        private $mTemplateIds = [];

        /**
         * @var array<string,int> DB keys of the images used, in the array key only
         */
        private $mImages = [];

        /**
         * @var array<string,array<string,string>> DB keys of the images used mapped to sha1 and MW timestamp.
         */
        private $mFileSearchOptions = [];

        /**
         * @var array<string,int> External link URLs, in the key only.
         */
        private array $mExternalLinks = [];

        /**
         * @var array<string,array<string,int>> 2-D map of prefix/DBK (in keys only)
         *  for the inline interwiki links in the document.
         */
        private $mInterwikiLinks = [];

        /**
         * @var bool Show a new section link?
         */
        private $mNewSection = false;

        /**
         * @var bool Hide the new section link?
         */
        private $mHideNewSection = false;

        /**
         * @var bool No gallery on category page? (__NOGALLERY__).
         */
        private $mNoGallery = false;

        /**
         * @var string[] Items to put in the <head> section
         */
        private $mHeadItems = [];

        /**
         * @var array<string,true> Modules to be loaded by ResourceLoader
         */
        private $mModuleSet = [];

        /**
         * @var array<string,true> Modules of which only the CSS will be loaded by ResourceLoader.
         */
        private $mModuleStyleSet = [];

        /**
         * @var array JavaScript config variable for mw.config combined with this page.
         */
        private $mJsConfigVars = [];

        /**
         * @var array<string,int> Warning text to be returned to the user.
         *  Wikitext formatted, in the key only.
         */
        private $mWarnings = [];

        /**
         * @var array<string,array> *Unformatted* warning messages and
         * arguments to be returned to the user.  This is for internal use
         * when merging ParserOutputs and are not serialized/deserialized.
         */
        private $mWarningMsgs = [];

        /**
         * @var ?TOCData Table of contents data, or null if it hasn't been set.
         */
        private $mTOCData;

        /**
         * @var array Name/value pairs to be cached in the DB.
         */
        private $mProperties = [];

        /**
         * @var ?string Timestamp of the revision.
         */
        private $mTimestamp;

        /**
         * @var bool Whether OOUI should be enabled.
         */
        private $mEnableOOUI = false;

        /**
         * @var bool Whether the index policy has been set to 'index'.
         */
        private $mIndexSet = false;

        /**
         * @var bool Whether the index policy has been set to 'noindex'.
         */
        private $mNoIndexSet = false;

        /**
         * @var array extra data used by extensions.
         */
        private $mExtensionData = [];

        /**
         * @var array Parser limit report data.
         */
        private $mLimitReportData = [];

        /** @var array Parser limit report data for JSON */
        private $mLimitReportJSData = [];

        /** @var string Debug message added by ParserCache */
        private $mCacheMessage = '';

        /**
         * @var array Timestamps for getTimeSinceStart().
         */
        private $mParseStartTime = [];

        /**
         * @var array Durations for getTimeProfile().
         */
        private $mTimeProfile = [];

        /**
         * @var bool Whether to emit X-Frame-Options: DENY.
         * This controls if anti-clickjacking / frame-breaking headers will
         * be sent. This should be done for pages where edit actions are possible.
         */
        private $mPreventClickjacking = false;

        /**
         * @var string[] Extra script-src for CSP
         */
        private $mExtraScriptSrcs = [];

        /**
         * @var string[] Extra default-src for CSP [Everything but script and style]
         */
        private $mExtraDefaultSrcs = [];

        /**
         * @var string[] Extra style-src for CSP
         */
        private $mExtraStyleSrcs = [];

        /**
         * @var array<string,true> Generic flags.
         */
        private $mFlags = [];

        private const SPECULATIVE_FIELDS = [
                'speculativePageIdUsed',
                'mSpeculativeRevId',
                'revisionTimestampUsed',
        ];

        /** @var int|null Assumed rev ID for {{REVISIONID}} if no revision is set */
        private $mSpeculativeRevId;
        /** @var int|null Assumed page ID for {{PAGEID}} if no revision is set */
        private $speculativePageIdUsed;
        /** @var string|null Assumed rev timestamp for {{REVISIONTIMESTAMP}} if no revision is set */
        private $revisionTimestampUsed;

        /** @var string|null SHA-1 base 36 hash of any self-transclusion */
        private $revisionUsedSha1Base36;

        /** string CSS classes to use for the wrapping div, stored in the array keys.
         * If no class is given, no wrapper is added.
         * @var array<string,true>
         */
        private $mWrapperDivClasses = [];

        /** @var int Upper bound of expiry based on parse duration */
        private $mMaxAdaptiveExpiry = INF;

        // finalizeAdaptiveCacheExpiry() uses TTL = MAX( m * PARSE_TIME + b, MIN_AR_TTL)
        // Current values imply that m=3933.333333 and b=-333.333333
        // See https://www.nngroup.com/articles/website-response-times/
        private const PARSE_FAST_SEC = 0.100; // perceived "fast" page parse
        private const PARSE_SLOW_SEC = 1.0; // perceived "slow" page parse
        private const FAST_AR_TTL = 60; // adaptive TTL for "fast" pages
        private const SLOW_AR_TTL = 3600; // adaptive TTL for "slow" pages
        private const MIN_AR_TTL = 15; // min adaptive TTL (for pool counter, and edit stashing)

        /**
         * @param string|null $text HTML. Use null to indicate that this ParserOutput contains only
         *        meta-data, and the HTML output is undetermined, as opposed to empty. Passing null
         *        here causes hasText() to return false. In 1.39 the default value changed from ''
         *        to null.
         * @param array $languageLinks
         * @param array $categoryLinks
         * @param bool $unused
         * @param string $titletext
         */
        public function __construct( $text = null, $languageLinks = [], $categoryLinks = [],
                $unused = false, $titletext = ''
        ) {
                $this->mRawText = $text;
                $this->mCategories = $categoryLinks;
                $this->mTitleText = $titletext;
                if ( $languageLinks === null ) { // T376323
                        wfDeprecated( __METHOD__ . ' with null $languageLinks', '1.43' );
                }
                foreach ( ( $languageLinks ?? [] ) as $ll ) {
                        $this->addLanguageLink( $ll );
                }
                // If the content handler does not specify an alternative (by
                // calling ::resetParseStartTime() at a later point) then use
                // the creation of the ParserOutput as the "start of parse" time.
                $this->resetParseStartTime();
        }

        /**
         * Returns true if text was passed to the constructor, or set using setText(). Returns false
         * if null was passed to the $text parameter of the constructor to indicate that this
         * ParserOutput only contains meta-data, and the HTML output is undetermined.
         *
         * @since 1.32
         *
         * @return bool Whether this ParserOutput contains rendered text. If this returns false, the
         *         ParserOutput contains meta-data only.
         */
        public function hasText(): bool {
                return ( $this->mRawText !== null );
        }

        /**
         * Get the cacheable text with <mw:editsection> markers still in it. The
         * return value is suitable for writing back via setText() but is not valid
         * for display to the user.
         *
         * @return string
         * @since 1.27
         */
        public function getRawText() {
                if ( $this->mRawText === null ) {
                        throw new LogicException( 'This ParserOutput contains no text!' );
                }

                return $this->mRawText;
        }

        /**
         * Get the output HTML
         *
         * T293512: in the future, ParserOutput::getText() will be deprecated in favor of invoking
         * the OutputTransformPipeline directly on a ParserOutput.
         * @param array $options (since 1.31) Transformations to apply to the HTML
         *      - allowClone: (bool) Whether to clone the ParserOutput before
         *     applying transformations. Default is false.
         *  - allowTOC: (bool) Show the TOC, assuming there were enough headings
         *     to generate one and `__NOTOC__` wasn't used. Default is true,
         *     but might be statefully overridden.
         *  - injectTOC: (bool) Replace the TOC_PLACEHOLDER with TOC contents;
         *     otherwise the marker will be left in the article (and the skin
         *     will be responsible for replacing or removing it).  Default is
         *     true.
         *  - enableSectionEditLinks: (bool) Include section edit links, assuming
         *     section edit link tokens are present in the HTML. Default is true,
         *     but might be statefully overridden.
         *  - userLang: (Language) Language object used for localizing UX messages,
         *    for example the heading of the table of contents. If omitted, will
         *    use the language of the main request context.
         *  - skin: (Skin) Skin object used for transforming section edit links.
         *  - unwrap: (bool) Return text without a wrapper div. Default is false,
         *    meaning a wrapper div will be added if getWrapperDivClass() returns
         *    a non-empty string.
         *  - wrapperDivClass: (string) Wrap the output in a div and apply the given
         *    CSS class to that div. This overrides the output of getWrapperDivClass().
         *    Setting this to an empty string has the same effect as 'unwrap' => true.
         *  - deduplicateStyles: (bool) When true, which is the default, `<style>`
         *    tags with the `data-mw-deduplicate` attribute set are deduplicated by
         *    value of the attribute: all but the first will be replaced by `<link
         *    rel="mw-deduplicated-inline-style" href="mw-data:..."/>` tags, where
         *    the scheme-specific-part of the href is the (percent-encoded) value
         *    of the `data-mw-deduplicate` attribute.
         *  - absoluteURLs: (bool) use absolute URLs in all links. Default: false
         *  - includeDebugInfo: (bool) render PP limit report in HTML. Default: false
         * @return string HTML
         * @return-taint escaped
         * @deprecated since 1.42, this method has side-effects on the ParserOutput
         *  (see T353257) and so should be avoided in favor of directly invoking
         *  the default output pipeline on a ParserOutput; for now, use of
         *  ::runOutputPipeline() is preferred to ensure that ParserOptions are
         *  available.
         * Do NOT hard-deprecate this method until the corresponding patch
         * (1093952) is merged to CentralNotice wmf_deploy branch!
         */
        public function getText( $options = [] ) {
                $oldText = $this->mRawText; // T353257
                $options += [ 'allowClone' => false ];
                $po = $this->runPipelineInternal( null, $options );
                $newText = $po->getContentHolderText();
                // T353257: for back-compat only mutations to metadata performed by
                // the pipeline should be preserved; mutations to $mText should be
                // discarded.
                $this->setRawText( $oldText );
                return $newText;
        }

        /**
         * @unstable This method is transitional and will be replaced by a method
         * in another class, maybe ContentRenderer.  It allows us to break our
         * porting work into two steps; in the first we bring ParserOptions to
         * to each ::getText() callsite to ensure it is made available to the
         * postprocessing pipeline.  In the second we move this functionality
         * into the Content hierarchy and out of ParserOutput, which should become
         * a pure value object.
         *
         * @param ParserOptions $popts
         * @param array $options (since 1.31) Transformations to apply to the HTML
         *       - allowClone: (bool) Whether to clone the ParserOutput before
         *     applying transformations. Default is true.
         *  - allowTOC: (bool) Show the TOC, assuming there were enough headings
         *     to generate one and `__NOTOC__` wasn't used. Default is true,
         *     but might be statefully overridden.
         *  - injectTOC: (bool) Replace the TOC_PLACEHOLDER with TOC contents;
         *     otherwise the marker will be left in the article (and the skin
         *     will be responsible for replacing or removing it).  Default is
         *     true.
         *  - enableSectionEditLinks: (bool) Include section edit links, assuming
         *     section edit link tokens are present in the HTML. Default is true,
         *     but might be statefully overridden.
         *  - userLang: (Language) Language object used for localizing UX messages,
         *    for example the heading of the table of contents. If omitted, will
         *    use the language of the main request context.
         *  - skin: (Skin) Skin object used for transforming section edit links.
         *  - unwrap: (bool) Return text without a wrapper div. Default is false,
         *    meaning a wrapper div will be added if getWrapperDivClass() returns
         *    a non-empty string.
         *  - wrapperDivClass: (string) Wrap the output in a div and apply the given
         *    CSS class to that div. This overrides the output of getWrapperDivClass().
         *    Setting this to an empty string has the same effect as 'unwrap' => true.
         *  - deduplicateStyles: (bool) When true, which is the default, `<style>`
         *    tags with the `data-mw-deduplicate` attribute set are deduplicated by
         *    value of the attribute: all but the first will be replaced by `<link
         *    rel="mw-deduplicated-inline-style" href="mw-data:..."/>` tags, where
         *    the scheme-specific-part of the href is the (percent-encoded) value
         *    of the `data-mw-deduplicate` attribute.
         *  - absoluteURLs: (bool) use absolute URLs in all links. Default: false
         *  - includeDebugInfo: (bool) render PP limit report in HTML. Default: false
         *  It is planned to eventually deprecate this $options array and to be able to
         *  pass its content in the $popts ParserOptions.
         * @return ParserOutput
         */
        public function runOutputPipeline( ParserOptions $popts, array $options = [] ): ParserOutput {
                return $this->runPipelineInternal( $popts, $options );
        }

        /**
         * Temporary helper method to allow running the pipeline with null $popts for now, although
         * passing a null ParserOptions is a temporary backward-compatibility hack and will be deprecated.
         */
        private function runPipelineInternal( ?ParserOptions $popts, array $options = [] ): ParserOutput {
                $pipeline = MediaWikiServices::getInstance()->getDefaultOutputPipeline();
                $options += [
                        'allowClone' => true,
                        'allowTOC' => true,
                        'injectTOC' => true,
                        'enableSectionEditLinks' => !$this->getOutputFlag( ParserOutputFlags::NO_SECTION_EDIT_LINKS ),
                        'userLang' => null,
                        'skin' => null,
                        'unwrap' => false,
                        'wrapperDivClass' => $this->getWrapperDivClass(),
                        'deduplicateStyles' => true,
                        'absoluteURLs' => false,
                        'includeDebugInfo' => false,
                        'isParsoidContent' => PageBundleParserOutputConverter::hasPageBundle( $this ),
                ];
                return $pipeline->run( $this, $popts, $options );
        }

        /**
         * Adds a comment notice about cache state to the text of the page
         * @param string $msg
         * @internal used by ParserCache
         */
        public function addCacheMessage( string $msg ): void {
                $this->mCacheMessage .= $msg;
        }

        /**
         * Add a CSS class to use for the wrapping div. If no class is given, no wrapper is added.
         *
         * @param string $class
         */
        public function addWrapperDivClass( $class ): void {
                $this->mWrapperDivClasses[$class] = true;
        }

        /**
         * Clears the CSS class to use for the wrapping div, effectively disabling the wrapper div
         * until addWrapperDivClass() is called.
         */
        public function clearWrapperDivClass(): void {
                $this->mWrapperDivClasses = [];
        }

        /**
         * Returns the class (or classes) to be used with the wrapper div for this output.
         * If there is no wrapper class given, no wrapper div should be added.
         * The wrapper div is added automatically by getText().
         *
         * @return string
         */
        public function getWrapperDivClass(): string {
                return implode( ' ', array_keys( $this->mWrapperDivClasses ) );
        }

        /**
         * @param int $id
         * @since 1.28
         */
        public function setSpeculativeRevIdUsed( $id ): void {
                $this->mSpeculativeRevId = $id;
        }

        /**
         * @return int|null
         * @since 1.28
         */
        public function getSpeculativeRevIdUsed(): ?int {
                return $this->mSpeculativeRevId;
        }

        /**
         * @param int $id
         * @since 1.34
         */
        public function setSpeculativePageIdUsed( $id ): void {
                $this->speculativePageIdUsed = $id;
        }

        /**
         * @return int|null
         * @since 1.34
         */
        public function getSpeculativePageIdUsed() {
                return $this->speculativePageIdUsed;
        }

        /**
         * @param string $timestamp TS_MW timestamp
         * @since 1.34
         */
        public function setRevisionTimestampUsed( $timestamp ): void {
                $this->revisionTimestampUsed = $timestamp;
        }

        /**
         * @return string|null TS_MW timestamp or null if not used
         * @since 1.34
         */
        public function getRevisionTimestampUsed() {
                return $this->revisionTimestampUsed;
        }

        /**
         * @param string $hash Lowercase SHA-1 base 36 hash
         * @since 1.34
         */
        public function setRevisionUsedSha1Base36( $hash ): void {
                if ( $hash === null ) {
                        return; // e.g. RevisionRecord::getSha1() returned null
                }

                if (
                        $this->revisionUsedSha1Base36 !== null &&
                        $this->revisionUsedSha1Base36 !== $hash
                ) {
                        $this->revisionUsedSha1Base36 = ''; // mismatched
                } else {
                        $this->revisionUsedSha1Base36 = $hash;
                }
        }

        /**
         * @return string|null Lowercase SHA-1 base 36 hash, null if unused, or "" on inconsistency
         * @since 1.34
         */
        public function getRevisionUsedSha1Base36() {
                return $this->revisionUsedSha1Base36;
        }

        /**
         * @return string[]
         * @note Before 1.43, this function returned an array reference.
         * @deprecated since 1.43, use ::getLinkList(ParserOutputLinkTypes::LANGUAGE)
         */
        public function getLanguageLinks() {
                $result = [];
                foreach ( $this->mLanguageLinkMap as $lang => $title ) {
                        // T374736: Back-compat with empty prefix; see ::addLanguageLink()
                        $result[] = $title === '|' ? "$lang" : "$lang:$title";
                }
                return $result;
        }

        /** @deprecated since 1.43, use ::getLinkList(ParserOutputLinkTypes::INTERWIKI) */
        public function getInterwikiLinks() {
                return $this->mInterwikiLinks;
        }

        /**
         * Return the names of the categories on this page.
         * Unlike ::getCategories(), sort keys are *not* included in the
         * return value.
         * @return array<string> The names of the categories
         * @since 1.38
         */
        public function getCategoryNames(): array {
                # Note that numeric category names get converted to 'int' when
                # stored as array keys; stringify the keys to ensure they
                # return to original string form so as not to confuse callers.
                return array_map( 'strval', array_keys( $this->mCategories ) );
        }

        /**
         * Return category names and sort keys as a map.
         *
         * BEWARE that numeric category names get converted to 'int' when stored
         * as array keys.  Because of this, use of this method is not recommended
         * in new code; using ::getCategoryNames() and ::getCategorySortKey() will
         * be less error-prone.
         *
         * @return array<string|int,string>
         * @internal
         */
        public function getCategoryMap(): array {
                return $this->mCategories;
        }

        /**
         * Return the sort key for a given category name, or `null` if the
         * category is not present in this ParserOutput.  Returns the
         * empty string if the category is to use the default sort key.
         *
         * @note The effective sort key in the database may vary from what
         * is returned here; see note in ParserOutput::addCategory().
         *
         * @param string $name The category name
         * @return ?string The sort key for the category, or `null` if the
         *  category is not present in this ParserOutput
         * @since 1.40
         */
        public function getCategorySortKey( string $name ): ?string {
                // This API avoids exposing the fact that numeric string category
                // names are going to be converted to 'int' when used as array
                // keys for the `mCategories` field.
                return $this->mCategories[$name] ?? null;
        }

        /**
         * @return string[]
         * @since 1.25
         */
        public function getIndicators(): array {
                return $this->mIndicators;
        }

        public function getTitleText() {
                return $this->mTitleText;
        }

        /**
         * @return ?TOCData the table of contents data, or null if it hasn't been
         * set.
         */
        public function getTOCData(): ?TOCData {
                return $this->mTOCData;
        }

        /**
         * @internal
         * @return string
         */
        public function getCacheMessage(): string {
                return $this->mCacheMessage;
        }

        /**
         * @internal
         * @return array
         */
        public function getSections(): array {
                if ( $this->mTOCData !== null ) {
                        return $this->mTOCData->toLegacy();
                }
                // For compatibility
                return [];
        }

        /**
         * Get a list of links of the given type.
         *
         * Provides a uniform interface to various lists of links stored in
         * the metadata.
         *
         * Each element of the returned array has a LinkTarget as the 'link'
         * property.  Local and template links also have 'pageid' set.
         * Template links have 'revid' set.  Category links have 'sort' set.
         * Media links optionally have 'time' and 'sha1' set.
         *
         * @param string $linkType A link type, which should be a constant from
         *  ParserOutputLinkTypes.
         * @return list<array{link:ParsoidLinkTarget,pageid?:int,revid?:int,sort?:string,time?:string|false,sha1?:string|false}>
         */
        public function getLinkList( string $linkType ): array {
                # Note that fragments are dropped for everything except language links
                $result = [];
                switch ( $linkType ) {
                        case ParserOutputLinkTypes::CATEGORY:
                                foreach ( $this->mCategories as $dbkey => $sort ) {
                                        $result[] = [
                                                'link' => new TitleValue( NS_CATEGORY, (string)$dbkey ),
                                                'sort' => $sort,
                                        ];
                                }
                                break;

                        case ParserOutputLinkTypes::INTERWIKI:
                                foreach ( $this->mInterwikiLinks as $prefix => $arr ) {
                                        foreach ( $arr as $dbkey => $ignore ) {
                                                $result[] = [
                                                        'link' => new TitleValue( NS_MAIN, (string)$dbkey, '', (string)$prefix ),
                                                ];
                                        }
                                }
                                break;

                        case ParserOutputLinkTypes::LANGUAGE:
                                foreach ( $this->mLanguageLinkMap as $lang => $title ) {
                                        if ( $title === '|' ) {
                                                continue; // T374736
                                        }
                                        # language links can have fragments!
                                        [ $title, $frag ] = array_pad( explode( '#', $title, 2 ), 2, '' );
                                        $result[]  = [
                                                'link' => new TitleValue( NS_MAIN, $title, $frag, (string)$lang ),
                                        ];
                                }
                                break;

                        case ParserOutputLinkTypes::LOCAL:
                                foreach ( $this->mLinks as $ns => $arr ) {
                                        foreach ( $arr as $dbkey => $id ) {
                                                $result[] = [
                                                        'link' => new TitleValue( $ns, (string)$dbkey ),
                                                        'pageid' => $id,
                                                ];
                                        }
                                }
                                break;

                        case ParserOutputLinkTypes::MEDIA:
                                foreach ( $this->mImages as $dbkey => $ignore ) {
                                        $extra = $this->mFileSearchOptions[$dbkey] ?? [];
                                        $extra['link'] = new TitleValue( NS_FILE, (string)$dbkey );
                                        $result[] = $extra;
                                }
                                break;

                        case ParserOutputLinkTypes::SPECIAL:
                                foreach ( $this->mLinksSpecial as $dbkey => $ignore ) {
                                        $result[] = [
                                                'link' => new TitleValue( NS_SPECIAL, (string)$dbkey ),
                                        ];
                                }
                                break;

                        case ParserOutputLinkTypes::TEMPLATE:
                                foreach ( $this->mTemplates as $ns => $arr ) {
                                        foreach ( $arr as $dbkey => $pageid ) {
                                                $result[] = [
                                                        'link' => new TitleValue( $ns, (string)$dbkey ),
                                                        'pageid' => $pageid,
                                                        // default to invalid/broken revision if this is not present
                                                        'revid' => $this->mTemplateIds[$ns][$dbkey] ?? 0,
                                                ];
                                        }
                                }
                                break;

                        default:
                                throw new UnexpectedValueException( "Unknown link type $linkType" );
                }
                return $result;
        }

        /** @deprecated since 1.43, use ::getLinkList(ParserOutputLinkTypes::LOCAL) */
        public function &getLinks() {
                return $this->mLinks;
        }

        /**
         * Return true if the given parser output has local links registered
         * in the metadata.
         * @return bool
         * @since 1.44
         */
        public function hasLinks(): bool {
                foreach ( $this->mLinks as $ns => $arr ) {
                        foreach ( $arr as $dbkey => $id ) {
                                return true;
                        }
                }
                return false;
        }

        /**
         * @return array Keys are DBKs for the links to special pages in the document
         * @since 1.35
         * @deprecated since 1.43, use ::getLinkList(ParserOutputLinkTypes::SPECIAL)
         */
        public function &getLinksSpecial() {
                return $this->mLinksSpecial;
        }

        /** @deprecated since 1.43, use ::getLinkList(ParserOutputLinkTypes::TEMPLATE) */
        public function &getTemplates() {
                return $this->mTemplates;
        }

        /** @deprecated since 1.43, use ::getLinkList(ParserOutputLinkTypes::TEMPLATE) */
        public function &getTemplateIds() {
                return $this->mTemplateIds;
        }

        /** @deprecated since 1.43, use ::getLinkList(ParserOutputLinkTypes::MEDIA) */
        public function &getImages() {
                return $this->mImages;
        }

        /**
         * Return true if there are image dependencies registered for this
         * ParserOutput.
         * @since 1.44
         */
        public function hasImages(): bool {
                return $this->mImages !== [];
        }

        /** @deprecated since 1.43, use ::getLinkList(ParserOutputLinkTypes::MEDIA) */
        public function &getFileSearchOptions() {
                return $this->mFileSearchOptions;
        }

        /**
         * @note Use of the reference returned by this method has been
         *  deprecated since 1.43.  In a future release this will return a
         *  normal array.  Use ::addExternalLink() to modify the set of
         *  external links stored in this ParserOutput.
         */
        public function &getExternalLinks(): array {
                return $this->mExternalLinks;
        }

        public function setNoGallery( $value ): void {
                $this->mNoGallery = (bool)$value;
        }

        public function getNoGallery() {
                return $this->mNoGallery;
        }

        public function getHeadItems() {
                return $this->mHeadItems;
        }

        public function getModules() {
                return array_keys( $this->mModuleSet );
        }

        public function getModuleStyles() {
                return array_keys( $this->mModuleStyleSet );
        }

        /**
         * @param bool $showStrategyKeys Defaults to false; if set to true will
         *  expose the internal `MW_MERGE_STRATEGY_KEY` in the result.  This
         *  should only be used internally to allow safe merge of config vars.
         * @return array
         * @since 1.23
         */
        public function getJsConfigVars( bool $showStrategyKeys = false ) {
                $result = $this->mJsConfigVars;
                // Don't expose the internal strategy key
                foreach ( $result as &$value ) {
                        if ( is_array( $value ) && !$showStrategyKeys ) {
                                unset( $value[self::MW_MERGE_STRATEGY_KEY] );
                        }
                }
                return $result;
        }

        public function getWarnings(): array {
                return array_keys( $this->mWarnings );
        }

        public function getIndexPolicy(): string {
                // 'noindex' wins if both are set. (T16899)
                if ( $this->mNoIndexSet ) {
                        return 'noindex';
                } elseif ( $this->mIndexSet ) {
                        return 'index';
                }
                return '';
        }

        /**
         * @return string|null TS_MW timestamp of the revision content
         */
        public function getRevisionTimestamp(): ?string {
                return $this->mTimestamp;
        }

        /**
         * @return string|null TS_MW timestamp of the revision content
         * @deprecated since 1.42; use ::getRevisionTimestamp() instead
         */
        public function getTimestamp() {
                return $this->getRevisionTimestamp();
        }

        public function getLimitReportData() {
                return $this->mLimitReportData;
        }

        public function getLimitReportJSData() {
                return $this->mLimitReportJSData;
        }

        public function getEnableOOUI() {
                return $this->mEnableOOUI;
        }

        /**
         * Get extra Content-Security-Policy 'default-src' directives
         * @since 1.35
         * @return string[]
         */
        public function getExtraCSPDefaultSrcs() {
                return $this->mExtraDefaultSrcs;
        }

        /**
         * Get extra Content-Security-Policy 'script-src' directives
         * @since 1.35
         * @return string[]
         */
        public function getExtraCSPScriptSrcs() {
                return $this->mExtraScriptSrcs;
        }

        /**
         * Get extra Content-Security-Policy 'style-src' directives
         * @since 1.35
         * @return string[]
         */
        public function getExtraCSPStyleSrcs() {
                return $this->mExtraStyleSrcs;
        }

        /**
         * Set the raw text of the ParserOutput.
         *
         * If you did not generate html, pass null to mark it as such.
         *
         * @since 1.42
         * @param string|null $text HTML content of ParserOutput or null if not generated
         * @param-taint $text exec_html
         */
        public function setRawText( ?string $text ): void {
                $this->mRawText = $text;
        }

        /**
         * Set the raw text of the ParserOutput.
         *
         * If you did not generate html, pass null to mark it as such.
         *
         * @since 1.39 You can now pass null to this function
         * @param string|null $text HTML content of ParserOutput or null if not generated
         * @param-taint $text exec_html
         * @return string|null Previous value of ParserOutput's raw text
         * @deprecated since 1.42; use ::setRawText() which matches the getter ::getRawText()
         */
        public function setText( $text ) {
                return wfSetVar( $this->mRawText, $text, true );
        }

        /**
         * @deprecated since 1.42, use ::addLanguageLink() instead.
         */
        public function setLanguageLinks( $ll ) {
                $old = $this->getLanguageLinks();
                $this->mLanguageLinkMap = [];
                if ( $ll === null ) { // T376323
                        wfDeprecated( __METHOD__ . ' with null argument', '1.43' );
                }
                foreach ( ( $ll ?? [] ) as $l ) {
                        $this->addLanguageLink( $l );
                }
                return $old;
        }

        public function setTitleText( $t ) {
                return wfSetVar( $this->mTitleText, $t );
        }

        /**
         * @param TOCData $tocData Table of contents data for the page
         */
        public function setTOCData( TOCData $tocData ): void {
                $this->mTOCData = $tocData;
        }

        /**
         * @param array $sectionArray
         * @return array Previous value of ::getSections()
         */
        public function setSections( array $sectionArray ) {
                $oldValue = $this->getSections();
                $this->setTOCData( TOCData::fromLegacy( $sectionArray ) );
                return $oldValue;
        }

        /**
         * Update the index policy of the robots meta tag.
         *
         * Note that calling this method does not guarantee
         * that {@link self::getIndexPolicy()} will return the given policy –
         * if different calls set the index policy to 'index' and 'noindex',
         * then 'noindex' always wins (T16899), even if the 'index' call happened later.
         * If this is not what you want,
         * you can reset {@link ParserOutputFlags::NO_INDEX_POLICY} with {@link self::setOutputFlag()}.
         *
         * @param string $policy 'index' or 'noindex'.
         * @return string The previous policy.
         */
        public function setIndexPolicy( $policy ): string {
                $old = $this->getIndexPolicy();
                if ( $policy === 'noindex' ) {
                        $this->mNoIndexSet = true;
                } elseif ( $policy === 'index' ) {
                        $this->mIndexSet = true;
                }
                return $old;
        }

        /**
         * @param ?string $timestamp TS_MW timestamp of the revision content
         */
        public function setRevisionTimestamp( ?string $timestamp ): void {
                $this->mTimestamp = $timestamp;
        }

        /**
         * @param ?string $timestamp TS_MW timestamp of the revision content
         *
         * @return ?string The previous value of the timestamp
         * @deprecated since 1.42; use ::setRevisionTimestamp() instead
         */
        public function setTimestamp( $timestamp ) {
                return wfSetVar( $this->mTimestamp, $timestamp );
        }

        /**
         * Add a category.
         *
         * Although ParserOutput::getCategorySortKey() will return exactly
         * the sort key you specify here, before storing in the database
         * all sort keys will be language converted, HTML entities will be
         * decoded, newlines stripped, and then they will be truncated to
         * 255 bytes. Thus the "effective" sort key in the DB may be different
         * from what is passed to `$sort` here and returned by
         * ::getCategorySortKey().
         *
         * @param string|ParsoidLinkTarget $c The category name
         * @param string $sort The sort key; an empty string indicates
         *  that the default sort key for the page should be used.
         */
        public function addCategory( $c, $sort = '' ): void {
                if ( $c instanceof ParsoidLinkTarget ) {
                        $c = $c->getDBkey();
                }
                $this->mCategories[$c] = $sort;
        }

        /**
         * Overwrite the category map.
         * @param array<string,string> $c Map of category names to sort keys
         * @since 1.38
         */
        public function setCategories( array $c ): void {
                $this->mCategories = $c;
        }

        /**
         * @param string $id
         * @param string $content
         * @param-taint $content exec_html
         * @since 1.25
         */
        public function setIndicator( $id, $content ): void {
                $this->mIndicators[$id] = $content;
        }

        /**
         * Enables OOUI, if true, in any OutputPage instance this ParserOutput
         * object is added to.
         *
         * @since 1.26
         * @param bool $enable If OOUI should be enabled or not
         */
        public function setEnableOOUI( bool $enable = false ): void {
                $this->mEnableOOUI = $enable;
        }

        /**
         * Add a language link.
         * @param ParsoidLinkTarget|string $t
         */
        public function addLanguageLink( $t ): void {
                # Note that fragments are preserved
                if ( $t instanceof ParsoidLinkTarget ) {
                        // Language links are unusual in using 'text' rather than 'db key'
                        // Note that fragments are preserved.
                        $lang = $t->getInterwiki();
                        $title = $t->getText();
                        if ( $t->hasFragment() ) {
                                $title .= '#' . $t->getFragment();
                        }
                } else {
                        [ $lang, $title ] = array_pad( explode( ':', $t, 2 ), -2, '' );
                }
                if ( $lang === '' ) {
                        // T374736: For backward compatibility with test cases only!
                        wfDeprecated( __METHOD__ . ' without prefix', '1.43' );
                        [ $lang, $title ] = [ $title, '|' ]; // | can not occur in valid title
                }
                $this->mLanguageLinkMap[$lang] ??= $title;
        }

        /**
         * Add a warning to the output for this page.
         * @param MessageValue $mv
         * @since 1.43
         */
        public function addWarningMsgVal( MessageValue $mv ) {
                // These can eventually be stored as MessageValue directly.
                $this->addWarningMsg( $mv->getKey(), ...$mv->getParams() );
        }

        /**
         * Add a warning to the output for this page.
         * @param string $msg The localization message key for the warning
         * @param mixed|JsonDeserializable ...$args Optional arguments for the
         *   message. These arguments must be serializable/deserializable with
         *   JsonCodec; see the @note on ParserOutput::setExtensionData()
         * @since 1.38
         */
        public function addWarningMsg( string $msg, ...$args ): void {
                // MessageValue objects are defined in core and thus not visible
                // to Parsoid or to its ContentMetadataCollector interface.
                // Eventually this method (defined in ContentMetadataCollector) should
                // call ::addWarningMsgVal() instead of the other way around.

                // preserve original arguments in $mWarningMsgs to allow merge
                // @todo: these aren't serialized/deserialized yet -- before we
                // turn on serialization of $this->mWarningMsgs we need to ensure
                // callers aren't passing nonserializable arguments: T343048.
                $jsonCodec = MediaWikiServices::getInstance()->getJsonCodec();
                $path = $jsonCodec->detectNonSerializableData( $args, true );
                if ( $path !== null ) {
                        wfDeprecatedMsg(
                                "ParserOutput::addWarningMsg() called with nonserializable arguments: $path",
                                '1.41'
                        );
                }
                $this->mWarningMsgs[$msg] = $args;
                $s = wfMessage( $msg, ...$args )
                        // some callers set the title here?
                        ->inContentLanguage() // because this ends up in cache
                        ->text();
                $this->mWarnings[$s] = 1;
        }

        public function setNewSection( $value ): void {
                $this->mNewSection = (bool)$value;
        }

        /**
         * @param bool $value Hide the new section link?
         */
        public function setHideNewSection( bool $value ): void {
                $this->mHideNewSection = $value;
        }

        public function getHideNewSection(): bool {
                return (bool)$this->mHideNewSection;
        }

        public function getNewSection(): bool {
                return (bool)$this->mNewSection;
        }

        /**
         * Checks, if a url is pointing to the own server
         *
         * @param string $internal The server to check against
         * @param string $url The url to check
         * @return bool
         * @internal
         */
        public static function isLinkInternal( $internal, $url ): bool {
                return (bool)preg_match( '/^' .
                        # If server is proto relative, check also for http/https links
                        ( substr( $internal, 0, 2 ) === '//' ? '(?:https?:)?' : '' ) .
                        preg_quote( $internal, '/' ) .
                        # check for query/path/anchor or end of link in each case
                        '(?:[\?\/\#]|$)/i',
                        $url
                );
        }

        public function addExternalLink( $url ): void {
                # We don't register links pointing to our own server, unless... :-)
                $config = MediaWikiServices::getInstance()->getMainConfig();
                $server = $config->get( MainConfigNames::Server );
                $registerInternalExternals = $config->get( MainConfigNames::RegisterInternalExternals );
                # Replace unnecessary URL escape codes with the referenced character
                # This prevents spammers from hiding links from the filters
                $url = Parser::normalizeLinkUrl( $url );

                $registerExternalLink = true;
                if ( !$registerInternalExternals ) {
                        $registerExternalLink = !self::isLinkInternal( $server, $url );
                }
                if ( $registerExternalLink ) {
                        $this->mExternalLinks[$url] = 1;
                }
        }

        /**
         * Record a local or interwiki inline link for saving in future link tables.
         *
         * @param ParsoidLinkTarget $link (used to require Title until 1.38)
         * @param int|null $id Optional known page_id so we can skip the lookup
         */
        public function addLink( ParsoidLinkTarget $link, $id = null ): void {
                if ( $link->isExternal() ) {
                        // Don't record interwikis in pagelinks
                        $this->addInterwikiLink( $link );
                        return;
                }
                $ns = $link->getNamespace();
                $dbk = $link->getDBkey();
                if ( $ns === NS_MEDIA ) {
                        // Normalize this pseudo-alias if it makes it down here...
                        $ns = NS_FILE;
                } elseif ( $ns === NS_SPECIAL ) {
                        // We don't want to record Special: links in the database, so put them in a separate place.
                        // It might actually be wise to, but we'd need to do some normalization.
                        $this->mLinksSpecial[$dbk] = 1;
                        return;
                } elseif ( $dbk === '' ) {
                        // Don't record self links -  [[#Foo]]
                        return;
                }
                if ( $id === null ) {
                        // T357048: This actually kills performance; we should batch these.
                        $page = MediaWikiServices::getInstance()->getPageStore()->getPageForLink( $link );
                        $id = $page->getId();
                }
                $this->mLinks[$ns][$dbk] = $id;
        }

        /**
         * Register a file dependency for this output
         * @param string|ParsoidLinkTarget $name Title dbKey
         * @param string|false|null $timestamp MW timestamp of file creation (or false if non-existing)
         * @param string|false|null $sha1 Base 36 SHA-1 of file (or false if non-existing)
         */
        public function addImage( $name, $timestamp = null, $sha1 = null ): void {
                if ( $name instanceof ParsoidLinkTarget ) {
                        $name = $name->getDBkey();
                }
                $this->mImages[$name] = 1;
                if ( $timestamp !== null && $sha1 !== null ) {
                        $this->mFileSearchOptions[$name] = [ 'time' => $timestamp, 'sha1' => $sha1 ];
                }
        }

        /**
         * Register a template dependency for this output
         *
         * @param ParsoidLinkTarget $link (used to require Title until 1.38)
         * @param int $page_id
         * @param int $rev_id
         */
        public function addTemplate( $link, $page_id, $rev_id ): void {
                if ( $link->isExternal() ) {
                        // Will throw an InvalidArgumentException in a future release.
                        wfDeprecated( __METHOD__ . " with interwiki link", '1.42' );
                        return;
                }
                $ns = $link->getNamespace();
                $dbk = $link->getDBkey();
                // T357048: Parsoid doesn't have page_id
                $this->mTemplates[$ns][$dbk] = $page_id;
                $this->mTemplateIds[$ns][$dbk] = $rev_id; // For versioning
        }

        /**
         * @param ParsoidLinkTarget $link must be an interwiki link
         *       (used to require Title until 1.38).
         */
        public function addInterwikiLink( $link ): void {
                if ( !$link->isExternal() ) {
                        throw new InvalidArgumentException( 'Non-interwiki link passed, internal parser error.' );
                }
                $prefix = $link->getInterwiki();
                $this->mInterwikiLinks[$prefix][$link->getDBkey()] = 1;
        }

        /**
         * Add some text to the "<head>".
         * If $tag is set, the section with that tag will only be included once
         * in a given page.
         * @param string $section
         * @param string|false $tag
         */
        public function addHeadItem( $section, $tag = false ): void {
                if ( $tag !== false ) {
                        $this->mHeadItems[$tag] = $section;
                } else {
                        $this->mHeadItems[] = $section;
                }
        }

        /**
         * @see OutputPage::addModules
         * @param string[] $modules
         */
        public function addModules( array $modules ): void {
                $modules = array_fill_keys( $modules, true );
                $this->mModuleSet = array_merge( $this->mModuleSet, $modules );
        }

        /**
         * @see OutputPage::addModuleStyles
         * @param string[] $modules
         */
        public function addModuleStyles( array $modules ): void {
                $modules = array_fill_keys( $modules, true );
                $this->mModuleStyleSet = array_merge( $this->mModuleStyleSet, $modules );
        }

        /**
         * Add one or more variables to be set in mw.config in JavaScript.
         *
         * @param string|array $keys Key or array of key/value pairs.
         * @param mixed|null $value [optional] Value of the configuration variable.
         * @since 1.23
         * @deprecated since 1.38, use ::setJsConfigVar() or ::appendJsConfigVar()
         *  which ensures compatibility with asynchronous parsing; emitting warnings
         *  since 1.43.
         */
        public function addJsConfigVars( $keys, $value = null ): void {
                wfDeprecated( __METHOD__, '1.38' );
                if ( is_array( $keys ) ) {
                        foreach ( $keys as $key => $value ) {
                                $this->mJsConfigVars[$key] = $value;
                        }
                        return;
                }

                $this->mJsConfigVars[$keys] = $value;
        }

        /**
         * Add a variable to be set in mw.config in JavaScript.
         *
         * In order to ensure the result is independent of the parse order, the values
         * set here must be unique -- that is, you can pass the same $key
         * multiple times but ONLY if the $value is identical each time.
         * If you want to collect multiple pieces of data under a single key,
         * use ::appendJsConfigVar().
         *
         * @param string $key Key to use under mw.config
         * @param mixed|null $value Value of the configuration variable.
         * @since 1.38
         */
        public function setJsConfigVar( string $key, $value ): void {
                if (
                        array_key_exists( $key, $this->mJsConfigVars ) &&
                        $this->mJsConfigVars[$key] !== $value
                ) {
                        // Ensure that a key is mapped to only a single value in order
                        // to prevent the resulting array from varying if content
                        // is parsed in a different order.
                        throw new InvalidArgumentException( "Multiple conflicting values given for $key" );
                }
                $this->mJsConfigVars[$key] = $value;
        }

        /**
         * Append a value to a variable to be set in mw.config in JavaScript.
         *
         * In order to ensure the result is independent of the parse order,
         * the value of this key will be an associative array, mapping all of
         * the values set under that key to true.  (The array is implicitly
         * ordered in PHP, but you should treat it as unordered.)
         * If you want a non-array type for the key, and can ensure that only
         * a single value will be set, you should use ::setJsConfigVar() instead.
         *
         * @param string $key Key to use under mw.config
         * @param string $value Value to append to the configuration variable.
         * @param string $strategy Merge strategy:
         *  only MW_MERGE_STRATEGY_UNION is currently supported and external callers
         *  should treat this parameter as @internal at this time and omit it.
         * @since 1.38
         */
        public function appendJsConfigVar(
                string $key,
                string $value,
                string $strategy = self::MW_MERGE_STRATEGY_UNION
        ): void {
                if ( $strategy !== self::MW_MERGE_STRATEGY_UNION ) {
                        throw new InvalidArgumentException( "Unknown merge strategy $strategy." );
                }
                if ( !array_key_exists( $key, $this->mJsConfigVars ) ) {
                        $this->mJsConfigVars[$key] = [
                                // Indicate how these values are to be merged.
                                self::MW_MERGE_STRATEGY_KEY => $strategy,
                        ];
                } elseif ( !is_array( $this->mJsConfigVars[$key] ) ) {
                        throw new InvalidArgumentException( "Mixing set and append for $key" );
                } elseif ( ( $this->mJsConfigVars[$key][self::MW_MERGE_STRATEGY_KEY] ?? null ) !== $strategy ) {
                        throw new InvalidArgumentException( "Conflicting merge strategies for $key" );
                }
                $this->mJsConfigVars[$key][$value] = true;
        }

        /**
         * Accommodate very basic transcluding of a temporary OutputPage object into parser output.
         *
         * This is a fragile method that cannot be relied upon in any meaningful way.
         * It exists solely to support the wikitext feature of transcluding a SpecialPage, and
         * only has to work for that use case to ensure relevant styles are loaded, and that
         * essential config vars needed between SpecialPage and a JS feature are added.
         *
         * This relies on there being no overlap between modules or config vars added by
         * the SpecialPage and those added by parser extensions. If there is overlap,
         * then arise and break one or both sides. This is expected and unsupported.
         *
         * @internal For use by Parser for basic special page transclusion
         * @param OutputPage $out
         */
        public function addOutputPageMetadata( OutputPage $out ): void {
                // This should eventually use the same merge mechanism used
                // internally to merge ParserOutputs together.
                // (ie: $this->mergeHtmlMetaDataFrom( $out->getMetadata() )
                // once preventClickjacking, moduleStyles, modules, jsconfigvars,
                // and head items are moved to OutputPage::$metadata)

                // Take the strictest click-jacking policy. This is to ensure any one-click features
                // such as patrol or rollback on the transcluded special page will result in the wiki page
                // disallowing embedding in cross-origin iframes. Articles are generally allowed to be
                // embedded. Pages that transclude special pages are expected to be user pages or
                // other non-content pages that content re-users won't discover or care about.
                $this->mPreventClickjacking = $this->mPreventClickjacking || $out->getPreventClickjacking();

                $this->addModuleStyles( $out->getModuleStyles() );

                // TODO: Figure out if style modules suffice, or whether the below is needed as well.
                // Are there special pages that permit transcluding/including and also have JS modules
                // that should be activate on the host page?
                $this->addModules( $out->getModules() );
                $this->mJsConfigVars = self::mergeMapStrategy(
                        $this->mJsConfigVars, $out->getJsConfigVars()
                );
                $this->mHeadItems = array_merge( $this->mHeadItems, $out->getHeadItemsArray() );
        }

        /**
         * Override the title to be used for display
         *
         * @note this is assumed to have been validated
         * (check equal normalisation, etc.)
         *
         * @note this is expected to be safe HTML,
         * ready to be served to the client.
         *
         * @param string $text Desired title text
         */
        public function setDisplayTitle( $text ): void {
                $this->setTitleText( $text );
                $this->setPageProperty( 'displaytitle', $text );
        }

        /**
         * Get the title to be used for display.
         *
         * As per the contract of setDisplayTitle(), this is safe HTML,
         * ready to be served to the client.
         *
         * @return string|false HTML
         */
        public function getDisplayTitle() {
                $t = $this->getTitleText();
                if ( $t === '' ) {
                        return false;
                }
                return $t;
        }

        /**
         * Get the primary language code of the output.
         *
         * This returns the primary language of the output, including
         * any LanguageConverter variant applied.
         *
         * NOTE: This may differ from the wiki's default content language
         * ($wgLanguageCode, MediaWikiServices::getContentLanguage), because
         * each page may have its own "page language" set (PageStoreRecord,
         * Title::getDbPageLanguageCode, ContentHandler::getPageLanguage).
         *
         * NOTE: This may differ from the "page language" when parsing
         * user interface messages, in which case this reflects the user
         * language (including any variant preference).
         *
         * NOTE: This may differ from the Parser's "target language" that was
         * set while the Parser was parsing the page, because the final output
         * is converted to the current user's preferred LanguageConverter variant
         * (assuming this is a variant of the target language).
         * See Parser::getTargetLanguageConverter()->getPreferredVariant(); use
         * LanguageFactory::getParentLanguage() on the language code to obtain
         * the base language code. LanguageConverter::getPreferredVariant()
         * depends on the global RequestContext for the URL and the User
         * language preference.
         *
         * Finally, note that a single ParserOutput object may contain
         * HTML content in multiple different languages and directions
         * (T114640). Authors of wikitext and of parser extensions are
         * expected to mark such subtrees with a `lang` attribute (set to
         * a BCP-47 value, see Language::toBcp47Code()) and a corresponding
         * `dir` attribute (see Language::getDir()). This method returns
         * the language code for wrapper of the HTML content.
         *
         * @see Parser::internalParseHalfParsed
         * @since 1.40
         * @return ?Bcp47Code The primary language for this output,
         *   or `null` if a language was not set.
         */
        public function getLanguage(): ?Bcp47Code {
                // This information is temporarily stored in extension data (T303329)
                $code = $this->getExtensionData( 'core:target-lang-variant' );
                // This is null if the ParserOutput was cached by MW 1.40 or earlier,
                // or not constructed by Parser/ParserCache.
                return $code === null ? null : new Bcp47CodeValue( $code );
        }

        /**
         * Set the primary language of the output.
         *
         * See the discussion and caveats in ::getLanguage().
         *
         * @param Bcp47Code $lang The primary language for this output, including
         *   any variant specification.
         * @since 1.40
         */
        public function setLanguage( Bcp47Code $lang ): void {
                $this->setExtensionData( 'core:target-lang-variant', $lang->toBcp47Code() );
        }

        /**
         * Return an HTML prefix to be applied on redirect pages, or null
         * if this is not a redirect.
         * @return ?string HTML to prepend to redirect pages, or null
         * @internal
         */
        public function getRedirectHeader(): ?string {
                return $this->getExtensionData( 'core:redirect-header' );
        }

        /**
         * Set an HTML prefix to be applied on redirect pages.
         * @param string $html HTML to prepend to redirect pages
         */
        public function setRedirectHeader( string $html ): void {
                $this->setExtensionData( 'core:redirect-header', $html );
        }

        /**
         * Store a unique rendering id for this ParserOutput.  This is used
         * whenever a client needs to record a dependency on a specific parse.
         * It is typically set only when a parser output is cached.
         *
         * @param string $renderId a UUID identifying a specific parse
         * @internal
         */
        public function setRenderId( string $renderId ): void {
                $this->setExtensionData( 'core:render-id', $renderId );
        }

        /**
         * Return the unique rendering id for this ParserOutput. This is used
         * whenever a client needs to record a dependency on a specific parse.
         *
         * @return string|null
         * @internal
         */
        public function getRenderId(): ?string {
                // Backward-compatibility with old cache contents
                // Can be removed after parser cache contents have expired
                $old = $this->getExtensionData( 'parsoid-render-id' );
                if ( $old !== null ) {
                        return ParsoidRenderId::newFromKey( $old )->getUniqueID();
                }
                return $this->getExtensionData( 'core:render-id' );
        }

        /**
         * @return string[] List of flags signifying special cases
         * @internal
         */
        public function getAllFlags(): array {
                return array_keys( $this->mFlags );
        }

        /**
         * Set a page property to be stored in the page_props database table.
         *
         * page_props is a key-value store indexed by the page ID. This allows
         * the parser to set a property on a page which can then be quickly
         * retrieved given the page ID or via a DB join when given the page
         * title.
         *
         * Since 1.23, page_props are also indexed by numeric value, to allow
         * for efficient "top k" queries of pages wrt a given property.
         * This only works if the value is passed as a int, float, or
         * bool. Since 1.42 you should use ::setNumericPageProperty()
         * if you want your page property value to be indexed, which will ensure
         * that the value is of the proper type.
         *
         * setPageProperty() is thus used to propagate properties from the parsed
         * page to request contexts other than a page view of the currently parsed
         * article.
         *
         * Some applications examples:
         *
         *   * To implement hidden categories, hiding pages from category listings
         *     by storing a page property.
         *
         *   * Overriding the displayed article title (ParserOutput::setDisplayTitle()).
         *
         *   * To implement image tagging, for example displaying an icon on an
         *     image thumbnail to indicate that it is listed for deletion on
         *     Wikimedia Commons.
         *     This is not actually implemented, yet but would be pretty cool.
         *
         * @note Use of non-scalar values (anything other than
         *  `string|int|float|bool`) has been deprecated in 1.42.
         *  Although any JSON-serializable value can be stored/fetched in
         *  ParserOutput, when the values are stored to the database
         *  (in `deferred/LinksUpdate/PagePropsTable.php`) they will be
         *  converted: booleans will be converted to '0' and '1', null
         *  will become '', and everything else will be cast to string
         *  (not JSON-serialized).  Page properties obtained from the
         *  PageProps service will thus always be strings.
         *
         * @note The sort key stored in the database *will be NULL* unless
         *  the value passed here is an `int|float|bool`.  If you *do not*
         *  want your property *value* indexed and sorted (for example, the
         *  value is a title string which can be numeric but only
         *  incidentally, like when it gets retrieved from an array key)
         *  be sure to cast to string or use
         *  `::setUnsortedPageProperty()`.  If you *do* want your property
         *  *value* indexed and sorted, you should use
         *  `::setNumericPageProperty()` instead as this will ensure the
         *  value type is correct. Note that either way it is possible to
         *  efficiently look up all the pages with a certain property; we
         *  are only talking about sorting the *values* assigned to the
         *  property, for example for a "top N values of the property"
         *  query.
         *
         * @note Note that `::getPageProperty()`/`::setPageProperty()` do
         *  not do any conversions themselves; you should therefore be
         *  careful to distinguish values returned from the PageProp
         *  service (always strings) from values retrieved from a
         *  ParserOutput.
         *
         * @note Do not use setPageProperty() to set a property which is only used
         * in a context where the ParserOutput object itself is already available,
         * for example a normal page view. There is no need to save such a property
         * in the database since the text is already parsed; use
         * ::setExtensionData() instead.
         *
         * @par Example:
         * @code
         *    $parser->getOutput()->setExtensionData( 'my_ext_foo', '...' );
         * @endcode
         *
         * And then later, in OutputPageParserOutput or similar:
         *
         * @par Example:
         * @code
         *    $output->getExtensionData( 'my_ext_foo' );
         * @endcode
         *
         * @note The use of `null` as a value is deprecated since 1.42; use
         * the empty string instead if you need a placeholder value, or
         * ::unsetPageProperty() if you mean to remove a page property.
         *
         * @note The use of non-string values is deprecated since 1.42; if you
         * need an page property value with a sort index
         * use ::setNumericPageProperty().
         *
         * @param string $name
         * @param ?scalar $value
         * @since 1.38
         */
        public function setPageProperty( string $name, $value ): void {
                if ( $value === null ) {
                        // Use an empty string instead.
                        wfDeprecated( __METHOD__ . " with null value for $name", '1.42' );
                } elseif ( !is_scalar( $value ) ) {
                        // Use ::setExtensionData() instead.
                        wfDeprecated( __METHOD__ . " with non-scalar value for $name", '1.42' );
                } elseif ( !is_string( $value ) ) {
                        // Use ::setNumericPageProperty() instead.
                        wfDeprecated( __METHOD__ . " with non-string value for $name", '1.42' );
                }
                $this->mProperties[$name] = $value;
        }

        /**
         * Set a numeric page property whose *value* is intended to be sorted
         * and indexed.  The sort key used for the property will be the value,
         * coerced to a number.
         *
         * See `::setPageProperty()` for details.
         *
         * In the future, we may allow the value to be specified independent
         * of sort key (T357783).
         *
         * @param string $propName The name of the page property
         * @param int|float|string $numericValue the numeric value
         * @since 1.42
         */
        public function setNumericPageProperty( string $propName, $numericValue ): void {
                if ( !is_numeric( $numericValue ) ) {
                        throw new \TypeError( __METHOD__ . " with non-numeric value" );
                }
                // Coerce numeric sort key to a number.
                $this->mProperties[$propName] = 0 + $numericValue;
        }

        /**
         * Set a page property whose *value* is not intended to be sorted and
         * indexed.
         *
         * See `::setPageProperty()` for details.  It is recommended to
         * use the empty string if you need a placeholder value (ie, if
         * it is the *presence* of the property which is important, not
         * the *value* the property is set to).
         *
         * It is still possible to efficiently look up all the pages with
         * a certain property (the "presence" of it *is* indexed; see
         * Special:PagesWithProp, list=pageswithprop).
         *
         * @param string $propName The name of the page property
         * @param string $value Optional value; defaults to the empty string.
         * @since 1.42
         */
        public function setUnsortedPageProperty( string $propName, string $value = '' ): void {
                $this->mProperties[$propName] = $value;
        }

        /**
         * Look up a page property.
         * @param string $name The page property name to look up.
         * @return ?scalar The value previously set using
         * ::setPageProperty(), ::setUnsortedPageProperty(), or
         * ::setNumericPageProperty().
         * Returns null if no value was set for the given property name.
         *
         * @note You would need to use ::getPageProperties() to test for an
         *  explicitly-set null value; but see the note in ::setPageProperty()
         *  deprecating the use of null values.
         * @since 1.38
         */
        public function getPageProperty( string $name ) {
                return $this->mProperties[$name] ?? null;
        }

        /**
         * Remove a page property.
         * @param string $name The page property name.
         * @since 1.38
         */
        public function unsetPageProperty( string $name ): void {
                unset( $this->mProperties[$name] );
        }

        /**
         * Return all the page properties set on this ParserOutput.
         * @return array<string,?scalar>
         * @since 1.38
         */
        public function getPageProperties(): array {
                if ( !isset( $this->mProperties ) ) {
                        $this->mProperties = [];
                }
                return $this->mProperties;
        }

        /**
         * Provides a uniform interface to various boolean flags stored
         * in the ParserOutput.  Flags internal to MediaWiki core should
         * have names which are constants in ParserOutputFlags.  Extensions
         * should use ::setExtensionData() rather than creating new flags
         * with ::setOutputFlag() in order to prevent namespace conflicts.
         *
         * Flags are always combined with OR.  That is, the flag is set in
         * the resulting ParserOutput if the flag is set in *any* of the
         * fragments composing the ParserOutput.
         *
         * @note The combination policy means that a ParserOutput may end
         * up with both INDEX_POLICY and NO_INDEX_POLICY set.  It is
         * expected that NO_INDEX_POLICY "wins" in that case. (T16899)
         * (This resolution is implemented in ::getIndexPolicy().)
         *
         * @param string $name A flag name
         * @param bool $val
         * @since 1.38
         */
        public function setOutputFlag( string $name, bool $val = true ): void {
                switch ( $name ) {
                        case ParserOutputFlags::NO_GALLERY:
                                $this->setNoGallery( $val );
                                break;

                        case ParserOutputFlags::ENABLE_OOUI:
                                $this->setEnableOOUI( $val );
                                break;

                        case ParserOutputFlags::NO_INDEX_POLICY:
                                $this->mNoIndexSet = $val;
                                break;

                        case ParserOutputFlags::INDEX_POLICY:
                                $this->mIndexSet = $val;
                                break;

                        case ParserOutputFlags::NEW_SECTION:
                                $this->setNewSection( $val );
                                break;

                        case ParserOutputFlags::HIDE_NEW_SECTION:
                                $this->setHideNewSection( $val );
                                break;

                        case ParserOutputFlags::PREVENT_CLICKJACKING:
                                $this->setPreventClickjacking( $val );
                                break;

                        default:
                                if ( $val ) {
                                        $this->mFlags[$name] = true;
                                } else {
                                        unset( $this->mFlags[$name] );
                                }
                                break;
                }
        }

        /**
         * Provides a uniform interface to various boolean flags stored
         * in the ParserOutput.  Flags internal to MediaWiki core should
         * have names which are constants in ParserOutputFlags.  Extensions
         * should only use ::getOutputFlag() to query flags defined in
         * ParserOutputFlags in core; they should use ::getExtensionData()
         * to define their own flags.
         *
         * @param string $name A flag name
         * @return bool The flag value
         * @since 1.38
         */
        public function getOutputFlag( string $name ): bool {
                switch ( $name ) {
                        case ParserOutputFlags::NO_GALLERY:
                                return $this->getNoGallery();

                        case ParserOutputFlags::ENABLE_OOUI:
                                return $this->getEnableOOUI();

                        case ParserOutputFlags::INDEX_POLICY:
                                return $this->mIndexSet;

                        case ParserOutputFlags::NO_INDEX_POLICY:
                                return $this->mNoIndexSet;

                        case ParserOutputFlags::NEW_SECTION:
                                return $this->getNewSection();

                        case ParserOutputFlags::HIDE_NEW_SECTION:
                                return $this->getHideNewSection();

                        case ParserOutputFlags::PREVENT_CLICKJACKING:
                                return $this->getPreventClickjacking();

                        default:
                                return isset( $this->mFlags[$name] );

                }
        }

        /**
         * Provides a uniform interface to various string sets stored
         * in the ParserOutput.  String sets internal to MediaWiki core should
         * have names which are constants in ParserOutputStringSets.  Extensions
         * should use ::appendExtensionData() rather than creating new string sets
         * with ::appendOutputStrings() in order to prevent namespace conflicts.
         *
         * @param string $name A string set name
         * @param string[] $value
         * @since 1.41
         */
        public function appendOutputStrings( string $name, array $value ): void {
                switch ( $name ) {
                        case ParserOutputStringSets::MODULE:
                                $this->addModules( $value );
                                break;
                        case ParserOutputStringSets::MODULE_STYLE:
                                $this->addModuleStyles( $value );
                                break;
                        case ParserOutputStringSets::EXTRA_CSP_DEFAULT_SRC:
                                foreach ( $value as $v ) {
                                        $this->addExtraCSPDefaultSrc( $v );
                                }
                                break;
                        case ParserOutputStringSets::EXTRA_CSP_SCRIPT_SRC:
                                foreach ( $value as $v ) {
                                        $this->addExtraCSPScriptSrc( $v );
                                }
                                break;
                        case ParserOutputStringSets::EXTRA_CSP_STYLE_SRC:
                                foreach ( $value as $v ) {
                                        $this->addExtraCSPStyleSrc( $v );
                                }
                                break;
                        default:
                                throw new UnexpectedValueException( "Unknown output string set name $name" );
                }
        }

        /**
         * Provides a uniform interface to various boolean string sets stored
         * in the ParserOutput.  String sets internal to MediaWiki core should
         * have names which are constants in ParserOutputStringSets.  Extensions
         * should only use ::getOutputStrings() to query string sets defined in
         * ParserOutputStringSets in core; they should use ::appendExtensionData()
         * to define their own string sets.
         *
         * @param string $name A string set name
         * @return string[] The string set value
         * @since 1.41
         */
        public function getOutputStrings( string $name ): array {
                switch ( $name ) {
                        case ParserOutputStringSets::MODULE:
                                return $this->getModules();
                        case ParserOutputStringSets::MODULE_STYLE:
                                return $this->getModuleStyles();
                        case ParserOutputStringSets::EXTRA_CSP_DEFAULT_SRC:
                                return $this->getExtraCSPDefaultSrcs();
                        case ParserOutputStringSets::EXTRA_CSP_SCRIPT_SRC:
                                return $this->getExtraCSPScriptSrcs();
                        case ParserOutputStringSets::EXTRA_CSP_STYLE_SRC:
                                return $this->getExtraCSPStyleSrcs();
                        default:
                                throw new UnexpectedValueException( "Unknown output string set name $name" );
                }
        }

        /**
         * Attaches arbitrary data to this ParserObject. This can be used to store some information in
         * the ParserOutput object for later use during page output. The data will be cached along with
         * the ParserOutput object, but unlike data set using setPageProperty(), it is not recorded in the
         * database.
         *
         * This method is provided to overcome the unsafe practice of attaching extra information to a
         * ParserObject by directly assigning member variables.
         *
         * To use setExtensionData() to pass extension information from a hook inside the parser to a
         * hook in the page output, use this in the parser hook:
         *
         * @par Example:
         * @code
         *    $parser->getOutput()->setExtensionData( 'my_ext_foo', '...' );
         * @endcode
         *
         * And then later, in OutputPageParserOutput or similar:
         *
         * @par Example:
         * @code
         *    $output->getExtensionData( 'my_ext_foo' );
         * @endcode
         *
         * In MediaWiki 1.20 and older, you have to use a custom member variable
         * within the ParserOutput object:
         *
         * @par Example:
         * @code
         *    $parser->getOutput()->my_ext_foo = '...';
         * @endcode
         *
         * @note Only scalar values, e.g. numbers, strings, arrays or MediaWiki\Json\JsonDeserializable
         * instances are supported as a value. Attempt to set other class instance as extension data
         * will break ParserCache for the page.
         *
         * @note Since MW 1.38 the practice of setting conflicting values for
         * the same key has been deprecated.  As with ::setJsConfigVar(), if
         * you set the same key multiple times on a ParserOutput, it is expected
         * that the value will be identical each time.  If you want to collect
         * multiple pieces of data under a single key, use ::appendExtensionData().
         *
         * @param string $key The key for accessing the data. Extensions should take care to avoid
         *   conflicts in naming keys. It is suggested to use the extension's name as a prefix.
         *
         * @param mixed|JsonDeserializable $value The value to set.
         *   Setting a value to null is equivalent to removing the value.
         * @since 1.21
         */
        public function setExtensionData( $key, $value ): void {
                if (
                        array_key_exists( $key, $this->mExtensionData ) &&
                        $this->mExtensionData[$key] !== $value
                ) {
                        // This behavior was deprecated in 1.38.  We will eventually
                        // emit a warning here, then throw an exception.
                }
                if ( $value === null ) {
                        unset( $this->mExtensionData[$key] );
                } else {
                        $this->mExtensionData[$key] = $value;
                }
        }

        /**
         * Appends arbitrary data to this ParserObject. This can be used
         * to store some information in the ParserOutput object for later
         * use during page output. The data will be cached along with the
         * ParserOutput object, but unlike data set using
         * setPageProperty(), it is not recorded in the database.
         *
         * See ::setExtensionData() for more details on rationale and use.
         *
         * In order to provide for out-of-order/asynchronous/incremental
         * parsing, this method appends values to a set.  See
         * ::setExtensionData() for the flag-like version of this method.
         *
         * @note Only values which can be array keys are currently supported
         * as values.
         *
         * @param string $key The key for accessing the data. Extensions should take care to avoid
         *   conflicts in naming keys. It is suggested to use the extension's name as a prefix.
         *
         * @param int|string $value The value to append to the list.
         * @param string $strategy Merge strategy:
         *  only MW_MERGE_STRATEGY_UNION is currently supported and external callers
         *  should treat this parameter as @internal at this time and omit it.
         * @since 1.38
         */
        public function appendExtensionData(
                string $key,
                $value,
                string $strategy = self::MW_MERGE_STRATEGY_UNION
        ): void {
                if ( $strategy !== self::MW_MERGE_STRATEGY_UNION ) {
                        throw new InvalidArgumentException( "Unknown merge strategy $strategy." );
                }
                if ( !array_key_exists( $key, $this->mExtensionData ) ) {
                        $this->mExtensionData[$key] = [
                                // Indicate how these values are to be merged.
                                self::MW_MERGE_STRATEGY_KEY => $strategy,
                        ];
                } elseif ( !is_array( $this->mExtensionData[$key] ) ) {
                        throw new InvalidArgumentException( "Mixing set and append for $key" );
                } elseif ( ( $this->mExtensionData[$key][self::MW_MERGE_STRATEGY_KEY] ?? null ) !== $strategy ) {
                        throw new InvalidArgumentException( "Conflicting merge strategies for $key" );
                }
                $this->mExtensionData[$key][$value] = true;
        }

        /**
         * Gets extensions data previously attached to this ParserOutput using setExtensionData().
         * Typically, such data would be set while parsing the page, e.g. by a parser function.
         *
         * @since 1.21
         *
         * @param string $key The key to look up.
         *
         * @return mixed|null The value previously set for the given key using setExtensionData()
         *         or null if no value was set for this key.
         */
        public function getExtensionData( $key ) {
                $value = $this->mExtensionData[$key] ?? null;
                if ( is_array( $value ) ) {
                        // Don't expose our internal merge strategy key.
                        unset( $value[self::MW_MERGE_STRATEGY_KEY] );
                }
                return $value;
        }

        private static function getTimes( $clock = null ): array {
                $ret = [];
                if ( !$clock || $clock === 'wall' ) {
                        $ret['wall'] = microtime( true );
                }
                if ( !$clock || $clock === 'cpu' ) {
                        $ru = getrusage( 0 /* RUSAGE_SELF */ );
                        $ret['cpu'] = $ru['ru_utime.tv_sec'] + $ru['ru_utime.tv_usec'] / 1e6;
                        $ret['cpu'] += $ru['ru_stime.tv_sec'] + $ru['ru_stime.tv_usec'] / 1e6;
                }
                return $ret;
        }

        /**
         * Resets the parse start timestamps for future calls to getTimeSinceStart()
         * and recordTimeProfile().
         *
         * @since 1.22
         */
        public function resetParseStartTime(): void {
                $this->mParseStartTime = self::getTimes();
                $this->mTimeProfile = [];
        }

        /**
         * Unset the parse start time.
         *
         * This is intended for testing purposes only, in order to avoid
         * spurious differences between testing outputs created at different
         * times.
         *
         * @since 1.43
         */
        public function clearParseStartTime(): void {
                $this->mParseStartTime = [];
        }

        /**
         * Record the time since resetParseStartTime() was last called.
         * The recorded time can be accessed using getTimeProfile().
         *
         * After resetParseStartTime() was called, the first call to recordTimeProfile()
         * will record the time profile. Subsequent calls to recordTimeProfile() will have
         * no effect until resetParseStartTime() is called again.
         *
         * @since 1.42
         */
        public function recordTimeProfile() {
                if ( !$this->mParseStartTime ) {
                        // If resetParseStartTime was never called, there is nothing to record
                        return;
                }

                if ( $this->mTimeProfile !== [] ) {
                        // Don't override the times recorded by the previous call to recordTimeProfile().
                        return;
                }

                $now = self::getTimes();
                $this->mTimeProfile = [
                        'wall' => $now['wall'] - $this->mParseStartTime['wall'],
                        'cpu' => $now['cpu'] - $this->mParseStartTime['cpu'],
                ];
        }

        /**
         * Returns the time that elapsed between the most recent call to resetParseStartTime()
         * and the first call to recordTimeProfile() after that.
         *
         * Clocks available are:
         *  - wall: Wall clock time
         *  - cpu: CPU time (requires getrusage)
         *
         * If recordTimeProfile() has noit been called since the most recent call to
         * resetParseStartTime(), or if resetParseStartTime() was never called, then
         * this method will return null.
         *
         * @param string $clock
         *
         * @since 1.42
         * @return float|null
         */
        public function getTimeProfile( string $clock ) {
                return $this->mTimeProfile[ $clock ] ?? null;
        }

        /**
         * Returns the time since resetParseStartTime() was last called
         *
         * Clocks available are:
         *  - wall: Wall clock time
         *  - cpu: CPU time (requires getrusage)
         *
         * @since 1.22
         * @deprecated since 1.42, use getTimeProfile() instead.
         * @param string $clock
         * @return float|null
         */
        public function getTimeSinceStart( $clock ) {
                wfDeprecated( __METHOD__, '1.42' );

                if ( !isset( $this->mParseStartTime[$clock] ) ) {
                        return null;
                }

                $end = self::getTimes( $clock );
                return $end[$clock] - $this->mParseStartTime[$clock];
        }

        /**
         * Sets parser limit report data for a key
         *
         * The key is used as the prefix for various messages used for formatting:
         *  - $key: The label for the field in the limit report
         *  - $key-value-text: Message used to format the value in the "NewPP limit
         *      report" HTML comment. If missing, uses $key-format.
         *  - $key-value-html: Message used to format the value in the preview
         *      limit report table. If missing, uses $key-format.
         *  - $key-value: Message used to format the value. If missing, uses "$1".
         *
         * Note that all values are interpreted as wikitext, and so should be
         * encoded with htmlspecialchars() as necessary, but should avoid complex
         * HTML for display in the "NewPP limit report" comment.
         *
         * @since 1.22
         * @param string $key Message key
         * @param mixed $value Appropriate for Message::params()
         */
        public function setLimitReportData( $key, $value ): void {
                $this->mLimitReportData[$key] = $value;

                if ( is_array( $value ) ) {
                        if ( array_keys( $value ) === [ 0, 1 ]
                                && is_numeric( $value[0] )
                                && is_numeric( $value[1] )
                        ) {
                                $data = [ 'value' => $value[0], 'limit' => $value[1] ];
                        } else {
                                $data = $value;
                        }
                } else {
                        $data = $value;
                }

                if ( strpos( $key, '-' ) ) {
                        [ $ns, $name ] = explode( '-', $key, 2 );
                        $this->mLimitReportJSData[$ns][$name] = $data;
                } else {
                        $this->mLimitReportJSData[$key] = $data;
                }
        }

        /**
         * Check whether the cache TTL was lowered from the site default.
         *
         * When content is determined by more than hard state (e.g. page edits),
         * such as template/file transclusions based on the current timestamp or
         * extension tags that generate lists based on queries, this return true.
         *
         * This method mainly exists to facilitate the logic in
         * WikiPage::triggerOpportunisticLinksUpdate. As such, beware that reducing the TTL for
         * reasons that do not relate to "dynamic content", may have the side-effect of incurring
         * more RefreshLinksJob executions.
         *
         * @internal For use by Parser and WikiPage
         * @since 1.37
         * @return bool
         */
        public function hasReducedExpiry(): bool {
                $parserCacheExpireTime = MediaWikiServices::getInstance()->getMainConfig()->get(
                        MainConfigNames::ParserCacheExpireTime );

                return $this->getCacheExpiry() < $parserCacheExpireTime;
        }

        /**
         * Set the prevent-clickjacking flag.  If set this will cause an
         * `X-Frame-Options` header appropriate for edit pages to be sent.
         * The header value is controlled by `$wgEditPageFrameOptions`.
         *
         * This is the default for special pages.  If you display a CSRF-protected
         * form on an ordinary view page, then you need to call this function
         * with `$flag = true`.
         *
         * @param bool $flag New flag value
         * @since 1.38
         */
        public function setPreventClickjacking( bool $flag ): void {
                $this->mPreventClickjacking = $flag;
        }

        /**
         * Get the prevent-clickjacking flag.
         *
         * @return bool Flag value
         * @since 1.38
         * @see ::setPreventClickjacking
         */
        public function getPreventClickjacking(): bool {
                return $this->mPreventClickjacking;
        }

        /**
         * Lower the runtime adaptive TTL to at most this value
         *
         * @param int $ttl
         * @since 1.28
         */
        public function updateRuntimeAdaptiveExpiry( $ttl ): void {
                $this->mMaxAdaptiveExpiry = min( $ttl, $this->mMaxAdaptiveExpiry );
                $this->updateCacheExpiry( $ttl );
        }

        /**
         * Add an extra value to Content-Security-Policy default-src directive
         *
         * Call this if you are including a resource (e.g. image) from a third party domain.
         * This is used for all source types except style and script.
         *
         * @since 1.35
         * @param string $src CSP source e.g. example.com
         */
        public function addExtraCSPDefaultSrc( $src ): void {
                $this->mExtraDefaultSrcs[] = $src;
        }

        /**
         * Add an extra value to Content-Security-Policy style-src directive
         *
         * @since 1.35
         * @param string $src CSP source e.g. example.com
         */
        public function addExtraCSPStyleSrc( $src ): void {
                $this->mExtraStyleSrcs[] = $src;
        }

        /**
         * Add an extra value to Content-Security-Policy script-src directive
         *
         * Call this if you are loading third-party Javascript
         *
         * @since 1.35
         * @param string $src CSP source e.g. example.com
         */
        public function addExtraCSPScriptSrc( $src ): void {
                $this->mExtraScriptSrcs[] = $src;
        }

        /**
         * Call this when parsing is done to lower the TTL based on low parse times
         *
         * @since 1.28
         */
        public function finalizeAdaptiveCacheExpiry(): void {
                if ( is_infinite( $this->mMaxAdaptiveExpiry ) ) {
                        return; // not set
                }

                $runtime = $this->getTimeProfile( 'wall' );
                if ( is_float( $runtime ) ) {
                        $slope = ( self::SLOW_AR_TTL - self::FAST_AR_TTL )
                                / ( self::PARSE_SLOW_SEC - self::PARSE_FAST_SEC );
                        // SLOW_AR_TTL = PARSE_SLOW_SEC * $slope + $point
                        $point = self::SLOW_AR_TTL - self::PARSE_SLOW_SEC * $slope;

                        $adaptiveTTL = min(
                                max( $slope * $runtime + $point, self::MIN_AR_TTL ),
                                $this->mMaxAdaptiveExpiry
                        );
                        $this->updateCacheExpiry( $adaptiveTTL );
                }
        }

        /**
         * Transfer parser options which affect post-processing from ParserOptions
         * to this ParserOutput.
         * @param ParserOptions $parserOptions
         */
        public function setFromParserOptions( ParserOptions $parserOptions ) {
                // Copied from Parser.php::parse and should probably be abstracted
                // into the parent base class (probably as part of T236809)
                // Wrap non-interface parser output in a <div> so it can be targeted
                // with CSS (T37247)
                $class = $parserOptions->getWrapOutputClass();
                if ( $class !== false && !$parserOptions->getInterfaceMessage() ) {
                        $this->addWrapperDivClass( $class );
                }

                // Record whether we should suppress section edit links
                if ( $parserOptions->getSuppressSectionEditLinks() ) {
                        $this->setOutputFlag( ParserOutputFlags::NO_SECTION_EDIT_LINKS );
                }

                // Record whether we should wrap sections for collapsing them
                if ( $parserOptions->getCollapsibleSections() ) {
                        $this->setOutputFlag( ParserOutputFlags::COLLAPSIBLE_SECTIONS );
                }

                // Record whether this is a preview parse in the output (T341010)
                if ( $parserOptions->getIsPreview() ) {
                        $this->setOutputFlag( ParserOutputFlags::IS_PREVIEW, true );
                        // Ensure that previews aren't cacheable, just to be safe.
                        $this->updateCacheExpiry( 0 );
                }
        }

        public function __sleep() {
                return array_filter( array_keys( get_object_vars( $this ) ),
                        static function ( $field ) {
                                if ( $field === 'mParseStartTime' || $field === 'mWarningMsgs' ) {
                                        return false;
                                }
                                // Unserializing unknown private fields in HHVM causes
                                // member variables with nulls in their names (T229366)
                                return strpos( $field, "\0" ) === false;
                        }
                );
        }

        /**
         * Merges internal metadata such as flags, accessed options, and profiling info
         * from $source into this ParserOutput. This should be used whenever the state of $source
         * has any impact on the state of this ParserOutput.
         *
         * @param ParserOutput $source
         */
        public function mergeInternalMetaDataFrom( ParserOutput $source ): void {
                $this->mWarnings = self::mergeMap( $this->mWarnings, $source->mWarnings ); // don't use getter
                $this->mTimestamp = $this->useMaxValue( $this->mTimestamp, $source->getRevisionTimestamp() );
                if ( $source->hasCacheTime() ) {
                        $sourceCacheTime = $source->getCacheTime();
                        if (
                                !$this->hasCacheTime() ||
                                // "undocumented use of -1 to mean not cacheable"
                                // deprecated, but still supported by ::setCacheTime()
                                strval( $sourceCacheTime ) === '-1' ||
                                (
                                        strval( $this->getCacheTime() ) !== '-1' &&
                                        // use newer of the two times
                                        $this->getCacheTime() < $sourceCacheTime
                                )
                        ) {
                                $this->setCacheTime( $sourceCacheTime );
                        }
                }
                if ( $source->getRenderId() !== null ) {
                        // Final render ID should be a function of all component POs
                        $rid = ( $this->getRenderId() ?? '' ) . $source->getRenderId();
                        $this->setRenderId( $rid );
                }
                if ( $source->getCacheRevisionId() !== null ) {
                        $sourceCacheRevisionId = $source->getCacheRevisionId();
                        $thisCacheRevisionId = $this->getCacheRevisionId();
                        if ( $thisCacheRevisionId === null ) {
                                $this->setCacheRevisionId( $sourceCacheRevisionId );
                        } elseif ( $sourceCacheRevisionId !== $thisCacheRevisionId ) {
                                // May throw an exception here in the future
                                wfDeprecated(
                                        __METHOD__ . ": conflicting revision IDs " .
                                        "$thisCacheRevisionId and $sourceCacheRevisionId"
                                );
                        }
                }

                foreach ( self::SPECULATIVE_FIELDS as $field ) {
                        if ( $this->$field && $source->$field && $this->$field !== $source->$field ) {
                                wfLogWarning( __METHOD__ . ": inconsistent '$field' properties!" );
                        }
                        $this->$field = $this->useMaxValue( $this->$field, $source->$field );
                }

                $this->mParseStartTime = $this->useEachMinValue(
                        $this->mParseStartTime,
                        $source->mParseStartTime
                );

                $this->mTimeProfile = $this->useEachTotalValue(
                        $this->mTimeProfile,
                        $source->mTimeProfile
                );

                $this->mFlags = self::mergeMap( $this->mFlags, $source->mFlags );
                $this->mParseUsedOptions = self::mergeMap( $this->mParseUsedOptions, $source->mParseUsedOptions );

                // TODO: maintain per-slot limit reports!
                if ( !$this->mLimitReportData ) {
                        $this->mLimitReportData = $source->mLimitReportData;
                }
                if ( !$this->mLimitReportJSData ) {
                        $this->mLimitReportJSData = $source->mLimitReportJSData;
                }
        }

        /**
         * Merges HTML metadata such as head items, JS config vars, and HTTP cache control info
         * from $source into this ParserOutput. This should be used whenever the HTML in $source
         * has been somehow merged into the HTML of this ParserOutput.
         *
         * @param ParserOutput $source
         */
        public function mergeHtmlMetaDataFrom( ParserOutput $source ): void {
                // HTML and HTTP
                $this->mHeadItems = self::mergeMixedList( $this->mHeadItems, $source->getHeadItems() );
                $this->addModules( $source->getModules() );
                $this->addModuleStyles( $source->getModuleStyles() );
                $this->mJsConfigVars = self::mergeMapStrategy( $this->mJsConfigVars, $source->mJsConfigVars );
                $this->mMaxAdaptiveExpiry = min( $this->mMaxAdaptiveExpiry, $source->mMaxAdaptiveExpiry );
                $this->mExtraStyleSrcs = self::mergeList(
                        $this->mExtraStyleSrcs,
                        $source->getExtraCSPStyleSrcs()
                );
                $this->mExtraScriptSrcs = self::mergeList(
                        $this->mExtraScriptSrcs,
                        $source->getExtraCSPScriptSrcs()
                );
                $this->mExtraDefaultSrcs = self::mergeList(
                        $this->mExtraDefaultSrcs,
                        $source->getExtraCSPDefaultSrcs()
                );

                // "noindex" always wins!
                $this->mIndexSet = $this->mIndexSet || $source->mIndexSet;
                $this->mNoIndexSet = $this->mNoIndexSet || $source->mNoIndexSet;

                // Skin control
                $this->mNewSection = $this->mNewSection || $source->getNewSection();
                $this->mHideNewSection = $this->mHideNewSection || $source->getHideNewSection();
                $this->mNoGallery = $this->mNoGallery || $source->getNoGallery();
                $this->mEnableOOUI = $this->mEnableOOUI || $source->getEnableOOUI();
                $this->mPreventClickjacking = $this->mPreventClickjacking || $source->getPreventClickjacking();

                $tocData = $this->getTOCData();
                $sourceTocData = $source->getTOCData();
                if ( $tocData !== null ) {
                        if ( $sourceTocData !== null ) {
                                // T327429: Section merging is broken, since it doesn't respect
                                // global numbering, but there are tests which expect section
                                // metadata to be concatenated.
                                // There should eventually be a deprecation warning here.
                                foreach ( $sourceTocData->getSections() as $s ) {
                                        $tocData->addSection( $s );
                                }
                        }
                } elseif ( $sourceTocData !== null ) {
                        $this->setTOCData( $sourceTocData );
                }

                // XXX: we don't want to concatenate title text, so first write wins.
                // We should use the first *modified* title text, but we don't have the original to check.
                if ( $this->mTitleText === null || $this->mTitleText === '' ) {
                        $this->mTitleText = $source->mTitleText;
                }

                // class names are stored in array keys
                $this->mWrapperDivClasses = self::mergeMap(
                        $this->mWrapperDivClasses,
                        $source->mWrapperDivClasses
                );

                // NOTE: last write wins, same as within one ParserOutput
                $this->mIndicators = self::mergeMap( $this->mIndicators, $source->getIndicators() );

                // NOTE: include extension data in "tracking meta data" as well as "html meta data"!
                // TODO: add a $mergeStrategy parameter to setExtensionData to allow different
                // kinds of extension data to be merged in different ways.
                $this->mExtensionData = self::mergeMapStrategy(
                        $this->mExtensionData,
                        $source->mExtensionData
                );
        }

        /**
         * Merges dependency tracking metadata such as backlinks, images used, and extension data
         * from $source into this ParserOutput. This allows dependency tracking to be done for the
         * combined output of multiple content slots.
         *
         * @param ParserOutput $source
         */
        public function mergeTrackingMetaDataFrom( ParserOutput $source ): void {
                foreach (
                        $source->getLinkList( ParserOutputLinkTypes::LANGUAGE )
                        as [ 'link' => $link ]
                ) {
                        $this->addLanguageLink( $link );
                }
                $this->mCategories = self::mergeMap( $this->mCategories, $source->getCategoryMap() );
                foreach (
                        $source->getLinkList( ParserOutputLinkTypes::LOCAL )
                        as [ 'link' => $link, 'pageid' => $pageid ]
                ) {
                        $this->addLink( $link, $pageid );
                }
                foreach (
                        $source->getLinkList( ParserOutputLinkTypes::TEMPLATE )
                                as [ 'link' => $link, 'pageid' => $pageid, 'revid' => $revid ]
                ) {
                        $this->addTemplate( $link, $pageid, $revid );
                }
                foreach (
                        $source->getLinkList( ParserOutputLinkTypes::MEDIA ) as $item
                ) {
                        $this->addImage( $item['link'], $item['time'] ?? null, $item['sha1'] ?? null );
                }
                $this->mExternalLinks = self::mergeMap( $this->mExternalLinks, $source->getExternalLinks() );
                foreach (
                        $source->getLinkList( ParserOutputLinkTypes::INTERWIKI )
                        as [ 'link' => $link ]
                ) {
                        $this->addInterwikiLink( $link );
                }

                foreach (
                        $source->getLinkList( ParserOutputLinkTypes::SPECIAL )
                        as [ 'link' => $link ]
                ) {
                        $this->addLink( $link );
                }

                // TODO: add a $mergeStrategy parameter to setPageProperty to allow different
                // kinds of properties to be merged in different ways.
                // (Model this after ::appendJsConfigVar(); use ::mergeMapStrategy here)
                $this->mProperties = self::mergeMap( $this->mProperties, $source->getPageProperties() );

                // NOTE: include extension data in "tracking meta data" as well as "html meta data"!
                $this->mExtensionData = self::mergeMapStrategy(
                        $this->mExtensionData,
                        $source->mExtensionData
                );
        }

        /**
         * Adds the metadata collected in this ParserOutput to the supplied
         * ContentMetadataCollector.  This is similar to ::mergeHtmlMetaDataFrom()
         * but in the opposite direction, since ParserOutput is read/write while
         * ContentMetadataCollector is write-only.
         *
         * @param ContentMetadataCollector $metadata
         * @since 1.38
         */
        public function collectMetadata( ContentMetadataCollector $metadata ): void {
                // Uniform handling of all boolean flags: they are OR'ed together.
                $flags = array_keys(
                        $this->mFlags + array_flip( ParserOutputFlags::cases() )
                );
                foreach ( $flags as $name ) {
                        if ( $this->getOutputFlag( $name ) ) {
                                $metadata->setOutputFlag( $name );
                        }
                }

                // Uniform handling of string sets: they are unioned.
                // (This includes modules, style modes, and CSP src.)
                foreach ( ParserOutputStringSets::cases() as $name ) {
                        $metadata->appendOutputStrings(
                                $name, $this->getOutputStrings( $name )
                        );
                }

                foreach ( $this->mCategories as $cat => $key ) {
                        // Numeric category strings are going to come out of the
                        // `mCategories` array as ints; cast back to string.
                        // Also convert back to a LinkTarget!
                        $lt = TitleValue::tryNew( NS_CATEGORY, (string)$cat );
                        $metadata->addCategory( $lt, $key );
                }

                foreach ( $this->mLinks as $ns => $arr ) {
                        foreach ( $arr as $dbk => $id ) {
                                // Numeric titles are going to come out of the
                                // `mLinks` array as ints; cast back to string.
                                $lt = TitleValue::tryNew( $ns, (string)$dbk );
                                $metadata->addLink( $lt, $id );
                        }
                }

                foreach ( $this->mInterwikiLinks as $prefix => $arr ) {
                        foreach ( $arr as $dbk => $ignore ) {
                                $lt = TitleValue::tryNew( NS_MAIN, (string)$dbk, '', $prefix );
                                $metadata->addLink( $lt );
                        }
                }

                foreach ( $this->mLinksSpecial as $dbk => $ignore ) {
                        // Numeric titles are going to come out of the
                        // `mLinks` array as ints; cast back to string.
                        $lt = TitleValue::tryNew( NS_SPECIAL, (string)$dbk );
                        $metadata->addLink( $lt );
                }

                foreach ( $this->mImages as $name => $ignore ) {
                        // Numeric titles come out of mImages as ints.
                        $lt = TitleValue::tryNew( NS_FILE, (string)$name );
                        $props = $this->mFileSearchOptions[$name] ?? [];
                        $metadata->addImage( $lt, $props['time'] ?? null, $props['sha1'] ?? null );
                }

                foreach ( $this->mLanguageLinkMap as $lang => $title ) {
                        if ( $title === '|' ) {
                                continue; // T374736: not a valid language link
                        }
                        # language links can have fragments!
                        [ $title, $frag ] = array_pad( explode( '#', $title, 2 ), 2, '' );
                        $lt = TitleValue::tryNew( NS_MAIN, $title, $frag, (string)$lang );
                        $metadata->addLanguageLink( $lt );
                }

                foreach ( $this->mJsConfigVars as $key => $value ) {
                        if ( is_array( $value ) && isset( $value[self::MW_MERGE_STRATEGY_KEY] ) ) {
                                $strategy = $value[self::MW_MERGE_STRATEGY_KEY];
                                foreach ( $value as $item => $ignore ) {
                                        if ( $item !== self::MW_MERGE_STRATEGY_KEY ) {
                                                $metadata->appendJsConfigVar( $key, $item, $strategy );
                                        }
                                }
                        } elseif ( $metadata instanceof ParserOutput &&
                                array_key_exists( $key, $metadata->mJsConfigVars )
                        ) {
                                // This behavior is deprecated, will likely result in
                                // incorrect output, and we'll eventually emit a
                                // warning here---but at the moment this is usually
                                // caused by limitations in Parsoid and/or use of
                                // the ParserAfterParse hook: T303015#7770480
                                $metadata->mJsConfigVars[$key] = $value;
                        } else {
                                $metadata->setJsConfigVar( $key, $value );
                        }
                }
                foreach ( $this->mExtensionData as $key => $value ) {
                        if ( is_array( $value ) && isset( $value[self::MW_MERGE_STRATEGY_KEY] ) ) {
                                $strategy = $value[self::MW_MERGE_STRATEGY_KEY];
                                foreach ( $value as $item => $ignore ) {
                                        if ( $item !== self::MW_MERGE_STRATEGY_KEY ) {
                                                $metadata->appendExtensionData( $key, $item, $strategy );
                                        }
                                }
                        } elseif ( $metadata instanceof ParserOutput &&
                                array_key_exists( $key, $metadata->mExtensionData )
                        ) {
                                // This behavior is deprecated, will likely result in
                                // incorrect output, and we'll eventually emit a
                                // warning here---but at the moment this is usually
                                // caused by limitations in Parsoid and/or use of
                                // the ParserAfterParse hook: T303015#7770480
                                $metadata->mExtensionData[$key] = $value;
                        } else {
                                $metadata->setExtensionData( $key, $value );
                        }
                }
                foreach ( $this->mExternalLinks as $url => $ignore ) {
                        $metadata->addExternalLink( $url );
                }
                foreach ( $this->mProperties as $prop => $value ) {
                        if ( is_numeric( $value ) ) {
                                $metadata->setNumericPageProperty( $prop, $value );
                        } elseif ( is_string( $value ) ) {
                                $metadata->setUnsortedPageProperty( $prop, $value );
                        } else {
                                // Deprecated, but there are still sites which call
                                // ::setPageProperty() with "unusual" values (T374046)
                                $metadata->setPageProperty( $prop, $value );
                        }
                }
                foreach ( $this->mWarningMsgs as $msg => $args ) {
                        $metadata->addWarningMsg( $msg, ...$args );
                }
                foreach ( $this->mLimitReportData as $key => $value ) {
                        $metadata->setLimitReportData( $key, $value );
                }
                foreach ( $this->mIndicators as $id => $content ) {
                        $metadata->setIndicator( $id, $content );
                }

                // ParserOutput-only fields; maintained "behind the curtain"
                // since Parsoid doesn't have to know about them.
                //
                // In production use, the $metadata supplied to this method
                // will almost always be an instance of ParserOutput, passed to
                // Parsoid by core when parsing begins and returned to core by
                // Parsoid as a ContentMetadataCollector (Parsoid's name for
                // ParserOutput) when DataAccess::parseWikitext() is called.
                //
                // We may use still Parsoid's StubMetadataCollector for testing or
                // when running Parsoid in standalone mode, so forcing a downcast
                // here would lose some flexibility.

                if ( $metadata instanceof ParserOutput ) {
                        foreach ( $this->getUsedOptions() as $opt ) {
                                $metadata->recordOption( $opt );
                        }
                        if ( $this->mCacheExpiry !== null ) {
                                $metadata->updateCacheExpiry( $this->mCacheExpiry );
                        }
                        if ( $this->mCacheTime !== '' ) {
                                $metadata->setCacheTime( $this->mCacheTime );
                        }
                        if ( $this->mCacheRevisionId !== null ) {
                                $metadata->setCacheRevisionId( $this->mCacheRevisionId );
                        }
                        // T293514: We should use the first *modified* title text, but
                        // we don't have the original to check.
                        $otherTitle = $metadata->getTitleText();
                        if ( $otherTitle === null || $otherTitle === '' ) {
                                $metadata->setTitleText( $this->getTitleText() );
                        }
                        foreach ( $this->mTemplates as $ns => $arr ) {
                                foreach ( $arr as $dbk => $page_id ) {
                                        // default to invalid/broken revision if this is not present
                                        $rev_id = $this->mTemplateIds[$ns][$dbk] ?? 0;
                                        $metadata->addTemplate( TitleValue::tryNew( $ns, (string)$dbk ), $page_id, $rev_id );
                                }
                        }
                }
        }

        private static function mergeMixedList( array $a, array $b ): array {
                return array_unique( array_merge( $a, $b ), SORT_REGULAR );
        }

        private static function mergeList( array $a, array $b ): array {
                return array_values( array_unique( array_merge( $a, $b ), SORT_REGULAR ) );
        }

        private static function mergeMap( array $a, array $b ): array {
                return array_replace( $a, $b );
        }

        private static function mergeMapStrategy( array $a, array $b ): array {
                foreach ( $b as $key => $bValue ) {
                        if ( !array_key_exists( $key, $a ) ) {
                                $a[$key] = $bValue;
                        } elseif (
                                is_array( $a[$key] ) &&
                                isset( $a[$key][self::MW_MERGE_STRATEGY_KEY] ) &&
                                isset( $bValue[self::MW_MERGE_STRATEGY_KEY] )
                        ) {
                                $strategy = $bValue[self::MW_MERGE_STRATEGY_KEY];
                                if ( $strategy !== $a[$key][self::MW_MERGE_STRATEGY_KEY] ) {
                                        throw new InvalidArgumentException( "Conflicting merge strategy for $key" );
                                }
                                if ( $strategy === self::MW_MERGE_STRATEGY_UNION ) {
                                        // Note the array_merge is *not* safe to use here, because
                                        // the $bValue is expected to be a map from items to `true`.
                                        // If the item is a numeric string like '1' then array_merge
                                        // will convert it to an integer and renumber the array!
                                        $a[$key] = array_replace( $a[$key], $bValue );
                                } else {
                                        throw new InvalidArgumentException( "Unknown merge strategy $strategy" );
                                }
                        } else {
                                $valuesSame = ( $a[$key] === $bValue );
                                if ( ( !$valuesSame ) &&
                                        is_object( $a[$key] ) &&
                                        is_object( $bValue )
                                ) {
                                        $jsonCodec = MediaWikiServices::getInstance()->getJsonCodec();
                                        $valuesSame = ( $jsonCodec->serialize( $a[$key] ) === $jsonCodec->serialize( $bValue ) );
                                }
                                if ( !$valuesSame ) {
                                        // Silently replace for now; in the future will first emit
                                        // a deprecation warning, and then (later) throw.
                                        $a[$key] = $bValue;
                                }
                        }
                }
                return $a;
        }

        private static function useEachMinValue( array $a, array $b ): array {
                $values = [];
                $keys = array_merge( array_keys( $a ), array_keys( $b ) );

                foreach ( $keys as $k ) {
                        $values[$k] = min( $a[$k] ?? INF, $b[$k] ?? INF );
                }

                return $values;
        }

        private static function useEachTotalValue( array $a, array $b ): array {
                $values = [];
                $keys = array_merge( array_keys( $a ), array_keys( $b ) );

                foreach ( $keys as $k ) {
                        $values[$k] = ( $a[$k] ?? 0 ) + ( $b[$k] ?? 0 );
                }

                return $values;
        }

        private static function useMaxValue( $a, $b ) {
                if ( $a === null ) {
                        return $b;
                }

                if ( $b === null ) {
                        return $a;
                }

                return max( $a, $b );
        }

        /**
         * Returns a JSON serializable structure representing this ParserOutput instance.
         * @see newFromJson()
         *
         * @return array
         */
        protected function toJsonArray(): array {
                // WARNING: When changing how this class is serialized, follow the instructions
                // at <https://www.mediawiki.org/wiki/Manual:Parser_cache/Serialization_compatibility>!

                $data = [
                        'Text' => $this->mRawText,
                        'LanguageLinks' => $this->getLanguageLinks(),
                        'Categories' => $this->mCategories,
                        'Indicators' => $this->mIndicators,
                        'TitleText' => $this->mTitleText,
                        'Links' => $this->mLinks,
                        'LinksSpecial' => $this->mLinksSpecial,
                        'Templates' => $this->mTemplates,
                        'TemplateIds' => $this->mTemplateIds,
                        'Images' => $this->mImages,
                        'FileSearchOptions' => $this->mFileSearchOptions,
                        'ExternalLinks' => $this->mExternalLinks,
                        'InterwikiLinks' => $this->mInterwikiLinks,
                        'NewSection' => $this->mNewSection,
                        'HideNewSection' => $this->mHideNewSection,
                        'NoGallery' => $this->mNoGallery,
                        'HeadItems' => $this->mHeadItems,
                        'Modules' => array_keys( $this->mModuleSet ),
                        'ModuleStyles' => array_keys( $this->mModuleStyleSet ),
                        'JsConfigVars' => $this->mJsConfigVars,
                        'Warnings' => $this->mWarnings,
                        'Sections' => $this->getSections(),
                        'Properties' => self::detectAndEncodeBinary( $this->mProperties ),
                        'Timestamp' => $this->mTimestamp,
                        'EnableOOUI' => $this->mEnableOOUI,
                        'IndexPolicy' => $this->getIndexPolicy(),
                        // may contain arbitrary structures!
                        'ExtensionData' => $this->mExtensionData,
                        'LimitReportData' => $this->mLimitReportData,
                        'LimitReportJSData' => $this->mLimitReportJSData,
                        'CacheMessage' => $this->mCacheMessage,
                        'TimeProfile' => $this->mTimeProfile,
                        'ParseStartTime' => [], // don't serialize this
                        'PreventClickjacking' => $this->mPreventClickjacking,
                        'ExtraScriptSrcs' => $this->mExtraScriptSrcs,
                        'ExtraDefaultSrcs' => $this->mExtraDefaultSrcs,
                        'ExtraStyleSrcs' => $this->mExtraStyleSrcs,
                        'Flags' => $this->mFlags + (
                                // backward-compatibility: distinguish "no sections" from
                                // "sections not set" (Will be unnecessary after T327439.)
                                $this->mTOCData === null ? [] : [ 'mw:toc-set' => true ]
                        ),
                        'SpeculativeRevId' => $this->mSpeculativeRevId,
                        'SpeculativePageIdUsed' => $this->speculativePageIdUsed,
                        'RevisionTimestampUsed' => $this->revisionTimestampUsed,
                        'RevisionUsedSha1Base36' => $this->revisionUsedSha1Base36,
                        'WrapperDivClasses' => $this->mWrapperDivClasses,
                ];

                // Fill in missing fields from parents. Array addition does not override existing fields.
                $data += parent::toJsonArray();

                // TODO: make more fields optional!

                if ( $this->mMaxAdaptiveExpiry !== INF ) {
                        // NOTE: JSON can't encode infinity!
                        $data['MaxAdaptiveExpiry'] = $this->mMaxAdaptiveExpiry;
                }

                if ( $this->mTOCData ) {
                        // Temporarily add information from TOCData extension data
                        // T327439: We should eventually make the entire mTOCData
                        // serializable
                        $toc = $this->mTOCData->jsonSerialize();
                        if ( isset( $toc['extensionData'] ) ) {
                                $data['TOCExtensionData'] = $toc['extensionData'];
                        }
                }

                return $data;
        }

        public static function newFromJsonArray( JsonDeserializer $deserializer, array $json ): ParserOutput {
                $parserOutput = new ParserOutput();
                $parserOutput->initFromJson( $deserializer, $json );
                return $parserOutput;
        }

        /**
         * Initialize member fields from an array returned by jsonSerialize().
         * @param JsonDeserializer $deserializer
         * @param array $jsonData
         */
        protected function initFromJson( JsonDeserializer $deserializer, array $jsonData ): void {
                parent::initFromJson( $deserializer, $jsonData );

                // WARNING: When changing how this class is serialized, follow the instructions
                // at <https://www.mediawiki.org/wiki/Manual:Parser_cache/Serialization_compatibility>!

                $this->mRawText = $jsonData['Text'];
                $this->mLanguageLinkMap = [];
                foreach ( ( $jsonData['LanguageLinks'] ?? [] ) as $l ) {
                        $this->addLanguageLink( $l );
                }
                $this->mCategories = $jsonData['Categories'];
                $this->mIndicators = $jsonData['Indicators'];
                $this->mTitleText = $jsonData['TitleText'];
                $this->mLinks = $jsonData['Links'];
                $this->mLinksSpecial = $jsonData['LinksSpecial'];
                $this->mTemplates = $jsonData['Templates'];
                $this->mTemplateIds = $jsonData['TemplateIds'];
                $this->mImages = $jsonData['Images'];
                $this->mFileSearchOptions = $jsonData['FileSearchOptions'];
                $this->mExternalLinks = $jsonData['ExternalLinks'];
                $this->mInterwikiLinks = $jsonData['InterwikiLinks'];
                $this->mNewSection = $jsonData['NewSection'];
                $this->mHideNewSection = $jsonData['HideNewSection'];
                $this->mNoGallery = $jsonData['NoGallery'];
                $this->mHeadItems = $jsonData['HeadItems'];
                $this->mModuleSet = array_fill_keys( $jsonData['Modules'], true );
                $this->mModuleStyleSet = array_fill_keys( $jsonData['ModuleStyles'], true );
                $this->mJsConfigVars = $jsonData['JsConfigVars'];
                $this->mWarnings = $jsonData['Warnings'];
                $this->mFlags = $jsonData['Flags'];
                if (
                        $jsonData['Sections'] !== [] ||
                        // backward-compatibility: distinguish "no sections" from
                        // "sections not set" (Will be unnecessary after T327439.)
                        $this->getOutputFlag( 'mw:toc-set' )
                ) {
                        $this->setSections( $jsonData['Sections'] );
                        unset( $this->mFlags['mw:toc-set'] );
                        if ( isset( $jsonData['TOCExtensionData'] ) ) {
                                $tocData = $this->getTOCData(); // created by setSections() above
                                foreach ( $jsonData['TOCExtensionData'] as $key => $value ) {
                                        $tocData->setExtensionData( $key, $value );
                                }
                        }
                }
                $this->mProperties = self::detectAndDecodeBinary( $jsonData['Properties'] );
                $this->mTimestamp = $jsonData['Timestamp'];
                $this->mEnableOOUI = $jsonData['EnableOOUI'];
                $this->setIndexPolicy( $jsonData['IndexPolicy'] );
                $this->mExtensionData = $jsonData['ExtensionData'] ?? [];
                $this->mLimitReportData = $jsonData['LimitReportData'];
                $this->mLimitReportJSData = $jsonData['LimitReportJSData'];
                $this->mCacheMessage = $jsonData['CacheMessage'] ?? '';
                $this->mParseStartTime = []; // invalid after reloading
                $this->mTimeProfile = $jsonData['TimeProfile'] ?? [];
                $this->mPreventClickjacking = $jsonData['PreventClickjacking'];
                $this->mExtraScriptSrcs = $jsonData['ExtraScriptSrcs'];
                $this->mExtraDefaultSrcs = $jsonData['ExtraDefaultSrcs'];
                $this->mExtraStyleSrcs = $jsonData['ExtraStyleSrcs'];
                $this->mSpeculativeRevId = $jsonData['SpeculativeRevId'];
                $this->speculativePageIdUsed = $jsonData['SpeculativePageIdUsed'];
                $this->revisionTimestampUsed = $jsonData['RevisionTimestampUsed'];
                $this->revisionUsedSha1Base36 = $jsonData['RevisionUsedSha1Base36'];
                $this->mWrapperDivClasses = $jsonData['WrapperDivClasses'];
                $this->mMaxAdaptiveExpiry = $jsonData['MaxAdaptiveExpiry'] ?? INF;
        }

        /**
         * Finds any non-utf8 strings in the given array and replaces them with
         * an associative array that wraps a base64 encoded version of the data.
         * Inverse of detectAndDecodeBinary().
         *
         * @param array $properties
         *
         * @return array
         */
        private static function detectAndEncodeBinary( array $properties ) {
                foreach ( $properties as $key => $value ) {
                        if ( is_string( $value ) ) {
                                if ( !mb_detect_encoding( $value, 'UTF-8', true ) ) {
                                        $properties[$key] = [
                                                // T313818: This key name conflicts with JsonCodec
                                                '_type_' => 'string',
                                                '_encoding_' => 'base64',
                                                '_data_' => base64_encode( $value ),
                                        ];
                                }
                        }
                }

                return $properties;
        }

        /**
         * Finds any associative arrays that represent encoded binary strings, and
         * replaces them with the decoded binary data.
         *
         * @param array $properties
         *
         * @return array
         */
        private static function detectAndDecodeBinary( array $properties ) {
                foreach ( $properties as $key => $value ) {
                        if ( is_array( $value ) && isset( $value['_encoding_'] ) ) {
                                if ( $value['_encoding_'] === 'base64' ) {
                                        $properties[$key] = base64_decode( $value['_data_'] );
                                }
                        }
                }

                return $properties;
        }

        public function __wakeup() {
                $oldAliases = [
                        // This was the pre-namespace name of the class, which is still
                        // used in pre-1.42 serialized objects.
                        'ParserOutput',
                ];
                // Backwards compatibility, pre 1.36
                $priorAccessedOptions = $this->getGhostFieldValue( 'mAccessedOptions', ...$oldAliases );
                if ( $priorAccessedOptions ) {
                        $this->mParseUsedOptions = $priorAccessedOptions;
                }
                // Backwards compatibility, pre 1.39
                $priorIndexPolicy = $this->getGhostFieldValue( 'mIndexPolicy', ...$oldAliases );
                if ( $priorIndexPolicy ) {
                        $this->setIndexPolicy( $priorIndexPolicy );
                }
                // Backwards compatibility, pre 1.40
                $mSections = $this->getGhostFieldValue( 'mSections', ...$oldAliases );
                if ( $mSections !== null && $mSections !== [] ) {
                        $this->setSections( $mSections );
                }
                // Backwards compatibility, pre 1.42
                $mModules = $this->getGhostFieldValue( 'mModules', ...$oldAliases );
                if ( $mModules !== null && $mModules !== [] ) {
                        $this->addModules( $mModules );
                }
                // Backwards compatibility, pre 1.42
                $mModuleStyles = $this->getGhostFieldValue( 'mModuleStyles', ...$oldAliases );
                if ( $mModuleStyles !== null && $mModuleStyles !== [] ) {
                        $this->addModuleStyles( $mModuleStyles );
                }
                // Backwards compatibility, pre 1.42
                $mText = $this->getGhostFieldValue( 'mText', ...$oldAliases );
                if ( $mText !== null ) {
                        $this->setRawText( $mText );
                }
                // Backwards compatibility, pre 1.42
                $ll = $this->getGhostFieldValue( 'mLanguageLinks', ...$oldAliases );
                if ( $ll !== null && $ll !== [] ) {
                        foreach ( $ll as $l ) {
                                $this->addLanguageLink( $l );
                        }
                }
                // Backward compatibility with private fields, pre 1.42
                $oldPrivateFields = [
                        'mRawText',
                        'mCategories',
                        'mIndicators',
                        'mTitleText',
                        'mLinks',
                        'mLinksSpecial',
                        'mTemplates',
                        'mTemplateIds',
                        'mImages',
                        'mFileSearchOptions',
                        'mExternalLinks',
                        'mInterwikiLinks',
                        'mNewSection',
                        'mHideNewSection',
                        'mNoGallery',
                        'mHeadItems',
                        'mModuleSet',
                        'mModuleStyleSet',
                        'mJsConfigVars',
                        'mWarnings',
                        'mWarningMsgs',
                        'mTOCData',
                        'mProperties',
                        'mTimestamp',
                        'mEnableOOUI',
                        'mIndexSet',
                        'mNoIndexSet',
                        'mExtensionData',
                        'mLimitReportData',
                        'mLimitReportJSData',
                        'mCacheMessage',
                        'mParseStartTime',
                        'mTimeProfile',
                        'mPreventClickjacking',
                        'mExtraScriptSrcs',
                        'mExtraDefaultSrcs',
                        'mExtraStyleSrcs',
                        'mFlags',
                        'mSpeculativeRevId',
                        'speculativePageIdUsed',
                        'revisionTimestampUsed',
                        'revisionUsedSha1Base36',
                        'mWrapperDivClasses',
                        'mMaxAdaptiveExpiry',
                ];
                foreach ( $oldPrivateFields as $f ) {
                        $this->restoreAliasedGhostField( $f, ...$oldAliases );
                }
                $this->clearParseStartTime();
        }

        public function __clone() {
                // It seems that very little of this object needs to be explicitly deep-cloned
                // while keeping copies reasonably separated.
                // Most of the non-scalar properties of this object are either
                // - (potentially multi-nested) arrays of scalars (which get deep-cloned), or
                // - arrays that may contain arbitrary elements (which don't necessarily get
                //   deep-cloned), but for which no particular care elsewhere is given to
                //   copying their references around (e.g. mJsConfigVars).
                // Hence, we are not going out of our way to ensure that the references to innermost
                // objects that may appear in a ParserOutput are unique. If that becomes the
                // expectation at any point, this method will require updating as well.
                // The exception is TOCData (which is an object), which we clone explicitly.
                if ( $this->mTOCData ) {
                        $this->mTOCData = clone $this->mTOCData;
                }
        }

        /**
         * Returns the content holder text of the ParserOutput.
         * This will eventually be replaced by something like getContentHolder()->getText() when we have a
         * ContentHolder/HtmlHolder class.
         * @internal
         * @unstable
         * @return string
         */
        public function getContentHolderText(): string {
                return $this->getRawText();
        }

        /**
         * Sets the content holder text of the ParserOutput.
         * This will eventually be replaced by something like getContentHolder()->setText() when we have a
         * ContentHolder/HtmlHolder class.
         * @internal
         * @unstable
         */
        public function setContentHolderText( string $s ): void {
                $this->setRawText( $s );
        }

        public function __get( $name ) {
                if ( property_exists( get_called_class(), $name ) ) {
                        // Direct access to a public property, deprecated.
                        wfDeprecatedMsg( "ParserOutput::{$name} public read access deprecated", '1.38' );
                        return $this->$name;
                } elseif ( property_exists( $this, $name ) ) {
                        // Dynamic property access, deprecated.
                        wfDeprecatedMsg( "ParserOutput::{$name} dynamic property read access deprecated", '1.38' );
                        return $this->$name;
                } else {
                        trigger_error( "Inaccessible property via __get(): $name" );
                        return null;
                }
        }

        public function __set( $name, $value ) {
                if ( property_exists( get_called_class(), $name ) ) {
                        // Direct access to a public property, deprecated.
                        wfDeprecatedMsg( "ParserOutput::$name public write access deprecated", '1.38' );
                        $this->$name = $value;
                } else {
                        // Dynamic property access, deprecated.
                        wfDeprecatedMsg( "ParserOutput::$name dynamic property write access deprecated", '1.38' );
                        $this->$name = $value;
                }
        }
}

/** @deprecated class alias since 1.42 */
class_alias( ParserOutput::class, 'ParserOutput' );