<?php
/**
 * Parser functions provided by MediaWiki core
 *
 * 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
 * @ingroup Parser
 */

use MediaWiki\Category\Category;
use MediaWiki\Config\ServiceOptions;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Parser\MagicWordFactory;
use MediaWiki\Parser\ParserOutputFlags;
use MediaWiki\Parser\Sanitizer;
use MediaWiki\Revision\RevisionAccessException;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\SiteStats\SiteStats;
use MediaWiki\SpecialPage\SpecialPage;
use MediaWiki\Title\Title;
use MediaWiki\User\User;
use Wikimedia\RemexHtml\Tokenizer\Attributes;
use Wikimedia\RemexHtml\Tokenizer\PlainAttributes;

/**
 * Various core parser functions, registered in every Parser
 * @ingroup Parser
 */
class CoreParserFunctions {
	/** @var int Assume that no output will later be saved this many seconds after parsing */
	private const MAX_TTS = 900;

	/**
	 * @internal
	 */
	public const REGISTER_OPTIONS = [
		// See documentation for the corresponding config options
		MainConfigNames::AllowDisplayTitle,
		MainConfigNames::AllowSlowParserFunctions,
	];

	/**
	 * @param Parser $parser
	 * @param ServiceOptions $options
	 *
	 * @return void
	 * @internal
	 */
	public static function register( Parser $parser, ServiceOptions $options ) {
		$options->assertRequiredOptions( self::REGISTER_OPTIONS );
		$allowDisplayTitle = $options->get( MainConfigNames::AllowDisplayTitle );
		$allowSlowParserFunctions = $options->get( MainConfigNames::AllowSlowParserFunctions );

		# Syntax for arguments (see Parser::setFunctionHook):
		#  "name for lookup in localized magic words array",
		#  function callback,
		#  optional Parser::SFH_NO_HASH to omit the hash from calls (e.g. {{int:...}}
		#    instead of {{#int:...}})
		$noHashFunctions = [
			'ns', 'nse', 'urlencode', 'lcfirst', 'ucfirst', 'lc', 'uc',
			'localurl', 'localurle', 'fullurl', 'fullurle', 'canonicalurl',
			'canonicalurle', 'formatnum', 'grammar', 'gender', 'plural', 'bidi',
			'numberingroup', 'language',
			'padleft', 'padright', 'anchorencode', 'defaultsort', 'filepath',
			'pagesincategory', 'pagesize', 'protectionlevel', 'protectionexpiry',
			# The following are the "parser function" forms of magic
			# variables defined in CoreMagicVariables.  The no-args form will
			# go through the magic variable code path (and be cached); the
			# presence of arguments will cause the parser function form to
			# be invoked. (Note that the actual implementation will pass
			# a Parser object as first argument, in addition to the
			# parser function parameters.)

			# For this group, the first parameter to the parser function is
			# "page title", and the no-args form (and the magic variable)
			# defaults to "current page title".
			'pagename', 'pagenamee',
			'fullpagename', 'fullpagenamee',
			'subpagename', 'subpagenamee',
			'rootpagename', 'rootpagenamee',
			'basepagename', 'basepagenamee',
			'talkpagename', 'talkpagenamee',
			'subjectpagename', 'subjectpagenamee',
			'pageid', 'revisionid', 'revisionday',
			'revisionday2', 'revisionmonth', 'revisionmonth1', 'revisionyear',
			'revisiontimestamp',
			'revisionuser',
			'cascadingsources',
			'namespace', 'namespacee', 'namespacenumber', 'talkspace', 'talkspacee',
			'subjectspace', 'subjectspacee',

			# More parser functions corresponding to CoreMagicVariables.
			# For this group, the first parameter to the parser function is
			# "raw" (uses the 'raw' format if present) and the no-args form
			# (and the magic variable) defaults to 'not raw'.
			'numberofarticles', 'numberoffiles',
			'numberofusers',
			'numberofactiveusers',
			'numberofpages',
			'numberofadmins',
			'numberofedits',
		];
		foreach ( $noHashFunctions as $func ) {
			$parser->setFunctionHook( $func, [ __CLASS__, $func ], Parser::SFH_NO_HASH );
		}

		$parser->setFunctionHook( 'int', [ __CLASS__, 'intFunction' ], Parser::SFH_NO_HASH );
		$parser->setFunctionHook( 'special', [ __CLASS__, 'special' ] );
		$parser->setFunctionHook( 'speciale', [ __CLASS__, 'speciale' ] );
		$parser->setFunctionHook( 'tag', [ __CLASS__, 'tagObj' ], Parser::SFH_OBJECT_ARGS );
		$parser->setFunctionHook( 'formatdate', [ __CLASS__, 'formatDate' ] );

		if ( $allowDisplayTitle ) {
			$parser->setFunctionHook(
				'displaytitle',
				[ __CLASS__, 'displaytitle' ],
				Parser::SFH_NO_HASH
			);
		}
		if ( $allowSlowParserFunctions ) {
			$parser->setFunctionHook(
				'pagesinnamespace',
				[ __CLASS__, 'pagesinnamespace' ],
				Parser::SFH_NO_HASH
			);
		}
	}

	/**
	 * @param Parser $parser
	 * @param string $part1 Message key
	 * @param mixed ...$params To pass to wfMessage()
	 * @return array
	 */
	public static function intFunction( $parser, $part1 = '', ...$params ) {
		if ( strval( $part1 ) !== '' ) {
			$message = wfMessage( $part1, $params )
				->inLanguage( $parser->getOptions()->getUserLangObj() );
			return [ $message->plain(), 'noparse' => false ];
		} else {
			return [ 'found' => false ];
		}
	}

	/**
	 * @param Parser $parser
	 * @param string $date
	 * @param string|null $defaultPref
	 *
	 * @return string
	 */
	public static function formatDate( $parser, $date, $defaultPref = null ) {
		$lang = $parser->getTargetLanguage();
		$df = MediaWikiServices::getInstance()->getDateFormatterFactory()->get( $lang );

		$date = trim( $date );

		$pref = $parser->getOptions()->getDateFormat();

		// Specify a different default date format other than the normal default
		// if the user has 'default' for their setting
		if ( $pref == 'default' && $defaultPref ) {
			$pref = $defaultPref;
		}

		$date = $df->reformat( $pref, $date, [ 'match-whole' ] );
		return $date;
	}

	public static function ns( $parser, $part1 = '' ) {
		if ( intval( $part1 ) || $part1 == "0" ) {
			$index = intval( $part1 );
		} else {
			$index = $parser->getContentLanguage()->getNsIndex( str_replace( ' ', '_', $part1 ) );
		}
		if ( $index !== false ) {
			return $parser->getContentLanguage()->getFormattedNsText( $index );
		} else {
			return [ 'found' => false ];
		}
	}

	public static function nse( $parser, $part1 = '' ) {
		$ret = self::ns( $parser, $part1 );
		if ( is_string( $ret ) ) {
			$ret = wfUrlencode( str_replace( ' ', '_', $ret ) );
		}
		return $ret;
	}

	/**
	 * urlencodes a string according to one of three patterns: (T24474)
	 *
	 * By default (for HTTP "query" strings), spaces are encoded as '+'.
	 * Or to encode a value for the HTTP "path", spaces are encoded as '%20'.
	 * For links to "wiki"s, or similar software, spaces are encoded as '_',
	 *
	 * @param Parser $parser
	 * @param string $s The text to encode.
	 * @param string|null $arg (optional): The type of encoding.
	 * @return string
	 */
	public static function urlencode( $parser, $s = '', $arg = null ) {
		static $magicWords = null;
		if ( $magicWords === null ) {
			$magicWords =
				$parser->getMagicWordFactory()->newArray( [ 'url_path', 'url_query', 'url_wiki' ] );
		}
		switch ( $magicWords->matchStartToEnd( $arg ?? '' ) ) {
			// Encode as though it's a wiki page, '_' for ' '.
			case 'url_wiki':
				$func = 'wfUrlencode';
				$s = str_replace( ' ', '_', $s );
				break;

			// Encode for an HTTP Path, '%20' for ' '.
			case 'url_path':
				$func = 'rawurlencode';
				break;

			// Encode for HTTP query, '+' for ' '.
			case 'url_query':
			default:
				$func = 'urlencode';
		}
		// See T105242, where the choice to kill markers and various
		// other options were discussed.
		return $func( $parser->killMarkers( $s ) );
	}

	public static function lcfirst( $parser, $s = '' ) {
		return $parser->getContentLanguage()->lcfirst( $s );
	}

	public static function ucfirst( $parser, $s = '' ) {
		return $parser->getContentLanguage()->ucfirst( $s );
	}

	/**
	 * @param Parser $parser
	 * @param string $s
	 * @return string
	 */
	public static function lc( $parser, $s = '' ) {
		return $parser->markerSkipCallback( $s, [ $parser->getContentLanguage(), 'lc' ] );
	}

	/**
	 * @param Parser $parser
	 * @param string $s
	 * @return string
	 */
	public static function uc( $parser, $s = '' ) {
		return $parser->markerSkipCallback( $s, [ $parser->getContentLanguage(), 'uc' ] );
	}

	public static function localurl( $parser, $s = '', $arg = null ) {
		return self::urlFunction( 'getLocalURL', $s, $arg );
	}

	public static function localurle( $parser, $s = '', $arg = null ) {
		$temp = self::urlFunction( 'getLocalURL', $s, $arg );
		if ( !is_string( $temp ) ) {
			return $temp;
		} else {
			return htmlspecialchars( $temp, ENT_COMPAT );
		}
	}

	public static function fullurl( $parser, $s = '', $arg = null ) {
		return self::urlFunction( 'getFullURL', $s, $arg );
	}

	public static function fullurle( $parser, $s = '', $arg = null ) {
		$temp = self::urlFunction( 'getFullURL', $s, $arg );
		if ( !is_string( $temp ) ) {
			return $temp;
		} else {
			return htmlspecialchars( $temp, ENT_COMPAT );
		}
	}

	public static function canonicalurl( $parser, $s = '', $arg = null ) {
		return self::urlFunction( 'getCanonicalURL', $s, $arg );
	}

	public static function canonicalurle( $parser, $s = '', $arg = null ) {
		$temp = self::urlFunction( 'getCanonicalURL', $s, $arg );
		if ( !is_string( $temp ) ) {
			return $temp;
		} else {
			return htmlspecialchars( $temp, ENT_COMPAT );
		}
	}

	public static function urlFunction( $func, $s = '', $arg = null ) {
		# Due to order of execution of a lot of bits, the values might be encoded
		# before arriving here; if that's true, then the title can't be created
		# and the variable will fail. If we can't get a decent title from the first
		# attempt, url-decode and try for a second.
		$title = Title::newFromText( $s ) ?? Title::newFromURL( urldecode( $s ) );
		if ( $title !== null ) {
			# Convert NS_MEDIA -> NS_FILE
			if ( $title->inNamespace( NS_MEDIA ) ) {
				$title = Title::makeTitle( NS_FILE, $title->getDBkey() );
			}
			if ( $arg !== null ) {
				$text = $title->$func( $arg );
			} else {
				$text = $title->$func();
			}
			return $text;
		} else {
			return [ 'found' => false ];
		}
	}

	/**
	 * @param Parser $parser
	 * @param string $num
	 * @param string|null $arg
	 * @return string
	 */
	public static function formatnum( $parser, $num = '', $arg = null ) {
		if ( self::matchAgainstMagicword( $parser->getMagicWordFactory(), 'rawsuffix', $arg ) ) {
			$func = [ $parser->getTargetLanguage(), 'parseFormattedNumber' ];
		} elseif (
			self::matchAgainstMagicword( $parser->getMagicWordFactory(), 'nocommafysuffix', $arg )
		) {
			$func = [ $parser->getTargetLanguage(), 'formatNumNoSeparators' ];
			$func = self::getLegacyFormatNum( $parser, $func );
		} else {
			$func = [ $parser->getTargetLanguage(), 'formatNum' ];
			$func = self::getLegacyFormatNum( $parser, $func );
		}
		return $parser->markerSkipCallback( $num, $func );
	}

	/**
	 * @param Parser $parser
	 * @param callable $callback
	 *
	 * @return callable
	 */
	private static function getLegacyFormatNum( $parser, $callback ) {
		// For historic reasons, the formatNum parser function will
		// take arguments which are not actually formatted numbers,
		// which then trigger deprecation warnings in Language::formatNum*.
		// Instead emit a tracking category instead to allow linting.
		return static function ( $number ) use ( $parser, $callback ) {
			$validNumberRe = '(-(?=[\d\.]))?(\d+|(?=\.\d))(\.\d*)?([Ee][-+]?\d+)?';
			if (
				!is_numeric( $number ) &&
				$number !== (string)NAN &&
				$number !== (string)INF &&
				$number !== (string)-INF
			) {
				$parser->addTrackingCategory( 'nonnumeric-formatnum' );
				// Don't split on NAN/INF in the legacy case since they are
				// likely to be found embedded inside non-numeric text.
				return preg_replace_callback( "/{$validNumberRe}/", static function ( $m ) use ( $callback ) {
					return call_user_func( $callback, $m[0] );
				}, $number );
			}
			return call_user_func( $callback, $number );
		};
	}

	/**
	 * @param Parser $parser
	 * @param string $case
	 * @param string $word
	 * @return string
	 */
	public static function grammar( $parser, $case = '', $word = '' ) {
		$word = $parser->killMarkers( $word );
		return $parser->getTargetLanguage()->convertGrammar( $word, $case );
	}

	/**
	 * @param Parser $parser
	 * @param string $username
	 * @param string ...$forms What to output for each gender
	 * @return string
	 */
	public static function gender( $parser, $username, ...$forms ) {
		// Some shortcuts to avoid loading user data unnecessarily
		if ( count( $forms ) === 0 ) {
			return '';
		} elseif ( count( $forms ) === 1 ) {
			return $forms[0];
		}

		$username = trim( $username );

		$userOptionsLookup = MediaWikiServices::getInstance()->getUserOptionsLookup();
		$gender = $userOptionsLookup->getDefaultOption( 'gender' );

		// allow prefix and normalize (e.g. "&#42;foo" -> "*foo" ).
		$title = Title::newFromText( $username, NS_USER );

		if ( $title && $title->inNamespace( NS_USER ) ) {
			$username = $title->getText();
		}

		// check parameter, or use the ParserOptions if in interface message
		$user = User::newFromName( $username );
		$genderCache = MediaWikiServices::getInstance()->getGenderCache();
		if ( $user ) {
			$gender = $genderCache->getGenderOf( $user, __METHOD__ );
		} elseif ( $username === '' && $parser->getOptions()->getInterfaceMessage() ) {
			$gender = $genderCache->getGenderOf( $parser->getOptions()->getUserIdentity(), __METHOD__ );
		}
		$ret = $parser->getTargetLanguage()->gender( $gender, $forms );
		return $ret;
	}

	/**
	 * @param Parser $parser
	 * @param string $text
	 * @param string ...$forms What to output for each number (singular, dual, plural, etc.)
	 * @return string
	 */
	public static function plural( $parser, $text = '', ...$forms ) {
		$text = $parser->getTargetLanguage()->parseFormattedNumber( $text );
		settype( $text, ctype_digit( $text ) ? 'int' : 'float' );
		// @phan-suppress-next-line PhanTypeMismatchArgument Phan does not handle settype
		return $parser->getTargetLanguage()->convertPlural( $text, $forms );
	}

	/**
	 * @param Parser $parser
	 * @param string $text
	 * @return string
	 */
	public static function bidi( $parser, $text = '' ) {
		return $parser->getTargetLanguage()->embedBidi( $text );
	}

	/**
	 * Override the title of the page when viewed, provided we've been given a
	 * title which will normalise to the canonical title
	 *
	 * @param Parser $parser Parent parser
	 * @param string $text Desired title text
	 * @param string $uarg
	 * @return string
	 */
	public static function displaytitle( $parser, $text = '', $uarg = '' ) {
		$restrictDisplayTitle = MediaWikiServices::getInstance()->getMainConfig()
			->get( MainConfigNames::RestrictDisplayTitle );

		static $magicWords = null;
		if ( $magicWords === null ) {
			$magicWords = $parser->getMagicWordFactory()->newArray(
				[ 'displaytitle_noerror', 'displaytitle_noreplace' ] );
		}
		$arg = $magicWords->matchStartToEnd( $uarg );

		// parse a limited subset of wiki markup (just the single quote items)
		$text = $parser->doQuotes( $text );

		// remove stripped text (e.g. the UNIQ-QINU stuff) that was generated by tag extensions/whatever
		$text = $parser->killMarkers( $text );

		// See T28547 for rationale for this processing.
		// list of disallowed tags for DISPLAYTITLE
		// these will be escaped even though they are allowed in normal wiki text
		$bad = [ 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'div', 'blockquote', 'ol', 'ul', 'li', 'hr',
			'table', 'tr', 'th', 'td', 'dl', 'dd', 'caption', 'p', 'ruby', 'rb', 'rt', 'rtc', 'rp', 'br' ];

		// disallow some styles that could be used to bypass $wgRestrictDisplayTitle
		if ( $restrictDisplayTitle ) {
			// This code is tested with the cases marked T28547 in
			// parserTests.txt
			$htmlTagsCallback = static function ( Attributes $attr ): Attributes {
				$decoded = $attr->getValues();

				if ( isset( $decoded['style'] ) ) {
					// this is called later anyway, but we need it right now for the regexes below to be safe
					// calling it twice doesn't hurt
					$decoded['style'] = Sanitizer::checkCss( $decoded['style'] );

					if ( preg_match( '/(display|user-select|visibility)\s*:/i', $decoded['style'] ) ) {
						$decoded['style'] = '/* attempt to bypass $wgRestrictDisplayTitle */';
					}
				}

				return new PlainAttributes( $decoded );
			};
		} else {
			$htmlTagsCallback = null;
		}

		// only requested titles that normalize to the actual title are allowed through
		// if $wgRestrictDisplayTitle is true (it is by default)
		// mimic the escaping process that occurs in OutputPage::setPageTitle
		$text = Sanitizer::removeSomeTags( $text, [
			'attrCallback' => $htmlTagsCallback,
			'removeTags' => $bad,
		] );
		$title = Title::newFromText( Sanitizer::stripAllTags( $text ) );
		// Decode entities in $text the same way that Title::newFromText does
		$filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );

		if ( !$restrictDisplayTitle ||
			( $title instanceof Title
			&& !$title->hasFragment()
			&& $title->equals( $parser->getTitle() ) )
		) {
			$old = $parser->getOutput()->getPageProperty( 'displaytitle' );
			if ( $old === null || $arg !== 'displaytitle_noreplace' ) {
				$parser->getOutput()->setDisplayTitle( $text );
			}
			if ( $old !== null && $old !== $text && !$arg ) {

				$converter = $parser->getTargetLanguageConverter();
				return '<span class="error">' .
					$parser->msg( 'duplicate-displaytitle',
						// Message should be parsed, but these params should only be escaped.
						$converter->markNoConversion( wfEscapeWikiText( $old ) ),
						$converter->markNoConversion( wfEscapeWikiText( $filteredText ) )
					)->text() .
					'</span>';
			} else {
				return '';
			}
		} else {
			$parser->getOutput()->addWarningMsg(
				'restricted-displaytitle',
				// Message should be parsed, but this param should only be escaped.
				Message::plaintextParam( $filteredText )
			);
			$parser->addTrackingCategory( 'restricted-displaytitle-ignored' );
		}
	}

	/**
	 * Matches the given value against the value of given magic word
	 *
	 * @param MagicWordFactory $magicWordFactory A factory to get the word from, e.g., from
	 *   $parser->getMagicWordFactory()
	 * @param string $magicword Magic word key
	 * @param string $value Value to match
	 * @return bool True on successful match
	 */
	private static function matchAgainstMagicword(
		MagicWordFactory $magicWordFactory, $magicword, $value
	) {
		$value = trim( strval( $value ) );
		if ( $value === '' ) {
			return false;
		}
		$mwObject = $magicWordFactory->get( $magicword );
		return $mwObject->matchStartToEnd( $value );
	}

	/**
	 * Formats a number according to a language.
	 *
	 * @param int|float $num
	 * @param ?string $raw
	 * @param Language $language
	 * @param MagicWordFactory|null $magicWordFactory To evaluate $raw
	 * @return string
	 */
	public static function formatRaw(
		$num, $raw, $language, MagicWordFactory $magicWordFactory = null
	) {
		if ( $raw !== null && $raw !== '' ) {
			if ( !$magicWordFactory ) {
				$magicWordFactory = MediaWikiServices::getInstance()->getMagicWordFactory();
			}
			if ( self::matchAgainstMagicword( $magicWordFactory, 'rawsuffix', $raw ) ) {
				return (string)$num;
			}
		}
		return $language->formatNum( $num );
	}

	public static function numberofpages( $parser, $raw = null ) {
		return self::formatRaw( SiteStats::pages(), $raw, $parser->getTargetLanguage() );
	}

	public static function numberofusers( $parser, $raw = null ) {
		return self::formatRaw( SiteStats::users(), $raw, $parser->getTargetLanguage() );
	}

	public static function numberofactiveusers( $parser, $raw = null ) {
		return self::formatRaw( SiteStats::activeUsers(), $raw, $parser->getTargetLanguage() );
	}

	public static function numberofarticles( $parser, $raw = null ) {
		return self::formatRaw( SiteStats::articles(), $raw, $parser->getTargetLanguage() );
	}

	public static function numberoffiles( $parser, $raw = null ) {
		return self::formatRaw( SiteStats::images(), $raw, $parser->getTargetLanguage() );
	}

	public static function numberofadmins( $parser, $raw = null ) {
		return self::formatRaw(
			SiteStats::numberingroup( 'sysop' ),
			$raw,
			$parser->getTargetLanguage()
		);
	}

	public static function numberofedits( $parser, $raw = null ) {
		return self::formatRaw( SiteStats::edits(), $raw, $parser->getTargetLanguage() );
	}

	public static function pagesinnamespace( $parser, $namespace = 0, $raw = null ) {
		return self::formatRaw(
			SiteStats::pagesInNs( intval( $namespace ) ),
			$raw,
			$parser->getTargetLanguage()
		);
	}

	public static function numberingroup( $parser, $name = '', $raw = null ) {
		return self::formatRaw(
			SiteStats::numberingroup( strtolower( $name ) ),
			$raw,
			$parser->getTargetLanguage()
		);
	}

	/**
	 * Helper function for preprocessing an optional argument which represents
	 * a title.
	 * @param Parser $parser
	 * @param string|null $t if null, returns the Parser's Title
	 *   for consistency with magic variable forms
	 * @return ?Title
	 */
	private static function makeTitle( Parser $parser, ?string $t ) {
		if ( $t === null ) {
			// For consistency with magic variable forms
			$title = $parser->getTitle();
		} else {
			$title = Title::newFromText( $t );
		}
		return $title;
	}

	/**
	 * Given a title, return the namespace name that would be given by the
	 * corresponding magic word
	 * @param Parser $parser
	 * @param string|null $title
	 * @return mixed|string
	 * @since 1.39
	 */
	public static function namespace( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return str_replace( '_', ' ', $t->getNsText() );
	}

	/**
	 * Given a title, return the namespace name that would be given by the
	 * corresponding magic word.
	 * @note This function corresponded to the `namespace` parser function
	 * and magic variable, but `namespace` was a reserved word before PHP 7.
	 * @param Parser $parser
	 * @param string|null $title
	 * @return mixed|string
	 * @deprecated Use CoreParserFunctions::namespace() instead.
	 */
	public static function mwnamespace( $parser, $title = null ) {
		wfDeprecated( __METHOD__, '1.39' );
		return self::namespace( $parser, $title );
	}

	public static function namespacee( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfUrlencode( $t->getNsText() );
	}

	public static function namespacenumber( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return (string)$t->getNamespace();
	}

	public static function talkspace( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null || !$t->canHaveTalkPage() ) {
			return '';
		}
		return str_replace( '_', ' ', $t->getTalkNsText() );
	}

	public static function talkspacee( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null || !$t->canHaveTalkPage() ) {
			return '';
		}
		return wfUrlencode( $t->getTalkNsText() );
	}

	public static function subjectspace( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return str_replace( '_', ' ', $t->getSubjectNsText() );
	}

	public static function subjectspacee( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfUrlencode( $t->getSubjectNsText() );
	}

	/**
	 * Functions to get and normalize pagenames, corresponding to the magic words
	 * of the same names
	 * @param Parser $parser
	 * @param string|null $title
	 * @return string
	 */
	public static function pagename( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfEscapeWikiText( $t->getText() );
	}

	public static function pagenamee( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfEscapeWikiText( $t->getPartialURL() );
	}

	public static function fullpagename( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfEscapeWikiText( $t->getPrefixedText() );
	}

	public static function fullpagenamee( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfEscapeWikiText( $t->getPrefixedURL() );
	}

	public static function subpagename( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfEscapeWikiText( $t->getSubpageText() );
	}

	public static function subpagenamee( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfEscapeWikiText( $t->getSubpageUrlForm() );
	}

	public static function rootpagename( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfEscapeWikiText( $t->getRootText() );
	}

	public static function rootpagenamee( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfEscapeWikiText( wfUrlencode( str_replace( ' ', '_', $t->getRootText() ) ) );
	}

	public static function basepagename( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfEscapeWikiText( $t->getBaseText() );
	}

	public static function basepagenamee( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfEscapeWikiText( wfUrlencode( str_replace( ' ', '_', $t->getBaseText() ) ) );
	}

	public static function talkpagename( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null || !$t->canHaveTalkPage() ) {
			return '';
		}
		return wfEscapeWikiText( $t->getTalkPage()->getPrefixedText() );
	}

	public static function talkpagenamee( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null || !$t->canHaveTalkPage() ) {
			return '';
		}
		return wfEscapeWikiText( $t->getTalkPage()->getPrefixedURL() );
	}

	public static function subjectpagename( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfEscapeWikiText( $t->getSubjectPage()->getPrefixedText() );
	}

	public static function subjectpagenamee( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return wfEscapeWikiText( $t->getSubjectPage()->getPrefixedURL() );
	}

	/**
	 * Return the number of pages, files or subcats in the given category,
	 * or 0 if it's nonexistent. This is an expensive parser function and
	 * can't be called too many times per page.
	 * @param Parser $parser
	 * @param string $name
	 * @param string $arg1
	 * @param string $arg2
	 * @return string
	 */
	public static function pagesincategory( $parser, $name = '', $arg1 = '', $arg2 = '' ) {
		static $magicWords = null;
		if ( $magicWords === null ) {
			$magicWords = $parser->getMagicWordFactory()->newArray( [
				'pagesincategory_all',
				'pagesincategory_pages',
				'pagesincategory_subcats',
				'pagesincategory_files'
			] );
		}
		static $cache = [];

		// split the given option to its variable
		if ( self::matchAgainstMagicword( $parser->getMagicWordFactory(), 'rawsuffix', $arg1 ) ) {
			// {{pagesincategory:|raw[|type]}}
			$raw = $arg1;
			$type = $magicWords->matchStartToEnd( $arg2 );
		} else {
			// {{pagesincategory:[|type[|raw]]}}
			$type = $magicWords->matchStartToEnd( $arg1 );
			$raw = $arg2;
		}
		if ( !$type ) { // backward compatibility
			$type = 'pagesincategory_all';
		}

		$title = Title::makeTitleSafe( NS_CATEGORY, $name );
		if ( !$title ) { # invalid title
			return self::formatRaw( 0, $raw, $parser->getTargetLanguage() );
		}
		$languageConverter = MediaWikiServices::getInstance()
			->getLanguageConverterFactory()
			->getLanguageConverter( $parser->getContentLanguage() );
		$languageConverter->findVariantLink( $name, $title, true );

		// Normalize name for cache
		$name = $title->getDBkey();

		if ( !isset( $cache[$name] ) ) {
			$category = Category::newFromTitle( $title );

			$allCount = $subcatCount = $fileCount = $pageCount = 0;
			if ( $parser->incrementExpensiveFunctionCount() ) {
				$allCount = $category->getMemberCount();
				$subcatCount = $category->getSubcatCount();
				$fileCount = $category->getFileCount();
				$pageCount = $category->getPageCount( Category::COUNT_CONTENT_PAGES );
			}
			$cache[$name]['pagesincategory_all'] = $allCount;
			$cache[$name]['pagesincategory_pages'] = $pageCount;
			$cache[$name]['pagesincategory_subcats'] = $subcatCount;
			$cache[$name]['pagesincategory_files'] = $fileCount;
		}

		$count = $cache[$name][$type];
		return self::formatRaw( $count, $raw, $parser->getTargetLanguage() );
	}

	/**
	 * Return the size of the given page, or 0 if it's nonexistent.  This is an
	 * expensive parser function and can't be called too many times per page.
	 *
	 * @param Parser $parser
	 * @param string $page Name of page to check (Default: empty string)
	 * @param string|null $raw Should number be human readable with commas or just number
	 * @return string
	 */
	public static function pagesize( $parser, $page = '', $raw = null ) {
		$title = Title::newFromText( $page );

		if ( !is_object( $title ) ) {
			return self::formatRaw( 0, $raw, $parser->getTargetLanguage() );
		}

		// fetch revision from cache/database and return the value
		$rev = self::getCachedRevisionObject( $parser, $title, ParserOutputFlags::VARY_REVISION_SHA1 );
		$length = $rev ? $rev->getSize() : 0;
		if ( $length === null ) {
			// We've had bugs where rev_len was not being recorded for empty pages, see T135414
			$length = 0;
		}
		return self::formatRaw( $length, $raw, $parser->getTargetLanguage() );
	}

	/**
	 * Returns the requested protection level for the current page. This
	 * is an expensive parser function and can't be called too many times
	 * per page, unless the protection levels/expiries for the given title
	 * have already been retrieved
	 *
	 * @param Parser $parser
	 * @param string $type
	 * @param string $title
	 *
	 * @return string
	 */
	public static function protectionlevel( $parser, $type = '', $title = '' ) {
		$titleObject = Title::newFromText( $title ) ?? $parser->getTitle();
		$restrictionStore = MediaWikiServices::getInstance()->getRestrictionStore();
		if ( $restrictionStore->areRestrictionsLoaded( $titleObject ) || $parser->incrementExpensiveFunctionCount() ) {
			$restrictions = $restrictionStore->getRestrictions( $titleObject, strtolower( $type ) );
			# RestrictionStore::getRestrictions returns an array, its possible it may have
			# multiple values in the future
			return implode( ',', $restrictions );
		}
		return '';
	}

	/**
	 * Returns the requested protection expiry for the current page. This
	 * is an expensive parser function and can't be called too many times
	 * per page, unless the protection levels/expiries for the given title
	 * have already been retrieved
	 *
	 * @param Parser $parser
	 * @param string $type
	 * @param string $title
	 *
	 * @return string
	 */
	public static function protectionexpiry( $parser, $type = '', $title = '' ) {
		$titleObject = Title::newFromText( $title ) ?? $parser->getTitle();
		$restrictionStore = MediaWikiServices::getInstance()->getRestrictionStore();
		if ( $restrictionStore->areRestrictionsLoaded( $titleObject ) || $parser->incrementExpensiveFunctionCount() ) {
			// getRestrictionExpiry() returns null on invalid type; trying to
			// match protectionlevel() function that returns empty string instead
			return $restrictionStore->getRestrictionExpiry( $titleObject, strtolower( $type ) ) ?? '';
		}
		return '';
	}

	/**
	 * Gives language names.
	 * @param Parser $parser
	 * @param string $code Language code (of which to get name)
	 * @param string $inLanguage Language code (in which to get name)
	 * @return string
	 */
	public static function language( $parser, $code = '', $inLanguage = '' ) {
		$code = strtolower( $code );
		$inLanguage = strtolower( $inLanguage );
		$lang = MediaWikiServices::getInstance()
			->getLanguageNameUtils()
			->getLanguageName( $code, $inLanguage );
		return $lang !== '' ? $lang : LanguageCode::bcp47( $code );
	}

	/**
	 * Unicode-safe str_pad with the restriction that $length is forced to be <= 500
	 * @param Parser $parser
	 * @param string $string
	 * @param string $length
	 * @param string $padding
	 * @param int $direction
	 * @return string
	 */
	public static function pad(
		$parser, $string, $length, $padding = '0', $direction = STR_PAD_RIGHT
	) {
		$padding = $parser->killMarkers( $padding );
		$lengthOfPadding = mb_strlen( $padding );
		if ( $lengthOfPadding == 0 ) {
			return $string;
		}

		# The remaining length to add counts down to 0 as padding is added
		$length = min( (int)$length, 500 ) - mb_strlen( $string );
		if ( $length <= 0 ) {
			// Nothing to add
			return $string;
		}

		# $finalPadding is just $padding repeated enough times so that
		# mb_strlen( $string ) + mb_strlen( $finalPadding ) == $length
		$finalPadding = '';
		while ( $length > 0 ) {
			# If $length < $lengthofPadding, truncate $padding so we get the
			# exact length desired.
			$finalPadding .= mb_substr( $padding, 0, $length );
			$length -= $lengthOfPadding;
		}

		if ( $direction == STR_PAD_LEFT ) {
			return $finalPadding . $string;
		} else {
			return $string . $finalPadding;
		}
	}

	public static function padleft( $parser, $string = '', $length = 0, $padding = '0' ) {
		return self::pad( $parser, $string, $length, $padding, STR_PAD_LEFT );
	}

	public static function padright( $parser, $string = '', $length = 0, $padding = '0' ) {
		return self::pad( $parser, $string, $length, $padding );
	}

	/**
	 * @param Parser $parser
	 * @param string $text
	 * @return string
	 */
	public static function anchorencode( $parser, $text ) {
		$text = $parser->killMarkers( $text );
		$section = (string)substr( $parser->guessSectionNameFromWikiText( $text ), 1 );
		return Sanitizer::safeEncodeAttribute( $section );
	}

	public static function special( $parser, $text ) {
		[ $page, $subpage ] = MediaWikiServices::getInstance()->getSpecialPageFactory()->
			resolveAlias( $text );
		if ( $page ) {
			$title = SpecialPage::getTitleFor( $page, $subpage );
			return $title->getPrefixedText();
		} else {
			// unknown special page, just use the given text as its title, if at all possible
			$title = Title::makeTitleSafe( NS_SPECIAL, $text );
			return $title ? $title->getPrefixedText() : self::special( $parser, 'Badtitle' );
		}
	}

	public static function speciale( $parser, $text ) {
		return wfUrlencode( str_replace( ' ', '_', self::special( $parser, $text ) ) );
	}

	/**
	 * @param Parser $parser
	 * @param string $text The sortkey to use
	 * @param string $uarg Either "noreplace" or "noerror" (in en)
	 *   both suppress errors, and noreplace does nothing if
	 *   a default sortkey already exists.
	 * @return string
	 */
	public static function defaultsort( $parser, $text, $uarg = '' ) {
		static $magicWords = null;
		if ( $magicWords === null ) {
			$magicWords = $parser->getMagicWordFactory()->newArray(
				[ 'defaultsort_noerror', 'defaultsort_noreplace' ] );
		}
		$arg = $magicWords->matchStartToEnd( $uarg );

		$text = trim( $text );
		if ( strlen( $text ) == 0 ) {
			return '';
		}
		$old = $parser->getOutput()->getPageProperty( 'defaultsort' );
		if ( $old === null || $arg !== 'defaultsort_noreplace' ) {
			$parser->getOutput()->setPageProperty( 'defaultsort', $text );
		}

		if ( $old === null || $old == $text || $arg ) {
			return '';
		} else {
			$converter = $parser->getTargetLanguageConverter();
			return '<span class="error">' .
				$parser->msg( 'duplicate-defaultsort',
					// Message should be parsed, but these params should only be escaped.
					$converter->markNoConversion( wfEscapeWikiText( $old ) ),
					$converter->markNoConversion( wfEscapeWikiText( $text ) )
				)->text() .
				'</span>';
		}
	}

	/**
	 * Usage {{filepath|300}}, {{filepath|nowiki}}, {{filepath|nowiki|300}}
	 * or {{filepath|300|nowiki}} or {{filepath|300px}}, {{filepath|200x300px}},
	 * {{filepath|nowiki|200x300px}}, {{filepath|200x300px|nowiki}}.
	 *
	 * @param Parser $parser
	 * @param string $name
	 * @param string $argA
	 * @param string $argB
	 * @return array|string
	 */
	public static function filepath( $parser, $name = '', $argA = '', $argB = '' ) {
		$file = MediaWikiServices::getInstance()->getRepoGroup()->findFile( $name );

		if ( $argA == 'nowiki' ) {
			// {{filepath: | option [| size] }}
			$isNowiki = true;
			$parsedWidthParam = Parser::parseWidthParam( $argB );
		} else {
			// {{filepath: [| size [|option]] }}
			$parsedWidthParam = Parser::parseWidthParam( $argA );
			$isNowiki = ( $argB == 'nowiki' );
		}

		if ( $file ) {
			$url = $file->getFullUrl();

			// If a size is requested...
			if ( count( $parsedWidthParam ) ) {
				$mto = $file->transform( $parsedWidthParam );
				// ... and we can
				if ( $mto && !$mto->isError() ) {
					// ... change the URL to point to a thumbnail.
					$url = wfExpandUrl( $mto->getUrl(), PROTO_RELATIVE );
				}
			}
			if ( $isNowiki ) {
				return [ $url, 'nowiki' => true ];
			}
			return $url;
		} else {
			return '';
		}
	}

	/**
	 * Parser function to extension tag adaptor
	 * @param Parser $parser
	 * @param PPFrame $frame
	 * @param PPNode[] $args
	 * @return string
	 */
	public static function tagObj( $parser, $frame, $args ) {
		if ( !count( $args ) ) {
			return '';
		}
		$tagName = strtolower( trim( $frame->expand( array_shift( $args ) ) ) );
		$processNowiki = $parser->tagNeedsNowikiStrippedInTagPF( $tagName ) ? PPFrame::PROCESS_NOWIKI : 0;

		if ( count( $args ) ) {
			$inner = $frame->expand( array_shift( $args ), $processNowiki );
		} else {
			$inner = null;
		}

		$attributes = [];
		foreach ( $args as $arg ) {
			$bits = $arg->splitArg();
			if ( strval( $bits['index'] ) === '' ) {
				$name = trim( $frame->expand( $bits['name'], PPFrame::STRIP_COMMENTS ) );
				$value = trim( $frame->expand( $bits['value'] ) );
				if ( preg_match( '/^(?:["\'](.+)["\']|""|\'\')$/s', $value, $m ) ) {
					$value = $m[1] ?? '';
				}
				$attributes[$name] = $value;
			}
		}

		$stripList = $parser->getStripList();
		if ( !in_array( $tagName, $stripList ) ) {
			// we can't handle this tag (at least not now), so just re-emit it as an ordinary tag
			$attrText = '';
			foreach ( $attributes as $name => $value ) {
				$attrText .= ' ' . htmlspecialchars( $name ) .
					'="' . htmlspecialchars( $value, ENT_COMPAT ) . '"';
			}
			if ( $inner === null ) {
				return "<$tagName$attrText/>";
			}
			return "<$tagName$attrText>$inner</$tagName>";
		}

		$params = [
			'name' => $tagName,
			'inner' => $inner,
			'attributes' => $attributes,
			'close' => "</$tagName>",
		];
		return $parser->extensionSubstitution( $params, $frame );
	}

	/**
	 * Fetched the current revision of the given title and return this.
	 * Will increment the expensive function count and
	 * add a template link to get the value refreshed on changes.
	 * For a given title, which is equal to the current parser title,
	 * the RevisionRecord object from the parser is used, when that is the current one
	 *
	 * @param Parser $parser
	 * @param Title $title
	 * @param string $vary ParserOutput vary-* flag
	 * @return RevisionRecord|null
	 * @since 1.23
	 */
	private static function getCachedRevisionObject( $parser, $title, $vary ) {
		if ( !$title ) {
			return null;
		}

		$revisionRecord = null;

		$isSelfReferential = $title->equals( $parser->getTitle() );
		if ( $isSelfReferential ) {
			// Revision is for the same title that is currently being parsed. Only use the last
			// saved revision, regardless of Parser::getRevisionId() or fake revision injection
			// callbacks against the current title.

			// FIXME (T318278): the above is the intention, but doesn't
			// describe the actual current behavior of this code, since
			// ->isCurrent() for the last saved revision will return
			// false so we're going to fall through and end up calling
			// ->getCurrentRevisionRecordOfTitle().
			$parserRevisionRecord = $parser->getRevisionRecordObject();
			if ( $parserRevisionRecord && $parserRevisionRecord->isCurrent() ) {
				$revisionRecord = $parserRevisionRecord;
			}
		}

		$parserOutput = $parser->getOutput();
		if ( !$revisionRecord ) {
			if (
				!$parser->isCurrentRevisionOfTitleCached( $title ) &&
				!$parser->incrementExpensiveFunctionCount()
			) {
				return null; // not allowed
			}
			// Get the current revision, ignoring Parser::getRevisionId() being null/old
			$revisionRecord = $parser->fetchCurrentRevisionRecordOfTitle( $title );
			if ( !$revisionRecord ) {
				// Convert `false` error return to `null`
				$revisionRecord = null;
			}
			// Register dependency in templatelinks
			$parserOutput->addTemplate(
				$title,
				$revisionRecord ? $revisionRecord->getPageId() : 0,
				$revisionRecord ? $revisionRecord->getId() : 0
			);
		}

		if ( $isSelfReferential ) {
			wfDebug( __METHOD__ . ": used current revision, setting $vary" );
			// Upon page save, the result of the parser function using this might change
			$parserOutput->setOutputFlag( $vary );
			if ( $vary === ParserOutputFlags::VARY_REVISION_SHA1 && $revisionRecord ) {
				try {
					$sha1 = $revisionRecord->getSha1();
				} catch ( RevisionAccessException $e ) {
					$sha1 = null;
				}
				$parserOutput->setRevisionUsedSha1Base36( $sha1 );
			}
		}

		return $revisionRecord;
	}

	/**
	 * Get the pageid of a specified page
	 * @param Parser $parser
	 * @param string|null $title Title to get the pageid from
	 * @return int|null|string
	 * @since 1.23
	 */
	public static function pageid( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( !$t ) {
			return '';
		} elseif ( !$t->canExist() || $t->isExternal() ) {
			return 0; // e.g. special page or interwiki link
		}

		$parserOutput = $parser->getOutput();

		if ( $t->equals( $parser->getTitle() ) ) {
			// Revision is for the same title that is currently being parsed.
			// Use the title from Parser in case a new page ID was injected into it.
			$parserOutput->setOutputFlag( ParserOutputFlags::VARY_PAGE_ID );
			$id = $parser->getTitle()->getArticleID();
			if ( $id ) {
				$parserOutput->setSpeculativePageIdUsed( $id );
			}

			return $id;
		}

		// Check the link cache for the title
		$linkCache = MediaWikiServices::getInstance()->getLinkCache();
		$pdbk = $t->getPrefixedDBkey();
		$id = $linkCache->getGoodLinkID( $pdbk );
		if ( $id != 0 || $linkCache->isBadLink( $pdbk ) ) {
			$parserOutput->addLink( $t, $id );

			return $id;
		}

		// We need to load it from the DB, so mark expensive
		if ( $parser->incrementExpensiveFunctionCount() ) {
			$id = $t->getArticleID();
			$parserOutput->addLink( $t, $id );

			return $id;
		}

		return null;
	}

	/**
	 * Get the id from the last revision of a specified page.
	 * @param Parser $parser
	 * @param string|null $title Title to get the id from
	 * @return int|null|string
	 * @since 1.23
	 */
	public static function revisionid( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}

		$services = MediaWikiServices::getInstance();
		if (
			$t->equals( $parser->getTitle() ) &&
			$services->getMainConfig()->get( MainConfigNames::MiserMode ) &&
			!$parser->getOptions()->getInterfaceMessage() &&
			// @TODO: disallow this word on all namespaces (T235957)
			$services->getNamespaceInfo()->isSubject( $t->getNamespace() )
		) {
			// Use a stub result instead of the actual revision ID in order to avoid
			// double parses on page save but still allow preview detection (T137900)
			if ( $parser->getRevisionId() || $parser->getOptions()->getSpeculativeRevId() ) {
				return '-';
			} else {
				$parser->getOutput()->setOutputFlag( ParserOutputFlags::VARY_REVISION_EXISTS );
				return '';
			}
		}
		// Fetch revision from cache/database and return the value.
		// Inform the edit saving system that getting the canonical output
		// after revision insertion requires a parse that used that exact
		// revision ID.
		if ( $t->equals( $parser->getTitle() ) && $title === null ) {
			// special handling for no-arg case: use speculative rev id
			// for current page.
			$parser->getOutput()->setOutputFlag( ParserOutputFlags::VARY_REVISION_ID );
			$id = $parser->getRevisionId();
			if ( $id === 0 ) {
				$rev = $parser->getRevisionRecordObject();
				if ( $rev ) {
					$id = $rev->getId();
				}
			}
			if ( !$id ) {
				$id = $parser->getOptions()->getSpeculativeRevId();
				if ( $id ) {
					$parser->getOutput()->setSpeculativeRevIdUsed( $id );
				}
			}
			return (string)$id;
		}
		$rev = self::getCachedRevisionObject( $parser, $t, ParserOutputFlags::VARY_REVISION_ID );
		return $rev ? $rev->getId() : '';
	}

	private static function getRevisionTimestampSubstring(
		Parser $parser,
		Title $title,
		int $start,
		int $len,
		int $mtts
	): string {
		// If fetching the revision timestamp of the current page, substitute the
		// speculative timestamp to be used when this revision is saved.  This
		// avoids having to invalidate the cache immediately by assuming the "last
		// saved revision" will in fact be this one.
		// Don't do this for interface messages (eg, edit notices) however; in that
		// case fall through and use the actual timestamp of the last saved revision.
		if ( $title->equals( $parser->getTitle() ) && !$parser->getOptions()->getInterfaceMessage() ) {
			// Get the timezone-adjusted timestamp to be used for this revision
			$resNow = substr( $parser->getRevisionTimestamp(), $start, $len );
			// Possibly set vary-revision if there is not yet an associated revision
			if ( !$parser->getRevisionRecordObject() ) {
				// Get the timezone-adjusted timestamp $mtts seconds in the future.
				// This future is relative to the current time and not that of the
				// parser options. The rendered timestamp can be compared to that
				// of the timestamp specified by the parser options.
				$resThen = substr(
					$parser->getContentLanguage()->userAdjust( wfTimestamp( TS_MW, time() + $mtts ), '' ),
					$start,
					$len
				);

				if ( $resNow !== $resThen ) {
					// Inform the edit saving system that getting the canonical output after
					// revision insertion requires a parse that used an actual revision timestamp
					$parser->getOutput()->setOutputFlag( ParserOutputFlags::VARY_REVISION_TIMESTAMP );
				}
			}

			return $resNow;
		} else {
			$rev = self::getCachedRevisionObject( $parser, $title, ParserOutputFlags::VARY_REVISION_TIMESTAMP );
			if ( !$rev ) {
				return '';
			}
			$resNow = substr(
				$parser->getContentLanguage()->userAdjust( $rev->getTimestamp(), '' ), $start, $len
			);
			return $resNow;
		}
	}

	/**
	 * Get the day from the last revision of a specified page.
	 * @param Parser $parser
	 * @param string|null $title Title to get the day from
	 * @return string
	 * @since 1.23
	 */
	public static function revisionday( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return strval( (int)self::getRevisionTimestampSubstring(
			$parser, $t, 6, 2, self::MAX_TTS
		) );
	}

	/**
	 * Get the day with leading zeros from the last revision of a specified page.
	 * @param Parser $parser
	 * @param string|null $title Title to get the day from
	 * @return string
	 * @since 1.23
	 */
	public static function revisionday2( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return self::getRevisionTimestampSubstring(
			$parser, $t, 6, 2, self::MAX_TTS
		);
	}

	/**
	 * Get the month with leading zeros from the last revision of a specified page.
	 * @param Parser $parser
	 * @param string|null $title Title to get the month from
	 * @return string
	 * @since 1.23
	 */
	public static function revisionmonth( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return self::getRevisionTimestampSubstring(
			$parser, $t, 4, 2, self::MAX_TTS
		);
	}

	/**
	 * Get the month from the last revision of a specified page.
	 * @param Parser $parser
	 * @param string|null $title Title to get the month from
	 * @return string
	 * @since 1.23
	 */
	public static function revisionmonth1( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return strval( (int)self::getRevisionTimestampSubstring(
			$parser, $t, 4, 2, self::MAX_TTS
		) );
	}

	/**
	 * Get the year from the last revision of a specified page.
	 * @param Parser $parser
	 * @param string|null $title Title to get the year from
	 * @return string
	 * @since 1.23
	 */
	public static function revisionyear( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return self::getRevisionTimestampSubstring(
			$parser, $t, 0, 4, self::MAX_TTS
		);
	}

	/**
	 * Get the timestamp from the last revision of a specified page.
	 * @param Parser $parser
	 * @param string|null $title Title to get the timestamp from
	 * @return string
	 * @since 1.23
	 */
	public static function revisiontimestamp( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		return self::getRevisionTimestampSubstring(
			$parser, $t, 0, 14, self::MAX_TTS
		);
	}

	/**
	 * Get the user from the last revision of a specified page.
	 * @param Parser $parser
	 * @param string|null $title Title to get the user from
	 * @return string
	 * @since 1.23
	 */
	public static function revisionuser( $parser, $title = null ) {
		$t = self::makeTitle( $parser, $title );
		if ( $t === null ) {
			return '';
		}
		// VARY_USER informs the edit saving system that getting the canonical
		// output after revision insertion requires a parse that used the
		// actual user ID.
		if ( $t->equals( $parser->getTitle() ) ) {
			// Fall back to Parser's "revision user" for the current title
			$parser->getOutput()->setOutputFlag( ParserOutputFlags::VARY_USER );
			// Note that getRevisionUser() can return null; we need to
			// be sure to cast this to (an empty) string, since returning
			// null means "magic variable not handled".
			return (string)$parser->getRevisionUser();
		}
		// Fetch revision from cache/database and return the value.
		$rev = self::getCachedRevisionObject( $parser, $t, ParserOutputFlags::VARY_USER );
		$user = ( $rev !== null ) ? $rev->getUser() : null;
		return $user ? $user->getName() : '';
	}

	/**
	 * Returns the sources of any cascading protection acting on a specified page.
	 * Pages will not return their own title unless they transclude themselves.
	 * This is an expensive parser function and can't be called too many times per page,
	 * unless cascading protection sources for the page have already been loaded.
	 *
	 * @param Parser $parser
	 * @param ?string $title
	 *
	 * @return string
	 * @since 1.23
	 */
	public static function cascadingsources( $parser, $title = '' ) {
		$titleObject = Title::newFromText( $title ) ?? $parser->getTitle();
		$restrictionStore = MediaWikiServices::getInstance()->getRestrictionStore();
		if ( $restrictionStore->areCascadeProtectionSourcesLoaded( $titleObject )
			|| $parser->incrementExpensiveFunctionCount()
		) {
			$names = [];
			$sources = $restrictionStore->getCascadeProtectionSources( $titleObject );
			$titleFormatter = MediaWikiServices::getInstance()->getTitleFormatter();
			foreach ( $sources[0] as $sourcePageIdentity ) {
				$names[] = $titleFormatter->getPrefixedText( $sourcePageIdentity );
			}
			return implode( '|', $names );
		}
		return '';
	}
}
