first commit

1 files changed, 1162 insertions, 0 deletions

diff --git a/www/wiki/languages/LanguageConverter.php b/www/wiki/languages/LanguageConverter.php
new file mode 100644
index 00000000..24b1d0c0
--- /dev/null
+++ b/www/wiki/languages/LanguageConverter.php
@@ -0,0 +1,1162 @@
+<?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
+ * @ingroup Language
+ */
+use MediaWiki\MediaWikiServices;
+
+use MediaWiki\Logger\LoggerFactory;
+
+/**
+ * Base class for language conversion.
+ * @ingroup Language
+ *
+ * @author Zhengzhu Feng <zhengzhu@gmail.com>
+ * @author fdcn <fdcn64@gmail.com>
+ * @author shinjiman <shinjiman@gmail.com>
+ * @author PhiLiP <philip.npc@gmail.com>
+ */
+class LanguageConverter {
+	/**
+	 * languages supporting variants
+	 * @since 1.20
+	 * @var array
+	 */
+	static public $languagesWithVariants = [
+		'en',
+		'crh',
+		'gan',
+		'iu',
+		'kk',
+		'ku',
+		'shi',
+		'sr',
+		'tg',
+		'uz',
+		'zh',
+	];
+
+	public $mMainLanguageCode;
+
+	/**
+	 * @var string[]
+	 */
+	public $mVariants;
+	public $mVariantFallbacks;
+	public $mVariantNames;
+	public $mTablesLoaded = false;
+	public $mTables;
+	// 'bidirectional' 'unidirectional' 'disable' for each variant
+	public $mManualLevel;
+
+	public $mLangObj;
+	public $mFlags;
+	public $mDescCodeSep = ':', $mDescVarSep = ';';
+	public $mUcfirst = false;
+	public $mConvRuleTitle = false;
+	public $mURLVariant;
+	public $mUserVariant;
+	public $mHeaderVariant;
+	public $mMaxDepth = 10;
+	public $mVarSeparatorPattern;
+
+	const CACHE_VERSION_KEY = 'VERSION 7';
+
+	/**
+	 * @param Language $langobj
+	 * @param string $maincode The main language code of this language
+	 * @param string[] $variants The supported variants of this language
+	 * @param array $variantfallbacks The fallback language of each variant
+	 * @param array $flags Defining the custom strings that maps to the flags
+	 * @param array $manualLevel Limit for supported variants
+	 */
+	public function __construct( $langobj, $maincode, $variants = [],
+								$variantfallbacks = [], $flags = [],
+								$manualLevel = [] ) {
+		global $wgDisabledVariants;
+		$this->mLangObj = $langobj;
+		$this->mMainLanguageCode = $maincode;
+		$this->mVariants = array_diff( $variants, $wgDisabledVariants );
+		$this->mVariantFallbacks = $variantfallbacks;
+		$this->mVariantNames = Language::fetchLanguageNames();
+		$defaultflags = [
+			// 'S' show converted text
+			// '+' add rules for alltext
+			// 'E' the gave flags is error
+			// these flags above are reserved for program
+			'A' => 'A',   // add rule for convert code (all text convert)
+			'T' => 'T',   // title convert
+			'R' => 'R',   // raw content
+			'D' => 'D',   // convert description (subclass implement)
+			'-' => '-',   // remove convert (not implement)
+			'H' => 'H',   // add rule for convert code (but no display in placed code)
+			'N' => 'N',   // current variant name
+		];
+		$this->mFlags = array_merge( $defaultflags, $flags );
+		foreach ( $this->mVariants as $v ) {
+			if ( array_key_exists( $v, $manualLevel ) ) {
+				$this->mManualLevel[$v] = $manualLevel[$v];
+			} else {
+				$this->mManualLevel[$v] = 'bidirectional';
+			}
+			$this->mFlags[$v] = $v;
+		}
+	}
+
+	/**
+	 * Get all valid variants.
+	 * Call this instead of using $this->mVariants directly.
+	 *
+	 * @return string[] Contains all valid variants
+	 */
+	public function getVariants() {
+		return $this->mVariants;
+	}
+
+	/**
+	 * In case some variant is not defined in the markup, we need
+	 * to have some fallback. For example, in zh, normally people
+	 * will define zh-hans and zh-hant, but less so for zh-sg or zh-hk.
+	 * when zh-sg is preferred but not defined, we will pick zh-hans
+	 * in this case. Right now this is only used by zh.
+	 *
+	 * @param string $variant The language code of the variant
+	 * @return string|array The code of the fallback language or the
+	 *   main code if there is no fallback
+	 */
+	public function getVariantFallbacks( $variant ) {
+		if ( isset( $this->mVariantFallbacks[$variant] ) ) {
+			return $this->mVariantFallbacks[$variant];
+		}
+		return $this->mMainLanguageCode;
+	}
+
+	/**
+	 * Get the title produced by the conversion rule.
+	 * @return string The converted title text
+	 */
+	public function getConvRuleTitle() {
+		return $this->mConvRuleTitle;
+	}
+
+	/**
+	 * Get preferred language variant.
+	 * @return string The preferred language code
+	 */
+	public function getPreferredVariant() {
+		global $wgDefaultLanguageVariant, $wgUser;
+
+		$req = $this->getURLVariant();
+
+		Hooks::run( 'GetLangPreferredVariant', [ &$req ] );
+
+		if ( $wgUser->isSafeToLoad() && $wgUser->isLoggedIn() && !$req ) {
+			$req = $this->getUserVariant();
+		} elseif ( !$req ) {
+			$req = $this->getHeaderVariant();
+		}
+
+		if ( $wgDefaultLanguageVariant && !$req ) {
+			$req = $this->validateVariant( $wgDefaultLanguageVariant );
+		}
+
+		// This function, unlike the other get*Variant functions, is
+		// not memoized (i.e. there return value is not cached) since
+		// new information might appear during processing after this
+		// is first called.
+		if ( $this->validateVariant( $req ) ) {
+			return $req;
+		}
+		return $this->mMainLanguageCode;
+	}
+
+	/**
+	 * Get default variant.
+	 * This function would not be affected by user's settings
+	 * @return string The default variant code
+	 */
+	public function getDefaultVariant() {
+		global $wgDefaultLanguageVariant;
+
+		$req = $this->getURLVariant();
+
+		if ( !$req ) {
+			$req = $this->getHeaderVariant();
+		}
+
+		if ( $wgDefaultLanguageVariant && !$req ) {
+			$req = $this->validateVariant( $wgDefaultLanguageVariant );
+		}
+
+		if ( $req ) {
+			return $req;
+		}
+		return $this->mMainLanguageCode;
+	}
+
+	/**
+	 * Validate the variant
+	 * @param string $variant The variant to validate
+	 * @return mixed Returns the variant if it is valid, null otherwise
+	 */
+	public function validateVariant( $variant = null ) {
+		if ( $variant !== null && in_array( $variant, $this->mVariants ) ) {
+			return $variant;
+		}
+		return null;
+	}
+
+	/**
+	 * Get the variant specified in the URL
+	 *
+	 * @return mixed Variant if one found, false otherwise.
+	 */
+	public function getURLVariant() {
+		global $wgRequest;
+
+		if ( $this->mURLVariant ) {
+			return $this->mURLVariant;
+		}
+
+		// see if the preference is set in the request
+		$ret = $wgRequest->getText( 'variant' );
+
+		if ( !$ret ) {
+			$ret = $wgRequest->getVal( 'uselang' );
+		}
+
+		$this->mURLVariant = $this->validateVariant( $ret );
+		return $this->mURLVariant;
+	}
+
+	/**
+	 * Determine if the user has a variant set.
+	 *
+	 * @return mixed Variant if one found, false otherwise.
+	 */
+	protected function getUserVariant() {
+		global $wgUser, $wgContLang;
+
+		// memoizing this function wreaks havoc on parserTest.php
+		/*
+		if ( $this->mUserVariant ) {
+			return $this->mUserVariant;
+		}
+		*/
+
+		// Get language variant preference from logged in users
+		// Don't call this on stub objects because that causes infinite
+		// recursion during initialisation
+		if ( !$wgUser->isSafeToLoad() ) {
+			return false;
+		}
+		if ( $wgUser->isLoggedIn() ) {
+			if ( $this->mMainLanguageCode == $wgContLang->getCode() ) {
+				$ret = $wgUser->getOption( 'variant' );
+			} else {
+				$ret = $wgUser->getOption( 'variant-' . $this->mMainLanguageCode );
+			}
+		} else {
+			// figure out user lang without constructing wgLang to avoid
+			// infinite recursion
+			$ret = $wgUser->getOption( 'language' );
+		}
+
+		$this->mUserVariant = $this->validateVariant( $ret );
+		return $this->mUserVariant;
+	}
+
+	/**
+	 * Determine the language variant from the Accept-Language header.
+	 *
+	 * @return mixed Variant if one found, false otherwise.
+	 */
+	protected function getHeaderVariant() {
+		global $wgRequest;
+
+		if ( $this->mHeaderVariant ) {
+			return $this->mHeaderVariant;
+		}
+
+		// see if some supported language variant is set in the
+		// HTTP header.
+		$languages = array_keys( $wgRequest->getAcceptLang() );
+		if ( empty( $languages ) ) {
+			return null;
+		}
+
+		$fallbackLanguages = [];
+		foreach ( $languages as $language ) {
+			$this->mHeaderVariant = $this->validateVariant( $language );
+			if ( $this->mHeaderVariant ) {
+				break;
+			}
+
+			// To see if there are fallbacks of current language.
+			// We record these fallback variants, and process
+			// them later.
+			$fallbacks = $this->getVariantFallbacks( $language );
+			if ( is_string( $fallbacks ) && $fallbacks !== $this->mMainLanguageCode ) {
+				$fallbackLanguages[] = $fallbacks;
+			} elseif ( is_array( $fallbacks ) ) {
+				$fallbackLanguages =
+					array_merge( $fallbackLanguages, $fallbacks );
+			}
+		}
+
+		if ( !$this->mHeaderVariant ) {
+			// process fallback languages now
+			$fallback_languages = array_unique( $fallbackLanguages );
+			foreach ( $fallback_languages as $language ) {
+				$this->mHeaderVariant = $this->validateVariant( $language );
+				if ( $this->mHeaderVariant ) {
+					break;
+				}
+			}
+		}
+
+		return $this->mHeaderVariant;
+	}
+
+	/**
+	 * Dictionary-based conversion.
+	 * This function would not parse the conversion rules.
+	 * If you want to parse rules, try to use convert() or
+	 * convertTo().
+	 *
+	 * @param string $text The text to be converted
+	 * @param bool|string $toVariant The target language code
+	 * @return string The converted text
+	 */
+	public function autoConvert( $text, $toVariant = false ) {
+		$this->loadTables();
+
+		if ( !$toVariant ) {
+			$toVariant = $this->getPreferredVariant();
+			if ( !$toVariant ) {
+				return $text;
+			}
+		}
+
+		if ( $this->guessVariant( $text, $toVariant ) ) {
+			return $text;
+		}
+		/* we convert everything except:
+		   1. HTML markups (anything between < and >)
+		   2. HTML entities
+		   3. placeholders created by the parser
+		   IMPORTANT: Beware of failure from pcre.backtrack_limit (T124404).
+		   Minimize use of backtracking where possible.
+		*/
+		$marker = '|' . Parser::MARKER_PREFIX . '[^\x7f]++\x7f';
+
+		// this one is needed when the text is inside an HTML markup
+		$htmlfix = '|<[^>\004]++(?=\004$)|^[^<>]*+>';
+
+		// Optimize for the common case where these tags have
+		// few or no children. Thus try and possesively get as much as
+		// possible, and only engage in backtracking when we hit a '<'.
+
+		// disable convert to variants between <code> tags
+		$codefix = '<code>[^<]*+(?:(?:(?!<\/code>).)[^<]*+)*+<\/code>|';
+		// disable conversion of <script> tags
+		$scriptfix = '<script[^>]*+>[^<]*+(?:(?:(?!<\/script>).)[^<]*+)*+<\/script>|';
+		// disable conversion of <pre> tags
+		$prefix = '<pre[^>]*+>[^<]*+(?:(?:(?!<\/pre>).)[^<]*+)*+<\/pre>|';
+		// The "|.*+)" at the end, is in case we missed some part of html syntax,
+		// we will fail securely (hopefully) by matching the rest of the string.
+		$htmlFullTag = '<(?:[^>=]*+(?>[^>=]*+=\s*+(?:"[^"]*"|\'[^\']*\'|[^\'">\s]*+))*+[^>=]*+>|.*+)|';
+
+		$reg = '/' . $codefix . $scriptfix . $prefix . $htmlFullTag .
+			'&[a-zA-Z#][a-z0-9]++;' . $marker . $htmlfix . '|\004$/s';
+		$startPos = 0;
+		$sourceBlob = '';
+		$literalBlob = '';
+
+		// Guard against delimiter nulls in the input
+		// (should never happen: see T159174)
+		$text = str_replace( "\000", '', $text );
+		$text = str_replace( "\004", '', $text );
+
+		$markupMatches = null;
+		$elementMatches = null;
+
+		// We add a marker (\004) at the end of text, to ensure we always match the
+		// entire text (Otherwise, pcre.backtrack_limit might cause silent failure)
+		while ( $startPos < strlen( $text ) ) {
+			if ( preg_match( $reg, $text . "\004", $markupMatches, PREG_OFFSET_CAPTURE, $startPos ) ) {
+				$elementPos = $markupMatches[0][1];
+				$element = $markupMatches[0][0];
+				if ( $element === "\004" ) {
+					// We hit the end.
+					$elementPos = strlen( $text );
+					$element = '';
+				} elseif ( substr( $element, -1 ) === "\004" ) {
+					// This can sometimes happen if we have
+					// unclosed html tags (For example
+					// when converting a title attribute
+					// during a recursive call that contains
+					// a &lt; e.g. <div title="&lt;">.
+					$element = substr( $element, 0, -1 );
+				}
+			} else {
+				// If we hit here, then Language Converter could be tricked
+				// into doing an XSS, so we refuse to translate.
+				// If non-crazy input manages to reach this code path,
+				// we should consider it a bug.
+				$log = LoggerFactory::getInstance( 'languageconverter' );
+				$log->error( "Hit pcre.backtrack_limit in " . __METHOD__
+					. ". Disabling language conversion for this page.",
+					[
+						"method" => __METHOD__,
+						"variant" => $toVariant,
+						"startOfText" => substr( $text, 0, 500 )
+					]
+				);
+				return $text;
+			}
+			// Queue the part before the markup for translation in a batch
+			$sourceBlob .= substr( $text, $startPos, $elementPos - $startPos ) . "\000";
+
+			// Advance to the next position
+			$startPos = $elementPos + strlen( $element );
+
+			// Translate any alt or title attributes inside the matched element
+			if ( $element !== ''
+				&& preg_match( '/^(<[^>\s]*+)\s([^>]*+)(.*+)$/', $element, $elementMatches )
+			) {
+				// FIXME, this decodes entities, so if you have something
+				// like <div title="foo&lt;bar"> the bar won't get
+				// translated since after entity decoding it looks like
+				// unclosed html and we call this method recursively
+				// on attributes.
+				$attrs = Sanitizer::decodeTagAttributes( $elementMatches[2] );
+				// Ensure self-closing tags stay self-closing.
+				$close = substr( $elementMatches[2], -1 ) === '/' ? ' /' : '';
+				$changed = false;
+				foreach ( [ 'title', 'alt' ] as $attrName ) {
+					if ( !isset( $attrs[$attrName] ) ) {
+						continue;
+					}
+					$attr = $attrs[$attrName];
+					// Don't convert URLs
+					if ( !strpos( $attr, '://' ) ) {
+						$attr = $this->recursiveConvertTopLevel( $attr, $toVariant );
+					}
+
+					if ( $attr !== $attrs[$attrName] ) {
+						$attrs[$attrName] = $attr;
+						$changed = true;
+					}
+				}
+				if ( $changed ) {
+					$element = $elementMatches[1] . Html::expandAttributes( $attrs ) .
+						$close . $elementMatches[3];
+				}
+			}
+			$literalBlob .= $element . "\000";
+		}
+
+		// Do the main translation batch
+		$translatedBlob = $this->translate( $sourceBlob, $toVariant );
+
+		// Put the output back together
+		$translatedIter = StringUtils::explode( "\000", $translatedBlob );
+		$literalIter = StringUtils::explode( "\000", $literalBlob );
+		$output = '';
+		while ( $translatedIter->valid() && $literalIter->valid() ) {
+			$output .= $translatedIter->current();
+			$output .= $literalIter->current();
+			$translatedIter->next();
+			$literalIter->next();
+		}
+
+		return $output;
+	}
+
+	/**
+	 * Translate a string to a variant.
+	 * Doesn't parse rules or do any of that other stuff, for that use
+	 * convert() or convertTo().
+	 *
+	 * @param string $text Text to convert
+	 * @param string $variant Variant language code
+	 * @return string Translated text
+	 */
+	public function translate( $text, $variant ) {
+		// If $text is empty or only includes spaces, do nothing
+		// Otherwise translate it
+		if ( trim( $text ) ) {
+			$this->loadTables();
+			$text = $this->mTables[$variant]->replace( $text );
+		}
+		return $text;
+	}
+
+	/**
+	 * Call translate() to convert text to all valid variants.
+	 *
+	 * @param string $text The text to be converted
+	 * @return array Variant => converted text
+	 */
+	public function autoConvertToAllVariants( $text ) {
+		$this->loadTables();
+
+		$ret = [];
+		foreach ( $this->mVariants as $variant ) {
+			$ret[$variant] = $this->translate( $text, $variant );
+		}
+
+		return $ret;
+	}
+
+	/**
+	 * Apply manual conversion rules.
+	 *
+	 * @param ConverterRule $convRule
+	 */
+	protected function applyManualConv( $convRule ) {
+		// Use syntax -{T|zh-cn:TitleCN; zh-tw:TitleTw}- to custom
+		// title conversion.
+		// T26072: $mConvRuleTitle was overwritten by other manual
+		// rule(s) not for title, this breaks the title conversion.
+		$newConvRuleTitle = $convRule->getTitle();
+		if ( $newConvRuleTitle ) {
+			// So I add an empty check for getTitle()
+			$this->mConvRuleTitle = $newConvRuleTitle;
+		}
+
+		// merge/remove manual conversion rules to/from global table
+		$convTable = $convRule->getConvTable();
+		$action = $convRule->getRulesAction();
+		foreach ( $convTable as $variant => $pair ) {
+			if ( !$this->validateVariant( $variant ) ) {
+				continue;
+			}
+
+			if ( $action == 'add' ) {
+				// More efficient than array_merge(), about 2.5 times.
+				foreach ( $pair as $from => $to ) {
+					$this->mTables[$variant]->setPair( $from, $to );
+				}
+			} elseif ( $action == 'remove' ) {
+				$this->mTables[$variant]->removeArray( $pair );
+			}
+		}
+	}
+
+	/**
+	 * Auto convert a Title object to a readable string in the
+	 * preferred variant.
+	 *
+	 * @param Title $title A object of Title
+	 * @return string Converted title text
+	 */
+	public function convertTitle( $title ) {
+		$variant = $this->getPreferredVariant();
+		$index = $title->getNamespace();
+		if ( $index !== NS_MAIN ) {
+			$text = $this->convertNamespace( $index, $variant ) . ':';
+		} else {
+			$text = '';
+		}
+		$text .= $this->translate( $title->getText(), $variant );
+		return $text;
+	}
+
+	/**
+	 * Get the namespace display name in the preferred variant.
+	 *
+	 * @param int $index Namespace id
+	 * @param string|null $variant Variant code or null for preferred variant
+	 * @return string Namespace name for display
+	 */
+	public function convertNamespace( $index, $variant = null ) {
+		if ( $index === NS_MAIN ) {
+			return '';
+		}
+
+		if ( $variant === null ) {
+			$variant = $this->getPreferredVariant();
+		}
+
+		$cache = MediaWikiServices::getInstance()->getLocalServerObjectCache();
+		$key = $cache->makeKey( 'languageconverter', 'namespace-text', $index, $variant );
+		$nsVariantText = $cache->get( $key );
+		if ( $nsVariantText !== false ) {
+			return $nsVariantText;
+		}
+
+		// First check if a message gives a converted name in the target variant.
+		$nsConvMsg = wfMessage( 'conversion-ns' . $index )->inLanguage( $variant );
+		if ( $nsConvMsg->exists() ) {
+			$nsVariantText = $nsConvMsg->plain();
+		}
+
+		// Then check if a message gives a converted name in content language
+		// which needs extra translation to the target variant.
+		if ( $nsVariantText === false ) {
+			$nsConvMsg = wfMessage( 'conversion-ns' . $index )->inContentLanguage();
+			if ( $nsConvMsg->exists() ) {
+				$nsVariantText = $this->translate( $nsConvMsg->plain(), $variant );
+			}
+		}
+
+		if ( $nsVariantText === false ) {
+			// No message exists, retrieve it from the target variant's namespace names.
+			$langObj = $this->mLangObj->factory( $variant );
+			$nsVariantText = $langObj->getFormattedNsText( $index );
+		}
+
+		$cache->set( $key, $nsVariantText, 60 );
+
+		return $nsVariantText;
+	}
+
+	/**
+	 * Convert text to different variants of a language. The automatic
+	 * conversion is done in autoConvert(). Here we parse the text
+	 * marked with -{}-, which specifies special conversions of the
+	 * text that can not be accomplished in autoConvert().
+	 *
+	 * Syntax of the markup:
+	 * -{code1:text1;code2:text2;...}-  or
+	 * -{flags|code1:text1;code2:text2;...}-  or
+	 * -{text}- in which case no conversion should take place for text
+	 *
+	 * @param string $text Text to be converted
+	 * @return string Converted text
+	 */
+	public function convert( $text ) {
+		$variant = $this->getPreferredVariant();
+		return $this->convertTo( $text, $variant );
+	}
+
+	/**
+	 * Same as convert() except a extra parameter to custom variant.
+	 *
+	 * @param string $text Text to be converted
+	 * @param string $variant The target variant code
+	 * @return string Converted text
+	 */
+	public function convertTo( $text, $variant ) {
+		global $wgDisableLangConversion;
+		if ( $wgDisableLangConversion ) {
+			return $text;
+		}
+		// Reset converter state for a new converter run.
+		$this->mConvRuleTitle = false;
+		return $this->recursiveConvertTopLevel( $text, $variant );
+	}
+
+	/**
+	 * Recursively convert text on the outside. Allow to use nested
+	 * markups to custom rules.
+	 *
+	 * @param string $text Text to be converted
+	 * @param string $variant The target variant code
+	 * @param int $depth Depth of recursion
+	 * @return string Converted text
+	 */
+	protected function recursiveConvertTopLevel( $text, $variant, $depth = 0 ) {
+		$startPos = 0;
+		$out = '';
+		$length = strlen( $text );
+		$shouldConvert = !$this->guessVariant( $text, $variant );
+		$continue = 1;
+
+		$noScript = '<script.*?>.*?<\/script>(*SKIP)(*FAIL)';
+		$noStyle = '<style.*?>.*?<\/style>(*SKIP)(*FAIL)';
+		// phpcs:ignore Generic.Files.LineLength
+		$noHtml = '<(?:[^>=]*+(?>[^>=]*+=\s*+(?:"[^"]*"|\'[^\']*\'|[^\'">\s]*+))*+[^>=]*+>|.*+)(*SKIP)(*FAIL)';
+		while ( $startPos < $length && $continue ) {
+			$continue = preg_match(
+				// Only match -{ outside of html.
+				"/$noScript|$noStyle|$noHtml|-\{/",
+				$text,
+				$m,
+				PREG_OFFSET_CAPTURE,
+				$startPos
+			);
+
+			if ( !$continue ) {
+				// No more markup, append final segment
+				$fragment = substr( $text, $startPos );
+				$out .= $shouldConvert ? $this->autoConvert( $fragment, $variant ) : $fragment;
+				return $out;
+			}
+
+			// Offset of the match of the regex pattern.
+			$pos = $m[0][1];
+
+			// Append initial segment
+			$fragment = substr( $text, $startPos, $pos - $startPos );
+			$out .= $shouldConvert ? $this->autoConvert( $fragment, $variant ) : $fragment;
+			// -{ marker found, not in attribute
+			// Advance position up to -{ marker.
+			$startPos = $pos;
+			// Do recursive conversion
+			// Note: This passes $startPos by reference, and advances it.
+			$out .= $this->recursiveConvertRule( $text, $variant, $startPos, $depth + 1 );
+		}
+		return $out;
+	}
+
+	/**
+	 * Recursively convert text on the inside.
+	 *
+	 * @param string $text Text to be converted
+	 * @param string $variant The target variant code
+	 * @param int &$startPos
+	 * @param int $depth Depth of recursion
+	 *
+	 * @throws MWException
+	 * @return string Converted text
+	 */
+	protected function recursiveConvertRule( $text, $variant, &$startPos, $depth = 0 ) {
+		// Quick sanity check (no function calls)
+		if ( $text[$startPos] !== '-' || $text[$startPos + 1] !== '{' ) {
+			throw new MWException( __METHOD__ . ': invalid input string' );
+		}
+
+		$startPos += 2;
+		$inner = '';
+		$warningDone = false;
+		$length = strlen( $text );
+
+		while ( $startPos < $length ) {
+			$m = false;
+			preg_match( '/-\{|\}-/', $text, $m, PREG_OFFSET_CAPTURE, $startPos );
+			if ( !$m ) {
+				// Unclosed rule
+				break;
+			}
+
+			$token = $m[0][0];
+			$pos = $m[0][1];
+
+			// Markup found
+			// Append initial segment
+			$inner .= substr( $text, $startPos, $pos - $startPos );
+
+			// Advance position
+			$startPos = $pos;
+
+			switch ( $token ) {
+				case '-{':
+					// Check max depth
+					if ( $depth >= $this->mMaxDepth ) {
+						$inner .= '-{';
+						if ( !$warningDone ) {
+							$inner .= '<span class="error">' .
+								wfMessage( 'language-converter-depth-warning' )
+									->numParams( $this->mMaxDepth )->inContentLanguage()->text() .
+								'</span>';
+							$warningDone = true;
+						}
+						$startPos += 2;
+						break;
+					}
+					// Recursively parse another rule
+					$inner .= $this->recursiveConvertRule( $text, $variant, $startPos, $depth + 1 );
+					break;
+				case '}-':
+					// Apply the rule
+					$startPos += 2;
+					$rule = new ConverterRule( $inner, $this );
+					$rule->parse( $variant );
+					$this->applyManualConv( $rule );
+					return $rule->getDisplay();
+				default:
+					throw new MWException( __METHOD__ . ': invalid regex match' );
+			}
+		}
+
+		// Unclosed rule
+		if ( $startPos < $length ) {
+			$inner .= substr( $text, $startPos );
+		}
+		$startPos = $length;
+		return '-{' . $this->autoConvert( $inner, $variant );
+	}
+
+	/**
+	 * If a language supports multiple variants, it is possible that
+	 * non-existing link in one variant actually exists in another variant.
+	 * This function tries to find it. See e.g. LanguageZh.php
+	 * The input parameters may be modified upon return
+	 *
+	 * @param string &$link The name of the link
+	 * @param Title &$nt The title object of the link
+	 * @param bool $ignoreOtherCond To disable other conditions when
+	 *   we need to transclude a template or update a category's link
+	 */
+	public function findVariantLink( &$link, &$nt, $ignoreOtherCond = false ) {
+		# If the article has already existed, there is no need to
+		# check it again, otherwise it may cause a fault.
+		if ( is_object( $nt ) && $nt->exists() ) {
+			return;
+		}
+
+		global $wgDisableLangConversion, $wgDisableTitleConversion, $wgRequest;
+		$isredir = $wgRequest->getText( 'redirect', 'yes' );
+		$action = $wgRequest->getText( 'action' );
+		if ( $action == 'edit' && $wgRequest->getBool( 'redlink' ) ) {
+			$action = 'view';
+		}
+		$linkconvert = $wgRequest->getText( 'linkconvert', 'yes' );
+		$disableLinkConversion = $wgDisableLangConversion
+			|| $wgDisableTitleConversion;
+		$linkBatch = new LinkBatch();
+
+		$ns = NS_MAIN;
+
+		if ( $disableLinkConversion ||
+			( !$ignoreOtherCond &&
+				( $isredir == 'no'
+					|| $action == 'edit'
+					|| $action == 'submit'
+					|| $linkconvert == 'no' ) ) ) {
+			return;
+		}
+
+		if ( is_object( $nt ) ) {
+			$ns = $nt->getNamespace();
+		}
+
+		$variants = $this->autoConvertToAllVariants( $link );
+		if ( !$variants ) { // give up
+			return;
+		}
+
+		$titles = [];
+
+		foreach ( $variants as $v ) {
+			if ( $v != $link ) {
+				$varnt = Title::newFromText( $v, $ns );
+				if ( !is_null( $varnt ) ) {
+					$linkBatch->addObj( $varnt );
+					$titles[] = $varnt;
+				}
+			}
+		}
+
+		// fetch all variants in single query
+		$linkBatch->execute();
+
+		foreach ( $titles as $varnt ) {
+			if ( $varnt->getArticleID() > 0 ) {
+				$nt = $varnt;
+				$link = $varnt->getText();
+				break;
+			}
+		}
+	}
+
+	/**
+	 * Returns language specific hash options.
+	 *
+	 * @return string
+	 */
+	public function getExtraHashOptions() {
+		$variant = $this->getPreferredVariant();
+
+		return '!' . $variant;
+	}
+
+	/**
+	 * Guess if a text is written in a variant. This should be implemented in subclasses.
+	 *
+	 * @param string $text The text to be checked
+	 * @param string $variant Language code of the variant to be checked for
+	 * @return bool True if $text appears to be written in $variant, false if not
+	 *
+	 * @author Nikola Smolenski <smolensk@eunet.rs>
+	 * @since 1.19
+	 */
+	public function guessVariant( $text, $variant ) {
+		return false;
+	}
+
+	/**
+	 * Load default conversion tables.
+	 * This method must be implemented in derived class.
+	 *
+	 * @private
+	 * @throws MWException
+	 */
+	function loadDefaultTables() {
+		$class = static::class;
+		throw new MWException( "Must implement loadDefaultTables() method in class $class" );
+	}
+
+	/**
+	 * Load conversion tables either from the cache or the disk.
+	 * @private
+	 * @param bool $fromCache Load from memcached? Defaults to true.
+	 */
+	function loadTables( $fromCache = true ) {
+		global $wgLanguageConverterCacheType;
+
+		if ( $this->mTablesLoaded ) {
+			return;
+		}
+
+		$this->mTablesLoaded = true;
+		$this->mTables = false;
+		$cache = ObjectCache::getInstance( $wgLanguageConverterCacheType );
+		$cacheKey = $cache->makeKey( 'conversiontables', $this->mMainLanguageCode );
+		if ( $fromCache ) {
+			$this->mTables = $cache->get( $cacheKey );
+		}
+		if ( !$this->mTables || !array_key_exists( self::CACHE_VERSION_KEY, $this->mTables ) ) {
+			// not in cache, or we need a fresh reload.
+			// We will first load the default tables
+			// then update them using things in MediaWiki:Conversiontable/*
+			$this->loadDefaultTables();
+			foreach ( $this->mVariants as $var ) {
+				$cached = $this->parseCachedTable( $var );
+				$this->mTables[$var]->mergeArray( $cached );
+			}
+
+			$this->postLoadTables();
+			$this->mTables[self::CACHE_VERSION_KEY] = true;
+
+			$cache->set( $cacheKey, $this->mTables, 43200 );
+		}
+	}
+
+	/**
+	 * Hook for post processing after conversion tables are loaded.
+	 */
+	function postLoadTables() {
+	}
+
+	/**
+	 * Reload the conversion tables.
+	 *
+	 * Also used by test suites which need to reset the converter state.
+	 *
+	 * @private
+	 */
+	private function reloadTables() {
+		if ( $this->mTables ) {
+			unset( $this->mTables );
+		}
+
+		$this->mTablesLoaded = false;
+		$this->loadTables( false );
+	}
+
+	/**
+	 * Parse the conversion table stored in the cache.
+	 *
+	 * The tables should be in blocks of the following form:
+	 *		-{
+	 *			word => word ;
+	 *			word => word ;
+	 *			...
+	 *		}-
+	 *
+	 * To make the tables more manageable, subpages are allowed
+	 * and will be parsed recursively if $recursive == true.
+	 *
+	 * @param string $code Language code
+	 * @param string $subpage Subpage name
+	 * @param bool $recursive Parse subpages recursively? Defaults to true.
+	 *
+	 * @return array
+	 */
+	function parseCachedTable( $code, $subpage = '', $recursive = true ) {
+		static $parsed = [];
+
+		$key = 'Conversiontable/' . $code;
+		if ( $subpage ) {
+			$key .= '/' . $subpage;
+		}
+		if ( array_key_exists( $key, $parsed ) ) {
+			return [];
+		}
+
+		$parsed[$key] = true;
+
+		if ( $subpage === '' ) {
+			$txt = MessageCache::singleton()->getMsgFromNamespace( $key, $code );
+		} else {
+			$txt = false;
+			$title = Title::makeTitleSafe( NS_MEDIAWIKI, $key );
+			if ( $title && $title->exists() ) {
+				$revision = Revision::newFromTitle( $title );
+				if ( $revision ) {
+					if ( $revision->getContentModel() == CONTENT_MODEL_WIKITEXT ) {
+						$txt = $revision->getContent( Revision::RAW )->getNativeData();
+					}
+
+					// @todo in the future, use a specialized content model, perhaps based on json!
+				}
+			}
+		}
+
+		# Nothing to parse if there's no text
+		if ( $txt === false || $txt === null || $txt === '' ) {
+			return [];
+		}
+
+		// get all subpage links of the form
+		// [[MediaWiki:Conversiontable/zh-xx/...|...]]
+		$linkhead = $this->mLangObj->getNsText( NS_MEDIAWIKI ) .
+			':Conversiontable';
+		$subs = StringUtils::explode( '[[', $txt );
+		$sublinks = [];
+		foreach ( $subs as $sub ) {
+			$link = explode( ']]', $sub, 2 );
+			if ( count( $link ) != 2 ) {
+				continue;
+			}
+			$b = explode( '|', $link[0], 2 );
+			$b = explode( '/', trim( $b[0] ), 3 );
+			if ( count( $b ) == 3 ) {
+				$sublink = $b[2];
+			} else {
+				$sublink = '';
+			}
+
+			if ( $b[0] == $linkhead && $b[1] == $code ) {
+				$sublinks[] = $sublink;
+			}
+		}
+
+		// parse the mappings in this page
+		$blocks = StringUtils::explode( '-{', $txt );
+		$ret = [];
+		$first = true;
+		foreach ( $blocks as $block ) {
+			if ( $first ) {
+				// Skip the part before the first -{
+				$first = false;
+				continue;
+			}
+			$mappings = explode( '}-', $block, 2 )[0];
+			$stripped = str_replace( [ "'", '"', '*', '#' ], '', $mappings );
+			$table = StringUtils::explode( ';', $stripped );
+			foreach ( $table as $t ) {
+				$m = explode( '=>', $t, 3 );
+				if ( count( $m ) != 2 ) {
+					continue;
+				}
+				// trim any trailling comments starting with '//'
+				$tt = explode( '//', $m[1], 2 );
+				$ret[trim( $m[0] )] = trim( $tt[0] );
+			}
+		}
+
+		// recursively parse the subpages
+		if ( $recursive ) {
+			foreach ( $sublinks as $link ) {
+				$s = $this->parseCachedTable( $code, $link, $recursive );
+				$ret = $s + $ret;
+			}
+		}
+
+		if ( $this->mUcfirst ) {
+			foreach ( $ret as $k => $v ) {
+				$ret[$this->mLangObj->ucfirst( $k )] = $this->mLangObj->ucfirst( $v );
+			}
+		}
+		return $ret;
+	}
+
+	/**
+	 * Enclose a string with the "no conversion" tag. This is used by
+	 * various functions in the Parser.
+	 *
+	 * @param string $text Text to be tagged for no conversion
+	 * @param bool $noParse Unused
+	 * @return string The tagged text
+	 */
+	public function markNoConversion( $text, $noParse = false ) {
+		# don't mark if already marked
+		if ( strpos( $text, '-{' ) || strpos( $text, '}-' ) ) {
+			return $text;
+		}
+
+		$ret = "-{R|$text}-";
+		return $ret;
+	}
+
+	/**
+	 * Convert the sorting key for category links. This should make different
+	 * keys that are variants of each other map to the same key.
+	 *
+	 * @param string $key
+	 *
+	 * @return string
+	 */
+	function convertCategoryKey( $key ) {
+		return $key;
+	}
+
+	/**
+	 * Refresh the cache of conversion tables when
+	 * MediaWiki:Conversiontable* is updated.
+	 *
+	 * @param Title $titleobj The Title of the page being updated
+	 */
+	public function updateConversionTable( Title $titleobj ) {
+		if ( $titleobj->getNamespace() == NS_MEDIAWIKI ) {
+			$title = $titleobj->getDBkey();
+			$t = explode( '/', $title, 3 );
+			$c = count( $t );
+			if ( $c > 1 && $t[0] == 'Conversiontable' ) {
+				if ( $this->validateVariant( $t[1] ) ) {
+					$this->reloadTables();
+				}
+			}
+		}
+	}
+
+	/**
+	 * Get the cached separator pattern for ConverterRule::parseRules()
+	 * @return string
+	 */
+	function getVarSeparatorPattern() {
+		if ( is_null( $this->mVarSeparatorPattern ) ) {
+			// varsep_pattern for preg_split:
+			// text should be splited by ";" only if a valid variant
+			// name exist after the markup, for example:
+			//  -{zh-hans:<span style="font-size:120%;">xxx</span>;zh-hant:\
+			//  <span style="font-size:120%;">yyy</span>;}-
+			// we should split it as:
+			//  [
+			//    [0] => 'zh-hans:<span style="font-size:120%;">xxx</span>'
+			//    [1] => 'zh-hant:<span style="font-size:120%;">yyy</span>'
+			//    [2] => ''
+			//  ]
+			$pat = '/;\s*(?=';
+			foreach ( $this->mVariants as $variant ) {
+				// zh-hans:xxx;zh-hant:yyy
+				$pat .= $variant . '\s*:|';
+				// xxx=>zh-hans:yyy; xxx=>zh-hant:zzz
+				$pat .= '[^;]*?=>\s*' . $variant . '\s*:|';
+			}
+			$pat .= '\s*$)/';
+			$this->mVarSeparatorPattern = $pat;
+		}
+		return $this->mVarSeparatorPattern;
+	}
+}