]> scripts.mit.edu Git - autoinstallsdev/mediawiki.git/blobdiff - languages/Language.php
MediaWiki 1.30.2
[autoinstallsdev/mediawiki.git] / languages / Language.php
index fee5aec3da1e21630fd9cd61010259b4010c9d21..c514cdc5952e19b08b997b220bc4e8d7dea33bba 100644 (file)
@@ -1,6 +1,22 @@
 <?php
 /**
- * Internationalisation code
+ * Internationalisation code.
+ * See https://www.mediawiki.org/wiki/Special:MyLanguage/Localisation for more information.
+ *
+ * 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
  * @defgroup Language Language
  */
 
-if ( !defined( 'MEDIAWIKI' ) ) {
-       echo "This file is part of MediaWiki, it is not a valid entry point.\n";
-       exit( 1 );
-}
-
-# Read language names
-global $wgLanguageNames;
-require_once( dirname( __FILE__ ) . '/Names.php' );
-
-global $wgInputEncoding, $wgOutputEncoding;
-
-/**
- * These are always UTF-8, they exist only for backwards compatibility
- */
-$wgInputEncoding    = 'UTF-8';
-$wgOutputEncoding      = 'UTF-8';
-
-if ( function_exists( 'mb_strtoupper' ) ) {
-       mb_internal_encoding( 'UTF-8' );
-}
-
-/**
- * a fake language converter
- *
- * @ingroup Language
- */
-class FakeConverter {
-       var $mLang;
-       function __construct( $langobj ) { $this->mLang = $langobj; }
-       function autoConvertToAllVariants( $text ) { return array( $this->mLang->getCode() => $text ); }
-       function convert( $t ) { return $t; }
-       function convertTitle( $t ) { return $t->getPrefixedText(); }
-       function getVariants() { return array( $this->mLang->getCode() ); }
-       function getPreferredVariant() { return $this->mLang->getCode(); }
-       function getDefaultVariant() { return $this->mLang->getCode(); }
-       function getURLVariant() { return ''; }
-       function getConvRuleTitle() { return false; }
-       function findVariantLink( &$l, &$n, $ignoreOtherCond = false ) { }
-       function getExtraHashOptions() { return ''; }
-       function getParsedTitle() { return ''; }
-       function markNoConversion( $text, $noParse = false ) { return $text; }
-       function convertCategoryKey( $key ) { return $key; }
-       function convertLinkToAllVariants( $text ) { return $this->autoConvertToAllVariants( $text ); }
-       function armourMath( $text ) { return $text; }
-}
+use CLDRPluralRuleParser\Evaluator;
 
 /**
  * Internationalisation code
  * @ingroup Language
  */
 class Language {
-       var $mConverter, $mVariants, $mCode, $mLoaded = false;
-       var $mMagicExtensions = array(), $mMagicHookDone = false;
+       /**
+        * @var LanguageConverter
+        */
+       public $mConverter;
 
-       var $mNamespaceIds, $namespaceNames, $namespaceAliases;
-       var $dateFormatStrings = array();
-       var $mExtendedSpecialPageAliases;
+       public $mVariants, $mCode, $mLoaded = false;
+       public $mMagicExtensions = [], $mMagicHookDone = false;
+       private $mHtmlCode = null, $mParentLanguage = false;
+
+       public $dateFormatStrings = [];
+       public $mExtendedSpecialPageAliases;
+
+       /** @var array|null */
+       protected $namespaceNames;
+       protected $mNamespaceIds, $namespaceAliases;
 
        /**
         * ReplacementArray object caches
         */
-       var $transformData = array();
+       public $transformData = [];
 
+       /**
+        * @var LocalisationCache
+        */
        static public $dataCache;
-       static public $mLangObjCache = array();
 
-       static public $mWeekdayMsgs = array(
+       static public $mLangObjCache = [];
+
+       static public $mWeekdayMsgs = [
                'sunday', 'monday', 'tuesday', 'wednesday', 'thursday',
                'friday', 'saturday'
-       );
+       ];
 
-       static public $mWeekdayAbbrevMsgs = array(
+       static public $mWeekdayAbbrevMsgs = [
                'sun', 'mon', 'tue', 'wed', 'thu', 'fri', 'sat'
-       );
+       ];
 
-       static public $mMonthMsgs = array(
+       static public $mMonthMsgs = [
                'january', 'february', 'march', 'april', 'may_long', 'june',
                'july', 'august', 'september', 'october', 'november',
                'december'
-       );
-       static public $mMonthGenMsgs = array(
+       ];
+       static public $mMonthGenMsgs = [
                'january-gen', 'february-gen', 'march-gen', 'april-gen', 'may-gen', 'june-gen',
                'july-gen', 'august-gen', 'september-gen', 'october-gen', 'november-gen',
                'december-gen'
-       );
-       static public $mMonthAbbrevMsgs = array(
+       ];
+       static public $mMonthAbbrevMsgs = [
                'jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul', 'aug',
                'sep', 'oct', 'nov', 'dec'
-       );
+       ];
 
-       static public $mIranianCalendarMonthMsgs = array(
+       static public $mIranianCalendarMonthMsgs = [
                'iranian-calendar-m1', 'iranian-calendar-m2', 'iranian-calendar-m3',
                'iranian-calendar-m4', 'iranian-calendar-m5', 'iranian-calendar-m6',
                'iranian-calendar-m7', 'iranian-calendar-m8', 'iranian-calendar-m9',
                'iranian-calendar-m10', 'iranian-calendar-m11', 'iranian-calendar-m12'
-       );
+       ];
 
-       static public $mHebrewCalendarMonthMsgs = array(
+       static public $mHebrewCalendarMonthMsgs = [
                'hebrew-calendar-m1', 'hebrew-calendar-m2', 'hebrew-calendar-m3',
                'hebrew-calendar-m4', 'hebrew-calendar-m5', 'hebrew-calendar-m6',
                'hebrew-calendar-m7', 'hebrew-calendar-m8', 'hebrew-calendar-m9',
                'hebrew-calendar-m10', 'hebrew-calendar-m11', 'hebrew-calendar-m12',
                'hebrew-calendar-m6a', 'hebrew-calendar-m6b'
-       );
+       ];
 
-       static public $mHebrewCalendarMonthGenMsgs = array(
+       static public $mHebrewCalendarMonthGenMsgs = [
                'hebrew-calendar-m1-gen', 'hebrew-calendar-m2-gen', 'hebrew-calendar-m3-gen',
                'hebrew-calendar-m4-gen', 'hebrew-calendar-m5-gen', 'hebrew-calendar-m6-gen',
                'hebrew-calendar-m7-gen', 'hebrew-calendar-m8-gen', 'hebrew-calendar-m9-gen',
                'hebrew-calendar-m10-gen', 'hebrew-calendar-m11-gen', 'hebrew-calendar-m12-gen',
                'hebrew-calendar-m6a-gen', 'hebrew-calendar-m6b-gen'
-       );
+       ];
 
-       static public $mHijriCalendarMonthMsgs = array(
+       static public $mHijriCalendarMonthMsgs = [
                'hijri-calendar-m1', 'hijri-calendar-m2', 'hijri-calendar-m3',
                'hijri-calendar-m4', 'hijri-calendar-m5', 'hijri-calendar-m6',
                'hijri-calendar-m7', 'hijri-calendar-m8', 'hijri-calendar-m9',
                'hijri-calendar-m10', 'hijri-calendar-m11', 'hijri-calendar-m12'
-       );
+       ];
+
+       /**
+        * @since 1.20
+        * @var array
+        */
+       static public $durationIntervals = [
+               'millennia' => 31556952000,
+               'centuries' => 3155695200,
+               'decades' => 315569520,
+               'years' => 31556952, // 86400 * ( 365 + ( 24 * 3 + 25 ) / 400 )
+               'weeks' => 604800,
+               'days' => 86400,
+               'hours' => 3600,
+               'minutes' => 60,
+               'seconds' => 1,
+       ];
+
+       /**
+        * Cache for language fallbacks.
+        * @see Language::getFallbacksIncludingSiteLanguage
+        * @since 1.21
+        * @var array
+        */
+       static private $fallbackLanguageCache = [];
+
+       /**
+        * Cache for grammar rules data
+        * @var MapCacheLRU|null
+        */
+       static private $grammarTransformations;
+
+       /**
+        * Cache for language names
+        * @var HashBagOStuff|null
+        */
+       static private $languageNameCache;
+
+       /**
+        * Unicode directional formatting characters, for embedBidi()
+        */
+       static private $lre = "\xE2\x80\xAA"; // U+202A LEFT-TO-RIGHT EMBEDDING
+       static private $rle = "\xE2\x80\xAB"; // U+202B RIGHT-TO-LEFT EMBEDDING
+       static private $pdf = "\xE2\x80\xAC"; // U+202C POP DIRECTIONAL FORMATTING
 
        /**
-        * Get a cached language object for a given language code
+        * Directionality test regex for embedBidi(). Matches the first strong directionality codepoint:
+        * - in group 1 if it is LTR
+        * - in group 2 if it is RTL
+        * Does not match if there is no strong directionality codepoint.
+        *
+        * The form is '/(?:([strong ltr codepoint])|([strong rtl codepoint]))/u' .
+        *
+        * Generated by UnicodeJS (see tools/strongDir) from the UCD; see
+        * https://git.wikimedia.org/summary/unicodejs.git .
+        */
+       // @codingStandardsIgnoreStart
+       // @codeCoverageIgnoreStart
+       static private $strongDirRegex = '/(?:([\x{41}-\x{5a}\x{61}-\x{7a}\x{aa}\x{b5}\x{ba}\x{c0}-\x{d6}\x{d8}-\x{f6}\x{f8}-\x{2b8}\x{2bb}-\x{2c1}\x{2d0}\x{2d1}\x{2e0}-\x{2e4}\x{2ee}\x{370}-\x{373}\x{376}\x{377}\x{37a}-\x{37d}\x{37f}\x{386}\x{388}-\x{38a}\x{38c}\x{38e}-\x{3a1}\x{3a3}-\x{3f5}\x{3f7}-\x{482}\x{48a}-\x{52f}\x{531}-\x{556}\x{559}-\x{55f}\x{561}-\x{587}\x{589}\x{903}-\x{939}\x{93b}\x{93d}-\x{940}\x{949}-\x{94c}\x{94e}-\x{950}\x{958}-\x{961}\x{964}-\x{980}\x{982}\x{983}\x{985}-\x{98c}\x{98f}\x{990}\x{993}-\x{9a8}\x{9aa}-\x{9b0}\x{9b2}\x{9b6}-\x{9b9}\x{9bd}-\x{9c0}\x{9c7}\x{9c8}\x{9cb}\x{9cc}\x{9ce}\x{9d7}\x{9dc}\x{9dd}\x{9df}-\x{9e1}\x{9e6}-\x{9f1}\x{9f4}-\x{9fa}\x{a03}\x{a05}-\x{a0a}\x{a0f}\x{a10}\x{a13}-\x{a28}\x{a2a}-\x{a30}\x{a32}\x{a33}\x{a35}\x{a36}\x{a38}\x{a39}\x{a3e}-\x{a40}\x{a59}-\x{a5c}\x{a5e}\x{a66}-\x{a6f}\x{a72}-\x{a74}\x{a83}\x{a85}-\x{a8d}\x{a8f}-\x{a91}\x{a93}-\x{aa8}\x{aaa}-\x{ab0}\x{ab2}\x{ab3}\x{ab5}-\x{ab9}\x{abd}-\x{ac0}\x{ac9}\x{acb}\x{acc}\x{ad0}\x{ae0}\x{ae1}\x{ae6}-\x{af0}\x{af9}\x{b02}\x{b03}\x{b05}-\x{b0c}\x{b0f}\x{b10}\x{b13}-\x{b28}\x{b2a}-\x{b30}\x{b32}\x{b33}\x{b35}-\x{b39}\x{b3d}\x{b3e}\x{b40}\x{b47}\x{b48}\x{b4b}\x{b4c}\x{b57}\x{b5c}\x{b5d}\x{b5f}-\x{b61}\x{b66}-\x{b77}\x{b83}\x{b85}-\x{b8a}\x{b8e}-\x{b90}\x{b92}-\x{b95}\x{b99}\x{b9a}\x{b9c}\x{b9e}\x{b9f}\x{ba3}\x{ba4}\x{ba8}-\x{baa}\x{bae}-\x{bb9}\x{bbe}\x{bbf}\x{bc1}\x{bc2}\x{bc6}-\x{bc8}\x{bca}-\x{bcc}\x{bd0}\x{bd7}\x{be6}-\x{bf2}\x{c01}-\x{c03}\x{c05}-\x{c0c}\x{c0e}-\x{c10}\x{c12}-\x{c28}\x{c2a}-\x{c39}\x{c3d}\x{c41}-\x{c44}\x{c58}-\x{c5a}\x{c60}\x{c61}\x{c66}-\x{c6f}\x{c7f}\x{c82}\x{c83}\x{c85}-\x{c8c}\x{c8e}-\x{c90}\x{c92}-\x{ca8}\x{caa}-\x{cb3}\x{cb5}-\x{cb9}\x{cbd}-\x{cc4}\x{cc6}-\x{cc8}\x{cca}\x{ccb}\x{cd5}\x{cd6}\x{cde}\x{ce0}\x{ce1}\x{ce6}-\x{cef}\x{cf1}\x{cf2}\x{d02}\x{d03}\x{d05}-\x{d0c}\x{d0e}-\x{d10}\x{d12}-\x{d3a}\x{d3d}-\x{d40}\x{d46}-\x{d48}\x{d4a}-\x{d4c}\x{d4e}\x{d57}\x{d5f}-\x{d61}\x{d66}-\x{d75}\x{d79}-\x{d7f}\x{d82}\x{d83}\x{d85}-\x{d96}\x{d9a}-\x{db1}\x{db3}-\x{dbb}\x{dbd}\x{dc0}-\x{dc6}\x{dcf}-\x{dd1}\x{dd8}-\x{ddf}\x{de6}-\x{def}\x{df2}-\x{df4}\x{e01}-\x{e30}\x{e32}\x{e33}\x{e40}-\x{e46}\x{e4f}-\x{e5b}\x{e81}\x{e82}\x{e84}\x{e87}\x{e88}\x{e8a}\x{e8d}\x{e94}-\x{e97}\x{e99}-\x{e9f}\x{ea1}-\x{ea3}\x{ea5}\x{ea7}\x{eaa}\x{eab}\x{ead}-\x{eb0}\x{eb2}\x{eb3}\x{ebd}\x{ec0}-\x{ec4}\x{ec6}\x{ed0}-\x{ed9}\x{edc}-\x{edf}\x{f00}-\x{f17}\x{f1a}-\x{f34}\x{f36}\x{f38}\x{f3e}-\x{f47}\x{f49}-\x{f6c}\x{f7f}\x{f85}\x{f88}-\x{f8c}\x{fbe}-\x{fc5}\x{fc7}-\x{fcc}\x{fce}-\x{fda}\x{1000}-\x{102c}\x{1031}\x{1038}\x{103b}\x{103c}\x{103f}-\x{1057}\x{105a}-\x{105d}\x{1061}-\x{1070}\x{1075}-\x{1081}\x{1083}\x{1084}\x{1087}-\x{108c}\x{108e}-\x{109c}\x{109e}-\x{10c5}\x{10c7}\x{10cd}\x{10d0}-\x{1248}\x{124a}-\x{124d}\x{1250}-\x{1256}\x{1258}\x{125a}-\x{125d}\x{1260}-\x{1288}\x{128a}-\x{128d}\x{1290}-\x{12b0}\x{12b2}-\x{12b5}\x{12b8}-\x{12be}\x{12c0}\x{12c2}-\x{12c5}\x{12c8}-\x{12d6}\x{12d8}-\x{1310}\x{1312}-\x{1315}\x{1318}-\x{135a}\x{1360}-\x{137c}\x{1380}-\x{138f}\x{13a0}-\x{13f5}\x{13f8}-\x{13fd}\x{1401}-\x{167f}\x{1681}-\x{169a}\x{16a0}-\x{16f8}\x{1700}-\x{170c}\x{170e}-\x{1711}\x{1720}-\x{1731}\x{1735}\x{1736}\x{1740}-\x{1751}\x{1760}-\x{176c}\x{176e}-\x{1770}\x{1780}-\x{17b3}\x{17b6}\x{17be}-\x{17c5}\x{17c7}\x{17c8}\x{17d4}-\x{17da}\x{17dc}\x{17e0}-\x{17e9}\x{1810}-\x{1819}\x{1820}-\x{1877}\x{1880}-\x{18a8}\x{18aa}\x{18b0}-\x{18f5}\x{1900}-\x{191e}\x{1923}-\x{1926}\x{1929}-\x{192b}\x{1930}\x{1931}\x{1933}-\x{1938}\x{1946}-\x{196d}\x{1970}-\x{1974}\x{1980}-\x{19ab}\x{19b0}-\x{19c9}\x{19d0}-\x{19da}\x{1a00}-\x{1a16}\x{1a19}\x{1a1a}\x{1a1e}-\x{1a55}\x{1a57}\x{1a61}\x{1a63}\x{1a64}\x{1a6d}-\x{1a72}\x{1a80}-\x{1a89}\x{1a90}-\x{1a99}\x{1aa0}-\x{1aad}\x{1b04}-\x{1b33}\x{1b35}\x{1b3b}\x{1b3d}-\x{1b41}\x{1b43}-\x{1b4b}\x{1b50}-\x{1b6a}\x{1b74}-\x{1b7c}\x{1b82}-\x{1ba1}\x{1ba6}\x{1ba7}\x{1baa}\x{1bae}-\x{1be5}\x{1be7}\x{1bea}-\x{1bec}\x{1bee}\x{1bf2}\x{1bf3}\x{1bfc}-\x{1c2b}\x{1c34}\x{1c35}\x{1c3b}-\x{1c49}\x{1c4d}-\x{1c7f}\x{1cc0}-\x{1cc7}\x{1cd3}\x{1ce1}\x{1ce9}-\x{1cec}\x{1cee}-\x{1cf3}\x{1cf5}\x{1cf6}\x{1d00}-\x{1dbf}\x{1e00}-\x{1f15}\x{1f18}-\x{1f1d}\x{1f20}-\x{1f45}\x{1f48}-\x{1f4d}\x{1f50}-\x{1f57}\x{1f59}\x{1f5b}\x{1f5d}\x{1f5f}-\x{1f7d}\x{1f80}-\x{1fb4}\x{1fb6}-\x{1fbc}\x{1fbe}\x{1fc2}-\x{1fc4}\x{1fc6}-\x{1fcc}\x{1fd0}-\x{1fd3}\x{1fd6}-\x{1fdb}\x{1fe0}-\x{1fec}\x{1ff2}-\x{1ff4}\x{1ff6}-\x{1ffc}\x{200e}\x{2071}\x{207f}\x{2090}-\x{209c}\x{2102}\x{2107}\x{210a}-\x{2113}\x{2115}\x{2119}-\x{211d}\x{2124}\x{2126}\x{2128}\x{212a}-\x{212d}\x{212f}-\x{2139}\x{213c}-\x{213f}\x{2145}-\x{2149}\x{214e}\x{214f}\x{2160}-\x{2188}\x{2336}-\x{237a}\x{2395}\x{249c}-\x{24e9}\x{26ac}\x{2800}-\x{28ff}\x{2c00}-\x{2c2e}\x{2c30}-\x{2c5e}\x{2c60}-\x{2ce4}\x{2ceb}-\x{2cee}\x{2cf2}\x{2cf3}\x{2d00}-\x{2d25}\x{2d27}\x{2d2d}\x{2d30}-\x{2d67}\x{2d6f}\x{2d70}\x{2d80}-\x{2d96}\x{2da0}-\x{2da6}\x{2da8}-\x{2dae}\x{2db0}-\x{2db6}\x{2db8}-\x{2dbe}\x{2dc0}-\x{2dc6}\x{2dc8}-\x{2dce}\x{2dd0}-\x{2dd6}\x{2dd8}-\x{2dde}\x{3005}-\x{3007}\x{3021}-\x{3029}\x{302e}\x{302f}\x{3031}-\x{3035}\x{3038}-\x{303c}\x{3041}-\x{3096}\x{309d}-\x{309f}\x{30a1}-\x{30fa}\x{30fc}-\x{30ff}\x{3105}-\x{312d}\x{3131}-\x{318e}\x{3190}-\x{31ba}\x{31f0}-\x{321c}\x{3220}-\x{324f}\x{3260}-\x{327b}\x{327f}-\x{32b0}\x{32c0}-\x{32cb}\x{32d0}-\x{32fe}\x{3300}-\x{3376}\x{337b}-\x{33dd}\x{33e0}-\x{33fe}\x{3400}-\x{4db5}\x{4e00}-\x{9fd5}\x{a000}-\x{a48c}\x{a4d0}-\x{a60c}\x{a610}-\x{a62b}\x{a640}-\x{a66e}\x{a680}-\x{a69d}\x{a6a0}-\x{a6ef}\x{a6f2}-\x{a6f7}\x{a722}-\x{a787}\x{a789}-\x{a7ad}\x{a7b0}-\x{a7b7}\x{a7f7}-\x{a801}\x{a803}-\x{a805}\x{a807}-\x{a80a}\x{a80c}-\x{a824}\x{a827}\x{a830}-\x{a837}\x{a840}-\x{a873}\x{a880}-\x{a8c3}\x{a8ce}-\x{a8d9}\x{a8f2}-\x{a8fd}\x{a900}-\x{a925}\x{a92e}-\x{a946}\x{a952}\x{a953}\x{a95f}-\x{a97c}\x{a983}-\x{a9b2}\x{a9b4}\x{a9b5}\x{a9ba}\x{a9bb}\x{a9bd}-\x{a9cd}\x{a9cf}-\x{a9d9}\x{a9de}-\x{a9e4}\x{a9e6}-\x{a9fe}\x{aa00}-\x{aa28}\x{aa2f}\x{aa30}\x{aa33}\x{aa34}\x{aa40}-\x{aa42}\x{aa44}-\x{aa4b}\x{aa4d}\x{aa50}-\x{aa59}\x{aa5c}-\x{aa7b}\x{aa7d}-\x{aaaf}\x{aab1}\x{aab5}\x{aab6}\x{aab9}-\x{aabd}\x{aac0}\x{aac2}\x{aadb}-\x{aaeb}\x{aaee}-\x{aaf5}\x{ab01}-\x{ab06}\x{ab09}-\x{ab0e}\x{ab11}-\x{ab16}\x{ab20}-\x{ab26}\x{ab28}-\x{ab2e}\x{ab30}-\x{ab65}\x{ab70}-\x{abe4}\x{abe6}\x{abe7}\x{abe9}-\x{abec}\x{abf0}-\x{abf9}\x{ac00}-\x{d7a3}\x{d7b0}-\x{d7c6}\x{d7cb}-\x{d7fb}\x{e000}-\x{fa6d}\x{fa70}-\x{fad9}\x{fb00}-\x{fb06}\x{fb13}-\x{fb17}\x{ff21}-\x{ff3a}\x{ff41}-\x{ff5a}\x{ff66}-\x{ffbe}\x{ffc2}-\x{ffc7}\x{ffca}-\x{ffcf}\x{ffd2}-\x{ffd7}\x{ffda}-\x{ffdc}\x{10000}-\x{1000b}\x{1000d}-\x{10026}\x{10028}-\x{1003a}\x{1003c}\x{1003d}\x{1003f}-\x{1004d}\x{10050}-\x{1005d}\x{10080}-\x{100fa}\x{10100}\x{10102}\x{10107}-\x{10133}\x{10137}-\x{1013f}\x{101d0}-\x{101fc}\x{10280}-\x{1029c}\x{102a0}-\x{102d0}\x{10300}-\x{10323}\x{10330}-\x{1034a}\x{10350}-\x{10375}\x{10380}-\x{1039d}\x{1039f}-\x{103c3}\x{103c8}-\x{103d5}\x{10400}-\x{1049d}\x{104a0}-\x{104a9}\x{10500}-\x{10527}\x{10530}-\x{10563}\x{1056f}\x{10600}-\x{10736}\x{10740}-\x{10755}\x{10760}-\x{10767}\x{11000}\x{11002}-\x{11037}\x{11047}-\x{1104d}\x{11066}-\x{1106f}\x{11082}-\x{110b2}\x{110b7}\x{110b8}\x{110bb}-\x{110c1}\x{110d0}-\x{110e8}\x{110f0}-\x{110f9}\x{11103}-\x{11126}\x{1112c}\x{11136}-\x{11143}\x{11150}-\x{11172}\x{11174}-\x{11176}\x{11182}-\x{111b5}\x{111bf}-\x{111c9}\x{111cd}\x{111d0}-\x{111df}\x{111e1}-\x{111f4}\x{11200}-\x{11211}\x{11213}-\x{1122e}\x{11232}\x{11233}\x{11235}\x{11238}-\x{1123d}\x{11280}-\x{11286}\x{11288}\x{1128a}-\x{1128d}\x{1128f}-\x{1129d}\x{1129f}-\x{112a9}\x{112b0}-\x{112de}\x{112e0}-\x{112e2}\x{112f0}-\x{112f9}\x{11302}\x{11303}\x{11305}-\x{1130c}\x{1130f}\x{11310}\x{11313}-\x{11328}\x{1132a}-\x{11330}\x{11332}\x{11333}\x{11335}-\x{11339}\x{1133d}-\x{1133f}\x{11341}-\x{11344}\x{11347}\x{11348}\x{1134b}-\x{1134d}\x{11350}\x{11357}\x{1135d}-\x{11363}\x{11480}-\x{114b2}\x{114b9}\x{114bb}-\x{114be}\x{114c1}\x{114c4}-\x{114c7}\x{114d0}-\x{114d9}\x{11580}-\x{115b1}\x{115b8}-\x{115bb}\x{115be}\x{115c1}-\x{115db}\x{11600}-\x{11632}\x{1163b}\x{1163c}\x{1163e}\x{11641}-\x{11644}\x{11650}-\x{11659}\x{11680}-\x{116aa}\x{116ac}\x{116ae}\x{116af}\x{116b6}\x{116c0}-\x{116c9}\x{11700}-\x{11719}\x{11720}\x{11721}\x{11726}\x{11730}-\x{1173f}\x{118a0}-\x{118f2}\x{118ff}\x{11ac0}-\x{11af8}\x{12000}-\x{12399}\x{12400}-\x{1246e}\x{12470}-\x{12474}\x{12480}-\x{12543}\x{13000}-\x{1342e}\x{14400}-\x{14646}\x{16800}-\x{16a38}\x{16a40}-\x{16a5e}\x{16a60}-\x{16a69}\x{16a6e}\x{16a6f}\x{16ad0}-\x{16aed}\x{16af5}\x{16b00}-\x{16b2f}\x{16b37}-\x{16b45}\x{16b50}-\x{16b59}\x{16b5b}-\x{16b61}\x{16b63}-\x{16b77}\x{16b7d}-\x{16b8f}\x{16f00}-\x{16f44}\x{16f50}-\x{16f7e}\x{16f93}-\x{16f9f}\x{1b000}\x{1b001}\x{1bc00}-\x{1bc6a}\x{1bc70}-\x{1bc7c}\x{1bc80}-\x{1bc88}\x{1bc90}-\x{1bc99}\x{1bc9c}\x{1bc9f}\x{1d000}-\x{1d0f5}\x{1d100}-\x{1d126}\x{1d129}-\x{1d166}\x{1d16a}-\x{1d172}\x{1d183}\x{1d184}\x{1d18c}-\x{1d1a9}\x{1d1ae}-\x{1d1e8}\x{1d360}-\x{1d371}\x{1d400}-\x{1d454}\x{1d456}-\x{1d49c}\x{1d49e}\x{1d49f}\x{1d4a2}\x{1d4a5}\x{1d4a6}\x{1d4a9}-\x{1d4ac}\x{1d4ae}-\x{1d4b9}\x{1d4bb}\x{1d4bd}-\x{1d4c3}\x{1d4c5}-\x{1d505}\x{1d507}-\x{1d50a}\x{1d50d}-\x{1d514}\x{1d516}-\x{1d51c}\x{1d51e}-\x{1d539}\x{1d53b}-\x{1d53e}\x{1d540}-\x{1d544}\x{1d546}\x{1d54a}-\x{1d550}\x{1d552}-\x{1d6a5}\x{1d6a8}-\x{1d6da}\x{1d6dc}-\x{1d714}\x{1d716}-\x{1d74e}\x{1d750}-\x{1d788}\x{1d78a}-\x{1d7c2}\x{1d7c4}-\x{1d7cb}\x{1d800}-\x{1d9ff}\x{1da37}-\x{1da3a}\x{1da6d}-\x{1da74}\x{1da76}-\x{1da83}\x{1da85}-\x{1da8b}\x{1f110}-\x{1f12e}\x{1f130}-\x{1f169}\x{1f170}-\x{1f19a}\x{1f1e6}-\x{1f202}\x{1f210}-\x{1f23a}\x{1f240}-\x{1f248}\x{1f250}\x{1f251}\x{20000}-\x{2a6d6}\x{2a700}-\x{2b734}\x{2b740}-\x{2b81d}\x{2b820}-\x{2cea1}\x{2f800}-\x{2fa1d}\x{f0000}-\x{ffffd}\x{100000}-\x{10fffd}])|([\x{590}\x{5be}\x{5c0}\x{5c3}\x{5c6}\x{5c8}-\x{5ff}\x{7c0}-\x{7ea}\x{7f4}\x{7f5}\x{7fa}-\x{815}\x{81a}\x{824}\x{828}\x{82e}-\x{858}\x{85c}-\x{89f}\x{200f}\x{fb1d}\x{fb1f}-\x{fb28}\x{fb2a}-\x{fb4f}\x{10800}-\x{1091e}\x{10920}-\x{10a00}\x{10a04}\x{10a07}-\x{10a0b}\x{10a10}-\x{10a37}\x{10a3b}-\x{10a3e}\x{10a40}-\x{10ae4}\x{10ae7}-\x{10b38}\x{10b40}-\x{10e5f}\x{10e7f}-\x{10fff}\x{1e800}-\x{1e8cf}\x{1e8d7}-\x{1edff}\x{1ef00}-\x{1efff}\x{608}\x{60b}\x{60d}\x{61b}-\x{64a}\x{66d}-\x{66f}\x{671}-\x{6d5}\x{6e5}\x{6e6}\x{6ee}\x{6ef}\x{6fa}-\x{710}\x{712}-\x{72f}\x{74b}-\x{7a5}\x{7b1}-\x{7bf}\x{8a0}-\x{8e2}\x{fb50}-\x{fd3d}\x{fd40}-\x{fdcf}\x{fdf0}-\x{fdfc}\x{fdfe}\x{fdff}\x{fe70}-\x{fefe}\x{1ee00}-\x{1eeef}\x{1eef2}-\x{1eeff}]))/u';
+       // @codeCoverageIgnoreEnd
+       // @codingStandardsIgnoreEnd
+
+       /**
+        * Get a cached or new language object for a given language code
+        * @param string $code
+        * @return Language
         */
        static function factory( $code ) {
-               if ( !isset( self::$mLangObjCache[$code] ) ) {
-                       if ( count( self::$mLangObjCache ) > 10 ) {
-                               // Don't keep a billion objects around, that's stupid.
-                               self::$mLangObjCache = array();
-                       }
-                       self::$mLangObjCache[$code] = self::newFromCode( $code );
+               global $wgDummyLanguageCodes, $wgLangObjCacheSize;
+
+               if ( isset( $wgDummyLanguageCodes[$code] ) ) {
+                       $code = $wgDummyLanguageCodes[$code];
                }
-               return self::$mLangObjCache[$code];
+
+               // get the language object to process
+               $langObj = isset( self::$mLangObjCache[$code] )
+                       ? self::$mLangObjCache[$code]
+                       : self::newFromCode( $code );
+
+               // merge the language object in to get it up front in the cache
+               self::$mLangObjCache = array_merge( [ $code => $langObj ], self::$mLangObjCache );
+               // get rid of the oldest ones in case we have an overflow
+               self::$mLangObjCache = array_slice( self::$mLangObjCache, 0, $wgLangObjCacheSize, true );
+
+               return $langObj;
        }
 
        /**
         * Create a language object for a given language code
+        * @param string $code
+        * @param bool $fallback Whether we're going through language fallback chain
+        * @throws MWException
+        * @return Language
         */
-       protected static function newFromCode( $code ) {
-               global $IP;
-               static $recursionLevel = 0;
-
-               // Protect against path traversal below
-               if ( !Language::isValidCode( $code ) 
-                       || strcspn( $code, "/\\\000" ) !== strlen( $code ) ) 
-               {
+       protected static function newFromCode( $code, $fallback = false ) {
+               if ( !self::isValidCode( $code ) ) {
                        throw new MWException( "Invalid language code \"$code\"" );
                }
 
-               if ( $code == 'en' ) {
-                       $class = 'Language';
-               } else {
-                       $class = 'Language' . str_replace( '-', '_', ucfirst( $code ) );
-                       // Preload base classes to work around APC/PHP5 bug
-                       if ( file_exists( "$IP/languages/classes/$class.deps.php" ) ) {
-                               include_once( "$IP/languages/classes/$class.deps.php" );
+               if ( !self::isValidBuiltInCode( $code ) ) {
+                       // It's not possible to customise this code with class files, so
+                       // just return a Language object. This is to support uselang= hacks.
+                       $lang = new Language;
+                       $lang->setCode( $code );
+                       return $lang;
+               }
+
+               // Check if there is a language class for the code
+               $class = self::classFromCode( $code, $fallback );
+               if ( class_exists( $class ) ) {
+                       $lang = new $class;
+                       return $lang;
+               }
+
+               // Keep trying the fallback list until we find an existing class
+               $fallbacks = self::getFallbacksFor( $code );
+               foreach ( $fallbacks as $fallbackCode ) {
+                       if ( !self::isValidBuiltInCode( $fallbackCode ) ) {
+                               throw new MWException( "Invalid fallback '$fallbackCode' in fallback sequence for '$code'" );
                        }
-                       if ( file_exists( "$IP/languages/classes/$class.php" ) ) {
-                               include_once( "$IP/languages/classes/$class.php" );
+
+                       $class = self::classFromCode( $fallbackCode );
+                       if ( class_exists( $class ) ) {
+                               $lang = new $class;
+                               $lang->setCode( $code );
+                               return $lang;
                        }
                }
 
-               if ( $recursionLevel > 5 ) {
-                       throw new MWException( "Language fallback loop detected when creating class $class\n" );
+               throw new MWException( "Invalid fallback sequence for language '$code'" );
+       }
+
+       /**
+        * Checks whether any localisation is available for that language tag
+        * in MediaWiki (MessagesXx.php exists).
+        *
+        * @param string $code Language tag (in lower case)
+        * @return bool Whether language is supported
+        * @since 1.21
+        */
+       public static function isSupportedLanguage( $code ) {
+               if ( !self::isValidBuiltInCode( $code ) ) {
+                       return false;
                }
 
-               if ( !class_exists( $class ) ) {
-                       $fallback = Language::getFallbackFor( $code );
-                       ++$recursionLevel;
-                       $lang = Language::newFromCode( $fallback );
-                       --$recursionLevel;
-                       $lang->setCode( $code );
-               } else {
-                       $lang = new $class;
+               if ( $code === 'qqq' ) {
+                       return false;
                }
-               return $lang;
+
+               return is_readable( self::getMessagesFileName( $code ) ) ||
+                       is_readable( self::getJsonMessagesFileName( $code ) );
+       }
+
+       /**
+        * Returns true if a language code string is a well-formed language tag
+        * according to RFC 5646.
+        * This function only checks well-formedness; it doesn't check that
+        * language, script or variant codes actually exist in the repositories.
+        *
+        * Based on regexes by Mark Davis of the Unicode Consortium:
+        * http://unicode.org/repos/cldr/trunk/tools/java/org/unicode/cldr/util/data/langtagRegex.txt
+        *
+        * @param string $code
+        * @param bool $lenient Whether to allow '_' as separator. The default is only '-'.
+        *
+        * @return bool
+        * @since 1.21
+        */
+       public static function isWellFormedLanguageTag( $code, $lenient = false ) {
+               $alpha = '[a-z]';
+               $digit = '[0-9]';
+               $alphanum = '[a-z0-9]';
+               $x = 'x'; # private use singleton
+               $singleton = '[a-wy-z]'; # other singleton
+               $s = $lenient ? '[-_]' : '-';
+
+               $language = "$alpha{2,8}|$alpha{2,3}$s$alpha{3}";
+               $script = "$alpha{4}"; # ISO 15924
+               $region = "(?:$alpha{2}|$digit{3})"; # ISO 3166-1 alpha-2 or UN M.49
+               $variant = "(?:$alphanum{5,8}|$digit$alphanum{3})";
+               $extension = "$singleton(?:$s$alphanum{2,8})+";
+               $privateUse = "$x(?:$s$alphanum{1,8})+";
+
+               # Define certain grandfathered codes, since otherwise the regex is pretty useless.
+               # Since these are limited, this is safe even later changes to the registry --
+               # the only oddity is that it might change the type of the tag, and thus
+               # the results from the capturing groups.
+               # https://www.iana.org/assignments/language-subtag-registry
+
+               $grandfathered = "en{$s}GB{$s}oed"
+                       . "|i{$s}(?:ami|bnn|default|enochian|hak|klingon|lux|mingo|navajo|pwn|tao|tay|tsu)"
+                       . "|no{$s}(?:bok|nyn)"
+                       . "|sgn{$s}(?:BE{$s}(?:fr|nl)|CH{$s}de)"
+                       . "|zh{$s}min{$s}nan";
+
+               $variantList = "$variant(?:$s$variant)*";
+               $extensionList = "$extension(?:$s$extension)*";
+
+               $langtag = "(?:($language)"
+                       . "(?:$s$script)?"
+                       . "(?:$s$region)?"
+                       . "(?:$s$variantList)?"
+                       . "(?:$s$extensionList)?"
+                       . "(?:$s$privateUse)?)";
+
+               # The final breakdown, with capturing groups for each of these components
+               # The variants, extensions, grandfathered, and private-use may have interior '-'
+
+               $root = "^(?:$langtag|$privateUse|$grandfathered)$";
+
+               return (bool)preg_match( "/$root/", strtolower( $code ) );
        }
 
        /**
-        * Returns true if a language code string is of a valid form, whether or 
-        * not it exists.
+        * Returns true if a language code string is of a valid form, whether or
+        * not it exists. This includes codes which are used solely for
+        * customisation via the MediaWiki namespace.
+        *
+        * @param string $code
+        *
+        * @return bool
         */
        public static function isValidCode( $code ) {
-               return strcspn( $code, "/\\\000" ) === strlen( $code );
+               static $cache = [];
+               if ( !isset( $cache[$code] ) ) {
+                       // People think language codes are html safe, so enforce it.
+                       // Ideally we should only allow a-zA-Z0-9-
+                       // but, .+ and other chars are often used for {{int:}} hacks
+                       // see bugs T39564, T39587, T38938
+                       $cache[$code] =
+                               // Protect against path traversal
+                               strcspn( $code, ":/\\\000&<>'\"" ) === strlen( $code )
+                               && !preg_match( MediaWikiTitleCodec::getTitleInvalidRegex(), $code );
+               }
+               return $cache[$code];
+       }
+
+       /**
+        * Returns true if a language code is of a valid form for the purposes of
+        * internal customisation of MediaWiki, via Messages*.php or *.json.
+        *
+        * @param string $code
+        *
+        * @throws MWException
+        * @since 1.18
+        * @return bool
+        */
+       public static function isValidBuiltInCode( $code ) {
+               if ( !is_string( $code ) ) {
+                       if ( is_object( $code ) ) {
+                               $addmsg = " of class " . get_class( $code );
+                       } else {
+                               $addmsg = '';
+                       }
+                       $type = gettype( $code );
+                       throw new MWException( __METHOD__ . " must be passed a string, $type given$addmsg" );
+               }
+
+               return (bool)preg_match( '/^[a-z0-9-]{2,}$/', $code );
+       }
+
+       /**
+        * Returns true if a language code is an IETF tag known to MediaWiki.
+        *
+        * @param string $tag
+        *
+        * @since 1.21
+        * @return bool
+        */
+       public static function isKnownLanguageTag( $tag ) {
+               // Quick escape for invalid input to avoid exceptions down the line
+               // when code tries to process tags which are not valid at all.
+               if ( !self::isValidBuiltInCode( $tag ) ) {
+                       return false;
+               }
+
+               if ( isset( MediaWiki\Languages\Data\Names::$names[$tag] )
+                       || self::fetchLanguageName( $tag, $tag ) !== ''
+               ) {
+                       return true;
+               }
+
+               return false;
        }
 
        /**
         * Get the LocalisationCache instance
+        *
+        * @return LocalisationCache
         */
        public static function getLocalisationCache() {
                if ( is_null( self::$dataCache ) ) {
@@ -210,10 +415,10 @@ class Language {
        function __construct() {
                $this->mConverter = new FakeConverter( $this );
                // Set the code to the name of the descendant
-               if ( get_class( $this ) == 'Language' ) {
+               if ( static::class === 'Language' ) {
                        $this->mCode = 'en';
                } else {
-                       $this->mCode = str_replace( '_', '-', strtolower( substr( get_class( $this ), 8 ) ) );
+                       $this->mCode = str_replace( '_', '-', strtolower( substr( static::class, 8 ) ) );
                }
                self::getLocalisationCache();
        }
@@ -231,44 +436,40 @@ class Language {
         * Hook which will be called if this is the content language.
         * Descendants can use this to register hook functions or modify globals
         */
-       function initContLang() { }
+       function initContLang() {
+       }
 
        /**
-        * @deprecated Use User::getDefaultOptions()
         * @return array
+        * @since 1.19
         */
-       function getDefaultUserOptions() {
-               wfDeprecated( __METHOD__ );
-               return User::getDefaultOptions();
-       }
-
-       function getFallbackLanguageCode() {
-               if ( $this->mCode === 'en' ) {
-                       return false;
-               } else {
-                       return self::$dataCache->getItem( $this->mCode, 'fallback' );
-               }
+       public function getFallbackLanguages() {
+               return self::getFallbacksFor( $this->mCode );
        }
 
        /**
         * Exports $wgBookstoreListEn
         * @return array
         */
-       function getBookstoreList() {
+       public function getBookstoreList() {
                return self::$dataCache->getItem( $this->mCode, 'bookstoreList' );
        }
 
        /**
+        * Returns an array of localised namespaces indexed by their numbers. If the namespace is not
+        * available in localised form, it will be included in English.
+        *
         * @return array
         */
-       function getNamespaces() {
+       public function getNamespaces() {
                if ( is_null( $this->namespaceNames ) ) {
                        global $wgMetaNamespace, $wgMetaNamespaceTalk, $wgExtraNamespaces;
 
-                       $this->namespaceNames = self::$dataCache->getItem( $this->mCode, 'namespaceNames' );
                        $validNamespaces = MWNamespace::getCanonicalNamespaces();
 
-                       $this->namespaceNames = $wgExtraNamespaces + $this->namespaceNames + $validNamespaces;
+                       $this->namespaceNames = $wgExtraNamespaces +
+                               self::$dataCache->getItem( $this->mCode, 'namespaceNames' );
+                       $this->namespaceNames += $validNamespaces;
 
                        $this->namespaceNames[NS_PROJECT] = $wgMetaNamespace;
                        if ( $wgMetaNamespaceTalk ) {
@@ -278,9 +479,9 @@ class Language {
                                $this->namespaceNames[NS_PROJECT_TALK] =
                                        $this->fixVariableInNamespace( $talk );
                        }
-                       
+
                        # Sometimes a language will be localised but not actually exist on this wiki.
-                       foreach( $this->namespaceNames as $key => $text ) {
+                       foreach ( $this->namespaceNames as $key => $text ) {
                                if ( !isset( $validNamespaces[$key] ) ) {
                                        unset( $this->namespaceNames[$key] );
                                }
@@ -289,19 +490,38 @@ class Language {
                        # The above mixing may leave namespaces out of canonical order.
                        # Re-order by namespace ID number...
                        ksort( $this->namespaceNames );
+
+                       Hooks::run( 'LanguageGetNamespaces', [ &$this->namespaceNames ] );
                }
+
                return $this->namespaceNames;
        }
 
        /**
-        * A convenience function that returns the same thing as
-        * getNamespaces() except with the array values changed to ' '
-        * where it found '_', useful for producing output to be displayed
-        * e.g. in <select> forms.
+        * Arbitrarily set all of the namespace names at once. Mainly used for testing
+        * @param array $namespaces Array of namespaces (id => name)
+        */
+       public function setNamespaces( array $namespaces ) {
+               $this->namespaceNames = $namespaces;
+               $this->mNamespaceIds = null;
+       }
+
+       /**
+        * Resets all of the namespace caches. Mainly used for testing
+        */
+       public function resetNamespaces() {
+               $this->namespaceNames = null;
+               $this->mNamespaceIds = null;
+               $this->namespaceAliases = null;
+       }
+
+       /**
+        * A convenience function that returns getNamespaces() with spaces instead of underscores
+        * in values. Useful for producing output to be displayed e.g. in `<select>` forms.
         *
         * @return array
         */
-       function getFormattedNamespaces() {
+       public function getFormattedNamespaces() {
                $ns = $this->getNamespaces();
                foreach ( $ns as $k => $v ) {
                        $ns[$k] = strtr( $v, '_', ' ' );
@@ -311,15 +531,16 @@ class Language {
 
        /**
         * Get a namespace value by key
+        *
         * <code>
         * $mw_ns = $wgContLang->getNsText( NS_MEDIAWIKI );
         * echo $mw_ns; // prints 'MediaWiki'
         * </code>
         *
-        * @param $index Int: the array key of the namespace to return
-        * @return mixed, string if the namespace value exists, otherwise false
+        * @param int $index The array key of the namespace to return
+        * @return string|bool String if the namespace value exists, otherwise false
         */
-       function getNsText( $index ) {
+       public function getNsText( $index ) {
                $ns = $this->getNamespaces();
                return isset( $ns[$index] ) ? $ns[$index] : false;
        }
@@ -329,20 +550,65 @@ class Language {
         * getNsText() except with '_' changed to ' ', useful for
         * producing output.
         *
-        * @return array
+        * <code>
+        * $mw_ns = $wgContLang->getFormattedNsText( NS_MEDIAWIKI_TALK );
+        * echo $mw_ns; // prints 'MediaWiki talk'
+        * </code>
+        *
+        * @param int $index The array key of the namespace to return
+        * @return string Namespace name without underscores (empty string if namespace does not exist)
         */
-       function getFormattedNsText( $index ) {
+       public function getFormattedNsText( $index ) {
                $ns = $this->getNsText( $index );
                return strtr( $ns, '_', ' ' );
        }
 
+       /**
+        * Returns gender-dependent namespace alias if available.
+        * See https://www.mediawiki.org/wiki/Manual:$wgExtraGenderNamespaces
+        * @param int $index Namespace index
+        * @param string $gender Gender key (male, female... )
+        * @return string
+        * @since 1.18
+        */
+       public function getGenderNsText( $index, $gender ) {
+               global $wgExtraGenderNamespaces;
+
+               $ns = $wgExtraGenderNamespaces +
+                       (array)self::$dataCache->getItem( $this->mCode, 'namespaceGenderAliases' );
+
+               return isset( $ns[$index][$gender] ) ? $ns[$index][$gender] : $this->getNsText( $index );
+       }
+
+       /**
+        * Whether this language uses gender-dependent namespace aliases.
+        * See https://www.mediawiki.org/wiki/Manual:$wgExtraGenderNamespaces
+        * @return bool
+        * @since 1.18
+        */
+       public function needsGenderDistinction() {
+               global $wgExtraGenderNamespaces, $wgExtraNamespaces;
+               if ( count( $wgExtraGenderNamespaces ) > 0 ) {
+                       // $wgExtraGenderNamespaces overrides everything
+                       return true;
+               } elseif ( isset( $wgExtraNamespaces[NS_USER] ) && isset( $wgExtraNamespaces[NS_USER_TALK] ) ) {
+                       /// @todo There may be other gender namespace than NS_USER & NS_USER_TALK in the future
+                       // $wgExtraNamespaces overrides any gender aliases specified in i18n files
+                       return false;
+               } else {
+                       // Check what is in i18n files
+                       $aliases = self::$dataCache->getItem( $this->mCode, 'namespaceGenderAliases' );
+                       return count( $aliases ) > 0;
+               }
+       }
+
        /**
         * Get a namespace key by value, case insensitive.
         * Only matches namespace names for the current language, not the
         * canonical ones defined in Namespace.php.
         *
-        * @param $text String
-        * @return mixed An integer if $text is a valid value otherwise false
+        * @param string $text
+        * @return int|bool An integer if $text is a valid value otherwise false
         */
        function getLocalNsIndex( $text ) {
                $lctext = $this->lc( $text );
@@ -350,11 +616,14 @@ class Language {
                return isset( $ids[$lctext] ) ? $ids[$lctext] : false;
        }
 
-       function getNamespaceAliases() {
+       /**
+        * @return array
+        */
+       public function getNamespaceAliases() {
                if ( is_null( $this->namespaceAliases ) ) {
                        $aliases = self::$dataCache->getItem( $this->mCode, 'namespaceAliases' );
                        if ( !$aliases ) {
-                               $aliases = array();
+                               $aliases = [];
                        } else {
                                foreach ( $aliases as $name => $index ) {
                                        if ( $index === NS_PROJECT_TALK ) {
@@ -364,19 +633,44 @@ class Language {
                                        }
                                }
                        }
-                       $this->namespaceAliases = $aliases;
+
+                       global $wgExtraGenderNamespaces;
+                       $genders = $wgExtraGenderNamespaces +
+                               (array)self::$dataCache->getItem( $this->mCode, 'namespaceGenderAliases' );
+                       foreach ( $genders as $index => $forms ) {
+                               foreach ( $forms as $alias ) {
+                                       $aliases[$alias] = $index;
+                               }
+                       }
+
+                       # Also add converted namespace names as aliases, to avoid confusion.
+                       $convertedNames = [];
+                       foreach ( $this->getVariants() as $variant ) {
+                               if ( $variant === $this->mCode ) {
+                                       continue;
+                               }
+                               foreach ( $this->getNamespaces() as $ns => $_ ) {
+                                       $convertedNames[$this->getConverter()->convertNamespace( $ns, $variant )] = $ns;
+                               }
+                       }
+
+                       $this->namespaceAliases = $aliases + $convertedNames;
                }
+
                return $this->namespaceAliases;
        }
 
-       function getNamespaceIds() {
+       /**
+        * @return array
+        */
+       public function getNamespaceIds() {
                if ( is_null( $this->mNamespaceIds ) ) {
                        global $wgNamespaceAliases;
                        # Put namespace names and aliases into a hashtable.
                        # If this is too slow, then we should arrange it so that it is done
                        # before caching. The catch is that at pre-cache time, the above
                        # class-specific fixup hasn't been done.
-                       $this->mNamespaceIds = array();
+                       $this->mNamespaceIds = [];
                        foreach ( $this->getNamespaces() as $index => $name ) {
                                $this->mNamespaceIds[$this->lc( $name )] = $index;
                        }
@@ -392,17 +686,17 @@ class Language {
                return $this->mNamespaceIds;
        }
 
-
        /**
         * Get a namespace key by value, case insensitive.  Canonical namespace
         * names override custom ones defined for the current language.
         *
-        * @param $text String
-        * @return mixed An integer if $text is a valid value otherwise false
+        * @param string $text
+        * @return int|bool An integer if $text is a valid value otherwise false
         */
-       function getNsIndex( $text ) {
+       public function getNsIndex( $text ) {
                $lctext = $this->lc( $text );
-               if ( ( $ns = MWNamespace::getCanonicalIndex( $lctext ) ) !== null ) {
+               $ns = MWNamespace::getCanonicalIndex( $lctext );
+               if ( $ns !== null ) {
                        return $ns;
                }
                $ids = $this->getNamespaceIds();
@@ -412,44 +706,42 @@ class Language {
        /**
         * short names for language variants used for language conversion links.
         *
-        * @param $code String
+        * @param string $code
+        * @param bool $usemsg Use the "variantname-xyz" message if it exists
         * @return string
         */
-       function getVariantname( $code ) {
-               return $this->getMessageFromDB( "variantname-$code" );
-       }
-
-       function specialPage( $name ) {
-               $aliases = $this->getSpecialPageAliases();
-               if ( isset( $aliases[$name][0] ) ) {
-                       $name = $aliases[$name][0];
+       public function getVariantname( $code, $usemsg = true ) {
+               $msg = "variantname-$code";
+               if ( $usemsg && wfMessage( $msg )->exists() ) {
+                       return $this->getMessageFromDB( $msg );
+               }
+               $name = self::fetchLanguageName( $code );
+               if ( $name ) {
+                       return $name; # if it's defined as a language name, show that
+               } else {
+                       # otherwise, output the language code
+                       return $code;
                }
-               return $this->getNsText( NS_SPECIAL ) . ':' . $name;
-       }
-
-       function getQuickbarSettings() {
-               return array(
-                       $this->getMessage( 'qbsettings-none' ),
-                       $this->getMessage( 'qbsettings-fixedleft' ),
-                       $this->getMessage( 'qbsettings-fixedright' ),
-                       $this->getMessage( 'qbsettings-floatingleft' ),
-                       $this->getMessage( 'qbsettings-floatingright' )
-               );
-       }
-
-       function getMathNames() {
-               return self::$dataCache->getItem( $this->mCode, 'mathNames' );
        }
 
-       function getDatePreferences() {
+       /**
+        * @return string[]|bool List of date format preference keys, or false if disabled.
+        */
+       public function getDatePreferences() {
                return self::$dataCache->getItem( $this->mCode, 'datePreferences' );
        }
 
+       /**
+        * @return array
+        */
        function getDateFormats() {
                return self::$dataCache->getItem( $this->mCode, 'dateFormats' );
        }
 
-       function getDefaultDateFormat() {
+       /**
+        * @return array|string
+        */
+       public function getDefaultDateFormat() {
                $df = self::$dataCache->getItem( $this->mCode, 'defaultDateFormat' );
                if ( $df === 'dmy or mdy' ) {
                        global $wgAmericanDates;
@@ -459,175 +751,283 @@ class Language {
                }
        }
 
-       function getDatePreferenceMigrationMap() {
+       /**
+        * @return array
+        */
+       public function getDatePreferenceMigrationMap() {
                return self::$dataCache->getItem( $this->mCode, 'datePreferenceMigrationMap' );
        }
 
+       /**
+        * @param string $image
+        * @return array|null
+        */
        function getImageFile( $image ) {
                return self::$dataCache->getSubitem( $this->mCode, 'imageFiles', $image );
        }
 
-       function getDefaultUserOptionOverrides() {
-               return self::$dataCache->getItem( $this->mCode, 'defaultUserOptionOverrides' );
+       /**
+        * @return array
+        * @since 1.24
+        */
+       public function getImageFiles() {
+               return self::$dataCache->getItem( $this->mCode, 'imageFiles' );
        }
 
-       function getExtraUserToggles() {
-               return self::$dataCache->getItem( $this->mCode, 'extraUserToggles' );
+       /**
+        * @return array
+        */
+       public function getExtraUserToggles() {
+               return (array)self::$dataCache->getItem( $this->mCode, 'extraUserToggles' );
        }
 
+       /**
+        * @param string $tog
+        * @return string
+        */
        function getUserToggle( $tog ) {
                return $this->getMessageFromDB( "tog-$tog" );
        }
 
        /**
-        * Get language names, indexed by code.
-        * If $customisedOnly is true, only returns codes with a messages file
+        * Get an array of language names, indexed by code.
+        * @param null|string $inLanguage Code of language in which to return the names
+        *              Use null for autonyms (native names)
+        * @param string $include One of:
+        *              'all' all available languages
+        *              'mw' only if the language is defined in MediaWiki or wgExtraLanguageNames (default)
+        *              'mwfile' only if the language is in 'mw' *and* has a message file
+        * @return array Language code => language name
+        * @since 1.20
         */
-       public static function getLanguageNames( $customisedOnly = false ) {
-               global $wgLanguageNames, $wgExtraLanguageNames;
-               $allNames = $wgExtraLanguageNames + $wgLanguageNames;
-               if ( !$customisedOnly ) {
-                       return $allNames;
+       public static function fetchLanguageNames( $inLanguage = null, $include = 'mw' ) {
+               $cacheKey = $inLanguage === null ? 'null' : $inLanguage;
+               $cacheKey .= ":$include";
+               if ( self::$languageNameCache === null ) {
+                       self::$languageNameCache = new HashBagOStuff( [ 'maxKeys' => 20 ] );
                }
 
-               global $IP;
-               $names = array();
-               $dir = opendir( "$IP/languages/messages" );
-               while ( false !== ( $file = readdir( $dir ) ) ) {
-                       $code = self::getCodeFromFileName( $file, 'Messages' );
-                       if ( $code && isset( $allNames[$code] ) ) {
-                               $names[$code] = $allNames[$code];
+               $ret = self::$languageNameCache->get( $cacheKey );
+               if ( !$ret ) {
+                       $ret = self::fetchLanguageNamesUncached( $inLanguage, $include );
+                       self::$languageNameCache->set( $cacheKey, $ret );
+               }
+               return $ret;
+       }
+
+       /**
+        * Uncached helper for fetchLanguageNames
+        * @param null|string $inLanguage Code of language in which to return the names
+        *              Use null for autonyms (native names)
+        * @param string $include One of:
+        *              'all' all available languages
+        *              'mw' only if the language is defined in MediaWiki or wgExtraLanguageNames (default)
+        *              'mwfile' only if the language is in 'mw' *and* has a message file
+        * @return array Language code => language name
+        */
+       private static function fetchLanguageNamesUncached( $inLanguage = null, $include = 'mw' ) {
+               global $wgExtraLanguageNames, $wgUsePigLatinVariant;
+
+               // If passed an invalid language code to use, fallback to en
+               if ( $inLanguage !== null && !self::isValidCode( $inLanguage ) ) {
+                       $inLanguage = 'en';
+               }
+
+               $names = [];
+
+               if ( $inLanguage ) {
+                       # TODO: also include when $inLanguage is null, when this code is more efficient
+                       Hooks::run( 'LanguageGetTranslatedLanguageNames', [ &$names, $inLanguage ] );
+               }
+
+               $mwNames = $wgExtraLanguageNames + MediaWiki\Languages\Data\Names::$names;
+               if ( $wgUsePigLatinVariant ) {
+                       // Pig Latin (for variant development)
+                       $mwNames['en-x-piglatin'] = 'Igpay Atinlay';
+               }
+
+               foreach ( $mwNames as $mwCode => $mwName ) {
+                       # - Prefer own MediaWiki native name when not using the hook
+                       # - For other names just add if not added through the hook
+                       if ( $mwCode === $inLanguage || !isset( $names[$mwCode] ) ) {
+                               $names[$mwCode] = $mwName;
                        }
                }
-               closedir( $dir );
-               return $names;
+
+               if ( $include === 'all' ) {
+                       ksort( $names );
+                       return $names;
+               }
+
+               $returnMw = [];
+               $coreCodes = array_keys( $mwNames );
+               foreach ( $coreCodes as $coreCode ) {
+                       $returnMw[$coreCode] = $names[$coreCode];
+               }
+
+               if ( $include === 'mwfile' ) {
+                       $namesMwFile = [];
+                       # We do this using a foreach over the codes instead of a directory
+                       # loop so that messages files in extensions will work correctly.
+                       foreach ( $returnMw as $code => $value ) {
+                               if ( is_readable( self::getMessagesFileName( $code ) )
+                                       || is_readable( self::getJsonMessagesFileName( $code ) )
+                               ) {
+                                       $namesMwFile[$code] = $names[$code];
+                               }
+                       }
+
+                       ksort( $namesMwFile );
+                       return $namesMwFile;
+               }
+
+               ksort( $returnMw );
+               # 'mw' option; default if it's not one of the other two options (all/mwfile)
+               return $returnMw;
+       }
+
+       /**
+        * @param string $code The code of the language for which to get the name
+        * @param null|string $inLanguage Code of language in which to return the name (null for autonyms)
+        * @param string $include 'all', 'mw' or 'mwfile'; see fetchLanguageNames()
+        * @return string Language name or empty
+        * @since 1.20
+        */
+       public static function fetchLanguageName( $code, $inLanguage = null, $include = 'all' ) {
+               $code = strtolower( $code );
+               $array = self::fetchLanguageNames( $inLanguage, $include );
+               return !array_key_exists( $code, $array ) ? '' : $array[$code];
        }
 
        /**
         * Get a message from the MediaWiki namespace.
         *
-        * @param $msg String: message name
+        * @param string $msg Message name
         * @return string
         */
-       function getMessageFromDB( $msg ) {
-               return wfMsgExt( $msg, array( 'parsemag', 'language' => $this ) );
+       public function getMessageFromDB( $msg ) {
+               return $this->msg( $msg )->text();
        }
 
-       function getLanguageName( $code ) {
-               $names = self::getLanguageNames();
-               if ( !array_key_exists( $code, $names ) ) {
-                       return '';
-               }
-               return $names[$code];
+       /**
+        * Get message object in this language. Only for use inside this class.
+        *
+        * @param string $msg Message name
+        * @return Message
+        */
+       protected function msg( $msg ) {
+               return wfMessage( $msg )->inLanguage( $this );
        }
 
-       function getMonthName( $key ) {
+       /**
+        * @param string $key
+        * @return string
+        */
+       public function getMonthName( $key ) {
                return $this->getMessageFromDB( self::$mMonthMsgs[$key - 1] );
        }
 
-       function getMonthNameGen( $key ) {
+       /**
+        * @return array
+        */
+       public function getMonthNamesArray() {
+               $monthNames = [ '' ];
+               for ( $i = 1; $i < 13; $i++ ) {
+                       $monthNames[] = $this->getMonthName( $i );
+               }
+               return $monthNames;
+       }
+
+       /**
+        * @param string $key
+        * @return string
+        */
+       public function getMonthNameGen( $key ) {
                return $this->getMessageFromDB( self::$mMonthGenMsgs[$key - 1] );
        }
 
-       function getMonthAbbreviation( $key ) {
+       /**
+        * @param string $key
+        * @return string
+        */
+       public function getMonthAbbreviation( $key ) {
                return $this->getMessageFromDB( self::$mMonthAbbrevMsgs[$key - 1] );
        }
 
-       function getWeekdayName( $key ) {
+       /**
+        * @return array
+        */
+       public function getMonthAbbreviationsArray() {
+               $monthNames = [ '' ];
+               for ( $i = 1; $i < 13; $i++ ) {
+                       $monthNames[] = $this->getMonthAbbreviation( $i );
+               }
+               return $monthNames;
+       }
+
+       /**
+        * @param string $key
+        * @return string
+        */
+       public function getWeekdayName( $key ) {
                return $this->getMessageFromDB( self::$mWeekdayMsgs[$key - 1] );
        }
 
+       /**
+        * @param string $key
+        * @return string
+        */
        function getWeekdayAbbreviation( $key ) {
                return $this->getMessageFromDB( self::$mWeekdayAbbrevMsgs[$key - 1] );
        }
 
-       function getIranianCalendarMonthName( $key ) {
-               return $this->getMessageFromDB( self::$mIranianCalendarMonthMsgs[$key - 1] );
+       /**
+        * @param string $key
+        * @return string
+        */
+       function getIranianCalendarMonthName( $key ) {
+               return $this->getMessageFromDB( self::$mIranianCalendarMonthMsgs[$key - 1] );
        }
 
+       /**
+        * @param string $key
+        * @return string
+        */
        function getHebrewCalendarMonthName( $key ) {
                return $this->getMessageFromDB( self::$mHebrewCalendarMonthMsgs[$key - 1] );
        }
 
+       /**
+        * @param string $key
+        * @return string
+        */
        function getHebrewCalendarMonthNameGen( $key ) {
                return $this->getMessageFromDB( self::$mHebrewCalendarMonthGenMsgs[$key - 1] );
        }
 
+       /**
+        * @param string $key
+        * @return string
+        */
        function getHijriCalendarMonthName( $key ) {
                return $this->getMessageFromDB( self::$mHijriCalendarMonthMsgs[$key - 1] );
        }
 
        /**
-        * Used by date() and time() to adjust the time output.
-        *
-        * @param $ts Int the time in date('YmdHis') format
-        * @param $tz Mixed: adjust the time by this amount (default false, mean we
-        *            get user timecorrection setting)
-        * @return int
+        * Pass through result from $dateTimeObj->format()
+        * @param DateTime|bool|null &$dateTimeObj
+        * @param string $ts
+        * @param DateTimeZone|bool|null $zone
+        * @param string $code
+        * @return string
         */
-       function userAdjust( $ts, $tz = false ) {
-               global $wgUser, $wgLocalTZoffset;
-
-               if ( $tz === false ) {
-                       $tz = $wgUser->getOption( 'timecorrection' );
-               }
-
-               $data = explode( '|', $tz, 3 );
-
-               if ( $data[0] == 'ZoneInfo' ) {
-                       if ( function_exists( 'timezone_open' ) && @timezone_open( $data[2] ) !== false ) {
-                               $date = date_create( $ts, timezone_open( 'UTC' ) );
-                               date_timezone_set( $date, timezone_open( $data[2] ) );
-                               $date = date_format( $date, 'YmdHis' );
-                               return $date;
-                       }
-                       # Unrecognized timezone, default to 'Offset' with the stored offset.
-                       $data[0] = 'Offset';
-               }
-
-               $minDiff = 0;
-               if ( $data[0] == 'System' || $tz == '' ) {
-                       #  Global offset in minutes.
-                       if ( isset( $wgLocalTZoffset ) ) {
-                               $minDiff = $wgLocalTZoffset;
-                       }
-               } else if ( $data[0] == 'Offset' ) {
-                       $minDiff = intval( $data[1] );
-               } else {
-                       $data = explode( ':', $tz );
-                       if ( count( $data ) == 2 ) {
-                               $data[0] = intval( $data[0] );
-                               $data[1] = intval( $data[1] );
-                               $minDiff = abs( $data[0] ) * 60 + $data[1];
-                               if ( $data[0] < 0 ) {
-                                       $minDiff = -$minDiff;
-                               }
-                       } else {
-                               $minDiff = intval( $data[0] ) * 60;
-                       }
-               }
-
-               # No difference ? Return time unchanged
-               if ( 0 == $minDiff ) {
-                       return $ts;
+       private static function dateTimeObjFormat( &$dateTimeObj, $ts, $zone, $code ) {
+               if ( !$dateTimeObj ) {
+                       $dateTimeObj = DateTime::createFromFormat(
+                               'YmdHis', $ts, $zone ?: new DateTimeZone( 'UTC' )
+                       );
                }
-
-               wfSuppressWarnings(); // E_STRICT system time bitching
-               # Generate an adjusted date; take advantage of the fact that mktime
-               # will normalize out-of-range values so we don't have to split $minDiff
-               # into hours and minutes.
-               $t = mktime( (
-                 (int)substr( $ts, 8, 2 ) ), # Hours
-                 (int)substr( $ts, 10, 2 ) + $minDiff, # Minutes
-                 (int)substr( $ts, 12, 2 ), # Seconds
-                 (int)substr( $ts, 4, 2 ), # Month
-                 (int)substr( $ts, 6, 2 ), # Day
-                 (int)substr( $ts, 0, 4 ) ); # Year
-
-               $date = date( 'YmdHis', $t );
-               wfRestoreWarnings();
-
-               return $date;
+               return $dateTimeObj->format( $code );
        }
 
        /**
@@ -635,8 +1035,8 @@ class Language {
         * internationalisation, a reduced set of format characters, and a better
         * escaping format.
         *
-        * Supported format characters are dDjlNwzWFmMntLoYyaAgGhHiscrU. See the
-        * PHP manual for definitions. There are a number of extensions, which
+        * Supported format characters are dDjlNwzWFmMntLoYyaAgGhHiscrUeIOPTZ. See
+        * the PHP manual for definitions. There are a number of extensions, which
         * start with "x":
         *
         *    xn   Do not translate digits of the next numeric format character
@@ -649,7 +1049,10 @@ class Language {
         *    xij  j (day number) in Iranian calendar
         *    xiF  F (month name) in Iranian calendar
         *    xin  n (month number) in Iranian calendar
+        *    xiy  y (two digit year) in Iranian calendar
         *    xiY  Y (full year) in Iranian calendar
+        *    xit  t (days in month) in Iranian calendar
+        *    xiz  z (day of the year) in Iranian calendar
         *
         *    xjj  j (day number) in Hebrew calendar
         *    xjF  F (month name) in Hebrew calendar
@@ -681,20 +1084,27 @@ class Language {
         * Backslash escaping is also supported.
         *
         * Input timestamp is assumed to be pre-normalized to the desired local
-        * time zone, if any.
+        * time zone, if any. Note that the format characters crUeIOPTZ will assume
+        * $ts is UTC if $zone is not given.
         *
-        * @param $format String
-        * @param $ts String: 14-character timestamp
+        * @param string $format
+        * @param string $ts 14-character timestamp
         *      YYYYMMDDHHMMSS
         *      01234567890123
+        * @param DateTimeZone $zone Timezone of $ts
+        * @param int &$ttl The amount of time (in seconds) the output may be cached for.
+        * Only makes sense if $ts is the current time.
         * @todo handling of "o" format character for Iranian, Hebrew, Hijri & Thai?
+        *
+        * @throws MWException
+        * @return string
         */
-       function sprintfDate( $format, $ts ) {
+       public function sprintfDate( $format, $ts, DateTimeZone $zone = null, &$ttl = 'unused' ) {
                $s = '';
                $raw = false;
                $roman = false;
                $hebrewNum = false;
-               $unix = false;
+               $dateTimeObj = false;
                $rawToggle = false;
                $iranian = false;
                $hebrew = false;
@@ -702,14 +1112,49 @@ class Language {
                $thai = false;
                $minguo = false;
                $tenno = false;
-               for ( $p = 0; $p < strlen( $format ); $p++ ) {
+
+               $usedSecond = false;
+               $usedMinute = false;
+               $usedHour = false;
+               $usedAMPM = false;
+               $usedDay = false;
+               $usedWeek = false;
+               $usedMonth = false;
+               $usedYear = false;
+               $usedISOYear = false;
+               $usedIsLeapYear = false;
+
+               $usedHebrewMonth = false;
+               $usedIranianMonth = false;
+               $usedHijriMonth = false;
+               $usedHebrewYear = false;
+               $usedIranianYear = false;
+               $usedHijriYear = false;
+               $usedTennoYear = false;
+
+               if ( strlen( $ts ) !== 14 ) {
+                       throw new MWException( __METHOD__ . ": The timestamp $ts should have 14 characters" );
+               }
+
+               if ( !ctype_digit( $ts ) ) {
+                       throw new MWException( __METHOD__ . ": The timestamp $ts should be a number" );
+               }
+
+               $formatLength = strlen( $format );
+               for ( $p = 0; $p < $formatLength; $p++ ) {
                        $num = false;
                        $code = $format[$p];
-                       if ( $code == 'x' && $p < strlen( $format ) - 1 ) {
+                       if ( $code == 'x' && $p < $formatLength - 1 ) {
                                $code .= $format[++$p];
                        }
 
-                       if ( ( $code === 'xi' || $code == 'xj' || $code == 'xk' || $code == 'xm' || $code == 'xo' || $code == 'xt' ) && $p < strlen( $format ) - 1 ) {
+                       if ( ( $code === 'xi'
+                                       || $code === 'xj'
+                                       || $code === 'xk'
+                                       || $code === 'xm'
+                                       || $code === 'xo'
+                                       || $code === 'xt' )
+                               && $p < $formatLength - 1 ) {
                                $code .= $format[++$p];
                        }
 
@@ -730,232 +1175,269 @@ class Language {
                                        $hebrewNum = true;
                                        break;
                                case 'xg':
+                                       $usedMonth = true;
                                        $s .= $this->getMonthNameGen( substr( $ts, 4, 2 ) );
                                        break;
                                case 'xjx':
-                                       if ( !$hebrew ) $hebrew = self::tsToHebrew( $ts );
+                                       $usedHebrewMonth = true;
+                                       if ( !$hebrew ) {
+                                               $hebrew = self::tsToHebrew( $ts );
+                                       }
                                        $s .= $this->getHebrewCalendarMonthNameGen( $hebrew[1] );
                                        break;
                                case 'd':
+                                       $usedDay = true;
                                        $num = substr( $ts, 6, 2 );
                                        break;
                                case 'D':
-                                       if ( !$unix ) $unix = wfTimestamp( TS_UNIX, $ts );
-                                       $s .= $this->getWeekdayAbbreviation( gmdate( 'w', $unix ) + 1 );
+                                       $usedDay = true;
+                                       $s .= $this->getWeekdayAbbreviation(
+                                               self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, 'w' ) + 1
+                                       );
                                        break;
                                case 'j':
+                                       $usedDay = true;
                                        $num = intval( substr( $ts, 6, 2 ) );
                                        break;
                                case 'xij':
+                                       $usedDay = true;
                                        if ( !$iranian ) {
                                                $iranian = self::tsToIranian( $ts );
                                        }
                                        $num = $iranian[2];
                                        break;
                                case 'xmj':
+                                       $usedDay = true;
                                        if ( !$hijri ) {
                                                $hijri = self::tsToHijri( $ts );
                                        }
                                        $num = $hijri[2];
                                        break;
                                case 'xjj':
+                                       $usedDay = true;
                                        if ( !$hebrew ) {
                                                $hebrew = self::tsToHebrew( $ts );
                                        }
                                        $num = $hebrew[2];
                                        break;
                                case 'l':
-                                       if ( !$unix ) {
-                                               $unix = wfTimestamp( TS_UNIX, $ts );
-                                       }
-                                       $s .= $this->getWeekdayName( gmdate( 'w', $unix ) + 1 );
-                                       break;
-                               case 'N':
-                                       if ( !$unix ) {
-                                               $unix = wfTimestamp( TS_UNIX, $ts );
-                                       }
-                                       $w = gmdate( 'w', $unix );
-                                       $num = $w ? $w : 7;
-                                       break;
-                               case 'w':
-                                       if ( !$unix ) {
-                                               $unix = wfTimestamp( TS_UNIX, $ts );
-                                       }
-                                       $num = gmdate( 'w', $unix );
-                                       break;
-                               case 'z':
-                                       if ( !$unix ) {
-                                               $unix = wfTimestamp( TS_UNIX, $ts );
-                                       }
-                                       $num = gmdate( 'z', $unix );
-                                       break;
-                               case 'W':
-                                       if ( !$unix ) {
-                                               $unix = wfTimestamp( TS_UNIX, $ts );
-                                       }
-                                       $num = gmdate( 'W', $unix );
+                                       $usedDay = true;
+                                       $s .= $this->getWeekdayName(
+                                               self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, 'w' ) + 1
+                                       );
                                        break;
                                case 'F':
+                                       $usedMonth = true;
                                        $s .= $this->getMonthName( substr( $ts, 4, 2 ) );
                                        break;
                                case 'xiF':
+                                       $usedIranianMonth = true;
                                        if ( !$iranian ) {
                                                $iranian = self::tsToIranian( $ts );
                                        }
                                        $s .= $this->getIranianCalendarMonthName( $iranian[1] );
                                        break;
                                case 'xmF':
+                                       $usedHijriMonth = true;
                                        if ( !$hijri ) {
                                                $hijri = self::tsToHijri( $ts );
                                        }
                                        $s .= $this->getHijriCalendarMonthName( $hijri[1] );
                                        break;
                                case 'xjF':
+                                       $usedHebrewMonth = true;
                                        if ( !$hebrew ) {
                                                $hebrew = self::tsToHebrew( $ts );
                                        }
                                        $s .= $this->getHebrewCalendarMonthName( $hebrew[1] );
                                        break;
                                case 'm':
+                                       $usedMonth = true;
                                        $num = substr( $ts, 4, 2 );
                                        break;
                                case 'M':
+                                       $usedMonth = true;
                                        $s .= $this->getMonthAbbreviation( substr( $ts, 4, 2 ) );
                                        break;
                                case 'n':
+                                       $usedMonth = true;
                                        $num = intval( substr( $ts, 4, 2 ) );
                                        break;
                                case 'xin':
+                                       $usedIranianMonth = true;
                                        if ( !$iranian ) {
                                                $iranian = self::tsToIranian( $ts );
                                        }
                                        $num = $iranian[1];
                                        break;
                                case 'xmn':
+                                       $usedHijriMonth = true;
                                        if ( !$hijri ) {
-                                               $hijri = self::tsToHijri ( $ts );
+                                               $hijri = self::tsToHijri( $ts );
                                        }
                                        $num = $hijri[1];
                                        break;
                                case 'xjn':
+                                       $usedHebrewMonth = true;
                                        if ( !$hebrew ) {
                                                $hebrew = self::tsToHebrew( $ts );
                                        }
                                        $num = $hebrew[1];
                                        break;
-                               case 't':
-                                       if ( !$unix ) {
-                                               $unix = wfTimestamp( TS_UNIX, $ts );
-                                       }
-                                       $num = gmdate( 't', $unix );
-                                       break;
                                case 'xjt':
+                                       $usedHebrewMonth = true;
                                        if ( !$hebrew ) {
                                                $hebrew = self::tsToHebrew( $ts );
                                        }
                                        $num = $hebrew[3];
                                        break;
-                               case 'L':
-                                       if ( !$unix ) {
-                                               $unix = wfTimestamp( TS_UNIX, $ts );
-                                       }
-                                       $num = gmdate( 'L', $unix );
-                                       break;
-                               case 'o':
-                                       if ( !$unix ) {
-                                               $unix = wfTimestamp( TS_UNIX, $ts );
-                                       }
-                                       $num = date( 'o', $unix );
-                                       break;
                                case 'Y':
+                                       $usedYear = true;
                                        $num = substr( $ts, 0, 4 );
                                        break;
                                case 'xiY':
+                                       $usedIranianYear = true;
                                        if ( !$iranian ) {
                                                $iranian = self::tsToIranian( $ts );
                                        }
                                        $num = $iranian[0];
                                        break;
                                case 'xmY':
+                                       $usedHijriYear = true;
                                        if ( !$hijri ) {
                                                $hijri = self::tsToHijri( $ts );
                                        }
                                        $num = $hijri[0];
                                        break;
                                case 'xjY':
+                                       $usedHebrewYear = true;
                                        if ( !$hebrew ) {
                                                $hebrew = self::tsToHebrew( $ts );
                                        }
                                        $num = $hebrew[0];
                                        break;
                                case 'xkY':
+                                       $usedYear = true;
                                        if ( !$thai ) {
                                                $thai = self::tsToYear( $ts, 'thai' );
                                        }
                                        $num = $thai[0];
                                        break;
                                case 'xoY':
+                                       $usedYear = true;
                                        if ( !$minguo ) {
                                                $minguo = self::tsToYear( $ts, 'minguo' );
                                        }
                                        $num = $minguo[0];
                                        break;
                                case 'xtY':
+                                       $usedTennoYear = true;
                                        if ( !$tenno ) {
                                                $tenno = self::tsToYear( $ts, 'tenno' );
                                        }
                                        $num = $tenno[0];
                                        break;
                                case 'y':
+                                       $usedYear = true;
                                        $num = substr( $ts, 2, 2 );
                                        break;
+                               case 'xiy':
+                                       $usedIranianYear = true;
+                                       if ( !$iranian ) {
+                                               $iranian = self::tsToIranian( $ts );
+                                       }
+                                       $num = substr( $iranian[0], -2 );
+                                       break;
+                               case 'xit':
+                                       $usedIranianYear = true;
+                                       if ( !$iranian ) {
+                                               $iranian = self::tsToIranian( $ts );
+                                       }
+                                       $num = self::$IRANIAN_DAYS[$iranian[1] - 1];
+                                       break;
+                               case 'xiz':
+                                       $usedIranianYear = true;
+                                       if ( !$iranian ) {
+                                               $iranian = self::tsToIranian( $ts );
+                                       }
+                                       $num = $iranian[3];
+                                       break;
                                case 'a':
+                                       $usedAMPM = true;
                                        $s .= intval( substr( $ts, 8, 2 ) ) < 12 ? 'am' : 'pm';
                                        break;
                                case 'A':
+                                       $usedAMPM = true;
                                        $s .= intval( substr( $ts, 8, 2 ) ) < 12 ? 'AM' : 'PM';
                                        break;
                                case 'g':
+                                       $usedHour = true;
                                        $h = substr( $ts, 8, 2 );
                                        $num = $h % 12 ? $h % 12 : 12;
                                        break;
                                case 'G':
+                                       $usedHour = true;
                                        $num = intval( substr( $ts, 8, 2 ) );
                                        break;
                                case 'h':
+                                       $usedHour = true;
                                        $h = substr( $ts, 8, 2 );
                                        $num = sprintf( '%02d', $h % 12 ? $h % 12 : 12 );
                                        break;
                                case 'H':
+                                       $usedHour = true;
                                        $num = substr( $ts, 8, 2 );
                                        break;
                                case 'i':
+                                       $usedMinute = true;
                                        $num = substr( $ts, 10, 2 );
                                        break;
                                case 's':
+                                       $usedSecond = true;
                                        $num = substr( $ts, 12, 2 );
                                        break;
                                case 'c':
-                                       if ( !$unix ) {
-                                               $unix = wfTimestamp( TS_UNIX, $ts );
-                                       }
-                                       $s .= gmdate( 'c', $unix );
-                                       break;
                                case 'r':
-                                       if ( !$unix ) {
-                                               $unix = wfTimestamp( TS_UNIX, $ts );
-                                       }
-                                       $s .= gmdate( 'r', $unix );
+                                       $usedSecond = true;
+                                       // fall through
+                               case 'e':
+                               case 'O':
+                               case 'P':
+                               case 'T':
+                                       $s .= self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, $code );
+                                       break;
+                               case 'w':
+                               case 'N':
+                               case 'z':
+                                       $usedDay = true;
+                                       $num = self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, $code );
+                                       break;
+                               case 'W':
+                                       $usedWeek = true;
+                                       $num = self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, $code );
+                                       break;
+                               case 't':
+                                       $usedMonth = true;
+                                       $num = self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, $code );
+                                       break;
+                               case 'L':
+                                       $usedIsLeapYear = true;
+                                       $num = self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, $code );
+                                       break;
+                               case 'o':
+                                       $usedISOYear = true;
+                                       $num = self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, $code );
                                        break;
                                case 'U':
-                                       if ( !$unix ) {
-                                               $unix = wfTimestamp( TS_UNIX, $ts );
-                                       }
-                                       $num = $unix;
+                                       $usedSecond = true;
+                                       // fall through
+                               case 'I':
+                               case 'Z':
+                                       $num = self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, $code );
                                        break;
                                case '\\':
                                        # Backslash escaping
-                                       if ( $p < strlen( $format ) - 1 ) {
+                                       if ( $p < $formatLength - 1 ) {
                                                $s .= $format[++$p];
                                        } else {
                                                $s .= '\\';
@@ -963,7 +1445,7 @@ class Language {
                                        break;
                                case '"':
                                        # Quoted literal
-                                       if ( $p < strlen( $format ) - 1 ) {
+                                       if ( $p < $formatLength - 1 ) {
                                                $endQuote = strpos( $format, '"', $p + 1 );
                                                if ( $endQuote === false ) {
                                                        # No terminating quote, assume literal "
@@ -995,11 +1477,100 @@ class Language {
                                }
                        }
                }
+
+               if ( $ttl === 'unused' ) {
+                       // No need to calculate the TTL, the caller wont use it anyway.
+               } elseif ( $usedSecond ) {
+                       $ttl = 1;
+               } elseif ( $usedMinute ) {
+                       $ttl = 60 - substr( $ts, 12, 2 );
+               } elseif ( $usedHour ) {
+                       $ttl = 3600 - substr( $ts, 10, 2 ) * 60 - substr( $ts, 12, 2 );
+               } elseif ( $usedAMPM ) {
+                       $ttl = 43200 - ( substr( $ts, 8, 2 ) % 12 ) * 3600 -
+                               substr( $ts, 10, 2 ) * 60 - substr( $ts, 12, 2 );
+               } elseif (
+                       $usedDay ||
+                       $usedHebrewMonth ||
+                       $usedIranianMonth ||
+                       $usedHijriMonth ||
+                       $usedHebrewYear ||
+                       $usedIranianYear ||
+                       $usedHijriYear ||
+                       $usedTennoYear
+               ) {
+                       // @todo Someone who understands the non-Gregorian calendars
+                       // should write proper logic for them so that they don't need purged every day.
+                       $ttl = 86400 - substr( $ts, 8, 2 ) * 3600 -
+                               substr( $ts, 10, 2 ) * 60 - substr( $ts, 12, 2 );
+               } else {
+                       $possibleTtls = [];
+                       $timeRemainingInDay = 86400 - substr( $ts, 8, 2 ) * 3600 -
+                               substr( $ts, 10, 2 ) * 60 - substr( $ts, 12, 2 );
+                       if ( $usedWeek ) {
+                               $possibleTtls[] =
+                                       ( 7 - self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, 'N' ) ) * 86400 +
+                                       $timeRemainingInDay;
+                       } elseif ( $usedISOYear ) {
+                               // December 28th falls on the last ISO week of the year, every year.
+                               // The last ISO week of a year can be 52 or 53.
+                               $lastWeekOfISOYear = DateTime::createFromFormat(
+                                       'Ymd',
+                                       substr( $ts, 0, 4 ) . '1228',
+                                       $zone ?: new DateTimeZone( 'UTC' )
+                               )->format( 'W' );
+                               $currentISOWeek = self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, 'W' );
+                               $weeksRemaining = $lastWeekOfISOYear - $currentISOWeek;
+                               $timeRemainingInWeek =
+                                       ( 7 - self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, 'N' ) ) * 86400
+                                       + $timeRemainingInDay;
+                               $possibleTtls[] = $weeksRemaining * 604800 + $timeRemainingInWeek;
+                       }
+
+                       if ( $usedMonth ) {
+                               $possibleTtls[] =
+                                       ( self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, 't' ) -
+                                               substr( $ts, 6, 2 ) ) * 86400
+                                       + $timeRemainingInDay;
+                       } elseif ( $usedYear ) {
+                               $possibleTtls[] =
+                                       ( self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, 'L' ) + 364 -
+                                               self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, 'z' ) ) * 86400
+                                       + $timeRemainingInDay;
+                       } elseif ( $usedIsLeapYear ) {
+                               $year = substr( $ts, 0, 4 );
+                               $timeRemainingInYear =
+                                       ( self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, 'L' ) + 364 -
+                                               self::dateTimeObjFormat( $dateTimeObj, $ts, $zone, 'z' ) ) * 86400
+                                       + $timeRemainingInDay;
+                               $mod = $year % 4;
+                               if ( $mod || ( !( $year % 100 ) && $year % 400 ) ) {
+                                       // this isn't a leap year. see when the next one starts
+                                       $nextCandidate = $year - $mod + 4;
+                                       if ( $nextCandidate % 100 || !( $nextCandidate % 400 ) ) {
+                                               $possibleTtls[] = ( $nextCandidate - $year - 1 ) * 365 * 86400 +
+                                                       $timeRemainingInYear;
+                                       } else {
+                                               $possibleTtls[] = ( $nextCandidate - $year + 3 ) * 365 * 86400 +
+                                                       $timeRemainingInYear;
+                                       }
+                               } else {
+                                       // this is a leap year, so the next year isn't
+                                       $possibleTtls[] = $timeRemainingInYear;
+                               }
+                       }
+
+                       if ( $possibleTtls ) {
+                               $ttl = min( $possibleTtls );
+                       }
+               }
+
                return $s;
        }
 
-       private static $GREG_DAYS = array( 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 );
-       private static $IRANIAN_DAYS = array( 31, 31, 31, 31, 31, 31, 30, 30, 30, 30, 30, 29 );
+       private static $GREG_DAYS = [ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ];
+       private static $IRANIAN_DAYS = [ 31, 31, 31, 31, 31, 31, 30, 30, 30, 30, 30, 29 ];
+
        /**
         * Algorithm by Roozbeh Pournader and Mohammad Toossi to convert
         * Gregorian dates to Iranian dates. Originally written in C, it
@@ -1007,11 +1578,15 @@ class Language {
         * License. Conversion to PHP was performed by Niklas Laxström.
         *
         * Link: http://www.farsiweb.info/jalali/jalali.c
+        *
+        * @param string $ts
+        *
+        * @return int[]
         */
        private static function tsToIranian( $ts ) {
-               $gy = substr( $ts, 0, 4 ) -1600;
-               $gm = substr( $ts, 4, 2 ) -1;
-               $gd = substr( $ts, 6, 2 ) -1;
+               $gy = substr( $ts, 0, 4 ) - 1600;
+               $gm = substr( $ts, 4, 2 ) - 1;
+               $gd = substr( $ts, 6, 2 ) - 1;
 
                # Days passed from the beginning (including leap years)
                $gDayNo = 365 * $gy
@@ -1019,7 +1594,6 @@ class Language {
                        - floor( ( $gy + 99 ) / 100 )
                        + floor( ( $gy + 399 ) / 400 );
 
-
                // Add days of the past months of this year
                for ( $i = 0; $i < $gm; $i++ ) {
                        $gDayNo += self::$GREG_DAYS[$i];
@@ -1031,7 +1605,7 @@ class Language {
                }
 
                // Days passed in current month
-               $gDayNo += $gd;
+               $gDayNo += (int)$gd;
 
                $jDayNo = $gDayNo - 79;
 
@@ -1046,6 +1620,8 @@ class Language {
                        $jDayNo = floor( ( $jDayNo - 1 ) % 365 );
                }
 
+               $jz = $jDayNo;
+
                for ( $i = 0; $i < 11 && $jDayNo >= self::$IRANIAN_DAYS[$i]; $i++ ) {
                        $jDayNo -= self::$IRANIAN_DAYS[$i];
                }
@@ -1053,7 +1629,7 @@ class Language {
                $jm = $i + 1;
                $jd = $jDayNo + 1;
 
-               return array( $jy, $jm, $jd );
+               return [ $jy, $jm, $jd, $jz ];
        }
 
        /**
@@ -1061,7 +1637,11 @@ class Language {
         *
         * Based on a PHP-Nuke block by Sharjeel which is released under GNU/GPL license
         *
-        * @link http://phpnuke.org/modules.php?name=News&file=article&sid=8234&mode=thread&order=0&thold=0
+        * @see https://phpnuke.org/modules.php?name=News&file=article&sid=8234&mode=thread&order=0&thold=0
+        *
+        * @param string $ts
+        *
+        * @return int[]
         */
        private static function tsToHijri( $ts ) {
                $year = substr( $ts, 0, 4 );
@@ -1076,8 +1656,7 @@ class Language {
                if (
                        ( $zy > 1582 ) || ( ( $zy == 1582 ) && ( $zm > 10 ) ) ||
                        ( ( $zy == 1582 ) && ( $zm == 10 ) && ( $zd > 14 ) )
-               )
-               {
+               ) {
                        $zjd = (int)( ( 1461 * ( $zy + 4800 + (int)( ( $zm - 14 ) / 12 ) ) ) / 4 ) +
                                        (int)( ( 367 * ( $zm - 2 - 12 * ( (int)( ( $zm - 14 ) / 12 ) ) ) ) / 12 ) -
                                        (int)( ( 3 * (int)( ( ( $zy + 4900 + (int)( ( $zm - 14 ) / 12 ) ) / 100 ) ) ) / 4 ) +
@@ -1087,16 +1666,18 @@ class Language {
                                                                (int)( ( 275 * $zm ) / 9 ) + $zd + 1729777;
                }
 
-               $zl = $zjd -1948440 + 10632;
+               $zl = $zjd - 1948440 + 10632;
                $zn = (int)( ( $zl - 1 ) / 10631 );
                $zl = $zl - 10631 * $zn + 354;
-               $zj = ( (int)( ( 10985 - $zl ) / 5316 ) ) * ( (int)( ( 50 * $zl ) / 17719 ) ) + ( (int)( $zl / 5670 ) ) * ( (int)( ( 43 * $zl ) / 15238 ) );
-               $zl = $zl - ( (int)( ( 30 - $zj ) / 15 ) ) * ( (int)( ( 17719 * $zj ) / 50 ) ) - ( (int)( $zj / 16 ) ) * ( (int)( ( 15238 * $zj ) / 43 ) ) + 29;
+               $zj = ( (int)( ( 10985 - $zl ) / 5316 ) ) * ( (int)( ( 50 * $zl ) / 17719 ) ) +
+                       ( (int)( $zl / 5670 ) ) * ( (int)( ( 43 * $zl ) / 15238 ) );
+               $zl = $zl - ( (int)( ( 30 - $zj ) / 15 ) ) * ( (int)( ( 17719 * $zj ) / 50 ) ) -
+                       ( (int)( $zj / 16 ) ) * ( (int)( ( 15238 * $zj ) / 43 ) ) + 29;
                $zm = (int)( ( 24 * $zl ) / 709 );
                $zd = $zl - (int)( ( 709 * $zm ) / 24 );
                $zy = 30 * $zn + $zj - 30;
 
-               return array( $zy, $zm, $zd );
+               return [ $zy, $zm, $zd ];
        }
 
        /**
@@ -1109,6 +1690,10 @@ class Language {
         *
         * The months are counted from Tishrei = 1. In a leap year, Adar I is 13
         * and Adar II is 14. In a non-leap year, Adar is 6.
+        *
+        * @param string $ts
+        *
+        * @return int[]
         */
        private static function tsToHebrew( $ts ) {
                # Parse date
@@ -1239,18 +1824,22 @@ class Language {
                        }
                }
 
-               return array( $hebrewYear, $hebrewMonth, $hebrewDay, $days );
+               return [ $hebrewYear, $hebrewMonth, $hebrewDay, $days ];
        }
 
        /**
         * This calculates the Hebrew year start, as days since 1 September.
         * Based on Carl Friedrich Gauss algorithm for finding Easter date.
         * Used for Hebrew date.
+        *
+        * @param int $year
+        *
+        * @return string
         */
        private static function hebrewYearStart( $year ) {
                $a = intval( ( 12 * ( $year - 1 ) + 17 ) % 19 );
                $b = intval( ( $year - 1 ) % 4 );
-               $m = 32.044093161144 + 1.5542417966212 * $a +  $b / 4.0 - 0.0031777940220923 * ( $year - 1 );
+               $m = 32.044093161144 + 1.5542417966212 * $a + $b / 4.0 - 0.0031777940220923 * ( $year - 1 );
                if ( $m < 0 ) {
                        $m--;
                }
@@ -1263,9 +1852,9 @@ class Language {
                $c = intval( ( $Mar + 3 * ( $year - 1 ) + 5 * $b + 5 ) % 7 );
                if ( $c == 0 && $a > 11 && $m >= 0.89772376543210 ) {
                        $Mar++;
-               } else if ( $c == 1 && $a > 6 && $m >= 0.63287037037037 ) {
+               } elseif ( $c == 1 && $a > 6 && $m >= 0.63287037037037 ) {
                        $Mar += 2;
-               } else if ( $c == 2 || $c == 4 || $c == 6 ) {
+               } elseif ( $c == 2 || $c == 4 || $c == 6 ) {
                        $Mar++;
                }
 
@@ -1277,13 +1866,13 @@ class Language {
         * Algorithm to convert Gregorian dates to Thai solar dates,
         * Minguo dates or Minguo dates.
         *
-        * Link: http://en.wikipedia.org/wiki/Thai_solar_calendar
-        *       http://en.wikipedia.org/wiki/Minguo_calendar
-        *       http://en.wikipedia.org/wiki/Japanese_era_name
+        * Link: https://en.wikipedia.org/wiki/Thai_solar_calendar
+        *       https://en.wikipedia.org/wiki/Minguo_calendar
+        *       https://en.wikipedia.org/wiki/Japanese_era_name
         *
-        * @param $ts String: 14-character timestamp
-        * @param $cName String: calender name
-        * @return Array: converted year, month, day
+        * @param string $ts 14-character timestamp
+        * @param string $cName Calender name
+        * @return array Converted year, month, day
         */
        private static function tsToYear( $ts, $cName ) {
                $gy = substr( $ts, 0, 4 );
@@ -1295,17 +1884,20 @@ class Language {
                        # Add 543 years to the Gregorian calendar
                        # Months and days are identical
                        $gy_offset = $gy + 543;
-               } else if ( ( !strcmp( $cName, 'minguo' ) ) || !strcmp( $cName, 'juche' ) ) {
+               } elseif ( ( !strcmp( $cName, 'minguo' ) ) || !strcmp( $cName, 'juche' ) ) {
                        # Minguo dates
                        # Deduct 1911 years from the Gregorian calendar
                        # Months and days are identical
                        $gy_offset = $gy - 1911;
-               } else if ( !strcmp( $cName, 'tenno' ) ) {
+               } elseif ( !strcmp( $cName, 'tenno' ) ) {
                        # Nengō dates up to Meiji period
                        # Deduct years from the Gregorian calendar
                        # depending on the nengo periods
                        # Months and days are identical
-                       if ( ( $gy < 1912 ) || ( ( $gy == 1912 ) && ( $gm < 7 ) ) || ( ( $gy == 1912 ) && ( $gm == 7 ) && ( $gd < 31 ) ) ) {
+                       if ( ( $gy < 1912 )
+                               || ( ( $gy == 1912 ) && ( $gm < 7 ) )
+                               || ( ( $gy == 1912 ) && ( $gm == 7 ) && ( $gd < 31 ) )
+                       ) {
                                # Meiji period
                                $gy_gannen = $gy - 1868 + 1;
                                $gy_offset = $gy_gannen;
@@ -1313,14 +1905,13 @@ class Language {
                                        $gy_offset = '元';
                                }
                                $gy_offset = '明治' . $gy_offset;
-                       } else if (
+                       } elseif (
                                ( ( $gy == 1912 ) && ( $gm == 7 ) && ( $gd == 31 ) ) ||
                                ( ( $gy == 1912 ) && ( $gm >= 8 ) ) ||
                                ( ( $gy > 1912 ) && ( $gy < 1926 ) ) ||
                                ( ( $gy == 1926 ) && ( $gm < 12 ) ) ||
                                ( ( $gy == 1926 ) && ( $gm == 12 ) && ( $gd < 26 ) )
-                       )
-                       {
+                       ) {
                                # Taishō period
                                $gy_gannen = $gy - 1912 + 1;
                                $gy_offset = $gy_gannen;
@@ -1328,12 +1919,11 @@ class Language {
                                        $gy_offset = '元';
                                }
                                $gy_offset = '大正' . $gy_offset;
-                       } else if (
+                       } elseif (
                                ( ( $gy == 1926 ) && ( $gm == 12 ) && ( $gd >= 26 ) ) ||
                                ( ( $gy > 1926 ) && ( $gy < 1989 ) ) ||
                                ( ( $gy == 1989 ) && ( $gm == 1 ) && ( $gd < 8 ) )
-                       )
-                       {
+                       ) {
                                # Shōwa period
                                $gy_gannen = $gy - 1926 + 1;
                                $gy_offset = $gy_gannen;
@@ -1354,92 +1944,218 @@ class Language {
                        $gy_offset = $gy;
                }
 
-               return array( $gy_offset, $gm, $gd );
+               return [ $gy_offset, $gm, $gd ];
+       }
+
+       /**
+        * Gets directionality of the first strongly directional codepoint, for embedBidi()
+        *
+        * This is the rule the BIDI algorithm uses to determine the directionality of
+        * paragraphs ( http://unicode.org/reports/tr9/#The_Paragraph_Level ) and
+        * FSI isolates ( http://unicode.org/reports/tr9/#Explicit_Directional_Isolates ).
+        *
+        * TODO: Does not handle BIDI control characters inside the text.
+        * TODO: Does not handle unallocated characters.
+        *
+        * @param string $text Text to test
+        * @return null|string Directionality ('ltr' or 'rtl') or null
+        */
+       private static function strongDirFromContent( $text = '' ) {
+               if ( !preg_match( self::$strongDirRegex, $text, $matches ) ) {
+                       return null;
+               }
+               if ( $matches[1] === '' ) {
+                       return 'rtl';
+               }
+               return 'ltr';
        }
 
        /**
-        * Roman number formatting up to 3000
+        * Roman number formatting up to 10000
+        *
+        * @param int $num
+        *
+        * @return string
         */
        static function romanNumeral( $num ) {
-               static $table = array(
-                       array( '', 'I', 'II', 'III', 'IV', 'V', 'VI', 'VII', 'VIII', 'IX', 'X' ),
-                       array( '', 'X', 'XX', 'XXX', 'XL', 'L', 'LX', 'LXX', 'LXXX', 'XC', 'C' ),
-                       array( '', 'C', 'CC', 'CCC', 'CD', 'D', 'DC', 'DCC', 'DCCC', 'CM', 'M' ),
-                       array( '', 'M', 'MM', 'MMM' )
-               );
+               static $table = [
+                       [ '', 'I', 'II', 'III', 'IV', 'V', 'VI', 'VII', 'VIII', 'IX', 'X' ],
+                       [ '', 'X', 'XX', 'XXX', 'XL', 'L', 'LX', 'LXX', 'LXXX', 'XC', 'C' ],
+                       [ '', 'C', 'CC', 'CCC', 'CD', 'D', 'DC', 'DCC', 'DCCC', 'CM', 'M' ],
+                       [ '', 'M', 'MM', 'MMM', 'MMMM', 'MMMMM', 'MMMMMM', 'MMMMMMM',
+                               'MMMMMMMM', 'MMMMMMMMM', 'MMMMMMMMMM' ]
+               ];
 
                $num = intval( $num );
-               if ( $num > 3000 || $num <= 0 ) {
+               if ( $num > 10000 || $num <= 0 ) {
                        return $num;
                }
 
                $s = '';
                for ( $pow10 = 1000, $i = 3; $i >= 0; $pow10 /= 10, $i-- ) {
                        if ( $num >= $pow10 ) {
-                               $s .= $table[$i][floor( $num / $pow10 )];
+                               $s .= $table[$i][(int)floor( $num / $pow10 )];
                        }
                        $num = $num % $pow10;
                }
                return $s;
        }
 
-       /**
+       /**
         * Hebrew Gematria number formatting up to 9999
+        *
+        * @param int $num
+        *
+        * @return string
         */
        static function hebrewNumeral( $num ) {
-               static $table = array(
-                       array( '', 'א', 'ב', 'ג', 'ד', 'ה', 'ו', 'ז', 'ח', 'ט', 'י' ),
-                       array( '', 'י', 'כ', 'ל', 'מ', 'נ', 'ס', 'ע', 'פ', 'צ', 'ק' ),
-                       array( '', 'ק', 'ר', 'ש', 'ת', 'תק', 'תר', 'תש', 'תת', 'תתק', 'תתר' ),
-                       array( '', 'א', 'ב', 'ג', 'ד', 'ה', 'ו', 'ז', 'ח', 'ט', 'י' )
-               );
+               static $table = [
+                       [ '', 'א', 'ב', 'ג', 'ד', 'ה', 'ו', 'ז', 'ח', 'ט', 'י' ],
+                       [ '', 'י', 'כ', 'ל', 'מ', 'נ', 'ס', 'ע', 'פ', 'צ', 'ק' ],
+                       [ '',
+                               [ 'ק' ],
+                               [ 'ר' ],
+                               [ 'ש' ],
+                               [ 'ת' ],
+                               [ 'ת', 'ק' ],
+                               [ 'ת', 'ר' ],
+                               [ 'ת', 'ש' ],
+                               [ 'ת', 'ת' ],
+                               [ 'ת', 'ת', 'ק' ],
+                               [ 'ת', 'ת', 'ר' ],
+                       ],
+                       [ '', 'א', 'ב', 'ג', 'ד', 'ה', 'ו', 'ז', 'ח', 'ט', 'י' ]
+               ];
 
                $num = intval( $num );
                if ( $num > 9999 || $num <= 0 ) {
                        return $num;
                }
 
-               $s = '';
+               // Round thousands have special notations
+               if ( $num === 1000 ) {
+                       return "א' אלף";
+               } elseif ( $num % 1000 === 0 ) {
+                       return $table[0][$num / 1000] . "' אלפים";
+               }
+
+               $letters = [];
+
                for ( $pow10 = 1000, $i = 3; $i >= 0; $pow10 /= 10, $i-- ) {
                        if ( $num >= $pow10 ) {
-                               if ( $num == 15 || $num == 16 ) {
-                                       $s .= $table[0][9] . $table[0][$num - 9];
+                               if ( $num === 15 || $num === 16 ) {
+                                       $letters[] = $table[0][9];
+                                       $letters[] = $table[0][$num - 9];
                                        $num = 0;
                                } else {
-                                       $s .= $table[$i][intval( ( $num / $pow10 ) )];
-                                       if ( $pow10 == 1000 ) {
-                                               $s .= "'";
+                                       $letters = array_merge(
+                                               $letters,
+                                               (array)$table[$i][intval( $num / $pow10 )]
+                                       );
+
+                                       if ( $pow10 === 1000 ) {
+                                               $letters[] = "'";
                                        }
                                }
                        }
+
                        $num = $num % $pow10;
                }
-               if ( strlen( $s ) == 2 ) {
-                       $str = $s . "'";
-               } else  {
-                       $str = substr( $s, 0, strlen( $s ) - 2 ) . '"';
-                       $str .= substr( $s, strlen( $s ) - 2, 2 );
-               }
-               $start = substr( $str, 0, strlen( $str ) - 2 );
-               $end = substr( $str, strlen( $str ) - 2 );
-               switch( $end ) {
-                       case 'כ':
-                               $str = $start . 'ך';
-                               break;
-                       case 'מ':
-                               $str = $start . 'ם';
-                               break;
-                       case 'נ':
-                               $str = $start . 'ן';
-                               break;
-                       case 'פ':
-                               $str = $start . 'ף';
-                               break;
-                       case 'צ':
-                               $str = $start . 'ץ';
-                               break;
+
+               $preTransformLength = count( $letters );
+               if ( $preTransformLength === 1 ) {
+                       // Add geresh (single quote) to one-letter numbers
+                       $letters[] = "'";
+               } else {
+                       $lastIndex = $preTransformLength - 1;
+                       $letters[$lastIndex] = str_replace(
+                               [ 'כ', 'מ', 'נ', 'פ', 'צ' ],
+                               [ 'ך', 'ם', 'ן', 'ף', 'ץ' ],
+                               $letters[$lastIndex]
+                       );
+
+                       // Add gershayim (double quote) to multiple-letter numbers,
+                       // but exclude numbers with only one letter after the thousands
+                       // (1001-1009, 1020, 1030, 2001-2009, etc.)
+                       if ( $letters[1] === "'" && $preTransformLength === 3 ) {
+                               $letters[] = "'";
+                       } else {
+                               array_splice( $letters, -1, 0, '"' );
+                       }
+               }
+
+               return implode( $letters );
+       }
+
+       /**
+        * Used by date() and time() to adjust the time output.
+        *
+        * @param string $ts The time in date('YmdHis') format
+        * @param mixed $tz Adjust the time by this amount (default false, mean we
+        *   get user timecorrection setting)
+        * @return int
+        */
+       public function userAdjust( $ts, $tz = false ) {
+               global $wgUser, $wgLocalTZoffset;
+
+               if ( $tz === false ) {
+                       $tz = $wgUser->getOption( 'timecorrection' );
+               }
+
+               $data = explode( '|', $tz, 3 );
+
+               if ( $data[0] == 'ZoneInfo' ) {
+                       try {
+                               $userTZ = new DateTimeZone( $data[2] );
+                               $date = new DateTime( $ts, new DateTimeZone( 'UTC' ) );
+                               $date->setTimezone( $userTZ );
+                               return $date->format( 'YmdHis' );
+                       } catch ( Exception $e ) {
+                               // Unrecognized timezone, default to 'Offset' with the stored offset.
+                               $data[0] = 'Offset';
+                       }
+               }
+
+               if ( $data[0] == 'System' || $tz == '' ) {
+                       # Global offset in minutes.
+                       $minDiff = $wgLocalTZoffset;
+               } elseif ( $data[0] == 'Offset' ) {
+                       $minDiff = intval( $data[1] );
+               } else {
+                       $data = explode( ':', $tz );
+                       if ( count( $data ) == 2 ) {
+                               $data[0] = intval( $data[0] );
+                               $data[1] = intval( $data[1] );
+                               $minDiff = abs( $data[0] ) * 60 + $data[1];
+                               if ( $data[0] < 0 ) {
+                                       $minDiff = -$minDiff;
+                               }
+                       } else {
+                               $minDiff = intval( $data[0] ) * 60;
+                       }
                }
-               return $str;
+
+               # No difference ? Return time unchanged
+               if ( 0 == $minDiff ) {
+                       return $ts;
+               }
+
+               MediaWiki\suppressWarnings(); // E_STRICT system time bitching
+               # Generate an adjusted date; take advantage of the fact that mktime
+               # will normalize out-of-range values so we don't have to split $minDiff
+               # into hours and minutes.
+               $t = mktime( (
+                       (int)substr( $ts, 8, 2 ) ), # Hours
+                       (int)substr( $ts, 10, 2 ) + $minDiff, # Minutes
+                       (int)substr( $ts, 12, 2 ), # Seconds
+                       (int)substr( $ts, 4, 2 ), # Month
+                       (int)substr( $ts, 6, 2 ), # Day
+                       (int)substr( $ts, 0, 4 ) ); # Year
+
+               $date = date( 'YmdHis', $t );
+               MediaWiki\restoreWarnings();
+
+               return $date;
        }
 
        /**
@@ -1447,16 +2163,14 @@ class Language {
         * the date preference they're supposed to use, it should be used in
         * all children.
         *
-        *<code>
-        * function timeanddate([...], $format = true) {
-        *      $datePreference = $this->dateFormat($format);
-        * [...]
-        * }
-        *</code>
+        *     function timeanddate([...], $format = true) {
+        *       $datePreference = $this->dateFormat($format);
+        *       [...]
+        *     }
         *
-        * @param $usePrefs Mixed: if true, the user's preference is used
-        *                         if false, the site/language default is used
-        *                         if int/string, assumed to be a format.
+        * @param int|string|bool $usePrefs If true, the user's preference is used
+        *   if false, the site/language default is used
+        *   if int/string, assumed to be a format.
         * @return string
         */
        function dateFormat( $usePrefs = true ) {
@@ -1482,37 +2196,49 @@ class Language {
 
        /**
         * Get a format string for a given type and preference
-        * @param $type May be date, time or both
-        * @param $pref The format name as it appears in Messages*.php
+        * @param string $type May be 'date', 'time', 'both', or 'pretty'.
+        * @param string $pref The format name as it appears in Messages*.php under
+        *  $datePreferences.
+        *
+        * @since 1.22 New type 'pretty' that provides a more readable timestamp format
+        *
+        * @return string
         */
        function getDateFormatString( $type, $pref ) {
+               $wasDefault = false;
+               if ( $pref == 'default' ) {
+                       $wasDefault = true;
+                       $pref = $this->getDefaultDateFormat();
+               }
+
                if ( !isset( $this->dateFormatStrings[$type][$pref] ) ) {
-                       if ( $pref == 'default' ) {
+                       $df = self::$dataCache->getSubitem( $this->mCode, 'dateFormats', "$pref $type" );
+
+                       if ( $type === 'pretty' && $df === null ) {
+                               $df = $this->getDateFormatString( 'date', $pref );
+                       }
+
+                       if ( !$wasDefault && $df === null ) {
                                $pref = $this->getDefaultDateFormat();
                                $df = self::$dataCache->getSubitem( $this->mCode, 'dateFormats', "$pref $type" );
-                       } else {
-                               $df = self::$dataCache->getSubitem( $this->mCode, 'dateFormats', "$pref $type" );
-                               if ( is_null( $df ) ) {
-                                       $pref = $this->getDefaultDateFormat();
-                                       $df = self::$dataCache->getSubitem( $this->mCode, 'dateFormats', "$pref $type" );
-                               }
                        }
+
                        $this->dateFormatStrings[$type][$pref] = $df;
                }
                return $this->dateFormatStrings[$type][$pref];
        }
 
        /**
-        * @param $ts Mixed: the time format which needs to be turned into a
-        *            date('YmdHis') format with wfTimestamp(TS_MW,$ts)
-        * @param $adj Bool: whether to adjust the time output according to the
-        *             user configured offset ($timecorrection)
-        * @param $format Mixed: true to use user's date format preference
-        * @param $timecorrection String: the time offset as returned by
-        *                        validateTimeZone() in Special:Preferences
+        * @param string $ts The time format which needs to be turned into a
+        *   date('YmdHis') format with wfTimestamp(TS_MW,$ts)
+        * @param bool $adj Whether to adjust the time output according to the
+        *   user configured offset ($timecorrection)
+        * @param mixed $format True to use user's date format preference
+        * @param string|bool $timecorrection The time offset as returned by
+        *   validateTimeZone() in Special:Preferences
         * @return string
         */
-       function date( $ts, $adj = false, $format = true, $timecorrection = false ) {
+       public function date( $ts, $adj = false, $format = true, $timecorrection = false ) {
                $ts = wfTimestamp( TS_MW, $ts );
                if ( $adj ) {
                        $ts = $this->userAdjust( $ts, $timecorrection );
@@ -1522,16 +2248,16 @@ class Language {
        }
 
        /**
-        * @param $ts Mixed: the time format which needs to be turned into a
-        *            date('YmdHis') format with wfTimestamp(TS_MW,$ts)
-        * @param $adj Bool: whether to adjust the time output according to the
-        *             user configured offset ($timecorrection)
-        * @param $format Mixed: true to use user's date format preference
-        * @param $timecorrection String: the time offset as returned by
-        *                        validateTimeZone() in Special:Preferences
+        * @param string $ts The time format which needs to be turned into a
+        *   date('YmdHis') format with wfTimestamp(TS_MW,$ts)
+        * @param bool $adj Whether to adjust the time output according to the
+        *   user configured offset ($timecorrection)
+        * @param mixed $format True to use user's date format preference
+        * @param string|bool $timecorrection The time offset as returned by
+        *   validateTimeZone() in Special:Preferences
         * @return string
         */
-       function time( $ts, $adj = false, $format = true, $timecorrection = false ) {
+       public function time( $ts, $adj = false, $format = true, $timecorrection = false ) {
                $ts = wfTimestamp( TS_MW, $ts );
                if ( $adj ) {
                        $ts = $this->userAdjust( $ts, $timecorrection );
@@ -1541,17 +2267,17 @@ class Language {
        }
 
        /**
-        * @param $ts Mixed: the time format which needs to be turned into a
-        *            date('YmdHis') format with wfTimestamp(TS_MW,$ts)
-        * @param $adj Bool: whether to adjust the time output according to the
-        *             user configured offset ($timecorrection)
-        * @param $format Mixed: what format to return, if it's false output the
-        *                default one (default true)
-        * @param $timecorrection String: the time offset as returned by
-        *                        validateTimeZone() in Special:Preferences
+        * @param string $ts The time format which needs to be turned into a
+        *   date('YmdHis') format with wfTimestamp(TS_MW,$ts)
+        * @param bool $adj Whether to adjust the time output according to the
+        *   user configured offset ($timecorrection)
+        * @param mixed $format What format to return, if it's false output the
+        *   default one (default true)
+        * @param string|bool $timecorrection The time offset as returned by
+        *   validateTimeZone() in Special:Preferences
         * @return string
         */
-       function timeanddate( $ts, $adj = false, $format = true, $timecorrection = false ) {
+       public function timeanddate( $ts, $adj = false, $format = true, $timecorrection = false ) {
                $ts = wfTimestamp( TS_MW, $ts );
                if ( $adj ) {
                        $ts = $this->userAdjust( $ts, $timecorrection );
@@ -1560,70 +2286,365 @@ class Language {
                return $this->sprintfDate( $df, $ts );
        }
 
-       function getMessage( $key ) {
-               // Don't change getPreferredVariant() to getCode() / mCode, because:
+       /**
+        * Takes a number of seconds and turns it into a text using values such as hours and minutes.
+        *
+        * @since 1.20
+        *
+        * @param int $seconds The amount of seconds.
+        * @param array $chosenIntervals The intervals to enable.
+        *
+        * @return string
+        */
+       public function formatDuration( $seconds, array $chosenIntervals = [] ) {
+               $intervals = $this->getDurationIntervals( $seconds, $chosenIntervals );
 
-               // 1. Some language like Chinese has multiple variant languages. Only
-               //    getPreferredVariant() (in LanguageConverter) could return a
-               //    sub-language which would be more suitable for the user.
-               // 2. To languages without multiple variants, getPreferredVariant()
-               //    (in FakeConverter) functions exactly same as getCode() / mCode,
-               //    it won't break anything.
+               $segments = [];
 
-               // The same below.
-               return self::$dataCache->getSubitem( $this->getPreferredVariant(), 'messages', $key );
-       }
+               foreach ( $intervals as $intervalName => $intervalValue ) {
+                       // Messages: duration-seconds, duration-minutes, duration-hours, duration-days, duration-weeks,
+                       // duration-years, duration-decades, duration-centuries, duration-millennia
+                       $message = wfMessage( 'duration-' . $intervalName )->numParams( $intervalValue );
+                       $segments[] = $message->inLanguage( $this )->escaped();
+               }
 
-       function getAllMessages() {
-               return self::$dataCache->getItem( $this->getPreferredVariant(), 'messages' );
+               return $this->listToText( $segments );
        }
 
-       function iconv( $in, $out, $string ) {
-               # This is a wrapper for iconv in all languages except esperanto,
-               # which does some nasty x-conversions beforehand
-
-               # Even with //IGNORE iconv can whine about illegal characters in
-               # *input* string. We just ignore those too.
-               # REF: http://bugs.php.net/bug.php?id=37166
-               # REF: https://bugzilla.wikimedia.org/show_bug.cgi?id=16885
-               wfSuppressWarnings();
-               $text = iconv( $in, $out . '//IGNORE', $string );
-               wfRestoreWarnings();
-               return $text;
+       /**
+        * Takes a number of seconds and returns an array with a set of corresponding intervals.
+        * For example 65 will be turned into [ minutes => 1, seconds => 5 ].
+        *
+        * @since 1.20
+        *
+        * @param int $seconds The amount of seconds.
+        * @param array $chosenIntervals The intervals to enable.
+        *
+        * @return array
+        */
+       public function getDurationIntervals( $seconds, array $chosenIntervals = [] ) {
+               if ( empty( $chosenIntervals ) ) {
+                       $chosenIntervals = [
+                               'millennia',
+                               'centuries',
+                               'decades',
+                               'years',
+                               'days',
+                               'hours',
+                               'minutes',
+                               'seconds'
+                       ];
+               }
+
+               $intervals = array_intersect_key( self::$durationIntervals, array_flip( $chosenIntervals ) );
+               $sortedNames = array_keys( $intervals );
+               $smallestInterval = array_pop( $sortedNames );
+
+               $segments = [];
+
+               foreach ( $intervals as $name => $length ) {
+                       $value = floor( $seconds / $length );
+
+                       if ( $value > 0 || ( $name == $smallestInterval && empty( $segments ) ) ) {
+                               $seconds -= $value * $length;
+                               $segments[$name] = $value;
+                       }
+               }
+
+               return $segments;
        }
 
-       // callback functions for uc(), lc(), ucwords(), ucwordbreaks()
-       function ucwordbreaksCallbackAscii( $matches ) {
-               return $this->ucfirst( $matches[1] );
+       /**
+        * Internal helper function for userDate(), userTime() and userTimeAndDate()
+        *
+        * @param string $type Can be 'date', 'time' or 'both'
+        * @param string $ts The time format which needs to be turned into a
+        *   date('YmdHis') format with wfTimestamp(TS_MW,$ts)
+        * @param User $user User object used to get preferences for timezone and format
+        * @param array $options Array, can contain the following keys:
+        *   - 'timecorrection': time correction, can have the following values:
+        *     - true: use user's preference
+        *     - false: don't use time correction
+        *     - int: value of time correction in minutes
+        *   - 'format': format to use, can have the following values:
+        *     - true: use user's preference
+        *     - false: use default preference
+        *     - string: format to use
+        * @since 1.19
+        * @return string
+        */
+       private function internalUserTimeAndDate( $type, $ts, User $user, array $options ) {
+               $ts = wfTimestamp( TS_MW, $ts );
+               $options += [ 'timecorrection' => true, 'format' => true ];
+               if ( $options['timecorrection'] !== false ) {
+                       if ( $options['timecorrection'] === true ) {
+                               $offset = $user->getOption( 'timecorrection' );
+                       } else {
+                               $offset = $options['timecorrection'];
+                       }
+                       $ts = $this->userAdjust( $ts, $offset );
+               }
+               if ( $options['format'] === true ) {
+                       $format = $user->getDatePreference();
+               } else {
+                       $format = $options['format'];
+               }
+               $df = $this->getDateFormatString( $type, $this->dateFormat( $format ) );
+               return $this->sprintfDate( $df, $ts );
        }
 
-       function ucwordbreaksCallbackMB( $matches ) {
-               return mb_strtoupper( $matches[0] );
+       /**
+        * Get the formatted date for the given timestamp and formatted for
+        * the given user.
+        *
+        * @param mixed $ts Mixed: the time format which needs to be turned into a
+        *   date('YmdHis') format with wfTimestamp(TS_MW,$ts)
+        * @param User $user User object used to get preferences for timezone and format
+        * @param array $options Array, can contain the following keys:
+        *   - 'timecorrection': time correction, can have the following values:
+        *     - true: use user's preference
+        *     - false: don't use time correction
+        *     - int: value of time correction in minutes
+        *   - 'format': format to use, can have the following values:
+        *     - true: use user's preference
+        *     - false: use default preference
+        *     - string: format to use
+        * @since 1.19
+        * @return string
+        */
+       public function userDate( $ts, User $user, array $options = [] ) {
+               return $this->internalUserTimeAndDate( 'date', $ts, $user, $options );
        }
 
-       function ucCallback( $matches ) {
-               list( $wikiUpperChars ) = self::getCaseMaps();
-               return strtr( $matches[1], $wikiUpperChars );
+       /**
+        * Get the formatted time for the given timestamp and formatted for
+        * the given user.
+        *
+        * @param mixed $ts The time format which needs to be turned into a
+        *   date('YmdHis') format with wfTimestamp(TS_MW,$ts)
+        * @param User $user User object used to get preferences for timezone and format
+        * @param array $options Array, can contain the following keys:
+        *   - 'timecorrection': time correction, can have the following values:
+        *     - true: use user's preference
+        *     - false: don't use time correction
+        *     - int: value of time correction in minutes
+        *   - 'format': format to use, can have the following values:
+        *     - true: use user's preference
+        *     - false: use default preference
+        *     - string: format to use
+        * @since 1.19
+        * @return string
+        */
+       public function userTime( $ts, User $user, array $options = [] ) {
+               return $this->internalUserTimeAndDate( 'time', $ts, $user, $options );
        }
 
-       function lcCallback( $matches ) {
-               list( , $wikiLowerChars ) = self::getCaseMaps();
-               return strtr( $matches[1], $wikiLowerChars );
+       /**
+        * Get the formatted date and time for the given timestamp and formatted for
+        * the given user.
+        *
+        * @param mixed $ts The time format which needs to be turned into a
+        *   date('YmdHis') format with wfTimestamp(TS_MW,$ts)
+        * @param User $user User object used to get preferences for timezone and format
+        * @param array $options Array, can contain the following keys:
+        *   - 'timecorrection': time correction, can have the following values:
+        *     - true: use user's preference
+        *     - false: don't use time correction
+        *     - int: value of time correction in minutes
+        *   - 'format': format to use, can have the following values:
+        *     - true: use user's preference
+        *     - false: use default preference
+        *     - string: format to use
+        * @since 1.19
+        * @return string
+        */
+       public function userTimeAndDate( $ts, User $user, array $options = [] ) {
+               return $this->internalUserTimeAndDate( 'both', $ts, $user, $options );
        }
 
-       function ucwordsCallbackMB( $matches ) {
+       /**
+        * Get the timestamp in a human-friendly relative format, e.g., "3 days ago".
+        *
+        * Determine the difference between the timestamp and the current time, and
+        * generate a readable timestamp by returning "<N> <units> ago", where the
+        * largest possible unit is used.
+        *
+        * @since 1.26 (Prior to 1.26 method existed but was not meant to be used directly)
+        *
+        * @param MWTimestamp $time
+        * @param MWTimestamp|null $relativeTo The base timestamp to compare to (defaults to now)
+        * @param User|null $user User the timestamp is being generated for
+        *  (or null to use main context's user)
+        * @return string Formatted timestamp
+        */
+       public function getHumanTimestamp(
+               MWTimestamp $time, MWTimestamp $relativeTo = null, User $user = null
+       ) {
+               if ( $relativeTo === null ) {
+                       $relativeTo = new MWTimestamp();
+               }
+               if ( $user === null ) {
+                       $user = RequestContext::getMain()->getUser();
+               }
+
+               // Adjust for the user's timezone.
+               $offsetThis = $time->offsetForUser( $user );
+               $offsetRel = $relativeTo->offsetForUser( $user );
+
+               $ts = '';
+               if ( Hooks::run( 'GetHumanTimestamp', [ &$ts, $time, $relativeTo, $user, $this ] ) ) {
+                       $ts = $this->getHumanTimestampInternal( $time, $relativeTo, $user );
+               }
+
+               // Reset the timezone on the objects.
+               $time->timestamp->sub( $offsetThis );
+               $relativeTo->timestamp->sub( $offsetRel );
+
+               return $ts;
+       }
+
+       /**
+        * Convert an MWTimestamp into a pretty human-readable timestamp using
+        * the given user preferences and relative base time.
+        *
+        * @see Language::getHumanTimestamp
+        * @param MWTimestamp $ts Timestamp to prettify
+        * @param MWTimestamp $relativeTo Base timestamp
+        * @param User $user User preferences to use
+        * @return string Human timestamp
+        * @since 1.26
+        */
+       private function getHumanTimestampInternal(
+               MWTimestamp $ts, MWTimestamp $relativeTo, User $user
+       ) {
+               $diff = $ts->diff( $relativeTo );
+               $diffDay = (bool)( (int)$ts->timestamp->format( 'w' ) -
+                       (int)$relativeTo->timestamp->format( 'w' ) );
+               $days = $diff->days ?: (int)$diffDay;
+               if ( $diff->invert || $days > 5
+                       && $ts->timestamp->format( 'Y' ) !== $relativeTo->timestamp->format( 'Y' )
+               ) {
+                       // Timestamps are in different years: use full timestamp
+                       // Also do full timestamp for future dates
+                       /**
+                        * @todo FIXME: Add better handling of future timestamps.
+                        */
+                       $format = $this->getDateFormatString( 'both', $user->getDatePreference() ?: 'default' );
+                       $ts = $this->sprintfDate( $format, $ts->getTimestamp( TS_MW ) );
+               } elseif ( $days > 5 ) {
+                       // Timestamps are in same year,  but more than 5 days ago: show day and month only.
+                       $format = $this->getDateFormatString( 'pretty', $user->getDatePreference() ?: 'default' );
+                       $ts = $this->sprintfDate( $format, $ts->getTimestamp( TS_MW ) );
+               } elseif ( $days > 1 ) {
+                       // Timestamp within the past week: show the day of the week and time
+                       $format = $this->getDateFormatString( 'time', $user->getDatePreference() ?: 'default' );
+                       $weekday = self::$mWeekdayMsgs[$ts->timestamp->format( 'w' )];
+                       // Messages:
+                       // sunday-at, monday-at, tuesday-at, wednesday-at, thursday-at, friday-at, saturday-at
+                       $ts = wfMessage( "$weekday-at" )
+                               ->inLanguage( $this )
+                               ->params( $this->sprintfDate( $format, $ts->getTimestamp( TS_MW ) ) )
+                               ->text();
+               } elseif ( $days == 1 ) {
+                       // Timestamp was yesterday: say 'yesterday' and the time.
+                       $format = $this->getDateFormatString( 'time', $user->getDatePreference() ?: 'default' );
+                       $ts = wfMessage( 'yesterday-at' )
+                               ->inLanguage( $this )
+                               ->params( $this->sprintfDate( $format, $ts->getTimestamp( TS_MW ) ) )
+                               ->text();
+               } elseif ( $diff->h > 1 || $diff->h == 1 && $diff->i > 30 ) {
+                       // Timestamp was today, but more than 90 minutes ago: say 'today' and the time.
+                       $format = $this->getDateFormatString( 'time', $user->getDatePreference() ?: 'default' );
+                       $ts = wfMessage( 'today-at' )
+                               ->inLanguage( $this )
+                               ->params( $this->sprintfDate( $format, $ts->getTimestamp( TS_MW ) ) )
+                               ->text();
+
+               // From here on in, the timestamp was soon enough ago so that we can simply say
+               // XX units ago, e.g., "2 hours ago" or "5 minutes ago"
+               } elseif ( $diff->h == 1 ) {
+                       // Less than 90 minutes, but more than an hour ago.
+                       $ts = wfMessage( 'hours-ago' )->inLanguage( $this )->numParams( 1 )->text();
+               } elseif ( $diff->i >= 1 ) {
+                       // A few minutes ago.
+                       $ts = wfMessage( 'minutes-ago' )->inLanguage( $this )->numParams( $diff->i )->text();
+               } elseif ( $diff->s >= 30 ) {
+                       // Less than a minute, but more than 30 sec ago.
+                       $ts = wfMessage( 'seconds-ago' )->inLanguage( $this )->numParams( $diff->s )->text();
+               } else {
+                       // Less than 30 seconds ago.
+                       $ts = wfMessage( 'just-now' )->text();
+               }
+
+               return $ts;
+       }
+
+       /**
+        * @param string $key
+        * @return string|null
+        */
+       public function getMessage( $key ) {
+               return self::$dataCache->getSubitem( $this->mCode, 'messages', $key );
+       }
+
+       /**
+        * @return array
+        */
+       function getAllMessages() {
+               return self::$dataCache->getItem( $this->mCode, 'messages' );
+       }
+
+       /**
+        * @param string $in
+        * @param string $out
+        * @param string $string
+        * @return string
+        */
+       public function iconv( $in, $out, $string ) {
+               # Even with //IGNORE iconv can whine about illegal characters in
+               # *input* string. We just ignore those too.
+               # REF: https://bugs.php.net/bug.php?id=37166
+               # REF: https://phabricator.wikimedia.org/T18885
+               MediaWiki\suppressWarnings();
+               $text = iconv( $in, $out . '//IGNORE', $string );
+               MediaWiki\restoreWarnings();
+               return $text;
+       }
+
+       // callback functions for ucwords(), ucwordbreaks()
+
+       /**
+        * @param array $matches
+        * @return mixed|string
+        */
+       function ucwordbreaksCallbackAscii( $matches ) {
+               return $this->ucfirst( $matches[1] );
+       }
+
+       /**
+        * @param array $matches
+        * @return string
+        */
+       function ucwordbreaksCallbackMB( $matches ) {
                return mb_strtoupper( $matches[0] );
        }
 
-       function ucwordsCallbackWiki( $matches ) {
-               list( $wikiUpperChars ) = self::getCaseMaps();
-               return strtr( $matches[0], $wikiUpperChars );
+       /**
+        * @param array $matches
+        * @return string
+        */
+       function ucwordsCallbackMB( $matches ) {
+               return mb_strtoupper( $matches[0] );
        }
 
        /**
         * Make a string's first character uppercase
+        *
+        * @param string $str
+        *
+        * @return string
         */
-       function ucfirst( $str ) {
+       public function ucfirst( $str ) {
                $o = ord( $str );
                if ( $o < 96 ) { // if already uppercase...
                        return $str;
@@ -1637,32 +2658,28 @@ class Language {
 
        /**
         * Convert a string to uppercase
+        *
+        * @param string $str
+        * @param bool $first
+        *
+        * @return string
         */
-       function uc( $str, $first = false ) {
-               if ( function_exists( 'mb_strtoupper' ) ) {
-                       if ( $first ) {
-                               if ( $this->isMultibyte( $str ) ) {
-                                       return mb_strtoupper( mb_substr( $str, 0, 1 ) ) . mb_substr( $str, 1 );
-                               } else {
-                                       return ucfirst( $str );
-                               }
-                       } else {
-                               return $this->isMultibyte( $str ) ? mb_strtoupper( $str ) : strtoupper( $str );
-                       }
-               } else {
+       public function uc( $str, $first = false ) {
+               if ( $first ) {
                        if ( $this->isMultibyte( $str ) ) {
-                               $x = $first ? '^' : '';
-                               return preg_replace_callback(
-                                       "/$x([a-z]|[\\xc0-\\xff][\\x80-\\xbf]*)/",
-                                       array( $this, 'ucCallback' ),
-                                       $str
-                               );
+                               return mb_strtoupper( mb_substr( $str, 0, 1 ) ) . mb_substr( $str, 1 );
                        } else {
-                               return $first ? ucfirst( $str ) : strtoupper( $str );
+                               return ucfirst( $str );
                        }
+               } else {
+                       return $this->isMultibyte( $str ) ? mb_strtoupper( $str ) : strtoupper( $str );
                }
        }
 
+       /**
+        * @param string $str
+        * @return mixed|string
+        */
        function lcfirst( $str ) {
                $o = ord( $str );
                if ( !$o ) {
@@ -1677,35 +2694,35 @@ class Language {
                }
        }
 
+       /**
+        * @param string $str
+        * @param bool $first
+        * @return mixed|string
+        */
        function lc( $str, $first = false ) {
-               if ( function_exists( 'mb_strtolower' ) ) {
-                       if ( $first ) {
-                               if ( $this->isMultibyte( $str ) ) {
-                                       return mb_strtolower( mb_substr( $str, 0, 1 ) ) . mb_substr( $str, 1 );
-                               } else {
-                                       return strtolower( substr( $str, 0, 1 ) ) . substr( $str, 1 );
-                               }
-                       } else {
-                               return $this->isMultibyte( $str ) ? mb_strtolower( $str ) : strtolower( $str );
-                       }
-               } else {
+               if ( $first ) {
                        if ( $this->isMultibyte( $str ) ) {
-                               $x = $first ? '^' : '';
-                               return preg_replace_callback(
-                                       "/$x([A-Z]|[\\xc0-\\xff][\\x80-\\xbf]*)/",
-                                       array( $this, 'lcCallback' ),
-                                       $str
-                               );
+                               return mb_strtolower( mb_substr( $str, 0, 1 ) ) . mb_substr( $str, 1 );
                        } else {
-                               return $first ? strtolower( substr( $str, 0, 1 ) ) . substr( $str, 1 ) : strtolower( $str );
+                               return strtolower( substr( $str, 0, 1 ) ) . substr( $str, 1 );
                        }
+               } else {
+                       return $this->isMultibyte( $str ) ? mb_strtolower( $str ) : strtolower( $str );
                }
        }
 
+       /**
+        * @param string $str
+        * @return bool
+        */
        function isMultibyte( $str ) {
-               return (bool)preg_match( '/[\x80-\xff]/', $str );
+               return strlen( $str ) !== mb_strlen( $str );
        }
 
+       /**
+        * @param string $str
+        * @return mixed|string
+        */
        function ucwords( $str ) {
                if ( $this->isMultibyte( $str ) ) {
                        $str = $this->lc( $str );
@@ -1714,25 +2731,22 @@ class Language {
                        $replaceRegexp = "/^([a-z]|[\\xc0-\\xff][\\x80-\\xbf]*)| ([a-z]|[\\xc0-\\xff][\\x80-\\xbf]*)/";
 
                        // function to use to capitalize a single char
-                       if ( function_exists( 'mb_strtoupper' ) ) {
-                               return preg_replace_callback(
-                                       $replaceRegexp,
-                                       array( $this, 'ucwordsCallbackMB' ),
-                                       $str
-                               );
-                       } else {
-                               return preg_replace_callback(
-                                       $replaceRegexp,
-                                       array( $this, 'ucwordsCallbackWiki' ),
-                                       $str
-                               );
-                       }
+                       return preg_replace_callback(
+                               $replaceRegexp,
+                               [ $this, 'ucwordsCallbackMB' ],
+                               $str
+                       );
                } else {
                        return ucwords( strtolower( $str ) );
                }
        }
 
-       # capitalize words at word breaks
+       /**
+        * capitalize words at word breaks
+        *
+        * @param string $str
+        * @return mixed
+        */
        function ucwordbreaks( $str ) {
                if ( $this->isMultibyte( $str ) ) {
                        $str = $this->lc( $str );
@@ -1741,25 +2755,18 @@ class Language {
                        $breaks = "[ \-\(\)\}\{\.,\?!]";
 
                        // find first letter after word break
-                       $replaceRegexp = "/^([a-z]|[\\xc0-\\xff][\\x80-\\xbf]*)|$breaks([a-z]|[\\xc0-\\xff][\\x80-\\xbf]*)/";
-
-                       if ( function_exists( 'mb_strtoupper' ) ) {
-                               return preg_replace_callback(
-                                       $replaceRegexp,
-                                       array( $this, 'ucwordbreaksCallbackMB' ),
-                                       $str
-                               );
-                       } else {
-                               return preg_replace_callback(
-                                       $replaceRegexp,
-                                       array( $this, 'ucwordsCallbackWiki' ),
-                                       $str
-                               );
-                       }
+                       $replaceRegexp = "/^([a-z]|[\\xc0-\\xff][\\x80-\\xbf]*)|" .
+                               "$breaks([a-z]|[\\xc0-\\xff][\\x80-\\xbf]*)/";
+
+                       return preg_replace_callback(
+                               $replaceRegexp,
+                               [ $this, 'ucwordbreaksCallbackMB' ],
+                               $str
+                       );
                } else {
                        return preg_replace_callback(
                                '/\b([\w\x80-\xff]+)\b/',
-                               array( $this, 'ucwordbreaksCallbackAscii' ),
+                               [ $this, 'ucwordbreaksCallbackAscii' ],
                                $str
                        );
                }
@@ -1775,30 +2782,34 @@ class Language {
         * Do *not* perform any other normalisation in this function. If a caller
         * uses this function when it should be using a more general normalisation
         * function, then fix the caller.
+        *
+        * @param string $s
+        *
+        * @return string
         */
        function caseFold( $s ) {
                return $this->uc( $s );
        }
 
+       /**
+        * @param string $s
+        * @return string
+        * @throws MWException
+        */
        function checkTitleEncoding( $s ) {
                if ( is_array( $s ) ) {
-                       wfDebugDieBacktrace( 'Given array to checkTitleEncoding.' );
-               }
-               # Check for non-UTF-8 URLs
-               $ishigh = preg_match( '/[\x80-\xff]/', $s );
-               if ( !$ishigh ) {
-                       return $s;
+                       throw new MWException( 'Given array to checkTitleEncoding.' );
                }
-
-               $isutf8 = preg_match( '/^([\x00-\x7f]|[\xc0-\xdf][\x80-\xbf]|' .
-                '[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xf7][\x80-\xbf]{3})+$/', $s );
-               if ( $isutf8 ) {
+               if ( StringUtils::isUtf8( $s ) ) {
                        return $s;
                }
 
                return $this->iconv( $this->fallback8bitEncoding(), 'utf-8', $s );
        }
 
+       /**
+        * @return array
+        */
        function fallback8bitEncoding() {
                return self::$dataCache->getItem( $this->mCode, 'fallback8bitEncoding' );
        }
@@ -1808,6 +2819,8 @@ class Language {
         * Some languages such as Chinese don't conventionally do this,
         * which requires special handling when breaking up words for
         * searching etc.
+        *
+        * @return bool
         */
        function hasWordBreaks() {
                return true;
@@ -1817,8 +2830,8 @@ class Language {
         * Some languages such as Chinese require word segmentation,
         * Specify such segmentation when overridden in derived class.
         *
-        * @param $string String
-        * @return String
+        * @param string $string
+        * @return string
         */
        function segmentByWord( $string ) {
                return $string;
@@ -1828,8 +2841,8 @@ class Language {
         * Some languages have special punctuation need to be normalized.
         * Make such changes here.
         *
-        * @param $string String
-        * @return String
+        * @param string $string
+        * @return string
         */
        function normalizeForSearch( $string ) {
                return self::convertDoubleWidth( $string );
@@ -1838,6 +2851,10 @@ class Language {
        /**
         * convert double-width roman characters to single-width.
         * range: ff00-ff5f ~= 0020-007f
+        *
+        * @param string $string
+        *
+        * @return string
         */
        protected static function convertDoubleWidth( $string ) {
                static $full = null;
@@ -1854,12 +2871,21 @@ class Language {
                return $string;
        }
 
+       /**
+        * @param string $string
+        * @param string $pattern
+        * @return string
+        */
        protected static function insertSpace( $string, $pattern ) {
                $string = preg_replace( $pattern, " $1 ", $string );
                $string = preg_replace( '/ +/', ' ', $string );
                return $string;
        }
 
+       /**
+        * @param array $termsArray
+        * @return array
+        */
        function convertForSearchResult( $termsArray ) {
                # some languages, e.g. Chinese, need to do a conversion
                # in order for search results to be displayed correctly
@@ -1869,11 +2895,11 @@ class Language {
        /**
         * Get the first character of a string.
         *
-        * @param $s string
+        * @param string $s
         * @return string
         */
        function firstChar( $s ) {
-               $matches = array();
+               $matches = [];
                preg_match(
                        '/^([\x00-\x7f]|[\xc0-\xdf][\x80-\xbf]|' .
                                '[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xf7][\x80-\xbf]{3})/',
@@ -1887,7 +2913,7 @@ class Language {
                        }
 
                        // Break down Hangul syllables to grab the first jamo
-                       $code = utf8ToCodepoint( $matches[1] );
+                       $code = UtfNormal\Utils::utf8ToCodepoint( $matches[1] );
                        if ( $code < 0xac00 || 0xd7a4 <= $code ) {
                                return $matches[1];
                        } elseif ( $code < 0xb098 ) {
@@ -1924,41 +2950,29 @@ class Language {
                }
        }
 
+       /**
+        * @deprecated No-op since 1.28
+        */
        function initEncoding() {
-               # Some languages may have an alternate char encoding option
-               # (Esperanto X-coding, Japanese furigana conversion, etc)
-               # If this language is used as the primary content language,
-               # an override to the defaults can be set here on startup.
+               // No-op.
        }
 
+       /**
+        * @param string $s
+        * @return string
+        * @deprecated No-op since 1.28
+        */
        function recodeForEdit( $s ) {
-               # For some languages we'll want to explicitly specify
-               # which characters make it into the edit box raw
-               # or are converted in some way or another.
-               # Note that if wgOutputEncoding is different from
-               # wgInputEncoding, this text will be further converted
-               # to wgOutputEncoding.
-               global $wgEditEncoding;
-               if ( $wgEditEncoding == '' || $wgEditEncoding == 'UTF-8' ) {
-                       return $s;
-               } else {
-                       return $this->iconv( 'UTF-8', $wgEditEncoding, $s );
-               }
+               return $s;
        }
 
+       /**
+        * @param string $s
+        * @return string
+        * @deprecated No-op since 1.28
+        */
        function recodeInput( $s ) {
-               # Take the previous into account.
-               global $wgEditEncoding;
-               if ( $wgEditEncoding != '' ) {
-                       $enc = $wgEditEncoding;
-               } else {
-                       $enc = 'UTF-8';
-               }
-               if ( $enc == 'UTF-8' ) {
-                       return $s;
-               } else {
-                       return $this->iconv( $enc, 'UTF-8', $s );
-               }
+               return $s;
        }
 
        /**
@@ -1967,10 +2981,14 @@ class Language {
         * to the modern Unicode equivalent.
         *
         * This is language-specific for performance reasons only.
+        *
+        * @param string $s
+        *
+        * @return string
         */
        function normalize( $s ) {
                global $wgAllUnicodeFixes;
-               $s = UtfNormal::cleanUp( $s );
+               $s = UtfNormal\Validator::cleanUp( $s );
                if ( $wgAllUnicodeFixes ) {
                        $s = $this->transformUsingPairFile( 'normalize-ar.ser', $s );
                        $s = $this->transformUsingPairFile( 'normalize-ml.ser', $s );
@@ -1986,6 +3004,12 @@ class Language {
         *
         * The data is cached in process memory. This will go faster if you have the
         * FastStringSearch extension.
+        *
+        * @param string $file
+        * @param string $string
+        *
+        * @throws MWException
+        * @return string
         */
        function transformUsingPairFile( $file, $string ) {
                if ( !isset( $this->transformData[$file] ) ) {
@@ -2009,7 +3033,7 @@ class Language {
 
        /**
         * Return the correct HTML 'dir' attribute value for this language.
-        * @return String
+        * @return string
         */
        function getDir() {
                return $this->isRTL() ? 'rtl' : 'ltr';
@@ -2021,7 +3045,7 @@ class Language {
         *
         * Should be equivalent to CSS3 'start' text-align value....
         *
-        * @return String
+        * @return string
         */
        function alignStart() {
                return $this->isRTL() ? 'right' : 'left';
@@ -2033,32 +3057,78 @@ class Language {
         *
         * Should be equivalent to CSS3 'end' text-align value....
         *
-        * @return String
+        * @return string
         */
        function alignEnd() {
                return $this->isRTL() ? 'left' : 'right';
        }
 
        /**
-        * A hidden direction mark (LRM or RLM), depending on the language direction
+        * A hidden direction mark (LRM or RLM), depending on the language direction.
+        * Unlike getDirMark(), this function returns the character as an HTML entity.
+        * This function should be used when the output is guaranteed to be HTML,
+        * because it makes the output HTML source code more readable. When
+        * the output is plain text or can be escaped, getDirMark() should be used.
         *
+        * @param bool $opposite Get the direction mark opposite to your language
         * @return string
+        * @since 1.20
         */
-       function getDirMark() {
-               return $this->isRTL() ? "\xE2\x80\x8F" : "\xE2\x80\x8E";
+       function getDirMarkEntity( $opposite = false ) {
+               if ( $opposite ) {
+                       return $this->isRTL() ? '&lrm;' : '&rlm;';
+               }
+               return $this->isRTL() ? '&rlm;' : '&lrm;';
+       }
+
+       /**
+        * A hidden direction mark (LRM or RLM), depending on the language direction.
+        * This function produces them as invisible Unicode characters and
+        * the output may be hard to read and debug, so it should only be used
+        * when the output is plain text or can be escaped. When the output is
+        * HTML, use getDirMarkEntity() instead.
+        *
+        * @param bool $opposite Get the direction mark opposite to your language
+        * @return string
+        */
+       function getDirMark( $opposite = false ) {
+               $lrm = "\xE2\x80\x8E"; # LEFT-TO-RIGHT MARK, commonly abbreviated LRM
+               $rlm = "\xE2\x80\x8F"; # RIGHT-TO-LEFT MARK, commonly abbreviated RLM
+               if ( $opposite ) {
+                       return $this->isRTL() ? $lrm : $rlm;
+               }
+               return $this->isRTL() ? $rlm : $lrm;
        }
 
+       /**
+        * @return array
+        */
        function capitalizeAllNouns() {
                return self::$dataCache->getItem( $this->mCode, 'capitalizeAllNouns' );
        }
 
        /**
-        * An arrow, depending on the language direction
+        * An arrow, depending on the language direction.
         *
+        * @param string $direction The direction of the arrow: forwards (default),
+        *   backwards, left, right, up, down.
         * @return string
         */
-       function getArrow() {
-               return $this->isRTL() ? '←' : '→';
+       function getArrow( $direction = 'forwards' ) {
+               switch ( $direction ) {
+               case 'forwards':
+                       return $this->isRTL() ? '←' : '→';
+               case 'backwards':
+                       return $this->isRTL() ? '→' : '←';
+               case 'left':
+                       return '←';
+               case 'right':
+                       return '→';
+               case 'up':
+                       return '↑';
+               case 'down':
+                       return '↓';
+               }
        }
 
        /**
@@ -2070,31 +3140,45 @@ class Language {
                return self::$dataCache->getItem( $this->mCode, 'linkPrefixExtension' );
        }
 
+       /**
+        * Get all magic words from cache.
+        * @return array
+        */
        function getMagicWords() {
                return self::$dataCache->getItem( $this->mCode, 'magicWords' );
        }
 
-       # Fill a MagicWord object with data from here
+       /**
+        * Run the LanguageGetMagic hook once.
+        */
+       protected function doMagicHook() {
+               if ( $this->mMagicHookDone ) {
+                       return;
+               }
+               $this->mMagicHookDone = true;
+               Hooks::run( 'LanguageGetMagic', [ &$this->mMagicExtensions, $this->getCode() ] );
+       }
+
+       /**
+        * Fill a MagicWord object with data from here
+        *
+        * @param MagicWord $mw
+        */
        function getMagic( $mw ) {
+               // Saves a function call
                if ( !$this->mMagicHookDone ) {
-                       $this->mMagicHookDone = true;
-                       wfProfileIn( 'LanguageGetMagic' );
-                       wfRunHooks( 'LanguageGetMagic', array( &$this->mMagicExtensions, $this->getCode() ) );
-                       wfProfileOut( 'LanguageGetMagic' );
+                       $this->doMagicHook();
                }
+
                if ( isset( $this->mMagicExtensions[$mw->mId] ) ) {
                        $rawEntry = $this->mMagicExtensions[$mw->mId];
                } else {
-                       $magicWords = $this->getMagicWords();
-                       if ( isset( $magicWords[$mw->mId] ) ) {
-                               $rawEntry = $magicWords[$mw->mId];
-                       } else {
-                               $rawEntry = false;
-                       }
+                       $rawEntry = self::$dataCache->getSubitem(
+                               $this->mCode, 'magicWords', $mw->mId );
                }
 
                if ( !is_array( $rawEntry ) ) {
-                       error_log( "\"$rawEntry\" is not a valid magic thingie for \"$mw->mId\"" );
+                       wfWarn( "\"$rawEntry\" is not a valid magic word for \"$mw->mId\"" );
                } else {
                        $mw->mCaseSensitive = $rawEntry[0];
                        $mw->mSynonyms = array_slice( $rawEntry, 1 );
@@ -2103,17 +3187,11 @@ class Language {
 
        /**
         * Add magic words to the extension array
+        *
+        * @param array $newWords
         */
        function addMagicWordsByLang( $newWords ) {
-               $code = $this->getCode();
-               $fallbackChain = array();
-               while ( $code && !in_array( $code, $fallbackChain ) ) {
-                       $fallbackChain[] = $code;
-                       $code = self::getFallbackFor( $code );
-               }
-               if ( !in_array( 'en', $fallbackChain ) ) {
-                       $fallbackChain[] = 'en';
-               }
+               $fallbackChain = $this->getFallbackLanguages();
                $fallbackChain = array_reverse( $fallbackChain );
                foreach ( $fallbackChain as $code ) {
                        if ( isset( $newWords[$code] ) ) {
@@ -2124,7 +3202,8 @@ class Language {
 
        /**
         * Get special page names, as an associative array
-        *   case folded alias => real name
+        *   canonical name => array of valid names, including aliases
+        * @return array
         */
        function getSpecialPageAliases() {
                // Cache aliases because it may be slow to load them
@@ -2132,8 +3211,8 @@ class Language {
                        // Initialise array
                        $this->mExtendedSpecialPageAliases =
                                self::$dataCache->getItem( $this->mCode, 'specialPageAliases' );
-                       wfRunHooks( 'LanguageGetSpecialPageAliases',
-                               array( &$this->mExtendedSpecialPageAliases, $this->getCode() ) );
+                       Hooks::run( 'LanguageGetSpecialPageAliases',
+                               [ &$this->mExtendedSpecialPageAliases, $this->getCode() ] );
                }
 
                return $this->mExtendedSpecialPageAliases;
@@ -2142,38 +3221,36 @@ class Language {
        /**
         * Italic is unsuitable for some languages
         *
-        * @param $text String: the text to be emphasized.
+        * @param string $text The text to be emphasized.
         * @return string
         */
        function emphasize( $text ) {
                return "<em>$text</em>";
        }
 
-        /**
-         * Normally we output all numbers in plain en_US style, that is
-         * 293,291.235 for twohundredninetythreethousand-twohundredninetyone
-         * point twohundredthirtyfive. However this is not sutable for all
-         * languages, some such as Pakaran want ੨੯੩,੨੯੫.੨੩੫ and others such as
-         * Icelandic just want to use commas instead of dots, and dots instead
-         * of commas like "293.291,235".
-         *
-         * An example of this function being called:
-         * <code>
-         * wfMsg( 'message', $wgLang->formatNum( $num ) )
-         * </code>
-         *
-         * See LanguageGu.php for the Gujarati implementation and
-         * $separatorTransformTable on MessageIs.php for
-         * the , => . and . => , implementation.
-         *
-         * @todo check if it's viable to use localeconv() for the decimal
-         *       separator thing.
-         * @param $number Mixed: the string to be formatted, should be an integer
-         *        or a floating point number.
-         * @param $nocommafy Bool: set to true for special numbers like dates
-         * @return string
-         */
-       function formatNum( $number, $nocommafy = false ) {
+       /**
+        * Normally we output all numbers in plain en_US style, that is
+        * 293,291.235 for twohundredninetythreethousand-twohundredninetyone
+        * point twohundredthirtyfive. However this is not suitable for all
+        * languages, some such as Bengali (bn) want ২,৯৩,২৯১.২৩৫ and others such as
+        * Icelandic just want to use commas instead of dots, and dots instead
+        * of commas like "293.291,235".
+        *
+        * An example of this function being called:
+        * <code>
+        * wfMessage( 'message' )->numParams( $num )->text()
+        * </code>
+        *
+        * See $separatorTransformTable on MessageIs.php for
+        * the , => . and . => , implementation.
+        *
+        * @todo check if it's viable to use localeconv() for the decimal separator thing.
+        * @param int|float $number The string to be formatted, should be an integer
+        *   or a floating point number.
+        * @param bool $nocommafy Set to true for special numbers like dates
+        * @return string
+        */
+       public function formatNum( $number, $nocommafy = false ) {
                global $wgTranslateNumerals;
                if ( !$nocommafy ) {
                        $number = $this->commafy( $number );
@@ -2193,35 +3270,113 @@ class Language {
                return $number;
        }
 
-       function parseFormattedNumber( $number ) {
+       /**
+        * Front-end for non-commafied formatNum
+        *
+        * @param int|float $number The string to be formatted, should be an integer
+        *        or a floating point number.
+        * @since 1.21
+        * @return string
+        */
+       public function formatNumNoSeparators( $number ) {
+               return $this->formatNum( $number, true );
+       }
+
+       /**
+        * @param string $number
+        * @return string
+        */
+       public function parseFormattedNumber( $number ) {
                $s = $this->digitTransformTable();
                if ( $s ) {
+                       // eliminate empty array values such as ''. (T66347)
+                       $s = array_filter( $s );
                        $number = strtr( $number, array_flip( $s ) );
                }
 
                $s = $this->separatorTransformTable();
                if ( $s ) {
+                       // eliminate empty array values such as ''. (T66347)
+                       $s = array_filter( $s );
                        $number = strtr( $number, array_flip( $s ) );
                }
 
-               $number = strtr( $number, array( ',' => '' ) );
+               $number = strtr( $number, [ ',' => '' ] );
                return $number;
        }
 
        /**
         * Adds commas to a given number
-        *
-        * @param $_ mixed
+        * @since 1.19
+        * @param mixed $number
         * @return string
         */
-       function commafy( $_ ) {
-               return strrev( (string)preg_replace( '/(\d{3})(?=\d)(?!\d*\.)/', '$1,', strrev( $_ ) ) );
+       function commafy( $number ) {
+               $digitGroupingPattern = $this->digitGroupingPattern();
+               if ( $number === null ) {
+                       return '';
+               }
+
+               if ( !$digitGroupingPattern || $digitGroupingPattern === "###,###,###" ) {
+                       // default grouping is at thousands,  use the same for ###,###,### pattern too.
+                       return strrev( (string)preg_replace( '/(\d{3})(?=\d)(?!\d*\.)/', '$1,', strrev( $number ) ) );
+               } else {
+                       // Ref: http://cldr.unicode.org/translation/number-patterns
+                       $sign = "";
+                       if ( intval( $number ) < 0 ) {
+                               // For negative numbers apply the algorithm like positive number and add sign.
+                               $sign = "-";
+                               $number = substr( $number, 1 );
+                       }
+                       $integerPart = [];
+                       $decimalPart = [];
+                       $numMatches = preg_match_all( "/(#+)/", $digitGroupingPattern, $matches );
+                       preg_match( "/\d+/", $number, $integerPart );
+                       preg_match( "/\.\d*/", $number, $decimalPart );
+                       $groupedNumber = ( count( $decimalPart ) > 0 ) ? $decimalPart[0] : "";
+                       if ( $groupedNumber === $number ) {
+                               // the string does not have any number part. Eg: .12345
+                               return $sign . $groupedNumber;
+                       }
+                       $start = $end = ( $integerPart ) ? strlen( $integerPart[0] ) : 0;
+                       while ( $start > 0 ) {
+                               $match = $matches[0][$numMatches - 1];
+                               $matchLen = strlen( $match );
+                               $start = $end - $matchLen;
+                               if ( $start < 0 ) {
+                                       $start = 0;
+                               }
+                               $groupedNumber = substr( $number, $start, $end - $start ) . $groupedNumber;
+                               $end = $start;
+                               if ( $numMatches > 1 ) {
+                                       // use the last pattern for the rest of the number
+                                       $numMatches--;
+                               }
+                               if ( $start > 0 ) {
+                                       $groupedNumber = "," . $groupedNumber;
+                               }
+                       }
+                       return $sign . $groupedNumber;
+               }
        }
 
-       function digitTransformTable() {
-               return self::$dataCache->getItem( $this->mCode, 'digitTransformTable' );
+       /**
+        * @return string
+        */
+       function digitGroupingPattern() {
+               return self::$dataCache->getItem( $this->mCode, 'digitGroupingPattern' );
        }
 
+       /**
+        * @return array
+        */
+       function digitTransformTable() {
+               return self::$dataCache->getItem( $this->mCode, 'digitTransformTable' );
+       }
+
+       /**
+        * @return array
+        */
        function separatorTransformTable() {
                return self::$dataCache->getItem( $this->mCode, 'separatorTransformTable' );
        }
@@ -2230,73 +3385,69 @@ class Language {
         * Take a list of strings and build a locale-friendly comma-separated
         * list, using the local comma-separator message.
         * The last two strings are chained with an "and".
+        * NOTE: This function will only work with standard numeric array keys (0, 1, 2…)
         *
-        * @param $l Array
+        * @param string[] $l
         * @return string
         */
-       function listToText( $l ) {
-               $s = '';
+       function listToText( array $l ) {
                $m = count( $l ) - 1;
-               if ( $m == 1 ) {
-                       return $l[0] . $this->getMessageFromDB( 'and' ) . $this->getMessageFromDB( 'word-separator' ) . $l[1];
-               } else {
-                       for ( $i = $m; $i >= 0; $i-- ) {
-                               if ( $i == $m ) {
-                                       $s = $l[$i];
-                               } else if ( $i == $m - 1 ) {
-                                       $s = $l[$i] . $this->getMessageFromDB( 'and' ) . $this->getMessageFromDB( 'word-separator' ) . $s;
-                               } else {
-                                       $s = $l[$i] . $this->getMessageFromDB( 'comma-separator' ) . $s;
-                               }
+               if ( $m < 0 ) {
+                       return '';
+               }
+               if ( $m > 0 ) {
+                       $and = $this->msg( 'and' )->escaped();
+                       $space = $this->msg( 'word-separator' )->escaped();
+                       if ( $m > 1 ) {
+                               $comma = $this->msg( 'comma-separator' )->escaped();
                        }
-                       return $s;
                }
+               $s = $l[$m];
+               for ( $i = $m - 1; $i >= 0; $i-- ) {
+                       if ( $i == $m - 1 ) {
+                               $s = $l[$i] . $and . $space . $s;
+                       } else {
+                               $s = $l[$i] . $comma . $s;
+                       }
+               }
+               return $s;
        }
 
        /**
         * Take a list of strings and build a locale-friendly comma-separated
         * list, using the local comma-separator message.
-        * @param $list array of strings to put in a comma list
+        * @param string[] $list Array of strings to put in a comma list
         * @return string
         */
-       function commaList( $list ) {
+       function commaList( array $list ) {
                return implode(
-                       $list,
-                       wfMsgExt(
-                               'comma-separator',
-                               array( 'parsemag', 'escapenoentities', 'language' => $this )
-                       )
+                       wfMessage( 'comma-separator' )->inLanguage( $this )->escaped(),
+                       $list
                );
        }
 
        /**
         * Take a list of strings and build a locale-friendly semicolon-separated
         * list, using the local semicolon-separator message.
-        * @param $list array of strings to put in a semicolon list
+        * @param string[] $list Array of strings to put in a semicolon list
         * @return string
         */
-       function semicolonList( $list ) {
+       function semicolonList( array $list ) {
                return implode(
-                       $list,
-                       wfMsgExt(
-                               'semicolon-separator',
-                               array( 'parsemag', 'escapenoentities', 'language' => $this )
-                       )
+                       wfMessage( 'semicolon-separator' )->inLanguage( $this )->escaped(),
+                       $list
                );
        }
 
        /**
         * Same as commaList, but separate it with the pipe instead.
-        * @param $list array of strings to put in a pipe list
+        * @param string[] $list Array of strings to put in a pipe list
         * @return string
         */
-       function pipeList( $list ) {
+       function pipeList( array $list ) {
                return implode(
-                       $list,
-                       wfMsgExt(
-                               'pipe-separator',
-                               array( 'escapenoentities', 'language' => $this )
-                       )
+                       wfMessage( 'pipe-separator' )->inLanguage( $this )->escaped(),
+                       $list
                );
        }
 
@@ -2310,33 +3461,48 @@ class Language {
         *
         * If $length is negative, the string will be truncated from the beginning
         *
-        * @param $string String to truncate
-        * @param $length Int: maximum length (excluding ellipses)
-        * @param $ellipsis String to append to the truncated text
+        * @param string $string String to truncate
+        * @param int $length Maximum length (including ellipses)
+        * @param string $ellipsis String to append to the truncated text
+        * @param bool $adjustLength Subtract length of ellipsis from $length.
+        *      $adjustLength was introduced in 1.18, before that behaved as if false.
         * @return string
         */
-       function truncate( $string, $length, $ellipsis = '...' ) {
+       function truncate( $string, $length, $ellipsis = '...', $adjustLength = true ) {
                # Use the localized ellipsis character
                if ( $ellipsis == '...' ) {
-                       $ellipsis = wfMsgExt( 'ellipsis', array( 'escapenoentities', 'language' => $this ) );
+                       $ellipsis = wfMessage( 'ellipsis' )->inLanguage( $this )->escaped();
                }
                # Check if there is no need to truncate
                if ( $length == 0 ) {
-                       return $ellipsis;
+                       return $ellipsis; // convention
                } elseif ( strlen( $string ) <= abs( $length ) ) {
-                       return $string;
+                       return $string; // no need to truncate
                }
                $stringOriginal = $string;
-               if ( $length > 0 ) {
-                       $string = substr( $string, 0, $length ); // xyz...
-                       $string = $this->removeBadCharLast( $string );
-                       $string = $string . $ellipsis;
+               # If ellipsis length is >= $length then we can't apply $adjustLength
+               if ( $adjustLength && strlen( $ellipsis ) >= abs( $length ) ) {
+                       $string = $ellipsis; // this can be slightly unexpected
+               # Otherwise, truncate and add ellipsis...
                } else {
-                       $string = substr( $string, $length ); // ...xyz
-                       $string = $this->removeBadCharFirst( $string );
-                       $string = $ellipsis . $string;
+                       $eLength = $adjustLength ? strlen( $ellipsis ) : 0;
+                       if ( $length > 0 ) {
+                               $length -= $eLength;
+                               $string = substr( $string, 0, $length ); // xyz...
+                               $string = $this->removeBadCharLast( $string );
+                               $string = rtrim( $string );
+                               $string = $string . $ellipsis;
+                       } else {
+                               $length += $eLength;
+                               $string = substr( $string, $length ); // ...xyz
+                               $string = $this->removeBadCharFirst( $string );
+                               $string = ltrim( $string );
+                               $string = $ellipsis . $string;
+                       }
                }
-               # Do not truncate if the ellipsis makes the string longer/equal (bug 22181)
+               # Do not truncate if the ellipsis makes the string longer/equal (T24181).
+               # This check is *not* redundant if $adjustLength, due to the single case where
+               # LEN($ellipsis) > ABS($limit arg); $stringOriginal could be shorter than $string.
                if ( strlen( $string ) < strlen( $stringOriginal ) ) {
                        return $string;
                } else {
@@ -2348,21 +3514,24 @@ class Language {
         * Remove bytes that represent an incomplete Unicode character
         * at the end of string (e.g. bytes of the char are missing)
         *
-        * @param $string String
+        * @param string $string
         * @return string
         */
        protected function removeBadCharLast( $string ) {
-               $char = ord( $string[strlen( $string ) - 1] );
-               $m = array();
-               if ( $char >= 0xc0 ) {
-                       # We got the first byte only of a multibyte char; remove it.
-                       $string = substr( $string, 0, -1 );
-               } elseif ( $char >= 0x80 &&
-                     preg_match( '/^(.*)(?:[\xe0-\xef][\x80-\xbf]|' .
-                                 '[\xf0-\xf7][\x80-\xbf]{1,2})$/', $string, $m ) )
-               {
-                       # We chopped in the middle of a character; remove it
-                       $string = $m[1];
+               if ( $string != '' ) {
+                       $char = ord( $string[strlen( $string ) - 1] );
+                       $m = [];
+                       if ( $char >= 0xc0 ) {
+                               # We got the first byte only of a multibyte char; remove it.
+                               $string = substr( $string, 0, -1 );
+                       } elseif ( $char >= 0x80 &&
+                               // Use the /s modifier (PCRE_DOTALL) so (.*) also matches newlines
+                               preg_match( '/^(.*)(?:[\xe0-\xef][\x80-\xbf]|' .
+                                       '[\xf0-\xf7][\x80-\xbf]{1,2})$/s', $string, $m )
+                       ) {
+                               # We chopped in the middle of a character; remove it
+                               $string = $m[1];
+                       }
                }
                return $string;
        }
@@ -2371,53 +3540,83 @@ class Language {
         * Remove bytes that represent an incomplete Unicode character
         * at the start of string (e.g. bytes of the char are missing)
         *
-        * @param $string String
+        * @param string $string
         * @return string
         */
        protected function removeBadCharFirst( $string ) {
-               $char = ord( $string[0] );
-               if ( $char >= 0x80 && $char < 0xc0 ) {
-                       # We chopped in the middle of a character; remove the whole thing
-                       $string = preg_replace( '/^[\x80-\xbf]+/', '', $string );
+               if ( $string != '' ) {
+                       $char = ord( $string[0] );
+                       if ( $char >= 0x80 && $char < 0xc0 ) {
+                               # We chopped in the middle of a character; remove the whole thing
+                               $string = preg_replace( '/^[\x80-\xbf]+/', '', $string );
+                       }
                }
                return $string;
        }
 
-       /*
+       /**
         * Truncate a string of valid HTML to a specified length in bytes,
         * appending an optional string (e.g. for ellipses), and return valid HTML
         *
         * This is only intended for styled/linked text, such as HTML with
-        * tags like <span> and <a>, were the tags are self-contained (valid HTML)
+        * tags like <span> and <a>, were the tags are self-contained (valid HTML).
+        * Also, this will not detect things like "display:none" CSS.
         *
-        * Note: tries to fix broken HTML with MWTidy
+        * Note: since 1.18 you do not need to leave extra room in $length for ellipses.
         *
         * @param string $text HTML string to truncate
-        * @param int $length (zero/positive) Maximum length (excluding ellipses)
+        * @param int $length (zero/positive) Maximum length (including ellipses)
         * @param string $ellipsis String to append to the truncated text
-        * @returns string
+        * @return string
         */
        function truncateHtml( $text, $length, $ellipsis = '...' ) {
                # Use the localized ellipsis character
                if ( $ellipsis == '...' ) {
-                       $ellipsis = wfMsgExt( 'ellipsis', array( 'escapenoentities', 'language' => $this ) );
+                       $ellipsis = wfMessage( 'ellipsis' )->inLanguage( $this )->escaped();
                }
-               # Check if there is no need to truncate
+               # Check if there is clearly no need to truncate
                if ( $length <= 0 ) {
-                       return $ellipsis; // no text shown, nothing to format
+                       return $ellipsis; // no text shown, nothing to format (convention)
                } elseif ( strlen( $text ) <= $length ) {
-                       return $text; // string short enough even *with* HTML
+                       return $text; // string short enough even *with* HTML (short-circuit)
                }
-               $text = MWTidy::tidy( $text ); // fix tags
-               $displayLen = 0; // innerHTML legth so far
+
+               $dispLen = 0; // innerHTML legth so far
                $testingEllipsis = false; // checking if ellipses will make string longer/equal?
                $tagType = 0; // 0-open, 1-close
                $bracketState = 0; // 1-tag start, 2-tag name, 0-neither
                $entityState = 0; // 0-not entity, 1-entity
-               $tag = $ret = '';
-               $openTags = array(); // open tag stack
+               $tag = $ret = ''; // accumulated tag name, accumulated result string
+               $openTags = []; // open tag stack
+               $maybeState = null; // possible truncation state
+
                $textLen = strlen( $text );
-               for ( $pos = 0; $pos < $textLen; ++$pos ) {
+               $neLength = max( 0, $length - strlen( $ellipsis ) ); // non-ellipsis len if truncated
+               for ( $pos = 0; true; ++$pos ) {
+                       # Consider truncation once the display length has reached the maximim.
+                       # We check if $dispLen > 0 to grab tags for the $neLength = 0 case.
+                       # Check that we're not in the middle of a bracket/entity...
+                       if ( $dispLen && $dispLen >= $neLength && $bracketState == 0 && !$entityState ) {
+                               if ( !$testingEllipsis ) {
+                                       $testingEllipsis = true;
+                                       # Save where we are; we will truncate here unless there turn out to
+                                       # be so few remaining characters that truncation is not necessary.
+                                       if ( !$maybeState ) { // already saved? ($neLength = 0 case)
+                                               $maybeState = [ $ret, $openTags ]; // save state
+                                       }
+                               } elseif ( $dispLen > $length && $dispLen > strlen( $ellipsis ) ) {
+                                       # String in fact does need truncation, the truncation point was OK.
+                                       list( $ret, $openTags ) = $maybeState; // reload state
+                                       $ret = $this->removeBadCharLast( $ret ); // multi-byte char fix
+                                       $ret .= $ellipsis; // add ellipsis
+                                       break;
+                               }
+                       }
+                       if ( $pos >= $textLen ) {
+                               break; // extra iteration just for above checks
+                       }
+
+                       # Read the next char...
                        $ch = $text[$pos];
                        $lastCh = $pos ? $text[$pos - 1] : '';
                        $ret .= $ch; // add to result string
@@ -2448,41 +3647,26 @@ class Language {
                                if ( $entityState ) {
                                        if ( $ch == ';' ) {
                                                $entityState = 0;
-                                               $displayLen++; // entity is one displayed char
+                                               $dispLen++; // entity is one displayed char
                                        }
                                } else {
+                                       if ( $neLength == 0 && !$maybeState ) {
+                                               // Save state without $ch. We want to *hit* the first
+                                               // display char (to get tags) but not *use* it if truncating.
+                                               $maybeState = [ substr( $ret, 0, -1 ), $openTags ];
+                                       }
                                        if ( $ch == '&' ) {
                                                $entityState = 1; // entity found, (e.g. "&#160;")
                                        } else {
-                                               $displayLen++; // this char is displayed
-                                               // Add on the other display text after this...
-                                               $skipped = $this->truncate_skip(
-                                                       $ret, $text, "<>&", $pos + 1, $length - $displayLen );
-                                               $displayLen += $skipped;
+                                               $dispLen++; // this char is displayed
+                                               // Add the next $max display text chars after this in one swoop...
+                                               $max = ( $testingEllipsis ? $length : $neLength ) - $dispLen;
+                                               $skipped = $this->truncate_skip( $ret, $text, "<>&", $pos + 1, $max );
+                                               $dispLen += $skipped;
                                                $pos += $skipped;
                                        }
                                }
                        }
-                       # Consider truncation once the display length has reached the maximim.
-                       # Double-check that we're not in the middle of a bracket/entity...
-                       if ( $displayLen >= $length && $bracketState == 0 && $entityState == 0 ) {
-                               if ( !$testingEllipsis ) {
-                                       $testingEllipsis = true;
-                                       # Save where we are; we will truncate here unless
-                                       # the ellipsis actually makes the string longer.
-                                       $pOpenTags = $openTags; // save state
-                                       $pRet = $ret; // save state
-                               } elseif ( $displayLen > ( $length + strlen( $ellipsis ) ) ) {
-                                       # Ellipsis won't make string longer/equal, the truncation point was OK.
-                                       $openTags = $pOpenTags; // reload state
-                                       $ret = $this->removeBadCharLast( $pRet ); // reload state, multi-byte char fix
-                                       $ret .= $ellipsis; // add ellipsis
-                                       break;
-                               }
-                       }
-               }
-               if ( $displayLen == 0 ) {
-                       return ''; // no text shown, nothing to format
                }
                // Close the last tag if left unclosed by bad HTML
                $this->truncate_endBracket( $tag, $text[$textLen - 1], $tagType, $openTags );
@@ -2492,9 +3676,23 @@ class Language {
                return $ret;
        }
 
-       // truncateHtml() helper function
-       // like strcspn() but adds the skipped chars to $ret
-       private function truncate_skip( &$ret, $text, $search, $start, $len = -1 ) {
+       /**
+        * truncateHtml() helper function
+        * like strcspn() but adds the skipped chars to $ret
+        *
+        * @param string $ret
+        * @param string $text
+        * @param string $search
+        * @param int $start
+        * @param null|int $len
+        * @return int
+        */
+       private function truncate_skip( &$ret, $text, $search, $start, $len = null ) {
+               if ( $len === null ) {
+                       $len = -1; // -1 means "no limit" for strcspn
+               } elseif ( $len < 0 ) {
+                       $len = 0; // sanity
+               }
                $skipCount = 0;
                if ( $start < strlen( $text ) ) {
                        $skipCount = strcspn( $text, $search, $start, $len );
@@ -2503,13 +3701,13 @@ class Language {
                return $skipCount;
        }
 
-       /*
+       /**
         * truncateHtml() helper function
         * (a) push or pop $tag from $openTags as needed
         * (b) clear $tag value
-        * @param String &$tag Current HTML tag name we are looking at
+        * @param string &$tag Current HTML tag name we are looking at
         * @param int $tagType (0-open tag, 1-close tag)
-        * @param char $lastCh Character before the '>' that ended this tag
+        * @param string $lastCh Character before the '>' that ended this tag
         * @param array &$openTags Open tag stack (not accounting for $tag)
         */
        private function truncate_endBracket( &$tag, $tagType, $lastCh, &$openTags ) {
@@ -2517,7 +3715,7 @@ class Language {
                if ( $tag != '' ) {
                        if ( $tagType == 0 && $lastCh != '/' ) {
                                $openTags[] = $tag; // tag opened (didn't close itself)
-                       } else if ( $tagType == 1 ) {
+                       } elseif ( $tagType == 1 ) {
                                if ( $openTags && $tag == $openTags[count( $openTags ) - 1] ) {
                                        array_pop( $openTags ); // tag closed
                                }
@@ -2530,8 +3728,8 @@ class Language {
         * Grammatical transformations, needed for inflected languages
         * Invoked by putting {{grammar:case|word}} in a message
         *
-        * @param $word string
-        * @param $case string
+        * @param string $word
+        * @param string $case
         * @return string
         */
        function convertGrammar( $word, $case ) {
@@ -2539,16 +3737,120 @@ class Language {
                if ( isset( $wgGrammarForms[$this->getCode()][$case][$word] ) ) {
                        return $wgGrammarForms[$this->getCode()][$case][$word];
                }
+
+               $grammarTransformations = $this->getGrammarTransformations();
+
+               if ( isset( $grammarTransformations[$case] ) ) {
+                       $forms = $grammarTransformations[$case];
+
+                       // Some names of grammar rules are aliases for other rules.
+                       // In such cases the value is a string rather than object,
+                       // so load the actual rules.
+                       if ( is_string( $forms ) ) {
+                               $forms = $grammarTransformations[$forms];
+                       }
+
+                       foreach ( array_values( $forms ) as $rule ) {
+                               $form = $rule[0];
+
+                               if ( $form === '@metadata' ) {
+                                       continue;
+                               }
+
+                               $replacement = $rule[1];
+
+                               $regex = '/' . addcslashes( $form, '/' ) . '/u';
+                               $patternMatches = preg_match( $regex, $word );
+
+                               if ( $patternMatches === false ) {
+                                       wfLogWarning(
+                                               'An error occurred while processing grammar. ' .
+                                               "Word: '$word'. Regex: /$form/."
+                                       );
+                               } elseif ( $patternMatches === 1 ) {
+                                       $word = preg_replace( $regex, $replacement, $word );
+
+                                       break;
+                               }
+                       }
+               }
+
                return $word;
        }
 
+       /**
+        * Get the grammar forms for the content language
+        * @return array Array of grammar forms
+        * @since 1.20
+        */
+       function getGrammarForms() {
+               global $wgGrammarForms;
+               if ( isset( $wgGrammarForms[$this->getCode()] )
+                       && is_array( $wgGrammarForms[$this->getCode()] )
+               ) {
+                       return $wgGrammarForms[$this->getCode()];
+               }
+
+               return [];
+       }
+
+       /**
+        * Get the grammar transformations data for the language.
+        * Used like grammar forms, with {{GRAMMAR}} and cases,
+        * but uses pairs of regexes and replacements instead of code.
+        *
+        * @return array[] Array of grammar transformations.
+        * @throws MWException
+        * @since 1.28
+        */
+       public function getGrammarTransformations() {
+               $languageCode = $this->getCode();
+
+               if ( self::$grammarTransformations === null ) {
+                       self::$grammarTransformations = new MapCacheLRU( 10 );
+               }
+
+               if ( self::$grammarTransformations->has( $languageCode ) ) {
+                       return self::$grammarTransformations->get( $languageCode );
+               }
+
+               $data = [];
+
+               $grammarDataFile = __DIR__ . "/data/grammarTransformations/$languageCode.json";
+               if ( is_readable( $grammarDataFile ) ) {
+                       $data = FormatJson::decode(
+                               file_get_contents( $grammarDataFile ),
+                               true
+                       );
+
+                       if ( $data === null ) {
+                               throw new MWException( "Invalid grammar data for \"$languageCode\"." );
+                       }
+
+                       self::$grammarTransformations->set( $languageCode, $data );
+               }
+
+               return $data;
+       }
+
        /**
         * Provides an alternative text depending on specified gender.
-        * Usage {{gender:username|masculine|feminine|neutral}}.
+        * Usage {{gender:username|masculine|feminine|unknown}}.
         * username is optional, in which case the gender of current user is used,
         * but only in (some) interface messages; otherwise default gender is used.
-        * If second or third parameter are not specified, masculine is used.
-        * These details may be overriden per language.
+        *
+        * If no forms are given, an empty string is returned. If only one form is
+        * given, it will be returned unconditionally. These details are implied by
+        * the caller and cannot be overridden in subclasses.
+        *
+        * If three forms are given, the default is to use the third (unknown) form.
+        * If fewer than three forms are given, the default is to use the first (masculine) form.
+        * These details can be overridden in subclasses.
+        *
+        * @param string $gender
+        * @param array $forms
+        *
+        * @return string
         */
        function gender( $gender, $forms ) {
                if ( !count( $forms ) ) {
@@ -2575,25 +3877,59 @@ class Language {
         *
         * Example: {{plural:{{NUMBEROFARTICLES}}|article|articles}}
         *
-        * @param $count Integer: non-localized number
-        * @param $forms Array: different plural forms
+        * @param int $count Non-localized number
+        * @param array $forms Different plural forms
         * @return string Correct form of plural for $count in this language
         */
        function convertPlural( $count, $forms ) {
+               // Handle explicit n=pluralform cases
+               $forms = $this->handleExplicitPluralForms( $count, $forms );
+               if ( is_string( $forms ) ) {
+                       return $forms;
+               }
                if ( !count( $forms ) ) {
                        return '';
                }
-               $forms = $this->preConvertPlural( $forms, 2 );
 
-               return ( $count == 1 ) ? $forms[0] : $forms[1];
+               $pluralForm = $this->getPluralRuleIndexNumber( $count );
+               $pluralForm = min( $pluralForm, count( $forms ) - 1 );
+               return $forms[$pluralForm];
+       }
+
+       /**
+        * Handles explicit plural forms for Language::convertPlural()
+        *
+        * In {{PLURAL:$1|0=nothing|one|many}}, 0=nothing will be returned if $1 equals zero.
+        * If an explicitly defined plural form matches the $count, then
+        * string value returned, otherwise array returned for further consideration
+        * by CLDR rules or overridden convertPlural().
+        *
+        * @since 1.23
+        *
+        * @param int $count Non-localized number
+        * @param array $forms Different plural forms
+        *
+        * @return array|string
+        */
+       protected function handleExplicitPluralForms( $count, array $forms ) {
+               foreach ( $forms as $index => $form ) {
+                       if ( preg_match( '/\d+=/i', $form ) ) {
+                               $pos = strpos( $form, '=' );
+                               if ( substr( $form, 0, $pos ) === (string)$count ) {
+                                       return substr( $form, $pos + 1 );
+                               }
+                               unset( $forms[$index] );
+                       }
+               }
+               return array_values( $forms );
        }
 
        /**
         * Checks that convertPlural was given an array and pads it to requested
-        * amound of forms by copying the last one.
+        * amount of forms by copying the last one.
         *
-        * @param $count Integer: How many forms should there be at least
-        * @param $forms Array of forms given to convertPlural
+        * @param array $forms Array of forms given to convertPlural
+        * @param int $count How many forms should there be at least
         * @return array Padded array of forms or an exception if not an array
         */
        protected function preConvertPlural( /* Array */ $forms, $count ) {
@@ -2604,111 +3940,222 @@ class Language {
        }
 
        /**
-        * For translating of expiry times
-        * @param $str String: the validated block time in English
-        * @return Somehow translated block time
-        * @see LanguageFi.php for example implementation
+        * Wraps argument with unicode control characters for directionality safety
+        *
+        * This solves the problem where directionality-neutral characters at the edge of
+        * the argument string get interpreted with the wrong directionality from the
+        * enclosing context, giving renderings that look corrupted like "(Ben_(WMF".
+        *
+        * The wrapping is LRE...PDF or RLE...PDF, depending on the detected
+        * directionality of the argument string, using the BIDI algorithm's own "First
+        * strong directional codepoint" rule. Essentially, this works round the fact that
+        * there is no embedding equivalent of U+2068 FSI (isolation with heuristic
+        * direction inference). The latter is cleaner but still not widely supported.
+        *
+        * @param string $text Text to wrap
+        * @return string Text, wrapped in LRE...PDF or RLE...PDF or nothing
         */
-       function translateBlockExpiry( $str ) {
-               $scBlockExpiryOptions = $this->getMessageFromDB( 'ipboptions' );
-
-               if ( $scBlockExpiryOptions == '-' ) {
-                       return $str;
+       public function embedBidi( $text = '' ) {
+               $dir = self::strongDirFromContent( $text );
+               if ( $dir === 'ltr' ) {
+                       // Wrap in LEFT-TO-RIGHT EMBEDDING ... POP DIRECTIONAL FORMATTING
+                       return self::$lre . $text . self::$pdf;
+               }
+               if ( $dir === 'rtl' ) {
+                       // Wrap in RIGHT-TO-LEFT EMBEDDING ... POP DIRECTIONAL FORMATTING
+                       return self::$rle . $text . self::$pdf;
                }
+               // No strong directionality: do not wrap
+               return $text;
+       }
 
-               foreach ( explode( ',', $scBlockExpiryOptions ) as $option ) {
-                       if ( strpos( $option, ':' ) === false ) {
-                               continue;
-                       }
-                       list( $show, $value ) = explode( ':', $option );
+       /**
+        * @todo Maybe translate block durations.  Note that this function is somewhat misnamed: it
+        * deals with translating the *duration* ("1 week", "4 days", etc), not the expiry time
+        * (which is an absolute timestamp). Please note: do NOT add this blindly, as it is used
+        * on old expiry lengths recorded in log entries. You'd need to provide the start date to
+        * match up with it.
+        *
+        * @param string $str The validated block duration in English
+        * @param User $user User object to use timezone from or null for $wgUser
+        * @param int $now Current timestamp, for formatting relative block durations
+        * @return string Somehow translated block duration
+        * @see LanguageFi.php for example implementation
+        */
+       function translateBlockExpiry( $str, User $user = null, $now = 0 ) {
+               $duration = SpecialBlock::getSuggestedDurations( $this );
+               foreach ( $duration as $show => $value ) {
                        if ( strcmp( $str, $value ) == 0 ) {
                                return htmlspecialchars( trim( $show ) );
                        }
                }
 
-               return $str;
+               if ( wfIsInfinity( $str ) ) {
+                       foreach ( $duration as $show => $value ) {
+                               if ( wfIsInfinity( $value ) ) {
+                                       return htmlspecialchars( trim( $show ) );
+                               }
+                       }
+               }
+
+               // If all else fails, return a standard duration or timestamp description.
+               $time = strtotime( $str, $now );
+               if ( $time === false ) { // Unknown format. Return it as-is in case.
+                       return $str;
+               } elseif ( $time !== strtotime( $str, $now + 1 ) ) { // It's a relative timestamp.
+                       // The result differs based on current time, so the difference
+                       // is a fixed duration length.
+                       return $this->formatDuration( $time - $now );
+               } else { // It's an absolute timestamp.
+                       if ( $time === 0 ) {
+                               // wfTimestamp() handles 0 as current time instead of epoch.
+                               $time = '19700101000000';
+                       }
+                       if ( $user ) {
+                               return $this->userTimeAndDate( $time, $user );
+                       }
+                       return $this->timeanddate( $time );
+               }
        }
 
        /**
         * languages like Chinese need to be segmented in order for the diff
         * to be of any use
         *
-        * @param $text String
-        * @return String
+        * @param string $text
+        * @return string
         */
-       function segmentForDiff( $text ) {
+       public function segmentForDiff( $text ) {
                return $text;
        }
 
        /**
         * and unsegment to show the result
         *
-        * @param $text String
-        * @return String
+        * @param string $text
+        * @return string
         */
-       function unsegmentForDiff( $text ) {
+       public function unsegmentForDiff( $text ) {
                return $text;
        }
 
-       # convert text to all supported variants
-       function autoConvertToAllVariants( $text ) {
+       /**
+        * Return the LanguageConverter used in the Language
+        *
+        * @since 1.19
+        * @return LanguageConverter
+        */
+       public function getConverter() {
+               return $this->mConverter;
+       }
+
+       /**
+        * convert text to all supported variants
+        *
+        * @param string $text
+        * @return array
+        */
+       public function autoConvertToAllVariants( $text ) {
                return $this->mConverter->autoConvertToAllVariants( $text );
        }
 
-       # convert text to different variants of a language.
-       function convert( $text ) {
+       /**
+        * convert text to different variants of a language.
+        *
+        * @param string $text
+        * @return string
+        */
+       public function convert( $text ) {
                return $this->mConverter->convert( $text );
        }
 
-       # Convert a Title object to a string in the preferred variant
-       function convertTitle( $title ) {
+       /**
+        * Convert a Title object to a string in the preferred variant
+        *
+        * @param Title $title
+        * @return string
+        */
+       public function convertTitle( $title ) {
                return $this->mConverter->convertTitle( $title );
        }
 
-       # Check if this is a language with variants
-       function hasVariants() {
-               return sizeof( $this->getVariants() ) > 1;
+       /**
+        * Convert a namespace index to a string in the preferred variant
+        *
+        * @param int $ns
+        * @return string
+        */
+       public function convertNamespace( $ns ) {
+               return $this->mConverter->convertNamespace( $ns );
        }
 
-       # Put custom tags (e.g. -{ }-) around math to prevent conversion
-       function armourMath( $text ) {
-               return $this->mConverter->armourMath( $text );
+       /**
+        * Check if this is a language with variants
+        *
+        * @return bool
+        */
+       public function hasVariants() {
+               return count( $this->getVariants() ) > 1;
+       }
+
+       /**
+        * Check if the language has the specific variant
+        *
+        * @since 1.19
+        * @param string $variant
+        * @return bool
+        */
+       public function hasVariant( $variant ) {
+               return (bool)$this->mConverter->validateVariant( $variant );
        }
 
        /**
         * Perform output conversion on a string, and encode for safe HTML output.
-        * @param $text String text to be converted
-        * @param $isTitle Bool whether this conversion is for the article title
+        * @param string $text Text to be converted
+        * @param bool $isTitle Whether this conversion is for the article title
         * @return string
         * @todo this should get integrated somewhere sane
         */
-       function convertHtml( $text, $isTitle = false ) {
+       public function convertHtml( $text, $isTitle = false ) {
                return htmlspecialchars( $this->convert( $text, $isTitle ) );
        }
 
-       function convertCategoryKey( $key ) {
+       /**
+        * @param string $key
+        * @return string
+        */
+       public function convertCategoryKey( $key ) {
                return $this->mConverter->convertCategoryKey( $key );
        }
 
        /**
-        * Get the list of variants supported by this langauge
+        * Get the list of variants supported by this language
         * see sample implementation in LanguageZh.php
         *
-        * @return array an array of language codes
+        * @return string[] An array of language codes
         */
-       function getVariants() {
+       public function getVariants() {
                return $this->mConverter->getVariants();
        }
 
-       function getPreferredVariant() {
+       /**
+        * @return string
+        */
+       public function getPreferredVariant() {
                return $this->mConverter->getPreferredVariant();
        }
-       
-       function getDefaultVariant() {
+
+       /**
+        * @return string
+        */
+       public function getDefaultVariant() {
                return $this->mConverter->getDefaultVariant();
        }
-       
-       function getURLVariant() {
+
+       /**
+        * @return string
+        */
+       public function getURLVariant() {
                return $this->mConverter->getURLVariant();
        }
 
@@ -2717,28 +4164,17 @@ class Language {
         * 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 $link String: the name of the link
-        * @param $nt Mixed: the title object of the link
-        * @param $ignoreOtherCond Boolean: to disable other conditions when
-        *      we need to transclude a template or update a category's link
-        * @return null the input parameters may be modified upon return
+        * @param string &$link The name of the link
+        * @param Title &$nt The title object of the link
+        * @param bool $ignoreOtherCond To disable other conditions when
+        *   we need to transclude a template or update a category's link
         */
-       function findVariantLink( &$link, &$nt, $ignoreOtherCond = false ) {
+       public function findVariantLink( &$link, &$nt, $ignoreOtherCond = false ) {
                $this->mConverter->findVariantLink( $link, $nt, $ignoreOtherCond );
        }
 
-       /**
-        * If a language supports multiple variants, converts text
-        * into an array of all possible variants of the text:
-        *  'variant' => text in that variant
-        *
-        * @deprecated Use autoConvertToAllVariants()
-        */
-       function convertLinkToAllVariants( $text ) {
-               return $this->mConverter->convertLinkToAllVariants( $text );
-       }
-
        /**
         * returns language specific options used by User::getPageRenderHash()
         * for example, the preferred language variant
@@ -2756,20 +4192,39 @@ class Language {
         *
         * @return string
         */
-       function getParsedTitle() {
+       public function getParsedTitle() {
                return $this->mConverter->getParsedTitle();
        }
 
        /**
-        * Enclose a string with the "no conversion" tag. This is used by
-        * various functions in the Parser
+        * Refresh the cache of conversion tables when
+        * MediaWiki:Conversiontable* is updated.
         *
-        * @param $text String: text to be tagged for no conversion
-        * @param $noParse
-        * @return string the tagged text
+        * @param Title $title The Title of the page being updated
         */
-       function markNoConversion( $text, $noParse = false ) {
-               return $this->mConverter->markNoConversion( $text, $noParse );
+       public function updateConversionTable( Title $title ) {
+               $this->mConverter->updateConversionTable( $title );
+       }
+
+       /**
+        * Prepare external link text for conversion. When the text is
+        * a URL, it shouldn't be converted, and it'll be wrapped in
+        * the "raw" tag (-{R| }-) to prevent conversion.
+        *
+        * This function is called "markNoConversion" for historical
+        * reasons.
+        *
+        * @param string $text Text to be used for external link
+        * @param bool $noParse Wrap it without confirming it's a real URL first
+        * @return string The tagged text
+        */
+       public function markNoConversion( $text, $noParse = false ) {
+               // Excluding protocal-relative URLs may avoid many false positives.
+               if ( $noParse || preg_match( '/^(?:' . wfUrlProtocolsWithoutProtRel() . ')/', $text ) ) {
+                       return $this->mConverter->markNoConversion( $text );
+               } else {
+                       return $text;
+               }
        }
 
        /**
@@ -2778,51 +4233,105 @@ class Language {
         *
         * @return string
         */
-       function linkTrail() {
+       public function linkTrail() {
                return self::$dataCache->getItem( $this->mCode, 'linkTrail' );
        }
 
-       function getLangObj() {
-               return $this;
+       /**
+        * A regular expression character set to match legal word-prefixing
+        * characters which should be merged onto a link of the form foo[[bar]].
+        *
+        * @return string
+        */
+       public function linkPrefixCharset() {
+               return self::$dataCache->getItem( $this->mCode, 'linkPrefixCharset' );
        }
 
        /**
-        * Get the RFC 3066 code for this language object
+        * Get the "parent" language which has a converter to convert a "compatible" language
+        * (in another variant) to this language (eg. zh for zh-cn, but not en for en-gb).
+        *
+        * @return Language|null
+        * @since 1.22
         */
-       function getCode() {
-               return $this->mCode;
+       public function getParentLanguage() {
+               if ( $this->mParentLanguage !== false ) {
+                       return $this->mParentLanguage;
+               }
+
+               $code = explode( '-', $this->getCode() )[0];
+               if ( !in_array( $code, LanguageConverter::$languagesWithVariants ) ) {
+                       $this->mParentLanguage = null;
+                       return null;
+               }
+               $lang = self::factory( $code );
+               if ( !$lang->hasVariant( $this->getCode() ) ) {
+                       $this->mParentLanguage = null;
+                       return null;
+               }
+
+               $this->mParentLanguage = $lang;
+               return $lang;
        }
 
-       function setCode( $code ) {
-               $this->mCode = $code;
+       /**
+        * Compare with an other language object
+        *
+        * @since 1.28
+        * @param Language $lang
+        * @return bool
+        */
+       public function equals( Language $lang ) {
+               return $lang->getCode() === $this->mCode;
        }
 
        /**
-        * Get the name of a file for a certain language code
-        * @param $prefix string Prepend this to the filename
-        * @param $code string Language code
-        * @param $suffix string Append this to the filename
-        * @return string $prefix . $mangledCode . $suffix
+        * Get the internal language code for this language object
+        *
+        * NOTE: The return value of this function is NOT HTML-safe and must be escaped with
+        * htmlspecialchars() or similar
+        *
+        * @return string
         */
-       static function getFileName( $prefix = 'Language', $code, $suffix = '.php' ) {
-               // Protect against path traversal
-               if ( !Language::isValidCode( $code ) 
-                       || strcspn( $code, "/\\\000" ) !== strlen( $code ) ) 
-               {
-                       throw new MWException( "Invalid language code \"$code\"" );
+       public function getCode() {
+               return $this->mCode;
+       }
+
+       /**
+        * Get the code in BCP 47 format which we can use
+        * inside of html lang="" tags.
+        *
+        * NOTE: The return value of this function is NOT HTML-safe and must be escaped with
+        * htmlspecialchars() or similar.
+        *
+        * @since 1.19
+        * @return string
+        */
+       public function getHtmlCode() {
+               if ( is_null( $this->mHtmlCode ) ) {
+                       $this->mHtmlCode = wfBCP47( $this->getCode() );
                }
-               
-               return $prefix . str_replace( '-', '_', ucfirst( $code ) ) . $suffix;
+               return $this->mHtmlCode;
+       }
+
+       /**
+        * @param string $code
+        */
+       public function setCode( $code ) {
+               $this->mCode = $code;
+               // Ensure we don't leave incorrect cached data lying around
+               $this->mHtmlCode = null;
+               $this->mParentLanguage = false;
        }
 
        /**
         * Get the language code from a file name. Inverse of getFileName()
-        * @param $filename string $prefix . $languageCode . $suffix
-        * @param $prefix string Prefix before the language code
-        * @param $suffix string Suffix after the language code
-        * @return Language code, or false if $prefix or $suffix isn't found
+        * @param string $filename $prefix . $languageCode . $suffix
+        * @param string $prefix Prefix before the language code
+        * @param string $suffix Suffix after the language code
+        * @return string Language code, or false if $prefix or $suffix isn't found
         */
-       static function getCodeFromFileName( $filename, $prefix = 'Language', $suffix = '.php' ) {
+       public static function getCodeFromFileName( $filename, $prefix = 'Language', $suffix = '.php' ) {
                $m = null;
                preg_match( '/' . preg_quote( $prefix, '/' ) . '([A-Z][a-z_]+)' .
                        preg_quote( $suffix, '/' ) . '/', $filename, $m );
@@ -2832,43 +4341,164 @@ class Language {
                return str_replace( '_', '-', strtolower( $m[1] ) );
        }
 
-       static function getMessagesFileName( $code ) {
+       /**
+        * @param string $code
+        * @param bool $fallback Whether we're going through language fallback chain
+        * @return string Name of the language class
+        */
+       public static function classFromCode( $code, $fallback = true ) {
+               if ( $fallback && $code == 'en' ) {
+                       return 'Language';
+               } else {
+                       return 'Language' . str_replace( '-', '_', ucfirst( $code ) );
+               }
+       }
+
+       /**
+        * Get the name of a file for a certain language code
+        * @param string $prefix Prepend this to the filename
+        * @param string $code Language code
+        * @param string $suffix Append this to the filename
+        * @throws MWException
+        * @return string $prefix . $mangledCode . $suffix
+        */
+       public static function getFileName( $prefix = 'Language', $code, $suffix = '.php' ) {
+               if ( !self::isValidBuiltInCode( $code ) ) {
+                       throw new MWException( "Invalid language code \"$code\"" );
+               }
+
+               return $prefix . str_replace( '-', '_', ucfirst( $code ) ) . $suffix;
+       }
+
+       /**
+        * @param string $code
+        * @return string
+        */
+       public static function getMessagesFileName( $code ) {
                global $IP;
-               return self::getFileName( "$IP/languages/messages/Messages", $code, '.php' );
+               $file = self::getFileName( "$IP/languages/messages/Messages", $code, '.php' );
+               Hooks::run( 'Language::getMessagesFileName', [ $code, &$file ] );
+               return $file;
        }
 
-       static function getClassFileName( $code ) {
+       /**
+        * @param string $code
+        * @return string
+        * @throws MWException
+        * @since 1.23
+        */
+       public static function getJsonMessagesFileName( $code ) {
                global $IP;
-               return self::getFileName( "$IP/languages/classes/Language", $code, '.php' );
+
+               if ( !self::isValidBuiltInCode( $code ) ) {
+                       throw new MWException( "Invalid language code \"$code\"" );
+               }
+
+               return "$IP/languages/i18n/$code.json";
        }
 
        /**
-        * Get the fallback for a given language
+        * Get the first fallback for a given language.
+        *
+        * @param string $code
+        *
+        * @return bool|string
         */
-       static function getFallbackFor( $code ) {
-               if ( $code === 'en' ) {
-                       // Shortcut
-                       return false;
-               } else {
-                       return self::getLocalisationCache()->getItem( $code, 'fallback' );
+       public static function getFallbackFor( $code ) {
+               $fallbacks = self::getFallbacksFor( $code );
+               if ( $fallbacks ) {
+                       return $fallbacks[0];
+               }
+               return false;
+       }
+
+       /**
+        * Get the ordered list of fallback languages.
+        *
+        * @since 1.19
+        * @param string $code Language code
+        * @return array Non-empty array, ending in "en"
+        */
+       public static function getFallbacksFor( $code ) {
+               if ( $code === 'en' || !self::isValidBuiltInCode( $code ) ) {
+                       return [];
                }
+               // For unknown languages, fallbackSequence returns an empty array,
+               // hardcode fallback to 'en' in that case.
+               return self::getLocalisationCache()->getItem( $code, 'fallbackSequence' ) ?: [ 'en' ];
+       }
+
+       /**
+        * Get the ordered list of fallback languages, ending with the fallback
+        * language chain for the site language.
+        *
+        * @since 1.22
+        * @param string $code Language code
+        * @return array Array( fallbacks, site fallbacks )
+        */
+       public static function getFallbacksIncludingSiteLanguage( $code ) {
+               global $wgLanguageCode;
+
+               // Usually, we will only store a tiny number of fallback chains, so we
+               // keep them in static memory.
+               $cacheKey = "{$code}-{$wgLanguageCode}";
+
+               if ( !array_key_exists( $cacheKey, self::$fallbackLanguageCache ) ) {
+                       $fallbacks = self::getFallbacksFor( $code );
+
+                       // Append the site's fallback chain, including the site language itself
+                       $siteFallbacks = self::getFallbacksFor( $wgLanguageCode );
+                       array_unshift( $siteFallbacks, $wgLanguageCode );
+
+                       // Eliminate any languages already included in the chain
+                       $siteFallbacks = array_diff( $siteFallbacks, $fallbacks );
+
+                       self::$fallbackLanguageCache[$cacheKey] = [ $fallbacks, $siteFallbacks ];
+               }
+               return self::$fallbackLanguageCache[$cacheKey];
        }
 
        /**
         * Get all messages for a given language
-        * WARNING: this may take a long time
+        * WARNING: this may take a long time. If you just need all message *keys*
+        * but need the *contents* of only a few messages, consider using getMessageKeysFor().
+        *
+        * @param string $code
+        *
+        * @return array
         */
-       static function getMessagesFor( $code ) {
+       public static function getMessagesFor( $code ) {
                return self::getLocalisationCache()->getItem( $code, 'messages' );
        }
 
        /**
         * Get a message for a given language
+        *
+        * @param string $key
+        * @param string $code
+        *
+        * @return string
         */
-       static function getMessageFor( $key, $code ) {
+       public static function getMessageFor( $key, $code ) {
                return self::getLocalisationCache()->getSubitem( $code, 'messages', $key );
        }
 
+       /**
+        * Get all message keys for a given language. This is a faster alternative to
+        * array_keys( Language::getMessagesFor( $code ) )
+        *
+        * @since 1.19
+        * @param string $code Language code
+        * @return array Array of message keys (strings)
+        */
+       public static function getMessageKeysFor( $code ) {
+               return self::getLocalisationCache()->getSubitemList( $code, 'messages' );
+       }
+
+       /**
+        * @param string $talk
+        * @return mixed
+        */
        function fixVariableInNamespace( $talk ) {
                if ( strpos( $talk, '$1' ) === false ) {
                        return $talk;
@@ -2882,36 +4512,83 @@ class Language {
                # such as action=raw much more expensive than they need to be.
                # This will hopefully cover most cases.
                $talk = preg_replace_callback( '/{{grammar:(.*?)\|(.*?)}}/i',
-                       array( &$this, 'replaceGrammarInNamespace' ), $talk );
+                       [ $this, 'replaceGrammarInNamespace' ], $talk );
                return str_replace( ' ', '_', $talk );
        }
 
+       /**
+        * @param string $m
+        * @return string
+        */
        function replaceGrammarInNamespace( $m ) {
                return $this->convertGrammar( trim( $m[2] ), trim( $m[1] ) );
        }
 
-       static function getCaseMaps() {
-               static $wikiUpperChars, $wikiLowerChars;
-               if ( isset( $wikiUpperChars ) ) {
-                       return array( $wikiUpperChars, $wikiLowerChars );
+       /**
+        * Decode an expiry (block, protection, etc) which has come from the DB
+        *
+        * @param string $expiry Database expiry String
+        * @param bool|int $format True to process using language functions, or TS_ constant
+        *     to return the expiry in a given timestamp
+        * @param string $infinity If $format is not true, use this string for infinite expiry
+        * @return string
+        * @since 1.18
+        */
+       public function formatExpiry( $expiry, $format = true, $infinity = 'infinity' ) {
+               static $dbInfinity;
+               if ( $dbInfinity === null ) {
+                       $dbInfinity = wfGetDB( DB_REPLICA )->getInfinity();
                }
 
-               wfProfileIn( __METHOD__ );
-               $arr = wfGetPrecompiledData( 'Utf8Case.ser' );
-               if ( $arr === false ) {
-                       throw new MWException(
-                               "Utf8Case.ser is missing, please run \"make\" in the serialized directory\n" );
+               if ( $expiry == '' || $expiry === 'infinity' || $expiry == $dbInfinity ) {
+                       return $format === true
+                               ? $this->getMessageFromDB( 'infiniteblock' )
+                               : $infinity;
+               } else {
+                       return $format === true
+                               ? $this->timeanddate( $expiry, /* User preference timezone */ true )
+                               : wfTimestamp( $format, $expiry );
                }
-               extract( $arr );
-               wfProfileOut( __METHOD__ );
-               return array( $wikiUpperChars, $wikiLowerChars );
        }
 
-       function formatTimePeriod( $seconds ) {
+       /**
+        * Formats a time given in seconds into a string representation of that time.
+        *
+        * @param int|float $seconds
+        * @param array $format An optional argument that formats the returned string in different ways:
+        *   If $format['avoid'] === 'avoidseconds': don't show seconds if $seconds >= 1 hour,
+        *   If $format['avoid'] === 'avoidminutes': don't show seconds/minutes if $seconds > 48 hours,
+        *   If $format['noabbrevs'] is true: use 'seconds' and friends instead of 'seconds-abbrev'
+        *     and friends.
+        * @note For backwards compatibility, $format may also be one of the strings 'avoidseconds'
+        *     or 'avoidminutes'.
+        * @return string
+        */
+       function formatTimePeriod( $seconds, $format = [] ) {
+               if ( !is_array( $format ) ) {
+                       $format = [ 'avoid' => $format ]; // For backwards compatibility
+               }
+               if ( !isset( $format['avoid'] ) ) {
+                       $format['avoid'] = false;
+               }
+               if ( !isset( $format['noabbrevs'] ) ) {
+                       $format['noabbrevs'] = false;
+               }
+               $secondsMsg = wfMessage(
+                       $format['noabbrevs'] ? 'seconds' : 'seconds-abbrev' )->inLanguage( $this );
+               $minutesMsg = wfMessage(
+                       $format['noabbrevs'] ? 'minutes' : 'minutes-abbrev' )->inLanguage( $this );
+               $hoursMsg = wfMessage(
+                       $format['noabbrevs'] ? 'hours' : 'hours-abbrev' )->inLanguage( $this );
+               $daysMsg = wfMessage(
+                       $format['noabbrevs'] ? 'days' : 'days-abbrev' )->inLanguage( $this );
+
                if ( round( $seconds * 10 ) < 100 ) {
-                       return $this->formatNum( sprintf( "%.1f", round( $seconds * 10 ) / 10 ) ) . $this->getMessageFromDB( 'seconds-abbrev' );
+                       $s = $this->formatNum( sprintf( "%.1f", round( $seconds * 10 ) / 10 ) );
+                       $s = $secondsMsg->params( $s )->text();
                } elseif ( round( $seconds ) < 60 ) {
-                       return $this->formatNum( round( $seconds ) ) . $this->getMessageFromDB( 'seconds-abbrev' );
+                       $s = $this->formatNum( round( $seconds ) );
+                       $s = $secondsMsg->params( $s )->text();
                } elseif ( round( $seconds ) < 3600 ) {
                        $minutes = floor( $seconds / 60 );
                        $secondsPart = round( fmod( $seconds, 60 ) );
@@ -2919,9 +4596,10 @@ class Language {
                                $secondsPart = 0;
                                $minutes++;
                        }
-                       return $this->formatNum( $minutes ) . $this->getMessageFromDB( 'minutes-abbrev' ) . ' ' .
-                               $this->formatNum( $secondsPart ) . $this->getMessageFromDB( 'seconds-abbrev' );
-               } else {
+                       $s = $minutesMsg->params( $this->formatNum( $minutes ) )->text();
+                       $s .= ' ';
+                       $s .= $secondsMsg->params( $this->formatNum( $secondsPart ) )->text();
+               } elseif ( round( $seconds ) <= 2 * 86400 ) {
                        $hours = floor( $seconds / 3600 );
                        $minutes = floor( ( $seconds - $hours * 3600 ) / 60 );
                        $secondsPart = round( $seconds - $hours * 3600 - $minutes * 60 );
@@ -2933,64 +4611,292 @@ class Language {
                                $minutes = 0;
                                $hours++;
                        }
-                       return $this->formatNum( $hours ) . $this->getMessageFromDB( 'hours-abbrev' ) . ' ' .
-                               $this->formatNum( $minutes ) . $this->getMessageFromDB( 'minutes-abbrev' ) . ' ' .
-                               $this->formatNum( $secondsPart ) . $this->getMessageFromDB( 'seconds-abbrev' );
+                       $s = $hoursMsg->params( $this->formatNum( $hours ) )->text();
+                       $s .= ' ';
+                       $s .= $minutesMsg->params( $this->formatNum( $minutes ) )->text();
+                       if ( !in_array( $format['avoid'], [ 'avoidseconds', 'avoidminutes' ] ) ) {
+                               $s .= ' ' . $secondsMsg->params( $this->formatNum( $secondsPart ) )->text();
+                       }
+               } else {
+                       $days = floor( $seconds / 86400 );
+                       if ( $format['avoid'] === 'avoidminutes' ) {
+                               $hours = round( ( $seconds - $days * 86400 ) / 3600 );
+                               if ( $hours == 24 ) {
+                                       $hours = 0;
+                                       $days++;
+                               }
+                               $s = $daysMsg->params( $this->formatNum( $days ) )->text();
+                               $s .= ' ';
+                               $s .= $hoursMsg->params( $this->formatNum( $hours ) )->text();
+                       } elseif ( $format['avoid'] === 'avoidseconds' ) {
+                               $hours = floor( ( $seconds - $days * 86400 ) / 3600 );
+                               $minutes = round( ( $seconds - $days * 86400 - $hours * 3600 ) / 60 );
+                               if ( $minutes == 60 ) {
+                                       $minutes = 0;
+                                       $hours++;
+                               }
+                               if ( $hours == 24 ) {
+                                       $hours = 0;
+                                       $days++;
+                               }
+                               $s = $daysMsg->params( $this->formatNum( $days ) )->text();
+                               $s .= ' ';
+                               $s .= $hoursMsg->params( $this->formatNum( $hours ) )->text();
+                               $s .= ' ';
+                               $s .= $minutesMsg->params( $this->formatNum( $minutes ) )->text();
+                       } else {
+                               $s = $daysMsg->params( $this->formatNum( $days ) )->text();
+                               $s .= ' ';
+                               $s .= $this->formatTimePeriod( $seconds - $days * 86400, $format );
+                       }
                }
+               return $s;
        }
 
+       /**
+        * Format a bitrate for output, using an appropriate
+        * unit (bps, kbps, Mbps, Gbps, Tbps, Pbps, Ebps, Zbps or Ybps) according to
+        *   the magnitude in question.
+        *
+        * This use base 1000. For base 1024 use formatSize(), for another base
+        * see formatComputingNumbers().
+        *
+        * @param int $bps
+        * @return string
+        */
        function formatBitrate( $bps ) {
-               $units = array( 'bps', 'kbps', 'Mbps', 'Gbps' );
-               if ( $bps <= 0 ) {
-                       return $this->formatNum( $bps ) . $units[0];
-               }
-               $unitIndex = floor( log10( $bps ) / 3 );
-               $mantissa = $bps / pow( 1000, $unitIndex );
-               if ( $mantissa < 10 ) {
-                       $mantissa = round( $mantissa, 1 );
-               } else {
-                       $mantissa = round( $mantissa );
+               return $this->formatComputingNumbers( $bps, 1000, "bitrate-$1bits" );
+       }
+
+       /**
+        * @param int $size Size of the unit
+        * @param int $boundary Size boundary (1000, or 1024 in most cases)
+        * @param string $messageKey Message key to be uesd
+        * @return string
+        */
+       function formatComputingNumbers( $size, $boundary, $messageKey ) {
+               if ( $size <= 0 ) {
+                       return str_replace( '$1', $this->formatNum( $size ),
+                               $this->getMessageFromDB( str_replace( '$1', '', $messageKey ) )
+                       );
+               }
+               $sizes = [ '', 'kilo', 'mega', 'giga', 'tera', 'peta', 'exa', 'zeta', 'yotta' ];
+               $index = 0;
+
+               $maxIndex = count( $sizes ) - 1;
+               while ( $size >= $boundary && $index < $maxIndex ) {
+                       $index++;
+                       $size /= $boundary;
+               }
+
+               // For small sizes no decimal places necessary
+               $round = 0;
+               if ( $index > 1 ) {
+                       // For MB and bigger two decimal places are smarter
+                       $round = 2;
                }
-               return $this->formatNum( $mantissa ) . $units[$unitIndex];
+               $msg = str_replace( '$1', $sizes[$index], $messageKey );
+
+               $size = round( $size, $round );
+               $text = $this->getMessageFromDB( $msg );
+               return str_replace( '$1', $this->formatNum( $size ), $text );
        }
 
        /**
         * Format a size in bytes for output, using an appropriate
-        * unit (B, KB, MB or GB) according to the magnitude in question
+        * unit (B, KB, MB, GB, TB, PB, EB, ZB or YB) according to the magnitude in question
+        *
+        * This method use base 1024. For base 1000 use formatBitrate(), for
+        * another base see formatComputingNumbers()
         *
-        * @param $size Size to format
+        * @param int $size Size to format
         * @return string Plain text (not HTML)
         */
        function formatSize( $size ) {
-               // For small sizes no decimal places necessary
-               $round = 0;
-               if ( $size > 1024 ) {
-                       $size = $size / 1024;
-                       if ( $size > 1024 ) {
-                               $size = $size / 1024;
-                               // For MB and bigger two decimal places are smarter
-                               $round = 2;
-                               if ( $size > 1024 ) {
-                                       $size = $size / 1024;
-                                       $msg = 'size-gigabytes';
-                               } else {
-                                       $msg = 'size-megabytes';
-                               }
-                       } else {
-                               $msg = 'size-kilobytes';
-                       }
+               return $this->formatComputingNumbers( $size, 1024, "size-$1bytes" );
+       }
+
+       /**
+        * Make a list item, used by various special pages
+        *
+        * @param string $page Page link
+        * @param string $details HTML safe text between brackets
+        * @param bool $oppositedm Add the direction mark opposite to your
+        *   language, to display text properly
+        * @return HTML escaped string
+        */
+       function specialList( $page, $details, $oppositedm = true ) {
+               if ( !$details ) {
+                       return $page;
+               }
+
+               $dirmark = ( $oppositedm ? $this->getDirMark( true ) : '' ) . $this->getDirMark();
+               return
+                       $page .
+                       $dirmark .
+                       $this->msg( 'word-separator' )->escaped() .
+                       $this->msg( 'parentheses' )->rawParams( $details )->escaped();
+       }
+
+       /**
+        * Generate (prev x| next x) (20|50|100...) type links for paging
+        *
+        * @param Title $title Title object to link
+        * @param int $offset
+        * @param int $limit
+        * @param array $query Optional URL query parameter string
+        * @param bool $atend Optional param for specified if this is the last page
+        * @return string
+        */
+       public function viewPrevNext( Title $title, $offset, $limit,
+               array $query = [], $atend = false
+       ) {
+               // @todo FIXME: Why on earth this needs one message for the text and another one for tooltip?
+
+               # Make 'previous' link
+               $prev = wfMessage( 'prevn' )->inLanguage( $this )->title( $title )->numParams( $limit )->text();
+               if ( $offset > 0 ) {
+                       $plink = $this->numLink( $title, max( $offset - $limit, 0 ), $limit,
+                               $query, $prev, 'prevn-title', 'mw-prevlink' );
                } else {
-                       $msg = 'size-bytes';
+                       $plink = htmlspecialchars( $prev );
                }
-               $size = round( $size, $round );
-               $text = $this->getMessageFromDB( $msg );
-               return str_replace( '$1', $this->formatNum( $size ), $text );
+
+               # Make 'next' link
+               $next = wfMessage( 'nextn' )->inLanguage( $this )->title( $title )->numParams( $limit )->text();
+               if ( $atend ) {
+                       $nlink = htmlspecialchars( $next );
+               } else {
+                       $nlink = $this->numLink( $title, $offset + $limit, $limit,
+                               $query, $next, 'nextn-title', 'mw-nextlink' );
+               }
+
+               # Make links to set number of items per page
+               $numLinks = [];
+               foreach ( [ 20, 50, 100, 250, 500 ] as $num ) {
+                       $numLinks[] = $this->numLink( $title, $offset, $num,
+                               $query, $this->formatNum( $num ), 'shown-title', 'mw-numlink' );
+               }
+
+               return wfMessage( 'viewprevnext' )->inLanguage( $this )->title( $title
+                       )->rawParams( $plink, $nlink, $this->pipeList( $numLinks ) )->escaped();
+       }
+
+       /**
+        * Helper function for viewPrevNext() that generates links
+        *
+        * @param Title $title Title object to link
+        * @param int $offset
+        * @param int $limit
+        * @param array $query Extra query parameters
+        * @param string $link Text to use for the link; will be escaped
+        * @param string $tooltipMsg Name of the message to use as tooltip
+        * @param string $class Value of the "class" attribute of the link
+        * @return string HTML fragment
+        */
+       private function numLink( Title $title, $offset, $limit, array $query, $link,
+               $tooltipMsg, $class
+       ) {
+               $query = [ 'limit' => $limit, 'offset' => $offset ] + $query;
+               $tooltip = wfMessage( $tooltipMsg )->inLanguage( $this )->title( $title )
+                       ->numParams( $limit )->text();
+
+               return Html::element( 'a', [ 'href' => $title->getLocalURL( $query ),
+                       'title' => $tooltip, 'class' => $class ], $link );
        }
 
        /**
         * Get the conversion rule title, if any.
+        *
+        * @return string
         */
-       function getConvRuleTitle() {
+       public function getConvRuleTitle() {
                return $this->mConverter->getConvRuleTitle();
        }
+
+       /**
+        * Get the compiled plural rules for the language
+        * @since 1.20
+        * @return array Associative array with plural form, and plural rule as key-value pairs
+        */
+       public function getCompiledPluralRules() {
+               $pluralRules = self::$dataCache->getItem( strtolower( $this->mCode ), 'compiledPluralRules' );
+               $fallbacks = self::getFallbacksFor( $this->mCode );
+               if ( !$pluralRules ) {
+                       foreach ( $fallbacks as $fallbackCode ) {
+                               $pluralRules = self::$dataCache->getItem( strtolower( $fallbackCode ), 'compiledPluralRules' );
+                               if ( $pluralRules ) {
+                                       break;
+                               }
+                       }
+               }
+               return $pluralRules;
+       }
+
+       /**
+        * Get the plural rules for the language
+        * @since 1.20
+        * @return array Associative array with plural form number and plural rule as key-value pairs
+        */
+       public function getPluralRules() {
+               $pluralRules = self::$dataCache->getItem( strtolower( $this->mCode ), 'pluralRules' );
+               $fallbacks = self::getFallbacksFor( $this->mCode );
+               if ( !$pluralRules ) {
+                       foreach ( $fallbacks as $fallbackCode ) {
+                               $pluralRules = self::$dataCache->getItem( strtolower( $fallbackCode ), 'pluralRules' );
+                               if ( $pluralRules ) {
+                                       break;
+                               }
+                       }
+               }
+               return $pluralRules;
+       }
+
+       /**
+        * Get the plural rule types for the language
+        * @since 1.22
+        * @return array Associative array with plural form number and plural rule type as key-value pairs
+        */
+       public function getPluralRuleTypes() {
+               $pluralRuleTypes = self::$dataCache->getItem( strtolower( $this->mCode ), 'pluralRuleTypes' );
+               $fallbacks = self::getFallbacksFor( $this->mCode );
+               if ( !$pluralRuleTypes ) {
+                       foreach ( $fallbacks as $fallbackCode ) {
+                               $pluralRuleTypes = self::$dataCache->getItem( strtolower( $fallbackCode ), 'pluralRuleTypes' );
+                               if ( $pluralRuleTypes ) {
+                                       break;
+                               }
+                       }
+               }
+               return $pluralRuleTypes;
+       }
+
+       /**
+        * Find the index number of the plural rule appropriate for the given number
+        * @param int $number
+        * @return int The index number of the plural rule
+        */
+       public function getPluralRuleIndexNumber( $number ) {
+               $pluralRules = $this->getCompiledPluralRules();
+               $form = Evaluator::evaluateCompiled( $number, $pluralRules );
+               return $form;
+       }
+
+       /**
+        * Find the plural rule type appropriate for the given number
+        * For example, if the language is set to Arabic, getPluralType(5) should
+        * return 'few'.
+        * @since 1.22
+        * @param int $number
+        * @return string The name of the plural rule type, e.g. one, two, few, many
+        */
+       public function getPluralRuleType( $number ) {
+               $index = $this->getPluralRuleIndexNumber( $number );
+               $pluralRuleTypes = $this->getPluralRuleTypes();
+               if ( isset( $pluralRuleTypes[$index] ) ) {
+                       return $pluralRuleTypes[$index];
+               } else {
+                       return 'other';
+               }
+       }
 }