includes/cache/LocalisationCache.php

   1 <?php
   2 /**
   3  * Cache of the contents of localisation files.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 define( 'MW_LC_VERSION', 2 );
  24
  25 /**
  26  * Class for caching the contents of localisation files, Messages*.php
  27  * and *.i18n.php.
  28  *
  29  * An instance of this class is available using Language::getLocalisationCache().
  30  *
  31  * The values retrieved from here are merged, containing items from extension
  32  * files, core messages files and the language fallback sequence (e.g. zh-cn ->
  33  * zh-hans -> en ). Some common errors are corrected, for example namespace
  34  * names with spaces instead of underscores, but heavyweight processing, such
  35  * as grammatical transformation, is done by the caller.
  36  */
  37 class LocalisationCache {
  38         /** Configuration associative array */
  39         private $conf;
  40
  41         /**
  42          * True if recaching should only be done on an explicit call to recache().
  43          * Setting this reduces the overhead of cache freshness checking, which
  44          * requires doing a stat() for every extension i18n file.
  45          */
  46         private $manualRecache = false;
  47
  48         /**
  49          * True to treat all files as expired until they are regenerated by this object.
  50          */
  51         private $forceRecache = false;
  52
  53         /**
  54          * The cache data. 3-d array, where the first key is the language code,
  55          * the second key is the item key e.g. 'messages', and the third key is
  56          * an item specific subkey index. Some items are not arrays and so for those
  57          * items, there are no subkeys.
  58          */
  59         protected $data = array();
  60
  61         /**
  62          * The persistent store object. An instance of LCStore.
  63          *
  64          * @var LCStore
  65          */
  66         private $store;
  67
  68         /**
  69          * A 2-d associative array, code/key, where presence indicates that the item
  70          * is loaded. Value arbitrary.
  71          *
  72          * For split items, if set, this indicates that all of the subitems have been
  73          * loaded.
  74          */
  75         private $loadedItems = array();
  76
  77         /**
  78          * A 3-d associative array, code/key/subkey, where presence indicates that
  79          * the subitem is loaded. Only used for the split items, i.e. messages.
  80          */
  81         private $loadedSubitems = array();
  82
  83         /**
  84          * An array where presence of a key indicates that that language has been
  85          * initialised. Initialisation includes checking for cache expiry and doing
  86          * any necessary updates.
  87          */
  88         private $initialisedLangs = array();
  89
  90         /**
  91          * An array mapping non-existent pseudo-languages to fallback languages. This
  92          * is filled by initShallowFallback() when data is requested from a language
  93          * that lacks a Messages*.php file.
  94          */
  95         private $shallowFallbacks = array();
  96
  97         /**
  98          * An array where the keys are codes that have been recached by this instance.
  99          */
 100         private $recachedLangs = array();
 101
 102         /**
 103          * All item keys
 104          */
 105         static public $allKeys = array(
 106                 'fallback', 'namespaceNames', 'bookstoreList',
 107                 'magicWords', 'messages', 'rtl', 'capitalizeAllNouns', 'digitTransformTable',
 108                 'separatorTransformTable', 'fallback8bitEncoding', 'linkPrefixExtension',
 109                 'linkTrail', 'linkPrefixCharset', 'namespaceAliases',
 110                 'dateFormats', 'datePreferences', 'datePreferenceMigrationMap',
 111                 'defaultDateFormat', 'extraUserToggles', 'specialPageAliases',
 112                 'imageFiles', 'preloadedMessages', 'namespaceGenderAliases',
 113                 'digitGroupingPattern', 'pluralRules', 'pluralRuleTypes', 'compiledPluralRules',
 114         );
 115
 116         /**
 117          * Keys for items which consist of associative arrays, which may be merged
 118          * by a fallback sequence.
 119          */
 120         static public $mergeableMapKeys = array( 'messages', 'namespaceNames',
 121                 'dateFormats', 'imageFiles', 'preloadedMessages'
 122         );
 123
 124         /**
 125          * Keys for items which are a numbered array.
 126          */
 127         static public $mergeableListKeys = array( 'extraUserToggles' );
 128
 129         /**
 130          * Keys for items which contain an array of arrays of equivalent aliases
 131          * for each subitem. The aliases may be merged by a fallback sequence.
 132          */
 133         static public $mergeableAliasListKeys = array( 'specialPageAliases' );
 134
 135         /**
 136          * Keys for items which contain an associative array, and may be merged if
 137          * the primary value contains the special array key "inherit". That array
 138          * key is removed after the first merge.
 139          */
 140         static public $optionalMergeKeys = array( 'bookstoreList' );
 141
 142         /**
 143          * Keys for items that are formatted like $magicWords
 144          */
 145         static public $magicWordKeys = array( 'magicWords' );
 146
 147         /**
 148          * Keys for items where the subitems are stored in the backend separately.
 149          */
 150         static public $splitKeys = array( 'messages' );
 151
 152         /**
 153          * Keys which are loaded automatically by initLanguage()
 154          */
 155         static public $preloadedKeys = array( 'dateFormats', 'namespaceNames' );
 156
 157         /**
 158          * Associative array of cached plural rules. The key is the language code,
 159          * the value is an array of plural rules for that language.
 160          */
 161         private $pluralRules = null;
 162
 163         /**
 164          * Associative array of cached plural rule types. The key is the language
 165          * code, the value is an array of plural rule types for that language. For
 166          * example, $pluralRuleTypes['ar'] = ['zero', 'one', 'two', 'few', 'many'].
 167          * The index for each rule type matches the index for the rule in
 168          * $pluralRules, thus allowing correlation between the two. The reason we
 169          * don't just use the type names as the keys in $pluralRules is because
 170          * Language::convertPlural applies the rules based on numeric order (or
 171          * explicit numeric parameter), not based on the name of the rule type. For
 172          * example, {{plural:count|wordform1|wordform2|wordform3}}, rather than
 173          * {{plural:count|one=wordform1|two=wordform2|many=wordform3}}.
 174          */
 175         private $pluralRuleTypes = null;
 176
 177         private $mergeableKeys = null;
 178
 179         /**
 180          * Constructor.
 181          * For constructor parameters, see the documentation in DefaultSettings.php
 182          * for $wgLocalisationCacheConf.
 183          *
 184          * @param $conf Array
 185          * @throws MWException
 186          */
 187         function __construct( $conf ) {
 188                 global $wgCacheDirectory;
 189
 190                 $this->conf = $conf;
 191                 $storeConf = array();
 192                 if ( !empty( $conf['storeClass'] ) ) {
 193                         $storeClass = $conf['storeClass'];
 194                 } else {
 195                         switch ( $conf['store'] ) {
 196                                 case 'files':
 197                                 case 'file':
 198                                         $storeClass = 'LCStoreCDB';
 199                                         break;
 200                                 case 'db':
 201                                         $storeClass = 'LCStoreDB';
 202                                         break;
 203                                 case 'accel':
 204                                         $storeClass = 'LCStoreAccel';
 205                                         break;
 206                                 case 'detect':
 207                                         $storeClass = $wgCacheDirectory ? 'LCStoreCDB' : 'LCStoreDB';
 208                                         break;
 209                                 default:
 210                                         throw new MWException(
 211                                                 'Please set $wgLocalisationCacheConf[\'store\'] to something sensible.' );
 212                         }
 213                 }
 214
 215                 wfDebug( get_class( $this ) . ": using store $storeClass\n" );
 216                 if ( !empty( $conf['storeDirectory'] ) ) {
 217                         $storeConf['directory'] = $conf['storeDirectory'];
 218                 }
 219
 220                 $this->store = new $storeClass( $storeConf );
 221                 foreach ( array( 'manualRecache', 'forceRecache' ) as $var ) {
 222                         if ( isset( $conf[$var] ) ) {
 223                                 $this->$var = $conf[$var];
 224                         }
 225                 }
 226         }
 227
 228         /**
 229          * Returns true if the given key is mergeable, that is, if it is an associative
 230          * array which can be merged through a fallback sequence.
 231          * @param $key
 232          * @return bool
 233          */
 234         public function isMergeableKey( $key ) {
 235                 if ( $this->mergeableKeys === null ) {
 236                         $this->mergeableKeys = array_flip( array_merge(
 237                                 self::$mergeableMapKeys,
 238                                 self::$mergeableListKeys,
 239                                 self::$mergeableAliasListKeys,
 240                                 self::$optionalMergeKeys,
 241                                 self::$magicWordKeys
 242                         ) );
 243                 }
 244
 245                 return isset( $this->mergeableKeys[$key] );
 246         }
 247
 248         /**
 249          * Get a cache item.
 250          *
 251          * Warning: this may be slow for split items (messages), since it will
 252          * need to fetch all of the subitems from the cache individually.
 253          * @param $code
 254          * @param $key
 255          * @return mixed
 256          */
 257         public function getItem( $code, $key ) {
 258                 if ( !isset( $this->loadedItems[$code][$key] ) ) {
 259                         wfProfileIn( __METHOD__ . '-load' );
 260                         $this->loadItem( $code, $key );
 261                         wfProfileOut( __METHOD__ . '-load' );
 262                 }
 263
 264                 if ( $key === 'fallback' && isset( $this->shallowFallbacks[$code] ) ) {
 265                         return $this->shallowFallbacks[$code];
 266                 }
 267
 268                 return $this->data[$code][$key];
 269         }
 270
 271         /**
 272          * Get a subitem, for instance a single message for a given language.
 273          * @param $code
 274          * @param $key
 275          * @param $subkey
 276          * @return null
 277          */
 278         public function getSubitem( $code, $key, $subkey ) {
 279                 if ( !isset( $this->loadedSubitems[$code][$key][$subkey] ) &&
 280                         !isset( $this->loadedItems[$code][$key] )
 281                 ) {
 282                         wfProfileIn( __METHOD__ . '-load' );
 283                         $this->loadSubitem( $code, $key, $subkey );
 284                         wfProfileOut( __METHOD__ . '-load' );
 285                 }
 286
 287                 if ( isset( $this->data[$code][$key][$subkey] ) ) {
 288                         return $this->data[$code][$key][$subkey];
 289                 } else {
 290                         return null;
 291                 }
 292         }
 293
 294         /**
 295          * Get the list of subitem keys for a given item.
 296          *
 297          * This is faster than array_keys($lc->getItem(...)) for the items listed in
 298          * self::$splitKeys.
 299          *
 300          * Will return null if the item is not found, or false if the item is not an
 301          * array.
 302          * @param $code
 303          * @param $key
 304          * @return bool|null|string
 305          */
 306         public function getSubitemList( $code, $key ) {
 307                 if ( in_array( $key, self::$splitKeys ) ) {
 308                         return $this->getSubitem( $code, 'list', $key );
 309                 } else {
 310                         $item = $this->getItem( $code, $key );
 311                         if ( is_array( $item ) ) {
 312                                 return array_keys( $item );
 313                         } else {
 314                                 return false;
 315                         }
 316                 }
 317         }
 318
 319         /**
 320          * Load an item into the cache.
 321          * @param $code
 322          * @param $key
 323          */
 324         protected function loadItem( $code, $key ) {
 325                 if ( !isset( $this->initialisedLangs[$code] ) ) {
 326                         $this->initLanguage( $code );
 327                 }
 328
 329                 // Check to see if initLanguage() loaded it for us
 330                 if ( isset( $this->loadedItems[$code][$key] ) ) {
 331                         return;
 332                 }
 333
 334                 if ( isset( $this->shallowFallbacks[$code] ) ) {
 335                         $this->loadItem( $this->shallowFallbacks[$code], $key );
 336
 337                         return;
 338                 }
 339
 340                 if ( in_array( $key, self::$splitKeys ) ) {
 341                         $subkeyList = $this->getSubitem( $code, 'list', $key );
 342                         foreach ( $subkeyList as $subkey ) {
 343                                 if ( isset( $this->data[$code][$key][$subkey] ) ) {
 344                                         continue;
 345                                 }
 346                                 $this->data[$code][$key][$subkey] = $this->getSubitem( $code, $key, $subkey );
 347                         }
 348                 } else {
 349                         $this->data[$code][$key] = $this->store->get( $code, $key );
 350                 }
 351
 352                 $this->loadedItems[$code][$key] = true;
 353         }
 354
 355         /**
 356          * Load a subitem into the cache
 357          * @param $code
 358          * @param $key
 359          * @param $subkey
 360          */
 361         protected function loadSubitem( $code, $key, $subkey ) {
 362                 if ( !in_array( $key, self::$splitKeys ) ) {
 363                         $this->loadItem( $code, $key );
 364
 365                         return;
 366                 }
 367
 368                 if ( !isset( $this->initialisedLangs[$code] ) ) {
 369                         $this->initLanguage( $code );
 370                 }
 371
 372                 // Check to see if initLanguage() loaded it for us
 373                 if ( isset( $this->loadedItems[$code][$key] ) ||
 374                         isset( $this->loadedSubitems[$code][$key][$subkey] )
 375                 ) {
 376                         return;
 377                 }
 378
 379                 if ( isset( $this->shallowFallbacks[$code] ) ) {
 380                         $this->loadSubitem( $this->shallowFallbacks[$code], $key, $subkey );
 381
 382                         return;
 383                 }
 384
 385                 $value = $this->store->get( $code, "$key:$subkey" );
 386                 $this->data[$code][$key][$subkey] = $value;
 387                 $this->loadedSubitems[$code][$key][$subkey] = true;
 388         }
 389
 390         /**
 391          * Returns true if the cache identified by $code is missing or expired.
 392          *
 393          * @param string $code
 394          *
 395          * @return bool
 396          */
 397         public function isExpired( $code ) {
 398                 if ( $this->forceRecache && !isset( $this->recachedLangs[$code] ) ) {
 399                         wfDebug( __METHOD__ . "($code): forced reload\n" );
 400
 401                         return true;
 402                 }
 403
 404                 $deps = $this->store->get( $code, 'deps' );
 405                 $keys = $this->store->get( $code, 'list' );
 406                 $preload = $this->store->get( $code, 'preload' );
 407                 // Different keys may expire separately, at least in LCStoreAccel
 408                 if ( $deps === null || $keys === null || $preload === null ) {
 409                         wfDebug( __METHOD__ . "($code): cache missing, need to make one\n" );
 410
 411                         return true;
 412                 }
 413
 414                 foreach ( $deps as $dep ) {
 415                         // Because we're unserializing stuff from cache, we
 416                         // could receive objects of classes that don't exist
 417                         // anymore (e.g. uninstalled extensions)
 418                         // When this happens, always expire the cache
 419                         if ( !$dep instanceof CacheDependency || $dep->isExpired() ) {
 420                                 wfDebug( __METHOD__ . "($code): cache for $code expired due to " .
 421                                         get_class( $dep ) . "\n" );
 422
 423                                 return true;
 424                         }
 425                 }
 426
 427                 return false;
 428         }
 429
 430         /**
 431          * Initialise a language in this object. Rebuild the cache if necessary.
 432          * @param $code
 433          * @throws MWException
 434          */
 435         protected function initLanguage( $code ) {
 436                 if ( isset( $this->initialisedLangs[$code] ) ) {
 437                         return;
 438                 }
 439
 440                 $this->initialisedLangs[$code] = true;
 441
 442                 # If the code is of the wrong form for a Messages*.php file, do a shallow fallback
 443                 if ( !Language::isValidBuiltInCode( $code ) ) {
 444                         $this->initShallowFallback( $code, 'en' );
 445
 446                         return;
 447                 }
 448
 449                 # Recache the data if necessary
 450                 if ( !$this->manualRecache && $this->isExpired( $code ) ) {
 451                         if ( file_exists( Language::getMessagesFileName( $code ) ) ) {
 452                                 $this->recache( $code );
 453                         } elseif ( $code === 'en' ) {
 454                                 throw new MWException( 'MessagesEn.php is missing.' );
 455                         } else {
 456                                 $this->initShallowFallback( $code, 'en' );
 457                         }
 458
 459                         return;
 460                 }
 461
 462                 # Preload some stuff
 463                 $preload = $this->getItem( $code, 'preload' );
 464                 if ( $preload === null ) {
 465                         if ( $this->manualRecache ) {
 466                                 // No Messages*.php file. Do shallow fallback to en.
 467                                 if ( $code === 'en' ) {
 468                                         throw new MWException( 'No localisation cache found for English. ' .
 469                                                 'Please run maintenance/rebuildLocalisationCache.php.' );
 470                                 }
 471                                 $this->initShallowFallback( $code, 'en' );
 472
 473                                 return;
 474                         } else {
 475                                 throw new MWException( 'Invalid or missing localisation cache.' );
 476                         }
 477                 }
 478                 $this->data[$code] = $preload;
 479                 foreach ( $preload as $key => $item ) {
 480                         if ( in_array( $key, self::$splitKeys ) ) {
 481                                 foreach ( $item as $subkey => $subitem ) {
 482                                         $this->loadedSubitems[$code][$key][$subkey] = true;
 483                                 }
 484                         } else {
 485                                 $this->loadedItems[$code][$key] = true;
 486                         }
 487                 }
 488         }
 489
 490         /**
 491          * Create a fallback from one language to another, without creating a
 492          * complete persistent cache.
 493          * @param $primaryCode
 494          * @param $fallbackCode
 495          */
 496         public function initShallowFallback( $primaryCode, $fallbackCode ) {
 497                 $this->data[$primaryCode] =& $this->data[$fallbackCode];
 498                 $this->loadedItems[$primaryCode] =& $this->loadedItems[$fallbackCode];
 499                 $this->loadedSubitems[$primaryCode] =& $this->loadedSubitems[$fallbackCode];
 500                 $this->shallowFallbacks[$primaryCode] = $fallbackCode;
 501         }
 502
 503         /**
 504          * Read a PHP file containing localisation data.
 505          * @param $_fileName
 506          * @param $_fileType
 507          * @throws MWException
 508          * @return array
 509          */
 510         protected function readPHPFile( $_fileName, $_fileType ) {
 511                 wfProfileIn( __METHOD__ );
 512                 // Disable APC caching
 513                 $_apcEnabled = ini_set( 'apc.cache_by_default', '0' );
 514                 include $_fileName;
 515                 ini_set( 'apc.cache_by_default', $_apcEnabled );
 516
 517                 if ( $_fileType == 'core' || $_fileType == 'extension' ) {
 518                         $data = compact( self::$allKeys );
 519                 } elseif ( $_fileType == 'aliases' ) {
 520                         $data = compact( 'aliases' );
 521                 } else {
 522                         wfProfileOut( __METHOD__ );
 523                         throw new MWException( __METHOD__ . ": Invalid file type: $_fileType" );
 524                 }
 525                 wfProfileOut( __METHOD__ );
 526
 527                 return $data;
 528         }
 529
 530         /**
 531          * Get the compiled plural rules for a given language from the XML files.
 532          * @since 1.20
 533          */
 534         public function getCompiledPluralRules( $code ) {
 535                 $rules = $this->getPluralRules( $code );
 536                 if ( $rules === null ) {
 537                         return null;
 538                 }
 539                 try {
 540                         $compiledRules = CLDRPluralRuleEvaluator::compile( $rules );
 541                 } catch ( CLDRPluralRuleError $e ) {
 542                         wfDebugLog( 'l10n', $e->getMessage() . "\n" );
 543
 544                         return array();
 545                 }
 546
 547                 return $compiledRules;
 548         }
 549
 550         /**
 551          * Get the plural rules for a given language from the XML files.
 552          * Cached.
 553          * @since 1.20
 554          */
 555         public function getPluralRules( $code ) {
 556                 if ( $this->pluralRules === null ) {
 557                         $this->loadPluralFiles();
 558                 }
 559                 if ( !isset( $this->pluralRules[$code] ) ) {
 560                         return null;
 561                 } else {
 562                         return $this->pluralRules[$code];
 563                 }
 564         }
 565
 566         /**
 567          * Get the plural rule types for a given language from the XML files.
 568          * Cached.
 569          * @since 1.22
 570          */
 571         public function getPluralRuleTypes( $code ) {
 572                 if ( $this->pluralRuleTypes === null ) {
 573                         $this->loadPluralFiles();
 574                 }
 575                 if ( !isset( $this->pluralRuleTypes[$code] ) ) {
 576                         return null;
 577                 } else {
 578                         return $this->pluralRuleTypes[$code];
 579                 }
 580         }
 581
 582         /**
 583          * Load the plural XML files.
 584          */
 585         protected function loadPluralFiles() {
 586                 global $IP;
 587                 $cldrPlural = "$IP/languages/data/plurals.xml";
 588                 $mwPlural = "$IP/languages/data/plurals-mediawiki.xml";
 589                 // Load CLDR plural rules
 590                 $this->loadPluralFile( $cldrPlural );
 591                 if ( file_exists( $mwPlural ) ) {
 592                         // Override or extend
 593                         $this->loadPluralFile( $mwPlural );
 594                 }
 595         }
 596
 597         /**
 598          * Load a plural XML file with the given filename, compile the relevant
 599          * rules, and save the compiled rules in a process-local cache.
 600          */
 601         protected function loadPluralFile( $fileName ) {
 602                 $doc = new DOMDocument;
 603                 $doc->load( $fileName );
 604                 $rulesets = $doc->getElementsByTagName( "pluralRules" );
 605                 foreach ( $rulesets as $ruleset ) {
 606                         $codes = $ruleset->getAttribute( 'locales' );
 607                         $rules = array();
 608                         $ruleTypes = array();
 609                         $ruleElements = $ruleset->getElementsByTagName( "pluralRule" );
 610                         foreach ( $ruleElements as $elt ) {
 611                                 $ruleType = $elt->getAttribute( 'count' );
 612                                 if ( $ruleType === 'other' ) {
 613                                         // Don't record "other" rules, which have an empty condition
 614                                         continue;
 615                                 }
 616                                 $rules[] = $elt->nodeValue;
 617                                 $ruleTypes[] = $ruleType;
 618                         }
 619                         foreach ( explode( ' ', $codes ) as $code ) {
 620                                 $this->pluralRules[$code] = $rules;
 621                                 $this->pluralRuleTypes[$code] = $ruleTypes;
 622                         }
 623                 }
 624         }
 625
 626         /**
 627          * Read the data from the source files for a given language, and register
 628          * the relevant dependencies in the $deps array. If the localisation
 629          * exists, the data array is returned, otherwise false is returned.
 630          */
 631         protected function readSourceFilesAndRegisterDeps( $code, &$deps ) {
 632                 global $IP;
 633                 wfProfileIn( __METHOD__ );
 634
 635                 $fileName = Language::getMessagesFileName( $code );
 636                 if ( !file_exists( $fileName ) ) {
 637                         wfProfileOut( __METHOD__ );
 638
 639                         return false;
 640                 }
 641
 642                 $deps[] = new FileDependency( $fileName );
 643                 $data = $this->readPHPFile( $fileName, 'core' );
 644
 645                 # Load CLDR plural rules for JavaScript
 646                 $data['pluralRules'] = $this->getPluralRules( $code );
 647                 # And for PHP
 648                 $data['compiledPluralRules'] = $this->getCompiledPluralRules( $code );
 649                 # Load plural rule types
 650                 $data['pluralRuleTypes'] = $this->getPluralRuleTypes( $code );
 651
 652                 $deps['plurals'] = new FileDependency( "$IP/languages/data/plurals.xml" );
 653                 $deps['plurals-mw'] = new FileDependency( "$IP/languages/data/plurals-mediawiki.xml" );
 654
 655                 wfProfileOut( __METHOD__ );
 656
 657                 return $data;
 658         }
 659
 660         /**
 661          * Merge two localisation values, a primary and a fallback, overwriting the
 662          * primary value in place.
 663          * @param $key
 664          * @param $value
 665          * @param $fallbackValue
 666          */
 667         protected function mergeItem( $key, &$value, $fallbackValue ) {
 668                 if ( !is_null( $value ) ) {
 669                         if ( !is_null( $fallbackValue ) ) {
 670                                 if ( in_array( $key, self::$mergeableMapKeys ) ) {
 671                                         $value = $value + $fallbackValue;
 672                                 } elseif ( in_array( $key, self::$mergeableListKeys ) ) {
 673                                         $value = array_unique( array_merge( $fallbackValue, $value ) );
 674                                 } elseif ( in_array( $key, self::$mergeableAliasListKeys ) ) {
 675                                         $value = array_merge_recursive( $value, $fallbackValue );
 676                                 } elseif ( in_array( $key, self::$optionalMergeKeys ) ) {
 677                                         if ( !empty( $value['inherit'] ) ) {
 678                                                 $value = array_merge( $fallbackValue, $value );
 679                                         }
 680
 681                                         if ( isset( $value['inherit'] ) ) {
 682                                                 unset( $value['inherit'] );
 683                                         }
 684                                 } elseif ( in_array( $key, self::$magicWordKeys ) ) {
 685                                         $this->mergeMagicWords( $value, $fallbackValue );
 686                                 }
 687                         }
 688                 } else {
 689                         $value = $fallbackValue;
 690                 }
 691         }
 692
 693         /**
 694          * @param $value
 695          * @param $fallbackValue
 696          */
 697         protected function mergeMagicWords( &$value, $fallbackValue ) {
 698                 foreach ( $fallbackValue as $magicName => $fallbackInfo ) {
 699                         if ( !isset( $value[$magicName] ) ) {
 700                                 $value[$magicName] = $fallbackInfo;
 701                         } else {
 702                                 $oldSynonyms = array_slice( $fallbackInfo, 1 );
 703                                 $newSynonyms = array_slice( $value[$magicName], 1 );
 704                                 $synonyms = array_values( array_unique( array_merge(
 705                                         $newSynonyms, $oldSynonyms ) ) );
 706                                 $value[$magicName] = array_merge( array( $fallbackInfo[0] ), $synonyms );
 707                         }
 708                 }
 709         }
 710
 711         /**
 712          * Given an array mapping language code to localisation value, such as is
 713          * found in extension *.i18n.php files, iterate through a fallback sequence
 714          * to merge the given data with an existing primary value.
 715          *
 716          * Returns true if any data from the extension array was used, false
 717          * otherwise.
 718          * @param $codeSequence
 719          * @param $key
 720          * @param $value
 721          * @param $fallbackValue
 722          * @return bool
 723          */
 724         protected function mergeExtensionItem( $codeSequence, $key, &$value, $fallbackValue ) {
 725                 $used = false;
 726                 foreach ( $codeSequence as $code ) {
 727                         if ( isset( $fallbackValue[$code] ) ) {
 728                                 $this->mergeItem( $key, $value, $fallbackValue[$code] );
 729                                 $used = true;
 730                         }
 731                 }
 732
 733                 return $used;
 734         }
 735
 736         /**
 737          * Load localisation data for a given language for both core and extensions
 738          * and save it to the persistent cache store and the process cache
 739          * @param $code
 740          * @throws MWException
 741          */
 742         public function recache( $code ) {
 743                 global $wgExtensionMessagesFiles;
 744                 wfProfileIn( __METHOD__ );
 745
 746                 if ( !$code ) {
 747                         wfProfileOut( __METHOD__ );
 748                         throw new MWException( "Invalid language code requested" );
 749                 }
 750                 $this->recachedLangs[$code] = true;
 751
 752                 # Initial values
 753                 $initialData = array_combine(
 754                         self::$allKeys,
 755                         array_fill( 0, count( self::$allKeys ), null ) );
 756                 $coreData = $initialData;
 757                 $deps = array();
 758
 759                 # Load the primary localisation from the source file
 760                 $data = $this->readSourceFilesAndRegisterDeps( $code, $deps );
 761                 if ( $data === false ) {
 762                         wfDebug( __METHOD__ . ": no localisation file for $code, using fallback to en\n" );
 763                         $coreData['fallback'] = 'en';
 764                 } else {
 765                         wfDebug( __METHOD__ . ": got localisation for $code from source\n" );
 766
 767                         # Merge primary localisation
 768                         foreach ( $data as $key => $value ) {
 769                                 $this->mergeItem( $key, $coreData[$key], $value );
 770                         }
 771                 }
 772
 773                 # Fill in the fallback if it's not there already
 774                 if ( is_null( $coreData['fallback'] ) ) {
 775                         $coreData['fallback'] = $code === 'en' ? false : 'en';
 776                 }
 777                 if ( $coreData['fallback'] === false ) {
 778                         $coreData['fallbackSequence'] = array();
 779                 } else {
 780                         $coreData['fallbackSequence'] = array_map( 'trim', explode( ',', $coreData['fallback'] ) );
 781                         $len = count( $coreData['fallbackSequence'] );
 782
 783                         # Ensure that the sequence ends at en
 784                         if ( $coreData['fallbackSequence'][$len - 1] !== 'en' ) {
 785                                 $coreData['fallbackSequence'][] = 'en';
 786                         }
 787
 788                         # Load the fallback localisation item by item and merge it
 789                         foreach ( $coreData['fallbackSequence'] as $fbCode ) {
 790                                 # Load the secondary localisation from the source file to
 791                                 # avoid infinite cycles on cyclic fallbacks
 792                                 $fbData = $this->readSourceFilesAndRegisterDeps( $fbCode, $deps );
 793                                 if ( $fbData === false ) {
 794                                         continue;
 795                                 }
 796
 797                                 foreach ( self::$allKeys as $key ) {
 798                                         if ( !isset( $fbData[$key] ) ) {
 799                                                 continue;
 800                                         }
 801
 802                                         if ( is_null( $coreData[$key] ) || $this->isMergeableKey( $key ) ) {
 803                                                 $this->mergeItem( $key, $coreData[$key], $fbData[$key] );
 804                                         }
 805                                 }
 806                         }
 807                 }
 808
 809                 $codeSequence = array_merge( array( $code ), $coreData['fallbackSequence'] );
 810
 811                 # Load the extension localisations
 812                 # This is done after the core because we know the fallback sequence now.
 813                 # But it has a higher precedence for merging so that we can support things
 814                 # like site-specific message overrides.
 815                 wfProfileIn( __METHOD__ . '-extensions' );
 816                 $allData = $initialData;
 817                 foreach ( $wgExtensionMessagesFiles as $fileName ) {
 818                         $data = $this->readPHPFile( $fileName, 'extension' );
 819                         $used = false;
 820
 821                         foreach ( $data as $key => $item ) {
 822                                 if ( $this->mergeExtensionItem( $codeSequence, $key, $allData[$key], $item ) ) {
 823                                         $used = true;
 824                                 }
 825                         }
 826
 827                         if ( $used ) {
 828                                 $deps[] = new FileDependency( $fileName );
 829                         }
 830                 }
 831
 832                 # Merge core data into extension data
 833                 foreach ( $coreData as $key => $item ) {
 834                         $this->mergeItem( $key, $allData[$key], $item );
 835                 }
 836                 wfProfileOut( __METHOD__ . '-extensions' );
 837
 838                 # Add cache dependencies for any referenced globals
 839                 $deps['wgExtensionMessagesFiles'] = new GlobalDependency( 'wgExtensionMessagesFiles' );
 840                 $deps['version'] = new ConstantDependency( 'MW_LC_VERSION' );
 841
 842                 # Add dependencies to the cache entry
 843                 $allData['deps'] = $deps;
 844
 845                 # Replace spaces with underscores in namespace names
 846                 $allData['namespaceNames'] = str_replace( ' ', '_', $allData['namespaceNames'] );
 847
 848                 # And do the same for special page aliases. $page is an array.
 849                 foreach ( $allData['specialPageAliases'] as &$page ) {
 850                         $page = str_replace( ' ', '_', $page );
 851                 }
 852                 # Decouple the reference to prevent accidental damage
 853                 unset( $page );
 854
 855                 # If there were no plural rules, return an empty array
 856                 if ( $allData['pluralRules'] === null ) {
 857                         $allData['pluralRules'] = array();
 858                 }
 859                 if ( $allData['compiledPluralRules'] === null ) {
 860                         $allData['compiledPluralRules'] = array();
 861                 }
 862                 # If there were no plural rule types, return an empty array
 863                 if ( $allData['pluralRuleTypes'] === null ) {
 864                         $allData['pluralRuleTypes'] = array();
 865                 }
 866
 867                 # Set the list keys
 868                 $allData['list'] = array();
 869                 foreach ( self::$splitKeys as $key ) {
 870                         $allData['list'][$key] = array_keys( $allData[$key] );
 871                 }
 872                 # Run hooks
 873                 wfRunHooks( 'LocalisationCacheRecache', array( $this, $code, &$allData ) );
 874
 875                 if ( is_null( $allData['namespaceNames'] ) ) {
 876                         wfProfileOut( __METHOD__ );
 877                         throw new MWException( __METHOD__ . ': Localisation data failed sanity check! ' .
 878                                 'Check that your languages/messages/MessagesEn.php file is intact.' );
 879                 }
 880
 881                 # Set the preload key
 882                 $allData['preload'] = $this->buildPreload( $allData );
 883
 884                 # Save to the process cache and register the items loaded
 885                 $this->data[$code] = $allData;
 886                 foreach ( $allData as $key => $item ) {
 887                         $this->loadedItems[$code][$key] = true;
 888                 }
 889
 890                 # Save to the persistent cache
 891                 wfProfileIn( __METHOD__ . '-write' );
 892                 $this->store->startWrite( $code );
 893                 foreach ( $allData as $key => $value ) {
 894                         if ( in_array( $key, self::$splitKeys ) ) {
 895                                 foreach ( $value as $subkey => $subvalue ) {
 896                                         $this->store->set( "$key:$subkey", $subvalue );
 897                                 }
 898                         } else {
 899                                 $this->store->set( $key, $value );
 900                         }
 901                 }
 902                 $this->store->finishWrite();
 903                 wfProfileOut( __METHOD__ . '-write' );
 904
 905                 # Clear out the MessageBlobStore
 906                 # HACK: If using a null (i.e. disabled) storage backend, we
 907                 # can't write to the MessageBlobStore either
 908                 if ( !$this->store instanceof LCStoreNull ) {
 909                         MessageBlobStore::clear();
 910                 }
 911
 912                 wfProfileOut( __METHOD__ );
 913         }
 914
 915         /**
 916          * Build the preload item from the given pre-cache data.
 917          *
 918          * The preload item will be loaded automatically, improving performance
 919          * for the commonly-requested items it contains.
 920          * @param $data
 921          * @return array
 922          */
 923         protected function buildPreload( $data ) {
 924                 $preload = array( 'messages' => array() );
 925                 foreach ( self::$preloadedKeys as $key ) {
 926                         $preload[$key] = $data[$key];
 927                 }
 928
 929                 foreach ( $data['preloadedMessages'] as $subkey ) {
 930                         if ( isset( $data['messages'][$subkey] ) ) {
 931                                 $subitem = $data['messages'][$subkey];
 932                         } else {
 933                                 $subitem = null;
 934                         }
 935                         $preload['messages'][$subkey] = $subitem;
 936                 }
 937
 938                 return $preload;
 939         }
 940
 941         /**
 942          * Unload the data for a given language from the object cache.
 943          * Reduces memory usage.
 944          * @param $code
 945          */
 946         public function unload( $code ) {
 947                 unset( $this->data[$code] );
 948                 unset( $this->loadedItems[$code] );
 949                 unset( $this->loadedSubitems[$code] );
 950                 unset( $this->initialisedLangs[$code] );
 951                 unset( $this->shallowFallbacks[$code] );
 952
 953                 foreach ( $this->shallowFallbacks as $shallowCode => $fbCode ) {
 954                         if ( $fbCode === $code ) {
 955                                 $this->unload( $shallowCode );
 956                         }
 957                 }
 958         }
 959
 960         /**
 961          * Unload all data
 962          */
 963         public function unloadAll() {
 964                 foreach ( $this->initialisedLangs as $lang => $unused ) {
 965                         $this->unload( $lang );
 966                 }
 967         }
 968
 969         /**
 970          * Disable the storage backend
 971          */
 972         public function disableBackend() {
 973                 $this->store = new LCStoreNull;
 974                 $this->manualRecache = false;
 975         }
 976 }
 977
 978 /**
 979  * Interface for the persistence layer of LocalisationCache.
 980  *
 981  * The persistence layer is two-level hierarchical cache. The first level
 982  * is the language, the second level is the item or subitem.
 983  *
 984  * Since the data for a whole language is rebuilt in one operation, it needs
 985  * to have a fast and atomic method for deleting or replacing all of the
 986  * current data for a given language. The interface reflects this bulk update
 987  * operation. Callers writing to the cache must first call startWrite(), then
 988  * will call set() a couple of thousand times, then will call finishWrite()
 989  * to commit the operation. When finishWrite() is called, the cache is
 990  * expected to delete all data previously stored for that language.
 991  *
 992  * The values stored are PHP variables suitable for serialize(). Implementations
 993  * of LCStore are responsible for serializing and unserializing.
 994  */
 995 interface LCStore {
 996         /**
 997          * Get a value.
 998          * @param string $code Language code
 999          * @param string $key Cache key
1000          */
1001         function get( $code, $key );
1002
1003         /**
1004          * Start a write transaction.
1005          * @param string $code Language code
1006          */
1007         function startWrite( $code );
1008
1009         /**
1010          * Finish a write transaction.
1011          */
1012         function finishWrite();
1013
1014         /**
1015          * Set a key to a given value. startWrite() must be called before this
1016          * is called, and finishWrite() must be called afterwards.
1017          * @param string $key
1018          * @param mixed $value
1019          */
1020         function set( $key, $value );
1021 }
1022
1023 /**
1024  * LCStore implementation which uses PHP accelerator to store data.
1025  * This will work if one of XCache, WinCache or APC cacher is configured.
1026  * (See ObjectCache.php)
1027  */
1028 class LCStoreAccel implements LCStore {
1029         private $currentLang;
1030         private $keys;
1031
1032         public function __construct() {
1033                 $this->cache = wfGetCache( CACHE_ACCEL );
1034         }
1035
1036         public function get( $code, $key ) {
1037                 $k = wfMemcKey( 'l10n', $code, 'k', $key );
1038                 $r = $this->cache->get( $k );
1039
1040                 return $r === false ? null : $r;
1041         }
1042
1043         public function startWrite( $code ) {
1044                 $k = wfMemcKey( 'l10n', $code, 'l' );
1045                 $keys = $this->cache->get( $k );
1046                 if ( $keys ) {
1047                         foreach ( $keys as $k ) {
1048                                 $this->cache->delete( $k );
1049                         }
1050                 }
1051                 $this->currentLang = $code;
1052                 $this->keys = array();
1053         }
1054
1055         public function finishWrite() {
1056                 if ( $this->currentLang ) {
1057                         $k = wfMemcKey( 'l10n', $this->currentLang, 'l' );
1058                         $this->cache->set( $k, array_keys( $this->keys ) );
1059                 }
1060                 $this->currentLang = null;
1061                 $this->keys = array();
1062         }
1063
1064         public function set( $key, $value ) {
1065                 if ( $this->currentLang ) {
1066                         $k = wfMemcKey( 'l10n', $this->currentLang, 'k', $key );
1067                         $this->keys[$k] = true;
1068                         $this->cache->set( $k, $value );
1069                 }
1070         }
1071 }
1072
1073 /**
1074  * LCStore implementation which uses the standard DB functions to store data.
1075  * This will work on any MediaWiki installation.
1076  */
1077 class LCStoreDB implements LCStore {
1078         private $currentLang;
1079         private $writesDone = false;
1080
1081         /**
1082          * @var DatabaseBase
1083          */
1084         private $dbw;
1085         private $batch;
1086         private $readOnly = false;
1087
1088         public function get( $code, $key ) {
1089                 if ( $this->writesDone ) {
1090                         $db = wfGetDB( DB_MASTER );
1091                 } else {
1092                         $db = wfGetDB( DB_SLAVE );
1093                 }
1094                 $row = $db->selectRow( 'l10n_cache', array( 'lc_value' ),
1095                         array( 'lc_lang' => $code, 'lc_key' => $key ), __METHOD__ );
1096                 if ( $row ) {
1097                         return unserialize( $row->lc_value );
1098                 } else {
1099                         return null;
1100                 }
1101         }
1102
1103         public function startWrite( $code ) {
1104                 if ( $this->readOnly ) {
1105                         return;
1106                 }
1107
1108                 if ( !$code ) {
1109                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
1110                 }
1111
1112                 $this->dbw = wfGetDB( DB_MASTER );
1113                 try {
1114                         $this->dbw->begin( __METHOD__ );
1115                         $this->dbw->delete( 'l10n_cache', array( 'lc_lang' => $code ), __METHOD__ );
1116                 } catch ( DBQueryError $e ) {
1117                         if ( $this->dbw->wasReadOnlyError() ) {
1118                                 $this->readOnly = true;
1119                                 $this->dbw->rollback( __METHOD__ );
1120
1121                                 return;
1122                         } else {
1123                                 throw $e;
1124                         }
1125                 }
1126
1127                 $this->currentLang = $code;
1128                 $this->batch = array();
1129         }
1130
1131         public function finishWrite() {
1132                 if ( $this->readOnly ) {
1133                         return;
1134                 }
1135
1136                 if ( $this->batch ) {
1137                         $this->dbw->insert( 'l10n_cache', $this->batch, __METHOD__ );
1138                 }
1139
1140                 $this->dbw->commit( __METHOD__ );
1141                 $this->currentLang = null;
1142                 $this->dbw = null;
1143                 $this->batch = array();
1144                 $this->writesDone = true;
1145         }
1146
1147         public function set( $key, $value ) {
1148                 if ( $this->readOnly ) {
1149                         return;
1150                 }
1151
1152                 if ( is_null( $this->currentLang ) ) {
1153                         throw new MWException( __CLASS__ . ': must call startWrite() before calling set()' );
1154                 }
1155
1156                 $this->batch[] = array(
1157                         'lc_lang' => $this->currentLang,
1158                         'lc_key' => $key,
1159                         'lc_value' => serialize( $value ) );
1160
1161                 if ( count( $this->batch ) >= 100 ) {
1162                         $this->dbw->insert( 'l10n_cache', $this->batch, __METHOD__ );
1163                         $this->batch = array();
1164                 }
1165         }
1166 }
1167
1168 /**
1169  * LCStore implementation which stores data as a collection of CDB files in the
1170  * directory given by $wgCacheDirectory. If $wgCacheDirectory is not set, this
1171  * will throw an exception.
1172  *
1173  * Profiling indicates that on Linux, this implementation outperforms MySQL if
1174  * the directory is on a local filesystem and there is ample kernel cache
1175  * space. The performance advantage is greater when the DBA extension is
1176  * available than it is with the PHP port.
1177  *
1178  * See Cdb.php and http://cr.yp.to/cdb.html
1179  */
1180 class LCStoreCDB implements LCStore {
1181         private $readers;
1182         private $writer;
1183         private $currentLang;
1184         private $directory;
1185
1186         function __construct( $conf = array() ) {
1187                 global $wgCacheDirectory;
1188
1189                 if ( isset( $conf['directory'] ) ) {
1190                         $this->directory = $conf['directory'];
1191                 } else {
1192                         $this->directory = $wgCacheDirectory;
1193                 }
1194         }
1195
1196         public function get( $code, $key ) {
1197                 if ( !isset( $this->readers[$code] ) ) {
1198                         $fileName = $this->getFileName( $code );
1199
1200                         $this->readers[$code] = false;
1201                         if ( file_exists( $fileName ) ) {
1202                                 try {
1203                                         $this->readers[$code] = CdbReader::open( $fileName );
1204                                 } catch ( CdbException $e ) {
1205                                         wfDebug( __METHOD__ . ": unable to open cdb file for reading" );
1206                                 }
1207                         }
1208                 }
1209
1210                 if ( !$this->readers[$code] ) {
1211                         return null;
1212                 } else {
1213                         $value = false;
1214                         try {
1215                                 $value = $this->readers[$code]->get( $key );
1216                         } catch ( CdbException $e ) {
1217                                 wfDebug( __METHOD__ . ": CdbException caught, error message was "
1218                                         . $e->getMessage() );
1219                         }
1220                         if ( $value === false ) {
1221                                 return null;
1222                         }
1223
1224                         return unserialize( $value );
1225                 }
1226         }
1227
1228         public function startWrite( $code ) {
1229                 if ( !file_exists( $this->directory ) ) {
1230                         if ( !wfMkdirParents( $this->directory, null, __METHOD__ ) ) {
1231                                 throw new MWException( "Unable to create the localisation store " .
1232                                         "directory \"{$this->directory}\"" );
1233                         }
1234                 }
1235
1236                 // Close reader to stop permission errors on write
1237                 if ( !empty( $this->readers[$code] ) ) {
1238                         $this->readers[$code]->close();
1239                 }
1240
1241                 try {
1242                         $this->writer = CdbWriter::open( $this->getFileName( $code ) );
1243                 } catch ( CdbException $e ) {
1244                         throw new MWException( $e->getMessage() );
1245                 }
1246                 $this->currentLang = $code;
1247         }
1248
1249         public function finishWrite() {
1250                 // Close the writer
1251                 try {
1252                         $this->writer->close();
1253                 } catch ( CdbException $e ) {
1254                         throw new MWException( $e->getMessage() );
1255                 }
1256                 $this->writer = null;
1257                 unset( $this->readers[$this->currentLang] );
1258                 $this->currentLang = null;
1259         }
1260
1261         public function set( $key, $value ) {
1262                 if ( is_null( $this->writer ) ) {
1263                         throw new MWException( __CLASS__ . ': must call startWrite() before calling set()' );
1264                 }
1265                 try {
1266                         $this->writer->set( $key, serialize( $value ) );
1267                 } catch ( CdbException $e ) {
1268                         throw new MWException( $e->getMessage() );
1269                 }
1270         }
1271
1272         protected function getFileName( $code ) {
1273                 if ( strval( $code ) === '' || strpos( $code, '/' ) !== false ) {
1274                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
1275                 }
1276
1277                 return "{$this->directory}/l10n_cache-$code.cdb";
1278         }
1279 }
1280
1281 /**
1282  * Null store backend, used to avoid DB errors during install
1283  */
1284 class LCStoreNull implements LCStore {
1285         public function get( $code, $key ) {
1286                 return null;
1287         }
1288
1289         public function startWrite( $code ) {
1290         }
1291
1292         public function finishWrite() {
1293         }
1294
1295         public function set( $key, $value ) {
1296         }
1297 }
1298
1299 /**
1300  * A localisation cache optimised for loading large amounts of data for many
1301  * languages. Used by rebuildLocalisationCache.php.
1302  */
1303 class LocalisationCacheBulkLoad extends LocalisationCache {
1304         /**
1305          * A cache of the contents of data files.
1306          * Core files are serialized to avoid using ~1GB of RAM during a recache.
1307          */
1308         private $fileCache = array();
1309
1310         /**
1311          * Most recently used languages. Uses the linked-list aspect of PHP hashtables
1312          * to keep the most recently used language codes at the end of the array, and
1313          * the language codes that are ready to be deleted at the beginning.
1314          */
1315         private $mruLangs = array();
1316
1317         /**
1318          * Maximum number of languages that may be loaded into $this->data
1319          */
1320         private $maxLoadedLangs = 10;
1321
1322         /**
1323          * @param $fileName
1324          * @param $fileType
1325          * @return array|mixed
1326          */
1327         protected function readPHPFile( $fileName, $fileType ) {
1328                 $serialize = $fileType === 'core';
1329                 if ( !isset( $this->fileCache[$fileName][$fileType] ) ) {
1330                         $data = parent::readPHPFile( $fileName, $fileType );
1331
1332                         if ( $serialize ) {
1333                                 $encData = serialize( $data );
1334                         } else {
1335                                 $encData = $data;
1336                         }
1337
1338                         $this->fileCache[$fileName][$fileType] = $encData;
1339
1340                         return $data;
1341                 } elseif ( $serialize ) {
1342                         return unserialize( $this->fileCache[$fileName][$fileType] );
1343                 } else {
1344                         return $this->fileCache[$fileName][$fileType];
1345                 }
1346         }
1347
1348         /**
1349          * @param $code
1350          * @param $key
1351          * @return mixed
1352          */
1353         public function getItem( $code, $key ) {
1354                 unset( $this->mruLangs[$code] );
1355                 $this->mruLangs[$code] = true;
1356
1357                 return parent::getItem( $code, $key );
1358         }
1359
1360         /**
1361          * @param $code
1362          * @param $key
1363          * @param $subkey
1364          * @return
1365          */
1366         public function getSubitem( $code, $key, $subkey ) {
1367                 unset( $this->mruLangs[$code] );
1368                 $this->mruLangs[$code] = true;
1369
1370                 return parent::getSubitem( $code, $key, $subkey );
1371         }
1372
1373         /**
1374          * @param $code
1375          */
1376         public function recache( $code ) {
1377                 parent::recache( $code );
1378                 unset( $this->mruLangs[$code] );
1379                 $this->mruLangs[$code] = true;
1380                 $this->trimCache();
1381         }
1382
1383         /**
1384          * @param $code
1385          */
1386         public function unload( $code ) {
1387                 unset( $this->mruLangs[$code] );
1388                 parent::unload( $code );
1389         }
1390
1391         /**
1392          * Unload cached languages until there are less than $this->maxLoadedLangs
1393          */
1394         protected function trimCache() {
1395                 while ( count( $this->data ) > $this->maxLoadedLangs && count( $this->mruLangs ) ) {
1396                         reset( $this->mruLangs );
1397                         $code = key( $this->mruLangs );
1398                         wfDebug( __METHOD__ . ": unloading $code\n" );
1399                         $this->unload( $code );
1400                 }
1401         }
1402 }