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          * Read a JSON file containing localisation messages.
 532          * @param string $fileName Name of file to read
 533          * @throws MWException if there is a syntax error in the JSON file
 534          * @return array with a 'messages' key, or empty array if the file doesn't exist
 535          */
 536         protected function readJSONFile( $fileName ) {
 537                 wfProfileIn( __METHOD__ );
 538                 if ( !is_readable( $fileName ) ) {
 539                         return array();
 540                 }
 541
 542                 $json = file_get_contents( $fileName );
 543                 if ( $json === false ) {
 544                         return array();
 545                 }
 546                 $data = FormatJson::decode( $json, true );
 547                 if ( $data === null ) {
 548                         throw new MWException( __METHOD__ . ": Invalid JSON file: $fileName" );
 549                 }
 550                 // Remove keys starting with '@', they're reserved for metadata and non-message data
 551                 foreach ( $data as $key => $unused ) {
 552                         if ( $key === '' || $key[0] === '@' ) {
 553                                 unset( $data[$key] );
 554                         }
 555                 }
 556                 // The JSON format only supports messages, none of the other variables, so wrap the data
 557                 return array( 'messages' => $data );
 558         }
 559
 560         /**
 561          * Get the compiled plural rules for a given language from the XML files.
 562          * @since 1.20
 563          */
 564         public function getCompiledPluralRules( $code ) {
 565                 $rules = $this->getPluralRules( $code );
 566                 if ( $rules === null ) {
 567                         return null;
 568                 }
 569                 try {
 570                         $compiledRules = CLDRPluralRuleEvaluator::compile( $rules );
 571                 } catch ( CLDRPluralRuleError $e ) {
 572                         wfDebugLog( 'l10n', $e->getMessage() . "\n" );
 573
 574                         return array();
 575                 }
 576
 577                 return $compiledRules;
 578         }
 579
 580         /**
 581          * Get the plural rules for a given language from the XML files.
 582          * Cached.
 583          * @since 1.20
 584          */
 585         public function getPluralRules( $code ) {
 586                 if ( $this->pluralRules === null ) {
 587                         $this->loadPluralFiles();
 588                 }
 589                 if ( !isset( $this->pluralRules[$code] ) ) {
 590                         return null;
 591                 } else {
 592                         return $this->pluralRules[$code];
 593                 }
 594         }
 595
 596         /**
 597          * Get the plural rule types for a given language from the XML files.
 598          * Cached.
 599          * @since 1.22
 600          */
 601         public function getPluralRuleTypes( $code ) {
 602                 if ( $this->pluralRuleTypes === null ) {
 603                         $this->loadPluralFiles();
 604                 }
 605                 if ( !isset( $this->pluralRuleTypes[$code] ) ) {
 606                         return null;
 607                 } else {
 608                         return $this->pluralRuleTypes[$code];
 609                 }
 610         }
 611
 612         /**
 613          * Load the plural XML files.
 614          */
 615         protected function loadPluralFiles() {
 616                 global $IP;
 617                 $cldrPlural = "$IP/languages/data/plurals.xml";
 618                 $mwPlural = "$IP/languages/data/plurals-mediawiki.xml";
 619                 // Load CLDR plural rules
 620                 $this->loadPluralFile( $cldrPlural );
 621                 if ( file_exists( $mwPlural ) ) {
 622                         // Override or extend
 623                         $this->loadPluralFile( $mwPlural );
 624                 }
 625         }
 626
 627         /**
 628          * Load a plural XML file with the given filename, compile the relevant
 629          * rules, and save the compiled rules in a process-local cache.
 630          */
 631         protected function loadPluralFile( $fileName ) {
 632                 $doc = new DOMDocument;
 633                 $doc->load( $fileName );
 634                 $rulesets = $doc->getElementsByTagName( "pluralRules" );
 635                 foreach ( $rulesets as $ruleset ) {
 636                         $codes = $ruleset->getAttribute( 'locales' );
 637                         $rules = array();
 638                         $ruleTypes = array();
 639                         $ruleElements = $ruleset->getElementsByTagName( "pluralRule" );
 640                         foreach ( $ruleElements as $elt ) {
 641                                 $ruleType = $elt->getAttribute( 'count' );
 642                                 if ( $ruleType === 'other' ) {
 643                                         // Don't record "other" rules, which have an empty condition
 644                                         continue;
 645                                 }
 646                                 $rules[] = $elt->nodeValue;
 647                                 $ruleTypes[] = $ruleType;
 648                         }
 649                         foreach ( explode( ' ', $codes ) as $code ) {
 650                                 $this->pluralRules[$code] = $rules;
 651                                 $this->pluralRuleTypes[$code] = $ruleTypes;
 652                         }
 653                 }
 654         }
 655
 656         /**
 657          * Read the data from the source files for a given language, and register
 658          * the relevant dependencies in the $deps array. If the localisation
 659          * exists, the data array is returned, otherwise false is returned.
 660          */
 661         protected function readSourceFilesAndRegisterDeps( $code, &$deps ) {
 662                 global $IP;
 663                 wfProfileIn( __METHOD__ );
 664
 665                 $fileName = Language::getMessagesFileName( $code );
 666                 if ( !file_exists( $fileName ) ) {
 667                         wfProfileOut( __METHOD__ );
 668
 669                         return false;
 670                 }
 671
 672                 $deps[] = new FileDependency( $fileName );
 673                 $data = $this->readPHPFile( $fileName, 'core' );
 674
 675                 # Load CLDR plural rules for JavaScript
 676                 $data['pluralRules'] = $this->getPluralRules( $code );
 677                 # And for PHP
 678                 $data['compiledPluralRules'] = $this->getCompiledPluralRules( $code );
 679                 # Load plural rule types
 680                 $data['pluralRuleTypes'] = $this->getPluralRuleTypes( $code );
 681
 682                 $deps['plurals'] = new FileDependency( "$IP/languages/data/plurals.xml" );
 683                 $deps['plurals-mw'] = new FileDependency( "$IP/languages/data/plurals-mediawiki.xml" );
 684
 685                 wfProfileOut( __METHOD__ );
 686
 687                 return $data;
 688         }
 689
 690         /**
 691          * Merge two localisation values, a primary and a fallback, overwriting the
 692          * primary value in place.
 693          * @param $key
 694          * @param $value
 695          * @param $fallbackValue
 696          */
 697         protected function mergeItem( $key, &$value, $fallbackValue ) {
 698                 if ( !is_null( $value ) ) {
 699                         if ( !is_null( $fallbackValue ) ) {
 700                                 if ( in_array( $key, self::$mergeableMapKeys ) ) {
 701                                         $value = $value + $fallbackValue;
 702                                 } elseif ( in_array( $key, self::$mergeableListKeys ) ) {
 703                                         $value = array_unique( array_merge( $fallbackValue, $value ) );
 704                                 } elseif ( in_array( $key, self::$mergeableAliasListKeys ) ) {
 705                                         $value = array_merge_recursive( $value, $fallbackValue );
 706                                 } elseif ( in_array( $key, self::$optionalMergeKeys ) ) {
 707                                         if ( !empty( $value['inherit'] ) ) {
 708                                                 $value = array_merge( $fallbackValue, $value );
 709                                         }
 710
 711                                         if ( isset( $value['inherit'] ) ) {
 712                                                 unset( $value['inherit'] );
 713                                         }
 714                                 } elseif ( in_array( $key, self::$magicWordKeys ) ) {
 715                                         $this->mergeMagicWords( $value, $fallbackValue );
 716                                 }
 717                         }
 718                 } else {
 719                         $value = $fallbackValue;
 720                 }
 721         }
 722
 723         /**
 724          * @param $value
 725          * @param $fallbackValue
 726          */
 727         protected function mergeMagicWords( &$value, $fallbackValue ) {
 728                 foreach ( $fallbackValue as $magicName => $fallbackInfo ) {
 729                         if ( !isset( $value[$magicName] ) ) {
 730                                 $value[$magicName] = $fallbackInfo;
 731                         } else {
 732                                 $oldSynonyms = array_slice( $fallbackInfo, 1 );
 733                                 $newSynonyms = array_slice( $value[$magicName], 1 );
 734                                 $synonyms = array_values( array_unique( array_merge(
 735                                         $newSynonyms, $oldSynonyms ) ) );
 736                                 $value[$magicName] = array_merge( array( $fallbackInfo[0] ), $synonyms );
 737                         }
 738                 }
 739         }
 740
 741         /**
 742          * Given an array mapping language code to localisation value, such as is
 743          * found in extension *.i18n.php files, iterate through a fallback sequence
 744          * to merge the given data with an existing primary value.
 745          *
 746          * Returns true if any data from the extension array was used, false
 747          * otherwise.
 748          * @param $codeSequence
 749          * @param $key
 750          * @param $value
 751          * @param $fallbackValue
 752          * @return bool
 753          */
 754         protected function mergeExtensionItem( $codeSequence, $key, &$value, $fallbackValue ) {
 755                 $used = false;
 756                 foreach ( $codeSequence as $code ) {
 757                         if ( isset( $fallbackValue[$code] ) ) {
 758                                 $this->mergeItem( $key, $value, $fallbackValue[$code] );
 759                                 $used = true;
 760                         }
 761                 }
 762
 763                 return $used;
 764         }
 765
 766         /**
 767          * Load localisation data for a given language for both core and extensions
 768          * and save it to the persistent cache store and the process cache
 769          * @param $code
 770          * @throws MWException
 771          */
 772         public function recache( $code ) {
 773                 global $wgExtensionMessagesFiles, $wgMessagesDirs;
 774                 wfProfileIn( __METHOD__ );
 775
 776                 if ( !$code ) {
 777                         wfProfileOut( __METHOD__ );
 778                         throw new MWException( "Invalid language code requested" );
 779                 }
 780                 $this->recachedLangs[$code] = true;
 781
 782                 # Initial values
 783                 $initialData = array_combine(
 784                         self::$allKeys,
 785                         array_fill( 0, count( self::$allKeys ), null ) );
 786                 $coreData = $initialData;
 787                 $deps = array();
 788
 789                 # Load the primary localisation from the source file
 790                 $data = $this->readSourceFilesAndRegisterDeps( $code, $deps );
 791                 if ( $data === false ) {
 792                         wfDebug( __METHOD__ . ": no localisation file for $code, using fallback to en\n" );
 793                         $coreData['fallback'] = 'en';
 794                 } else {
 795                         wfDebug( __METHOD__ . ": got localisation for $code from source\n" );
 796
 797                         # Merge primary localisation
 798                         foreach ( $data as $key => $value ) {
 799                                 $this->mergeItem( $key, $coreData[$key], $value );
 800                         }
 801                 }
 802
 803                 # Fill in the fallback if it's not there already
 804                 if ( is_null( $coreData['fallback'] ) ) {
 805                         $coreData['fallback'] = $code === 'en' ? false : 'en';
 806                 }
 807                 if ( $coreData['fallback'] === false ) {
 808                         $coreData['fallbackSequence'] = array();
 809                 } else {
 810                         $coreData['fallbackSequence'] = array_map( 'trim', explode( ',', $coreData['fallback'] ) );
 811                         $len = count( $coreData['fallbackSequence'] );
 812
 813                         # Ensure that the sequence ends at en
 814                         if ( $coreData['fallbackSequence'][$len - 1] !== 'en' ) {
 815                                 $coreData['fallbackSequence'][] = 'en';
 816                         }
 817
 818                         # Load the fallback localisation item by item and merge it
 819                         foreach ( $coreData['fallbackSequence'] as $fbCode ) {
 820                                 # Load the secondary localisation from the source file to
 821                                 # avoid infinite cycles on cyclic fallbacks
 822                                 $fbData = $this->readSourceFilesAndRegisterDeps( $fbCode, $deps );
 823                                 if ( $fbData === false ) {
 824                                         continue;
 825                                 }
 826
 827                                 foreach ( self::$allKeys as $key ) {
 828                                         if ( !isset( $fbData[$key] ) ) {
 829                                                 continue;
 830                                         }
 831
 832                                         if ( is_null( $coreData[$key] ) || $this->isMergeableKey( $key ) ) {
 833                                                 $this->mergeItem( $key, $coreData[$key], $fbData[$key] );
 834                                         }
 835                                 }
 836                         }
 837                 }
 838
 839                 $codeSequence = array_merge( array( $code ), $coreData['fallbackSequence'] );
 840
 841                 # Load the extension localisations
 842                 # This is done after the core because we know the fallback sequence now.
 843                 # But it has a higher precedence for merging so that we can support things
 844                 # like site-specific message overrides.
 845                 wfProfileIn( __METHOD__ . '-extensions' );
 846                 $allData = $initialData;
 847                 foreach ( $wgMessagesDirs as $dirs ) {
 848                         foreach ( (array)$dirs as $dir ) {
 849                                 foreach ( $codeSequence as $csCode ) {
 850                                         $fileName = "$dir/$csCode.json";
 851                                         $data = $this->readJSONFile( $fileName );
 852
 853                                         foreach ( $data as $key => $item ) {
 854                                                 $this->mergeItem( $key, $allData[$key], $item );
 855                                         }
 856
 857                                         $deps[] = new FileDependency( $fileName );
 858                                 }
 859                         }
 860                 }
 861
 862                 foreach ( $wgExtensionMessagesFiles as $extension => $fileName ) {
 863                         $data = $this->readPHPFile( $fileName, 'extension' );
 864                         $used = false;
 865
 866                         foreach ( $data as $key => $item ) {
 867                                 if ( $key === 'messages' && isset( $wgMessagesDirs[$extension] ) ) {
 868                                         # For backwards compatibility, ignore messages from extensions in
 869                                         # $wgExtensionMessagesFiles that are also present in $wgMessagesDirs.
 870                                         # This allows extensions to use both and be backwards compatible.
 871                                         # Variables other than $messages still need to be supported though.
 872                                         continue;
 873                                 }
 874                                 if ( $this->mergeExtensionItem( $codeSequence, $key, $allData[$key], $item ) ) {
 875                                         $used = true;
 876                                 }
 877                         }
 878
 879                         if ( $used ) {
 880                                 $deps[] = new FileDependency( $fileName );
 881                         }
 882                 }
 883
 884                 # Merge core data into extension data
 885                 foreach ( $coreData as $key => $item ) {
 886                         $this->mergeItem( $key, $allData[$key], $item );
 887                 }
 888                 wfProfileOut( __METHOD__ . '-extensions' );
 889
 890                 # Add cache dependencies for any referenced globals
 891                 $deps['wgExtensionMessagesFiles'] = new GlobalDependency( 'wgExtensionMessagesFiles' );
 892                 $deps['wgMessagesDirs'] = new GlobalDependency( 'wgMessagesDirs' );
 893                 $deps['version'] = new ConstantDependency( 'MW_LC_VERSION' );
 894
 895                 # Add dependencies to the cache entry
 896                 $allData['deps'] = $deps;
 897
 898                 # Replace spaces with underscores in namespace names
 899                 $allData['namespaceNames'] = str_replace( ' ', '_', $allData['namespaceNames'] );
 900
 901                 # And do the same for special page aliases. $page is an array.
 902                 foreach ( $allData['specialPageAliases'] as &$page ) {
 903                         $page = str_replace( ' ', '_', $page );
 904                 }
 905                 # Decouple the reference to prevent accidental damage
 906                 unset( $page );
 907
 908                 # If there were no plural rules, return an empty array
 909                 if ( $allData['pluralRules'] === null ) {
 910                         $allData['pluralRules'] = array();
 911                 }
 912                 if ( $allData['compiledPluralRules'] === null ) {
 913                         $allData['compiledPluralRules'] = array();
 914                 }
 915                 # If there were no plural rule types, return an empty array
 916                 if ( $allData['pluralRuleTypes'] === null ) {
 917                         $allData['pluralRuleTypes'] = array();
 918                 }
 919
 920                 # Set the list keys
 921                 $allData['list'] = array();
 922                 foreach ( self::$splitKeys as $key ) {
 923                         $allData['list'][$key] = array_keys( $allData[$key] );
 924                 }
 925                 # Run hooks
 926                 wfRunHooks( 'LocalisationCacheRecache', array( $this, $code, &$allData ) );
 927
 928                 if ( is_null( $allData['namespaceNames'] ) ) {
 929                         wfProfileOut( __METHOD__ );
 930                         throw new MWException( __METHOD__ . ': Localisation data failed sanity check! ' .
 931                                 'Check that your languages/messages/MessagesEn.php file is intact.' );
 932                 }
 933
 934                 # Set the preload key
 935                 $allData['preload'] = $this->buildPreload( $allData );
 936
 937                 # Save to the process cache and register the items loaded
 938                 $this->data[$code] = $allData;
 939                 foreach ( $allData as $key => $item ) {
 940                         $this->loadedItems[$code][$key] = true;
 941                 }
 942
 943                 # Save to the persistent cache
 944                 wfProfileIn( __METHOD__ . '-write' );
 945                 $this->store->startWrite( $code );
 946                 foreach ( $allData as $key => $value ) {
 947                         if ( in_array( $key, self::$splitKeys ) ) {
 948                                 foreach ( $value as $subkey => $subvalue ) {
 949                                         $this->store->set( "$key:$subkey", $subvalue );
 950                                 }
 951                         } else {
 952                                 $this->store->set( $key, $value );
 953                         }
 954                 }
 955                 $this->store->finishWrite();
 956                 wfProfileOut( __METHOD__ . '-write' );
 957
 958                 # Clear out the MessageBlobStore
 959                 # HACK: If using a null (i.e. disabled) storage backend, we
 960                 # can't write to the MessageBlobStore either
 961                 if ( !$this->store instanceof LCStoreNull ) {
 962                         MessageBlobStore::clear();
 963                 }
 964
 965                 wfProfileOut( __METHOD__ );
 966         }
 967
 968         /**
 969          * Build the preload item from the given pre-cache data.
 970          *
 971          * The preload item will be loaded automatically, improving performance
 972          * for the commonly-requested items it contains.
 973          * @param $data
 974          * @return array
 975          */
 976         protected function buildPreload( $data ) {
 977                 $preload = array( 'messages' => array() );
 978                 foreach ( self::$preloadedKeys as $key ) {
 979                         $preload[$key] = $data[$key];
 980                 }
 981
 982                 foreach ( $data['preloadedMessages'] as $subkey ) {
 983                         if ( isset( $data['messages'][$subkey] ) ) {
 984                                 $subitem = $data['messages'][$subkey];
 985                         } else {
 986                                 $subitem = null;
 987                         }
 988                         $preload['messages'][$subkey] = $subitem;
 989                 }
 990
 991                 return $preload;
 992         }
 993
 994         /**
 995          * Unload the data for a given language from the object cache.
 996          * Reduces memory usage.
 997          * @param $code
 998          */
 999         public function unload( $code ) {
1000                 unset( $this->data[$code] );
1001                 unset( $this->loadedItems[$code] );
1002                 unset( $this->loadedSubitems[$code] );
1003                 unset( $this->initialisedLangs[$code] );
1004                 unset( $this->shallowFallbacks[$code] );
1005
1006                 foreach ( $this->shallowFallbacks as $shallowCode => $fbCode ) {
1007                         if ( $fbCode === $code ) {
1008                                 $this->unload( $shallowCode );
1009                         }
1010                 }
1011         }
1012
1013         /**
1014          * Unload all data
1015          */
1016         public function unloadAll() {
1017                 foreach ( $this->initialisedLangs as $lang => $unused ) {
1018                         $this->unload( $lang );
1019                 }
1020         }
1021
1022         /**
1023          * Disable the storage backend
1024          */
1025         public function disableBackend() {
1026                 $this->store = new LCStoreNull;
1027                 $this->manualRecache = false;
1028         }
1029 }
1030
1031 /**
1032  * Interface for the persistence layer of LocalisationCache.
1033  *
1034  * The persistence layer is two-level hierarchical cache. The first level
1035  * is the language, the second level is the item or subitem.
1036  *
1037  * Since the data for a whole language is rebuilt in one operation, it needs
1038  * to have a fast and atomic method for deleting or replacing all of the
1039  * current data for a given language. The interface reflects this bulk update
1040  * operation. Callers writing to the cache must first call startWrite(), then
1041  * will call set() a couple of thousand times, then will call finishWrite()
1042  * to commit the operation. When finishWrite() is called, the cache is
1043  * expected to delete all data previously stored for that language.
1044  *
1045  * The values stored are PHP variables suitable for serialize(). Implementations
1046  * of LCStore are responsible for serializing and unserializing.
1047  */
1048 interface LCStore {
1049         /**
1050          * Get a value.
1051          * @param string $code Language code
1052          * @param string $key Cache key
1053          */
1054         function get( $code, $key );
1055
1056         /**
1057          * Start a write transaction.
1058          * @param string $code Language code
1059          */
1060         function startWrite( $code );
1061
1062         /**
1063          * Finish a write transaction.
1064          */
1065         function finishWrite();
1066
1067         /**
1068          * Set a key to a given value. startWrite() must be called before this
1069          * is called, and finishWrite() must be called afterwards.
1070          * @param string $key
1071          * @param mixed $value
1072          */
1073         function set( $key, $value );
1074 }
1075
1076 /**
1077  * LCStore implementation which uses PHP accelerator to store data.
1078  * This will work if one of XCache, WinCache or APC cacher is configured.
1079  * (See ObjectCache.php)
1080  */
1081 class LCStoreAccel implements LCStore {
1082         private $currentLang;
1083         private $keys;
1084
1085         public function __construct() {
1086                 $this->cache = wfGetCache( CACHE_ACCEL );
1087         }
1088
1089         public function get( $code, $key ) {
1090                 $k = wfMemcKey( 'l10n', $code, 'k', $key );
1091                 $r = $this->cache->get( $k );
1092
1093                 return $r === false ? null : $r;
1094         }
1095
1096         public function startWrite( $code ) {
1097                 $k = wfMemcKey( 'l10n', $code, 'l' );
1098                 $keys = $this->cache->get( $k );
1099                 if ( $keys ) {
1100                         foreach ( $keys as $k ) {
1101                                 $this->cache->delete( $k );
1102                         }
1103                 }
1104                 $this->currentLang = $code;
1105                 $this->keys = array();
1106         }
1107
1108         public function finishWrite() {
1109                 if ( $this->currentLang ) {
1110                         $k = wfMemcKey( 'l10n', $this->currentLang, 'l' );
1111                         $this->cache->set( $k, array_keys( $this->keys ) );
1112                 }
1113                 $this->currentLang = null;
1114                 $this->keys = array();
1115         }
1116
1117         public function set( $key, $value ) {
1118                 if ( $this->currentLang ) {
1119                         $k = wfMemcKey( 'l10n', $this->currentLang, 'k', $key );
1120                         $this->keys[$k] = true;
1121                         $this->cache->set( $k, $value );
1122                 }
1123         }
1124 }
1125
1126 /**
1127  * LCStore implementation which uses the standard DB functions to store data.
1128  * This will work on any MediaWiki installation.
1129  */
1130 class LCStoreDB implements LCStore {
1131         private $currentLang;
1132         private $writesDone = false;
1133
1134         /**
1135          * @var DatabaseBase
1136          */
1137         private $dbw;
1138         private $batch;
1139         private $readOnly = false;
1140
1141         public function get( $code, $key ) {
1142                 if ( $this->writesDone ) {
1143                         $db = wfGetDB( DB_MASTER );
1144                 } else {
1145                         $db = wfGetDB( DB_SLAVE );
1146                 }
1147                 $row = $db->selectRow( 'l10n_cache', array( 'lc_value' ),
1148                         array( 'lc_lang' => $code, 'lc_key' => $key ), __METHOD__ );
1149                 if ( $row ) {
1150                         return unserialize( $row->lc_value );
1151                 } else {
1152                         return null;
1153                 }
1154         }
1155
1156         public function startWrite( $code ) {
1157                 if ( $this->readOnly ) {
1158                         return;
1159                 }
1160
1161                 if ( !$code ) {
1162                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
1163                 }
1164
1165                 $this->dbw = wfGetDB( DB_MASTER );
1166                 try {
1167                         $this->dbw->begin( __METHOD__ );
1168                         $this->dbw->delete( 'l10n_cache', array( 'lc_lang' => $code ), __METHOD__ );
1169                 } catch ( DBQueryError $e ) {
1170                         if ( $this->dbw->wasReadOnlyError() ) {
1171                                 $this->readOnly = true;
1172                                 $this->dbw->rollback( __METHOD__ );
1173
1174                                 return;
1175                         } else {
1176                                 throw $e;
1177                         }
1178                 }
1179
1180                 $this->currentLang = $code;
1181                 $this->batch = array();
1182         }
1183
1184         public function finishWrite() {
1185                 if ( $this->readOnly ) {
1186                         return;
1187                 }
1188
1189                 if ( $this->batch ) {
1190                         $this->dbw->insert( 'l10n_cache', $this->batch, __METHOD__ );
1191                 }
1192
1193                 $this->dbw->commit( __METHOD__ );
1194                 $this->currentLang = null;
1195                 $this->dbw = null;
1196                 $this->batch = array();
1197                 $this->writesDone = true;
1198         }
1199
1200         public function set( $key, $value ) {
1201                 if ( $this->readOnly ) {
1202                         return;
1203                 }
1204
1205                 if ( is_null( $this->currentLang ) ) {
1206                         throw new MWException( __CLASS__ . ': must call startWrite() before calling set()' );
1207                 }
1208
1209                 $this->batch[] = array(
1210                         'lc_lang' => $this->currentLang,
1211                         'lc_key' => $key,
1212                         'lc_value' => serialize( $value ) );
1213
1214                 if ( count( $this->batch ) >= 100 ) {
1215                         $this->dbw->insert( 'l10n_cache', $this->batch, __METHOD__ );
1216                         $this->batch = array();
1217                 }
1218         }
1219 }
1220
1221 /**
1222  * LCStore implementation which stores data as a collection of CDB files in the
1223  * directory given by $wgCacheDirectory. If $wgCacheDirectory is not set, this
1224  * will throw an exception.
1225  *
1226  * Profiling indicates that on Linux, this implementation outperforms MySQL if
1227  * the directory is on a local filesystem and there is ample kernel cache
1228  * space. The performance advantage is greater when the DBA extension is
1229  * available than it is with the PHP port.
1230  *
1231  * See Cdb.php and http://cr.yp.to/cdb.html
1232  */
1233 class LCStoreCDB implements LCStore {
1234         private $readers;
1235         private $writer;
1236         private $currentLang;
1237         private $directory;
1238
1239         function __construct( $conf = array() ) {
1240                 global $wgCacheDirectory;
1241
1242                 if ( isset( $conf['directory'] ) ) {
1243                         $this->directory = $conf['directory'];
1244                 } else {
1245                         $this->directory = $wgCacheDirectory;
1246                 }
1247         }
1248
1249         public function get( $code, $key ) {
1250                 if ( !isset( $this->readers[$code] ) ) {
1251                         $fileName = $this->getFileName( $code );
1252
1253                         $this->readers[$code] = false;
1254                         if ( file_exists( $fileName ) ) {
1255                                 try {
1256                                         $this->readers[$code] = CdbReader::open( $fileName );
1257                                 } catch ( CdbException $e ) {
1258                                         wfDebug( __METHOD__ . ": unable to open cdb file for reading" );
1259                                 }
1260                         }
1261                 }
1262
1263                 if ( !$this->readers[$code] ) {
1264                         return null;
1265                 } else {
1266                         $value = false;
1267                         try {
1268                                 $value = $this->readers[$code]->get( $key );
1269                         } catch ( CdbException $e ) {
1270                                 wfDebug( __METHOD__ . ": CdbException caught, error message was "
1271                                         . $e->getMessage() );
1272                         }
1273                         if ( $value === false ) {
1274                                 return null;
1275                         }
1276
1277                         return unserialize( $value );
1278                 }
1279         }
1280
1281         public function startWrite( $code ) {
1282                 if ( !file_exists( $this->directory ) ) {
1283                         if ( !wfMkdirParents( $this->directory, null, __METHOD__ ) ) {
1284                                 throw new MWException( "Unable to create the localisation store " .
1285                                         "directory \"{$this->directory}\"" );
1286                         }
1287                 }
1288
1289                 // Close reader to stop permission errors on write
1290                 if ( !empty( $this->readers[$code] ) ) {
1291                         $this->readers[$code]->close();
1292                 }
1293
1294                 try {
1295                         $this->writer = CdbWriter::open( $this->getFileName( $code ) );
1296                 } catch ( CdbException $e ) {
1297                         throw new MWException( $e->getMessage() );
1298                 }
1299                 $this->currentLang = $code;
1300         }
1301
1302         public function finishWrite() {
1303                 // Close the writer
1304                 try {
1305                         $this->writer->close();
1306                 } catch ( CdbException $e ) {
1307                         throw new MWException( $e->getMessage() );
1308                 }
1309                 $this->writer = null;
1310                 unset( $this->readers[$this->currentLang] );
1311                 $this->currentLang = null;
1312         }
1313
1314         public function set( $key, $value ) {
1315                 if ( is_null( $this->writer ) ) {
1316                         throw new MWException( __CLASS__ . ': must call startWrite() before calling set()' );
1317                 }
1318                 try {
1319                         $this->writer->set( $key, serialize( $value ) );
1320                 } catch ( CdbException $e ) {
1321                         throw new MWException( $e->getMessage() );
1322                 }
1323         }
1324
1325         protected function getFileName( $code ) {
1326                 if ( strval( $code ) === '' || strpos( $code, '/' ) !== false ) {
1327                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
1328                 }
1329
1330                 return "{$this->directory}/l10n_cache-$code.cdb";
1331         }
1332 }
1333
1334 /**
1335  * Null store backend, used to avoid DB errors during install
1336  */
1337 class LCStoreNull implements LCStore {
1338         public function get( $code, $key ) {
1339                 return null;
1340         }
1341
1342         public function startWrite( $code ) {
1343         }
1344
1345         public function finishWrite() {
1346         }
1347
1348         public function set( $key, $value ) {
1349         }
1350 }
1351
1352 /**
1353  * A localisation cache optimised for loading large amounts of data for many
1354  * languages. Used by rebuildLocalisationCache.php.
1355  */
1356 class LocalisationCacheBulkLoad extends LocalisationCache {
1357         /**
1358          * A cache of the contents of data files.
1359          * Core files are serialized to avoid using ~1GB of RAM during a recache.
1360          */
1361         private $fileCache = array();
1362
1363         /**
1364          * Most recently used languages. Uses the linked-list aspect of PHP hashtables
1365          * to keep the most recently used language codes at the end of the array, and
1366          * the language codes that are ready to be deleted at the beginning.
1367          */
1368         private $mruLangs = array();
1369
1370         /**
1371          * Maximum number of languages that may be loaded into $this->data
1372          */
1373         private $maxLoadedLangs = 10;
1374
1375         /**
1376          * @param $fileName
1377          * @param $fileType
1378          * @return array|mixed
1379          */
1380         protected function readPHPFile( $fileName, $fileType ) {
1381                 $serialize = $fileType === 'core';
1382                 if ( !isset( $this->fileCache[$fileName][$fileType] ) ) {
1383                         $data = parent::readPHPFile( $fileName, $fileType );
1384
1385                         if ( $serialize ) {
1386                                 $encData = serialize( $data );
1387                         } else {
1388                                 $encData = $data;
1389                         }
1390
1391                         $this->fileCache[$fileName][$fileType] = $encData;
1392
1393                         return $data;
1394                 } elseif ( $serialize ) {
1395                         return unserialize( $this->fileCache[$fileName][$fileType] );
1396                 } else {
1397                         return $this->fileCache[$fileName][$fileType];
1398                 }
1399         }
1400
1401         /**
1402          * @param $code
1403          * @param $key
1404          * @return mixed
1405          */
1406         public function getItem( $code, $key ) {
1407                 unset( $this->mruLangs[$code] );
1408                 $this->mruLangs[$code] = true;
1409
1410                 return parent::getItem( $code, $key );
1411         }
1412
1413         /**
1414          * @param $code
1415          * @param $key
1416          * @param $subkey
1417          * @return
1418          */
1419         public function getSubitem( $code, $key, $subkey ) {
1420                 unset( $this->mruLangs[$code] );
1421                 $this->mruLangs[$code] = true;
1422
1423                 return parent::getSubitem( $code, $key, $subkey );
1424         }
1425
1426         /**
1427          * @param $code
1428          */
1429         public function recache( $code ) {
1430                 parent::recache( $code );
1431                 unset( $this->mruLangs[$code] );
1432                 $this->mruLangs[$code] = true;
1433                 $this->trimCache();
1434         }
1435
1436         /**
1437          * @param $code
1438          */
1439         public function unload( $code ) {
1440                 unset( $this->mruLangs[$code] );
1441                 parent::unload( $code );
1442         }
1443
1444         /**
1445          * Unload cached languages until there are less than $this->maxLoadedLangs
1446          */
1447         protected function trimCache() {
1448                 while ( count( $this->data ) > $this->maxLoadedLangs && count( $this->mruLangs ) ) {
1449                         reset( $this->mruLangs );
1450                         $code = key( $this->mruLangs );
1451                         wfDebug( __METHOD__ . ": unloading $code\n" );
1452                         $this->unload( $code );
1453                 }
1454         }
1455 }