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