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 /**
  24  * Class for caching the contents of localisation files, Messages*.php
  25  * and *.i18n.php.
  26  *
  27  * An instance of this class is available using Language::getLocalisationCache().
  28  *
  29  * The values retrieved from here are merged, containing items from extension
  30  * files, core messages files and the language fallback sequence (e.g. zh-cn ->
  31  * zh-hans -> en ). Some common errors are corrected, for example namespace
  32  * names with spaces instead of underscores, but heavyweight processing, such
  33  * as grammatical transformation, is done by the caller.
  34  */
  35 class LocalisationCache {
  36         const VERSION = 2;
  37
  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 array $conf
 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 'detect':
 204                                         $storeClass = $wgCacheDirectory ? 'LCStoreCDB' : 'LCStoreDB';
 205                                         break;
 206                                 default:
 207                                         throw new MWException(
 208                                                 'Please set $wgLocalisationCacheConf[\'store\'] to something sensible.' );
 209                         }
 210                 }
 211
 212                 wfDebugLog( 'caches', get_class( $this ) . ": using store $storeClass" );
 213                 if ( !empty( $conf['storeDirectory'] ) ) {
 214                         $storeConf['directory'] = $conf['storeDirectory'];
 215                 }
 216
 217                 $this->store = new $storeClass( $storeConf );
 218                 foreach ( array( 'manualRecache', 'forceRecache' ) as $var ) {
 219                         if ( isset( $conf[$var] ) ) {
 220                                 $this->$var = $conf[$var];
 221                         }
 222                 }
 223         }
 224
 225         /**
 226          * Returns true if the given key is mergeable, that is, if it is an associative
 227          * array which can be merged through a fallback sequence.
 228          * @param string $key
 229          * @return bool
 230          */
 231         public function isMergeableKey( $key ) {
 232                 if ( $this->mergeableKeys === null ) {
 233                         $this->mergeableKeys = array_flip( array_merge(
 234                                 self::$mergeableMapKeys,
 235                                 self::$mergeableListKeys,
 236                                 self::$mergeableAliasListKeys,
 237                                 self::$optionalMergeKeys,
 238                                 self::$magicWordKeys
 239                         ) );
 240                 }
 241
 242                 return isset( $this->mergeableKeys[$key] );
 243         }
 244
 245         /**
 246          * Get a cache item.
 247          *
 248          * Warning: this may be slow for split items (messages), since it will
 249          * need to fetch all of the subitems from the cache individually.
 250          * @param string $code
 251          * @param string $key
 252          * @return mixed
 253          */
 254         public function getItem( $code, $key ) {
 255                 if ( !isset( $this->loadedItems[$code][$key] ) ) {
 256                         wfProfileIn( __METHOD__ . '-load' );
 257                         $this->loadItem( $code, $key );
 258                         wfProfileOut( __METHOD__ . '-load' );
 259                 }
 260
 261                 if ( $key === 'fallback' && isset( $this->shallowFallbacks[$code] ) ) {
 262                         return $this->shallowFallbacks[$code];
 263                 }
 264
 265                 return $this->data[$code][$key];
 266         }
 267
 268         /**
 269          * Get a subitem, for instance a single message for a given language.
 270          * @param string $code
 271          * @param string $key
 272          * @param string $subkey
 273          * @return mixed|null
 274          */
 275         public function getSubitem( $code, $key, $subkey ) {
 276                 if ( !isset( $this->loadedSubitems[$code][$key][$subkey] ) &&
 277                         !isset( $this->loadedItems[$code][$key] )
 278                 ) {
 279                         wfProfileIn( __METHOD__ . '-load' );
 280                         $this->loadSubitem( $code, $key, $subkey );
 281                         wfProfileOut( __METHOD__ . '-load' );
 282                 }
 283
 284                 if ( isset( $this->data[$code][$key][$subkey] ) ) {
 285                         return $this->data[$code][$key][$subkey];
 286                 } else {
 287                         return null;
 288                 }
 289         }
 290
 291         /**
 292          * Get the list of subitem keys for a given item.
 293          *
 294          * This is faster than array_keys($lc->getItem(...)) for the items listed in
 295          * self::$splitKeys.
 296          *
 297          * Will return null if the item is not found, or false if the item is not an
 298          * array.
 299          * @param string $code
 300          * @param string $key
 301          * @return bool|null|string
 302          */
 303         public function getSubitemList( $code, $key ) {
 304                 if ( in_array( $key, self::$splitKeys ) ) {
 305                         return $this->getSubitem( $code, 'list', $key );
 306                 } else {
 307                         $item = $this->getItem( $code, $key );
 308                         if ( is_array( $item ) ) {
 309                                 return array_keys( $item );
 310                         } else {
 311                                 return false;
 312                         }
 313                 }
 314         }
 315
 316         /**
 317          * Load an item into the cache.
 318          * @param string $code
 319          * @param string $key
 320          */
 321         protected function loadItem( $code, $key ) {
 322                 if ( !isset( $this->initialisedLangs[$code] ) ) {
 323                         $this->initLanguage( $code );
 324                 }
 325
 326                 // Check to see if initLanguage() loaded it for us
 327                 if ( isset( $this->loadedItems[$code][$key] ) ) {
 328                         return;
 329                 }
 330
 331                 if ( isset( $this->shallowFallbacks[$code] ) ) {
 332                         $this->loadItem( $this->shallowFallbacks[$code], $key );
 333
 334                         return;
 335                 }
 336
 337                 if ( in_array( $key, self::$splitKeys ) ) {
 338                         $subkeyList = $this->getSubitem( $code, 'list', $key );
 339                         foreach ( $subkeyList as $subkey ) {
 340                                 if ( isset( $this->data[$code][$key][$subkey] ) ) {
 341                                         continue;
 342                                 }
 343                                 $this->data[$code][$key][$subkey] = $this->getSubitem( $code, $key, $subkey );
 344                         }
 345                 } else {
 346                         $this->data[$code][$key] = $this->store->get( $code, $key );
 347                 }
 348
 349                 $this->loadedItems[$code][$key] = true;
 350         }
 351
 352         /**
 353          * Load a subitem into the cache
 354          * @param string $code
 355          * @param string $key
 356          * @param string $subkey
 357          */
 358         protected function loadSubitem( $code, $key, $subkey ) {
 359                 if ( !in_array( $key, self::$splitKeys ) ) {
 360                         $this->loadItem( $code, $key );
 361
 362                         return;
 363                 }
 364
 365                 if ( !isset( $this->initialisedLangs[$code] ) ) {
 366                         $this->initLanguage( $code );
 367                 }
 368
 369                 // Check to see if initLanguage() loaded it for us
 370                 if ( isset( $this->loadedItems[$code][$key] ) ||
 371                         isset( $this->loadedSubitems[$code][$key][$subkey] )
 372                 ) {
 373                         return;
 374                 }
 375
 376                 if ( isset( $this->shallowFallbacks[$code] ) ) {
 377                         $this->loadSubitem( $this->shallowFallbacks[$code], $key, $subkey );
 378
 379                         return;
 380                 }
 381
 382                 $value = $this->store->get( $code, "$key:$subkey" );
 383                 $this->data[$code][$key][$subkey] = $value;
 384                 $this->loadedSubitems[$code][$key][$subkey] = true;
 385         }
 386
 387         /**
 388          * Returns true if the cache identified by $code is missing or expired.
 389          *
 390          * @param string $code
 391          *
 392          * @return bool
 393          */
 394         public function isExpired( $code ) {
 395                 if ( $this->forceRecache && !isset( $this->recachedLangs[$code] ) ) {
 396                         wfDebug( __METHOD__ . "($code): forced reload\n" );
 397
 398                         return true;
 399                 }
 400
 401                 $deps = $this->store->get( $code, 'deps' );
 402                 $keys = $this->store->get( $code, 'list' );
 403                 $preload = $this->store->get( $code, 'preload' );
 404                 // Different keys may expire separately for some stores
 405                 if ( $deps === null || $keys === null || $preload === null ) {
 406                         wfDebug( __METHOD__ . "($code): cache missing, need to make one\n" );
 407
 408                         return true;
 409                 }
 410
 411                 foreach ( $deps as $dep ) {
 412                         // Because we're unserializing stuff from cache, we
 413                         // could receive objects of classes that don't exist
 414                         // anymore (e.g. uninstalled extensions)
 415                         // When this happens, always expire the cache
 416                         if ( !$dep instanceof CacheDependency || $dep->isExpired() ) {
 417                                 wfDebug( __METHOD__ . "($code): cache for $code expired due to " .
 418                                         get_class( $dep ) . "\n" );
 419
 420                                 return true;
 421                         }
 422                 }
 423
 424                 return false;
 425         }
 426
 427         /**
 428          * Initialise a language in this object. Rebuild the cache if necessary.
 429          * @param string $code
 430          * @throws MWException
 431          */
 432         protected function initLanguage( $code ) {
 433                 if ( isset( $this->initialisedLangs[$code] ) ) {
 434                         return;
 435                 }
 436
 437                 $this->initialisedLangs[$code] = true;
 438
 439                 # If the code is of the wrong form for a Messages*.php file, do a shallow fallback
 440                 if ( !Language::isValidBuiltInCode( $code ) ) {
 441                         $this->initShallowFallback( $code, 'en' );
 442
 443                         return;
 444                 }
 445
 446                 # Recache the data if necessary
 447                 if ( !$this->manualRecache && $this->isExpired( $code ) ) {
 448                         if ( Language::isSupportedLanguage( $code ) ) {
 449                                 $this->recache( $code );
 450                         } elseif ( $code === 'en' ) {
 451                                 throw new MWException( 'MessagesEn.php is missing.' );
 452                         } else {
 453                                 $this->initShallowFallback( $code, 'en' );
 454                         }
 455
 456                         return;
 457                 }
 458
 459                 # Preload some stuff
 460                 $preload = $this->getItem( $code, 'preload' );
 461                 if ( $preload === null ) {
 462                         if ( $this->manualRecache ) {
 463                                 // No Messages*.php file. Do shallow fallback to en.
 464                                 if ( $code === 'en' ) {
 465                                         throw new MWException( 'No localisation cache found for English. ' .
 466                                                 'Please run maintenance/rebuildLocalisationCache.php.' );
 467                                 }
 468                                 $this->initShallowFallback( $code, 'en' );
 469
 470                                 return;
 471                         } else {
 472                                 throw new MWException( 'Invalid or missing localisation cache.' );
 473                         }
 474                 }
 475                 $this->data[$code] = $preload;
 476                 foreach ( $preload as $key => $item ) {
 477                         if ( in_array( $key, self::$splitKeys ) ) {
 478                                 foreach ( $item as $subkey => $subitem ) {
 479                                         $this->loadedSubitems[$code][$key][$subkey] = true;
 480                                 }
 481                         } else {
 482                                 $this->loadedItems[$code][$key] = true;
 483                         }
 484                 }
 485         }
 486
 487         /**
 488          * Create a fallback from one language to another, without creating a
 489          * complete persistent cache.
 490          * @param string $primaryCode
 491          * @param string $fallbackCode
 492          */
 493         public function initShallowFallback( $primaryCode, $fallbackCode ) {
 494                 $this->data[$primaryCode] =& $this->data[$fallbackCode];
 495                 $this->loadedItems[$primaryCode] =& $this->loadedItems[$fallbackCode];
 496                 $this->loadedSubitems[$primaryCode] =& $this->loadedSubitems[$fallbackCode];
 497                 $this->shallowFallbacks[$primaryCode] = $fallbackCode;
 498         }
 499
 500         /**
 501          * Read a PHP file containing localisation data.
 502          * @param string $_fileName
 503          * @param string $_fileType
 504          * @throws MWException
 505          * @return array
 506          */
 507         protected function readPHPFile( $_fileName, $_fileType ) {
 508                 wfProfileIn( __METHOD__ );
 509                 // Disable APC caching
 510                 wfSuppressWarnings();
 511                 $_apcEnabled = ini_set( 'apc.cache_by_default', '0' );
 512                 wfRestoreWarnings();
 513
 514                 include $_fileName;
 515
 516                 wfSuppressWarnings();
 517                 ini_set( 'apc.cache_by_default', $_apcEnabled );
 518                 wfRestoreWarnings();
 519
 520                 if ( $_fileType == 'core' || $_fileType == 'extension' ) {
 521                         $data = compact( self::$allKeys );
 522                 } elseif ( $_fileType == 'aliases' ) {
 523                         $data = compact( 'aliases' );
 524                 } else {
 525                         wfProfileOut( __METHOD__ );
 526                         throw new MWException( __METHOD__ . ": Invalid file type: $_fileType" );
 527                 }
 528                 wfProfileOut( __METHOD__ );
 529
 530                 return $data;
 531         }
 532
 533         /**
 534          * Read a JSON file containing localisation messages.
 535          * @param string $fileName Name of file to read
 536          * @throws MWException If there is a syntax error in the JSON file
 537          * @return array Array with a 'messages' key, or empty array if the file doesn't exist
 538          */
 539         public function readJSONFile( $fileName ) {
 540                 wfProfileIn( __METHOD__ );
 541
 542                 if ( !is_readable( $fileName ) ) {
 543                         wfProfileOut( __METHOD__ );
 544
 545                         return array();
 546                 }
 547
 548                 $json = file_get_contents( $fileName );
 549                 if ( $json === false ) {
 550                         wfProfileOut( __METHOD__ );
 551
 552                         return array();
 553                 }
 554
 555                 $data = FormatJson::decode( $json, true );
 556                 if ( $data === null ) {
 557                         wfProfileOut( __METHOD__ );
 558
 559                         throw new MWException( __METHOD__ . ": Invalid JSON file: $fileName" );
 560                 }
 561
 562                 // Remove keys starting with '@', they're reserved for metadata and non-message data
 563                 foreach ( $data as $key => $unused ) {
 564                         if ( $key === '' || $key[0] === '@' ) {
 565                                 unset( $data[$key] );
 566                         }
 567                 }
 568
 569                 wfProfileOut( __METHOD__ );
 570
 571                 // The JSON format only supports messages, none of the other variables, so wrap the data
 572                 return array( 'messages' => $data );
 573         }
 574
 575         /**
 576          * Get the compiled plural rules for a given language from the XML files.
 577          * @since 1.20
 578          * @param string $code
 579          * @return array|null
 580          */
 581         public function getCompiledPluralRules( $code ) {
 582                 $rules = $this->getPluralRules( $code );
 583                 if ( $rules === null ) {
 584                         return null;
 585                 }
 586                 try {
 587                         $compiledRules = CLDRPluralRuleEvaluator::compile( $rules );
 588                 } catch ( CLDRPluralRuleError $e ) {
 589                         wfDebugLog( 'l10n', $e->getMessage() );
 590
 591                         return array();
 592                 }
 593
 594                 return $compiledRules;
 595         }
 596
 597         /**
 598          * Get the plural rules for a given language from the XML files.
 599          * Cached.
 600          * @since 1.20
 601          * @param string $code
 602          * @return array|null
 603          */
 604         public function getPluralRules( $code ) {
 605                 if ( $this->pluralRules === null ) {
 606                         $this->loadPluralFiles();
 607                 }
 608                 if ( !isset( $this->pluralRules[$code] ) ) {
 609                         return null;
 610                 } else {
 611                         return $this->pluralRules[$code];
 612                 }
 613         }
 614
 615         /**
 616          * Get the plural rule types for a given language from the XML files.
 617          * Cached.
 618          * @since 1.22
 619          * @param string $code
 620          * @return array|null
 621          */
 622         public function getPluralRuleTypes( $code ) {
 623                 if ( $this->pluralRuleTypes === null ) {
 624                         $this->loadPluralFiles();
 625                 }
 626                 if ( !isset( $this->pluralRuleTypes[$code] ) ) {
 627                         return null;
 628                 } else {
 629                         return $this->pluralRuleTypes[$code];
 630                 }
 631         }
 632
 633         /**
 634          * Load the plural XML files.
 635          */
 636         protected function loadPluralFiles() {
 637                 global $IP;
 638                 $cldrPlural = "$IP/languages/data/plurals.xml";
 639                 $mwPlural = "$IP/languages/data/plurals-mediawiki.xml";
 640                 // Load CLDR plural rules
 641                 $this->loadPluralFile( $cldrPlural );
 642                 if ( file_exists( $mwPlural ) ) {
 643                         // Override or extend
 644                         $this->loadPluralFile( $mwPlural );
 645                 }
 646         }
 647
 648         /**
 649          * Load a plural XML file with the given filename, compile the relevant
 650          * rules, and save the compiled rules in a process-local cache.
 651          *
 652          * @param string $fileName
 653          */
 654         protected function loadPluralFile( $fileName ) {
 655                 $doc = new DOMDocument;
 656                 $doc->load( $fileName );
 657                 $rulesets = $doc->getElementsByTagName( "pluralRules" );
 658                 foreach ( $rulesets as $ruleset ) {
 659                         $codes = $ruleset->getAttribute( 'locales' );
 660                         $rules = array();
 661                         $ruleTypes = array();
 662                         $ruleElements = $ruleset->getElementsByTagName( "pluralRule" );
 663                         foreach ( $ruleElements as $elt ) {
 664                                 $ruleType = $elt->getAttribute( 'count' );
 665                                 if ( $ruleType === 'other' ) {
 666                                         // Don't record "other" rules, which have an empty condition
 667                                         continue;
 668                                 }
 669                                 $rules[] = $elt->nodeValue;
 670                                 $ruleTypes[] = $ruleType;
 671                         }
 672                         foreach ( explode( ' ', $codes ) as $code ) {
 673                                 $this->pluralRules[$code] = $rules;
 674                                 $this->pluralRuleTypes[$code] = $ruleTypes;
 675                         }
 676                 }
 677         }
 678
 679         /**
 680          * Read the data from the source files for a given language, and register
 681          * the relevant dependencies in the $deps array. If the localisation
 682          * exists, the data array is returned, otherwise false is returned.
 683          *
 684          * @param string $code
 685          * @param array $deps
 686          * @return array
 687          */
 688         protected function readSourceFilesAndRegisterDeps( $code, &$deps ) {
 689                 global $IP;
 690                 wfProfileIn( __METHOD__ );
 691
 692                 // This reads in the PHP i18n file with non-messages l10n data
 693                 $fileName = Language::getMessagesFileName( $code );
 694                 if ( !file_exists( $fileName ) ) {
 695                         $data = array();
 696                 } else {
 697                         $deps[] = new FileDependency( $fileName );
 698                         $data = $this->readPHPFile( $fileName, 'core' );
 699                 }
 700
 701                 # Load CLDR plural rules for JavaScript
 702                 $data['pluralRules'] = $this->getPluralRules( $code );
 703                 # And for PHP
 704                 $data['compiledPluralRules'] = $this->getCompiledPluralRules( $code );
 705                 # Load plural rule types
 706                 $data['pluralRuleTypes'] = $this->getPluralRuleTypes( $code );
 707
 708                 $deps['plurals'] = new FileDependency( "$IP/languages/data/plurals.xml" );
 709                 $deps['plurals-mw'] = new FileDependency( "$IP/languages/data/plurals-mediawiki.xml" );
 710
 711                 wfProfileOut( __METHOD__ );
 712
 713                 return $data;
 714         }
 715
 716         /**
 717          * Merge two localisation values, a primary and a fallback, overwriting the
 718          * primary value in place.
 719          * @param string $key
 720          * @param mixed $value
 721          * @param mixed $fallbackValue
 722          */
 723         protected function mergeItem( $key, &$value, $fallbackValue ) {
 724                 if ( !is_null( $value ) ) {
 725                         if ( !is_null( $fallbackValue ) ) {
 726                                 if ( in_array( $key, self::$mergeableMapKeys ) ) {
 727                                         $value = $value + $fallbackValue;
 728                                 } elseif ( in_array( $key, self::$mergeableListKeys ) ) {
 729                                         $value = array_unique( array_merge( $fallbackValue, $value ) );
 730                                 } elseif ( in_array( $key, self::$mergeableAliasListKeys ) ) {
 731                                         $value = array_merge_recursive( $value, $fallbackValue );
 732                                 } elseif ( in_array( $key, self::$optionalMergeKeys ) ) {
 733                                         if ( !empty( $value['inherit'] ) ) {
 734                                                 $value = array_merge( $fallbackValue, $value );
 735                                         }
 736
 737                                         if ( isset( $value['inherit'] ) ) {
 738                                                 unset( $value['inherit'] );
 739                                         }
 740                                 } elseif ( in_array( $key, self::$magicWordKeys ) ) {
 741                                         $this->mergeMagicWords( $value, $fallbackValue );
 742                                 }
 743                         }
 744                 } else {
 745                         $value = $fallbackValue;
 746                 }
 747         }
 748
 749         /**
 750          * @param mixed $value
 751          * @param mixed $fallbackValue
 752          */
 753         protected function mergeMagicWords( &$value, $fallbackValue ) {
 754                 foreach ( $fallbackValue as $magicName => $fallbackInfo ) {
 755                         if ( !isset( $value[$magicName] ) ) {
 756                                 $value[$magicName] = $fallbackInfo;
 757                         } else {
 758                                 $oldSynonyms = array_slice( $fallbackInfo, 1 );
 759                                 $newSynonyms = array_slice( $value[$magicName], 1 );
 760                                 $synonyms = array_values( array_unique( array_merge(
 761                                         $newSynonyms, $oldSynonyms ) ) );
 762                                 $value[$magicName] = array_merge( array( $fallbackInfo[0] ), $synonyms );
 763                         }
 764                 }
 765         }
 766
 767         /**
 768          * Given an array mapping language code to localisation value, such as is
 769          * found in extension *.i18n.php files, iterate through a fallback sequence
 770          * to merge the given data with an existing primary value.
 771          *
 772          * Returns true if any data from the extension array was used, false
 773          * otherwise.
 774          * @param array $codeSequence
 775          * @param string $key
 776          * @param mixed $value
 777          * @param mixed $fallbackValue
 778          * @return bool
 779          */
 780         protected function mergeExtensionItem( $codeSequence, $key, &$value, $fallbackValue ) {
 781                 $used = false;
 782                 foreach ( $codeSequence as $code ) {
 783                         if ( isset( $fallbackValue[$code] ) ) {
 784                                 $this->mergeItem( $key, $value, $fallbackValue[$code] );
 785                                 $used = true;
 786                         }
 787                 }
 788
 789                 return $used;
 790         }
 791
 792         /**
 793          * Load localisation data for a given language for both core and extensions
 794          * and save it to the persistent cache store and the process cache
 795          * @param string $code
 796          * @throws MWException
 797          */
 798         public function recache( $code ) {
 799                 global $wgExtensionMessagesFiles, $wgMessagesDirs;
 800                 wfProfileIn( __METHOD__ );
 801
 802                 if ( !$code ) {
 803                         wfProfileOut( __METHOD__ );
 804                         throw new MWException( "Invalid language code requested" );
 805                 }
 806                 $this->recachedLangs[$code] = true;
 807
 808                 # Initial values
 809                 $initialData = array_combine(
 810                         self::$allKeys,
 811                         array_fill( 0, count( self::$allKeys ), null ) );
 812                 $coreData = $initialData;
 813                 $deps = array();
 814
 815                 # Load the primary localisation from the source file
 816                 $data = $this->readSourceFilesAndRegisterDeps( $code, $deps );
 817                 if ( $data === false ) {
 818                         wfDebug( __METHOD__ . ": no localisation file for $code, using fallback to en\n" );
 819                         $coreData['fallback'] = 'en';
 820                 } else {
 821                         wfDebug( __METHOD__ . ": got localisation for $code from source\n" );
 822
 823                         # Merge primary localisation
 824                         foreach ( $data as $key => $value ) {
 825                                 $this->mergeItem( $key, $coreData[$key], $value );
 826                         }
 827                 }
 828
 829                 # Fill in the fallback if it's not there already
 830                 if ( is_null( $coreData['fallback'] ) ) {
 831                         $coreData['fallback'] = $code === 'en' ? false : 'en';
 832                 }
 833                 if ( $coreData['fallback'] === false ) {
 834                         $coreData['fallbackSequence'] = array();
 835                 } else {
 836                         $coreData['fallbackSequence'] = array_map( 'trim', explode( ',', $coreData['fallback'] ) );
 837                         $len = count( $coreData['fallbackSequence'] );
 838
 839                         # Ensure that the sequence ends at en
 840                         if ( $coreData['fallbackSequence'][$len - 1] !== 'en' ) {
 841                                 $coreData['fallbackSequence'][] = 'en';
 842                         }
 843                 }
 844
 845                 $codeSequence = array_merge( array( $code ), $coreData['fallbackSequence'] );
 846
 847                 wfProfileIn( __METHOD__ . '-fallbacks' );
 848
 849                 # Load non-JSON localisation data for extensions
 850                 $extensionData = array_combine(
 851                         $codeSequence,
 852                         array_fill( 0, count( $codeSequence ), $initialData ) );
 853                 foreach ( $wgExtensionMessagesFiles as $extension => $fileName ) {
 854                         if ( isset( $wgMessagesDirs[$extension] ) ) {
 855                                 # This extension has JSON message data; skip the PHP shim
 856                                 continue;
 857                         }
 858
 859                         $data = $this->readPHPFile( $fileName, 'extension' );
 860                         $used = false;
 861
 862                         foreach ( $data as $key => $item ) {
 863                                 foreach ( $codeSequence as $csCode ) {
 864                                         if ( isset( $item[$csCode] ) ) {
 865                                                 $this->mergeItem( $key, $extensionData[$csCode][$key], $item[$csCode] );
 866                                                 $used = true;
 867                                         }
 868                                 }
 869                         }
 870
 871                         if ( $used ) {
 872                                 $deps[] = new FileDependency( $fileName );
 873                         }
 874                 }
 875
 876                 # Load the localisation data for each fallback, then merge it into the full array
 877                 $allData = $initialData;
 878                 foreach ( $codeSequence as $csCode ) {
 879                         $csData = $initialData;
 880
 881                         # Load core messages and the extension localisations.
 882                         foreach ( $wgMessagesDirs as $dirs ) {
 883                                 foreach ( (array)$dirs as $dir ) {
 884                                         $fileName = "$dir/$csCode.json";
 885                                         $data = $this->readJSONFile( $fileName );
 886
 887                                         foreach ( $data as $key => $item ) {
 888                                                 $this->mergeItem( $key, $csData[$key], $item );
 889                                         }
 890
 891                                         $deps[] = new FileDependency( $fileName );
 892                                 }
 893                         }
 894
 895                         # Merge non-JSON extension data
 896                         if ( isset( $extensionData[$csCode] ) ) {
 897                                 foreach ( $extensionData[$csCode] as $key => $item ) {
 898                                         $this->mergeItem( $key, $csData[$key], $item );
 899                                 }
 900                         }
 901
 902                         if ( $csCode === $code ) {
 903                                 # Merge core data into extension data
 904                                 foreach ( $coreData as $key => $item ) {
 905                                         $this->mergeItem( $key, $csData[$key], $item );
 906                                 }
 907                         } else {
 908                                 # Load the secondary localisation from the source file to
 909                                 # avoid infinite cycles on cyclic fallbacks
 910                                 $fbData = $this->readSourceFilesAndRegisterDeps( $csCode, $deps );
 911                                 if ( $fbData !== false ) {
 912                                         # Only merge the keys that make sense to merge
 913                                         foreach ( self::$allKeys as $key ) {
 914                                                 if ( !isset( $fbData[$key] ) ) {
 915                                                         continue;
 916                                                 }
 917
 918                                                 if ( is_null( $coreData[$key] ) || $this->isMergeableKey( $key ) ) {
 919                                                         $this->mergeItem( $key, $csData[$key], $fbData[$key] );
 920                                                 }
 921                                         }
 922                                 }
 923                         }
 924
 925                         # Allow extensions an opportunity to adjust the data for this
 926                         # fallback
 927                         wfRunHooks( 'LocalisationCacheRecacheFallback', array( $this, $csCode, &$csData ) );
 928
 929                         # Merge the data for this fallback into the final array
 930                         if ( $csCode === $code ) {
 931                                 $allData = $csData;
 932                         } else {
 933                                 foreach ( self::$allKeys as $key ) {
 934                                         if ( !isset( $csData[$key] ) ) {
 935                                                 continue;
 936                                         }
 937
 938                                         if ( is_null( $allData[$key] ) || $this->isMergeableKey( $key ) ) {
 939                                                 $this->mergeItem( $key, $allData[$key], $csData[$key] );
 940                                         }
 941                                 }
 942                         }
 943                 }
 944
 945                 wfProfileOut( __METHOD__ . '-fallbacks' );
 946
 947                 # Add cache dependencies for any referenced globals
 948                 $deps['wgExtensionMessagesFiles'] = new GlobalDependency( 'wgExtensionMessagesFiles' );
 949                 $deps['wgMessagesDirs'] = new GlobalDependency( 'wgMessagesDirs' );
 950                 $deps['version'] = new ConstantDependency( 'LocalisationCache::VERSION' );
 951
 952                 # Add dependencies to the cache entry
 953                 $allData['deps'] = $deps;
 954
 955                 # Replace spaces with underscores in namespace names
 956                 $allData['namespaceNames'] = str_replace( ' ', '_', $allData['namespaceNames'] );
 957
 958                 # And do the same for special page aliases. $page is an array.
 959                 foreach ( $allData['specialPageAliases'] as &$page ) {
 960                         $page = str_replace( ' ', '_', $page );
 961                 }
 962                 # Decouple the reference to prevent accidental damage
 963                 unset( $page );
 964
 965                 # If there were no plural rules, return an empty array
 966                 if ( $allData['pluralRules'] === null ) {
 967                         $allData['pluralRules'] = array();
 968                 }
 969                 if ( $allData['compiledPluralRules'] === null ) {
 970                         $allData['compiledPluralRules'] = array();
 971                 }
 972                 # If there were no plural rule types, return an empty array
 973                 if ( $allData['pluralRuleTypes'] === null ) {
 974                         $allData['pluralRuleTypes'] = array();
 975                 }
 976
 977                 # Set the list keys
 978                 $allData['list'] = array();
 979                 foreach ( self::$splitKeys as $key ) {
 980                         $allData['list'][$key] = array_keys( $allData[$key] );
 981                 }
 982                 # Run hooks
 983                 $purgeBlobs = true;
 984                 wfRunHooks( 'LocalisationCacheRecache', array( $this, $code, &$allData, &$purgeBlobs ) );
 985
 986                 if ( is_null( $allData['namespaceNames'] ) ) {
 987                         wfProfileOut( __METHOD__ );
 988                         throw new MWException( __METHOD__ . ': Localisation data failed sanity check! ' .
 989                                 'Check that your languages/messages/MessagesEn.php file is intact.' );
 990                 }
 991
 992                 # Set the preload key
 993                 $allData['preload'] = $this->buildPreload( $allData );
 994
 995                 # Save to the process cache and register the items loaded
 996                 $this->data[$code] = $allData;
 997                 foreach ( $allData as $key => $item ) {
 998                         $this->loadedItems[$code][$key] = true;
 999                 }
1000
1001                 # Save to the persistent cache
1002                 wfProfileIn( __METHOD__ . '-write' );
1003                 $this->store->startWrite( $code );
1004                 foreach ( $allData as $key => $value ) {
1005                         if ( in_array( $key, self::$splitKeys ) ) {
1006                                 foreach ( $value as $subkey => $subvalue ) {
1007                                         $this->store->set( "$key:$subkey", $subvalue );
1008                                 }
1009                         } else {
1010                                 $this->store->set( $key, $value );
1011                         }
1012                 }
1013                 $this->store->finishWrite();
1014                 wfProfileOut( __METHOD__ . '-write' );
1015
1016                 # Clear out the MessageBlobStore
1017                 # HACK: If using a null (i.e. disabled) storage backend, we
1018                 # can't write to the MessageBlobStore either
1019                 if ( $purgeBlobs && !$this->store instanceof LCStoreNull ) {
1020                         MessageBlobStore::getInstance()->clear();
1021                 }
1022
1023                 wfProfileOut( __METHOD__ );
1024         }
1025
1026         /**
1027          * Build the preload item from the given pre-cache data.
1028          *
1029          * The preload item will be loaded automatically, improving performance
1030          * for the commonly-requested items it contains.
1031          * @param array $data
1032          * @return array
1033          */
1034         protected function buildPreload( $data ) {
1035                 $preload = array( 'messages' => array() );
1036                 foreach ( self::$preloadedKeys as $key ) {
1037                         $preload[$key] = $data[$key];
1038                 }
1039
1040                 foreach ( $data['preloadedMessages'] as $subkey ) {
1041                         if ( isset( $data['messages'][$subkey] ) ) {
1042                                 $subitem = $data['messages'][$subkey];
1043                         } else {
1044                                 $subitem = null;
1045                         }
1046                         $preload['messages'][$subkey] = $subitem;
1047                 }
1048
1049                 return $preload;
1050         }
1051
1052         /**
1053          * Unload the data for a given language from the object cache.
1054          * Reduces memory usage.
1055          * @param string $code
1056          */
1057         public function unload( $code ) {
1058                 unset( $this->data[$code] );
1059                 unset( $this->loadedItems[$code] );
1060                 unset( $this->loadedSubitems[$code] );
1061                 unset( $this->initialisedLangs[$code] );
1062                 unset( $this->shallowFallbacks[$code] );
1063
1064                 foreach ( $this->shallowFallbacks as $shallowCode => $fbCode ) {
1065                         if ( $fbCode === $code ) {
1066                                 $this->unload( $shallowCode );
1067                         }
1068                 }
1069         }
1070
1071         /**
1072          * Unload all data
1073          */
1074         public function unloadAll() {
1075                 foreach ( $this->initialisedLangs as $lang => $unused ) {
1076                         $this->unload( $lang );
1077                 }
1078         }
1079
1080         /**
1081          * Disable the storage backend
1082          */
1083         public function disableBackend() {
1084                 $this->store = new LCStoreNull;
1085                 $this->manualRecache = false;
1086         }
1087 }
1088
1089 /**
1090  * Interface for the persistence layer of LocalisationCache.
1091  *
1092  * The persistence layer is two-level hierarchical cache. The first level
1093  * is the language, the second level is the item or subitem.
1094  *
1095  * Since the data for a whole language is rebuilt in one operation, it needs
1096  * to have a fast and atomic method for deleting or replacing all of the
1097  * current data for a given language. The interface reflects this bulk update
1098  * operation. Callers writing to the cache must first call startWrite(), then
1099  * will call set() a couple of thousand times, then will call finishWrite()
1100  * to commit the operation. When finishWrite() is called, the cache is
1101  * expected to delete all data previously stored for that language.
1102  *
1103  * The values stored are PHP variables suitable for serialize(). Implementations
1104  * of LCStore are responsible for serializing and unserializing.
1105  */
1106 interface LCStore {
1107         /**
1108          * Get a value.
1109          * @param string $code Language code
1110          * @param string $key Cache key
1111          */
1112         function get( $code, $key );
1113
1114         /**
1115          * Start a write transaction.
1116          * @param string $code Language code
1117          */
1118         function startWrite( $code );
1119
1120         /**
1121          * Finish a write transaction.
1122          */
1123         function finishWrite();
1124
1125         /**
1126          * Set a key to a given value. startWrite() must be called before this
1127          * is called, and finishWrite() must be called afterwards.
1128          * @param string $key
1129          * @param mixed $value
1130          */
1131         function set( $key, $value );
1132 }
1133
1134 /**
1135  * LCStore implementation which uses the standard DB functions to store data.
1136  * This will work on any MediaWiki installation.
1137  */
1138 class LCStoreDB implements LCStore {
1139         private $currentLang;
1140         private $writesDone = false;
1141
1142         /** @var DatabaseBase */
1143         private $dbw;
1144         /** @var array */
1145         private $batch = array();
1146
1147         private $readOnly = false;
1148
1149         public function get( $code, $key ) {
1150                 if ( $this->writesDone ) {
1151                         $db = wfGetDB( DB_MASTER );
1152                 } else {
1153                         $db = wfGetDB( DB_SLAVE );
1154                 }
1155                 $row = $db->selectRow( 'l10n_cache', array( 'lc_value' ),
1156                         array( 'lc_lang' => $code, 'lc_key' => $key ), __METHOD__ );
1157                 if ( $row ) {
1158                         return unserialize( $db->decodeBlob( $row->lc_value ) );
1159                 } else {
1160                         return null;
1161                 }
1162         }
1163
1164         public function startWrite( $code ) {
1165                 if ( $this->readOnly ) {
1166                         return;
1167                 } elseif ( !$code ) {
1168                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
1169                 }
1170
1171                 $this->dbw = wfGetDB( DB_MASTER );
1172
1173                 $this->currentLang = $code;
1174                 $this->batch = array();
1175         }
1176
1177         public function finishWrite() {
1178                 if ( $this->readOnly ) {
1179                         return;
1180                 } elseif ( is_null( $this->currentLang ) ) {
1181                         throw new MWException( __CLASS__ . ': must call startWrite() before finishWrite()' );
1182                 }
1183
1184                 $this->dbw->begin( __METHOD__ );
1185                 try {
1186                         $this->dbw->delete( 'l10n_cache',
1187                                 array( 'lc_lang' => $this->currentLang ), __METHOD__ );
1188                         foreach ( array_chunk( $this->batch, 500 ) as $rows ) {
1189                                 $this->dbw->insert( 'l10n_cache', $rows, __METHOD__ );
1190                         }
1191                         $this->writesDone = true;
1192                 } catch ( DBQueryError $e ) {
1193                         if ( $this->dbw->wasReadOnlyError() ) {
1194                                 $this->readOnly = true; // just avoid site down time
1195                         } else {
1196                                 throw $e;
1197                         }
1198                 }
1199                 $this->dbw->commit( __METHOD__ );
1200
1201                 $this->currentLang = null;
1202                 $this->batch = array();
1203         }
1204
1205         public function set( $key, $value ) {
1206                 if ( $this->readOnly ) {
1207                         return;
1208                 } elseif ( is_null( $this->currentLang ) ) {
1209                         throw new MWException( __CLASS__ . ': must call startWrite() before set()' );
1210                 }
1211
1212                 $this->batch[] = array(
1213                         'lc_lang' => $this->currentLang,
1214                         'lc_key' => $key,
1215                         'lc_value' => $this->dbw->encodeBlob( serialize( $value ) ) );
1216         }
1217 }
1218
1219 /**
1220  * LCStore implementation which stores data as a collection of CDB files in the
1221  * directory given by $wgCacheDirectory. If $wgCacheDirectory is not set, this
1222  * will throw an exception.
1223  *
1224  * Profiling indicates that on Linux, this implementation outperforms MySQL if
1225  * the directory is on a local filesystem and there is ample kernel cache
1226  * space. The performance advantage is greater when the DBA extension is
1227  * available than it is with the PHP port.
1228  *
1229  * See Cdb.php and http://cr.yp.to/cdb.html
1230  */
1231 class LCStoreCDB implements LCStore {
1232         /** @var CdbReader[] */
1233         private $readers;
1234
1235         /** @var CdbWriter */
1236         private $writer;
1237
1238         /** @var string Current language code */
1239         private $currentLang;
1240
1241         /** @var bool|string Cache directory. False if not set */
1242         private $directory;
1243
1244         function __construct( $conf = array() ) {
1245                 global $wgCacheDirectory;
1246
1247                 if ( isset( $conf['directory'] ) ) {
1248                         $this->directory = $conf['directory'];
1249                 } else {
1250                         $this->directory = $wgCacheDirectory;
1251                 }
1252         }
1253
1254         public function get( $code, $key ) {
1255                 if ( !isset( $this->readers[$code] ) ) {
1256                         $fileName = $this->getFileName( $code );
1257
1258                         $this->readers[$code] = false;
1259                         if ( file_exists( $fileName ) ) {
1260                                 try {
1261                                         $this->readers[$code] = CdbReader::open( $fileName );
1262                                 } catch ( CdbException $e ) {
1263                                         wfDebug( __METHOD__ . ": unable to open cdb file for reading\n" );
1264                                 }
1265                         }
1266                 }
1267
1268                 if ( !$this->readers[$code] ) {
1269                         return null;
1270                 } else {
1271                         $value = false;
1272                         try {
1273                                 $value = $this->readers[$code]->get( $key );
1274                         } catch ( CdbException $e ) {
1275                                 wfDebug( __METHOD__ . ": CdbException caught, error message was "
1276                                         . $e->getMessage() . "\n" );
1277                         }
1278                         if ( $value === false ) {
1279                                 return null;
1280                         }
1281
1282                         return unserialize( $value );
1283                 }
1284         }
1285
1286         public function startWrite( $code ) {
1287                 if ( !file_exists( $this->directory ) ) {
1288                         if ( !wfMkdirParents( $this->directory, null, __METHOD__ ) ) {
1289                                 throw new MWException( "Unable to create the localisation store " .
1290                                         "directory \"{$this->directory}\"" );
1291                         }
1292                 }
1293
1294                 // Close reader to stop permission errors on write
1295                 if ( !empty( $this->readers[$code] ) ) {
1296                         $this->readers[$code]->close();
1297                 }
1298
1299                 try {
1300                         $this->writer = CdbWriter::open( $this->getFileName( $code ) );
1301                 } catch ( CdbException $e ) {
1302                         throw new MWException( $e->getMessage() );
1303                 }
1304                 $this->currentLang = $code;
1305         }
1306
1307         public function finishWrite() {
1308                 // Close the writer
1309                 try {
1310                         $this->writer->close();
1311                 } catch ( CdbException $e ) {
1312                         throw new MWException( $e->getMessage() );
1313                 }
1314                 $this->writer = null;
1315                 unset( $this->readers[$this->currentLang] );
1316                 $this->currentLang = null;
1317         }
1318
1319         public function set( $key, $value ) {
1320                 if ( is_null( $this->writer ) ) {
1321                         throw new MWException( __CLASS__ . ': must call startWrite() before calling set()' );
1322                 }
1323                 try {
1324                         $this->writer->set( $key, serialize( $value ) );
1325                 } catch ( CdbException $e ) {
1326                         throw new MWException( $e->getMessage() );
1327                 }
1328         }
1329
1330         protected function getFileName( $code ) {
1331                 if ( strval( $code ) === '' || strpos( $code, '/' ) !== false ) {
1332                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
1333                 }
1334
1335                 return "{$this->directory}/l10n_cache-$code.cdb";
1336         }
1337 }
1338
1339 /**
1340  * Null store backend, used to avoid DB errors during install
1341  */
1342 class LCStoreNull implements LCStore {
1343         public function get( $code, $key ) {
1344                 return null;
1345         }
1346
1347         public function startWrite( $code ) {
1348         }
1349
1350         public function finishWrite() {
1351         }
1352
1353         public function set( $key, $value ) {
1354         }
1355 }
1356
1357 /**
1358  * A localisation cache optimised for loading large amounts of data for many
1359  * languages. Used by rebuildLocalisationCache.php.
1360  */
1361 class LocalisationCacheBulkLoad extends LocalisationCache {
1362         /**
1363          * A cache of the contents of data files.
1364          * Core files are serialized to avoid using ~1GB of RAM during a recache.
1365          */
1366         private $fileCache = array();
1367
1368         /**
1369          * Most recently used languages. Uses the linked-list aspect of PHP hashtables
1370          * to keep the most recently used language codes at the end of the array, and
1371          * the language codes that are ready to be deleted at the beginning.
1372          */
1373         private $mruLangs = array();
1374
1375         /**
1376          * Maximum number of languages that may be loaded into $this->data
1377          */
1378         private $maxLoadedLangs = 10;
1379
1380         /**
1381          * @param string $fileName
1382          * @param string $fileType
1383          * @return array|mixed
1384          */
1385         protected function readPHPFile( $fileName, $fileType ) {
1386                 $serialize = $fileType === 'core';
1387                 if ( !isset( $this->fileCache[$fileName][$fileType] ) ) {
1388                         $data = parent::readPHPFile( $fileName, $fileType );
1389
1390                         if ( $serialize ) {
1391                                 $encData = serialize( $data );
1392                         } else {
1393                                 $encData = $data;
1394                         }
1395
1396                         $this->fileCache[$fileName][$fileType] = $encData;
1397
1398                         return $data;
1399                 } elseif ( $serialize ) {
1400                         return unserialize( $this->fileCache[$fileName][$fileType] );
1401                 } else {
1402                         return $this->fileCache[$fileName][$fileType];
1403                 }
1404         }
1405
1406         /**
1407          * @param string $code
1408          * @param string $key
1409          * @return mixed
1410          */
1411         public function getItem( $code, $key ) {
1412                 unset( $this->mruLangs[$code] );
1413                 $this->mruLangs[$code] = true;
1414
1415                 return parent::getItem( $code, $key );
1416         }
1417
1418         /**
1419          * @param string $code
1420          * @param string $key
1421          * @param string $subkey
1422          * @return mixed
1423          */
1424         public function getSubitem( $code, $key, $subkey ) {
1425                 unset( $this->mruLangs[$code] );
1426                 $this->mruLangs[$code] = true;
1427
1428                 return parent::getSubitem( $code, $key, $subkey );
1429         }
1430
1431         /**
1432          * @param string $code
1433          */
1434         public function recache( $code ) {
1435                 parent::recache( $code );
1436                 unset( $this->mruLangs[$code] );
1437                 $this->mruLangs[$code] = true;
1438                 $this->trimCache();
1439         }
1440
1441         /**
1442          * @param string $code
1443          */
1444         public function unload( $code ) {
1445                 unset( $this->mruLangs[$code] );
1446                 parent::unload( $code );
1447         }
1448
1449         /**
1450          * Unload cached languages until there are less than $this->maxLoadedLangs
1451          */
1452         protected function trimCache() {
1453                 while ( count( $this->data ) > $this->maxLoadedLangs && count( $this->mruLangs ) ) {
1454                         reset( $this->mruLangs );
1455                         $code = key( $this->mruLangs );
1456                         wfDebug( __METHOD__ . ": unloading $code\n" );
1457                         $this->unload( $code );
1458                 }
1459         }
1460 }