includes/LocalisationCache.php

   1 <?php
   2
   3 define( 'MW_LC_VERSION', 1 );
   4
   5 /**
   6  * Class for caching the contents of localisation files, Messages*.php
   7  * and *.i18n.php.
   8  *
   9  * An instance of this class is available using Language::getLocalisationCache().
  10  *
  11  * The values retrieved from here are merged, containing items from extension
  12  * files, core messages files and the language fallback sequence (e.g. zh-cn ->
  13  * zh-hans -> en ). Some common errors are corrected, for example namespace
  14  * names with spaces instead of underscores, but heavyweight processing, such
  15  * as grammatical transformation, is done by the caller.
  16  */
  17 class LocalisationCache {
  18         /** Configuration associative array */
  19         var $conf;
  20
  21         /**
  22          * True if recaching should only be done on an explicit call to recache().
  23          * Setting this reduces the overhead of cache freshness checking, which
  24          * requires doing a stat() for every extension i18n file.
  25          */
  26         var $manualRecache = false;
  27
  28         /**
  29          * True to treat all files as expired until they are regenerated by this object.
  30          */
  31         var $forceRecache = false;
  32
  33         /**
  34          * The cache data. 3-d array, where the first key is the language code,
  35          * the second key is the item key e.g. 'messages', and the third key is
  36          * an item specific subkey index. Some items are not arrays and so for those
  37          * items, there are no subkeys.
  38          */
  39         var $data = array();
  40
  41         /**
  42          * The persistent store object. An instance of LCStore.
  43          */
  44         var $store;
  45
  46         /**
  47          * A 2-d associative array, code/key, where presence indicates that the item
  48          * is loaded. Value arbitrary.
  49          *
  50          * For split items, if set, this indicates that all of the subitems have been
  51          * loaded.
  52          */
  53         var $loadedItems = array();
  54
  55         /**
  56          * A 3-d associative array, code/key/subkey, where presence indicates that
  57          * the subitem is loaded. Only used for the split items, i.e. messages.
  58          */
  59         var $loadedSubitems = array();
  60
  61         /**
  62          * An array where presence of a key indicates that that language has been
  63          * initialised. Initialisation includes checking for cache expiry and doing
  64          * any necessary updates.
  65          */
  66         var $initialisedLangs = array();
  67
  68         /**
  69          * An array mapping non-existent pseudo-languages to fallback languages. This
  70          * is filled by initShallowFallback() when data is requested from a language
  71          * that lacks a Messages*.php file.
  72          */
  73         var $shallowFallbacks = array();
  74
  75         /**
  76          * An array where the keys are codes that have been recached by this instance.
  77          */
  78         var $recachedLangs = array();
  79
  80         /**
  81          * Data added by extensions using the deprecated $wgMessageCache->addMessages()
  82          * interface.
  83          */
  84         var $legacyData = array();
  85
  86         /**
  87          * All item keys
  88          */
  89         static public $allKeys = array(
  90                 'fallback', 'namespaceNames', 'mathNames', 'bookstoreList',
  91                 'magicWords', 'messages', 'rtl', 'capitalizeAllNouns', 'digitTransformTable',
  92                 'separatorTransformTable', 'fallback8bitEncoding', 'linkPrefixExtension',
  93                 'defaultUserOptionOverrides', 'linkTrail', 'namespaceAliases',
  94                 'dateFormats', 'datePreferences', 'datePreferenceMigrationMap',
  95                 'defaultDateFormat', 'extraUserToggles', 'specialPageAliases',
  96                 'imageFiles', 'preloadedMessages',
  97         );
  98
  99         /**
 100          * Keys for items which consist of associative arrays, which may be merged
 101          * by a fallback sequence.
 102          */
 103         static public $mergeableMapKeys = array( 'messages', 'namespaceNames', 'mathNames',
 104                 'dateFormats', 'defaultUserOptionOverrides', 'magicWords', 'imageFiles',
 105                 'preloadedMessages',
 106         );
 107
 108         /**
 109          * Keys for items which are a numbered array.
 110          */
 111         static public $mergeableListKeys = array( 'extraUserToggles' );
 112
 113         /**
 114          * Keys for items which contain an array of arrays of equivalent aliases
 115          * for each subitem. The aliases may be merged by a fallback sequence.
 116          */
 117         static public $mergeableAliasListKeys = array( 'specialPageAliases' );
 118
 119         /**
 120          * Keys for items which contain an associative array, and may be merged if
 121          * the primary value contains the special array key "inherit". That array
 122          * key is removed after the first merge.
 123          */
 124         static public $optionalMergeKeys = array( 'bookstoreList' );
 125
 126         /**
 127          * Keys for items where the subitems are stored in the backend separately.
 128          */
 129         static public $splitKeys = array( 'messages' );
 130
 131         /**
 132          * Keys which are loaded automatically by initLanguage()
 133          */
 134         static public $preloadedKeys = array( 'dateFormats', 'namespaceNames',
 135                 'defaultUserOptionOverrides' );
 136
 137         /**
 138          * Constructor.
 139          * For constructor parameters, see the documentation in DefaultSettings.php
 140          * for $wgLocalisationCacheConf.
 141          */
 142         function __construct( $conf ) {
 143                 global $wgCacheDirectory;
 144
 145                 $this->conf = $conf;
 146                 $storeConf = array();
 147                 if ( !empty( $conf['storeClass'] ) ) {
 148                         $storeClass = $conf['storeClass'];
 149                 } else {
 150                         switch ( $conf['store'] ) {
 151                                 case 'files':
 152                                 case 'file':
 153                                         $storeClass = 'LCStore_CDB';
 154                                         break;
 155                                 case 'db':
 156                                         $storeClass = 'LCStore_DB';
 157                                         break;
 158                                 case 'detect':
 159                                         $storeClass = $wgCacheDirectory ? 'LCStore_CDB' : 'LCStore_DB';
 160                                         break;
 161                                 default:
 162                                         throw new MWException(
 163                                                 'Please set $wgLocalisationCacheConf[\'store\'] to something sensible.' );
 164                         }
 165                 }
 166
 167                 wfDebug( get_class( $this ) . ": using store $storeClass\n" );
 168                 if ( !empty( $conf['storeDirectory'] ) ) {
 169                         $storeConf['directory'] = $conf['storeDirectory'];
 170                 }
 171
 172                 $this->store = new $storeClass( $storeConf );
 173                 foreach ( array( 'manualRecache', 'forceRecache' ) as $var ) {
 174                         if ( isset( $conf[$var] ) ) {
 175                                 $this->$var = $conf[$var];
 176                         }
 177                 }
 178         }
 179
 180         /**
 181          * Returns true if the given key is mergeable, that is, if it is an associative
 182          * array which can be merged through a fallback sequence.
 183          */
 184         public function isMergeableKey( $key ) {
 185                 if ( !isset( $this->mergeableKeys ) ) {
 186                         $this->mergeableKeys = array_flip( array_merge(
 187                                 self::$mergeableMapKeys,
 188                                 self::$mergeableListKeys,
 189                                 self::$mergeableAliasListKeys,
 190                                 self::$optionalMergeKeys
 191                         ) );
 192                 }
 193                 return isset( $this->mergeableKeys[$key] );
 194         }
 195
 196         /**
 197          * Get a cache item.
 198          *
 199          * Warning: this may be slow for split items (messages), since it will
 200          * need to fetch all of the subitems from the cache individually.
 201          */
 202         public function getItem( $code, $key ) {
 203                 if ( !isset( $this->loadedItems[$code][$key] ) ) {
 204                         wfProfileIn( __METHOD__.'-load' );
 205                         $this->loadItem( $code, $key );
 206                         wfProfileOut( __METHOD__.'-load' );
 207                 }
 208                 if ( $key === 'fallback' && isset( $this->shallowFallbacks[$code] ) ) {
 209                         return $this->shallowFallbacks[$code];
 210                 }
 211                 return $this->data[$code][$key];
 212         }
 213
 214         /**
 215          * Get a subitem, for instance a single message for a given language.
 216          */
 217         public function getSubitem( $code, $key, $subkey ) {
 218                 if ( isset( $this->legacyData[$code][$key][$subkey] ) ) {
 219                         return $this->legacyData[$code][$key][$subkey];
 220                 }
 221                 if ( !isset( $this->loadedSubitems[$code][$key][$subkey] )
 222                         && !isset( $this->loadedItems[$code][$key] ) )
 223                 {
 224                         wfProfileIn( __METHOD__.'-load' );
 225                         $this->loadSubitem( $code, $key, $subkey );
 226                         wfProfileOut( __METHOD__.'-load' );
 227                 }
 228                 if ( isset( $this->data[$code][$key][$subkey] ) ) {
 229                         return $this->data[$code][$key][$subkey];
 230                 } else {
 231                         return null;
 232                 }
 233         }
 234
 235         /**
 236          * Load an item into the cache.
 237          */
 238         protected function loadItem( $code, $key ) {
 239                 if ( !isset( $this->initialisedLangs[$code] ) ) {
 240                         $this->initLanguage( $code );
 241                 }
 242                 // Check to see if initLanguage() loaded it for us
 243                 if ( isset( $this->loadedItems[$code][$key] ) ) {
 244                         return;
 245                 }
 246                 if ( isset( $this->shallowFallbacks[$code] ) ) {
 247                         $this->loadItem( $this->shallowFallbacks[$code], $key );
 248                         return;
 249                 }
 250                 if ( in_array( $key, self::$splitKeys ) ) {
 251                         $subkeyList = $this->getSubitem( $code, 'list', $key );
 252                         foreach ( $subkeyList as $subkey ) {
 253                                 if ( isset( $this->data[$code][$key][$subkey] ) ) {
 254                                         continue;
 255                                 }
 256                                 $this->data[$code][$key][$subkey] = $this->getSubitem( $code, $key, $subkey );
 257                         }
 258                 } else {
 259                         $this->data[$code][$key] = $this->store->get( $code, $key );
 260                 }
 261                 $this->loadedItems[$code][$key] = true;
 262         }
 263
 264         /**
 265          * Load a subitem into the cache
 266          */
 267         protected function loadSubitem( $code, $key, $subkey ) {
 268                 if ( !in_array( $key, self::$splitKeys ) ) {
 269                         $this->loadItem( $code, $key );
 270                         return;
 271                 }
 272                 if ( !isset( $this->initialisedLangs[$code] ) ) {
 273                         $this->initLanguage( $code );
 274                 }
 275                 // Check to see if initLanguage() loaded it for us
 276                 if ( isset( $this->loadedItems[$code][$key] )
 277                         || isset( $this->loadedSubitems[$code][$key][$subkey] ) )
 278                 {
 279                         return;
 280                 }
 281                 if ( isset( $this->shallowFallbacks[$code] ) ) {
 282                         $this->loadSubitem( $this->shallowFallbacks[$code], $key, $subkey );
 283                         return;
 284                 }
 285                 $value = $this->store->get( $code, "$key:$subkey" );
 286                 $this->data[$code][$key][$subkey] = $value;
 287                 $this->loadedSubitems[$code][$key][$subkey] = true;
 288         }
 289
 290         /**
 291          * Returns true if the cache identified by $code is missing or expired.
 292          */
 293         public function isExpired( $code ) {
 294                 if ( $this->forceRecache && !isset( $this->recachedLangs[$code] ) ) {
 295                         wfDebug( __METHOD__."($code): forced reload\n" );
 296                         return true;
 297                 }
 298
 299                 $deps = $this->store->get( $code, 'deps' );
 300                 if ( $deps === null ) {
 301                         wfDebug( __METHOD__."($code): cache missing, need to make one\n" );
 302                         return true;
 303                 }
 304                 foreach ( $deps as $dep ) {
 305                         // Because we're unserializing stuff from cache, we
 306                         // could receive objects of classes that don't exist
 307                         // anymore (e.g. uninstalled extensions)
 308                         // When this happens, always expire the cache
 309                         if ( !$dep instanceof CacheDependency || $dep->isExpired() ) {
 310                                 wfDebug( __METHOD__."($code): cache for $code expired due to " .
 311                                         get_class( $dep ) . "\n" );
 312                                 return true;
 313                         }
 314                 }
 315                 return false;
 316         }
 317
 318         /**
 319          * Initialise a language in this object. Rebuild the cache if necessary.
 320          */
 321         protected function initLanguage( $code ) {
 322                 if ( isset( $this->initialisedLangs[$code] ) ) {
 323                         return;
 324                 }
 325                 $this->initialisedLangs[$code] = true;
 326
 327                 # Recache the data if necessary
 328                 if ( !$this->manualRecache && $this->isExpired( $code ) ) {
 329                         if ( file_exists( Language::getMessagesFileName( $code ) ) ) {
 330                                 $this->recache( $code );
 331                         } elseif ( $code === 'en' ) {
 332                                 throw new MWException( 'MessagesEn.php is missing.' );
 333                         } else {
 334                                 $this->initShallowFallback( $code, 'en' );
 335                         }
 336                         return;
 337                 }
 338
 339                 # Preload some stuff
 340                 $preload = $this->getItem( $code, 'preload' );
 341                 if ( $preload === null ) {
 342                         if ( $this->manualRecache ) {
 343                                 // No Messages*.php file. Do shallow fallback to en.
 344                                 if ( $code === 'en' ) {
 345                                         throw new MWException( 'No localisation cache found for English. ' .
 346                                                 'Please run maintenance/rebuildLocalisationCache.php.' );
 347                                 }
 348                                 $this->initShallowFallback( $code, 'en' );
 349                                 return;
 350                         } else {
 351                                 throw new MWException( 'Invalid or missing localisation cache.' );
 352                         }
 353                 }
 354                 $this->data[$code] = $preload;
 355                 foreach ( $preload as $key => $item ) {
 356                         if ( in_array( $key, self::$splitKeys ) ) {
 357                                 foreach ( $item as $subkey => $subitem ) {
 358                                         $this->loadedSubitems[$code][$key][$subkey] = true;
 359                                 }
 360                         } else {
 361                                 $this->loadedItems[$code][$key] = true;
 362                         }
 363                 }
 364         }
 365
 366         /**
 367          * Create a fallback from one language to another, without creating a
 368          * complete persistent cache.
 369          */
 370         public function initShallowFallback( $primaryCode, $fallbackCode ) {
 371                 $this->data[$primaryCode] =& $this->data[$fallbackCode];
 372                 $this->loadedItems[$primaryCode] =& $this->loadedItems[$fallbackCode];
 373                 $this->loadedSubitems[$primaryCode] =& $this->loadedSubitems[$fallbackCode];
 374                 $this->shallowFallbacks[$primaryCode] = $fallbackCode;
 375         }
 376
 377         /**
 378          * Read a PHP file containing localisation data.
 379          */
 380         protected function readPHPFile( $_fileName, $_fileType ) {
 381                 // Disable APC caching
 382                 $_apcEnabled = ini_set( 'apc.cache_by_default', '0' );
 383                 include( $_fileName );
 384                 ini_set( 'apc.cache_by_default', $_apcEnabled );
 385
 386                 if ( $_fileType == 'core' || $_fileType == 'extension' ) {
 387                         $data = compact( self::$allKeys );
 388                 } elseif ( $_fileType == 'aliases' ) {
 389                         $data = compact( 'aliases' );
 390                 } else {
 391                         throw new MWException( __METHOD__.": Invalid file type: $_fileType" );
 392                 }
 393                 return $data;
 394         }
 395
 396         /**
 397          * Merge two localisation values, a primary and a fallback, overwriting the
 398          * primary value in place.
 399          */
 400         protected function mergeItem( $key, &$value, $fallbackValue ) {
 401                 if ( !is_null( $value ) ) {
 402                         if ( !is_null( $fallbackValue ) ) {
 403                                 if ( in_array( $key, self::$mergeableMapKeys ) ) {
 404                                         $value = $value + $fallbackValue;
 405                                 } elseif ( in_array( $key, self::$mergeableListKeys ) ) {
 406                                         $value = array_unique( array_merge( $fallbackValue, $value ) );
 407                                 } elseif ( in_array( $key, self::$mergeableAliasListKeys ) ) {
 408                                         $value = array_merge_recursive( $value, $fallbackValue );
 409                                 } elseif ( in_array( $key, self::$optionalMergeKeys ) ) {
 410                                         if ( !empty( $value['inherit'] ) )  {
 411                                                 $value = array_merge( $fallbackValue, $value );
 412                                         }
 413                                         if ( isset( $value['inherit'] ) ) {
 414                                                 unset( $value['inherit'] );
 415                                         }
 416                                 }
 417                         }
 418                 } else {
 419                         $value = $fallbackValue;
 420                 }
 421         }
 422
 423         /**
 424          * Given an array mapping language code to localisation value, such as is
 425          * found in extension *.i18n.php files, iterate through a fallback sequence
 426          * to merge the given data with an existing primary value.
 427          *
 428          * Returns true if any data from the extension array was used, false
 429          * otherwise.
 430          */
 431         protected function mergeExtensionItem( $codeSequence, $key, &$value, $fallbackValue ) {
 432                 $used = false;
 433                 foreach ( $codeSequence as $code ) {
 434                         if ( isset( $fallbackValue[$code] ) ) {
 435                                 $this->mergeItem( $key, $value, $fallbackValue[$code] );
 436                                 $used = true;
 437                         }
 438                 }
 439                 return $used;
 440         }
 441
 442         /**
 443          * Load localisation data for a given language for both core and extensions
 444          * and save it to the persistent cache store and the process cache
 445          */
 446         public function recache( $code ) {
 447                 static $recursionGuard = array();
 448                 global $wgExtensionMessagesFiles, $wgExtensionAliasesFiles;
 449                 wfProfileIn( __METHOD__ );
 450
 451                 if ( !$code ) {
 452                         throw new MWException( "Invalid language code requested" );
 453                 }
 454                 $this->recachedLangs[$code] = true;
 455
 456                 # Initial values
 457                 $initialData = array_combine(
 458                         self::$allKeys,
 459                         array_fill( 0, count( self::$allKeys ), null ) );
 460                 $coreData = $initialData;
 461                 $deps = array();
 462
 463                 # Load the primary localisation from the source file
 464                 $fileName = Language::getMessagesFileName( $code );
 465                 if ( !file_exists( $fileName ) ) {
 466                         wfDebug( __METHOD__.": no localisation file for $code, using fallback to en\n" );
 467                         $coreData['fallback'] = 'en';
 468                 } else {
 469                         $deps[] = new FileDependency( $fileName );
 470                         $data = $this->readPHPFile( $fileName, 'core' );
 471                         wfDebug( __METHOD__.": got localisation for $code from source\n" );
 472
 473                         # Merge primary localisation
 474                         foreach ( $data as $key => $value ) {
 475                                 $this->mergeItem( $key, $coreData[$key], $value );
 476                         }
 477                 }
 478
 479                 # Fill in the fallback if it's not there already
 480                 if ( is_null( $coreData['fallback'] ) ) {
 481                         $coreData['fallback'] = $code === 'en' ? false : 'en';
 482                 }
 483
 484                 if ( $coreData['fallback'] !== false ) {
 485                         # Guard against circular references
 486                         if ( isset( $recursionGuard[$code] ) ) {
 487                                 throw new MWException( "Error: Circular fallback reference in language code $code" );
 488                         }
 489                         $recursionGuard[$code] = true;
 490
 491                         # Load the fallback localisation item by item and merge it
 492                         $deps = array_merge( $deps, $this->getItem( $coreData['fallback'], 'deps' ) );
 493                         foreach ( self::$allKeys as $key ) {
 494                                 if ( is_null( $coreData[$key] ) || $this->isMergeableKey( $key ) ) {
 495                                         $fallbackValue = $this->getItem( $coreData['fallback'], $key );
 496                                         $this->mergeItem( $key, $coreData[$key], $fallbackValue );
 497                                 }
 498                         }
 499                         $fallbackSequence = $this->getItem( $coreData['fallback'], 'fallbackSequence' );
 500                         array_unshift( $fallbackSequence, $coreData['fallback'] );
 501                         $coreData['fallbackSequence'] = $fallbackSequence;
 502                         unset( $recursionGuard[$code] );
 503                 } else {
 504                         $coreData['fallbackSequence'] = array();
 505                 }
 506                 $codeSequence = array_merge( array( $code ), $coreData['fallbackSequence'] );
 507
 508                 # Load the extension localisations
 509                 # This is done after the core because we know the fallback sequence now.
 510                 # But it has a higher precedence for merging so that we can support things
 511                 # like site-specific message overrides.
 512                 $allData = $initialData;
 513                 foreach ( $wgExtensionMessagesFiles as $fileName ) {
 514                         $data = $this->readPHPFile( $fileName, 'extension' );
 515                         $used = false;
 516                         foreach ( $data as $key => $item ) {
 517                                 if( $this->mergeExtensionItem( $codeSequence, $key, $allData[$key], $item ) ) {
 518                                         $used = true;
 519                                 }
 520                         }
 521                         if ( $used ) {
 522                                 $deps[] = new FileDependency( $fileName );
 523                         }
 524                 }
 525
 526                 # Load deprecated $wgExtensionAliasesFiles
 527                 foreach ( $wgExtensionAliasesFiles as $fileName ) {
 528                         $data = $this->readPHPFile( $fileName, 'aliases' );
 529                         if ( !isset( $data['aliases'] ) ) {
 530                                 continue;
 531                         }
 532                         $used = $this->mergeExtensionItem( $codeSequence, 'specialPageAliases',
 533                                 $allData['specialPageAliases'], $data['aliases'] );
 534                         if ( $used ) {
 535                                 $deps[] = new FileDependency( $fileName );
 536                         }
 537                 }
 538
 539                 # Merge core data into extension data
 540                 foreach ( $coreData as $key => $item ) {
 541                         $this->mergeItem( $key, $allData[$key], $item );
 542                 }
 543
 544                 # Add cache dependencies for any referenced globals
 545                 $deps['wgExtensionMessagesFiles'] = new GlobalDependency( 'wgExtensionMessagesFiles' );
 546                 $deps['wgExtensionAliasesFiles'] = new GlobalDependency( 'wgExtensionAliasesFiles' );
 547                 $deps['version'] = new ConstantDependency( 'MW_LC_VERSION' );
 548
 549                 # Add dependencies to the cache entry
 550                 $allData['deps'] = $deps;
 551
 552                 # Replace spaces with underscores in namespace names
 553                 $allData['namespaceNames'] = str_replace( ' ', '_', $allData['namespaceNames'] );
 554
 555                 # And do the same for special page aliases. $page is an array.
 556                 foreach ( $allData['specialPageAliases'] as &$page ) {
 557                         $page = str_replace( ' ', '_', $page );
 558                 }
 559                 # Decouple the reference to prevent accidental damage
 560                 unset($page);
 561
 562                 # Fix broken defaultUserOptionOverrides
 563                 if ( !is_array( $allData['defaultUserOptionOverrides'] ) ) {
 564                         $allData['defaultUserOptionOverrides'] = array();
 565                 }
 566
 567                 # Set the preload key
 568                 $allData['preload'] = $this->buildPreload( $allData );
 569
 570                 # Set the list keys
 571                 $allData['list'] = array();
 572                 foreach ( self::$splitKeys as $key ) {
 573                         $allData['list'][$key] = array_keys( $allData[$key] );
 574                 }
 575
 576                 # Run hooks
 577                 wfRunHooks( 'LocalisationCacheRecache', array( $this, $code, &$allData ) );
 578
 579                 if ( is_null( $allData['defaultUserOptionOverrides'] ) ) {
 580                         throw new MWException( __METHOD__.': Localisation data failed sanity check! ' .
 581                                 'Check that your languages/messages/MessagesEn.php file is intact.' );
 582                 }
 583
 584                 # Save to the process cache and register the items loaded
 585                 $this->data[$code] = $allData;
 586                 foreach ( $allData as $key => $item ) {
 587                         $this->loadedItems[$code][$key] = true;
 588                 }
 589
 590                 # Save to the persistent cache
 591                 $this->store->startWrite( $code );
 592                 foreach ( $allData as $key => $value ) {
 593                         if ( in_array( $key, self::$splitKeys ) ) {
 594                                 foreach ( $value as $subkey => $subvalue ) {
 595                                         $this->store->set( "$key:$subkey", $subvalue );
 596                                 }
 597                         } else {
 598                                 $this->store->set( $key, $value );
 599                         }
 600                 }
 601                 $this->store->finishWrite();
 602
 603                 wfProfileOut( __METHOD__ );
 604         }
 605
 606         /**
 607          * Build the preload item from the given pre-cache data.
 608          *
 609          * The preload item will be loaded automatically, improving performance
 610          * for the commonly-requested items it contains.
 611          */
 612         protected function buildPreload( $data ) {
 613                 $preload = array( 'messages' => array() );
 614                 foreach ( self::$preloadedKeys as $key ) {
 615                         $preload[$key] = $data[$key];
 616                 }
 617                 foreach ( $data['preloadedMessages'] as $subkey ) {
 618                         if ( isset( $data['messages'][$subkey] ) ) {
 619                                 $subitem = $data['messages'][$subkey];
 620                         } else {
 621                                 $subitem = null;
 622                         }
 623                         $preload['messages'][$subkey] = $subitem;
 624                 }
 625                 return $preload;
 626         }
 627
 628         /**
 629          * Unload the data for a given language from the object cache.
 630          * Reduces memory usage.
 631          */
 632         public function unload( $code ) {
 633                 unset( $this->data[$code] );
 634                 unset( $this->loadedItems[$code] );
 635                 unset( $this->loadedSubitems[$code] );
 636                 unset( $this->initialisedLangs[$code] );
 637                 // We don't unload legacyData because there's no way to get it back
 638                 // again, it's not really a cache
 639                 foreach ( $this->shallowFallbacks as $shallowCode => $fbCode ) {
 640                         if ( $fbCode === $code ) {
 641                                 $this->unload( $shallowCode );
 642                         }
 643                 }
 644         }
 645
 646         /**
 647          * Unload all data
 648          */
 649         public function unloadAll() {
 650                 foreach ( $this->initialisedLangs as $lang => $unused ) {
 651                         $this->unload( $lang );
 652                 }
 653         }
 654
 655         /**
 656          * Add messages to the cache, from an extension that has not yet been
 657          * migrated to $wgExtensionMessages or the LocalisationCacheRecache hook.
 658          * Called by deprecated function $wgMessageCache->addMessages().
 659          */
 660         public function addLegacyMessages( $messages ) {
 661                 foreach ( $messages as $lang => $langMessages ) {
 662                         if ( isset( $this->legacyData[$lang]['messages'] ) ) {
 663                                 $this->legacyData[$lang]['messages'] =
 664                                         $langMessages + $this->legacyData[$lang]['messages'];
 665                         } else {
 666                                 $this->legacyData[$lang]['messages'] = $langMessages;
 667                         }
 668                 }
 669         }
 670
 671         /**
 672          * Disable the storage backend
 673          */
 674         public function disableBackend() {
 675                 $this->store = new LCStore_Null;
 676                 $this->manualRecache = false;
 677         }
 678 }
 679
 680 /**
 681  * Interface for the persistence layer of LocalisationCache.
 682  *
 683  * The persistence layer is two-level hierarchical cache. The first level
 684  * is the language, the second level is the item or subitem.
 685  *
 686  * Since the data for a whole language is rebuilt in one operation, it needs
 687  * to have a fast and atomic method for deleting or replacing all of the
 688  * current data for a given language. The interface reflects this bulk update
 689  * operation. Callers writing to the cache must first call startWrite(), then
 690  * will call set() a couple of thousand times, then will call finishWrite()
 691  * to commit the operation. When finishWrite() is called, the cache is
 692  * expected to delete all data previously stored for that language.
 693  *
 694  * The values stored are PHP variables suitable for serialize(). Implementations
 695  * of LCStore are responsible for serializing and unserializing.
 696  */
 697 interface LCStore {
 698         /**
 699          * Get a value.
 700          * @param $code Language code
 701          * @param $key Cache key
 702          */
 703         public function get( $code, $key );
 704
 705         /**
 706          * Start a write transaction.
 707          * @param $code Language code
 708          */
 709         public function startWrite( $code );
 710
 711         /**
 712          * Finish a write transaction.
 713          */
 714         public function finishWrite();
 715
 716         /**
 717          * Set a key to a given value. startWrite() must be called before this
 718          * is called, and finishWrite() must be called afterwards.
 719          */
 720         public function set( $key, $value );
 721
 722 }
 723
 724 /**
 725  * LCStore implementation which uses the standard DB functions to store data.
 726  * This will work on any MediaWiki installation.
 727  */
 728 class LCStore_DB implements LCStore {
 729         var $currentLang;
 730         var $writesDone = false;
 731         var $dbw, $batch;
 732         var $readOnly = false;
 733
 734         public function get( $code, $key ) {
 735                 if ( $this->writesDone ) {
 736                         $db = wfGetDB( DB_MASTER );
 737                 } else {
 738                         $db = wfGetDB( DB_SLAVE );
 739                 }
 740                 $row = $db->selectRow( 'l10n_cache', array( 'lc_value' ),
 741                         array( 'lc_lang' => $code, 'lc_key' => $key ), __METHOD__ );
 742                 if ( $row ) {
 743                         return unserialize( $row->lc_value );
 744                 } else {
 745                         return null;
 746                 }
 747         }
 748
 749         public function startWrite( $code ) {
 750                 if ( $this->readOnly ) {
 751                         return;
 752                 }
 753                 if ( !$code ) {
 754                         throw new MWException( __METHOD__.": Invalid language \"$code\"" );
 755                 }
 756                 $this->dbw = wfGetDB( DB_MASTER );
 757                 try {
 758                         $this->dbw->begin();
 759                         $this->dbw->delete( 'l10n_cache', array( 'lc_lang' => $code ), __METHOD__ );
 760                 } catch ( DBQueryError $e ) {
 761                         if ( $this->dbw->wasReadOnlyError() ) {
 762                                 $this->readOnly = true;
 763                                 $this->dbw->rollback();
 764                                 $this->dbw->ignoreErrors( false );
 765                                 return;
 766                         } else {
 767                                 throw $e;
 768                         }
 769                 }
 770                 $this->currentLang = $code;
 771                 $this->batch = array();
 772         }
 773
 774         public function finishWrite() {
 775                 if ( $this->readOnly ) {
 776                         return;
 777                 }
 778                 if ( $this->batch ) {
 779                         $this->dbw->insert( 'l10n_cache', $this->batch, __METHOD__ );
 780                 }
 781                 $this->dbw->commit();
 782                 $this->currentLang = null;
 783                 $this->dbw = null;
 784                 $this->batch = array();
 785                 $this->writesDone = true;
 786         }
 787
 788         public function set( $key, $value ) {
 789                 if ( $this->readOnly ) {
 790                         return;
 791                 }
 792                 if ( is_null( $this->currentLang ) ) {
 793                         throw new MWException( __CLASS__.': must call startWrite() before calling set()' );
 794                 }
 795                 $this->batch[] = array(
 796                         'lc_lang' => $this->currentLang,
 797                         'lc_key' => $key,
 798                         'lc_value' => serialize( $value ) );
 799                 if ( count( $this->batch ) >= 100 ) {
 800                         $this->dbw->insert( 'l10n_cache', $this->batch, __METHOD__ );
 801                         $this->batch = array();
 802                 }
 803         }
 804 }
 805
 806 /**
 807  * LCStore implementation which stores data as a collection of CDB files in the
 808  * directory given by $wgCacheDirectory. If $wgCacheDirectory is not set, this
 809  * will throw an exception.
 810  *
 811  * Profiling indicates that on Linux, this implementation outperforms MySQL if
 812  * the directory is on a local filesystem and there is ample kernel cache
 813  * space. The performance advantage is greater when the DBA extension is
 814  * available than it is with the PHP port.
 815  *
 816  * See Cdb.php and http://cr.yp.to/cdb.html
 817  */
 818 class LCStore_CDB implements LCStore {
 819         var $readers, $writer, $currentLang, $directory;
 820
 821         function __construct( $conf = array() ) {
 822                 global $wgCacheDirectory;
 823                 if ( isset( $conf['directory'] ) ) {
 824                         $this->directory = $conf['directory'];
 825                 } else {
 826                         $this->directory = $wgCacheDirectory;
 827                 }
 828         }
 829
 830         public function get( $code, $key ) {
 831                 if ( !isset( $this->readers[$code] ) ) {
 832                         $fileName = $this->getFileName( $code );
 833                         if ( !file_exists( $fileName ) ) {
 834                                 $this->readers[$code] = false;
 835                         } else {
 836                                 $this->readers[$code] = CdbReader::open( $fileName );
 837                         }
 838                 }
 839                 if ( !$this->readers[$code] ) {
 840                         return null;
 841                 } else {
 842                         $value = $this->readers[$code]->get( $key );
 843                         if ( $value === false ) {
 844                                 return null;
 845                         }
 846                         return unserialize( $value );
 847                 }
 848         }
 849
 850         public function startWrite( $code ) {
 851                 if ( !file_exists( $this->directory ) ) {
 852                         if ( !wfMkdirParents( $this->directory ) ) {
 853                                 throw new MWException( "Unable to create the localisation store " .
 854                                         "directory \"{$this->directory}\"" );
 855                         }
 856                 }
 857                 // Close reader to stop permission errors on write
 858                 if( !empty($this->readers[$code]) ) {
 859                         $this->readers[$code]->close();
 860                 }
 861                 $this->writer = CdbWriter::open( $this->getFileName( $code ) );
 862                 $this->currentLang = $code;
 863         }
 864
 865         public function finishWrite() {
 866                 // Close the writer
 867                 $this->writer->close();
 868                 $this->writer = null;
 869                 unset( $this->readers[$this->currentLang] );
 870                 $this->currentLang = null;
 871         }
 872
 873         public function set( $key, $value ) {
 874                 if ( is_null( $this->writer ) ) {
 875                         throw new MWException( __CLASS__.': must call startWrite() before calling set()' );
 876                 }
 877                 $this->writer->set( $key, serialize( $value ) );
 878         }
 879
 880         protected function getFileName( $code ) {
 881                 if ( !$code || strpos( $code, '/' ) !== false ) {
 882                         throw new MWException( __METHOD__.": Invalid language \"$code\"" );
 883                 }
 884                 return "{$this->directory}/l10n_cache-$code.cdb";
 885         }
 886 }
 887
 888 /**
 889  * Null store backend, used to avoid DB errors during install
 890  */
 891 class LCStore_Null implements LCStore {
 892         public function get( $code, $key ) {
 893                 return null;
 894         }
 895
 896         public function startWrite( $code ) {}
 897         public function finishWrite() {}
 898         public function set( $key, $value ) {}
 899 }
 900
 901 /**
 902  * A localisation cache optimised for loading large amounts of data for many
 903  * languages. Used by rebuildLocalisationCache.php.
 904  */
 905 class LocalisationCache_BulkLoad extends LocalisationCache {
 906         /**
 907          * A cache of the contents of data files.
 908          * Core files are serialized to avoid using ~1GB of RAM during a recache.
 909          */
 910         var $fileCache = array();
 911
 912         /**
 913          * Most recently used languages. Uses the linked-list aspect of PHP hashtables
 914          * to keep the most recently used language codes at the end of the array, and
 915          * the language codes that are ready to be deleted at the beginning.
 916          */
 917         var $mruLangs = array();
 918
 919         /**
 920          * Maximum number of languages that may be loaded into $this->data
 921          */
 922         var $maxLoadedLangs = 10;
 923
 924         protected function readPHPFile( $fileName, $fileType ) {
 925                 $serialize = $fileType === 'core';
 926                 if ( !isset( $this->fileCache[$fileName][$fileType] ) ) {
 927                         $data = parent::readPHPFile( $fileName, $fileType );
 928                         if ( $serialize ) {
 929                                 $encData = serialize( $data );
 930                         } else {
 931                                 $encData = $data;
 932                         }
 933                         $this->fileCache[$fileName][$fileType] = $encData;
 934                         return $data;
 935                 } elseif ( $serialize ) {
 936                         return unserialize( $this->fileCache[$fileName][$fileType] );
 937                 } else {
 938                         return $this->fileCache[$fileName][$fileType];
 939                 }
 940         }
 941
 942         public function getItem( $code, $key ) {
 943                 unset( $this->mruLangs[$code] );
 944                 $this->mruLangs[$code] = true;
 945                 return parent::getItem( $code, $key );
 946         }
 947
 948         public function getSubitem( $code, $key, $subkey ) {
 949                 unset( $this->mruLangs[$code] );
 950                 $this->mruLangs[$code] = true;
 951                 return parent::getSubitem( $code, $key, $subkey );
 952         }
 953
 954         public function recache( $code ) {
 955                 parent::recache( $code );
 956                 unset( $this->mruLangs[$code] );
 957                 $this->mruLangs[$code] = true;
 958                 $this->trimCache();
 959         }
 960
 961         public function unload( $code ) {
 962                 unset( $this->mruLangs[$code] );
 963                 parent::unload( $code );
 964         }
 965
 966         /**
 967          * Unload cached languages until there are less than $this->maxLoadedLangs
 968          */
 969         protected function trimCache() {
 970                 while ( count( $this->data ) > $this->maxLoadedLangs && count( $this->mruLangs ) ) {
 971                         reset( $this->mruLangs );
 972                         $code = key( $this->mruLangs );
 973                         wfDebug( __METHOD__.": unloading $code\n" );
 974                         $this->unload( $code );
 975                 }
 976         }
 977 }