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          * All item keys
  82          */
  83         static public $allKeys = array(
  84                 'fallback', 'namespaceNames', 'mathNames', 'bookstoreList',
  85                 'magicWords', 'messages', 'rtl', 'capitalizeAllNouns', 'digitTransformTable',
  86                 'separatorTransformTable', 'fallback8bitEncoding', 'linkPrefixExtension',
  87                 'defaultUserOptionOverrides', 'linkTrail', 'namespaceAliases',
  88                 'dateFormats', 'datePreferences', 'datePreferenceMigrationMap',
  89                 'defaultDateFormat', 'extraUserToggles', 'specialPageAliases',
  90                 'imageFiles', 'preloadedMessages',
  91         );
  92
  93         /**
  94          * Keys for items which consist of associative arrays, which may be merged
  95          * by a fallback sequence.
  96          */
  97         static public $mergeableMapKeys = array( 'messages', 'namespaceNames', 'mathNames',
  98                 'dateFormats', 'defaultUserOptionOverrides', 'magicWords', 'imageFiles',
  99                 'preloadedMessages',
 100         );
 101
 102         /**
 103          * Keys for items which are a numbered array.
 104          */
 105         static public $mergeableListKeys = array( 'extraUserToggles' );
 106
 107         /**
 108          * Keys for items which contain an array of arrays of equivalent aliases
 109          * for each subitem. The aliases may be merged by a fallback sequence.
 110          */
 111         static public $mergeableAliasListKeys = array( 'specialPageAliases' );
 112
 113         /**
 114          * Keys for items which contain an associative array, and may be merged if
 115          * the primary value contains the special array key "inherit". That array
 116          * key is removed after the first merge.
 117          */
 118         static public $optionalMergeKeys = array( 'bookstoreList' );
 119
 120         /**
 121          * Keys for items where the subitems are stored in the backend separately.
 122          */
 123         static public $splitKeys = array( 'messages' );
 124
 125         /**
 126          * Keys which are loaded automatically by initLanguage()
 127          */
 128         static public $preloadedKeys = array( 'dateFormats', 'namespaceNames',
 129                 'defaultUserOptionOverrides' );
 130
 131         /**
 132          * Constructor.
 133          * For constructor parameters, see the documentation in DefaultSettings.php
 134          * for $wgLocalisationCacheConf.
 135          */
 136         function __construct( $conf ) {
 137                 global $wgCacheDirectory;
 138
 139                 $this->conf = $conf;
 140                 $storeConf = array();
 141                 if ( !empty( $conf['storeClass'] ) ) {
 142                         $storeClass = $conf['storeClass'];
 143                 } else {
 144                         switch ( $conf['store'] ) {
 145                                 case 'files':
 146                                 case 'file':
 147                                         $storeClass = 'LCStore_CDB';
 148                                         break;
 149                                 case 'db':
 150                                         $storeClass = 'LCStore_DB';
 151                                         break;
 152                                 case 'detect':
 153                                         $storeClass = $wgCacheDirectory ? 'LCStore_CDB' : 'LCStore_DB';
 154                                         break;
 155                                 default:
 156                                         throw new MWException(
 157                                                 'Please set $wgLocalisationCacheConf[\'store\'] to something sensible.' );
 158                         }
 159                 }
 160
 161                 wfDebug( get_class( $this ) . ": using store $storeClass\n" );
 162                 if ( !empty( $conf['storeDirectory'] ) ) {
 163                         $storeConf['directory'] = $conf['storeDirectory'];
 164                 }
 165
 166                 $this->store = new $storeClass( $storeConf );
 167                 foreach ( array( 'manualRecache', 'forceRecache' ) as $var ) {
 168                         if ( isset( $conf[$var] ) ) {
 169                                 $this->$var = $conf[$var];
 170                         }
 171                 }
 172         }
 173
 174         /**
 175          * Returns true if the given key is mergeable, that is, if it is an associative
 176          * array which can be merged through a fallback sequence.
 177          */
 178         public function isMergeableKey( $key ) {
 179                 if ( !isset( $this->mergeableKeys ) ) {
 180                         $this->mergeableKeys = array_flip( array_merge(
 181                                 self::$mergeableMapKeys,
 182                                 self::$mergeableListKeys,
 183                                 self::$mergeableAliasListKeys,
 184                                 self::$optionalMergeKeys
 185                         ) );
 186                 }
 187                 return isset( $this->mergeableKeys[$key] );
 188         }
 189
 190         /**
 191          * Get a cache item.
 192          *
 193          * Warning: this may be slow for split items (messages), since it will
 194          * need to fetch all of the subitems from the cache individually.
 195          */
 196         public function getItem( $code, $key ) {
 197                 if ( !isset( $this->loadedItems[$code][$key] ) ) {
 198                         wfProfileIn( __METHOD__.'-load' );
 199                         $this->loadItem( $code, $key );
 200                         wfProfileOut( __METHOD__.'-load' );
 201                 }
 202                 if ( $key === 'fallback' && isset( $this->shallowFallbacks[$code] ) ) {
 203                         return $this->shallowFallbacks[$code];
 204                 }
 205                 return $this->data[$code][$key];
 206         }
 207
 208         /**
 209          * Get a subitem, for instance a single message for a given language.
 210          */
 211         public function getSubitem( $code, $key, $subkey ) {
 212                 if ( !isset( $this->loadedSubitems[$code][$key][$subkey] )
 213                         && !isset( $this->loadedItems[$code][$key] ) )
 214                 {
 215                         wfProfileIn( __METHOD__.'-load' );
 216                         $this->loadSubitem( $code, $key, $subkey );
 217                         wfProfileOut( __METHOD__.'-load' );
 218                 }
 219                 if ( isset( $this->data[$code][$key][$subkey] ) ) {
 220                         return $this->data[$code][$key][$subkey];
 221                 } else {
 222                         return null;
 223                 }
 224         }
 225
 226         /**
 227          * Get the list of subitem keys for a given item.
 228          *
 229          * This is faster than array_keys($lc->getItem(...)) for the items listed in
 230          * self::$splitKeys.
 231          *
 232          * Will return null if the item is not found, or false if the item is not an
 233          * array.
 234          */
 235         public function getSubitemList( $code, $key ) {
 236                 if ( in_array( $key, self::$splitKeys ) ) {
 237                         return $this->getSubitem( $code, 'list', $key );
 238                 } else {
 239                         $item = $this->getItem( $code, $key );
 240                         if ( is_array( $item ) ) {
 241                                 return array_keys( $item );
 242                         } else {
 243                                 return false;
 244                         }
 245                 }
 246         }
 247
 248         /**
 249          * Load an item into the cache.
 250          */
 251         protected function loadItem( $code, $key ) {
 252                 if ( !isset( $this->initialisedLangs[$code] ) ) {
 253                         $this->initLanguage( $code );
 254                 }
 255                 // Check to see if initLanguage() loaded it for us
 256                 if ( isset( $this->loadedItems[$code][$key] ) ) {
 257                         return;
 258                 }
 259                 if ( isset( $this->shallowFallbacks[$code] ) ) {
 260                         $this->loadItem( $this->shallowFallbacks[$code], $key );
 261                         return;
 262                 }
 263                 if ( in_array( $key, self::$splitKeys ) ) {
 264                         $subkeyList = $this->getSubitem( $code, 'list', $key );
 265                         foreach ( $subkeyList as $subkey ) {
 266                                 if ( isset( $this->data[$code][$key][$subkey] ) ) {
 267                                         continue;
 268                                 }
 269                                 $this->data[$code][$key][$subkey] = $this->getSubitem( $code, $key, $subkey );
 270                         }
 271                 } else {
 272                         $this->data[$code][$key] = $this->store->get( $code, $key );
 273                 }
 274                 $this->loadedItems[$code][$key] = true;
 275         }
 276
 277         /**
 278          * Load a subitem into the cache
 279          */
 280         protected function loadSubitem( $code, $key, $subkey ) {
 281                 if ( !in_array( $key, self::$splitKeys ) ) {
 282                         $this->loadItem( $code, $key );
 283                         return;
 284                 }
 285                 if ( !isset( $this->initialisedLangs[$code] ) ) {
 286                         $this->initLanguage( $code );
 287                 }
 288                 // Check to see if initLanguage() loaded it for us
 289                 if ( isset( $this->loadedItems[$code][$key] )
 290                         || isset( $this->loadedSubitems[$code][$key][$subkey] ) )
 291                 {
 292                         return;
 293                 }
 294                 if ( isset( $this->shallowFallbacks[$code] ) ) {
 295                         $this->loadSubitem( $this->shallowFallbacks[$code], $key, $subkey );
 296                         return;
 297                 }
 298                 $value = $this->store->get( $code, "$key:$subkey" );
 299                 $this->data[$code][$key][$subkey] = $value;
 300                 $this->loadedSubitems[$code][$key][$subkey] = true;
 301         }
 302
 303         /**
 304          * Returns true if the cache identified by $code is missing or expired.
 305          */
 306         public function isExpired( $code ) {
 307                 if ( $this->forceRecache && !isset( $this->recachedLangs[$code] ) ) {
 308                         wfDebug( __METHOD__."($code): forced reload\n" );
 309                         return true;
 310                 }
 311
 312                 $deps = $this->store->get( $code, 'deps' );
 313                 if ( $deps === null ) {
 314                         wfDebug( __METHOD__."($code): cache missing, need to make one\n" );
 315                         return true;
 316                 }
 317                 foreach ( $deps as $dep ) {
 318                         // Because we're unserializing stuff from cache, we
 319                         // could receive objects of classes that don't exist
 320                         // anymore (e.g. uninstalled extensions)
 321                         // When this happens, always expire the cache
 322                         if ( !$dep instanceof CacheDependency || $dep->isExpired() ) {
 323                                 wfDebug( __METHOD__."($code): cache for $code expired due to " .
 324                                         get_class( $dep ) . "\n" );
 325                                 return true;
 326                         }
 327                 }
 328                 return false;
 329         }
 330
 331         /**
 332          * Initialise a language in this object. Rebuild the cache if necessary.
 333          */
 334         protected function initLanguage( $code ) {
 335                 if ( isset( $this->initialisedLangs[$code] ) ) {
 336                         return;
 337                 }
 338                 $this->initialisedLangs[$code] = true;
 339
 340                 # Recache the data if necessary
 341                 if ( !$this->manualRecache && $this->isExpired( $code ) ) {
 342                         if ( file_exists( Language::getMessagesFileName( $code ) ) ) {
 343                                 $this->recache( $code );
 344                         } elseif ( $code === 'en' ) {
 345                                 throw new MWException( 'MessagesEn.php is missing.' );
 346                         } else {
 347                                 $this->initShallowFallback( $code, 'en' );
 348                         }
 349                         return;
 350                 }
 351
 352                 # Preload some stuff
 353                 $preload = $this->getItem( $code, 'preload' );
 354                 if ( $preload === null ) {
 355                         if ( $this->manualRecache ) {
 356                                 // No Messages*.php file. Do shallow fallback to en.
 357                                 if ( $code === 'en' ) {
 358                                         throw new MWException( 'No localisation cache found for English. ' .
 359                                                 'Please run maintenance/rebuildLocalisationCache.php.' );
 360                                 }
 361                                 $this->initShallowFallback( $code, 'en' );
 362                                 return;
 363                         } else {
 364                                 throw new MWException( 'Invalid or missing localisation cache.' );
 365                         }
 366                 }
 367                 $this->data[$code] = $preload;
 368                 foreach ( $preload as $key => $item ) {
 369                         if ( in_array( $key, self::$splitKeys ) ) {
 370                                 foreach ( $item as $subkey => $subitem ) {
 371                                         $this->loadedSubitems[$code][$key][$subkey] = true;
 372                                 }
 373                         } else {
 374                                 $this->loadedItems[$code][$key] = true;
 375                         }
 376                 }
 377         }
 378
 379         /**
 380          * Create a fallback from one language to another, without creating a
 381          * complete persistent cache.
 382          */
 383         public function initShallowFallback( $primaryCode, $fallbackCode ) {
 384                 $this->data[$primaryCode] =& $this->data[$fallbackCode];
 385                 $this->loadedItems[$primaryCode] =& $this->loadedItems[$fallbackCode];
 386                 $this->loadedSubitems[$primaryCode] =& $this->loadedSubitems[$fallbackCode];
 387                 $this->shallowFallbacks[$primaryCode] = $fallbackCode;
 388         }
 389
 390         /**
 391          * Read a PHP file containing localisation data.
 392          */
 393         protected function readPHPFile( $_fileName, $_fileType ) {
 394                 // Disable APC caching
 395                 $_apcEnabled = ini_set( 'apc.cache_by_default', '0' );
 396                 include( $_fileName );
 397                 ini_set( 'apc.cache_by_default', $_apcEnabled );
 398
 399                 if ( $_fileType == 'core' || $_fileType == 'extension' ) {
 400                         $data = compact( self::$allKeys );
 401                 } elseif ( $_fileType == 'aliases' ) {
 402                         $data = compact( 'aliases' );
 403                 } else {
 404                         throw new MWException( __METHOD__.": Invalid file type: $_fileType" );
 405                 }
 406                 return $data;
 407         }
 408
 409         /**
 410          * Merge two localisation values, a primary and a fallback, overwriting the
 411          * primary value in place.
 412          */
 413         protected function mergeItem( $key, &$value, $fallbackValue ) {
 414                 if ( !is_null( $value ) ) {
 415                         if ( !is_null( $fallbackValue ) ) {
 416                                 if ( in_array( $key, self::$mergeableMapKeys ) ) {
 417                                         $value = $value + $fallbackValue;
 418                                 } elseif ( in_array( $key, self::$mergeableListKeys ) ) {
 419                                         $value = array_unique( array_merge( $fallbackValue, $value ) );
 420                                 } elseif ( in_array( $key, self::$mergeableAliasListKeys ) ) {
 421                                         $value = array_merge_recursive( $value, $fallbackValue );
 422                                 } elseif ( in_array( $key, self::$optionalMergeKeys ) ) {
 423                                         if ( !empty( $value['inherit'] ) )  {
 424                                                 $value = array_merge( $fallbackValue, $value );
 425                                         }
 426                                         if ( isset( $value['inherit'] ) ) {
 427                                                 unset( $value['inherit'] );
 428                                         }
 429                                 }
 430                         }
 431                 } else {
 432                         $value = $fallbackValue;
 433                 }
 434         }
 435
 436         /**
 437          * Given an array mapping language code to localisation value, such as is
 438          * found in extension *.i18n.php files, iterate through a fallback sequence
 439          * to merge the given data with an existing primary value.
 440          *
 441          * Returns true if any data from the extension array was used, false
 442          * otherwise.
 443          */
 444         protected function mergeExtensionItem( $codeSequence, $key, &$value, $fallbackValue ) {
 445                 $used = false;
 446                 foreach ( $codeSequence as $code ) {
 447                         if ( isset( $fallbackValue[$code] ) ) {
 448                                 $this->mergeItem( $key, $value, $fallbackValue[$code] );
 449                                 $used = true;
 450                         }
 451                 }
 452                 return $used;
 453         }
 454
 455         /**
 456          * Load localisation data for a given language for both core and extensions
 457          * and save it to the persistent cache store and the process cache
 458          */
 459         public function recache( $code ) {
 460                 static $recursionGuard = array();
 461                 global $wgExtensionMessagesFiles, $wgExtensionAliasesFiles;
 462                 wfProfileIn( __METHOD__ );
 463
 464                 if ( !$code ) {
 465                         throw new MWException( "Invalid language code requested" );
 466                 }
 467                 $this->recachedLangs[$code] = true;
 468
 469                 # Initial values
 470                 $initialData = array_combine(
 471                         self::$allKeys,
 472                         array_fill( 0, count( self::$allKeys ), null ) );
 473                 $coreData = $initialData;
 474                 $deps = array();
 475
 476                 # Load the primary localisation from the source file
 477                 $fileName = Language::getMessagesFileName( $code );
 478                 if ( !file_exists( $fileName ) ) {
 479                         wfDebug( __METHOD__.": no localisation file for $code, using fallback to en\n" );
 480                         $coreData['fallback'] = 'en';
 481                 } else {
 482                         $deps[] = new FileDependency( $fileName );
 483                         $data = $this->readPHPFile( $fileName, 'core' );
 484                         wfDebug( __METHOD__.": got localisation for $code from source\n" );
 485
 486                         # Merge primary localisation
 487                         foreach ( $data as $key => $value ) {
 488                                 $this->mergeItem( $key, $coreData[$key], $value );
 489                         }
 490                 }
 491
 492                 # Fill in the fallback if it's not there already
 493                 if ( is_null( $coreData['fallback'] ) ) {
 494                         $coreData['fallback'] = $code === 'en' ? false : 'en';
 495                 }
 496
 497                 if ( $coreData['fallback'] !== false ) {
 498                         # Guard against circular references
 499                         if ( isset( $recursionGuard[$code] ) ) {
 500                                 throw new MWException( "Error: Circular fallback reference in language code $code" );
 501                         }
 502                         $recursionGuard[$code] = true;
 503
 504                         # Load the fallback localisation item by item and merge it
 505                         $deps = array_merge( $deps, $this->getItem( $coreData['fallback'], 'deps' ) );
 506                         foreach ( self::$allKeys as $key ) {
 507                                 if ( is_null( $coreData[$key] ) || $this->isMergeableKey( $key ) ) {
 508                                         $fallbackValue = $this->getItem( $coreData['fallback'], $key );
 509                                         $this->mergeItem( $key, $coreData[$key], $fallbackValue );
 510                                 }
 511                         }
 512                         $fallbackSequence = $this->getItem( $coreData['fallback'], 'fallbackSequence' );
 513                         array_unshift( $fallbackSequence, $coreData['fallback'] );
 514                         $coreData['fallbackSequence'] = $fallbackSequence;
 515                         unset( $recursionGuard[$code] );
 516                 } else {
 517                         $coreData['fallbackSequence'] = array();
 518                 }
 519                 $codeSequence = array_merge( array( $code ), $coreData['fallbackSequence'] );
 520
 521                 # Load the extension localisations
 522                 # This is done after the core because we know the fallback sequence now.
 523                 # But it has a higher precedence for merging so that we can support things
 524                 # like site-specific message overrides.
 525                 $allData = $initialData;
 526                 foreach ( $wgExtensionMessagesFiles as $fileName ) {
 527                         $data = $this->readPHPFile( $fileName, 'extension' );
 528                         $used = false;
 529                         foreach ( $data as $key => $item ) {
 530                                 if( $this->mergeExtensionItem( $codeSequence, $key, $allData[$key], $item ) ) {
 531                                         $used = true;
 532                                 }
 533                         }
 534                         if ( $used ) {
 535                                 $deps[] = new FileDependency( $fileName );
 536                         }
 537                 }
 538
 539                 # Load deprecated $wgExtensionAliasesFiles
 540                 foreach ( $wgExtensionAliasesFiles as $fileName ) {
 541                         $data = $this->readPHPFile( $fileName, 'aliases' );
 542                         if ( !isset( $data['aliases'] ) ) {
 543                                 continue;
 544                         }
 545                         $used = $this->mergeExtensionItem( $codeSequence, 'specialPageAliases',
 546                                 $allData['specialPageAliases'], $data['aliases'] );
 547                         if ( $used ) {
 548                                 $deps[] = new FileDependency( $fileName );
 549                         }
 550                 }
 551
 552                 # Merge core data into extension data
 553                 foreach ( $coreData as $key => $item ) {
 554                         $this->mergeItem( $key, $allData[$key], $item );
 555                 }
 556
 557                 # Add cache dependencies for any referenced globals
 558                 $deps['wgExtensionMessagesFiles'] = new GlobalDependency( 'wgExtensionMessagesFiles' );
 559                 $deps['wgExtensionAliasesFiles'] = new GlobalDependency( 'wgExtensionAliasesFiles' );
 560                 $deps['version'] = new ConstantDependency( 'MW_LC_VERSION' );
 561
 562                 # Add dependencies to the cache entry
 563                 $allData['deps'] = $deps;
 564
 565                 # Replace spaces with underscores in namespace names
 566                 $allData['namespaceNames'] = str_replace( ' ', '_', $allData['namespaceNames'] );
 567
 568                 # And do the same for special page aliases. $page is an array.
 569                 foreach ( $allData['specialPageAliases'] as &$page ) {
 570                         $page = str_replace( ' ', '_', $page );
 571                 }
 572                 # Decouple the reference to prevent accidental damage
 573                 unset($page);
 574
 575                 # Fix broken defaultUserOptionOverrides
 576                 if ( !is_array( $allData['defaultUserOptionOverrides'] ) ) {
 577                         $allData['defaultUserOptionOverrides'] = array();
 578                 }
 579
 580                 # Set the list keys
 581                 $allData['list'] = array();
 582                 foreach ( self::$splitKeys as $key ) {
 583                         $allData['list'][$key] = array_keys( $allData[$key] );
 584                 }
 585
 586                 # Run hooks
 587                 wfRunHooks( 'LocalisationCacheRecache', array( $this, $code, &$allData ) );
 588
 589                 if ( is_null( $allData['defaultUserOptionOverrides'] ) ) {
 590                         throw new MWException( __METHOD__.': Localisation data failed sanity check! ' .
 591                                 'Check that your languages/messages/MessagesEn.php file is intact.' );
 592                 }
 593
 594                 # Set the preload key
 595                 $allData['preload'] = $this->buildPreload( $allData );
 596
 597                 # Save to the process cache and register the items loaded
 598                 $this->data[$code] = $allData;
 599                 foreach ( $allData as $key => $item ) {
 600                         $this->loadedItems[$code][$key] = true;
 601                 }
 602
 603                 # Save to the persistent cache
 604                 $this->store->startWrite( $code );
 605                 foreach ( $allData as $key => $value ) {
 606                         if ( in_array( $key, self::$splitKeys ) ) {
 607                                 foreach ( $value as $subkey => $subvalue ) {
 608                                         $this->store->set( "$key:$subkey", $subvalue );
 609                                 }
 610                         } else {
 611                                 $this->store->set( $key, $value );
 612                         }
 613                 }
 614                 $this->store->finishWrite();
 615
 616                 # Clear out the MessageBlobStore
 617                 # HACK: If using a null (i.e. disabled) storage backend, we
 618                 # can't write to the MessageBlobStore either
 619                 if ( !$this->store instanceof LCStore_Null ) {
 620                         MessageBlobStore::clear();
 621                 }
 622
 623                 wfProfileOut( __METHOD__ );
 624         }
 625
 626         /**
 627          * Build the preload item from the given pre-cache data.
 628          *
 629          * The preload item will be loaded automatically, improving performance
 630          * for the commonly-requested items it contains.
 631          */
 632         protected function buildPreload( $data ) {
 633                 $preload = array( 'messages' => array() );
 634                 foreach ( self::$preloadedKeys as $key ) {
 635                         $preload[$key] = $data[$key];
 636                 }
 637                 foreach ( $data['preloadedMessages'] as $subkey ) {
 638                         if ( isset( $data['messages'][$subkey] ) ) {
 639                                 $subitem = $data['messages'][$subkey];
 640                         } else {
 641                                 $subitem = null;
 642                         }
 643                         $preload['messages'][$subkey] = $subitem;
 644                 }
 645                 return $preload;
 646         }
 647
 648         /**
 649          * Unload the data for a given language from the object cache.
 650          * Reduces memory usage.
 651          */
 652         public function unload( $code ) {
 653                 unset( $this->data[$code] );
 654                 unset( $this->loadedItems[$code] );
 655                 unset( $this->loadedSubitems[$code] );
 656                 unset( $this->initialisedLangs[$code] );
 657                 foreach ( $this->shallowFallbacks as $shallowCode => $fbCode ) {
 658                         if ( $fbCode === $code ) {
 659                                 $this->unload( $shallowCode );
 660                         }
 661                 }
 662         }
 663
 664         /**
 665          * Unload all data
 666          */
 667         public function unloadAll() {
 668                 foreach ( $this->initialisedLangs as $lang => $unused ) {
 669                         $this->unload( $lang );
 670                 }
 671         }
 672
 673         /**
 674          * Disable the storage backend
 675          */
 676         public function disableBackend() {
 677                 $this->store = new LCStore_Null;
 678                 $this->manualRecache = false;
 679         }
 680 }
 681
 682 /**
 683  * Interface for the persistence layer of LocalisationCache.
 684  *
 685  * The persistence layer is two-level hierarchical cache. The first level
 686  * is the language, the second level is the item or subitem.
 687  *
 688  * Since the data for a whole language is rebuilt in one operation, it needs
 689  * to have a fast and atomic method for deleting or replacing all of the
 690  * current data for a given language. The interface reflects this bulk update
 691  * operation. Callers writing to the cache must first call startWrite(), then
 692  * will call set() a couple of thousand times, then will call finishWrite()
 693  * to commit the operation. When finishWrite() is called, the cache is
 694  * expected to delete all data previously stored for that language.
 695  *
 696  * The values stored are PHP variables suitable for serialize(). Implementations
 697  * of LCStore are responsible for serializing and unserializing.
 698  */
 699 interface LCStore {
 700         /**
 701          * Get a value.
 702          * @param $code Language code
 703          * @param $key Cache key
 704          */
 705         function get( $code, $key );
 706
 707         /**
 708          * Start a write transaction.
 709          * @param $code Language code
 710          */
 711         function startWrite( $code );
 712
 713         /**
 714          * Finish a write transaction.
 715          */
 716         function finishWrite();
 717
 718         /**
 719          * Set a key to a given value. startWrite() must be called before this
 720          * is called, and finishWrite() must be called afterwards.
 721          */
 722         function set( $key, $value );
 723
 724 }
 725
 726 /**
 727  * LCStore implementation which uses the standard DB functions to store data.
 728  * This will work on any MediaWiki installation.
 729  */
 730 class LCStore_DB implements LCStore {
 731         var $currentLang;
 732         var $writesDone = false;
 733         var $dbw, $batch;
 734         var $readOnly = false;
 735
 736         public function get( $code, $key ) {
 737                 if ( $this->writesDone ) {
 738                         $db = wfGetDB( DB_MASTER );
 739                 } else {
 740                         $db = wfGetDB( DB_SLAVE );
 741                 }
 742                 $row = $db->selectRow( 'l10n_cache', array( 'lc_value' ),
 743                         array( 'lc_lang' => $code, 'lc_key' => $key ), __METHOD__ );
 744                 if ( $row ) {
 745                         return unserialize( $row->lc_value );
 746                 } else {
 747                         return null;
 748                 }
 749         }
 750
 751         public function startWrite( $code ) {
 752                 if ( $this->readOnly ) {
 753                         return;
 754                 }
 755                 if ( !$code ) {
 756                         throw new MWException( __METHOD__.": Invalid language \"$code\"" );
 757                 }
 758                 $this->dbw = wfGetDB( DB_MASTER );
 759                 try {
 760                         $this->dbw->begin();
 761                         $this->dbw->delete( 'l10n_cache', array( 'lc_lang' => $code ), __METHOD__ );
 762                 } catch ( DBQueryError $e ) {
 763                         if ( $this->dbw->wasReadOnlyError() ) {
 764                                 $this->readOnly = true;
 765                                 $this->dbw->rollback();
 766                                 $this->dbw->ignoreErrors( false );
 767                                 return;
 768                         } else {
 769                                 throw $e;
 770                         }
 771                 }
 772                 $this->currentLang = $code;
 773                 $this->batch = array();
 774         }
 775
 776         public function finishWrite() {
 777                 if ( $this->readOnly ) {
 778                         return;
 779                 }
 780                 if ( $this->batch ) {
 781                         $this->dbw->insert( 'l10n_cache', $this->batch, __METHOD__ );
 782                 }
 783                 $this->dbw->commit();
 784                 $this->currentLang = null;
 785                 $this->dbw = null;
 786                 $this->batch = array();
 787                 $this->writesDone = true;
 788         }
 789
 790         public function set( $key, $value ) {
 791                 if ( $this->readOnly ) {
 792                         return;
 793                 }
 794                 if ( is_null( $this->currentLang ) ) {
 795                         throw new MWException( __CLASS__.': must call startWrite() before calling set()' );
 796                 }
 797                 $this->batch[] = array(
 798                         'lc_lang' => $this->currentLang,
 799                         'lc_key' => $key,
 800                         'lc_value' => serialize( $value ) );
 801                 if ( count( $this->batch ) >= 100 ) {
 802                         $this->dbw->insert( 'l10n_cache', $this->batch, __METHOD__ );
 803                         $this->batch = array();
 804                 }
 805         }
 806 }
 807
 808 /**
 809  * LCStore implementation which stores data as a collection of CDB files in the
 810  * directory given by $wgCacheDirectory. If $wgCacheDirectory is not set, this
 811  * will throw an exception.
 812  *
 813  * Profiling indicates that on Linux, this implementation outperforms MySQL if
 814  * the directory is on a local filesystem and there is ample kernel cache
 815  * space. The performance advantage is greater when the DBA extension is
 816  * available than it is with the PHP port.
 817  *
 818  * See Cdb.php and http://cr.yp.to/cdb.html
 819  */
 820 class LCStore_CDB implements LCStore {
 821         var $readers, $writer, $currentLang, $directory;
 822
 823         function __construct( $conf = array() ) {
 824                 global $wgCacheDirectory;
 825                 if ( isset( $conf['directory'] ) ) {
 826                         $this->directory = $conf['directory'];
 827                 } else {
 828                         $this->directory = $wgCacheDirectory;
 829                 }
 830         }
 831
 832         public function get( $code, $key ) {
 833                 if ( !isset( $this->readers[$code] ) ) {
 834                         $fileName = $this->getFileName( $code );
 835                         if ( !file_exists( $fileName ) ) {
 836                                 $this->readers[$code] = false;
 837                         } else {
 838                                 $this->readers[$code] = CdbReader::open( $fileName );
 839                         }
 840                 }
 841                 if ( !$this->readers[$code] ) {
 842                         return null;
 843                 } else {
 844                         $value = $this->readers[$code]->get( $key );
 845                         if ( $value === false ) {
 846                                 return null;
 847                         }
 848                         return unserialize( $value );
 849                 }
 850         }
 851
 852         public function startWrite( $code ) {
 853                 if ( !file_exists( $this->directory ) ) {
 854                         if ( !wfMkdirParents( $this->directory ) ) {
 855                                 throw new MWException( "Unable to create the localisation store " .
 856                                         "directory \"{$this->directory}\"" );
 857                         }
 858                 }
 859                 // Close reader to stop permission errors on write
 860                 if( !empty($this->readers[$code]) ) {
 861                         $this->readers[$code]->close();
 862                 }
 863                 $this->writer = CdbWriter::open( $this->getFileName( $code ) );
 864                 $this->currentLang = $code;
 865         }
 866
 867         public function finishWrite() {
 868                 // Close the writer
 869                 $this->writer->close();
 870                 $this->writer = null;
 871                 unset( $this->readers[$this->currentLang] );
 872                 $this->currentLang = null;
 873         }
 874
 875         public function set( $key, $value ) {
 876                 if ( is_null( $this->writer ) ) {
 877                         throw new MWException( __CLASS__.': must call startWrite() before calling set()' );
 878                 }
 879                 $this->writer->set( $key, serialize( $value ) );
 880         }
 881
 882         protected function getFileName( $code ) {
 883                 if ( !$code || strpos( $code, '/' ) !== false ) {
 884                         throw new MWException( __METHOD__.": Invalid language \"$code\"" );
 885                 }
 886                 return "{$this->directory}/l10n_cache-$code.cdb";
 887         }
 888 }
 889
 890 /**
 891  * Null store backend, used to avoid DB errors during install
 892  */
 893 class LCStore_Null implements LCStore {
 894         public function get( $code, $key ) {
 895                 return null;
 896         }
 897
 898         public function startWrite( $code ) {}
 899         public function finishWrite() {}
 900         public function set( $key, $value ) {}
 901 }
 902
 903 /**
 904  * A localisation cache optimised for loading large amounts of data for many
 905  * languages. Used by rebuildLocalisationCache.php.
 906  */
 907 class LocalisationCache_BulkLoad extends LocalisationCache {
 908         /**
 909          * A cache of the contents of data files.
 910          * Core files are serialized to avoid using ~1GB of RAM during a recache.
 911          */
 912         var $fileCache = array();
 913
 914         /**
 915          * Most recently used languages. Uses the linked-list aspect of PHP hashtables
 916          * to keep the most recently used language codes at the end of the array, and
 917          * the language codes that are ready to be deleted at the beginning.
 918          */
 919         var $mruLangs = array();
 920
 921         /**
 922          * Maximum number of languages that may be loaded into $this->data
 923          */
 924         var $maxLoadedLangs = 10;
 925
 926         protected function readPHPFile( $fileName, $fileType ) {
 927                 $serialize = $fileType === 'core';
 928                 if ( !isset( $this->fileCache[$fileName][$fileType] ) ) {
 929                         $data = parent::readPHPFile( $fileName, $fileType );
 930                         if ( $serialize ) {
 931                                 $encData = serialize( $data );
 932                         } else {
 933                                 $encData = $data;
 934                         }
 935                         $this->fileCache[$fileName][$fileType] = $encData;
 936                         return $data;
 937                 } elseif ( $serialize ) {
 938                         return unserialize( $this->fileCache[$fileName][$fileType] );
 939                 } else {
 940                         return $this->fileCache[$fileName][$fileType];
 941                 }
 942         }
 943
 944         public function getItem( $code, $key ) {
 945                 unset( $this->mruLangs[$code] );
 946                 $this->mruLangs[$code] = true;
 947                 return parent::getItem( $code, $key );
 948         }
 949
 950         public function getSubitem( $code, $key, $subkey ) {
 951                 unset( $this->mruLangs[$code] );
 952                 $this->mruLangs[$code] = true;
 953                 return parent::getSubitem( $code, $key, $subkey );
 954         }
 955
 956         public function recache( $code ) {
 957                 parent::recache( $code );
 958                 unset( $this->mruLangs[$code] );
 959                 $this->mruLangs[$code] = true;
 960                 $this->trimCache();
 961         }
 962
 963         public function unload( $code ) {
 964                 unset( $this->mruLangs[$code] );
 965                 parent::unload( $code );
 966         }
 967
 968         /**
 969          * Unload cached languages until there are less than $this->maxLoadedLangs
 970          */
 971         protected function trimCache() {
 972                 while ( count( $this->data ) > $this->maxLoadedLangs && count( $this->mruLangs ) ) {
 973                         reset( $this->mruLangs );
 974                         $code = key( $this->mruLangs );
 975                         wfDebug( __METHOD__.": unloading $code\n" );
 976                         $this->unload( $code );
 977                 }
 978         }
 979 }