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 $wgLocalisationConf[\'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                         if ( isset( $this->loadedItems[$code][$key] ) ) {
 223                                 if ( isset( $this->data[$code][$key][$subkey] ) ) {
 224                                         return $this->data[$code][$key][$subkey];
 225                                 } else {
 226                                         return null;
 227                                 }
 228                         } else {
 229                                 wfProfileIn( __METHOD__.'-load' );
 230                                 $this->loadSubitem( $code, $key, $subkey );
 231                                 wfProfileOut( __METHOD__.'-load' );
 232                         }
 233                 }
 234                 return $this->data[$code][$key][$subkey];
 235         }
 236
 237         /**
 238          * Load an item into the cache.
 239          */
 240         protected function loadItem( $code, $key ) {
 241                 if ( !isset( $this->initialisedLangs[$code] ) ) {
 242                         $this->initLanguage( $code );
 243                 }
 244                 // Check to see if initLanguage() loaded it for us
 245                 if ( isset( $this->loadedItems[$code][$key] ) ) {
 246                         return;
 247                 }
 248                 if ( isset( $this->shallowFallbacks[$code] ) ) {
 249                         $this->loadItem( $this->shallowFallbacks[$code], $key );
 250                         return;
 251                 }
 252                 if ( in_array( $key, self::$splitKeys ) ) {
 253                         $subkeyList = $this->getSubitem( $code, 'list', $key );
 254                         foreach ( $subkeyList as $subkey ) {
 255                                 if ( isset( $this->data[$code][$key][$subkey] ) ) {
 256                                         continue;
 257                                 }
 258                                 $this->data[$code][$key][$subkey] = $this->getSubitem( $code, $key, $subkey );
 259                         }
 260                 } else {
 261                         $this->data[$code][$key] = $this->store->get( $code, $key );
 262                 }
 263                 $this->loadedItems[$code][$key] = true;
 264         }
 265
 266         /**
 267          * Load a subitem into the cache
 268          */
 269         protected function loadSubitem( $code, $key, $subkey ) {
 270                 if ( !in_array( $key, self::$splitKeys ) ) {
 271                         $this->loadItem( $code, $key );
 272                         return;
 273                 }
 274                 if ( !isset( $this->initialisedLangs[$code] ) ) {
 275                         $this->initLanguage( $code );
 276                 }
 277                 // Check to see if initLanguage() loaded it for us
 278                 if ( isset( $this->loadedSubitems[$code][$key][$subkey] ) ) {
 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                         if ( $dep->isExpired() ) {
 306                                 wfDebug( __METHOD__."($code): cache for $code expired due to " .
 307                                         get_class( $dep ) . "\n" );
 308                                 return true;
 309                         }
 310                 }
 311                 return false;
 312         }
 313
 314         /**
 315          * Initialise a language in this object. Rebuild the cache if necessary.
 316          */
 317         protected function initLanguage( $code ) {
 318                 if ( isset( $this->initialisedLangs[$code] ) ) {
 319                         return;
 320                 }
 321                 $this->initialisedLangs[$code] = true;
 322
 323                 # Recache the data if necessary
 324                 if ( !$this->manualRecache && $this->isExpired( $code ) ) {
 325                         if ( file_exists( Language::getMessagesFileName( $code ) ) ) {
 326                                 $this->recache( $code );
 327                         } elseif ( $code === 'en' ) {
 328                                 throw new MWException( 'MessagesEn.php is missing.' );
 329                         } else {
 330                                 $this->initShallowFallback( $code, 'en' );
 331                         }
 332                         return;
 333                 }
 334
 335                 # Preload some stuff
 336                 $preload = $this->getItem( $code, 'preload' );
 337                 if ( $preload === null ) {
 338                         if ( $this->manualRecache ) {
 339                                 // No Messages*.php file. Do shallow fallback to en.
 340                                 if ( $code === 'en' ) {
 341                                         throw new MWException( 'No localisation cache found for English. ' .
 342                                                 'Please run maintenance/rebuildLocalisationCache.php.' );
 343                                 }
 344                                 $this->initShallowFallback( $code, 'en' );
 345                                 return;
 346                         } else {
 347                                 throw new MWException( 'Invalid or missing localisation cache.' );
 348                         }
 349                 }
 350                 $this->data[$code] = $preload;
 351                 foreach ( $preload as $key => $item ) {
 352                         if ( in_array( $key, self::$splitKeys ) ) {
 353                                 foreach ( $item as $subkey => $subitem ) {
 354                                         $this->loadedSubitems[$code][$key][$subkey] = true;
 355                                 }
 356                         } else {
 357                                 $this->loadedItems[$code][$key] = true;
 358                         }
 359                 }
 360         }
 361
 362         /**
 363          * Create a fallback from one language to another, without creating a
 364          * complete persistent cache.
 365          */
 366         public function initShallowFallback( $primaryCode, $fallbackCode ) {
 367                 $this->data[$primaryCode] =& $this->data[$fallbackCode];
 368                 $this->loadedItems[$primaryCode] =& $this->loadedItems[$fallbackCode];
 369                 $this->loadedSubitems[$primaryCode] =& $this->loadedSubitems[$fallbackCode];
 370                 $this->shallowFallbacks[$primaryCode] = $fallbackCode;
 371         }
 372
 373         /**
 374          * Read a PHP file containing localisation data.
 375          */
 376         protected function readPHPFile( $_fileName, $_fileType ) {
 377                 // Disable APC caching
 378                 $_apcEnabled = ini_set( 'apc.enabled', '0' );
 379                 include( $_fileName );
 380                 ini_set( 'apc.enabled', $_apcEnabled );
 381
 382                 if ( $_fileType == 'core' || $_fileType == 'extension' ) {
 383                         $data = compact( self::$allKeys );
 384                 } elseif ( $_fileType == 'aliases' ) {
 385                         $data = compact( 'aliases' );
 386                 } else {
 387                         throw new MWException( __METHOD__.": Invalid file type: $_fileType" );
 388                 }
 389                 return $data;
 390         }
 391
 392         /**
 393          * Merge two localisation values, a primary and a fallback, overwriting the
 394          * primary value in place.
 395          */
 396         protected function mergeItem( $key, &$value, $fallbackValue ) {
 397                 if ( !is_null( $value ) ) {
 398                         if ( !is_null( $fallbackValue ) ) {
 399                                 if ( in_array( $key, self::$mergeableMapKeys ) ) {
 400                                         $value = $value + $fallbackValue;
 401                                 } elseif ( in_array( $key, self::$mergeableListKeys ) ) {
 402                                         $value = array_unique( array_merge( $fallbackValue, $value ) );
 403                                 } elseif ( in_array( $key, self::$mergeableAliasListKeys ) ) {
 404                                         $value = array_merge_recursive( $value, $fallbackValue );
 405                                 } elseif ( in_array( $key, self::$optionalMergeKeys ) ) {
 406                                         if ( !empty( $value['inherit'] ) )  {
 407                                                 $value = array_merge( $fallbackValue, $value );
 408                                         }
 409                                         if ( isset( $value['inherit'] ) ) {
 410                                                 unset( $value['inherit'] );
 411                                         }
 412                                 }
 413                         }
 414                 } else {
 415                         $value = $fallbackValue;
 416                 }
 417         }
 418
 419         /**
 420          * Given an array mapping language code to localisation value, such as is
 421          * found in extension *.i18n.php files, iterate through a fallback sequence
 422          * to merge the given data with an existing primary value.
 423          *
 424          * Returns true if any data from the extension array was used, false
 425          * otherwise.
 426          */
 427         protected function mergeExtensionItem( $codeSequence, $key, &$value, $fallbackValue ) {
 428                 $used = false;
 429                 foreach ( $codeSequence as $code ) {
 430                         if ( isset( $fallbackValue[$code] ) ) {
 431                                 $this->mergeItem( $key, $value, $fallbackValue[$code] );
 432                                 $used = true;
 433                         }
 434                 }
 435                 return $used;
 436         }
 437
 438         /**
 439          * Load localisation data for a given language for both core and extensions
 440          * and save it to the persistent cache store and the process cache
 441          */
 442         public function recache( $code ) {
 443                 static $recursionGuard = array();
 444                 global $wgExtensionMessagesFiles, $wgExtensionAliasesFiles;
 445                 wfProfileIn( __METHOD__ );
 446
 447                 if ( !$code ) {
 448                         throw new MWException( "Invalid language code requested" );
 449                 }
 450                 $this->recachedLangs[$code] = true;
 451
 452                 # Initial values
 453                 $initialData = array_combine(
 454                         self::$allKeys,
 455                         array_fill( 0, count( self::$allKeys ), null ) );
 456                 $coreData = $initialData;
 457                 $deps = array();
 458
 459                 # Load the primary localisation from the source file
 460                 $fileName = Language::getMessagesFileName( $code );
 461                 if ( !file_exists( $fileName ) ) {
 462                         wfDebug( __METHOD__.": no localisation file for $code, using fallback to en\n" );
 463                         $coreData['fallback'] = 'en';
 464                 } else {
 465                         $deps[] = new FileDependency( $fileName );
 466                         $data = $this->readPHPFile( $fileName, 'core' );
 467                         wfDebug( __METHOD__.": got localisation for $code from source\n" );
 468
 469                         # Merge primary localisation
 470                         foreach ( $data as $key => $value ) {
 471                                 $this->mergeItem( $key, $coreData[$key], $value );
 472                         }
 473                 }
 474
 475                 # Fill in the fallback if it's not there already
 476                 if ( is_null( $coreData['fallback'] ) ) {
 477                         $coreData['fallback'] = $code === 'en' ? false : 'en';
 478                 }
 479
 480                 if ( $coreData['fallback'] !== false ) {
 481                         # Guard against circular references
 482                         if ( isset( $recursionGuard[$code] ) ) {
 483                                 throw new MWException( "Error: Circular fallback reference in language code $code" );
 484                         }
 485                         $recursionGuard[$code] = true;
 486
 487                         # Load the fallback localisation item by item and merge it
 488                         $deps = array_merge( $deps, $this->getItem( $coreData['fallback'], 'deps' ) );
 489                         foreach ( self::$allKeys as $key ) {
 490                                 if ( is_null( $coreData[$key] ) || $this->isMergeableKey( $key ) ) {
 491                                         $fallbackValue = $this->getItem( $coreData['fallback'], $key );
 492                                         $this->mergeItem( $key, $coreData[$key], $fallbackValue );
 493                                 }
 494                         }
 495                         $fallbackSequence = $this->getItem( $coreData['fallback'], 'fallbackSequence' );
 496                         array_unshift( $fallbackSequence, $coreData['fallback'] );
 497                         $coreData['fallbackSequence'] = $fallbackSequence;
 498                         unset( $recursionGuard[$code] );
 499                 } else {
 500                         $coreData['fallbackSequence'] = array();
 501                 }
 502                 $codeSequence = array_merge( array( $code ), $coreData['fallbackSequence'] );
 503
 504                 # Load the extension localisations
 505                 # This is done after the core because we know the fallback sequence now.
 506                 # But it has a higher precedence for merging so that we can support things
 507                 # like site-specific message overrides.
 508                 $allData = $initialData;
 509                 foreach ( $wgExtensionMessagesFiles as $fileName ) {
 510                         $data = $this->readPHPFile( $fileName, 'extension' );
 511                         $used = false;
 512                         foreach ( $data as $key => $item ) {
 513                                 $used = $used |
 514                                         $this->mergeExtensionItem( $codeSequence, $key, $allData[$key], $item );
 515                         }
 516                         if ( $used ) {
 517                                 $deps[] = new FileDependency( $fileName );
 518                         }
 519                 }
 520
 521                 # Load deprecated $wgExtensionAliasesFiles
 522                 foreach ( $wgExtensionAliasesFiles as $fileName ) {
 523                         $data = $this->readPHPFile( $fileName, 'aliases' );
 524                         if ( !isset( $data['aliases'] ) ) {
 525                                 continue;
 526                         }
 527                         $used = $this->mergeExtensionItem( $codeSequence, 'specialPageAliases',
 528                                 $allData['specialPageAliases'], $data['aliases'] );
 529                         if ( $used ) {
 530                                 $deps[] = new FileDependency( $fileName );
 531                         }
 532                 }
 533
 534                 # Merge core data into extension data
 535                 foreach ( $coreData as $key => $item ) {
 536                         $this->mergeItem( $key, $allData[$key], $item );
 537                 }
 538
 539                 # Add cache dependencies for any referenced globals
 540                 $deps['wgExtensionMessagesFiles'] = new GlobalDependency( 'wgExtensionMessagesFiles' );
 541                 $deps['wgExtensionAliasesFiles'] = new GlobalDependency( 'wgExtensionAliasesFiles' );
 542                 $deps['version'] = new ConstantDependency( 'MW_LC_VERSION' );
 543
 544                 # Add dependencies to the cache entry
 545                 $allData['deps'] = $deps;
 546
 547                 # Replace spaces with underscores in namespace names
 548                 $allData['namespaceNames'] = str_replace( ' ', '_', $allData['namespaceNames'] );
 549
 550                 # And do the same for special page aliases. $page is an array.
 551                 foreach ( $allData['specialPageAliases'] as &$page ) {
 552                         $page = str_replace( ' ', '_', $page );
 553                 }
 554                 # Decouple the reference to prevent accidental damage
 555                 unset($page);
 556
 557                 # Fix broken defaultUserOptionOverrides
 558                 if ( !is_array( $allData['defaultUserOptionOverrides'] ) ) {
 559                         $allData['defaultUserOptionOverrides'] = array();
 560                 }
 561
 562                 # Set the preload key
 563                 $allData['preload'] = $this->buildPreload( $allData );
 564
 565                 # Set the list keys
 566                 $allData['list'] = array();
 567                 foreach ( self::$splitKeys as $key ) {
 568                         $allData['list'][$key] = array_keys( $allData[$key] );
 569                 }
 570
 571                 # Run hooks
 572                 wfRunHooks( 'LocalisationCacheRecache', array( $this, $code, &$allData ) );
 573
 574                 if ( is_null( $allData['defaultUserOptionOverrides'] ) ) {
 575                         throw new MWException( __METHOD__.': Localisation data failed sanity check! ' .
 576                                 'Check that your languages/messages/MessagesEn.php file is intact.' );
 577                 }
 578
 579                 # Save to the process cache and register the items loaded
 580                 $this->data[$code] = $allData;
 581                 foreach ( $allData as $key => $item ) {
 582                         $this->loadedItems[$code][$key] = true;
 583                 }
 584
 585                 # Save to the persistent cache
 586                 $this->store->startWrite( $code );
 587                 foreach ( $allData as $key => $value ) {
 588                         if ( in_array( $key, self::$splitKeys ) ) {
 589                                 foreach ( $value as $subkey => $subvalue ) {
 590                                         $this->store->set( "$key:$subkey", $subvalue );
 591                                 }
 592                         } else {
 593                                 $this->store->set( $key, $value );
 594                         }
 595                 }
 596                 $this->store->finishWrite();
 597
 598                 wfProfileOut( __METHOD__ );
 599         }
 600
 601         /**
 602          * Build the preload item from the given pre-cache data.
 603          *
 604          * The preload item will be loaded automatically, improving performance
 605          * for the commonly-requested items it contains.
 606          */
 607         protected function buildPreload( $data ) {
 608                 $preload = array( 'messages' => array() );
 609                 foreach ( self::$preloadedKeys as $key ) {
 610                         $preload[$key] = $data[$key];
 611                 }
 612                 foreach ( $data['preloadedMessages'] as $subkey ) {
 613                         if ( isset( $data['messages'][$subkey] ) ) {
 614                                 $subitem = $data['messages'][$subkey];
 615                         } else {
 616                                 $subitem = null;
 617                         }
 618                         $preload['messages'][$subkey] = $subitem;
 619                 }
 620                 return $preload;
 621         }
 622
 623         /**
 624          * Unload the data for a given language from the object cache.
 625          * Reduces memory usage.
 626          */
 627         public function unload( $code ) {
 628                 unset( $this->data[$code] );
 629                 unset( $this->loadedItems[$code] );
 630                 unset( $this->loadedSubitems[$code] );
 631                 unset( $this->initialisedLangs[$code] );
 632                 // We don't unload legacyData because there's no way to get it back
 633                 // again, it's not really a cache
 634                 foreach ( $this->shallowFallbacks as $shallowCode => $fbCode ) {
 635                         if ( $fbCode === $code ) {
 636                                 $this->unload( $shallowCode );
 637                         }
 638                 }
 639         }
 640
 641         /**
 642          * Add messages to the cache, from an extension that has not yet been
 643          * migrated to $wgExtensionMessages or the LocalisationCacheRecache hook.
 644          * Called by deprecated function $wgMessageCache->addMessages().
 645          */
 646         public function addLegacyMessages( $messages ) {
 647                 foreach ( $messages as $lang => $langMessages ) {
 648                         if ( isset( $this->legacyData[$lang]['messages'] ) ) {
 649                                 $this->legacyData[$lang]['messages'] =
 650                                         $langMessages + $this->legacyData[$lang]['messages'];
 651                         } else {
 652                                 $this->legacyData[$lang]['messages'] = $langMessages;
 653                         }
 654                 }
 655         }
 656
 657         /**
 658          * Disable the storage backend
 659          */
 660         public function disableBackend() {
 661                 $this->store = new LCStore_Null;
 662         }
 663 }
 664
 665 /**
 666  * Interface for the persistence layer of LocalisationCache.
 667  *
 668  * The persistence layer is two-level hierarchical cache. The first level
 669  * is the language, the second level is the item or subitem.
 670  *
 671  * Since the data for a whole language is rebuilt in one operation, it needs
 672  * to have a fast and atomic method for deleting or replacing all of the
 673  * current data for a given language. The interface reflects this bulk update
 674  * operation. Callers writing to the cache must first call startWrite(), then
 675  * will call set() a couple of thousand times, then will call finishWrite()
 676  * to commit the operation. When finishWrite() is called, the cache is
 677  * expected to delete all data previously stored for that language.
 678  *
 679  * The values stored are PHP variables suitable for serialize(). Implementations
 680  * of LCStore are responsible for serializing and unserializing.
 681  */
 682 interface LCStore {
 683         /**
 684          * Get a value.
 685          * @param $code Language code
 686          * @param $key Cache key
 687          */
 688         public function get( $code, $key );
 689
 690         /**
 691          * Start a write transaction.
 692          * @param $code Language code
 693          */
 694         public function startWrite( $code );
 695
 696         /**
 697          * Finish a write transaction.
 698          */
 699         public function finishWrite();
 700
 701         /**
 702          * Set a key to a given value. startWrite() must be called before this
 703          * is called, and finishWrite() must be called afterwards.
 704          */
 705         public function set( $key, $value );
 706
 707 }
 708
 709 /**
 710  * LCStore implementation which uses the standard DB functions to store data.
 711  * This will work on any MediaWiki installation.
 712  */
 713 class LCStore_DB implements LCStore {
 714         var $currentLang;
 715         var $writesDone = false;
 716         var $dbw, $batch;
 717
 718         public function get( $code, $key ) {
 719                 if ( $this->writesDone ) {
 720                         $db = wfGetDB( DB_MASTER );
 721                 } else {
 722                         $db = wfGetDB( DB_SLAVE );
 723                 }
 724                 $row = $db->selectRow( 'l10n_cache', array( 'lc_value' ),
 725                         array( 'lc_lang' => $code, 'lc_key' => $key ), __METHOD__ );
 726                 if ( $row ) {
 727                         return unserialize( $row->lc_value );
 728                 } else {
 729                         return null;
 730                 }
 731         }
 732
 733         public function startWrite( $code ) {
 734                 if ( !$code ) {
 735                         throw new MWException( __METHOD__.": Invalid language \"$code\"" );
 736                 }
 737                 $this->dbw = wfGetDB( DB_MASTER );
 738                 $this->dbw->begin();
 739                 $this->dbw->delete( 'l10n_cache', array( 'lc_lang' => $code ), __METHOD__ );
 740                 $this->currentLang = $code;
 741                 $this->batch = array();
 742         }
 743
 744         public function finishWrite() {
 745                 if ( $this->batch ) {
 746                         $this->dbw->insert( 'l10n_cache', $this->batch, __METHOD__ );
 747                 }
 748                 $this->dbw->commit();
 749                 $this->currentLang = null;
 750                 $this->dbw = null;
 751                 $this->batch = array();
 752                 $this->writesDone = true;
 753         }
 754
 755         public function set( $key, $value ) {
 756                 if ( is_null( $this->currentLang ) ) {
 757                         throw new MWException( __CLASS__.': must call startWrite() before calling set()' );
 758                 }
 759                 $this->batch[] = array(
 760                         'lc_lang' => $this->currentLang,
 761                         'lc_key' => $key,
 762                         'lc_value' => serialize( $value ) );
 763                 if ( count( $this->batch ) >= 100 ) {
 764                         $this->dbw->insert( 'l10n_cache', $this->batch, __METHOD__ );
 765                         $this->batch = array();
 766                 }
 767         }
 768 }
 769
 770 /**
 771  * LCStore implementation which stores data as a collection of CDB files in the
 772  * directory given by $wgCacheDirectory. If $wgCacheDirectory is not set, this
 773  * will throw an exception.
 774  *
 775  * Profiling indicates that on Linux, this implementation outperforms MySQL if
 776  * the directory is on a local filesystem and there is ample kernel cache
 777  * space. The performance advantage is greater when the DBA extension is
 778  * available than it is with the PHP port.
 779  *
 780  * See Cdb.php and http://cr.yp.to/cdb.html
 781  */
 782 class LCStore_CDB implements LCStore {
 783         var $readers, $writer, $currentLang, $directory;
 784
 785         function __construct( $conf = array() ) {
 786                 global $wgCacheDirectory;
 787                 if ( isset( $conf['directory'] ) ) {
 788                         $this->directory = $conf['directory'];
 789                 } else {
 790                         $this->directory = $wgCacheDirectory;
 791                 }
 792         }
 793
 794         public function get( $code, $key ) {
 795                 if ( !isset( $this->readers[$code] ) ) {
 796                         $fileName = $this->getFileName( $code );
 797                         if ( !file_exists( $fileName ) ) {
 798                                 $this->readers[$code] = false;
 799                         } else {
 800                                 $this->readers[$code] = CdbReader::open( $fileName );
 801                         }
 802                 }
 803                 if ( !$this->readers[$code] ) {
 804                         return null;
 805                 } else {
 806                         $value = $this->readers[$code]->get( $key );
 807                         if ( $value === false ) {
 808                                 return null;
 809                         }
 810                         return unserialize( $value );
 811                 }
 812         }
 813
 814         public function startWrite( $code ) {
 815                 if ( !file_exists( $this->directory ) ) {
 816                         if ( !wfMkdirParents( $this->directory ) ) {
 817                                 throw new MWException( "Unable to create the localisation store " .
 818                                         "directory \"{$this->directory}\"" );
 819                         }
 820                 }
 821                 $this->writer = CdbWriter::open( $this->getFileName( $code ) );
 822                 $this->currentLang = $code;
 823         }
 824
 825         public function finishWrite() {
 826                 // Close the writer
 827                 $this->writer->close();
 828                 $this->writer = null;
 829
 830                 // Reopen the reader
 831                 if ( !empty( $this->readers[$this->currentLang] ) ) {
 832                         $this->readers[$this->currentLang]->close();
 833                 }
 834                 unset( $this->readers[$this->currentLang] );
 835                 $this->currentLang = null;
 836         }
 837
 838         public function set( $key, $value ) {
 839                 if ( is_null( $this->writer ) ) {
 840                         throw new MWException( __CLASS__.': must call startWrite() before calling set()' );
 841                 }
 842                 $this->writer->set( $key, serialize( $value ) );
 843         }
 844
 845         protected function getFileName( $code ) {
 846                 if ( !$code || strpos( $code, '/' ) !== false ) {
 847                         throw new MWException( __METHOD__.": Invalid language \"$code\"" );
 848                 }
 849                 return "{$this->directory}/l10n_cache-$code.cdb";
 850         }
 851 }
 852
 853 /**
 854  * Null store backend, used to avoid DB errors during install
 855  */
 856 class LCStore_Null implements LCStore {
 857         public function get( $code, $key ) {
 858                 return null;
 859         }
 860
 861         public function startWrite( $code ) {}
 862         public function finishWrite() {}
 863         public function set( $key, $value ) {}
 864 }
 865
 866 /**
 867  * A localisation cache optimised for loading large amounts of data for many
 868  * languages. Used by rebuildLocalisationCache.php.
 869  */
 870 class LocalisationCache_BulkLoad extends LocalisationCache {
 871         /**
 872          * A cache of the contents of data files.
 873          * Core files are serialized to avoid using ~1GB of RAM during a recache.
 874          */
 875         var $fileCache = array();
 876
 877         /**
 878          * Most recently used languages. Uses the linked-list aspect of PHP hashtables
 879          * to keep the most recently used language codes at the end of the array, and
 880          * the language codes that are ready to be deleted at the beginning.
 881          */
 882         var $mruLangs = array();
 883
 884         /**
 885          * Maximum number of languages that may be loaded into $this->data
 886          */
 887         var $maxLoadedLangs = 10;
 888
 889         protected function readPHPFile( $fileName, $fileType ) {
 890                 $serialize = $fileType === 'core';
 891                 if ( !isset( $this->fileCache[$fileName][$fileType] ) ) {
 892                         $data = parent::readPHPFile( $fileName, $fileType );
 893                         if ( $serialize ) {
 894                                 $encData = serialize( $data );
 895                         } else {
 896                                 $encData = $data;
 897                         }
 898                         $this->fileCache[$fileName][$fileType] = $encData;
 899                         return $data;
 900                 } elseif ( $serialize ) {
 901                         return unserialize( $this->fileCache[$fileName][$fileType] );
 902                 } else {
 903                         return $this->fileCache[$fileName][$fileType];
 904                 }
 905         }
 906
 907         public function getItem( $code, $key ) {
 908                 unset( $this->mruLangs[$code] );
 909                 $this->mruLangs[$code] = true;
 910                 return parent::getItem( $code, $key );
 911         }
 912
 913         public function getSubitem( $code, $key, $subkey ) {
 914                 unset( $this->mruLangs[$code] );
 915                 $this->mruLangs[$code] = true;
 916                 return parent::getSubitem( $code, $key, $subkey );
 917         }
 918
 919         public function recache( $code ) {
 920                 parent::recache( $code );
 921                 unset( $this->mruLangs[$code] );
 922                 $this->mruLangs[$code] = true;
 923                 $this->trimCache();
 924         }
 925
 926         public function unload( $code ) {
 927                 unset( $this->mruLangs[$code] );
 928                 parent::unload( $code );
 929         }
 930
 931         /**
 932          * Unload cached languages until there are less than $this->maxLoadedLangs
 933          */
 934         protected function trimCache() {
 935                 while ( count( $this->data ) > $this->maxLoadedLangs && count( $this->mruLangs ) ) {
 936                         reset( $this->mruLangs );
 937                         $code = key( $this->mruLangs );
 938                         wfDebug( __METHOD__.": unloading $code\n" );
 939                         $this->unload( $code );
 940                 }
 941         }
 942 }