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