includes/MessageCache.php

   1 <?php
   2 /**
   3  * @file
   4  * @ingroup Cache
   5  */
   6
   7 /**
   8  *
   9  */
  10 define( 'MSG_LOAD_TIMEOUT', 60);
  11 define( 'MSG_LOCK_TIMEOUT', 10);
  12 define( 'MSG_WAIT_TIMEOUT', 10);
  13 define( 'MSG_CACHE_VERSION', 1 );
  14
  15 /**
  16  * Message cache
  17  * Performs various MediaWiki namespace-related functions
  18  * @ingroup Cache
  19  */
  20 class MessageCache {
  21         // Holds loaded messages that are defined in MediaWiki namespace.
  22         var $mCache;
  23
  24         var $mUseCache, $mDisable, $mExpiry;
  25         var $mKeys, $mParserOptions, $mParser;
  26         var $mExtensionMessages = array();
  27         var $mInitialised = false;
  28         var $mAllMessagesLoaded; // Extension messages
  29
  30         // Variable for tracking which variables are loaded
  31         var $mLoadedLanguages = array();
  32
  33         function __construct( &$memCached, $useDB, $expiry, /*ignored*/ $memcPrefix ) {
  34                 $this->mUseCache = !is_null( $memCached );
  35                 $this->mMemc = &$memCached;
  36                 $this->mDisable = !$useDB;
  37                 $this->mExpiry = $expiry;
  38                 $this->mDisableTransform = false;
  39                 $this->mKeys = false; # initialised on demand
  40                 $this->mInitialised = true;
  41                 $this->mParser = null;
  42         }
  43
  44
  45         /**
  46          * ParserOptions is lazy initialised.
  47          * Access should probably be protected.
  48          */
  49         function getParserOptions() {
  50                 if ( !$this->mParserOptions ) {
  51                         $this->mParserOptions = new ParserOptions;
  52                 }
  53                 return $this->mParserOptions;
  54         }
  55
  56         /**
  57          * Try to load the cache from a local file.
  58          * Actual format of the file depends on the $wgLocalMessageCacheSerialized
  59          * setting.
  60          *
  61          * @param $hash String: the hash of contents, to check validity.
  62          * @param $code Mixed: Optional language code, see documenation of load().
  63          * @return false on failure.
  64          */
  65         function loadFromLocal( $hash, $code ) {
  66                 global $wgLocalMessageCache, $wgLocalMessageCacheSerialized;
  67
  68                 $filename = "$wgLocalMessageCache/messages-" . wfWikiID() . "-$code";
  69
  70                 # Check file existence
  71                 wfSuppressWarnings();
  72                 $file = fopen( $filename, 'r' );
  73                 wfRestoreWarnings();
  74                 if ( !$file ) {
  75                         return false; // No cache file
  76                 }
  77
  78                 if ( $wgLocalMessageCacheSerialized ) {
  79                         // Check to see if the file has the hash specified
  80                         $localHash = fread( $file, 32 );
  81                         if ( $hash === $localHash ) {
  82                                 // All good, get the rest of it
  83                                 $serialized = '';
  84                                 while ( !feof( $file ) ) {
  85                                         $serialized .= fread( $file, 100000 );
  86                                 }
  87                                 fclose( $file );
  88                                 return $this->setCache( unserialize( $serialized ), $code );
  89                         } else {
  90                                 fclose( $file );
  91                                 return false; // Wrong hash
  92                         }
  93                 } else {
  94                         $localHash=substr(fread($file,40),8);
  95                         fclose($file);
  96                         if ($hash!=$localHash) {
  97                                 return false; // Wrong hash
  98                         }
  99
 100                         # Require overwrites the member variable or just shadows it?
 101                         require( $filename );
 102                         return $this->setCache( $this->mCache, $code );
 103                 }
 104         }
 105
 106         /**
 107          * Save the cache to a local file.
 108          */
 109         function saveToLocal( $serialized, $hash, $code ) {
 110                 global $wgLocalMessageCache;
 111
 112                 $filename = "$wgLocalMessageCache/messages-" . wfWikiID() . "-$code";
 113                 wfMkdirParents( $wgLocalMessageCache, 0777 ); // might fail
 114
 115                 wfSuppressWarnings();
 116                 $file = fopen( $filename, 'w' );
 117                 wfRestoreWarnings();
 118
 119                 if ( !$file ) {
 120                         wfDebug( "Unable to open local cache file for writing\n" );
 121                         return;
 122                 }
 123
 124                 fwrite( $file, $hash . $serialized );
 125                 fclose( $file );
 126                 @chmod( $filename, 0666 );
 127         }
 128
 129         function saveToScript( $array, $hash, $code ) {
 130                 global $wgLocalMessageCache;
 131
 132                 $filename = "$wgLocalMessageCache/messages-" . wfWikiID() . "-$code";
 133                 $tempFilename = $filename . '.tmp';
 134         wfMkdirParents( $wgLocalMessageCache, 0777 ); // might fail
 135
 136                 wfSuppressWarnings();
 137                 $file = fopen( $tempFilename, 'w');
 138                 wfRestoreWarnings();
 139
 140                 if ( !$file ) {
 141                         wfDebug( "Unable to open local cache file for writing\n" );
 142                         return;
 143                 }
 144
 145                 fwrite($file,"<?php\n//$hash\n\n \$this->mCache = array(");
 146
 147                 foreach ($array as $key => $message) {
 148                         $key = $this->escapeForScript($key);
 149                         $messages = $this->escapeForScript($message);
 150                         fwrite($file, "'$key' => '$message',\n");
 151                 }
 152
 153                 fwrite($file,");\n?>");
 154                 fclose($file);
 155                 rename($tempFilename, $filename);
 156         }
 157
 158         function escapeForScript($string) {
 159                 $string = str_replace( '\\', '\\\\', $string );
 160                 $string = str_replace( '\'', '\\\'', $string );
 161                 return $string;
 162         }
 163
 164         /**
 165          * Set the cache to $cache, if it is valid. Otherwise set the cache to false.
 166          */
 167         function setCache( $cache, $code ) {
 168                 if ( isset( $cache['VERSION'] ) && $cache['VERSION'] == MSG_CACHE_VERSION ) {
 169                         $this->mCache[$code] = $cache;
 170                         return true;
 171                 } else {
 172                         return false;
 173                 }
 174         }
 175
 176         /**
 177          * Loads messages from caches or from database in this order:
 178          * (1) local message cache (if $wgLocalMessageCache is enabled)
 179          * (2) memcached
 180          * (3) from the database.
 181          *
 182          * When succesfully loading from (2) or (3), all higher level caches are
 183          * updated for the newest version.
 184          *
 185          * Nothing is loaded if  member variable mDisabled is true, either manually
 186          * set by calling code or if message loading fails (is this possible?).
 187          *
 188          * Returns true if cache is already populated or it was succesfully populated,
 189          * or false if populating empty cache fails. Also returns true if MessageCache
 190          * is disabled.
 191          *
 192          * @param $code String: language to which load messages
 193          */
 194         function load( $code = false ) {
 195                 global $wgLocalMessageCache;
 196
 197                 if ( !$this->mUseCache ) {
 198                         return true;
 199                 }
 200
 201                 if( !is_string( $code ) ) {
 202                         # This isn't really nice, so at least make a note about it and try to
 203                         # fall back
 204                         wfDebug( __METHOD__ . " called without providing a language code\n" );
 205                         $code = 'en';
 206                 }
 207
 208                 # Don't do double loading...
 209                 if ( isset($this->mLoadedLanguages[$code]) ) return true;
 210
 211                 # 8 lines of code just to say (once) that message cache is disabled
 212                 if ( $this->mDisable ) {
 213                         static $shownDisabled = false;
 214                         if ( !$shownDisabled ) {
 215                                 wfDebug( __METHOD__ . ": disabled\n" );
 216                                 $shownDisabled = true;
 217                         }
 218                         return true;
 219                 }
 220
 221                 # Loading code starts
 222                 wfProfileIn( __METHOD__ );
 223                 $success = false; # Keep track of success
 224                 $where = array(); # Debug info, delayed to avoid spamming debug log too much
 225                 $cacheKey = wfMemcKey( 'messages', $code ); # Key in memc for messages
 226
 227
 228                 # (1) local cache
 229                 # Hash of the contents is stored in memcache, to detect if local cache goes
 230                 # out of date (due to update in other thread?)
 231                 if ( $wgLocalMessageCache !== false ) {
 232                         wfProfileIn( __METHOD__ . '-fromlocal' );
 233
 234                         $hash = $this->mMemc->get( wfMemcKey( 'messages', $code, 'hash' ) );
 235                         if ( $hash ) {
 236                                 $success = $this->loadFromLocal( $hash, $code );
 237                                 if ( $success ) $where[] = 'got from local cache';
 238                         }
 239                         wfProfileOut( __METHOD__ . '-fromlocal' );
 240                 }
 241
 242                 # (2) memcache
 243                 # Fails if nothing in cache, or in the wrong version.
 244                 if ( !$success ) {
 245                         wfProfileIn( __METHOD__ . '-fromcache' );
 246                         $cache = $this->mMemc->get( $cacheKey );
 247                         $success = $this->setCache( $cache, $code );
 248                         if ( $success ) {
 249                                 $where[] = 'got from global cache';
 250                                 $this->saveToCaches( $cache, false, $code );
 251                         }
 252                         wfProfileOut( __METHOD__ . '-fromcache' );
 253                 }
 254
 255
 256                 # (3)
 257                 # Nothing in caches... so we need create one and store it in caches
 258                 if ( !$success ) {
 259                         $where[] = 'cache is empty';
 260                         $where[] = 'loading from database';
 261
 262                         $this->lock($cacheKey);
 263
 264                         $cache = $this->loadFromDB( $code );
 265                         $success = $this->setCache( $cache, $code );
 266                         if ( $success ) {
 267                                 $this->saveToCaches( $cache, true, $code );
 268                         }
 269
 270                         $this->unlock($cacheKey);
 271                 }
 272
 273                 if ( !$success ) {
 274                         # Bad luck... this should not happen
 275                         $where[] = 'loading FAILED - cache is disabled';
 276                         $info = implode( ', ', $where );
 277                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 278                         $this->mDisable = true;
 279                         $this->mCache = false;
 280                 } else {
 281                         # All good, just record the success
 282                         $info = implode( ', ', $where );
 283                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 284                         $this->mLoadedLanguages[$code] = true;
 285                 }
 286                 wfProfileOut( __METHOD__ );
 287                 return $success;
 288         }
 289
 290         /**
 291          * Loads cacheable messages from the database. Messages bigger than
 292          * $wgMaxMsgCacheEntrySize are assigned a special value, and are loaded
 293          * on-demand from the database later.
 294          *
 295          * @param $code Optional language code, see documenation of load().
 296          * @return Array: Loaded messages for storing in caches.
 297          */
 298         function loadFromDB( $code = false ) {
 299                 wfProfileIn( __METHOD__ );
 300                 global $wgMaxMsgCacheEntrySize, $wgContLanguageCode;
 301                 $dbr = wfGetDB( DB_SLAVE );
 302                 $cache = array();
 303
 304                 # Common conditions
 305                 $conds = array(
 306                         'page_is_redirect' => 0,
 307                         'page_namespace' => NS_MEDIAWIKI,
 308                 );
 309
 310                 if ( $code ) {
 311                         # Is this fast enough. Should not matter if the filtering is done in the
 312                         # database or in code.
 313                         if ( $code !== $wgContLanguageCode ) {
 314                                 # Messages for particular language
 315                                 $escapedCode = $dbr->escapeLike( $code );
 316                                 $conds[] = "page_title like '%%/$escapedCode'";
 317                         } else {
 318                                 # Effectively disallows use of '/' character in NS_MEDIAWIKI for uses
 319                                 # other than language code.
 320                                 $conds[] = "page_title not like '%%/%%'";
 321                         }
 322                 }
 323
 324                 # Conditions to fetch oversized pages to ignore them
 325                 $bigConds = $conds;
 326                 $bigConds[] = 'page_len > ' . intval( $wgMaxMsgCacheEntrySize );
 327
 328                 # Load titles for all oversized pages in the MediaWiki namespace
 329                 $res = $dbr->select( 'page', 'page_title', $bigConds, __METHOD__ );
 330                 while ( $row = $dbr->fetchObject( $res ) ) {
 331                         $cache[$row->page_title] = '!TOO BIG';
 332                 }
 333                 $dbr->freeResult( $res );
 334
 335                 # Conditions to load the remaining pages with their contents
 336                 $smallConds = $conds;
 337                 $smallConds[] = 'page_latest=rev_id';
 338                 $smallConds[] = 'rev_text_id=old_id';
 339                 $smallConds[] = 'page_len <= ' . intval( $wgMaxMsgCacheEntrySize );
 340
 341                 $res = $dbr->select( array( 'page', 'revision', 'text' ),
 342                         array( 'page_title', 'old_text', 'old_flags' ),
 343                         $smallConds, __METHOD__ );
 344
 345                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 346                         $cache[$row->page_title] = ' ' . Revision::getRevisionText( $row );
 347                 }
 348                 $dbr->freeResult( $res );
 349
 350                 $cache['VERSION'] = MSG_CACHE_VERSION;
 351                 wfProfileOut( __METHOD__ );
 352                 return $cache;
 353         }
 354
 355         /**
 356          * Updates cache as necessary when message page is changed
 357          *
 358          * @param $title String: name of the page changed.
 359          * @param $text Mixed: new contents of the page.
 360          */
 361         public function replace( $title, $text ) {
 362                 global $wgMaxMsgCacheEntrySize;
 363                 wfProfileIn( __METHOD__ );
 364
 365
 366                 list( , $code ) = $this->figureMessage( $title );
 367
 368                 $cacheKey = wfMemcKey( 'messages', $code );
 369                 $this->load($code);
 370                 $this->lock($cacheKey);
 371
 372                 if ( is_array($this->mCache[$code]) ) {
 373                         $titleKey = wfMemcKey( 'messages', 'individual', $title );
 374
 375                         if ( $text === false ) {
 376                                 # Article was deleted
 377                                 unset( $this->mCache[$code][$title] );
 378                                 $this->mMemc->delete( $titleKey );
 379
 380                         } elseif ( strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
 381                                 # Check for size
 382                                 $this->mCache[$code][$title] = '!TOO BIG';
 383                                 $this->mMemc->set( $titleKey, ' ' . $text, $this->mExpiry );
 384
 385                         } else {
 386                                 $this->mCache[$code][$title] = ' ' . $text;
 387                                 $this->mMemc->delete( $titleKey );
 388                         }
 389
 390                         # Update caches
 391                         $this->saveToCaches( $this->mCache[$code], true, $code );
 392                 }
 393                 $this->unlock($cacheKey);
 394
 395                 // Also delete cached sidebar... just in case it is affected
 396                 global $parserMemc;
 397                 $sidebarKey = wfMemcKey( 'sidebar', $code );
 398                 $parserMemc->delete( $sidebarKey );
 399
 400                 wfProfileOut( __METHOD__ );
 401         }
 402
 403         /**
 404          * Shortcut to update caches.
 405          *
 406          * @param $cache Array: cached messages with a version.
 407          * @param $cacheKey String: Identifier for the cache.
 408          * @param $memc Bool: Wether to update or not memcache.
 409          * @param $code String: Language code.
 410          * @return False on somekind of error.
 411          */
 412         protected function saveToCaches( $cache, $memc = true, $code = false ) {
 413                 wfProfileIn( __METHOD__ );
 414                 global $wgLocalMessageCache, $wgLocalMessageCacheSerialized;
 415
 416                 $cacheKey = wfMemcKey( 'messages', $code );
 417                 $statusKey = wfMemcKey( 'messages', $code, 'status' );
 418
 419                 $success = $this->mMemc->add( $statusKey, 'loading', MSG_LOAD_TIMEOUT );
 420                 if ( !$success ) return true; # Other process should be updating them now
 421
 422                 $i = 0;
 423                 if ( $memc ) {
 424                         # Save in memcached
 425                         # Keep trying if it fails, this is kind of important
 426
 427                         for ($i=0; $i<20 &&
 428                                 !$this->mMemc->set( $cacheKey, $cache, $this->mExpiry );
 429                                 $i++ ) {
 430                                 usleep(mt_rand(500000,1500000));
 431                         }
 432                 }
 433
 434                 # Save to local cache
 435                 if ( $wgLocalMessageCache !== false ) {
 436                         $serialized = serialize( $cache );
 437                         $hash = md5( $serialized );
 438                         $this->mMemc->set( wfMemcKey( 'messages', $code, 'hash' ), $hash, $this->mExpiry );
 439                         if ($wgLocalMessageCacheSerialized) {
 440                                 $this->saveToLocal( $serialized, $hash, $code );
 441                         } else {
 442                                 $this->saveToScript( $cache, $hash, $code );
 443                         }
 444                 }
 445
 446                 if ( $i == 20 ) {
 447                         $this->mMemc->set( $statusKey, 'error', 60*5 );
 448                         wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 449                         $success = false;
 450                 } else {
 451                         $this->mMemc->delete( $statusKey );
 452                         $success = true;
 453                 }
 454                 wfProfileOut( __METHOD__ );
 455                 return $success;
 456         }
 457
 458         /**
 459          * Returns success
 460          * Represents a write lock on the messages key
 461          */
 462         function lock($key) {
 463                 if ( !$this->mUseCache ) {
 464                         return true;
 465                 }
 466
 467                 $lockKey = $key . ':lock';
 468                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 469                         sleep(1);
 470                 }
 471
 472                 return $i >= MSG_WAIT_TIMEOUT;
 473         }
 474
 475         function unlock($key) {
 476                 if ( !$this->mUseCache ) {
 477                         return;
 478                 }
 479
 480                 $lockKey = $key . ':lock';
 481                 $this->mMemc->delete( $lockKey );
 482         }
 483
 484         /**
 485          * Get a message from either the content language or the user language.
 486          *
 487          * @param string $key The message cache key
 488          * @param bool $useDB Get the message from the DB, false to use only the localisation
 489          * @param string $langcode Code of the language to get the message for, if
 490          *                         it is a valid code create a language for that
 491          *                         language, if it is a string but not a valid code
 492          *                         then make a basic language object, if it is a
 493          *                         false boolean then use the current users
 494          *                         language (as a fallback for the old parameter
 495          *                         functionality), or if it is a true boolean then
 496          *                         use the wikis content language (also as a
 497          *                         fallback).
 498          * @param bool $isFullKey Specifies whether $key is a two part key "lang/msg".
 499          */
 500         function get( $key, $useDB = true, $langcode = true, $isFullKey = false ) {
 501                 global $wgContLanguageCode, $wgContLang, $wgLang;
 502
 503                 # Identify which language to get or create a language object for.
 504                 if( $langcode === $wgContLang->getCode() || $langcode === true ) {
 505                         # $langcode is the language code of the wikis content language object.
 506                         # or it is a boolean and value is true
 507                         $lang =& $wgContLang;
 508                 } elseif( $langcode === $wgLang->getCode() || $langcode === false ) {
 509                         # $langcode is the language code of user language object.
 510                         # or it was a boolean and value is false
 511                         $lang =& $wgLang;
 512                 } else {
 513                         $validCodes = array_keys( Language::getLanguageNames() );
 514                         if( in_array( $langcode, $validCodes ) ) {
 515                                 # $langcode corresponds to a valid language.
 516                                 $lang = Language::factory( $langcode );
 517                         } else {
 518                                 # $langcode is a string, but not a valid language code; use content language.
 519                                 $lang =& $wgContLang;
 520                                 wfDebug( 'Invalid language code passed to MessageCache::get, falling back to content language.' );
 521                         }
 522                 }
 523
 524                 $langcode = $lang->getCode();
 525
 526                 # If uninitialised, someone is trying to call this halfway through Setup.php
 527                 if( !$this->mInitialised ) {
 528                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 529                 }
 530
 531                 $message = false;
 532
 533                 # Normalise title-case input
 534                 $lckey = $wgContLang->lcfirst( $key );
 535                 $lckey = str_replace( ' ', '_', $lckey );
 536
 537                 # Try the MediaWiki namespace
 538                 if( !$this->mDisable && $useDB ) {
 539                         $title = $wgContLang->ucfirst( $lckey );
 540                         if(!$isFullKey && ($langcode != $wgContLanguageCode) ) {
 541                                 $title .= '/' . $langcode;
 542                         }
 543                         $message = $this->getMsgFromNamespace( $title, $langcode );
 544                 }
 545
 546                 # Try the extension array
 547                 if ( $message === false && isset( $this->mExtensionMessages[$langcode][$lckey] ) ) {
 548                         $message = $this->mExtensionMessages[$langcode][$lckey];
 549                 }
 550                 if ( $message === false && isset( $this->mExtensionMessages['en'][$lckey] ) ) {
 551                         $message = $this->mExtensionMessages['en'][$lckey];
 552                 }
 553
 554                 # Try the array in the language object
 555                 if ( $message === false ) {
 556                         $message = $lang->getMessage( $lckey );
 557                         if ( is_null( $message ) ) {
 558                                 $message = false;
 559                         }
 560                 }
 561
 562                 # Try the array of another language
 563                 $pos = strrpos( $lckey, '/' );
 564                 if( $message === false && $pos !== false) {
 565                         $mkey = substr( $lckey, 0, $pos );
 566                         $code = substr( $lckey, $pos+1 );
 567                         if ( $code ) {
 568                                 # We may get calls for things that are http-urls from sidebar
 569                                 # Let's not load nonexistent languages for those
 570                                 $validCodes = array_keys( Language::getLanguageNames() );
 571                                 if ( in_array( $code, $validCodes ) ) {
 572                                         $message = Language::getMessageFor( $mkey, $code );
 573                                         if ( is_null( $message ) ) {
 574                                                 $message = false;
 575                                         }
 576                                 }
 577                         }
 578                 }
 579
 580                 # Is this a custom message? Try the default language in the db...
 581                 if( ($message === false || $message === '-' ) &&
 582                         !$this->mDisable && $useDB &&
 583                         !$isFullKey && ($langcode != $wgContLanguageCode) ) {
 584                         $message = $this->getMsgFromNamespace( $wgContLang->ucfirst( $lckey ), $wgContLanguageCode );
 585                 }
 586
 587                 # Final fallback
 588                 if( $message === false ) {
 589                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 590                 }
 591                 return $message;
 592         }
 593
 594         /**
 595          * Get a message from the MediaWiki namespace, with caching. The key must
 596          * first be converted to two-part lang/msg form if necessary.
 597          *
 598          * @param $title String: Message cache key with initial uppercase letter.
 599          * @param $code String: code denoting the language to try.
 600          */
 601         function getMsgFromNamespace( $title, $code ) {
 602                 $type = false;
 603                 $message = false;
 604
 605                 if ( $this->mUseCache ) {
 606                         $this->load( $code );
 607                         if (isset( $this->mCache[$code][$title] ) ) {
 608                                 $entry = $this->mCache[$code][$title];
 609                                 $type = substr( $entry, 0, 1 );
 610                                 if ( $type == ' ' ) {
 611                                         return substr( $entry, 1 );
 612                                 }
 613                         }
 614                 }
 615
 616                 # Call message hooks, in case they are defined
 617                 wfRunHooks('MessagesPreLoad', array( $title, &$message ) );
 618                 if ( $message !== false ) {
 619                         return $message;
 620                 }
 621
 622                 # If there is no cache entry and no placeholder, it doesn't exist
 623                 if ( $type !== '!' ) {
 624                         return false;
 625                 }
 626
 627                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 628
 629                 # Try the individual message cache
 630                 if ( $this->mUseCache ) {
 631                         $entry = $this->mMemc->get( $titleKey );
 632                         if ( $entry ) {
 633                                 $type = substr( $entry, 0, 1 );
 634
 635                                 if ( $type === ' ' ) {
 636                                         # Ok!
 637                                         $message = substr( $entry, 1 );
 638                                         $this->mCache[$code][$title] = $entry;
 639                                         return $message;
 640                                 } elseif ( $entry === '!NONEXISTENT' ) {
 641                                         return false;
 642                                 } else {
 643                                         # Corrupt/obsolete entry, delete it
 644                                         $this->mMemc->delete( $titleKey );
 645                                 }
 646
 647                         }
 648                 }
 649
 650                 # Try loading it from the DB
 651                 $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 652                 if( $revision ) {
 653                         $message = $revision->getText();
 654                         if ($this->mUseCache) {
 655                                 $this->mCache[$code][$title] = ' ' . $message;
 656                                 $this->mMemc->set( $titleKey, $message, $this->mExpiry );
 657                         }
 658                 } else {
 659                         # Negative caching
 660                         # Use some special text instead of false, because false gets converted to '' somewhere
 661                         $this->mMemc->set( $titleKey, '!NONEXISTENT', $this->mExpiry );
 662                         $this->mCache[$code][$title] = false;
 663                 }
 664                 return $message;
 665         }
 666
 667         function transform( $message, $interface = false ) {
 668                 // Avoid creating parser if nothing to transfrom
 669                 if( strpos( $message, '{{' ) === false ) {
 670                         return $message;
 671                 }
 672
 673                 global $wgParser;
 674                 if ( !$this->mParser && isset( $wgParser ) ) {
 675                         # Do some initialisation so that we don't have to do it twice
 676                         $wgParser->firstCallInit();
 677                         # Clone it and store it
 678                         $this->mParser = clone $wgParser;
 679                         #wfDebug( __METHOD__ . ": following contents triggered transform: $message\n" );
 680                 }
 681                 if ( $this->mParser ) {
 682                         $popts = $this->getParserOptions();
 683                         $popts->setInterfaceMessage( $interface );
 684                         $message = $this->mParser->transformMsg( $message, $popts );
 685                 }
 686                 return $message;
 687         }
 688
 689         function disable() { $this->mDisable = true; }
 690         function enable() { $this->mDisable = false; }
 691
 692         /** @deprecated */
 693         function disableTransform(){
 694                 wfDeprecated( __METHOD__ );
 695         }
 696         function enableTransform() {
 697                 wfDeprecated( __METHOD__ );
 698         }
 699         function setTransform( $x ) {
 700                 wfDeprecated( __METHOD__ );
 701         }
 702         function getTransform() {
 703                 wfDeprecated( __METHOD__ );
 704                 return false;
 705         }
 706
 707         /**
 708          * Add a message to the cache
 709          *
 710          * @param mixed $key
 711          * @param mixed $value
 712          * @param string $lang The messages language, English by default
 713          */
 714         function addMessage( $key, $value, $lang = 'en' ) {
 715                 $this->mExtensionMessages[$lang][$key] = $value;
 716         }
 717
 718         /**
 719          * Add an associative array of message to the cache
 720          *
 721          * @param array $messages An associative array of key => values to be added
 722          * @param string $lang The messages language, English by default
 723          */
 724         function addMessages( $messages, $lang = 'en' ) {
 725                 wfProfileIn( __METHOD__ );
 726                 if ( !is_array( $messages ) ) {
 727                         throw new MWException( __METHOD__.': Invalid message array' );
 728                 }
 729                 if ( isset( $this->mExtensionMessages[$lang] ) ) {
 730                         $this->mExtensionMessages[$lang] = $messages + $this->mExtensionMessages[$lang];
 731                 } else {
 732                         $this->mExtensionMessages[$lang] = $messages;
 733                 }
 734                 wfProfileOut( __METHOD__ );
 735         }
 736
 737         /**
 738          * Add a 2-D array of messages by lang. Useful for extensions.
 739          *
 740          * @param array $messages The array to be added
 741          */
 742         function addMessagesByLang( $messages ) {
 743                 wfProfileIn( __METHOD__ );
 744                 foreach ( $messages as $key => $value ) {
 745                         $this->addMessages( $value, $key );
 746                 }
 747                 wfProfileOut( __METHOD__ );
 748         }
 749
 750         /**
 751          * Get the extension messages for a specific language. Only English, interface
 752          * and content language are guaranteed to be loaded.
 753          *
 754          * @param string $lang The messages language, English by default
 755          */
 756         function getExtensionMessagesFor( $lang = 'en' ) {
 757                 wfProfileIn( __METHOD__ );
 758                 $messages = array();
 759                 if ( isset( $this->mExtensionMessages[$lang] ) ) {
 760                         $messages = $this->mExtensionMessages[$lang];
 761                 }
 762                 if ( $lang != 'en' ) {
 763                         $messages = $messages + $this->mExtensionMessages['en'];
 764                 }
 765                 wfProfileOut( __METHOD__ );
 766                 return $messages;
 767         }
 768
 769         /**
 770          * Clear all stored messages. Mainly used after a mass rebuild.
 771          */
 772         function clear() {
 773                 if( $this->mUseCache ) {
 774                         $langs = Language::getLanguageNames( false );
 775                         foreach ( array_keys($langs) as $code ) {
 776                                 # Global cache
 777                                 $this->mMemc->delete( wfMemcKey( 'messages', $code ) );
 778                                 # Invalidate all local caches
 779                                 $this->mMemc->delete( wfMemcKey( 'messages', $code, 'hash' ) );
 780                         }
 781                 }
 782         }
 783
 784         function loadAllMessages() {
 785                 global $wgExtensionMessagesFiles;
 786                 if ( $this->mAllMessagesLoaded ) {
 787                         return;
 788                 }
 789                 $this->mAllMessagesLoaded = true;
 790
 791                 # Some extensions will load their messages when you load their class file
 792                 wfLoadAllExtensions();
 793                 # Others will respond to this hook
 794                 wfRunHooks( 'LoadAllMessages' );
 795                 # Some register their messages in $wgExtensionMessagesFiles
 796                 foreach ( $wgExtensionMessagesFiles as $name => $file ) {
 797                         wfLoadExtensionMessages( $name );
 798                 }
 799                 # Still others will respond to neither, they are EVIL. We sometimes need to know!
 800         }
 801
 802         /**
 803          * Load messages from a given file
 804          *
 805          * @param string $filename Filename of file to load.
 806          * @param string $langcode Language to load messages for, or false for
 807      *                         default behvaiour (en, content language and user
 808      *                         language).
 809          */
 810         function loadMessagesFile( $filename, $langcode = false ) {
 811                 global $wgLang, $wgContLang;
 812                 $messages = $magicWords = false;
 813                 require( $filename );
 814
 815                 $validCodes = Language::getLanguageNames();
 816                 if( is_string( $langcode ) && array_key_exists( $langcode, $validCodes ) ) {
 817                         # Load messages for given language code.
 818                         $this->processMessagesArray( $messages, $langcode );
 819                 } elseif( is_string( $langcode ) && !array_key_exists( $langcode, $validCodes ) ) {
 820                         wfDebug( "Invalid language '$langcode' code passed to MessageCache::loadMessagesFile()" );
 821                 } else {
 822                         # Load only languages that are usually used, and merge all
 823                         # fallbacks, except English.
 824                         $langs = array_unique( array( 'en', $wgContLang->getCode(), $wgLang->getCode() ) );
 825                         foreach( $langs as $code ) {
 826                                 $this->processMessagesArray( $messages, $code );
 827                         }
 828                 }
 829
 830                 if ( $magicWords !== false ) {
 831                         global $wgContLang;
 832                         $wgContLang->addMagicWordsByLang( $magicWords );
 833                 }
 834         }
 835
 836         /**
 837          * Process an array of messages, loading it into the message cache.
 838          *
 839          * @param array $messages Messages array.
 840          * @param string $langcode Language code to process.
 841          */
 842         function processMessagesArray( $messages, $langcode ) {
 843                 $fallbackCode = $langcode;
 844                 $mergedMessages = array();
 845                 do {
 846                         if ( isset($messages[$fallbackCode]) ) {
 847                                 $mergedMessages += $messages[$fallbackCode];
 848                         }
 849                         $fallbackCode = Language::getFallbackfor( $fallbackCode );
 850                 } while( $fallbackCode && $fallbackCode !== 'en' );
 851
 852                 if ( !empty($mergedMessages) )
 853                         $this->addMessages( $mergedMessages, $langcode );
 854         }
 855
 856         public function figureMessage( $key ) {
 857                 global $wgContLanguageCode;
 858                 $pieces = explode('/', $key, 2);
 859
 860                 $key = $pieces[0];
 861
 862                 # Language the user is translating to
 863                 $langCode = isset($pieces[1]) ? $pieces[1] : $wgContLanguageCode;
 864                 return array( $key, $langCode );
 865         }
 866
 867 }