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
  27         // Variable for tracking which variables are loaded
  28         var $mLoadedLanguages = array();
  29
  30         function __construct( &$memCached, $useDB, $expiry, /*ignored*/ $memcPrefix ) {
  31                 $this->mUseCache = !is_null( $memCached );
  32                 $this->mMemc = &$memCached;
  33                 $this->mDisable = !$useDB;
  34                 $this->mExpiry = $expiry;
  35                 $this->mDisableTransform = false;
  36                 $this->mKeys = false; # initialised on demand
  37                 $this->mParser = null;
  38         }
  39
  40
  41         /**
  42          * ParserOptions is lazy initialised.
  43          */
  44         function getParserOptions() {
  45                 if ( !$this->mParserOptions ) {
  46                         $this->mParserOptions = new ParserOptions;
  47                 }
  48                 return $this->mParserOptions;
  49         }
  50
  51         /**
  52          * Try to load the cache from a local file.
  53          * Actual format of the file depends on the $wgLocalMessageCacheSerialized
  54          * setting.
  55          *
  56          * @param $hash String: the hash of contents, to check validity.
  57          * @param $code Mixed: Optional language code, see documenation of load().
  58          * @return false on failure.
  59          */
  60         function loadFromLocal( $hash, $code ) {
  61                 global $wgCacheDirectory, $wgLocalMessageCacheSerialized;
  62
  63                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
  64
  65                 # Check file existence
  66                 wfSuppressWarnings();
  67                 $file = fopen( $filename, 'r' );
  68                 wfRestoreWarnings();
  69                 if ( !$file ) {
  70                         return false; // No cache file
  71                 }
  72
  73                 if ( $wgLocalMessageCacheSerialized ) {
  74                         // Check to see if the file has the hash specified
  75                         $localHash = fread( $file, 32 );
  76                         if ( $hash === $localHash ) {
  77                                 // All good, get the rest of it
  78                                 $serialized = '';
  79                                 while ( !feof( $file ) ) {
  80                                         $serialized .= fread( $file, 100000 );
  81                                 }
  82                                 fclose( $file );
  83                                 return $this->setCache( unserialize( $serialized ), $code );
  84                         } else {
  85                                 fclose( $file );
  86                                 return false; // Wrong hash
  87                         }
  88                 } else {
  89                         $localHash=substr(fread($file,40),8);
  90                         fclose($file);
  91                         if ($hash!=$localHash) {
  92                                 return false; // Wrong hash
  93                         }
  94
  95                         # Require overwrites the member variable or just shadows it?
  96                         require( $filename );
  97                         return $this->setCache( $this->mCache, $code );
  98                 }
  99         }
 100
 101         /**
 102          * Save the cache to a local file.
 103          */
 104         function saveToLocal( $serialized, $hash, $code ) {
 105                 global $wgCacheDirectory;
 106
 107                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 108                 wfMkdirParents( $wgCacheDirectory ); // might fail
 109
 110                 wfSuppressWarnings();
 111                 $file = fopen( $filename, 'w' );
 112                 wfRestoreWarnings();
 113
 114                 if ( !$file ) {
 115                         wfDebug( "Unable to open local cache file for writing\n" );
 116                         return;
 117                 }
 118
 119                 fwrite( $file, $hash . $serialized );
 120                 fclose( $file );
 121                 @chmod( $filename, 0666 );
 122         }
 123
 124         function saveToScript( $array, $hash, $code ) {
 125                 global $wgCacheDirectory;
 126
 127                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 128                 $tempFilename = $filename . '.tmp';
 129                 wfMkdirParents( $wgCacheDirectory ); // might fail
 130
 131                 wfSuppressWarnings();
 132                 $file = fopen( $tempFilename, 'w');
 133                 wfRestoreWarnings();
 134
 135                 if ( !$file ) {
 136                         wfDebug( "Unable to open local cache file for writing\n" );
 137                         return;
 138                 }
 139
 140                 fwrite($file,"<?php\n//$hash\n\n \$this->mCache = array(");
 141
 142                 foreach ($array as $key => $message) {
 143                         $key = $this->escapeForScript($key);
 144                         $messages = $this->escapeForScript($message);
 145                         fwrite($file, "'$key' => '$message',\n");
 146                 }
 147
 148                 fwrite($file,");\n?>");
 149                 fclose($file);
 150                 rename($tempFilename, $filename);
 151         }
 152
 153         function escapeForScript($string) {
 154                 $string = str_replace( '\\', '\\\\', $string );
 155                 $string = str_replace( '\'', '\\\'', $string );
 156                 return $string;
 157         }
 158
 159         /**
 160          * Set the cache to $cache, if it is valid. Otherwise set the cache to false.
 161          */
 162         function setCache( $cache, $code ) {
 163                 if ( isset( $cache['VERSION'] ) && $cache['VERSION'] == MSG_CACHE_VERSION ) {
 164                         $this->mCache[$code] = $cache;
 165                         return true;
 166                 } else {
 167                         return false;
 168                 }
 169         }
 170
 171         /**
 172          * Loads messages from caches or from database in this order:
 173          * (1) local message cache (if $wgUseLocalMessageCache is enabled)
 174          * (2) memcached
 175          * (3) from the database.
 176          *
 177          * When succesfully loading from (2) or (3), all higher level caches are
 178          * updated for the newest version.
 179          *
 180          * Nothing is loaded if  member variable mDisabled is true, either manually
 181          * set by calling code or if message loading fails (is this possible?).
 182          *
 183          * Returns true if cache is already populated or it was succesfully populated,
 184          * or false if populating empty cache fails. Also returns true if MessageCache
 185          * is disabled.
 186          *
 187          * @param $code String: language to which load messages
 188          */
 189         function load( $code = false ) {
 190                 global $wgUseLocalMessageCache;
 191
 192                 if ( !$this->mUseCache ) {
 193                         return true;
 194                 }
 195
 196                 if( !is_string( $code ) ) {
 197                         # This isn't really nice, so at least make a note about it and try to
 198                         # fall back
 199                         wfDebug( __METHOD__ . " called without providing a language code\n" );
 200                         $code = 'en';
 201                 }
 202
 203                 # Don't do double loading...
 204                 if ( isset($this->mLoadedLanguages[$code]) ) return true;
 205
 206                 # 8 lines of code just to say (once) that message cache is disabled
 207                 if ( $this->mDisable ) {
 208                         static $shownDisabled = false;
 209                         if ( !$shownDisabled ) {
 210                                 wfDebug( __METHOD__ . ": disabled\n" );
 211                                 $shownDisabled = true;
 212                         }
 213                         return true;
 214                 }
 215
 216                 # Loading code starts
 217                 wfProfileIn( __METHOD__ );
 218                 $success = false; # Keep track of success
 219                 $where = array(); # Debug info, delayed to avoid spamming debug log too much
 220                 $cacheKey = wfMemcKey( 'messages', $code ); # Key in memc for messages
 221
 222
 223                 # (1) local cache
 224                 # Hash of the contents is stored in memcache, to detect if local cache goes
 225                 # out of date (due to update in other thread?)
 226                 if ( $wgUseLocalMessageCache ) {
 227                         wfProfileIn( __METHOD__ . '-fromlocal' );
 228
 229                         $hash = $this->mMemc->get( wfMemcKey( 'messages', $code, 'hash' ) );
 230                         if ( $hash ) {
 231                                 $success = $this->loadFromLocal( $hash, $code );
 232                                 if ( $success ) $where[] = 'got from local cache';
 233                         }
 234                         wfProfileOut( __METHOD__ . '-fromlocal' );
 235                 }
 236
 237                 # (2) memcache
 238                 # Fails if nothing in cache, or in the wrong version.
 239                 if ( !$success ) {
 240                         wfProfileIn( __METHOD__ . '-fromcache' );
 241                         $cache = $this->mMemc->get( $cacheKey );
 242                         $success = $this->setCache( $cache, $code );
 243                         if ( $success ) {
 244                                 $where[] = 'got from global cache';
 245                                 $this->saveToCaches( $cache, false, $code );
 246                         }
 247                         wfProfileOut( __METHOD__ . '-fromcache' );
 248                 }
 249
 250
 251                 # (3)
 252                 # Nothing in caches... so we need create one and store it in caches
 253                 if ( !$success ) {
 254                         $where[] = 'cache is empty';
 255                         $where[] = 'loading from database';
 256
 257                         $this->lock($cacheKey);
 258
 259                         # Limit the concurrency of loadFromDB to a single process
 260                         # This prevents the site from going down when the cache expires
 261                         $statusKey = wfMemcKey( 'messages', $code, 'status' );
 262                         $success = $this->mMemc->add( $statusKey, 'loading', MSG_LOAD_TIMEOUT );
 263                         if ( $success ) {
 264                                 $cache = $this->loadFromDB( $code );
 265                                 $success = $this->setCache( $cache, $code );
 266                         }
 267                         if ( $success ) {
 268                                 $success = $this->saveToCaches( $cache, true, $code );
 269                                 if ( $success ) {
 270                                         $this->mMemc->delete( $statusKey );
 271                                 } else {
 272                                         $this->mMemc->set( $statusKey, 'error', 60*5 );
 273                                         wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 274                                 }
 275                         }
 276                         $this->unlock($cacheKey);
 277                 }
 278
 279                 if ( !$success ) {
 280                         # Bad luck... this should not happen
 281                         $where[] = 'loading FAILED - cache is disabled';
 282                         $info = implode( ', ', $where );
 283                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 284                         $this->mDisable = true;
 285                         $this->mCache = false;
 286                 } else {
 287                         # All good, just record the success
 288                         $info = implode( ', ', $where );
 289                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 290                         $this->mLoadedLanguages[$code] = true;
 291                 }
 292                 wfProfileOut( __METHOD__ );
 293                 return $success;
 294         }
 295
 296         /**
 297          * Loads cacheable messages from the database. Messages bigger than
 298          * $wgMaxMsgCacheEntrySize are assigned a special value, and are loaded
 299          * on-demand from the database later.
 300          *
 301          * @param $code Optional language code, see documenation of load().
 302          * @return Array: Loaded messages for storing in caches.
 303          */
 304         function loadFromDB( $code = false ) {
 305                 wfProfileIn( __METHOD__ );
 306                 global $wgMaxMsgCacheEntrySize, $wgContLanguageCode;
 307                 $dbr = wfGetDB( DB_SLAVE );
 308                 $cache = array();
 309
 310                 # Common conditions
 311                 $conds = array(
 312                         'page_is_redirect' => 0,
 313                         'page_namespace' => NS_MEDIAWIKI,
 314                 );
 315
 316                 if ( $code ) {
 317                         # Is this fast enough. Should not matter if the filtering is done in the
 318                         # database or in code.
 319                         if ( $code !== $wgContLanguageCode ) {
 320                                 # Messages for particular language
 321                                 $conds[] = 'page_title' . $dbr->buildLike( $dbr->anyString(), "/$code" );
 322                         } else {
 323                                 # Effectively disallows use of '/' character in NS_MEDIAWIKI for uses
 324                                 # other than language code.
 325                                 $conds[] = 'page_title NOT' . $dbr->buildLike( $dbr->anyString(), '/', $dbr->anyString() );
 326                         }
 327                 }
 328
 329                 # Conditions to fetch oversized pages to ignore them
 330                 $bigConds = $conds;
 331                 $bigConds[] = 'page_len > ' . intval( $wgMaxMsgCacheEntrySize );
 332
 333                 # Load titles for all oversized pages in the MediaWiki namespace
 334                 $res = $dbr->select( 'page', 'page_title', $bigConds, __METHOD__ . "($code)-big" );
 335                 while ( $row = $dbr->fetchObject( $res ) ) {
 336                         $cache[$row->page_title] = '!TOO BIG';
 337                 }
 338                 $dbr->freeResult( $res );
 339
 340                 # Conditions to load the remaining pages with their contents
 341                 $smallConds = $conds;
 342                 $smallConds[] = 'page_latest=rev_id';
 343                 $smallConds[] = 'rev_text_id=old_id';
 344                 $smallConds[] = 'page_len <= ' . intval( $wgMaxMsgCacheEntrySize );
 345
 346                 $res = $dbr->select( array( 'page', 'revision', 'text' ),
 347                         array( 'page_title', 'old_text', 'old_flags' ),
 348                         $smallConds, __METHOD__ . "($code)-small" );
 349
 350                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 351                         $cache[$row->page_title] = ' ' . Revision::getRevisionText( $row );
 352                 }
 353                 $dbr->freeResult( $res );
 354
 355                 $cache['VERSION'] = MSG_CACHE_VERSION;
 356                 wfProfileOut( __METHOD__ );
 357                 return $cache;
 358         }
 359
 360         /**
 361          * Updates cache as necessary when message page is changed
 362          *
 363          * @param $title String: name of the page changed.
 364          * @param $text Mixed: new contents of the page.
 365          */
 366         public function replace( $title, $text ) {
 367                 global $wgMaxMsgCacheEntrySize;
 368                 wfProfileIn( __METHOD__ );
 369
 370
 371                 list( , $code ) = $this->figureMessage( $title );
 372
 373                 $cacheKey = wfMemcKey( 'messages', $code );
 374                 $this->load($code);
 375                 $this->lock($cacheKey);
 376
 377                 if ( is_array($this->mCache[$code]) ) {
 378                         $titleKey = wfMemcKey( 'messages', 'individual', $title );
 379
 380                         if ( $text === false ) {
 381                                 # Article was deleted
 382                                 unset( $this->mCache[$code][$title] );
 383                                 $this->mMemc->delete( $titleKey );
 384
 385                         } elseif ( strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
 386                                 # Check for size
 387                                 $this->mCache[$code][$title] = '!TOO BIG';
 388                                 $this->mMemc->set( $titleKey, ' ' . $text, $this->mExpiry );
 389
 390                         } else {
 391                                 $this->mCache[$code][$title] = ' ' . $text;
 392                                 $this->mMemc->delete( $titleKey );
 393                         }
 394
 395                         # Update caches
 396                         $this->saveToCaches( $this->mCache[$code], true, $code );
 397                 }
 398                 $this->unlock($cacheKey);
 399
 400                 // Also delete cached sidebar... just in case it is affected
 401                 global $parserMemc;
 402                 $codes = array( $code );
 403                 if ( $code === 'en'  ) {
 404                         // Delete all sidebars, like for example on action=purge on the
 405                         // sidebar messages
 406                         $codes = array_keys( Language::getLanguageNames() );
 407                 }
 408
 409                 foreach ( $codes as $code ) {
 410                         $sidebarKey = wfMemcKey( 'sidebar', $code );
 411                         $parserMemc->delete( $sidebarKey );
 412                 }
 413
 414                 wfRunHooks( "MessageCacheReplace", array( $title, $text ) );
 415
 416                 wfProfileOut( __METHOD__ );
 417         }
 418
 419         /**
 420          * Shortcut to update caches.
 421          *
 422          * @param $cache Array: cached messages with a version.
 423          * @param $memc Bool: Wether to update or not memcache.
 424          * @param $code String: Language code.
 425          * @return False on somekind of error.
 426          */
 427         protected function saveToCaches( $cache, $memc = true, $code = false ) {
 428                 wfProfileIn( __METHOD__ );
 429                 global $wgUseLocalMessageCache, $wgLocalMessageCacheSerialized;
 430
 431                 $cacheKey = wfMemcKey( 'messages', $code );
 432
 433                 if ( $memc ) {
 434                         $success = $this->mMemc->set( $cacheKey, $cache, $this->mExpiry );
 435                 } else {
 436                         $success = true;
 437                 }
 438
 439                 # Save to local cache
 440                 if ( $wgUseLocalMessageCache ) {
 441                         $serialized = serialize( $cache );
 442                         $hash = md5( $serialized );
 443                         $this->mMemc->set( wfMemcKey( 'messages', $code, 'hash' ), $hash, $this->mExpiry );
 444                         if ($wgLocalMessageCacheSerialized) {
 445                                 $this->saveToLocal( $serialized, $hash, $code );
 446                         } else {
 447                                 $this->saveToScript( $cache, $hash, $code );
 448                         }
 449                 }
 450
 451                 wfProfileOut( __METHOD__ );
 452                 return $success;
 453         }
 454
 455         /**
 456          * Represents a write lock on the messages key
 457          *
 458          * @return Boolean: success
 459          */
 460         function lock($key) {
 461                 if ( !$this->mUseCache ) {
 462                         return true;
 463                 }
 464
 465                 $lockKey = $key . ':lock';
 466                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 467                         sleep(1);
 468                 }
 469
 470                 return $i >= MSG_WAIT_TIMEOUT;
 471         }
 472
 473         function unlock($key) {
 474                 if ( !$this->mUseCache ) {
 475                         return;
 476                 }
 477
 478                 $lockKey = $key . ':lock';
 479                 $this->mMemc->delete( $lockKey );
 480         }
 481
 482         /**
 483          * Get a message from either the content language or the user language.
 484          *
 485          * @param $key String: the message cache key
 486          * @param $useDB Boolean: get the message from the DB, false to use only
 487          *               the localisation
 488          * @param $langcode String: code of the language to get the message for, if
 489          *                  it is a valid code create a language for that language,
 490          *                  if it is a string but not a valid code then make a basic
 491          *                  language object, if it is a false boolean then use the
 492          *                  current users language (as a fallback for the old
 493          *                  parameter functionality), or if it is a true boolean
 494          *                  then use the wikis content language (also as a
 495          *                  fallback).
 496          * @param $isFullKey Boolean: specifies whether $key is a two part key
 497          *                   "msg/lang".
 498          */
 499         function get( $key, $useDB = true, $langcode = true, $isFullKey = false ) {
 500                 global $wgContLanguageCode, $wgContLang;
 501
 502                 if ( !is_string( $key ) ) {
 503                         throw new MWException( "Non-string key given" );
 504                 }
 505
 506                 if ( strval( $key ) === '' ) {
 507                         # Shortcut: the empty key is always missing
 508                         return false;
 509                 }
 510
 511                 $lang = wfGetLangObj( $langcode );
 512                 $langcode = $lang->getCode();
 513
 514                 $message = false;
 515
 516                 # Normalise title-case input (with some inlining)
 517                 $lckey = str_replace( ' ', '_', $key );
 518                 if ( ord( $key ) < 128 ) {
 519                         $lckey[0] = strtolower( $lckey[0] );
 520                         $uckey = ucfirst( $lckey );
 521                 } else {
 522                         $lckey = $wgContLang->lcfirst( $lckey );
 523                         $uckey = $wgContLang->ucfirst( $lckey );
 524                 }
 525
 526                 # Try the MediaWiki namespace
 527                 if( !$this->mDisable && $useDB ) {
 528                         $title = $uckey;
 529                         if(!$isFullKey && ( $langcode != $wgContLanguageCode ) ) {
 530                                 $title .= '/' . $langcode;
 531                         }
 532                         $message = $this->getMsgFromNamespace( $title, $langcode );
 533                 }
 534
 535                 # Try the array in the language object
 536                 if ( $message === false ) {
 537                         $message = $lang->getMessage( $lckey );
 538                         if ( is_null( $message ) ) {
 539                                 $message = false;
 540                         }
 541                 }
 542
 543                 # Try the array of another language
 544                 if( $message === false ) {
 545                         $parts = explode( '/', $lckey );
 546                         # We may get calls for things that are http-urls from sidebar
 547                         # Let's not load nonexistent languages for those
 548                         # They usually have more than one slash.
 549                         if ( count( $parts ) == 2 && $parts[1] !== '' ) {
 550                                 $message = Language::getMessageFor( $parts[0], $parts[1] );
 551                                 if ( is_null( $message ) ) {
 552                                         $message = false;
 553                                 }
 554                         }
 555                 }
 556
 557                 # Is this a custom message? Try the default language in the db...
 558                 if( ($message === false || $message === '-' ) &&
 559                         !$this->mDisable && $useDB &&
 560                         !$isFullKey && ($langcode != $wgContLanguageCode) ) {
 561                         $message = $this->getMsgFromNamespace( $uckey, $wgContLanguageCode );
 562                 }
 563
 564                 # Final fallback
 565                 if( $message === false ) {
 566                         return false;
 567                 }
 568
 569                 # Fix whitespace
 570                 $message = strtr( $message,
 571                         array(
 572                                 # Fix for trailing whitespace, removed by textarea
 573                                 '&#32;' => ' ',
 574                                 # Fix for NBSP, converted to space by firefox
 575                                 '&nbsp;' => "\xc2\xa0",
 576                                 '&#160;' => "\xc2\xa0",
 577                         ) );
 578
 579                 return $message;
 580         }
 581
 582         /**
 583          * Get a message from the MediaWiki namespace, with caching. The key must
 584          * first be converted to two-part lang/msg form if necessary.
 585          *
 586          * @param $title String: Message cache key with initial uppercase letter.
 587          * @param $code String: code denoting the language to try.
 588          */
 589         function getMsgFromNamespace( $title, $code ) {
 590                 $type = false;
 591                 $message = false;
 592
 593                 if ( $this->mUseCache ) {
 594                         $this->load( $code );
 595                         if (isset( $this->mCache[$code][$title] ) ) {
 596                                 $entry = $this->mCache[$code][$title];
 597                                 $type = substr( $entry, 0, 1 );
 598                                 if ( $type == ' ' ) {
 599                                         return substr( $entry, 1 );
 600                                 }
 601                         }
 602                 }
 603
 604                 # Call message hooks, in case they are defined
 605                 wfRunHooks('MessagesPreLoad', array( $title, &$message ) );
 606                 if ( $message !== false ) {
 607                         return $message;
 608                 }
 609
 610                 # If there is no cache entry and no placeholder, it doesn't exist
 611                 if ( $type !== '!' ) {
 612                         return false;
 613                 }
 614
 615                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 616
 617                 # Try the individual message cache
 618                 if ( $this->mUseCache ) {
 619                         $entry = $this->mMemc->get( $titleKey );
 620                         if ( $entry ) {
 621                                 $type = substr( $entry, 0, 1 );
 622
 623                                 if ( $type === ' ' ) {
 624                                         # Ok!
 625                                         $message = substr( $entry, 1 );
 626                                         $this->mCache[$code][$title] = $entry;
 627                                         return $message;
 628                                 } elseif ( $entry === '!NONEXISTENT' ) {
 629                                         return false;
 630                                 } else {
 631                                         # Corrupt/obsolete entry, delete it
 632                                         $this->mMemc->delete( $titleKey );
 633                                 }
 634
 635                         }
 636                 }
 637
 638                 # Try loading it from the DB
 639                 $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 640                 if( $revision ) {
 641                         $message = $revision->getText();
 642                         if ($this->mUseCache) {
 643                                 $this->mCache[$code][$title] = ' ' . $message;
 644                                 $this->mMemc->set( $titleKey, ' ' . $message, $this->mExpiry );
 645                         }
 646                 } else {
 647                         # Negative caching
 648                         # Use some special text instead of false, because false gets converted to '' somewhere
 649                         $this->mMemc->set( $titleKey, '!NONEXISTENT', $this->mExpiry );
 650                         $this->mCache[$code][$title] = false;
 651                 }
 652                 return $message;
 653         }
 654
 655         function transform( $message, $interface = false, $language = null ) {
 656                 // Avoid creating parser if nothing to transform
 657                 if( strpos( $message, '{{' ) === false ) {
 658                         return $message;
 659                 }
 660
 661                 global $wgParser, $wgParserConf;
 662                 if ( !$this->mParser && isset( $wgParser ) ) {
 663                         # Do some initialisation so that we don't have to do it twice
 664                         $wgParser->firstCallInit();
 665                         # Clone it and store it
 666                         $class = $wgParserConf['class'];
 667                         if ( $class == 'Parser_DiffTest' ) {
 668                                 # Uncloneable
 669                                 $this->mParser = new $class( $wgParserConf );
 670                         } else {
 671                                 $this->mParser = clone $wgParser;
 672                         }
 673                         #wfDebug( __METHOD__ . ": following contents triggered transform: $message\n" );
 674                 }
 675                 if ( $this->mParser ) {
 676                         $popts = $this->getParserOptions();
 677                         $popts->setInterfaceMessage( $interface );
 678                         $popts->setTargetLanguage( $language );
 679                         $message = $this->mParser->transformMsg( $message, $popts );
 680                 }
 681                 return $message;
 682         }
 683
 684         function disable() { $this->mDisable = true; }
 685         function enable() { $this->mDisable = false; }
 686
 687         /** @deprecated */
 688         function disableTransform(){
 689                 wfDeprecated( __METHOD__ );
 690         }
 691         function enableTransform() {
 692                 wfDeprecated( __METHOD__ );
 693         }
 694         function setTransform( $x ) {
 695                 wfDeprecated( __METHOD__ );
 696         }
 697         function getTransform() {
 698                 wfDeprecated( __METHOD__ );
 699                 return false;
 700         }
 701
 702         /**
 703          * Clear all stored messages. Mainly used after a mass rebuild.
 704          */
 705         function clear() {
 706                 if( $this->mUseCache ) {
 707                         $langs = Language::getLanguageNames( false );
 708                         foreach ( array_keys($langs) as $code ) {
 709                                 # Global cache
 710                                 $this->mMemc->delete( wfMemcKey( 'messages', $code ) );
 711                                 # Invalidate all local caches
 712                                 $this->mMemc->delete( wfMemcKey( 'messages', $code, 'hash' ) );
 713                         }
 714                 }
 715         }
 716
 717         /**
 718          * Add a message to the cache
 719          * @deprecated Use $wgExtensionMessagesFiles
 720          *
 721          * @param $key Mixed
 722          * @param $value Mixed
 723          * @param $lang String: the messages language, English by default
 724          */
 725         function addMessage( $key, $value, $lang = 'en' ) {
 726                 wfDeprecated( __METHOD__ );
 727                 $lc = Language::getLocalisationCache();
 728                 $lc->addLegacyMessages( array( $lang => array( $key => $value ) ) );
 729         }
 730
 731         /**
 732          * Add an associative array of message to the cache
 733          * @deprecated Use $wgExtensionMessagesFiles
 734          *
 735          * @param $messages Array: an associative array of key => values to be added
 736          * @param $lang String: the messages language, English by default
 737          */
 738         function addMessages( $messages, $lang = 'en' ) {
 739                 wfDeprecated( __METHOD__ );
 740                 $lc = Language::getLocalisationCache();
 741                 $lc->addLegacyMessages( array( $lang => $messages ) );
 742         }
 743
 744         /**
 745          * Add a 2-D array of messages by lang. Useful for extensions.
 746          * @deprecated Use $wgExtensionMessagesFiles
 747          *
 748          * @param $messages Array: the array to be added
 749          */
 750         function addMessagesByLang( $messages ) {
 751                 wfDeprecated( __METHOD__ );
 752                 $lc = Language::getLocalisationCache();
 753                 $lc->addLegacyMessages( $messages );
 754         }
 755
 756         /**
 757          * Set a hook for addMessagesByLang()
 758          */
 759         function setExtensionMessagesHook( $callback ) {
 760                 $this->mAddMessagesHook = $callback;
 761         }
 762
 763         /**
 764          * @deprecated
 765          */
 766         function loadAllMessages( $lang = false ) {
 767         }
 768
 769         /**
 770          * @deprecated
 771          */
 772         function loadMessagesFile( $filename, $langcode = false ) {
 773         }
 774
 775         public function figureMessage( $key ) {
 776                 global $wgContLanguageCode;
 777                 $pieces = explode( '/', $key );
 778                 if( count( $pieces ) < 2 )
 779                         return array( $key, $wgContLanguageCode );
 780
 781                 $lang = array_pop( $pieces );
 782                 $validCodes = Language::getLanguageNames();
 783                 if( !array_key_exists( $lang, $validCodes ) )
 784                         return array( $key, $wgContLanguageCode );
 785
 786                 $message = implode( '/', $pieces );
 787                 return array( $message, $lang );
 788         }
 789
 790 }