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 = array(); // 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                 $this->mParser = null;
  42         }
  43
  44
  45         /**
  46          * ParserOptions is lazy initialised.
  47          */
  48         function getParserOptions() {
  49                 if ( !$this->mParserOptions ) {
  50                         $this->mParserOptions = new ParserOptions;
  51                 }
  52                 return $this->mParserOptions;
  53         }
  54
  55         /**
  56          * Try to load the cache from a local file.
  57          * Actual format of the file depends on the $wgLocalMessageCacheSerialized
  58          * setting.
  59          *
  60          * @param $hash String: the hash of contents, to check validity.
  61          * @param $code Mixed: Optional language code, see documenation of load().
  62          * @return false on failure.
  63          */
  64         function loadFromLocal( $hash, $code ) {
  65                 global $wgLocalMessageCache, $wgLocalMessageCacheSerialized;
  66
  67                 $filename = "$wgLocalMessageCache/messages-" . wfWikiID() . "-$code";
  68
  69                 # Check file existence
  70                 wfSuppressWarnings();
  71                 $file = fopen( $filename, 'r' );
  72                 wfRestoreWarnings();
  73                 if ( !$file ) {
  74                         return false; // No cache file
  75                 }
  76
  77                 if ( $wgLocalMessageCacheSerialized ) {
  78                         // Check to see if the file has the hash specified
  79                         $localHash = fread( $file, 32 );
  80                         if ( $hash === $localHash ) {
  81                                 // All good, get the rest of it
  82                                 $serialized = '';
  83                                 while ( !feof( $file ) ) {
  84                                         $serialized .= fread( $file, 100000 );
  85                                 }
  86                                 fclose( $file );
  87                                 return $this->setCache( unserialize( $serialized ), $code );
  88                         } else {
  89                                 fclose( $file );
  90                                 return false; // Wrong hash
  91                         }
  92                 } else {
  93                         $localHash=substr(fread($file,40),8);
  94                         fclose($file);
  95                         if ($hash!=$localHash) {
  96                                 return false; // Wrong hash
  97                         }
  98
  99                         # Require overwrites the member variable or just shadows it?
 100                         require( $filename );
 101                         return $this->setCache( $this->mCache, $code );
 102                 }
 103         }
 104
 105         /**
 106          * Save the cache to a local file.
 107          */
 108         function saveToLocal( $serialized, $hash, $code ) {
 109                 global $wgLocalMessageCache;
 110
 111                 $filename = "$wgLocalMessageCache/messages-" . wfWikiID() . "-$code";
 112                 wfMkdirParents( $wgLocalMessageCache ); // might fail
 113
 114                 wfSuppressWarnings();
 115                 $file = fopen( $filename, 'w' );
 116                 wfRestoreWarnings();
 117
 118                 if ( !$file ) {
 119                         wfDebug( "Unable to open local cache file for writing\n" );
 120                         return;
 121                 }
 122
 123                 fwrite( $file, $hash . $serialized );
 124                 fclose( $file );
 125                 @chmod( $filename, 0666 );
 126         }
 127
 128         function saveToScript( $array, $hash, $code ) {
 129                 global $wgLocalMessageCache;
 130
 131                 $filename = "$wgLocalMessageCache/messages-" . wfWikiID() . "-$code";
 132                 $tempFilename = $filename . '.tmp';
 133                 wfMkdirParents( $wgLocalMessageCache ); // might fail
 134
 135                 wfSuppressWarnings();
 136                 $file = fopen( $tempFilename, 'w');
 137                 wfRestoreWarnings();
 138
 139                 if ( !$file ) {
 140                         wfDebug( "Unable to open local cache file for writing\n" );
 141                         return;
 142                 }
 143
 144                 fwrite($file,"<?php\n//$hash\n\n \$this->mCache = array(");
 145
 146                 foreach ($array as $key => $message) {
 147                         $key = $this->escapeForScript($key);
 148                         $messages = $this->escapeForScript($message);
 149                         fwrite($file, "'$key' => '$message',\n");
 150                 }
 151
 152                 fwrite($file,");\n?>");
 153                 fclose($file);
 154                 rename($tempFilename, $filename);
 155         }
 156
 157         function escapeForScript($string) {
 158                 $string = str_replace( '\\', '\\\\', $string );
 159                 $string = str_replace( '\'', '\\\'', $string );
 160                 return $string;
 161         }
 162
 163         /**
 164          * Set the cache to $cache, if it is valid. Otherwise set the cache to false.
 165          */
 166         function setCache( $cache, $code ) {
 167                 if ( isset( $cache['VERSION'] ) && $cache['VERSION'] == MSG_CACHE_VERSION ) {
 168                         $this->mCache[$code] = $cache;
 169                         return true;
 170                 } else {
 171                         return false;
 172                 }
 173         }
 174
 175         /**
 176          * Loads messages from caches or from database in this order:
 177          * (1) local message cache (if $wgLocalMessageCache is enabled)
 178          * (2) memcached
 179          * (3) from the database.
 180          *
 181          * When succesfully loading from (2) or (3), all higher level caches are
 182          * updated for the newest version.
 183          *
 184          * Nothing is loaded if  member variable mDisabled is true, either manually
 185          * set by calling code or if message loading fails (is this possible?).
 186          *
 187          * Returns true if cache is already populated or it was succesfully populated,
 188          * or false if populating empty cache fails. Also returns true if MessageCache
 189          * is disabled.
 190          *
 191          * @param $code String: language to which load messages
 192          */
 193         function load( $code = false ) {
 194                 global $wgLocalMessageCache;
 195
 196                 if ( !$this->mUseCache ) {
 197                         return true;
 198                 }
 199
 200                 if( !is_string( $code ) ) {
 201                         # This isn't really nice, so at least make a note about it and try to
 202                         # fall back
 203                         wfDebug( __METHOD__ . " called without providing a language code\n" );
 204                         $code = 'en';
 205                 }
 206
 207                 # Don't do double loading...
 208                 if ( isset($this->mLoadedLanguages[$code]) ) return true;
 209
 210                 # 8 lines of code just to say (once) that message cache is disabled
 211                 if ( $this->mDisable ) {
 212                         static $shownDisabled = false;
 213                         if ( !$shownDisabled ) {
 214                                 wfDebug( __METHOD__ . ": disabled\n" );
 215                                 $shownDisabled = true;
 216                         }
 217                         return true;
 218                 }
 219
 220                 # Loading code starts
 221                 wfProfileIn( __METHOD__ );
 222                 $success = false; # Keep track of success
 223                 $where = array(); # Debug info, delayed to avoid spamming debug log too much
 224                 $cacheKey = wfMemcKey( 'messages', $code ); # Key in memc for messages
 225
 226
 227                 # (1) local cache
 228                 # Hash of the contents is stored in memcache, to detect if local cache goes
 229                 # out of date (due to update in other thread?)
 230                 if ( $wgLocalMessageCache !== false ) {
 231                         wfProfileIn( __METHOD__ . '-fromlocal' );
 232
 233                         $hash = $this->mMemc->get( wfMemcKey( 'messages', $code, 'hash' ) );
 234                         if ( $hash ) {
 235                                 $success = $this->loadFromLocal( $hash, $code );
 236                                 if ( $success ) $where[] = 'got from local cache';
 237                         }
 238                         wfProfileOut( __METHOD__ . '-fromlocal' );
 239                 }
 240
 241                 # (2) memcache
 242                 # Fails if nothing in cache, or in the wrong version.
 243                 if ( !$success ) {
 244                         wfProfileIn( __METHOD__ . '-fromcache' );
 245                         $cache = $this->mMemc->get( $cacheKey );
 246                         $success = $this->setCache( $cache, $code );
 247                         if ( $success ) {
 248                                 $where[] = 'got from global cache';
 249                                 $this->saveToCaches( $cache, false, $code );
 250                         }
 251                         wfProfileOut( __METHOD__ . '-fromcache' );
 252                 }
 253
 254
 255                 # (3)
 256                 # Nothing in caches... so we need create one and store it in caches
 257                 if ( !$success ) {
 258                         $where[] = 'cache is empty';
 259                         $where[] = 'loading from database';
 260
 261                         $this->lock($cacheKey);
 262
 263                         # Limit the concurrency of loadFromDB to a single process
 264                         # This prevents the site from going down when the cache expires
 265                         $statusKey = wfMemcKey( 'messages', $code, 'status' );
 266                         $success = $this->mMemc->add( $statusKey, 'loading', MSG_LOAD_TIMEOUT );
 267                         if ( $success ) {
 268                                 $cache = $this->loadFromDB( $code );
 269                                 $success = $this->setCache( $cache, $code );
 270                         }
 271                         if ( $success ) {
 272                                 $success = $this->saveToCaches( $cache, true, $code );
 273                                 if ( $success ) {
 274                                         $this->mMemc->delete( $statusKey );
 275                                 } else {
 276                                         $this->mMemc->set( $statusKey, 'error', 60*5 );
 277                                         wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 278                                 }
 279                         }
 280                         $this->unlock($cacheKey);
 281                 }
 282
 283                 if ( !$success ) {
 284                         # Bad luck... this should not happen
 285                         $where[] = 'loading FAILED - cache is disabled';
 286                         $info = implode( ', ', $where );
 287                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 288                         $this->mDisable = true;
 289                         $this->mCache = false;
 290                 } else {
 291                         # All good, just record the success
 292                         $info = implode( ', ', $where );
 293                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 294                         $this->mLoadedLanguages[$code] = true;
 295                 }
 296                 wfProfileOut( __METHOD__ );
 297                 return $success;
 298         }
 299
 300         /**
 301          * Loads cacheable messages from the database. Messages bigger than
 302          * $wgMaxMsgCacheEntrySize are assigned a special value, and are loaded
 303          * on-demand from the database later.
 304          *
 305          * @param $code Optional language code, see documenation of load().
 306          * @return Array: Loaded messages for storing in caches.
 307          */
 308         function loadFromDB( $code = false ) {
 309                 wfProfileIn( __METHOD__ );
 310                 global $wgMaxMsgCacheEntrySize, $wgContLanguageCode;
 311                 $dbr = wfGetDB( DB_SLAVE );
 312                 $cache = array();
 313
 314                 # Common conditions
 315                 $conds = array(
 316                         'page_is_redirect' => 0,
 317                         'page_namespace' => NS_MEDIAWIKI,
 318                 );
 319
 320                 if ( $code ) {
 321                         # Is this fast enough. Should not matter if the filtering is done in the
 322                         # database or in code.
 323                         if ( $code !== $wgContLanguageCode ) {
 324                                 # Messages for particular language
 325                                 $escapedCode = $dbr->escapeLike( $code );
 326                                 $conds[] = "page_title like '%%/$escapedCode'";
 327                         } else {
 328                                 # Effectively disallows use of '/' character in NS_MEDIAWIKI for uses
 329                                 # other than language code.
 330                                 $conds[] = "page_title not like '%%/%%'";
 331                         }
 332                 }
 333
 334                 # Conditions to fetch oversized pages to ignore them
 335                 $bigConds = $conds;
 336                 $bigConds[] = 'page_len > ' . intval( $wgMaxMsgCacheEntrySize );
 337
 338                 # Load titles for all oversized pages in the MediaWiki namespace
 339                 $res = $dbr->select( 'page', 'page_title', $bigConds, __METHOD__ );
 340                 while ( $row = $dbr->fetchObject( $res ) ) {
 341                         $cache[$row->page_title] = '!TOO BIG';
 342                 }
 343                 $dbr->freeResult( $res );
 344
 345                 # Conditions to load the remaining pages with their contents
 346                 $smallConds = $conds;
 347                 $smallConds[] = 'page_latest=rev_id';
 348                 $smallConds[] = 'rev_text_id=old_id';
 349                 $smallConds[] = 'page_len <= ' . intval( $wgMaxMsgCacheEntrySize );
 350
 351                 $res = $dbr->select( array( 'page', 'revision', 'text' ),
 352                         array( 'page_title', 'old_text', 'old_flags' ),
 353                         $smallConds, __METHOD__ );
 354
 355                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 356                         $cache[$row->page_title] = ' ' . Revision::getRevisionText( $row );
 357                 }
 358                 $dbr->freeResult( $res );
 359
 360                 $cache['VERSION'] = MSG_CACHE_VERSION;
 361                 wfProfileOut( __METHOD__ );
 362                 return $cache;
 363         }
 364
 365         /**
 366          * Updates cache as necessary when message page is changed
 367          *
 368          * @param $title String: name of the page changed.
 369          * @param $text Mixed: new contents of the page.
 370          */
 371         public function replace( $title, $text ) {
 372                 global $wgMaxMsgCacheEntrySize;
 373                 wfProfileIn( __METHOD__ );
 374
 375
 376                 list( , $code ) = $this->figureMessage( $title );
 377
 378                 $cacheKey = wfMemcKey( 'messages', $code );
 379                 $this->load($code);
 380                 $this->lock($cacheKey);
 381
 382                 if ( is_array($this->mCache[$code]) ) {
 383                         $titleKey = wfMemcKey( 'messages', 'individual', $title );
 384
 385                         if ( $text === false ) {
 386                                 # Article was deleted
 387                                 unset( $this->mCache[$code][$title] );
 388                                 $this->mMemc->delete( $titleKey );
 389
 390                         } elseif ( strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
 391                                 # Check for size
 392                                 $this->mCache[$code][$title] = '!TOO BIG';
 393                                 $this->mMemc->set( $titleKey, ' ' . $text, $this->mExpiry );
 394
 395                         } else {
 396                                 $this->mCache[$code][$title] = ' ' . $text;
 397                                 $this->mMemc->delete( $titleKey );
 398                         }
 399
 400                         # Update caches
 401                         $this->saveToCaches( $this->mCache[$code], true, $code );
 402                 }
 403                 $this->unlock($cacheKey);
 404
 405                 // Also delete cached sidebar... just in case it is affected
 406                 global $parserMemc;
 407                 $sidebarKey = wfMemcKey( 'sidebar', $code );
 408                 $parserMemc->delete( $sidebarKey );
 409
 410                 wfRunHooks( "MessageCacheReplace", array( $title, $text ) );
 411
 412                 wfProfileOut( __METHOD__ );
 413         }
 414
 415         /**
 416          * Shortcut to update caches.
 417          *
 418          * @param $cache Array: cached messages with a version.
 419          * @param $cacheKey String: Identifier for the cache.
 420          * @param $memc Bool: Wether to update or not memcache.
 421          * @param $code String: Language code.
 422          * @return False on somekind of error.
 423          */
 424         protected function saveToCaches( $cache, $memc = true, $code = false ) {
 425                 wfProfileIn( __METHOD__ );
 426                 global $wgLocalMessageCache, $wgLocalMessageCacheSerialized;
 427
 428                 $cacheKey = wfMemcKey( 'messages', $code );
 429
 430                 $i = 0;
 431                 if ( $memc ) {
 432                         # Save in memcached
 433                         # Keep trying if it fails, this is kind of important
 434
 435                         for ($i=0; $i<20 &&
 436                                 !$this->mMemc->set( $cacheKey, $cache, $this->mExpiry );
 437                                 $i++ ) {
 438                                 usleep(mt_rand(500000,1500000));
 439                         }
 440                 }
 441
 442                 # Save to local cache
 443                 if ( $wgLocalMessageCache !== false ) {
 444                         $serialized = serialize( $cache );
 445                         $hash = md5( $serialized );
 446                         $this->mMemc->set( wfMemcKey( 'messages', $code, 'hash' ), $hash, $this->mExpiry );
 447                         if ($wgLocalMessageCacheSerialized) {
 448                                 $this->saveToLocal( $serialized, $hash, $code );
 449                         } else {
 450                                 $this->saveToScript( $cache, $hash, $code );
 451                         }
 452                 }
 453
 454                 if ( $i == 20 ) {
 455                         $success = false;
 456                 } else {
 457                         $success = true;
 458                 }
 459                 wfProfileOut( __METHOD__ );
 460                 return $success;
 461         }
 462
 463         /**
 464          * Returns success
 465          * Represents a write lock on the messages key
 466          */
 467         function lock($key) {
 468                 if ( !$this->mUseCache ) {
 469                         return true;
 470                 }
 471
 472                 $lockKey = $key . ':lock';
 473                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 474                         sleep(1);
 475                 }
 476
 477                 return $i >= MSG_WAIT_TIMEOUT;
 478         }
 479
 480         function unlock($key) {
 481                 if ( !$this->mUseCache ) {
 482                         return;
 483                 }
 484
 485                 $lockKey = $key . ':lock';
 486                 $this->mMemc->delete( $lockKey );
 487         }
 488
 489         /**
 490          * Get a message from either the content language or the user language.
 491          *
 492          * @param string $key The message cache key
 493          * @param bool $useDB Get the message from the DB, false to use only the localisation
 494          * @param string $langcode Code of the language to get the message for, if
 495          *                         it is a valid code create a language for that
 496          *                         language, if it is a string but not a valid code
 497          *                         then make a basic language object, if it is a
 498          *                         false boolean then use the current users
 499          *                         language (as a fallback for the old parameter
 500          *                         functionality), or if it is a true boolean then
 501          *                         use the wikis content language (also as a
 502          *                         fallback).
 503          * @param bool $isFullKey Specifies whether $key is a two part key "msg/lang".
 504          */
 505         function get( $key, $useDB = true, $langcode = true, $isFullKey = false ) {
 506                 global $wgContLanguageCode, $wgContLang;
 507
 508                 $lang = wfGetLangObj( $langcode );
 509                 $langcode = $lang->getCode();
 510
 511                 # If uninitialised, someone is trying to call this halfway through Setup.php
 512                 if( !$this->mInitialised ) {
 513                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 514                 }
 515
 516                 $message = false;
 517
 518                 # Normalise title-case input
 519                 $lckey = $wgContLang->lcfirst( $key );
 520                 $lckey = str_replace( ' ', '_', $lckey );
 521
 522                 # Try the MediaWiki namespace
 523                 if( !$this->mDisable && $useDB ) {
 524                         $title = $wgContLang->ucfirst( $lckey );
 525                         if(!$isFullKey && ( $langcode != $wgContLanguageCode ) ) {
 526                                 $title .= '/' . $langcode;
 527                         }
 528                         $message = $this->getMsgFromNamespace( $title, $langcode );
 529                 }
 530                 if( $message === false )
 531                         wfRunHooks( 'MessageNotInMwNs', array( &$message, $lckey, $langcode, $isFullKey ) );
 532
 533                 # Try the extension array
 534                 if ( $message === false && isset( $this->mExtensionMessages[$langcode][$lckey] ) ) {
 535                         $message = $this->mExtensionMessages[$langcode][$lckey];
 536                 }
 537                 if ( $message === false && isset( $this->mExtensionMessages['en'][$lckey] ) ) {
 538                         $message = $this->mExtensionMessages['en'][$lckey];
 539                 }
 540
 541                 # Try the array in the language object
 542                 if ( $message === false ) {
 543                         $message = $lang->getMessage( $lckey );
 544                         if ( is_null( $message ) ) {
 545                                 $message = false;
 546                         }
 547                 }
 548
 549                 # Try the array of another language
 550                 $pos = strrpos( $lckey, '/' );
 551                 if( $message === false && $pos !== false) {
 552                         $mkey = substr( $lckey, 0, $pos );
 553                         $code = substr( $lckey, $pos+1 );
 554                         if ( $code ) {
 555                                 # We may get calls for things that are http-urls from sidebar
 556                                 # Let's not load nonexistent languages for those
 557                                 $validCodes = array_keys( Language::getLanguageNames() );
 558                                 if ( in_array( $code, $validCodes ) ) {
 559                                         $message = Language::getMessageFor( $mkey, $code );
 560                                         if ( is_null( $message ) ) {
 561                                                 $message = false;
 562                                         }
 563                                 }
 564                         }
 565                 }
 566
 567                 # Is this a custom message? Try the default language in the db...
 568                 if( ($message === false || $message === '-' ) &&
 569                         !$this->mDisable && $useDB &&
 570                         !$isFullKey && ($langcode != $wgContLanguageCode) ) {
 571                         $message = $this->getMsgFromNamespace( $wgContLang->ucfirst( $lckey ), $wgContLanguageCode );
 572                 }
 573
 574                 # Final fallback
 575                 if( $message === false ) {
 576                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 577                 }
 578
 579                 # Fix whitespace
 580                 $message = strtr( $message,
 581                         array(
 582                                 # Fix for trailing whitespace, removed by textarea
 583                                 '&#32;' => ' ',
 584                                 # Fix for NBSP, converted to space by firefox
 585                                 '&nbsp;' => "\xc2\xa0",
 586                         ) );
 587
 588                 return $message;
 589         }
 590
 591         /**
 592          * Get a message from the MediaWiki namespace, with caching. The key must
 593          * first be converted to two-part lang/msg form if necessary.
 594          *
 595          * @param $title String: Message cache key with initial uppercase letter.
 596          * @param $code String: code denoting the language to try.
 597          */
 598         function getMsgFromNamespace( $title, $code ) {
 599                 $type = false;
 600                 $message = false;
 601
 602                 if ( $this->mUseCache ) {
 603                         $this->load( $code );
 604                         if (isset( $this->mCache[$code][$title] ) ) {
 605                                 $entry = $this->mCache[$code][$title];
 606                                 $type = substr( $entry, 0, 1 );
 607                                 if ( $type == ' ' ) {
 608                                         return substr( $entry, 1 );
 609                                 }
 610                         }
 611                 }
 612
 613                 # Call message hooks, in case they are defined
 614                 wfRunHooks('MessagesPreLoad', array( $title, &$message ) );
 615                 if ( $message !== false ) {
 616                         return $message;
 617                 }
 618
 619                 # If there is no cache entry and no placeholder, it doesn't exist
 620                 if ( $type !== '!' ) {
 621                         return false;
 622                 }
 623
 624                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 625
 626                 # Try the individual message cache
 627                 if ( $this->mUseCache ) {
 628                         $entry = $this->mMemc->get( $titleKey );
 629                         if ( $entry ) {
 630                                 $type = substr( $entry, 0, 1 );
 631
 632                                 if ( $type === ' ' ) {
 633                                         # Ok!
 634                                         $message = substr( $entry, 1 );
 635                                         $this->mCache[$code][$title] = $entry;
 636                                         return $message;
 637                                 } elseif ( $entry === '!NONEXISTENT' ) {
 638                                         return false;
 639                                 } else {
 640                                         # Corrupt/obsolete entry, delete it
 641                                         $this->mMemc->delete( $titleKey );
 642                                 }
 643
 644                         }
 645                 }
 646
 647                 # Try loading it from the DB
 648                 $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 649                 if( $revision ) {
 650                         $message = $revision->getText();
 651                         if ($this->mUseCache) {
 652                                 $this->mCache[$code][$title] = ' ' . $message;
 653                                 $this->mMemc->set( $titleKey, $message, $this->mExpiry );
 654                         }
 655                 } else {
 656                         # Negative caching
 657                         # Use some special text instead of false, because false gets converted to '' somewhere
 658                         $this->mMemc->set( $titleKey, '!NONEXISTENT', $this->mExpiry );
 659                         $this->mCache[$code][$title] = false;
 660                 }
 661                 return $message;
 662         }
 663
 664         function transform( $message, $interface = false, $language = null ) {
 665                 // Avoid creating parser if nothing to transfrom
 666                 if( strpos( $message, '{{' ) === false ) {
 667                         return $message;
 668                 }
 669
 670                 global $wgParser, $wgParserConf;
 671                 if ( !$this->mParser && isset( $wgParser ) ) {
 672                         # Do some initialisation so that we don't have to do it twice
 673                         $wgParser->firstCallInit();
 674                         # Clone it and store it
 675                         $class = $wgParserConf['class'];
 676                         if ( $class == 'Parser_DiffTest' ) {
 677                                 # Uncloneable
 678                                 $this->mParser = new $class( $wgParserConf );
 679                         } else {
 680                                 $this->mParser = clone $wgParser;
 681                         }
 682                         #wfDebug( __METHOD__ . ": following contents triggered transform: $message\n" );
 683                 }
 684                 if ( $this->mParser ) {
 685                         $popts = $this->getParserOptions();
 686                         $popts->setInterfaceMessage( $interface );
 687                         $popts->setTargetLanguage( $language );
 688                         $message = $this->mParser->transformMsg( $message, $popts );
 689                 }
 690                 return $message;
 691         }
 692
 693         function disable() { $this->mDisable = true; }
 694         function enable() { $this->mDisable = false; }
 695
 696         /** @deprecated */
 697         function disableTransform(){
 698                 wfDeprecated( __METHOD__ );
 699         }
 700         function enableTransform() {
 701                 wfDeprecated( __METHOD__ );
 702         }
 703         function setTransform( $x ) {
 704                 wfDeprecated( __METHOD__ );
 705         }
 706         function getTransform() {
 707                 wfDeprecated( __METHOD__ );
 708                 return false;
 709         }
 710
 711         /**
 712          * Add a message to the cache
 713          *
 714          * @param mixed $key
 715          * @param mixed $value
 716          * @param string $lang The messages language, English by default
 717          */
 718         function addMessage( $key, $value, $lang = 'en' ) {
 719                 global $wgContLang;
 720                 # Normalise title-case input
 721                 $lckey = str_replace( ' ', '_', $wgContLang->lcfirst( $key ) );
 722                 $this->mExtensionMessages[$lang][$lckey] = $value;
 723         }
 724
 725         /**
 726          * Add an associative array of message to the cache
 727          *
 728          * @param array $messages An associative array of key => values to be added
 729          * @param string $lang The messages language, English by default
 730          */
 731         function addMessages( $messages, $lang = 'en' ) {
 732                 wfProfileIn( __METHOD__ );
 733                 if ( !is_array( $messages ) ) {
 734                         throw new MWException( __METHOD__.': Invalid message array' );
 735                 }
 736                 if ( isset( $this->mExtensionMessages[$lang] ) ) {
 737                         $this->mExtensionMessages[$lang] = $messages + $this->mExtensionMessages[$lang];
 738                 } else {
 739                         $this->mExtensionMessages[$lang] = $messages;
 740                 }
 741                 wfProfileOut( __METHOD__ );
 742         }
 743
 744         /**
 745          * Add a 2-D array of messages by lang. Useful for extensions.
 746          *
 747          * @param array $messages The array to be added
 748          */
 749         function addMessagesByLang( $messages ) {
 750                 wfProfileIn( __METHOD__ );
 751                 foreach ( $messages as $key => $value ) {
 752                         $this->addMessages( $value, $key );
 753                 }
 754                 wfProfileOut( __METHOD__ );
 755         }
 756
 757         /**
 758          * Get the extension messages for a specific language. Only English, interface
 759          * and content language are guaranteed to be loaded.
 760          *
 761          * @param string $lang The messages language, English by default
 762          */
 763         function getExtensionMessagesFor( $lang = 'en' ) {
 764                 wfProfileIn( __METHOD__ );
 765                 $messages = array();
 766                 if ( isset( $this->mExtensionMessages[$lang] ) ) {
 767                         $messages = $this->mExtensionMessages[$lang];
 768                 }
 769                 if ( $lang != 'en' ) {
 770                         $messages = $messages + $this->mExtensionMessages['en'];
 771                 }
 772                 wfProfileOut( __METHOD__ );
 773                 return $messages;
 774         }
 775
 776         /**
 777          * Clear all stored messages. Mainly used after a mass rebuild.
 778          */
 779         function clear() {
 780                 if( $this->mUseCache ) {
 781                         $langs = Language::getLanguageNames( false );
 782                         foreach ( array_keys($langs) as $code ) {
 783                                 # Global cache
 784                                 $this->mMemc->delete( wfMemcKey( 'messages', $code ) );
 785                                 # Invalidate all local caches
 786                                 $this->mMemc->delete( wfMemcKey( 'messages', $code, 'hash' ) );
 787                         }
 788                 }
 789         }
 790
 791         function loadAllMessages( $lang = false ) {
 792                 global $wgExtensionMessagesFiles;
 793                 $key = $lang === false ? '*' : $lang;
 794                 if ( isset( $this->mAllMessagesLoaded[$key] ) ) {
 795                         return;
 796                 }
 797                 $this->mAllMessagesLoaded[$key] = true;
 798
 799                 # Some extensions will load their messages when you load their class file
 800                 wfLoadAllExtensions();
 801                 # Others will respond to this hook
 802                 wfRunHooks( 'LoadAllMessages', array( $this ) );
 803                 # Some register their messages in $wgExtensionMessagesFiles
 804                 foreach ( $wgExtensionMessagesFiles as $name => $file ) {
 805                         wfLoadExtensionMessages( $name, $lang );
 806                 }
 807                 # Still others will respond to neither, they are EVIL. We sometimes need to know!
 808         }
 809
 810         /**
 811          * Load messages from a given file
 812          *
 813          * @param string $filename Filename of file to load.
 814          * @param string $langcode Language to load messages for, or false for
 815      *                         default behvaiour (en, content language and user
 816      *                         language).
 817          */
 818         function loadMessagesFile( $filename, $langcode = false ) {
 819                 global $wgLang, $wgContLang;
 820                 wfProfileIn( __METHOD__ );
 821                 $messages = $magicWords = false;
 822                 require( $filename );
 823
 824                 $validCodes = Language::getLanguageNames();
 825                 if( is_string( $langcode ) && array_key_exists( $langcode, $validCodes ) ) {
 826                         # Load messages for given language code.
 827                         $this->processMessagesArray( $messages, $langcode );
 828                 } elseif( is_string( $langcode ) && !array_key_exists( $langcode, $validCodes ) ) {
 829                         wfDebug( "Invalid language '$langcode' code passed to MessageCache::loadMessagesFile()" );
 830                 } else {
 831                         # Load only languages that are usually used, and merge all
 832                         # fallbacks, except English.
 833                         $langs = array_unique( array( 'en', $wgContLang->getCode(), $wgLang->getCode() ) );
 834                         foreach( $langs as $code ) {
 835                                 $this->processMessagesArray( $messages, $code );
 836                         }
 837                 }
 838
 839                 if ( $magicWords !== false ) {
 840                         global $wgContLang;
 841                         $wgContLang->addMagicWordsByLang( $magicWords );
 842                 }
 843                 wfProfileOut( __METHOD__ );
 844         }
 845
 846         /**
 847          * Process an array of messages, loading it into the message cache.
 848          *
 849          * @param array $messages Messages array.
 850          * @param string $langcode Language code to process.
 851          */
 852         function processMessagesArray( $messages, $langcode ) {
 853                 wfProfileIn( __METHOD__ );
 854                 $fallbackCode = $langcode;
 855                 $mergedMessages = array();
 856                 do {
 857                         if ( isset($messages[$fallbackCode]) ) {
 858                                 $mergedMessages += $messages[$fallbackCode];
 859                         }
 860                         $fallbackCode = Language::getFallbackfor( $fallbackCode );
 861                 } while( $fallbackCode && $fallbackCode !== 'en' );
 862
 863                 if ( !empty($mergedMessages) )
 864                         $this->addMessages( $mergedMessages, $langcode );
 865                 wfProfileOut( __METHOD__ );
 866         }
 867
 868         public function figureMessage( $key ) {
 869                 global $wgContLanguageCode;
 870                 $pieces = explode( '/', $key );
 871                 if( count( $pieces ) < 2 )
 872                         return array( $key, $wgContLanguageCode );
 873
 874                 $lang = array_pop( $pieces );
 875                 $validCodes = Language::getLanguageNames();
 876                 if( !array_key_exists( $lang, $validCodes ) )
 877                         return array( $key, $wgContLanguageCode );
 878
 879                 $message = implode( '/', $pieces );
 880                 return array( $message, $lang );
 881         }
 882
 883 }