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                 $this->mParser = null;
  42         }
  43
  44
  45         /**
  46          * ParserOptions is lazy initialised.
  47          */
  48         function getParserOptions() {
  49                 if ( !$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                         $cache = $this->loadFromDB( $code );
 264                         $success = $this->setCache( $cache, $code );
 265                         if ( $success ) {
 266                                 $this->saveToCaches( $cache, true, $code );
 267                         }
 268
 269                         $this->unlock($cacheKey);
 270                 }
 271
 272                 if ( !$success ) {
 273                         # Bad luck... this should not happen
 274                         $where[] = 'loading FAILED - cache is disabled';
 275                         $info = implode( ', ', $where );
 276                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 277                         $this->mDisable = true;
 278                         $this->mCache = false;
 279                 } else {
 280                         # All good, just record the success
 281                         $info = implode( ', ', $where );
 282                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 283                         $this->mLoadedLanguages[$code] = true;
 284                 }
 285                 wfProfileOut( __METHOD__ );
 286                 return $success;
 287         }
 288
 289         /**
 290          * Loads cacheable messages from the database. Messages bigger than
 291          * $wgMaxMsgCacheEntrySize are assigned a special value, and are loaded
 292          * on-demand from the database later.
 293          *
 294          * @param $code Optional language code, see documenation of load().
 295          * @return Array: Loaded messages for storing in caches.
 296          */
 297         function loadFromDB( $code = false ) {
 298                 wfProfileIn( __METHOD__ );
 299                 global $wgMaxMsgCacheEntrySize, $wgContLanguageCode;
 300                 $dbr = wfGetDB( DB_SLAVE );
 301                 $cache = array();
 302
 303                 # Common conditions
 304                 $conds = array(
 305                         'page_is_redirect' => 0,
 306                         'page_namespace' => NS_MEDIAWIKI,
 307                 );
 308
 309                 if ( $code ) {
 310                         # Is this fast enough. Should not matter if the filtering is done in the
 311                         # database or in code.
 312                         if ( $code !== $wgContLanguageCode ) {
 313                                 # Messages for particular language
 314                                 $escapedCode = $dbr->escapeLike( $code );
 315                                 $conds[] = "page_title like '%%/$escapedCode'";
 316                         } else {
 317                                 # Effectively disallows use of '/' character in NS_MEDIAWIKI for uses
 318                                 # other than language code.
 319                                 $conds[] = "page_title not like '%%/%%'";
 320                         }
 321                 }
 322
 323                 # Conditions to fetch oversized pages to ignore them
 324                 $bigConds = $conds;
 325                 $bigConds[] = 'page_len > ' . intval( $wgMaxMsgCacheEntrySize );
 326
 327                 # Load titles for all oversized pages in the MediaWiki namespace
 328                 $res = $dbr->select( 'page', 'page_title', $bigConds, __METHOD__ );
 329                 while ( $row = $dbr->fetchObject( $res ) ) {
 330                         $cache[$row->page_title] = '!TOO BIG';
 331                 }
 332                 $dbr->freeResult( $res );
 333
 334                 # Conditions to load the remaining pages with their contents
 335                 $smallConds = $conds;
 336                 $smallConds[] = 'page_latest=rev_id';
 337                 $smallConds[] = 'rev_text_id=old_id';
 338                 $smallConds[] = 'page_len <= ' . intval( $wgMaxMsgCacheEntrySize );
 339
 340                 $res = $dbr->select( array( 'page', 'revision', 'text' ),
 341                         array( 'page_title', 'old_text', 'old_flags' ),
 342                         $smallConds, __METHOD__ );
 343
 344                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 345                         $cache[$row->page_title] = ' ' . Revision::getRevisionText( $row );
 346                 }
 347                 $dbr->freeResult( $res );
 348
 349                 $cache['VERSION'] = MSG_CACHE_VERSION;
 350                 wfProfileOut( __METHOD__ );
 351                 return $cache;
 352         }
 353
 354         /**
 355          * Updates cache as necessary when message page is changed
 356          *
 357          * @param $title String: name of the page changed.
 358          * @param $text Mixed: new contents of the page.
 359          */
 360         public function replace( $title, $text ) {
 361                 global $wgMaxMsgCacheEntrySize;
 362                 wfProfileIn( __METHOD__ );
 363
 364
 365                 list( , $code ) = $this->figureMessage( $title );
 366
 367                 $cacheKey = wfMemcKey( 'messages', $code );
 368                 $this->load($code);
 369                 $this->lock($cacheKey);
 370
 371                 if ( is_array($this->mCache[$code]) ) {
 372                         $titleKey = wfMemcKey( 'messages', 'individual', $title );
 373
 374                         if ( $text === false ) {
 375                                 # Article was deleted
 376                                 unset( $this->mCache[$code][$title] );
 377                                 $this->mMemc->delete( $titleKey );
 378
 379                         } elseif ( strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
 380                                 # Check for size
 381                                 $this->mCache[$code][$title] = '!TOO BIG';
 382                                 $this->mMemc->set( $titleKey, ' ' . $text, $this->mExpiry );
 383
 384                         } else {
 385                                 $this->mCache[$code][$title] = ' ' . $text;
 386                                 $this->mMemc->delete( $titleKey );
 387                         }
 388
 389                         # Update caches
 390                         $this->saveToCaches( $this->mCache[$code], true, $code );
 391                 }
 392                 $this->unlock($cacheKey);
 393
 394                 // Also delete cached sidebar... just in case it is affected
 395                 global $parserMemc;
 396                 $sidebarKey = wfMemcKey( 'sidebar', $code );
 397                 $parserMemc->delete( $sidebarKey );
 398
 399                 wfProfileOut( __METHOD__ );
 400         }
 401
 402         /**
 403          * Shortcut to update caches.
 404          *
 405          * @param $cache Array: cached messages with a version.
 406          * @param $cacheKey String: Identifier for the cache.
 407          * @param $memc Bool: Wether to update or not memcache.
 408          * @param $code String: Language code.
 409          * @return False on somekind of error.
 410          */
 411         protected function saveToCaches( $cache, $memc = true, $code = false ) {
 412                 wfProfileIn( __METHOD__ );
 413                 global $wgLocalMessageCache, $wgLocalMessageCacheSerialized;
 414
 415                 $cacheKey = wfMemcKey( 'messages', $code );
 416                 $statusKey = wfMemcKey( 'messages', $code, 'status' );
 417
 418                 $success = $this->mMemc->add( $statusKey, 'loading', MSG_LOAD_TIMEOUT );
 419                 if ( !$success ) return true; # Other process should be updating them now
 420
 421                 $i = 0;
 422                 if ( $memc ) {
 423                         # Save in memcached
 424                         # Keep trying if it fails, this is kind of important
 425
 426                         for ($i=0; $i<20 &&
 427                                 !$this->mMemc->set( $cacheKey, $cache, $this->mExpiry );
 428                                 $i++ ) {
 429                                 usleep(mt_rand(500000,1500000));
 430                         }
 431                 }
 432
 433                 # Save to local cache
 434                 if ( $wgLocalMessageCache !== false ) {
 435                         $serialized = serialize( $cache );
 436                         $hash = md5( $serialized );
 437                         $this->mMemc->set( wfMemcKey( 'messages', $code, 'hash' ), $hash, $this->mExpiry );
 438                         if ($wgLocalMessageCacheSerialized) {
 439                                 $this->saveToLocal( $serialized, $hash, $code );
 440                         } else {
 441                                 $this->saveToScript( $cache, $hash, $code );
 442                         }
 443                 }
 444
 445                 if ( $i == 20 ) {
 446                         $this->mMemc->set( $statusKey, 'error', 60*5 );
 447                         wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 448                         $success = false;
 449                 } else {
 450                         $this->mMemc->delete( $statusKey );
 451                         $success = true;
 452                 }
 453                 wfProfileOut( __METHOD__ );
 454                 return $success;
 455         }
 456
 457         /**
 458          * Returns success
 459          * Represents a write lock on the messages key
 460          */
 461         function lock($key) {
 462                 if ( !$this->mUseCache ) {
 463                         return true;
 464                 }
 465
 466                 $lockKey = $key . ':lock';
 467                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 468                         sleep(1);
 469                 }
 470
 471                 return $i >= MSG_WAIT_TIMEOUT;
 472         }
 473
 474         function unlock($key) {
 475                 if ( !$this->mUseCache ) {
 476                         return;
 477                 }
 478
 479                 $lockKey = $key . ':lock';
 480                 $this->mMemc->delete( $lockKey );
 481         }
 482
 483         /**
 484          * Get a message from either the content language or the user language.
 485          *
 486          * @param string $key The message cache key
 487          * @param bool $useDB Get the message from the DB, false to use only the localisation
 488          * @param string $langcode Code of the language to get the message for, if
 489          *                         it is a valid code create a language for that
 490          *                         language, if it is a string but not a valid code
 491          *                         then make a basic language object, if it is a
 492          *                         false boolean then use the current users
 493          *                         language (as a fallback for the old parameter
 494          *                         functionality), or if it is a true boolean then
 495          *                         use the wikis content language (also as a
 496          *                         fallback).
 497          * @param bool $isFullKey Specifies whether $key is a two part key "lang/msg".
 498          */
 499         function get( $key, $useDB = true, $langcode = true, $isFullKey = false ) {
 500                 global $wgContLanguageCode, $wgContLang;
 501
 502                 $lang = wfGetLangObj( $langcode );
 503                 $langcode = $lang->getCode();
 504
 505                 # If uninitialised, someone is trying to call this halfway through Setup.php
 506                 if( !$this->mInitialised ) {
 507                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 508                 }
 509
 510                 $message = false;
 511
 512                 # Normalise title-case input
 513                 $lckey = $wgContLang->lcfirst( $key );
 514                 $lckey = str_replace( ' ', '_', $lckey );
 515
 516                 # Try the MediaWiki namespace
 517                 if( !$this->mDisable && $useDB ) {
 518                         $title = $wgContLang->ucfirst( $lckey );
 519                         if(!$isFullKey && ($langcode != $wgContLanguageCode) ) {
 520                                 $title .= '/' . $langcode;
 521                         }
 522                         $message = $this->getMsgFromNamespace( $title, $langcode );
 523                 }
 524
 525                 # Try the extension array
 526                 if ( $message === false && isset( $this->mExtensionMessages[$langcode][$lckey] ) ) {
 527                         $message = $this->mExtensionMessages[$langcode][$lckey];
 528                 }
 529                 if ( $message === false && isset( $this->mExtensionMessages['en'][$lckey] ) ) {
 530                         $message = $this->mExtensionMessages['en'][$lckey];
 531                 }
 532
 533                 # Try the array in the language object
 534                 if ( $message === false ) {
 535                         $message = $lang->getMessage( $lckey );
 536                         if ( is_null( $message ) ) {
 537                                 $message = false;
 538                         }
 539                 }
 540
 541                 # Try the array of another language
 542                 $pos = strrpos( $lckey, '/' );
 543                 if( $message === false && $pos !== false) {
 544                         $mkey = substr( $lckey, 0, $pos );
 545                         $code = substr( $lckey, $pos+1 );
 546                         if ( $code ) {
 547                                 # We may get calls for things that are http-urls from sidebar
 548                                 # Let's not load nonexistent languages for those
 549                                 $validCodes = array_keys( Language::getLanguageNames() );
 550                                 if ( in_array( $code, $validCodes ) ) {
 551                                         $message = Language::getMessageFor( $mkey, $code );
 552                                         if ( is_null( $message ) ) {
 553                                                 $message = false;
 554                                         }
 555                                 }
 556                         }
 557                 }
 558
 559                 # Is this a custom message? Try the default language in the db...
 560                 if( ($message === false || $message === '-' ) &&
 561                         !$this->mDisable && $useDB &&
 562                         !$isFullKey && ($langcode != $wgContLanguageCode) ) {
 563                         $message = $this->getMsgFromNamespace( $wgContLang->ucfirst( $lckey ), $wgContLanguageCode );
 564                 }
 565
 566                 # Final fallback
 567                 if( $message === false ) {
 568                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 569                 }
 570                 return $message;
 571         }
 572
 573         /**
 574          * Get a message from the MediaWiki namespace, with caching. The key must
 575          * first be converted to two-part lang/msg form if necessary.
 576          *
 577          * @param $title String: Message cache key with initial uppercase letter.
 578          * @param $code String: code denoting the language to try.
 579          */
 580         function getMsgFromNamespace( $title, $code ) {
 581                 $type = false;
 582                 $message = false;
 583
 584                 if ( $this->mUseCache ) {
 585                         $this->load( $code );
 586                         if (isset( $this->mCache[$code][$title] ) ) {
 587                                 $entry = $this->mCache[$code][$title];
 588                                 $type = substr( $entry, 0, 1 );
 589                                 if ( $type == ' ' ) {
 590                                         return substr( $entry, 1 );
 591                                 }
 592                         }
 593                 }
 594
 595                 # Call message hooks, in case they are defined
 596                 wfRunHooks('MessagesPreLoad', array( $title, &$message ) );
 597                 if ( $message !== false ) {
 598                         return $message;
 599                 }
 600
 601                 # If there is no cache entry and no placeholder, it doesn't exist
 602                 if ( $type !== '!' ) {
 603                         return false;
 604                 }
 605
 606                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 607
 608                 # Try the individual message cache
 609                 if ( $this->mUseCache ) {
 610                         $entry = $this->mMemc->get( $titleKey );
 611                         if ( $entry ) {
 612                                 $type = substr( $entry, 0, 1 );
 613
 614                                 if ( $type === ' ' ) {
 615                                         # Ok!
 616                                         $message = substr( $entry, 1 );
 617                                         $this->mCache[$code][$title] = $entry;
 618                                         return $message;
 619                                 } elseif ( $entry === '!NONEXISTENT' ) {
 620                                         return false;
 621                                 } else {
 622                                         # Corrupt/obsolete entry, delete it
 623                                         $this->mMemc->delete( $titleKey );
 624                                 }
 625
 626                         }
 627                 }
 628
 629                 # Try loading it from the DB
 630                 $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 631                 if( $revision ) {
 632                         $message = $revision->getText();
 633                         if ($this->mUseCache) {
 634                                 $this->mCache[$code][$title] = ' ' . $message;
 635                                 $this->mMemc->set( $titleKey, $message, $this->mExpiry );
 636                         }
 637                 } else {
 638                         # Negative caching
 639                         # Use some special text instead of false, because false gets converted to '' somewhere
 640                         $this->mMemc->set( $titleKey, '!NONEXISTENT', $this->mExpiry );
 641                         $this->mCache[$code][$title] = false;
 642                 }
 643                 return $message;
 644         }
 645
 646         function transform( $message, $interface = false ) {
 647                 // Avoid creating parser if nothing to transfrom
 648                 if( strpos( $message, '{{' ) === false ) {
 649                         return $message;
 650                 }
 651
 652                 global $wgParser, $wgParserConf;
 653                 if ( !$this->mParser && isset( $wgParser ) ) {
 654                         # Do some initialisation so that we don't have to do it twice
 655                         $wgParser->firstCallInit();
 656                         # Clone it and store it
 657                         $class = $wgParserConf['class'];
 658                         if ( $class == 'Parser_DiffTest' ) {
 659                                 # Uncloneable
 660                                 $this->mParser = new $class( $wgParserConf );
 661                         } else {
 662                                 $this->mParser = clone $wgParser;
 663                         }
 664                         #wfDebug( __METHOD__ . ": following contents triggered transform: $message\n" );
 665                 }
 666                 if ( $this->mParser ) {
 667                         $popts = $this->getParserOptions();
 668                         $popts->setInterfaceMessage( $interface );
 669                         $message = $this->mParser->transformMsg( $message, $popts );
 670                 }
 671                 return $message;
 672         }
 673
 674         function disable() { $this->mDisable = true; }
 675         function enable() { $this->mDisable = false; }
 676
 677         /** @deprecated */
 678         function disableTransform(){
 679                 wfDeprecated( __METHOD__ );
 680         }
 681         function enableTransform() {
 682                 wfDeprecated( __METHOD__ );
 683         }
 684         function setTransform( $x ) {
 685                 wfDeprecated( __METHOD__ );
 686         }
 687         function getTransform() {
 688                 wfDeprecated( __METHOD__ );
 689                 return false;
 690         }
 691
 692         /**
 693          * Add a message to the cache
 694          *
 695          * @param mixed $key
 696          * @param mixed $value
 697          * @param string $lang The messages language, English by default
 698          */
 699         function addMessage( $key, $value, $lang = 'en' ) {
 700                 $this->mExtensionMessages[$lang][$key] = $value;
 701         }
 702
 703         /**
 704          * Add an associative array of message to the cache
 705          *
 706          * @param array $messages An associative array of key => values to be added
 707          * @param string $lang The messages language, English by default
 708          */
 709         function addMessages( $messages, $lang = 'en' ) {
 710                 wfProfileIn( __METHOD__ );
 711                 if ( !is_array( $messages ) ) {
 712                         throw new MWException( __METHOD__.': Invalid message array' );
 713                 }
 714                 if ( isset( $this->mExtensionMessages[$lang] ) ) {
 715                         $this->mExtensionMessages[$lang] = $messages + $this->mExtensionMessages[$lang];
 716                 } else {
 717                         $this->mExtensionMessages[$lang] = $messages;
 718                 }
 719                 wfProfileOut( __METHOD__ );
 720         }
 721
 722         /**
 723          * Add a 2-D array of messages by lang. Useful for extensions.
 724          *
 725          * @param array $messages The array to be added
 726          */
 727         function addMessagesByLang( $messages ) {
 728                 wfProfileIn( __METHOD__ );
 729                 foreach ( $messages as $key => $value ) {
 730                         $this->addMessages( $value, $key );
 731                 }
 732                 wfProfileOut( __METHOD__ );
 733         }
 734
 735         /**
 736          * Get the extension messages for a specific language. Only English, interface
 737          * and content language are guaranteed to be loaded.
 738          *
 739          * @param string $lang The messages language, English by default
 740          */
 741         function getExtensionMessagesFor( $lang = 'en' ) {
 742                 wfProfileIn( __METHOD__ );
 743                 $messages = array();
 744                 if ( isset( $this->mExtensionMessages[$lang] ) ) {
 745                         $messages = $this->mExtensionMessages[$lang];
 746                 }
 747                 if ( $lang != 'en' ) {
 748                         $messages = $messages + $this->mExtensionMessages['en'];
 749                 }
 750                 wfProfileOut( __METHOD__ );
 751                 return $messages;
 752         }
 753
 754         /**
 755          * Clear all stored messages. Mainly used after a mass rebuild.
 756          */
 757         function clear() {
 758                 if( $this->mUseCache ) {
 759                         $langs = Language::getLanguageNames( false );
 760                         foreach ( array_keys($langs) as $code ) {
 761                                 # Global cache
 762                                 $this->mMemc->delete( wfMemcKey( 'messages', $code ) );
 763                                 # Invalidate all local caches
 764                                 $this->mMemc->delete( wfMemcKey( 'messages', $code, 'hash' ) );
 765                         }
 766                 }
 767         }
 768
 769         function loadAllMessages() {
 770                 global $wgExtensionMessagesFiles;
 771                 if ( $this->mAllMessagesLoaded ) {
 772                         return;
 773                 }
 774                 $this->mAllMessagesLoaded = true;
 775
 776                 # Some extensions will load their messages when you load their class file
 777                 wfLoadAllExtensions();
 778                 # Others will respond to this hook
 779                 wfRunHooks( 'LoadAllMessages' );
 780                 # Some register their messages in $wgExtensionMessagesFiles
 781                 foreach ( $wgExtensionMessagesFiles as $name => $file ) {
 782                         wfLoadExtensionMessages( $name );
 783                 }
 784                 # Still others will respond to neither, they are EVIL. We sometimes need to know!
 785         }
 786
 787         /**
 788          * Load messages from a given file
 789          *
 790          * @param string $filename Filename of file to load.
 791          * @param string $langcode Language to load messages for, or false for
 792      *                         default behvaiour (en, content language and user
 793      *                         language).
 794          */
 795         function loadMessagesFile( $filename, $langcode = false ) {
 796                 global $wgLang, $wgContLang;
 797                 $messages = $magicWords = false;
 798                 require( $filename );
 799
 800                 $validCodes = Language::getLanguageNames();
 801                 if( is_string( $langcode ) && array_key_exists( $langcode, $validCodes ) ) {
 802                         # Load messages for given language code.
 803                         $this->processMessagesArray( $messages, $langcode );
 804                 } elseif( is_string( $langcode ) && !array_key_exists( $langcode, $validCodes ) ) {
 805                         wfDebug( "Invalid language '$langcode' code passed to MessageCache::loadMessagesFile()" );
 806                 } else {
 807                         # Load only languages that are usually used, and merge all
 808                         # fallbacks, except English.
 809                         $langs = array_unique( array( 'en', $wgContLang->getCode(), $wgLang->getCode() ) );
 810                         foreach( $langs as $code ) {
 811                                 $this->processMessagesArray( $messages, $code );
 812                         }
 813                 }
 814
 815                 if ( $magicWords !== false ) {
 816                         global $wgContLang;
 817                         $wgContLang->addMagicWordsByLang( $magicWords );
 818                 }
 819         }
 820
 821         /**
 822          * Process an array of messages, loading it into the message cache.
 823          *
 824          * @param array $messages Messages array.
 825          * @param string $langcode Language code to process.
 826          */
 827         function processMessagesArray( $messages, $langcode ) {
 828                 $fallbackCode = $langcode;
 829                 $mergedMessages = array();
 830                 do {
 831                         if ( isset($messages[$fallbackCode]) ) {
 832                                 $mergedMessages += $messages[$fallbackCode];
 833                         }
 834                         $fallbackCode = Language::getFallbackfor( $fallbackCode );
 835                 } while( $fallbackCode && $fallbackCode !== 'en' );
 836
 837                 if ( !empty($mergedMessages) )
 838                         $this->addMessages( $mergedMessages, $langcode );
 839         }
 840
 841         public function figureMessage( $key ) {
 842                 global $wgContLanguageCode;
 843                 $pieces = explode('/', $key, 2);
 844
 845                 $key = $pieces[0];
 846
 847                 # Language the user is translating to
 848                 $langCode = isset($pieces[1]) ? $pieces[1] : $wgContLanguageCode;
 849                 return array( $key, $langCode );
 850         }
 851
 852 }