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         var $mCache, $mUseCache, $mDisable, $mExpiry;
  22         var $mMemcKey, $mKeys, $mParserOptions, $mParser;
  23         var $mExtensionMessages = array();
  24         var $mInitialised = false;
  25         var $mAllMessagesLoaded; // Extension messages
  26
  27         function __construct( &$memCached, $useDB, $expiry, $memcPrefix) {
  28                 wfProfileIn( __METHOD__ );
  29
  30                 $this->mUseCache = !is_null( $memCached );
  31                 $this->mMemc = &$memCached;
  32                 $this->mDisable = !$useDB;
  33                 $this->mExpiry = $expiry;
  34                 $this->mDisableTransform = false;
  35                 $this->mMemcKey = $memcPrefix.':messages';
  36                 $this->mKeys = false; # initialised on demand
  37                 $this->mInitialised = true;
  38                 $this->mParser = null;
  39
  40                 wfProfileOut( __METHOD__ );
  41         }
  42
  43
  44         /**
  45          * ParserOptions is lazy initialised.
  46          * Access should probably be protected.
  47          */
  48         function getParserOptions() {
  49                 if ( !$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();
  68                 if ( $code ) $filename .= '-' . $code;
  69
  70                 # Check file existence
  71                 wfSuppressWarnings();
  72                 $file = fopen( $filename, 'r' );
  73                 wfRestoreWarnings();
  74                 if ( !$file ) {
  75                         return false; // No cache file
  76                 }
  77
  78                 if ( $wgLocalMessageCacheSerialized ) {
  79                         // Check to see if the file has the hash specified
  80                         $localHash = fread( $file, 32 );
  81                         if ( $hash === $localHash ) {
  82                                 // All good, get the rest of it
  83                                 $serialized = '';
  84                                 while ( !feof( $file ) ) {
  85                                         $serialized .= fread( $file, 100000 );
  86                                 }
  87                                 fclose( $file );
  88                                 return $this->setCache( unserialize( $serialized ) );
  89                         } else {
  90                                 fclose( $file );
  91                                 return false; // Wrong hash
  92                         }
  93                 } else {
  94                         $localHash=substr(fread($file,40),8);
  95                         fclose($file);
  96                         if ($hash!=$localHash) {
  97                                 return false; // Wrong hash
  98                         }
  99
 100                         require( $filename );
 101                         return $this->setCache( $this->mCache );
 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();
 112                 if ( $code ) $filename .= '-' . $code;
 113
 114                 # Make sure the directories exist
 115                 $this->createCacheDir( $wgLocalMessageCache );
 116
 117                 $file = fopen( $filename, 'w' );
 118                 if ( !$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();
 132                 if ( $code ) $filename .= '-' . $code;
 133                 $tempFilename = $filename . '.tmp';
 134
 135                 # Make sure the directories exist
 136                 $this->createCacheDir( $wgLocalMessageCache );
 137
 138                 $file = fopen( $tempFilename, 'w');
 139                 fwrite($file,"<?php\n//$hash\n\n \$this->mCache = array(");
 140
 141                 foreach ($array as $key => $message) {
 142                         $key = $this->escapeForScript($key);
 143                         $messages = $this->escapeForScript($message);
 144                         fwrite($file, "'$key' => '$message',\n");
 145                 }
 146
 147                 fwrite($file,");\n?>");
 148                 fclose($file);
 149                 rename($tempFilename, $filename);
 150         }
 151
 152         /**
 153          * Creates directory with correct permissions.
 154          *
 155          * @param $path String: path that is created if it does not exist.
 156          */
 157         protected function createCacheDir( $path ) {
 158                 $oldUmask = umask( 0 );
 159                 wfMkdirParents( $path, 0777 );
 160                 umask( $oldUmask );
 161         }
 162
 163         function escapeForScript($string) {
 164                 $string = str_replace( '\\', '\\\\', $string );
 165                 $string = str_replace( '\'', '\\\'', $string );
 166                 return $string;
 167         }
 168
 169         /**
 170          * Set the cache to $cache, if it is valid. Otherwise set the cache to false.
 171          */
 172         function setCache( $cache ) {
 173                 if ( isset( $cache['VERSION'] ) && $cache['VERSION'] == MSG_CACHE_VERSION ) {
 174                         if ( $this->mCache ) {
 175                                 $this->mCache = $cache + $this->mCache;
 176                         } else {
 177                                 $this->mCache = $cache;
 178                         }
 179                         return true;
 180                 } else {
 181                         return false;
 182                 }
 183         }
 184
 185         /**
 186          * Loads messages from caches or from database in this order:
 187          * (1) local message cache (if $wgLocalMessageCache is enabled)
 188          * (2) memcached
 189          * (3) from the database.
 190          *
 191          * When succesfully loading from (2) or (3), all higher level caches are
 192          * updated for the newest version.
 193          *
 194          * Nothing is loaded if  member variable mDisabled is true, either manually
 195          * set by calling code or if message loading fails (is this possible?).
 196          *
 197          * Returns true if cache is already populated or it was succesfully populated,
 198          * or false if populating empty cache fails. Also returns true if MessageCache
 199          * is disabled.
 200          *
 201          * @param $code Mixed: if evaluates to false, messages for all languages is
 202          *              loaded and stored in cache as one object. If code is provided
 203          *              and $wgPerLanguageCaching is true, messages are loaded per
 204          *              language and stored individually in caches 1 to 2.
 205          */
 206         function load( $code = false ) {
 207                 global $wgLocalMessageCache, $wgPerLanguageCaching;
 208
 209                 if ( !$this->mUseCache ) {
 210                         return true;
 211                 }
 212
 213                 # Keep track of loaded messages. Either array of loaded codes as keys,
 214                 # or just true if all languages are loaded.
 215                 static $loaded = false;
 216
 217                 if ( !$wgPerLanguageCaching ) {
 218                         // Disable language separation for normal use case
 219                         $code = false;
 220                 } elseif( !is_string( $code ) ) {
 221                         # This isn't really nice, so at least make a note about it
 222                         wfDebug( __METHOD__ . " called without providing a language code\n" );
 223                 }
 224
 225                 # Don't do double loading...
 226                 if ( $loaded === true || ($code && isset($loaded[$code])) ) return true;
 227
 228                 # Adjust cache key if we are handling only single language
 229                 $cacheKey = wfMemcKeyLang( $this->mMemcKey, $code );
 230
 231                 # 8 lines of code just to say (once) that message cache is disabled
 232                 if ( $this->mDisable ) {
 233                         static $shownDisabled = false;
 234                         if ( !$shownDisabled ) {
 235                                 wfDebug( __METHOD__ . ": disabled\n" );
 236                                 $shownDisabled = true;
 237                         }
 238                         return true;
 239                 }
 240
 241                 # Loading code starts
 242                 wfProfileIn( __METHOD__ );
 243                 $success = false; # Keep track of success
 244                 $where = array(); # Debug info, delayed to avoid spamming debug log too much
 245
 246                 # (1) local cache
 247                 # Hash of the contents is stored in memcache, to detect if local cache goes
 248                 # out of date (due to update in other thread?)
 249                 if ( $wgLocalMessageCache !== false ) {
 250                         wfProfileIn( __METHOD__ . '-fromlocal' );
 251                         $hash = $this->mMemc->get( "$cacheKey-hash" );
 252                         if ( $hash ) {
 253                                 $success = $this->loadFromLocal( $hash, $code );
 254                                 if ( $success ) $where[] = 'got from local cache';
 255                         }
 256                         wfProfileOut( __METHOD__ . '-fromlocal' );
 257                 }
 258
 259                 # (2) memcache
 260                 # Fails if nothing in cache, or in the wrong version.
 261                 if ( !$success ) {
 262                         wfProfileIn( __METHOD__ . '-fromcache' );
 263                         $cache = $this->mMemc->get( $cacheKey );
 264                         $success = $this->setCache( $cache );
 265                         if ( $success ) {
 266                                 $where[] = 'got from global cache';
 267                                 $this->saveToCaches( $cache, $cacheKey, false );
 268                         }
 269                         wfProfileOut( __METHOD__ . '-fromcache' );
 270                 }
 271
 272
 273                 # (3)
 274                 # Nothing in caches... so we need create one and store it in caches
 275                 if ( !$success ) {
 276                         $where[] = 'cache is empty';
 277                         $this->lock($cacheKey);
 278                         wfProfileIn( __METHOD__ . '-load' );
 279                         $where[] = 'loading from database';
 280                         # We want to store messages of particular language here, not everything
 281                         # from mCache.
 282                         $cache = $this->loadFromDB( $code );
 283                         $success = $this->setCache( $cache );
 284                         wfProfileOut( __METHOD__ . '-load' );
 285                         if ( $success ) {
 286                                 $this->saveToCaches( $cache, $cacheKey );
 287                         }
 288                         $this->unlock($cacheKey);
 289                 }
 290
 291                 if ( !$success ) {
 292                         # Bad luck... this should not happen
 293                         $where[] = 'loading FAILED - cache is disabled';
 294                         $info = implode( ', ', $where );
 295                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 296                         $this->mDisable = true;
 297                         $this->mCache = false;
 298                 } else {
 299                         # All good, just record the success
 300                         $info = implode( ', ', $where );
 301                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 302                         if ( $code ) {
 303                                 $loaded[$code] = true;
 304                         } else {
 305                                 $loaded = true;
 306                         }
 307                 }
 308                 wfProfileOut( __METHOD__ );
 309                 return $success;
 310         }
 311
 312         /**
 313          * Loads cacheable messages from the database. Messages bigger than
 314          * $wgMaxMsgCacheEntrySize are assigned a special value, and are loaded
 315          * on-demand from the database later.
 316          *
 317          * @param $code Optional language code, see documenation of load().
 318          * @return Array: Loaded messages for storing in caches.
 319          */
 320         function loadFromDB( $code = false ) {
 321                 wfProfileIn( __METHOD__ );
 322                 global $wgMaxMsgCacheEntrySize, $wgContLanguageCode;
 323                 $dbr = wfGetDB( DB_SLAVE );
 324                 $cache = array();
 325
 326                 # Common conditions
 327                 $conds = array(
 328                         'page_is_redirect' => 0,
 329                         'page_namespace' => NS_MEDIAWIKI,
 330                 );
 331
 332                 if ( $code ) {
 333                         # Should $code be escaped?
 334                         # Is this fast enough. Should not matter if the filtering is done in the
 335                         # database or in code.
 336                         if ( $code !== $wgContLanguageCode ) {
 337                                 # Messages for particular language
 338                                 $conds[] = "page_title like '%%/$code'";
 339                         } else {
 340                                 # Effectively disallows use of '/' character in NS_MEDIAWIKI for uses
 341                                 # other than language code.
 342                                 $conds[] = "page_title not like '%%/%%'";
 343                         }
 344                 }
 345
 346                 # Conditions to fetch oversized pages to ignore them
 347                 $bigConds = $conds;
 348                 $bigConds[] = 'page_len > ' . intval( $wgMaxMsgCacheEntrySize );
 349
 350                 # Load titles for all oversized pages in the MediaWiki namespace
 351                 $res = $dbr->select( 'page', 'page_title', $bigConds, __METHOD__ );
 352                 while ( $row = $dbr->fetchObject( $res ) ) {
 353                         $cache[$row->page_title] = '!TOO BIG';
 354                 }
 355                 $dbr->freeResult( $res );
 356
 357                 # Conditions to load the remaining pages with their contents
 358                 $smallConds = $conds;
 359                 $smallConds[] = 'page_latest=rev_id';
 360                 $smallConds[] = 'rev_text_id=old_id';
 361                 $smallConds[] = 'page_len <= ' . intval( $wgMaxMsgCacheEntrySize );
 362
 363                 $res = $dbr->select( array( 'page', 'revision', 'text' ),
 364                         array( 'page_title', 'old_text', 'old_flags' ),
 365                         $smallConds, __METHOD__ );
 366
 367                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 368                         $cache[$row->page_title] = ' ' . Revision::getRevisionText( $row );
 369                 }
 370                 $dbr->freeResult( $res );
 371
 372                 $cache['VERSION'] = MSG_CACHE_VERSION;
 373                 wfProfileOut( __METHOD__ );
 374                 return $cache;
 375         }
 376
 377         /**
 378          * Updates cache as necessary when message page is changed
 379          *
 380          * @param $title String: name of the page changed.
 381          * @param $text Mixed: new contents of the page.
 382          */
 383         public function replace( $title, $text ) {
 384                 global $wgMaxMsgCacheEntrySize, $wgPerLanguageCaching;
 385
 386                 list( $message, $code ) = $this->figureMessage( $title );
 387
 388                 # TODO: Should we define the sidebar key name somewhere?
 389                 $sidebarKey = wfMemcKeyLang( 'sidebar' , $code );
 390
 391                 # Load only messages for affected language, if possible
 392                 if ( !$wgPerLanguageCaching ) $code = false;
 393                 $cacheKey = wfMemcKeyLang( $this->mMemcKey, $code );
 394
 395                 wfProfileIn( __METHOD__ );
 396                 $this->lock($cacheKey);
 397
 398                 $cache = $this->mMemc->get( $cacheKey );
 399                 if ( is_array( $cache ) ) {
 400                         if ( $text === false ) {
 401                                 # Article was deleted
 402                                 unset( $this->mCache[$title] );
 403                                 $this->mMemc->delete( "$this->mMemcKey:{$title}" );
 404                         } elseif ( strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
 405                                 $cache[$title] = $this->mCache[$title] = '!TOO BIG';
 406                                 $this->mMemc->set( "$this->mMemcKey:{$title}", ' '.$text, $this->mExpiry );
 407                         } else {
 408                                 $cache[$title] = $this->mCache[$title] = ' ' . $text;
 409                                 $this->mMemc->delete( "$this->mMemcKey:{$title}" );
 410                         }
 411
 412                         # Update per-request cache
 413                         $success = $this->setCache( $cache, $cacheKey );
 414                         if ( $success ) {
 415                                 # And then all caches
 416                                 $this->saveToCaches( $cache, $cacheKey );
 417                         }
 418                 }
 419                 $this->unlock($cacheKey);
 420
 421                 // Also delete cached sidebar... just in case it is affected
 422                 global $parserMemc;
 423                 $parserMemc->delete( $sidebarKey );
 424                 wfProfileOut( __METHOD__ );
 425         }
 426
 427         /**
 428          * Shortcut to update caches.
 429          *
 430          * @param $cache Array: cached messages with a version.
 431          * @param $cacheKey String: Identifier for the cache.
 432          * @param $memc Bool: Wether to update or not memcache.
 433          * @return False on somekind of error.
 434          */
 435         protected function saveToCaches( $cache, $cacheKey, $memc = true ) {
 436                 wfProfileIn( __METHOD__ );
 437                 global $wgLocalMessageCache, $wgLocalMessageCacheSerialized;
 438
 439                 $success = $this->mMemc->add( $cacheKey.'-status', "loading", MSG_LOAD_TIMEOUT );
 440                 if ( !$success ) return true; # Other process should be updating them now
 441
 442                 $i = 0;
 443                 if ( $memc ) {
 444                         # Save in memcached
 445                         # Keep trying if it fails, this is kind of important
 446
 447                         for ($i=0; $i<20 &&
 448                                                         !$this->mMemc->set( $cacheKey, $cache, $this->mExpiry );
 449                                         $i++ ) {
 450                                 usleep(mt_rand(500000,1500000));
 451                         }
 452                 }
 453
 454                 # Save to local cache
 455                 if ( $wgLocalMessageCache !== false ) {
 456                         $serialized = serialize( $cache );
 457                         $hash = md5( $serialized );
 458                         $this->mMemc->set( "$cacheKey-hash", $hash, $this->mExpiry );
 459                         if ($wgLocalMessageCacheSerialized) {
 460                                 $this->saveToLocal( $serialized, $hash, $code );
 461                         } else {
 462                                 $this->saveToScript( $cache, $hash, $code );
 463                         }
 464                 }
 465
 466                 if ( $i == 20 ) {
 467                         $this->mMemc->set( $cacheKey.'-status', 'error', 60*5 );
 468                         wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 469                         $success = false;
 470                 } else {
 471                         $this->mMemc->delete( $cacheKey.'-status' );
 472                         $success = true;
 473                 }
 474                 wfProfileOut( __METHOD__ );
 475                 return $success;
 476         }
 477
 478         /**
 479          * Returns success
 480          * Represents a write lock on the messages key
 481          */
 482         function lock($key) {
 483                 if ( !$this->mUseCache ) {
 484                         return true;
 485                 }
 486
 487                 $lockKey = $key . 'lock';
 488                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 489                         sleep(1);
 490                 }
 491
 492                 return $i >= MSG_WAIT_TIMEOUT;
 493         }
 494
 495         function unlock($key) {
 496                 if ( !$this->mUseCache ) {
 497                         return;
 498                 }
 499
 500                 $lockKey = $key . 'lock';
 501                 $this->mMemc->delete( $lockKey );
 502         }
 503
 504         /**
 505          * Get a message from either the content language or the user language.
 506          *
 507          * @param string $key The message cache key
 508          * @param bool $useDB Get the message from the DB, false to use only the localisation
 509          * @param string $langcode Code of the language to get the message for, if
 510          *                         it is a valid code create a language for that
 511          *                         language, if it is a string but not a valid code
 512          *                         then make a basic language object, if it is a
 513          *                         false boolean then use the current users
 514          *                         language (as a fallback for the old parameter
 515          *                         functionality), or if it is a true boolean then
 516          *                         use the wikis content language (also as a
 517          *                         fallback).
 518          * @param bool $isFullKey Specifies whether $key is a two part key "lang/msg".
 519          */
 520         function get( $key, $useDB = true, $langcode = true, $isFullKey = false ) {
 521                 global $wgContLanguageCode, $wgContLang, $wgLang;
 522
 523                 # Identify which language to get or create a language object for.
 524                 if( $langcode === $wgContLang->getCode() || $langcode === true ) {
 525                         # $langcode is the language code of the wikis content language object.
 526                         # or it is a boolean and value is true
 527                         $lang =& $wgContLang;
 528                 } elseif( $langcode === $wgLang->getCode() || $langcode === false ) {
 529                         # $langcode is the language code of user language object.
 530                         # or it was a boolean and value is false
 531                         $lang =& $wgLang;
 532                 } else {
 533                         $validCodes = array_keys( Language::getLanguageNames() );
 534                         if( in_array( $langcode, $validCodes ) ) {
 535                                 # $langcode corresponds to a valid language.
 536                                 $lang = Language::factory( $langcode );
 537                         } else {
 538                                 # $langcode is a string, but not a valid language code; use content language.
 539                                 $lang =& $wgContLang;
 540                                 wfDebug( 'Invalid language code passed to MessageCache::get, falling back to content language.' );
 541                         }
 542                 }
 543
 544                 $langcode = $lang->getCode();
 545
 546                 # If uninitialised, someone is trying to call this halfway through Setup.php
 547                 if( !$this->mInitialised ) {
 548                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 549                 }
 550
 551                 $message = false;
 552
 553                 # Normalise title-case input
 554                 $lckey = $wgContLang->lcfirst( $key );
 555                 $lckey = str_replace( ' ', '_', $lckey );
 556
 557                 # Try the MediaWiki namespace
 558                 if( !$this->mDisable && $useDB ) {
 559                         $title = $wgContLang->ucfirst( $lckey );
 560                         if(!$isFullKey && ($langcode != $wgContLanguageCode) ) {
 561                                 $title .= '/' . $langcode;
 562                         }
 563                         $message = $this->getMsgFromNamespace( $title, $langcode );
 564                 }
 565
 566                 # Try the extension array
 567                 if ( $message === false && isset( $this->mExtensionMessages[$langcode][$lckey] ) ) {
 568                         $message = $this->mExtensionMessages[$langcode][$lckey];
 569                 }
 570                 if ( $message === false && isset( $this->mExtensionMessages['en'][$lckey] ) ) {
 571                         $message = $this->mExtensionMessages['en'][$lckey];
 572                 }
 573
 574                 # Try the array in the language object
 575                 if ( $message === false ) {
 576                         $message = $lang->getMessage( $lckey );
 577                         if ( is_null( $message ) ) {
 578                                 $message = false;
 579                         }
 580                 }
 581
 582                 # Try the array of another language
 583                 $pos = strrpos( $lckey, '/' );
 584                 if( $message === false && $pos !== false) {
 585                         $mkey = substr( $lckey, 0, $pos );
 586                         $code = substr( $lckey, $pos+1 );
 587                         if ( $code ) {
 588                                 $validCodes = array_keys( Language::getLanguageNames() );
 589                                 if ( in_array( $code, $validCodes ) ) {
 590                                         $message = Language::getMessageFor( $mkey, $code );
 591                                         if ( is_null( $message ) ) {
 592                                                 $message = false;
 593                                         }
 594                                 } else {
 595                                         wfDebug( __METHOD__ . ": Invalid code $code for $mkey/$code, not trying messages array\n" );
 596                                 }
 597                         }
 598                 }
 599
 600                 # Is this a custom message? Try the default language in the db...
 601                 if( ($message === false || $message === '-' ) &&
 602                         !$this->mDisable && $useDB &&
 603                         !$isFullKey && ($langcode != $wgContLanguageCode) ) {
 604                         $message = $this->getMsgFromNamespace( $wgContLang->ucfirst( $lckey ), $wgContLanguageCode );
 605                 }
 606
 607                 # Final fallback
 608                 if( $message === false ) {
 609                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 610                 }
 611                 return $message;
 612         }
 613
 614         /**
 615          * Get a message from the MediaWiki namespace, with caching. The key must
 616          * first be converted to two-part lang/msg form if necessary.
 617          *
 618          * @param $title String: Message cache key with initial uppercase letter.
 619          * @param $code String: code denoting the language to try.
 620          */
 621         function getMsgFromNamespace( $title, $code ) {
 622                 $message = false;
 623                 $type = false;
 624
 625                 if ( $this->mUseCache ) {
 626                         if ( !isset($this->mCache[$title]) ) {
 627                                 # Delay loading as far as possible, and only load messages for requested
 628                                 # language.
 629                                 $this->load( $code );
 630                         }
 631                         if (isset( $this->mCache[$title] ) ) {
 632                                 $entry = $this->mCache[$title];
 633                                 $type = substr( $entry, 0, 1 );
 634                                 if ( $type == ' ' ) {
 635                                         return substr( $entry, 1 );
 636                                 }
 637                         }
 638                 }
 639
 640                 # Call message hooks, in case they are defined
 641                 wfRunHooks('MessagesPreLoad', array( $title, &$message ) );
 642                 if ( $message !== false ) {
 643                         return $message;
 644                 }
 645
 646                 # If there is no cache entry and no placeholder, it doesn't exist
 647                 if ( $type != '!' && $message === false ) {
 648                         return false;
 649                 }
 650
 651                 $memcKey = $this->mMemcKey . ':' . $title;
 652
 653                 # Try the individual message cache
 654                 if ( $this->mUseCache ) {
 655                         $entry = $this->mMemc->get( $memcKey );
 656                         if ( $entry ) {
 657                                 $type = substr( $entry, 0, 1 );
 658
 659                                 if ( $type == ' ' ) {
 660                                         # Ok!
 661                                         $message = substr( $entry, 1 );
 662                                         $this->mCache[$title] = $entry;
 663                                         return $message;
 664                                 } elseif ( $entry == '!NONEXISTENT' ) {
 665                                         return false;
 666                                 } else {
 667                                         # Corrupt/obsolete entry, delete it
 668                                         $this->mMemc->delete( $memcKey );
 669                                 }
 670
 671                         }
 672                 }
 673
 674                 # Try loading it from the DB
 675                 $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 676                 if( $revision ) {
 677                         $message = $revision->getText();
 678                         if ($this->mUseCache) {
 679                                 $this->mCache[$title] = ' ' . $message;
 680                                 $this->mMemc->set( $memcKey, $message, $this->mExpiry );
 681                         }
 682                 } else {
 683                         # Negative caching
 684                         # Use some special text instead of false, because false gets converted to '' somewhere
 685                         $this->mMemc->set( $memcKey, '!NONEXISTENT', $this->mExpiry );
 686                         $this->mCache[$title] = false;
 687                 }
 688                 return $message;
 689         }
 690
 691         function transform( $message, $interface = false ) {
 692                 global $wgParser;
 693                 if ( !$this->mParser && isset( $wgParser ) ) {
 694                         # Do some initialisation so that we don't have to do it twice
 695                         $wgParser->firstCallInit();
 696                         # Clone it and store it
 697                         $this->mParser = clone $wgParser;
 698                 }
 699                 if ( $this->mParser ) {
 700                         if( strpos( $message, '{{' ) !== false ) {
 701                                 $popts = $this->getParserOptions();
 702                                 $popts->setInterfaceMessage( $interface );
 703                                 $message = $this->mParser->transformMsg( $message, $popts );
 704                         }
 705                 }
 706                 return $message;
 707         }
 708
 709         function disable() { $this->mDisable = true; }
 710         function enable() { $this->mDisable = false; }
 711
 712         /** @deprecated */
 713         function disableTransform(){
 714                 wfDeprecated( __METHOD__ );
 715         }
 716         function enableTransform() {
 717                 wfDeprecated( __METHOD__ );
 718         }
 719         function setTransform( $x ) {
 720                 wfDeprecated( __METHOD__ );
 721         }
 722         function getTransform() {
 723                 wfDeprecated( __METHOD__ );
 724                 return false;
 725         }
 726
 727         /**
 728          * Add a message to the cache
 729          *
 730          * @param mixed $key
 731          * @param mixed $value
 732          * @param string $lang The messages language, English by default
 733          */
 734         function addMessage( $key, $value, $lang = 'en' ) {
 735                 $this->mExtensionMessages[$lang][$key] = $value;
 736         }
 737
 738         /**
 739          * Add an associative array of message to the cache
 740          *
 741          * @param array $messages An associative array of key => values to be added
 742          * @param string $lang The messages language, English by default
 743          */
 744         function addMessages( $messages, $lang = 'en' ) {
 745                 wfProfileIn( __METHOD__ );
 746                 if ( !is_array( $messages ) ) {
 747                         throw new MWException( __METHOD__.': Invalid message array' );
 748                 }
 749                 if ( isset( $this->mExtensionMessages[$lang] ) ) {
 750                         $this->mExtensionMessages[$lang] = $messages + $this->mExtensionMessages[$lang];
 751                 } else {
 752                         $this->mExtensionMessages[$lang] = $messages;
 753                 }
 754                 wfProfileOut( __METHOD__ );
 755         }
 756
 757         /**
 758          * Add a 2-D array of messages by lang. Useful for extensions.
 759          *
 760          * @param array $messages The array to be added
 761          */
 762         function addMessagesByLang( $messages ) {
 763                 wfProfileIn( __METHOD__ );
 764                 foreach ( $messages as $key => $value ) {
 765                         $this->addMessages( $value, $key );
 766                 }
 767                 wfProfileOut( __METHOD__ );
 768         }
 769
 770         /**
 771          * Get the extension messages for a specific language. Only English, interface
 772          * and content language are guaranteed to be loaded.
 773          *
 774          * @param string $lang The messages language, English by default
 775          */
 776         function getExtensionMessagesFor( $lang = 'en' ) {
 777                 wfProfileIn( __METHOD__ );
 778                 $messages = array();
 779                 if ( isset( $this->mExtensionMessages[$lang] ) ) {
 780                         $messages = $this->mExtensionMessages[$lang];
 781                 }
 782                 if ( $lang != 'en' ) {
 783                         $messages = $messages + $this->mExtensionMessages['en'];
 784                 }
 785                 wfProfileOut( __METHOD__ );
 786                 return $messages;
 787         }
 788
 789         /**
 790          * Clear all stored messages. Mainly used after a mass rebuild.
 791          */
 792         function clear() {
 793                 global $wgLocalMessageCache;
 794                 if( $this->mUseCache ) {
 795                         # Global cache
 796                         $this->mMemc->delete( $this->mMemcKey );
 797                         # Invalidate all local caches
 798                         $this->mMemc->delete( "{$this->mMemcKey}-hash" );
 799                 }
 800         }
 801
 802         function loadAllMessages() {
 803                 global $wgExtensionMessagesFiles;
 804                 if ( $this->mAllMessagesLoaded ) {
 805                         return;
 806                 }
 807                 $this->mAllMessagesLoaded = true;
 808
 809                 # Some extensions will load their messages when you load their class file
 810                 wfLoadAllExtensions();
 811                 # Others will respond to this hook
 812                 wfRunHooks( 'LoadAllMessages' );
 813                 # Some register their messages in $wgExtensionMessagesFiles
 814                 foreach ( $wgExtensionMessagesFiles as $name => $file ) {
 815                         wfLoadExtensionMessages( $name );
 816                 }
 817                 # Still others will respond to neither, they are EVIL. We sometimes need to know!
 818         }
 819
 820         /**
 821          * Load messages from a given file
 822          *
 823          * @param string $filename Filename of file to load.
 824          * @param string $langcode Language to load messages for, or false for
 825      *                         default behvaiour (en, content language and user
 826      *                         language).
 827          */
 828         function loadMessagesFile( $filename, $langcode = false ) {
 829                 global $wgLang, $wgContLang;
 830                 $messages = $magicWords = false;
 831                 require( $filename );
 832
 833                 $validCodes = Language::getLanguageNames();
 834                 if( is_string( $langcode ) && array_key_exists( $langcode, $validCodes ) ) {
 835                         # Load messages for given language code.
 836                         $this->processMessagesArray( $messages, $langcode );
 837                 } elseif( is_string( $langcode ) && !array_key_exists( $langcode, $validCodes ) ) {
 838                         wfDebug( "Invalid language '$langcode' code passed to MessageCache::loadMessagesFile()" );
 839                 } else {
 840                         # Load only languages that are usually used, and merge all
 841                         # fallbacks, except English.
 842                         $langs = array_unique( array( 'en', $wgContLang->getCode(), $wgLang->getCode() ) );
 843                         foreach( $langs as $code ) {
 844                                 $this->processMessagesArray( $messages, $code );
 845                         }
 846                 }
 847
 848                 if ( $magicWords !== false ) {
 849                         global $wgContLang;
 850                         $wgContLang->addMagicWordsByLang( $magicWords );
 851                 }
 852         }
 853
 854         /**
 855          * Process an array of messages, loading it into the message cache.
 856          *
 857          * @param array $messages Messages array.
 858          * @param string $langcode Language code to process.
 859          */
 860         function processMessagesArray( $messages, $langcode ) {
 861                 $fallbackCode = $langcode;
 862                 $mergedMessages = array();
 863                 do {
 864                         if ( isset($messages[$fallbackCode]) ) {
 865                                 $mergedMessages += $messages[$fallbackCode];
 866                         }
 867                         $fallbackCode = Language::getFallbackfor( $fallbackCode );
 868                 } while( $fallbackCode && $fallbackCode !== 'en' );
 869
 870                 if ( !empty($mergedMessages) )
 871                         $this->addMessages( $mergedMessages, $langcode );
 872         }
 873
 874         public function figureMessage( $key ) {
 875                 global $wgContLanguageCode;
 876                 $pieces = explode('/', $key, 2);
 877
 878                 $key = $pieces[0];
 879
 880                 # Language the user is translating to
 881                 $langCode = isset($pieces[1]) ? $pieces[1] : $wgContLanguageCode;
 882                 return array( $key, $langCode );
 883         }
 884
 885 }