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         /**
  22          * Process local cache of loaded messages that are defined in
  23          * MediaWiki namespace. First array level is a language code,
  24          * second level is message key and the values are either message
  25          * content prefixed with space, or !NONEXISTENT for negative
  26          * caching.
  27          */
  28         protected $mCache;
  29
  30         // Should  mean that database cannot be used, but check
  31         protected $mDisable;
  32
  33         /// Lifetime for cache, used by object caching
  34         protected $mExpiry;
  35
  36         /**
  37          * Message cache has it's own parser which it uses to transform
  38          * messages.
  39          */
  40         protected $mParserOptions, $mParser;
  41
  42         /// Variable for tracking which variables are already loaded
  43         protected $mLoadedLanguages = array();
  44
  45         /**
  46          * Used for automatic detection of most used messages.
  47          */
  48         protected $mRequestedMessages = array();
  49
  50         /**
  51          * How long the message request counts are stored. Longer period gives
  52          * better sample, but also takes longer to adapt changes. The counts
  53          * are aggregrated per day, regardless of the value of this variable.
  54          */
  55         protected static $mAdaptiveDataAge = 604800; // Is 7*24*3600
  56
  57         /**
  58          * Filter the tail of less used messages that are requested more seldom
  59          * than this factor times the number of request of most requested message.
  60          * These messages are not loaded in the default set, but are still cached
  61          * individually on demand with the normal cache expiry time.
  62          */
  63         protected static $mAdaptiveInclusionThreshold = 0.05;
  64
  65         /**
  66          * Singleton instance
  67          */
  68         private static $instance;
  69
  70         /**
  71          * Get the signleton instance of this class
  72          *
  73          * @since 1.18
  74          * @return MessageCache object
  75          */
  76         public static function singleton() {
  77                 if ( is_null( self::$instance ) ) {
  78                         global $wgUseDatabaseMessages, $wgMsgCacheExpiry;
  79                         self::$instance = new self( wfGetMessageCacheStorage(), $wgUseDatabaseMessages, $wgMsgCacheExpiry );
  80                 }
  81                 return self::$instance;
  82         }
  83
  84         /**
  85          * Destroy the signleton instance
  86          *
  87          * @since 1.18
  88          */
  89         public static function destroyInstance() {
  90                 self::$instance = null;
  91         }
  92
  93         function __construct( $memCached, $useDB, $expiry ) {
  94                 if ( !$memCached ) {
  95                         $memCached = wfGetCache( CACHE_NONE );
  96                 }
  97
  98                 $this->mMemc = $memCached;
  99                 $this->mDisable = !$useDB;
 100                 $this->mExpiry = $expiry;
 101         }
 102
 103
 104         /**
 105          * ParserOptions is lazy initialised.
 106          */
 107         function getParserOptions() {
 108                 if ( !$this->mParserOptions ) {
 109                         $this->mParserOptions = new ParserOptions;
 110                 }
 111                 return $this->mParserOptions;
 112         }
 113
 114         /**
 115          * Try to load the cache from a local file.
 116          * Actual format of the file depends on the $wgLocalMessageCacheSerialized
 117          * setting.
 118          *
 119          * @param $hash String: the hash of contents, to check validity.
 120          * @param $code Mixed: Optional language code, see documenation of load().
 121          * @return false on failure.
 122          */
 123         function loadFromLocal( $hash, $code ) {
 124                 global $wgCacheDirectory, $wgLocalMessageCacheSerialized;
 125
 126                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 127
 128                 # Check file existence
 129                 wfSuppressWarnings();
 130                 $file = fopen( $filename, 'r' );
 131                 wfRestoreWarnings();
 132                 if ( !$file ) {
 133                         return false; // No cache file
 134                 }
 135
 136                 if ( $wgLocalMessageCacheSerialized ) {
 137                         // Check to see if the file has the hash specified
 138                         $localHash = fread( $file, 32 );
 139                         if ( $hash === $localHash ) {
 140                                 // All good, get the rest of it
 141                                 $serialized = '';
 142                                 while ( !feof( $file ) ) {
 143                                         $serialized .= fread( $file, 100000 );
 144                                 }
 145                                 fclose( $file );
 146                                 return $this->setCache( unserialize( $serialized ), $code );
 147                         } else {
 148                                 fclose( $file );
 149                                 return false; // Wrong hash
 150                         }
 151                 } else {
 152                         $localHash=substr(fread($file,40),8);
 153                         fclose($file);
 154                         if ($hash!=$localHash) {
 155                                 return false; // Wrong hash
 156                         }
 157
 158                         # Require overwrites the member variable or just shadows it?
 159                         require( $filename );
 160                         return $this->setCache( $this->mCache, $code );
 161                 }
 162         }
 163
 164         /**
 165          * Save the cache to a local file.
 166          */
 167         function saveToLocal( $serialized, $hash, $code ) {
 168                 global $wgCacheDirectory;
 169
 170                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 171                 wfMkdirParents( $wgCacheDirectory ); // might fail
 172
 173                 wfSuppressWarnings();
 174                 $file = fopen( $filename, 'w' );
 175                 wfRestoreWarnings();
 176
 177                 if ( !$file ) {
 178                         wfDebug( "Unable to open local cache file for writing\n" );
 179                         return;
 180                 }
 181
 182                 fwrite( $file, $hash . $serialized );
 183                 fclose( $file );
 184                 @chmod( $filename, 0666 );
 185         }
 186
 187         function saveToScript( $array, $hash, $code ) {
 188                 global $wgCacheDirectory;
 189
 190                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 191                 $tempFilename = $filename . '.tmp';
 192                 wfMkdirParents( $wgCacheDirectory ); // might fail
 193
 194                 wfSuppressWarnings();
 195                 $file = fopen( $tempFilename, 'w');
 196                 wfRestoreWarnings();
 197
 198                 if ( !$file ) {
 199                         wfDebug( "Unable to open local cache file for writing\n" );
 200                         return;
 201                 }
 202
 203                 fwrite($file,"<?php\n//$hash\n\n \$this->mCache = array(");
 204
 205                 foreach ( $array as $key => $message ) {
 206                         $key = $this->escapeForScript($key);
 207                         $message = $this->escapeForScript($message);
 208                         fwrite($file, "'$key' => '$message',\n");
 209                 }
 210
 211                 fwrite($file,");\n?>");
 212                 fclose($file);
 213                 rename($tempFilename, $filename);
 214         }
 215
 216         function escapeForScript($string) {
 217                 $string = str_replace( '\\', '\\\\', $string );
 218                 $string = str_replace( '\'', '\\\'', $string );
 219                 return $string;
 220         }
 221
 222         /**
 223          * Set the cache to $cache, if it is valid. Otherwise set the cache to false.
 224          */
 225         function setCache( $cache, $code ) {
 226                 if ( isset( $cache['VERSION'] ) && $cache['VERSION'] == MSG_CACHE_VERSION ) {
 227                         $this->mCache[$code] = $cache;
 228                         return true;
 229                 } else {
 230                         return false;
 231                 }
 232         }
 233
 234         /**
 235          * Loads messages from caches or from database in this order:
 236          * (1) local message cache (if $wgUseLocalMessageCache is enabled)
 237          * (2) memcached
 238          * (3) from the database.
 239          *
 240          * When succesfully loading from (2) or (3), all higher level caches are
 241          * updated for the newest version.
 242          *
 243          * Nothing is loaded if member variable mDisable is true, either manually
 244          * set by calling code or if message loading fails (is this possible?).
 245          *
 246          * Returns true if cache is already populated or it was succesfully populated,
 247          * or false if populating empty cache fails. Also returns true if MessageCache
 248          * is disabled.
 249          *
 250          * @param $code String: language to which load messages
 251          */
 252         function load( $code = false ) {
 253                 global $wgUseLocalMessageCache;
 254
 255                 if( !is_string( $code ) ) {
 256                         # This isn't really nice, so at least make a note about it and try to
 257                         # fall back
 258                         wfDebug( __METHOD__ . " called without providing a language code\n" );
 259                         $code = 'en';
 260                 }
 261
 262                 # Don't do double loading...
 263                 if ( isset($this->mLoadedLanguages[$code]) ) return true;
 264
 265                 # 8 lines of code just to say (once) that message cache is disabled
 266                 if ( $this->mDisable ) {
 267                         static $shownDisabled = false;
 268                         if ( !$shownDisabled ) {
 269                                 wfDebug( __METHOD__ . ": disabled\n" );
 270                                 $shownDisabled = true;
 271                         }
 272                         return true;
 273                 }
 274
 275                 # Loading code starts
 276                 wfProfileIn( __METHOD__ );
 277                 $success = false; # Keep track of success
 278                 $where = array(); # Debug info, delayed to avoid spamming debug log too much
 279                 $cacheKey = wfMemcKey( 'messages', $code ); # Key in memc for messages
 280
 281
 282                 # (1) local cache
 283                 # Hash of the contents is stored in memcache, to detect if local cache goes
 284                 # out of date (due to update in other thread?)
 285                 if ( $wgUseLocalMessageCache ) {
 286                         wfProfileIn( __METHOD__ . '-fromlocal' );
 287
 288                         $hash = $this->mMemc->get( wfMemcKey( 'messages', $code, 'hash' ) );
 289                         if ( $hash ) {
 290                                 $success = $this->loadFromLocal( $hash, $code );
 291                                 if ( $success ) $where[] = 'got from local cache';
 292                         }
 293                         wfProfileOut( __METHOD__ . '-fromlocal' );
 294                 }
 295
 296                 # (2) memcache
 297                 # Fails if nothing in cache, or in the wrong version.
 298                 if ( !$success ) {
 299                         wfProfileIn( __METHOD__ . '-fromcache' );
 300                         $cache = $this->mMemc->get( $cacheKey );
 301                         $success = $this->setCache( $cache, $code );
 302                         if ( $success ) {
 303                                 $where[] = 'got from global cache';
 304                                 $this->saveToCaches( $cache, false, $code );
 305                         }
 306                         wfProfileOut( __METHOD__ . '-fromcache' );
 307                 }
 308
 309
 310                 # (3)
 311                 # Nothing in caches... so we need create one and store it in caches
 312                 if ( !$success ) {
 313                         $where[] = 'cache is empty';
 314                         $where[] = 'loading from database';
 315
 316                         $this->lock($cacheKey);
 317
 318                         # Limit the concurrency of loadFromDB to a single process
 319                         # This prevents the site from going down when the cache expires
 320                         $statusKey = wfMemcKey( 'messages', $code, 'status' );
 321                         $success = $this->mMemc->add( $statusKey, 'loading', MSG_LOAD_TIMEOUT );
 322                         if ( $success ) {
 323                                 $cache = $this->loadFromDB( $code );
 324                                 $success = $this->setCache( $cache, $code );
 325                         }
 326                         if ( $success ) {
 327                                 $success = $this->saveToCaches( $cache, true, $code );
 328                                 if ( $success ) {
 329                                         $this->mMemc->delete( $statusKey );
 330                                 } else {
 331                                         $this->mMemc->set( $statusKey, 'error', 60*5 );
 332                                         wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 333                                 }
 334                         }
 335                         $this->unlock($cacheKey);
 336                 }
 337
 338                 if ( !$success ) {
 339                         # Bad luck... this should not happen
 340                         $where[] = 'loading FAILED - cache is disabled';
 341                         $info = implode( ', ', $where );
 342                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 343                         $this->mDisable = true;
 344                         $this->mCache = false;
 345                 } else {
 346                         # All good, just record the success
 347                         $info = implode( ', ', $where );
 348                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 349                         $this->mLoadedLanguages[$code] = true;
 350                 }
 351                 wfProfileOut( __METHOD__ );
 352                 return $success;
 353         }
 354
 355         /**
 356          * Loads cacheable messages from the database. Messages bigger than
 357          * $wgMaxMsgCacheEntrySize are assigned a special value, and are loaded
 358          * on-demand from the database later.
 359          *
 360          * @param $code \string Language code.
 361          * @return \array Loaded messages for storing in caches.
 362          */
 363         function loadFromDB( $code ) {
 364                 wfProfileIn( __METHOD__ );
 365                 global $wgMaxMsgCacheEntrySize, $wgLanguageCode, $wgAdaptiveMessageCache;
 366                 $dbr = wfGetDB( DB_SLAVE );
 367                 $cache = array();
 368
 369                 # Common conditions
 370                 $conds = array(
 371                         'page_is_redirect' => 0,
 372                         'page_namespace' => NS_MEDIAWIKI,
 373                 );
 374
 375                 $mostused = array();
 376                 if ( $wgAdaptiveMessageCache ) {
 377                         $mostused = $this->getMostUsedMessages();
 378                         if ( $code !== $wgLanguageCode ) {
 379                                 foreach ( $mostused as $key => $value ) $mostused[$key] = "$value/$code";
 380                         }
 381                 }
 382
 383                 if ( count( $mostused ) ) {
 384                         $conds['page_title'] = $mostused;
 385                 } elseif ( $code !== $wgLanguageCode ) {
 386                         $conds[] = 'page_title' . $dbr->buildLike( $dbr->anyString(), "/$code" );
 387                 } else {
 388                         # Effectively disallows use of '/' character in NS_MEDIAWIKI for uses
 389                         # other than language code.
 390                         $conds[] = 'page_title NOT' . $dbr->buildLike( $dbr->anyString(), '/', $dbr->anyString() );
 391                 }
 392
 393                 # Conditions to fetch oversized pages to ignore them
 394                 $bigConds = $conds;
 395                 $bigConds[] = 'page_len > ' . intval( $wgMaxMsgCacheEntrySize );
 396
 397                 # Load titles for all oversized pages in the MediaWiki namespace
 398                 $res = $dbr->select( 'page', 'page_title', $bigConds, __METHOD__ . "($code)-big" );
 399                 foreach ( $res as $row ) {
 400                         $cache[$row->page_title] = '!TOO BIG';
 401                 }
 402
 403                 # Conditions to load the remaining pages with their contents
 404                 $smallConds = $conds;
 405                 $smallConds[] = 'page_latest=rev_id';
 406                 $smallConds[] = 'rev_text_id=old_id';
 407                 $smallConds[] = 'page_len <= ' . intval( $wgMaxMsgCacheEntrySize );
 408
 409                 $res = $dbr->select( array( 'page', 'revision', 'text' ),
 410                         array( 'page_title', 'old_text', 'old_flags' ),
 411                         $smallConds, __METHOD__ . "($code)-small" );
 412
 413                 foreach ( $res as $row ) {
 414                         $cache[$row->page_title] = ' ' . Revision::getRevisionText( $row );
 415                 }
 416
 417                 foreach ( $mostused as $key ) {
 418                         if ( !isset( $cache[$key] ) ) {
 419                                 $cache[$key] = '!NONEXISTENT';
 420                         }
 421                 }
 422
 423                 $cache['VERSION'] = MSG_CACHE_VERSION;
 424                 wfProfileOut( __METHOD__ );
 425                 return $cache;
 426         }
 427
 428         /**
 429          * Updates cache as necessary when message page is changed
 430          *
 431          * @param $title String: name of the page changed.
 432          * @param $text Mixed: new contents of the page.
 433          */
 434         public function replace( $title, $text ) {
 435                 global $wgMaxMsgCacheEntrySize;
 436                 wfProfileIn( __METHOD__ );
 437
 438                 if ( $this->mDisable ) {
 439                         return;
 440                 }
 441
 442                 list( $msg, $code ) = $this->figureMessage( $title );
 443
 444                 $cacheKey = wfMemcKey( 'messages', $code );
 445                 $this->load( $code );
 446                 $this->lock( $cacheKey );
 447
 448                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 449
 450                 if ( $text === false ) {
 451                         # Article was deleted
 452                         $this->mCache[$code][$title] = '!NONEXISTENT';
 453                         $this->mMemc->delete( $titleKey );
 454
 455                 } elseif ( strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
 456                         # Check for size
 457                         $this->mCache[$code][$title] = '!TOO BIG';
 458                         $this->mMemc->set( $titleKey, ' ' . $text, $this->mExpiry );
 459
 460                 } else {
 461                         $this->mCache[$code][$title] = ' ' . $text;
 462                         $this->mMemc->delete( $titleKey );
 463                 }
 464
 465                 # Update caches
 466                 $this->saveToCaches( $this->mCache[$code], true, $code );
 467                 $this->unlock( $cacheKey );
 468
 469                 // Also delete cached sidebar... just in case it is affected
 470                 $codes = array( $code );
 471                 if ( $code === 'en'  ) {
 472                         // Delete all sidebars, like for example on action=purge on the
 473                         // sidebar messages
 474                         $codes = array_keys( Language::getLanguageNames() );
 475                 }
 476
 477                 global $parserMemc;
 478                 foreach ( $codes as $code ) {
 479                         $sidebarKey = wfMemcKey( 'sidebar', $code );
 480                         $parserMemc->delete( $sidebarKey );
 481                 }
 482
 483                 // Update the message in the message blob store
 484                 global $wgContLang;
 485                 MessageBlobStore::updateMessage( $wgContLang->lcfirst( $msg ) );
 486
 487                 wfRunHooks( "MessageCacheReplace", array( $title, $text ) );
 488
 489                 wfProfileOut( __METHOD__ );
 490         }
 491
 492         /**
 493          * Shortcut to update caches.
 494          *
 495          * @param $cache Array: cached messages with a version.
 496          * @param $memc Bool: Wether to update or not memcache.
 497          * @param $code String: Language code.
 498          * @return False on somekind of error.
 499          */
 500         protected function saveToCaches( $cache, $memc = true, $code = false ) {
 501                 wfProfileIn( __METHOD__ );
 502                 global $wgUseLocalMessageCache, $wgLocalMessageCacheSerialized;
 503
 504                 $cacheKey = wfMemcKey( 'messages', $code );
 505
 506                 if ( $memc ) {
 507                         $success = $this->mMemc->set( $cacheKey, $cache, $this->mExpiry );
 508                 } else {
 509                         $success = true;
 510                 }
 511
 512                 # Save to local cache
 513                 if ( $wgUseLocalMessageCache ) {
 514                         $serialized = serialize( $cache );
 515                         $hash = md5( $serialized );
 516                         $this->mMemc->set( wfMemcKey( 'messages', $code, 'hash' ), $hash, $this->mExpiry );
 517                         if ($wgLocalMessageCacheSerialized) {
 518                                 $this->saveToLocal( $serialized, $hash, $code );
 519                         } else {
 520                                 $this->saveToScript( $cache, $hash, $code );
 521                         }
 522                 }
 523
 524                 wfProfileOut( __METHOD__ );
 525                 return $success;
 526         }
 527
 528         /**
 529          * Represents a write lock on the messages key
 530          *
 531          * @return Boolean: success
 532          */
 533         function lock($key) {
 534                 $lockKey = $key . ':lock';
 535                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 536                         sleep(1);
 537                 }
 538
 539                 return $i >= MSG_WAIT_TIMEOUT;
 540         }
 541
 542         function unlock($key) {
 543                 $lockKey = $key . ':lock';
 544                 $this->mMemc->delete( $lockKey );
 545         }
 546
 547         /**
 548          * Get a message from either the content language or the user language.
 549          *
 550          * @param $key String: the message cache key
 551          * @param $useDB Boolean: get the message from the DB, false to use only
 552          *               the localisation
 553          * @param $langcode String: code of the language to get the message for, if
 554          *                  it is a valid code create a language for that language,
 555          *                  if it is a string but not a valid code then make a basic
 556          *                  language object, if it is a false boolean then use the
 557          *                  current users language (as a fallback for the old
 558          *                  parameter functionality), or if it is a true boolean
 559          *                  then use the wikis content language (also as a
 560          *                  fallback).
 561          * @param $isFullKey Boolean: specifies whether $key is a two part key
 562          *                   "msg/lang".
 563          */
 564         function get( $key, $useDB = true, $langcode = true, $isFullKey = false ) {
 565                 global $wgLanguageCode, $wgContLang;
 566
 567                 if ( !is_string( $key ) ) {
 568                         throw new MWException( "Non-string key given" );
 569                 }
 570
 571                 if ( strval( $key ) === '' ) {
 572                         # Shortcut: the empty key is always missing
 573                         return false;
 574                 }
 575
 576                 $lang = wfGetLangObj( $langcode );
 577                 if ( !$lang ) {
 578                         throw new MWException( "Bad lang code $langcode given" );
 579                 }
 580
 581                 // Don't change getPreferredVariant() to getCode() / mCode, for
 582                 // more details, see the comment in Language::getMessage().
 583                 $langcode = $lang->getPreferredVariant();
 584
 585                 $message = false;
 586
 587                 # Normalise title-case input (with some inlining)
 588                 $lckey = str_replace( ' ', '_', $key );
 589                 if ( ord( $key ) < 128 ) {
 590                         $lckey[0] = strtolower( $lckey[0] );
 591                         $uckey = ucfirst( $lckey );
 592                 } else {
 593                         $lckey = $wgContLang->lcfirst( $lckey );
 594                         $uckey = $wgContLang->ucfirst( $lckey );
 595                 }
 596
 597                 /* Record each message request, but only once per request.
 598                  * This information is not used unless $wgAdaptiveMessageCache
 599                  * is enabled. */
 600                 $this->mRequestedMessages[$uckey] = true;
 601
 602                 # Try the MediaWiki namespace
 603                 if( !$this->mDisable && $useDB ) {
 604                         $title = $uckey;
 605                         if(!$isFullKey && ( $langcode != $wgLanguageCode ) ) {
 606                                 $title .= '/' . $langcode;
 607                         }
 608                         $message = $this->getMsgFromNamespace( $title, $langcode );
 609                 }
 610
 611                 # Try the array in the language object
 612                 if ( $message === false ) {
 613                         $message = $lang->getMessage( $lckey );
 614                         if ( is_null( $message ) ) {
 615                                 $message = false;
 616                         }
 617                 }
 618
 619                 # Try the array of another language
 620                 if( $message === false ) {
 621                         $parts = explode( '/', $lckey );
 622                         # We may get calls for things that are http-urls from sidebar
 623                         # Let's not load nonexistent languages for those
 624                         # They usually have more than one slash.
 625                         if ( count( $parts ) == 2 && $parts[1] !== '' ) {
 626                                 $message = Language::getMessageFor( $parts[0], $parts[1] );
 627                                 if ( is_null( $message ) ) {
 628                                         $message = false;
 629                                 }
 630                         }
 631                 }
 632
 633                 # Is this a custom message? Try the default language in the db...
 634                 if( ($message === false || $message === '-' ) &&
 635                         !$this->mDisable && $useDB &&
 636                         !$isFullKey && ($langcode != $wgLanguageCode) ) {
 637                         $message = $this->getMsgFromNamespace( $uckey, $wgLanguageCode );
 638                 }
 639
 640                 # Final fallback
 641                 if( $message === false ) {
 642                         return false;
 643                 }
 644
 645                 # Fix whitespace
 646                 $message = strtr( $message,
 647                         array(
 648                                 # Fix for trailing whitespace, removed by textarea
 649                                 '&#32;' => ' ',
 650                                 # Fix for NBSP, converted to space by firefox
 651                                 '&nbsp;' => "\xc2\xa0",
 652                                 '&#160;' => "\xc2\xa0",
 653                         ) );
 654
 655                 return $message;
 656         }
 657
 658         /**
 659          * Get a message from the MediaWiki namespace, with caching. The key must
 660          * first be converted to two-part lang/msg form if necessary.
 661          *
 662          * @param $title String: Message cache key with initial uppercase letter.
 663          * @param $code String: code denoting the language to try.
 664          */
 665         function getMsgFromNamespace( $title, $code ) {
 666                 global $wgAdaptiveMessageCache;
 667
 668                 $this->load( $code );
 669                 if ( isset( $this->mCache[$code][$title] ) ) {
 670                         $entry = $this->mCache[$code][$title];
 671                         if ( substr( $entry, 0, 1 ) === ' ' ) {
 672                                 return substr( $entry, 1 );
 673                         } elseif ( $entry === '!NONEXISTENT' ) {
 674                                 return false;
 675                         } elseif( $entry === '!TOO BIG' ) {
 676                                 // Fall through and try invididual message cache below
 677                         }
 678                 } else {
 679                         // XXX: This is not cached in process cache, should it?
 680                         $message = false;
 681                         wfRunHooks('MessagesPreLoad', array( $title, &$message ) );
 682                         if ( $message !== false ) {
 683                                 return $message;
 684                         }
 685
 686                         /* If message cache is in normal mode, it is guaranteed
 687                          * (except bugs) that there is always entry (or placeholder)
 688                          * in the cache if message exists. Thus we can do minor
 689                          * performance improvement and return false early.
 690                          */
 691                         if ( !$wgAdaptiveMessageCache ) {
 692                                 return false;
 693                         }
 694                 }
 695
 696                 # Try the individual message cache
 697                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 698                 $entry = $this->mMemc->get( $titleKey );
 699                 if ( $entry ) {
 700                         if ( substr( $entry, 0, 1 ) === ' ' ) {
 701                                 $this->mCache[$code][$title] = $entry;
 702                                 return substr( $entry, 1 );
 703                         } elseif ( $entry === '!NONEXISTENT' ) {
 704                                 $this->mCache[$code][$title] = '!NONEXISTENT';
 705                                 return false;
 706                         } else {
 707                                 # Corrupt/obsolete entry, delete it
 708                                 $this->mMemc->delete( $titleKey );
 709                         }
 710                 }
 711
 712                 # Try loading it from the database
 713                 $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 714                 if ( $revision ) {
 715                         $message = $revision->getText();
 716                         $this->mCache[$code][$title] = ' ' . $message;
 717                         $this->mMemc->set( $titleKey, ' ' . $message, $this->mExpiry );
 718                 } else {
 719                         $message = false;
 720                         $this->mCache[$code][$title] = '!NONEXISTENT';
 721                         $this->mMemc->set( $titleKey, '!NONEXISTENT', $this->mExpiry );
 722                 }
 723
 724                 return $message;
 725         }
 726
 727         function transform( $message, $interface = false, $language = null ) {
 728                 // Avoid creating parser if nothing to transform
 729                 if( strpos( $message, '{{' ) === false ) {
 730                         return $message;
 731                 }
 732
 733                 global $wgParser, $wgParserConf;
 734                 if ( !$this->mParser && isset( $wgParser ) ) {
 735                         # Do some initialisation so that we don't have to do it twice
 736                         $wgParser->firstCallInit();
 737                         # Clone it and store it
 738                         $class = $wgParserConf['class'];
 739                         if ( $class == 'Parser_DiffTest' ) {
 740                                 # Uncloneable
 741                                 $this->mParser = new $class( $wgParserConf );
 742                         } else {
 743                                 $this->mParser = clone $wgParser;
 744                         }
 745                         #wfDebug( __METHOD__ . ": following contents triggered transform: $message\n" );
 746                 }
 747                 if ( $this->mParser ) {
 748                         $popts = $this->getParserOptions();
 749                         $popts->setInterfaceMessage( $interface );
 750                         $popts->setTargetLanguage( $language );
 751                         $popts->setUserLang( $language );
 752                         $message = $this->mParser->transformMsg( $message, $popts );
 753                 }
 754                 return $message;
 755         }
 756
 757         function disable() { $this->mDisable = true; }
 758         function enable() { $this->mDisable = false; }
 759
 760         /**
 761          * Clear all stored messages. Mainly used after a mass rebuild.
 762          */
 763         function clear() {
 764                 $langs = Language::getLanguageNames( false );
 765                 foreach ( array_keys($langs) as $code ) {
 766                         # Global cache
 767                         $this->mMemc->delete( wfMemcKey( 'messages', $code ) );
 768                         # Invalidate all local caches
 769                         $this->mMemc->delete( wfMemcKey( 'messages', $code, 'hash' ) );
 770                 }
 771                 $this->mLoadedLanguages = array();
 772         }
 773
 774         public function figureMessage( $key ) {
 775                 global $wgLanguageCode;
 776                 $pieces = explode( '/', $key );
 777                 if( count( $pieces ) < 2 )
 778                         return array( $key, $wgLanguageCode );
 779
 780                 $lang = array_pop( $pieces );
 781                 $validCodes = Language::getLanguageNames();
 782                 if( !array_key_exists( $lang, $validCodes ) )
 783                         return array( $key, $wgLanguageCode );
 784
 785                 $message = implode( '/', $pieces );
 786                 return array( $message, $lang );
 787         }
 788
 789         public static function logMessages() {
 790                 global $wgAdaptiveMessageCache;
 791                 if ( !$wgAdaptiveMessageCache || !self::$instance instanceof MessageCache ) {
 792                         return;
 793                 }
 794
 795                 $cachekey = wfMemckey( 'message-profiling' );
 796                 $cache = wfGetCache( CACHE_DB );
 797                 $data = $cache->get( $cachekey );
 798
 799                 if ( !$data ) $data = array();
 800
 801                 $age = self::$mAdaptiveDataAge;
 802                 $filterDate = substr( wfTimestamp( TS_MW, time()-$age ), 0, 8 );
 803                 foreach ( array_keys( $data ) as $key ) {
 804                         if ( $key < $filterDate ) unset( $data[$key] );
 805                 }
 806
 807                 $index = substr( wfTimestampNow(), 0, 8 );
 808                 if ( !isset( $data[$index] ) ) $data[$index] = array();
 809
 810                 foreach ( self::$instance->mRequestedMessages as $message => $_ ) {
 811                         if ( !isset( $data[$index][$message] ) ) $data[$index][$message] = 0;
 812                         $data[$index][$message]++;
 813                 }
 814
 815                 $cache->set( $cachekey, $data );
 816         }
 817
 818         public function getMostUsedMessages() {
 819                 $cachekey = wfMemckey( 'message-profiling' );
 820                 $cache = wfGetCache( CACHE_DB );
 821                 $data = $cache->get( $cachekey );
 822                 if ( !$data ) return array();
 823
 824                 $list = array();
 825
 826                 foreach( $data as $messages ) {
 827                         foreach( $messages as $message => $count ) {
 828                                 $key = $message;
 829                                 if ( !isset( $list[$key] ) ) $list[$key] = 0;
 830                                 $list[$key] += $count;
 831                         }
 832                 }
 833
 834                 $max = max( $list );
 835                 foreach ( $list as $message => $count ) {
 836                         if ( $count < intval( $max * self::$mAdaptiveInclusionThreshold ) ) {
 837                                 unset( $list[$message] );
 838                         }
 839                 }
 840
 841                 return array_keys( $list );
 842         }
 843
 844 }