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         function __construct( $memCached, $useDB, $expiry ) {
  66                 if ( !$memCached ) {
  67                         $memCached = wfGetCache( CACHE_NONE );
  68                 }
  69
  70                 $this->mMemc = $memCached;
  71                 $this->mDisable = !$useDB;
  72                 $this->mExpiry = $expiry;
  73         }
  74
  75
  76         /**
  77          * ParserOptions is lazy initialised.
  78          */
  79         function getParserOptions() {
  80                 if ( !$this->mParserOptions ) {
  81                         $this->mParserOptions = new ParserOptions;
  82                 }
  83                 return $this->mParserOptions;
  84         }
  85
  86         /**
  87          * Try to load the cache from a local file.
  88          * Actual format of the file depends on the $wgLocalMessageCacheSerialized
  89          * setting.
  90          *
  91          * @param $hash String: the hash of contents, to check validity.
  92          * @param $code Mixed: Optional language code, see documenation of load().
  93          * @return false on failure.
  94          */
  95         function loadFromLocal( $hash, $code ) {
  96                 global $wgCacheDirectory, $wgLocalMessageCacheSerialized;
  97
  98                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
  99
 100                 # Check file existence
 101                 wfSuppressWarnings();
 102                 $file = fopen( $filename, 'r' );
 103                 wfRestoreWarnings();
 104                 if ( !$file ) {
 105                         return false; // No cache file
 106                 }
 107
 108                 if ( $wgLocalMessageCacheSerialized ) {
 109                         // Check to see if the file has the hash specified
 110                         $localHash = fread( $file, 32 );
 111                         if ( $hash === $localHash ) {
 112                                 // All good, get the rest of it
 113                                 $serialized = '';
 114                                 while ( !feof( $file ) ) {
 115                                         $serialized .= fread( $file, 100000 );
 116                                 }
 117                                 fclose( $file );
 118                                 return $this->setCache( unserialize( $serialized ), $code );
 119                         } else {
 120                                 fclose( $file );
 121                                 return false; // Wrong hash
 122                         }
 123                 } else {
 124                         $localHash=substr(fread($file,40),8);
 125                         fclose($file);
 126                         if ($hash!=$localHash) {
 127                                 return false; // Wrong hash
 128                         }
 129
 130                         # Require overwrites the member variable or just shadows it?
 131                         require( $filename );
 132                         return $this->setCache( $this->mCache, $code );
 133                 }
 134         }
 135
 136         /**
 137          * Save the cache to a local file.
 138          */
 139         function saveToLocal( $serialized, $hash, $code ) {
 140                 global $wgCacheDirectory;
 141
 142                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 143                 wfMkdirParents( $wgCacheDirectory ); // might fail
 144
 145                 wfSuppressWarnings();
 146                 $file = fopen( $filename, 'w' );
 147                 wfRestoreWarnings();
 148
 149                 if ( !$file ) {
 150                         wfDebug( "Unable to open local cache file for writing\n" );
 151                         return;
 152                 }
 153
 154                 fwrite( $file, $hash . $serialized );
 155                 fclose( $file );
 156                 @chmod( $filename, 0666 );
 157         }
 158
 159         function saveToScript( $array, $hash, $code ) {
 160                 global $wgCacheDirectory;
 161
 162                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 163                 $tempFilename = $filename . '.tmp';
 164                 wfMkdirParents( $wgCacheDirectory ); // might fail
 165
 166                 wfSuppressWarnings();
 167                 $file = fopen( $tempFilename, 'w');
 168                 wfRestoreWarnings();
 169
 170                 if ( !$file ) {
 171                         wfDebug( "Unable to open local cache file for writing\n" );
 172                         return;
 173                 }
 174
 175                 fwrite($file,"<?php\n//$hash\n\n \$this->mCache = array(");
 176
 177                 foreach ( $array as $key => $message ) {
 178                         $key = $this->escapeForScript($key);
 179                         $message = $this->escapeForScript($message);
 180                         fwrite($file, "'$key' => '$message',\n");
 181                 }
 182
 183                 fwrite($file,");\n?>");
 184                 fclose($file);
 185                 rename($tempFilename, $filename);
 186         }
 187
 188         function escapeForScript($string) {
 189                 $string = str_replace( '\\', '\\\\', $string );
 190                 $string = str_replace( '\'', '\\\'', $string );
 191                 return $string;
 192         }
 193
 194         /**
 195          * Set the cache to $cache, if it is valid. Otherwise set the cache to false.
 196          */
 197         function setCache( $cache, $code ) {
 198                 if ( isset( $cache['VERSION'] ) && $cache['VERSION'] == MSG_CACHE_VERSION ) {
 199                         $this->mCache[$code] = $cache;
 200                         return true;
 201                 } else {
 202                         return false;
 203                 }
 204         }
 205
 206         /**
 207          * Loads messages from caches or from database in this order:
 208          * (1) local message cache (if $wgUseLocalMessageCache is enabled)
 209          * (2) memcached
 210          * (3) from the database.
 211          *
 212          * When succesfully loading from (2) or (3), all higher level caches are
 213          * updated for the newest version.
 214          *
 215          * Nothing is loaded if member variable mDisable is true, either manually
 216          * set by calling code or if message loading fails (is this possible?).
 217          *
 218          * Returns true if cache is already populated or it was succesfully populated,
 219          * or false if populating empty cache fails. Also returns true if MessageCache
 220          * is disabled.
 221          *
 222          * @param $code String: language to which load messages
 223          */
 224         function load( $code = false ) {
 225                 global $wgUseLocalMessageCache;
 226
 227                 if( !is_string( $code ) ) {
 228                         # This isn't really nice, so at least make a note about it and try to
 229                         # fall back
 230                         wfDebug( __METHOD__ . " called without providing a language code\n" );
 231                         $code = 'en';
 232                 }
 233
 234                 # Don't do double loading...
 235                 if ( isset($this->mLoadedLanguages[$code]) ) return true;
 236
 237                 # 8 lines of code just to say (once) that message cache is disabled
 238                 if ( $this->mDisable ) {
 239                         static $shownDisabled = false;
 240                         if ( !$shownDisabled ) {
 241                                 wfDebug( __METHOD__ . ": disabled\n" );
 242                                 $shownDisabled = true;
 243                         }
 244                         return true;
 245                 }
 246
 247                 # Loading code starts
 248                 wfProfileIn( __METHOD__ );
 249                 $success = false; # Keep track of success
 250                 $where = array(); # Debug info, delayed to avoid spamming debug log too much
 251                 $cacheKey = wfMemcKey( 'messages', $code ); # Key in memc for messages
 252
 253
 254                 # (1) local cache
 255                 # Hash of the contents is stored in memcache, to detect if local cache goes
 256                 # out of date (due to update in other thread?)
 257                 if ( $wgUseLocalMessageCache ) {
 258                         wfProfileIn( __METHOD__ . '-fromlocal' );
 259
 260                         $hash = $this->mMemc->get( wfMemcKey( 'messages', $code, 'hash' ) );
 261                         if ( $hash ) {
 262                                 $success = $this->loadFromLocal( $hash, $code );
 263                                 if ( $success ) $where[] = 'got from local cache';
 264                         }
 265                         wfProfileOut( __METHOD__ . '-fromlocal' );
 266                 }
 267
 268                 # (2) memcache
 269                 # Fails if nothing in cache, or in the wrong version.
 270                 if ( !$success ) {
 271                         wfProfileIn( __METHOD__ . '-fromcache' );
 272                         $cache = $this->mMemc->get( $cacheKey );
 273                         $success = $this->setCache( $cache, $code );
 274                         if ( $success ) {
 275                                 $where[] = 'got from global cache';
 276                                 $this->saveToCaches( $cache, false, $code );
 277                         }
 278                         wfProfileOut( __METHOD__ . '-fromcache' );
 279                 }
 280
 281
 282                 # (3)
 283                 # Nothing in caches... so we need create one and store it in caches
 284                 if ( !$success ) {
 285                         $where[] = 'cache is empty';
 286                         $where[] = 'loading from database';
 287
 288                         $this->lock($cacheKey);
 289
 290                         # Limit the concurrency of loadFromDB to a single process
 291                         # This prevents the site from going down when the cache expires
 292                         $statusKey = wfMemcKey( 'messages', $code, 'status' );
 293                         $success = $this->mMemc->add( $statusKey, 'loading', MSG_LOAD_TIMEOUT );
 294                         if ( $success ) {
 295                                 $cache = $this->loadFromDB( $code );
 296                                 $success = $this->setCache( $cache, $code );
 297                         }
 298                         if ( $success ) {
 299                                 $success = $this->saveToCaches( $cache, true, $code );
 300                                 if ( $success ) {
 301                                         $this->mMemc->delete( $statusKey );
 302                                 } else {
 303                                         $this->mMemc->set( $statusKey, 'error', 60*5 );
 304                                         wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 305                                 }
 306                         }
 307                         $this->unlock($cacheKey);
 308                 }
 309
 310                 if ( !$success ) {
 311                         # Bad luck... this should not happen
 312                         $where[] = 'loading FAILED - cache is disabled';
 313                         $info = implode( ', ', $where );
 314                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 315                         $this->mDisable = true;
 316                         $this->mCache = false;
 317                 } else {
 318                         # All good, just record the success
 319                         $info = implode( ', ', $where );
 320                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 321                         $this->mLoadedLanguages[$code] = true;
 322                 }
 323                 wfProfileOut( __METHOD__ );
 324                 return $success;
 325         }
 326
 327         /**
 328          * Loads cacheable messages from the database. Messages bigger than
 329          * $wgMaxMsgCacheEntrySize are assigned a special value, and are loaded
 330          * on-demand from the database later.
 331          *
 332          * @param $code \string Language code.
 333          * @return \array Loaded messages for storing in caches.
 334          */
 335         function loadFromDB( $code ) {
 336                 wfProfileIn( __METHOD__ );
 337                 global $wgMaxMsgCacheEntrySize, $wgLanguageCode, $wgAdaptiveMessageCache;
 338                 $dbr = wfGetDB( DB_SLAVE );
 339                 $cache = array();
 340
 341                 # Common conditions
 342                 $conds = array(
 343                         'page_is_redirect' => 0,
 344                         'page_namespace' => NS_MEDIAWIKI,
 345                 );
 346
 347                 $mostused = array();
 348                 if ( $wgAdaptiveMessageCache ) {
 349                         $mostused = $this->getMostUsedMessages();
 350                         if ( $code !== $wgLanguageCode ) {
 351                                 foreach ( $mostused as $key => $value ) $mostused[$key] = "$value/$code";
 352                         }
 353                 }
 354
 355                 if ( count( $mostused ) ) {
 356                         $conds['page_title'] = $mostused;
 357                 } elseif ( $code !== $wgLanguageCode ) {
 358                         $conds[] = 'page_title' . $dbr->buildLike( $dbr->anyString(), "/$code" );
 359                 } else {
 360                         # Effectively disallows use of '/' character in NS_MEDIAWIKI for uses
 361                         # other than language code.
 362                         $conds[] = 'page_title NOT' . $dbr->buildLike( $dbr->anyString(), '/', $dbr->anyString() );
 363                 }
 364
 365                 # Conditions to fetch oversized pages to ignore them
 366                 $bigConds = $conds;
 367                 $bigConds[] = 'page_len > ' . intval( $wgMaxMsgCacheEntrySize );
 368
 369                 # Load titles for all oversized pages in the MediaWiki namespace
 370                 $res = $dbr->select( 'page', 'page_title', $bigConds, __METHOD__ . "($code)-big" );
 371                 foreach ( $res as $row ) {
 372                         $cache[$row->page_title] = '!TOO BIG';
 373                 }
 374
 375                 # Conditions to load the remaining pages with their contents
 376                 $smallConds = $conds;
 377                 $smallConds[] = 'page_latest=rev_id';
 378                 $smallConds[] = 'rev_text_id=old_id';
 379                 $smallConds[] = 'page_len <= ' . intval( $wgMaxMsgCacheEntrySize );
 380
 381                 $res = $dbr->select( array( 'page', 'revision', 'text' ),
 382                         array( 'page_title', 'old_text', 'old_flags' ),
 383                         $smallConds, __METHOD__ . "($code)-small" );
 384
 385                 foreach ( $res as $row ) {
 386                         $cache[$row->page_title] = ' ' . Revision::getRevisionText( $row );
 387                 }
 388
 389                 foreach ( $mostused as $key ) {
 390                         if ( !isset( $cache[$key] ) ) {
 391                                 $cache[$key] = '!NONEXISTENT';
 392                         }
 393                 }
 394
 395                 $cache['VERSION'] = MSG_CACHE_VERSION;
 396                 wfProfileOut( __METHOD__ );
 397                 return $cache;
 398         }
 399
 400         /**
 401          * Updates cache as necessary when message page is changed
 402          *
 403          * @param $title String: name of the page changed.
 404          * @param $text Mixed: new contents of the page.
 405          */
 406         public function replace( $title, $text ) {
 407                 global $wgMaxMsgCacheEntrySize;
 408                 wfProfileIn( __METHOD__ );
 409
 410                 if ( $this->mDisable ) {
 411                         return;
 412                 }
 413
 414                 list( $msg, $code ) = $this->figureMessage( $title );
 415
 416                 $cacheKey = wfMemcKey( 'messages', $code );
 417                 $this->load( $code );
 418                 $this->lock( $cacheKey );
 419
 420                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 421
 422                 if ( $text === false ) {
 423                         # Article was deleted
 424                         $this->mCache[$code][$title] = '!NONEXISTENT';
 425                         $this->mMemc->delete( $titleKey );
 426
 427                 } elseif ( strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
 428                         # Check for size
 429                         $this->mCache[$code][$title] = '!TOO BIG';
 430                         $this->mMemc->set( $titleKey, ' ' . $text, $this->mExpiry );
 431
 432                 } else {
 433                         $this->mCache[$code][$title] = ' ' . $text;
 434                         $this->mMemc->delete( $titleKey );
 435                 }
 436
 437                 # Update caches
 438                 $this->saveToCaches( $this->mCache[$code], true, $code );
 439                 $this->unlock( $cacheKey );
 440
 441                 // Also delete cached sidebar... just in case it is affected
 442                 $codes = array( $code );
 443                 if ( $code === 'en'  ) {
 444                         // Delete all sidebars, like for example on action=purge on the
 445                         // sidebar messages
 446                         $codes = array_keys( Language::getLanguageNames() );
 447                 }
 448
 449                 global $parserMemc;
 450                 foreach ( $codes as $code ) {
 451                         $sidebarKey = wfMemcKey( 'sidebar', $code );
 452                         $parserMemc->delete( $sidebarKey );
 453                 }
 454
 455                 // Update the message in the message blob store
 456                 global $wgContLang;
 457                 MessageBlobStore::updateMessage( $wgContLang->lcfirst( $msg ) );
 458
 459                 wfRunHooks( "MessageCacheReplace", array( $title, $text ) );
 460
 461                 wfProfileOut( __METHOD__ );
 462         }
 463
 464         /**
 465          * Shortcut to update caches.
 466          *
 467          * @param $cache Array: cached messages with a version.
 468          * @param $memc Bool: Wether to update or not memcache.
 469          * @param $code String: Language code.
 470          * @return False on somekind of error.
 471          */
 472         protected function saveToCaches( $cache, $memc = true, $code = false ) {
 473                 wfProfileIn( __METHOD__ );
 474                 global $wgUseLocalMessageCache, $wgLocalMessageCacheSerialized;
 475
 476                 $cacheKey = wfMemcKey( 'messages', $code );
 477
 478                 if ( $memc ) {
 479                         $success = $this->mMemc->set( $cacheKey, $cache, $this->mExpiry );
 480                 } else {
 481                         $success = true;
 482                 }
 483
 484                 # Save to local cache
 485                 if ( $wgUseLocalMessageCache ) {
 486                         $serialized = serialize( $cache );
 487                         $hash = md5( $serialized );
 488                         $this->mMemc->set( wfMemcKey( 'messages', $code, 'hash' ), $hash, $this->mExpiry );
 489                         if ($wgLocalMessageCacheSerialized) {
 490                                 $this->saveToLocal( $serialized, $hash, $code );
 491                         } else {
 492                                 $this->saveToScript( $cache, $hash, $code );
 493                         }
 494                 }
 495
 496                 wfProfileOut( __METHOD__ );
 497                 return $success;
 498         }
 499
 500         /**
 501          * Represents a write lock on the messages key
 502          *
 503          * @return Boolean: success
 504          */
 505         function lock($key) {
 506                 $lockKey = $key . ':lock';
 507                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 508                         sleep(1);
 509                 }
 510
 511                 return $i >= MSG_WAIT_TIMEOUT;
 512         }
 513
 514         function unlock($key) {
 515                 $lockKey = $key . ':lock';
 516                 $this->mMemc->delete( $lockKey );
 517         }
 518
 519         /**
 520          * Get a message from either the content language or the user language.
 521          *
 522          * @param $key String: the message cache key
 523          * @param $useDB Boolean: get the message from the DB, false to use only
 524          *               the localisation
 525          * @param $langcode String: code of the language to get the message for, if
 526          *                  it is a valid code create a language for that language,
 527          *                  if it is a string but not a valid code then make a basic
 528          *                  language object, if it is a false boolean then use the
 529          *                  current users language (as a fallback for the old
 530          *                  parameter functionality), or if it is a true boolean
 531          *                  then use the wikis content language (also as a
 532          *                  fallback).
 533          * @param $isFullKey Boolean: specifies whether $key is a two part key
 534          *                   "msg/lang".
 535          */
 536         function get( $key, $useDB = true, $langcode = true, $isFullKey = false ) {
 537                 global $wgLanguageCode, $wgContLang;
 538
 539                 if ( !is_string( $key ) ) {
 540                         throw new MWException( "Non-string key given" );
 541                 }
 542
 543                 if ( strval( $key ) === '' ) {
 544                         # Shortcut: the empty key is always missing
 545                         return false;
 546                 }
 547
 548                 $lang = wfGetLangObj( $langcode );
 549                 if ( !$lang ) {
 550                         throw new MWException( "Bad lang code $langcode given" );
 551                 }
 552
 553                 // Don't change getPreferredVariant() to getCode() / mCode, for
 554                 // more details, see the comment in Language::getMessage().
 555                 $langcode = $lang->getPreferredVariant();
 556
 557                 $message = false;
 558
 559                 # Normalise title-case input (with some inlining)
 560                 $lckey = str_replace( ' ', '_', $key );
 561                 if ( ord( $key ) < 128 ) {
 562                         $lckey[0] = strtolower( $lckey[0] );
 563                         $uckey = ucfirst( $lckey );
 564                 } else {
 565                         $lckey = $wgContLang->lcfirst( $lckey );
 566                         $uckey = $wgContLang->ucfirst( $lckey );
 567                 }
 568
 569                 /* Record each message request, but only once per request.
 570                  * This information is not used unless $wgAdaptiveMessageCache
 571                  * is enabled. */
 572                 $this->mRequestedMessages[$uckey] = true;
 573
 574                 # Try the MediaWiki namespace
 575                 if( !$this->mDisable && $useDB ) {
 576                         $title = $uckey;
 577                         if(!$isFullKey && ( $langcode != $wgLanguageCode ) ) {
 578                                 $title .= '/' . $langcode;
 579                         }
 580                         $message = $this->getMsgFromNamespace( $title, $langcode );
 581                 }
 582
 583                 # Try the array in the language object
 584                 if ( $message === false ) {
 585                         $message = $lang->getMessage( $lckey );
 586                         if ( is_null( $message ) ) {
 587                                 $message = false;
 588                         }
 589                 }
 590
 591                 # Try the array of another language
 592                 if( $message === false ) {
 593                         $parts = explode( '/', $lckey );
 594                         # We may get calls for things that are http-urls from sidebar
 595                         # Let's not load nonexistent languages for those
 596                         # They usually have more than one slash.
 597                         if ( count( $parts ) == 2 && $parts[1] !== '' ) {
 598                                 $message = Language::getMessageFor( $parts[0], $parts[1] );
 599                                 if ( is_null( $message ) ) {
 600                                         $message = false;
 601                                 }
 602                         }
 603                 }
 604
 605                 # Is this a custom message? Try the default language in the db...
 606                 if( ($message === false || $message === '-' ) &&
 607                         !$this->mDisable && $useDB &&
 608                         !$isFullKey && ($langcode != $wgLanguageCode) ) {
 609                         $message = $this->getMsgFromNamespace( $uckey, $wgLanguageCode );
 610                 }
 611
 612                 # Final fallback
 613                 if( $message === false ) {
 614                         return false;
 615                 }
 616
 617                 # Fix whitespace
 618                 $message = strtr( $message,
 619                         array(
 620                                 # Fix for trailing whitespace, removed by textarea
 621                                 '&#32;' => ' ',
 622                                 # Fix for NBSP, converted to space by firefox
 623                                 '&nbsp;' => "\xc2\xa0",
 624                                 '&#160;' => "\xc2\xa0",
 625                         ) );
 626
 627                 return $message;
 628         }
 629
 630         /**
 631          * Get a message from the MediaWiki namespace, with caching. The key must
 632          * first be converted to two-part lang/msg form if necessary.
 633          *
 634          * @param $title String: Message cache key with initial uppercase letter.
 635          * @param $code String: code denoting the language to try.
 636          */
 637         function getMsgFromNamespace( $title, $code ) {
 638                 global $wgAdaptiveMessageCache;
 639
 640                 $this->load( $code );
 641                 if ( isset( $this->mCache[$code][$title] ) ) {
 642                         $entry = $this->mCache[$code][$title];
 643                         if ( substr( $entry, 0, 1 ) === ' ' ) {
 644                                 return substr( $entry, 1 );
 645                         } elseif ( $entry === '!NONEXISTENT' ) {
 646                                 return false;
 647                         } elseif( $entry === '!TOO BIG' ) {
 648                                 // Fall through and try invididual message cache below
 649                         }
 650                 } else {
 651                         // XXX: This is not cached in process cache, should it?
 652                         $message = false;
 653                         wfRunHooks('MessagesPreLoad', array( $title, &$message ) );
 654                         if ( $message !== false ) {
 655                                 return $message;
 656                         }
 657
 658                         /* If message cache is in normal mode, it is guaranteed
 659                          * (except bugs) that there is always entry (or placeholder)
 660                          * in the cache if message exists. Thus we can do minor
 661                          * performance improvement and return false early.
 662                          */
 663                         if ( !$wgAdaptiveMessageCache ) {
 664                                 return false;
 665                         }
 666                 }
 667
 668                 # Try the individual message cache
 669                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 670                 $entry = $this->mMemc->get( $titleKey );
 671                 if ( $entry ) {
 672                         if ( substr( $entry, 0, 1 ) === ' ' ) {
 673                                 $this->mCache[$code][$title] = $entry;
 674                                 return substr( $entry, 1 );
 675                         } elseif ( $entry === '!NONEXISTENT' ) {
 676                                 $this->mCache[$code][$title] = '!NONEXISTENT';
 677                                 return false;
 678                         } else {
 679                                 # Corrupt/obsolete entry, delete it
 680                                 $this->mMemc->delete( $titleKey );
 681                         }
 682                 }
 683
 684                 # Try loading it from the database
 685                 $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 686                 if ( $revision ) {
 687                         $message = $revision->getText();
 688                         $this->mCache[$code][$title] = ' ' . $message;
 689                         $this->mMemc->set( $titleKey, ' ' . $message, $this->mExpiry );
 690                 } else {
 691                         $message = false;
 692                         $this->mCache[$code][$title] = '!NONEXISTENT';
 693                         $this->mMemc->set( $titleKey, '!NONEXISTENT', $this->mExpiry );
 694                 }
 695
 696                 return $message;
 697         }
 698
 699         function transform( $message, $interface = false, $language = null ) {
 700                 // Avoid creating parser if nothing to transform
 701                 if( strpos( $message, '{{' ) === false ) {
 702                         return $message;
 703                 }
 704
 705                 global $wgParser, $wgParserConf;
 706                 if ( !$this->mParser && isset( $wgParser ) ) {
 707                         # Do some initialisation so that we don't have to do it twice
 708                         $wgParser->firstCallInit();
 709                         # Clone it and store it
 710                         $class = $wgParserConf['class'];
 711                         if ( $class == 'Parser_DiffTest' ) {
 712                                 # Uncloneable
 713                                 $this->mParser = new $class( $wgParserConf );
 714                         } else {
 715                                 $this->mParser = clone $wgParser;
 716                         }
 717                         #wfDebug( __METHOD__ . ": following contents triggered transform: $message\n" );
 718                 }
 719                 if ( $this->mParser ) {
 720                         $popts = $this->getParserOptions();
 721                         $popts->setInterfaceMessage( $interface );
 722                         $popts->setTargetLanguage( $language );
 723                         $popts->setUserLang( $language );
 724                         $message = $this->mParser->transformMsg( $message, $popts );
 725                 }
 726                 return $message;
 727         }
 728
 729         function disable() { $this->mDisable = true; }
 730         function enable() { $this->mDisable = false; }
 731
 732         /** @deprecated */
 733         function disableTransform(){
 734                 wfDeprecated( __METHOD__ );
 735         }
 736         function enableTransform() {
 737                 wfDeprecated( __METHOD__ );
 738         }
 739         function setTransform( $x ) {
 740                 wfDeprecated( __METHOD__ );
 741         }
 742         function getTransform() {
 743                 wfDeprecated( __METHOD__ );
 744                 return false;
 745         }
 746
 747         /**
 748          * Clear all stored messages. Mainly used after a mass rebuild.
 749          */
 750         function clear() {
 751                 $langs = Language::getLanguageNames( false );
 752                 foreach ( array_keys($langs) as $code ) {
 753                         # Global cache
 754                         $this->mMemc->delete( wfMemcKey( 'messages', $code ) );
 755                         # Invalidate all local caches
 756                         $this->mMemc->delete( wfMemcKey( 'messages', $code, 'hash' ) );
 757                 }
 758                 $this->mLoadedLanguages = array();
 759         }
 760
 761         /**
 762          * Add a message to the cache
 763          * @deprecated Use $wgExtensionMessagesFiles
 764          *
 765          * @param $key Mixed
 766          * @param $value Mixed
 767          * @param $lang String: the messages language, English by default
 768          */
 769         function addMessage( $key, $value, $lang = 'en' ) {
 770                 wfDeprecated( __METHOD__ );
 771                 $lc = Language::getLocalisationCache();
 772                 $lc->addLegacyMessages( array( $lang => array( $key => $value ) ) );
 773         }
 774
 775         /**
 776          * Add an associative array of message to the cache
 777          * @deprecated Use $wgExtensionMessagesFiles
 778          *
 779          * @param $messages Array: an associative array of key => values to be added
 780          * @param $lang String: the messages language, English by default
 781          */
 782         function addMessages( $messages, $lang = 'en' ) {
 783                 wfDeprecated( __METHOD__ );
 784                 $lc = Language::getLocalisationCache();
 785                 $lc->addLegacyMessages( array( $lang => $messages ) );
 786         }
 787
 788         /**
 789          * Add a 2-D array of messages by lang. Useful for extensions.
 790          * @deprecated Use $wgExtensionMessagesFiles
 791          *
 792          * @param $messages Array: the array to be added
 793          */
 794         function addMessagesByLang( $messages ) {
 795                 wfDeprecated( __METHOD__ );
 796                 $lc = Language::getLocalisationCache();
 797                 $lc->addLegacyMessages( $messages );
 798         }
 799
 800         /**
 801          * Set a hook for addMessagesByLang()
 802          */
 803         function setExtensionMessagesHook( $callback ) {
 804                 $this->mAddMessagesHook = $callback;
 805         }
 806
 807         /**
 808          * @deprecated
 809          */
 810         function loadAllMessages( $lang = false ) {
 811         }
 812
 813         /**
 814          * @deprecated
 815          */
 816         function loadMessagesFile( $filename, $langcode = false ) {
 817         }
 818
 819         public function figureMessage( $key ) {
 820                 global $wgLanguageCode;
 821                 $pieces = explode( '/', $key );
 822                 if( count( $pieces ) < 2 )
 823                         return array( $key, $wgLanguageCode );
 824
 825                 $lang = array_pop( $pieces );
 826                 $validCodes = Language::getLanguageNames();
 827                 if( !array_key_exists( $lang, $validCodes ) )
 828                         return array( $key, $wgLanguageCode );
 829
 830                 $message = implode( '/', $pieces );
 831                 return array( $message, $lang );
 832         }
 833
 834         public static function logMessages() {
 835                 global $wgMessageCache, $wgAdaptiveMessageCache;
 836                 if ( !$wgAdaptiveMessageCache || !$wgMessageCache instanceof MessageCache ) {
 837                         return;
 838                 }
 839
 840                 $cachekey = wfMemckey( 'message-profiling' );
 841                 $cache = wfGetCache( CACHE_DB );
 842                 $data = $cache->get( $cachekey );
 843
 844                 if ( !$data ) $data = array();
 845
 846                 $age = self::$mAdaptiveDataAge;
 847                 $filterDate = substr( wfTimestamp( TS_MW, time()-$age ), 0, 8 );
 848                 foreach ( array_keys( $data ) as $key ) {
 849                         if ( $key < $filterDate ) unset( $data[$key] );
 850                 }
 851
 852                 $index = substr( wfTimestampNow(), 0, 8 );
 853                 if ( !isset( $data[$index] ) ) $data[$index] = array();
 854
 855                 foreach ( $wgMessageCache->mRequestedMessages as $message => $_ ) {
 856                         if ( !isset( $data[$index][$message] ) ) $data[$index][$message] = 0;
 857                         $data[$index][$message]++;
 858                 }
 859
 860                 $cache->set( $cachekey, $data );
 861         }
 862
 863         public function getMostUsedMessages() {
 864                 $cachekey = wfMemckey( 'message-profiling' );
 865                 $cache = wfGetCache( CACHE_DB );
 866                 $data = $cache->get( $cachekey );
 867                 if ( !$data ) return array();
 868
 869                 $list = array();
 870
 871                 foreach( $data as $messages ) {
 872                         foreach( $messages as $message => $count ) {
 873                                 $key = $message;
 874                                 if ( !isset( $list[$key] ) ) $list[$key] = 0;
 875                                 $list[$key] += $count;
 876                         }
 877                 }
 878
 879                 $max = max( $list );
 880                 foreach ( $list as $message => $count ) {
 881                         if ( $count < intval( $max * self::$mAdaptiveInclusionThreshold ) ) {
 882                                 unset( $list[$message] );
 883                         }
 884                 }
 885
 886                 return array_keys( $list );
 887         }
 888
 889 }