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