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 = $expiry;
 101         }
 102
 103         /**
 104          * ParserOptions is lazy initialised.
 105          *
 106          * @return ParserOptions
 107          */
 108         function getParserOptions() {
 109                 if ( !$this->mParserOptions ) {
 110                         $this->mParserOptions = new ParserOptions;
 111                 }
 112                 return $this->mParserOptions;
 113         }
 114
 115         /**
 116          * Try to load the cache from a local file.
 117          * Actual format of the file depends on the $wgLocalMessageCacheSerialized
 118          * setting.
 119          *
 120          * @param $hash String: the hash of contents, to check validity.
 121          * @param $code Mixed: Optional language code, see documenation of load().
 122          * @return false on failure.
 123          */
 124         function loadFromLocal( $hash, $code ) {
 125                 global $wgCacheDirectory, $wgLocalMessageCacheSerialized;
 126
 127                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 128
 129                 # Check file existence
 130                 wfSuppressWarnings();
 131                 $file = fopen( $filename, 'r' );
 132                 wfRestoreWarnings();
 133                 if ( !$file ) {
 134                         return false; // No cache file
 135                 }
 136
 137                 if ( $wgLocalMessageCacheSerialized ) {
 138                         // Check to see if the file has the hash specified
 139                         $localHash = fread( $file, 32 );
 140                         if ( $hash === $localHash ) {
 141                                 // All good, get the rest of it
 142                                 $serialized = '';
 143                                 while ( !feof( $file ) ) {
 144                                         $serialized .= fread( $file, 100000 );
 145                                 }
 146                                 fclose( $file );
 147                                 return $this->setCache( unserialize( $serialized ), $code );
 148                         } else {
 149                                 fclose( $file );
 150                                 return false; // Wrong hash
 151                         }
 152                 } else {
 153                         $localHash = substr( fread( $file, 40 ), 8 );
 154                         fclose( $file );
 155                         if ( $hash != $localHash ) {
 156                                 return false; // Wrong hash
 157                         }
 158
 159                         # Require overwrites the member variable or just shadows it?
 160                         require( $filename );
 161                         return $this->setCache( $this->mCache, $code );
 162                 }
 163         }
 164
 165         /**
 166          * Save the cache to a local file.
 167          */
 168         function saveToLocal( $serialized, $hash, $code ) {
 169                 global $wgCacheDirectory;
 170
 171                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 172                 wfMkdirParents( $wgCacheDirectory ); // might fail
 173
 174                 wfSuppressWarnings();
 175                 $file = fopen( $filename, 'w' );
 176                 wfRestoreWarnings();
 177
 178                 if ( !$file ) {
 179                         wfDebug( "Unable to open local cache file for writing\n" );
 180                         return;
 181                 }
 182
 183                 fwrite( $file, $hash . $serialized );
 184                 fclose( $file );
 185                 @chmod( $filename, 0666 );
 186         }
 187
 188         function saveToScript( $array, $hash, $code ) {
 189                 global $wgCacheDirectory;
 190
 191                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 192                 $tempFilename = $filename . '.tmp';
 193                 wfMkdirParents( $wgCacheDirectory ); // might fail
 194
 195                 wfSuppressWarnings();
 196                 $file = fopen( $tempFilename, 'w' );
 197                 wfRestoreWarnings();
 198
 199                 if ( !$file ) {
 200                         wfDebug( "Unable to open local cache file for writing\n" );
 201                         return;
 202                 }
 203
 204                 fwrite( $file, "<?php\n//$hash\n\n \$this->mCache = array(" );
 205
 206                 foreach ( $array as $key => $message ) {
 207                         $key = $this->escapeForScript( $key );
 208                         $message = $this->escapeForScript( $message );
 209                         fwrite( $file, "'$key' => '$message',\n" );
 210                 }
 211
 212                 fwrite( $file, ");\n?>" );
 213                 fclose( $file);
 214                 rename( $tempFilename, $filename );
 215         }
 216
 217         function escapeForScript( $string ) {
 218                 $string = str_replace( '\\', '\\\\', $string );
 219                 $string = str_replace( '\'', '\\\'', $string );
 220                 return $string;
 221         }
 222
 223         /**
 224          * Set the cache to $cache, if it is valid. Otherwise set the cache to false.
 225          *
 226          * @return bool
 227          */
 228         function setCache( $cache, $code ) {
 229                 if ( isset( $cache['VERSION'] ) && $cache['VERSION'] == MSG_CACHE_VERSION ) {
 230                         $this->mCache[$code] = $cache;
 231                         return true;
 232                 } else {
 233                         return false;
 234                 }
 235         }
 236
 237         /**
 238          * Loads messages from caches or from database in this order:
 239          * (1) local message cache (if $wgUseLocalMessageCache is enabled)
 240          * (2) memcached
 241          * (3) from the database.
 242          *
 243          * When succesfully loading from (2) or (3), all higher level caches are
 244          * updated for the newest version.
 245          *
 246          * Nothing is loaded if member variable mDisable is true, either manually
 247          * set by calling code or if message loading fails (is this possible?).
 248          *
 249          * Returns true if cache is already populated or it was succesfully populated,
 250          * or false if populating empty cache fails. Also returns true if MessageCache
 251          * is disabled.
 252          *
 253          * @param $code String: language to which load messages
 254          */
 255         function load( $code = false ) {
 256                 global $wgUseLocalMessageCache;
 257
 258                 if( !is_string( $code ) ) {
 259                         # This isn't really nice, so at least make a note about it and try to
 260                         # fall back
 261                         wfDebug( __METHOD__ . " called without providing a language code\n" );
 262                         $code = 'en';
 263                 }
 264
 265                 # Don't do double loading...
 266                 if ( isset( $this->mLoadedLanguages[$code] ) ) {
 267                         return true;
 268                 }
 269
 270                 # 8 lines of code just to say (once) that message cache is disabled
 271                 if ( $this->mDisable ) {
 272                         static $shownDisabled = false;
 273                         if ( !$shownDisabled ) {
 274                                 wfDebug( __METHOD__ . ": disabled\n" );
 275                                 $shownDisabled = true;
 276                         }
 277                         return true;
 278                 }
 279
 280                 # Loading code starts
 281                 wfProfileIn( __METHOD__ );
 282                 $success = false; # Keep track of success
 283                 $where = array(); # Debug info, delayed to avoid spamming debug log too much
 284                 $cacheKey = wfMemcKey( 'messages', $code ); # Key in memc for messages
 285
 286                 # (1) local cache
 287                 # Hash of the contents is stored in memcache, to detect if local cache goes
 288                 # out of date (due to update in other thread?)
 289                 if ( $wgUseLocalMessageCache ) {
 290                         wfProfileIn( __METHOD__ . '-fromlocal' );
 291
 292                         $hash = $this->mMemc->get( wfMemcKey( 'messages', $code, 'hash' ) );
 293                         if ( $hash ) {
 294                                 $success = $this->loadFromLocal( $hash, $code );
 295                                 if ( $success ) $where[] = 'got from local cache';
 296                         }
 297                         wfProfileOut( __METHOD__ . '-fromlocal' );
 298                 }
 299
 300                 # (2) memcache
 301                 # Fails if nothing in cache, or in the wrong version.
 302                 if ( !$success ) {
 303                         wfProfileIn( __METHOD__ . '-fromcache' );
 304                         $cache = $this->mMemc->get( $cacheKey );
 305                         $success = $this->setCache( $cache, $code );
 306                         if ( $success ) {
 307                                 $where[] = 'got from global cache';
 308                                 $this->saveToCaches( $cache, false, $code );
 309                         }
 310                         wfProfileOut( __METHOD__ . '-fromcache' );
 311                 }
 312
 313                 # (3)
 314                 # Nothing in caches... so we need create one and store it in caches
 315                 if ( !$success ) {
 316                         $where[] = 'cache is empty';
 317                         $where[] = 'loading from database';
 318
 319                         $this->lock( $cacheKey );
 320
 321                         # Limit the concurrency of loadFromDB to a single process
 322                         # This prevents the site from going down when the cache expires
 323                         $statusKey = wfMemcKey( 'messages', $code, 'status' );
 324                         $success = $this->mMemc->add( $statusKey, 'loading', MSG_LOAD_TIMEOUT );
 325                         if ( $success ) {
 326                                 $cache = $this->loadFromDB( $code );
 327                                 $success = $this->setCache( $cache, $code );
 328                         }
 329                         if ( $success ) {
 330                                 $success = $this->saveToCaches( $cache, true, $code );
 331                                 if ( $success ) {
 332                                         $this->mMemc->delete( $statusKey );
 333                                 } else {
 334                                         $this->mMemc->set( $statusKey, 'error', 60 * 5 );
 335                                         wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 336                                 }
 337                         }
 338                         $this->unlock($cacheKey);
 339                 }
 340
 341                 if ( !$success ) {
 342                         # Bad luck... this should not happen
 343                         $where[] = 'loading FAILED - cache is disabled';
 344                         $info = implode( ', ', $where );
 345                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 346                         $this->mDisable = true;
 347                         $this->mCache = false;
 348                 } else {
 349                         # All good, just record the success
 350                         $info = implode( ', ', $where );
 351                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 352                         $this->mLoadedLanguages[$code] = true;
 353                 }
 354                 wfProfileOut( __METHOD__ );
 355                 return $success;
 356         }
 357
 358         /**
 359          * Loads cacheable messages from the database. Messages bigger than
 360          * $wgMaxMsgCacheEntrySize are assigned a special value, and are loaded
 361          * on-demand from the database later.
 362          *
 363          * @param $code String: language code.
 364          * @return Array: loaded messages for storing in caches.
 365          */
 366         function loadFromDB( $code ) {
 367                 wfProfileIn( __METHOD__ );
 368                 global $wgMaxMsgCacheEntrySize, $wgLanguageCode, $wgAdaptiveMessageCache;
 369                 $dbr = wfGetDB( DB_SLAVE );
 370                 $cache = array();
 371
 372                 # Common conditions
 373                 $conds = array(
 374                         'page_is_redirect' => 0,
 375                         'page_namespace' => NS_MEDIAWIKI,
 376                 );
 377
 378                 $mostused = array();
 379                 if ( $wgAdaptiveMessageCache ) {
 380                         $mostused = $this->getMostUsedMessages();
 381                         if ( $code !== $wgLanguageCode ) {
 382                                 foreach ( $mostused as $key => $value ) {
 383                                         $mostused[$key] = "$value/$code";
 384                                 }
 385                         }
 386                 }
 387
 388                 if ( count( $mostused ) ) {
 389                         $conds['page_title'] = $mostused;
 390                 } elseif ( $code !== $wgLanguageCode ) {
 391                         $conds[] = 'page_title' . $dbr->buildLike( $dbr->anyString(), "/$code" );
 392                 } else {
 393                         # Effectively disallows use of '/' character in NS_MEDIAWIKI for uses
 394                         # other than language code.
 395                         $conds[] = 'page_title NOT' . $dbr->buildLike( $dbr->anyString(), '/', $dbr->anyString() );
 396                 }
 397
 398                 # Conditions to fetch oversized pages to ignore them
 399                 $bigConds = $conds;
 400                 $bigConds[] = 'page_len > ' . intval( $wgMaxMsgCacheEntrySize );
 401
 402                 # Load titles for all oversized pages in the MediaWiki namespace
 403                 $res = $dbr->select( 'page', 'page_title', $bigConds, __METHOD__ . "($code)-big" );
 404                 foreach ( $res as $row ) {
 405                         $cache[$row->page_title] = '!TOO BIG';
 406                 }
 407
 408                 # Conditions to load the remaining pages with their contents
 409                 $smallConds = $conds;
 410                 $smallConds[] = 'page_latest=rev_id';
 411                 $smallConds[] = 'rev_text_id=old_id';
 412                 $smallConds[] = 'page_len <= ' . intval( $wgMaxMsgCacheEntrySize );
 413
 414                 $res = $dbr->select(
 415                         array( 'page', 'revision', 'text' ),
 416                         array( 'page_title', 'old_text', 'old_flags' ),
 417                         $smallConds,
 418                         __METHOD__ . "($code)-small"
 419                 );
 420
 421                 foreach ( $res as $row ) {
 422                         $cache[$row->page_title] = ' ' . Revision::getRevisionText( $row );
 423                 }
 424
 425                 foreach ( $mostused as $key ) {
 426                         if ( !isset( $cache[$key] ) ) {
 427                                 $cache[$key] = '!NONEXISTENT';
 428                         }
 429                 }
 430
 431                 $cache['VERSION'] = MSG_CACHE_VERSION;
 432                 wfProfileOut( __METHOD__ );
 433                 return $cache;
 434         }
 435
 436         /**
 437          * Updates cache as necessary when message page is changed
 438          *
 439          * @param $title String: name of the page changed.
 440          * @param $text Mixed: new contents of the page.
 441          */
 442         public function replace( $title, $text ) {
 443                 global $wgMaxMsgCacheEntrySize;
 444                 wfProfileIn( __METHOD__ );
 445
 446                 if ( $this->mDisable ) {
 447                         wfProfileOut( __METHOD__ );
 448                         return;
 449                 }
 450
 451                 list( $msg, $code ) = $this->figureMessage( $title );
 452
 453                 $cacheKey = wfMemcKey( 'messages', $code );
 454                 $this->load( $code );
 455                 $this->lock( $cacheKey );
 456
 457                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 458
 459                 if ( $text === false ) {
 460                         # Article was deleted
 461                         $this->mCache[$code][$title] = '!NONEXISTENT';
 462                         $this->mMemc->delete( $titleKey );
 463                 } elseif ( strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
 464                         # Check for size
 465                         $this->mCache[$code][$title] = '!TOO BIG';
 466                         $this->mMemc->set( $titleKey, ' ' . $text, $this->mExpiry );
 467                 } else {
 468                         $this->mCache[$code][$title] = ' ' . $text;
 469                         $this->mMemc->delete( $titleKey );
 470                 }
 471
 472                 # Update caches
 473                 $this->saveToCaches( $this->mCache[$code], true, $code );
 474                 $this->unlock( $cacheKey );
 475
 476                 // Also delete cached sidebar... just in case it is affected
 477                 $codes = array( $code );
 478                 if ( $code === 'en'  ) {
 479                         // Delete all sidebars, like for example on action=purge on the
 480                         // sidebar messages
 481                         $codes = array_keys( Language::getLanguageNames() );
 482                 }
 483
 484                 global $parserMemc;
 485                 foreach ( $codes as $code ) {
 486                         $sidebarKey = wfMemcKey( 'sidebar', $code );
 487                         $parserMemc->delete( $sidebarKey );
 488                 }
 489
 490                 // Update the message in the message blob store
 491                 global $wgContLang;
 492                 MessageBlobStore::updateMessage( $wgContLang->lcfirst( $msg ) );
 493
 494                 wfRunHooks( 'MessageCacheReplace', array( $title, $text ) );
 495
 496                 wfProfileOut( __METHOD__ );
 497         }
 498
 499         /**
 500          * Shortcut to update caches.
 501          *
 502          * @param $cache Array: cached messages with a version.
 503          * @param $memc Bool: Wether to update or not memcache.
 504          * @param $code String: Language code.
 505          * @return False on somekind of error.
 506          */
 507         protected function saveToCaches( $cache, $memc = true, $code = false ) {
 508                 wfProfileIn( __METHOD__ );
 509                 global $wgUseLocalMessageCache, $wgLocalMessageCacheSerialized;
 510
 511                 $cacheKey = wfMemcKey( 'messages', $code );
 512
 513                 if ( $memc ) {
 514                         $success = $this->mMemc->set( $cacheKey, $cache, $this->mExpiry );
 515                 } else {
 516                         $success = true;
 517                 }
 518
 519                 # Save to local cache
 520                 if ( $wgUseLocalMessageCache ) {
 521                         $serialized = serialize( $cache );
 522                         $hash = md5( $serialized );
 523                         $this->mMemc->set( wfMemcKey( 'messages', $code, 'hash' ), $hash, $this->mExpiry );
 524                         if ($wgLocalMessageCacheSerialized) {
 525                                 $this->saveToLocal( $serialized, $hash, $code );
 526                         } else {
 527                                 $this->saveToScript( $cache, $hash, $code );
 528                         }
 529                 }
 530
 531                 wfProfileOut( __METHOD__ );
 532                 return $success;
 533         }
 534
 535         /**
 536          * Represents a write lock on the messages key
 537          *
 538          * @return Boolean: success
 539          */
 540         function lock( $key ) {
 541                 $lockKey = $key . ':lock';
 542                 for ( $i = 0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 543                         sleep( 1 );
 544                 }
 545
 546                 return $i >= MSG_WAIT_TIMEOUT;
 547         }
 548
 549         function unlock( $key ) {
 550                 $lockKey = $key . ':lock';
 551                 $this->mMemc->delete( $lockKey );
 552         }
 553
 554         /**
 555          * Get a message from either the content language or the user language.
 556          *
 557          * @param $key String: the message cache key
 558          * @param $useDB Boolean: get the message from the DB, false to use only
 559          *               the localisation
 560          * @param $langcode String: code of the language to get the message for, if
 561          *                  it is a valid code create a language for that language,
 562          *                  if it is a string but not a valid code then make a basic
 563          *                  language object, if it is a false boolean then use the
 564          *                  current users language (as a fallback for the old
 565          *                  parameter functionality), or if it is a true boolean
 566          *                  then use the wikis content language (also as a
 567          *                  fallback).
 568          * @param $isFullKey Boolean: specifies whether $key is a two part key
 569          *                   "msg/lang".
 570          */
 571         function get( $key, $useDB = true, $langcode = true, $isFullKey = false ) {
 572                 global $wgLanguageCode, $wgContLang;
 573
 574                 if ( !is_string( $key ) ) {
 575                         throw new MWException( 'Non-string key given' );
 576                 }
 577
 578                 if ( strval( $key ) === '' ) {
 579                         # Shortcut: the empty key is always missing
 580                         return false;
 581                 }
 582
 583                 $lang = wfGetLangObj( $langcode );
 584                 if ( !$lang ) {
 585                         throw new MWException( "Bad lang code $langcode given" );
 586                 }
 587
 588                 $langcode = $lang->getCode();
 589
 590                 $message = false;
 591
 592                 # Normalise title-case input (with some inlining)
 593                 $lckey = str_replace( ' ', '_', $key );
 594                 if ( ord( $key ) < 128 ) {
 595                         $lckey[0] = strtolower( $lckey[0] );
 596                         $uckey = ucfirst( $lckey );
 597                 } else {
 598                         $lckey = $wgContLang->lcfirst( $lckey );
 599                         $uckey = $wgContLang->ucfirst( $lckey );
 600                 }
 601
 602                 /**
 603                  * Record each message request, but only once per request.
 604                  * This information is not used unless $wgAdaptiveMessageCache
 605                  * is enabled.
 606                  */
 607                 $this->mRequestedMessages[$uckey] = true;
 608
 609                 # Try the MediaWiki namespace
 610                 if( !$this->mDisable && $useDB ) {
 611                         $title = $uckey;
 612                         if( !$isFullKey && ( $langcode != $wgLanguageCode ) ) {
 613                                 $title .= '/' . $langcode;
 614                         }
 615                         $message = $this->getMsgFromNamespace( $title, $langcode );
 616                 }
 617
 618                 # Try the array in the language object
 619                 if ( $message === false ) {
 620                         $message = $lang->getMessage( $lckey );
 621                         if ( is_null( $message ) ) {
 622                                 $message = false;
 623                         }
 624                 }
 625
 626                 # Try the array of another language
 627                 if( $message === false ) {
 628                         $parts = explode( '/', $lckey );
 629                         # We may get calls for things that are http-urls from sidebar
 630                         # Let's not load nonexistent languages for those
 631                         # They usually have more than one slash.
 632                         if ( count( $parts ) == 2 && $parts[1] !== '' ) {
 633                                 $message = Language::getMessageFor( $parts[0], $parts[1] );
 634                                 if ( is_null( $message ) ) {
 635                                         $message = false;
 636                                 }
 637                         }
 638                 }
 639
 640                 # Is this a custom message? Try the default language in the db...
 641                 if( ( $message === false || $message === '-' ) &&
 642                         !$this->mDisable && $useDB &&
 643                         !$isFullKey && ( $langcode != $wgLanguageCode ) ) {
 644                         $message = $this->getMsgFromNamespace( $uckey, $wgLanguageCode );
 645                 }
 646
 647                 # Final fallback
 648                 if( $message === false ) {
 649                         return false;
 650                 }
 651
 652                 # Fix whitespace
 653                 $message = strtr( $message,
 654                         array(
 655                                 # Fix for trailing whitespace, removed by textarea
 656                                 '&#32;' => ' ',
 657                                 # Fix for NBSP, converted to space by firefox
 658                                 '&nbsp;' => "\xc2\xa0",
 659                                 '&#160;' => "\xc2\xa0",
 660                         ) );
 661
 662                 return $message;
 663         }
 664
 665         /**
 666          * Get a message from the MediaWiki namespace, with caching. The key must
 667          * first be converted to two-part lang/msg form if necessary.
 668          *
 669          * @param $title String: Message cache key with initial uppercase letter.
 670          * @param $code String: code denoting the language to try.
 671          */
 672         function getMsgFromNamespace( $title, $code ) {
 673                 global $wgAdaptiveMessageCache;
 674
 675                 $this->load( $code );
 676                 if ( isset( $this->mCache[$code][$title] ) ) {
 677                         $entry = $this->mCache[$code][$title];
 678                         if ( substr( $entry, 0, 1 ) === ' ' ) {
 679                                 return substr( $entry, 1 );
 680                         } elseif ( $entry === '!NONEXISTENT' ) {
 681                                 return false;
 682                         } elseif( $entry === '!TOO BIG' ) {
 683                                 // Fall through and try invididual message cache below
 684                         }
 685                 } else {
 686                         // XXX: This is not cached in process cache, should it?
 687                         $message = false;
 688                         wfRunHooks( 'MessagesPreLoad', array( $title, &$message ) );
 689                         if ( $message !== false ) {
 690                                 return $message;
 691                         }
 692
 693                         /**
 694                          * If message cache is in normal mode, it is guaranteed
 695                          * (except bugs) that there is always entry (or placeholder)
 696                          * in the cache if message exists. Thus we can do minor
 697                          * performance improvement and return false early.
 698                          */
 699                         if ( !$wgAdaptiveMessageCache ) {
 700                                 return false;
 701                         }
 702                 }
 703
 704                 # Try the individual message cache
 705                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 706                 $entry = $this->mMemc->get( $titleKey );
 707                 if ( $entry ) {
 708                         if ( substr( $entry, 0, 1 ) === ' ' ) {
 709                                 $this->mCache[$code][$title] = $entry;
 710                                 return substr( $entry, 1 );
 711                         } elseif ( $entry === '!NONEXISTENT' ) {
 712                                 $this->mCache[$code][$title] = '!NONEXISTENT';
 713                                 return false;
 714                         } else {
 715                                 # Corrupt/obsolete entry, delete it
 716                                 $this->mMemc->delete( $titleKey );
 717                         }
 718                 }
 719
 720                 # Try loading it from the database
 721                 $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 722                 if ( $revision ) {
 723                         $message = $revision->getText();
 724                         $this->mCache[$code][$title] = ' ' . $message;
 725                         $this->mMemc->set( $titleKey, ' ' . $message, $this->mExpiry );
 726                 } else {
 727                         $message = false;
 728                         $this->mCache[$code][$title] = '!NONEXISTENT';
 729                         $this->mMemc->set( $titleKey, '!NONEXISTENT', $this->mExpiry );
 730                 }
 731
 732                 return $message;
 733         }
 734
 735         function transform( $message, $interface = false, $language = null, $title = null ) {
 736                 // Avoid creating parser if nothing to transform
 737                 if( strpos( $message, '{{' ) === false ) {
 738                         return $message;
 739                 }
 740
 741                 $parser = $this->getParser();
 742                 if ( $parser ) {
 743                         $popts = $this->getParserOptions();
 744                         $popts->setInterfaceMessage( $interface );
 745                         $popts->setTargetLanguage( $language );
 746                         $popts->setUserLang( $language );
 747                         $message = $parser->transformMsg( $message, $popts, $title );
 748                 }
 749                 return $message;
 750         }
 751
 752         /**
 753          * @return Parser
 754          */
 755         function getParser() {
 756                 global $wgParser, $wgParserConf;
 757                 if ( !$this->mParser && isset( $wgParser ) ) {
 758                         # Do some initialisation so that we don't have to do it twice
 759                         $wgParser->firstCallInit();
 760                         # Clone it and store it
 761                         $class = $wgParserConf['class'];
 762                         if ( $class == 'Parser_DiffTest' ) {
 763                                 # Uncloneable
 764                                 $this->mParser = new $class( $wgParserConf );
 765                         } else {
 766                                 $this->mParser = clone $wgParser;
 767                         }
 768                 }
 769                 return $this->mParser;
 770         }
 771
 772         /**
 773          * @param $text string
 774          * @param $title
 775          * @param $linestart bool
 776          * @return ParserOutput
 777          */
 778         public function parse( $text, $title = null, $linestart = true, $interface = false, $language = null  ) {
 779                 $parser = $this->getParser();
 780                 $popts = $this->getParserOptions();
 781
 782                 if ( $interface ) {
 783                         $popts->setInterfaceMessage( true );
 784                 }
 785                 if ( $language !== null ) {
 786                         $popts->setTargetLanguage( $language );
 787                 }
 788
 789                 return $parser->parse( $text, $title, $popts, $linestart );
 790         }
 791
 792         function disable() {
 793                 $this->mDisable = true;
 794         }
 795
 796         function enable() {
 797                 $this->mDisable = false;
 798         }
 799
 800         /**
 801          * Clear all stored messages. Mainly used after a mass rebuild.
 802          */
 803         function clear() {
 804                 $langs = Language::getLanguageNames( false );
 805                 foreach ( array_keys($langs) as $code ) {
 806                         # Global cache
 807                         $this->mMemc->delete( wfMemcKey( 'messages', $code ) );
 808                         # Invalidate all local caches
 809                         $this->mMemc->delete( wfMemcKey( 'messages', $code, 'hash' ) );
 810                 }
 811                 $this->mLoadedLanguages = array();
 812         }
 813
 814         public function figureMessage( $key ) {
 815                 global $wgLanguageCode;
 816                 $pieces = explode( '/', $key );
 817                 if( count( $pieces ) < 2 ) {
 818                         return array( $key, $wgLanguageCode );
 819                 }
 820
 821                 $lang = array_pop( $pieces );
 822                 $validCodes = Language::getLanguageNames();
 823                 if( !array_key_exists( $lang, $validCodes ) ) {
 824                         return array( $key, $wgLanguageCode );
 825                 }
 826
 827                 $message = implode( '/', $pieces );
 828                 return array( $message, $lang );
 829         }
 830
 831         public static function logMessages() {
 832                 wfProfileIn( __METHOD__ );
 833                 global $wgAdaptiveMessageCache;
 834                 if ( !$wgAdaptiveMessageCache || !self::$instance instanceof MessageCache ) {
 835                         wfProfileOut( __METHOD__ );
 836                         return;
 837                 }
 838
 839                 $cachekey = wfMemckey( 'message-profiling' );
 840                 $cache = wfGetCache( CACHE_DB );
 841                 $data = $cache->get( $cachekey );
 842
 843                 if ( !$data ) {
 844                         $data = array();
 845                 }
 846
 847                 $age = self::$mAdaptiveDataAge;
 848                 $filterDate = substr( wfTimestamp( TS_MW, time() - $age ), 0, 8 );
 849                 foreach ( array_keys( $data ) as $key ) {
 850                         if ( $key < $filterDate ) {
 851                                 unset( $data[$key] );
 852                         }
 853                 }
 854
 855                 $index = substr( wfTimestampNow(), 0, 8 );
 856                 if ( !isset( $data[$index] ) ) {
 857                         $data[$index] = array();
 858                 }
 859
 860                 foreach ( self::$instance->mRequestedMessages as $message => $_ ) {
 861                         if ( !isset( $data[$index][$message] ) ) {
 862                                 $data[$index][$message] = 0;
 863                         }
 864                         $data[$index][$message]++;
 865                 }
 866
 867                 $cache->set( $cachekey, $data );
 868                 wfProfileOut( __METHOD__ );
 869         }
 870
 871         public function getMostUsedMessages() {
 872                 wfProfileIn( __METHOD__ );
 873                 $cachekey = wfMemcKey( 'message-profiling' );
 874                 $cache = wfGetCache( CACHE_DB );
 875                 $data = $cache->get( $cachekey );
 876                 if ( !$data ) {
 877                         wfProfileOut( __METHOD__ );
 878                         return array();
 879                 }
 880
 881                 $list = array();
 882
 883                 foreach( $data as $messages ) {
 884                         foreach( $messages as $message => $count ) {
 885                                 $key = $message;
 886                                 if ( !isset( $list[$key] ) ) {
 887                                         $list[$key] = 0;
 888                                 }
 889                                 $list[$key] += $count;
 890                         }
 891                 }
 892
 893                 $max = max( $list );
 894                 foreach ( $list as $message => $count ) {
 895                         if ( $count < intval( $max * self::$mAdaptiveInclusionThreshold ) ) {
 896                                 unset( $list[$message] );
 897                         }
 898                 }
 899
 900                 wfProfileOut( __METHOD__ );
 901                 return array_keys( $list );
 902         }
 903
 904 }