includes/cache/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          * @var MessageCache
  69          */
  70         private static $instance;
  71
  72         /**
  73          * @var bool
  74          */
  75         protected $mInParser = false;
  76
  77         /**
  78          * Get the signleton instance of this class
  79          *
  80          * @since 1.18
  81          * @return MessageCache object
  82          */
  83         public static function singleton() {
  84                 if ( is_null( self::$instance ) ) {
  85                         global $wgUseDatabaseMessages, $wgMsgCacheExpiry;
  86                         self::$instance = new self( wfGetMessageCacheStorage(), $wgUseDatabaseMessages, $wgMsgCacheExpiry );
  87                 }
  88                 return self::$instance;
  89         }
  90
  91         /**
  92          * Destroy the singleton instance
  93          *
  94          * @since 1.18
  95          */
  96         public static function destroyInstance() {
  97                 self::$instance = null;
  98         }
  99
 100         function __construct( $memCached, $useDB, $expiry ) {
 101                 if ( !$memCached ) {
 102                         $memCached = wfGetCache( CACHE_NONE );
 103                 }
 104
 105                 $this->mMemc = $memCached;
 106                 $this->mDisable = !$useDB;
 107                 $this->mExpiry = $expiry;
 108         }
 109
 110         /**
 111          * ParserOptions is lazy initialised.
 112          *
 113          * @return ParserOptions
 114          */
 115         function getParserOptions() {
 116                 if ( !$this->mParserOptions ) {
 117                         $this->mParserOptions = new ParserOptions;
 118                 }
 119                 return $this->mParserOptions;
 120         }
 121
 122         /**
 123          * Try to load the cache from a local file.
 124          * Actual format of the file depends on the $wgLocalMessageCacheSerialized
 125          * setting.
 126          *
 127          * @param $hash String: the hash of contents, to check validity.
 128          * @param $code Mixed: Optional language code, see documenation of load().
 129          * @return false on failure.
 130          */
 131         function loadFromLocal( $hash, $code ) {
 132                 global $wgCacheDirectory, $wgLocalMessageCacheSerialized;
 133
 134                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 135
 136                 # Check file existence
 137                 wfSuppressWarnings();
 138                 $file = fopen( $filename, 'r' );
 139                 wfRestoreWarnings();
 140                 if ( !$file ) {
 141                         return false; // No cache file
 142                 }
 143
 144                 if ( $wgLocalMessageCacheSerialized ) {
 145                         // Check to see if the file has the hash specified
 146                         $localHash = fread( $file, 32 );
 147                         if ( $hash === $localHash ) {
 148                                 // All good, get the rest of it
 149                                 $serialized = '';
 150                                 while ( !feof( $file ) ) {
 151                                         $serialized .= fread( $file, 100000 );
 152                                 }
 153                                 fclose( $file );
 154                                 return $this->setCache( unserialize( $serialized ), $code );
 155                         } else {
 156                                 fclose( $file );
 157                                 return false; // Wrong hash
 158                         }
 159                 } else {
 160                         $localHash = substr( fread( $file, 40 ), 8 );
 161                         fclose( $file );
 162                         if ( $hash != $localHash ) {
 163                                 return false; // Wrong hash
 164                         }
 165
 166                         # Require overwrites the member variable or just shadows it?
 167                         require( $filename );
 168                         return $this->setCache( $this->mCache, $code );
 169                 }
 170         }
 171
 172         /**
 173          * Save the cache to a local file.
 174          */
 175         function saveToLocal( $serialized, $hash, $code ) {
 176                 global $wgCacheDirectory;
 177
 178                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 179                 wfMkdirParents( $wgCacheDirectory ); // might fail
 180
 181                 wfSuppressWarnings();
 182                 $file = fopen( $filename, 'w' );
 183                 wfRestoreWarnings();
 184
 185                 if ( !$file ) {
 186                         wfDebug( "Unable to open local cache file for writing\n" );
 187                         return;
 188                 }
 189
 190                 fwrite( $file, $hash . $serialized );
 191                 fclose( $file );
 192                 wfSuppressWarnings();
 193                 chmod( $filename, 0666 );
 194                 wfRestoreWarnings();
 195         }
 196
 197         function saveToScript( $array, $hash, $code ) {
 198                 global $wgCacheDirectory;
 199
 200                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 201                 $tempFilename = $filename . '.tmp';
 202                 wfMkdirParents( $wgCacheDirectory ); // might fail
 203
 204                 wfSuppressWarnings();
 205                 $file = fopen( $tempFilename, 'w' );
 206                 wfRestoreWarnings();
 207
 208                 if ( !$file ) {
 209                         wfDebug( "Unable to open local cache file for writing\n" );
 210                         return;
 211                 }
 212
 213                 fwrite( $file, "<?php\n//$hash\n\n \$this->mCache = array(" );
 214
 215                 foreach ( $array as $key => $message ) {
 216                         $key = $this->escapeForScript( $key );
 217                         $message = $this->escapeForScript( $message );
 218                         fwrite( $file, "'$key' => '$message',\n" );
 219                 }
 220
 221                 fwrite( $file, ");\n?>" );
 222                 fclose( $file);
 223                 rename( $tempFilename, $filename );
 224         }
 225
 226         function escapeForScript( $string ) {
 227                 $string = str_replace( '\\', '\\\\', $string );
 228                 $string = str_replace( '\'', '\\\'', $string );
 229                 return $string;
 230         }
 231
 232         /**
 233          * Set the cache to $cache, if it is valid. Otherwise set the cache to false.
 234          *
 235          * @return bool
 236          */
 237         function setCache( $cache, $code ) {
 238                 if ( isset( $cache['VERSION'] ) && $cache['VERSION'] == MSG_CACHE_VERSION ) {
 239                         $this->mCache[$code] = $cache;
 240                         return true;
 241                 } else {
 242                         return false;
 243                 }
 244         }
 245
 246         /**
 247          * Loads messages from caches or from database in this order:
 248          * (1) local message cache (if $wgUseLocalMessageCache is enabled)
 249          * (2) memcached
 250          * (3) from the database.
 251          *
 252          * When succesfully loading from (2) or (3), all higher level caches are
 253          * updated for the newest version.
 254          *
 255          * Nothing is loaded if member variable mDisable is true, either manually
 256          * set by calling code or if message loading fails (is this possible?).
 257          *
 258          * Returns true if cache is already populated or it was succesfully populated,
 259          * or false if populating empty cache fails. Also returns true if MessageCache
 260          * is disabled.
 261          *
 262          * @param $code String: language to which load messages
 263          */
 264         function load( $code = false ) {
 265                 global $wgUseLocalMessageCache;
 266
 267                 if( !is_string( $code ) ) {
 268                         # This isn't really nice, so at least make a note about it and try to
 269                         # fall back
 270                         wfDebug( __METHOD__ . " called without providing a language code\n" );
 271                         $code = 'en';
 272                 }
 273
 274                 # Don't do double loading...
 275                 if ( isset( $this->mLoadedLanguages[$code] ) ) {
 276                         return true;
 277                 }
 278
 279                 # 8 lines of code just to say (once) that message cache is disabled
 280                 if ( $this->mDisable ) {
 281                         static $shownDisabled = false;
 282                         if ( !$shownDisabled ) {
 283                                 wfDebug( __METHOD__ . ": disabled\n" );
 284                                 $shownDisabled = true;
 285                         }
 286                         return true;
 287                 }
 288
 289                 # Loading code starts
 290                 wfProfileIn( __METHOD__ );
 291                 $success = false; # Keep track of success
 292                 $where = array(); # Debug info, delayed to avoid spamming debug log too much
 293                 $cacheKey = wfMemcKey( 'messages', $code ); # Key in memc for messages
 294
 295                 # (1) local cache
 296                 # Hash of the contents is stored in memcache, to detect if local cache goes
 297                 # out of date (due to update in other thread?)
 298                 if ( $wgUseLocalMessageCache ) {
 299                         wfProfileIn( __METHOD__ . '-fromlocal' );
 300
 301                         $hash = $this->mMemc->get( wfMemcKey( 'messages', $code, 'hash' ) );
 302                         if ( $hash ) {
 303                                 $success = $this->loadFromLocal( $hash, $code );
 304                                 if ( $success ) $where[] = 'got from local cache';
 305                         }
 306                         wfProfileOut( __METHOD__ . '-fromlocal' );
 307                 }
 308
 309                 # (2) memcache
 310                 # Fails if nothing in cache, or in the wrong version.
 311                 if ( !$success ) {
 312                         wfProfileIn( __METHOD__ . '-fromcache' );
 313                         $cache = $this->mMemc->get( $cacheKey );
 314                         $success = $this->setCache( $cache, $code );
 315                         if ( $success ) {
 316                                 $where[] = 'got from global cache';
 317                                 $this->saveToCaches( $cache, false, $code );
 318                         }
 319                         wfProfileOut( __METHOD__ . '-fromcache' );
 320                 }
 321
 322                 # (3)
 323                 # Nothing in caches... so we need create one and store it in caches
 324                 if ( !$success ) {
 325                         $where[] = 'cache is empty';
 326                         $where[] = 'loading from database';
 327
 328                         $this->lock( $cacheKey );
 329
 330                         # Limit the concurrency of loadFromDB to a single process
 331                         # This prevents the site from going down when the cache expires
 332                         $statusKey = wfMemcKey( 'messages', $code, 'status' );
 333                         $success = $this->mMemc->add( $statusKey, 'loading', MSG_LOAD_TIMEOUT );
 334                         if ( $success ) {
 335                                 $cache = $this->loadFromDB( $code );
 336                                 $success = $this->setCache( $cache, $code );
 337                         }
 338                         if ( $success ) {
 339                                 $success = $this->saveToCaches( $cache, true, $code );
 340                                 if ( $success ) {
 341                                         $this->mMemc->delete( $statusKey );
 342                                 } else {
 343                                         $this->mMemc->set( $statusKey, 'error', 60 * 5 );
 344                                         wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 345                                 }
 346                         }
 347                         $this->unlock($cacheKey);
 348                 }
 349
 350                 if ( !$success ) {
 351                         # Bad luck... this should not happen
 352                         $where[] = 'loading FAILED - cache is disabled';
 353                         $info = implode( ', ', $where );
 354                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 355                         $this->mDisable = true;
 356                         $this->mCache = false;
 357                 } else {
 358                         # All good, just record the success
 359                         $info = implode( ', ', $where );
 360                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 361                         $this->mLoadedLanguages[$code] = true;
 362                 }
 363                 wfProfileOut( __METHOD__ );
 364                 return $success;
 365         }
 366
 367         /**
 368          * Loads cacheable messages from the database. Messages bigger than
 369          * $wgMaxMsgCacheEntrySize are assigned a special value, and are loaded
 370          * on-demand from the database later.
 371          *
 372          * @param $code String: language code.
 373          * @return Array: loaded messages for storing in caches.
 374          */
 375         function loadFromDB( $code ) {
 376                 wfProfileIn( __METHOD__ );
 377                 global $wgMaxMsgCacheEntrySize, $wgLanguageCode, $wgAdaptiveMessageCache;
 378                 $dbr = wfGetDB( DB_SLAVE );
 379                 $cache = array();
 380
 381                 # Common conditions
 382                 $conds = array(
 383                         'page_is_redirect' => 0,
 384                         'page_namespace' => NS_MEDIAWIKI,
 385                 );
 386
 387                 $mostused = array();
 388                 if ( $wgAdaptiveMessageCache ) {
 389                         $mostused = $this->getMostUsedMessages();
 390                         if ( $code !== $wgLanguageCode ) {
 391                                 foreach ( $mostused as $key => $value ) {
 392                                         $mostused[$key] = "$value/$code";
 393                                 }
 394                         }
 395                 }
 396
 397                 if ( count( $mostused ) ) {
 398                         $conds['page_title'] = $mostused;
 399                 } elseif ( $code !== $wgLanguageCode ) {
 400                         $conds[] = 'page_title' . $dbr->buildLike( $dbr->anyString(), "/$code" );
 401                 } else {
 402                         # Effectively disallows use of '/' character in NS_MEDIAWIKI for uses
 403                         # other than language code.
 404                         $conds[] = 'page_title NOT' . $dbr->buildLike( $dbr->anyString(), '/', $dbr->anyString() );
 405                 }
 406
 407                 # Conditions to fetch oversized pages to ignore them
 408                 $bigConds = $conds;
 409                 $bigConds[] = 'page_len > ' . intval( $wgMaxMsgCacheEntrySize );
 410
 411                 # Load titles for all oversized pages in the MediaWiki namespace
 412                 $res = $dbr->select( 'page', 'page_title', $bigConds, __METHOD__ . "($code)-big" );
 413                 foreach ( $res as $row ) {
 414                         $cache[$row->page_title] = '!TOO BIG';
 415                 }
 416
 417                 # Conditions to load the remaining pages with their contents
 418                 $smallConds = $conds;
 419                 $smallConds[] = 'page_latest=rev_id';
 420                 $smallConds[] = 'rev_text_id=old_id';
 421                 $smallConds[] = 'page_len <= ' . intval( $wgMaxMsgCacheEntrySize );
 422
 423                 $res = $dbr->select(
 424                         array( 'page', 'revision', 'text' ),
 425                         array( 'page_title', 'old_text', 'old_flags' ),
 426                         $smallConds,
 427                         __METHOD__ . "($code)-small"
 428                 );
 429
 430                 foreach ( $res as $row ) {
 431                         $cache[$row->page_title] = ' ' . Revision::getRevisionText( $row );
 432                 }
 433
 434                 foreach ( $mostused as $key ) {
 435                         if ( !isset( $cache[$key] ) ) {
 436                                 $cache[$key] = '!NONEXISTENT';
 437                         }
 438                 }
 439
 440                 $cache['VERSION'] = MSG_CACHE_VERSION;
 441                 wfProfileOut( __METHOD__ );
 442                 return $cache;
 443         }
 444
 445         /**
 446          * Updates cache as necessary when message page is changed
 447          *
 448          * @param $title String: name of the page changed.
 449          * @param $text Mixed: new contents of the page.
 450          */
 451         public function replace( $title, $text ) {
 452                 global $wgMaxMsgCacheEntrySize;
 453                 wfProfileIn( __METHOD__ );
 454
 455                 if ( $this->mDisable ) {
 456                         wfProfileOut( __METHOD__ );
 457                         return;
 458                 }
 459
 460                 list( $msg, $code ) = $this->figureMessage( $title );
 461
 462                 $cacheKey = wfMemcKey( 'messages', $code );
 463                 $this->load( $code );
 464                 $this->lock( $cacheKey );
 465
 466                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 467
 468                 if ( $text === false ) {
 469                         # Article was deleted
 470                         $this->mCache[$code][$title] = '!NONEXISTENT';
 471                         $this->mMemc->delete( $titleKey );
 472                 } elseif ( strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
 473                         # Check for size
 474                         $this->mCache[$code][$title] = '!TOO BIG';
 475                         $this->mMemc->set( $titleKey, ' ' . $text, $this->mExpiry );
 476                 } else {
 477                         $this->mCache[$code][$title] = ' ' . $text;
 478                         $this->mMemc->delete( $titleKey );
 479                 }
 480
 481                 # Update caches
 482                 $this->saveToCaches( $this->mCache[$code], true, $code );
 483                 $this->unlock( $cacheKey );
 484
 485                 // Also delete cached sidebar... just in case it is affected
 486                 $codes = array( $code );
 487                 if ( $code === 'en'  ) {
 488                         // Delete all sidebars, like for example on action=purge on the
 489                         // sidebar messages
 490                         $codes = array_keys( Language::getLanguageNames() );
 491                 }
 492
 493                 global $parserMemc;
 494                 foreach ( $codes as $code ) {
 495                         $sidebarKey = wfMemcKey( 'sidebar', $code );
 496                         $parserMemc->delete( $sidebarKey );
 497                 }
 498
 499                 // Update the message in the message blob store
 500                 global $wgContLang;
 501                 MessageBlobStore::updateMessage( $wgContLang->lcfirst( $msg ) );
 502
 503                 wfRunHooks( 'MessageCacheReplace', array( $title, $text ) );
 504
 505                 wfProfileOut( __METHOD__ );
 506         }
 507
 508         /**
 509          * Shortcut to update caches.
 510          *
 511          * @param $cache Array: cached messages with a version.
 512          * @param $memc Bool: Wether to update or not memcache.
 513          * @param $code String: Language code.
 514          * @return False on somekind of error.
 515          */
 516         protected function saveToCaches( $cache, $memc = true, $code = false ) {
 517                 wfProfileIn( __METHOD__ );
 518                 global $wgUseLocalMessageCache, $wgLocalMessageCacheSerialized;
 519
 520                 $cacheKey = wfMemcKey( 'messages', $code );
 521
 522                 if ( $memc ) {
 523                         $success = $this->mMemc->set( $cacheKey, $cache, $this->mExpiry );
 524                 } else {
 525                         $success = true;
 526                 }
 527
 528                 # Save to local cache
 529                 if ( $wgUseLocalMessageCache ) {
 530                         $serialized = serialize( $cache );
 531                         $hash = md5( $serialized );
 532                         $this->mMemc->set( wfMemcKey( 'messages', $code, 'hash' ), $hash, $this->mExpiry );
 533                         if ($wgLocalMessageCacheSerialized) {
 534                                 $this->saveToLocal( $serialized, $hash, $code );
 535                         } else {
 536                                 $this->saveToScript( $cache, $hash, $code );
 537                         }
 538                 }
 539
 540                 wfProfileOut( __METHOD__ );
 541                 return $success;
 542         }
 543
 544         /**
 545          * Represents a write lock on the messages key
 546          *
 547          * @return Boolean: success
 548          */
 549         function lock( $key ) {
 550                 $lockKey = $key . ':lock';
 551                 for ( $i = 0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 552                         sleep( 1 );
 553                 }
 554
 555                 return $i >= MSG_WAIT_TIMEOUT;
 556         }
 557
 558         function unlock( $key ) {
 559                 $lockKey = $key . ':lock';
 560                 $this->mMemc->delete( $lockKey );
 561         }
 562
 563         /**
 564          * Get a message from either the content language or the user language.
 565          *
 566          * @param $key String: the message cache key
 567          * @param $useDB Boolean: get the message from the DB, false to use only
 568          *               the localisation
 569          * @param $langcode String: code of the language to get the message for, if
 570          *                  it is a valid code create a language for that language,
 571          *                  if it is a string but not a valid code then make a basic
 572          *                  language object, if it is a false boolean then use the
 573          *                  current users language (as a fallback for the old
 574          *                  parameter functionality), or if it is a true boolean
 575          *                  then use the wikis content language (also as a
 576          *                  fallback).
 577          * @param $isFullKey Boolean: specifies whether $key is a two part key
 578          *                   "msg/lang".
 579          */
 580         function get( $key, $useDB = true, $langcode = true, $isFullKey = false ) {
 581                 global $wgLanguageCode, $wgContLang;
 582
 583                 if ( !is_string( $key ) ) {
 584                         throw new MWException( 'Non-string key given' );
 585                 }
 586
 587                 if ( strval( $key ) === '' ) {
 588                         # Shortcut: the empty key is always missing
 589                         return false;
 590                 }
 591
 592                 $lang = wfGetLangObj( $langcode );
 593                 if ( !$lang ) {
 594                         throw new MWException( "Bad lang code $langcode given" );
 595                 }
 596
 597                 $langcode = $lang->getCode();
 598
 599                 $message = false;
 600
 601                 # Normalise title-case input (with some inlining)
 602                 $lckey = str_replace( ' ', '_', $key );
 603                 if ( ord( $key ) < 128 ) {
 604                         $lckey[0] = strtolower( $lckey[0] );
 605                         $uckey = ucfirst( $lckey );
 606                 } else {
 607                         $lckey = $wgContLang->lcfirst( $lckey );
 608                         $uckey = $wgContLang->ucfirst( $lckey );
 609                 }
 610
 611                 /**
 612                  * Record each message request, but only once per request.
 613                  * This information is not used unless $wgAdaptiveMessageCache
 614                  * is enabled.
 615                  */
 616                 $this->mRequestedMessages[$uckey] = true;
 617
 618                 # Try the MediaWiki namespace
 619                 if( !$this->mDisable && $useDB ) {
 620                         $title = $uckey;
 621                         if( !$isFullKey && ( $langcode != $wgLanguageCode ) ) {
 622                                 $title .= '/' . $langcode;
 623                         }
 624                         $message = $this->getMsgFromNamespace( $title, $langcode );
 625                 }
 626
 627                 # Try the array in the language object
 628                 if ( $message === false ) {
 629                         $message = $lang->getMessage( $lckey );
 630                         if ( is_null( $message ) ) {
 631                                 $message = false;
 632                         }
 633                 }
 634
 635                 # Try the array of another language
 636                 if( $message === false ) {
 637                         $parts = explode( '/', $lckey );
 638                         # We may get calls for things that are http-urls from sidebar
 639                         # Let's not load nonexistent languages for those
 640                         # They usually have more than one slash.
 641                         if ( count( $parts ) == 2 && $parts[1] !== '' ) {
 642                                 $message = Language::getMessageFor( $parts[0], $parts[1] );
 643                                 if ( is_null( $message ) ) {
 644                                         $message = false;
 645                                 }
 646                         }
 647                 }
 648
 649                 # Is this a custom message? Try the default language in the db...
 650                 if( ( $message === false || $message === '-' ) &&
 651                         !$this->mDisable && $useDB &&
 652                         !$isFullKey && ( $langcode != $wgLanguageCode ) ) {
 653                         $message = $this->getMsgFromNamespace( $uckey, $wgLanguageCode );
 654                 }
 655
 656                 # Final fallback
 657                 if( $message === false ) {
 658                         return false;
 659                 }
 660
 661                 # Fix whitespace
 662                 $message = strtr( $message,
 663                         array(
 664                                 # Fix for trailing whitespace, removed by textarea
 665                                 '&#32;' => ' ',
 666                                 # Fix for NBSP, converted to space by firefox
 667                                 '&nbsp;' => "\xc2\xa0",
 668                                 '&#160;' => "\xc2\xa0",
 669                         ) );
 670
 671                 return $message;
 672         }
 673
 674         /**
 675          * Get a message from the MediaWiki namespace, with caching. The key must
 676          * first be converted to two-part lang/msg form if necessary.
 677          *
 678          * @param $title String: Message cache key with initial uppercase letter.
 679          * @param $code String: code denoting the language to try.
 680          */
 681         function getMsgFromNamespace( $title, $code ) {
 682                 global $wgAdaptiveMessageCache;
 683
 684                 $this->load( $code );
 685                 if ( isset( $this->mCache[$code][$title] ) ) {
 686                         $entry = $this->mCache[$code][$title];
 687                         if ( substr( $entry, 0, 1 ) === ' ' ) {
 688                                 return substr( $entry, 1 );
 689                         } elseif ( $entry === '!NONEXISTENT' ) {
 690                                 return false;
 691                         } elseif( $entry === '!TOO BIG' ) {
 692                                 // Fall through and try invididual message cache below
 693                         }
 694                 } else {
 695                         // XXX: This is not cached in process cache, should it?
 696                         $message = false;
 697                         wfRunHooks( 'MessagesPreLoad', array( $title, &$message ) );
 698                         if ( $message !== false ) {
 699                                 return $message;
 700                         }
 701
 702                         /**
 703                          * If message cache is in normal mode, it is guaranteed
 704                          * (except bugs) that there is always entry (or placeholder)
 705                          * in the cache if message exists. Thus we can do minor
 706                          * performance improvement and return false early.
 707                          */
 708                         if ( !$wgAdaptiveMessageCache ) {
 709                                 return false;
 710                         }
 711                 }
 712
 713                 # Try the individual message cache
 714                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 715                 $entry = $this->mMemc->get( $titleKey );
 716                 if ( $entry ) {
 717                         if ( substr( $entry, 0, 1 ) === ' ' ) {
 718                                 $this->mCache[$code][$title] = $entry;
 719                                 return substr( $entry, 1 );
 720                         } elseif ( $entry === '!NONEXISTENT' ) {
 721                                 $this->mCache[$code][$title] = '!NONEXISTENT';
 722                                 return false;
 723                         } else {
 724                                 # Corrupt/obsolete entry, delete it
 725                                 $this->mMemc->delete( $titleKey );
 726                         }
 727                 }
 728
 729                 # Try loading it from the database
 730                 $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 731                 if ( $revision ) {
 732                         $message = $revision->getText();
 733                         $this->mCache[$code][$title] = ' ' . $message;
 734                         $this->mMemc->set( $titleKey, ' ' . $message, $this->mExpiry );
 735                 } else {
 736                         $message = false;
 737                         $this->mCache[$code][$title] = '!NONEXISTENT';
 738                         $this->mMemc->set( $titleKey, '!NONEXISTENT', $this->mExpiry );
 739                 }
 740
 741                 return $message;
 742         }
 743
 744         /**
 745          * @param $message string
 746          * @param $interface bool
 747          * @param $language
 748          * @param $title Title
 749          * @return string
 750          */
 751         function transform( $message, $interface = false, $language = null, $title = null ) {
 752                 // Avoid creating parser if nothing to transform
 753                 if( strpos( $message, '{{' ) === false ) {
 754                         return $message;
 755                 }
 756
 757                 if ( $this->mInParser ) {
 758                         return $message;
 759                 }
 760
 761                 $parser = $this->getParser();
 762                 if ( $parser ) {
 763                         $popts = $this->getParserOptions();
 764                         $popts->setInterfaceMessage( $interface );
 765                         $popts->setTargetLanguage( $language );
 766
 767                         $userlang = $popts->setUserLang( $language );
 768                         $this->mInParser = true;
 769                         $message = $parser->transformMsg( $message, $popts, $title );
 770                         $this->mInParser = false;
 771                         $popts->setUserLang( $userlang );
 772                 }
 773                 return $message;
 774         }
 775
 776         /**
 777          * @return Parser
 778          */
 779         function getParser() {
 780                 global $wgParser, $wgParserConf;
 781                 if ( !$this->mParser && isset( $wgParser ) ) {
 782                         # Do some initialisation so that we don't have to do it twice
 783                         $wgParser->firstCallInit();
 784                         # Clone it and store it
 785                         $class = $wgParserConf['class'];
 786                         if ( $class == 'Parser_DiffTest' ) {
 787                                 # Uncloneable
 788                                 $this->mParser = new $class( $wgParserConf );
 789                         } else {
 790                                 $this->mParser = clone $wgParser;
 791                         }
 792                 }
 793                 return $this->mParser;
 794         }
 795
 796         /**
 797          * @param $text string
 798          * @param $string Title|string
 799          * @param $title Title
 800          * @param $interface bool
 801          * @param $linestart bool
 802          * @param $language
 803          * @return ParserOutput
 804          */
 805         public function parse( $text, $title = null, $linestart = true, $interface = false, $language = null  ) {
 806                 if ( $this->mInParser ) {
 807                         return htmlspecialchars( $text );
 808                 }
 809
 810                 $parser = $this->getParser();
 811                 $popts = $this->getParserOptions();
 812
 813                 if ( $interface ) {
 814                         $popts->setInterfaceMessage( true );
 815                 }
 816                 if ( $language !== null ) {
 817                         $popts->setTargetLanguage( $language );
 818                 }
 819
 820                 if ( !$title || !$title instanceof Title ) {
 821                         global $wgTitle;
 822                         $title = $wgTitle;
 823                 }
 824
 825                 $this->mInParser = true;
 826                 $res = $parser->parse( $text, $title, $popts, $linestart );
 827                 $this->mInParser = false;
 828
 829                 return $res;
 830         }
 831
 832         function disable() {
 833                 $this->mDisable = true;
 834         }
 835
 836         function enable() {
 837                 $this->mDisable = false;
 838         }
 839
 840         /**
 841          * Clear all stored messages. Mainly used after a mass rebuild.
 842          */
 843         function clear() {
 844                 $langs = Language::getLanguageNames( false );
 845                 foreach ( array_keys($langs) as $code ) {
 846                         # Global cache
 847                         $this->mMemc->delete( wfMemcKey( 'messages', $code ) );
 848                         # Invalidate all local caches
 849                         $this->mMemc->delete( wfMemcKey( 'messages', $code, 'hash' ) );
 850                 }
 851                 $this->mLoadedLanguages = array();
 852         }
 853
 854         public function figureMessage( $key ) {
 855                 global $wgLanguageCode;
 856                 $pieces = explode( '/', $key );
 857                 if( count( $pieces ) < 2 ) {
 858                         return array( $key, $wgLanguageCode );
 859                 }
 860
 861                 $lang = array_pop( $pieces );
 862                 $validCodes = Language::getLanguageNames();
 863                 if( !array_key_exists( $lang, $validCodes ) ) {
 864                         return array( $key, $wgLanguageCode );
 865                 }
 866
 867                 $message = implode( '/', $pieces );
 868                 return array( $message, $lang );
 869         }
 870
 871         public static function logMessages() {
 872                 wfProfileIn( __METHOD__ );
 873                 global $wgAdaptiveMessageCache;
 874                 if ( !$wgAdaptiveMessageCache || !self::$instance instanceof MessageCache ) {
 875                         wfProfileOut( __METHOD__ );
 876                         return;
 877                 }
 878
 879                 $cachekey = wfMemckey( 'message-profiling' );
 880                 $cache = wfGetCache( CACHE_DB );
 881                 $data = $cache->get( $cachekey );
 882
 883                 if ( !$data ) {
 884                         $data = array();
 885                 }
 886
 887                 $age = self::$mAdaptiveDataAge;
 888                 $filterDate = substr( wfTimestamp( TS_MW, time() - $age ), 0, 8 );
 889                 foreach ( array_keys( $data ) as $key ) {
 890                         if ( $key < $filterDate ) {
 891                                 unset( $data[$key] );
 892                         }
 893                 }
 894
 895                 $index = substr( wfTimestampNow(), 0, 8 );
 896                 if ( !isset( $data[$index] ) ) {
 897                         $data[$index] = array();
 898                 }
 899
 900                 foreach ( self::$instance->mRequestedMessages as $message => $_ ) {
 901                         if ( !isset( $data[$index][$message] ) ) {
 902                                 $data[$index][$message] = 0;
 903                         }
 904                         $data[$index][$message]++;
 905                 }
 906
 907                 $cache->set( $cachekey, $data );
 908                 wfProfileOut( __METHOD__ );
 909         }
 910
 911         public function getMostUsedMessages() {
 912                 wfProfileIn( __METHOD__ );
 913                 $cachekey = wfMemcKey( 'message-profiling' );
 914                 $cache = wfGetCache( CACHE_DB );
 915                 $data = $cache->get( $cachekey );
 916                 if ( !$data ) {
 917                         wfProfileOut( __METHOD__ );
 918                         return array();
 919                 }
 920
 921                 $list = array();
 922
 923                 foreach( $data as $messages ) {
 924                         foreach( $messages as $message => $count ) {
 925                                 $key = $message;
 926                                 if ( !isset( $list[$key] ) ) {
 927                                         $list[$key] = 0;
 928                                 }
 929                                 $list[$key] += $count;
 930                         }
 931                 }
 932
 933                 $max = max( $list );
 934                 foreach ( $list as $message => $count ) {
 935                         if ( $count < intval( $max * self::$mAdaptiveInclusionThreshold ) ) {
 936                                 unset( $list[$message] );
 937                         }
 938                 }
 939
 940                 wfProfileOut( __METHOD__ );
 941                 return array_keys( $list );
 942         }
 943
 944 }