includes/cache/MessageCache.php

   1 <?php
   2 /**
   3  * Localisation messages cache.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Cache
  22  */
  23
  24 /**
  25  *
  26  */
  27 define( 'MSG_LOAD_TIMEOUT', 60 );
  28 define( 'MSG_LOCK_TIMEOUT', 10 );
  29 define( 'MSG_WAIT_TIMEOUT', 10 );
  30 define( 'MSG_CACHE_VERSION', 1 );
  31
  32 /**
  33  * Message cache
  34  * Performs various MediaWiki namespace-related functions
  35  * @ingroup Cache
  36  */
  37 class MessageCache {
  38         /**
  39          * Process local cache of loaded messages that are defined in
  40          * MediaWiki namespace. First array level is a language code,
  41          * second level is message key and the values are either message
  42          * content prefixed with space, or !NONEXISTENT for negative
  43          * caching.
  44          */
  45         protected $mCache;
  46
  47         // Should  mean that database cannot be used, but check
  48         protected $mDisable;
  49
  50         /// Lifetime for cache, used by object caching
  51         protected $mExpiry;
  52
  53         /**
  54          * Message cache has it's own parser which it uses to transform
  55          * messages.
  56          */
  57         protected $mParserOptions, $mParser;
  58
  59         /// Variable for tracking which variables are already loaded
  60         protected $mLoadedLanguages = array();
  61
  62         /**
  63          * Used for automatic detection of most used messages.
  64          */
  65         protected $mRequestedMessages = array();
  66
  67         /**
  68          * How long the message request counts are stored. Longer period gives
  69          * better sample, but also takes longer to adapt changes. The counts
  70          * are aggregrated per day, regardless of the value of this variable.
  71          */
  72         protected static $mAdaptiveDataAge = 604800; // Is 7*24*3600
  73
  74         /**
  75          * Filter the tail of less used messages that are requested more seldom
  76          * than this factor times the number of request of most requested message.
  77          * These messages are not loaded in the default set, but are still cached
  78          * individually on demand with the normal cache expiry time.
  79          */
  80         protected static $mAdaptiveInclusionThreshold = 0.05;
  81
  82         /**
  83          * Singleton instance
  84          *
  85          * @var MessageCache
  86          */
  87         private static $instance;
  88
  89         /**
  90          * @var bool
  91          */
  92         protected $mInParser = false;
  93
  94         /**
  95          * Get the signleton instance of this class
  96          *
  97          * @since 1.18
  98          * @return MessageCache object
  99          */
 100         public static function singleton() {
 101                 if ( is_null( self::$instance ) ) {
 102                         global $wgUseDatabaseMessages, $wgMsgCacheExpiry;
 103                         self::$instance = new self( wfGetMessageCacheStorage(), $wgUseDatabaseMessages, $wgMsgCacheExpiry );
 104                 }
 105                 return self::$instance;
 106         }
 107
 108         /**
 109          * Destroy the singleton instance
 110          *
 111          * @since 1.18
 112          */
 113         public static function destroyInstance() {
 114                 self::$instance = null;
 115         }
 116
 117         function __construct( $memCached, $useDB, $expiry ) {
 118                 if ( !$memCached ) {
 119                         $memCached = wfGetCache( CACHE_NONE );
 120                 }
 121
 122                 $this->mMemc = $memCached;
 123                 $this->mDisable = !$useDB;
 124                 $this->mExpiry = $expiry;
 125         }
 126
 127         /**
 128          * ParserOptions is lazy initialised.
 129          *
 130          * @return ParserOptions
 131          */
 132         function getParserOptions() {
 133                 if ( !$this->mParserOptions ) {
 134                         $this->mParserOptions = new ParserOptions;
 135                         $this->mParserOptions->setEditSection( false );
 136                 }
 137                 return $this->mParserOptions;
 138         }
 139
 140         /**
 141          * Try to load the cache from a local file.
 142          * Actual format of the file depends on the $wgLocalMessageCacheSerialized
 143          * setting.
 144          *
 145          * @param $hash String: the hash of contents, to check validity.
 146          * @param $code Mixed: Optional language code, see documenation of load().
 147          * @return bool on failure.
 148          */
 149         function loadFromLocal( $hash, $code ) {
 150                 global $wgCacheDirectory, $wgLocalMessageCacheSerialized;
 151
 152                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 153
 154                 # Check file existence
 155                 wfSuppressWarnings();
 156                 $file = fopen( $filename, 'r' );
 157                 wfRestoreWarnings();
 158                 if ( !$file ) {
 159                         return false; // No cache file
 160                 }
 161
 162                 if ( $wgLocalMessageCacheSerialized ) {
 163                         // Check to see if the file has the hash specified
 164                         $localHash = fread( $file, 32 );
 165                         if ( $hash === $localHash ) {
 166                                 // All good, get the rest of it
 167                                 $serialized = '';
 168                                 while ( !feof( $file ) ) {
 169                                         $serialized .= fread( $file, 100000 );
 170                                 }
 171                                 fclose( $file );
 172                                 return $this->setCache( unserialize( $serialized ), $code );
 173                         } else {
 174                                 fclose( $file );
 175                                 return false; // Wrong hash
 176                         }
 177                 } else {
 178                         $localHash = substr( fread( $file, 40 ), 8 );
 179                         fclose( $file );
 180                         if ( $hash != $localHash ) {
 181                                 return false; // Wrong hash
 182                         }
 183
 184                         # Require overwrites the member variable or just shadows it?
 185                         require( $filename );
 186                         return $this->setCache( $this->mCache, $code );
 187                 }
 188         }
 189
 190         /**
 191          * Save the cache to a local file.
 192          */
 193         function saveToLocal( $serialized, $hash, $code ) {
 194                 global $wgCacheDirectory;
 195
 196                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 197                 wfMkdirParents( $wgCacheDirectory, null, __METHOD__ ); // might fail
 198
 199                 wfSuppressWarnings();
 200                 $file = fopen( $filename, 'w' );
 201                 wfRestoreWarnings();
 202
 203                 if ( !$file ) {
 204                         wfDebug( "Unable to open local cache file for writing\n" );
 205                         return;
 206                 }
 207
 208                 fwrite( $file, $hash . $serialized );
 209                 fclose( $file );
 210                 wfSuppressWarnings();
 211                 chmod( $filename, 0666 );
 212                 wfRestoreWarnings();
 213         }
 214
 215         function saveToScript( $array, $hash, $code ) {
 216                 global $wgCacheDirectory;
 217
 218                 $filename = "$wgCacheDirectory/messages-" . wfWikiID() . "-$code";
 219                 $tempFilename = $filename . '.tmp';
 220                 wfMkdirParents( $wgCacheDirectory, null, __METHOD__ ); // might fail
 221
 222                 wfSuppressWarnings();
 223                 $file = fopen( $tempFilename, 'w' );
 224                 wfRestoreWarnings();
 225
 226                 if ( !$file ) {
 227                         wfDebug( "Unable to open local cache file for writing\n" );
 228                         return;
 229                 }
 230
 231                 fwrite( $file, "<?php\n//$hash\n\n \$this->mCache = array(" );
 232
 233                 foreach ( $array as $key => $message ) {
 234                         $key = $this->escapeForScript( $key );
 235                         $message = $this->escapeForScript( $message );
 236                         fwrite( $file, "'$key' => '$message',\n" );
 237                 }
 238
 239                 fwrite( $file, ");\n?>" );
 240                 fclose( $file);
 241                 rename( $tempFilename, $filename );
 242         }
 243
 244         function escapeForScript( $string ) {
 245                 $string = str_replace( '\\', '\\\\', $string );
 246                 $string = str_replace( '\'', '\\\'', $string );
 247                 return $string;
 248         }
 249
 250         /**
 251          * Set the cache to $cache, if it is valid. Otherwise set the cache to false.
 252          *
 253          * @return bool
 254          */
 255         function setCache( $cache, $code ) {
 256                 if ( isset( $cache['VERSION'] ) && $cache['VERSION'] == MSG_CACHE_VERSION ) {
 257                         $this->mCache[$code] = $cache;
 258                         return true;
 259                 } else {
 260                         return false;
 261                 }
 262         }
 263
 264         /**
 265          * Loads messages from caches or from database in this order:
 266          * (1) local message cache (if $wgUseLocalMessageCache is enabled)
 267          * (2) memcached
 268          * (3) from the database.
 269          *
 270          * When succesfully loading from (2) or (3), all higher level caches are
 271          * updated for the newest version.
 272          *
 273          * Nothing is loaded if member variable mDisable is true, either manually
 274          * set by calling code or if message loading fails (is this possible?).
 275          *
 276          * Returns true if cache is already populated or it was succesfully populated,
 277          * or false if populating empty cache fails. Also returns true if MessageCache
 278          * is disabled.
 279          *
 280          * @param $code String: language to which load messages
 281          * @return bool
 282          */
 283         function load( $code = false ) {
 284                 global $wgUseLocalMessageCache;
 285
 286                 if( !is_string( $code ) ) {
 287                         # This isn't really nice, so at least make a note about it and try to
 288                         # fall back
 289                         wfDebug( __METHOD__ . " called without providing a language code\n" );
 290                         $code = 'en';
 291                 }
 292
 293                 # Don't do double loading...
 294                 if ( isset( $this->mLoadedLanguages[$code] ) ) {
 295                         return true;
 296                 }
 297
 298                 # 8 lines of code just to say (once) that message cache is disabled
 299                 if ( $this->mDisable ) {
 300                         static $shownDisabled = false;
 301                         if ( !$shownDisabled ) {
 302                                 wfDebug( __METHOD__ . ": disabled\n" );
 303                                 $shownDisabled = true;
 304                         }
 305                         return true;
 306                 }
 307
 308                 # Loading code starts
 309                 wfProfileIn( __METHOD__ );
 310                 $success = false; # Keep track of success
 311                 $where = array(); # Debug info, delayed to avoid spamming debug log too much
 312                 $cacheKey = wfMemcKey( 'messages', $code ); # Key in memc for messages
 313
 314                 # (1) local cache
 315                 # Hash of the contents is stored in memcache, to detect if local cache goes
 316                 # out of date (due to update in other thread?)
 317                 if ( $wgUseLocalMessageCache ) {
 318                         wfProfileIn( __METHOD__ . '-fromlocal' );
 319
 320                         $hash = $this->mMemc->get( wfMemcKey( 'messages', $code, 'hash' ) );
 321                         if ( $hash ) {
 322                                 $success = $this->loadFromLocal( $hash, $code );
 323                                 if ( $success ) $where[] = 'got from local cache';
 324                         }
 325                         wfProfileOut( __METHOD__ . '-fromlocal' );
 326                 }
 327
 328                 # (2) memcache
 329                 # Fails if nothing in cache, or in the wrong version.
 330                 if ( !$success ) {
 331                         wfProfileIn( __METHOD__ . '-fromcache' );
 332                         $cache = $this->mMemc->get( $cacheKey );
 333                         $success = $this->setCache( $cache, $code );
 334                         if ( $success ) {
 335                                 $where[] = 'got from global cache';
 336                                 $this->saveToCaches( $cache, false, $code );
 337                         }
 338                         wfProfileOut( __METHOD__ . '-fromcache' );
 339                 }
 340
 341                 # (3)
 342                 # Nothing in caches... so we need create one and store it in caches
 343                 if ( !$success ) {
 344                         $where[] = 'cache is empty';
 345                         $where[] = 'loading from database';
 346
 347                         $this->lock( $cacheKey );
 348
 349                         # Limit the concurrency of loadFromDB to a single process
 350                         # This prevents the site from going down when the cache expires
 351                         $statusKey = wfMemcKey( 'messages', $code, 'status' );
 352                         $success = $this->mMemc->add( $statusKey, 'loading', MSG_LOAD_TIMEOUT );
 353                         if ( $success ) {
 354                                 $cache = $this->loadFromDB( $code );
 355                                 $success = $this->setCache( $cache, $code );
 356                         }
 357                         if ( $success ) {
 358                                 $success = $this->saveToCaches( $cache, true, $code );
 359                                 if ( $success ) {
 360                                         $this->mMemc->delete( $statusKey );
 361                                 } else {
 362                                         $this->mMemc->set( $statusKey, 'error', 60 * 5 );
 363                                         wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 364                                 }
 365                         }
 366                         $this->unlock($cacheKey);
 367                 }
 368
 369                 if ( !$success ) {
 370                         # Bad luck... this should not happen
 371                         $where[] = 'loading FAILED - cache is disabled';
 372                         $info = implode( ', ', $where );
 373                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 374                         $this->mDisable = true;
 375                         $this->mCache = false;
 376                 } else {
 377                         # All good, just record the success
 378                         $info = implode( ', ', $where );
 379                         wfDebug( __METHOD__ . ": Loading $code... $info\n" );
 380                         $this->mLoadedLanguages[$code] = true;
 381                 }
 382                 wfProfileOut( __METHOD__ );
 383                 return $success;
 384         }
 385
 386         /**
 387          * Loads cacheable messages from the database. Messages bigger than
 388          * $wgMaxMsgCacheEntrySize are assigned a special value, and are loaded
 389          * on-demand from the database later.
 390          *
 391          * @param $code String: language code.
 392          * @return Array: loaded messages for storing in caches.
 393          */
 394         function loadFromDB( $code ) {
 395                 wfProfileIn( __METHOD__ );
 396                 global $wgMaxMsgCacheEntrySize, $wgLanguageCode, $wgAdaptiveMessageCache;
 397                 $dbr = wfGetDB( DB_SLAVE );
 398                 $cache = array();
 399
 400                 # Common conditions
 401                 $conds = array(
 402                         'page_is_redirect' => 0,
 403                         'page_namespace' => NS_MEDIAWIKI,
 404                 );
 405
 406                 $mostused = array();
 407                 if ( $wgAdaptiveMessageCache ) {
 408                         $mostused = $this->getMostUsedMessages();
 409                         if ( $code !== $wgLanguageCode ) {
 410                                 foreach ( $mostused as $key => $value ) {
 411                                         $mostused[$key] = "$value/$code";
 412                                 }
 413                         }
 414                 }
 415
 416                 if ( count( $mostused ) ) {
 417                         $conds['page_title'] = $mostused;
 418                 } elseif ( $code !== $wgLanguageCode ) {
 419                         $conds[] = 'page_title' . $dbr->buildLike( $dbr->anyString(), "/$code" );
 420                 } else {
 421                         # Effectively disallows use of '/' character in NS_MEDIAWIKI for uses
 422                         # other than language code.
 423                         $conds[] = 'page_title NOT' . $dbr->buildLike( $dbr->anyString(), '/', $dbr->anyString() );
 424                 }
 425
 426                 # Conditions to fetch oversized pages to ignore them
 427                 $bigConds = $conds;
 428                 $bigConds[] = 'page_len > ' . intval( $wgMaxMsgCacheEntrySize );
 429
 430                 # Load titles for all oversized pages in the MediaWiki namespace
 431                 $res = $dbr->select( 'page', 'page_title', $bigConds, __METHOD__ . "($code)-big" );
 432                 foreach ( $res as $row ) {
 433                         $cache[$row->page_title] = '!TOO BIG';
 434                 }
 435
 436                 # Conditions to load the remaining pages with their contents
 437                 $smallConds = $conds;
 438                 $smallConds[] = 'page_latest=rev_id';
 439                 $smallConds[] = 'rev_text_id=old_id';
 440                 $smallConds[] = 'page_len <= ' . intval( $wgMaxMsgCacheEntrySize );
 441
 442                 $res = $dbr->select(
 443                         array( 'page', 'revision', 'text' ),
 444                         array( 'page_title', 'old_text', 'old_flags' ),
 445                         $smallConds,
 446                         __METHOD__ . "($code)-small"
 447                 );
 448
 449                 foreach ( $res as $row ) {
 450                         $text = Revision::getRevisionText( $row );
 451                         if( $text === false ) {
 452                                 // Failed to fetch data; possible ES errors?
 453                                 // Store a marker to fetch on-demand as a workaround...
 454                                 $entry = '!TOO BIG';
 455                                 wfDebugLog( 'MessageCache', __METHOD__ . ": failed to load message page text for {$row->page_title} ($code)" );
 456                         } else {
 457                                 $entry = ' ' . $text;
 458                         }
 459                         $cache[$row->page_title] = $entry;
 460                 }
 461
 462                 foreach ( $mostused as $key ) {
 463                         if ( !isset( $cache[$key] ) ) {
 464                                 $cache[$key] = '!NONEXISTENT';
 465                         }
 466                 }
 467
 468                 $cache['VERSION'] = MSG_CACHE_VERSION;
 469                 wfProfileOut( __METHOD__ );
 470                 return $cache;
 471         }
 472
 473         /**
 474          * Updates cache as necessary when message page is changed
 475          *
 476          * @param $title String: name of the page changed.
 477          * @param $text Mixed: new contents of the page.
 478          */
 479         public function replace( $title, $text ) {
 480                 global $wgMaxMsgCacheEntrySize;
 481                 wfProfileIn( __METHOD__ );
 482
 483                 if ( $this->mDisable ) {
 484                         wfProfileOut( __METHOD__ );
 485                         return;
 486                 }
 487
 488                 list( $msg, $code ) = $this->figureMessage( $title );
 489
 490                 $cacheKey = wfMemcKey( 'messages', $code );
 491                 $this->load( $code );
 492                 $this->lock( $cacheKey );
 493
 494                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 495
 496                 if ( $text === false ) {
 497                         # Article was deleted
 498                         $this->mCache[$code][$title] = '!NONEXISTENT';
 499                         $this->mMemc->delete( $titleKey );
 500                 } elseif ( strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
 501                         # Check for size
 502                         $this->mCache[$code][$title] = '!TOO BIG';
 503                         $this->mMemc->set( $titleKey, ' ' . $text, $this->mExpiry );
 504                 } else {
 505                         $this->mCache[$code][$title] = ' ' . $text;
 506                         $this->mMemc->delete( $titleKey );
 507                 }
 508
 509                 # Update caches
 510                 $this->saveToCaches( $this->mCache[$code], true, $code );
 511                 $this->unlock( $cacheKey );
 512
 513                 // Also delete cached sidebar... just in case it is affected
 514                 $codes = array( $code );
 515                 if ( $code === 'en'  ) {
 516                         // Delete all sidebars, like for example on action=purge on the
 517                         // sidebar messages
 518                         $codes = array_keys( Language::fetchLanguageNames() );
 519                 }
 520
 521                 global $wgMemc;
 522                 foreach ( $codes as $code ) {
 523                         $sidebarKey = wfMemcKey( 'sidebar', $code );
 524                         $wgMemc->delete( $sidebarKey );
 525                 }
 526
 527                 // Update the message in the message blob store
 528                 global $wgContLang;
 529                 MessageBlobStore::updateMessage( $wgContLang->lcfirst( $msg ) );
 530
 531                 wfRunHooks( 'MessageCacheReplace', array( $title, $text ) );
 532
 533                 wfProfileOut( __METHOD__ );
 534         }
 535
 536         /**
 537          * Shortcut to update caches.
 538          *
 539          * @param $cache Array: cached messages with a version.
 540          * @param $memc Bool: Wether to update or not memcache.
 541          * @param $code String: Language code.
 542          * @return bool on somekind of error.
 543          */
 544         protected function saveToCaches( $cache, $memc = true, $code = false ) {
 545                 wfProfileIn( __METHOD__ );
 546                 global $wgUseLocalMessageCache, $wgLocalMessageCacheSerialized;
 547
 548                 $cacheKey = wfMemcKey( 'messages', $code );
 549
 550                 if ( $memc ) {
 551                         $success = $this->mMemc->set( $cacheKey, $cache, $this->mExpiry );
 552                 } else {
 553                         $success = true;
 554                 }
 555
 556                 # Save to local cache
 557                 if ( $wgUseLocalMessageCache ) {
 558                         $serialized = serialize( $cache );
 559                         $hash = md5( $serialized );
 560                         $this->mMemc->set( wfMemcKey( 'messages', $code, 'hash' ), $hash, $this->mExpiry );
 561                         if ($wgLocalMessageCacheSerialized) {
 562                                 $this->saveToLocal( $serialized, $hash, $code );
 563                         } else {
 564                                 $this->saveToScript( $cache, $hash, $code );
 565                         }
 566                 }
 567
 568                 wfProfileOut( __METHOD__ );
 569                 return $success;
 570         }
 571
 572         /**
 573          * Represents a write lock on the messages key
 574          *
 575          * @param $key string
 576          *
 577          * @return Boolean: success
 578          */
 579         function lock( $key ) {
 580                 $lockKey = $key . ':lock';
 581                 for ( $i = 0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 582                         sleep( 1 );
 583                 }
 584
 585                 return $i >= MSG_WAIT_TIMEOUT;
 586         }
 587
 588         function unlock( $key ) {
 589                 $lockKey = $key . ':lock';
 590                 $this->mMemc->delete( $lockKey );
 591         }
 592
 593         /**
 594          * Get a message from either the content language or the user language.
 595          *
 596          * @param $key String: the message cache key
 597          * @param $useDB Boolean: get the message from the DB, false to use only
 598          *               the localisation
 599          * @param bool|string $langcode Code of the language to get the message for, if
 600          *                  it is a valid code create a language for that language,
 601          *                  if it is a string but not a valid code then make a basic
 602          *                  language object, if it is a false boolean then use the
 603          *                  current users language (as a fallback for the old
 604          *                  parameter functionality), or if it is a true boolean
 605          *                  then use the wikis content language (also as a
 606          *                  fallback).
 607          * @param $isFullKey Boolean: specifies whether $key is a two part key
 608          *                   "msg/lang".
 609          *
 610          * @throws MWException
 611          * @return string|bool
 612          */
 613         function get( $key, $useDB = true, $langcode = true, $isFullKey = false ) {
 614                 global $wgLanguageCode, $wgContLang;
 615
 616                 if ( is_int( $key ) ) {
 617                         // "Non-string key given" exception sometimes happens for numerical strings that become ints somewhere on their way here
 618                         $key = strval( $key );
 619                 }
 620
 621                 if ( !is_string( $key ) ) {
 622                         throw new MWException( 'Non-string key given' );
 623                 }
 624
 625                 if ( strval( $key ) === '' ) {
 626                         # Shortcut: the empty key is always missing
 627                         return false;
 628                 }
 629
 630                 $lang = wfGetLangObj( $langcode );
 631                 if ( !$lang ) {
 632                         throw new MWException( "Bad lang code $langcode given" );
 633                 }
 634
 635                 $langcode = $lang->getCode();
 636
 637                 $message = false;
 638
 639                 # Normalise title-case input (with some inlining)
 640                 $lckey = str_replace( ' ', '_', $key );
 641                 if ( ord( $key ) < 128 ) {
 642                         $lckey[0] = strtolower( $lckey[0] );
 643                         $uckey = ucfirst( $lckey );
 644                 } else {
 645                         $lckey = $wgContLang->lcfirst( $lckey );
 646                         $uckey = $wgContLang->ucfirst( $lckey );
 647                 }
 648
 649                 /**
 650                  * Record each message request, but only once per request.
 651                  * This information is not used unless $wgAdaptiveMessageCache
 652                  * is enabled.
 653                  */
 654                 $this->mRequestedMessages[$uckey] = true;
 655
 656                 # Try the MediaWiki namespace
 657                 if( !$this->mDisable && $useDB ) {
 658                         $title = $uckey;
 659                         if( !$isFullKey && ( $langcode != $wgLanguageCode ) ) {
 660                                 $title .= '/' . $langcode;
 661                         }
 662                         $message = $this->getMsgFromNamespace( $title, $langcode );
 663                 }
 664
 665                 # Try the array in the language object
 666                 if ( $message === false ) {
 667                         $message = $lang->getMessage( $lckey );
 668                         if ( is_null( $message ) ) {
 669                                 $message = false;
 670                         }
 671                 }
 672
 673                 # Try the array of another language
 674                 if( $message === false ) {
 675                         $parts = explode( '/', $lckey );
 676                         # We may get calls for things that are http-urls from sidebar
 677                         # Let's not load nonexistent languages for those
 678                         # They usually have more than one slash.
 679                         if ( count( $parts ) == 2 && $parts[1] !== '' ) {
 680                                 $message = Language::getMessageFor( $parts[0], $parts[1] );
 681                                 if ( is_null( $message ) ) {
 682                                         $message = false;
 683                                 }
 684                         }
 685                 }
 686
 687                 # Is this a custom message? Try the default language in the db...
 688                 if( ( $message === false || $message === '-' ) &&
 689                         !$this->mDisable && $useDB &&
 690                         !$isFullKey && ( $langcode != $wgLanguageCode ) ) {
 691                         $message = $this->getMsgFromNamespace( $uckey, $wgLanguageCode );
 692                 }
 693
 694                 # Final fallback
 695                 if( $message === false ) {
 696                         return false;
 697                 }
 698
 699                 # Fix whitespace
 700                 $message = strtr( $message,
 701                         array(
 702                                 # Fix for trailing whitespace, removed by textarea
 703                                 '&#32;' => ' ',
 704                                 # Fix for NBSP, converted to space by firefox
 705                                 '&nbsp;' => "\xc2\xa0",
 706                                 '&#160;' => "\xc2\xa0",
 707                         ) );
 708
 709                 return $message;
 710         }
 711
 712         /**
 713          * Get a message from the MediaWiki namespace, with caching. The key must
 714          * first be converted to two-part lang/msg form if necessary.
 715          *
 716          * @param $title String: Message cache key with initial uppercase letter.
 717          * @param $code String: code denoting the language to try.
 718          *
 719          * @return string|bool False on failure
 720          */
 721         function getMsgFromNamespace( $title, $code ) {
 722                 global $wgAdaptiveMessageCache;
 723
 724                 $this->load( $code );
 725                 if ( isset( $this->mCache[$code][$title] ) ) {
 726                         $entry = $this->mCache[$code][$title];
 727                         if ( substr( $entry, 0, 1 ) === ' ' ) {
 728                                 return substr( $entry, 1 );
 729                         } elseif ( $entry === '!NONEXISTENT' ) {
 730                                 return false;
 731                         } elseif( $entry === '!TOO BIG' ) {
 732                                 // Fall through and try invididual message cache below
 733                         }
 734                 } else {
 735                         // XXX: This is not cached in process cache, should it?
 736                         $message = false;
 737                         wfRunHooks( 'MessagesPreLoad', array( $title, &$message ) );
 738                         if ( $message !== false ) {
 739                                 return $message;
 740                         }
 741
 742                         /**
 743                          * If message cache is in normal mode, it is guaranteed
 744                          * (except bugs) that there is always entry (or placeholder)
 745                          * in the cache if message exists. Thus we can do minor
 746                          * performance improvement and return false early.
 747                          */
 748                         if ( !$wgAdaptiveMessageCache ) {
 749                                 return false;
 750                         }
 751                 }
 752
 753                 # Try the individual message cache
 754                 $titleKey = wfMemcKey( 'messages', 'individual', $title );
 755                 $entry = $this->mMemc->get( $titleKey );
 756                 if ( $entry ) {
 757                         if ( substr( $entry, 0, 1 ) === ' ' ) {
 758                                 $this->mCache[$code][$title] = $entry;
 759                                 return substr( $entry, 1 );
 760                         } elseif ( $entry === '!NONEXISTENT' ) {
 761                                 $this->mCache[$code][$title] = '!NONEXISTENT';
 762                                 return false;
 763                         } else {
 764                                 # Corrupt/obsolete entry, delete it
 765                                 $this->mMemc->delete( $titleKey );
 766                         }
 767                 }
 768
 769                 # Try loading it from the database
 770                 $revision = Revision::newFromTitle(
 771                         Title::makeTitle( NS_MEDIAWIKI, $title ), false, Revision::READ_LATEST
 772                 );
 773                 if ( $revision ) {
 774                         $content = $revision->getContent();
 775                         if ( !$content ) {
 776                                 // A possibly temporary loading failure.
 777                                 wfDebugLog( 'MessageCache', __METHOD__ . ": failed to load message page text for {$title} ($code)" );
 778                                 $message = null; // no negative caching
 779                         } else {
 780                                 // XXX: Is this the right way to turn a Content object into a message?
 781                                 // NOTE: $content is typically either WikitextContent, JavaScriptContent or CssContent.
 782                                 //       MessageContent is *not* used for storing messages, it's only used for wrapping them when needed.
 783                                 $message = $content->getWikitextForTransclusion();
 784
 785                                 if ( $message === false || $message === null ) {
 786                                         wfDebugLog( 'MessageCache', __METHOD__ . ": message content doesn't provide wikitext "
 787                                                                 . "(content model: " . $content->getContentHandler() . ")" );
 788
 789                                         $message = false; // negative caching
 790                                 } else {
 791                                         $this->mCache[$code][$title] = ' ' . $message;
 792                                         $this->mMemc->set( $titleKey, ' ' . $message, $this->mExpiry );
 793                                 }
 794                         }
 795                 } else {
 796                         $message = false; // negative caching
 797                 }
 798
 799                 if ( $message === false ) { // negative caching
 800                         $this->mCache[$code][$title] = '!NONEXISTENT';
 801                         $this->mMemc->set( $titleKey, '!NONEXISTENT', $this->mExpiry );
 802                 }
 803
 804                 return $message;
 805         }
 806
 807         /**
 808          * @param $message string
 809          * @param $interface bool
 810          * @param $language
 811          * @param $title Title
 812          * @return string
 813          */
 814         function transform( $message, $interface = false, $language = null, $title = null ) {
 815                 // Avoid creating parser if nothing to transform
 816                 if( strpos( $message, '{{' ) === false ) {
 817                         return $message;
 818                 }
 819
 820                 if ( $this->mInParser ) {
 821                         return $message;
 822                 }
 823
 824                 $parser = $this->getParser();
 825                 if ( $parser ) {
 826                         $popts = $this->getParserOptions();
 827                         $popts->setInterfaceMessage( $interface );
 828                         $popts->setTargetLanguage( $language );
 829
 830                         $userlang = $popts->setUserLang( $language );
 831                         $this->mInParser = true;
 832                         $message = $parser->transformMsg( $message, $popts, $title );
 833                         $this->mInParser = false;
 834                         $popts->setUserLang( $userlang );
 835                 }
 836                 return $message;
 837         }
 838
 839         /**
 840          * @return Parser
 841          */
 842         function getParser() {
 843                 global $wgParser, $wgParserConf;
 844                 if ( !$this->mParser && isset( $wgParser ) ) {
 845                         # Do some initialisation so that we don't have to do it twice
 846                         $wgParser->firstCallInit();
 847                         # Clone it and store it
 848                         $class = $wgParserConf['class'];
 849                         if ( $class == 'Parser_DiffTest' ) {
 850                                 # Uncloneable
 851                                 $this->mParser = new $class( $wgParserConf );
 852                         } else {
 853                                 $this->mParser = clone $wgParser;
 854                         }
 855                 }
 856                 return $this->mParser;
 857         }
 858
 859         /**
 860          * @param $text string
 861          * @param $title Title
 862          * @param $linestart bool
 863          * @param $interface bool
 864          * @param $language
 865          * @return ParserOutput
 866          */
 867         public function parse( $text, $title = null, $linestart = true, $interface = false, $language = null  ) {
 868                 if ( $this->mInParser ) {
 869                         return htmlspecialchars( $text );
 870                 }
 871
 872                 $parser = $this->getParser();
 873                 $popts = $this->getParserOptions();
 874                 $popts->setInterfaceMessage( $interface );
 875                 $popts->setTargetLanguage( $language );
 876
 877                 wfProfileIn( __METHOD__ );
 878                 if ( !$title || !$title instanceof Title ) {
 879                         global $wgTitle;
 880                         $title = $wgTitle;
 881                 }
 882                 // Sometimes $wgTitle isn't set either...
 883                 if ( !$title ) {
 884                         # It's not uncommon having a null $wgTitle in scripts. See r80898
 885                         # Create a ghost title in such case
 886                         $title = Title::newFromText( 'Dwimmerlaik' );
 887                 }
 888
 889                 $this->mInParser = true;
 890                 $res = $parser->parse( $text, $title, $popts, $linestart );
 891                 $this->mInParser = false;
 892
 893                 wfProfileOut( __METHOD__ );
 894                 return $res;
 895         }
 896
 897         function disable() {
 898                 $this->mDisable = true;
 899         }
 900
 901         function enable() {
 902                 $this->mDisable = false;
 903         }
 904
 905         /**
 906          * Clear all stored messages. Mainly used after a mass rebuild.
 907          */
 908         function clear() {
 909                 $langs = Language::fetchLanguageNames( null, 'mw' );
 910                 foreach ( array_keys($langs) as $code ) {
 911                         # Global cache
 912                         $this->mMemc->delete( wfMemcKey( 'messages', $code ) );
 913                         # Invalidate all local caches
 914                         $this->mMemc->delete( wfMemcKey( 'messages', $code, 'hash' ) );
 915                 }
 916                 $this->mLoadedLanguages = array();
 917         }
 918
 919         /**
 920          * @param $key
 921          * @return array
 922          */
 923         public function figureMessage( $key ) {
 924                 global $wgLanguageCode;
 925                 $pieces = explode( '/', $key );
 926                 if( count( $pieces ) < 2 ) {
 927                         return array( $key, $wgLanguageCode );
 928                 }
 929
 930                 $lang = array_pop( $pieces );
 931                 if( !Language::fetchLanguageName( $lang, null, 'mw' ) ) {
 932                         return array( $key, $wgLanguageCode );
 933                 }
 934
 935                 $message = implode( '/', $pieces );
 936                 return array( $message, $lang );
 937         }
 938
 939         public static function logMessages() {
 940                 wfProfileIn( __METHOD__ );
 941                 global $wgAdaptiveMessageCache;
 942                 if ( !$wgAdaptiveMessageCache || !self::$instance instanceof MessageCache ) {
 943                         wfProfileOut( __METHOD__ );
 944                         return;
 945                 }
 946
 947                 $cachekey = wfMemckey( 'message-profiling' );
 948                 $cache = wfGetCache( CACHE_DB );
 949                 $data = $cache->get( $cachekey );
 950
 951                 if ( !$data ) {
 952                         $data = array();
 953                 }
 954
 955                 $age = self::$mAdaptiveDataAge;
 956                 $filterDate = substr( wfTimestamp( TS_MW, time() - $age ), 0, 8 );
 957                 foreach ( array_keys( $data ) as $key ) {
 958                         if ( $key < $filterDate ) {
 959                                 unset( $data[$key] );
 960                         }
 961                 }
 962
 963                 $index = substr( wfTimestampNow(), 0, 8 );
 964                 if ( !isset( $data[$index] ) ) {
 965                         $data[$index] = array();
 966                 }
 967
 968                 foreach ( self::$instance->mRequestedMessages as $message => $_ ) {
 969                         if ( !isset( $data[$index][$message] ) ) {
 970                                 $data[$index][$message] = 0;
 971                         }
 972                         $data[$index][$message]++;
 973                 }
 974
 975                 $cache->set( $cachekey, $data );
 976                 wfProfileOut( __METHOD__ );
 977         }
 978
 979         /**
 980          * @return array
 981          */
 982         public function getMostUsedMessages() {
 983                 wfProfileIn( __METHOD__ );
 984                 $cachekey = wfMemcKey( 'message-profiling' );
 985                 $cache = wfGetCache( CACHE_DB );
 986                 $data = $cache->get( $cachekey );
 987                 if ( !$data ) {
 988                         wfProfileOut( __METHOD__ );
 989                         return array();
 990                 }
 991
 992                 $list = array();
 993
 994                 foreach( $data as $messages ) {
 995                         foreach( $messages as $message => $count ) {
 996                                 $key = $message;
 997                                 if ( !isset( $list[$key] ) ) {
 998                                         $list[$key] = 0;
 999                                 }
1000                                 $list[$key] += $count;
1001                         }
1002                 }
1003
1004                 $max = max( $list );
1005                 foreach ( $list as $message => $count ) {
1006                         if ( $count < intval( $max * self::$mAdaptiveInclusionThreshold ) ) {
1007                                 unset( $list[$message] );
1008                         }
1009                 }
1010
1011                 wfProfileOut( __METHOD__ );
1012                 return array_keys( $list );
1013         }
1014
1015         /**
1016          * Get all message keys stored in the message cache for a given language.
1017          * If $code is the content language code, this will return all message keys
1018          * for which MediaWiki:msgkey exists. If $code is another language code, this
1019          * will ONLY return message keys for which MediaWiki:msgkey/$code exists.
1020          * @param $code string
1021          * @return array of message keys (strings)
1022          */
1023         public function getAllMessageKeys( $code ) {
1024                 global $wgContLang;
1025                 $this->load( $code );
1026                 if ( !isset( $this->mCache[$code] ) ) {
1027                         // Apparently load() failed
1028                         return null;
1029                 }
1030                 $cache = $this->mCache[$code]; // Copy the cache
1031                 unset( $cache['VERSION'] ); // Remove the VERSION key
1032                 $cache = array_diff( $cache, array( '!NONEXISTENT' ) ); // Remove any !NONEXISTENT keys
1033                 // Keys may appear with a capital first letter. lcfirst them.
1034                 return array_map( array( $wgContLang, 'lcfirst' ), array_keys( $cache ) );
1035         }
1036 }