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