includes/MessageCache.php

   1 <?php
   2 /**
   3  *
   4  * @package MediaWiki
   5  * @subpackage Cache
   6  */
   7
   8 /** */
   9 require_once( 'Revision.php' );
  10
  11 /**
  12  *
  13  */
  14 define( 'MSG_LOAD_TIMEOUT', 60);
  15 define( 'MSG_LOCK_TIMEOUT', 10);
  16 define( 'MSG_WAIT_TIMEOUT', 10);
  17
  18 /**
  19  * Message cache
  20  * Performs various useful MediaWiki namespace-related functions
  21  *
  22  * @package MediaWiki
  23  */
  24 class MessageCache {
  25         var $mCache, $mUseCache, $mDisable, $mExpiry;
  26         var $mMemcKey, $mKeys, $mParserOptions, $mParser;
  27         var $mExtensionMessages = array();
  28         var $mInitialised = false;
  29         var $mDeferred = true;
  30
  31         function initialise( &$memCached, $useDB, $expiry, $memcPrefix) {
  32                 $fname = 'MessageCache::initialise';
  33                 wfProfileIn( $fname );
  34
  35                 $this->mUseCache = !is_null( $memCached );
  36                 $this->mMemc = &$memCached;
  37                 $this->mDisable = !$useDB;
  38                 $this->mExpiry = $expiry;
  39                 $this->mDisableTransform = false;
  40                 $this->mMemcKey = $memcPrefix.':messages';
  41                 $this->mKeys = false; # initialised on demand
  42                 $this->mInitialised = true;
  43
  44                 wfProfileIn( $fname.'-parseropt' );
  45                 $this->mParserOptions = ParserOptions::newFromUser( $u=NULL );
  46                 wfProfileOut( $fname.'-parseropt' );
  47                 wfProfileIn( $fname.'-parser' );
  48                 $this->mParser = new Parser;
  49                 wfProfileOut( $fname.'-parser' );
  50
  51                 # When we first get asked for a message,
  52                 # then we'll fill up the cache. If we
  53                 # can return a cache hit, this saves
  54                 # some extra milliseconds
  55                 $this->mDeferred = true;
  56
  57                 wfProfileOut( $fname );
  58         }
  59
  60         /**
  61          * Try to load the cache from a local file
  62          */
  63         function loadFromLocal( $hash ) {
  64                 global $wgLocalMessageCache, $wgDBname;
  65
  66                 $this->mCache = false;
  67                 if ( $wgLocalMessageCache === false ) {
  68                         return;
  69                 }
  70
  71                 $filename = "$wgLocalMessageCache/messages-$wgDBname";
  72
  73                 $file = fopen( $filename, 'r' );
  74                 if ( !$file ) {
  75                         return;
  76                 }
  77
  78                 // Check to see if the file has the hash specified
  79                 $localHash = fread( $file, 32 );
  80                 if ( $hash == $localHash ) {
  81                         // All good, get the rest of it
  82                         $serialized = fread( $file, 1000000 );
  83                         $this->mCache = unserialize( $serialized );
  84                 }
  85                 fclose( $file );
  86         }
  87
  88         /**
  89          * Save the cache to a local file
  90          */
  91         function saveToLocal( $serialized, $hash ) {
  92                 global $wgLocalMessageCache, $wgDBname;
  93
  94                 if ( $wgLocalMessageCache === false ) {
  95                         return;
  96                 }
  97
  98                 $filename = "$wgLocalMessageCache/messages-$wgDBname";
  99                 wfMkdirParents( $wgLocalMessageCache, 0777 );
 100
 101                 $file = fopen( $filename, 'w' );
 102                 if ( !$file ) {
 103                         wfDebug( "Unable to open local cache file for writing\n" );
 104                         return;
 105                 }
 106
 107                 fwrite( $file, $hash . $serialized );
 108                 fclose( $file );
 109         }
 110
 111
 112         /**
 113          * Loads messages either from memcached or the database, if not disabled
 114          * On error, quietly switches to a fallback mode
 115          * Returns false for a reportable error, true otherwise
 116          */
 117         function load() {
 118                 global $wgLocalMessageCache;
 119
 120                 if ( $this->mDisable ) {
 121                         static $shownDisabled = false;
 122                         if ( !$shownDisabled ) {
 123                                 wfDebug( "MessageCache::load(): disabled\n" );
 124                                 $shownDisabled = true;
 125                         }
 126                         return true;
 127                 }
 128                 $fname = 'MessageCache::load';
 129                 wfProfileIn( $fname );
 130                 $success = true;
 131
 132                 if ( $this->mUseCache ) {
 133                         $this->mCache = false;
 134
 135                         # Try local cache
 136                         wfProfileIn( $fname.'-fromlocal' );
 137                         $hash = $this->mMemc->get( "{$this->mMemcKey}-hash" );
 138                         if ( $hash ) {
 139                                 $this->loadFromLocal( $hash );
 140                         }
 141                         wfProfileOut( $fname.'-fromlocal' );
 142
 143                         # Try memcached
 144                         if ( !$this->mCache ) {
 145                                 wfProfileIn( $fname.'-fromcache' );
 146                                 $this->mCache = $this->mMemc->get( $this->mMemcKey );
 147
 148                                 # Save to local cache
 149                                 if ( $wgLocalMessageCache !== false ) {
 150                                         $serialized = serialize( $this->mCache );
 151                                         if ( !$hash ) {
 152                                                 $hash = md5( $serialized );
 153                                                 $this->mMemc->set( "{$this->mMemcKey}-hash", $hash, $this->mExpiry );
 154                                         }
 155                                         $this->saveToLocal( $serialized, $hash );
 156                                 }
 157                                 wfProfileOut( $fname.'-fromcache' );
 158                         }
 159
 160
 161                         # If there's nothing in memcached, load all the messages from the database
 162                         if ( !$this->mCache ) {
 163                                 wfDebug( "MessageCache::load(): loading all messages\n" );
 164                                 $this->lock();
 165                                 # Other threads don't need to load the messages if another thread is doing it.
 166                                 $success = $this->mMemc->add( $this->mMemcKey.'-status', "loading", MSG_LOAD_TIMEOUT );
 167                                 if ( $success ) {
 168                                         wfProfileIn( $fname.'-load' );
 169                                         $this->loadFromDB();
 170                                         wfProfileOut( $fname.'-load' );
 171
 172                                         # Save in memcached
 173                                         # Keep trying if it fails, this is kind of important
 174                                         wfProfileIn( $fname.'-save' );
 175                                         for ($i=0; $i<20 &&
 176                                                    !$this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 177                                              $i++ ) {
 178                                                 usleep(mt_rand(500000,1500000));
 179                                         }
 180
 181                                         # Save to local cache
 182                                         if ( $wgLocalMessageCache !== false ) {
 183                                                 $serialized = serialize( $this->mCache );
 184                                                 $hash = md5( $serialized );
 185                                                 $this->mMemc->set( "{$this->mMemcKey}-hash", $hash, $this->mExpiry );
 186                                                 $this->saveToLocal( $serialized, $hash );
 187                                         }
 188
 189                                         wfProfileOut( $fname.'-save' );
 190                                         if ( $i == 20 ) {
 191                                                 $this->mMemc->set( $this->mMemcKey.'-status', 'error', 60*5 );
 192                                                 wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 193                                         }
 194                                 }
 195                                 $this->unlock();
 196                         }
 197
 198                         if ( !is_array( $this->mCache ) ) {
 199                                 wfDebug( "MessageCache::load(): individual message mode\n" );
 200                                 # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
 201                                 # Causing too much DB load, disabling -- TS
 202                                 $this->mDisable = true;
 203                                 /*
 204                                 if ( $this->mCache == "loading" ) {
 205                                         $this->mUseCache = false;
 206                                 } elseif ( $this->mCache == "error" ) {
 207                                         $this->mUseCache = false;
 208                                         $success = false;
 209                                 } else {
 210                                         $this->mDisable = true;
 211                                         $success = false;
 212                                 }*/
 213                                 $this->mCache = false;
 214                         }
 215                 }
 216                 wfProfileOut( $fname );
 217                 $this->mDeferred = false;
 218                 return $success;
 219         }
 220
 221         /**
 222          * Loads all or main part of cacheable messages from the database
 223          */
 224         function loadFromDB() {
 225                 global $wgAllMessagesEn, $wgLang;
 226
 227                 $fname = 'MessageCache::loadFromDB';
 228                 $dbr =& wfGetDB( DB_SLAVE );
 229                 if ( !$dbr ) {
 230                         wfDebugDieBacktrace( 'Invalid database object' );
 231                 }
 232                 $conditions = array( 'page_is_redirect' => 0,
 233                                         'page_namespace' => NS_MEDIAWIKI);
 234                 $res = $dbr->select( array( 'page', 'revision', 'text' ),
 235                         array( 'page_title', 'old_text', 'old_flags' ),
 236                         'page_is_redirect=0 AND page_namespace='.NS_MEDIAWIKI.' AND page_latest=rev_id AND rev_text_id=old_id',
 237                         $fname
 238                 );
 239
 240                 $this->mCache = array();
 241                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 242                         $this->mCache[$row->page_title] = Revision::getRevisionText( $row );
 243                 }
 244
 245                 # Negative caching
 246                 # Go through the language array and the extension array and make a note of
 247                 # any keys missing from the cache
 248                 foreach ( $wgAllMessagesEn as $key => $value ) {
 249                         $uckey = $wgLang->ucfirst( $key );
 250                         if ( !array_key_exists( $uckey, $this->mCache ) ) {
 251                                 $this->mCache[$uckey] = false;
 252                         }
 253                 }
 254                 foreach ( $this->mExtensionMessages as $key => $value ) {
 255                         $uckey = $wgLang->ucfirst( $key );
 256                         if ( !array_key_exists( $uckey, $this->mCache ) ) {
 257                                 $this->mCache[$uckey] = false;
 258                         }
 259                 }
 260
 261                 $dbr->freeResult( $res );
 262         }
 263
 264         /**
 265          * Not really needed anymore
 266          */
 267         function getKeys() {
 268                 global $wgAllMessagesEn, $wgContLang;
 269                 if ( !$this->mKeys ) {
 270                         $this->mKeys = array();
 271                         foreach ( $wgAllMessagesEn as $key => $value ) {
 272                                 $title = $wgContLang->ucfirst( $key );
 273                                 array_push( $this->mKeys, $title );
 274                         }
 275                 }
 276                 return $this->mKeys;
 277         }
 278
 279         /**
 280          * @deprecated
 281          */
 282         function isCacheable( $key ) {
 283                 return true;
 284         }
 285
 286         function replace( $title, $text ) {
 287                 global $wgLocalMessageCache;
 288
 289                 $this->lock();
 290                 $this->load();
 291                 if ( is_array( $this->mCache ) ) {
 292                         $this->mCache[$title] = $text;
 293                         $this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 294
 295                         # Save to local cache
 296                         if ( $wgLocalMessageCache !== false ) {
 297                                 $serialized = serialize( $this->mCache );
 298                                 $hash = md5( $serialized );
 299                                 $this->mMemc->set( "{$this->mMemcKey}-hash", $hash, $this->mExpiry );
 300                                 $this->saveToLocal( $serialized, $hash );
 301                         }
 302
 303
 304                 }
 305                 $this->unlock();
 306         }
 307
 308         /**
 309          * Returns success
 310          * Represents a write lock on the messages key
 311          */
 312         function lock() {
 313                 if ( !$this->mUseCache ) {
 314                         return true;
 315                 }
 316
 317                 $lockKey = $this->mMemcKey . 'lock';
 318                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 319                         sleep(1);
 320                 }
 321
 322                 return $i >= MSG_WAIT_TIMEOUT;
 323         }
 324
 325         function unlock() {
 326                 if ( !$this->mUseCache ) {
 327                         return;
 328                 }
 329
 330                 $lockKey = $this->mMemcKey . 'lock';
 331                 $this->mMemc->delete( $lockKey );
 332         }
 333
 334         function get( $key, $useDB, $forcontent=true, $isfullkey = false ) {
 335                 global $wgContLanguageCode;
 336                 if( $forcontent ) {
 337                         global $wgContLang;
 338                         $lang =& $wgContLang;
 339                         $langcode = $wgContLanguageCode;
 340                 } else {
 341                         global $wgLang, $wgLanguageCode;
 342                         $lang =& $wgLang;
 343                         $langcode = $wgLanguageCode;
 344                 }
 345                 # If uninitialised, someone is trying to call this halfway through Setup.php
 346                 if( !$this->mInitialised ) {
 347                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 348                 }
 349                 # If cache initialization was deferred, start it now.
 350                 if( $this->mDeferred && !$this->mDisable && $useDB ) {
 351                         $this->load();
 352                 }
 353
 354                 $message = false;
 355                 if( !$this->mDisable && $useDB ) {
 356                         $title = $lang->ucfirst( $key );
 357                         if(!$isfullkey && ($langcode != $wgContLanguageCode) ) {
 358                                 $title .= '/' . $langcode;
 359                         }
 360                         $message = $this->getFromCache( $title );
 361                 }
 362                 # Try the extension array
 363                 if( $message === false && array_key_exists( $key, $this->mExtensionMessages ) ) {
 364                         $message = $this->mExtensionMessages[$key];
 365                 }
 366
 367                 # Try the array in the language object
 368                 if( $message === false ) {
 369                         wfSuppressWarnings();
 370                         $message = $lang->getMessage( $key );
 371                         wfRestoreWarnings();
 372                         if ( is_null( $message ) ) {
 373                                 $message = false;
 374                         }
 375                 }
 376
 377                 # Try the English array
 378                 if( $message === false && $langcode != 'en' ) {
 379                         wfSuppressWarnings();
 380                         $message = Language::getMessage( $key );
 381                         wfRestoreWarnings();
 382                         if ( is_null( $message ) ) {
 383                                 $message = false;
 384                         }
 385                 }
 386
 387                 # Is this a custom message? Try the default language in the db...
 388                 if( $message === false &&
 389                         !$this->mDisable && $useDB &&
 390                         !$isfullkey && ($langcode != $wgContLanguageCode) ) {
 391                         $message = $this->getFromCache( $lang->ucfirst( $key ) );
 392                 }
 393
 394                 # Final fallback
 395                 if( $message === false ) {
 396                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 397                 }
 398
 399                 # Replace brace tags
 400                 $message = $this->transform( $message );
 401                 return $message;
 402         }
 403
 404         function getFromCache( $title ) {
 405                 $message = false;
 406
 407                 # Try the cache
 408                 if( $this->mUseCache && is_array( $this->mCache ) && array_key_exists( $title, $this->mCache ) ) {
 409                         return $this->mCache[$title];
 410                 }
 411
 412                 # Try individual message cache
 413                 if ( $this->mUseCache ) {
 414                         $message = $this->mMemc->get( $this->mMemcKey . ':' . $title );
 415                         if ( $message == '###NONEXISTENT###' ) {
 416                                 return false;
 417                         } elseif( !is_null( $message ) ) {
 418                                 $this->mCache[$title] = $message;
 419                                 return $message;
 420                         } else {
 421                                 $message = false;
 422                         }
 423                 }
 424
 425                 # If it wasn't in the cache, load each message from the DB individually
 426                 $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 427                 if( $revision ) {
 428                         $message = $revision->getText();
 429                         if ($this->mUseCache) {
 430                                 $this->mCache[$title]=$message;
 431                                 /* individual messages may be often
 432                                    recached until proper purge code exists
 433                                 */
 434                                 $this->mMemc->set( $this->mMemcKey . ':' . $title, $message, 300 );
 435                         }
 436                 } else {
 437                         # Negative caching
 438                         # Use some special text instead of false, because false gets converted to '' somewhere
 439                         $this->mMemc->set( $this->mMemcKey . ':' . $title, '###NONEXISTENT###', $this->mExpiry );
 440                 }
 441
 442                 return $message;
 443         }
 444
 445         function transform( $message ) {
 446                 if( !$this->mDisableTransform ) {
 447                         if( strpos( $message, '{{' ) !== false ) {
 448                                 $message = $this->mParser->transformMsg( $message, $this->mParserOptions );
 449                         }
 450                 }
 451                 return $message;
 452         }
 453
 454         function disable() { $this->mDisable = true; }
 455         function enable() { $this->mDisable = false; }
 456         function disableTransform() { $this->mDisableTransform = true; }
 457         function enableTransform() { $this->mDisableTransform = false; }
 458         function setTransform( $x ) { $this->mDisableTransform = $x; }
 459         function getTransform() { return $this->mDisableTransform; }
 460
 461         /**
 462          * Add a message to the cache
 463          *
 464          * @param mixed $key
 465          * @param mixed $value
 466          */
 467         function addMessage( $key, $value ) {
 468                 $this->mExtensionMessages[$key] = $value;
 469         }
 470
 471         /**
 472          * Add an associative array of message to the cache
 473          *
 474          * @param array $messages An associative array of key => values to be added
 475          */
 476         function addMessages( $messages ) {
 477                 foreach ( $messages as $key => $value ) {
 478                         $this->addMessage( $key, $value );
 479                 }
 480         }
 481
 482         /**
 483          * Clear all stored messages. Mainly used after a mass rebuild.
 484          */
 485         function clear() {
 486                 if( $this->mUseCache ) {
 487                         $this->mMemc->delete( $this->mMemcKey );
 488                 }
 489         }
 490 }
 491 ?>