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