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