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                 $fname = 'MessageCache::loadFromDB';
 141                 $dbr =& wfGetDB( DB_SLAVE );
 142                 $conditions = array( 'page_is_redirect' => 0,
 143                                         'page_namespace' => NS_MEDIAWIKI);
 144                 $res = $dbr->select( array( 'page', 'revision', 'text' ),
 145                         array( 'page_title', 'old_text', 'old_flags' ),
 146                         'page_is_redirect=0 AND page_namespace='.NS_MEDIAWIKI.' AND page_latest=rev_id AND rev_text_id=old_id',
 147                         $fname
 148                 );
 149
 150                 $this->mCache = array();
 151                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 152                         $this->mCache[$row->page_title] = Revision::getRevisionText( $row );
 153                 }
 154
 155                 $dbr->freeResult( $res );
 156                 /*
 157                 # FIXME: This is too slow currently.
 158                 # We need to bulk-fetch revisions, but in a portable way...
 159                 $resultSet = Revision::fetchFromConds( $dbr, array(
 160                         'page_namespace'   => NS_MEDIAWIKI,
 161                         'page_is_redirect' => 0,
 162                         'page_id=rev_page' ) );
 163                 while( $row = $resultSet->fetchObject() ) {
 164                         $revision = new Revision( $row );
 165                         $title = $revision->getTitle();
 166                         $this->mCache[$title->getDBkey()] = $revision->getText();
 167                 }
 168                 $resultSet->free();
 169                 */
 170         }
 171
 172         /**
 173          * Not really needed anymore
 174          */
 175         function getKeys() {
 176                 global $wgAllMessagesEn, $wgContLang;
 177                 if ( !$this->mKeys ) {
 178                         $this->mKeys = array();
 179                         foreach ( $wgAllMessagesEn as $key => $value ) {
 180                                 $title = $wgContLang->ucfirst( $key );
 181                                 array_push( $this->mKeys, $title );
 182                         }
 183                 }
 184                 return $this->mKeys;
 185         }
 186
 187         /**
 188          * @deprecated
 189          */
 190         function isCacheable( $key ) {
 191                 return true;
 192         }
 193
 194         function replace( $title, $text ) {
 195                 $this->lock();
 196                 $this->load();
 197                 if ( is_array( $this->mCache ) ) {
 198                         $this->mCache[$title] = $text;
 199                         $this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 200                 }
 201                 $this->unlock();
 202         }
 203
 204         /**
 205          * Returns success
 206          * Represents a write lock on the messages key
 207          */
 208         function lock() {
 209                 if ( !$this->mUseCache ) {
 210                         return true;
 211                 }
 212
 213                 $lockKey = $this->mMemcKey . 'lock';
 214                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 215                         sleep(1);
 216                 }
 217
 218                 return $i >= MSG_WAIT_TIMEOUT;
 219         }
 220
 221         function unlock() {
 222                 if ( !$this->mUseCache ) {
 223                         return;
 224                 }
 225
 226                 $lockKey = $this->mMemcKey . 'lock';
 227                 $this->mMemc->delete( $lockKey );
 228         }
 229
 230         function get( $key, $useDB, $forcontent=true, $isfullkey = false ) {
 231                 global $wgContLanguageCode;
 232                 if( $forcontent ) {
 233                         global $wgContLang;
 234                         $lang =& $wgContLang;
 235                         $langcode = $wgContLanguageCode;
 236                 } else {
 237                         global $wgLang, $wgLanguageCode;
 238                         $lang =& $wgLang;
 239                         $langcode = $wgLanguageCode;
 240                 }
 241                 # If uninitialised, someone is trying to call this halfway through Setup.php
 242                 if( !$this->mInitialised ) {
 243                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 244                 }
 245                 # If cache initialization was deferred, start it now.
 246                 if( $this->mDeferred ) {
 247                         $this->load();
 248                 }
 249
 250                 $message = false;
 251                 if( !$this->mDisable && $useDB ) {
 252                         $title = $lang->ucfirst( $key );
 253                         if(!$isfullkey && ($langcode != $wgContLanguageCode) ) {
 254                                 $title .= '/' . $langcode;
 255                         }
 256                         $message = $this->getFromCache( $title );
 257                 }
 258                 # Try the extension array
 259                 if( !$message ) {
 260                         $message = @$this->mExtensionMessages[$key];
 261                 }
 262
 263                 # Try the array in the language object
 264                 if( !$message ) {
 265                         wfSuppressWarnings();
 266                         $message = $lang->getMessage( $key );
 267                         wfRestoreWarnings();
 268                 }
 269
 270                 # Try the English array
 271                 if( !$message && $langcode != 'en' ) {
 272                         wfSuppressWarnings();
 273                         $message = Language::getMessage( $key );
 274                         wfRestoreWarnings();
 275                 }
 276
 277                 # Is this a custom message? Try the default language in the db...
 278                 if( !$message &&
 279                         !$this->mDisable && $useDB &&
 280                         !$isfullkey && ($langcode != $wgContLanguageCode) ) {
 281                         $message = $this->getFromCache( $lang->ucfirst( $key ) );
 282                 }
 283
 284                 # Final fallback
 285                 if( !$message ) {
 286                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 287                 }
 288
 289                 # Replace brace tags
 290                 $message = $this->transform( $message );
 291                 return $message;
 292         }
 293
 294         function getFromCache( $title ) {
 295                 $message = false;
 296
 297                 # Try the cache
 298                 if( $this->mUseCache && is_array( $this->mCache ) && array_key_exists( $title, $this->mCache ) ) {
 299                         $message = $this->mCache[$title];
 300                 }
 301
 302                 if ( !$message && $this->mUseCache ) {
 303                         $message = $this->mMemc->get( $this->mMemcKey . ':' . $title );
 304                         if( $message ) {
 305                                 $this->mCache[$title] = $message;
 306                         }
 307                 }
 308
 309                 # Call message Hooks, in case they are defined
 310                 wfRunHooks('MessagesPreLoad',array($title,&$message));
 311
 312                 # If it wasn't in the cache, load each message from the DB individually
 313                 if ( !$message ) {
 314                         $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 315                         if( $revision ) {
 316                                 $message = $revision->getText();
 317                                 if ($this->mUseCache) {
 318                                         $this->mCache[$title]=$message;
 319                                         /* individual messages may be often
 320                                            recached until proper purge code exists
 321                                         */
 322                                         $this->mMemc->set( $this->mMemcKey . ':' . $title, $message, 300 );
 323                                 }
 324                         }
 325                 }
 326
 327                 return $message;
 328         }
 329
 330         function transform( $message ) {
 331                 if( !$this->mDisableTransform ) {
 332                         if( strpos( $message, '{{' ) !== false ) {
 333                                 $message = $this->mParser->transformMsg( $message, $this->mParserOptions );
 334                         }
 335                 }
 336                 return $message;
 337         }
 338
 339         function disable() { $this->mDisable = true; }
 340         function enable() { $this->mDisable = false; }
 341         function disableTransform() { $this->mDisableTransform = true; }
 342         function enableTransform() { $this->mDisableTransform = false; }
 343
 344         /**
 345          * Add a message to the cache
 346          *
 347          * @param mixed $key
 348          * @param mixed $value
 349          */
 350         function addMessage( $key, $value ) {
 351                 $this->mExtensionMessages[$key] = $value;
 352         }
 353
 354         /**
 355          * Add an associative array of message to the cache
 356          *
 357          * @param array $messages An associative array of key => values to be added
 358          */
 359         function addMessages( $messages ) {
 360                 foreach ( $messages as $key => $value ) {
 361                         $this->addMessage( $key, $value );
 362                 }
 363         }
 364
 365         /**
 366          * Clear all stored messages. Mainly used after a mass rebuild.
 367          */
 368         function clear() {
 369                 if( $this->mUseCache ) {
 370                         $this->mMemc->delete( $this->mMemcKey );
 371                 }
 372         }
 373 }
 374 ?>