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;
  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                         wfDebug( "MessageCache::load(): disabled\n" );
  71                         return true;
  72                 }
  73                 $fname = 'MessageCache::load';
  74                 wfProfileIn( $fname );
  75                 $success = true;
  76
  77                 if ( $this->mUseCache ) {
  78                         wfProfileIn( $fname.'-fromcache' );
  79                         $this->mCache = $this->mMemc->get( $this->mMemcKey );
  80                         wfProfileOut( $fname.'-fromcache' );
  81
  82                         # If there's nothing in memcached, load all the messages from the database
  83                         if ( !$this->mCache ) {
  84                                 wfDebug( "MessageCache::load(): loading all messages\n" );
  85                                 $this->lock();
  86                                 # Other threads don't need to load the messages if another thread is doing it.
  87                                 $success = $this->mMemc->add( $this->mMemcKey, "loading", MSG_LOAD_TIMEOUT );
  88                                 if ( $success ) {
  89                                         wfProfileIn( $fname.'-load' );
  90                                         $this->loadFromDB();
  91                                         wfProfileOut( $fname.'-load' );
  92                                         # Save in memcached
  93                                         # Keep trying if it fails, this is kind of important
  94                                         wfProfileIn( $fname.'-save' );
  95                                         for ( $i=0; $i<20 && !$this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry ); $i++ ) {
  96                                                 usleep(mt_rand(500000,1500000));
  97                                         }
  98                                         wfProfileOut( $fname.'-save' );
  99                                         if ( $i == 20 ) {
 100                                                 $this->mMemc->set( $this->mMemcKey, 'error', 60*5 );
 101                                                 wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 102                                         }
 103                                 }
 104                                 $this->unlock();
 105                         }
 106
 107                         if ( !is_array( $this->mCache ) ) {
 108                                 wfDebug( "MessageCache::load(): individual message mode\n" );
 109                                 # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
 110                                 # Causing too much DB load, disabling -- TS
 111                                 $this->mDisable = true;
 112                                 /*
 113                                 if ( $this->mCache == "loading" ) {
 114                                         $this->mUseCache = false;
 115                                 } elseif ( $this->mCache == "error" ) {
 116                                         $this->mUseCache = false;
 117                                         $success = false;
 118                                 } else {
 119                                         $this->mDisable = true;
 120                                         $success = false;
 121                                 }*/
 122                                 $this->mCache = false;
 123                         }
 124                 }
 125                 wfProfileOut( $fname );
 126                 $this->mDeferred = false;
 127                 return $success;
 128         }
 129
 130         /**
 131          * Loads all or main part of cacheable messages from the database
 132          */
 133         function loadFromDB() {
 134                 $fname = 'MessageCache::loadFromDB';
 135                 $dbr =& wfGetDB( DB_SLAVE );
 136                 $conditions = array( 'page_is_redirect' => 0,
 137                                         'page_namespace' => NS_MEDIAWIKI);
 138                 $res = $dbr->select( array( 'page', 'revision', 'text' ),
 139                         array( 'page_title', 'old_text', 'old_flags' ),
 140                         'page_is_redirect=0 AND page_namespace='.NS_MEDIAWIKI.' AND page_latest=rev_id AND rev_text_id=old_id',
 141                         $fname
 142                 );
 143
 144                 $this->mCache = array();
 145                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 146                         $this->mCache[$row->page_title] = Revision::getRevisionText( $row );
 147                 }
 148
 149                 $dbr->freeResult( $res );
 150                 /*
 151                 # FIXME: This is too slow currently.
 152                 # We need to bulk-fetch revisions, but in a portable way...
 153                 $resultSet = Revision::fetchFromConds( $dbr, array(
 154                         'page_namespace'   => NS_MEDIAWIKI,
 155                         'page_is_redirect' => 0,
 156                         'page_id=rev_page' ) );
 157                 while( $row = $resultSet->fetchObject() ) {
 158                         $revision = new Revision( $row );
 159                         $title = $revision->getTitle();
 160                         $this->mCache[$title->getDBkey()] = $revision->getText();
 161                 }
 162                 $resultSet->free();
 163                 */
 164         }
 165
 166         /**
 167          * Not really needed anymore
 168          */
 169         function getKeys() {
 170                 global $wgAllMessagesEn, $wgContLang;
 171                 if ( !$this->mKeys ) {
 172                         $this->mKeys = array();
 173                         foreach ( $wgAllMessagesEn as $key => $value ) {
 174                                 $title = $wgContLang->ucfirst( $key );
 175                                 array_push( $this->mKeys, $title );
 176                         }
 177                 }
 178                 return $this->mKeys;
 179         }
 180
 181         /**
 182          * Obsolete
 183          */
 184         function isCacheable( $key ) {
 185                 return true;
 186         }
 187
 188         function replace( $title, $text ) {
 189                 $this->lock();
 190                 $this->load();
 191                 if ( is_array( $this->mCache ) ) {
 192                         $this->mCache[$title] = $text;
 193                         $this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 194                 }
 195                 $this->unlock();
 196         }
 197
 198         /**
 199          * Returns success
 200          * Represents a write lock on the messages key
 201          */
 202         function lock() {
 203                 if ( !$this->mUseCache ) {
 204                         return true;
 205                 }
 206
 207                 $lockKey = $this->mMemcKey . 'lock';
 208                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 209                         sleep(1);
 210                 }
 211
 212                 return $i >= MSG_WAIT_TIMEOUT;
 213         }
 214
 215         function unlock() {
 216                 if ( !$this->mUseCache ) {
 217                         return;
 218                 }
 219
 220                 $lockKey = $this->mMemcKey . 'lock';
 221                 $this->mMemc->delete( $lockKey );
 222         }
 223
 224         function get( $key, $useDB, $forcontent=true, $isfullkey = false ) {
 225                 global $wgContLanguageCode;
 226                 if( $forcontent ) {
 227                         global $wgContLang;
 228                         $lang =& $wgContLang;
 229                         $langcode = $wgContLanguageCode;
 230                 } else {
 231                         global $wgLang, $wgLanguageCode;
 232                         $lang =& $wgLang;
 233                         $langcode = $wgLanguageCode;
 234                 }
 235                 # If uninitialised, someone is trying to call this halfway through Setup.php
 236                 if( !$this->mInitialised ) {
 237                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 238                 }
 239                 # If cache initialization was deferred, start it now.
 240                 if( $this->mDeferred ) {
 241                         $this->load();
 242                 }
 243
 244                 $message = false;
 245                 if( !$this->mDisable && $useDB ) {
 246                         $title = $lang->ucfirst( $key );
 247                         if(!$isfullkey && ($langcode != $wgContLanguageCode) ) {
 248                                 $title .= '/' . $langcode;
 249                         }
 250                         $message = $this->getFromCache( $title );
 251                 }
 252                 # Try the extension array
 253                 if( !$message ) {
 254                         $message = @$this->mExtensionMessages[$key];
 255                 }
 256
 257                 # Try the array in the language object
 258                 if( !$message ) {
 259                         wfSuppressWarnings();
 260                         $message = $lang->getMessage( $key );
 261                         wfRestoreWarnings();
 262                 }
 263
 264                 # Try the English array
 265                 if( !$message && $langcode != 'en' ) {
 266                         wfSuppressWarnings();
 267                         $message = Language::getMessage( $key );
 268                         wfRestoreWarnings();
 269                 }
 270
 271                 # Is this a custom message? Try the default language in the db...
 272                 if( !$message &&
 273                         !$this->mDisable && $useDB &&
 274                         !$isfullkey && ($langcode != $wgContLanguageCode) ) {
 275                         $message = $this->getFromCache( $lang->ucfirst( $key ) );
 276                 }
 277
 278                 # Final fallback
 279                 if( !$message ) {
 280                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 281                 }
 282
 283                 # Replace brace tags
 284                 $message = $this->transform( $message );
 285                 return $message;
 286         }
 287
 288         function getFromCache( $title ) {
 289                 $message = false;
 290
 291                 # Try the cache
 292                 if( $this->mUseCache && is_array( $this->mCache ) && array_key_exists( $title, $this->mCache ) ) {
 293                         $message = $this->mCache[$title];
 294                 }
 295
 296                 if ( !$message && $this->mUseCache ) {
 297                         $message = $this->mMemc->get( $this->mMemcKey . ':' . $title );
 298                         if( $message ) {
 299                                 $this->mCache[$title] = $message;
 300                         }
 301                 }
 302
 303                 # If it wasn't in the cache, load each message from the DB individually
 304                 if ( !$message ) {
 305                         $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 306                         if( $revision ) {
 307                                 $message = $revision->getText();
 308                                 if ($this->mUseCache) {
 309                                         $this->mCache[$title]=$message;
 310                                         /* individual messages may be often
 311                                            recached until proper purge code exists
 312                                         */
 313                                         $this->mMemc->set( $this->mMemcKey . ':' . $title, $message, 300 );
 314                                 }
 315                         }
 316                 }
 317
 318                 return $message;
 319         }
 320
 321         function transform( $message ) {
 322                 if( !$this->mDisableTransform ) {
 323                         if( strpos( $message, '{{' ) !== false ) {
 324                                 $message = $this->mParser->transformMsg( $message, $this->mParserOptions );
 325                         }
 326                 }
 327                 return $message;
 328         }
 329
 330         function disable() { $this->mDisable = true; }
 331         function enable() { $this->mDisable = false; }
 332         function disableTransform() { $this->mDisableTransform = true; }
 333         function enableTransform() { $this->mDisableTransform = false; }
 334
 335         function addMessage( $key, $value ) {
 336                 $this->mExtensionMessages[$key] = $value;
 337         }
 338
 339         function addMessages( $messages ) {
 340                 foreach ( $messages as $key => $value ) {
 341                         $this->mExtensionMessages[$key] = $value;
 342                 }
 343         }
 344
 345         /**
 346          * Clear all stored messages. Mainly used after a mass rebuild.
 347          */
 348         function clear() {
 349                 if( $this->mUseCache ) {
 350                         $this->mMemc->delete( $this->mMemcKey );
 351                 }
 352         }
 353 }
 354 ?>