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                         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, "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; $i<20 && !$this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry ); $i++ ) {
 100                                                 usleep(mt_rand(500000,1500000));
 101                                         }
 102                                         wfProfileOut( $fname.'-save' );
 103                                         if ( $i == 20 ) {
 104                                                 $this->mMemc->set( $this->mMemcKey, 'error', 60*5 );
 105                                                 wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 106                                         }
 107                                 }
 108                                 $this->unlock();
 109                         }
 110
 111                         if ( !is_array( $this->mCache ) ) {
 112                                 wfDebug( "MessageCache::load(): individual message mode\n" );
 113                                 # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
 114                                 # Causing too much DB load, disabling -- TS
 115                                 $this->mDisable = true;
 116                                 /*
 117                                 if ( $this->mCache == "loading" ) {
 118                                         $this->mUseCache = false;
 119                                 } elseif ( $this->mCache == "error" ) {
 120                                         $this->mUseCache = false;
 121                                         $success = false;
 122                                 } else {
 123                                         $this->mDisable = true;
 124                                         $success = false;
 125                                 }*/
 126                                 $this->mCache = false;
 127                         }
 128                 }
 129                 wfProfileOut( $fname );
 130                 $this->mDeferred = false;
 131                 return $success;
 132         }
 133
 134         /**
 135          * Loads all or main part of cacheable messages from the database
 136          */
 137         function loadFromDB() {
 138                 $fname = 'MessageCache::loadFromDB';
 139                 $dbr =& wfGetDB( DB_SLAVE );
 140                 $conditions = array( 'page_is_redirect' => 0,
 141                                         'page_namespace' => NS_MEDIAWIKI);
 142                 $res = $dbr->select( array( 'page', 'revision', 'text' ),
 143                         array( 'page_title', 'old_text', 'old_flags' ),
 144                         'page_is_redirect=0 AND page_namespace='.NS_MEDIAWIKI.' AND page_latest=rev_id AND rev_text_id=old_id',
 145                         $fname
 146                 );
 147
 148                 $this->mCache = array();
 149                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 150                         $this->mCache[$row->page_title] = Revision::getRevisionText( $row );
 151                 }
 152
 153                 $dbr->freeResult( $res );
 154                 /*
 155                 # FIXME: This is too slow currently.
 156                 # We need to bulk-fetch revisions, but in a portable way...
 157                 $resultSet = Revision::fetchFromConds( $dbr, array(
 158                         'page_namespace'   => NS_MEDIAWIKI,
 159                         'page_is_redirect' => 0,
 160                         'page_id=rev_page' ) );
 161                 while( $row = $resultSet->fetchObject() ) {
 162                         $revision = new Revision( $row );
 163                         $title = $revision->getTitle();
 164                         $this->mCache[$title->getDBkey()] = $revision->getText();
 165                 }
 166                 $resultSet->free();
 167                 */
 168         }
 169
 170         /**
 171          * Not really needed anymore
 172          */
 173         function getKeys() {
 174                 global $wgAllMessagesEn, $wgContLang;
 175                 if ( !$this->mKeys ) {
 176                         $this->mKeys = array();
 177                         foreach ( $wgAllMessagesEn as $key => $value ) {
 178                                 $title = $wgContLang->ucfirst( $key );
 179                                 array_push( $this->mKeys, $title );
 180                         }
 181                 }
 182                 return $this->mKeys;
 183         }
 184
 185         /**
 186          * Obsolete
 187          */
 188         function isCacheable( $key ) {
 189                 return true;
 190         }
 191
 192         function replace( $title, $text ) {
 193                 $this->lock();
 194                 $this->load();
 195                 if ( is_array( $this->mCache ) ) {
 196                         $this->mCache[$title] = $text;
 197                         $this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 198                 }
 199                 $this->unlock();
 200         }
 201
 202         /**
 203          * Returns success
 204          * Represents a write lock on the messages key
 205          */
 206         function lock() {
 207                 if ( !$this->mUseCache ) {
 208                         return true;
 209                 }
 210
 211                 $lockKey = $this->mMemcKey . 'lock';
 212                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 213                         sleep(1);
 214                 }
 215
 216                 return $i >= MSG_WAIT_TIMEOUT;
 217         }
 218
 219         function unlock() {
 220                 if ( !$this->mUseCache ) {
 221                         return;
 222                 }
 223
 224                 $lockKey = $this->mMemcKey . 'lock';
 225                 $this->mMemc->delete( $lockKey );
 226         }
 227
 228         function get( $key, $useDB, $forcontent=true, $isfullkey = false ) {
 229                 global $wgContLanguageCode;
 230                 if( $forcontent ) {
 231                         global $wgContLang;
 232                         $lang =& $wgContLang;
 233                         $langcode = $wgContLanguageCode;
 234                 } else {
 235                         global $wgLang, $wgLanguageCode;
 236                         $lang =& $wgLang;
 237                         $langcode = $wgLanguageCode;
 238                 }
 239                 # If uninitialised, someone is trying to call this halfway through Setup.php
 240                 if( !$this->mInitialised ) {
 241                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 242                 }
 243                 # If cache initialization was deferred, start it now.
 244                 if( $this->mDeferred ) {
 245                         $this->load();
 246                 }
 247
 248                 $message = false;
 249                 if( !$this->mDisable && $useDB ) {
 250                         $title = $lang->ucfirst( $key );
 251                         if(!$isfullkey && ($langcode != $wgContLanguageCode) ) {
 252                                 $title .= '/' . $langcode;
 253                         }
 254                         $message = $this->getFromCache( $title );
 255                 }
 256                 # Try the extension array
 257                 if( !$message ) {
 258                         $message = @$this->mExtensionMessages[$key];
 259                 }
 260
 261                 # Try the array in the language object
 262                 if( !$message ) {
 263                         wfSuppressWarnings();
 264                         $message = $lang->getMessage( $key );
 265                         wfRestoreWarnings();
 266                 }
 267
 268                 # Try the English array
 269                 if( !$message && $langcode != 'en' ) {
 270                         wfSuppressWarnings();
 271                         $message = Language::getMessage( $key );
 272                         wfRestoreWarnings();
 273                 }
 274
 275                 # Is this a custom message? Try the default language in the db...
 276                 if( !$message &&
 277                         !$this->mDisable && $useDB &&
 278                         !$isfullkey && ($langcode != $wgContLanguageCode) ) {
 279                         $message = $this->getFromCache( $lang->ucfirst( $key ) );
 280                 }
 281
 282                 # Final fallback
 283                 if( !$message ) {
 284                         return '&lt;' . htmlspecialchars($key) . '&gt;';
 285                 }
 286
 287                 # Replace brace tags
 288                 $message = $this->transform( $message );
 289                 return $message;
 290         }
 291
 292         function getFromCache( $title ) {
 293                 $message = false;
 294
 295                 # Try the cache
 296                 if( $this->mUseCache && is_array( $this->mCache ) && array_key_exists( $title, $this->mCache ) ) {
 297                         $message = $this->mCache[$title];
 298                 }
 299
 300                 if ( !$message && $this->mUseCache ) {
 301                         $message = $this->mMemc->get( $this->mMemcKey . ':' . $title );
 302                         if( $message ) {
 303                                 $this->mCache[$title] = $message;
 304                         }
 305                 }
 306
 307                 # If it wasn't in the cache, load each message from the DB individually
 308                 if ( !$message ) {
 309                         $revision = Revision::newFromTitle( Title::makeTitle( NS_MEDIAWIKI, $title ) );
 310                         if( $revision ) {
 311                                 $message = $revision->getText();
 312                                 if ($this->mUseCache) {
 313                                         $this->mCache[$title]=$message;
 314                                         /* individual messages may be often
 315                                            recached until proper purge code exists
 316                                         */
 317                                         $this->mMemc->set( $this->mMemcKey . ':' . $title, $message, 300 );
 318                                 }
 319                         }
 320                 }
 321
 322                 return $message;
 323         }
 324
 325         function transform( $message ) {
 326                 if( !$this->mDisableTransform ) {
 327                         if( strpos( $message, '{{' ) !== false ) {
 328                                 $message = $this->mParser->transformMsg( $message, $this->mParserOptions );
 329                         }
 330                 }
 331                 return $message;
 332         }
 333
 334         function disable() { $this->mDisable = true; }
 335         function enable() { $this->mDisable = false; }
 336         function disableTransform() { $this->mDisableTransform = true; }
 337         function enableTransform() { $this->mDisableTransform = false; }
 338
 339         function addMessage( $key, $value ) {
 340                 $this->mExtensionMessages[$key] = $value;
 341         }
 342
 343         function addMessages( $messages ) {
 344                 foreach ( $messages as $key => $value ) {
 345                         $this->mExtensionMessages[$key] = $value;
 346                 }
 347         }
 348
 349         /**
 350          * Clear all stored messages. Mainly used after a mass rebuild.
 351          */
 352         function clear() {
 353                 if( $this->mUseCache ) {
 354                         $this->mMemc->delete( $this->mMemcKey );
 355                 }
 356         }
 357 }
 358 ?>