includes/MessageCache.php

   1 <?php
   2 /**
   3  *
   4  * @package MediaWiki
   5  */
   6
   7 /**
   8  *
   9  */
  10 define( 'MSG_LOAD_TIMEOUT', 60);
  11 define( 'MSG_LOCK_TIMEOUT', 10);
  12 define( 'MSG_WAIT_TIMEOUT', 10);
  13
  14 /**
  15  * Message cache
  16  * Performs various useful MediaWiki namespace-related functions
  17  *
  18  * @package MediaWiki
  19  */
  20 class MessageCache
  21 {
  22         var $mCache, $mUseCache, $mDisable, $mExpiry;
  23         var $mMemcKey, $mKeys, $mParserOptions, $mParser;
  24         var $mExtensionMessages;
  25         var $mInitialised = false;
  26         var $mDeferred = true;
  27
  28         function initialise( &$memCached, $useDB, $expiry, $memcPrefix) {
  29                 $fname = 'MessageCache::initialise';
  30                 wfProfileIn( $fname );
  31
  32                 $this->mUseCache = !is_null( $memCached );
  33                 $this->mMemc = &$memCached;
  34                 $this->mDisable = !$useDB;
  35                 $this->mExpiry = $expiry;
  36                 $this->mDisableTransform = false;
  37                 $this->mMemcKey = $memcPrefix.':messages';
  38                 $this->mKeys = false; # initialised on demand
  39                 $this->mInitialised = true;
  40
  41                 wfProfileIn( $fname.'-parseropt' );
  42                 $this->mParserOptions = ParserOptions::newFromUser( $u=NULL );
  43                 wfProfileOut( $fname.'-parseropt' );
  44                 wfProfileIn( $fname.'-parser' );
  45                 $this->mParser = new Parser;
  46                 wfProfileOut( $fname.'-parser' );
  47
  48                 # When we first get asked for a message,
  49                 # then we'll fill up the cache. If we
  50                 # can return a cache hit, this saves
  51                 # some extra milliseconds
  52                 $this->mDeferred = true;
  53
  54                 wfProfileOut( $fname );
  55         }
  56
  57         /**
  58          * Loads messages either from memcached or the database, if not disabled
  59          * On error, quietly switches to a fallback mode
  60          * Returns false for a reportable error, true otherwise
  61          */
  62         function load() {
  63                 global $wgAllMessagesEn;
  64
  65                 if ( $this->mDisable ) {
  66                         wfDebug( "MessageCache::load(): disabled\n" );
  67                         return true;
  68                 }
  69                 $fname = 'MessageCache::load';
  70                 wfProfileIn( $fname );
  71                 $success = true;
  72
  73                 if ( $this->mUseCache ) {
  74                         wfProfileIn( $fname.'-fromcache' );
  75                         $this->mCache = $this->mMemc->get( $this->mMemcKey );
  76                         wfProfileOut( $fname.'-fromcache' );
  77
  78                         # If there's nothing in memcached, load all the messages from the database
  79                         if ( !$this->mCache ) {
  80                                 wfDebug( "MessageCache::load(): loading all messages\n" );
  81                                 $this->lock();
  82                                 # Other threads don't need to load the messages if another thread is doing it.
  83                                 $success = $this->mMemc->add( $this->mMemcKey, "loading", MSG_LOAD_TIMEOUT );
  84                                 if ( $success ) {
  85                                         wfProfileIn( $fname.'-load' );
  86                                         $this->loadFromDB();
  87                                         wfProfileOut( $fname.'-load' );
  88                                         # Save in memcached
  89                                         # Keep trying if it fails, this is kind of important
  90                                         wfProfileIn( $fname.'-save' );
  91                                         for ( $i=0; $i<20 && !$this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry ); $i++ ) {
  92                                                 usleep(mt_rand(500000,1500000));
  93                                         }
  94                                         wfProfileOut( $fname.'-save' );
  95                                         if ( $i == 20 ) {
  96                                                 $this->mMemc->set( $this->mMemcKey, 'error', 86400 );
  97                                                 wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
  98                                         }
  99                                 }
 100                                 $this->unlock();
 101                         }
 102
 103                         if ( !is_array( $this->mCache ) ) {
 104                                 wfDebug( "MessageCache::load(): individual message mode\n" );
 105                                 # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
 106                                 # Causing too much DB load, disabling -- TS
 107                                 $this->mDisable = true;
 108                                 /*
 109                                 if ( $this->mCache == "loading" ) {
 110                                         $this->mUseCache = false;
 111                                 } elseif ( $this->mCache == "error" ) {
 112                                         $this->mUseCache = false;
 113                                         $success = false;
 114                                 } else {
 115                                         $this->mDisable = true;
 116                                         $success = false;
 117                                 }*/
 118                                 $this->mCache = false;
 119                         }
 120                 }
 121                 wfProfileOut( $fname );
 122                 $this->mDeferred = false;
 123                 return $success;
 124         }
 125
 126         /**
 127          * Loads all or main part of cacheable messages from the database
 128          */
 129         function loadFromDB() {
 130                 global $wgPartialMessageCache;
 131                 $fname = 'MessageCache::loadFromDB';
 132                 $dbr =& wfGetDB( DB_SLAVE );
 133                 $conditions = array( 'page_is_redirect' => 0,
 134                                         'page_namespace' => NS_MEDIAWIKI);
 135                 if ($wgPartialMessageCache) {
 136                         wfDebugDieBacktrace( "Confused about how this works." );
 137                         if (is_array($wgPartialMessageCache)) {
 138                                 $conditions['page_title']=$wgPartialMessageCache;
 139                         } else {
 140                                 require_once("MessageCacheHints.php");
 141                                 $conditions['page_title']=MessageCacheHints::get();
 142                         }
 143                 }
 144                 $res = $dbr->select( array( 'page', 'text' ),
 145                         array( 'page_title', 'old_text', 'old_flags' ),
 146                         'page_is_redirect=0 AND page_namespace = '.NS_MEDIAWIKI.' AND page_latest = 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] = Article::getRevisionText( $row );
 153                 }
 154
 155                 $dbr->freeResult( $res );
 156         }
 157
 158         /**
 159          * Not really needed anymore
 160          */
 161         function getKeys() {
 162                 global $wgAllMessagesEn, $wgContLang;
 163                 if ( !$this->mKeys ) {
 164                         $this->mKeys = array();
 165                         foreach ( $wgAllMessagesEn as $key => $value ) {
 166                                 global $wgCapitalLinks;
 167                                 $title = $wgCapitalLinks ? $wgContLang->ucfirst( $key ) : $key;
 168                                 array_push( $this->mKeys, $title );
 169                         }
 170                 }
 171                 return $this->mKeys;
 172         }
 173
 174         /**
 175          * Obsolete
 176          */
 177         function isCacheable( $key ) {
 178                 return true;
 179         }
 180
 181         function replace( $title, $text ) {
 182                 $this->lock();
 183                 $this->load();
 184                 if ( is_array( $this->mCache ) ) {
 185                         $this->mCache[$title] = $text;
 186                         $this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 187                 }
 188                 $this->unlock();
 189         }
 190
 191         /**
 192          * Returns success
 193          * Represents a write lock on the messages key
 194          */
 195         function lock() {
 196                 if ( !$this->mUseCache ) {
 197                         return true;
 198                 }
 199
 200                 $lockKey = $this->mMemcKey . 'lock';
 201                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 202                         sleep(1);
 203                 }
 204
 205                 return $i >= MSG_WAIT_TIMEOUT;
 206         }
 207
 208         function unlock() {
 209                 if ( !$this->mUseCache ) {
 210                         return;
 211                 }
 212
 213                 $lockKey = $this->mMemcKey . 'lock';
 214                 $this->mMemc->delete( $lockKey );
 215         }
 216
 217         function get( $key, $useDB, $forcontent=true ) {
 218                 global $wgContLanguageCode;
 219                 if( $forcontent ) {
 220                         global $wgContLang;
 221                         $lang =& $wgContLang;
 222                         $langcode = $wgContLanguageCode;
 223                 } else {
 224                         global $wgLang, $wgLanguageCode;
 225                         $lang =& $wgLang;
 226                         $langcode = $wgLanguageCode;
 227                 }
 228                 # If uninitialised, someone is trying to call this halfway through Setup.php
 229                 if( !$this->mInitialised ) {
 230                         return "&lt;$key&gt;";
 231                 }
 232                 # If cache initialization was deferred, start it now.
 233                 if( $this->mDeferred ) {
 234                         $this->load();
 235                 }
 236
 237                 $message = false;
 238                 if( !$this->mDisable && $useDB ) {
 239                         global $wgCapitalLinks;
 240                         $title = $wgCapitalLinks ? $lang->ucfirst( $key ) : $key;
 241                         if( $langcode != $wgContLanguageCode ) {
 242                                 $title .= '/' . $langcode;
 243                         }
 244
 245                         # Try the cache
 246                         if( $this->mUseCache && is_array( $this->mCache ) && array_key_exists( $title, $this->mCache ) ) {
 247                                 $message = $this->mCache[$title];
 248                         }
 249
 250                         if ( !$message && $this->mUseCache ) {
 251                                 $message = $this->mMemc->get( $this->mMemcKey . ':' . $title );
 252                                 if( $message ) {
 253                                         $this->mCache[$title] = $message;
 254                                 }
 255                         }
 256
 257                         # If it wasn't in the cache, load each message from the DB individually
 258                         if ( !$message ) {
 259                                 $dbr =& wfGetDB( DB_SLAVE );
 260                                 $result = $dbr->selectRow( array( 'page', 'text' ),
 261                                   array( 'old_flags', 'old_text' ),
 262                                   'page_namespace=' . NS_MEDIAWIKI .
 263                                   ' AND page_title=' . $dbr->addQuotes( $title ) .
 264                                   ' AND page_latest=old_id',
 265                                   'MessageCache::get' );
 266                                 if ( $result ) {
 267                                         $message = Article::getRevisionText( $result );
 268                                         if ($this->mUseCache) {
 269                                                 $this->mCache[$title]=$message;
 270                                                 /* individual messages may be often
 271                                                    recached until proper purge code exists
 272                                                 */
 273                                                 $this->mMemc->set( $this->mMemcKey . ':' . $title, $message, 300 );
 274                                         }
 275                                 }
 276                         }
 277                 }
 278                 # Try the extension array
 279                 if( !$message ) {
 280                         $message = @$this->mExtensionMessages[$key];
 281                 }
 282
 283                 # Try the array in the language object
 284                 if( !$message ) {
 285                         wfSuppressWarnings();
 286                         $message = $lang->getMessage( $key );
 287                         wfRestoreWarnings();
 288                 }
 289
 290                 # Try the English array
 291                 if( !$message && $langcode != 'en' ) {
 292                         wfSuppressWarnings();
 293                         $message = Language::getMessage( $key );
 294                         wfRestoreWarnings();
 295                 }
 296
 297                 # Final fallback
 298                 if( !$message ) {
 299                         $message = "&lt;$key&gt;";
 300                 }
 301
 302                 # Replace brace tags
 303                 $message = $this->transform( $message );
 304                 return $message;
 305         }
 306
 307         function transform( $message ) {
 308                 if( !$this->mDisableTransform ) {
 309                         if( strpos( $message, '{{' ) !== false ) {
 310                                 $message = $this->mParser->transformMsg( $message, $this->mParserOptions );
 311                         }
 312                 }
 313                 return $message;
 314         }
 315
 316         function disable() { $this->mDisable = true; }
 317         function enable() { $this->mDisable = false; }
 318         function disableTransform() { $this->mDisableTransform = true; }
 319         function enableTransform() { $this->mDisableTransform = false; }
 320
 321         function addMessage( $key, $value ) {
 322                 $this->mExtensionMessages[$key] = $value;
 323         }
 324
 325         function addMessages( $messages ) {
 326                 foreach ( $messages as $key => $value ) {
 327                         $this->mExtensionMessages[$key] = $value;
 328                 }
 329         }
 330
 331         /**
 332          * Clear all stored messages. Mainly used after a mass rebuild.
 333          */
 334         function clear() {
 335                 if( $this->mUseCache ) {
 336                         $this->mMemc->delete( $this->mMemcKey );
 337                 }
 338         }
 339 }
 340 ?>