includes/MessageCache.php

   1 <?php
   2 /**
   3  *
   4  * @package MediaWiki
   5  */
   6
   7 require_once( 'Revision.php' );
   8
   9 /**
  10  *
  11  */
  12 define( 'MSG_LOAD_TIMEOUT', 60);
  13 define( 'MSG_LOCK_TIMEOUT', 10);
  14 define( 'MSG_WAIT_TIMEOUT', 10);
  15
  16 /**
  17  * Message cache
  18  * Performs various useful MediaWiki namespace-related functions
  19  *
  20  * @package MediaWiki
  21  */
  22 class MessageCache
  23 {
  24         var $mCache, $mUseCache, $mDisable, $mExpiry;
  25         var $mMemcKey, $mKeys, $mParserOptions, $mParser;
  26         var $mExtensionMessages;
  27         var $mInitialised = false;
  28         var $mDeferred = true;
  29
  30         function initialise( &$memCached, $useDB, $expiry, $memcPrefix) {
  31                 $fname = 'MessageCache::initialise';
  32                 wfProfileIn( $fname );
  33
  34                 $this->mUseCache = !is_null( $memCached );
  35                 $this->mMemc = &$memCached;
  36                 $this->mDisable = !$useDB;
  37                 $this->mExpiry = $expiry;
  38                 $this->mDisableTransform = false;
  39                 $this->mMemcKey = $memcPrefix.':messages';
  40                 $this->mKeys = false; # initialised on demand
  41                 $this->mInitialised = true;
  42
  43                 wfProfileIn( $fname.'-parseropt' );
  44                 $this->mParserOptions = ParserOptions::newFromUser( $u=NULL );
  45                 wfProfileOut( $fname.'-parseropt' );
  46                 wfProfileIn( $fname.'-parser' );
  47                 $this->mParser = new Parser;
  48                 wfProfileOut( $fname.'-parser' );
  49
  50                 # When we first get asked for a message,
  51                 # then we'll fill up the cache. If we
  52                 # can return a cache hit, this saves
  53                 # some extra milliseconds
  54                 $this->mDeferred = true;
  55
  56                 wfProfileOut( $fname );
  57         }
  58
  59         /**
  60          * Loads messages either from memcached or the database, if not disabled
  61          * On error, quietly switches to a fallback mode
  62          * Returns false for a reportable error, true otherwise
  63          */
  64         function load() {
  65                 global $wgAllMessagesEn;
  66
  67                 if ( $this->mDisable ) {
  68                         wfDebug( "MessageCache::load(): disabled\n" );
  69                         return true;
  70                 }
  71                 $fname = 'MessageCache::load';
  72                 wfProfileIn( $fname );
  73                 $success = true;
  74
  75                 if ( $this->mUseCache ) {
  76                         wfProfileIn( $fname.'-fromcache' );
  77                         $this->mCache = $this->mMemc->get( $this->mMemcKey );
  78                         wfProfileOut( $fname.'-fromcache' );
  79
  80                         # If there's nothing in memcached, load all the messages from the database
  81                         if ( !$this->mCache ) {
  82                                 wfDebug( "MessageCache::load(): loading all messages\n" );
  83                                 $this->lock();
  84                                 # Other threads don't need to load the messages if another thread is doing it.
  85                                 $success = $this->mMemc->add( $this->mMemcKey, "loading", MSG_LOAD_TIMEOUT );
  86                                 if ( $success ) {
  87                                         wfProfileIn( $fname.'-load' );
  88                                         $this->loadFromDB();
  89                                         wfProfileOut( $fname.'-load' );
  90                                         # Save in memcached
  91                                         # Keep trying if it fails, this is kind of important
  92                                         wfProfileIn( $fname.'-save' );
  93                                         for ( $i=0; $i<20 && !$this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry ); $i++ ) {
  94                                                 usleep(mt_rand(500000,1500000));
  95                                         }
  96                                         wfProfileOut( $fname.'-save' );
  97                                         if ( $i == 20 ) {
  98                                                 $this->mMemc->set( $this->mMemcKey, 'error', 86400 );
  99                                                 wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 100                                         }
 101                                 }
 102                                 $this->unlock();
 103                         }
 104
 105                         if ( !is_array( $this->mCache ) ) {
 106                                 wfDebug( "MessageCache::load(): individual message mode\n" );
 107                                 # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
 108                                 # Causing too much DB load, disabling -- TS
 109                                 $this->mDisable = true;
 110                                 /*
 111                                 if ( $this->mCache == "loading" ) {
 112                                         $this->mUseCache = false;
 113                                 } elseif ( $this->mCache == "error" ) {
 114                                         $this->mUseCache = false;
 115                                         $success = false;
 116                                 } else {
 117                                         $this->mDisable = true;
 118                                         $success = false;
 119                                 }*/
 120                                 $this->mCache = false;
 121                         }
 122                 }
 123                 wfProfileOut( $fname );
 124                 $this->mDeferred = false;
 125                 return $success;
 126         }
 127
 128         /**
 129          * Loads all or main part of cacheable messages from the database
 130          */
 131         function loadFromDB() {
 132                 global $wgPartialMessageCache;
 133                 $fname = 'MessageCache::loadFromDB';
 134                 $dbr =& wfGetDB( DB_SLAVE );
 135                 $conditions = array( 'page_is_redirect' => 0,
 136                                         'page_namespace' => NS_MEDIAWIKI);
 137                 if ($wgPartialMessageCache) {
 138                         wfDebugDieBacktrace( "Confused about how this works." );
 139                         if (is_array($wgPartialMessageCache)) {
 140                                 $conditions['page_title']=$wgPartialMessageCache;
 141                         } else {
 142                                 require_once("MessageCacheHints.php");
 143                                 $conditions['page_title']=MessageCacheHints::get();
 144                         }
 145                 }
 146                 $res = $dbr->select( array( 'page', 'text' ),
 147                         array( 'page_title', 'old_text', 'old_flags' ),
 148                         'page_is_redirect=0 AND page_namespace = '.NS_MEDIAWIKI.' AND page_latest = old_id',
 149                         $fname
 150                 );
 151
 152                 $this->mCache = array();
 153                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 154                         $this->mCache[$row->page_title] = Revision::getRevisionText( $row );
 155                 }
 156
 157                 $dbr->freeResult( $res );
 158         }
 159
 160         /**
 161          * Not really needed anymore
 162          */
 163         function getKeys() {
 164                 global $wgAllMessagesEn, $wgContLang;
 165                 if ( !$this->mKeys ) {
 166                         $this->mKeys = array();
 167                         foreach ( $wgAllMessagesEn as $key => $value ) {
 168                                 global $wgCapitalLinks;
 169                                 $title = $wgCapitalLinks ? $wgContLang->ucfirst( $key ) : $key;
 170                                 array_push( $this->mKeys, $title );
 171                         }
 172                 }
 173                 return $this->mKeys;
 174         }
 175
 176         /**
 177          * Obsolete
 178          */
 179         function isCacheable( $key ) {
 180                 return true;
 181         }
 182
 183         function replace( $title, $text ) {
 184                 $this->lock();
 185                 $this->load();
 186                 if ( is_array( $this->mCache ) ) {
 187                         $this->mCache[$title] = $text;
 188                         $this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 189                 }
 190                 $this->unlock();
 191         }
 192
 193         /**
 194          * Returns success
 195          * Represents a write lock on the messages key
 196          */
 197         function lock() {
 198                 if ( !$this->mUseCache ) {
 199                         return true;
 200                 }
 201
 202                 $lockKey = $this->mMemcKey . 'lock';
 203                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 204                         sleep(1);
 205                 }
 206
 207                 return $i >= MSG_WAIT_TIMEOUT;
 208         }
 209
 210         function unlock() {
 211                 if ( !$this->mUseCache ) {
 212                         return;
 213                 }
 214
 215                 $lockKey = $this->mMemcKey . 'lock';
 216                 $this->mMemc->delete( $lockKey );
 217         }
 218
 219         function get( $key, $useDB, $forcontent=true ) {
 220                 global $wgContLanguageCode;
 221                 if( $forcontent ) {
 222                         global $wgContLang;
 223                         $lang =& $wgContLang;
 224                         $langcode = $wgContLanguageCode;
 225                 } else {
 226                         global $wgLang, $wgLanguageCode;
 227                         $lang =& $wgLang;
 228                         $langcode = $wgLanguageCode;
 229                 }
 230                 # If uninitialised, someone is trying to call this halfway through Setup.php
 231                 if( !$this->mInitialised ) {
 232                         return "&lt;$key&gt;";
 233                 }
 234                 # If cache initialization was deferred, start it now.
 235                 if( $this->mDeferred ) {
 236                         $this->load();
 237                 }
 238
 239                 $message = false;
 240                 if( !$this->mDisable && $useDB ) {
 241                         global $wgCapitalLinks;
 242                         $title = $wgCapitalLinks ? $lang->ucfirst( $key ) : $key;
 243                         if( $langcode != $wgContLanguageCode ) {
 244                                 $title .= '/' . $langcode;
 245                         }
 246
 247                         # Try the cache
 248                         if( $this->mUseCache && is_array( $this->mCache ) && array_key_exists( $title, $this->mCache ) ) {
 249                                 $message = $this->mCache[$title];
 250                         }
 251
 252                         if ( !$message && $this->mUseCache ) {
 253                                 $message = $this->mMemc->get( $this->mMemcKey . ':' . $title );
 254                                 if( $message ) {
 255                                         $this->mCache[$title] = $message;
 256                                 }
 257                         }
 258
 259                         # If it wasn't in the cache, load each message from the DB individually
 260                         if ( !$message ) {
 261                                 $dbr =& wfGetDB( DB_SLAVE );
 262                                 $result = $dbr->selectRow( array( 'page', 'text' ),
 263                                   array( 'old_flags', 'old_text' ),
 264                                   'page_namespace=' . NS_MEDIAWIKI .
 265                                   ' AND page_title=' . $dbr->addQuotes( $title ) .
 266                                   ' AND page_latest=old_id',
 267                                   'MessageCache::get' );
 268                                 if ( $result ) {
 269                                         $message = Revision::getRevisionText( $result );
 270                                         if ($this->mUseCache) {
 271                                                 $this->mCache[$title]=$message;
 272                                                 /* individual messages may be often
 273                                                    recached until proper purge code exists
 274                                                 */
 275                                                 $this->mMemc->set( $this->mMemcKey . ':' . $title, $message, 300 );
 276                                         }
 277                                 }
 278                         }
 279                 }
 280                 # Try the extension array
 281                 if( !$message ) {
 282                         $message = @$this->mExtensionMessages[$key];
 283                 }
 284
 285                 # Try the array in the language object
 286                 if( !$message ) {
 287                         wfSuppressWarnings();
 288                         $message = $lang->getMessage( $key );
 289                         wfRestoreWarnings();
 290                 }
 291
 292                 # Try the English array
 293                 if( !$message && $langcode != 'en' ) {
 294                         wfSuppressWarnings();
 295                         $message = Language::getMessage( $key );
 296                         wfRestoreWarnings();
 297                 }
 298
 299                 # Final fallback
 300                 if( !$message ) {
 301                         $message = "&lt;$key&gt;";
 302                 }
 303
 304                 # Replace brace tags
 305                 $message = $this->transform( $message );
 306                 return $message;
 307         }
 308
 309         function transform( $message ) {
 310                 if( !$this->mDisableTransform ) {
 311                         if( strpos( $message, '{{' ) !== false ) {
 312                                 $message = $this->mParser->transformMsg( $message, $this->mParserOptions );
 313                         }
 314                 }
 315                 return $message;
 316         }
 317
 318         function disable() { $this->mDisable = true; }
 319         function enable() { $this->mDisable = false; }
 320         function disableTransform() { $this->mDisableTransform = true; }
 321         function enableTransform() { $this->mDisableTransform = false; }
 322
 323         function addMessage( $key, $value ) {
 324                 $this->mExtensionMessages[$key] = $value;
 325         }
 326
 327         function addMessages( $messages ) {
 328                 foreach ( $messages as $key => $value ) {
 329                         $this->mExtensionMessages[$key] = $value;
 330                 }
 331         }
 332
 333         /**
 334          * Clear all stored messages. Mainly used after a mass rebuild.
 335          */
 336         function clear() {
 337                 if( $this->mUseCache ) {
 338                         $this->mMemc->delete( $this->mMemcKey );
 339                 }
 340         }
 341 }
 342 ?>