includes/MessageCache.php

   1 <?php
   2 /**
   3  *
   4  * @package MediaWiki
   5  */
   6
   7 /** */
   8 require_once( 'Revision.php' );
   9
  10 /**
  11  *
  12  */
  13 define( 'MSG_LOAD_TIMEOUT', 60);
  14 define( 'MSG_LOCK_TIMEOUT', 10);
  15 define( 'MSG_WAIT_TIMEOUT', 10);
  16
  17 /**
  18  * Message cache
  19  * Performs various useful MediaWiki namespace-related functions
  20  *
  21  * @package MediaWiki
  22  */
  23 class MessageCache
  24 {
  25         var $mCache, $mUseCache, $mDisable, $mExpiry;
  26         var $mMemcKey, $mKeys, $mParserOptions, $mParser;
  27         var $mExtensionMessages;
  28         var $mInitialised = false;
  29         var $mDeferred = true;
  30
  31         function initialise( &$memCached, $useDB, $expiry, $memcPrefix) {
  32                 $fname = 'MessageCache::initialise';
  33                 wfProfileIn( $fname );
  34
  35                 $this->mUseCache = !is_null( $memCached );
  36                 $this->mMemc = &$memCached;
  37                 $this->mDisable = !$useDB;
  38                 $this->mExpiry = $expiry;
  39                 $this->mDisableTransform = false;
  40                 $this->mMemcKey = $memcPrefix.':messages';
  41                 $this->mKeys = false; # initialised on demand
  42                 $this->mInitialised = true;
  43
  44                 wfProfileIn( $fname.'-parseropt' );
  45                 $this->mParserOptions = ParserOptions::newFromUser( $u=NULL );
  46                 wfProfileOut( $fname.'-parseropt' );
  47                 wfProfileIn( $fname.'-parser' );
  48                 $this->mParser = new Parser;
  49                 wfProfileOut( $fname.'-parser' );
  50
  51                 # When we first get asked for a message,
  52                 # then we'll fill up the cache. If we
  53                 # can return a cache hit, this saves
  54                 # some extra milliseconds
  55                 $this->mDeferred = true;
  56
  57                 wfProfileOut( $fname );
  58         }
  59
  60         /**
  61          * Loads messages either from memcached or the database, if not disabled
  62          * On error, quietly switches to a fallback mode
  63          * Returns false for a reportable error, true otherwise
  64          */
  65         function load() {
  66                 global $wgAllMessagesEn;
  67
  68                 if ( $this->mDisable ) {
  69                         wfDebug( "MessageCache::load(): disabled\n" );
  70                         return true;
  71                 }
  72                 $fname = 'MessageCache::load';
  73                 wfProfileIn( $fname );
  74                 $success = true;
  75
  76                 if ( $this->mUseCache ) {
  77                         wfProfileIn( $fname.'-fromcache' );
  78                         $this->mCache = $this->mMemc->get( $this->mMemcKey );
  79                         wfProfileOut( $fname.'-fromcache' );
  80
  81                         # If there's nothing in memcached, load all the messages from the database
  82                         if ( !$this->mCache ) {
  83                                 wfDebug( "MessageCache::load(): loading all messages\n" );
  84                                 $this->lock();
  85                                 # Other threads don't need to load the messages if another thread is doing it.
  86                                 $success = $this->mMemc->add( $this->mMemcKey, "loading", MSG_LOAD_TIMEOUT );
  87                                 if ( $success ) {
  88                                         wfProfileIn( $fname.'-load' );
  89                                         $this->loadFromDB();
  90                                         wfProfileOut( $fname.'-load' );
  91                                         # Save in memcached
  92                                         # Keep trying if it fails, this is kind of important
  93                                         wfProfileIn( $fname.'-save' );
  94                                         for ( $i=0; $i<20 && !$this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry ); $i++ ) {
  95                                                 usleep(mt_rand(500000,1500000));
  96                                         }
  97                                         wfProfileOut( $fname.'-save' );
  98                                         if ( $i == 20 ) {
  99                                                 $this->mMemc->set( $this->mMemcKey, 'error', 60*5 );
 100                                                 wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
 101                                         }
 102                                 }
 103                                 $this->unlock();
 104                         }
 105
 106                         if ( !is_array( $this->mCache ) ) {
 107                                 wfDebug( "MessageCache::load(): individual message mode\n" );
 108                                 # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
 109                                 # Causing too much DB load, disabling -- TS
 110                                 $this->mDisable = true;
 111                                 /*
 112                                 if ( $this->mCache == "loading" ) {
 113                                         $this->mUseCache = false;
 114                                 } elseif ( $this->mCache == "error" ) {
 115                                         $this->mUseCache = false;
 116                                         $success = false;
 117                                 } else {
 118                                         $this->mDisable = true;
 119                                         $success = false;
 120                                 }*/
 121                                 $this->mCache = false;
 122                         }
 123                 }
 124                 wfProfileOut( $fname );
 125                 $this->mDeferred = false;
 126                 return $success;
 127         }
 128
 129         /**
 130          * Loads all or main part of cacheable messages from the database
 131          */
 132         function loadFromDB() {
 133                 global $wgPartialMessageCache;
 134                 $fname = 'MessageCache::loadFromDB';
 135                 $dbr =& wfGetDB( DB_SLAVE );
 136                 $conditions = array( 'page_is_redirect' => 0,
 137                                         'page_namespace' => NS_MEDIAWIKI);
 138                 if ($wgPartialMessageCache) {
 139                         wfDebugDieBacktrace( "Confused about how this works." );
 140                         if (is_array($wgPartialMessageCache)) {
 141                                 $conditions['page_title']=$wgPartialMessageCache;
 142                         } else {
 143                                 require_once("MessageCacheHints.php");
 144                                 $conditions['page_title']=MessageCacheHints::get();
 145                         }
 146                 }
 147                 $res = $dbr->select( array( 'page', 'text' ),
 148                         array( 'page_title', 'old_text', 'old_flags' ),
 149                         'page_is_redirect=0 AND page_namespace = '.NS_MEDIAWIKI.' AND page_latest = old_id',
 150                         $fname
 151                 );
 152
 153                 $this->mCache = array();
 154                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 155                         $this->mCache[$row->page_title] = Revision::getRevisionText( $row );
 156                 }
 157
 158                 $dbr->freeResult( $res );
 159         }
 160
 161         /**
 162          * Not really needed anymore
 163          */
 164         function getKeys() {
 165                 global $wgAllMessagesEn, $wgContLang;
 166                 if ( !$this->mKeys ) {
 167                         $this->mKeys = array();
 168                         foreach ( $wgAllMessagesEn as $key => $value ) {
 169                                 $title = $wgContLang->ucfirst( $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, $isfullkey = false ) {
 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                         $title = $lang->ucfirst( $key );
 242                         if(!$isfullkey && ($langcode != $wgContLanguageCode) ) {
 243                                 $title .= '/' . $langcode;
 244                         }
 245                         $message = $this->getFromCache( $title );
 246                 }
 247                 # Try the extension array
 248                 if( !$message ) {
 249                         $message = @$this->mExtensionMessages[$key];
 250                 }
 251
 252                 # Try the array in the language object
 253                 if( !$message ) {
 254                         wfSuppressWarnings();
 255                         $message = $lang->getMessage( $key );
 256                         wfRestoreWarnings();
 257                 }
 258
 259                 # Try the English array
 260                 if( !$message && $langcode != 'en' ) {
 261                         wfSuppressWarnings();
 262                         $message = Language::getMessage( $key );
 263                         wfRestoreWarnings();
 264                 }
 265
 266                 # Is this a custom message? Try the default language in the db...
 267                 if( !$message &&
 268                         !$this->mDisable && $useDB &&
 269                         !$isfullkey && ($langcode != $wgContLanguageCode) ) {
 270                         $message = $this->getFromCache( $lang->ucfirst( $key ) );
 271                 }
 272
 273                 # Final fallback
 274                 if( !$message ) {
 275                         $message = "&lt;$key&gt;";
 276                 }
 277
 278                 # Replace brace tags
 279                 $message = $this->transform( $message );
 280                 return $message;
 281         }
 282
 283         function getFromCache( $title ) {
 284                 $message = false;
 285
 286                 # Try the cache
 287                 if( $this->mUseCache && is_array( $this->mCache ) && array_key_exists( $title, $this->mCache ) ) {
 288                         $message = $this->mCache[$title];
 289                 }
 290
 291                 if ( !$message && $this->mUseCache ) {
 292                         $message = $this->mMemc->get( $this->mMemcKey . ':' . $title );
 293                         if( $message ) {
 294                                 $this->mCache[$title] = $message;
 295                         }
 296                 }
 297
 298                 # If it wasn't in the cache, load each message from the DB individually
 299                 if ( !$message ) {
 300                         $dbr =& wfGetDB( DB_SLAVE );
 301                         $result = $dbr->selectRow( array( 'page', 'text' ),
 302                           array( 'old_flags', 'old_text' ),
 303                           'page_namespace=' . NS_MEDIAWIKI .
 304                           ' AND page_title=' . $dbr->addQuotes( $title ) .
 305                           ' AND page_latest=old_id',
 306                           'MessageCache::get' );
 307                         if ( $result ) {
 308                                 $message = Revision::getRevisionText( $result );
 309                                 if ($this->mUseCache) {
 310                                         $this->mCache[$title]=$message;
 311                                         /* individual messages may be often
 312                                            recached until proper purge code exists
 313                                         */
 314                                         $this->mMemc->set( $this->mMemcKey . ':' . $title, $message, 300 );
 315                                 }
 316                         }
 317                 }
 318
 319                 return $message;
 320         }
 321
 322         function transform( $message ) {
 323                 if( !$this->mDisableTransform ) {
 324                         if( strpos( $message, '{{' ) !== false ) {
 325                                 $message = $this->mParser->transformMsg( $message, $this->mParserOptions );
 326                         }
 327                 }
 328                 return $message;
 329         }
 330
 331         function disable() { $this->mDisable = true; }
 332         function enable() { $this->mDisable = false; }
 333         function disableTransform() { $this->mDisableTransform = true; }
 334         function enableTransform() { $this->mDisableTransform = false; }
 335
 336         function addMessage( $key, $value ) {
 337                 $this->mExtensionMessages[$key] = $value;
 338         }
 339
 340         function addMessages( $messages ) {
 341                 foreach ( $messages as $key => $value ) {
 342                         $this->mExtensionMessages[$key] = $value;
 343                 }
 344         }
 345
 346         /**
 347          * Clear all stored messages. Mainly used after a mass rebuild.
 348          */
 349         function clear() {
 350                 if( $this->mUseCache ) {
 351                         $this->mMemc->delete( $this->mMemcKey );
 352                 }
 353         }
 354 }
 355 ?>