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                                 $title = $wgContLang->ucfirst( $key );
 169                                 array_push( $this->mKeys, $title );
 170                         }
 171                 }
 172                 return $this->mKeys;
 173         }
 174
 175         /**
 176          * Obsolete
 177          */
 178         function isCacheable( $key ) {
 179                 return true;
 180         }
 181
 182         function replace( $title, $text ) {
 183                 $this->lock();
 184                 $this->load();
 185                 if ( is_array( $this->mCache ) ) {
 186                         $this->mCache[$title] = $text;
 187                         $this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 188                 }
 189                 $this->unlock();
 190         }
 191
 192         /**
 193          * Returns success
 194          * Represents a write lock on the messages key
 195          */
 196         function lock() {
 197                 if ( !$this->mUseCache ) {
 198                         return true;
 199                 }
 200
 201                 $lockKey = $this->mMemcKey . 'lock';
 202                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 203                         sleep(1);
 204                 }
 205
 206                 return $i >= MSG_WAIT_TIMEOUT;
 207         }
 208
 209         function unlock() {
 210                 if ( !$this->mUseCache ) {
 211                         return;
 212                 }
 213
 214                 $lockKey = $this->mMemcKey . 'lock';
 215                 $this->mMemc->delete( $lockKey );
 216         }
 217
 218         function get( $key, $useDB, $forcontent=true ) {
 219                 global $wgContLanguageCode;
 220                 if( $forcontent ) {
 221                         global $wgContLang;
 222                         $lang =& $wgContLang;
 223                         $langcode = $wgContLanguageCode;
 224                 } else {
 225                         global $wgLang, $wgLanguageCode;
 226                         $lang =& $wgLang;
 227                         $langcode = $wgLanguageCode;
 228                 }
 229                 # If uninitialised, someone is trying to call this halfway through Setup.php
 230                 if( !$this->mInitialised ) {
 231                         return "&lt;$key&gt;";
 232                 }
 233                 # If cache initialization was deferred, start it now.
 234                 if( $this->mDeferred ) {
 235                         $this->load();
 236                 }
 237
 238                 $message = false;
 239                 if( !$this->mDisable && $useDB ) {
 240                         $title = $lang->ucfirst( $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 = Revision::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 ?>