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
  26         var $mInitialised = false;
  27
  28         function initialise( &$memCached, $useDB, $expiry, $memcPrefix ) {
  29                 $fname = 'MessageCache::initialise';
  30                 wfProfileIn( $fname );
  31                 $this->mUseCache = !is_null( $memCached );
  32                 $this->mMemc = &$memCached;
  33                 $this->mDisable = !$useDB;
  34                 $this->mExpiry = $expiry;
  35                 $this->mDisableTransform = false;
  36                 $this->mMemcKey = $memcPrefix.':messages';
  37                 $this->mKeys = false; # initialised on demand
  38                 $this->mInitialised = true;
  39                 wfProfileIn( $fname.'-parseropt' );
  40                 $this->mParserOptions = ParserOptions::newFromUser( $u=NULL );
  41                 wfProfileOut( $fname.'-parseropt' );
  42                 wfProfileIn( $fname.'-parser' );
  43                 $this->mParser = new Parser;
  44                 wfProfileOut( $fname.'-parser' );
  45
  46                 $this->load();
  47                 wfProfileOut( $fname );
  48         }
  49
  50         /**
  51          * Loads messages either from memcached or the database, if not disabled
  52          * On error, quietly switches to a fallback mode
  53          * Returns false for a reportable error, true otherwise
  54          */
  55         function load() {
  56                 global $wgAllMessagesEn;
  57
  58                 if ( $this->mDisable ) {
  59                         wfDebug( "MessageCache::load(): disabled\n" );
  60                         return true;
  61                 }
  62                 $fname = 'MessageCache::load';
  63                 wfProfileIn( $fname );
  64                 $success = true;
  65
  66                 if ( $this->mUseCache ) {
  67                         wfProfileIn( $fname.'-fromcache' );
  68                         $this->mCache = $this->mMemc->get( $this->mMemcKey );
  69                         wfProfileOut( $fname.'-fromcache' );
  70
  71                         # If there's nothing in memcached, load all the messages from the database
  72                         if ( !$this->mCache ) {
  73                                 wfDebug( "MessageCache::load(): loading all messages\n" );
  74                                 $this->lock();
  75                                 # Other threads don't need to load the messages if another thread is doing it.
  76                                 $success = $this->mMemc->set( $this->mMemcKey, "loading", MSG_LOAD_TIMEOUT );
  77                                 if ( $success ) {
  78                                         wfProfileIn( $fname.'-load' );
  79                                         $this->loadFromDB();
  80                                         wfProfileOut( $fname.'-load' );
  81                                         # Save in memcached
  82                                         # Keep trying if it fails, this is kind of important
  83                                         wfProfileIn( $fname.'-save' );
  84                                         for ( $i=0; $i<20 && !$this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry ); $i++ ) {
  85                                                 usleep(mt_rand(500000,1500000));
  86                                         }
  87                                         wfProfileOut( $fname.'-save' );
  88                                         if ( $i == 20 ) {
  89                                                 $this->mMemc->set( $this->mMemcKey, 'error', 86400 );
  90                                                 wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
  91                                         }
  92                                 }
  93                                 $this->unlock();
  94                         }
  95
  96                         if ( !is_array( $this->mCache ) ) {
  97                                 wfMsg( "MessageCache::load(): individual message mode\n" );
  98                                 # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
  99                                 # Causing too much DB load, disabling -- TS
 100                                 $this->mDisable = true;
 101                                 /*
 102                                 if ( $this->mCache == "loading" ) {
 103                                         $this->mUseCache = false;
 104                                 } elseif ( $this->mCache == "error" ) {
 105                                         $this->mUseCache = false;
 106                                         $success = false;
 107                                 } else {
 108                                         $this->mDisable = true;
 109                                         $success = false;
 110                                 }*/
 111                                 $this->mCache = false;
 112                         }
 113                 }
 114                 wfProfileOut( $fname );
 115                 return $success;
 116         }
 117
 118         /**
 119          * Loads all cacheable messages from the database
 120          */
 121         function loadFromDB() {
 122                         $fname = 'MessageCache::loadFromDB';
 123                 $dbr =& wfGetDB( DB_SLAVE );
 124                 $res = $dbr->select( 'cur',
 125                         array( 'cur_title', 'cur_text' ),
 126                         array( 'cur_is_redirect' => 0, 'cur_namespace' => NS_MEDIAWIKI ),
 127                         $fname
 128                 );
 129
 130                 $this->mCache = array();
 131                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 132                         $this->mCache[$row->cur_title] = $row->cur_text;
 133                 }
 134
 135                 $dbr->freeResult( $res );
 136         }
 137
 138         /**
 139          * Not really needed anymore
 140          */
 141         function getKeys() {
 142                 global $wgAllMessagesEn, $wgLang;
 143                 if ( !$this->mKeys ) {
 144                         $this->mKeys = array();
 145                         foreach ( $wgAllMessagesEn as $key => $value ) {
 146                                 array_push( $this->mKeys, $wgLang->ucfirst( $key ) );
 147                         }
 148                 }
 149                 return $this->mKeys;
 150         }
 151
 152         /**
 153          * Obsolete
 154          */
 155         function isCacheable( $key ) {
 156                 return true;
 157                 /*
 158                 global $wgAllMessagesEn, $wgLang;
 159                 return array_key_exists( $wgLang->lcfirst( $key ), $wgAllMessagesEn ) ||
 160                         array_key_exists( $key, $wgAllMessagesEn );
 161                 */
 162         }
 163
 164         function replace( $title, $text ) {
 165                 $this->lock();
 166                 $this->load();
 167                 if ( is_array( $this->mCache ) ) {
 168                         $this->mCache[$title] = $text;
 169                         $this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 170                 }
 171                 $this->unlock();
 172         }
 173
 174         /**
 175          * Returns success
 176          * Represents a write lock on the messages key
 177          */
 178         function lock() {
 179                 if ( !$this->mUseCache ) {
 180                         return true;
 181                 }
 182
 183                 $lockKey = $this->mMemcKey . 'lock';
 184                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 185                         sleep(1);
 186                 }
 187
 188                 return $i >= MSG_WAIT_TIMEOUT;
 189         }
 190
 191         function unlock() {
 192                 if ( !$this->mUseCache ) {
 193                         return;
 194                 }
 195
 196                 $lockKey = $this->mMemcKey . 'lock';
 197                 $this->mMemc->delete( $lockKey );
 198         }
 199
 200         function get( $key, $useDB ) {
 201                 global $wgLang, $wgLanguageCode;
 202
 203                 # If uninitialised, someone is trying to call this halfway through Setup.php
 204                 if ( !$this->mInitialised ) {
 205                         return "&lt;$key&gt;";
 206                 }
 207
 208                 $message = false;
 209                 if ( !$this->mDisable && $useDB ) {
 210                         $title = $wgLang->ucfirst( $key );
 211
 212
 213                         # Try the cache
 214                         if ( $this->mUseCache && $this->mCache && array_key_exists( $title, $this->mCache ) ) {
 215                                 $message = $this->mCache[$title];
 216                         }
 217
 218                         # If it wasn't in the cache, load each message from the DB individually
 219                         if ( !$message ) {
 220                                 $dbr =& wfGetDB( DB_SLAVE );
 221                                 $result = $dbr->getArray( 'cur', array('cur_text'),
 222                                   array( 'cur_namespace' => NS_MEDIAWIKI, 'cur_title' => $title ),
 223                                   'MessageCache::get' );
 224                                 if ( $result ) {
 225                                         $message = $result->cur_text;
 226                                 }
 227                         }
 228                 }
 229                 # Try the extension array
 230                 if ( !$message ) {
 231                         $message = @$this->mExtensionMessages[$key];
 232                 }
 233
 234                 # Try the array in $wgLang
 235                 if ( !$message ) {
 236                         wfSuppressWarnings();
 237                         $message = $wgLang->getMessage( $key );
 238                         wfRestoreWarnings();
 239                 }
 240
 241                 # Try the English array
 242                 if ( !$message && $wgLanguageCode != 'en' ) {
 243                         wfSuppressWarnings();
 244                         $message = Language::getMessage( $key );
 245                         wfRestoreWarnings();
 246                 }
 247
 248                 # Final fallback
 249                 if ( !$message ) {
 250                         $message = "&lt;$key&gt;";
 251                 }
 252
 253                 # Replace brace tags
 254                 $message = $this->transform( $message );
 255                 return $message;
 256         }
 257
 258         function transform( $message ) {
 259                 if( !$this->mDisableTransform ) {
 260                         if ( strstr( $message, '{{' ) !== false ) {
 261                                 $message = $this->mParser->transformMsg( $message, $this->mParserOptions );
 262                         }
 263                 }
 264                 return $message;
 265         }
 266
 267         function disable() { $this->mDisable = true; }
 268         function enable() { $this->mDisable = false; }
 269         function disableTransform() { $this->mDisableTransform = true; }
 270         function enableTransform() { $this->mDisableTransform = false; }
 271
 272         function addMessage( $key, $value ) {
 273                 $this->mExtensionMessages[$key] = $value;
 274         }
 275
 276         function addMessages( $messages ) {
 277                 foreach ( $messages as $key => $value ) {
 278                         $this->mExtensionMessages[$key] = $value;
 279                 }
 280         }
 281
 282         /**
 283          * Clear all stored messages. Mainly used after a mass rebuild.
 284          */
 285         function clear() {
 286                 if( $this->mUseCache ) {
 287                         $this->mMemc->delete( $this->mMemcKey );
 288                 }
 289         }
 290 }
 291 ?>