includes/MessageCache.php

   1 <?php
   2
   3 # Message cache
   4 # Performs various useful MediaWiki namespace-related functions
   5
   6 define( 'MSG_LOAD_TIMEOUT', 60);
   7 define( 'MSG_LOCK_TIMEOUT', 10);
   8 define( 'MSG_WAIT_TIMEOUT', 10);
   9
  10 class MessageCache
  11 {
  12         var $mCache, $mUseCache, $mDisable, $mExpiry;
  13         var $mMemcKey, $mKeys, $mParserOptions, $mParser;
  14         var $mExtensionMessages;
  15
  16         var $mInitialised = false;
  17
  18         function initialise( &$memCached, $useDB, $expiry, $memcPrefix ) {
  19                 $fname = 'MessageCache::initialise';
  20                 wfProfileIn( $fname );
  21                 $this->mUseCache = !is_null( $memCached );
  22                 $this->mMemc = &$memCached;
  23                 $this->mDisable = !$useDB;
  24                 $this->mExpiry = $expiry;
  25                 $this->mDisableTransform = false;
  26                 $this->mMemcKey = $memcPrefix.':messages';
  27                 $this->mKeys = false; # initialised on demand
  28                 $this->mInitialised = true;
  29                 wfProfileIn( $fname.'-parseropt' );
  30                 $this->mParserOptions = ParserOptions::newFromUser( $u=NULL );
  31                 wfProfileOut( $fname.'-parseropt' );
  32                 wfProfileIn( $fname.'-parser' );
  33                 $this->mParser = new Parser;
  34                 wfProfileOut( $fname.'-parser' );
  35
  36                 $this->load();
  37                 wfProfileOut( $fname );
  38         }
  39
  40         # Loads messages either from memcached or the database, if not disabled
  41         # On error, quietly switches to a fallback mode
  42         # Returns false for a reportable error, true otherwise
  43         function load() {
  44                 global $wgAllMessagesEn;
  45
  46                 if ( $this->mDisable ) {
  47                         wfDebug( "MessageCache::load(): disabled\n" );
  48                         return true;
  49                 }
  50                 $fname = 'MessageCache::load';
  51                 wfProfileIn( $fname );
  52                 $success = true;
  53
  54                 if ( $this->mUseCache ) {
  55                         wfProfileIn( $fname.'-fromcache' );
  56                         $this->mCache = $this->mMemc->get( $this->mMemcKey );
  57                         wfProfileOut( $fname.'-fromcache' );
  58
  59                         # If there's nothing in memcached, load all the messages from the database
  60                         if ( !$this->mCache ) {
  61                                 wfDebug( "MessageCache::load(): loading all messages\n" );
  62                                 $this->lock();
  63                                 # Other threads don't need to load the messages if another thread is doing it.
  64                                 $success = $this->mMemc->set( $this->mMemcKey, "loading", MSG_LOAD_TIMEOUT );
  65                                 if ( $success ) {
  66                                         wfProfileIn( $fname.'-load' );
  67                                         $this->loadFromDB();
  68                                         wfProfileOut( $fname.'-load' );
  69                                         # Save in memcached
  70                                         # Keep trying if it fails, this is kind of important
  71                                         wfProfileIn( $fname.'-save' );
  72                                         for ( $i=0; $i<20 && !$this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry ); $i++ ) {
  73                                                 usleep(mt_rand(500000,1500000));
  74                                         }
  75                                         wfProfileOut( $fname.'-save' );
  76                                         if ( $i == 20 ) {
  77                                                 $this->mMemc->set( $this->mMemcKey, 'error', 86400 );
  78                                                 wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
  79                                         }
  80                                 }
  81                                 $this->unlock();
  82                         }
  83
  84                         if ( !is_array( $this->mCache ) ) {
  85                                 wfMsg( "MessageCache::load(): individual message mode\n" );
  86                                 # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
  87                                 # Causing too much DB load, disabling -- TS
  88                                 $this->mDisable = true;
  89                                 /*
  90                                 if ( $this->mCache == "loading" ) {
  91                                         $this->mUseCache = false;
  92                                 } elseif ( $this->mCache == "error" ) {
  93                                         $this->mUseCache = false;
  94                                         $success = false;
  95                                 } else {
  96                                         $this->mDisable = true;
  97                                         $success = false;
  98                                 }*/
  99                                 $this->mCache = false;
 100                         }
 101                 }
 102                 wfProfileOut( $fname );
 103                 return $success;
 104         }
 105
 106         # Loads all cacheable messages from the database
 107         function loadFromDB()
 108         {
 109                 $fname = 'MessageCache::loadFromDB';
 110                 $dbr =& wfGetDB( DB_SLAVE );
 111                 $res = $dbr->select( 'cur',
 112                         array( 'cur_title', 'cur_text' ),
 113                         array( 'cur_is_redirect' => 0, 'cur_namespace' => NS_MEDIAWIKI ),
 114                         $fname
 115                 );
 116
 117                 $this->mCache = array();
 118                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 119                         $this->mCache[$row->cur_title] = $row->cur_text;
 120                 }
 121
 122                 $dbr->freeResult( $res );
 123         }
 124
 125         # Not really needed anymore
 126         function getKeys() {
 127                 global $wgAllMessagesEn, $wgLang;
 128                 if ( !$this->mKeys ) {
 129                         $this->mKeys = array();
 130                         foreach ( $wgAllMessagesEn as $key => $value ) {
 131                                 array_push( $this->mKeys, $wgLang->ucfirst( $key ) );
 132                         }
 133                 }
 134                 return $this->mKeys;
 135         }
 136
 137         # Obsolete
 138         function isCacheable( $key ) {
 139                 return true;
 140                 /*
 141                 global $wgAllMessagesEn, $wgLang;
 142                 return array_key_exists( $wgLang->lcfirst( $key ), $wgAllMessagesEn ) ||
 143                         array_key_exists( $key, $wgAllMessagesEn );
 144                 */
 145         }
 146
 147         function replace( $title, $text ) {
 148                 $this->lock();
 149                 $this->load();
 150                 if ( is_array( $this->mCache ) ) {
 151                         $this->mCache[$title] = $text;
 152                         $this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 153                 }
 154                 $this->unlock();
 155         }
 156
 157         # Returns success
 158         # Represents a write lock on the messages key
 159         function lock() {
 160                 if ( !$this->mUseCache ) {
 161                         return true;
 162                 }
 163
 164                 $lockKey = $this->mMemcKey . 'lock';
 165                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 166                         sleep(1);
 167                 }
 168
 169                 return $i >= MSG_WAIT_TIMEOUT;
 170         }
 171
 172         function unlock() {
 173                 if ( !$this->mUseCache ) {
 174                         return;
 175                 }
 176
 177                 $lockKey = $this->mMemcKey . 'lock';
 178                 $this->mMemc->delete( $lockKey );
 179         }
 180
 181         function get( $key, $useDB ) {
 182                 global $wgLang, $wgLanguageCode;
 183
 184                 # If uninitialised, someone is trying to call this halfway through Setup.php
 185                 if ( !$this->mInitialised ) {
 186                         return "&lt;$key&gt;";
 187                 }
 188
 189                 $message = false;
 190                 if ( !$this->mDisable ) {
 191                         $title = $wgLang->ucfirst( $key );
 192
 193
 194                         # Try the cache
 195                         if ( $this->mUseCache && $this->mCache && array_key_exists( $title, $this->mCache ) ) {
 196                                 $message = $this->mCache[$title];
 197                         }
 198
 199                         # If it wasn't in the cache, load each message from the DB individually
 200                         if ( !$message && $useDB) {
 201                                 $dbr =& wfGetDB( DB_SLAVE );
 202                                 $result = $dbr->getArray( 'cur', array('cur_text'),
 203                                   array( 'cur_namespace' => NS_MEDIAWIKI, 'cur_title' => $title ),
 204                                   'MessageCache::get' );
 205                                 if ( $result ) {
 206                                         $message = $result->cur_text;
 207                                 }
 208                         }
 209                 }
 210                 # Try the extension array
 211                 if ( !$message ) {
 212                         $message = @$this->mExtensionMessages[$key];
 213                 }
 214
 215                 # Try the array in $wgLang
 216                 if ( !$message ) {
 217                         $message = $wgLang->getMessage( $key );
 218                 }
 219
 220                 # Try the English array
 221                 if ( !$message && $wgLanguageCode != 'en' ) {
 222                         $message = Language::getMessage( $key );
 223                 }
 224
 225                 # Final fallback
 226                 if ( !$message ) {
 227                         $message = "&lt;$key&gt;";
 228                 }
 229
 230                 # Replace brace tags
 231                 $message = $this->transform( $message );
 232                 return $message;
 233         }
 234
 235         function transform( $message ) {
 236                 if( !$this->mDisableTransform ) {
 237                         if ( strstr( $message, '{{' ) !== false ) {
 238                                 $message = $this->mParser->transformMsg( $message, $this->mParserOptions );
 239                         }
 240                 }
 241                 return $message;
 242         }
 243
 244         function disable() { $this->mDisable = true; }
 245         function enable() { $this->mDisable = false; }
 246         function disableTransform() { $this->mDisableTransform = true; }
 247
 248         function addMessage( $key, $value ) {
 249                 $this->mExtensionMessages[$key] = $value;
 250         }
 251
 252         function addMessages( $messages ) {
 253                 foreach ( $messages as $key => $value ) {
 254                         $this->mExtensionMessages[$key] = $value;
 255                 }
 256         }
 257
 258         # Clear all stored messages. Mainly used after a mass rebuild.
 259         function clear() {
 260                 if( $this->mUseCache ) {
 261                         $this->mMemc->delete( $this->mMemcKey );
 262                 }
 263         }
 264 }
 265 ?>