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