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                                 $success = $this->mMemc->set( $this->mMemcKey, "loading", MSG_LOAD_TIMEOUT );
  55                                 if ( $success ) {
  56                                         $this->loadFromDB();
  57                                         # Save in memcached
  58                                         # Keep trying if it fails, this is kind of important
  59                                         for ( $i=0; $i<20 && !$this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry ); $i++ ) {
  60                                                 usleep(mt_rand(500000,1500000));
  61                                         }
  62                                         if ( $i == 20 ) {
  63                                                 $this->mMemc->set( $this->mMemcKey, "error", 86400 );
  64                                                 wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
  65                                         }
  66                                 }
  67                                 $this->unlock();
  68                         }
  69
  70                         if ( !is_array( $this->mCache ) ) {
  71                                 wfMsg( "MessageCache::load(): individual message mode\n" );
  72                                 # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
  73                                 # Causing too much DB load, disabling -- TS
  74                                 $this->mDisable = true;
  75                                 /*
  76                                 if ( $this->mCache == "loading" ) {
  77                                         $this->mUseCache = false;
  78                                 } elseif ( $this->mCache == "error" ) {
  79                                         $this->mUseCache = false;
  80                                         $success = false;
  81                                 } else {
  82                                         $this->mDisable = true;
  83                                         $success = false;
  84                                 }*/
  85                                 $this->mCache = false;
  86                         }
  87                 }
  88                 return $success;
  89         }
  90
  91         # Loads all cacheable messages from the database
  92         function loadFromDB()
  93         {
  94                 $fname = "MessageCache::loadFromDB";
  95                 $dbr =& wfGetDB( DB_SLAVE );
  96                 $res = $dbr->select( 'cur',
  97                         array( 'cur_title', 'cur_text' ),
  98                         array( 'cur_is_redirect' => 0, 'cur_namespace' => NS_MEDIAWIKI ),
  99                         $fname
 100                 );
 101
 102                 $this->mCache = array();
 103                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 104                         $this->mCache[$row->cur_title] = $row->cur_text;
 105                 }
 106
 107                 $dbr->freeResult( $res );
 108         }
 109
 110         # Not really needed anymore
 111         function getKeys() {
 112                 global $wgAllMessagesEn, $wgLang;
 113                 if ( !$this->mKeys ) {
 114                         $this->mKeys = array();
 115                         foreach ( $wgAllMessagesEn as $key => $value ) {
 116                                 array_push( $this->mKeys, $wgLang->ucfirst( $key ) );
 117                         }
 118                 }
 119                 return $this->mKeys;
 120         }
 121
 122         # Obsolete
 123         function isCacheable( $key ) {
 124                 return true;
 125                 /*
 126                 global $wgAllMessagesEn, $wgLang;
 127                 return array_key_exists( $wgLang->lcfirst( $key ), $wgAllMessagesEn ) ||
 128                         array_key_exists( $key, $wgAllMessagesEn );
 129                 */
 130         }
 131
 132         function replace( $title, $text ) {
 133                 $this->lock();
 134                 $this->load();
 135                 if ( is_array( $this->mCache ) ) {
 136                         $this->mCache[$title] = $text;
 137                         $this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 138                 }
 139                 $this->unlock();
 140         }
 141
 142         # Returns success
 143         # Represents a write lock on the messages key
 144         function lock() {
 145                 if ( !$this->mUseCache ) {
 146                         return true;
 147                 }
 148
 149                 $lockKey = $this->mMemcKey . "lock";
 150                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 151                         sleep(1);
 152                 }
 153
 154                 return $i >= MSG_WAIT_TIMEOUT;
 155         }
 156
 157         function unlock() {
 158                 if ( !$this->mUseCache ) {
 159                         return;
 160                 }
 161
 162                 $lockKey = $this->mMemcKey . "lock";
 163                 $this->mMemc->delete( $lockKey );
 164         }
 165
 166         function get( $key, $useDB ) {
 167                 global $wgLang, $wgLanguageCode;
 168
 169                 # If uninitialised, someone is trying to call this halfway through Setup.php
 170                 if ( !$this->mInitialised ) {
 171                         return "&lt;$key&gt;";
 172                 }
 173
 174                 $message = false;
 175                 if ( !$this->mDisable ) {
 176                         $title = $wgLang->ucfirst( $key );
 177
 178
 179                         # Try the cache
 180                         if ( $this->mUseCache && $this->mCache && array_key_exists( $title, $this->mCache ) ) {
 181                                 $message = $this->mCache[$title];
 182                         }
 183
 184                         # If it wasn't in the cache, load each message from the DB individually
 185                         if ( !$message && $useDB) {
 186                                 $dbr =& wfGetDB( DB_SLAVE );
 187                                 $result = $dbr->getArray( "cur", array("cur_text"),
 188                                   array( "cur_namespace" => NS_MEDIAWIKI, "cur_title" => $title ),
 189                                   "MessageCache::get" );
 190                                 if ( $result ) {
 191                                         $message = $result->cur_text;
 192                                 }
 193                         }
 194                 }
 195                 # Try the extension array
 196                 if ( !$message ) {
 197                         $message = @$this->mExtensionMessages[$key];
 198                 }
 199
 200                 # Try the array in $wgLang
 201                 if ( !$message ) {
 202                         $message = $wgLang->getMessage( $key );
 203                 }
 204
 205                 # Try the English array
 206                 if ( !$message && $wgLanguageCode != "en" ) {
 207                         $message = Language::getMessage( $key );
 208                 }
 209
 210                 # Final fallback
 211                 if ( !$message ) {
 212                         $message = "&lt;$key&gt;";
 213                 }
 214
 215                 # Replace brace tags
 216                 $message = $this->transform( $message );
 217                 return $message;
 218         }
 219
 220         function transform( $message ) {
 221                 if( !$this->mDisableTransform ) {
 222                         if ( strstr( $message, "{{" ) !== false ) {
 223                                 $message = $this->mParser->transformMsg( $message, $this->mParserOptions );
 224                         }
 225                 }
 226                 return $message;
 227         }
 228
 229         function disable() { $this->mDisable = true; }
 230         function enable() { $this->mDisable = false; }
 231         function disableTransform() { $this->mDisableTransform = true; }
 232
 233         function addMessage( $key, $value ) {
 234                 $this->mExtensionMessages[$key] = $value;
 235         }
 236
 237         function addMessages( $messages ) {
 238                 foreach ( $messages as $key => $value ) {
 239                         $this->mExtensionMessages[$key] = $value;
 240                 }
 241         }
 242 }
 243 ?>