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