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
  15         var $mInitialised = false;
  16
  17         function initialise( $useMemCached, $useDB, $expiry, $memcPrefix ) {
  18                 $this->mUseCache = $useMemCached;
  19                 $this->mDisable = !$useDB;
  20                 $this->mExpiry = $expiry;
  21                 $this->mDisableTransform = false;
  22                 $this->mMemcKey = "$memcPrefix:messages";
  23                 $this->mKeys = false; # initialised on demand
  24                 $this->mInitialised = true;
  25                 $this->mParserOptions = ParserOptions::newFromUser( $u=NULL );
  26                 $this->mParser = new Parser;
  27
  28                 $this->load();
  29         }
  30
  31         # Loads messages either from memcached or the database, if not disabled
  32         # On error, quietly switches to a fallback mode
  33         # Returns false for a reportable error, true otherwise
  34         function load() {
  35                 global $wgAllMessagesEn, $wgMemc;
  36
  37                 if ( $this->mDisable ) {
  38                         return true;
  39                 }
  40
  41                 $success = true;
  42
  43                 if ( $this->mUseCache ) {
  44                         $this->mCache = $wgMemc->get( $this->mMemcKey );
  45
  46                         # If there's nothing in memcached, load all the messages from the database
  47                         if ( !$this->mCache ) {
  48                                 $this->lock();
  49                                 # Other threads don't need to load the messages if another thread is doing it.
  50                                 $wgMemc->set( $this->mMemcKey, "loading", MSG_LOAD_TIMEOUT );
  51                                 $this->loadFromDB();
  52                                 # Save in memcached
  53                                 if ( !$wgMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry ) ) {
  54                                         # Hack for slabs reassignment problem
  55                                         $wgMemc->set( $this->mMemcKey, "error" );
  56                                         wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
  57                                 }
  58                                 $this->unlock();
  59                         }
  60
  61                         if ( !is_array( $this->mCache ) ) {
  62                                 # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
  63                                 if ( $this->mCache == "loading" ) {
  64                                         $this->mUseCache = false;
  65                                 } elseif ( $this->mCache == "error" ) {
  66                                         $this->mUseCache = false;
  67                                         $success = false;
  68                                 } else {
  69                                         $this->mDisable = true;
  70                                         $success = false;
  71                                 }
  72                                 $this->mCache = false;
  73                         }
  74                 }
  75                 return $success;
  76         }
  77
  78         # Loads all cacheable messages from the database
  79         function loadFromDB()
  80         {
  81                 $fname = "MessageCache::loadFromDB";
  82                 $sql = "SELECT cur_title,cur_text FROM cur WHERE cur_namespace=" . NS_MEDIAWIKI;
  83                 $res = wfQuery( $sql, DB_READ, $fname );
  84
  85                 $this->mCache = array();
  86                 for ( $row = wfFetchObject( $res ); $row; $row = wfFetchObject( $res ) ) {
  87                         $this->mCache[$row->cur_title] = $row->cur_text;
  88                 }
  89
  90                 wfFreeResult( $res );
  91         }
  92
  93         # Not really needed anymore
  94         function getKeys() {
  95                 global $wgAllMessagesEn, $wgLang;
  96                 if ( !$this->mKeys ) {
  97                         $this->mKeys = array();
  98                         foreach ( $wgAllMessagesEn as $key => $value ) {
  99                                 array_push( $this->mKeys, $wgLang->ucfirst( $key ) );
 100                         }
 101                 }
 102                 return $this->mKeys;
 103         }
 104
 105         # Obsolete
 106         function isCacheable( $key ) {
 107                 return true;
 108                 /*
 109                 global $wgAllMessagesEn, $wgLang;
 110                 return array_key_exists( $wgLang->lcfirst( $key ), $wgAllMessagesEn ) ||
 111                         array_key_exists( $key, $wgAllMessagesEn );
 112                 */
 113         }
 114
 115         function replace( $title, $text ) {
 116                 global $wgMemc;
 117                 $this->lock();
 118                 $this->load();
 119                 if ( is_array( $this->mCache ) ) {
 120                         $this->mCache[$title] = $text;
 121                         $wgMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 122                 }
 123                 $this->unlock();
 124         }
 125
 126         # Returns success
 127         # Represents a write lock on the messages key
 128         function lock() {
 129                 global $wgMemc;
 130
 131                 if ( !$this->mUseCache ) {
 132                         return true;
 133                 }
 134
 135                 $lockKey = $this->mMemcKey . "lock";
 136                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$wgMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 137                         sleep(1);
 138                 }
 139
 140                 return $i >= MSG_WAIT_TIMEOUT;
 141         }
 142
 143         function unlock() {
 144                 global $wgMemc;
 145
 146                 if ( !$this->mUseCache ) {
 147                         return;
 148                 }
 149
 150                 $lockKey = $this->mMemcKey . "lock";
 151                 $wgMemc->delete( $lockKey );
 152         }
 153
 154         function get( $key, $useDB ) {
 155                 global $wgLang, $wgLanguageCode;
 156
 157                 # If uninitialised, someone is trying to call this halfway through Setup.php
 158                 if ( !$this->mInitialised ) {
 159                         return "&lt;$key&gt;";
 160                 }
 161
 162                 if ( $this->mDisable ) {
 163                         return $this->transform( $wgLang->getMessage( $key ) );
 164                 }
 165                 $title = $wgLang->ucfirst( $key );
 166
 167                 $message = false;
 168
 169                 # Try the cache
 170                 if ( $this->mUseCache && $this->mCache && array_key_exists( $title, $this->mCache ) ) {
 171                         $message = $this->mCache[$title];
 172                 }
 173
 174                 # If it wasn't in the cache, load each message from the DB individually
 175                 if ( !$message && $useDB) {
 176                         $result = wfGetArray( "cur", array("cur_text"),
 177                           array( "cur_namespace" => NS_MEDIAWIKI, "cur_title" => $title ),
 178                           "MessageCache::get" );
 179                         if ( $result ) {
 180                                 $message = $result->cur_text;
 181                         }
 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 }
 218 ?>