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