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 $mInitialised = false;
  16
  17         function initialise( &$memCached, $useDB, $expiry, $memcPrefix ) {
  18                 $this->mUseCache = !is_null( $memCached );
  19                 $this->mMemc = &$memCached;
  20                 $this->mDisable = !$useDB;
  21                 $this->mExpiry = $expiry;
  22                 $this->mDisableTransform = false;
  23                 $this->mMemcKey = "$memcPrefix:messages";
  24                 $this->mKeys = false; # initialised on demand
  25                 $this->mInitialised = true;
  26                 $this->mParserOptions = ParserOptions::newFromUser( $u=NULL );
  27                 $this->mParser = new Parser;
  28
  29                 $this->load();
  30         }
  31
  32         # Loads messages either from memcached or the database, if not disabled
  33         # On error, quietly switches to a fallback mode
  34         # Returns false for a reportable error, true otherwise
  35         function load() {
  36                 global $wgAllMessagesEn;
  37
  38                 if ( $this->mDisable ) {
  39                         return true;
  40                 }
  41
  42                 $success = true;
  43
  44                 if ( $this->mUseCache ) {
  45                         $this->mCache = $this->mMemc->get( $this->mMemcKey );
  46
  47                         # If there's nothing in memcached, load all the messages from the database
  48                         if ( !$this->mCache ) {
  49                                 $this->lock();
  50                                 # Other threads don't need to load the messages if another thread is doing it.
  51                                 $this->mMemc->set( $this->mMemcKey, "loading", MSG_LOAD_TIMEOUT );
  52                                 $this->loadFromDB();
  53                                 # Save in memcached
  54                                 if ( !$this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry ) ) {
  55                                         # Hack for slabs reassignment problem
  56                                         $this->mMemc->set( $this->mMemcKey, "error" );
  57                                         wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
  58                                 }
  59                                 $this->unlock();
  60                         }
  61
  62                         if ( !is_array( $this->mCache ) ) {
  63                                 # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
  64                                 if ( $this->mCache == "loading" ) {
  65                                         $this->mUseCache = false;
  66                                 } elseif ( $this->mCache == "error" ) {
  67                                         $this->mUseCache = false;
  68                                         $success = false;
  69                                 } else {
  70                                         $this->mDisable = true;
  71                                         $success = false;
  72                                 }
  73                                 $this->mCache = false;
  74                         }
  75                 }
  76                 return $success;
  77         }
  78
  79         # Loads all cacheable messages from the database
  80         function loadFromDB()
  81         {
  82                 $fname = "MessageCache::loadFromDB";
  83                 $sql = "SELECT cur_title,cur_text FROM cur WHERE cur_namespace=" . NS_MEDIAWIKI;
  84                 $res = wfQuery( $sql, DB_READ, $fname );
  85
  86                 $this->mCache = array();
  87                 for ( $row = wfFetchObject( $res ); $row; $row = wfFetchObject( $res ) ) {
  88                         $this->mCache[$row->cur_title] = $row->cur_text;
  89                 }
  90
  91                 wfFreeResult( $res );
  92         }
  93
  94         # Not really needed anymore
  95         function getKeys() {
  96                 global $wgAllMessagesEn, $wgLang;
  97                 if ( !$this->mKeys ) {
  98                         $this->mKeys = array();
  99                         foreach ( $wgAllMessagesEn as $key => $value ) {
 100                                 array_push( $this->mKeys, $wgLang->ucfirst( $key ) );
 101                         }
 102                 }
 103                 return $this->mKeys;
 104         }
 105
 106         # Obsolete
 107         function isCacheable( $key ) {
 108                 return true;
 109                 /*
 110                 global $wgAllMessagesEn, $wgLang;
 111                 return array_key_exists( $wgLang->lcfirst( $key ), $wgAllMessagesEn ) ||
 112                         array_key_exists( $key, $wgAllMessagesEn );
 113                 */
 114         }
 115
 116         function replace( $title, $text ) {
 117                 $this->lock();
 118                 $this->load();
 119                 if ( is_array( $this->mCache ) ) {
 120                         $this->mCache[$title] = $text;
 121                         $this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 122                 }
 123                 $this->unlock();
 124         }
 125
 126         # Returns success
 127         # Represents a write lock on the messages key
 128         function lock() {
 129                 if ( !$this->mUseCache ) {
 130                         return true;
 131                 }
 132
 133                 $lockKey = $this->mMemcKey . "lock";
 134                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 135                         sleep(1);
 136                 }
 137
 138                 return $i >= MSG_WAIT_TIMEOUT;
 139         }
 140
 141         function unlock() {
 142                 if ( !$this->mUseCache ) {
 143                         return;
 144                 }
 145
 146                 $lockKey = $this->mMemcKey . "lock";
 147                 $this->mMemc->delete( $lockKey );
 148         }
 149
 150         function get( $key, $useDB ) {
 151                 global $wgLang, $wgLanguageCode;
 152
 153                 # If uninitialised, someone is trying to call this halfway through Setup.php
 154                 if ( !$this->mInitialised ) {
 155                         return "&lt;$key&gt;";
 156                 }
 157
 158                 if ( $this->mDisable ) {
 159                         return $this->transform( $wgLang->getMessage( $key ) );
 160                 }
 161                 $title = $wgLang->ucfirst( $key );
 162
 163                 $message = false;
 164
 165                 # Try the cache
 166                 if ( $this->mUseCache && $this->mCache && array_key_exists( $title, $this->mCache ) ) {
 167                         $message = $this->mCache[$title];
 168                 }
 169
 170                 # If it wasn't in the cache, load each message from the DB individually
 171                 if ( !$message && $useDB) {
 172                         $result = wfGetArray( "cur", array("cur_text"),
 173                           array( "cur_namespace" => NS_MEDIAWIKI, "cur_title" => $title ),
 174                           "MessageCache::get" );
 175                         if ( $result ) {
 176                                 $message = $result->cur_text;
 177                         }
 178                 }
 179
 180                 # Try the array in $wgLang
 181                 if ( !$message ) {
 182                         $message = $wgLang->getMessage( $key );
 183                 }
 184
 185                 # Try the English array
 186                 if ( !$message && $wgLanguageCode != "en" ) {
 187                         $message = Language::getMessage( $key );
 188                 }
 189
 190                 # Final fallback
 191                 if ( !$message ) {
 192                         $message = "&lt;$key&gt;";
 193                 }
 194
 195                 # Replace brace tags
 196                 $message = $this->transform( $message );
 197                 return $message;
 198         }
 199
 200         function transform( $message ) {
 201                 if( !$this->mDisableTransform ) {
 202                         if ( strstr( $message, "{{" ) !== false ) {
 203                                 $message = $this->mParser->transformMsg( $message, $this->mParserOptions );
 204                         }
 205                 }
 206                 return $message;
 207         }
 208
 209         function disable() { $this->mDisable = true; }
 210         function enable() { $this->mDisable = false; }
 211         function disableTransform() { $this->mDisableTransform = true; }
 212
 213 }
 214 ?>