includes/MessageCache.php

   1 <?php
   2 /**
   3  *
   4  * @package MediaWiki
   5  */
   6
   7 /**
   8  *
   9  */
  10 define( 'MSG_LOAD_TIMEOUT', 60);
  11 define( 'MSG_LOCK_TIMEOUT', 10);
  12 define( 'MSG_WAIT_TIMEOUT', 10);
  13
  14 /**
  15  * Message cache
  16  * Performs various useful MediaWiki namespace-related functions
  17  *
  18  * @package MediaWiki
  19  */
  20 class MessageCache
  21 {
  22         var $mCache, $mUseCache, $mDisable, $mExpiry;
  23         var $mMemcKey, $mKeys, $mParserOptions, $mParser;
  24         var $mExtensionMessages;
  25         var $mInitialised = false;
  26         var $mDeferred = true;
  27
  28         function initialise( &$memCached, $useDB, $expiry, $memcPrefix) {
  29                 $fname = 'MessageCache::initialise';
  30                 wfProfileIn( $fname );
  31
  32                 $this->mUseCache = !is_null( $memCached );
  33                 $this->mMemc = &$memCached;
  34                 $this->mDisable = !$useDB;
  35                 $this->mExpiry = $expiry;
  36                 $this->mDisableTransform = false;
  37                 $this->mMemcKey = $memcPrefix.':messages';
  38                 $this->mKeys = false; # initialised on demand
  39                 $this->mInitialised = true;
  40
  41                 wfProfileIn( $fname.'-parseropt' );
  42                 $this->mParserOptions = ParserOptions::newFromUser( $u=NULL );
  43                 wfProfileOut( $fname.'-parseropt' );
  44                 wfProfileIn( $fname.'-parser' );
  45                 $this->mParser = new Parser;
  46                 wfProfileOut( $fname.'-parser' );
  47
  48                 # When we first get asked for a message,
  49                 # then we'll fill up the cache. If we
  50                 # can return a cache hit, this saves
  51                 # some extra milliseconds
  52                 $this->mDeferred = true;
  53
  54                 wfProfileOut( $fname );
  55         }
  56
  57         /**
  58          * Loads messages either from memcached or the database, if not disabled
  59          * On error, quietly switches to a fallback mode
  60          * Returns false for a reportable error, true otherwise
  61          */
  62         function load() {
  63                 global $wgAllMessagesEn;
  64
  65                 if ( $this->mDisable ) {
  66                         wfDebug( "MessageCache::load(): disabled\n" );
  67                         return true;
  68                 }
  69                 $fname = 'MessageCache::load';
  70                 wfProfileIn( $fname );
  71                 $success = true;
  72
  73                 if ( $this->mUseCache ) {
  74                         wfProfileIn( $fname.'-fromcache' );
  75                         $this->mCache = $this->mMemc->get( $this->mMemcKey );
  76                         wfProfileOut( $fname.'-fromcache' );
  77
  78                         # If there's nothing in memcached, load all the messages from the database
  79                         if ( !$this->mCache ) {
  80                                 wfDebug( "MessageCache::load(): loading all messages\n" );
  81                                 $this->lock();
  82                                 # Other threads don't need to load the messages if another thread is doing it.
  83                                 $success = $this->mMemc->add( $this->mMemcKey, "loading", MSG_LOAD_TIMEOUT );
  84                                 if ( $success ) {
  85                                         wfProfileIn( $fname.'-load' );
  86                                         $this->loadFromDB();
  87                                         wfProfileOut( $fname.'-load' );
  88                                         # Save in memcached
  89                                         # Keep trying if it fails, this is kind of important
  90                                         wfProfileIn( $fname.'-save' );
  91                                         for ( $i=0; $i<20 && !$this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry ); $i++ ) {
  92                                                 usleep(mt_rand(500000,1500000));
  93                                         }
  94                                         wfProfileOut( $fname.'-save' );
  95                                         if ( $i == 20 ) {
  96                                                 $this->mMemc->set( $this->mMemcKey, 'error', 86400 );
  97                                                 wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
  98                                         }
  99                                 }
 100                                 $this->unlock();
 101                         }
 102
 103                         if ( !is_array( $this->mCache ) ) {
 104                                 wfMsg( "MessageCache::load(): individual message mode\n" );
 105                                 # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
 106                                 # Causing too much DB load, disabling -- TS
 107                                 $this->mDisable = true;
 108                                 /*
 109                                 if ( $this->mCache == "loading" ) {
 110                                         $this->mUseCache = false;
 111                                 } elseif ( $this->mCache == "error" ) {
 112                                         $this->mUseCache = false;
 113                                         $success = false;
 114                                 } else {
 115                                         $this->mDisable = true;
 116                                         $success = false;
 117                                 }*/
 118                                 $this->mCache = false;
 119                         }
 120                 }
 121                 wfProfileOut( $fname );
 122                 $this->mDeferred = false;
 123                 return $success;
 124         }
 125
 126         /**
 127          * Loads all or main part of cacheable messages from the database
 128          */
 129         function loadFromDB() {
 130                 global $wgPartialMessageCache;
 131                 $fname = 'MessageCache::loadFromDB';
 132                 $dbr =& wfGetDB( DB_SLAVE );
 133                 $conditions = array( 'cur_is_redirect' => 0,
 134                                         'cur_namespace' => NS_MEDIAWIKI);
 135                 if ($wgPartialMessageCache) {
 136                         if (is_array($wgPartialMessageCache)) {
 137                                 $conditions['cur_title']=$wgPartialMessageCache;
 138                         } else {
 139                                 require_once("MessageCacheHints.php");
 140                                 $conditions['cur_title']=MessageCacheHints::get();
 141                         }
 142                 }
 143                 $res = $dbr->select( 'cur',
 144                         array( 'cur_title', 'cur_text' ), $conditions, $fname);
 145
 146                 $this->mCache = array();
 147                 for ( $row = $dbr->fetchObject( $res ); $row; $row = $dbr->fetchObject( $res ) ) {
 148                         $this->mCache[$row->cur_title] = $row->cur_text;
 149                 }
 150
 151                 $dbr->freeResult( $res );
 152         }
 153
 154         /**
 155          * Not really needed anymore
 156          */
 157         function getKeys() {
 158                 global $wgAllMessagesEn, $wgContLang;
 159                 if ( !$this->mKeys ) {
 160                         $this->mKeys = array();
 161                         foreach ( $wgAllMessagesEn as $key => $value ) {
 162                                 array_push( $this->mKeys, $wgContLang->ucfirst( $key ) );
 163                         }
 164                 }
 165                 return $this->mKeys;
 166         }
 167
 168         /**
 169          * Obsolete
 170          */
 171         function isCacheable( $key ) {
 172                 return true;
 173                 /*
 174                 global $wgAllMessagesEn, $wgLang;
 175                 return array_key_exists( $wgLang->lcfirst( $key ), $wgAllMessagesEn ) ||
 176                         array_key_exists( $key, $wgAllMessagesEn );
 177                 */
 178         }
 179
 180         function replace( $title, $text ) {
 181                 $this->lock();
 182                 $this->load();
 183                 if ( is_array( $this->mCache ) ) {
 184                         $this->mCache[$title] = $text;
 185                         $this->mMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
 186                 }
 187                 $this->unlock();
 188         }
 189
 190         /**
 191          * Returns success
 192          * Represents a write lock on the messages key
 193          */
 194         function lock() {
 195                 if ( !$this->mUseCache ) {
 196                         return true;
 197                 }
 198
 199                 $lockKey = $this->mMemcKey . 'lock';
 200                 for ($i=0; $i < MSG_WAIT_TIMEOUT && !$this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
 201                         sleep(1);
 202                 }
 203
 204                 return $i >= MSG_WAIT_TIMEOUT;
 205         }
 206
 207         function unlock() {
 208                 if ( !$this->mUseCache ) {
 209                         return;
 210                 }
 211
 212                 $lockKey = $this->mMemcKey . 'lock';
 213                 $this->mMemc->delete( $lockKey );
 214         }
 215
 216         function get( $key, $useDB, $forcontent=true ) {
 217                 global $wgContLanguageCode;
 218                 if( $forcontent ) {
 219                         global $wgContLang;
 220                         $lang =& $wgContLang;
 221                         $langcode = $wgContLanguageCode;
 222                 } else {
 223                         global $wgLang, $wgLanguageCode;
 224                         $lang =& $wgLang;
 225                         $langcode = $wgLanguageCode;
 226                 }
 227                 # If uninitialised, someone is trying to call this halfway through Setup.php
 228                 if( !$this->mInitialised ) {
 229                         return "&lt;$key&gt;";
 230                 }
 231                 # If cache initialization was deferred, start it now.
 232                 if( $this->mDeferred ) {
 233                         $this->load();
 234                 }
 235
 236                 $message = false;
 237                 if( !$this->mDisable && $useDB ) {
 238                         $title = $lang->ucfirst( $key );
 239                         if( $langcode != $wgContLanguageCode ) {
 240                                 $title .= '/' . $langcode;
 241                         }
 242
 243                         # Try the cache
 244                         if( $this->mUseCache && is_array( $this->mCache ) && array_key_exists( $title, $this->mCache ) ) {
 245                                 $message = $this->mCache[$title];
 246                         }
 247
 248                         if ( !$message && $this->mUseCache ) {
 249                                 $message = $this->mMemc->get( $this->mMemcKey . ':' . $title );
 250                                 if( $message ) {
 251                                         $this->mCache[$title] = $message;
 252                                 }
 253                         }
 254
 255                         # If it wasn't in the cache, load each message from the DB individually
 256                         if ( !$message ) {
 257                                 $dbr =& wfGetDB( DB_SLAVE );
 258                                 $result = $dbr->selectRow( 'cur', array('cur_text'),
 259                                   array( 'cur_namespace' => NS_MEDIAWIKI, 'cur_title' => $title ),
 260                                   'MessageCache::get' );
 261                                 if ( $result ) {
 262                                         $message = $result->cur_text;
 263                                         if( $this->mUseCache ) {
 264                                                 $this->mCache[$title] = $message;
 265                                                 /* individual messages may be often
 266                                                    recached until proper purge code exists
 267                                                 */
 268                                                 $this->mMemc->set( $this->mMemcKey . ':' . $title, $message, 300 );
 269                                         }
 270                                 }
 271                         }
 272                 }
 273                 # Try the extension array
 274                 if( !$message ) {
 275                         $message = @$this->mExtensionMessages[$key];
 276                 }
 277
 278                 # Try the array in the language object
 279                 if( !$message ) {
 280                         wfSuppressWarnings();
 281                         $message = $lang->getMessage( $key );
 282                         wfRestoreWarnings();
 283                 }
 284
 285                 # Try the English array
 286                 if( !$message && $langcode != 'en' ) {
 287                         wfSuppressWarnings();
 288                         $message = Language::getMessage( $key );
 289                         wfRestoreWarnings();
 290                 }
 291
 292                 # Final fallback
 293                 if( !$message ) {
 294                         $message = "&lt;$key&gt;";
 295                 }
 296
 297                 # Replace brace tags
 298                 $message = $this->transform( $message );
 299                 return $message;
 300         }
 301
 302         function transform( $message ) {
 303                 if( !$this->mDisableTransform ) {
 304                         if( strpos( $message, '{{' ) !== false ) {
 305                                 $message = $this->mParser->transformMsg( $message, $this->mParserOptions );
 306                         }
 307                 }
 308                 return $message;
 309         }
 310
 311         function disable() { $this->mDisable = true; }
 312         function enable() { $this->mDisable = false; }
 313         function disableTransform() { $this->mDisableTransform = true; }
 314         function enableTransform() { $this->mDisableTransform = false; }
 315
 316         function addMessage( $key, $value ) {
 317                 $this->mExtensionMessages[$key] = $value;
 318         }
 319
 320         function addMessages( $messages ) {
 321                 foreach ( $messages as $key => $value ) {
 322                         $this->mExtensionMessages[$key] = $value;
 323                 }
 324         }
 325
 326         /**
 327          * Clear all stored messages. Mainly used after a mass rebuild.
 328          */
 329         function clear() {
 330                 if( $this->mUseCache ) {
 331                         $this->mMemc->delete( $this->mMemcKey );
 332                 }
 333         }
 334 }
 335 ?>