includes/Wiki.php

   1 <?php
   2 /**
   3  * Helper class for the index.php entry point.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 /**
  24  * The MediaWiki class is the helper class for the index.php entry point.
  25  *
  26  * @internal documentation reviewed 15 Mar 2010
  27  */
  28 class MediaWiki {
  29
  30         /**
  31          * TODO: fold $output, etc, into this
  32          * @var IContextSource
  33          */
  34         private $context;
  35
  36         /**
  37          * @param $x null|WebRequest
  38          * @return WebRequest
  39          */
  40         public function request( WebRequest $x = null ) {
  41                 $old = $this->context->getRequest();
  42                 $this->context->setRequest( $x );
  43                 return $old;
  44         }
  45
  46         /**
  47          * @param $x null|OutputPage
  48          * @return OutputPage
  49          */
  50         public function output( OutputPage $x = null ) {
  51                 $old = $this->context->getOutput();
  52                 $this->context->setOutput( $x );
  53                 return $old;
  54         }
  55
  56         /**
  57          * @param IContextSource|null $context
  58          */
  59         public function __construct( IContextSource $context = null ) {
  60                 if ( !$context ) {
  61                         $context = RequestContext::getMain();
  62                 }
  63
  64                 $this->context = $context;
  65         }
  66
  67         /**
  68          * Parse the request to get the Title object
  69          *
  70          * @return Title object to be $wgTitle
  71          */
  72         private function parseTitle() {
  73                 global $wgContLang;
  74
  75                 $request = $this->context->getRequest();
  76                 $curid = $request->getInt( 'curid' );
  77                 $title = $request->getVal( 'title' );
  78                 $action = $request->getVal( 'action', 'view' );
  79
  80                 if ( $request->getCheck( 'search' ) ) {
  81                         // Compatibility with old search URLs which didn't use Special:Search
  82                         // Just check for presence here, so blank requests still
  83                         // show the search page when using ugly URLs (bug 8054).
  84                         $ret = SpecialPage::getTitleFor( 'Search' );
  85                 } elseif ( $curid ) {
  86                         // URLs like this are generated by RC, because rc_title isn't always accurate
  87                         $ret = Title::newFromID( $curid );
  88                 } elseif ( $title == '' && $action != 'delete' ) {
  89                         $ret = Title::newMainPage();
  90                 } else {
  91                         $ret = Title::newFromURL( $title );
  92                         // Alias NS_MEDIA page URLs to NS_FILE...we only use NS_MEDIA
  93                         // in wikitext links to tell Parser to make a direct file link
  94                         if ( !is_null( $ret ) && $ret->getNamespace() == NS_MEDIA ) {
  95                                 $ret = Title::makeTitle( NS_FILE, $ret->getDBkey() );
  96                         }
  97                         // Check variant links so that interwiki links don't have to worry
  98                         // about the possible different language variants
  99                         if ( count( $wgContLang->getVariants() ) > 1
 100                                 && !is_null( $ret ) && $ret->getArticleID() == 0 )
 101                         {
 102                                 $wgContLang->findVariantLink( $title, $ret );
 103                         }
 104                 }
 105                 // For non-special titles, check for implicit titles
 106                 if ( is_null( $ret ) || !$ret->isSpecialPage() ) {
 107                         // We can have urls with just ?diff=,?oldid= or even just ?diff=
 108                         $oldid = $request->getInt( 'oldid' );
 109                         $oldid = $oldid ? $oldid : $request->getInt( 'diff' );
 110                         // Allow oldid to override a changed or missing title
 111                         if ( $oldid ) {
 112                                 $rev = Revision::newFromId( $oldid );
 113                                 $ret = $rev ? $rev->getTitle() : $ret;
 114                         }
 115                 }
 116
 117                 if ( $ret === null || ( $ret->getDBkey() == '' && $ret->getInterwiki() == '' ) ) {
 118                         $ret = SpecialPage::getTitleFor( 'Badtitle' );
 119                 }
 120
 121                 return $ret;
 122         }
 123
 124         /**
 125          * Get the Title object that we'll be acting on, as specified in the WebRequest
 126          * @return Title
 127          */
 128         public function getTitle() {
 129                 if( $this->context->getTitle() === null ){
 130                         $this->context->setTitle( $this->parseTitle() );
 131                 }
 132                 return $this->context->getTitle();
 133         }
 134
 135         /**
 136          * Returns the name of the action that will be executed.
 137          *
 138          * @return string: action
 139          */
 140         public function getAction() {
 141                 static $action = null;
 142
 143                 if ( $action === null ) {
 144                         $action = Action::getActionName( $this->context );
 145                 }
 146
 147                 return $action;
 148         }
 149
 150         /**
 151          * Create an Article object of the appropriate class for the given page.
 152          *
 153          * @deprecated in 1.18; use Article::newFromTitle() instead
 154          * @param $title Title
 155          * @param $context IContextSource
 156          * @return Article object
 157          */
 158         public static function articleFromTitle( $title, IContextSource $context ) {
 159                 wfDeprecated( __METHOD__, '1.18' );
 160                 return Article::newFromTitle( $title, $context );
 161         }
 162
 163         /**
 164          * Performs the request.
 165          * - bad titles
 166          * - read restriction
 167          * - local interwiki redirects
 168          * - redirect loop
 169          * - special pages
 170          * - normal pages
 171          *
 172          * @throws MWException|PermissionsError|BadTitleError|HttpError
 173          * @return void
 174          */
 175         private function performRequest() {
 176                 global $wgServer, $wgUsePathInfo, $wgTitle;
 177
 178                 wfProfileIn( __METHOD__ );
 179
 180                 $request = $this->context->getRequest();
 181                 $requestTitle = $title = $this->context->getTitle();
 182                 $output = $this->context->getOutput();
 183                 $user = $this->context->getUser();
 184
 185                 if ( $request->getVal( 'printable' ) === 'yes' ) {
 186                         $output->setPrintable();
 187                 }
 188
 189                 $unused = null; // To pass it by reference
 190                 wfRunHooks( 'BeforeInitialize', array( &$title, &$unused, &$output, &$user, $request, $this ) );
 191
 192                 // Invalid titles. Bug 21776: The interwikis must redirect even if the page name is empty.
 193                 if ( is_null( $title ) || ( $title->getDBkey() == '' && $title->getInterwiki() == '' ) ||
 194                         $title->isSpecial( 'Badtitle' ) )
 195                 {
 196                         $this->context->setTitle( SpecialPage::getTitleFor( 'Badtitle' ) );
 197                         wfProfileOut( __METHOD__ );
 198                         throw new BadTitleError();
 199                 }
 200
 201                 // Check user's permissions to read this page.
 202                 // We have to check here to catch special pages etc.
 203                 // We will check again in Article::view().
 204                 $permErrors = $title->getUserPermissionsErrors( 'read', $user );
 205                 if ( count( $permErrors ) ) {
 206                         // Bug 32276: allowing the skin to generate output with $wgTitle or
 207                         // $this->context->title set to the input title would allow anonymous users to
 208                         // determine whether a page exists, potentially leaking private data. In fact, the
 209                         // curid and oldid request  parameters would allow page titles to be enumerated even
 210                         // when they are not guessable. So we reset the title to Special:Badtitle before the
 211                         // permissions error is displayed.
 212                         //
 213                         // The skin mostly uses $this->context->getTitle() these days, but some extensions
 214                         // still use $wgTitle.
 215
 216                         $badTitle = SpecialPage::getTitleFor( 'Badtitle' );
 217                         $this->context->setTitle( $badTitle );
 218                         $wgTitle = $badTitle;
 219
 220                         wfProfileOut( __METHOD__ );
 221                         throw new PermissionsError( 'read', $permErrors );
 222                 }
 223
 224                 $pageView = false; // was an article or special page viewed?
 225
 226                 // Interwiki redirects
 227                 if ( $title->getInterwiki() != '' ) {
 228                         $rdfrom = $request->getVal( 'rdfrom' );
 229                         if ( $rdfrom ) {
 230                                 $url = $title->getFullURL( 'rdfrom=' . urlencode( $rdfrom ) );
 231                         } else {
 232                                 $query = $request->getValues();
 233                                 unset( $query['title'] );
 234                                 $url = $title->getFullURL( $query );
 235                         }
 236                         // Check for a redirect loop
 237                         if ( !preg_match( '/^' . preg_quote( $wgServer, '/' ) . '/', $url )
 238                                 && $title->isLocal() )
 239                         {
 240                                 // 301 so google et al report the target as the actual url.
 241                                 $output->redirect( $url, 301 );
 242                         } else {
 243                                 $this->context->setTitle( SpecialPage::getTitleFor( 'Badtitle' ) );
 244                                 wfProfileOut( __METHOD__ );
 245                                 throw new BadTitleError();
 246                         }
 247                 // Redirect loops, no title in URL, $wgUsePathInfo URLs, and URLs with a variant
 248                 } elseif ( $request->getVal( 'action', 'view' ) == 'view' && !$request->wasPosted()
 249                         && ( $request->getVal( 'title' ) === null ||
 250                                 $title->getPrefixedDBKey() != $request->getVal( 'title' ) )
 251                         && !count( $request->getValueNames( array( 'action', 'title' ) ) )
 252                         && wfRunHooks( 'TestCanonicalRedirect', array( $request, $title, $output ) ) )
 253                 {
 254                         if ( $title->isSpecialPage() ) {
 255                                 list( $name, $subpage ) = SpecialPageFactory::resolveAlias( $title->getDBkey() );
 256                                 if ( $name ) {
 257                                         $title = SpecialPage::getTitleFor( $name, $subpage );
 258                                 }
 259                         }
 260                         $targetUrl = wfExpandUrl( $title->getFullURL(), PROTO_CURRENT );
 261                         // Redirect to canonical url, make it a 301 to allow caching
 262                         if ( $targetUrl == $request->getFullRequestURL() ) {
 263                                 $message = "Redirect loop detected!\n\n" .
 264                                         "This means the wiki got confused about what page was " .
 265                                         "requested; this sometimes happens when moving a wiki " .
 266                                         "to a new server or changing the server configuration.\n\n";
 267
 268                                 if ( $wgUsePathInfo ) {
 269                                         $message .= "The wiki is trying to interpret the page " .
 270                                                 "title from the URL path portion (PATH_INFO), which " .
 271                                                 "sometimes fails depending on the web server. Try " .
 272                                                 "setting \"\$wgUsePathInfo = false;\" in your " .
 273                                                 "LocalSettings.php, or check that \$wgArticlePath " .
 274                                                 "is correct.";
 275                                 } else {
 276                                         $message .= "Your web server was detected as possibly not " .
 277                                                 "supporting URL path components (PATH_INFO) correctly; " .
 278                                                 "check your LocalSettings.php for a customized " .
 279                                                 "\$wgArticlePath setting and/or toggle \$wgUsePathInfo " .
 280                                                 "to true.";
 281                                 }
 282                                 throw new HttpError( 500, $message );
 283                         } else {
 284                                 $output->setSquidMaxage( 1200 );
 285                                 $output->redirect( $targetUrl, '301' );
 286                         }
 287                 // Special pages
 288                 } elseif ( NS_SPECIAL == $title->getNamespace() ) {
 289                         $pageView = true;
 290                         // Actions that need to be made when we have a special pages
 291                         SpecialPageFactory::executePath( $title, $this->context );
 292                 } else {
 293                         // ...otherwise treat it as an article view. The article
 294                         // may be a redirect to another article or URL.
 295                         $article = $this->initializeArticle();
 296                         if ( is_object( $article ) ) {
 297                                 $pageView = true;
 298                                 /**
 299                                  * $wgArticle is deprecated, do not use it.
 300                                  * @deprecated since 1.18
 301                                  */
 302                                 global $wgArticle;
 303                                 $wgArticle = new DeprecatedGlobal( 'wgArticle', $article, '1.18' );
 304
 305                                 $this->performAction( $article, $requestTitle );
 306                         } elseif ( is_string( $article ) ) {
 307                                 $output->redirect( $article );
 308                         } else {
 309                                 wfProfileOut( __METHOD__ );
 310                                 throw new MWException( "Shouldn't happen: MediaWiki::initializeArticle() returned neither an object nor a URL" );
 311                         }
 312                 }
 313
 314                 if ( $pageView ) {
 315                         // Promote user to any groups they meet the criteria for
 316                         $user->addAutopromoteOnceGroups( 'onView' );
 317                 }
 318
 319                 wfProfileOut( __METHOD__ );
 320         }
 321
 322         /**
 323          * Initialize the main Article object for "standard" actions (view, etc)
 324          * Create an Article object for the page, following redirects if needed.
 325          *
 326          * @return mixed an Article, or a string to redirect to another URL
 327          */
 328         private function initializeArticle() {
 329                 global $wgDisableHardRedirects;
 330
 331                 wfProfileIn( __METHOD__ );
 332
 333                 $title = $this->context->getTitle();
 334                 $article = Article::newFromTitle( $title, $this->context );
 335                 $this->context->setWikiPage( $article->getPage() );
 336                 // NS_MEDIAWIKI has no redirects.
 337                 // It is also used for CSS/JS, so performance matters here...
 338                 if ( $title->getNamespace() == NS_MEDIAWIKI ) {
 339                         wfProfileOut( __METHOD__ );
 340                         return $article;
 341                 }
 342
 343                 $request = $this->context->getRequest();
 344
 345                 // Namespace might change when using redirects
 346                 // Check for redirects ...
 347                 $action = $request->getVal( 'action', 'view' );
 348                 $file = ( $title->getNamespace() == NS_FILE ) ? $article->getFile() : null;
 349                 if ( ( $action == 'view' || $action == 'render' )       // ... for actions that show content
 350                         && !$request->getVal( 'oldid' ) &&    // ... and are not old revisions
 351                         !$request->getVal( 'diff' ) &&    // ... and not when showing diff
 352                         $request->getVal( 'redirect' ) != 'no' &&       // ... unless explicitly told not to
 353                         // ... and the article is not a non-redirect image page with associated file
 354                         !( is_object( $file ) && $file->exists() && !$file->getRedirected() ) )
 355                 {
 356                         // Give extensions a change to ignore/handle redirects as needed
 357                         $ignoreRedirect = $target = false;
 358
 359                         wfRunHooks( 'InitializeArticleMaybeRedirect',
 360                                 array( &$title, &$request, &$ignoreRedirect, &$target, &$article ) );
 361
 362                         // Follow redirects only for... redirects.
 363                         // If $target is set, then a hook wanted to redirect.
 364                         if ( !$ignoreRedirect && ( $target || $article->isRedirect() ) ) {
 365                                 // Is the target already set by an extension?
 366                                 $target = $target ? $target : $article->followRedirect();
 367                                 if ( is_string( $target ) ) {
 368                                         if ( !$wgDisableHardRedirects ) {
 369                                                 // we'll need to redirect
 370                                                 wfProfileOut( __METHOD__ );
 371                                                 return $target;
 372                                         }
 373                                 }
 374                                 if ( is_object( $target ) ) {
 375                                         // Rewrite environment to redirected article
 376                                         $rarticle = Article::newFromTitle( $target, $this->context );
 377                                         $rarticle->loadPageData();
 378                                         if ( $rarticle->exists() || ( is_object( $file ) && !$file->isLocal() ) ) {
 379                                                 $rarticle->setRedirectedFrom( $title );
 380                                                 $article = $rarticle;
 381                                                 $this->context->setTitle( $target );
 382                                                 $this->context->setWikiPage( $article->getPage() );
 383                                         }
 384                                 }
 385                         } else {
 386                                 $this->context->setTitle( $article->getTitle() );
 387                                 $this->context->setWikiPage( $article->getPage() );
 388                         }
 389                 }
 390
 391                 wfProfileOut( __METHOD__ );
 392                 return $article;
 393         }
 394
 395         /**
 396          * Perform one of the "standard" actions
 397          *
 398          * @param $page Page
 399          * @param $requestTitle The original title, before any redirects were applied
 400          */
 401         private function performAction( Page $page, Title $requestTitle ) {
 402                 global $wgUseSquid, $wgSquidMaxage;
 403
 404                 wfProfileIn( __METHOD__ );
 405
 406                 $request = $this->context->getRequest();
 407                 $output = $this->context->getOutput();
 408                 $title = $this->context->getTitle();
 409                 $user = $this->context->getUser();
 410
 411                 if ( !wfRunHooks( 'MediaWikiPerformAction',
 412                         array( $output, $page, $title, $user, $request, $this ) ) )
 413                 {
 414                         wfProfileOut( __METHOD__ );
 415                         return;
 416                 }
 417
 418                 $act = $this->getAction();
 419
 420                 $action = Action::factory( $act, $page );
 421                 if ( $action instanceof Action ) {
 422                         # Let Squid cache things if we can purge them.
 423                         if ( $wgUseSquid &&
 424                                 in_array( $request->getFullRequestURL(), $requestTitle->getSquidURLs() )
 425                         ) {
 426                                 $output->setSquidMaxage( $wgSquidMaxage );
 427                         }
 428
 429                         $action->show();
 430                         wfProfileOut( __METHOD__ );
 431                         return;
 432                 }
 433
 434                 if ( wfRunHooks( 'UnknownAction', array( $request->getVal( 'action', 'view' ), $page ) ) ) {
 435                         $output->showErrorPage( 'nosuchaction', 'nosuchactiontext' );
 436                 }
 437
 438                 wfProfileOut( __METHOD__ );
 439         }
 440
 441         /**
 442          * Run the current MediaWiki instance
 443          * index.php just calls this
 444          */
 445         public function run() {
 446                 try {
 447                         $this->checkMaxLag();
 448                         $this->main();
 449                         $this->restInPeace();
 450                 } catch ( Exception $e ) {
 451                         MWExceptionHandler::handle( $e );
 452                 }
 453         }
 454
 455         /**
 456          * Checks if the request should abort due to a lagged server,
 457          * for given maxlag parameter.
 458          * @return bool
 459          */
 460         private function checkMaxLag() {
 461                 global $wgShowHostnames;
 462
 463                 wfProfileIn( __METHOD__ );
 464                 $maxLag = $this->context->getRequest()->getVal( 'maxlag' );
 465                 if ( !is_null( $maxLag ) ) {
 466                         list( $host, $lag ) = wfGetLB()->getMaxLag();
 467                         if ( $lag > $maxLag ) {
 468                                 $resp = $this->context->getRequest()->response();
 469                                 $resp->header( 'HTTP/1.1 503 Service Unavailable' );
 470                                 $resp->header( 'Retry-After: ' . max( intval( $maxLag ), 5 ) );
 471                                 $resp->header( 'X-Database-Lag: ' . intval( $lag ) );
 472                                 $resp->header( 'Content-Type: text/plain' );
 473                                 if( $wgShowHostnames ) {
 474                                         echo "Waiting for $host: $lag seconds lagged\n";
 475                                 } else {
 476                                         echo "Waiting for a database server: $lag seconds lagged\n";
 477                                 }
 478
 479                                 wfProfileOut( __METHOD__ );
 480
 481                                 exit;
 482                         }
 483                 }
 484                 wfProfileOut( __METHOD__ );
 485                 return true;
 486         }
 487
 488         private function main() {
 489                 global $wgUseFileCache, $wgTitle, $wgUseAjax;
 490
 491                 wfProfileIn( __METHOD__ );
 492
 493                 $request = $this->context->getRequest();
 494
 495                 if ( $request->getCookie( 'forceHTTPS' )
 496                         && $request->detectProtocol() == 'http'
 497                         && $request->getMethod() == 'GET'
 498                 ) {
 499                         $redirUrl = $request->getFullRequestURL();
 500                         $redirUrl = str_replace( 'http://' , 'https://' , $redirUrl );
 501
 502                         // Setup dummy Title, otherwise OutputPage::redirect will fail
 503                         $title = Title::newFromText( NS_MAIN, 'REDIR' );
 504                         $this->context->setTitle( $title );
 505                         $output = $this->context->getOutput();
 506                         $output->redirect( $redirUrl );
 507                         $output->output();
 508                         wfProfileOut( __METHOD__ );
 509                         return;
 510                 }
 511
 512                 // Send Ajax requests to the Ajax dispatcher.
 513                 if ( $wgUseAjax && $request->getVal( 'action', 'view' ) == 'ajax' ) {
 514
 515                         // Set a dummy title, because $wgTitle == null might break things
 516                         $title = Title::makeTitle( NS_MAIN, 'AJAX' );
 517                         $this->context->setTitle( $title );
 518                         $wgTitle = $title;
 519
 520                         $dispatcher = new AjaxDispatcher();
 521                         $dispatcher->performAction();
 522                         wfProfileOut( __METHOD__ );
 523                         return;
 524                 }
 525
 526                 // Get title from request parameters,
 527                 // is set on the fly by parseTitle the first time.
 528                 $title = $this->getTitle();
 529                 $action = $this->getAction();
 530                 $wgTitle = $title;
 531
 532                 if ( $wgUseFileCache && $title->getNamespace() >= 0 ) {
 533                         wfProfileIn( 'main-try-filecache' );
 534                         if ( HTMLFileCache::useFileCache( $this->context ) ) {
 535                                 // Try low-level file cache hit
 536                                 $cache = HTMLFileCache::newFromTitle( $title, $action );
 537                                 if ( $cache->isCacheGood( /* Assume up to date */ ) ) {
 538                                         // Check incoming headers to see if client has this cached
 539                                         $timestamp = $cache->cacheTimestamp();
 540                                         if ( !$this->context->getOutput()->checkLastModified( $timestamp ) ) {
 541                                                 $cache->loadFromFileCache( $this->context );
 542                                         }
 543                                         // Do any stats increment/watchlist stuff
 544                                         $this->context->getWikiPage()->doViewUpdates( $this->context->getUser() );
 545                                         // Tell OutputPage that output is taken care of
 546                                         $this->context->getOutput()->disable();
 547                                         wfProfileOut( 'main-try-filecache' );
 548                                         wfProfileOut( __METHOD__ );
 549                                         return;
 550                                 }
 551                         }
 552                         wfProfileOut( 'main-try-filecache' );
 553                 }
 554
 555                 $this->performRequest();
 556
 557                 // Now commit any transactions, so that unreported errors after
 558                 // output() don't roll back the whole DB transaction
 559                 wfGetLBFactory()->commitMasterChanges();
 560
 561                 // Output everything!
 562                 $this->context->getOutput()->output();
 563
 564                 wfProfileOut( __METHOD__ );
 565         }
 566
 567         /**
 568          * Ends this task peacefully
 569          */
 570         public function restInPeace() {
 571                 // Do any deferred jobs
 572                 DeferredUpdates::doUpdates( 'commit' );
 573
 574                 // Execute a job from the queue
 575                 $this->doJobs();
 576
 577                 // Log message usage, if $wgAdaptiveMessageCache is set to true
 578                 MessageCache::logMessages();
 579
 580                 // Log profiling data, e.g. in the database or UDP
 581                 wfLogProfilingData();
 582
 583                 // Commit and close up!
 584                 $factory = wfGetLBFactory();
 585                 $factory->commitMasterChanges();
 586                 $factory->shutdown();
 587
 588                 wfDebug( "Request ended normally\n" );
 589         }
 590
 591         /**
 592          * Do a job from the job queue
 593          */
 594         private function doJobs() {
 595                 global $wgJobRunRate;
 596
 597                 if ( $wgJobRunRate <= 0 || wfReadOnly() ) {
 598                         return;
 599                 }
 600
 601                 if ( $wgJobRunRate < 1 ) {
 602                         $max = mt_getrandmax();
 603                         if ( mt_rand( 0, $max ) > $max * $wgJobRunRate ) {
 604                                 return; // the higher $wgJobRunRate, the less likely we return here
 605                         }
 606                         $n = 1;
 607                 } else {
 608                         $n = intval( $wgJobRunRate );
 609                 }
 610
 611                 $group = JobQueueGroup::singleton();
 612                 $types = $group->getDefaultQueueTypes();
 613                 shuffle( $types ); // avoid starvation
 614
 615                 // Scan the queues for a job N times...
 616                 do {
 617                         $jobFound = false; // found a job in any queue?
 618                         // Find a queue with a job on it and run it...
 619                         foreach ( $types as $i => $type ) {
 620                                 $queue = $group->get( $type );
 621                                 if ( $queue->isEmpty() ) {
 622                                         unset( $types[$i] ); // don't keep checking this queue
 623                                         continue;
 624                                 }
 625                                 $job = $queue->pop();
 626                                 if ( $job ) {
 627                                         $jobFound = true;
 628                                         $output = $job->toString() . "\n";
 629                                         $t = - microtime( true );
 630                                         $success = $job->run();
 631                                         $queue->ack( $job ); // done
 632                                         $t += microtime( true );
 633                                         $t = round( $t * 1000 );
 634                                         if ( !$success ) {
 635                                                 $output .= "Error: " . $job->getLastError() . ", Time: $t ms\n";
 636                                         } else {
 637                                                 $output .= "Success, Time: $t ms\n";
 638                                         }
 639                                         wfDebugLog( 'jobqueue', $output );
 640                                         break;
 641                                 } else {
 642                                         unset( $types[$i] ); // don't keep checking this queue
 643                                 }
 644                         }
 645                 } while ( --$n && $jobFound );
 646         }
 647 }