includes/DeferredUpdates.php

   1 <?php
   2 /**
   3  * Interface that deferrable updates should implement. Basically required so we
   4  * can validate input on DeferredUpdates::addUpdate()
   5  *
   6  * @since 1.19
   7  */
   8 interface DeferrableUpdate {
   9         /**
  10          * Perform the actual work
  11          */
  12         function doUpdate();
  13 }
  14
  15 /**
  16  * Class for mananging the deferred updates.
  17  *
  18  * @since 1.19
  19  */
  20 class DeferredUpdates {
  21         /**
  22          * Store of updates to be deferred until the end of the request.
  23          */
  24         private static $updates = array();
  25
  26         /**
  27          * Add an update to the deferred list
  28          * @param $update DeferrableUpdate Some object that implements doUpdate()
  29          */
  30         public static function addUpdate( DeferrableUpdate $update ) {
  31                 array_push( self::$updates, $update );
  32         }
  33
  34         /**
  35          * HTMLCacheUpdates are the most common deferred update people use. This
  36          * is a shortcut method for that.
  37          * @see HTMLCacheUpdate::__construct()
  38          */
  39         public static function addHTMLCacheUpdate( $title, $table ) {
  40                 self::addUpdate( new HTMLCacheUpdate( $title, $table ) );
  41         }
  42
  43         /**
  44          * Do any deferred updates and clear the list
  45          *
  46          * @param $commit String: set to 'commit' to commit after every update to
  47          *                prevent lock contention
  48          */
  49         public static function doUpdates( $commit = '' ) {
  50                 global $wgDeferredUpdateList;
  51
  52                 wfProfileIn( __METHOD__ );
  53
  54                 $updates = array_merge( $wgDeferredUpdateList, self::$updates );
  55
  56                 // No need to get master connections in case of empty updates array
  57                 if ( !count( $updates ) ) {
  58                         wfProfileOut( __METHOD__ );
  59                         return;
  60                 }
  61
  62                 $doCommit = $commit == 'commit';
  63                 if ( $doCommit ) {
  64                         $dbw = wfGetDB( DB_MASTER );
  65                 }
  66
  67                 foreach ( $updates as $update ) {
  68                         $update->doUpdate();
  69
  70                         if ( $doCommit && $dbw->trxLevel() ) {
  71                                 $dbw->commit();
  72                         }
  73                 }
  74
  75                 self::clearPendingUpdates();
  76                 wfProfileOut( __METHOD__ );
  77         }
  78
  79         /**
  80          * Clear all pending updates without performing them. Generally, you don't
  81          * want or need to call this. Unit tests need it though.
  82          */
  83         public static function clearPendingUpdates() {
  84                 global $wgDeferredUpdateList;
  85                 $wgDeferredUpdateList = self::$updates = array();
  86         }
  87 }