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