includes/ScopedCallback.php

   1 <?php
   2 /**
   3  * This file deals with RAII style scoped callbacks.
   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  * Class for asserting that a callback happens when an dummy object leaves scope
  25  *
  26  * @since 1.21
  27  */
  28 class ScopedCallback {
  29         /** @var callable */
  30         protected $callback;
  31
  32         /**
  33          * @param callable $callback
  34          * @throws MWException
  35          */
  36         public function __construct( $callback ) {
  37                 if ( !is_callable( $callback ) ) {
  38                         throw new MWException( "Provided callback is not valid." );
  39                 }
  40                 $this->callback = $callback;
  41         }
  42
  43         /**
  44          * Trigger a scoped callback and destroy it.
  45          * This is the same is just setting it to null.
  46          *
  47          * @param ScopedCallback $sc
  48          */
  49         public static function consume( ScopedCallback &$sc = null ) {
  50                 $sc = null;
  51         }
  52
  53         /**
  54          * Destroy a scoped callback without triggering it
  55          *
  56          * @param ScopedCallback $sc
  57          */
  58         public static function cancel( ScopedCallback &$sc = null ) {
  59                 if ( $sc ) {
  60                         $sc->callback = null;
  61                 }
  62                 $sc = null;
  63         }
  64
  65         /**
  66          * Trigger the callback when this leaves scope
  67          */
  68         function __destruct() {
  69                 if ( $this->callback !== null ) {
  70                         call_user_func( $this->callback );
  71                 }
  72         }
  73 }