includes/filerepo/backend/lockmanager/LockManagerGroup.php

   1 <?php
   2 /**
   3  * Lock manager registration handling.
   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  * @ingroup LockManager
  22  */
  23
  24 /**
  25  * Class to handle file lock manager registration
  26  *
  27  * @ingroup LockManager
  28  * @author Aaron Schulz
  29  * @since 1.19
  30  */
  31 class LockManagerGroup {
  32
  33         /**
  34          * @var LockManagerGroup
  35          */
  36         protected static $instance = null;
  37
  38         /** @var Array of (name => ('class' =>, 'config' =>, 'instance' =>)) */
  39         protected $managers = array();
  40
  41         protected function __construct() {}
  42
  43         /**
  44          * @return LockManagerGroup
  45          */
  46         public static function singleton() {
  47                 if ( self::$instance == null ) {
  48                         self::$instance = new self();
  49                         self::$instance->initFromGlobals();
  50                 }
  51                 return self::$instance;
  52         }
  53
  54         /**
  55          * Destroy the singleton instance, so that a new one will be created next
  56          * time singleton() is called.
  57          */
  58         public static function destroySingleton() {
  59                 self::$instance = null;
  60         }
  61
  62         /**
  63          * Register lock managers from the global variables
  64          *
  65          * @return void
  66          */
  67         protected function initFromGlobals() {
  68                 global $wgLockManagers;
  69
  70                 $this->register( $wgLockManagers );
  71         }
  72
  73         /**
  74          * Register an array of file lock manager configurations
  75          *
  76          * @param $configs Array
  77          * @return void
  78          * @throws MWException
  79          */
  80         protected function register( array $configs ) {
  81                 foreach ( $configs as $config ) {
  82                         if ( !isset( $config['name'] ) ) {
  83                                 throw new MWException( "Cannot register a lock manager with no name." );
  84                         }
  85                         $name = $config['name'];
  86                         if ( !isset( $config['class'] ) ) {
  87                                 throw new MWException( "Cannot register lock manager `{$name}` with no class." );
  88                         }
  89                         $class = $config['class'];
  90                         unset( $config['class'] ); // lock manager won't need this
  91                         $this->managers[$name] = array(
  92                                 'class'    => $class,
  93                                 'config'   => $config,
  94                                 'instance' => null
  95                         );
  96                 }
  97         }
  98
  99         /**
 100          * Get the lock manager object with a given name
 101          *
 102          * @param $name string
 103          * @return LockManager
 104          * @throws MWException
 105          */
 106         public function get( $name ) {
 107                 if ( !isset( $this->managers[$name] ) ) {
 108                         throw new MWException( "No lock manager defined with the name `$name`." );
 109                 }
 110                 // Lazy-load the actual lock manager instance
 111                 if ( !isset( $this->managers[$name]['instance'] ) ) {
 112                         $class = $this->managers[$name]['class'];
 113                         $config = $this->managers[$name]['config'];
 114                         $this->managers[$name]['instance'] = new $class( $config );
 115                 }
 116                 return $this->managers[$name]['instance'];
 117         }
 118 }