includes/filebackend/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          * @var LockManagerGroup
  34          */
  35         protected static $instance = null;
  36
  37         /** @var Array of (name => ('class' =>, 'config' =>, 'instance' =>)) */
  38         protected $managers = array();
  39
  40         protected function __construct() {}
  41
  42         /**
  43          * @return LockManagerGroup
  44          */
  45         public static function singleton() {
  46                 if ( self::$instance == null ) {
  47                         self::$instance = new self();
  48                         self::$instance->initFromGlobals();
  49                 }
  50                 return self::$instance;
  51         }
  52
  53         /**
  54          * Destroy the singleton instance, so that a new one will be created next
  55          * time singleton() is called.
  56          */
  57         public static function destroySingleton() {
  58                 self::$instance = null;
  59         }
  60
  61         /**
  62          * Register lock managers from the global variables
  63          *
  64          * @return void
  65          */
  66         protected function initFromGlobals() {
  67                 global $wgLockManagers;
  68
  69                 $this->register( $wgLockManagers );
  70         }
  71
  72         /**
  73          * Register an array of file lock manager configurations
  74          *
  75          * @param $configs Array
  76          * @return void
  77          * @throws MWException
  78          */
  79         protected function register( array $configs ) {
  80                 foreach ( $configs as $config ) {
  81                         if ( !isset( $config['name'] ) ) {
  82                                 throw new MWException( "Cannot register a lock manager with no name." );
  83                         }
  84                         $name = $config['name'];
  85                         if ( !isset( $config['class'] ) ) {
  86                                 throw new MWException( "Cannot register lock manager `{$name}` with no class." );
  87                         }
  88                         $class = $config['class'];
  89                         unset( $config['class'] ); // lock manager won't need this
  90                         $this->managers[$name] = array(
  91                                 'class'    => $class,
  92                                 'config'   => $config,
  93                                 'instance' => null
  94                         );
  95                 }
  96         }
  97
  98         /**
  99          * Get the lock manager object with a given name
 100          *
 101          * @param $name string
 102          * @return LockManager
 103          * @throws MWException
 104          */
 105         public function get( $name ) {
 106                 if ( !isset( $this->managers[$name] ) ) {
 107                         throw new MWException( "No lock manager defined with the name `$name`." );
 108                 }
 109                 // Lazy-load the actual lock manager instance
 110                 if ( !isset( $this->managers[$name]['instance'] ) ) {
 111                         $class = $this->managers[$name]['class'];
 112                         $config = $this->managers[$name]['config'];
 113                         $this->managers[$name]['instance'] = new $class( $config );
 114                 }
 115                 return $this->managers[$name]['instance'];
 116         }
 117
 118         /**
 119          * Get the default lock manager configured for the site.
 120          * Returns NullLockManager if no lock manager could be found.
 121          *
 122          * @return LockManager
 123          */
 124         public function getDefault() {
 125                 return isset( $this->managers['default'] )
 126                         ? $this->get( 'default' )
 127                         : new NullLockManager( array() );
 128         }
 129
 130         /**
 131          * Get the default lock manager configured for the site
 132          * or at least some other effective configured lock manager.
 133          * Throws an exception if no lock manager could be found.
 134          *
 135          * @return LockManager
 136          * @throws MWException
 137          */
 138         public function getAny() {
 139                 return isset( $this->managers['default'] )
 140                         ? $this->get( 'default' )
 141                         : $this->get( 'fsLockManager' );
 142         }
 143 }