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         /** @var array (domain => LockManager) */
  33         protected static $instances = array();
  34
  35         protected $domain; // string; domain (usually wiki ID)
  36
  37         /** @var array Array of (name => ('class' => ..., 'config' => ..., 'instance' => ...)) */
  38         protected $managers = array();
  39
  40         /**
  41          * @param string $domain Domain (usually wiki ID)
  42          */
  43         protected function __construct( $domain ) {
  44                 $this->domain = $domain;
  45         }
  46
  47         /**
  48          * @param bool|string $domain Domain (usually wiki ID). Default: false.
  49          * @return LockManagerGroup
  50          */
  51         public static function singleton( $domain = false ) {
  52                 $domain = ( $domain === false ) ? wfWikiID() : $domain;
  53                 if ( !isset( self::$instances[$domain] ) ) {
  54                         self::$instances[$domain] = new self( $domain );
  55                         self::$instances[$domain]->initFromGlobals();
  56                 }
  57
  58                 return self::$instances[$domain];
  59         }
  60
  61         /**
  62          * Destroy the singleton instances
  63          */
  64         public static function destroySingletons() {
  65                 self::$instances = array();
  66         }
  67
  68         /**
  69          * Register lock managers from the global variables
  70          */
  71         protected function initFromGlobals() {
  72                 global $wgLockManagers;
  73
  74                 $this->register( $wgLockManagers );
  75         }
  76
  77         /**
  78          * Register an array of file lock manager configurations
  79          *
  80          * @param array $configs
  81          * @throws MWException
  82          */
  83         protected function register( array $configs ) {
  84                 foreach ( $configs as $config ) {
  85                         $config['domain'] = $this->domain;
  86                         if ( !isset( $config['name'] ) ) {
  87                                 throw new MWException( "Cannot register a lock manager with no name." );
  88                         }
  89                         $name = $config['name'];
  90                         if ( !isset( $config['class'] ) ) {
  91                                 throw new MWException( "Cannot register lock manager `{$name}` with no class." );
  92                         }
  93                         $class = $config['class'];
  94                         unset( $config['class'] ); // lock manager won't need this
  95                         $this->managers[$name] = array(
  96                                 'class' => $class,
  97                                 'config' => $config,
  98                                 'instance' => null
  99                         );
 100                 }
 101         }
 102
 103         /**
 104          * Get the lock manager object with a given name
 105          *
 106          * @param string $name
 107          * @return LockManager
 108          * @throws MWException
 109          */
 110         public function get( $name ) {
 111                 if ( !isset( $this->managers[$name] ) ) {
 112                         throw new MWException( "No lock manager defined with the name `$name`." );
 113                 }
 114                 // Lazy-load the actual lock manager instance
 115                 if ( !isset( $this->managers[$name]['instance'] ) ) {
 116                         $class = $this->managers[$name]['class'];
 117                         $config = $this->managers[$name]['config'];
 118                         $this->managers[$name]['instance'] = new $class( $config );
 119                 }
 120
 121                 return $this->managers[$name]['instance'];
 122         }
 123
 124         /**
 125          * Get the config array for a lock manager object with a given name
 126          *
 127          * @param string $name
 128          * @return array
 129          * @throws MWException
 130          */
 131         public function config( $name ) {
 132                 if ( !isset( $this->managers[$name] ) ) {
 133                         throw new MWException( "No lock manager defined with the name `$name`." );
 134                 }
 135                 $class = $this->managers[$name]['class'];
 136
 137                 return array( 'class' => $class ) + $this->managers[$name]['config'];
 138         }
 139
 140         /**
 141          * Get the default lock manager configured for the site.
 142          * Returns NullLockManager if no lock manager could be found.
 143          *
 144          * @return LockManager
 145          */
 146         public function getDefault() {
 147                 return isset( $this->managers['default'] )
 148                         ? $this->get( 'default' )
 149                         : new NullLockManager( array() );
 150         }
 151
 152         /**
 153          * Get the default lock manager configured for the site
 154          * or at least some other effective configured lock manager.
 155          * Throws an exception if no lock manager could be found.
 156          *
 157          * @return LockManager
 158          * @throws MWException
 159          */
 160         public function getAny() {
 161                 return isset( $this->managers['default'] )
 162                         ? $this->get( 'default' )
 163                         : $this->get( 'fsLockManager' );
 164         }
 165 }