includes/filerepo/backend/FileBackendGroup.php

   1 <?php
   2 /**
   3  * @file
   4  * @ingroup FileBackend
   5  */
   6
   7 /**
   8  * Class to handle file backend registration
   9  *
  10  * @ingroup FileBackend
  11  */
  12 class FileBackendGroup {
  13         protected static $instance = null;
  14
  15         /** @var Array of (name => ('class' =>, 'config' =>, 'instance' =>)) */
  16         protected $backends = array();
  17
  18         protected function __construct() {}
  19         protected function __clone() {}
  20
  21         public static function singleton() {
  22                 if ( self::$instance == null ) {
  23                         self::$instance = new self();
  24                 }
  25                 return self::$instance;
  26         }
  27
  28         /**
  29          * Destroy the singleton instance, so that a new one will be created next
  30          * time singleton() is called.
  31          */
  32         public static function destroySingleton() {
  33                 self::$instance = null;
  34         }
  35
  36         /**
  37          * Register an array of file backend configurations
  38          *
  39          * @param $configs Array
  40          * @return void
  41          * @throws MWException
  42          */
  43         public function register( array $configs ) {
  44                 foreach ( $configs as $config ) {
  45                         if ( !isset( $config['name'] ) ) {
  46                                 throw new MWException( "Cannot register a backend with no name." );
  47                         }
  48                         $name = $config['name'];
  49                         if ( !isset( $config['class'] ) ) {
  50                                 throw new MWException( "Cannot register backend `{$name}` with no class." );
  51                         }
  52                         $class = $config['class'];
  53
  54                         unset( $config['class'] ); // backend won't need this
  55                         $this->backends[$name] = array(
  56                                 'class'    => $class,
  57                                 'config'   => $config,
  58                                 'instance' => null
  59                         );
  60                 }
  61         }
  62
  63         /**
  64          * Get the backend object with a given name
  65          *
  66          * @param $name string
  67          * @return FileBackendBase
  68          * @throws MWException
  69          */
  70         public function get( $name ) {
  71                 if ( !isset( $this->backends[$name] ) ) {
  72                         throw new MWException( "No backend defined with the name `$name`." );
  73                 }
  74                 // Lazy-load the actual backend instance
  75                 if ( !isset( $this->backends[$name]['instance'] ) ) {
  76                         $class = $this->backends[$name]['class'];
  77                         $config = $this->backends[$name]['config'];
  78                         $this->backends[$name]['instance'] = new $class( $config );
  79                 }
  80                 return $this->backends[$name]['instance'];
  81         }
  82
  83         /**
  84          * Get an appropriate backend object from a storage path
  85          *
  86          * @param $storagePath string
  87          * @return FileBackendBase|null Backend or null on failure
  88          */
  89         public function backendFromPath( $storagePath ) {
  90                 list( $backend, $c, $p ) = FileBackend::splitStoragePath( $storagePath );
  91                 if ( $backend !== null && isset( $this->backends[$backend] ) ) {
  92                         return $this->get( $backend );
  93                 }
  94                 return null;
  95         }
  96 }