includes/filebackend/FileBackendGroup.php

   1 <?php
   2 /**
   3  * File backend 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 FileBackend
  22  * @author Aaron Schulz
  23  */
  24
  25 /**
  26  * Class to handle file backend registration
  27  *
  28  * @ingroup FileBackend
  29  * @since 1.19
  30  */
  31 class FileBackendGroup {
  32         /**
  33          * @var FileBackendGroup
  34          */
  35         protected static $instance = null;
  36
  37         /** @var Array (name => ('class' => string, 'config' => array, 'instance' => object)) */
  38         protected $backends = array();
  39
  40         protected function __construct() {}
  41
  42         /**
  43          * @return FileBackendGroup
  44          */
  45         public static function singleton() {
  46                 if ( self::$instance == null ) {
  47                         self::$instance = new self();
  48                         self::$instance->initFromGlobals();
  49                 }
  50                 return self::$instance;
  51         }
  52
  53         /**
  54          * Destroy the singleton instance
  55          *
  56          * @return void
  57          */
  58         public static function destroySingleton() {
  59                 self::$instance = null;
  60         }
  61
  62         /**
  63          * Register file backends from the global variables
  64          *
  65          * @return void
  66          */
  67         protected function initFromGlobals() {
  68                 global $wgLocalFileRepo, $wgForeignFileRepos, $wgFileBackends;
  69
  70                 // Register explicitly defined backends
  71                 $this->register( $wgFileBackends );
  72
  73                 $autoBackends = array();
  74                 // Automatically create b/c backends for file repos...
  75                 $repos = array_merge( $wgForeignFileRepos, array( $wgLocalFileRepo ) );
  76                 foreach ( $repos as $info ) {
  77                         $backendName = $info['backend'];
  78                         if ( is_object( $backendName ) || isset( $this->backends[$backendName] ) ) {
  79                                 continue; // already defined (or set to the object for some reason)
  80                         }
  81                         $repoName = $info['name'];
  82                         // Local vars that used to be FSRepo members...
  83                         $directory = $info['directory'];
  84                         $deletedDir = isset( $info['deletedDir'] )
  85                                 ? $info['deletedDir']
  86                                 : false; // deletion disabled
  87                         $thumbDir = isset( $info['thumbDir'] )
  88                                 ? $info['thumbDir']
  89                                 : "{$directory}/thumb";
  90                         $transcodedDir = isset( $info['transcodedDir'] )
  91                                 ? $info['transcodedDir']
  92                                 : "{$directory}/transcoded";
  93                         $fileMode = isset( $info['fileMode'] )
  94                                 ? $info['fileMode']
  95                                 : 0644;
  96                         // Get the FS backend configuration
  97                         $autoBackends[] = array(
  98                                 'name' => $backendName,
  99                                 'class' => 'FSFileBackend',
 100                                 'lockManager' => 'fsLockManager',
 101                                 'containerPaths' => array(
 102                                         "{$repoName}-public" => "{$directory}",
 103                                         "{$repoName}-thumb" => $thumbDir,
 104                                         "{$repoName}-transcoded" => $transcodedDir,
 105                                         "{$repoName}-deleted" => $deletedDir,
 106                                         "{$repoName}-temp" => "{$directory}/temp"
 107                                 ),
 108                                 'fileMode' => $fileMode,
 109                         );
 110                 }
 111
 112                 // Register implicitly defined backends
 113                 $this->register( $autoBackends );
 114         }
 115
 116         /**
 117          * Register an array of file backend configurations
 118          *
 119          * @param Array $configs
 120          * @return void
 121          * @throws MWException
 122          */
 123         protected function register( array $configs ) {
 124                 foreach ( $configs as $config ) {
 125                         if ( !isset( $config['name'] ) ) {
 126                                 throw new MWException( "Cannot register a backend with no name." );
 127                         }
 128                         $name = $config['name'];
 129                         if ( isset( $this->backends[$name] ) ) {
 130                                 throw new MWException( "Backend with name `{$name}` already registered." );
 131                         } elseif ( !isset( $config['class'] ) ) {
 132                                 throw new MWException( "Cannot register backend `{$name}` with no class." );
 133                         }
 134                         $class = $config['class'];
 135
 136                         unset( $config['class'] ); // backend won't need this
 137                         $this->backends[$name] = array(
 138                                 'class' => $class,
 139                                 'config' => $config,
 140                                 'instance' => null
 141                         );
 142                 }
 143         }
 144
 145         /**
 146          * Get the backend object with a given name
 147          *
 148          * @param string $name
 149          * @return FileBackend
 150          * @throws MWException
 151          */
 152         public function get( $name ) {
 153                 if ( !isset( $this->backends[$name] ) ) {
 154                         throw new MWException( "No backend defined with the name `$name`." );
 155                 }
 156                 // Lazy-load the actual backend instance
 157                 if ( !isset( $this->backends[$name]['instance'] ) ) {
 158                         $class = $this->backends[$name]['class'];
 159                         $config = $this->backends[$name]['config'];
 160                         $this->backends[$name]['instance'] = new $class( $config );
 161                 }
 162                 return $this->backends[$name]['instance'];
 163         }
 164
 165         /**
 166          * Get the config array for a backend object with a given name
 167          *
 168          * @param string $name
 169          * @return Array
 170          * @throws MWException
 171          */
 172         public function config( $name ) {
 173                 if ( !isset( $this->backends[$name] ) ) {
 174                         throw new MWException( "No backend defined with the name `$name`." );
 175                 }
 176                 $class = $this->backends[$name]['class'];
 177                 return array( 'class' => $class ) + $this->backends[$name]['config'];
 178         }
 179
 180         /**
 181          * Get an appropriate backend object from a storage path
 182          *
 183          * @param string $storagePath
 184          * @return FileBackend|null Backend or null on failure
 185          */
 186         public function backendFromPath( $storagePath ) {
 187                 list( $backend, , ) = FileBackend::splitStoragePath( $storagePath );
 188                 if ( $backend !== null && isset( $this->backends[$backend] ) ) {
 189                         return $this->get( $backend );
 190                 }
 191                 return null;
 192         }
 193 }