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 $backends = array();
  39
  40         protected function __construct() {
  41         }
  42
  43         /**
  44          * @return FileBackendGroup
  45          */
  46         public static function singleton() {
  47                 if ( self::$instance == null ) {
  48                         self::$instance = new self();
  49                         self::$instance->initFromGlobals();
  50                 }
  51
  52                 return self::$instance;
  53         }
  54
  55         /**
  56          * Destroy the singleton instance
  57          *
  58          * @return void
  59          */
  60         public static function destroySingleton() {
  61                 self::$instance = null;
  62         }
  63
  64         /**
  65          * Register file backends from the global variables
  66          *
  67          * @return void
  68          */
  69         protected function initFromGlobals() {
  70                 global $wgLocalFileRepo, $wgForeignFileRepos, $wgFileBackends;
  71
  72                 // Register explicitly defined backends
  73                 $this->register( $wgFileBackends );
  74
  75                 $autoBackends = array();
  76                 // Automatically create b/c backends for file repos...
  77                 $repos = array_merge( $wgForeignFileRepos, array( $wgLocalFileRepo ) );
  78                 foreach ( $repos as $info ) {
  79                         $backendName = $info['backend'];
  80                         if ( is_object( $backendName ) || isset( $this->backends[$backendName] ) ) {
  81                                 continue; // already defined (or set to the object for some reason)
  82                         }
  83                         $repoName = $info['name'];
  84                         // Local vars that used to be FSRepo members...
  85                         $directory = $info['directory'];
  86                         $deletedDir = isset( $info['deletedDir'] )
  87                                 ? $info['deletedDir']
  88                                 : false; // deletion disabled
  89                         $thumbDir = isset( $info['thumbDir'] )
  90                                 ? $info['thumbDir']
  91                                 : "{$directory}/thumb";
  92                         $transcodedDir = isset( $info['transcodedDir'] )
  93                                 ? $info['transcodedDir']
  94                                 : "{$directory}/transcoded";
  95                         $fileMode = isset( $info['fileMode'] )
  96                                 ? $info['fileMode']
  97                                 : 0644;
  98                         // Get the FS backend configuration
  99                         $autoBackends[] = array(
 100                                 'name' => $backendName,
 101                                 'class' => 'FSFileBackend',
 102                                 'lockManager' => 'fsLockManager',
 103                                 'containerPaths' => array(
 104                                         "{$repoName}-public" => "{$directory}",
 105                                         "{$repoName}-thumb" => $thumbDir,
 106                                         "{$repoName}-transcoded" => $transcodedDir,
 107                                         "{$repoName}-deleted" => $deletedDir,
 108                                         "{$repoName}-temp" => "{$directory}/temp"
 109                                 ),
 110                                 'fileMode' => $fileMode,
 111                         );
 112                 }
 113
 114                 // Register implicitly defined backends
 115                 $this->register( $autoBackends );
 116         }
 117
 118         /**
 119          * Register an array of file backend configurations
 120          *
 121          * @param Array $configs
 122          * @return void
 123          * @throws MWException
 124          */
 125         protected function register( array $configs ) {
 126                 foreach ( $configs as $config ) {
 127                         if ( !isset( $config['name'] ) ) {
 128                                 throw new MWException( "Cannot register a backend with no name." );
 129                         }
 130                         $name = $config['name'];
 131                         if ( isset( $this->backends[$name] ) ) {
 132                                 throw new MWException( "Backend with name `{$name}` already registered." );
 133                         } elseif ( !isset( $config['class'] ) ) {
 134                                 throw new MWException( "Cannot register backend `{$name}` with no class." );
 135                         }
 136                         $class = $config['class'];
 137
 138                         unset( $config['class'] ); // backend won't need this
 139                         $this->backends[$name] = array(
 140                                 'class' => $class,
 141                                 'config' => $config,
 142                                 'instance' => null
 143                         );
 144                 }
 145         }
 146
 147         /**
 148          * Get the backend object with a given name
 149          *
 150          * @param string $name
 151          * @return FileBackend
 152          * @throws MWException
 153          */
 154         public function get( $name ) {
 155                 if ( !isset( $this->backends[$name] ) ) {
 156                         throw new MWException( "No backend defined with the name `$name`." );
 157                 }
 158                 // Lazy-load the actual backend instance
 159                 if ( !isset( $this->backends[$name]['instance'] ) ) {
 160                         $class = $this->backends[$name]['class'];
 161                         $config = $this->backends[$name]['config'];
 162                         $this->backends[$name]['instance'] = new $class( $config );
 163                 }
 164
 165                 return $this->backends[$name]['instance'];
 166         }
 167
 168         /**
 169          * Get the config array for a backend object with a given name
 170          *
 171          * @param string $name
 172          * @return Array
 173          * @throws MWException
 174          */
 175         public function config( $name ) {
 176                 if ( !isset( $this->backends[$name] ) ) {
 177                         throw new MWException( "No backend defined with the name `$name`." );
 178                 }
 179                 $class = $this->backends[$name]['class'];
 180
 181                 return array( 'class' => $class ) + $this->backends[$name]['config'];
 182         }
 183
 184         /**
 185          * Get an appropriate backend object from a storage path
 186          *
 187          * @param string $storagePath
 188          * @return FileBackend|null Backend or null on failure
 189          */
 190         public function backendFromPath( $storagePath ) {
 191                 list( $backend, , ) = FileBackend::splitStoragePath( $storagePath );
 192                 if ( $backend !== null && isset( $this->backends[$backend] ) ) {
 193                         return $this->get( $backend );
 194                 }
 195
 196                 return null;
 197         }
 198 }