includes/config/ConfigFactory.php

   1 <?php
   2
   3 /**
   4  * Copyright 2014
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19  * http://www.gnu.org/copyleft/gpl.html
  20  *
  21  * @file
  22  */
  23
  24 /**
  25  * Factory class to create Config objects
  26  *
  27  * @since 1.23
  28  */
  29 class ConfigFactory {
  30
  31         /**
  32          * Map of config name => callback
  33          * @var array
  34          */
  35         protected $factoryFunctions = array();
  36
  37         /**
  38          * Config objects that have already been created
  39          * name => Config object
  40          * @var array
  41          */
  42         protected $configs = array();
  43
  44         public static function getDefaultInstance() {
  45                 static $self = null;
  46                 if ( !$self ) {
  47                         $self = new self;
  48                         global $wgConfigRegistry;
  49                         foreach ( $wgConfigRegistry as $name => $callback ) {
  50                                 $self->register( $name, $callback );
  51                         }
  52                 }
  53                 return $self;
  54         }
  55
  56         /**
  57          * Register a new config factory function
  58          * Will override if it's already registered
  59          * @param string $name
  60          * @param callable $callback that takes this ConfigFactory as an argument
  61          * @throws InvalidArgumentException if an invalid callback is provided
  62          */
  63         public function register( $name, $callback ) {
  64                 if ( !is_callable( $callback ) ) {
  65                         throw new InvalidArgumentException( 'Invalid callback provided' );
  66                 }
  67                 $this->factoryFunctions[$name] = $callback;
  68         }
  69
  70         /**
  71          * Create a given Config using the registered callback for $name.
  72          * If an object was already created, the same Config object is returned.
  73          * @param string $name of the extension/component you want a Config object for
  74          *                     'main' is used for core
  75          * @throws ConfigException if a factory function isn't registered for $name
  76          * @throws UnexpectedValueException if the factory function returns a non-Config object
  77          * @return Config
  78          */
  79         public function makeConfig( $name ) {
  80                 if ( !isset( $this->configs[$name] ) ) {
  81                         if ( !isset( $this->factoryFunctions[$name] ) ) {
  82                                 throw new ConfigException( "No registered builder available for $name." );
  83                         }
  84                         $conf = call_user_func( $this->factoryFunctions[$name], $this );
  85                         if ( $conf instanceof Config ) {
  86                                 $this->configs[$name] = $conf;
  87                         } else {
  88                                 throw new UnexpectedValueException( "The builder for $name returned a non-Config object." );
  89                         }
  90                 }
  91
  92                 return $this->configs[$name];
  93         }
  94 }