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         /**
  45          * @var ConfigFactory
  46          */
  47         private static $self;
  48
  49         public static function getDefaultInstance() {
  50                 if ( !self::$self ) {
  51                         self::$self = new self;
  52                         global $wgConfigRegistry;
  53                         foreach ( $wgConfigRegistry as $name => $callback ) {
  54                                 self::$self->register( $name, $callback );
  55                         }
  56                 }
  57                 return self::$self;
  58         }
  59
  60         /**
  61          * Destroy the default instance
  62          * Should only be called inside unit tests
  63          * @throws MWException
  64          */
  65         public static function destroyDefaultInstance() {
  66                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
  67                         throw new MWException( __METHOD__ . ' was called outside of unit tests' );
  68                 }
  69
  70                 self::$self = null;
  71         }
  72
  73         /**
  74          * Register a new config factory function
  75          * Will override if it's already registered
  76          * @param string $name
  77          * @param callable $callback That takes this ConfigFactory as an argument
  78          * @throws InvalidArgumentException If an invalid callback is provided
  79          */
  80         public function register( $name, $callback ) {
  81                 if ( !is_callable( $callback ) ) {
  82                         throw new InvalidArgumentException( 'Invalid callback provided' );
  83                 }
  84                 $this->factoryFunctions[$name] = $callback;
  85         }
  86
  87         /**
  88          * Create a given Config using the registered callback for $name.
  89          * If an object was already created, the same Config object is returned.
  90          * @param string $name Name of the extension/component you want a Config object for
  91          *                     'main' is used for core
  92          * @throws ConfigException If a factory function isn't registered for $name
  93          * @throws UnexpectedValueException If the factory function returns a non-Config object
  94          * @return Config
  95          */
  96         public function makeConfig( $name ) {
  97                 if ( !isset( $this->configs[$name] ) ) {
  98                         if ( !isset( $this->factoryFunctions[$name] ) ) {
  99                                 throw new ConfigException( "No registered builder available for $name." );
 100                         }
 101                         $conf = call_user_func( $this->factoryFunctions[$name], $this );
 102                         if ( $conf instanceof Config ) {
 103                                 $this->configs[$name] = $conf;
 104                         } else {
 105                                 throw new UnexpectedValueException( "The builder for $name returned a non-Config object." );
 106                         }
 107                 }
 108
 109                 return $this->configs[$name];
 110         }
 111 }