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 $self;
  48
  49         /**
  50          * @return ConfigFactory
  51          */
  52         public static function getDefaultInstance() {
  53                 if ( !self::$self ) {
  54                         self::$self = new self;
  55                         global $wgConfigRegistry;
  56                         foreach ( $wgConfigRegistry as $name => $callback ) {
  57                                 self::$self->register( $name, $callback );
  58                         }
  59                 }
  60                 return self::$self;
  61         }
  62
  63         /**
  64          * Destroy the default instance
  65          * Should only be called inside unit tests
  66          * @throws MWException
  67          * @codeCoverageIgnore
  68          */
  69         public static function destroyDefaultInstance() {
  70                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
  71                         throw new MWException( __METHOD__ . ' was called outside of unit tests' );
  72                 }
  73
  74                 self::$self = null;
  75         }
  76
  77         /**
  78          * Register a new config factory function
  79          * Will override if it's already registered
  80          * @param string $name
  81          * @param callable $callback That takes this ConfigFactory as an argument
  82          * @throws InvalidArgumentException If an invalid callback is provided
  83          */
  84         public function register( $name, $callback ) {
  85                 if ( !is_callable( $callback ) ) {
  86                         throw new InvalidArgumentException( 'Invalid callback provided' );
  87                 }
  88                 $this->factoryFunctions[$name] = $callback;
  89         }
  90
  91         /**
  92          * Create a given Config using the registered callback for $name.
  93          * If an object was already created, the same Config object is returned.
  94          * @param string $name Name of the extension/component you want a Config object for
  95          *                     'main' is used for core
  96          * @throws ConfigException If a factory function isn't registered for $name
  97          * @throws UnexpectedValueException If the factory function returns a non-Config object
  98          * @return Config
  99          */
 100         public function makeConfig( $name ) {
 101                 if ( !isset( $this->configs[$name] ) ) {
 102                         if ( !isset( $this->factoryFunctions[$name] ) ) {
 103                                 throw new ConfigException( "No registered builder available for $name." );
 104                         }
 105                         $conf = call_user_func( $this->factoryFunctions[$name], $this );
 106                         if ( $conf instanceof Config ) {
 107                                 $this->configs[$name] = $conf;
 108                         } else {
 109                                 throw new UnexpectedValueException( "The builder for $name returned a non-Config object." );
 110                         }
 111                 }
 112
 113                 return $this->configs[$name];
 114         }
 115 }