includes/api/ApiModuleManager.php

   1 <?php
   2 /**
   3  * Copyright © 2012 Yuri Astrakhan "<Firstname><Lastname>@gmail.com"
   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  * @since 1.21
  22  */
  23
  24 /**
  25  * This class holds a list of modules and handles instantiation
  26  *
  27  * @since 1.21
  28  * @ingroup API
  29  */
  30 class ApiModuleManager extends ContextSource {
  31
  32         /**
  33          * @var ApiBase
  34          */
  35         private $mParent;
  36         /**
  37          * @var ApiBase[]
  38          */
  39         private $mInstances = [];
  40         /**
  41          * @var null[]
  42          */
  43         private $mGroups = [];
  44         /**
  45          * @var array[]
  46          */
  47         private $mModules = [];
  48
  49         /**
  50          * Construct new module manager
  51          * @param ApiBase $parentModule Parent module instance will be used during instantiation
  52          */
  53         public function __construct( ApiBase $parentModule ) {
  54                 $this->mParent = $parentModule;
  55         }
  56
  57         /**
  58          * Add a list of modules to the manager. Each module is described
  59          * by a module spec.
  60          *
  61          * Each module spec is an associative array containing at least
  62          * the 'class' key for the module's class, and optionally a
  63          * 'factory' key for the factory function to use for the module.
  64          *
  65          * That factory function will be called with two parameters,
  66          * the parent module (an instance of ApiBase, usually ApiMain)
  67          * and the name the module was registered under. The return
  68          * value must be an instance of the class given in the 'class'
  69          * field.
  70          *
  71          * For backward compatibility, the module spec may also be a
  72          * simple string containing the module's class name. In that
  73          * case, the class' constructor will be called with the parent
  74          * module and module name as parameters, as described above.
  75          *
  76          * Examples for defining module specs:
  77          *
  78          * @code
  79          *  $modules['foo'] = 'ApiFoo';
  80          *  $modules['bar'] = [
  81          *      'class' => ApiBar::class,
  82          *      'factory' => function( $main, $name ) { ... }
  83          *  ];
  84          *  $modules['xyzzy'] = [
  85          *      'class' => ApiXyzzy::class,
  86          *      'factory' => [ XyzzyFactory::class, 'newApiModule' ]
  87          *  ];
  88          * @endcode
  89          *
  90          * @param array $modules A map of ModuleName => ModuleSpec; The ModuleSpec
  91          *        is either a string containing the module's class name, or an associative
  92          *        array (see above for details).
  93          * @param string $group Which group modules belong to (action,format,...)
  94          */
  95         public function addModules( array $modules, $group ) {
  96                 foreach ( $modules as $name => $moduleSpec ) {
  97                         if ( is_array( $moduleSpec ) ) {
  98                                 $class = $moduleSpec['class'];
  99                                 $factory = ( isset( $moduleSpec['factory'] ) ? $moduleSpec['factory'] : null );
 100                         } else {
 101                                 $class = $moduleSpec;
 102                                 $factory = null;
 103                         }
 104
 105                         $this->addModule( $name, $group, $class, $factory );
 106                 }
 107         }
 108
 109         /**
 110          * Add or overwrite a module in this ApiMain instance. Intended for use by extending
 111          * classes who wish to add their own modules to their lexicon or override the
 112          * behavior of inherent ones.
 113          *
 114          * @param string $name The identifier for this module.
 115          * @param string $group Name of the module group
 116          * @param string $class The class where this module is implemented.
 117          * @param callable|null $factory Callback for instantiating the module.
 118          *
 119          * @throws InvalidArgumentException
 120          */
 121         public function addModule( $name, $group, $class, $factory = null ) {
 122                 if ( !is_string( $name ) ) {
 123                         throw new InvalidArgumentException( '$name must be a string' );
 124                 }
 125
 126                 if ( !is_string( $group ) ) {
 127                         throw new InvalidArgumentException( '$group must be a string' );
 128                 }
 129
 130                 if ( !is_string( $class ) ) {
 131                         throw new InvalidArgumentException( '$class must be a string' );
 132                 }
 133
 134                 if ( $factory !== null && !is_callable( $factory ) ) {
 135                         throw new InvalidArgumentException( '$factory must be a callable (or null)' );
 136                 }
 137
 138                 $this->mGroups[$group] = null;
 139                 $this->mModules[$name] = [ $group, $class, $factory ];
 140         }
 141
 142         /**
 143          * Get module instance by name, or instantiate it if it does not exist
 144          *
 145          * @param string $moduleName Module name
 146          * @param string $group Optionally validate that the module is in a specific group
 147          * @param bool $ignoreCache If true, force-creates a new instance and does not cache it
 148          *
 149          * @return ApiBase|null The new module instance, or null if failed
 150          */
 151         public function getModule( $moduleName, $group = null, $ignoreCache = false ) {
 152                 if ( !isset( $this->mModules[$moduleName] ) ) {
 153                         return null;
 154                 }
 155
 156                 list( $moduleGroup, $moduleClass, $moduleFactory ) = $this->mModules[$moduleName];
 157
 158                 if ( $group !== null && $moduleGroup !== $group ) {
 159                         return null;
 160                 }
 161
 162                 if ( !$ignoreCache && isset( $this->mInstances[$moduleName] ) ) {
 163                         // already exists
 164                         return $this->mInstances[$moduleName];
 165                 } else {
 166                         // new instance
 167                         $instance = $this->instantiateModule( $moduleName, $moduleClass, $moduleFactory );
 168
 169                         if ( !$ignoreCache ) {
 170                                 // cache this instance in case it is needed later
 171                                 $this->mInstances[$moduleName] = $instance;
 172                         }
 173
 174                         return $instance;
 175                 }
 176         }
 177
 178         /**
 179          * Instantiate the module using the given class or factory function.
 180          *
 181          * @param string $name The identifier for this module.
 182          * @param string $class The class where this module is implemented.
 183          * @param callable|null $factory Callback for instantiating the module.
 184          *
 185          * @throws MWException
 186          * @return ApiBase
 187          */
 188         private function instantiateModule( $name, $class, $factory = null ) {
 189                 if ( $factory !== null ) {
 190                         // create instance from factory
 191                         $instance = call_user_func( $factory, $this->mParent, $name );
 192
 193                         if ( !$instance instanceof $class ) {
 194                                 throw new MWException(
 195                                         "The factory function for module $name did not return an instance of $class!"
 196                                 );
 197                         }
 198                 } else {
 199                         // create instance from class name
 200                         $instance = new $class( $this->mParent, $name );
 201                 }
 202
 203                 return $instance;
 204         }
 205
 206         /**
 207          * Get an array of modules in a specific group or all if no group is set.
 208          * @param string $group Optional group filter
 209          * @return array List of module names
 210          */
 211         public function getNames( $group = null ) {
 212                 if ( $group === null ) {
 213                         return array_keys( $this->mModules );
 214                 }
 215                 $result = [];
 216                 foreach ( $this->mModules as $name => $grpCls ) {
 217                         if ( $grpCls[0] === $group ) {
 218                                 $result[] = $name;
 219                         }
 220                 }
 221
 222                 return $result;
 223         }
 224
 225         /**
 226          * Create an array of (moduleName => moduleClass) for a specific group or for all.
 227          * @param string $group Name of the group to get or null for all
 228          * @return array Name=>class map
 229          */
 230         public function getNamesWithClasses( $group = null ) {
 231                 $result = [];
 232                 foreach ( $this->mModules as $name => $grpCls ) {
 233                         if ( $group === null || $grpCls[0] === $group ) {
 234                                 $result[$name] = $grpCls[1];
 235                         }
 236                 }
 237
 238                 return $result;
 239         }
 240
 241         /**
 242          * Returns the class name of the given module
 243          *
 244          * @param string $module Module name
 245          * @return string|bool class name or false if the module does not exist
 246          * @since 1.24
 247          */
 248         public function getClassName( $module ) {
 249                 if ( isset( $this->mModules[$module] ) ) {
 250                         return $this->mModules[$module][1];
 251                 }
 252
 253                 return false;
 254         }
 255
 256         /**
 257          * Returns true if the specific module is defined at all or in a specific group.
 258          * @param string $moduleName Module name
 259          * @param string $group Group name to check against, or null to check all groups,
 260          * @return bool True if defined
 261          */
 262         public function isDefined( $moduleName, $group = null ) {
 263                 if ( isset( $this->mModules[$moduleName] ) ) {
 264                         return $group === null || $this->mModules[$moduleName][0] === $group;
 265                 }
 266
 267                 return false;
 268         }
 269
 270         /**
 271          * Returns the group name for the given module
 272          * @param string $moduleName
 273          * @return string|null Group name or null if missing
 274          */
 275         public function getModuleGroup( $moduleName ) {
 276                 if ( isset( $this->mModules[$moduleName] ) ) {
 277                         return $this->mModules[$moduleName][0];
 278                 }
 279
 280                 return null;
 281         }
 282
 283         /**
 284          * Get a list of groups this manager contains.
 285          * @return array
 286          */
 287         public function getGroups() {
 288                 return array_keys( $this->mGroups );
 289         }
 290 }