includes/api/ApiModuleManager.php

   1 <?php
   2 /**
   3  *
   4  *
   5  * Created on Dec 27, 2012
   6  *
   7  * Copyright © 2012 Yuri Astrakhan "<Firstname><Lastname>@gmail.com"
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  22  * http://www.gnu.org/copyleft/gpl.html
  23  *
  24  * @file
  25  * @since 1.21
  26  */
  27
  28 /**
  29  * This class holds a list of modules and handles instantiation
  30  *
  31  * @since 1.21
  32  * @ingroup API
  33  */
  34 class ApiModuleManager extends ContextSource {
  35
  36         /**
  37          * @var ApiBase
  38          */
  39         private $mParent;
  40         /**
  41          * @var ApiBase[]
  42          */
  43         private $mInstances = array();
  44         /**
  45          * @var null[]
  46          */
  47         private $mGroups = array();
  48         /**
  49          * @var array[]
  50          */
  51         private $mModules = array();
  52
  53         /**
  54          * Construct new module manager
  55          * @param ApiBase $parentModule Parent module instance will be used during instantiation
  56          */
  57         public function __construct( ApiBase $parentModule ) {
  58                 $this->mParent = $parentModule;
  59         }
  60
  61         /**
  62          * Add a list of modules to the manager. Each module is described
  63          * by a module spec.
  64          *
  65          * Each module spec is an associative array containing at least
  66          * the 'class' key for the module's class, and optionally a
  67          * 'factory' key for the factory function to use for the module.
  68          *
  69          * That factory function will be called with two parameters,
  70          * the parent module (an instance of ApiBase, usually ApiMain)
  71          * and the name the module was registered under. The return
  72          * value must be an instance of the class given in the 'class'
  73          * field.
  74          *
  75          * For backward compatibility, the module spec may also be a
  76          * simple string containing the module's class name. In that
  77          * case, the class' constructor will be called with the parent
  78          * module and module name as parameters, as described above.
  79          *
  80          * Examples for defining module specs:
  81          *
  82          * @code
  83          *  $modules['foo'] = 'ApiFoo';
  84          *  $modules['bar'] = array(
  85          *      'class' => 'ApiBar',
  86          *      'factory' => function( $main, $name ) { ... }
  87          *  );
  88          *  $modules['xyzzy'] = array(
  89          *      'class' => 'ApiXyzzy',
  90          *      'factory' => array( 'XyzzyFactory', 'newApiModule' )
  91          *  );
  92          * @endcode
  93          *
  94          * @param array $modules A map of ModuleName => ModuleSpec; The ModuleSpec
  95          *        is either a string containing the module's class name, or an associative
  96          *        array (see above for details).
  97          * @param string $group Which group modules belong to (action,format,...)
  98          */
  99         public function addModules( array $modules, $group ) {
 100
 101                 foreach ( $modules as $name => $moduleSpec ) {
 102                         if ( is_array( $moduleSpec ) ) {
 103                                 $class = $moduleSpec['class'];
 104                                 $factory = ( isset( $moduleSpec['factory'] ) ? $moduleSpec['factory'] : null );
 105                         } else {
 106                                 $class = $moduleSpec;
 107                                 $factory = null;
 108                         }
 109
 110                         $this->addModule( $name, $group, $class, $factory );
 111                 }
 112         }
 113
 114         /**
 115          * Add or overwrite a module in this ApiMain instance. Intended for use by extending
 116          * classes who wish to add their own modules to their lexicon or override the
 117          * behavior of inherent ones.
 118          *
 119          * @param string $name The identifier for this module.
 120          * @param string $group Name of the module group
 121          * @param string $class The class where this module is implemented.
 122          * @param callable|null $factory Callback for instantiating the module.
 123          *
 124          * @throws InvalidArgumentException
 125          */
 126         public function addModule( $name, $group, $class, $factory = null ) {
 127                 if ( !is_string( $name ) ) {
 128                         throw new InvalidArgumentException( '$name must be a string' );
 129                 }
 130
 131                 if ( !is_string( $group ) ) {
 132                         throw new InvalidArgumentException( '$group must be a string' );
 133                 }
 134
 135                 if ( !is_string( $class ) ) {
 136                         throw new InvalidArgumentException( '$class must be a string' );
 137                 }
 138
 139                 if ( $factory !== null && !is_callable( $factory ) ) {
 140                         throw new InvalidArgumentException( '$factory must be a callable (or null)' );
 141                 }
 142
 143                 $this->mGroups[$group] = null;
 144                 $this->mModules[$name] = array( $group, $class, $factory );
 145         }
 146
 147         /**
 148          * Get module instance by name, or instantiate it if it does not exist
 149          *
 150          * @param string $moduleName Module name
 151          * @param string $group Optionally validate that the module is in a specific group
 152          * @param bool $ignoreCache If true, force-creates a new instance and does not cache it
 153          *
 154          * @return ApiBase|null The new module instance, or null if failed
 155          */
 156         public function getModule( $moduleName, $group = null, $ignoreCache = false ) {
 157                 if ( !isset( $this->mModules[$moduleName] ) ) {
 158                         return null;
 159                 }
 160
 161                 list( $moduleGroup, $moduleClass, $moduleFactory ) = $this->mModules[$moduleName];
 162
 163                 if ( $group !== null && $moduleGroup !== $group ) {
 164                         return null;
 165                 }
 166
 167                 if ( !$ignoreCache && isset( $this->mInstances[$moduleName] ) ) {
 168                         // already exists
 169                         return $this->mInstances[$moduleName];
 170                 } else {
 171                         // new instance
 172                         $instance = $this->instantiateModule( $moduleName, $moduleClass, $moduleFactory );
 173
 174                         if ( !$ignoreCache ) {
 175                                 // cache this instance in case it is needed later
 176                                 $this->mInstances[$moduleName] = $instance;
 177                         }
 178
 179                         return $instance;
 180                 }
 181         }
 182
 183         /**
 184          * Instantiate the module using the given class or factory function.
 185          *
 186          * @param string $name The identifier for this module.
 187          * @param string $class The class where this module is implemented.
 188          * @param callable|null $factory Callback for instantiating the module.
 189          *
 190          * @throws MWException
 191          * @return ApiBase
 192          */
 193         private function instantiateModule( $name, $class, $factory = null ) {
 194                 if ( $factory !== null ) {
 195                         // create instance from factory
 196                         $instance = call_user_func( $factory, $this->mParent, $name );
 197
 198                         if ( !$instance instanceof $class ) {
 199                                 throw new MWException(
 200                                         "The factory function for module $name did not return an instance of $class!"
 201                                 );
 202                         }
 203                 } else {
 204                         // create instance from class name
 205                         $instance = new $class( $this->mParent, $name );
 206                 }
 207
 208                 return $instance;
 209         }
 210
 211         /**
 212          * Get an array of modules in a specific group or all if no group is set.
 213          * @param string $group Optional group filter
 214          * @return array List of module names
 215          */
 216         public function getNames( $group = null ) {
 217                 if ( $group === null ) {
 218                         return array_keys( $this->mModules );
 219                 }
 220                 $result = array();
 221                 foreach ( $this->mModules as $name => $grpCls ) {
 222                         if ( $grpCls[0] === $group ) {
 223                                 $result[] = $name;
 224                         }
 225                 }
 226
 227                 return $result;
 228         }
 229
 230         /**
 231          * Create an array of (moduleName => moduleClass) for a specific group or for all.
 232          * @param string $group Name of the group to get or null for all
 233          * @return array Name=>class map
 234          */
 235         public function getNamesWithClasses( $group = null ) {
 236                 $result = array();
 237                 foreach ( $this->mModules as $name => $grpCls ) {
 238                         if ( $group === null || $grpCls[0] === $group ) {
 239                                 $result[$name] = $grpCls[1];
 240                         }
 241                 }
 242
 243                 return $result;
 244         }
 245
 246         /**
 247          * Returns the class name of the given module
 248          *
 249          * @param string $module Module name
 250          * @return string|bool class name or false if the module does not exist
 251          * @since 1.24
 252          */
 253         public function getClassName( $module ) {
 254                 if ( isset( $this->mModules[$module] ) ) {
 255                         return $this->mModules[$module][1];
 256                 }
 257
 258                 return false;
 259         }
 260
 261         /**
 262          * Returns true if the specific module is defined at all or in a specific group.
 263          * @param string $moduleName Module name
 264          * @param string $group Group name to check against, or null to check all groups,
 265          * @return bool True if defined
 266          */
 267         public function isDefined( $moduleName, $group = null ) {
 268                 if ( isset( $this->mModules[$moduleName] ) ) {
 269                         return $group === null || $this->mModules[$moduleName][0] === $group;
 270                 }
 271
 272                 return false;
 273         }
 274
 275         /**
 276          * Returns the group name for the given module
 277          * @param string $moduleName
 278          * @return string|null Group name or null if missing
 279          */
 280         public function getModuleGroup( $moduleName ) {
 281                 if ( isset( $this->mModules[$moduleName] ) ) {
 282                         return $this->mModules[$moduleName][0];
 283                 }
 284
 285                 return null;
 286         }
 287
 288         /**
 289          * Get a list of groups this manager contains.
 290          * @return array
 291          */
 292         public function getGroups() {
 293                 return array_keys( $this->mGroups );
 294         }
 295 }