1: <?php
  2: /**
  3:  * CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
  4:  * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
  5:  *
  6:  * Licensed under The MIT License
  7:  * For full copyright and license information, please see the LICENSE.txt
  8:  * Redistributions of files must retain the above copyright notice.
  9:  *
 10:  * @copyright     Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
 11:  * @link          https://cakephp.org CakePHP(tm) Project
 12:  * @since         2.0.0
 13:  * @license       https://opensource.org/licenses/mit-license.php MIT License
 14:  */
 15: namespace Cake\View;
 16: 
 17: use Cake\Core\App;
 18: use Cake\Core\ObjectRegistry;
 19: use Cake\Event\EventDispatcherInterface;
 20: use Cake\Event\EventDispatcherTrait;
 21: use Cake\View\Exception\MissingHelperException;
 22: 
 23: /**
 24:  * HelperRegistry is used as a registry for loaded helpers and handles loading
 25:  * and constructing helper class objects.
 26:  */
 27: class HelperRegistry extends ObjectRegistry implements EventDispatcherInterface
 28: {
 29: 
 30:     use EventDispatcherTrait;
 31: 
 32:     /**
 33:      * View object to use when making helpers.
 34:      *
 35:      * @var \Cake\View\View
 36:      */
 37:     protected $_View;
 38: 
 39:     /**
 40:      * Constructor
 41:      *
 42:      * @param \Cake\View\View $view View object.
 43:      */
 44:     public function __construct(View $view)
 45:     {
 46:         $this->_View = $view;
 47:         $this->setEventManager($view->getEventManager());
 48:     }
 49: 
 50:     /**
 51:      * Tries to lazy load a helper based on its name, if it cannot be found
 52:      * in the application folder, then it tries looking under the current plugin
 53:      * if any
 54:      *
 55:      * @param string $helper The helper name to be loaded
 56:      * @return bool whether the helper could be loaded or not
 57:      * @throws \Cake\View\Exception\MissingHelperException When a helper could not be found.
 58:      *    App helpers are searched, and then plugin helpers.
 59:      */
 60:     public function __isset($helper)
 61:     {
 62:         if (isset($this->_loaded[$helper])) {
 63:             return true;
 64:         }
 65: 
 66:         try {
 67:             $this->load($helper);
 68:         } catch (Exception\MissingHelperException $exception) {
 69:             if ($this->_View->getPlugin()) {
 70:                 $this->load($this->_View->getPlugin() . '.' . $helper);
 71: 
 72:                 return true;
 73:             }
 74:         }
 75: 
 76:         if (!empty($exception)) {
 77:             throw $exception;
 78:         }
 79: 
 80:         return true;
 81:     }
 82: 
 83:     /**
 84:      * Provide public read access to the loaded objects
 85:      *
 86:      * @param string $name Name of property to read
 87:      * @return mixed
 88:      */
 89:     public function __get($name)
 90:     {
 91:         if (isset($this->_loaded[$name])) {
 92:             return $this->_loaded[$name];
 93:         }
 94:         if (isset($this->{$name})) {
 95:             return $this->_loaded[$name];
 96:         }
 97: 
 98:         return null;
 99:     }
100: 
101:     /**
102:      * Resolve a helper classname.
103:      *
104:      * Part of the template method for Cake\Core\ObjectRegistry::load()
105:      *
106:      * @param string $class Partial classname to resolve.
107:      * @return string|false Either the correct classname or false.
108:      */
109:     protected function _resolveClassName($class)
110:     {
111:         return App::className($class, 'View/Helper', 'Helper');
112:     }
113: 
114:     /**
115:      * Throws an exception when a helper is missing.
116:      *
117:      * Part of the template method for Cake\Core\ObjectRegistry::load()
118:      * and Cake\Core\ObjectRegistry::unload()
119:      *
120:      * @param string $class The classname that is missing.
121:      * @param string $plugin The plugin the helper is missing in.
122:      * @return void
123:      * @throws \Cake\View\Exception\MissingHelperException
124:      */
125:     protected function _throwMissingClassError($class, $plugin)
126:     {
127:         throw new MissingHelperException([
128:             'class' => $class . 'Helper',
129:             'plugin' => $plugin
130:         ]);
131:     }
132: 
133:     /**
134:      * Create the helper instance.
135:      *
136:      * Part of the template method for Cake\Core\ObjectRegistry::load()
137:      * Enabled helpers will be registered with the event manager.
138:      *
139:      * @param string $class The class to create.
140:      * @param string $alias The alias of the loaded helper.
141:      * @param array $settings An array of settings to use for the helper.
142:      * @return \Cake\View\Helper The constructed helper class.
143:      */
144:     protected function _create($class, $alias, $settings)
145:     {
146:         $instance = new $class($this->_View, $settings);
147: 
148:         $enable = isset($settings['enabled']) ? $settings['enabled'] : true;
149:         if ($enable) {
150:             $this->getEventManager()->on($instance);
151:         }
152: 
153:         return $instance;
154:     }
155: }
156: