1: <?php
2: /**
3: * Helpers collection is used as a registry for loaded helpers and handles loading
4: * and constructing helper class objects.
5: *
6: * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
7: * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
8: *
9: * Licensed under The MIT License
10: * For full copyright and license information, please see the LICENSE.txt
11: * Redistributions of files must retain the above copyright notice.
12: *
13: * @copyright Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
14: * @link http://cakephp.org CakePHP(tm) Project
15: * @package Cake.View
16: * @since CakePHP(tm) v 2.0
17: * @license http://www.opensource.org/licenses/mit-license.php MIT License
18: */
19:
20: App::uses('ObjectCollection', 'Utility');
21: App::uses('CakeEventListener', 'Event');
22:
23: /**
24: * Helpers collection is used as a registry for loaded helpers and handles loading
25: * and constructing helper class objects.
26: *
27: * @package Cake.View
28: */
29: class HelperCollection extends ObjectCollection implements CakeEventListener {
30:
31: /**
32: * View object to use when making helpers.
33: *
34: * @var View
35: */
36: protected $_View;
37:
38: /**
39: * Constructor
40: *
41: * @param View $view View instance.
42: */
43: public function __construct(View $view) {
44: $this->_View = $view;
45: }
46:
47: /**
48: * Tries to lazy load a helper based on its name, if it cannot be found
49: * in the application folder, then it tries looking under the current plugin
50: * if any
51: *
52: * @param string $helper The helper name to be loaded
53: * @return bool whether the helper could be loaded or not
54: * @throws MissingHelperException When a helper could not be found.
55: * App helpers are searched, and then plugin helpers.
56: */
57: public function __isset($helper) {
58: if (parent::__isset($helper)) {
59: return true;
60: }
61:
62: try {
63: $this->load($helper);
64: } catch (MissingHelperException $exception) {
65: if ($this->_View->plugin) {
66: $this->load($this->_View->plugin . '.' . $helper);
67: return true;
68: }
69: }
70:
71: if (!empty($exception)) {
72: throw $exception;
73: }
74:
75: return true;
76: }
77:
78: /**
79: * Provide public read access to the loaded objects
80: *
81: * @param string $name Name of property to read
82: * @return mixed
83: */
84: public function __get($name) {
85: if ($result = parent::__get($name)) {
86: return $result;
87: }
88: if ($this->__isset($name)) {
89: return $this->_loaded[$name];
90: }
91: return null;
92: }
93:
94: /**
95: * Loads/constructs a helper. Will return the instance in the registry if it already exists.
96: * By setting `$enable` to false you can disable callbacks for a helper. Alternatively you
97: * can set `$settings['enabled'] = false` to disable callbacks. This alias is provided so that when
98: * declaring $helpers arrays you can disable callbacks on helpers.
99: *
100: * You can alias your helper as an existing helper by setting the 'className' key, i.e.,
101: * {{{
102: * public $helpers = array(
103: * 'Html' => array(
104: * 'className' => 'AliasedHtml'
105: * );
106: * );
107: * }}}
108: * All calls to the `Html` helper would use `AliasedHtml` instead.
109: *
110: * @param string $helper Helper name to load
111: * @param array $settings Settings for the helper.
112: * @return Helper A helper object, Either the existing loaded helper or a new one.
113: * @throws MissingHelperException when the helper could not be found
114: */
115: public function load($helper, $settings = array()) {
116: if (isset($settings['className'])) {
117: $alias = $helper;
118: $helper = $settings['className'];
119: }
120: list($plugin, $name) = pluginSplit($helper, true);
121: if (!isset($alias)) {
122: $alias = $name;
123: }
124:
125: if (isset($this->_loaded[$alias])) {
126: return $this->_loaded[$alias];
127: }
128: $helperClass = $name . 'Helper';
129: App::uses($helperClass, $plugin . 'View/Helper');
130: if (!class_exists($helperClass)) {
131: throw new MissingHelperException(array(
132: 'class' => $helperClass,
133: 'plugin' => substr($plugin, 0, -1)
134: ));
135: }
136: $this->_loaded[$alias] = new $helperClass($this->_View, $settings);
137:
138: $vars = array('request', 'theme', 'plugin');
139: foreach ($vars as $var) {
140: $this->_loaded[$alias]->{$var} = $this->_View->{$var};
141: }
142: $enable = isset($settings['enabled']) ? $settings['enabled'] : true;
143: if ($enable) {
144: $this->enable($alias);
145: }
146: return $this->_loaded[$alias];
147: }
148:
149: /**
150: * Returns a list of all events that will fire in the View during it's lifecycle.
151: *
152: * @return array
153: */
154: public function implementedEvents() {
155: return array(
156: 'View.beforeRenderFile' => 'trigger',
157: 'View.afterRenderFile' => 'trigger',
158: 'View.beforeRender' => 'trigger',
159: 'View.afterRender' => 'trigger',
160: 'View.beforeLayout' => 'trigger',
161: 'View.afterLayout' => 'trigger'
162: );
163: }
164:
165: /**
166: * Trigger a callback method on every object in the collection.
167: * Used to trigger methods on objects in the collection. Will fire the methods in the
168: * order they were attached.
169: *
170: * ### Options
171: *
172: * - `breakOn` Set to the value or values you want the callback propagation to stop on.
173: * Can either be a scalar value, or an array of values to break on. Defaults to `false`.
174: *
175: * - `break` Set to true to enabled breaking. When a trigger is broken, the last returned value
176: * will be returned. If used in combination with `collectReturn` the collected results will be returned.
177: * Defaults to `false`.
178: *
179: * - `collectReturn` Set to true to collect the return of each object into an array.
180: * This array of return values will be returned from the trigger() call. Defaults to `false`.
181: *
182: * - `modParams` Allows each object the callback gets called on to modify the parameters to the next object.
183: * Setting modParams to an integer value will allow you to modify the parameter with that index.
184: * Any non-null value will modify the parameter index indicated.
185: * Defaults to false.
186: *
187: * @param string|CakeEvent $callback Method to fire on all the objects. Its assumed all the objects implement
188: * the method you are calling. If an instance of CakeEvent is provided, then then Event name will parsed to
189: * get the callback name. This is done by getting the last word after any dot in the event name
190: * (eg. `Model.afterSave` event will trigger the `afterSave` callback)
191: * @param array $params Array of parameters for the triggered callback.
192: * @param array $options Array of options.
193: * @return mixed Either the last result or all results if collectReturn is on.
194: * @throws CakeException when modParams is used with an index that does not exist.
195: */
196: public function trigger($callback, $params = array(), $options = array()) {
197: if ($callback instanceof CakeEvent) {
198: $callback->omitSubject = true;
199: }
200: return parent::trigger($callback, $params, $options);
201: }
202:
203: }
204: