1: <?php
  2: /**
  3:  * Publish-Subscribe system based on Phly_PubSub
  4:  * (http://weierophinney.net/matthew/archives/199-A-Simple-PHP-Publish-Subscribe-System.html)
  5:  *
  6:  * Copyright 2008-2011 Matthew Weier O'Phinney
  7:  * Copyright 2011-2012 Horde LLC (http://www.horde.org/)
  8:  *
  9:  * @category  Horde
 10:  * @package   PubSub
 11:  * @author    Matthew Weier O'Phinney <mweierophinney@gmail.com>
 12:  * @license   New BSD {@link http://www.opensource.org/licenses/bsd-license.php}
 13:  */
 14: 
 15: /**
 16:  * Publish-Subscribe provider
 17:  *
 18:  * Use Horde_PubSub_Provider when you want to create a per-instance plugin
 19:  * system for your objects.
 20:  *
 21:  * @category  Horde
 22:  * @package   PubSub
 23:  */
 24: class Horde_PubSub_Provider
 25: {
 26:     /**
 27:      * Subscribed topics and their handles
 28:      */
 29:     protected $_topics = array();
 30: 
 31:     /**
 32:      * Publish to all handlers for a given topic
 33:      *
 34:      * @param  string $topic
 35:      * @param  mixed $args All arguments besides the topic are passed as arguments to the handler
 36:      * @return void
 37:      */
 38:     public function publish($topic, $args = null)
 39:     {
 40:         if (empty($this->_topics[$topic])) {
 41:             return;
 42:         }
 43:         $args = func_get_args();
 44:         array_shift($args);
 45:         foreach ($this->_topics[$topic] as $handle) {
 46:             $handle->call($args);
 47:         }
 48:     }
 49: 
 50:     /**
 51:      * Subscribe to a topic
 52:      *
 53:      * @param  string $topic
 54:      * @param  string|object $context Function name, class name, or object instance
 55:      * @param  null|string $handler If $context is a class or object, the name of the method to call
 56:      * @return Horde_PubSub_Handle Pub-Sub handle (to allow later unsubscribe)
 57:      */
 58:     public function subscribe($topic, $context, $handler = null)
 59:     {
 60:         if (empty($this->_topics[$topic])) {
 61:             $this->_topics[$topic] = array();
 62:         }
 63:         $handle = new Horde_PubSub_Handle($topic, $context, $handler);
 64:         if (in_array($handle, $this->_topics[$topic])) {
 65:             $index = array_search($handle, $this->_topics[$topic]);
 66:             return $this->_topics[$topic][$index];
 67:         }
 68:         $this->_topics[$topic][] = $handle;
 69:         return $handle;
 70:     }
 71: 
 72:     /**
 73:      * Unsubscribe a handler from a topic
 74:      *
 75:      * @param  Horde_PubSub_Handle $handle
 76:      * @return bool Returns true if topic and handle found, and unsubscribed; returns false if either topic or handle not found
 77:      */
 78:     public function unsubscribe(Horde_PubSub_Handle $handle)
 79:     {
 80:         $topic = $handle->getTopic();
 81:         if (empty($this->_topics[$topic])) {
 82:             return false;
 83:         }
 84:         if (false === ($index = array_search($handle, $this->_topics[$topic]))) {
 85:             return false;
 86:         }
 87:         unset($this->_topics[$topic][$index]);
 88:         return true;
 89:     }
 90: 
 91:     /**
 92:      * Retrieve all registered topics
 93:      *
 94:      * @return array
 95:      */
 96:     public function getTopics()
 97:     {
 98:         return array_keys($this->_topics);
 99:     }
100: 
101:     /**
102:      * Retrieve all handlers for a given topic
103:      *
104:      * @param  string $topic
105:      * @return array Array of Horde_PubSub_Handle objects
106:      */
107:     public function getSubscribedHandles($topic)
108:     {
109:         if (empty($this->_topics[$topic])) {
110:             return array();
111:         }
112:         return $this->_topics[$topic];
113:     }
114: 
115:     /**
116:      * Clear all handlers for a given topic
117:      *
118:      * @param  string $topic
119:      * @return void
120:      */
121:     public function clearHandles($topic)
122:     {
123:         if (!empty($this->_topics[$topic])) {
124:             unset($this->_topics[$topic]);
125:         }
126:     }
127: }
128: