Differential D5873 Diff 13013 externals/JAXL/core/jaxl_event.php

Changeset View

Standalone View

externals/JAXL/core/jaxl_event.php

This file was added.

				<?php
				/**
				* Jaxl (Jabber XMPP Library)
				*
				* Copyright (c) 2009-2012, Abhinav Singh <me@abhinavsingh.com>.
				* All rights reserved.
				*
				* Redistribution and use in source and binary forms, with or without
				* modification, are permitted provided that the following conditions
				* are met:
				*
				* * Redistributions of source code must retain the above copyright
				* notice, this list of conditions and the following disclaimer.
				*
				* * Redistributions in binary form must reproduce the above copyright
				* notice, this list of conditions and the following disclaimer in
				* the documentation and/or other materials provided with the
				* distribution.
				*
				* * Neither the name of Abhinav Singh nor the names of his
				* contributors may be used to endorse or promote products derived
				* from this software without specific prior written permission.
				*
				* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
				* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
				* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
				* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
				* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
				* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
				* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
				* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
				* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRIC
				* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
				* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
				* POSSIBILITY OF SUCH DAMAGE.
				*
				*/

				/**
				* following kind of events are possible:
				* 1) hook i.e. if a callback for such an event is registered, calling function is responsible for the workflow from their on
				* 2) filter i.e. calling function will manipulate passed arguments and modified arguments will be passed to next chain of filter
				*
				* As a rule of thumb, only 1 hook can be registered for an event, while more than 1 filter is allowed for an event
				* hook and filter both cannot be applied on an event
				*
				* @author abhinavsingh
				*
				*/
				class JAXLEvent {

				protected $common = array();
				public $reg = array();

				public function __construct($common) {
				$this->common = $common;
				}

				public function __destruct() {

				}

				// add callback on a event
				// returns a reference to be used while deleting callback
				// callback'd method must return TRUE to be persistent
				// if none returned or FALSE, callback will be removed automatically
				public function add($ev, $cb, $pri) {
				if(!isset($this->reg[$ev]))
				$this->reg[$ev] = array();

				$ref = sizeof($this->reg[$ev]);
				$this->reg[$ev][] = array($pri, $cb);
				return $ev."-".$ref;
				}

				// emit event to notify registered callbacks
				// is a pqueue required here for performance enhancement
				// in case we have too many cbs on a specific event?
				public function emit($ev, $data=array()) {
				$data = array_merge($this->common, $data);
				$cbs = array();

				if(!isset($this->reg[$ev])) return $data;

				foreach($this->reg[$ev] as $cb) {
				if(!isset($cbs[$cb[0]]))
				$cbs[$cb[0]] = array();
				$cbs[$cb[0]][] = $cb[1];
				}

				foreach($cbs as $pri => $cb) {
				foreach($cb as $c) {
				$ret = call_user_func_array($c, $data);
				// this line is for fixing situation where callback function doesn't return an array type
				// in such cases next call of call_user_func_array will report error since $data is not an array type as expected
				// things will change in future, atleast put the callback inside a try/catch block
				// here we only check if there was a return, if yes we update $data with return value
				// this is bad design, need more thoughts, should work as of now
				if($ret) $data = $ret;
				}
				}

				unset($cbs);
				return $data;
				}

				// remove previous registered callback
				public function del($ref) {
				$ref = explode("-", $ref);
				unset($this->reg[$ref[0]][$ref[1]]);
				}

				public function exists($ev) {
				$ret = isset($this->reg[$ev]);
				//_debug("event ".$ev." callback ".($ret ? "exists" : "do not exists"));
				return $ret;
				}

				}

				?>