File Source for BitSingleton.php

<?php
/**
* Base class for all objects where only one object should be created
*
* @version $Header$
*
* Copyright (c) 2004 bitweaver.org
* All Rights Reserved. See below for details and a complete list of authors.
* Licensed under the GNU LESSER GENERAL PUBLIC LICENSE. See http://www.gnu.org/copyleft/lesser.html for details
*
* Virtual base class (as much as one can have such things in PHP) for all
* derived tikiwiki classes that require database access.
*
* created 2004/8/15
*
* @author spider <spider@steelsun.com>
* @package kernel
*/
/**
* required setup
*/
require_once( KERNEL_PKG_PATH . 'BitBase.php' );
/**
* @package kernel
*/
abstract class BitSingleton extends BitBase implements BitCacheable {
protected static $singletons = null;
function __construct() {
parent::__construct();
}
public static function loadSingleton( $pVarName = NULL ) {
$class = static::getClass();
$globalVarName = !empty( $pVarName ) ? $pVarName : 'g'.$class;
global $$globalVarName;
if( !($$globalVarName = static::loadFromCache( 'Singleton' )) ) {
$$globalVarName = new $class;
}
if(!isset(static::$singletons[$globalVarName])) {
static::$singletons[$globalVarName] = $$globalVarName;
global $gBitSmarty;
$gBitSmarty->assign_by_ref( $globalVarName, $$globalVarName );
}
return static::$singletons[$globalVarName];
}
public function getCacheKey() {
return 'Singleton';
}
public static function isCacheableClass() {
return true;
}
public function isCacheableObject() {
return true;
}
}
// I don't remember where I found this, but this is to allow php < 5.3 to use this method.
if (!function_exists('get_called_class')) {
function get_called_class($bt = false, $l = 1) {
if (!$bt)
$bt = debug_backtrace();
if (!isset($bt[$l]))
throw new Exception("Cannot find called class -> stack level too deep.");
if (!isset($bt[$l]['type'])) {
throw new Exception('type not set');
}
else
switch ($bt[$l]['type']) {
case '::':
$lines = file($bt[$l]['file']);
$i = 0;
$callerLine = '';
do {
$i++;
$callerLine = $lines[$bt[$l]['line'] - $i] . $callerLine;
} while (stripos($callerLine, $bt[$l]['function']) === false);
preg_match('/([a-zA-Z0-9\_]+)::' . $bt[$l]['function'] . '/', $callerLine, $matches);
if (!isset($matches[1])) {
// must be an edge case.
throw new Exception("Could not find caller class: originating method call is obscured.");
}
switch ($matches[1]) {
case 'self':
case 'parent':
return get_called_class($bt, $l + 1);
default:
return $matches[1];
}
// won't get here.
case '->': switch ($bt[$l]['function']) {
case '__get':
// edge case -> get class of calling object
if (!is_object($bt[$l]['object']))
throw new Exception("Edge case fail. __get called on non object.");
return get_class($bt[$l]['object']);
default: return $bt[$l]['class'];
}
default: throw new Exception("Unknown backtrace method type");
}
}
}

Source for file BitSingleton.php