/system/libraries/Config.php

<?php if (!defined('TL_ROOT')) die('You cannot access this file directly!');

/**
 * Contao Open Source CMS
 * Copyright (C) 2005-2011 Leo Feyer
 *
 * Formerly known as TYPOlight Open Source CMS.
 *
 * This program is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program. If not, please visit the Free
 * Software Foundation website at <http://www.gnu.org/licenses/>.
 *
 * PHP version 5
 * @copyright  Leo Feyer 2005-2011
 * @author     Leo Feyer <http://www.contao.org>
 * @package    System
 * @license    LGPL
 * @filesource
 */


/**
 * Class Config
 *
 * Provide methods to manage configuration files.
 * @copyright  Leo Feyer 2005-2011
 * @author     Leo Feyer <http://www.contao.org>
 * @package    Library
 */
class Config
{

	/**
	 * Current object instance (Singleton)
	 * @var object
	 */
	protected static $objInstance;

	/**
	 * Files object
	 * @var object
	 */
	protected $Files;

	/**
	 * Top content
	 * @var string
	 */
	protected $strTop = '';

	/**
	 * Bottom content
	 * @var string
	 */
	protected $strBottom = '';

	/**
	 * Modified
	 * @var boolean
	 */
	protected $blnIsModified = false;

	/**
	 * Data array
	 * @var array
	 */
	protected $arrData = array();

	/**
	 * Cache array
	 * @var array
	 */
	protected $arrCache = array();


	/**
	 * Load all configuration files
	 */
	protected function __construct()
	{
		include(TL_ROOT . '/system/config/config.php');
		include(TL_ROOT . '/system/config/localconfig.php');

		// Get module configuration files
		foreach ($this->getActiveModules() as $strModule)
		{
			$strFile = sprintf('%s/system/modules/%s/config/config.php', TL_ROOT, $strModule);
			@include($strFile);
		}

		include(TL_ROOT . '/system/config/localconfig.php');

		// Read the local configuration file
		$strMode = 'top';
		$resFile = fopen(TL_ROOT . '/system/config/localconfig.php', 'rb');

		while (!feof($resFile))
		{
			$strLine = fgets($resFile);
			$strTrim = trim($strLine);

			if ($strTrim == '?>')
			{
				continue;
			}

			if ($strTrim == '### INSTALL SCRIPT START ###')
			{
				$strMode = 'data';
				continue;
			}

			if ($strTrim == '### INSTALL SCRIPT STOP ###')
			{
				$strMode = 'bottom';
				continue;
			}
			
			if ($strMode == 'top')
			{
				$this->strTop .= $strLine;
			}
			elseif ($strMode == 'bottom')
			{
				$this->strBottom .= $strLine;
			}
			elseif ($strTrim != '')
			{
				$arrChunks = array_map('trim', explode('=', $strLine, 2));
				$this->arrData[$arrChunks[0]] = $arrChunks[1];
			}
		}

		fclose($resFile);
	}
	

	/**
	 * Save the local configuration
	 */
	public function __destruct()
	{
		if (!$this->blnIsModified)
		{
			return;
		}

		$strFile  = trim($this->strTop) . "\n\n";
		$strFile .= "### INSTALL SCRIPT START ###\n";

		foreach ($this->arrData as $k=>$v)
		{
			$strFile .= "$k = $v\n";
		}

		$strFile .= "### INSTALL SCRIPT STOP ###\n\n";
		$this->strBottom = trim($this->strBottom);

		if ($this->strBottom != '')
		{
			$strFile .= $this->strBottom . "\n\n";
		}

		$strFile .= '?>';

		$objFile = new File('system/config/localconfig.php');
		$objFile->write($strFile);
		$objFile->close();
	}


	/**
	 * Prevent cloning of the object (Singleton)
	 */
	final private function __clone() {}


	/**
	 * Return the current object instance (Singleton)
	 * @return object
	 */
	public static function getInstance()
	{
		if (!is_object(self::$objInstance))
		{
			self::$objInstance = new Config();
		}

		return self::$objInstance;
	}


	/**
	 * Return all active modules (starting with "backend" and "frontend") as array
	 * @param boolean
	 * @return array
	 */
	public function getActiveModules($blnNoCache=false)
	{
		if (!$blnNoCache && isset($this->arrCache['activeModules']))
		{
			return (array) $this->arrCache['activeModules']; // (array) = PHP 5.1.2 fix
		}

		$arrActiveModules = array('backend', 'frontend');
		$arrAllModules = scan(TL_ROOT . '/system/modules');

		$arrInactiveModules = deserialize($GLOBALS['TL_CONFIG']['inactiveModules']);
		$blnCheckInactiveModules = is_array($arrInactiveModules);

		foreach ($arrAllModules as $strModule)
		{
			if (substr($strModule, 0, 1) == '.')
			{
				continue;
			}

			if ($strModule == 'backend' || $strModule == 'frontend' || !is_dir(TL_ROOT . '/system/modules/' . $strModule))
			{
				continue;
			}

			if ($blnCheckInactiveModules && in_array($strModule, $arrInactiveModules))
			{
				continue;
			}

			$arrActiveModules[] = $strModule;
		}

		$this->arrCache['activeModules'] = $arrActiveModules;
		return $this->arrCache['activeModules'];
	}


	/**
	 * Add a configuration variable to the local configuration file
	 * @param string
	 * @param mixed
	 */
	public function add($strKey, $varValue)
	{
		$this->blnIsModified = true;
		$this->arrData[$strKey] = $this->escape($varValue) . ';';
	}


	/**
	 * Alias for Config::add()
	 * @param string
	 * @param mixed
	 */
	public function update($strKey, $varValue)
	{
		$this->add($strKey, $varValue);
	}


	/**
	 * Delete a configuration variable from the local configuration file
	 * @param string
	 * @param mixed
	 */
	public function delete($strKey)
	{
		$this->blnIsModified = true;
		unset($this->arrData[$strKey]);
	}


	/**
	 * Escape a parameter depending on its type and return it
	 * @param mixed
	 * @return mixed
	 */
	protected function escape($varValue)
	{
		if (is_numeric($varValue) && !preg_match('/e|^00+/', $varValue))
		{
			return $varValue;
		}

		if (is_bool($varValue))
		{
			return $varValue ? 'true' : 'false';
		}

		if ($varValue == 'true')
		{
			return 'true';
		}

		if ($varValue == 'false')
		{
			return 'false';
		}

		$varValue = preg_replace('/[\n\r\t]+/i', ' ', str_replace("'", "\\'", $varValue));
		$varValue = "'" . preg_replace('/ {2,}/i', ' ', $varValue) . "'";

		return $varValue;
	}
}

?>