root/trunk/common/mvblog_autoloader.php

<?php
/**
 * MvBlog -- An open source no-nosense blogtool
 *
 * Copyright (C) 2005-2008, Michiel van Baak
 * Michiel van Baak <mvanbaak@users.sourceforge.net>
 *
 * See http://dev.mvblog.org for more information on MvBlog.
 * That page also provides Bugtrackers, Filereleases etc.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 *
 * @package MvBlog
 * @author Ferry Boender
 * @version 2.0
 * @copyright 2005-2008 Ferry Boender
 */

/**
 * AutoLoader class handles auto loading of classes/objects.
 *
 * Example:
 * <code>
 * require_once("mvblog_AutoLoader.php");
 * 
 * $mvblog_AutoLoader = new mvblog_AutoLoader();
 *
 * // Add the directory in which the current file resides to the autoloader.
 * $pathInfo = pathinfo(__FILE__);
 * $mvblog_AutoLoader->registerPath($pathInfo["dirname"]);
 *
 * // Register the AutoLoader object as the autoloader.
 * function __autoload($className) {
 *   global $mvblog_AutoLoader; 
 *   $mvblog_AutoLoader->autoload($className);
 * }
 * </code>
 */
class mvblog_AutoLoader {
    const OPT_LOWERCASE = 1; 

    protected $paths = array();

    /**
     * Create a new mvblog_AutoLoader object. It will automatically parse
     * your PHP ini include_path for paths in which is should look
     * for objects. The default format it will look for is "CLASSNAME.php"
     * (case-sensitive). The current directory is usually included in
     * your include_path, so you won't have to add that. Add new
     * paths using ->registerPath($path, $format).
     *
     * @param array $paths (optional) An array containing paths and formats. Each element in $paths is an associative array with "path", "format" and "options" keys. I.e. new mvblog_AutoLoader(array(array("path"=>"/usr/share/lib/app", "format" => "class_%s.php", "options" => mvblog_AutoLoader::OPT_LOWERCASE)));
     */
    public function __construct($paths = null) {
        // Add paths in include_path ini setting of PHP.
        $phpIncludePath = ini_get("include_path");
        foreach (explode(':', $phpIncludePath) as $path) {
            $this->registerPath($path, "%s.php");
        }
        // Add user-defined paths
        if (isset($paths)) {
            foreach($paths as $path) {
                $realpath = realpath($path["path"]);
                $this->registerPath($realpath, $path["format"]);
            }
        }
    }

    /**
     * Add a new path to the list of paths where mvblog_AutoLoader will look for classes.
     * @param string $path The path. This will be automatically expanded to an absolute pathname (i.e. ../../foo will become /var/www/foo/, depending on your current path).
     * @param string $format (optional) The format of filenames to look for. %s will be expanded to the classname that needs to be loaded. Example: "class_%s.php".
     * @return bool false if path is not a dir or not set.
     */
    public function registerPath($path, $format = "%s.php", $options = 0) {
        $path = realpath($path);
        if ($path === false || !is_dir($path)) 
            return(false);

        $pathInfo = array("path" => $path, "format" => $format, "options" => $options);
        $this->paths[] = $pathInfo;

        return(true);
    }

    /**
     * The autoloader. It looks through all the paths and tries to find a file that contains the class to include.
     * This method should be called from an __autoload() function in your initializing code.
     * 
     * @param string className. The name of the class to load.
     */
    public function autoload($className) {
        foreach($this->paths as $path) {
            if ($path["options"] & mvblog_AutoLoader::OPT_LOWERCASE)
                $finalClassName = strtolower($className);
            else
                $finalClassName = $className;

            $filename = $path["path"] . '/' . sprintf($path["format"], $finalClassName);
            if (file_exists($filename)) {
                include_once($filename);
                return(true);
            }
        }
    }
}
?>