class.t3lib_autoloader.php

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<?php
/***************************************************************
 *  Copyright notice
 *
 *  (c) 2008-2011 Dmitry Dulepov <dmitry@typo3.org>
 *  All rights reserved
 *
 *  This script is part of the TYPO3 project. The TYPO3 project is
 *  free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  The GNU General Public License can be found at
 *  http://www.gnu.org/copyleft/gpl.html.
 *  A copy is found in the textfile GPL.txt and important notices to the license
 *  from the author is found in LICENSE.txt distributed with these scripts.
 *
 *
 *  This script 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 General Public License for more details.
 *
 *  This copyright notice MUST APPEAR in all copies of the script!
 ***************************************************************/
/**
 * Contains TYPO3 autoloader
 *
 * $Id: class.t3lib_autoloader.php 10121 2011-01-18 20:15:30Z ohader $
 *
 * @author  Dmitry Dulepov  <dmitry@typo3.org>
 * @author  Martin Kutschker <masi@typo3.org>
 * @author  Oliver Hader <oliver@typo3.org>
 * @author  Sebastian Kurfürst <sebastian@typo3.org>
 */

/**
 * This class contains TYPO3 autoloader for classes.
 * It handles:
 * - the core of TYPO3
 * - all extensions with an ext_autoload.php file
 */
class t3lib_autoloader {

    /**
     * Class name to file mapping. Key: class name. Value: fully qualified file name.
     *
     * @var array
     */
    protected static $classNameToFileMapping = array();

    /**
     * Associative array which sets for each extension which was attempted to load if it has an autoload configuration
     *
     * Key: extension key
     * Value: TRUE, if extension has an ext_autoload.php and this is already part of $classNameToFileMapping
     *        FALSE, if extension has no ext_autoload.php
     *
     * @var array
     */
    protected static $extensionHasAutoloadConfiguration = array();

    /**
     * The autoloader is static, thus we do not allow instances of this class.
     */
    private function __construct() {
    }

    /**
     * Installs TYPO3 autoloader, and loads the autoload registry for the core.
     *
     * @return  boolean true in case of success
     */
    static public function registerAutoloader() {
        self::loadCoreRegistry();
        self::$extensionHasAutoloadConfiguration = array();
        return spl_autoload_register('t3lib_autoloader::autoload');
    }

    /**
     * Uninstalls TYPO3 autoloader. This function is for the sake of completeness.
     * It is never called by the TYPO3 core.
     *
     * @return  boolean true in case of success
     */
    static public function unregisterAutoloader() {
        return spl_autoload_unregister('t3lib_autoloader::autoload');
    }

    /**
     * Autoload function for TYPO3.
     *
     * This method looks up class names in the registry
     * (which contains extensions and core files)
     *
     * @param   string  $className  Class name
     * @return  void
     */
    static public function autoload($className) {
        $classPath = false;

            // use core and extension registry
        $classPath = self::getClassPathByRegistryLookup($className);

        if ($classPath && file_exists($classPath)) {
            t3lib_div::requireFile($classPath);
        } else {
            try {
                    // Regular expression for a valid classname taken from
                    // http://www.php.net/manual/en/language.oop5.basic.php
                if (preg_match('/^[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*$/', $className)) {
                    spl_autoload($className);
                }
            } catch (LogicException $exception) {
            }
        }
    }

    /**
     * Load the core registry into $classNameToFileMapping, effectively overriding
     * the whole contents of $classNameToFileMapping.
     *
     * @return void
     */
    static protected function loadCoreRegistry() {
        self::$classNameToFileMapping = require(PATH_t3lib . 'core_autoload.php');
    }

    /**
     * Get the full path to a class by looking it up in the registry. If not found, returns NULL.
     *
     * @param   string  $className  Class name
     * @return  string  full name of the file where $className is declared, or NULL if no entry found in registry.
     */
    static protected function getClassPathByRegistryLookup($className) {
        $className = strtolower($className);
        if (!array_key_exists($className, self::$classNameToFileMapping)) {
            self::attemptToLoadRegistryForGivenClassName($className);
        }
        if (array_key_exists($className, self::$classNameToFileMapping)) {
            return self::$classNameToFileMapping[$className];
        } else {
            return NULL;
        }
    }

    /**
     * Try to load the entries for a given class name into the registry.
     *
     * First, figures out the extension the class belongs to.
     * Then, tries to load the ext_autoload.php file inside the extension directory, and adds its contents to the $classNameToFileMapping.
     *
     * @param   string  $className  Class Name
     */
    static protected function attemptToLoadRegistryForGivenClassName($className) {
        $classNameParts = explode('_', $className);
        $extensionPrefix = array_shift($classNameParts) . '_' . array_shift($classNameParts);
        $extensionKey = t3lib_extMgm::getExtensionKeyByPrefix($extensionPrefix);

        if (!$extensionKey || array_key_exists($extensionKey, self::$extensionHasAutoloadConfiguration)) {
                // extension key could not be determined or we already tried to load the extension's autoload configuration
            return;
        }
        $possibleAutoloadConfigurationFileName = t3lib_extMgm::extPath($extensionKey) . 'ext_autoload.php';
        if (file_exists($possibleAutoloadConfigurationFileName)) {
            self::$extensionHasAutoloadConfiguration[$extensionKey] = TRUE;
            $extensionClassNameToFileMapping = require($possibleAutoloadConfigurationFileName);
            self::$classNameToFileMapping = array_merge($extensionClassNameToFileMapping, self::$classNameToFileMapping);
        } else {
            self::$extensionHasAutoloadConfiguration[$extensionKey] = FALSE;
        }
    }
}
?>