php/external/Zend/Loader.php

<?php

/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Loader
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Loader.php 8906 2008-03-19 19:15:30Z darby $
 */

/**
 * Static methods for loading classes and files.
 *
 * @category   Zend
 * @package    Zend_Loader
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Loader {

  /**
   * Loads a class from a PHP file.  The filename must be formatted
   * as "$class.php".
   *
   * If $dirs is a string or an array, it will search the directories
   * in the order supplied, and attempt to load the first matching file.
   *
   * If $dirs is null, it will split the class name at underscores to
   * generate a path hierarchy (e.g., "Zend_Example_Class" will map
   * to "Zend/Example/Class.php").
   *
   * If the file was not found in the $dirs, or if no $dirs were specified,
   * it will attempt to load it from PHP's include_path.
   *
   * @param string $class      - The full class name of a Zend component.
   * @param string|array $dirs - OPTIONAL Either a path or an array of paths
   *                             to search.
   * @return void
   * @throws Zend_Exception
   */
  public static function loadClass($class, $dirs = null) {
    if (class_exists($class, false) || interface_exists($class, false)) {
      return;
    }
    
    if ((null !== $dirs) && ! is_string($dirs) && ! is_array($dirs)) {
      require_once 'external/Zend/Exception.php';
      throw new Zend_Exception('Directory argument must be a string or an array');
    }
    
    // autodiscover the path from the class name
    $file = str_replace('_', DIRECTORY_SEPARATOR, $class) . '.php';
    if (! empty($dirs)) {
      // use the autodiscovered path
      $dirPath = dirname($file);
      if (is_string($dirs)) {
        $dirs = explode(PATH_SEPARATOR, $dirs);
      }
      foreach ($dirs as $key => $dir) {
        if ($dir == '.') {
          $dirs[$key] = $dirPath;
        } else {
          $dir = rtrim($dir, '\\/');
          $dirs[$key] = $dir . DIRECTORY_SEPARATOR . $dirPath;
        }
      }
      $file = basename($file);
      self::loadFile($file, $dirs, true);
    } else {
      self::_securityCheck($file);
      include_once 'external/' . $file;
    }
    
    if (! class_exists($class, false) && ! interface_exists($class, false)) {
      require_once 'external/Zend/Exception.php';
      throw new Zend_Exception("File \"$file\" does not exist or class \"$class\" was not found in the file");
    }
  }

  /**
   * Loads a PHP file.  This is a wrapper for PHP's include() function.
   *
   * $filename must be the complete filename, including any
   * extension such as ".php".  Note that a security check is performed that
   * does not permit extended characters in the filename.  This method is
   * intended for loading Zend Framework files.
   *
   * If $dirs is a string or an array, it will search the directories
   * in the order supplied, and attempt to load the first matching file.
   *
   * If the file was not found in the $dirs, or if no $dirs were specified,
   * it will attempt to load it from PHP's include_path.
   *
   * If $once is TRUE, it will use include_once() instead of include().
   *
   * @param  string        $filename
   * @param  string|array  $dirs - OPTIONAL either a path or array of paths
   *                       to search.
   * @param  boolean       $once
   * @return boolean
   * @throws Zend_Exception
   */
  public static function loadFile($filename, $dirs = null, $once = false) {
    self::_securityCheck($filename);
    
    /**
     * Search in provided directories, as well as include_path
     */
    $incPath = false;
    if (! empty($dirs) && (is_array($dirs) || is_string($dirs))) {
      if (is_array($dirs)) {
        $dirs = implode(PATH_SEPARATOR, $dirs);
      }
      $incPath = get_include_path();
      set_include_path($dirs . PATH_SEPARATOR . $incPath);
    }
    
    /**
     * Try finding for the plain filename in the include_path.
     */
    if ($once) {
      include_once $filename;
    } else {
      include $filename;
    }
    
    /**
     * If searching in directories, reset include_path
     */
    if ($incPath) {
      set_include_path($incPath);
    }
    
    return true;
  }

  /**
   * Returns TRUE if the $filename is readable, or FALSE otherwise.
   * This function uses the PHP include_path, where PHP's is_readable()
   * does not.
   *
   * @param string   $filename
   * @return boolean
   */
  public static function isReadable($filename) {
    if (! $fh = @fopen($filename, 'r', true)) {
      return false;
    }
    
    return true;
  }

  /**
   * spl_autoload() suitable implementation for supporting class autoloading.
   *
   * Attach to spl_autoload() using the following:
   * <code>
   * spl_autoload_register(array('Zend_Loader', 'autoload'));
   * </code>
   *
   * @param string $class
   * @return string|false Class name on success; false on failure
   */
  public static function autoload($class) {
    try {
      self::loadClass($class);
      return $class;
    } catch (Exception $e) {
      return false;
    }
  }

  /**
   * Register {@link autoload()} with spl_autoload()
   *
   * @param string $class (optional)
   * @param boolean $enabled (optional)
   * @return void
   * @throws Zend_Exception if spl_autoload() is not found
   * or if the specified class does not have an autoload() method.
   */
  public static function registerAutoload($class = 'Zend_Loader', $enabled = true) {
    if (! function_exists('spl_autoload_register')) {
      require_once 'external/Zend/Exception.php';
      throw new Zend_Exception('spl_autoload does not exist in this PHP installation');
    }
    
    self::loadClass($class);
    $methods = get_class_methods($class);
    if (! in_array('autoload', (array)$methods)) {
      require_once 'external/Zend/Exception.php';
      throw new Zend_Exception("The class \"$class\" does not have an autoload() method");
    }
    
    if ($enabled === true) {
      spl_autoload_register(array($class, 'autoload'));
    } else {
      spl_autoload_unregister(array($class, 'autoload'));
    }
  }

  /**
   * Ensure that filename does not contain exploits
   *
   * @param  string $filename
   * @return void
   * @throws Zend_Exception
   */
  protected static function _securityCheck($filename) {
    /**
     * Security check
     */
    if (preg_match('/[^a-z0-9\\/\\\\_.-]/i', $filename)) {
      require_once 'external/Zend/Exception.php';
      throw new Zend_Exception('Security check: Illegal character in filename');
    }
  }

  /**
   * Attempt to include() the file.
   *
   * include() is not prefixed with the @ operator because if
   * the file is loaded and contains a parse error, execution
   * will halt silently and this is difficult to debug.
   *
   * Always set display_errors = Off on production servers!
   *
   * @param  string  $filespec
   * @param  boolean $once
   * @return boolean
   * @deprecated Since 1.5.0; use loadFile() instead
   */
  protected static function _includeFile($filespec, $once = false) {
    if ($once) {
      return include_once $filespec;
    } else {
      return include $filespec;
    }
  }
}