<?php
// $Id$

/*
 * Base FileTransfer class.
 *
 * Classes extending this class perform file operations on directories not
 * writeable by the webserver. To achieve this, the class should connect back
 * to the server using some backend (for example FTP or SSH). To keep security,
 * the password should always be asked from the user and never stored. For
 * safety, all methods operate only inside a "jail", by default the Drupal root.
 */
abstract class FileTransfer {
  protected $username;
  protected $password;
  protected $hostname = 'localhost';
  protected $port;

  /**
   * The constructer for the UpdateConnection class. This method is also called
   * from the classes that extend this class and override this method.
   */
  function __construct($jail) {
    $this->jail = $jail;
  }

  abstract static function factory($jail, $settings);

  /**
   * Implementation of the magic __get() method. If the connection isn't set to
   * anything, this will call the connect() method and set it to and return the
   * result; afterwards, the connection will be returned directly without using
   * this method.
   */
  function __get($name) {
    if ($name == 'connection') {
      $this->connect();
      return $this->connection;
    }

    if ($name == 'chroot') {
      $this->setChroot();
      return $this->chroot;
    }
  }

  /**
   * Connect to the server.
   */
  abstract protected function connect();

  /**
   * Copies a directory.
   *
   * @param $source
   *   The source path.
   * @param $destination
   *   The destination path.
   */
  public final function copyDirectory($source, $destination) {
    $source = $this->sanitizePath($source);
    $destination = $this->fixRemotePath($destination);
    $this->checkPath($destination);
    $this->copyDirectoryJailed($source, $destination);
  }

  /**
   * @see http://php.net/chmod
   *
   * @param string $path
   * @param long $mode
   * @param bool $recursive
   */
  public final function chmod($path, $mode, $recursive = FALSE) {
    if (!in_array('FileTransferChmodInterface', class_implements(get_class($this)))) {
      throw new FileTransferException('Unable to change file permissions');
    }
    $path = $this->sanitizePath($path);
    $path = $this->fixRemotePath($path);
    $this->checkPath($path);
    $this->chmodJailed($path, $mode, $recursive);
  }
  
  /**
   * Creates a directory.
   *
   * @param $directory
   *   The directory to be created.
   */
  public final function createDirectory($directory) {
    $directory = $this->fixRemotePath($directory);
    $this->checkPath($directory);
    $this->createDirectoryJailed($directory);
  }

  /**
   * Removes a directory.
   *
   * @param $directory
   *   The directory to be removed.
   */
  public final function removeDirectory($directory) {
    $directory = $this->fixRemotePath($directory);
    $this->checkPath($directory);
    $this->removeDirectoryJailed($directory);
  }

  /**
   * Copies a file.
   *
   * @param $source
   *   The source file.
   * @param $destination
   *   The destination file.
   */
  public final function copyFile($source, $destination) {
    $source = $this->sanitizePath($source);
    $destination = $this->fixRemotePath($destination);
    $this->checkPath($destination);
    $this->copyFileJailed($source, $destination);
  }

  /**
   * Removes a file.
   *
   * @param $destination
   *   The destination file to be removed.
   */
  public final function removeFile($destination) {
    $destination = $this->fixRemotePath($destination);
    $this->checkPath($destination);
    $this->removeFileJailed($destination);
  }

  /**
   * Checks that the path is inside the jail and throws an exception if not.
   *
   * @param $path
   *   A path to check against the jail.
   */
  protected final function checkPath($path) {
    $full_jail = $this->chroot . $this->jail;
    $full_path = drupal_realpath(substr($this->chroot . $path, 0, strlen($full_jail)));
    $full_path = $this->fixRemotePath($full_path, FALSE);
    if ($full_jail !== $full_path) {
      throw new FileTransferException('@directory is outside of the @jail', NULL, array('@directory' => $path, '@jail' => $this->jail));
    }
  }

  /**
   * Returns a modified path suitable for passing to the server.
   * If a path is a windows path, makes it posix compliant by removing the drive letter.
   * If $this->chroot has a value, it is stripped from the path to allow for
   * chroot'd filetransfer systems.
   *
   * @param $path
   * @param $strip_chroot
   *
   * @return string;
   */
  protected final function fixRemotePath($path, $strip_chroot = TRUE) {
    $path = $this->sanitizePath($path);
    $path = preg_replace('|^([a-z]{1}):|i', '', $path); // Strip out windows driveletter if its there.
    if ($strip_chroot) {
      if ($this->chroot && strpos($path, $this->chroot) === 0) {
        $path = ($path == $this->chroot) ? '' : substr($path, strlen($this->chroot));
      }
    }
    return $path;
  }

  /**
  * Changes backslahes to slashes, also removes a trailing slash.
  *
  * @param string $path
  * @return string;
  */
  function sanitizePath($path) {
    $path = str_replace('\\', '/', $path); // Windows path sanitiation.
    if (substr($path, -1) == '/') {
      $path = substr($path, 0, -1);
    }
    return $path;
  }

  /**
   * Copies a directory.
   *
   * We need a separate method to make the $destination is in the jail.
   *
   * @param $source
   *   The source path.
   * @param $destination
   *   The destination path.
   */
  protected function copyDirectoryJailed($source, $destination) {
    if ($this->isDirectory($destination)) {
      $destination = $destination . '/' . basename($source);
    }
    $this->createDirectory($destination);
    foreach (new RecursiveIteratorIterator(new RecursiveDirectoryIterator($source), RecursiveIteratorIterator::SELF_FIRST) as $filename => $file) {
      $relative_path = substr($filename, strlen($source));
      if ($file->isDir()) {
        $this->createDirectory($destination . $relative_path);
      }
      else {
        $this->copyFile($file->getPathName(), $destination . $relative_path);
      }
    }
  }

  /**
   * Creates a directory.
   *
   * @param $directory
   *   The directory to be created.
   */
  abstract protected function createDirectoryJailed($directory);

  /**
   * Removes a directory.
   *
   * @param $directory
   *   The directory to be removed.
   */
  abstract protected function removeDirectoryJailed($directory);

  /**
   * Copies a file.
   *
   * @param $source
   *   The source file.
   * @param $destination
   *   The destination file.
   */
  abstract protected function copyFileJailed($source, $destination);

  /**
   * Removes a file.
   *
   * @param $destination
   *   The destination file to be removed.
   */
  abstract protected function removeFileJailed($destination);

  /**
   * Checks if a particular path is a directory
   *
   * @param $path
   *   The path to check
   *
   * @return boolean
   */
  abstract public function isDirectory($path);

  /**
   * Checks if a particular path is a file (not a directory).
   *
   * @param $path
   *   The path to check
   *
   * @return boolean
   */
  abstract public function isFile($path);

  /**
   * Return the chroot property for this connection.
   *
   * It does this by moving up the tree until it finds itself. If successful,
   * it will return the chroot, otherwise FALSE.
   *
   * @return
   *   The chroot path for this connection or FALSE.
   */
  function findChroot() {
    // If the file exists as is, there is no chroot.
    $path = __FILE__;
    $path = $this->fixRemotePath($path, FALSE);
    if ($this->isFile($path)) {
      return FALSE;
    }

    $path = dirname(__FILE__);
    $path = $this->fixRemotePath($path, FALSE);
    $parts = explode('/', $path);
    $chroot = '';
    while (count($parts)) {
      $check = implode($parts, '/');
      if ($this->isFile($check . '/' . basename(__FILE__))) {
        // Remove the trailing slash.
        return substr($chroot,0,-1);
      }
      $chroot .= array_shift($parts) . '/';
    }
    return FALSE;
  }

  /**
   * Sets the chroot and changes the jail to match the correct path scheme
   *
   */
  function setChroot() {
    $this->chroot = $this->findChroot();
    $this->jail = $this->fixRemotePath($this->jail);
  }
}

/**
 * FileTransferException class.
 */
class FileTransferException extends Exception {
  public $arguments;

  function __construct($message, $code = 0, $arguments = array()) {
    parent::__construct($message, $code);
    $this->arguments = $arguments;
  }
}


/**
 * A FileTransfer Class implementing this interface can be used to chmod files.
 */
interface FileTransferChmodInterface {

  /**
   * Changes the permissions of the file / directory specified in $path
   *
   * @param string $path
   *   Path to change permissions of.
   * @param long $mode
   *   @see http://php.net/chmod
   * @param boolean $recursive
   *   Pass TRUE to recursively chmod the entire directory specified in $path.
   */
  function chmodJailed($path, $mode, $recursive);
}