<?php

/**

 * @file

 * Classes used for updating various files in the Drupal webroot. These

 * classes use a FileTransfer object to actually perform the operations.

 * Normally, the FileTransfer is provided when the site owner is redirected to

 * authorize.php as part of a multistep process.

 */

/**

 * Interface for a class which can update a Drupal project.

 *

 * An Updater currently serves the following purposes:

 *   - It can take a given directory, and determine if it can operate on it.

 *   - It can move the contents of that directory into the appropriate place

 *     on the system using FileTransfer classes.

 *   - It can return a list of "next steps" after an update or install.

 *   - In the future, it will most likely perform some of those steps as well.

 */

interface DrupalUpdaterInterface {

  /**

   * Checks if the project is installed.

   *

   * @return bool

   */

  public function isInstalled();

  /**

   * Returns the system name of the project.

   *

   * @param string $directory

   *  A directory containing a project.

   */

  public static function getProjectName($directory);

  /**

   * @return string

   *   An absolute path to the default install location.

   */

  public function getInstallDirectory();

  /**

   * Determine if the Updater can handle the project provided in $directory.

   *

   * @todo: Provide something more rational here, like a project spec file.

   *

   * @param string $directory

   *

   * @return bool

   *   TRUE if the project is installed, FALSE if not.

   */

  public static function canUpdateDirectory($directory);

  /**

   * Actions to run after an install has occurred.

   */

  public function postInstall();

  /**

   * Actions to run after an update has occurred.

   */

  public function postUpdate();

}

/**

 * Base class for Updaters used in Drupal.

 */

class Updater {

  /**

   * @var string $source Directory to install from.

   */

  public $source;

  public function __construct($source) {

    $this->source = $source;

    $this->name = self::getProjectName($source);

    $this->title = self::getProjectTitle($source);

  }

  /**

   * Return an Updater of the appropriate type depending on the source.

   *

   * If a directory is provided which contains a module, will return a

   * ModuleUpdater.

   *

   * @param string $source

   *   Directory of a Drupal project.

   *

   * @return Updater

   */

  public static function factory($source) {

    if (is_dir($source)) {

      $updater = self::getUpdaterFromDirectory($source);

    }

    else {

      throw new UpdaterException(t('Unable to determine the type of the source directory.'));

    }

    return new $updater($source);

  }

  /**

   * Determine which Updater class can operate on the given directory.

   *

   * @param string $directory

   *   Extracted Drupal project.

   *

   * @return string

   *   The class name which can work with this project type.

   */

  public static function getUpdaterFromDirectory($directory) {

    // Gets a list of possible implementing classes.

    $updaters = drupal_get_updaters();

    foreach ($updaters as $updater) {

      $class = $updater['class'];

      if (call_user_func(array($class, 'canUpdateDirectory'), $directory)) {

        return $class;

      }

    }

    throw new UpdaterException(t('Cannot determine the type of project.'));

  }

  /**

   * Figure out what the most important (or only) info file is in a directory.

   *

   * Since there is no enforcement of which info file is the project's "main"

   * info file, this will get one with the same name as the directory, or the

   * first one it finds.  Not ideal, but needs a larger solution.

   *

   * @param string $directory

   *   Directory to search in.

   *

   * @return string

   *   Path to the info file.

   */

  public static function findInfoFile($directory) {

    $info_files = file_scan_directory($directory, '/.*\.info$/');

    if (!$info_files) {

      return FALSE;

    }

    foreach ($info_files as $info_file) {

      if (drupal_substr($info_file->filename, 0, -5) == drupal_basename($directory)) {

        // Info file Has the same name as the directory, return it.

        return $info_file->uri;

      }

    }

    // Otherwise, return the first one.

    $info_file = array_shift($info_files);

    return $info_file->uri;

  }

  /**

   * Get the name of the project directory (basename).

   *

   * @todo: It would be nice, if projects contained an info file which could

   *        provide their canonical name.

   *

   * @param string $directory

   *

   * @return string

   *   The name of the project.

   */

  public static function getProjectName($directory) {

    return drupal_basename($directory);

  }

  /**

   * Return the project name from a Drupal info file.

   *

   * @param string $directory

   *   Directory to search for the info file.

   *

   * @return string

   *   The title of the project.

   */

  public static function getProjectTitle($directory) {

    $info_file = self::findInfoFile($directory);

    $info = drupal_parse_info_file($info_file);

    if (empty($info)) {

      throw new UpdaterException(t('Unable to parse info file: %info_file.', array('%info_file' => $info_file)));

    }

    if (empty($info['name'])) {

      throw new UpdaterException(t("The info file (%info_file) does not define a 'name' attribute.", array('%info_file' => $info_file)));

    }

    return $info['name'];

  }

  /**

   * Store the default parameters for the Updater.

   *

   * @param array $overrides

   *   An array of overrides for the default parameters.

   *

   * @return array

   *   An array of configuration parameters for an update or install operation.

   */

  protected function getInstallArgs($overrides = array()) {

    $args = array(

      'make_backup' => FALSE,

      'install_dir' => $this->getInstallDirectory(),

      'backup_dir'  => $this->getBackupDir(),

    );

    return array_merge($args, $overrides);

  }

  /**

   * Updates a Drupal project, returns a list of next actions.

   *

   * @param FileTransfer $filetransfer

   *   Object that is a child of FileTransfer. Used for moving files

   *   to the server.

   * @param array $overrides

   *   An array of settings to override defaults; see self::getInstallArgs().

   *

   * @return array

   *   An array of links which the user may need to complete the update

   */

  public function update(&$filetransfer, $overrides = array()) {

    try {

      // Establish arguments with possible overrides.

      $args = $this->getInstallArgs($overrides);

      // Take a Backup.

      if ($args['make_backup']) {

        $this->makeBackup($args['install_dir'], $args['backup_dir']);

      }

      if (!$this->name) {

        // This is bad, don't want to delete the install directory.

        throw new UpdaterException(t('Fatal error in update, cowardly refusing to wipe out the install directory.'));

      }

      // Make sure the installation parent directory exists and is writable.

      $this->prepareInstallDirectory($filetransfer, $args['install_dir']);

      // Note: If the project is installed in sites/all, it will not be

      // deleted. It will be installed in sites/default as that will override

      // the sites/all reference and not break other sites which are using it.

      if (is_dir($args['install_dir'] . '/' . $this->name)) {

        // Remove the existing installed file.

        $filetransfer->removeDirectory($args['install_dir'] . '/' . $this->name);

      }

      // Copy the directory in place.

      $filetransfer->copyDirectory($this->source, $args['install_dir']);

      // Make sure what we just installed is readable by the web server.

      $this->makeWorldReadable($filetransfer, $args['install_dir'] . '/' . $this->name);

      // Run the updates.

      // @TODO: decide if we want to implement this.

      $this->postUpdate();

      // For now, just return a list of links of things to do.

      return $this->postUpdateTasks();

    }

    catch (FileTransferException $e) {

      throw new UpdaterFileTransferException(t('File Transfer failed, reason: !reason', array('!reason' => strtr($e->getMessage(), $e->arguments))));

    }

  }

  /**

   * Installs a Drupal project, returns a list of next actions.

   *

   * @param FileTransfer $filetransfer

   *   Object that is a child of FileTransfer.

   * @param array $overrides

   *   An array of settings to override defaults; see self::getInstallArgs().

   *

   * @return array

   *   An array of links which the user may need to complete the install.

   */

  public function install(&$filetransfer, $overrides = array()) {

    try {

      // Establish arguments with possible overrides.

      $args = $this->getInstallArgs($overrides);

      // Make sure the installation parent directory exists and is writable.

      $this->prepareInstallDirectory($filetransfer, $args['install_dir']);

      // Copy the directory in place.

      $filetransfer->copyDirectory($this->source, $args['install_dir']);

      // Make sure what we just installed is readable by the web server.

      $this->makeWorldReadable($filetransfer, $args['install_dir'] . '/' . $this->name);

      // Potentially enable something?

      // @TODO: decide if we want to implement this.

      $this->postInstall();

      // For now, just return a list of links of things to do.

      return $this->postInstallTasks();

    }

    catch (FileTransferException $e) {

      throw new UpdaterFileTransferException(t('File Transfer failed, reason: !reason', array('!reason' => strtr($e->getMessage(), $e->arguments))));

    }

  }

  /**

   * Make sure the installation parent directory exists and is writable.

   *

   * @param FileTransfer $filetransfer

   *   Object which is a child of FileTransfer.

   * @param string $directory

   *   The installation directory to prepare.

   */

  public function prepareInstallDirectory(&$filetransfer, $directory) {

    // Make the parent dir writable if need be and create the dir.

    if (!is_dir($directory)) {

      $parent_dir = dirname($directory);

      if (!is_writable($parent_dir)) {

        @chmod($parent_dir, 0755);

        // It is expected that this will fail if the directory is owned by the

        // FTP user. If the FTP user == web server, it will succeed.

        try {

          $filetransfer->createDirectory($directory);

          $this->makeWorldReadable($filetransfer, $directory);

        }

        catch (FileTransferException $e) {

          // Probably still not writable. Try to chmod and do it again.

          // @todo: Make a new exception class so we can catch it differently.

          try {

            $old_perms = substr(sprintf('%o', fileperms($parent_dir)), -4);

            $filetransfer->chmod($parent_dir, 0755);

            $filetransfer->createDirectory($directory);

            $this->makeWorldReadable($filetransfer, $directory);

            // Put the permissions back.

            $filetransfer->chmod($parent_dir, intval($old_perms, 8));

          }

          catch (FileTransferException $e) {

            $message = t($e->getMessage(), $e->arguments);

            $throw_message = t('Unable to create %directory due to the following: %reason', array('%directory' => $directory, '%reason' => $message));

            throw new UpdaterException($throw_message);

          }

        }

        // Put the parent directory back.

        @chmod($parent_dir, 0555);

      }

    }

  }

  /**

   * Ensure that a given directory is world readable.

   *

   * @param FileTransfer $filetransfer

   *   Object which is a child of FileTransfer.

   * @param string $path

   *   The file path to make world readable.

   * @param bool $recursive

   *   If the chmod should be applied recursively.

   */

  public function makeWorldReadable(&$filetransfer, $path, $recursive = TRUE) {

    if (!is_executable($path)) {

      // Set it to read + execute.

      $new_perms = substr(sprintf('%o', fileperms($path)), -4, -1) . "5";

      $filetransfer->chmod($path, intval($new_perms, 8), $recursive);

    }

  }

  /**

   * Perform a backup.

   *

   * @todo Not implemented.

   */

  public function makeBackup(&$filetransfer, $from, $to) {

  }

  /**

   * Return the full path to a directory where backups should be written.

   */

  public function getBackupDir() {

    return file_stream_wrapper_get_instance_by_scheme('temporary')->getDirectoryPath();

  }

  /**

   * Perform actions after new code is updated.

   */

  public function postUpdate() {

  }

  /**

   * Perform actions after installation.

   */

  public function postInstall() {

  }

  /**

   * Return an array of links to pages that should be visited post operation.

   *

   * @return array

   *   Links which provide actions to take after the install is finished.

   */

  public function postInstallTasks() {

    return array();

  }

  /**

   * Return an array of links to pages that should be visited post operation.

   *

   * @return array

   *   Links which provide actions to take after the update is finished.

   */

  public function postUpdateTasks() {

    return array();

  }

}

/**

 * Exception class for the Updater class hierarchy.

 *

 * This is identical to the base Exception class, we just give it a more

 * specific name so that call sites that want to tell the difference can

 * specifically catch these exceptions and treat them differently.

 */

class UpdaterException extends Exception {

}

/**

 * Child class of UpdaterException that indicates a FileTransfer exception.

 *

 * We have to catch FileTransfer exceptions and wrap those in t(), since

 * FileTransfer is so low-level that it doesn't use any Drupal APIs and none

 * of the strings are translated.

 */

class UpdaterFileTransferException extends UpdaterException {

}