<?php
// $Id: core.php,v 1.204 2008/10/08 22:13:55 drewish Exp $

/**
 * @file
 * These are the file specific hooks that are invoked by the Drupal core.
 *
 * Thes hooks are called in all modules at once using module_invoke_all().
 */

/**
 * @addtogroup hooks
 * @{
 */

/**
 * Load additional information into a file object.
 *
 * file_load() calls this hook to allow modules to load additional information
 * into the $file.
 *
 * @param $file
 *   The file object being loaded.
 * @return
 *   None.
 * @see file_load()
 */
function hook_file_load(&$file) {
  // Add the upload specific data into the file object.
  $values = db_query('SELECT * FROM {upload} u WHERE u.fid = :fid', array(':fid' => $file->fid))->fetch(PDO::FETCH_ASSOC);
  foreach ((array)$values as $key => $value) {
    $file->{$key} = $value;
  }
}

/**
 * Respond to a file is being saved.
 *
 * @param $file
 *   The file object being saved.
 * @return
 *   None.
 * @see file_save()
 */
function hook_file_save(&$file) {

}

/**
 * Report problems with a file.
 *
 * @param $file
 *   The file object being validated.
 * @return
 *   An optional array of error messages. If no problems were detected return
 *   NULL.
 * @see file_save()
 */
function hook_file_validate($file) {

}

/**
 * Respond to a file being added.
 *
 * @param $file
 *   The file that has just been created.
 * @return
 *   None.
 * @see file_save()
 */
function hook_file_insert(&$file) {

}

/**
 * Respond to a file being updated.
 *
 * @param $file
 *   The file that has just been updated.
 * @return
 *   None.
 * @see file_save()
 */
function hook_file_update(&$file) {

}

/**
 * Respond to a file that has been copied.
 *
 * @param $file
 *   The newly copied file object.
 * @param $source
 *   The original file before the copy.
 * @return
 *   None.
 * @see file_copy()
 */
function hook_file_copy($file, $source) { {

}

/**
 * Respond to a file that has been moved.
 *
 * @param $file
 *   The updated file object after the move.
 * @param $source
 *   The original file object before the move.
 * @return
 *   None.
 * @see file_move()
 */
function hook_file_move($file, $source) {

}

/**
 * Report the number of times a file is referenced by a module.
 *
 * This hook is called to determine if a files is in use. Multiple modules may
 * be referencing the same file and to prevent one from deleting a file used by
 * another this hook is called.
 *
 * @param $file
 *   The file object being checked for references.
 * @return
 *   If the module uses this file return an array with the module name as the
 *   key and the value the number of times the file is used.
 * @see file_delete()
 * @see upload_file_references()
 */
function hook_file_references($file) {
  // If upload.module is still using a file, do not let other modules delete it.
  $count = db_query('SELECT COUNT(*) FROM {upload} WHERE fid = :fid', array(':fid' => $file->fid))->fetchField();
  if ($count) {
    // Return the name of the module and how many references it has to the file.
    return array('upload' => $count);
  }
}

/**
  * Respond to a file being deleted.
 *
 * @param $file
 *   The file that has just been deleted.
 * @return
 *   None.
 * @see file_delete()
 * @see upload_file_delete()
 */
function hook_file_delete($file) {
  // Delete all information associated with the file.
  db_delete('upload')->condition('fid', $file->fid)->execute();
}

/**
 * Respond to a file that's status has changed.
 *
 * @param $file
 *   The file being changed.
 * @return
 *   None.
 * @see hook_file_status()
 */
function hook_file_status($file) {
}

/**
 * Control access to private file downloads and specify HTTP headers.
 *
 * This hook allows modules enforce permisisons on file downloads when the
 * private file download method is selected. Modules can also provide headers
 * to specify information like the file's name or MIME type.
 *
 * @param $filepath
 *   String of the file's path.
 * @return
 *   If the user does not have permission to access the file, return -1. If the
 *   user has permission, return an array with the appropriate headers. If the
 *   file is not controlled by the current module, the return value should be
 *   NULL.
 * @see file_download()
 */
function hook_file_download($filepath) {
  // Check if the file is controlled by the current module.
  $filepath = file_create_path($filepath);
  $result = db_query("SELECT f.* FROM {files} f INNER JOIN {upload} u ON f.fid = u.fid WHERE filepath = '%s'", $filepath);
  if ($file = db_fetch_object($result)) {
    if (!user_access('view uploaded files')) {
      return -1;
    }
    return array(
      'Content-Type: ' . $file->filemime,
      'Content-Length: ' . $file->filesize,
    );
  }
}