<?php

/**

 * @file

 * Hooks for file module.

 */

/**

 * Control download access to files.

 *

 * The hook is typically implemented to limit access based on the entity the

 * file is referenced, e.g., only users with access to a node should be allowed

 * to download files attached to that node.

 *

 * @param array $file_item

 *   The array of information about the file to check access for.

 * @param $entity_type

 *   The type of $entity; for example, 'node' or 'user'.

 * @param $entity

 *   The $entity to which $file is referenced.

 *

 * @return

 *   TRUE is access should be allowed by this entity or FALSE if denied. Note

 *   that denial may be overridden by another entity controller, making this

 *   grant permissive rather than restrictive.

 *

 * @see hook_field_access().

 */

function hook_file_download_access($file_item, $entity_type, $entity) {

  if ($entity_type == 'node') {

    return node_access('view', $entity);

  }

}

/**

 * Alter the access rules applied to a file download.

 *

 * Entities that implement file management set the access rules for their

 * individual files. Module may use this hook to create custom access rules

 * for file downloads.

 *

 * @see hook_file_download_access().

 *

 * @param $grants

 *   An array of grants gathered by hook_file_download_access(). The array is

 *   keyed by the module that defines the entity type's access control; the

 *   values are Boolean grant responses for each module.

 * @param array $file_item

 *   The array of information about the file to alter access for.

 * @param $entity_type

 *   The type of $entity; for example, 'node' or 'user'.

 * @param $entity

 *   The $entity to which $file is referenced.

 */

function hook_file_download_access_alter(&$grants, $file_item, $entity_type, $entity) {

  // For our example module, we always enforce the rules set by node module.

  if (isset($grants['node'])) {

    $grants = array('node' => $grants['node']);

  }

}