og_subgroups.module

<?php
/**
 * @file
 * Enable defining hierarchy of groups for organic groups.
 */


/**
 * Check if a user has access permmission (given) in one of the encestors groups
 * and retuen the tree structure of the group hierarchy.
 *
 * @param $entity_groups
 *    Array of group id to check and start moving up in the hierarchy.
 *
 * @param $account
 *    Optional; The account to check
 * @param $string_perm
 *    Optional; The permission string, if empty return the full tree stucture in
 *    $structure, otherwise stops when the permission is grant.
 * @param $structure
 * 		Optional; This is the array that you should send by ref to get back the 
 * 		all the tree structure of the given groups.
 *    Array contain 2 keys ['gid'] - group id, and ['level'] the depth of the 
 *    parent.
 * @param $level
 * 		Optional; Level of tree to start counting from, nomaly no need to change 
 * 		this. Deafult 0 beeing the entity given.
 * 
 *	@return
 *		TRUE if user has access grant with the given perm to one of the enstertors 
 *		groups.
 */
function og_subgroups_get_reverse_hierarchy_tree_perm($entity_groups, $string = '', $account = NULL, &$structure = array(), $level = 0) {
  // Check if user has the permission in a parent group.
  foreach($entity_groups as $gid) {
    // Save the hierarchy structure.
    $structure[$gid] = array();
    $structure[$gid]['gid'] = $gid;
    $structure[$gid]['level'] = $level;
    if ($string) {
      if (og_user_access($gid, $string, $account, TRUE)) {
        return TRUE;
      }
    }
  }
  // Get all groups that are content of user_groups (as an array of group ids).
  $groups = og_load_multiple($entity_groups);
  $parent_groups = array();
  foreach ($groups as $group) {
    // Load the entity associated with the group.
    $entity = og_load_entity_from_group($group->gid);
    // Get all groups that are associated with passed group.
    $parent_groups += og_get_entity_groups($group->entity_type, $entity);
  }
  if ($parent_groups) {
    // Recurssion call of the function.
    return  og_subgroups_get_reverse_hierarchy_tree_perm($parent_groups, $string, $account, $structure, ++$level);
  }
  else {
    // Reached a dead end, return false.
    return FALSE;
  }
}

/**
 * Implements hook_og_user_access_alter()
 */
function og_subgroups_og_user_access_alter(&$perm, $context) {
  // Update the permission for a user that tries to access a sub group.
  // This gives to any users his og group permission to all his subgroups,
  //  without the -need for him to be a member in the groups.
  $perm[$context['string']] = og_subgroups_get_reverse_hierarchy_tree_perm(array($context['group']->gid),  $context['string'], $context['account']);
}


/**
 * Implements hook_node_access_records_alter().
 * 
 * This alter is fired on node save, we want to add view permission to a user's
 * subgroups (private groups), to do so we add the parent groups id to all 
 * groups.
 */
function og_subgroups_node_access_records_alter(&$grants, $node) {
  // Relevant only for private groups.
  if (module_exists('og_access')) {
    // The group IDs, that in case access is granted, will be recorded.
    $gids = array();
    $private = FALSE;
    $groups = array();
    // Dealing with a node group that is private.
    if (!empty($node->{OG_ACCESS_FIELD}[LANGUAGE_NONE][0]['value'])) {
      $group = og_get_group('node', $node->nid);
      if ($group) {
        $groups[] = $group->gid;
        $private = TRUE;
      }
    }
    // Dealing with a group content.
    elseif (isset($node->{OG_CONTENT_ACCESS_FIELD}[LANGUAGE_NONE][0]['value'])) {
      // If no groups with og realm are defined, this means it's a public group
      //  then do nothing, otherwise treat as a private group.
      if (($node->{OG_CONTENT_ACCESS_FIELD}[LANGUAGE_NONE][0]['value'] == OG_CONTENT_ACCESS_PRIVATE) ||
      ($node->{OG_CONTENT_ACCESS_FIELD}[LANGUAGE_NONE][0]['value'] == OG_CONTENT_ACCESS_DEFAULT && og_subgroups_grants_has_og_realm($grants))) {
        $groups = og_get_entity_groups('node', $node);
        $private = TRUE;
      }
    }
    // If group is private, then grant permissions for parent groups.
    if ($private) {
      og_subgroups_get_reverse_hierarchy_tree_perm($groups,'', NULL, $gids);
      // Check existing grant and remove from gids[], to avoid duplication.
      foreach ($grants as $granted) {
        if (isset($gids[$granted['gid']])) {
          unset($gids[$granted['gid']]);
        }
      }
      // Build the new access Grant array.
      foreach ($gids as $gid) {
        $grants[] = array (
        'realm' => OG_ACCESS_AUTHENTICATED_REALM,
        'gid' => $gid['gid'],
        'grant_view' => 1,
        'grant_update' => 0,
        'grant_delete' => 0,
        'priority' => 0,
        );
      }
    }
  }
}
/*
 * @return TRUE if $grants contain an OG realm
 */
function og_subgroups_grants_has_og_realm($grants) {
  foreach ($grants as $granted) {
    if ($granted['realm'] == OG_ACCESS_AUTHENTICATED_REALM) {
      return TRUE;
    }
  }
  return FALSE;
}