Determine whether the user has a given privilege.

Parameters

$string: The permission, such as "administer nodes", being checked for.

$account: (optional) The account to check, if not given use currently logged in user.

Return value

Boolean TRUE if the current user has the requested permission.

All permission checks in Drupal should go through this function. This way, we guarantee consistent behavior, and ensure that the superuser can perform all actions.

File

drupal-7.x/modules/user/user.module, line 795

Enables the user registration and login system.

Code

function user_access($string, $account = NULL) {
  global $user;

  if (!isset($account)) {
    $account = $user;
  }

  // User #1 has all privileges:
  if ($account->uid == 1) {
    return TRUE;
  }

  // To reduce the number of SQL queries, we cache the user's permissions
  // in a static variable.
  // Use the advanced drupal_static() pattern, since this is called very often.
  static $drupal_static_fast;
  if (!isset($drupal_static_fast)) {
    $drupal_static_fast['perm'] = &drupal_static(__FUNCTION__);
  }
  $perm = &$drupal_static_fast['perm'];
  if (!isset($perm[$account->uid])) {
    $role_permissions = user_role_permissions($account->roles);

    $perms = array();
    foreach ($role_permissions as $one_role) {
      $perms += $one_role;
    }
    $perm[$account->uid] = $perms;
  }

  return isset($perm[$account->uid][$string]);
}