-STG_LOCKER lock(&mutex, __FILE__, __LINE__);
-list<USER_IMPL>::const_iterator iter;
+std::lock_guard<std::mutex> lock(m_mutex);
+const_user_iter u;
+if (FindByNameNonLock(login, &u))
+ return -1;
+*user = &(*u);
+return 0;
+}
+//-----------------------------------------------------------------------------
+bool UsersImpl::Exists(const std::string & login) const
+{
+std::lock_guard<std::mutex> lock(m_mutex);
+const std::map<std::string, user_iter>::const_iterator iter(loginIndex.find(login));
+return iter != loginIndex.end();
+}
+//-----------------------------------------------------------------------------
+bool UsersImpl::TariffInUse(const std::string & tariffName) const
+{
+std::lock_guard<std::mutex> lock(m_mutex);
+std::list<UserImpl>::const_iterator iter;