00001 /* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*- 00002 * vim:expandtab:shiftwidth=2:tabstop=2:smarttab: 00003 * 00004 * Copyright (C) 2008 Sun Microsystems, Inc. 00005 * 00006 * This program is free software; you can redistribute it and/or modify 00007 * it under the terms of the GNU General Public License as published by 00008 * the Free Software Foundation; version 2 of the License. 00009 * 00010 * This program is distributed in the hope that it will be useful, 00011 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00013 * GNU General Public License for more details. 00014 * 00015 * You should have received a copy of the GNU General Public License 00016 * along with this program; if not, write to the Free Software 00017 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 00018 */ 00019 00020 #pragma once 00021 00022 #include <drizzled/atomics.h> 00023 00024 namespace drizzled 00025 { 00026 00027 typedef uint64_t query_id_t; 00028 00029 class Query_id 00030 { 00031 public: 00032 static Query_id& get_query_id() { 00033 static Query_id the_id; 00034 return the_id; 00035 } 00036 ~Query_id(); 00037 00038 /* return current query_id value */ 00039 query_id_t value() const; 00040 00041 /* increment query_id and return it. */ 00042 query_id_t next(); 00043 00044 private: 00045 atomic<uint64_t> the_query_id; 00046 00047 Query_id(); 00048 Query_id(Query_id const&); 00049 Query_id& operator=(Query_id const&); 00050 }; 00051 00052 } /* namespace drizzled */ 00053