Drizzled Public API Documentation

query_id.h
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