Drizzled Public API Documentation

get_system_var.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/function/func.h>
00023 #include <drizzled/lex_string.h>
00024 
00025 namespace drizzled
00026 {
00027 
00028 class sys_var;
00029 
00030 Item *get_system_var(Session *session, sql_var_t var_type, LEX_STRING name,
00031                      LEX_STRING component);
00032 
00033 /* A system variable */
00034 
00035 class Item_func_get_system_var :public Item_func
00036 {
00037   sys_var *var;
00038   sql_var_t var_type;
00039   LEX_STRING component;
00040 
00041 public:
00042   Item_func_get_system_var(sys_var *var_arg, sql_var_t var_type_arg,
00043                            LEX_STRING *component_arg, const char *name_arg,
00044                            size_t name_len_arg);
00045   bool fix_fields(Session *session, Item **ref);
00046   /*
00047     Stubs for pure virtual methods. Should never be called: this
00048     item is always substituted with a constant in fix_fields().
00049   */
00050   double val_real()         { assert(0); return 0.0; }
00051   int64_t val_int()        { assert(0); return 0; }
00052   String* val_str(String*)  { assert(0); return 0; }
00053   void fix_length_and_dec() { assert(0); }
00054   /* TODO: fix to support views */
00055   const char *func_name() const { return "get_system_var"; }
00056 };
00057 
00058 
00059 } /* namespace drizzled */
00060