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/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
*
* Copyright (C) 2008 Sun Microsystems, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#pragma once
namespace drizzled {
/*
Item_type_holder used to store type. name, length of Item for UNIONS &
derived tables.
Item_type_holder do not need cleanup() because its time of live limited by
single SP/PS execution.
*/
class Item_type_holder: public Item
{
protected:
TYPELIB *enum_set_typelib;
enum_field_types fld_type;
/**
Get full information from Item about enum/set fields to be able to create
them later.
@param item Item for information collection
*/
void get_full_info(Item *item);
/* It is used to count decimal precision in join_types */
int prev_decimal_int_part;
public:
Item_type_holder(Session *session, Item *item);
/**
Return expression type of Item_type_holder.
@return
Item_result (type of internal Drizzle expression result)
*/
Item_result result_type() const;
enum_field_types field_type() const { return fld_type; };
enum Type type() const { return TYPE_HOLDER; }
double val_real();
int64_t val_int();
type::Decimal *val_decimal(type::Decimal *val);
String *val_str(String* val);
/**
Find field type which can carry current Item_type_holder type and
type of given Item.
@param session thread handler
@param item given item to join its parameters with this item ones
@retval
true error - types are incompatible
@retval
false OK
*/
bool join_types(Session *session, Item *item);
/**
Make temporary table field according collected information about type
of UNION result.
@param table temporary table for which we create fields
@return
created field
*/
Field *make_field_by_type(Table *table);
/**
Calculate lenth for merging result for given Item type.
@param item Item for length detection
@return
length
*/
static uint32_t display_length(Item *item);
/**
Find real field type of item.
@return
type of field which should be created to store item value
*/
static enum_field_types get_real_type(Item *item);
};
} /* namespace drizzled */
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