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/* Copyright (C) 2003 MySQL AB
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; either version 2 of the License, or
(at your option) any later version.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#ifndef ODBC_COMMON_ResultArea_hpp
#define ODBC_COMMON_ResultArea_hpp
#include <common/common.hpp>
#include <codegen/Code_base.hpp>
class SqlRow;
/**
* @class ResultArea
* @brief Execution result
*
* ResultArea contains general results from executing SQL
* statements. Data rows from queries are fetched via derived
* class ResultSet.
*/
class ResultArea {
public:
ResultArea();
virtual ~ResultArea();
/**
* Get number of rows:
*
* - for queries: number of rows fetched so far
* - for DML statements: number of rows affected
* - for DDL and other statements: 0
*/
CountType getCount() const;
protected:
void setCount(CountType count);
void addCount(unsigned count = 1);
private:
CountType m_count;
};
inline
ResultArea::ResultArea() :
m_count(0)
{
}
inline CountType
ResultArea::getCount() const
{
return m_count;
}
inline void
ResultArea::setCount(CountType count)
{
m_count = count;
}
inline void
ResultArea::addCount(unsigned count)
{
m_count += count;
}
/**
* @class ResultSet
* @brief Data rows from queries
*
* ResultSet is an interface implemented by SQL queries and
* virtual queries (such as SQLTables). It has an associated
* data row accessor SqlRow.
*/
class ResultSet : public ResultArea {
public:
ResultSet(const SqlRow& dataRow);
virtual ~ResultSet();
enum State {
State_init = 1, // before first fetch
State_ok = 2, // last fetch succeeded
State_end = 3 // end of fetch or error
};
void initState();
State getState() const;
/**
* Get data accessor. Can be retrieved once and used after
* each successful ResultSet::fetch().
*/
const SqlRow& dataRow() const;
/**
* Try to fetch one more row from this result set.
* - returns true if a row was fetched
* - returns false on end of fetch
* - returns false on error and sets error status
* It is a fatal error to call fetch after end of fetch.
*/
bool fetch(Ctx& ctx, Exec_base::Ctl& ctl);
protected:
/**
* Implementation of ResultSet::fetch() must be provided by
* each concrete subclass.
*/
virtual bool fetchImpl(Ctx& ctx, Exec_base::Ctl& ctl) = 0;
const SqlRow& m_dataRow;
State m_state;
};
inline
ResultSet::ResultSet(const SqlRow& dataRow) :
m_dataRow(dataRow),
m_state(State_end) // explicit initState() is required
{
}
inline const SqlRow&
ResultSet::dataRow() const
{
return m_dataRow;
}
inline void
ResultSet::initState()
{
m_state = State_init;
setCount(0);
}
inline ResultSet::State
ResultSet::getState() const
{
return m_state;
}
inline bool
ResultSet::fetch(Ctx& ctx, Exec_base::Ctl& ctl)
{
if (! (m_state == State_init || m_state == State_ok)) {
// should not happen but return error instead of assert
ctx.pushStatus(Error::Gen, "invalid fetch state %d", (int)m_state);
m_state = State_end;
return false;
}
if (fetchImpl(ctx, ctl)) {
m_state = State_ok;
addCount();
return true;
}
m_state = State_end;
return false;
}
#endif
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