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firebird-mirror/src/jrd/recsrc/SkipRowsStream.cpp
2013-08-21 07:18:26 +00:00

144 lines
3.3 KiB
C++

/*
* The contents of this file are subject to the Initial
* Developer's Public License Version 1.0 (the "License");
* you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
* http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
*
* Software distributed under the License is distributed AS IS,
* WITHOUT WARRANTY OF ANY KIND, either express or implied.
* See the License for the specific language governing rights
* and limitations under the License.
*
* The Original Code was created by John Bellardo
* for the Firebird Open Source RDBMS project.
*
* Copyright (c) 2000 John Bellardo <bellardo@users.sourceforge.net>
* and all contributors signed below.
*
* All Rights Reserved.
* Contributor(s): ______________________________________.
*/
#include "firebird.h"
#include "../jrd/jrd.h"
#include "../jrd/req.h"
#include "../jrd/cmp_proto.h"
#include "../jrd/evl_proto.h"
#include "../jrd/mov_proto.h"
#include "RecordSource.h"
using namespace Firebird;
using namespace Jrd;
// -------------------------------
// Data access: skip N rows filter
// -------------------------------
SkipRowsStream::SkipRowsStream(CompilerScratch* csb, RecordSource* next, ValueExprNode* value)
: m_next(next), m_value(value)
{
fb_assert(m_next && m_value);
m_impure = CMP_impure(csb, sizeof(Impure));
}
void SkipRowsStream::open(thread_db* tdbb) const
{
jrd_req* const request = tdbb->getRequest();
Impure* const impure = request->getImpure<Impure>(m_impure);
impure->irsb_flags = irsb_open;
const dsc* desc = EVL_expr(tdbb, request, m_value);
const SINT64 value = (desc && !(request->req_flags & req_null)) ? MOV_get_int64(desc, 0) : 0;
if (value < 0)
{
status_exception::raise(Arg::Gds(isc_bad_skip_param));
}
impure->irsb_count = value + 1;
m_next->open(tdbb);
}
void SkipRowsStream::close(thread_db* tdbb) const
{
jrd_req* const request = tdbb->getRequest();
invalidateRecords(request);
Impure* const impure = request->getImpure<Impure>(m_impure);
if (impure->irsb_flags & irsb_open)
{
impure->irsb_flags &= ~irsb_open;
m_next->close(tdbb);
}
}
bool SkipRowsStream::getRecord(thread_db* tdbb) const
{
if (--tdbb->tdbb_quantum < 0)
JRD_reschedule(tdbb, 0, true);
jrd_req* const request = tdbb->getRequest();
Impure* const impure = request->getImpure<Impure>(m_impure);
if (!(impure->irsb_flags & irsb_open))
return false;
while (impure->irsb_count > 1)
{
impure->irsb_count--;
if (!m_next->getRecord(tdbb))
return false;
}
impure->irsb_count--;
return m_next->getRecord(tdbb);
}
bool SkipRowsStream::refetchRecord(thread_db* tdbb) const
{
return m_next->refetchRecord(tdbb);
}
bool SkipRowsStream::lockRecord(thread_db* tdbb) const
{
return m_next->lockRecord(tdbb);
}
void SkipRowsStream::print(thread_db* tdbb, string& plan, bool detailed, unsigned level) const
{
if (detailed)
plan += printIndent(++level) + "Skip N Records";
m_next->print(tdbb, plan, detailed, level);
}
void SkipRowsStream::markRecursive()
{
m_next->markRecursive();
}
void SkipRowsStream::findUsedStreams(StreamList& streams, bool expandAll) const
{
m_next->findUsedStreams(streams, expandAll);
}
void SkipRowsStream::invalidateRecords(jrd_req* request) const
{
m_next->invalidateRecords(request);
}
void SkipRowsStream::nullRecords(thread_db* tdbb) const
{
m_next->nullRecords(tdbb);
}