greenplumn CParseHandlerScalarLimitCount 代码
文件路径：/src/backend/gporca/libnaucrates/src/parser/CParseHandlerScalarLimitCount.cpp
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2011 Greenplum, Inc.
/
/ @filename:
/ CParseHandlerScalarLimitCount.cpp
/
/ @doc:
/ Implementation of the SAX parse handler class for parsing LimitCount
/
/---------------------------------------------------------------------------
#include "naucrates/dxl/parser/CParseHandlerScalarLimitCount.h"
#include "naucrates/dxl/operators/CDXLOperatorFactory.h"
#include "naucrates/dxl/operators/CDXLScalarLimitCount.h"
#include "naucrates/dxl/parser/CParseHandlerFactory.h"
#include "naucrates/dxl/parser/CParseHandlerScalarOp.h"
using namespace gpdxl;
XERCES_CPP_NAMESPACE_USE
/---------------------------------------------------------------------------
/ @function:
/ CParseHandlerScalarLimitCount::CParseHandlerScalarLimitCount
/
/ @doc:
/ Constructor
/
/---------------------------------------------------------------------------
CParseHandlerScalarLimitCount::CParseHandlerScalarLimitCount(
CMemoryPool *mp, CParseHandlerManager *parse_handler_mgr,
CParseHandlerBase *parse_handler_root)
: CParseHandlerScalarOp(mp, parse_handler_mgr, parse_handler_root)
{
}
/---------------------------------------------------------------------------
/ @function:
/ CParseHandlerScalarLimitCount::StartElement
/
/ @doc:
/ Invoked by Xerces to process an opening tag
/
/---------------------------------------------------------------------------
void
CParseHandlerScalarLimitCount::StartElement(
const XMLCh *const element_uri, const XMLCh *const element_local_name,
const XMLCh *const element_qname, const Attributes &attrs)
{
if (0 == XMLString::compareString(
CDXLTokens::XmlstrToken(EdxltokenScalarLimitCount),
element_local_name))
{
/ parse and create scalar limit count
CDXLScalarLimitCount *dxl_op =
(CDXLScalarLimitCount *) CDXLOperatorFactory::MakeDXLLimitCount(
m_parse_handler_mgr->GetDXLMemoryManager(), attrs);
m_dxl_node = GPOS_NEW(m_mp) CDXLNode(m_mp, dxl_op);
}
else
{
/ we must have seen a LIMITCOUNT already and initialized its corresponding node
if (nullptr == m_dxl_node)
{
CWStringDynamic *str = CDXLUtils::CreateDynamicStringFromXMLChArray(
m_parse_handler_mgr->GetDXLMemoryManager(), element_local_name);
GPOS_RAISE(gpdxl::ExmaDXL, gpdxl::ExmiDXLUnexpectedTag,
str->GetBuffer());
}
/ install a scalar element parser for parsing the limit count element
CParseHandlerBase *child_parse_handler =
CParseHandlerFactory::GetParseHandler(
m_mp, CDXLTokens::XmlstrToken(EdxltokenScalar),
m_parse_handler_mgr, this);
m_parse_handler_mgr->ActivateParseHandler(child_parse_handler);
/ store parse handler
this->Append(child_parse_handler);
child_parse_handler->startElement(element_uri, element_local_name,
element_qname, attrs);
}
}
/---------------------------------------------------------------------------
/ @function:
/ CParseHandlerScalarLimitCount::EndElement
/
/ @doc:
/ Processes a Xerces end element event
/
/---------------------------------------------------------------------------
void
CParseHandlerScalarLimitCount::EndElement(const XMLCh *const, / element_uri,
const XMLCh *const element_local_name,
const XMLCh *const / element_qname
)
{
if (0 != XMLString::compareString(
CDXLTokens::XmlstrToken(EdxltokenScalarLimitCount),
element_local_name))
{
CWStringDynamic *str = CDXLUtils::CreateDynamicStringFromXMLChArray(
m_parse_handler_mgr->GetDXLMemoryManager(), element_local_name);
GPOS_RAISE(gpdxl::ExmaDXL, gpdxl::ExmiDXLUnexpectedTag,
str->GetBuffer());
}
const ULONG size = this->Length();
if (0 < size)
{
GPOS_ASSERT(1 == size);
/ limit count node was not empty
CParseHandlerScalarOp *child_parse_handler =
dynamic_cast<CParseHandlerScalarOp *>((*this)[0]);
AddChildFromParseHandler(child_parse_handler);
}
/ deactivate handler
m_parse_handler_mgr->DeactivateHandler();
}
/ EOF
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