greenplumn CParseHandlerLogicalLimit 源码

greenplumn CParseHandlerLogicalLimit 代码

文件路径：/src/backend/gporca/libnaucrates/src/parser/CParseHandlerLogicalLimit.cpp

//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2011 EMC Corp.
//
//	@filename:
//		CParseHandlerLogicalLimit.cpp
//
//	@doc:
//		Implementation of the SAX parse handler class for parsing logical
//		limit operators.
//---------------------------------------------------------------------------

#include "naucrates/dxl/parser/CParseHandlerLogicalLimit.h"

#include "naucrates/dxl/operators/CDXLLogicalLimit.h"
#include "naucrates/dxl/operators/CDXLOperatorFactory.h"
#include "naucrates/dxl/parser/CParseHandlerFactory.h"
#include "naucrates/dxl/parser/CParseHandlerScalarOp.h"
#include "naucrates/dxl/parser/CParseHandlerSortColList.h"

using namespace gpdxl;


XERCES_CPP_NAMESPACE_USE

//---------------------------------------------------------------------------
//	@function:
//		CParseHandlerLogicalLimit::CParseHandlerLogicalLimit
//
//	@doc:
//		Constructor
//
//---------------------------------------------------------------------------
CParseHandlerLogicalLimit::CParseHandlerLogicalLimit(
	CMemoryPool *mp, CParseHandlerManager *parse_handler_mgr,
	CParseHandlerBase *parse_handler_root)
	: CParseHandlerLogicalOp(mp, parse_handler_mgr, parse_handler_root)
{
}

//---------------------------------------------------------------------------
//	@function:
//		CParseHandlerLogicalLimit::StartElement
//
//	@doc:
//		Invoked by Xerces to process an opening tag
//
//---------------------------------------------------------------------------
void
CParseHandlerLogicalLimit::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(EdxltokenLogicalLimit),
								 element_local_name))
	{
		const XMLCh *non_removable_limit_str =
			attrs.getValue(CDXLTokens::XmlstrToken(EdxltokenTopLimitUnderDML));
		BOOL keep_limit = false;
		if (non_removable_limit_str)
		{
			keep_limit = CDXLOperatorFactory::ConvertAttrValueToBool(
				m_parse_handler_mgr->GetDXLMemoryManager(),
				non_removable_limit_str, EdxltokenTopLimitUnderDML,
				EdxltokenLogicalLimit);
		}

		m_dxl_node = GPOS_NEW(m_mp)
			CDXLNode(m_mp, GPOS_NEW(m_mp) CDXLLogicalLimit(m_mp, keep_limit));

		// create child node parsers

		// parse handler for logical operator
		CParseHandlerBase *child_parse_handler =
			CParseHandlerFactory::GetParseHandler(
				m_mp, CDXLTokens::XmlstrToken(EdxltokenLogical),
				m_parse_handler_mgr, this);
		m_parse_handler_mgr->ActivateParseHandler(child_parse_handler);

		CParseHandlerBase *offset_parse_handler =
			CParseHandlerFactory::GetParseHandler(
				m_mp, CDXLTokens::XmlstrToken(EdxltokenScalarLimitOffset),
				m_parse_handler_mgr, this);
		m_parse_handler_mgr->ActivateParseHandler(offset_parse_handler);

		CParseHandlerBase *count_parse_handler =
			CParseHandlerFactory::GetParseHandler(
				m_mp, CDXLTokens::XmlstrToken(EdxltokenScalarLimitCount),
				m_parse_handler_mgr, this);
		m_parse_handler_mgr->ActivateParseHandler(count_parse_handler);

		// parse handler for the sorting column list
		CParseHandlerBase *sort_col_list_parse_handler =
			CParseHandlerFactory::GetParseHandler(
				m_mp, CDXLTokens::XmlstrToken(EdxltokenScalarSortColList),
				m_parse_handler_mgr, this);
		m_parse_handler_mgr->ActivateParseHandler(sort_col_list_parse_handler);

		// store child parse handler in array
		this->Append(sort_col_list_parse_handler);
		this->Append(count_parse_handler);
		this->Append(offset_parse_handler);
		this->Append(child_parse_handler);
	}
	else
	{
		CWStringDynamic *str = CDXLUtils::CreateDynamicStringFromXMLChArray(
			m_parse_handler_mgr->GetDXLMemoryManager(), element_local_name);
		GPOS_RAISE(gpdxl::ExmaDXL, gpdxl::ExmiDXLUnexpectedTag,
				   str->GetBuffer());
	}
}

//---------------------------------------------------------------------------
//	@function:
//		CParseHandlerLogicalLimit::EndElement
//
//	@doc:
//		Invoked by Xerces to process a closing tag
//
//---------------------------------------------------------------------------
void
CParseHandlerLogicalLimit::EndElement(const XMLCh *const,  // element_uri,
									  const XMLCh *const element_local_name,
									  const XMLCh *const  // element_qname
)
{
	if (0 !=
		XMLString::compareString(CDXLTokens::XmlstrToken(EdxltokenLogicalLimit),
								 element_local_name))
	{
		CWStringDynamic *str = CDXLUtils::CreateDynamicStringFromXMLChArray(
			m_parse_handler_mgr->GetDXLMemoryManager(), element_local_name);
		GPOS_RAISE(gpdxl::ExmaDXL, gpdxl::ExmiDXLUnexpectedTag,
				   str->GetBuffer());
	}

	GPOS_ASSERT(nullptr != m_dxl_node);
	GPOS_ASSERT(4 == this->Length());

	CParseHandlerSortColList *sort_col_list_parse_handler =
		dynamic_cast<CParseHandlerSortColList *>((*this)[0]);
	CParseHandlerScalarOp *count_parse_handler =
		dynamic_cast<CParseHandlerScalarOp *>((*this)[1]);
	CParseHandlerScalarOp *offset_parse_handler =
		dynamic_cast<CParseHandlerScalarOp *>((*this)[2]);
	CParseHandlerLogicalOp *child_parse_handler =
		dynamic_cast<CParseHandlerLogicalOp *>((*this)[3]);

	GPOS_ASSERT(nullptr != child_parse_handler->CreateDXLNode());

	AddChildFromParseHandler(sort_col_list_parse_handler);
	AddChildFromParseHandler(count_parse_handler);
	AddChildFromParseHandler(offset_parse_handler);
	AddChildFromParseHandler(child_parse_handler);

#ifdef GPOS_DEBUG
	m_dxl_node->GetOperator()->AssertValid(m_dxl_node,
										   false /* validate_children */);
#endif	// GPOS_DEBUG

	// deactivate handler
	m_parse_handler_mgr->DeactivateHandler();
}
// EOF

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