greenplumn CParseHandlerScalarNullTest 源码

greenplumn CParseHandlerScalarNullTest 代码

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

//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2011 Greenplum, Inc.
//
//	@filename:
//		CParseHandlerScalarNullTest.cpp
//
//	@doc:
//
//		Implementation of the SAX parse handler class for parsing scalar NullTest.
//---------------------------------------------------------------------------

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

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


using namespace gpdxl;


XERCES_CPP_NAMESPACE_USE

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


//---------------------------------------------------------------------------
//	@function:
//		CParseHandlerScalarNullTest::StartElement
//
//	@doc:
//		Processes a Xerces start element event
//
//---------------------------------------------------------------------------
void
CParseHandlerScalarNullTest::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(EdxltokenScalarIsNull),
				  element_local_name)) ||
		(0 == XMLString::compareString(
				  CDXLTokens::XmlstrToken(EdxltokenScalarIsNotNull),
				  element_local_name)))
	{
		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());
		}

		BOOL is_null = true;

		if (0 == XMLString::compareString(
					 CDXLTokens::XmlstrToken(EdxltokenScalarIsNotNull),
					 element_local_name))
		{
			is_null = false;
		}

		// parse and create scalar NullTest
		CDXLScalarNullTest *dxl_op =
			(CDXLScalarNullTest *) CDXLOperatorFactory::MakeDXLNullTest(
				m_parse_handler_mgr->GetDXLMemoryManager(), is_null);

		// construct node from the created child node
		m_dxl_node = GPOS_NEW(m_mp) CDXLNode(m_mp, dxl_op);

		// parse handler for child scalar node
		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);
	}
	else
	{
		CWStringDynamic *str = CDXLUtils::CreateDynamicStringFromXMLChArray(
			m_parse_handler_mgr->GetDXLMemoryManager(), element_local_name);
		GPOS_RAISE(gpdxl::ExmaDXL, gpdxl::ExmiDXLUnexpectedTag,
				   str->GetBuffer());
	}
}

//---------------------------------------------------------------------------
//	@function:
//		CParseHandlerScalarNullTest::EndElement
//
//	@doc:
//		Processes a Xerces end element event
//
//---------------------------------------------------------------------------
void
CParseHandlerScalarNullTest::EndElement(const XMLCh *const,	 // element_uri,
										const XMLCh *const element_local_name,
										const XMLCh *const	// element_qname
)
{
	if ((0 != XMLString::compareString(
				  CDXLTokens::XmlstrToken(EdxltokenScalarIsNull),
				  element_local_name)) &&
		(0 != XMLString::compareString(
				  CDXLTokens::XmlstrToken(EdxltokenScalarIsNotNull),
				  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(1 == this->Length());


	// add constructed child from child parse handler
	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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