greenplumn CParseHandlerValuesScan 源码

  • 2022-08-18
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greenplumn CParseHandlerValuesScan 代码

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

//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2017 VMware, Inc. or its affiliates.
//
//	@filename:
//		CParseHandlerValuesScan.cpp
//
//	@doc:
//
//		Implementation of the SAX parse handler class for parsing value scan
//		operator
//---------------------------------------------------------------------------

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

#include "naucrates/dxl/CDXLUtils.h"
#include "naucrates/dxl/operators/CDXLOperatorFactory.h"
#include "naucrates/dxl/parser/CParseHandlerFactory.h"
#include "naucrates/dxl/parser/CParseHandlerPhysicalOp.h"
#include "naucrates/dxl/parser/CParseHandlerProjList.h"
#include "naucrates/dxl/parser/CParseHandlerProperties.h"
#include "naucrates/dxl/parser/CParseHandlerScalarValuesList.h"
#include "naucrates/dxl/parser/CParseHandlerUtils.h"

using namespace gpdxl;

XERCES_CPP_NAMESPACE_USE


//	ctor
CParseHandlerValuesScan::CParseHandlerValuesScan(
	CMemoryPool *mp, CParseHandlerManager *parse_handler_mgr,
	CParseHandlerBase *parse_handler_root)
	: CParseHandlerPhysicalOp(mp, parse_handler_mgr, parse_handler_root)
{
}


//	processes a Xerces start element event
void
CParseHandlerValuesScan::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(EdxltokenPhysicalValuesScan),
				 element_local_name))
	{
		m_dxl_op = GPOS_NEW(m_mp) CDXLPhysicalValuesScan(m_mp);

		// parse handler for the proj list
		CParseHandlerBase *proj_list_parse_handler =
			CParseHandlerFactory::GetParseHandler(
				m_mp, CDXLTokens::XmlstrToken(EdxltokenScalarProjList),
				m_parse_handler_mgr, this);
		m_parse_handler_mgr->ActivateParseHandler(proj_list_parse_handler);

		//parse handler for the properties of the operator
		CParseHandlerBase *prop_parse_handler =
			CParseHandlerFactory::GetParseHandler(
				m_mp, CDXLTokens::XmlstrToken(EdxltokenProperties),
				m_parse_handler_mgr, this);
		m_parse_handler_mgr->ActivateParseHandler(prop_parse_handler);

		// store parse handlers
		this->Append(prop_parse_handler);
		this->Append(proj_list_parse_handler);
	}
	else
	{
		// parse scalar child
		CParseHandlerBase *child_parse_handler =
			CParseHandlerFactory::GetParseHandler(
				m_mp, CDXLTokens::XmlstrToken(EdxltokenScalarValuesList),
				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);
	}
}

//	processes a Xerces end element event
void
CParseHandlerValuesScan::EndElement(const XMLCh *const,	 // element_uri,
									const XMLCh *const element_local_name,
									const XMLCh *const	// element_qname
)
{
	if (0 != XMLString::compareString(
				 CDXLTokens::XmlstrToken(EdxltokenPhysicalValuesScan),
				 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 arity = this->Length();
	GPOS_ASSERT(3 <= arity);

	m_dxl_node = GPOS_NEW(m_mp) CDXLNode(m_mp, m_dxl_op);

	// valuesscan has properties element as its first child
	CParseHandlerProperties *prop_parse_handler =
		dynamic_cast<CParseHandlerProperties *>((*this)[0]);

	// set statistics and physical properties
	CParseHandlerUtils::SetProperties(m_dxl_node, prop_parse_handler);

	// valuesscan has project list element as its second child
	CParseHandlerProjList *proj_list_parse_handler =
		dynamic_cast<CParseHandlerProjList *>((*this)[1]);
	AddChildFromParseHandler(proj_list_parse_handler);

	// valuesscan child value list begins with third child
	for (ULONG idx = 2; idx < arity; idx++)
	{
		CParseHandlerScalarValuesList *scalar_values_list_parse_handler =
			dynamic_cast<CParseHandlerScalarValuesList *>((*this)[idx]);
		AddChildFromParseHandler(scalar_values_list_parse_handler);
	}

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

// EOF

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