greenplumn CParseHandlerSequence 源码

greenplumn CParseHandlerSequence 代码

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

//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2012 EMC Corp.
//
//	@filename:
//		CParseHandlerSequence.cpp
//
//	@doc:
//		Implementation of the SAX parse handler class for parsing sequence
//		operators
//---------------------------------------------------------------------------

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

#include "naucrates/dxl/operators/CDXLOperatorFactory.h"
#include "naucrates/dxl/operators/CDXLPhysicalDynamicTableScan.h"
#include "naucrates/dxl/operators/CDXLPhysicalSequence.h"
#include "naucrates/dxl/parser/CParseHandlerFactory.h"
#include "naucrates/dxl/parser/CParseHandlerFilter.h"
#include "naucrates/dxl/parser/CParseHandlerProjList.h"
#include "naucrates/dxl/parser/CParseHandlerProperties.h"
#include "naucrates/dxl/parser/CParseHandlerTableDescr.h"
#include "naucrates/dxl/parser/CParseHandlerUtils.h"

using namespace gpdxl;


XERCES_CPP_NAMESPACE_USE

//---------------------------------------------------------------------------
//	@function:
//		CParseHandlerSequence::CParseHandlerSequence
//
//	@doc:
//		Constructor
//
//---------------------------------------------------------------------------
CParseHandlerSequence::CParseHandlerSequence(
	CMemoryPool *mp, CParseHandlerManager *parse_handler_mgr,
	CParseHandlerBase *parse_handler_root)
	: CParseHandlerPhysicalOp(mp, parse_handler_mgr, parse_handler_root),
	  m_is_inside_sequence(false)
{
}


//---------------------------------------------------------------------------
//	@function:
//		CParseHandlerSequence::StartElement
//
//	@doc:
//		Invoked by Xerces to process an opening tag
//
//---------------------------------------------------------------------------
void
CParseHandlerSequence::StartElement(const XMLCh *const element_uri,
									const XMLCh *const element_local_name,
									const XMLCh *const element_qname,
									const Attributes &attrs)
{
	if (!m_is_inside_sequence &&
		0 == XMLString::compareString(
				 CDXLTokens::XmlstrToken(EdxltokenPhysicalSequence),
				 element_local_name))
	{
		// new sequence operator
		// 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 child parse handlers in array
		this->Append(prop_parse_handler);
		this->Append(proj_list_parse_handler);
		m_is_inside_sequence = true;
	}
	else
	{
		// child of the sequence operator
		CParseHandlerBase *child_parse_handler =
			CParseHandlerFactory::GetParseHandler(m_mp, element_local_name,
												  m_parse_handler_mgr, this);
		m_parse_handler_mgr->ActivateParseHandler(child_parse_handler);
		this->Append(child_parse_handler);
		child_parse_handler->startElement(element_uri, element_local_name,
										  element_qname, attrs);
	}
}

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

	// construct node from the created child nodes
	CParseHandlerProperties *prop_parse_handler =
		dynamic_cast<CParseHandlerProperties *>((*this)[0]);

	CDXLPhysicalSequence *dxl_op = GPOS_NEW(m_mp) CDXLPhysicalSequence(m_mp);
	m_dxl_node = GPOS_NEW(m_mp) CDXLNode(m_mp, dxl_op);

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

	// add project list
	CParseHandlerProjList *proj_list_parse_handler =
		dynamic_cast<CParseHandlerProjList *>((*this)[1]);
	GPOS_ASSERT(nullptr != proj_list_parse_handler);
	AddChildFromParseHandler(proj_list_parse_handler);

	const ULONG size = this->Length();
	// add constructed children from child parse handlers
	for (ULONG idx = 2; idx < size; idx++)
	{
		CParseHandlerPhysicalOp *child_parse_handler =
			dynamic_cast<CParseHandlerPhysicalOp *>((*this)[idx]);
		GPOS_ASSERT(nullptr != child_parse_handler);
		AddChildFromParseHandler(child_parse_handler);
	}

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

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

// EOF

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