greenplumn CParseHandlerDefaultValueExpr 代码
文件路径：/src/backend/gporca/libnaucrates/src/parser/CParseHandlerDefaultValueExpr.cpp
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2011 Greenplum, Inc.
/
/ @filename:
/ CParseHandlerDefaultValueExpr.cpp
/
/ @doc:
/ Implementation of the SAX parse handler class for parsing default value expression
/---------------------------------------------------------------------------
#include "naucrates/dxl/parser/CParseHandlerDefaultValueExpr.h"
#include "naucrates/dxl/parser/CParseHandlerFactory.h"
#include "naucrates/dxl/parser/CParseHandlerScalarOp.h"
using namespace gpdxl;
XERCES_CPP_NAMESPACE_USE
/---------------------------------------------------------------------------
/ @function:
/ CParseHandlerDefaultValueExpr::CParseHandlerDefaultValueExpr
/
/ @doc:
/ Constructor
/
/---------------------------------------------------------------------------
CParseHandlerDefaultValueExpr::CParseHandlerDefaultValueExpr(
CMemoryPool *mp, CParseHandlerManager *parse_handler_mgr,
CParseHandlerBase *parse_handler_root)
: CParseHandlerScalarOp(mp, parse_handler_mgr, parse_handler_root),
is_default_val_started(false)
{
}
/---------------------------------------------------------------------------
/ @function:
/ CParseHandlerDefaultValueExpr::StartElement
/
/ @doc:
/ Processes a Xerces start element event
/
/---------------------------------------------------------------------------
void
CParseHandlerDefaultValueExpr::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(EdxltokenColumnDefaultValue),
element_local_name))
{
/ opening tag for a default expression: assert no other tag has been seen yet
GPOS_ASSERT(!is_default_val_started);
is_default_val_started = true;
}
else
{
GPOS_ASSERT(is_default_val_started);
/ install a scalar op parse handler to parse the expression
CParseHandlerBase *scalar_op_parse_handler =
CParseHandlerFactory::GetParseHandler(m_mp, element_local_name,
m_parse_handler_mgr, this);
GPOS_ASSERT(nullptr != scalar_op_parse_handler);
/ activate the child parse handler
m_parse_handler_mgr->ActivateParseHandler(scalar_op_parse_handler);
/ pass the startElement message for the specialized parse handler to process
scalar_op_parse_handler->startElement(element_uri, element_local_name,
element_qname, attrs);
/ store parse handlers
this->Append(scalar_op_parse_handler);
}
}
/---------------------------------------------------------------------------
/ @function:
/ CParseHandlerDefaultValueExpr::EndElement
/
/ @doc:
/ Processes a Xerces end element event
/
/---------------------------------------------------------------------------
void
CParseHandlerDefaultValueExpr::EndElement(const XMLCh *const, / element_uri,
const XMLCh *const element_local_name,
const XMLCh *const / element_qname
)
{
if (0 != XMLString::compareString(
CDXLTokens::XmlstrToken(EdxltokenColumnDefaultValue),
element_local_name))
{
CWStringDynamic *str = CDXLUtils::CreateDynamicStringFromXMLChArray(
m_parse_handler_mgr->GetDXLMemoryManager(), element_local_name);
GPOS_RAISE(gpdxl::ExmaDXL, gpdxl::ExmiDXLUnexpectedTag,
str->GetBuffer());
}
if (0 < this->Length())
{
GPOS_ASSERT(1 == this->Length());
/ get node for default value expression from child parse handler
CParseHandlerScalarOp *child_parse_handler =
dynamic_cast<CParseHandlerScalarOp *>((*this)[0]);
m_dxl_node = child_parse_handler->CreateDXLNode();
m_dxl_node->AddRef();
}
/ deactivate handler
m_parse_handler_mgr->DeactivateHandler();
}
/ EOF
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