greenplumn CScalarConst 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/operators/CScalarConst.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2011 EMC Corp.
/
/ @filename:
/ CScalarConst.h
/
/ @doc:
/ An operator class that wraps a scalar constant
/---------------------------------------------------------------------------
#ifndef GPOPT_CScalarConst_H
#define GPOPT_CScalarConst_H
#include "gpos/base.h"
#include "gpopt/base/CColRefSet.h"
#include "gpopt/base/CDrvdProp.h"
#include "gpopt/operators/CScalar.h"
#include "naucrates/base/IDatum.h"
namespace gpopt
{
using namespace gpos;
using namespace gpnaucrates;
/---------------------------------------------------------------------------
/ @class:
/ CScalarConst
/
/ @doc:
/ A wrapper operator for scalar constants
/
/---------------------------------------------------------------------------
class CScalarConst : public CScalar
{
private:
/ constant
IDatum *m_pdatum;
public:
CScalarConst(const CScalarConst &) = delete;
/ ctor
CScalarConst(CMemoryPool *mp, IDatum *datum);
/ dtor
~CScalarConst() override;
/ identity accessor
EOperatorId
Eopid() const override
{
return EopScalarConst;
}
/ return a string for operator name
const CHAR *
SzId() const override
{
return "CScalarConst";
}
/ accessor of contained constant
IDatum *
GetDatum() const
{
return m_pdatum;
}
/ operator specific hash function
ULONG HashValue() const override;
/ match function
BOOL Matches(COperator *pop) const override;
/ sensitivity to order of inputs
BOOL
FInputOrderSensitive() const override
{
return false;
}
/ return a copy of the operator with remapped columns
COperator *
PopCopyWithRemappedColumns(CMemoryPool *, /mp,
UlongToColRefMap *, /colref_mapping,
BOOL /must_exist
) override
{
return PopCopyDefault();
}
/ conversion function
static CScalarConst *
PopConvert(COperator *pop)
{
GPOS_ASSERT(nullptr != pop);
GPOS_ASSERT(EopScalarConst == pop->Eopid());
return dynamic_cast<CScalarConst *>(pop);
}
/ the type of the scalar expression
IMDId *MdidType() const override;
INT TypeModifier() const override;
/ boolean expression evaluation
EBoolEvalResult Eber(ULongPtrArray *pdrgpulChildren) const override;
/ print
IOstream &OsPrint(IOstream &) const override;
/ is the given expression a scalar cast of a constant
static BOOL FCastedConst(CExpression *pexpr);
/ extract the constant from the given constant expression or a casted constant expression.
/ Else return NULL.
static CScalarConst *PopExtractFromConstOrCastConst(CExpression *pexpr);
}; / class CScalarConst
} / namespace gpopt
#endif / !GPOPT_CScalarConst_H
/ EOF
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