greenplumn CScalarConst 源码
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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