//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2009 Greenplum, Inc.
//
//	@filename:
//		CScalarIdent.h
//
//	@doc:
//		Scalar column identifier
//---------------------------------------------------------------------------
#ifndef GPOPT_CScalarIdent_H
#define GPOPT_CScalarIdent_H

#include "gpos/base.h"

#include "gpopt/base/CDrvdProp.h"
#include "gpopt/operators/CScalar.h"

namespace gpopt
{
using namespace gpos;

//---------------------------------------------------------------------------
//	@class:
//		CScalarIdent
//
//	@doc:
//		scalar identifier operator
//
//---------------------------------------------------------------------------
class CScalarIdent : public CScalar
{
private:
	// column
	const CColRef *m_pcr;


public:
	CScalarIdent(const CScalarIdent &) = delete;

	// ctor
	CScalarIdent(CMemoryPool *mp, const CColRef *colref)
		: CScalar(mp), m_pcr(colref)
	{
	}

	// dtor
	~CScalarIdent() override = default;

	// ident accessors
	EOperatorId
	Eopid() const override
	{
		return EopScalarIdent;
	}

	// return a string for operator name
	const CHAR *
	SzId() const override
	{
		return "CScalarIdent";
	}

	// accessor
	const CColRef *
	Pcr() const
	{
		return m_pcr;
	}

	// operator specific hash function
	ULONG HashValue() const override;

	static ULONG
	HashValue(const CScalarIdent *pscalarIdent)
	{
		return CColRef::HashValue(pscalarIdent->Pcr());
	}

	static BOOL
	Equals(const CScalarIdent *left, const CScalarIdent *right)
	{
		return CColRef::Equals(left->Pcr(), right->Pcr());
	}

	// match function
	BOOL Matches(COperator *pop) const override;

	// sensitivity to order of inputs
	BOOL FInputOrderSensitive() const override;

	// return a copy of the operator with remapped columns
	COperator *PopCopyWithRemappedColumns(CMemoryPool *mp,
										  UlongToColRefMap *colref_mapping,
										  BOOL must_exist) override;


	// return locally used columns
	CColRefSet *
	PcrsUsed(CMemoryPool *mp,
			 CExpressionHandle &  // exprhdl

			 ) override
	{
		CColRefSet *pcrs = GPOS_NEW(mp) CColRefSet(mp);
		pcrs->Include(m_pcr);

		return pcrs;
	}

	// conversion function
	static CScalarIdent *
	PopConvert(COperator *pop)
	{
		GPOS_ASSERT(nullptr != pop);
		GPOS_ASSERT(EopScalarIdent == pop->Eopid());

		return dynamic_cast<CScalarIdent *>(pop);
	}

	// the type of the scalar expression
	IMDId *MdidType() const override;

	// the type modifier of the scalar expression
	INT TypeModifier() const override;

	// print
	IOstream &OsPrint(IOstream &os) const override;

	// is the given expression a scalar cast of a scalar identifier
	static BOOL FCastedScId(CExpression *pexpr);

	// is the given expression a scalar cast of given scalar identifier
	static BOOL FCastedScId(CExpression *pexpr, CColRef *colref);

	// is the given expression a scalar func allowed for Partition selection of given scalar identifier
	static BOOL FAllowedFuncScId(CExpression *pexpr);

	// is the given expression a scalar func allowed for Partition selection of given scalar identifier
	static BOOL FAllowedFuncScId(CExpression *pexpr, CColRef *colref);

};	// class CScalarIdent

}  // namespace gpopt


#endif	// !GPOPT_CScalarIdent_H

// EOF