greenplumn CScalarSwitch 源码
greenplumn CScalarSwitch 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/operators/CScalarSwitch.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2012 EMC Corp.
//
// @filename:
// CScalarSwitch.h
//
// @doc:
// Scalar switch operator
//---------------------------------------------------------------------------
#ifndef GPOPT_CScalarSwitch_H
#define GPOPT_CScalarSwitch_H
#include "gpos/base.h"
#include "gpopt/base/CDrvdProp.h"
#include "gpopt/operators/CScalar.h"
namespace gpopt
{
using namespace gpos;
//---------------------------------------------------------------------------
// @class:
// CScalarSwitch
//
// @doc:
// Scalar switch operator. This corresponds to SQL case statments in the form
// (case expr when expr1 then ret1 when expr2 then ret2 ... else retdef end)
// The switch operator is represented as follows:
// Switch
// |-- expr1
// |-- SwitchCase
// | |-- expr1
// | +-- ret1
// |-- SwitchCase
// | |-- expr2
// | +-- ret2
// :
// +-- retdef
//
//---------------------------------------------------------------------------
class CScalarSwitch : public CScalar
{
private:
// return type
IMDId *m_mdid_type;
// is operator return type BOOL?
BOOL m_fBoolReturnType;
public:
CScalarSwitch(const CScalarSwitch &) = delete;
// ctor
CScalarSwitch(CMemoryPool *mp, IMDId *mdid_type);
// dtor
~CScalarSwitch() override;
// ident accessors
EOperatorId
Eopid() const override
{
return EopScalarSwitch;
}
// return a string for operator name
const CHAR *
SzId() const override
{
return "CScalarSwitch";
}
// the type of the scalar expression
IMDId *
MdidType() const override
{
return m_mdid_type;
}
// 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 true;
}
// return a copy of the operator with remapped columns
COperator *
PopCopyWithRemappedColumns(CMemoryPool *, //mp,
UlongToColRefMap *, //colref_mapping,
BOOL //must_exist
) override
{
return PopCopyDefault();
}
// boolean expression evaluation
EBoolEvalResult
Eber(ULongPtrArray *pdrgpulChildren) const override
{
return EberNullOnAllNullChildren(pdrgpulChildren);
}
// conversion function
static CScalarSwitch *
PopConvert(COperator *pop)
{
GPOS_ASSERT(nullptr != pop);
GPOS_ASSERT(EopScalarSwitch == pop->Eopid());
return dynamic_cast<CScalarSwitch *>(pop);
}
}; // class CScalarSwitch
} // namespace gpopt
#endif // !GPOPT_CScalarSwitch_H
// EOF
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