greenplumn CConstExprEvaluatorDXL 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/eval/CConstExprEvaluatorDXL.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2014 VMware, Inc. or its affiliates.
/
/ @filename:
/ CConstExprEvaluatorDXL.h
/
/ @doc:
/ Constant expression evaluator implementation that delegates to a DXL evaluator
/
/ @owner:
/
/
/ @test:
/
/---------------------------------------------------------------------------
#ifndef GPOPT_CConstExprEvaluatorDXL_H
#define GPOPT_CConstExprEvaluatorDXL_H
#include "gpos/base.h"
#include "gpopt/base/CColRef.h"
#include "gpopt/eval/IConstExprEvaluator.h"
#include "gpopt/translate/CTranslatorDXLToExpr.h"
#include "gpopt/translate/CTranslatorExprToDXL.h"
#include "naucrates/dxl/operators/CDXLNode.h"
#include "naucrates/md/CMDName.h"
/ forward declaration
namespace gpos
{
class CMemoryPool;
}
namespace gpopt
{
class CExpression;
class CMDAccessor;
class IConstDXLNodeEvaluator;
/---------------------------------------------------------------------------
/ @class:
/ CConstExprEvaluatorDXL
/
/ @doc:
/ Constant expression evaluator implementation that delegates to a DXL evaluator
/
/---------------------------------------------------------------------------
class CConstExprEvaluatorDXL : public IConstExprEvaluator
{
private:
/ evaluates expressions represented as DXL, not owned
IConstDXLNodeEvaluator *m_pconstdxleval;
/ translates CExpression's to DXL which can then be sent to the evaluator
CTranslatorExprToDXL m_trexpr2dxl;
/ translates DXL coming from the evaluator back to CExpression
CTranslatorDXLToExpr m_trdxl2expr;
public:
CConstExprEvaluatorDXL(const CConstExprEvaluatorDXL &) = delete;
/ ctor
CConstExprEvaluatorDXL(CMemoryPool *mp, CMDAccessor *md_accessor,
IConstDXLNodeEvaluator *pconstdxleval);
/ dtor
~CConstExprEvaluatorDXL() override;
/ evaluate the given expression and return the result as a new expression
/ caller takes ownership of returned expression
CExpression *PexprEval(CExpression *pexpr) override;
/ Returns true iff the evaluator can evaluate expressions
BOOL FCanEvalExpressions() override;
};
} / namespace gpopt
#endif / !GPOPT_CConstExprEvaluatorDXL_H
/ EOF
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