CTranslatorDXLToScalar.h

//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2011 Greenplum, Inc.
//
//	@filename:
//		CTranslatorDXLToScalar.h
//
//	@doc:
//		Class providing methods for translating from DXL Scalar Node to
//		GPDB's Expr.
//
//	@test:
//
//
//---------------------------------------------------------------------------

#ifndef GPDXL_CTranslatorDXLToScalar_H
#define GPDXL_CTranslatorDXLToScalar_H


#include "gpopt/translate/CMappingColIdVar.h"
#include "gpopt/translate/CContextDXLToPlStmt.h"
#include "gpopt/translate/CMappingElementColIdParamId.h"

#include "gpos/base.h"

#include "naucrates/dxl/operators/CDXLNode.h"
#include "naucrates/dxl/operators/CDXLDatum.h"
#include "naucrates/dxl/operators/CDXLScalarArrayRefIndexList.h"
#include "naucrates/dxl/operators/CDXLScalarCast.h"

// fwd declarations
namespace gpopt
{
class CMDAccessor;
}

namespace gpmd
{
class IMDId;
}

struct Aggref;
struct BoolExpr;
struct BooleanTest;
struct CaseExpr;
struct Expr;
struct FuncExpr;
struct NullTest;
struct OpExpr;
struct Param;
struct Plan;
struct RelabelType;
struct ScalarArrayOpExpr;
struct Const;
struct List;
struct SubLink;
struct SubPlan;

namespace gpdxl
{
using namespace gpopt;
using namespace gpmd;

//---------------------------------------------------------------------------
//	@class:
//		CTranslatorDXLToScalar
//
//	@doc:
//		Class providing methods for translating from DXL Scalar Node to
//		GPDB's Expr.
//
//---------------------------------------------------------------------------
class CTranslatorDXLToScalar
{
	// shorthand for functions for translating DXL nodes to GPDB expressions
	typedef Expr *(CTranslatorDXLToScalar::*expr_func_ptr)(
		const CDXLNode *dxlnode, CMappingColIdVar *colid_var);

private:
	// pair of DXL op id and translator function
	struct STranslatorElem
	{
		Edxlopid eopid;
		expr_func_ptr translate_func;
	};

	// shorthand for functions for translating DXL nodes to GPDB expressions
	typedef Const *(CTranslatorDXLToScalar::*const_func_ptr)(CDXLDatum *);

	// pair of DXL datum type and translator function
	struct SDatumTranslatorElem
	{
		CDXLDatum::EdxldatumType edxldt;
		const_func_ptr translate_func;
	};

	CMemoryPool *m_mp;

	// meta data accessor
	CMDAccessor *m_md_accessor;

	// The parent plan needed when translating an initplan
	Plan *m_plan;

	// indicates whether a sublink was encountered during translation of the scalar subtree
	BOOL m_has_subqueries;

	// number of segments
	ULONG m_num_of_segments;

	// translate a CDXLScalarArrayComp into a GPDB ScalarArrayOpExpr
	Expr *TranslateDXLScalarArrayCompToScalar(
		const CDXLNode *scalar_array_cmp_node, CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarOpExprToScalar(const CDXLNode *scalar_op_expr_node,
										   CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarDistinctToScalar(
		const CDXLNode *scalar_distinct_cmp_node, CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarBoolExprToScalar(
		const CDXLNode *scalar_bool_expr_node, CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarBooleanTestToScalar(
		const CDXLNode *scalar_boolean_test_node, CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarCastToScalar(
		const CDXLNode *scalar_relabel_type_node, CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarCoerceToDomainToScalar(const CDXLNode *coerce_node,
												   CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarCoerceViaIOToScalar(const CDXLNode *coerce_node,
												CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarArrayCoerceExprToScalar(
		const CDXLNode *coerce_node, CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarNullTestToScalar(
		const CDXLNode *scalar_null_test_node, CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarNullIfToScalar(const CDXLNode *scalar_null_if_node,
										   CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarIfStmtToScalar(const CDXLNode *scalar_if_stmt_node,
										   CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarSwitchToScalar(const CDXLNode *scalar_switch_node,
										   CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarCaseTestToScalar(
		const CDXLNode *scalar_case_test_node, CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarAggrefToScalar(const CDXLNode *aggref_node,
										   CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarWindowRefToScalar(
		const CDXLNode *scalar_winref_node, CMappingColIdVar *colid_var);

	Expr *TranslateDXLScalarFuncExprToScalar(
		const CDXLNode *scalar_func_expr_node, CMappingColIdVar *colid_var);

	// return a GPDB subplan from a DXL subplan
	Expr *TranslateDXLScalarSubplanToScalar(
		const CDXLNode *scalar_sub_plan_node, CMappingColIdVar *colid_var);

	// build subplan node
	SubPlan *TranslateSubplanFromChildPlan(
		Plan *plan_child, SubLinkType slink,
		CContextDXLToPlStmt *dxl_to_plstmt_ctxt);

	// translate subplan test expression
	Expr *TranslateDXLSubplanTestExprToScalar(CDXLNode *test_expr_node,
											  SubLinkType slink,
											  CMappingColIdVar *colid_var,
											  List **param_ids_list);

	// translate subplan parameters
	void TranslateSubplanParams(SubPlan *sub_plan,
								CDXLTranslateContext *dxl_translator_ctxt,
								const CDXLColRefArray *outer_refs,
								CMappingColIdVar *colid_var);

	CHAR *GetSubplanAlias(ULONG plan_id);

	Param *TranslateParamFromMapping(
		const CMappingElementColIdParamId *colid_to_param_id_map);

	// translate a scalar coalesce
	Expr *TranslateDXLScalarCoalesceToScalar(
		const CDXLNode *scalar_coalesce_node, CMappingColIdVar *colid_var);

	// translate a scalar minmax
	Expr *TranslateDXLScalarMinMaxToScalar(const CDXLNode *scalar_min_max_node,
										   CMappingColIdVar *colid_var);

	// translate a scconstval
	Expr *TranslateDXLScalarConstToScalar(const CDXLNode *scalar_const_node,
										  CMappingColIdVar *colid_var);

	// translate an array expression
	Expr *TranslateDXLScalarArrayToScalar(const CDXLNode *scalar_array_node,
										  CMappingColIdVar *colid_var);

	// translate an arrayref expression
	Expr *TranslateDXLScalarArrayRefToScalar(
		const CDXLNode *scalar_array_ref_node, CMappingColIdVar *colid_var);

	// translate an arrayref index list
	List *TranslateDXLArrayRefIndexListToScalar(
		const CDXLNode *index_list_node,
		CDXLScalarArrayRefIndexList::EIndexListBound index_list_bound,
		CMappingColIdVar *colid_var);

	// translate a DML action expression
	Expr *TranslateDXLScalarDMLActionToScalar(const CDXLNode *dml_action_node,
											  CMappingColIdVar *colid_var);


	// translate children of DXL node, and add them to list
	List *TranslateScalarChildren(List *list, const CDXLNode *dxlnode,
								  CMappingColIdVar *colid_var);

	// return the operator return type oid for the given func id.
	OID GetFunctionReturnTypeOid(IMDId *mdid) const;

	// translate dxldatum to GPDB Const
	Const *ConvertDXLDatumToConstOid(CDXLDatum *datum_dxl);
	Const *ConvertDXLDatumToConstInt2(CDXLDatum *datum_dxl);
	Const *ConvertDXLDatumToConstInt4(CDXLDatum *datum_dxl);
	Const *ConvertDXLDatumToConstInt8(CDXLDatum *datum_dxl);
	Const *ConvertDXLDatumToConstBool(CDXLDatum *datum_dxl);
	Const *TranslateDXLDatumGenericToScalar(CDXLDatum *datum_dxl);
	Expr *TranslateRelabelTypeOrFuncExprFromDXL(
		const CDXLScalarCast *scalar_cast, Expr *pexprChild);

	// private copy ctor
	CTranslatorDXLToScalar(const CTranslatorDXLToScalar &);

public:
	struct STypeOidAndTypeModifier
	{
		OID oid_type;
		INT type_modifier;
	};

	// ctor
	CTranslatorDXLToScalar(CMemoryPool *mp, CMDAccessor *md_accessor,
						   ULONG num_segments);

	// translate DXL scalar operator node into an Expr expression
	// This function is called during the translation of DXL->Query or DXL->Query
	Expr *TranslateDXLToScalar(const CDXLNode *scalar_op_node,
							   CMappingColIdVar *colid_var);

	// translate a scalar part default into an Expr
	Expr *TranslateDXLScalarPartDefaultToScalar(
		const CDXLNode *part_default_node, CMappingColIdVar *colid_var);

	// translate a scalar part bound into an Expr
	Expr *TranslateDXLScalarPartBoundToScalar(const CDXLNode *part_bound_node,
											  CMappingColIdVar *colid_var);

	// translate a scalar part bound inclusion into an Expr
	Expr *TranslateDXLScalarPartBoundInclusionToScalar(
		const CDXLNode *part_bound_incl_node, CMappingColIdVar *colid_var);

	// translate a scalar part bound openness into an Expr
	Expr *TranslateDXLScalarPartBoundOpenToScalar(
		const CDXLNode *part_bound_open_node, CMappingColIdVar *colid_var);

	// translate a scalar part list values into an Expr
	Expr *TranslateDXLScalarPartListValuesToScalar(
		const CDXLNode *part_list_values_node, CMappingColIdVar *colid_var);

	// translate a scalar part list null test into an Expr
	Expr *TranslateDXLScalarPartListNullTestToScalar(
		const CDXLNode *part_list_null_test_node, CMappingColIdVar *colid_var);

	// translate a scalar ident into an Expr
	Expr *TranslateDXLScalarIdentToScalar(const CDXLNode *scalar_id_node,
										  CMappingColIdVar *colid_var);

	// translate a scalar comparison into an Expr
	Expr *TranslateDXLScalarCmpToScalar(const CDXLNode *scalar_cmp_node,
										CMappingColIdVar *colid_var);


	// checks if the operator return a boolean result
	static BOOL HasBoolResult(CDXLNode *dxlnode, CMDAccessor *md_accessor);

	// check if the operator is a "true" bool constant
	static BOOL HasConstTrue(CDXLNode *dxlnode, CMDAccessor *md_accessor);

	// check if the operator is a NULL constant
	static BOOL HasConstNull(CDXLNode *dxlnode);

	// are there subqueries in the tree
	BOOL
	HasSubqueries() const
	{
		return m_has_subqueries;
	}

	// translate a DXL datum into GPDB const expression
	Expr *TranslateDXLDatumToScalar(CDXLDatum *datum_dxl);
};
}  // namespace gpdxl
#endif	// !GPDXL_CTranslatorDXLToScalar_H

// EOF