greenplumn CWindowFrame 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/base/CWindowFrame.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2012 EMC Corp.
/
/ @filename:
/ CWindowFrame.h
/
/ @doc:
/ Description of window frame
/---------------------------------------------------------------------------
#ifndef GPOPT_CWindowFrame_H
#define GPOPT_CWindowFrame_H
#include "gpos/base.h"
#include "gpos/common/CRefCount.h"
#include "gpopt/base/CColRef.h"
#include "gpopt/base/CPropSpec.h"
namespace gpopt
{
/ type definition of corresponding dynamic pointer array
class CWindowFrame;
using CWindowFrameArray = CDynamicPtrArray<CWindowFrame, CleanupRelease>;
using namespace gpos;
/---------------------------------------------------------------------------
/ @class:
/ CWindowFrame
/
/ @doc:
/ Description of window frame
/
/---------------------------------------------------------------------------
class CWindowFrame : public CRefCount, public DbgPrintMixin<CWindowFrame>
{
public:
/ specification method
enum EFrameSpec
{
EfsRows, / frame is specified using Rows construct
EfsRange, / frame is specified using Range construct
EfsSentinel
};
/ types of frame boundary
enum EFrameBoundary
{
EfbUnboundedPreceding, / boundary is unlimited preceding current row
EfbBoundedPreceding, / boundary is limited preceding current row
EfbCurrentRow, / boundary is set to current row
EfbUnboundedFollowing, / boundary is unlimited following current row
EfbBoundedFollowing, / boundary is limited following current row
EfbDelayedBoundedPreceding, / boundary is delayed preceding current row
EfbDelayedBoundedFollowing, / boundary is delayed following current row
EfbSentinel
};
/ possible exclusion strategies
enum EFrameExclusionStrategy
{
EfesNone, / no exclusion
EfesNulls, / exclude nulls
EfesCurrentRow, / exclude current row
EfseMatchingOthers, / exclude other rows matching current row
EfesTies, / exclude other matching rows and current row
EfesSentinel
};
private:
/ specification method
const EFrameSpec m_efs{EfsRange};
/ type of leading edge
const EFrameBoundary m_efbLeading{EfbUnboundedPreceding};
/ type of trailing edge
const EFrameBoundary m_efbTrailing{EfbCurrentRow};
/ scalar value of leading edge, memory owned by this class
CExpression *m_pexprLeading{nullptr};
/ scalar value of trailing edge, memory owned by this class
CExpression *m_pexprTrailing{nullptr};
/ exclusion strategy
const EFrameExclusionStrategy m_efes{EfesNone};
/ columns used by frame edges
CColRefSet *m_pcrsUsed{nullptr};
/ singelton empty frame -- used with any unspecified window function frame
static const CWindowFrame m_wfEmpty;
/ private dummy ctor used to create empty frame
CWindowFrame();
public:
CWindowFrame(const CWindowFrame &) = delete;
/ ctor
CWindowFrame(CMemoryPool *mp, EFrameSpec efs, EFrameBoundary efbLeading,
EFrameBoundary efbTrailing, CExpression *pexprLeading,
CExpression *pexprTrailing, EFrameExclusionStrategy efes);
/ dtor
~CWindowFrame() override;
/ specification
EFrameSpec
Efs() const
{
return m_efs;
}
/ type of leading edge
EFrameBoundary
EfbLeading() const
{
return m_efbLeading;
}
/ type of trailing edge
EFrameBoundary
EfbTrailing() const
{
return m_efbTrailing;
}
/ scalar value of leading edge
CExpression *
PexprLeading() const
{
return m_pexprLeading;
}
/ scalar value of trailing edge
CExpression *
PexprTrailing() const
{
return m_pexprTrailing;
}
/ exclusion strategy
EFrameExclusionStrategy
Efes() const
{
return m_efes;
}
/ matching function
BOOL Matches(const CWindowFrame *pwf) const;
/ hash function
virtual ULONG HashValue() const;
/ return a copy of the window frame with remapped columns
virtual CWindowFrame *PwfCopyWithRemappedColumns(
CMemoryPool *mp, UlongToColRefMap *colref_mapping, BOOL must_exist);
/ return columns used by frame edges
CColRefSet *
PcrsUsed() const
{
return m_pcrsUsed;
}
/ print
IOstream &OsPrint(IOstream &os) const;
/ matching function over frame arrays
static BOOL Equals(const CWindowFrameArray *pdrgpwfFirst,
const CWindowFrameArray *pdrgpwfSecond);
/ combine hash values of a maximum number of entries
static ULONG HashValue(const CWindowFrameArray *pdrgpwfFirst,
ULONG ulMaxSize);
/ print array of window frame objects
static IOstream &OsPrint(IOstream &os, const CWindowFrameArray *pdrgpwf);
/ check if a given window frame is empty
static BOOL
IsEmpty(CWindowFrame *pwf)
{
return pwf == &m_wfEmpty;
}
/ return pointer to singleton empty window frame
static const CWindowFrame *
PwfEmpty()
{
return &m_wfEmpty;
}
}; / class CWindowFrame
} / namespace gpopt
#endif / !GPOPT_CWindowFrame_H
/ EOF
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