greenplumn IMDProvider 源码
greenplumn IMDProvider 代码
文件路径：/src/backend/gporca/libnaucrates/include/naucrates/md/IMDProvider.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2011 Greenplum, Inc.
//
// @filename:
// IMDProvider.h
//
// @doc:
// Abstract class for retrieving metadata from an external location.
//---------------------------------------------------------------------------
#ifndef GPMD_IMDProvider_H
#define GPMD_IMDProvider_H
#include "gpos/base.h"
#include "gpos/common/CHashMap.h"
#include "gpos/string/CWStringBase.h"
#include "gpos/string/CWStringConst.h"
#include "naucrates/md/IMDFunction.h"
#include "naucrates/md/IMDId.h"
#include "naucrates/md/IMDType.h"
namespace gpmd
{
using namespace gpos;
//---------------------------------------------------------------------------
// @class:
// IMDProvider
//
// @doc:
// Abstract class for retrieving metadata from an external location.
//
//---------------------------------------------------------------------------
class IMDProvider : public CRefCount
{
protected:
// return the mdid for the requested type
static IMDId *GetGPDBTypeMdid(CMemoryPool *mp, CSystemId sysid,
IMDType::ETypeInfo type_info);
public:
~IMDProvider() override = default;
// returns the DXL string of the requested metadata object
virtual CWStringBase *GetMDObjDXLStr(CMemoryPool *mp,
CMDAccessor *md_accessor,
IMDId *mdid) const = 0;
// return the requested metadata object
virtual IMDCacheObject *GetMDObj(CMemoryPool *mp, CMDAccessor *md_accessor,
IMDId *mdid) const = 0;
// return the mdid for the specified system id and type
virtual IMDId *MDId(CMemoryPool *mp, CSystemId sysid,
IMDType::ETypeInfo type_info) const = 0;
};
// arrays of MD providers
using CMDProviderArray = CDynamicPtrArray<IMDProvider, CleanupRelease>;
} // namespace gpmd
#endif // !GPMD_IMDProvider_H
// EOF
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