//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2014 VMware, Inc. or its affiliates.
//
//	@filename:
//		CMDProviderMemory.h
//
//	@doc:
//		Memory-based provider of metadata objects.
//---------------------------------------------------------------------------



#ifndef GPMD_CMDProviderMemory_H
#define GPMD_CMDProviderMemory_H

#include "gpos/base.h"
#include "gpos/string/CWStringDynamic.h"

#include "naucrates/md/IMDCacheObject.h"
#include "naucrates/md/IMDId.h"
#include "naucrates/md/IMDProvider.h"

namespace gpmd
{
using namespace gpos;
using namespace gpnaucrates;

//---------------------------------------------------------------------------
//	@class:
//		CMDProviderMemory
//
//	@doc:
//		Memory-based provider of metadata objects.
//
//---------------------------------------------------------------------------
class CMDProviderMemory : public IMDProvider
{
protected:
	// hash map of serialized MD objects indexed by their MD id
	using MDIdToSerializedMDIdMap =
		CHashMap<IMDId, CWStringDynamic, IMDId::MDIdHash, IMDId::MDIdCompare,
				 CleanupRelease, CleanupDelete>;

	// metadata objects indexed by their metadata id
	MDIdToSerializedMDIdMap *m_mdmap;

	// load MD objects in the hash map
	void LoadMetadataObjectsFromArray(CMemoryPool *mp,
									  IMDCacheObjectArray *mdcache_obj_array);

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

public:
	// ctor
	CMDProviderMemory(CMemoryPool *mp, IMDCacheObjectArray *mdcache_obj_array);

	// ctor
	CMDProviderMemory(CMemoryPool *mp, const CHAR *file_name);

	//dtor
	~CMDProviderMemory() override;

	// returns the DXL string of the requested metadata object
	CWStringBase *GetMDObjDXLStr(CMemoryPool *mp, CMDAccessor *md_accessor,
								 IMDId *mdid) const override;

	// returns the requested metadata object
	IMDCacheObject *GetMDObj(CMemoryPool *mp, CMDAccessor *md_accessor,
							 IMDId *mdid,
							 IMDCacheObject::Emdtype mdtype) const override;

	// return the mdid for the specified system id and type
	IMDId *MDId(CMemoryPool *mp, CSystemId sysid,
				IMDType::ETypeInfo type_info) const override;
};
}  // namespace gpmd



#endif	// !GPMD_CMDProviderMemory_H

// EOF