T_AthenaPoolLegacyCnv.h

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/*
  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
*/
 
#ifndef ATHENAPOOLCNVSVC_T_ATHENAPOOLLEGACYCNV_H
#define ATHENAPOOLCNVSVC_T_ATHENAPOOLLEGACYCNV_H

 
#include "T_AthenaPoolCustomCnv.h"

template<class TRANS, class PERS, class LEGACY>
class T_AthenaPoolLegacyCnv : public T_AthenaPoolCustomCnv< TRANS, PERS >
{
   typedef T_AthenaPoolCustomCnv<TRANS, PERS>    BaseCnv;
   typedef T_AthenaPoolCustomCnv<TRANS, LEGACY>  BaseLegacyCnv;
 
   // define an internal AthenaPool converter that will create the old representation LEGACY
   class LegacyCnv : public BaseLegacyCnv
   {
      T_AthenaPoolLegacyCnv      *m_ownerCnv;
   public:
      using BaseLegacyCnv::initialize;
      using BaseLegacyCnv::DataObjectToPool;
      LegacyCnv( ISvcLocator* svcloc, T_AthenaPoolLegacyCnv *owner )
         : BaseLegacyCnv( svcloc ), m_ownerCnv( owner )
      {}
 
      // forward createPersistent() request to the main converter, where the user
      // provides createLegacy() method to do that
      virtual LEGACY*   createPersistent( TRANS* transCont ) override final {
         return m_ownerCnv->createLegacy( transCont );
      }
      // unused virtual method that still needs to be defined 
      virtual TRANS*    createTransient() override final { return nullptr; };
   };
 
   // this is the converter that knows how to produce and manage LEGACY representations
   std::unique_ptr<LegacyCnv>   m_oldAPCnv;
 
public:
   T_AthenaPoolLegacyCnv( ISvcLocator* svcloc ) : BaseCnv(svcloc)  { }
   
protected:
   virtual StatusCode DataObjectToPool(IOpaqueAddress* pAddr, DataObject* pObj) override final {
      if( writingLegacy() ) {
         if( !m_oldAPCnv ) {
            m_oldAPCnv = std::make_unique<LegacyCnv>( this->serviceLocator() , this );
            StatusCode sc = m_oldAPCnv->initialize();
            if( !sc.isSuccess() ) {
               ATH_MSG_ERROR("Failed to initialize old converter");
               return sc;
            }
         }
         return m_oldAPCnv->DataObjectToPool( pAddr, pObj );
      }
      return BaseCnv::DataObjectToPool( pAddr, pObj );
   }
   
   virtual TRANS*       createTransient () override = 0;
   virtual PERS*        createPersistent( TRANS* ) override = 0;

   virtual LEGACY*      createLegacy( TRANS* ) = 0;
   virtual bool         writingLegacy() = 0;
};
 
 
#endif