SmartDataObjectPtr.h

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* (c) Copyright 1998-2025 CERN for the benefit of the LHCb and ATLAS collaborations *
*                                                                                   *
* This software is distributed under the terms of the Apache version 2 licence,     *
* copied verbatim in the file "LICENSE".                                            *
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#pragma once
 
#include <GaudiKernel/Kernel.h>
#include <GaudiKernel/StatusCode.h>
#include <string>
 
class SmartDataObjectPtr;
class IDataProviderSvc;
class IRegistry;
class DataObject;

class GAUDI_API SmartDataObjectPtr {
public:
  using AccessFunction = DataObject* (*)( SmartDataObjectPtr* ptr );
  class ObjectLoader {
  public:
    static AccessFunction access();
  };

  class ObjectFinder {
  public:
    static AccessFunction access();
  };
 
public:
  SmartDataObjectPtr( AccessFunction access, IDataProviderSvc* pService, IRegistry* pDir, std::string path )
      : m_dataProvider( pService ), m_pRegistry( pDir ), m_path( std::move( path ) ), m_accessFunc( access ) {}

  SmartDataObjectPtr( const SmartDataObjectPtr& ) = default;

  virtual ~SmartDataObjectPtr() = default;

  virtual SmartDataObjectPtr& operator=( const SmartDataObjectPtr& ) = default;

  operator IRegistry*() { return m_pRegistry; }

  const std::string& path() const { return m_path; }

  IRegistry* directory() { return m_pRegistry; }

  void setService( IDataProviderSvc* svc ) { m_dataProvider = svc; }

  IDataProviderSvc* service() { return m_dataProvider; }

  const StatusCode& getLastError() const { return m_status; }

  DataObject* accessData() { return m_accessFunc( this ); }

  static DataObject* retrieve( SmartDataObjectPtr* ptr ) { return ptr->retrieveObject(); }

  static DataObject* find( SmartDataObjectPtr* ptr ) { return ptr->findObject(); }

  static DataObject* update( SmartDataObjectPtr* ptr ) { return ptr->updateObject(); }

  DataObject* retrieveObject();

  DataObject* findObject();

  DataObject* updateObject();
 
protected:
  StatusCode find( IRegistry* pDirectory, std::string_view path, DataObject*& refpObject );

  StatusCode find( std::string_view fullPath, DataObject*& refpObject );

  StatusCode retrieve( IRegistry* pDirectory, std::string_view path, DataObject*& refpObject );
  StatusCode retrieve( std::string_view fullPath, DataObject*& refpObject );

  StatusCode update( IRegistry* pDirectory );
  StatusCode update( std::string_view fullPath );
 
protected:
  mutable IDataProviderSvc* m_dataProvider = nullptr;
  mutable IRegistry* m_pRegistry = nullptr;
  mutable StatusCode m_status = StatusCode::SUCCESS;
  std::string m_path;
  AccessFunction m_accessFunc = nullptr;
};