SGIterator.h

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// This file's extension implies that it's C, but it's really -*- C++ -*-.
/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
 
 
#ifndef STOREGATE_SGITERATOR_H
#define STOREGATE_SGITERATOR_H
 
 
#include "StoreGate/exceptions.h"
#include "SGTools/DataProxy.h"
#include "SGTools/DataProxy_cast.h"
#include "SGTools/ProxyMap.h"
#include "AthenaKernel/IProxyDict.h"
#include <boost/iterator/iterator_facade.hpp>
#include <iterator>
#include <concepts>
class SGImplSvc;
 
 
namespace SG {
 
 
namespace detail {

template <class ITERATOR>
concept DataProxyIterator =
  std::bidirectional_iterator<ITERATOR> && std::same_as<typename std::iterator_traits<ITERATOR>::value_type, DataProxy*>;
 

class IteratorBase {
protected:
  // Required for boost iterator adapter.
  friend class boost::iterator_core_access;
 
  // To access setState.
  friend class ::SGImplSvc;
 

  IteratorBase() = default;
 

  explicit IteratorBase (SG::ConstProxyIterator itr,
                         SG::ConstProxyIterator itrEnd,
                         bool isConst);
 

  template <DataProxyIterator ITERATOR>
  explicit IteratorBase (ITERATOR itr, ITERATOR itrEnd, bool isConst);
 

  IteratorBase (const IteratorBase& other);
 

  ~IteratorBase();
 

  IteratorBase& operator= (const IteratorBase& other);
 
    
  StatusCode setState (SG::ConstProxyIterator itr,
                       SG::ConstProxyIterator itrEnd,
                       bool isConst);
 
  
  template <DataProxyIterator ITERATOR>
  StatusCode setState (ITERATOR itr, ITERATOR itrEnd, bool isConst);
 

  void increment();
 

  bool eql(const IteratorBase& rhs) const;
 

  void const_check() const;
 
 
public:
  DataProxy* proxy() const;
 

  const std::string& key() const;
 
 
private:
  void addRef();
 

  void release();
 

  std::vector<SG::DataProxy*> m_proxies;
};
 
 
} //end ns detail
 

class TypelessIterator
  : public detail::IteratorBase,
    public boost::iterator_facade<
      TypelessIterator, 
      DataProxy*,
      boost::forward_traversal_tag,
      DataProxy*>
{
public:
  using detail::IteratorBase::IteratorBase;
 

  TypelessIterator() = default;
 

  explicit TypelessIterator (SG::ConstProxyIterator itr,
                             SG::ConstProxyIterator itrEnd);
 

  template <detail::DataProxyIterator ITERATOR>
  explicit TypelessIterator (ITERATOR itr, ITERATOR itrEnd);
 

  StatusCode setState (SG::ConstProxyIterator itr,
                       SG::ConstProxyIterator itrEnd);
 

  template <detail::DataProxyIterator ITERATOR>
  StatusCode setState (ITERATOR itr, ITERATOR itrEnd);
 
 
private:
  // Required for boost iterator adapter.
  friend class boost::iterator_core_access;
  //INHERITED: void increment();
 

  bool equal(const TypelessIterator& rhs) const;
 

  DataProxy* dereference() const;
};
 

template <class DATA>
class ConstIterator
  : public detail::IteratorBase, 
    public boost::iterator_facade<
      ConstIterator<DATA>, 
      const DATA,
      boost::forward_traversal_tag > 
{
public:
  ConstIterator();
 

  explicit ConstIterator (SG::ConstProxyIterator itr,
                          SG::ConstProxyIterator itrEnd);
 

  StatusCode setState (SG::ConstProxyIterator itr,
                       SG::ConstProxyIterator itrEnd);
 
 
private:
  // Required for boost iterator adapter.
  friend class boost::iterator_core_access;
  // INHERITED: void increment();
 

  bool equal (const ConstIterator& rhs) const;
 

  const DATA& dereference() const;
};
 

template <class DATA>
class Iterator
  : public detail::IteratorBase, 
    public boost::iterator_facade<
      Iterator<DATA>, 
     DATA,
     boost::forward_traversal_tag > 
{
public:
  Iterator();
 

  explicit Iterator (SG::ConstProxyIterator itr,
                     SG::ConstProxyIterator itrEnd);
 

  StatusCode setState (SG::ConstProxyIterator itr,
                       SG::ConstProxyIterator itrEnd);
 
 
private:
  // Required for boost iterator adapter.
  friend class boost::iterator_core_access;
  //INHERITED: void increment();
 

  bool equal(const Iterator<DATA>& rhs) const;
 

  DATA& dereference() const;
};
 
 
} // namespace SG
 
 
#include "StoreGate/SGIterator.icc"
 
 
#endif