ContainerId.h

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/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/

 
 
#ifndef COLUMNAR_CORE_CONTAINER_ID_H
#define COLUMNAR_CORE_CONTAINER_ID_H
 
#include <ColumnarCore/ColumnarDef.h>
#include <ColumnarInterfaces/ColumnInfo.h>
#include <ColumnarInterfaces/ColumnarDef.h>
#include <xAODCore/CLASS_DEF.h>
 
class EventContext;
 
namespace columnar
{
 
  namespace detail
  {
    template<typename T>
    CLID clidForType ()
    {
#ifdef __CLING__
      return 0;
#else
      return ClassID_traits<T>::ID();
#endif
    }
  }
 

  template<typename ObjectType,typename ContainerType>
  struct RegularContainerId
  {
    static constexpr bool isContainerId = true;

    static constexpr bool regularObjectId = true;

    static constexpr bool variantObjectId = false;

    static constexpr bool regularColumnAccessorArray = true;

    static constexpr bool isMutable = false;

    static constexpr bool perEventRange = true;

    static constexpr bool perEventId = false;

    using xAODObjectIdType = const ObjectType;

    using xAODObjectRangeType = const ContainerType;

    using xAODElementLinkType = ContainerType;

    static CLID containerClid ()
    {
      return detail::clidForType<ContainerType> ();
    }
  };

  template<typename CI>
    requires (CI::isContainerId && CI::regularObjectId)
  struct MutableContainerId : public CI
  {
    static constexpr bool isMutable = true;
    using constId = CI;

    using xAODObjectIdType = std::remove_const_t<typename CI::xAODObjectIdType>;

    using xAODObjectRangeType = std::remove_const_t<typename CI::xAODObjectRangeType>;
  };
 
  // including this here, since everyone needs EventContextId/EventContextRange
  struct EventContextDef : RegularContainerId<EventContext,EventContext>
  {
    static constexpr std::string_view idName = eventContextCIName;
 
    // disable retrieve as either ObjectId or ObjectRange, the event
    // context will always be passed into tool code by the caller
    static constexpr bool perEventRange = false;
    static constexpr bool perEventId = false;
  };

  template<typename CI>
  concept ContainerIdConcept = CI::isContainerId;
  template<typename CI>
  concept RegularContainerIdConcept = CI::isContainerId && CI::regularObjectId;
 
  // forward declarations of columnar core classes for which I often
  // provide specific aliases for different container ids.
  template<ContainerIdConcept CI,typename CM = ColumnarModeDefault> class ObjectRange;
  template<ContainerIdConcept CI, typename CM = ColumnarModeDefault> class ObjectId;
  template<ContainerIdConcept CI, typename CM = ColumnarModeDefault> class OptObjectId;
  template<ContainerIdConcept CI, typename CM = ColumnarModeDefault> class ObjectLink;
  template<ContainerIdConcept CI,typename CT,ColumnAccessMode CAM,typename CM = ColumnarModeDefault> class AccessorTemplate;
 
 
  using EventContextRange = ObjectRange<EventContextDef>;
  using EventContextId = ObjectId<EventContextDef>;
}
 
#endif