ObjectColumnXAOD.icc

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/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/
 
/// @author Nils Krumnack
 
 
#include <ColumnarCore/ColumnarTool.h>
#include <ColumnarCore/ObjectId.h>
#include <ColumnarCore/ObjectRange.h>
#include <ColumnarCore/ContainerId.h>
#include <cassert>
 
namespace columnar
{
  template<ContainerIdConcept CI>
  class AccessorTemplate<CI,ObjectColumn,ColumnAccessMode::input,ColumnarModeXAOD> final
  {
    /// Common Public Members
    /// =====================
  public:
 
    static_assert (CI::perEventRange || CI::perEventId, "ObjectColumn can only be used with per-event ranges or IDs");
 
    using CM = ColumnarModeXAOD;
 
    AccessorTemplate () = default;
 
    AccessorTemplate (ColumnarTool<CM>& columnBase,
                      const std::string& name,
                      ColumnInfo&& /*info*/ = {})
      : m_columnBase (&columnBase), m_key (name)
    {
    }
 
    ObjectRange<CI,CM> operator() (ObjectId<ContainerId::eventContext,CM> /*eventId*/) const
      requires (CI::perEventRange)
    {
      return ObjectRange<CI,CM> (retrieveObject ());
    }
 
    ObjectRange<CI,CM> operator() (ObjectRange<ContainerId::eventContext,CM> /*eventRange*/) const
      requires (CI::perEventRange)
    {
      return ObjectRange<CI,CM> (retrieveObject ());
    }
 
    ObjectId<CI,CM> operator() (ObjectId<ContainerId::eventContext,CM> /*eventId*/) const
      requires (CI::perEventId)
    {
      return ObjectId<CI,CM> (retrieveObject ());
    }
 
    ObjectRange<CI,CM> operator() (ObjectRange<ContainerId::eventContext,CM> /*eventRange*/) const
      requires (CI::perEventId)
    {
      return ObjectRange<CI,CM> (retrieveObject ());
    }
 
    [[nodiscard]] bool isAvailable (ObjectId<ContainerId::eventContext,CM> /*eventId*/) const noexcept
    {
      return !m_key.empty() && m_columnBase && m_columnBase->eventStore().contains< std::remove_cv_t<typename CI::xAODObjectRangeType> >(m_key);
    }      
 
 
 
    /// Private Members
    /// ===============
  private:
 
    ColumnarTool<CM> *m_columnBase = nullptr;
    std::string m_key;
 
    // retrieve the object from the event store.  there is probably
    // something clever that could be done with `SG::ReadHandleKey`, but
    // in practice all CP tools converted so far (25 Feb 25) do not
    // actually retrieve objects in XAOD mode.  so for simplicity and to
    // avoid some of the bookkeeping issues with "subtool" objects
    // holding accessors, I use this "non-tracking" version.
    auto& retrieveObject () const
    {
      if (m_key.empty())
        throw std::runtime_error ("no container key set for type " + std::string (CI::idName));
      typename CI::xAODObjectRangeType *container = nullptr;
      if (!m_columnBase->eventStore().retrieve (container, m_key).isSuccess())
        throw std::runtime_error ("failed to retrieve " + m_key);
      return *container;
    }
  };
}