ColumnAccessorXAOD.icc

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/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/
 
/// @author Nils Krumnack
 
 
namespace columnar
{
  // the xAOD specialization for native types
  template<ContainerIdConcept CI,typename CT,ColumnAccessMode CAM>
    requires (ColumnTypeTraits<CT,ColumnarModeXAOD>::isNativeType)
  class AccessorTemplate<CI,CT,CAM,ColumnarModeXAOD> final
  {
    /// Common Public Members
    /// =====================
  public:
 
    static_assert (!std::is_const_v<CT>, "CT must not be const");
 
    using CM = ColumnarModeXAOD;
    using ColumnType = typename ColumnAccessModeTraits<CAM>::template ColumnType<typename ColumnTypeTraits<CT,ColumnarModeXAOD>::ColumnType>;
    using AccessorType = typename ColumnAccessModeTraits<CAM>::template XAODAccessor<typename ColumnTypeTraits<CT,ColumnarModeXAOD>::ColumnType>;
 
    AccessorTemplate () = default;
 
    AccessorTemplate (ColumnarTool<CM>& columnBase,
                  const std::string& name, ColumnInfo&& info = {})
      : m_accessor(name)
    {
      if (info.addMTDependency)
        throw std::runtime_error ("adding MT dependencies not yet supported for individual decorations");
      ColumnTypeTraits<CT,ColumnarModeXAOD>::updateColumnInfo (columnBase, info);
      if (!info.replacesColumn.empty())
        m_accessor = info.replacesColumn;
    }
 
    AccessorTemplate (AccessorTemplate&& that)
      : m_accessor (that.m_accessor)
    {
      that.m_accessor = std::string("UNDEFINED_ACCESSOR_") + typeid (typename ColumnTypeTraits<CT,CM>::ColumnType).name();
    }
 
    AccessorTemplate& operator = (AccessorTemplate&& that)
    {
      if (this != &that)
      {
        m_accessor = that.m_accessor;
        that.m_accessor = std::string("UNDEFINED_ACCESSOR_") + typeid (typename ColumnTypeTraits<CT,CM>::ColumnType).name();
      }
      return *this;
    }
 
    AccessorTemplate (const AccessorTemplate&) = delete;
    AccessorTemplate& operator = (const AccessorTemplate&) = delete;
 
    [[nodiscard]] ColumnType& operator () (ObjectId<CI,CM> id) const
    {
      return m_accessor(id.getXAODObjectNoexcept());
    }
 
    [[nodiscard]] std::span<ColumnType> operator () (ObjectRange<CI,CM> range) const
    {
      if (range.getXAODObjectNoexcept().empty())
        return std::span<ColumnType> ();
      return std::span<ColumnType> (&m_accessor (*range.getXAODObjectNoexcept()[0]), range.getXAODObjectNoexcept().size());
    }
 
    [[nodiscard]] bool isAvailable (ObjectId<CI,CM> id) const noexcept
    {
      return m_accessor.isAvailable (id.getXAODObjectNoexcept());
    }
 
    [[nodiscard]] std::optional<ColumnType> getOptional (ObjectId<CI,CM> id) const
    {
      if (m_accessor.isAvailable (id.getXAODObjectNoexcept()))
        return m_accessor (id.getXAODObjectNoexcept());
      else
        return std::nullopt;
    }
 
    /// Private Members
    /// ===============
  private:
 
    AccessorType m_accessor {std::string("UNDEFINED_ACCESSOR_") + typeid (typename ColumnTypeTraits<CT,CM>::ColumnType).name()};
  };
}