IndexSourceLink.hpp

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// This file is part of the Acts project.
//
// Copyright (C) 2020 CERN for the benefit of the Acts project
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
#pragma once
 
#include "JugTrack/GeometryContainers.hpp"
#include "JugTrack/Index.hpp"
 
#include "Acts/EventData/SourceLink.hpp"
#include "Acts/Surfaces/Surface.hpp"
 
#include <cassert>
 
namespace Jug {
 
  /// A source link that stores just an index.
  ///
  /// This is intentionally kept as barebones as possible. The source link
  /// is just a reference and will be copied, moved around, etc. often.
  /// Keeping it small and separate from the actual, potentially large,
  /// measurement data should result in better overall performance.
  /// Using an index instead of e.g. a pointer, means source link and
  /// measurement are decoupled and the measurement represenation can be
  /// easily changed without having to also change the source link.
  class IndexSourceLink final : public Acts::SourceLink {
  public:
    /// Construct from geometry identifier and index.
    constexpr IndexSourceLink(Acts::GeometryIdentifier gid, Index idx) : SourceLink(gid), m_index(idx) {}
 
    // Construct an invalid source link. Must be default constructible to
    /// satisfy SourceLinkConcept.
    IndexSourceLink() : SourceLink{Acts::GeometryIdentifier{}} {}
    IndexSourceLink(const IndexSourceLink&) = default;
    IndexSourceLink(IndexSourceLink&&)      = default;
    IndexSourceLink& operator=(const IndexSourceLink&) = default;
    IndexSourceLink& operator=(IndexSourceLink&&) = default;
 
    /// Access the index.
    constexpr Index index() const { return m_index; }
 
  public:
    Index                    m_index;
 
    friend constexpr bool operator==(const IndexSourceLink& lhs, const IndexSourceLink& rhs)
    {
      return (lhs.geometryId() == rhs.geometryId()) and (lhs.m_index == rhs.m_index);
    }
    friend constexpr bool operator!=(const IndexSourceLink& lhs, const IndexSourceLink& rhs) { return not(lhs == rhs); }
  };
 
  /// Container of index source links.
  ///
  /// Since the source links provide a `.geometryId()` accessor, they can be
  /// stored in an ordered geometry container.
  using IndexSourceLinkContainer =
    GeometryIdMultiset<std::reference_wrapper<const IndexSourceLink>>;
 
  /// Accessor for the above source link container
  ///
  /// It wraps up a few lookup methods to be used in the Combinatorial Kalman
  /// Filter
  using IndexSourceLinkAccessor =
    GeometryIdMultisetAccessor<std::reference_wrapper<const IndexSourceLink>>;
 
} // namespace Jug