visitors.hpp

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/*
 * Copyright (C) 2022 The ESPResSo project
 *
 * This file is part of ESPResSo.
 *
 * ESPResSo is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * ESPResSo is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef ESPRESSO_SRC_CORE_ACTOR_VISITORS_HPP
#define ESPRESSO_SRC_CORE_ACTOR_VISITORS_HPP
 
#include "actor/traits.hpp"
 
#include <functional>
#include <memory>
#include <optional>
#include <string>
#include <type_traits>
#include <variant>
 
/** @brief Get an actor of a specific type, recursively. */
template <typename Actor> struct GetActorByType {
private:
  template <typename T>
  static constexpr bool is_exact_match_v = std::is_same_v<T, Actor>;
  template <typename T>
  static constexpr bool is_layer_correction_v =
      traits::is_layer_correction<T>::value;
 
public:
  template <typename T, std::enable_if_t<is_exact_match_v<T>> * = nullptr>
  auto operator()(std::shared_ptr<T> const &obj) const {
    return obj;
  }
 
  template <typename T, std::enable_if_t<not is_exact_match_v<T> and
                                         is_layer_correction_v<T>> * = nullptr>
  auto operator()(std::shared_ptr<T> const &obj) const {
    return std::visit(*this, obj->base_solver);
  }
 
  template <typename T,
            std::enable_if_t<not is_exact_match_v<T> and
                             not is_layer_correction_v<T>> * = nullptr>
  auto operator()(std::shared_ptr<T> const &) const {
    return std::shared_ptr<Actor>{nullptr};
  }
};
 
/** @brief Get an active actor of a specific type, recursively. */
template <typename Actor, typename Variant>
std::shared_ptr<Actor> get_actor_by_type(Variant const &variant) {
  return std::visit(GetActorByType<Actor>(), variant);
}
 
template <typename Actor, typename Variant>
std::shared_ptr<Actor>
get_actor_by_type(std::optional<Variant> const &optional) {
  return (optional) ? get_actor_by_type<Actor>(*optional) : nullptr;
}
 
/** @brief Check if an actor of a specific type is active, recursively. */
template <typename Actor> struct HasActorOfType {
private:
  template <typename T>
  static constexpr bool is_exact_match_v = std::is_same_v<T, Actor>;
  template <typename T>
  static constexpr bool is_layer_correction_v =
      traits::is_layer_correction<T>::value;
 
public:
  template <typename T, std::enable_if_t<is_exact_match_v<T>> * = nullptr>
  auto operator()(std::shared_ptr<T> const &) const {
    return true;
  }
 
  template <typename T, std::enable_if_t<not is_exact_match_v<T> and
                                         is_layer_correction_v<T>> * = nullptr>
  auto operator()(std::shared_ptr<T> const &obj) const {
    return std::visit(*this, obj->base_solver);
  }
 
  template <typename T,
            std::enable_if_t<not is_exact_match_v<T> and
                             not is_layer_correction_v<T>> * = nullptr>
  auto operator()(std::shared_ptr<T> const &) const {
    return false;
  }
};
 
/** @brief Check if an actor of a specific type is active, recursively. */
template <typename Actor, typename Variant>
auto has_actor_of_type(Variant const &variant) {
  return std::visit(HasActorOfType<Actor>(), variant);
}
 
template <typename Actor, typename Variant>
auto has_actor_of_type(std::optional<Variant> const &optional) {
  return (optional) ? has_actor_of_type<Actor>(*optional) : false;
}
 
#endif