Program Listing for File is_manageable_node.hpp

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// Copyright 2016 Open Source Robotics Foundation, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef RCLCPP_LIFECYCLE__TYPE_TRAITS__IS_MANAGEABLE_NODE_HPP_
#define RCLCPP_LIFECYCLE__TYPE_TRAITS__IS_MANAGEABLE_NODE_HPP_

#include <utility>
#include <type_traits>

template<class T, typename = void>
struct has_on_activate
{
  static constexpr bool value = false;
};

template<class T>
struct has_on_activate<
  T,
  typename std::enable_if<
    std::is_same<void, decltype(std::declval<T>().on_activate())>::value>::type>
{
  static constexpr bool value = true;
};

template<class T, typename = void>
struct has_on_deactivate
{
  static constexpr bool value = false;
};

template<class T>
struct has_on_deactivate<
  T,
  typename std::enable_if<
    std::is_same<void, decltype(std::declval<T>().on_deactivate())>::value>::type>
{
  static constexpr bool value = true;
};

template<class T, typename = void>
struct is_manageable_node : std::false_type
{};

template<class T>
struct is_manageable_node<
  T,
  typename std::enable_if<
    has_on_activate<T>::value && has_on_deactivate<T>::value>::type>: std::true_type
{};

#endif  // RCLCPP_LIFECYCLE__TYPE_TRAITS__IS_MANAGEABLE_NODE_HPP_