.. _program_listing_file_include_rclcpp_executors_executor_entities_collection.hpp:

Program Listing for File executor_entities_collection.hpp
=========================================================

|exhale_lsh| :ref:`Return to documentation for file <file_include_rclcpp_executors_executor_entities_collection.hpp>` (``include/rclcpp/executors/executor_entities_collection.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   // Copyright 2023 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__EXECUTORS__EXECUTOR_ENTITIES_COLLECTION_HPP_
   #define RCLCPP__EXECUTORS__EXECUTOR_ENTITIES_COLLECTION_HPP_
   
   #include <deque>
   #include <functional>
   #include <unordered_map>
   #include <vector>
   
   #include <rclcpp/any_executable.hpp>
   #include <rclcpp/node_interfaces/node_base.hpp>
   #include <rclcpp/callback_group.hpp>
   #include <rclcpp/executors/executor_notify_waitable.hpp>
   #include <rclcpp/visibility_control.hpp>
   #include <rclcpp/wait_result.hpp>
   #include <rclcpp/wait_set.hpp>
   
   namespace rclcpp
   {
   namespace executors
   {
   
   template<typename EntityValueType>
   struct CollectionEntry
   {
     using EntityWeakPtr = typename EntityValueType::WeakPtr;
     using EntitySharedPtr = typename EntityValueType::SharedPtr;
   
     EntityWeakPtr entity;
   
     rclcpp::CallbackGroup::WeakPtr callback_group;
   };
   
   /*
    * Iterates update_from and update_to to see which entities have been added/removed between
    * the two collections.
    *
    * For each new entry (in update_from, but not in update_to),
    *   add the entity and fire the on_added callback
    * For each removed entry (in update_to, but not in update_from),
    *   remove the entity and fire the on_removed callback.
    *
    *  \param[in] update_from The collection representing the next iteration's state
    *  \param[inout] update_to The collection representing the current iteration's state
    *  \param[in] on_added Callback fired when a new entity is detected
    *  \param[in] on_removed Callback fired when an entity is removed
    */
   template<typename CollectionType>
   void update_entities(
     const CollectionType & update_from,
     CollectionType & update_to,
     std::function<void(const typename CollectionType::EntitySharedPtr &)> on_added,
     std::function<void(const typename CollectionType::EntitySharedPtr &)> on_removed
   )
   {
     for (auto it = update_to.begin(); it != update_to.end(); ) {
       if (update_from.count(it->first) == 0) {
         auto entity = it->second.entity.lock();
         if (entity) {
           on_removed(entity);
         }
         it = update_to.erase(it);
       } else {
         ++it;
       }
     }
     for (auto it = update_from.begin(); it != update_from.end(); ++it) {
       if (update_to.count(it->first) == 0) {
         auto entity = it->second.entity.lock();
         if (entity) {
           on_added(entity);
         }
         update_to.insert(*it);
       }
     }
   }
   
   template<typename EntityKeyType, typename EntityValueType>
   class EntityCollection
     : public std::unordered_map<const EntityKeyType *, CollectionEntry<EntityValueType>>
   {
   public:
     using Key = const EntityKeyType *;
   
     using EntityWeakPtr = typename EntityValueType::WeakPtr;
   
     using EntitySharedPtr = typename EntityValueType::SharedPtr;
   
   
     void update(
       const EntityCollection<EntityKeyType, EntityValueType> & other,
       std::function<void(const EntitySharedPtr &)> on_added,
       std::function<void(const EntitySharedPtr &)> on_removed)
     {
       update_entities(other, *this, on_added, on_removed);
     }
   };
   
   
   struct ExecutorEntitiesCollection
   {
     using TimerCollection = EntityCollection<rcl_timer_t, rclcpp::TimerBase>;
   
     using SubscriptionCollection = EntityCollection<rcl_subscription_t, rclcpp::SubscriptionBase>;
   
     using ClientCollection = EntityCollection<rcl_client_t, rclcpp::ClientBase>;
   
     using ServiceCollection = EntityCollection<rcl_service_t, rclcpp::ServiceBase>;
   
     using WaitableCollection = EntityCollection<rclcpp::Waitable, rclcpp::Waitable>;
   
     using GuardConditionCollection = EntityCollection<rcl_guard_condition_t, rclcpp::GuardCondition>;
   
     TimerCollection timers;
   
     SubscriptionCollection subscriptions;
   
     ClientCollection clients;
   
     ServiceCollection services;
   
     GuardConditionCollection guard_conditions;
   
     WaitableCollection waitables;
   
   
     bool empty() const;
   
     void clear();
   
   
     size_t remove_expired_entities();
   };
   
   
   void
   build_entities_collection(
     const std::vector<rclcpp::CallbackGroup::WeakPtr> & callback_groups,
     ExecutorEntitiesCollection & collection);
   
   
   size_t
   ready_executables(
     const ExecutorEntitiesCollection & collection,
     rclcpp::WaitResult<rclcpp::WaitSet> & wait_result,
     std::deque<rclcpp::AnyExecutable> & executables
   );
   }  // namespace executors
   }  // namespace rclcpp
   
   #endif  // RCLCPP__EXECUTORS__EXECUTOR_ENTITIES_COLLECTION_HPP_