.. _program_listing_file_include_rclcpp_experimental_executors_events_executor_simple_events_queue.hpp:

Program Listing for File simple_events_queue.hpp
================================================

|exhale_lsh| :ref:`Return to documentation for file <file_include_rclcpp_experimental_executors_events_executor_simple_events_queue.hpp>` (``include/rclcpp/experimental/executors/events_executor/simple_events_queue.hpp``)

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

.. code-block:: cpp

   // Copyright 2023 iRobot Corporation.
   //
   // 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__EXPERIMENTAL__EXECUTORS__EVENTS_EXECUTOR__SIMPLE_EVENTS_QUEUE_HPP_
   #define RCLCPP__EXPERIMENTAL__EXECUTORS__EVENTS_EXECUTOR__SIMPLE_EVENTS_QUEUE_HPP_
   
   #include <condition_variable>
   #include <mutex>
   #include <queue>
   #include <utility>
   
   #include "rclcpp/experimental/executors/events_executor/events_queue.hpp"
   
   namespace rclcpp
   {
   namespace experimental
   {
   namespace executors
   {
   
   class SimpleEventsQueue : public EventsQueue
   {
   public:
     RCLCPP_PUBLIC
     ~SimpleEventsQueue() override = default;
   
     RCLCPP_PUBLIC
     void
     enqueue(const rclcpp::experimental::executors::ExecutorEvent & event) override
     {
       rclcpp::experimental::executors::ExecutorEvent single_event = event;
       single_event.num_events = 1;
       {
         std::unique_lock<std::mutex> lock(mutex_);
         for (size_t ev = 0; ev < event.num_events; ev++) {
           event_queue_.push(single_event);
         }
       }
       events_queue_cv_.notify_one();
     }
   
     RCLCPP_PUBLIC
     bool
     dequeue(
       rclcpp::experimental::executors::ExecutorEvent & event,
       std::chrono::nanoseconds timeout = std::chrono::nanoseconds::max()) override
     {
       std::unique_lock<std::mutex> lock(mutex_);
   
       // Initialize to true because it's only needed if we have a valid timeout
       bool has_data = true;
       if (timeout != std::chrono::nanoseconds::max()) {
         has_data =
           events_queue_cv_.wait_for(lock, timeout, [this]() {return !event_queue_.empty();});
       } else {
         events_queue_cv_.wait(lock, [this]() {return !event_queue_.empty();});
       }
   
       if (has_data) {
         event = event_queue_.front();
         event_queue_.pop();
         return true;
       }
   
       return false;
     }
   
     RCLCPP_PUBLIC
     bool
     empty() const override
     {
       std::unique_lock<std::mutex> lock(mutex_);
       return event_queue_.empty();
     }
   
     RCLCPP_PUBLIC
     size_t
     size() const override
     {
       std::unique_lock<std::mutex> lock(mutex_);
       return event_queue_.size();
     }
   
   private:
     // The underlying queue implementation
     std::queue<rclcpp::experimental::executors::ExecutorEvent> event_queue_;
     // Mutex to protect read/write access to the queue
     mutable std::mutex mutex_;
     // Variable used to notify when an event is added to the queue
     std::condition_variable events_queue_cv_;
   };
   
   }  // namespace executors
   }  // namespace experimental
   }  // namespace rclcpp
   
   #endif  // RCLCPP__EXPERIMENTAL__EXECUTORS__EVENTS_EXECUTOR__SIMPLE_EVENTS_QUEUE_HPP_