.. _program_listing_file__tmp_ws_src_twist_mux_include_twist_mux_topic_handle.hpp:

Program Listing for File topic_handle.hpp
=========================================

|exhale_lsh| :ref:`Return to documentation for file <file__tmp_ws_src_twist_mux_include_twist_mux_topic_handle.hpp>` (``/tmp/ws/src/twist_mux/include/twist_mux/topic_handle.hpp``)

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

.. code-block:: cpp

   // Copyright 2020 PAL Robotics S.L.
   //
   // Redistribution and use in source and binary forms, with or without
   // modification, are permitted provided that the following conditions are met:
   //
   //    * Redistributions of source code must retain the above copyright
   //      notice, this list of conditions and the following disclaimer.
   //
   //    * Redistributions in binary form must reproduce the above copyright
   //      notice, this list of conditions and the following disclaimer in the
   //      documentation and/or other materials provided with the distribution.
   //
   //    * Neither the name of the PAL Robotics S.L. nor the names of its
   //      contributors may be used to endorse or promote products derived from
   //      this software without specific prior written permission.
   //
   // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
   // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   // POSSIBILITY OF SUCH DAMAGE.
   
   /*
    * @author Enrique Fernandez
    * @author Siegfried Gevatter
    * @author Jeremie Deray
    * @author Brighten Lee
    */
   
   #ifndef TWIST_MUX__TOPIC_HANDLE_HPP_
   #define TWIST_MUX__TOPIC_HANDLE_HPP_
   
   #include <rclcpp/rclcpp.hpp>
   #include <std_msgs/msg/bool.hpp>
   #include <geometry_msgs/msg/twist.hpp>
   
   #include <twist_mux/utils.hpp>
   #include <twist_mux/twist_mux.hpp>
   
   #include <memory>
   #include <string>
   #include <vector>
   
   namespace twist_mux
   {
   template<typename T>
   class TopicHandle_
   {
   public:
     // Not copy constructible
     TopicHandle_(TopicHandle_ &) = delete;
     TopicHandle_(const TopicHandle_ &) = delete;
   
     // Not copy assignable
     TopicHandle_ & operator=(TopicHandle_ &) = delete;
     TopicHandle_ & operator=(const TopicHandle_ &) = delete;
   
     typedef int priority_type;
   
     TopicHandle_(
       const std::string & name, const std::string & topic, const rclcpp::Duration & timeout,
       priority_type priority, TwistMux * mux)
     : name_(name),
       topic_(topic),
       timeout_(timeout),
       priority_(clamp(priority, priority_type(0), priority_type(255))),
       mux_(mux),
       stamp_(0)
     {
       RCLCPP_INFO(
         mux_->get_logger(),
         "Topic handler '%s' subscribed to topic '%s': timeout = %s , priority = %d.",
         name_.c_str(), topic_.c_str(),
         ((timeout_.seconds() > 0) ? std::to_string(timeout_.seconds()) + "s" : "None").c_str(),
         static_cast<int>(priority_));
     }
   
     virtual ~TopicHandle_() = default;
   
     bool hasExpired() const
     {
       return (timeout_.seconds() > 0.0) && (
         (mux_->now().seconds() - stamp_.seconds()) > timeout_.seconds());
     }
   
     const std::string & getName() const
     {
       return name_;
     }
   
     const std::string & getTopic() const
     {
       return topic_;
     }
   
     const rclcpp::Duration & getTimeout() const
     {
       return timeout_;
     }
   
     const priority_type & getPriority() const
     {
       return priority_;
     }
   
     const T & getStamp() const
     {
       return stamp_;
     }
   
     const T & getMessage() const
     {
       return msg_;
     }
   
   protected:
     std::string name_;
     std::string topic_;
     typename rclcpp::Subscription<T>::SharedPtr subscriber_;
     rclcpp::Duration timeout_;
     priority_type priority_;
   
   protected:
     TwistMux * mux_;
   
     rclcpp::Time stamp_;
     T msg_;
   };
   
   class VelocityTopicHandle : public TopicHandle_<geometry_msgs::msg::Twist>
   {
   private:
     typedef TopicHandle_<geometry_msgs::msg::Twist> base_type;
   
     // https://index.ros.org/doc/ros2/About-Quality-of-Service-Settings
     // rmw_qos_profile_t twist_qos_profile = rmw_qos_profile_sensor_data;
   
   public:
     typedef typename base_type::priority_type priority_type;
   
     VelocityTopicHandle(
       const std::string & name, const std::string & topic, const rclcpp::Duration & timeout,
       priority_type priority, TwistMux * mux)
     : base_type(name, topic, timeout, priority, mux)
     {
       subscriber_ = mux_->create_subscription<geometry_msgs::msg::Twist>(
         topic_, rclcpp::SystemDefaultsQoS(),
         std::bind(&VelocityTopicHandle::callback, this, std::placeholders::_1));
   
       // subscriber_ = nh_.create_subscription<geometry_msgs::msg::Twist>(
       //    topic_, twist_qos_profile,
       //  std::bind(&VelocityTopicHandle::callback, this, std::placeholders::_1));
     }
   
     bool isMasked(priority_type lock_priority) const
     {
       // std::cout << hasExpired() << " / " << (getPriority() < lock_priority) << std::endl;
       return hasExpired() || (getPriority() < lock_priority);
     }
   
     void callback(const geometry_msgs::msg::Twist::ConstSharedPtr msg)
     {
       stamp_ = mux_->now();
       msg_ = *msg;
   
       // Check if this twist has priority.
       // Note that we have to check all the locks because they might time out
       // and since we have several topics we must look for the highest one in
       // all the topic list; so far there's no O(1) solution.
       if (mux_->hasPriority(*this)) {
         mux_->publishTwist(msg);
       }
     }
   };
   
   class LockTopicHandle : public TopicHandle_<std_msgs::msg::Bool>
   {
   private:
     typedef TopicHandle_<std_msgs::msg::Bool> base_type;
   
     // https://index.ros.org/doc/ros2/About-Quality-of-Service-Settings
     // rmw_qos_profile_t lock_qos_profile = rmw_qos_profile_sensor_data;
   
   public:
     typedef typename base_type::priority_type priority_type;
   
     LockTopicHandle(
       const std::string & name, const std::string & topic, const rclcpp::Duration & timeout,
       priority_type priority, TwistMux * mux)
     : base_type(name, topic, timeout, priority, mux)
     {
       subscriber_ = mux_->create_subscription<std_msgs::msg::Bool>(
         topic_, rclcpp::SystemDefaultsQoS(),
         std::bind(&LockTopicHandle::callback, this, std::placeholders::_1));
     }
   
     bool isLocked() const
     {
       return hasExpired() || getMessage().data;
     }
   
     void callback(const std_msgs::msg::Bool::ConstSharedPtr msg)
     {
       stamp_ = mux_->now();
       msg_ = *msg;
     }
   };
   
   }  // namespace twist_mux
   
   #endif  // TWIST_MUX__TOPIC_HANDLE_HPP_