text: /*
   * Copyright (c) 2019, Open Source Robotics Foundation, Inc.
   * All rights reserved.
   *
   * 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 Willow Garage, Inc. 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 OWNER 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.
   */
  
  #ifndef TF2_ROS__CREATE_TIMER_ROS_H_
  #define TF2_ROS__CREATE_TIMER_ROS_H_
  
  #include <tf2_ros/create_timer_interface.h>
  #include <tf2_ros/visibility_control.h>
  #include <tf2/time.h>
  
  #include <rclcpp/rclcpp.hpp>
  
  #include <mutex>
  #include <unordered_map>
  
  namespace tf2_ros
  {
  
  /**
   * \brief Create and manage ROS timers.
   *
   * This class is thread safe.
   */
  class CreateTimerROS : public CreateTimerInterface
  {
  public:
    TF2_ROS_PUBLIC
    CreateTimerROS(
      rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base,
      rclcpp::node_interfaces::NodeTimersInterface::SharedPtr node_timers);
  
    virtual ~CreateTimerROS() = default;
  
    /**
     * \brief Create a new timer.
     *
     * After creation, the timer will periodically execute the user-provided callback.
     *
     * \param clock The clock providing the current time
     * \param period The interval at which the timer fires
     * \param callback The callback function to execute every interval
     */
    TF2_ROS_PUBLIC
    TimerHandle
    createTimer(
      rclcpp::Clock::SharedPtr clock,
      const tf2::Duration & period,
      TimerCallbackType callback) override;
  
    /**
     * \brief Cancel a timer.
     *
     * The timer will stop executing user callbacks.
     *
     * \param timer_handle Handle to the timer to cancel
     * \raises tf2_ros::InvalidTimerHandleException if the timer does not exist
     */
    TF2_ROS_PUBLIC
    void
    cancel(const TimerHandle & timer_handle) override;
  
    /**
     * \brief Reset the timer.
     *
     * The timer will reset and continue to execute user callbacks periodically.
     *
     * \param timer_handle Handle to the timer to reset
     * \raises tf2_ros::InvalidTimerHandleException if the timer does not exist
     */
    TF2_ROS_PUBLIC
    void
    reset(const TimerHandle & timer_handle) override;
  
    /**
     * \brief Remove a timer.
     *
     * The timer will be canceled and removed from internal storage.
     *
     * \param timer_handle Handle to the timer to reset.
     * \raises tf2_ros::InvalidTimerHandleException if the timer does not exist
     */
    TF2_ROS_PUBLIC
    void
    remove(const TimerHandle & timer_handle) override;
  
  private:
    void
    cancelNoLock(const TimerHandle & timer_handle);
  
    void
    timerCallback(
      const TimerHandle & timer_handle,
      TimerCallbackType callback);
  
    rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base_;
    rclcpp::node_interfaces::NodeTimersInterface::SharedPtr node_timers_;
    TimerHandle next_timer_handle_index_;
    std::unordered_map<TimerHandle, rclcpp::TimerBase::SharedPtr> timers_map_;
    std::mutex timers_map_mutex_;
  };  // class CreateTimerROS
  
  }  // namespace tf2_ros
  
  #endif  // TF2_ROS__CREATE_TIMER_ROS_H_
  