PX4-Autopilot/platforms/ros2/include/uORB/Publication.hpp

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/**
 * @file Publication.hpp
 *
 */

#pragma once

#include "rclcpp/rclcpp.hpp"

#include "uORB.h"

namespace uORB
{

template <typename U> class DefaultQueueSize
{
private:
	template <typename T>
	static constexpr uint8_t get_queue_size(decltype(T::ORB_QUEUE_LENGTH) *)
	{
		return T::ORB_QUEUE_LENGTH;
	}

	template <typename T> static constexpr uint8_t get_queue_size(...)
	{
		return 1;
	}

public:
	static constexpr unsigned value = get_queue_size<U>(nullptr);
};

/**
 * uORB publication wrapper class
 */
template<typename T, uint8_t ORB_QSIZE = DefaultQueueSize<T>::value>
class Publication
{
public:

	/**
	 * Constructor
	 *
	 * @param meta The uORB metadata (usually from the ORB_ID() macro) for the topic.
	 */
	Publication(rclcpp::Node *node, ORB_ID id) : _node(*node), _id(id)
	{
		_publisher = _node.create_publisher<T>(::get_topic_string(_id), ORB_QSIZE); // TODO
	}

	bool advertised() { return (_publisher != nullptr); }

	bool advertise()
	{
		if (!advertised()) {
			_publisher = _node.create_publisher<T>(get_topic_string(_id), ORB_QSIZE);
		}

		return advertised();
	}

	/**
	 * Publish the struct
	 * @param data The uORB message struct we are updating.
	 */
	bool publish(const T &data)
	{
		if (!advertised()) {
			advertise();
		}

		_publisher->publish(data);

		return true;
	}

private:
	typename rclcpp::Publisher<T>::SharedPtr _publisher{nullptr};

	rclcpp::Node &_node;

	const ORB_ID _id;
};

/**
 * The publication class with data embedded.
 */
template<typename T>
class PublicationData : public Publication<T>
{
public:
	/**
	 * Constructor
	 *
	 * @param meta The uORB metadata (usually from the ORB_ID() macro) for the topic.
	 */
	PublicationData(ORB_ID id) : Publication<T>(id) {}
	//PublicationData(const orb_metadata *meta) : Publication<T>(meta) {}

	T	&get() { return _data; }
	void	set(const T &data) { _data = data; }

	// Publishes the embedded struct.
	bool	update() { return Publication<T>::publish(_data); }
	bool	update(const T &data)
	{
		_data = data;
		return Publication<T>::publish(_data);
	}

private:
	T _data{};
};

} // namespace uORB