px4_autopilot/apps/controllib/block/UOrbPublication.hpp

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/**
 * @file UOrbPublication.h
 *
 */

#pragma once

#include <uORB/uORB.h>
#include "Block.hpp"
#include "List.hpp"


namespace control
{

class Block;

/**
 * Base publication warapper class, used in list traversal
 * of various publications.
 */
class __EXPORT UOrbPublicationBase : public ListNode<control::UOrbPublicationBase *>
{
public:

	UOrbPublicationBase(
		List<UOrbPublicationBase *> * list,
		const struct orb_metadata *meta) :
		_meta(meta),
		_handle() {
		if (list != NULL) list->add(this);
	}
	void update() {
		orb_publish(getMeta(), getHandle(), getDataVoidPtr());
	}
	virtual void *getDataVoidPtr() = 0;
	virtual ~UOrbPublicationBase() {
		orb_unsubscribe(getHandle());
	}
	const struct orb_metadata *getMeta() { return _meta; }
	int getHandle() { return _handle; }
protected:
	void setHandle(orb_advert_t handle) { _handle = handle; }
	const struct orb_metadata *_meta;
	orb_advert_t _handle;
};

/**
 * UOrb Publication wrapper class
 */
template<class T>
class UOrbPublication :
	public T, // this must be first!
	public UOrbPublicationBase
{
public:
	/**
	 * Constructor
	 *
	 * @param list      A list interface for adding to list during construction
	 * @param meta		The uORB metadata (usually from the ORB_ID() macro)
	 *			for the topic.
	 */
	UOrbPublication(
		List<UOrbPublicationBase *> * list,
		const struct orb_metadata *meta) :
		T(), // initialize data structure to zero
		UOrbPublicationBase(list, meta) {
		// It is important that we call T()
		// before we publish the data, so we
		// call this here instead of the base class
		setHandle(orb_advertise(getMeta(), getDataVoidPtr()));
	}
	virtual ~UOrbPublication() {}
	/*
	 * XXX
	 * This function gets the T struct, assuming
	 * the struct is the first base class, this
	 * should use dynamic cast, but doesn't
	 * seem to be available
	 */
	void *getDataVoidPtr() { return (void *)(T *)(this); }
};

} // namespace control