px4_autopilot/apps/controllib/block/UOrbSubscription.hpp

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/**
 * @file UOrbSubscription.h
 *
 */

#pragma once

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


namespace control
{

class Block;

/**
 * Base subscription warapper class, used in list traversal
 * of various subscriptions.
 */
class __EXPORT UOrbSubscriptionBase :
	public ListNode<control::UOrbSubscriptionBase *>
{
public:
// methods

	/**
	 * Constructor
	 *
	 * @param meta		The uORB metadata (usually from the ORB_ID() macro)
	 *			for the topic.
	 */
	UOrbSubscriptionBase(
		List<UOrbSubscriptionBase *> * list,
		const struct orb_metadata *meta) :
		_meta(meta),
		_handle() {
		if (list != NULL) list->add(this);
	}
	bool updated();
	void update() {
		if (updated()) {
			orb_copy(_meta, _handle, getDataVoidPtr());
		}
	}
	virtual void *getDataVoidPtr() = 0;
	virtual ~UOrbSubscriptionBase() {
		orb_unsubscribe(_handle);
	}
// accessors
	const struct orb_metadata *getMeta() { return _meta; }
	int getHandle() { return _handle; }
protected:
// accessors
	void setHandle(int handle) { _handle = handle; }
// attributes
	const struct orb_metadata *_meta;
	int _handle;
};

/**
 * UOrb Subscription wrapper class
 */
template<class T>
class __EXPORT UOrbSubscription :
	public T, // this must be first!
	public UOrbSubscriptionBase
{
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.
	 * @param interval  The minimum interval in milliseconds between updates
	 */
	UOrbSubscription(
		List<UOrbSubscriptionBase *> * list,
		const struct orb_metadata *meta, unsigned interval) :
		T(), // initialize data structure to zero
		UOrbSubscriptionBase(list, meta) {
		setHandle(orb_subscribe(getMeta()));
		orb_set_interval(getHandle(), interval);
	}

	/**
	 * Deconstructor
	 */
	virtual ~UOrbSubscription() {}

	/*
	 * 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); }
	T getData() { return T(*this); }
};

} // namespace control