Subscription.hpp

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#pragma once

#include <uORB/uORB.h>
#include <containers/List.hpp>
#include <systemlib/err.h>
#include <px4_defines.h>

namespace uORB
{

class __EXPORT SubscriptionBase
{
public:
    SubscriptionBase(const struct orb_metadata *meta, unsigned interval = 0, unsigned instance = 0);
    virtual ~SubscriptionBase();

    // no copy, assignment, move, move assignment
    SubscriptionBase(const SubscriptionBase &) = delete;
    SubscriptionBase &operator=(const SubscriptionBase &) = delete;
    SubscriptionBase(SubscriptionBase &&) = delete;
    SubscriptionBase &operator=(SubscriptionBase &&) = delete;

    bool updated();

    bool update(void *data);

    int getHandle() const { return _handle; }

    const orb_metadata *getMeta() const { return _meta; }

    unsigned getInstance() const { return _instance; }

protected:
    const struct orb_metadata *_meta;

    unsigned _instance;

    int _handle{-1};
};

typedef SubscriptionBase SubscriptionTiny;

class __EXPORT SubscriptionNode : public SubscriptionBase, public ListNode<SubscriptionNode *>
{
public:
    SubscriptionNode(const struct orb_metadata *meta, unsigned interval = 0, unsigned instance = 0,
             List<SubscriptionNode *> *list = nullptr);

    virtual ~SubscriptionNode() override = default;

    virtual bool update() = 0;

    virtual bool forcedUpdate() = 0;

};

template<class T>
class __EXPORT Subscription : public SubscriptionNode
{
public:
    Subscription(const struct orb_metadata *meta, unsigned interval = 0, unsigned instance = 0,
             List<SubscriptionNode *> *list = nullptr):
        SubscriptionNode(meta, interval, instance, list),
        _data() // initialize data structure to zero
    {
        forcedUpdate();
    }

    ~Subscription() override = default;

    // no copy, assignment, move, move assignment
    Subscription(const Subscription &) = delete;
    Subscription &operator=(const Subscription &) = delete;
    Subscription(Subscription &&) = delete;
    Subscription &operator=(Subscription &&) = delete;

    bool update() override
    {
        return SubscriptionBase::update((void *)(&_data));
    }

    bool forcedUpdate() override
    {
        return orb_copy(_meta, _handle, &_data) == PX4_OK;
    }

    /*
     * This function gets the T struct data
     * */
    const T &get() const
    {
        return _data;
    }

private:
    T _data;
};

} // namespace uORB