PX4-Autopilot/src/modules/uORB/SubscriptionCallback.hpp
2019-09-28 13:43:56 -04:00

138 lines
4.1 KiB
C++

/****************************************************************************
*
* Copyright (c) 2019 PX4 Development Team. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name PX4 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
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****************************************************************************/
/**
* @file SubscriptionCallback.hpp
*
*/
#pragma once
#include <uORB/SubscriptionInterval.hpp>
#include <containers/List.hpp>
#include <px4_platform_common/px4_work_queue/WorkItem.hpp>
namespace uORB
{
// Subscription wrapper class with callbacks on new publications
class SubscriptionCallback : public SubscriptionInterval, public ListNode<SubscriptionCallback *>
{
public:
/**
* Constructor
*
* @param meta The uORB metadata (usually from the ORB_ID() macro) for the topic.
* @param interval_ms The requested maximum update interval in milliseconds.
* @param instance The instance for multi sub.
*/
SubscriptionCallback(const orb_metadata *meta, uint8_t interval_ms = 0, uint8_t instance = 0) :
SubscriptionInterval(meta, interval_ms, instance)
{
}
virtual ~SubscriptionCallback()
{
unregisterCallback();
};
bool registerCallback()
{
bool ret = false;
if (_subscription.get_node() && _subscription.get_node()->register_callback(this)) {
// registered
ret = true;
} else {
// force topic creation by subscribing with old API
int fd = orb_subscribe_multi(_subscription.get_topic(), _subscription.get_instance());
// try to register callback again
if (_subscription.subscribe()) {
if (_subscription.get_node() && _subscription.get_node()->register_callback(this)) {
ret = true;
}
}
orb_unsubscribe(fd);
}
return ret;
}
void unregisterCallback()
{
if (_subscription.get_node()) {
_subscription.get_node()->unregister_callback(this);
}
}
virtual void call() = 0;
};
// Subscription with callback that schedules a WorkItem
class SubscriptionCallbackWorkItem : public SubscriptionCallback
{
public:
/**
* Constructor
*
* @param work_item The WorkItem that will be scheduled immediately on new publications.
* @param meta The uORB metadata (usually from the ORB_ID() macro) for the topic.
* @param instance The instance for multi sub.
*/
SubscriptionCallbackWorkItem(px4::WorkItem *work_item, const orb_metadata *meta, uint8_t instance = 0) :
SubscriptionCallback(meta, 0, instance), // interval 0
_work_item(work_item)
{
}
virtual ~SubscriptionCallbackWorkItem() = default;
void call() override
{
// schedule immediately if no interval, otherwise check time elapsed
if ((_interval_us == 0) || (hrt_elapsed_time_atomic(&_last_update) >= _interval_us)) {
_work_item->ScheduleNow();
}
}
private:
px4::WorkItem *_work_item;
};
} // namespace uORB