/****************************************************************************
*
* Copyright (c) 2014 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
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file px4_subscriber.h
*
* PX4 Subscriber API, implements subscribing to messages from a nodehandle
*/
#pragma once
#include <functional>
#include <type_traits>
#if defined(__PX4_ROS)
/* includes when building for ros */
#include "ros/ros.h"
#else
/* includes when building for NuttX */
#include <uORB/Subscription.hpp>
#include <containers/List.hpp>
#include "px4_nodehandle.h"
#endif
namespace px4
{
/**
* Untemplated subscriber base class
* */
class __EXPORT SubscriberBase
{
public:
SubscriberBase() {};
virtual ~SubscriberBase() {};
};
/**
* Subscriber class which is used by nodehandle
*/
template<typename T>
class __EXPORT Subscriber :
public SubscriberBase
{
public:
Subscriber() :
SubscriberBase(),
_msg_current()
{};
virtual ~Subscriber() {}
/* Accessors*/
/**
* Get the last message value
*/
virtual T& get() {return _msg_current;}
/**
* Get the last native message value
*/
virtual decltype(((T*)nullptr)->data()) data()
{
return _msg_current.data();
}
protected:
T _msg_current; /**< Current Message value */
};
#if defined(__PX4_ROS)
/**
* Subscriber class that is templated with the ros n message type
*/
template<typename T>
class SubscriberROS :
public Subscriber<T>
{
public:
/**
* Construct Subscriber without a callback function
*/
SubscriberROS(ros::NodeHandle *rnh) :
px4::Subscriber<T>(),
_cbf(NULL),
_ros_sub(rnh->subscribe(T::handle(), kQueueSizeDefault, &SubscriberROS<T>::callback, this))
{}
/**
* Construct Subscriber by providing a callback function
*/
SubscriberROS(ros::NodeHandle *rnh, std::function<void(const T &)> cbf) :
_cbf(cbf),
_ros_sub(rnh->subscribe(T::handle(), kQueueSizeDefault, &SubscriberROS<T>::callback, this))
{}
virtual ~SubscriberROS() {};
protected:
static const uint32_t kQueueSizeDefault = 1; /**< Size of queue for ROS */
/**
* Called on topic update, saves the current message and then calls the provided callback function
* needs to use the native type as it is called by ROS
*/
void callback(const typename std::remove_reference<decltype(((T*)nullptr)->data())>::type &msg)
{
/* Store data */
this->_msg_current.data() = msg;
/* Call callback */
if (_cbf != NULL) {
_cbf(this->get());
}
}
ros::Subscriber _ros_sub; /**< Handle to ros subscriber */
std::function<void(const T &)> _cbf; /**< Callback that the user provided on the subscription */
};
#else // Building for NuttX
/**
* Because we maintain a list of subscribers we need a node class
*/
class __EXPORT SubscriberNode :
public ListNode<SubscriberNode *>
{
public:
SubscriberNode(unsigned interval) :
ListNode(),
_interval(interval)
{}
virtual ~SubscriberNode() {}
virtual void update() = 0;
virtual int getUORBHandle() = 0;
unsigned get_interval() { return _interval; }
protected:
unsigned _interval;
};
/**
* Subscriber class that is templated with the uorb subscription message type
*/
template<typename T>
class __EXPORT SubscriberUORB :
public Subscriber<T>,
public SubscriberNode
{
public:
/**
* Construct SubscriberUORB by providing orb meta data without callback
* @param interval Minimal interval between calls to callback
*/
SubscriberUORB(unsigned interval) :
SubscriberNode(interval),
_uorb_sub(new uORB::SubscriptionBase(T::handle(), interval))
{}
virtual ~SubscriberUORB() {
delete _uorb_sub;
};
/**
* Update Subscription
* Invoked by the list traversal in NodeHandle::spinOnce
*/
virtual void update()
{
if (!_uorb_sub->updated()) {
/* Topic not updated, do not call callback */
return;
}
_uorb_sub->update(get_void_ptr());
};
/* Accessors*/
int getUORBHandle() { return _uorb_sub->getHandle(); }
protected:
uORB::SubscriptionBase * _uorb_sub; /**< Handle to the subscription */
typename std::remove_reference<decltype(((T*)nullptr)->data())>::type getUORBData()
{
return (typename std::remove_reference<decltype(((T*)nullptr)->data())>::type)*_uorb_sub;
}
/**
* Get void pointer to last message value
*/
void *get_void_ptr() { return (void *)&(this->_msg_current.data()); }
};
//XXX reduce to one class with overloaded constructor?
template<typename T>
class __EXPORT SubscriberUORBCallback :
public SubscriberUORB<T>
{
public:
/**
* Construct SubscriberUORBCallback by providing orb meta data
* @param cbf Callback, executed on receiving a new message
* @param interval Minimal interval between calls to callback
*/
SubscriberUORBCallback(unsigned interval,
std::function<void(const T &)> cbf) :
SubscriberUORB<T>(interval),
_cbf(cbf)
{}
virtual ~SubscriberUORBCallback() {};
/**
* Update Subscription
* Invoked by the list traversal in NodeHandle::spinOnce
* If new data is available the callback is called
*/
virtual void update()
{
if (!this->_uorb_sub->updated()) {
/* Topic not updated, do not call callback */
return;
}
/* get latest data */
this->_uorb_sub->update(this->get_void_ptr());
/* Check if there is a callback */
if (_cbf == nullptr) {
return;
}
/* Call callback which performs actions based on this data */
_cbf(Subscriber<T>::get());
};
protected:
std::function<void(const T &)> _cbf; /**< Callback that the user provided on the subscription */
};
#endif
}
