px4-firmware/platforms/common/uORB/uORBDeviceMaster.hpp

/****************************************************************************
 *
 *   Copyright (c) 2012-2016 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.
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 *    distribution.
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 *    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
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#pragma once

#include <stdint.h>

#include "uORBCommon.hpp"
#include <uORB/topics/uORBTopics.hpp>

#include <px4_platform_common/posix.h>

namespace uORB
{
class DeviceNode;
class DeviceMaster;
class Manager;
}

#include <string.h>
#include <stdlib.h>

#include <containers/IntrusiveSortedList.hpp>
#include <px4_platform_common/atomic_bitset.h>

using px4::AtomicBitset;

/**
 * Master control device for ObjDev.
 *
 * Used primarily to create new objects via the ORBIOCCREATE
 * ioctl.
 */
class uORB::DeviceMaster
{
public:

	int advertise(const struct orb_metadata *meta, bool is_advertiser, int *instance);

	/**
	 * Public interface for getDeviceNodeLocked(). Takes care of synchronization.
	 * @return node if exists, nullptr otherwise
	 */
	uORB::DeviceNode *getDeviceNode(const char *node_name);
	uORB::DeviceNode *getDeviceNode(const struct orb_metadata *meta, const uint8_t instance)
	{
		if (meta == nullptr) {
			return nullptr;
		}

		if (!deviceNodeExists(static_cast<ORB_ID>(meta->o_id), instance)) {
			return nullptr;
		}

		lock();
		uORB::DeviceNode *node = getDeviceNodeLocked(meta, instance);
		unlock();

		//We can safely return the node that can be used by any thread, because
		//a DeviceNode never gets deleted.
		return node;

	}

	bool deviceNodeExists(ORB_ID id, const uint8_t instance)
	{
		if ((id == ORB_ID::INVALID) || (instance > ORB_MULTI_MAX_INSTANCES - 1)) {
			return false;
		}

		return _node_exists[instance][(orb_id_size_t)id];
	}

	/**
	 * Print statistics for each existing topic.
	 */
	void printStatistics();

	/**
	 * Continuously print statistics, like the unix top command for processes.
	 * Exited when the user presses the enter key.
	 * @param topic_filter list of topic filters: if set, each string can be a substring for topics to match.
	 *        Or it can be '-a', which means to print all topics instead of only ones currently publishing with subscribers.
	 * @param num_filters
	 */
	void showTop(char **topic_filter, int num_filters);

private:
	// Private constructor, uORB::Manager takes care of its creation
	DeviceMaster();
	~DeviceMaster();

	struct DeviceNodeStatisticsData {
		DeviceNode *node;
		unsigned int last_pub_msg_count;
		unsigned int pub_msg_delta;
		DeviceNodeStatisticsData *next = nullptr;
	};

	int addNewDeviceNodes(DeviceNodeStatisticsData **first_node, int &num_topics, size_t &max_topic_name_length,
			      char **topic_filter, int num_filters);

	friend class uORB::Manager;

	/**
	 * Find a node give its name.
	 * _lock must already be held when calling this.
	 * @return node if exists, nullptr otherwise
	 */
	uORB::DeviceNode *getDeviceNodeLocked(const struct orb_metadata *meta, const uint8_t instance);

	IntrusiveSortedList<uORB::DeviceNode *> _node_list;
	AtomicBitset<ORB_TOPICS_COUNT> _node_exists[ORB_MULTI_MAX_INSTANCES];

	px4_sem_t	_lock; /**< lock to protect access to all class members (also for derived classes) */

	void		lock() { do {} while (px4_sem_wait(&_lock) != 0); }
	void		unlock() { px4_sem_post(&_lock); }
};