orb_exists support for muorb

Also added builtin command wait_for_topic

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/modules/uORB/uORBCommunicator.hpp

@@ -56,6 +56,33 @@ public:
 	//     INTERFACES FOR Control messages over a channel.
 	//=========================================================================
 
+	/**
+	 * @brief Interface to notify the remote entity of a topic being advertised.
+	 *
+	 * @param messageName
+	 * 	This represents the uORB message name(aka topic); This message name should be
+	 * 	globally unique.
+	 * @return
+	 * 	0 = success; This means the messages is successfully sent to the receiver
+	 * 		Note: This does not mean that the receiver as received it.
+	 *  otherwise = failure.
+	 */
+	virtual int16_t topic_advertised(const char *messageName) = 0;
+
+	/**
+	 * @brief Interface to notify the remote entity of a topic being unadvertised
+	 * and is no longer publishing messages.
+	 *
+	 * @param messageName
+	 * 	This represents the uORB message name(aka topic); This message name should be
+	 * 	globally unique.
+	 * @return
+	 * 	0 = success; This means the messages is successfully sent to the receiver
+	 * 		Note: This does not mean that the receiver as received it.
+	 *  otherwise = failure.
+	 */
+	//virtual int16_t topic_unadvertised(const char *messageName) = 0;
+
 	/**
 	 * @brief Interface to notify the remote entity of interest of a
 	 * subscription for a message.
@@ -127,6 +154,21 @@ class uORBCommunicator::IChannelRxHandler
 {
 public:
 
+	/**
+	 * Interface to process a received topic from remote.
+	 * @param topic_name
+	 * 	This represents the uORB message Name (topic); This message Name should be
+	 * 	globally unique.
+	 * @param isAdvertisement
+	 * 	Represents if the topic has been advertised or is no longer avialable.
+	 * @return
+	 *  0 = success; This means the messages is successfully handled in the
+	 *  	handler.
+	 *  otherwise = failure.
+	 */
+
+	virtual int16_t process_remote_topic(const char *topic_name, bool isAdvertisement) = 0;
+
 	/**
 	 * Interface to process a received AddSubscription from remote.
 	 * @param messageName

src/modules/uORB/uORBDevices.cpp

@@ -489,6 +489,26 @@ int uORB::DeviceNode::unadvertise(orb_advert_t handle)
 	return PX4_OK;
 }
 
+int16_t uORB::DeviceNode::topic_advertised(const orb_metadata *meta, int priority)
+{
+	uORBCommunicator::IChannel *ch = uORB::Manager::get_instance()->get_uorb_communicator();
+	if (ch != nullptr && meta != nullptr) {
+		return ch->topic_advertised(meta->o_name);
+	}
+	return -1;
+}
+/*
+//TODO: Check if we need this since we only unadvertise when things all shutdown and it doesn't actually remove the device
+int16_t uORB::DeviceNode::topic_unadvertised(const orb_metadata *meta, int priority)
+{
+	uORBCommunicator::IChannel *ch = uORB::Manager::get_instance()->get_uorb_communicator();
+	if (ch != nullptr && meta != nullptr) {
+		return ch->topic_unadvertised(meta->o_name);
+	}
+	return -1;
+}
+*/
+
 pollevent_t
 uORB::DeviceNode::poll_state(device::file_t *filp)
 {

src/modules/uORB/uORBDevices.hpp

@@ -125,6 +125,9 @@ public:
 
 	static int        unadvertise(orb_advert_t handle);
 
+	static int16_t topic_advertised(const orb_metadata *meta, int priority);
+	//static int16_t topic_unadvertised(const orb_metadata *meta, int priority);
+
 	/**
 	 * processes a request for add subscription from remote
 	 * @param rateInHz

src/modules/uORB/uORBManager.cpp

@@ -131,11 +131,15 @@ int uORB::Manager::orb_exists(const struct orb_metadata *meta, int instance)
 		return ERROR;
 	}
 
-#ifdef __PX4_NUTTX
+#if __PX4_NUTTX
 	struct stat buffer;
 	return stat(path, &buffer);
 #else
-	return px4_access(path, F_OK);
+	ret = px4_access(path, F_OK);
+	if (ret == -1 && meta != nullptr && _remote_topics.size() > 0) {
+		ret = (_remote_topics.find(meta->o_name) != _remote_topics.end());
+	}
+	return ret;
 #endif
 }
 
@@ -197,6 +201,9 @@ orb_advert_t uORB::Manager::orb_advertise_multi(const struct orb_metadata *meta,
 		return nullptr;
 	}
 
+	//For remote systems call over and inform them
+	uORB::DeviceNode::topic_advertised(meta, priority);
+
 	/* the advertiser must perform an initial publish to initialise the object */
 	result = orb_publish(meta, advertiser, data);
 
@@ -433,6 +440,23 @@ uORBCommunicator::IChannel *uORB::Manager::get_uorb_communicator(void)
 	return _comm_channel;
 }
 
+//-----------------------------------------------------------------------------
+//-----------------------------------------------------------------------------
+int16_t uORB::Manager::process_remote_topic(const char *topic_name, bool isAdvertisement)
+{
+	warnx("[posix-uORB::Manager::process_remote_topic(%d)] name: %s, isAdver: %d",
+	      __LINE__, topic_name, isAdvertisement);
+	int16_t rc = 0;
+
+	if (isAdvertisement) {
+		_remote_topics.insert(topic_name);
+	} else {
+		_remote_topics.erase(topic_name);
+	}
+
+	return rc;
+}
+
 //-----------------------------------------------------------------------------
 //-----------------------------------------------------------------------------
 int16_t uORB::Manager::process_add_subscription(const char *messageName,

src/modules/uORB/uORBManager.hpp

@@ -410,6 +410,7 @@ private: // data members
 	// the communicator channel instance.
 	uORBCommunicator::IChannel *_comm_channel;
 	ORBSet _remote_subscriber_topics;
+	ORBSet _remote_topics;
 
 	DeviceMaster *_device_masters[Flavor_count]; ///< Allow at most one DeviceMaster per Flavor
 
@@ -417,6 +418,20 @@ private: //class methods
 	Manager();
 	~Manager();
 
+	/**
+	 * Interface to process a received topic from remote.
+	 * @param topic_name
+	 * 	This represents the uORB message Name (topic); This message Name should be
+	 * 	globally unique.
+	 * @param isAdvertisement
+	 * 	Represents if the topic has been advertised or is no longer avialable.
+	 * @return
+	 *  0 = success; This means the messages is successfully handled in the
+	 *  	handler.
+	 *  otherwise = failure.
+	 */
+	virtual int16_t process_remote_topic(const char *topic_name, bool isAdvertisement);
+
 	/**
 	   * Interface to process a received AddSubscription from remote.
 	   * @param messageName