mavlink: bring buffering for log messages back

src/modules/mavlink/mavlink_main.cpp

@@ -1637,6 +1637,8 @@ Mavlink::task_main(int argc, char *argv[])
 	uint64_t status_time = 0;
 	MavlinkOrbSubscription *ack_sub = add_orb_subscription(ORB_ID(vehicle_command_ack));
 	uint64_t ack_time = 0;
+	MavlinkOrbSubscription *mavlink_log_sub = add_orb_subscription(ORB_ID(mavlink_log));
+	uint64_t mavlink_log_time = 0;
 
 	struct vehicle_status_s status;
 	status_sub->update(&status_time, &status);
@@ -1875,6 +1877,11 @@ Mavlink::task_main(int argc, char *argv[])
 			send_message(MAVLINK_MSG_ID_COMMAND_ACK, &msg);
 		}
 
+		struct mavlink_log_s mavlink_log;
+		if (mavlink_log_sub->update(&mavlink_log_time, &mavlink_log)) {
+			_logbuffer.put(&mavlink_log);
+		}
+
 		/* check for requested subscriptions */
 		if (_subscribe_to_stream != nullptr) {
 			if (OK == configure_stream(_subscribe_to_stream, _subscribe_to_stream_rate)) {

src/modules/mavlink/mavlink_messages.cpp

@@ -365,35 +365,45 @@ public:
 	}
 
 private:
-	MavlinkOrbSubscription *_mavlink_log_sub;
-	uint64_t _mavlink_log_time;
-
 	/* do not allow top copying this class */
 	MavlinkStreamStatustext(MavlinkStreamStatustext &);
 	MavlinkStreamStatustext& operator = (const MavlinkStreamStatustext &);
 
 	unsigned write_err_count = 0;
 	static const unsigned write_err_threshold = 5;
+#ifndef __PX4_QURT
 	FILE *fp = nullptr;
+#endif
 
 protected:
-	explicit MavlinkStreamStatustext(Mavlink *mavlink) : MavlinkStream(mavlink),
-		_mavlink_log_sub(_mavlink->add_orb_subscription(ORB_ID(mavlink_log)))
+	explicit MavlinkStreamStatustext(Mavlink *mavlink) : MavlinkStream(mavlink)
 	{}
 
+	~MavlinkStreamStatustext() {
+#ifndef __PX4_QURT
+		if (fp) {
+			fclose(fp);
+		}
+#endif
+	}
+
+
 	void send(const hrt_abstime t)
 	{
-		struct mavlink_log_s mavlink_log;
+		if (!_mavlink->get_logbuffer()->empty()) {
 
-		if (_mavlink_log_sub->update(&_mavlink_log_time, &mavlink_log)) {
+			struct mavlink_log_s mavlink_log;
+			if (_mavlink->get_logbuffer()->get(&mavlink_log)) {
 
 				mavlink_statustext_t msg;
 				msg.severity = mavlink_log.severity;
-
 				strncpy(msg.text, (const char *)mavlink_log.text, sizeof(msg.text));
 
 				_mavlink->send_message(MAVLINK_MSG_ID_STATUSTEXT, &msg);
 
+
+// TODO: the logging doesn't work on Snapdragon yet because of file paths.
+#ifndef __PX4_QURT
 			/* write log messages in first instance to disk */
 			if (_mavlink->get_instance_id() == 0) {
 				if (fp) {
@@ -440,6 +450,8 @@ protected:
 				}
 			}
 		}
+	}
+#endif
 };
 
 class MavlinkStreamCommandLong : public MavlinkStream