mavlink: add MavlinkULog class to receive ulog data from the logger

src/modules/mavlink/mavlink_ulog.h

@@ -0,0 +1,126 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 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.
+ * 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 mavlink_ulog.h
+ * ULog data streaming via MAVLink
+ *
+ * @author Beat Küng <beat-kueng@gmx.net>
+ */
+
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+#include <px4_tasks.h>
+#include <px4_sem.h>
+#include <drivers/drv_hrt.h>
+
+#include <uORB/topics/ulog_stream.h>
+#include <uORB/topics/ulog_stream_ack.h>
+
+#include "mavlink_bridge_header.h"
+
+/**
+ * @class MavlinkULog
+ * ULog streaming class. At most one instance (stream) can exist, assigned to a specific mavlink channel.
+ */
+class MavlinkULog
+{
+public:
+	/**
+	 * initialize: call this once on startup (this function is not thread-safe!)
+	 */
+	static void initialize();
+
+	/**
+	 * try to start a new stream. This fails if a stream is already running.
+	 * thread-safe
+	 * @return instance, or nullptr
+	 */
+	static MavlinkULog *try_start();
+
+	/**
+	 * stop the stream. It also deletes the singleton object, so make sure cleanup
+	 * all pointers to it.
+	 * thread-safe
+	 */
+	void stop();
+
+	/**
+	 * periodic update method: check for ulog stream messages and handle retransmission.
+	 * @return 0 on success, <0 otherwise
+	 */
+	int handle_update(mavlink_channel_t channel);
+
+	/** ack from mavlink for a data message */
+	void handle_ack(mavlink_logging_ack_t ack);
+
+	/** this is called when we got an vehicle_command_ack from the logger */
+	void start_ack_received();
+
+private:
+
+	MavlinkULog();
+
+	~MavlinkULog();
+
+	static void lock()
+	{
+		do {} while (sem_wait(&_lock) != 0);
+	}
+
+	static void unlock()
+	{
+		sem_post(&_lock);
+	}
+
+	void publish_ack(uint16_t sequence);
+
+	static sem_t _lock;
+	static bool _init;
+	static MavlinkULog *_instance;
+
+	int _ulog_stream_sub = -1;
+	orb_advert_t _ulog_stream_ack_pub = nullptr;
+	uint16_t _wait_for_ack_sequence;
+	uint8_t _sent_tries = 0;
+	volatile bool _ack_received = false; ///< set to true if a matching ack received
+	hrt_abstime _last_sent_time = 0; ///< last time we sent a message that requires an ack
+	ulog_stream_s _ulog_data;
+	bool _waiting_for_initial_ack = false;
+
+	/* do not allow copying this class */
+	MavlinkULog(const MavlinkULog &) = delete;
+	MavlinkULog operator=(const MavlinkULog &) = delete;
+};