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/**
 * @file mavlink_shell.h
 * A shell to be used via MAVLink
 *
 * @author Beat Küng <beat-kueng@gmx.net>
 */


#include <stddef.h>
#include <stdint.h>
#include <px4_platform_common/tasks.h>

#pragma once

class MavlinkShell
{
public:
	MavlinkShell() = default;

	~MavlinkShell();

	/**
	 * Start the mavlink shell.
	 *
	 * @return		0 on success.
	 */
	int		start();

	/**
	 * Write to the shell
	 * @return number of written bytes
	 */
	size_t write(uint8_t *buffer, size_t len);

	/**
	 * Read from the shell. This is blocking, if 0 bytes are available, this will block.
	 * @param len buffer length
	 * @return number of bytes read.
	 */
	size_t read(uint8_t *buffer, size_t len);

	/**
	 * Get the number of bytes that can be read.
	 */
	size_t available();

private:

	int _to_shell_fd = -1; /** fd to write to the shell */
	int _from_shell_fd = -1; /** fd to read from the shell */
	int _shell_fds[2] = { -1, -1}; /** stdin & out used by the shell */
	px4_task_t _task;

	static int shell_start_thread(int argc, char *argv[]);

	/* do not allow copying this class */
	MavlinkShell(const MavlinkShell &) = delete;
	MavlinkShell operator=(const MavlinkShell &) = delete;
};