info_receiver.h

#ifndef INFO_RECEIVER_H
#define INFO_RECEIVER_H

#include "common.h"
#include "forward.h"
#include <condition_variable>
#include <mutex>
#include <thread>

namespace lsl {
class inlet_connection;
class stream_info_impl;

/** Internal class of an inlet that is responsible for retrieving the info of the inlet.
 *
 * The actual communication runs in an internal background thread, while the public function
 * (info_receiver::info()) waits for the thread to finish.
 * The public function has an optional timeout after which it gives up, while the background thread
 * continues to do its job (so the next public-function call may succeed within the timeout).
 * The background thread terminates only if the info_receiver is destroyed or the underlying
 * connection is lost or shut down.
 */
class info_receiver {
public:
	/// Construct a new info receiver for a given connection.
	info_receiver(inlet_connection &conn);

	/// Destructor. Stops the background activities.
	~info_receiver();

	/**
	 * Retrieve the complete information of the given stream, including the extended description
	 * (stream_info::desc() field).
	 * @param timeout Timeout of the operation (default: no timeout).
	 * @throws timeout_error (if the timeout expires), or lost_error (if the stream source has been
	 * lost).
	 */
	const stream_info_impl &info(double timeout = FOREVER);

private:
	/// The info reader thread.
	void info_thread();

	/// reference to the underlying connection
	inlet_connection &conn_;

	/// background reader thread and the data generated by it
	/// pulls the info in the background
	std::thread info_thread_;
	/// the full stream_info_impl object (retrieved by the info thread)
	stream_info_impl_p fullinfo_;
	/// mutex to protect the fullinfo
	std::mutex fullinfo_mut_;
	/// condition variable to indicate that an update for the fullinfo is available
	std::condition_variable fullinfo_upd_;
};

} // namespace lsl

#endif