genode/os/include/packet_stream_tx/rpc_object.h

/*
 * \brief  Server-side interface for packet-stream transmission
 * \author Norman Feske
 * \date   2010-03-01
 */

/*
 * Copyright (C) 2010-2012 Genode Labs GmbH
 *
 * This file is part of the Genode OS framework, which is distributed
 * under the terms of the GNU General Public License version 2.
 */

#ifndef _INCLUDE__PACKET_STREAM_TX__RPC_OBJECT_H_
#define _INCLUDE__PACKET_STREAM_TX__RPC_OBJECT_H_

#include <packet_stream_tx/packet_stream_tx.h>
#include <base/rpc_server.h>

namespace Packet_stream_tx {

	template <typename CHANNEL>
	class Rpc_object : public Genode::Rpc_object<CHANNEL, Rpc_object<CHANNEL> >
	{
		private:

			Genode::Rpc_entrypoint     &_ep;
			Genode::Capability<CHANNEL> _cap;
			typename CHANNEL::Sink      _sink;

			Genode::Signal_context_capability _sigh_ready_to_ack;
			Genode::Signal_context_capability _sigh_packet_avail;

		public:

			/**
			 * Constructor
			 *
			 * \param ds  dataspace used as communication buffer
			 *            for the transmission packet stream
			 * \param ep  entry point used for serving the channel's RPC
			 *            interface
			 */
			Rpc_object(Genode::Dataspace_capability ds,
			           Genode::Rpc_entrypoint &ep)
			:
				_ep(ep), _cap(_ep.manage(this)), _sink(ds),

				/* init signal handlers with default handlers of sink */
				_sigh_ready_to_ack(_sink.sigh_ready_to_ack()),
				_sigh_packet_avail(_sink.sigh_packet_avail())
			{ }

			/**
			 * Destructor
			 */
			~Rpc_object() { _ep.dissolve(this); }

			/*
			 * The 'sigh_packet_avail()' and 'sigh_ready_to_ack()' functions
			 * may be called at session-creation time to override the default
			 * data-flow signal handlers as provided by the packet-stream sink.
			 * The default handlers let the server block in the event of data
			 * congestion. By installing custom signal handlers, a server
			 * implementation is able to avoid blocking for a single event by
			 * facilitating the use of a select-like mode of operation.
			 *
			 * Note that calling these functions after the finished creation of
			 * the session has no effect because the client queries the signal
			 * handlers only once at session-creation time.
			 */

			/**
			 * Override default handler for server-side ready-to-ack signals
			 */
			void sigh_ready_to_ack(Genode::Signal_context_capability sigh) {
				_sigh_ready_to_ack = sigh; }

			/**
			 * Override default handler for server-side packet-avail signals
			 *
			 * Must be called at constuction time only.
			 */
			void sigh_packet_avail(Genode::Signal_context_capability sigh) {
				_sigh_packet_avail = sigh; }

			typename CHANNEL::Sink *sink() { return &_sink; }

			Genode::Capability<CHANNEL> cap() const { return _cap; }


			/*******************
			 ** RPC functions **
			 *******************/

			Genode::Dataspace_capability dataspace() { return _sink.dataspace(); }

			void sigh_ready_to_submit(Genode::Signal_context_capability sigh) {
				_sink.register_sigh_ready_to_submit(sigh); }

			void sigh_ack_avail(Genode::Signal_context_capability sigh) {
				_sink.register_sigh_ack_avail(sigh); }

			virtual Genode::Signal_context_capability sigh_ready_to_ack() {
				return _sigh_ready_to_ack; }

			virtual Genode::Signal_context_capability sigh_packet_avail() {
				return _sigh_packet_avail; }

	};
}

#endif /* _INCLUDE__PACKET_STREAM_TX__RPC_OBJECT_H_ */