89 lines
1.8 KiB
C++
89 lines
1.8 KiB
C++
/*
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* \brief File-system listener
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* \author Norman Feske
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* \date 2012-04-11
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*/
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/*
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* Copyright (C) 2012-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _FILE_SYSTEM__LISTENER_H_
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#define _FILE_SYSTEM__LISTENER_H_
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/* Genode includes */
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#include <file_system_session/rpc_object.h>
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#include <util/list.h>
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#include <base/lock.h>
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#include <base/signal.h>
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namespace File_system {
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typedef ::File_system::Session_rpc_object::Tx::Sink Sink;
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class Listener : public Genode::List<Listener>::Element
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{
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public:
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struct Version { unsigned value; };
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private:
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Genode::Lock _lock { };
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Sink &_sink;
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Node_handle const _handle;
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/*
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* Version at the time when the file was opened
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*/
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Version _handed_out_version;
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/*
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* Version at the time when we issued the most recent notification
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*/
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Version _notified_version = _handed_out_version;
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public:
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Listener(Sink &sink, Node_handle handle, Version handed_out_version)
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: _sink(sink), _handle(handle), _handed_out_version(handed_out_version)
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{ }
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/*
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* Called on close of written files
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*/
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void notify(Version curr_version)
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{
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Genode::Lock::Guard guard(_lock);
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if (curr_version.value == _handed_out_version.value)
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return;
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if (curr_version.value == _notified_version.value)
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return;
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if (_sink.ready_to_ack()) {
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_sink.acknowledge_packet(Packet_descriptor(
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_handle, Packet_descriptor::CONTENT_CHANGED));
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_notified_version = curr_version;
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}
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}
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/*
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* Called during read
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*/
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void handed_out_version(Version version)
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{
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Genode::Lock::Guard guard(_lock);
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_handed_out_version = version;
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}
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};
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}
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#endif /* _FILE_SYSTEM__LISTENER_H_ */
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