genode/repos/os/include/file_system/open_node.h
Emery Hemingway 366913c146 ram_fs: unmark modification from nodes that have been synced
Removed the modified mark from handles that have been written to when
they are synced, otherwise a notification would be sent again when the
handle is closed.

Ref #2839
2018-06-29 10:44:54 +02:00

117 lines
2.8 KiB
C++

/*
* \brief Representation of an open file system node within the component
* \author Christian Prochaska
* \date 2017-06-09
*/
/*
* Copyright (C) 2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _OPEN_NODE_H_
#define _OPEN_NODE_H_
/* Genode includes */
#include <file_system/listener.h>
#include <file_system_session/file_system_session.h>
namespace File_system {
/*
* \param NODE component-specific node type
*/
template <typename NODE> class Open_node;
}
template <typename NODE>
class File_system::Open_node : public File_system::Node
{
private:
Genode::Id_space<File_system::Node>::Element _element;
Genode::Weak_ptr<NODE> _node;
Genode::Constructible<File_system::Listener> _listener { };
Listener::Version const _version_when_opened { _node_version(_node) };
/*
* Flag to track whether the underlying file-system node was
* modified via this 'Open_node'. That is, if closing the 'Open_node'
* should notify listeners of the file.
*/
bool _was_written = false;
static Listener::Version const _node_version(Genode::Weak_ptr<NODE> node)
{
Genode::Locked_ptr<NODE> locked_node { node };
if (locked_node.valid())
return locked_node->curr_version();
else
return Listener::Version { 0 };
}
public:
Open_node(Genode::Weak_ptr<NODE> node,
Genode::Id_space<File_system::Node> &id_space)
: _element(*this, id_space), _node(node) { }
~Open_node()
{
Genode::Locked_ptr<NODE> node { _node };
if (_listener.constructed()) {
if (node.valid())
node->remove_listener(&*_listener);
_listener.destruct();
}
/*
* Notify remaining listeners about the changed file
*/
if (_was_written && node.valid()) {
node->notify_listeners();
}
}
Genode::Weak_ptr<NODE>&node() { return _node; }
File_system::Listener &listener() { return *_listener; }
Genode::Id_space<File_system::Node>::Id id() { return _element.id(); }
/**
* Register packet stream sink to be notified of node changes
*/
void register_notify(File_system::Sink &sink)
{
Genode::Locked_ptr<NODE> node { _node };
/*
* If there was already a handler registered for the node,
* remove the old handler.
*/
if (_listener.constructed()) {
if (node.valid())
node->remove_listener(&*_listener);
_listener.destruct();
}
/*
* Register new handler
*/
if (node.valid()) {
_listener.construct(sink, id(), _version_when_opened);
node->add_listener(&*_listener);
}
}
void mark_as_written() { _was_written = true; }
void unmark_as_written() { _was_written = false; }
};
#endif /* _OPEN_NODE_H_ */