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0ed68a56b7
This patch changes both the Input::Session interface and the skeleton
for the server-side implementation of this interface
('input/component.h').
The Input::Session interface offers a new 'sigh' function, which can be
called be the client to register a signal handler. The signal handler
gets notified on the arrival of new input. This alleviates the need to
poll for input events at the client side.
The server-side skeleton for implementing input services underwent a
redesign to make it more modular and robust. I.e., there are no
global functions needed at the server side and the event-queue
enable/disable mechanism is implemented at a central place (in the root
component) rather than inside each driver.
Fixes #46
71 lines
1.7 KiB
C++
71 lines
1.7 KiB
C++
/*
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* \brief Input root component
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* \author Norman Feske
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* \date 2014-05-31
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*/
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/*
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* Copyright (C) 2014 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 General Public License version 2.
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*/
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#ifndef _INPUT__ROOT_H_
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#define _INPUT__ROOT_H_
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/* Genode includes */
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#include <os/static_root.h>
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#include <input/component.h>
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namespace Input { class Root_component; }
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/*
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* This input root component tracks if the session has been opened. If a client
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* is connected, the 'Event_queue::enabled' gets enabled. This is useful to
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* omit the enqueuing of input events into the event queue before any client is
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* interested in receiving input events. If we would not drop such early input
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* events, the queue might overflow when input events are generated at boot
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* times.
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*/
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class Input::Root_component : public Genode::Static_root<Input::Session>
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{
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private:
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Genode::Rpc_entrypoint &_ep;
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Input::Session_component &_session;
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public:
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Root_component(Genode::Rpc_entrypoint &ep, Input::Session_component &session)
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:
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Static_root<Input::Session>(ep.manage(&session)),
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_ep(ep), _session(session)
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{ }
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~Root_component()
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{
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_ep.dissolve(&_session);
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}
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Genode::Capability<Genode::Session>
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session(Genode::Root::Session_args const &args,
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Genode::Affinity const &affinity) override
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{
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if (_session.event_queue().enabled())
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throw Root::Unavailable();
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_session.event_queue().enabled(true);
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return Static_root<Input::Session>::session(args, affinity);
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}
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void close(Genode::Capability<Session>)
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{
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_session.event_queue().enabled(false);
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}
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};
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#endif /* _INPUT__ROOT_H_ */
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