mirror of https://github.com/ArduPilot/ardupilot
128 lines
3.2 KiB
C++
128 lines
3.2 KiB
C++
/*
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* Copyright (C) 2016 Intel Corporation. All rights reserved.
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*
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* This file is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This file is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <unistd.h>
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#include "AP_HAL/utility/RingBuffer.h"
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#include "Semaphores.h"
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namespace Linux {
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class Poller;
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class Pollable {
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friend class Poller;
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public:
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Pollable(int fd) : _fd(fd) { }
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Pollable() { }
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virtual ~Pollable();
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int get_fd() const { return _fd; }
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/* Called whenever the underlying file descriptor has data to be read. */
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virtual void on_can_read() { }
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/*
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* Called whenever the underlying file descriptor is ready to receive new
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* data, i.e. its buffer is not full.
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*/
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virtual void on_can_write() { }
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/*
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* Called when an error occurred and is signaled by the OS - its meaning
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* depends on the file descriptor being used.
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*/
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virtual void on_error() { }
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/*
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* Called when the other side closes its end - the exact meaning
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* depends on the file descriptor being used.
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*/
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virtual void on_hang_up() { }
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protected:
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int _fd = -1;
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};
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/*
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* Internal class to be used inside Poller in order to keep track of requests
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* to wake it up
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*/
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class WakeupPollable : public Pollable {
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friend class Poller;
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public:
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void on_can_read() override;
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};
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class Poller {
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public:
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Poller();
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~Poller() {
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unregister_pollable(&_wakeup);
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if (_epfd >= 0) {
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close(_epfd);
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}
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}
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/*
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* Check if this Poller is not initialized
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*/
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bool operator!() const { return _epfd == -1; }
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/*
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* Check if this Poller is succesfully initialized
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*/
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explicit operator bool() const { return _epfd != -1; }
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/*
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* Register @p in this poller so calls to poll() will wait for
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* events specified in @events argument.
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*/
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bool register_pollable(Pollable *p, uint32_t events);
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/*
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* Unregister @p from this Poller so it doesn't generate any more
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* event. Note that this doesn't destroy @p.
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*/
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void unregister_pollable(const Pollable *p);
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/*
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* Wait for events on all Pollable objects registered with
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* register_pollable(). New Pollable objects can be registered at any
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* time, including when a thread is sleeping on a poll() call.
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*/
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int poll() const;
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/*
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* Wake up the thread sleeping on a poll() call if it is in fact
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* sleeping. Otherwise a nop event is generated and handled. This is
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* usually called from a thread different from the one calling poll().
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*/
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void wakeup() const;
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private:
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int _epfd = -1;
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WakeupPollable _wakeup{};
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};
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}
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