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/*
* Copyright (C) 2003-2013 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MPD_WAKE_FD_HXX
#define MPD_WAKE_FD_HXX
#include "check.h"
#include <assert.h>
/**
* This class can be used to wake up an I/O event loop.
*
* For optimization purposes, this class does not have a constructor
* or a destructor.
*/
class WakeFD {
int fds[2];
public:
#ifdef NDEBUG
WakeFD() = default;
#else
WakeFD():fds{-1, -1} {};
#endif
WakeFD(const WakeFD &other) = delete;
WakeFD &operator=(const WakeFD &other) = delete;
bool Create();
void Destroy();
int Get() const {
assert(fds[0] >= 0);
#ifndef HAVE_EVENTFD
assert(fds[1] >= 0);
#endif
return fds[0];
}
/**
* Checks if Write() was called at least once since the last
* Read() call.
*/
bool Read();
/**
* Wakes up the reader. Multiple calls to this function will
* be combined to one wakeup.
*/
void Write();
private:
#ifdef HAVE_EVENTFD
bool IsEventFD() {
assert(fds[0] >= 0);
return fds[1] == -2;
}
#endif
};
#endif /* MAIN_NOTIFY_H */
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