mpd/src/event/EpollBackend.hxx
2021-02-05 17:55:33 +01:00

86 lines
2.1 KiB
C++

/*
* Copyright 2003-2021 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 EVENT_EPOLL_BACKEND_HXX
#define EVENT_EPOLL_BACKEND_HXX
#include "system/EpollFD.hxx"
#include <array>
#include <algorithm>
class EpollBackendResult
{
friend class EpollBackend;
std::array<epoll_event, 16> events;
size_t n_events = 0;
public:
size_t GetSize() const noexcept {
return n_events;
}
unsigned GetEvents(size_t i) const noexcept {
return events[i].events;
}
void *GetObject(size_t i) const noexcept {
return events[i].data.ptr;
}
};
class EpollBackend
{
EpollFD epoll;
EpollBackend(EpollBackend &) = delete;
EpollBackend &operator=(EpollBackend &) = delete;
public:
EpollBackend() = default;
auto ReadEvents(int timeout_ms) noexcept {
EpollBackendResult result;
int ret = epoll.Wait(result.events.data(), result.events.size(),
timeout_ms);
result.n_events = std::max(0, ret);
return result;
}
bool Add(int fd, unsigned events, void *obj) noexcept {
return epoll.Add(fd, events, obj);
}
bool Modify(int fd, unsigned events, void *obj) noexcept {
return epoll.Modify(fd, events, obj);
}
bool Remove(int fd) noexcept {
return epoll.Remove(fd);
}
bool Abandon([[maybe_unused]] int fd) noexcept {
// Nothing to do in this implementation.
// Closed descriptors are automatically unregistered.
return true;
}
};
#endif