101 lines
2.6 KiB
C++
101 lines
2.6 KiB
C++
/*
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* Copyright 2003-2021 The Music Player Daemon Project
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* http://www.musicpd.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* 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, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "PollBackend.hxx"
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#include <cassert>
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PollBackend::PollBackend() noexcept = default;
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PollBackend::~PollBackend() noexcept = default;
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static constexpr auto
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MakePollfd(int fd, short events) noexcept
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{
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struct pollfd pfd{};
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pfd.fd = fd;
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pfd.events = events;
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return pfd;
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}
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bool
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PollBackend::Add(int fd, unsigned events, void *obj) noexcept
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{
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assert(items.find(fd) == items.end());
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const std::size_t index = poll_events.size();
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poll_events.push_back(MakePollfd(fd, events));
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items.emplace(std::piecewise_construct,
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std::forward_as_tuple(fd),
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std::forward_as_tuple(index, obj));
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return true;
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}
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bool
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PollBackend::Modify(int fd, unsigned events, void *obj) noexcept
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{
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auto item_iter = items.find(fd);
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assert(item_iter != items.end());
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auto &item = item_iter->second;
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item.obj = obj;
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auto &e = poll_events[item.index];
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e.events = events;
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e.revents &= events;
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return true;
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}
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bool
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PollBackend::Remove(int fd) noexcept
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{
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auto item_iter = items.find(fd);
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assert(item_iter != items.end());
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const auto &item = item_iter->second;
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std::size_t index = item.index;
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std::size_t last_index = poll_events.size() - 1;
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if (index != last_index) {
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std::swap(poll_events[index], poll_events[last_index]);
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items.find(poll_events[index].fd)->second.index = index;
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}
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poll_events.pop_back();
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items.erase(item_iter);
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return true;
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}
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PollResultGeneric
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PollBackend::ReadEvents(int timeout_ms) noexcept
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{
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int n = poll(poll_events.empty() ? nullptr : &poll_events[0],
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poll_events.size(), timeout_ms);
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PollResultGeneric result;
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for (std::size_t i = 0; n > 0 && i < poll_events.size(); ++i) {
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const auto &e = poll_events[i];
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if (e.revents != 0) {
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auto it = items.find(e.fd);
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assert(it != items.end());
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assert(it->second.index == i);
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result.Add(e.revents, it->second.obj);
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--n;
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}
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}
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return result;
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}
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