138 lines
3.3 KiB
C++
138 lines
3.3 KiB
C++
/*
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* Copyright 2003-2018 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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#ifndef MPD_SOCKET_MONITOR_HXX
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#define MPD_SOCKET_MONITOR_HXX
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#include "PollGroup.hxx"
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#include "net/SocketDescriptor.hxx"
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#include <type_traits>
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#include <assert.h>
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#include <stddef.h>
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class EventLoop;
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/**
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* Monitor events on a socket. Call Schedule() to announce events
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* you're interested in, or Cancel() to cancel your subscription. The
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* #EventLoop will invoke virtual method OnSocketReady() as soon as
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* any of the subscribed events are ready.
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*
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* This class does not feel responsible for closing the socket. Call
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* Close() to do it manually.
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*
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* This class is not thread-safe, all methods must be called from the
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* thread that runs the #EventLoop, except where explicitly documented
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* as thread-safe.
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*/
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class SocketMonitor {
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SocketDescriptor fd = SocketDescriptor::Undefined();
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EventLoop &loop;
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/**
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* A bit mask of events that is currently registered in the EventLoop.
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*/
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unsigned scheduled_flags = 0;
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public:
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static constexpr unsigned READ = PollGroup::READ;
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static constexpr unsigned WRITE = PollGroup::WRITE;
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static constexpr unsigned ERROR = PollGroup::ERROR;
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static constexpr unsigned HANGUP = PollGroup::HANGUP;
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typedef std::make_signed<size_t>::type ssize_t;
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explicit SocketMonitor(EventLoop &_loop) noexcept
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:loop(_loop) {}
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SocketMonitor(SocketDescriptor _fd, EventLoop &_loop) noexcept
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:fd(_fd), loop(_loop) {}
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~SocketMonitor() noexcept;
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auto &GetEventLoop() const noexcept {
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return loop;
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}
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bool IsDefined() const noexcept {
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return fd.IsDefined();
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}
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SocketDescriptor GetSocket() const noexcept {
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assert(IsDefined());
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return fd;
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}
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void Open(SocketDescriptor _fd) noexcept;
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/**
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* "Steal" the socket descriptor. This abandons the socket
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* and returns it.
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*/
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SocketDescriptor Steal() noexcept;
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void Close() noexcept;
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unsigned GetScheduledFlags() const noexcept {
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assert(IsDefined());
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return scheduled_flags;
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}
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/**
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* @return true on success, false on error (with errno set if
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* USE_EPOLL is defined)
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*/
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bool Schedule(unsigned flags) noexcept;
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void Cancel() noexcept {
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Schedule(0);
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}
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bool ScheduleRead() noexcept {
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return Schedule(GetScheduledFlags() | READ);
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}
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bool ScheduleWrite() noexcept {
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return Schedule(GetScheduledFlags() | WRITE);
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}
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void CancelRead() noexcept {
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Schedule(GetScheduledFlags() & ~READ);
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}
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void CancelWrite() noexcept {
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Schedule(GetScheduledFlags() & ~WRITE);
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}
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protected:
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/**
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* @return false if the socket has been closed
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*/
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virtual bool OnSocketReady(unsigned flags) noexcept = 0;
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public:
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void Dispatch(unsigned flags) noexcept;
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};
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#endif
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