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/*
* Copyright 2003-2017 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_SOCKET_MONITOR_HXX
#define MPD_SOCKET_MONITOR_HXX
#include "check.h"
#include "PollGroup.hxx"
#include "net/SocketDescriptor.hxx"
#include <type_traits>
#include <assert.h>
#include <stddef.h>
#ifdef WIN32
/* ERROR is a WIN32 macro that poisons our namespace; this is a kludge
to allow us to use it anyway */
#ifdef ERROR
#undef ERROR
#endif
#endif
class EventLoop;
/**
* Monitor events on a socket. Call Schedule() to announce events
* you're interested in, or Cancel() to cancel your subscription. The
* #EventLoop will invoke virtual method OnSocketReady() as soon as
* any of the subscribed events are ready.
*
* This class does not feel responsible for closing the socket. Call
* Close() to do it manually.
*
* This class is not thread-safe, all methods must be called from the
* thread that runs the #EventLoop, except where explicitly documented
* as thread-safe.
*/
class SocketMonitor {
SocketDescriptor fd;
EventLoop &loop;
/**
* A bit mask of events that is currently registered in the EventLoop.
*/
unsigned scheduled_flags;
public:
static constexpr unsigned READ = PollGroup::READ;
static constexpr unsigned WRITE = PollGroup::WRITE;
static constexpr unsigned ERROR = PollGroup::ERROR;
static constexpr unsigned HANGUP = PollGroup::HANGUP;
typedef std::make_signed<size_t>::type ssize_t;
SocketMonitor(EventLoop &_loop)
:fd(-1), loop(_loop), scheduled_flags(0) {}
SocketMonitor(SocketDescriptor _fd, EventLoop &_loop)
:fd(_fd), loop(_loop), scheduled_flags(0) {}
~SocketMonitor();
EventLoop &GetEventLoop() {
return loop;
}
bool IsDefined() const {
return fd.IsDefined();
}
SocketDescriptor Get() const {
assert(IsDefined());
return fd;
}
void Open(SocketDescriptor _fd);
/**
* "Steal" the socket descriptor. This abandons the socket
* and returns it.
*/
SocketDescriptor Steal();
/**
* Somebody has closed the socket. Unregister this object.
*/
void Abandon();
void Close();
unsigned GetScheduledFlags() const {
assert(IsDefined());
return scheduled_flags;
}
void Schedule(unsigned flags);
void Cancel() {
Schedule(0);
}
void ScheduleRead() {
Schedule(GetScheduledFlags() | READ | HANGUP | ERROR);
}
void ScheduleWrite() {
Schedule(GetScheduledFlags() | WRITE);
}
void CancelRead() {
Schedule(GetScheduledFlags() & ~(READ|HANGUP|ERROR));
}
void CancelWrite() {
Schedule(GetScheduledFlags() & ~WRITE);
}
ssize_t Read(void *data, size_t length);
ssize_t Write(const void *data, size_t length);
protected:
/**
* @return false if the socket has been closed
*/
virtual bool OnSocketReady(unsigned flags) = 0;
public:
void Dispatch(unsigned flags);
};
#endif
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