mpd/src/event/SocketMonitor.cxx

/*
 * 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.
 */

#include "config.h"
#include "SocketMonitor.hxx"
#include "Loop.hxx"
#include "fd_util.h"
#include "gcc.h"

#include <assert.h>

/*
 * GSource methods
 *
 */

gboolean
SocketMonitor::Prepare(gcc_unused GSource *source, gcc_unused gint *timeout_r)
{
	return false;
}

gboolean
SocketMonitor::Check(GSource *_source)
{
	const Source &source = *(const Source *)_source;
	const SocketMonitor &monitor = *source.monitor;
	assert(_source == &monitor.source->base);

	return monitor.Check();
}

gboolean
SocketMonitor::Dispatch(GSource *_source,
			gcc_unused GSourceFunc callback,
			gcc_unused gpointer user_data)
{
	Source &source = *(Source *)_source;
	SocketMonitor &monitor = *source.monitor;
	assert(_source == &monitor.source->base);

	monitor.Dispatch();
	return true;
}

/**
 * The vtable for our GSource implementation.  Unfortunately, we
 * cannot declare it "const", because g_source_new() takes a non-const
 * pointer, for whatever reason.
 */
static GSourceFuncs socket_monitor_source_funcs = {
	SocketMonitor::Prepare,
	SocketMonitor::Check,
	SocketMonitor::Dispatch,
	nullptr,
	nullptr,
	nullptr,
};

SocketMonitor::SocketMonitor(int _fd, EventLoop &_loop)
	:fd(-1), loop(_loop),
	 source(nullptr) {
	assert(_fd >= 0);

	Open(_fd);
}

SocketMonitor::~SocketMonitor()
{
	if (IsDefined())
		Close();
}

void
SocketMonitor::Open(int _fd)
{
	assert(fd < 0);
	assert(source == nullptr);
	assert(_fd >= 0);

	fd = _fd;
	poll = {fd, 0, 0};

	source = (Source *)g_source_new(&socket_monitor_source_funcs,
					sizeof(*source));
	source->monitor = this;

	g_source_attach(&source->base, loop.GetContext());
	g_source_add_poll(&source->base, &poll);
}

int
SocketMonitor::Steal()
{
	assert(IsDefined());

	Cancel();

	int result = fd;
	fd = -1;

	g_source_destroy(&source->base);
	g_source_unref(&source->base);
	source = nullptr;

	return result;
}

void
SocketMonitor::Close()
{
	close_socket(Steal());
}