/*
 * Copyright 2020 CM4all GmbH
 * All rights reserved.
 *
 * author: Max Kellermann <mk@cm4all.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the
 * distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "Ring.hxx"
#include "system/Error.hxx"

namespace Uring {

Ring::Ring(unsigned entries, unsigned flags)
{
	int error = io_uring_queue_init(entries, &ring, flags);
	if (error < 0)
		throw MakeErrno(-error, "io_uring_queue_init() failed");
}

void
Ring::Submit()
{
	int error = io_uring_submit(&ring);
	if (error < 0)
		throw MakeErrno(-error, "io_uring_submit() failed");
}

struct io_uring_cqe *
Ring::WaitCompletion()
{
	struct io_uring_cqe *cqe;
	int error = io_uring_wait_cqe(&ring, &cqe);
	if (error < 0) {
		if (error == -EAGAIN)
			return nullptr;

		throw MakeErrno(-error, "io_uring_wait_cqe() failed");
	}

	return cqe;
}

struct io_uring_cqe *
Ring::PeekCompletion()
{
	struct io_uring_cqe *cqe;
	int error = io_uring_peek_cqe(&ring, &cqe);
	if (error < 0) {
		if (error == -EAGAIN)
			return nullptr;

		throw MakeErrno(-error, "io_uring_peek_cqe() failed");
	}

	return cqe;
}

} // namespace Uring