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/*
* 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.
*/
#pragma once
#include "io/FileDescriptor.hxx"
#include <liburing.h>
namespace Uring {
/**
* Low-level C++ wrapper for a `struct io_uring`. It provides simple
* wrappers to liburing functions and throws std::system_error on
* errors.
*/
class Ring {
struct io_uring ring;
public:
Ring(unsigned entries, unsigned flags);
~Ring() noexcept {
io_uring_queue_exit(&ring);
}
Ring(const Ring &) = delete;
Ring &operator=(const Ring &) = delete;
FileDescriptor GetFileDescriptor() const noexcept {
return FileDescriptor(ring.ring_fd);
}
struct io_uring_sqe *GetSubmitEntry() noexcept {
return io_uring_get_sqe(&ring);
}
void Submit();
struct io_uring_cqe *WaitCompletion();
/**
* @return a completion queue entry or nullptr on EAGAIN
*/
struct io_uring_cqe *PeekCompletion();
void SeenCompletion(struct io_uring_cqe &cqe) noexcept {
io_uring_cqe_seen(&ring, &cqe);
}
};
} // namespace Uring