Files
mpd/src/io/uring/ReadOperation.cxx
Max Kellermann 799032505e io/uring/Queue: add method RequireSubmitEntry()
Fixes assertion failure when the submit queue is empty.
2021-12-03 13:58:39 +01:00

70 lines
2.1 KiB
C++

/*
* Copyright 2020 Max Kellermann <max.kellermann@gmail.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 "ReadOperation.hxx"
#include "Queue.hxx"
#include "io/FileDescriptor.hxx"
#include <cassert>
namespace Uring {
void
ReadOperation::Start(Queue &queue, FileDescriptor fd, off_t offset,
std::size_t size, ReadHandler &_handler) noexcept
{
assert(!buffer);
handler = &_handler;
buffer = std::make_unique<std::byte[]>(size);
auto &s = queue.RequireSubmitEntry();
iov.iov_base = buffer.get();
iov.iov_len = size;
io_uring_prep_readv(&s, fd.Get(), &iov, 1, offset);
queue.Push(s, *this);
}
void
ReadOperation::OnUringCompletion(int res) noexcept
{
if (handler == nullptr)
/* operation was canceled */
delete this;
else if (res >= 0)
handler->OnRead(std::move(buffer), res);
else
handler->OnReadError(-res);
}
} // namespace Uring