Seastar
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io_sink.hh
1/*
2 * This file is open source software, licensed to you under the terms
3 * of the Apache License, Version 2.0 (the "License"). See the NOTICE file
4 * distributed with this work for additional information regarding copyright
5 * ownership. You may not use this file except in compliance with the License.
6 *
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing,
12 * software distributed under the License is distributed on an
13 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14 * KIND, either express or implied. See the License for the
15 * specific language governing permissions and limitations
16 * under the License.
17 */
18/*
19 * Copyright 2021 ScyllaDB
20 */
21
22#pragma once
23
24#include <seastar/core/chunked_fifo.hh>
25#include <seastar/core/internal/io_request.hh>
26
27#include <concepts>
28#include <cstddef>
29#include <type_traits>
30#include <utility>
31
32namespace seastar {
33
34class io_completion;
35
36namespace internal {
37
38class io_sink;
39
40class pending_io_request : private internal::io_request {
41 friend class io_sink;
42 io_completion* _completion;
43
44public:
45 pending_io_request(internal::io_request req, io_completion* desc) noexcept
46 : io_request(std::move(req))
47 , _completion(desc)
48 { }
49};
50
51class io_sink {
52 chunked_fifo<pending_io_request> _pending_io;
53public:
54 void submit(io_completion* desc, internal::io_request req) noexcept;
55
56 template <typename Fn>
57 // Fn should return whether the request was consumed and
58 // draining should try to drain more
59 requires std::is_invocable_r<bool, Fn, internal::io_request&, io_completion*>::value
60 size_t drain(Fn&& consume) {
61 size_t drained = 0;
62
63 for (auto& req : _pending_io) {
64 if (!consume(req, req._completion)) {
65 break;
66 }
67 drained++;
68 }
69
70 _pending_io.pop_front_n(drained);
71 return drained;
72 }
73};
74
75} // namespace internal
76
77} // namespace seastar
Seastar API namespace.
Definition: abort_on_ebadf.hh:26