TLA Line data Source code
1 : //
2 : // Copyright (c) 2026 Steve Gerbino
3 : //
4 : // Distributed under the Boost Software License, Version 1.0. (See accompanying
5 : // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 : //
7 : // Official repository: https://github.com/cppalliance/corosio
8 : //
9 :
10 : #ifndef BOOST_COROSIO_NATIVE_NATIVE_STREAM_FILE_HPP
11 : #define BOOST_COROSIO_NATIVE_NATIVE_STREAM_FILE_HPP
12 :
13 : #include <boost/corosio/stream_file.hpp>
14 : #include <boost/corosio/backend.hpp>
15 :
16 : #ifndef BOOST_COROSIO_MRDOCS
17 : #if BOOST_COROSIO_HAS_EPOLL || BOOST_COROSIO_HAS_SELECT || \
18 : BOOST_COROSIO_HAS_KQUEUE
19 : #include <boost/corosio/native/detail/posix/posix_stream_file_service.hpp>
20 : #endif
21 :
22 : #if BOOST_COROSIO_HAS_IO_URING
23 : #include <boost/corosio/native/detail/io_uring/io_uring_stream_file.hpp>
24 : #endif
25 :
26 : #if BOOST_COROSIO_HAS_IOCP
27 : #include <boost/corosio/native/detail/iocp/win_file_service.hpp>
28 : #endif
29 : #endif // !BOOST_COROSIO_MRDOCS
30 :
31 : namespace boost::corosio {
32 :
33 : /** A sequential file with devirtualized async I/O operations.
34 :
35 : This class template inherits from @ref stream_file and shadows
36 : `read_some` / `write_some` with versions that call the backend
37 : implementation directly, allowing the compiler to inline through
38 : the entire call chain.
39 :
40 : Non-async operations (`open`, `close`, `size`, `resize`, `seek`,
41 : `sync_data`, `sync_all`) remain unchanged and dispatch through
42 : the compiled library.
43 :
44 : A `native_stream_file` IS-A `stream_file` and can be passed to
45 : any function expecting `stream_file&` or `io_stream&`, in which
46 : case virtual dispatch is used transparently.
47 :
48 : @note On POSIX platforms, file I/O is dispatched to a thread
49 : pool regardless of the chosen reactor backend, so all three
50 : reactor tags (`epoll`, `select`, `kqueue`) resolve to the same
51 : underlying implementation. The `Backend` template parameter
52 : exists for API symmetry with @ref native_tcp_socket and friends.
53 : The vtable savings are smaller relative to the thread-pool /
54 : overlapped-I/O cost than they are for socket operations.
55 :
56 : @tparam Backend A backend tag value (e.g., `epoll`, `iocp`).
57 :
58 : @par Thread Safety
59 : Same as @ref stream_file.
60 :
61 : @par Example
62 : @code
63 : #include <boost/corosio/native/native_stream_file.hpp>
64 :
65 : native_io_context<epoll> ctx;
66 : native_stream_file<epoll> f(ctx);
67 : f.open("data.bin", file_base::read_only);
68 : char buf[4096];
69 : auto [ec, n] = co_await f.read_some(
70 : capy::mutable_buffer(buf, sizeof(buf)));
71 : @endcode
72 :
73 : @see stream_file, epoll_t, iocp_t
74 : */
75 : template<auto Backend>
76 : class native_stream_file : public stream_file
77 : {
78 : using backend_type = decltype(Backend);
79 : using impl_type = typename backend_type::stream_file_type;
80 : using service_type = typename backend_type::stream_file_service_type;
81 :
82 HIT 4 : impl_type& get_impl() noexcept
83 : {
84 4 : return *static_cast<impl_type*>(h_.get());
85 : }
86 :
87 : template<class MutableBufferSequence>
88 : struct native_read_awaitable
89 : {
90 : native_stream_file& self_;
91 : MutableBufferSequence buffers_;
92 : std::stop_token token_;
93 : mutable std::error_code ec_;
94 : mutable std::size_t bytes_transferred_ = 0;
95 :
96 2 : native_read_awaitable(
97 : native_stream_file& self,
98 : MutableBufferSequence buffers) noexcept
99 2 : : self_(self)
100 2 : , buffers_(std::move(buffers))
101 : {
102 2 : }
103 :
104 2 : bool await_ready() const noexcept
105 : {
106 2 : return token_.stop_requested();
107 : }
108 :
109 2 : capy::io_result<std::size_t> await_resume() const noexcept
110 : {
111 2 : if (token_.stop_requested())
112 MIS 0 : return {make_error_code(std::errc::operation_canceled), 0};
113 HIT 2 : return {ec_, bytes_transferred_};
114 : }
115 :
116 2 : auto await_suspend(std::coroutine_handle<> h, capy::io_env const* env)
117 : -> std::coroutine_handle<>
118 : {
119 2 : token_ = env->stop_token;
120 6 : return self_.get_impl().read_some(
121 6 : h, env->executor, buffers_, token_, &ec_, &bytes_transferred_);
122 : }
123 : };
124 :
125 : template<class ConstBufferSequence>
126 : struct native_write_awaitable
127 : {
128 : native_stream_file& self_;
129 : ConstBufferSequence buffers_;
130 : std::stop_token token_;
131 : mutable std::error_code ec_;
132 : mutable std::size_t bytes_transferred_ = 0;
133 :
134 2 : native_write_awaitable(
135 : native_stream_file& self,
136 : ConstBufferSequence buffers) noexcept
137 2 : : self_(self)
138 2 : , buffers_(std::move(buffers))
139 : {
140 2 : }
141 :
142 2 : bool await_ready() const noexcept
143 : {
144 2 : return token_.stop_requested();
145 : }
146 :
147 2 : capy::io_result<std::size_t> await_resume() const noexcept
148 : {
149 2 : if (token_.stop_requested())
150 MIS 0 : return {make_error_code(std::errc::operation_canceled), 0};
151 HIT 2 : return {ec_, bytes_transferred_};
152 : }
153 :
154 2 : auto await_suspend(std::coroutine_handle<> h, capy::io_env const* env)
155 : -> std::coroutine_handle<>
156 : {
157 2 : token_ = env->stop_token;
158 6 : return self_.get_impl().write_some(
159 6 : h, env->executor, buffers_, token_, &ec_, &bytes_transferred_);
160 : }
161 : };
162 :
163 : public:
164 : /** Construct a native stream file from an execution context.
165 :
166 : @param ctx The execution context that will own this file.
167 : */
168 10 : explicit native_stream_file(capy::execution_context& ctx)
169 10 : : io_object(create_handle<service_type>(ctx))
170 : {
171 10 : }
172 :
173 : /** Construct a native stream file from an executor.
174 :
175 : @param ex The executor whose context will own this file.
176 : */
177 : template<class Ex>
178 : requires(!std::same_as<std::remove_cvref_t<Ex>, native_stream_file>) &&
179 : capy::Executor<Ex>
180 : explicit native_stream_file(Ex const& ex) : native_stream_file(ex.context())
181 : {
182 : }
183 :
184 : /// Move construct.
185 : native_stream_file(native_stream_file&&) noexcept = default;
186 :
187 : /// Move assign.
188 : native_stream_file& operator=(native_stream_file&&) noexcept = default;
189 :
190 : native_stream_file(native_stream_file const&) = delete;
191 : native_stream_file& operator=(native_stream_file const&) = delete;
192 :
193 : /** Asynchronously read data from the file.
194 :
195 : Calls the backend implementation directly, bypassing virtual
196 : dispatch. Otherwise identical to @ref io_stream::read_some.
197 : */
198 : template<capy::MutableBufferSequence MB>
199 2 : auto read_some(MB const& buffers)
200 : {
201 2 : return native_read_awaitable<MB>(*this, buffers);
202 : }
203 :
204 : /** Asynchronously write data to the file.
205 :
206 : Calls the backend implementation directly, bypassing virtual
207 : dispatch. Otherwise identical to @ref io_stream::write_some.
208 : */
209 : template<capy::ConstBufferSequence CB>
210 2 : auto write_some(CB const& buffers)
211 : {
212 2 : return native_write_awaitable<CB>(*this, buffers);
213 : }
214 : };
215 :
216 : } // namespace boost::corosio
217 :
218 : #endif // BOOST_COROSIO_NATIVE_NATIVE_STREAM_FILE_HPP
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