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_RANDOM_ACCESS_FILE_HPP
11 : #define BOOST_COROSIO_NATIVE_NATIVE_RANDOM_ACCESS_FILE_HPP
12 :
13 : #include <boost/corosio/random_access_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_random_access_file_service.hpp>
20 : #endif
21 :
22 : #if BOOST_COROSIO_HAS_IO_URING
23 : #include <boost/corosio/native/detail/io_uring/io_uring_random_access_file.hpp>
24 : #endif
25 :
26 : #if BOOST_COROSIO_HAS_IOCP
27 : #include <boost/corosio/native/detail/iocp/win_random_access_file_service.hpp>
28 : #endif
29 : #endif // !BOOST_COROSIO_MRDOCS
30 :
31 : namespace boost::corosio {
32 :
33 : /** A random-access file with devirtualized async I/O operations.
34 :
35 : This class template inherits from @ref random_access_file and
36 : shadows `read_some_at` / `write_some_at` with versions that
37 : call the backend implementation directly, allowing the compiler
38 : to inline through the entire call chain.
39 :
40 : Non-async operations (`open`, `close`, `size`, `resize`,
41 : `sync_data`, `sync_all`) remain unchanged and dispatch through
42 : the compiled library.
43 :
44 : A `native_random_access_file` IS-A `random_access_file` and
45 : can be passed to any function expecting `random_access_file&`,
46 : in which 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 random_access_file.
60 :
61 : @par Example
62 : @code
63 : #include <boost/corosio/native/native_random_access_file.hpp>
64 :
65 : native_io_context<epoll> ctx;
66 : native_random_access_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_at(
70 : 0, capy::mutable_buffer(buf, sizeof(buf)));
71 : @endcode
72 :
73 : @see random_access_file, epoll_t, iocp_t
74 : */
75 : template<auto Backend>
76 : class native_random_access_file : public random_access_file
77 : {
78 : using backend_type = decltype(Backend);
79 : using impl_type = typename backend_type::random_access_file_type;
80 : using service_type =
81 : typename backend_type::random_access_file_service_type;
82 :
83 HIT 4 : impl_type& get_impl() noexcept
84 : {
85 4 : return *static_cast<impl_type*>(h_.get());
86 : }
87 :
88 : template<class MutableBufferSequence>
89 : struct native_read_at_awaitable
90 : {
91 : native_random_access_file& self_;
92 : std::uint64_t offset_;
93 : MutableBufferSequence buffers_;
94 : std::stop_token token_;
95 : mutable std::error_code ec_;
96 : mutable std::size_t bytes_transferred_ = 0;
97 :
98 2 : native_read_at_awaitable(
99 : native_random_access_file& self,
100 : std::uint64_t offset,
101 : MutableBufferSequence buffers) noexcept
102 2 : : self_(self)
103 2 : , offset_(offset)
104 2 : , buffers_(std::move(buffers))
105 : {
106 2 : }
107 :
108 2 : bool await_ready() const noexcept
109 : {
110 2 : return token_.stop_requested();
111 : }
112 :
113 2 : capy::io_result<std::size_t> await_resume() const noexcept
114 : {
115 2 : if (token_.stop_requested())
116 MIS 0 : return {make_error_code(std::errc::operation_canceled), 0};
117 HIT 2 : return {ec_, bytes_transferred_};
118 : }
119 :
120 2 : auto await_suspend(std::coroutine_handle<> h, capy::io_env const* env)
121 : -> std::coroutine_handle<>
122 : {
123 2 : token_ = env->stop_token;
124 6 : return self_.get_impl().read_some_at(
125 2 : offset_, h, env->executor, buffers_,
126 6 : token_, &ec_, &bytes_transferred_);
127 : }
128 : };
129 :
130 : template<class ConstBufferSequence>
131 : struct native_write_at_awaitable
132 : {
133 : native_random_access_file& self_;
134 : std::uint64_t offset_;
135 : ConstBufferSequence buffers_;
136 : std::stop_token token_;
137 : mutable std::error_code ec_;
138 : mutable std::size_t bytes_transferred_ = 0;
139 :
140 2 : native_write_at_awaitable(
141 : native_random_access_file& self,
142 : std::uint64_t offset,
143 : ConstBufferSequence buffers) noexcept
144 2 : : self_(self)
145 2 : , offset_(offset)
146 2 : , buffers_(std::move(buffers))
147 : {
148 2 : }
149 :
150 2 : bool await_ready() const noexcept
151 : {
152 2 : return token_.stop_requested();
153 : }
154 :
155 2 : capy::io_result<std::size_t> await_resume() const noexcept
156 : {
157 2 : if (token_.stop_requested())
158 MIS 0 : return {make_error_code(std::errc::operation_canceled), 0};
159 HIT 2 : return {ec_, bytes_transferred_};
160 : }
161 :
162 2 : auto await_suspend(std::coroutine_handle<> h, capy::io_env const* env)
163 : -> std::coroutine_handle<>
164 : {
165 2 : token_ = env->stop_token;
166 6 : return self_.get_impl().write_some_at(
167 2 : offset_, h, env->executor, buffers_,
168 6 : token_, &ec_, &bytes_transferred_);
169 : }
170 : };
171 :
172 : public:
173 : /** Construct a native random-access file from an execution context.
174 :
175 : @param ctx The execution context that will own this file.
176 : */
177 10 : explicit native_random_access_file(capy::execution_context& ctx)
178 10 : : random_access_file(create_handle<service_type>(ctx))
179 : {
180 10 : }
181 :
182 : /** Construct a native random-access file from an executor.
183 :
184 : @param ex The executor whose context will own this file.
185 : */
186 : template<class Ex>
187 : requires(!std::same_as<
188 : std::remove_cvref_t<Ex>,
189 : native_random_access_file>) &&
190 : capy::Executor<Ex>
191 : explicit native_random_access_file(Ex const& ex)
192 : : native_random_access_file(ex.context())
193 : {
194 : }
195 :
196 : /// Move construct.
197 : native_random_access_file(native_random_access_file&&) noexcept = default;
198 :
199 : /// Move assign.
200 : native_random_access_file&
201 : operator=(native_random_access_file&&) noexcept = default;
202 :
203 : native_random_access_file(native_random_access_file const&) = delete;
204 : native_random_access_file&
205 : operator=(native_random_access_file const&) = delete;
206 :
207 : /** Asynchronously read at the given offset.
208 :
209 : Calls the backend implementation directly, bypassing virtual
210 : dispatch. Otherwise identical to @ref random_access_file::read_some_at.
211 : */
212 : template<capy::MutableBufferSequence MB>
213 2 : auto read_some_at(std::uint64_t offset, MB const& buffers)
214 : {
215 2 : return native_read_at_awaitable<MB>(*this, offset, buffers);
216 : }
217 :
218 : /** Asynchronously write at the given offset.
219 :
220 : Calls the backend implementation directly, bypassing virtual
221 : dispatch. Otherwise identical to @ref random_access_file::write_some_at.
222 : */
223 : template<capy::ConstBufferSequence CB>
224 2 : auto write_some_at(std::uint64_t offset, CB const& buffers)
225 : {
226 2 : return native_write_at_awaitable<CB>(*this, offset, buffers);
227 : }
228 : };
229 :
230 : } // namespace boost::corosio
231 :
232 : #endif // BOOST_COROSIO_NATIVE_NATIVE_RANDOM_ACCESS_FILE_HPP
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