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_IO_IO_WRITE_STREAM_HPP
11 : #define BOOST_COROSIO_IO_IO_WRITE_STREAM_HPP
12 :
13 : #include <boost/corosio/detail/config.hpp>
14 : #include <boost/corosio/detail/op_base.hpp>
15 : #include <boost/corosio/io/io_object.hpp>
16 : #include <boost/corosio/detail/buffer_param.hpp>
17 : #include <boost/capy/io_result.hpp>
18 : #include <boost/capy/ex/executor_ref.hpp>
19 : #include <boost/capy/ex/io_env.hpp>
20 :
21 : #include <coroutine>
22 : #include <cstddef>
23 : #include <stop_token>
24 : #include <system_error>
25 :
26 : namespace boost::corosio {
27 :
28 : /** Writes bytes to a stream asynchronously.
29 :
30 : Provides the `write_some` operation via a pure virtual
31 : `do_write_some` dispatch point. Concrete classes override
32 : `do_write_some` to route through their implementation.
33 :
34 : Uses virtual inheritance from @ref io_object so that
35 : @ref io_stream can combine this with @ref io_read_stream
36 : without duplicating the `io_object` base.
37 :
38 : @par Thread Safety
39 : Distinct objects: Safe.
40 : Shared objects: Unsafe.
41 :
42 : @see io_read_stream, io_stream, io_object
43 : */
44 : class BOOST_COROSIO_DECL io_write_stream : virtual public io_object
45 : {
46 : protected:
47 : /// Awaitable for async write operations.
48 : template<class ConstBufferSequence>
49 : struct write_some_awaitable
50 : : detail::bytes_op_base<write_some_awaitable<ConstBufferSequence>>
51 : {
52 : private:
53 : friend io_write_stream;
54 :
55 HIT 204834 : write_some_awaitable(
56 : io_write_stream& ios, ConstBufferSequence buffers) noexcept
57 204834 : : ios_(ios)
58 204834 : , buffers_(std::move(buffers))
59 : {
60 204834 : }
61 :
62 : friend detail::bytes_op_base<write_some_awaitable<ConstBufferSequence>>;
63 : io_write_stream& ios_;
64 : ConstBufferSequence buffers_;
65 :
66 : std::coroutine_handle<>
67 204828 : dispatch(std::coroutine_handle<> h, capy::executor_ref ex) const
68 : {
69 409656 : return ios_.do_write_some(
70 614484 : h, ex, buffers_, this->token_, &this->ec_, &this->bytes_);
71 : }
72 : };
73 :
74 : /** Dispatch a write through the concrete implementation.
75 :
76 : @param h Coroutine handle to resume on completion.
77 : @param ex Executor for dispatching the completion.
78 : @param buffers Source buffer sequence.
79 : @param token Stop token for cancellation.
80 : @param ec Output error code.
81 : @param bytes Output bytes transferred.
82 :
83 : @return Coroutine handle to resume immediately.
84 : */
85 : virtual std::coroutine_handle<> do_write_some(
86 : std::coroutine_handle<> h,
87 : capy::executor_ref ex,
88 : buffer_param buffers,
89 : std::stop_token token,
90 : std::error_code* ec,
91 : std::size_t* bytes) = 0;
92 :
93 : /// Default construct; the handle is supplied through @ref io_object.
94 10651 : io_write_stream() noexcept = default;
95 :
96 : /// Move construct; the handle moves with @ref io_object.
97 : io_write_stream(io_write_stream&&) noexcept = default;
98 : /// Move assignment is disabled; reseating a live stream is not supported.
99 : io_write_stream& operator=(io_write_stream&&) noexcept = delete;
100 : /// Copy construction is disabled; the handle is uniquely owned.
101 : io_write_stream(io_write_stream const&) = delete;
102 : /// Copy assignment is disabled; the handle is uniquely owned.
103 : io_write_stream& operator=(io_write_stream const&) = delete;
104 :
105 : public:
106 : /** Asynchronously write data to the stream.
107 :
108 : Suspends the calling coroutine and initiates a kernel-level
109 : write. The coroutine resumes when at least one byte is written,
110 : an error occurs, or the operation is cancelled.
111 :
112 : This stream must outlive the returned awaitable. The memory
113 : referenced by @p buffers must remain valid until the operation
114 : completes.
115 :
116 : A closed stream completes with `errc::bad_file_descriptor`.
117 :
118 : @param buffers The buffer sequence containing data to write.
119 :
120 : @return An awaitable yielding `(error_code, std::size_t)`.
121 :
122 : @see io_stream::read_some
123 : */
124 : template<capy::ConstBufferSequence CB>
125 204834 : [[nodiscard]] auto write_some(CB const& buffers)
126 : {
127 204834 : return write_some_awaitable<CB>(*this, buffers);
128 : }
129 : };
130 :
131 : } // namespace boost::corosio
132 :
133 : #endif
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