TLA Line data Source code
1 : //
2 : // Copyright (c) 2026 Steve Gerbino
3 : // Copyright (c) 2026 Michael Vandeberg
4 : //
5 : // Distributed under the Boost Software License, Version 1.0. (See accompanying
6 : // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7 : //
8 : // Official repository: https://github.com/cppalliance/corosio
9 : //
10 :
11 : #ifndef BOOST_COROSIO_IO_IO_WRITE_STREAM_HPP
12 : #define BOOST_COROSIO_IO_IO_WRITE_STREAM_HPP
13 :
14 : #include <boost/corosio/detail/config.hpp>
15 : #include <boost/corosio/detail/op_base.hpp>
16 : #include <boost/corosio/io/io_object.hpp>
17 : #include <boost/corosio/detail/buffer_param.hpp>
18 : #include <boost/capy/results.hpp>
19 : #include <boost/capy/ex/executor_ref.hpp>
20 : #include <boost/capy/ex/await_context.hpp>
21 :
22 : #include <boost/capy/continuation.hpp>
23 :
24 : #include <coroutine>
25 : #include <cstddef>
26 : #include <stop_token>
27 : #include <system_error>
28 :
29 : namespace boost::corosio {
30 :
31 : /** Writes bytes to a stream asynchronously.
32 :
33 : Provides the `write_some` operation via a pure virtual
34 : `do_write_some` dispatch point. Concrete classes override
35 : `do_write_some` to route through their implementation.
36 :
37 : Uses virtual inheritance from @ref io_object so that
38 : @ref io_stream can combine this with @ref io_read_stream
39 : without duplicating the `io_object` base.
40 :
41 : @par Thread Safety
42 : Distinct objects: Safe.
43 : Shared objects: Unsafe.
44 :
45 : @see @ref io_read_stream, @ref io_stream, @ref io_object
46 : */
47 : class BOOST_COROSIO_DECL io_write_stream : virtual public io_object
48 : {
49 : protected:
50 : /// Awaitable for async write operations.
51 : template<class ConstBufferSequence>
52 : struct write_some_awaitable
53 : : detail::bytes_op_base<write_some_awaitable<ConstBufferSequence>>
54 : {
55 : private:
56 : friend io_write_stream;
57 :
58 HIT 233644 : write_some_awaitable(
59 : io_write_stream& ios, ConstBufferSequence buffers) noexcept
60 233644 : : ios_(ios)
61 233644 : , buffers_(std::move(buffers))
62 : {
63 233644 : }
64 :
65 : friend detail::bytes_op_base<write_some_awaitable<ConstBufferSequence>>;
66 : io_write_stream& ios_;
67 : ConstBufferSequence buffers_;
68 :
69 : std::coroutine_handle<>
70 233611 : dispatch(capy::continuation& cont, capy::executor_ref ex) const
71 : {
72 467222 : return ios_.do_write_some(
73 700833 : cont, ex, buffers_, this->token_, &this->ec_, &this->bytes_);
74 : }
75 : };
76 :
77 : /** Dispatch a write through the concrete implementation.
78 :
79 : @param cont Continuation to resume on completion; it lives in
80 : the awaiting frame until then.
81 : @param ex Executor for dispatching the completion.
82 : @param buffers Source buffer sequence.
83 : @param token Stop token for cancellation.
84 : @param ec Output error code.
85 : @param bytes Output bytes transferred.
86 :
87 : @return Coroutine handle to resume immediately.
88 : */
89 : virtual std::coroutine_handle<> do_write_some(
90 : capy::continuation& cont,
91 : capy::executor_ref ex,
92 : buffer_param buffers,
93 : std::stop_token token,
94 : std::error_code* ec,
95 : std::size_t* bytes) = 0;
96 :
97 : /// Default construct; the handle is supplied through @ref io_object.
98 25997 : io_write_stream() noexcept = default;
99 :
100 : /// Move construct; the handle moves with @ref io_object.
101 : io_write_stream(io_write_stream&&) noexcept = default;
102 : /// Move assignment is disabled; reseating a live stream is not supported.
103 : io_write_stream& operator=(io_write_stream&&) noexcept = delete;
104 : /// Copy construction is disabled; the handle is uniquely owned.
105 : io_write_stream(io_write_stream const&) = delete;
106 : /// Copy assignment is disabled; the handle is uniquely owned.
107 : io_write_stream& operator=(io_write_stream const&) = delete;
108 :
109 : public:
110 : /** Asynchronously write data to the stream.
111 :
112 : Suspends the calling coroutine and initiates a kernel-level
113 : write. The coroutine resumes when at least one byte is written,
114 : an error occurs, or the operation is cancelled.
115 :
116 : This stream must outlive the returned awaitable. The memory
117 : referenced by @p buffers must remain valid until the operation
118 : completes.
119 :
120 : A closed stream completes with `errc::bad_file_descriptor`.
121 :
122 : @param buffers The buffer sequence containing data to write.
123 :
124 : @return An awaitable yielding `(error_code, std::size_t)`.
125 :
126 : @see @ref io_stream::read_some
127 : */
128 : template<capy::ConstBufferSequence CB>
129 233644 : [[nodiscard]] auto write_some(CB const& buffers)
130 : {
131 233644 : return write_some_awaitable<CB>(*this, buffers);
132 : }
133 : };
134 :
135 : } // namespace boost::corosio
136 :
137 : #endif
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