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_READ_STREAM_HPP
11 : #define BOOST_COROSIO_IO_IO_READ_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 : /** Abstract base for streams that support async reads.
29 :
30 : Provides the `read_some` operation via a pure virtual
31 : `do_read_some` dispatch point. Concrete classes override
32 : `do_read_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_write_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_write_stream, io_stream, io_object
43 : */
44 : class BOOST_COROSIO_DECL io_read_stream : virtual public io_object
45 : {
46 : protected:
47 : /// Awaitable for async read operations.
48 : template<class MutableBufferSequence>
49 : struct read_some_awaitable
50 : : detail::bytes_op_base<read_some_awaitable<MutableBufferSequence>>
51 : {
52 : io_read_stream& ios_;
53 : MutableBufferSequence buffers_;
54 :
55 HIT 227926 : read_some_awaitable(
56 : io_read_stream& ios, MutableBufferSequence buffers) noexcept
57 227926 : : ios_(ios), buffers_(std::move(buffers)) {}
58 :
59 227926 : std::coroutine_handle<> dispatch(
60 : std::coroutine_handle<> h, capy::executor_ref ex) const
61 : {
62 455852 : return ios_.do_read_some(
63 683778 : h, ex, buffers_, this->token_, &this->ec_, &this->bytes_);
64 : }
65 : };
66 :
67 : /** Dispatch a read through the concrete implementation.
68 :
69 : @param h Coroutine handle to resume on completion.
70 : @param ex Executor for dispatching the completion.
71 : @param buffers Target buffer sequence.
72 : @param token Stop token for cancellation.
73 : @param ec Output error code.
74 : @param bytes Output bytes transferred.
75 :
76 : @return Coroutine handle to resume immediately.
77 : */
78 : virtual std::coroutine_handle<> do_read_some(
79 : std::coroutine_handle<>,
80 : capy::executor_ref,
81 : buffer_param,
82 : std::stop_token,
83 : std::error_code*,
84 : std::size_t*) = 0;
85 :
86 17076 : io_read_stream() noexcept = default;
87 :
88 : io_read_stream(io_read_stream&&) noexcept = default;
89 : io_read_stream& operator=(io_read_stream&&) noexcept = delete;
90 : io_read_stream(io_read_stream const&) = delete;
91 : io_read_stream& operator=(io_read_stream const&) = delete;
92 :
93 : public:
94 : /** Asynchronously read data from the stream.
95 :
96 : Suspends the calling coroutine and initiates a kernel-level
97 : read. The coroutine resumes when at least one byte is read,
98 : an error occurs, or the operation is cancelled.
99 :
100 : This stream must outlive the returned awaitable. The memory
101 : referenced by @p buffers must remain valid until the operation
102 : completes.
103 :
104 : @param buffers The buffer sequence to read data into.
105 :
106 : @return An awaitable yielding `(error_code, std::size_t)`.
107 :
108 : @see io_stream::write_some
109 : */
110 : template<capy::MutableBufferSequence MB>
111 227926 : auto read_some(MB const& buffers)
112 : {
113 227926 : return read_some_awaitable<MB>(*this, buffers);
114 : }
115 : };
116 :
117 : } // namespace boost::corosio
118 :
119 : #endif
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