. /include/boost/corosio /io /io_read_stream.hpp
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1   // 1   //
2   // Copyright (c) 2026 Steve Gerbino 2   // Copyright (c) 2026 Steve Gerbino
  3 + // Copyright (c) 2026 Michael Vandeberg
3   // 4   //
4   // Distributed under the Boost Software License, Version 1.0. (See accompanying 5   // 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   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6   // 7   //
7   // Official repository: https://github.com/cppalliance/corosio 8   // Official repository: https://github.com/cppalliance/corosio
8   // 9   //
9   10  
10   #ifndef BOOST_COROSIO_IO_IO_READ_STREAM_HPP 11   #ifndef BOOST_COROSIO_IO_IO_READ_STREAM_HPP
11   #define BOOST_COROSIO_IO_IO_READ_STREAM_HPP 12   #define BOOST_COROSIO_IO_IO_READ_STREAM_HPP
12   13  
13   #include <boost/corosio/detail/config.hpp> 14   #include <boost/corosio/detail/config.hpp>
14   #include <boost/corosio/detail/op_base.hpp> 15   #include <boost/corosio/detail/op_base.hpp>
15   #include <boost/corosio/io/io_object.hpp> 16   #include <boost/corosio/io/io_object.hpp>
16   #include <boost/corosio/detail/buffer_param.hpp> 17   #include <boost/corosio/detail/buffer_param.hpp>
17   #include <boost/capy/results.hpp> 18   #include <boost/capy/results.hpp>
18   #include <boost/capy/ex/executor_ref.hpp> 19   #include <boost/capy/ex/executor_ref.hpp>
19   #include <boost/capy/ex/await_context.hpp> 20   #include <boost/capy/ex/await_context.hpp>
20   21  
21   #include <boost/capy/continuation.hpp> 22   #include <boost/capy/continuation.hpp>
22   23  
23   #include <coroutine> 24   #include <coroutine>
24   #include <cstddef> 25   #include <cstddef>
25   #include <stop_token> 26   #include <stop_token>
26   #include <system_error> 27   #include <system_error>
27   28  
28   namespace boost::corosio { 29   namespace boost::corosio {
29   30  
30   /** Reads bytes from a stream asynchronously. 31   /** Reads bytes from a stream asynchronously.
31   32  
32   Provides the `read_some` operation via a pure virtual 33   Provides the `read_some` operation via a pure virtual
33   `do_read_some` dispatch point. Concrete classes override 34   `do_read_some` dispatch point. Concrete classes override
34   `do_read_some` to route through their implementation. 35   `do_read_some` to route through their implementation.
35   36  
36   Uses virtual inheritance from @ref io_object so that 37   Uses virtual inheritance from @ref io_object so that
37   @ref io_stream can combine this with @ref io_write_stream 38   @ref io_stream can combine this with @ref io_write_stream
38   without duplicating the `io_object` base. 39   without duplicating the `io_object` base.
39   40  
40   @par Thread Safety 41   @par Thread Safety
41   Distinct objects: Safe. 42   Distinct objects: Safe.
42   Shared objects: Unsafe. 43   Shared objects: Unsafe.
43   44  
44 - @see io_write_stream, io_stream, io_object 45 + @see @ref io_write_stream, @ref io_stream, @ref io_object
45   */ 46   */
46   class BOOST_COROSIO_DECL io_read_stream : virtual public io_object 47   class BOOST_COROSIO_DECL io_read_stream : virtual public io_object
47   { 48   {
48   protected: 49   protected:
49   /// Awaitable for async read operations. 50   /// Awaitable for async read operations.
50   template<class MutableBufferSequence> 51   template<class MutableBufferSequence>
51   struct read_some_awaitable 52   struct read_some_awaitable
52   : detail::bytes_op_base<read_some_awaitable<MutableBufferSequence>> 53   : detail::bytes_op_base<read_some_awaitable<MutableBufferSequence>>
53   { 54   {
54   private: 55   private:
55   friend io_read_stream; 56   friend io_read_stream;
56   57  
HITCBC 57   207047 read_some_awaitable( 58   235386 read_some_awaitable(
58   io_read_stream& ios, MutableBufferSequence buffers) noexcept 59   io_read_stream& ios, MutableBufferSequence buffers) noexcept
HITCBC 59   207047 : ios_(ios) 60   235386 : ios_(ios)
HITCBC 60   207047 , buffers_(std::move(buffers)) 61   235386 , buffers_(std::move(buffers))
61   { 62   {
HITCBC 62   207047 } 63   235386 }
63   64  
64   friend detail::bytes_op_base< 65   friend detail::bytes_op_base<
65   read_some_awaitable<MutableBufferSequence>>; 66   read_some_awaitable<MutableBufferSequence>>;
66   io_read_stream& ios_; 67   io_read_stream& ios_;
67   MutableBufferSequence buffers_; 68   MutableBufferSequence buffers_;
68   69  
69   std::coroutine_handle<> 70   std::coroutine_handle<>
HITCBC 70   207024 dispatch(capy::continuation& cont, capy::executor_ref ex) const 71   235359 dispatch(capy::continuation& cont, capy::executor_ref ex) const
71   { 72   {
HITCBC 72   414048 return ios_.do_read_some( 73   470718 return ios_.do_read_some(
HITCBC 73   621072 cont, ex, buffers_, this->token_, &this->ec_, &this->bytes_); 74   706077 cont, ex, buffers_, this->token_, &this->ec_, &this->bytes_);
74   } 75   }
75   }; 76   };
76   77  
77   /** Dispatch a read through the concrete implementation. 78   /** Dispatch a read through the concrete implementation.
78   79  
79   @param cont Continuation to resume on completion; it lives in 80   @param cont Continuation to resume on completion; it lives in
80   the awaiting frame until then. 81   the awaiting frame until then.
81   @param ex Executor for dispatching the completion. 82   @param ex Executor for dispatching the completion.
82   @param buffers Target buffer sequence. 83   @param buffers Target buffer sequence.
83   @param token Stop token for cancellation. 84   @param token Stop token for cancellation.
84   @param ec Output error code. 85   @param ec Output error code.
85   @param bytes Output bytes transferred. 86   @param bytes Output bytes transferred.
86   87  
87   @return Coroutine handle to resume immediately. 88   @return Coroutine handle to resume immediately.
88   */ 89   */
89   virtual std::coroutine_handle<> do_read_some( 90   virtual std::coroutine_handle<> do_read_some(
90   capy::continuation& cont, 91   capy::continuation& cont,
91   capy::executor_ref ex, 92   capy::executor_ref ex,
92   buffer_param buffers, 93   buffer_param buffers,
93   std::stop_token token, 94   std::stop_token token,
94   std::error_code* ec, 95   std::error_code* ec,
95   std::size_t* bytes) = 0; 96   std::size_t* bytes) = 0;
96   97  
97   /// Default construct; the handle is supplied through @ref io_object. 98   /// Default construct; the handle is supplied through @ref io_object.
HITCBC 98   26077 io_read_stream() noexcept = default; 99   25997 io_read_stream() noexcept = default;
99   100  
100   /// Move construct; the handle moves with @ref io_object. 101   /// Move construct; the handle moves with @ref io_object.
101   io_read_stream(io_read_stream&&) noexcept = default; 102   io_read_stream(io_read_stream&&) noexcept = default;
102   /// Move assignment is disabled; reseating a live stream is not supported. 103   /// Move assignment is disabled; reseating a live stream is not supported.
103   io_read_stream& operator=(io_read_stream&&) noexcept = delete; 104   io_read_stream& operator=(io_read_stream&&) noexcept = delete;
104   /// Copy construction is disabled; the handle is uniquely owned. 105   /// Copy construction is disabled; the handle is uniquely owned.
105   io_read_stream(io_read_stream const&) = delete; 106   io_read_stream(io_read_stream const&) = delete;
106   /// Copy assignment is disabled; the handle is uniquely owned. 107   /// Copy assignment is disabled; the handle is uniquely owned.
107   io_read_stream& operator=(io_read_stream const&) = delete; 108   io_read_stream& operator=(io_read_stream const&) = delete;
108   109  
109   public: 110   public:
110   /** Asynchronously read data from the stream. 111   /** Asynchronously read data from the stream.
111   112  
112   Suspends the calling coroutine and initiates a kernel-level 113   Suspends the calling coroutine and initiates a kernel-level
113   read. The coroutine resumes when at least one byte is read, 114   read. The coroutine resumes when at least one byte is read,
114   an error occurs, or the operation is cancelled. 115   an error occurs, or the operation is cancelled.
115   116  
116   This stream must outlive the returned awaitable. The memory 117   This stream must outlive the returned awaitable. The memory
117   referenced by @p buffers must remain valid until the operation 118   referenced by @p buffers must remain valid until the operation
118   completes. 119   completes.
119   120  
120   A closed stream completes with `errc::bad_file_descriptor`. 121   A closed stream completes with `errc::bad_file_descriptor`.
121   122  
122   @param buffers The buffer sequence to read data into. 123   @param buffers The buffer sequence to read data into.
123   124  
124   @return An awaitable yielding `(error_code, std::size_t)`. 125   @return An awaitable yielding `(error_code, std::size_t)`.
125   126  
126 - @see io_stream::write_some 127 + @see @ref io_stream::write_some
127   */ 128   */
128   template<capy::MutableBufferSequence MB> 129   template<capy::MutableBufferSequence MB>
HITCBC 129   207047 [[nodiscard]] auto read_some(MB const& buffers) 130   235386 [[nodiscard]] auto read_some(MB const& buffers)
130   { 131   {
HITCBC 131   207047 return read_some_awaitable<MB>(*this, buffers); 132   235386 return read_some_awaitable<MB>(*this, buffers);
132   } 133   }
133   }; 134   };
134   135  
135   } // namespace boost::corosio 136   } // namespace boost::corosio
136   137  
137   #endif 138   #endif