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//
1  
//
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// Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
2  
// Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
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// Copyright (c) 2026 Steve Gerbino
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// Copyright (c) 2026 Steve Gerbino
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//
4  
//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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)
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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//
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// Official repository: https://github.com/cppalliance/corosio
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// Official repository: https://github.com/cppalliance/corosio
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//
9  
//
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10  

11  
#ifndef BOOST_COROSIO_TCP_SOCKET_HPP
11  
#ifndef BOOST_COROSIO_TCP_SOCKET_HPP
12  
#define BOOST_COROSIO_TCP_SOCKET_HPP
12  
#define BOOST_COROSIO_TCP_SOCKET_HPP
13  

13  

14  
#include <boost/corosio/detail/config.hpp>
14  
#include <boost/corosio/detail/config.hpp>
15  
#include <boost/corosio/detail/platform.hpp>
15  
#include <boost/corosio/detail/platform.hpp>
16  
#include <boost/corosio/detail/except.hpp>
16  
#include <boost/corosio/detail/except.hpp>
17  
#include <boost/corosio/detail/native_handle.hpp>
17  
#include <boost/corosio/detail/native_handle.hpp>
18  
#include <boost/corosio/detail/op_base.hpp>
18  
#include <boost/corosio/detail/op_base.hpp>
19  
#include <boost/corosio/io/io_stream.hpp>
19  
#include <boost/corosio/io/io_stream.hpp>
20  
#include <boost/capy/io_result.hpp>
20  
#include <boost/capy/io_result.hpp>
21  
#include <boost/corosio/detail/buffer_param.hpp>
21  
#include <boost/corosio/detail/buffer_param.hpp>
22  
#include <boost/corosio/endpoint.hpp>
22  
#include <boost/corosio/endpoint.hpp>
23  
#include <boost/corosio/shutdown_type.hpp>
23  
#include <boost/corosio/shutdown_type.hpp>
24  
#include <boost/corosio/tcp.hpp>
24  
#include <boost/corosio/tcp.hpp>
25  
#include <boost/capy/ex/executor_ref.hpp>
25  
#include <boost/capy/ex/executor_ref.hpp>
26  
#include <boost/capy/ex/execution_context.hpp>
26  
#include <boost/capy/ex/execution_context.hpp>
27  
#include <boost/capy/ex/io_env.hpp>
27  
#include <boost/capy/ex/io_env.hpp>
28  
#include <boost/capy/concept/executor.hpp>
28  
#include <boost/capy/concept/executor.hpp>
29  

29  

30  
#include <system_error>
30  
#include <system_error>
31  

31  

32  
#include <concepts>
32  
#include <concepts>
33  
#include <coroutine>
33  
#include <coroutine>
34  
#include <cstddef>
34  
#include <cstddef>
35  
#include <stop_token>
35  
#include <stop_token>
36  
#include <type_traits>
36  
#include <type_traits>
37  

37  

38  
namespace boost::corosio {
38  
namespace boost::corosio {
39  

39  

40  
/** An asynchronous TCP socket for coroutine I/O.
40  
/** An asynchronous TCP socket for coroutine I/O.
41  

41  

42  
    This class provides asynchronous TCP socket operations that return
42  
    This class provides asynchronous TCP socket operations that return
43  
    awaitable types. Each operation participates in the affine awaitable
43  
    awaitable types. Each operation participates in the affine awaitable
44  
    protocol, ensuring coroutines resume on the correct executor.
44  
    protocol, ensuring coroutines resume on the correct executor.
45  

45  

46  
    The socket must be opened before performing I/O operations. Operations
46  
    The socket must be opened before performing I/O operations. Operations
47  
    support cancellation through `std::stop_token` via the affine protocol,
47  
    support cancellation through `std::stop_token` via the affine protocol,
48  
    or explicitly through the `cancel()` member function.
48  
    or explicitly through the `cancel()` member function.
49  

49  

50  
    @par Thread Safety
50  
    @par Thread Safety
51  
    Distinct objects: Safe.@n
51  
    Distinct objects: Safe.@n
52  
    Shared objects: Unsafe. A socket must not have concurrent operations
52  
    Shared objects: Unsafe. A socket must not have concurrent operations
53  
    of the same type (e.g., two simultaneous reads). One read and one
53  
    of the same type (e.g., two simultaneous reads). One read and one
54  
    write may be in flight simultaneously.
54  
    write may be in flight simultaneously.
55  

55  

56  
    @par Semantics
56  
    @par Semantics
57  
    Wraps the platform TCP/IP stack. Operations dispatch to
57  
    Wraps the platform TCP/IP stack. Operations dispatch to
58  
    OS socket APIs via the io_context reactor (epoll, IOCP,
58  
    OS socket APIs via the io_context reactor (epoll, IOCP,
59  
    kqueue). Satisfies @ref capy::Stream.
59  
    kqueue). Satisfies @ref capy::Stream.
60  

60  

61  
    @par Example
61  
    @par Example
62  
    @code
62  
    @code
63  
    io_context ioc;
63  
    io_context ioc;
64  
    tcp_socket s(ioc);
64  
    tcp_socket s(ioc);
65  
    s.open();
65  
    s.open();
66  

66  

67  
    // Using structured bindings
67  
    // Using structured bindings
68  
    auto [ec] = co_await s.connect(
68  
    auto [ec] = co_await s.connect(
69  
        endpoint(ipv4_address::loopback(), 8080));
69  
        endpoint(ipv4_address::loopback(), 8080));
70  
    if (ec)
70  
    if (ec)
71  
        co_return;
71  
        co_return;
72  

72  

73  
    char buf[1024];
73  
    char buf[1024];
74  
    auto [read_ec, n] = co_await s.read_some(
74  
    auto [read_ec, n] = co_await s.read_some(
75  
        capy::mutable_buffer(buf, sizeof(buf)));
75  
        capy::mutable_buffer(buf, sizeof(buf)));
76  
    @endcode
76  
    @endcode
77  
*/
77  
*/
78  
class BOOST_COROSIO_DECL tcp_socket : public io_stream
78  
class BOOST_COROSIO_DECL tcp_socket : public io_stream
79  
{
79  
{
80  
public:
80  
public:
81  
    using shutdown_type = corosio::shutdown_type;
81  
    using shutdown_type = corosio::shutdown_type;
82  
    using enum corosio::shutdown_type;
82  
    using enum corosio::shutdown_type;
83  

83  

84  
    /** Define backend hooks for TCP socket operations.
84  
    /** Define backend hooks for TCP socket operations.
85  

85  

86  
        Platform backends (epoll, IOCP, kqueue, select) derive from
86  
        Platform backends (epoll, IOCP, kqueue, select) derive from
87  
        this to implement socket I/O, connection, and option management.
87  
        this to implement socket I/O, connection, and option management.
88  
    */
88  
    */
89  
    struct implementation : io_stream::implementation
89  
    struct implementation : io_stream::implementation
90  
    {
90  
    {
91  
        /** Initiate an asynchronous connect to the given endpoint.
91  
        /** Initiate an asynchronous connect to the given endpoint.
92  

92  

93  
            @param h Coroutine handle to resume on completion.
93  
            @param h Coroutine handle to resume on completion.
94  
            @param ex Executor for dispatching the completion.
94  
            @param ex Executor for dispatching the completion.
95  
            @param ep The remote endpoint to connect to.
95  
            @param ep The remote endpoint to connect to.
96  
            @param token Stop token for cancellation.
96  
            @param token Stop token for cancellation.
97  
            @param ec Output error code.
97  
            @param ec Output error code.
98  

98  

99  
            @return Coroutine handle to resume immediately.
99  
            @return Coroutine handle to resume immediately.
100  
        */
100  
        */
101  
        virtual std::coroutine_handle<> connect(
101  
        virtual std::coroutine_handle<> connect(
102  
            std::coroutine_handle<> h,
102  
            std::coroutine_handle<> h,
103  
            capy::executor_ref ex,
103  
            capy::executor_ref ex,
104  
            endpoint ep,
104  
            endpoint ep,
105  
            std::stop_token token,
105  
            std::stop_token token,
106  
            std::error_code* ec) = 0;
106  
            std::error_code* ec) = 0;
107  

107  

108  
        /** Shut down the socket for the given direction(s).
108  
        /** Shut down the socket for the given direction(s).
109  

109  

110  
            @param what The shutdown direction.
110  
            @param what The shutdown direction.
111  

111  

112  
            @return Error code on failure, empty on success.
112  
            @return Error code on failure, empty on success.
113  
        */
113  
        */
114  
        virtual std::error_code shutdown(shutdown_type what) noexcept = 0;
114  
        virtual std::error_code shutdown(shutdown_type what) noexcept = 0;
115  

115  

116  
        /// Return the platform socket descriptor.
116  
        /// Return the platform socket descriptor.
117  
        virtual native_handle_type native_handle() const noexcept = 0;
117  
        virtual native_handle_type native_handle() const noexcept = 0;
118  

118  

119  
        /** Request cancellation of pending asynchronous operations.
119  
        /** Request cancellation of pending asynchronous operations.
120  

120  

121  
            All outstanding operations complete with operation_canceled error.
121  
            All outstanding operations complete with operation_canceled error.
122  
            Check `ec == cond::canceled` for portable comparison.
122  
            Check `ec == cond::canceled` for portable comparison.
123  
        */
123  
        */
124  
        virtual void cancel() noexcept = 0;
124  
        virtual void cancel() noexcept = 0;
125  

125  

126  
        /** Set a socket option.
126  
        /** Set a socket option.
127  

127  

128  
            @param level The protocol level (e.g. `SOL_SOCKET`).
128  
            @param level The protocol level (e.g. `SOL_SOCKET`).
129  
            @param optname The option name (e.g. `SO_KEEPALIVE`).
129  
            @param optname The option name (e.g. `SO_KEEPALIVE`).
130  
            @param data Pointer to the option value.
130  
            @param data Pointer to the option value.
131  
            @param size Size of the option value in bytes.
131  
            @param size Size of the option value in bytes.
132  
            @return Error code on failure, empty on success.
132  
            @return Error code on failure, empty on success.
133  
        */
133  
        */
134  
        virtual std::error_code set_option(
134  
        virtual std::error_code set_option(
135  
            int level,
135  
            int level,
136  
            int optname,
136  
            int optname,
137  
            void const* data,
137  
            void const* data,
138  
            std::size_t size) noexcept = 0;
138  
            std::size_t size) noexcept = 0;
139  

139  

140  
        /** Get a socket option.
140  
        /** Get a socket option.
141  

141  

142  
            @param level The protocol level (e.g. `SOL_SOCKET`).
142  
            @param level The protocol level (e.g. `SOL_SOCKET`).
143  
            @param optname The option name (e.g. `SO_KEEPALIVE`).
143  
            @param optname The option name (e.g. `SO_KEEPALIVE`).
144  
            @param data Pointer to receive the option value.
144  
            @param data Pointer to receive the option value.
145  
            @param size On entry, the size of the buffer. On exit,
145  
            @param size On entry, the size of the buffer. On exit,
146  
                the size of the option value.
146  
                the size of the option value.
147  
            @return Error code on failure, empty on success.
147  
            @return Error code on failure, empty on success.
148  
        */
148  
        */
149  
        virtual std::error_code
149  
        virtual std::error_code
150  
        get_option(int level, int optname, void* data, std::size_t* size)
150  
        get_option(int level, int optname, void* data, std::size_t* size)
151  
            const noexcept = 0;
151  
            const noexcept = 0;
152  

152  

153  
        /// Return the cached local endpoint.
153  
        /// Return the cached local endpoint.
154  
        virtual endpoint local_endpoint() const noexcept = 0;
154  
        virtual endpoint local_endpoint() const noexcept = 0;
155  

155  

156  
        /// Return the cached remote endpoint.
156  
        /// Return the cached remote endpoint.
157  
        virtual endpoint remote_endpoint() const noexcept = 0;
157  
        virtual endpoint remote_endpoint() const noexcept = 0;
158  
    };
158  
    };
159  

159  

160  
    /// Represent the awaitable returned by @ref connect.
160  
    /// Represent the awaitable returned by @ref connect.
161  
    struct connect_awaitable
161  
    struct connect_awaitable
162  
        : detail::void_op_base<connect_awaitable>
162  
        : detail::void_op_base<connect_awaitable>
163  
    {
163  
    {
164  
        tcp_socket& s_;
164  
        tcp_socket& s_;
165  
        endpoint endpoint_;
165  
        endpoint endpoint_;
166  

166  

167  
        connect_awaitable(tcp_socket& s, endpoint ep) noexcept
167  
        connect_awaitable(tcp_socket& s, endpoint ep) noexcept
168  
            : s_(s), endpoint_(ep) {}
168  
            : s_(s), endpoint_(ep) {}
169  

169  

170  
        std::coroutine_handle<> dispatch(
170  
        std::coroutine_handle<> dispatch(
171  
            std::coroutine_handle<> h, capy::executor_ref ex) const
171  
            std::coroutine_handle<> h, capy::executor_ref ex) const
172  
        {
172  
        {
173  
            return s_.get().connect(h, ex, endpoint_, token_, &ec_);
173  
            return s_.get().connect(h, ex, endpoint_, token_, &ec_);
174  
        }
174  
        }
175  
    };
175  
    };
176  

176  

177  
public:
177  
public:
178  
    /** Destructor.
178  
    /** Destructor.
179  

179  

180  
        Closes the socket if open, cancelling any pending operations.
180  
        Closes the socket if open, cancelling any pending operations.
181  
    */
181  
    */
182  
    ~tcp_socket() override;
182  
    ~tcp_socket() override;
183  

183  

184  
    /** Construct a socket from an execution context.
184  
    /** Construct a socket from an execution context.
185  

185  

186  
        @param ctx The execution context that will own this socket.
186  
        @param ctx The execution context that will own this socket.
187  
    */
187  
    */
188  
    explicit tcp_socket(capy::execution_context& ctx);
188  
    explicit tcp_socket(capy::execution_context& ctx);
189  

189  

190  
    /** Construct a socket from an executor.
190  
    /** Construct a socket from an executor.
191  

191  

192  
        The socket is associated with the executor's context.
192  
        The socket is associated with the executor's context.
193  

193  

194  
        @param ex The executor whose context will own the socket.
194  
        @param ex The executor whose context will own the socket.
195  
    */
195  
    */
196  
    template<class Ex>
196  
    template<class Ex>
197  
        requires(!std::same_as<std::remove_cvref_t<Ex>, tcp_socket>) &&
197  
        requires(!std::same_as<std::remove_cvref_t<Ex>, tcp_socket>) &&
198  
        capy::Executor<Ex>
198  
        capy::Executor<Ex>
199  
    explicit tcp_socket(Ex const& ex) : tcp_socket(ex.context())
199  
    explicit tcp_socket(Ex const& ex) : tcp_socket(ex.context())
200  
    {
200  
    {
201  
    }
201  
    }
202  

202  

203  
    /** Move constructor.
203  
    /** Move constructor.
204  

204  

205  
        Transfers ownership of the socket resources.
205  
        Transfers ownership of the socket resources.
206  

206  

207  
        @param other The socket to move from.
207  
        @param other The socket to move from.
208  

208  

209  
        @pre No awaitables returned by @p other's methods exist.
209  
        @pre No awaitables returned by @p other's methods exist.
210  
        @pre @p other is not referenced as a peer in any outstanding
210  
        @pre @p other is not referenced as a peer in any outstanding
211  
            accept awaitable.
211  
            accept awaitable.
212  
        @pre The execution context associated with @p other must
212  
        @pre The execution context associated with @p other must
213  
            outlive this socket.
213  
            outlive this socket.
214  
    */
214  
    */
215  
    tcp_socket(tcp_socket&& other) noexcept : io_object(std::move(other)) {}
215  
    tcp_socket(tcp_socket&& other) noexcept : io_object(std::move(other)) {}
216  

216  

217  
    /** Move assignment operator.
217  
    /** Move assignment operator.
218  

218  

219  
        Closes any existing socket and transfers ownership.
219  
        Closes any existing socket and transfers ownership.
220  

220  

221  
        @param other The socket to move from.
221  
        @param other The socket to move from.
222  

222  

223  
        @pre No awaitables returned by either `*this` or @p other's
223  
        @pre No awaitables returned by either `*this` or @p other's
224  
            methods exist.
224  
            methods exist.
225  
        @pre Neither `*this` nor @p other is referenced as a peer in
225  
        @pre Neither `*this` nor @p other is referenced as a peer in
226  
            any outstanding accept awaitable.
226  
            any outstanding accept awaitable.
227  
        @pre The execution context associated with @p other must
227  
        @pre The execution context associated with @p other must
228  
            outlive this socket.
228  
            outlive this socket.
229  

229  

230  
        @return Reference to this socket.
230  
        @return Reference to this socket.
231  
    */
231  
    */
232  
    tcp_socket& operator=(tcp_socket&& other) noexcept
232  
    tcp_socket& operator=(tcp_socket&& other) noexcept
233  
    {
233  
    {
234  
        if (this != &other)
234  
        if (this != &other)
235  
        {
235  
        {
236  
            close();
236  
            close();
237  
            h_ = std::move(other.h_);
237  
            h_ = std::move(other.h_);
238  
        }
238  
        }
239  
        return *this;
239  
        return *this;
240  
    }
240  
    }
241  

241  

242  
    tcp_socket(tcp_socket const&)            = delete;
242  
    tcp_socket(tcp_socket const&)            = delete;
243  
    tcp_socket& operator=(tcp_socket const&) = delete;
243  
    tcp_socket& operator=(tcp_socket const&) = delete;
244  

244  

245  
    /** Open the socket.
245  
    /** Open the socket.
246  

246  

247  
        Creates a TCP socket and associates it with the platform
247  
        Creates a TCP socket and associates it with the platform
248  
        reactor (IOCP on Windows). Calling @ref connect on a closed
248  
        reactor (IOCP on Windows). Calling @ref connect on a closed
249  
        socket opens it automatically with the endpoint's address family,
249  
        socket opens it automatically with the endpoint's address family,
250  
        so explicit `open()` is only needed when socket options must be
250  
        so explicit `open()` is only needed when socket options must be
251  
        set before connecting.
251  
        set before connecting.
252  

252  

253  
        @param proto The protocol (IPv4 or IPv6). Defaults to
253  
        @param proto The protocol (IPv4 or IPv6). Defaults to
254  
            `tcp::v4()`.
254  
            `tcp::v4()`.
255  

255  

256  
        @throws std::system_error on failure.
256  
        @throws std::system_error on failure.
257  
    */
257  
    */
258  
    void open(tcp proto = tcp::v4());
258  
    void open(tcp proto = tcp::v4());
259  

259  

260  
    /** Bind the socket to a local endpoint.
260  
    /** Bind the socket to a local endpoint.
261  

261  

262  
        Associates the socket with a local address and port before
262  
        Associates the socket with a local address and port before
263  
        connecting. Useful for multi-homed hosts or source-port
263  
        connecting. Useful for multi-homed hosts or source-port
264  
        pinning.
264  
        pinning.
265  

265  

266  
        @param ep The local endpoint to bind to.
266  
        @param ep The local endpoint to bind to.
267  

267  

268  
        @return An error code indicating success or the reason for
268  
        @return An error code indicating success or the reason for
269  
            failure.
269  
            failure.
270  

270  

271  
        @par Error Conditions
271  
        @par Error Conditions
272  
        @li `errc::address_in_use`: The endpoint is already in use.
272  
        @li `errc::address_in_use`: The endpoint is already in use.
273  
        @li `errc::address_not_available`: The address is not
273  
        @li `errc::address_not_available`: The address is not
274  
            available on any local interface.
274  
            available on any local interface.
275  
        @li `errc::permission_denied`: Insufficient privileges to
275  
        @li `errc::permission_denied`: Insufficient privileges to
276  
            bind to the endpoint (e.g., privileged port).
276  
            bind to the endpoint (e.g., privileged port).
277  

277  

278  
        @throws std::logic_error if the socket is not open.
278  
        @throws std::logic_error if the socket is not open.
279  
    */
279  
    */
280  
    [[nodiscard]] std::error_code bind(endpoint ep);
280  
    [[nodiscard]] std::error_code bind(endpoint ep);
281  

281  

282  
    /** Close the socket.
282  
    /** Close the socket.
283  

283  

284  
        Releases socket resources. Any pending operations complete
284  
        Releases socket resources. Any pending operations complete
285  
        with `errc::operation_canceled`.
285  
        with `errc::operation_canceled`.
286  
    */
286  
    */
287  
    void close();
287  
    void close();
288  

288  

289  
    /** Check if the socket is open.
289  
    /** Check if the socket is open.
290  

290  

291  
        @return `true` if the socket is open and ready for operations.
291  
        @return `true` if the socket is open and ready for operations.
292  
    */
292  
    */
293  
    bool is_open() const noexcept
293  
    bool is_open() const noexcept
294  
    {
294  
    {
295  
#if BOOST_COROSIO_HAS_IOCP && !defined(BOOST_COROSIO_MRDOCS)
295  
#if BOOST_COROSIO_HAS_IOCP && !defined(BOOST_COROSIO_MRDOCS)
296  
        return h_ && get().native_handle() != ~native_handle_type(0);
296  
        return h_ && get().native_handle() != ~native_handle_type(0);
297  
#else
297  
#else
298  
        return h_ && get().native_handle() >= 0;
298  
        return h_ && get().native_handle() >= 0;
299  
#endif
299  
#endif
300  
    }
300  
    }
301  

301  

302  
    /** Initiate an asynchronous connect operation.
302  
    /** Initiate an asynchronous connect operation.
303  

303  

304  
        If the socket is not already open, it is opened automatically
304  
        If the socket is not already open, it is opened automatically
305  
        using the address family of @p ep (IPv4 or IPv6). If the socket
305  
        using the address family of @p ep (IPv4 or IPv6). If the socket
306  
        is already open, the existing file descriptor is used as-is.
306  
        is already open, the existing file descriptor is used as-is.
307  

307  

308  
        The operation supports cancellation via `std::stop_token` through
308  
        The operation supports cancellation via `std::stop_token` through
309  
        the affine awaitable protocol. If the associated stop token is
309  
        the affine awaitable protocol. If the associated stop token is
310  
        triggered, the operation completes immediately with
310  
        triggered, the operation completes immediately with
311  
        `errc::operation_canceled`.
311  
        `errc::operation_canceled`.
312  

312  

313  
        @param ep The remote endpoint to connect to.
313  
        @param ep The remote endpoint to connect to.
314  

314  

315  
        @return An awaitable that completes with `io_result<>`.
315  
        @return An awaitable that completes with `io_result<>`.
316  
            Returns success (default error_code) on successful connection,
316  
            Returns success (default error_code) on successful connection,
317  
            or an error code on failure including:
317  
            or an error code on failure including:
318  
            - connection_refused: No server listening at endpoint
318  
            - connection_refused: No server listening at endpoint
319  
            - timed_out: Connection attempt timed out
319  
            - timed_out: Connection attempt timed out
320  
            - network_unreachable: No route to host
320  
            - network_unreachable: No route to host
321  
            - operation_canceled: Cancelled via stop_token or cancel().
321  
            - operation_canceled: Cancelled via stop_token or cancel().
322  
                Check `ec == cond::canceled` for portable comparison.
322  
                Check `ec == cond::canceled` for portable comparison.
323  

323  

324  
        @throws std::system_error if the socket needs to be opened
324  
        @throws std::system_error if the socket needs to be opened
325  
            and the open fails.
325  
            and the open fails.
326  

326  

327  
        @par Preconditions
327  
        @par Preconditions
328  
        This socket must outlive the returned awaitable.
328  
        This socket must outlive the returned awaitable.
329  

329  

330  
        @par Example
330  
        @par Example
331  
        @code
331  
        @code
332  
        // Socket opened automatically with correct address family:
332  
        // Socket opened automatically with correct address family:
333  
        auto [ec] = co_await s.connect(endpoint);
333  
        auto [ec] = co_await s.connect(endpoint);
334  
        if (ec) { ... }
334  
        if (ec) { ... }
335  
        @endcode
335  
        @endcode
336  
    */
336  
    */
337  
    auto connect(endpoint ep)
337  
    auto connect(endpoint ep)
338  
    {
338  
    {
339  
        if (!is_open())
339  
        if (!is_open())
340  
            open(ep.is_v6() ? tcp::v6() : tcp::v4());
340  
            open(ep.is_v6() ? tcp::v6() : tcp::v4());
341  
        return connect_awaitable(*this, ep);
341  
        return connect_awaitable(*this, ep);
342  
    }
342  
    }
343  

343  

344  
    /** Cancel any pending asynchronous operations.
344  
    /** Cancel any pending asynchronous operations.
345  

345  

346  
        All outstanding operations complete with `errc::operation_canceled`.
346  
        All outstanding operations complete with `errc::operation_canceled`.
347  
        Check `ec == cond::canceled` for portable comparison.
347  
        Check `ec == cond::canceled` for portable comparison.
348  
    */
348  
    */
349  
    void cancel();
349  
    void cancel();
350  

350  

351  
    /** Get the native socket handle.
351  
    /** Get the native socket handle.
352  

352  

353  
        Returns the underlying platform-specific socket descriptor.
353  
        Returns the underlying platform-specific socket descriptor.
354  
        On POSIX systems this is an `int` file descriptor.
354  
        On POSIX systems this is an `int` file descriptor.
355  
        On Windows this is a `SOCKET` handle.
355  
        On Windows this is a `SOCKET` handle.
356  

356  

357  
        @return The native socket handle, or -1/INVALID_SOCKET if not open.
357  
        @return The native socket handle, or -1/INVALID_SOCKET if not open.
358  

358  

359  
        @par Preconditions
359  
        @par Preconditions
360  
        None. May be called on closed sockets.
360  
        None. May be called on closed sockets.
361  
    */
361  
    */
362  
    native_handle_type native_handle() const noexcept;
362  
    native_handle_type native_handle() const noexcept;
363  

363  

364  
    /** Disable sends or receives on the socket.
364  
    /** Disable sends or receives on the socket.
365  

365  

366  
        TCP connections are full-duplex: each direction (send and receive)
366  
        TCP connections are full-duplex: each direction (send and receive)
367  
        operates independently. This function allows you to close one or
367  
        operates independently. This function allows you to close one or
368  
        both directions without destroying the socket.
368  
        both directions without destroying the socket.
369  

369  

370  
        @li @ref shutdown_send sends a TCP FIN packet to the peer,
370  
        @li @ref shutdown_send sends a TCP FIN packet to the peer,
371  
            signaling that you have no more data to send. You can still
371  
            signaling that you have no more data to send. You can still
372  
            receive data until the peer also closes their send direction.
372  
            receive data until the peer also closes their send direction.
373  
            This is the most common use case, typically called before
373  
            This is the most common use case, typically called before
374  
            close() to ensure graceful connection termination.
374  
            close() to ensure graceful connection termination.
375  

375  

376  
        @li @ref shutdown_receive disables reading on the socket. This
376  
        @li @ref shutdown_receive disables reading on the socket. This
377  
            does NOT send anything to the peer - they are not informed
377  
            does NOT send anything to the peer - they are not informed
378  
            and may continue sending data. Subsequent reads will fail
378  
            and may continue sending data. Subsequent reads will fail
379  
            or return end-of-file. Incoming data may be discarded or
379  
            or return end-of-file. Incoming data may be discarded or
380  
            buffered depending on the operating system.
380  
            buffered depending on the operating system.
381  

381  

382  
        @li @ref shutdown_both combines both effects: sends a FIN and
382  
        @li @ref shutdown_both combines both effects: sends a FIN and
383  
            disables reading.
383  
            disables reading.
384  

384  

385  
        When the peer shuts down their send direction (sends a FIN),
385  
        When the peer shuts down their send direction (sends a FIN),
386  
        subsequent read operations will complete with `capy::cond::eof`.
386  
        subsequent read operations will complete with `capy::cond::eof`.
387  
        Use the portable condition test rather than comparing error
387  
        Use the portable condition test rather than comparing error
388  
        codes directly:
388  
        codes directly:
389  

389  

390  
        @code
390  
        @code
391  
        auto [ec, n] = co_await sock.read_some(buffer);
391  
        auto [ec, n] = co_await sock.read_some(buffer);
392  
        if (ec == capy::cond::eof)
392  
        if (ec == capy::cond::eof)
393  
        {
393  
        {
394  
            // Peer closed their send direction
394  
            // Peer closed their send direction
395  
        }
395  
        }
396  
        @endcode
396  
        @endcode
397  

397  

398  
        Any error from the underlying system call is silently discarded
398  
        Any error from the underlying system call is silently discarded
399  
        because it is unlikely to be helpful.
399  
        because it is unlikely to be helpful.
400  

400  

401  
        @param what Determines what operations will no longer be allowed.
401  
        @param what Determines what operations will no longer be allowed.
402  
    */
402  
    */
403  
    void shutdown(shutdown_type what);
403  
    void shutdown(shutdown_type what);
404  

404  

405  
    /** Set a socket option.
405  
    /** Set a socket option.
406  

406  

407  
        Applies a type-safe socket option to the underlying socket.
407  
        Applies a type-safe socket option to the underlying socket.
408  
        The option type encodes the protocol level and option name.
408  
        The option type encodes the protocol level and option name.
409  

409  

410  
        @par Example
410  
        @par Example
411  
        @code
411  
        @code
412  
        sock.set_option( socket_option::no_delay( true ) );
412  
        sock.set_option( socket_option::no_delay( true ) );
413  
        sock.set_option( socket_option::receive_buffer_size( 65536 ) );
413  
        sock.set_option( socket_option::receive_buffer_size( 65536 ) );
414  
        @endcode
414  
        @endcode
415  

415  

416  
        @param opt The option to set.
416  
        @param opt The option to set.
417  

417  

418  
        @throws std::logic_error if the socket is not open.
418  
        @throws std::logic_error if the socket is not open.
419  
        @throws std::system_error on failure.
419  
        @throws std::system_error on failure.
420  
    */
420  
    */
421  
    template<class Option>
421  
    template<class Option>
422  
    void set_option(Option const& opt)
422  
    void set_option(Option const& opt)
423  
    {
423  
    {
424  
        if (!is_open())
424  
        if (!is_open())
425  
            detail::throw_logic_error("set_option: socket not open");
425  
            detail::throw_logic_error("set_option: socket not open");
426  
        std::error_code ec = get().set_option(
426  
        std::error_code ec = get().set_option(
427  
            Option::level(), Option::name(), opt.data(), opt.size());
427  
            Option::level(), Option::name(), opt.data(), opt.size());
428  
        if (ec)
428  
        if (ec)
429  
            detail::throw_system_error(ec, "tcp_socket::set_option");
429  
            detail::throw_system_error(ec, "tcp_socket::set_option");
430  
    }
430  
    }
431  

431  

432  
    /** Get a socket option.
432  
    /** Get a socket option.
433  

433  

434  
        Retrieves the current value of a type-safe socket option.
434  
        Retrieves the current value of a type-safe socket option.
435  

435  

436  
        @par Example
436  
        @par Example
437  
        @code
437  
        @code
438  
        auto nd = sock.get_option<socket_option::no_delay>();
438  
        auto nd = sock.get_option<socket_option::no_delay>();
439  
        if ( nd.value() )
439  
        if ( nd.value() )
440  
            // Nagle's algorithm is disabled
440  
            // Nagle's algorithm is disabled
441  
        @endcode
441  
        @endcode
442  

442  

443  
        @return The current option value.
443  
        @return The current option value.
444  

444  

445  
        @throws std::logic_error if the socket is not open.
445  
        @throws std::logic_error if the socket is not open.
446  
        @throws std::system_error on failure.
446  
        @throws std::system_error on failure.
447  
    */
447  
    */
448  
    template<class Option>
448  
    template<class Option>
449  
    Option get_option() const
449  
    Option get_option() const
450  
    {
450  
    {
451  
        if (!is_open())
451  
        if (!is_open())
452  
            detail::throw_logic_error("get_option: socket not open");
452  
            detail::throw_logic_error("get_option: socket not open");
453  
        Option opt{};
453  
        Option opt{};
454  
        std::size_t sz = opt.size();
454  
        std::size_t sz = opt.size();
455  
        std::error_code ec =
455  
        std::error_code ec =
456  
            get().get_option(Option::level(), Option::name(), opt.data(), &sz);
456  
            get().get_option(Option::level(), Option::name(), opt.data(), &sz);
457  
        if (ec)
457  
        if (ec)
458  
            detail::throw_system_error(ec, "tcp_socket::get_option");
458  
            detail::throw_system_error(ec, "tcp_socket::get_option");
459  
        opt.resize(sz);
459  
        opt.resize(sz);
460  
        return opt;
460  
        return opt;
461  
    }
461  
    }
462  

462  

463  
    /** Get the local endpoint of the socket.
463  
    /** Get the local endpoint of the socket.
464  

464  

465  
        Returns the local address and port to which the socket is bound.
465  
        Returns the local address and port to which the socket is bound.
466  
        For a connected socket, this is the local side of the connection.
466  
        For a connected socket, this is the local side of the connection.
467  
        The endpoint is cached when the connection is established.
467  
        The endpoint is cached when the connection is established.
468  

468  

469  
        @return The local endpoint, or a default endpoint (0.0.0.0:0) if
469  
        @return The local endpoint, or a default endpoint (0.0.0.0:0) if
470  
            the socket is not connected.
470  
            the socket is not connected.
471  

471  

472  
        @par Thread Safety
472  
        @par Thread Safety
473  
        The cached endpoint value is set during connect/accept completion
473  
        The cached endpoint value is set during connect/accept completion
474  
        and cleared during close(). This function may be called concurrently
474  
        and cleared during close(). This function may be called concurrently
475  
        with I/O operations, but must not be called concurrently with
475  
        with I/O operations, but must not be called concurrently with
476  
        connect(), accept(), or close().
476  
        connect(), accept(), or close().
477  
    */
477  
    */
478  
    endpoint local_endpoint() const noexcept;
478  
    endpoint local_endpoint() const noexcept;
479  

479  

480  
    /** Get the remote endpoint of the socket.
480  
    /** Get the remote endpoint of the socket.
481  

481  

482  
        Returns the remote address and port to which the socket is connected.
482  
        Returns the remote address and port to which the socket is connected.
483  
        The endpoint is cached when the connection is established.
483  
        The endpoint is cached when the connection is established.
484  

484  

485  
        @return The remote endpoint, or a default endpoint (0.0.0.0:0) if
485  
        @return The remote endpoint, or a default endpoint (0.0.0.0:0) if
486  
            the socket is not connected.
486  
            the socket is not connected.
487  

487  

488  
        @par Thread Safety
488  
        @par Thread Safety
489  
        The cached endpoint value is set during connect/accept completion
489  
        The cached endpoint value is set during connect/accept completion
490  
        and cleared during close(). This function may be called concurrently
490  
        and cleared during close(). This function may be called concurrently
491  
        with I/O operations, but must not be called concurrently with
491  
        with I/O operations, but must not be called concurrently with
492  
        connect(), accept(), or close().
492  
        connect(), accept(), or close().
493  
    */
493  
    */
494  
    endpoint remote_endpoint() const noexcept;
494  
    endpoint remote_endpoint() const noexcept;
495  

495  

496  
protected:
496  
protected:
497  
    tcp_socket() noexcept = default;
497  
    tcp_socket() noexcept = default;
498  

498  

499  
    explicit tcp_socket(handle h) noexcept : io_object(std::move(h)) {}
499  
    explicit tcp_socket(handle h) noexcept : io_object(std::move(h)) {}
500  

500  

501  
private:
501  
private:
502  
    friend class tcp_acceptor;
502  
    friend class tcp_acceptor;
503  

503  

504  
    /// Open the socket for the given protocol triple.
504  
    /// Open the socket for the given protocol triple.
505  
    void open_for_family(int family, int type, int protocol);
505  
    void open_for_family(int family, int type, int protocol);
506  

506  

507  
    inline implementation& get() const noexcept
507  
    inline implementation& get() const noexcept
508  
    {
508  
    {
509  
        return *static_cast<implementation*>(h_.get());
509  
        return *static_cast<implementation*>(h_.get());
510  
    }
510  
    }
511  
};
511  
};
512  

512  

513  
} // namespace boost::corosio
513  
} // namespace boost::corosio
514  

514  

515  
#endif
515  
#endif