. /include/boost/corosio /tcp_acceptor.hpp
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1   // 1   //
2   // Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com) 2   // Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
3   // Copyright (c) 2026 Steve Gerbino 3   // Copyright (c) 2026 Steve Gerbino
4   // Copyright (c) 2026 Michael Vandeberg 4   // Copyright (c) 2026 Michael Vandeberg
5   // 5   //
6   // Distributed under the Boost Software License, Version 1.0. (See accompanying 6   // Distributed under the Boost Software License, Version 1.0. (See accompanying
7   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 7   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
8   // 8   //
9   // Official repository: https://github.com/cppalliance/corosio 9   // Official repository: https://github.com/cppalliance/corosio
10   // 10   //
11   11  
12   #ifndef BOOST_COROSIO_TCP_ACCEPTOR_HPP 12   #ifndef BOOST_COROSIO_TCP_ACCEPTOR_HPP
13   #define BOOST_COROSIO_TCP_ACCEPTOR_HPP 13   #define BOOST_COROSIO_TCP_ACCEPTOR_HPP
14   14  
15   #include <boost/corosio/family.hpp> 15   #include <boost/corosio/family.hpp>
16   #include <boost/corosio/detail/config.hpp> 16   #include <boost/corosio/detail/config.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/error.hpp> 19   #include <boost/corosio/error.hpp>
20   #include <boost/corosio/wait_type.hpp> 20   #include <boost/corosio/wait_type.hpp>
21   #include <boost/corosio/io/io_object.hpp> 21   #include <boost/corosio/io/io_object.hpp>
22   #include <boost/capy/results.hpp> 22   #include <boost/capy/results.hpp>
23   #include <boost/corosio/endpoint.hpp> 23   #include <boost/corosio/endpoint.hpp>
24   #include <boost/corosio/tcp_socket.hpp> 24   #include <boost/corosio/tcp_socket.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/await_context.hpp> 27   #include <boost/capy/ex/await_context.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 <boost/capy/continuation.hpp> 33   #include <boost/capy/continuation.hpp>
34   34  
35   #include <coroutine> 35   #include <coroutine>
36   #include <cstddef> 36   #include <cstddef>
37   #include <stop_token> 37   #include <stop_token>
38   #include <type_traits> 38   #include <type_traits>
39   #include <utility> 39   #include <utility>
40   40  
41   namespace boost::corosio { 41   namespace boost::corosio {
42   42  
43   /** Accepts inbound TCP connections, from a coroutine. 43   /** Accepts inbound TCP connections, from a coroutine.
44   44  
45   This class provides asynchronous TCP accept operations that return 45   This class provides asynchronous TCP accept operations that return
46   awaitable types. The acceptor binds to a local endpoint and listens 46   awaitable types. The acceptor binds to a local endpoint and listens
47   for incoming connections. 47   for incoming connections.
48   48  
49   Each accept operation participates in the affine awaitable protocol, 49   Each accept operation participates in the affine awaitable protocol,
50   ensuring coroutines resume on the correct executor. 50   ensuring coroutines resume on the correct executor.
51   51  
52   @par Thread Safety 52   @par Thread Safety
53   Distinct objects: Safe.@n 53   Distinct objects: Safe.@n
54   Shared objects: Unsafe. An acceptor must not have concurrent accept 54   Shared objects: Unsafe. An acceptor must not have concurrent accept
55   operations. 55   operations.
56   56  
57   @par Semantics 57   @par Semantics
58   Wraps the platform TCP listener. Operations dispatch to 58   Wraps the platform TCP listener. Operations dispatch to
59   OS accept APIs via the `io_context` reactor. 59   OS accept APIs via the `io_context` reactor.
60   60  
61   @par Example 61   @par Example
62   @par !example convenience_construction 62   @par !example convenience_construction
63   63  
64   @par Example 64   @par Example
65   @par !example fine_grained_setup 65   @par !example fine_grained_setup
66   */ 66   */
67   class BOOST_COROSIO_DECL tcp_acceptor : public io_object 67   class BOOST_COROSIO_DECL tcp_acceptor : public io_object
68   { 68   {
69   struct wait_awaitable : detail::void_op_base<wait_awaitable> 69   struct wait_awaitable : detail::void_op_base<wait_awaitable>
70   { 70   {
71   private: 71   private:
72   friend tcp_acceptor; 72   friend tcp_acceptor;
73   73  
HITCBC 74   31 wait_awaitable(tcp_acceptor& acc, wait_type w) noexcept 74   31 wait_awaitable(tcp_acceptor& acc, wait_type w) noexcept
HITCBC 75   62 : acc_(acc) 75   62 : acc_(acc)
HITCBC 76   31 , w_(w) 76   31 , w_(w)
77   { 77   {
HITCBC 78   31 } 78   31 }
79   79  
80   friend detail::void_op_base<wait_awaitable>; 80   friend detail::void_op_base<wait_awaitable>;
81   81  
82   tcp_acceptor& acc_; 82   tcp_acceptor& acc_;
83   wait_type w_; 83   wait_type w_;
84   84  
85   std::coroutine_handle<> 85   std::coroutine_handle<>
HITCBC 86   27 dispatch(capy::continuation& cont, capy::executor_ref ex) const 86   27 dispatch(capy::continuation& cont, capy::executor_ref ex) const
87   { 87   {
HITCBC 88   27 return acc_.get().wait(cont, ex, w_, token_, &ec_); 88   27 return acc_.get().wait(cont, ex, w_, token_, &ec_);
89   } 89   }
90   }; 90   };
91   91  
92   struct accept_awaitable : detail::void_op_base<accept_awaitable> 92   struct accept_awaitable : detail::void_op_base<accept_awaitable>
93   { 93   {
94   private: 94   private:
95   friend tcp_acceptor; 95   friend tcp_acceptor;
96   friend detail::void_op_base<accept_awaitable>; 96   friend detail::void_op_base<accept_awaitable>;
97   97  
98   tcp_acceptor& acc_; 98   tcp_acceptor& acc_;
99   tcp_socket& peer_; 99   tcp_socket& peer_;
100   mutable io_object::implementation* peer_impl_ = nullptr; 100   mutable io_object::implementation* peer_impl_ = nullptr;
101   101  
102   102  
HITCBC 103   7210 accept_awaitable(tcp_acceptor& acc, tcp_socket& peer) noexcept 103   7399 accept_awaitable(tcp_acceptor& acc, tcp_socket& peer) noexcept
HITCBC 104   14420 : acc_(acc) 104   14798 : acc_(acc)
HITCBC 105   7210 , peer_(peer) 105   7399 , peer_(peer)
106   { 106   {
HITCBC 107   7210 } 107   7399 }
108   108  
109   std::coroutine_handle<> 109   std::coroutine_handle<>
HITCBC 110   7201 dispatch(capy::continuation& cont, capy::executor_ref ex) const 110   7389 dispatch(capy::continuation& cont, capy::executor_ref ex) const
111   { 111   {
HITCBC 112   21603 return acc_.get().accept( 112   22167 return acc_.get().accept(
HITCBC 113   21603 cont, ex, this->token_, &this->ec_, &peer_impl_); 113   22167 cont, ex, this->token_, &this->ec_, &peer_impl_);
114   } 114   }
115   115  
116   public: 116   public:
117   // A peer accepted for an awaiter that never resumed is closed 117   // A peer accepted for an awaiter that never resumed is closed
118   // here, or nothing would own it. 118   // here, or nothing would own it.
HITCBC 119   14420 ~accept_awaitable() 119   14798 ~accept_awaitable()
120   { 120   {
HITCBC 121   14420 if (peer_impl_) 121   14798 if (peer_impl_)
HITCBC 122   2 discard_peer(acc_, peer_impl_); 122   2 discard_peer(acc_, peer_impl_);
HITCBC 123   14420 } 123   14798 }
124   124  
HITCBC 125   6398 [[nodiscard]] capy::results<> await_resume() const noexcept 125   6587 [[nodiscard]] capy::results<> await_resume() const noexcept
126   { 126   {
HITCBC 127   6398 if (!this->ec_ && peer_impl_) 127   6587 if (!this->ec_ && peer_impl_)
HITCBC 128   6232 peer_.h_.reset(std::exchange(peer_impl_, nullptr)); 128   6426 peer_.h_.reset(std::exchange(peer_impl_, nullptr));
HITCBC 129   6398 return {this->ec_}; 129   6587 return {this->ec_};
130   } 130   }
131   }; 131   };
132   132  
133   struct accept_value_awaitable : detail::void_op_base<accept_value_awaitable> 133   struct accept_value_awaitable : detail::void_op_base<accept_value_awaitable>
134   { 134   {
135   private: 135   private:
136   friend tcp_acceptor; 136   friend tcp_acceptor;
137   friend detail::void_op_base<accept_value_awaitable>; 137   friend detail::void_op_base<accept_value_awaitable>;
138   138  
139   tcp_acceptor& acc_; 139   tcp_acceptor& acc_;
140   mutable io_object::implementation* peer_impl_ = nullptr; 140   mutable io_object::implementation* peer_impl_ = nullptr;
141   141  
142   142  
HITCBC 143   41 explicit accept_value_awaitable(tcp_acceptor& acc) noexcept : acc_(acc) 143   41 explicit accept_value_awaitable(tcp_acceptor& acc) noexcept : acc_(acc)
144   { 144   {
HITCBC 145   41 } 145   41 }
146   146  
147   std::coroutine_handle<> 147   std::coroutine_handle<>
HITCBC 148   37 dispatch(capy::continuation& cont, capy::executor_ref ex) const 148   37 dispatch(capy::continuation& cont, capy::executor_ref ex) const
149   { 149   {
HITCBC 150   111 return acc_.get().accept( 150   111 return acc_.get().accept(
HITCBC 151   111 cont, ex, this->token_, &this->ec_, &peer_impl_); 151   111 cont, ex, this->token_, &this->ec_, &peer_impl_);
152   } 152   }
153   153  
154   public: 154   public:
155   // A peer accepted for an awaiter that never resumed is closed 155   // A peer accepted for an awaiter that never resumed is closed
156   // here, or nothing would own it. 156   // here, or nothing would own it.
HITCBC 157   82 ~accept_value_awaitable() 157   82 ~accept_value_awaitable()
158   { 158   {
HITCBC 159   82 if (peer_impl_) 159   82 if (peer_impl_)
HITCBC 160   2 discard_peer(acc_, peer_impl_); 160   2 discard_peer(acc_, peer_impl_);
HITCBC 161   82 } 161   82 }
162   162  
HITCBC 163   31 [[nodiscard]] capy::results<tcp_socket> await_resume() noexcept 163   31 [[nodiscard]] capy::results<tcp_socket> await_resume() noexcept
164   { 164   {
HITCBC 165   31 return take_peer(acc_, this->ec_, peer_impl_); 165   31 return take_peer(acc_, this->ec_, peer_impl_);
166   } 166   }
167   }; 167   };
168   168  
169   public: 169   public:
170   /** Closes the acceptor if open, cancelling any pending operations. 170   /** Closes the acceptor if open, cancelling any pending operations.
171   */ 171   */
172   ~tcp_acceptor() override; 172   ~tcp_acceptor() override;
173   173  
174   /** Construct an acceptor from an execution context. 174   /** Construct an acceptor from an execution context.
175   175  
176   @param ctx The execution context that owns this acceptor. 176   @param ctx The execution context that owns this acceptor.
177   */ 177   */
178   explicit tcp_acceptor(capy::execution_context& ctx); 178   explicit tcp_acceptor(capy::execution_context& ctx);
179   179  
180   /** Convenience constructor: open + configure + bind + listen. 180   /** Convenience constructor: open + configure + bind + listen.
181   181  
182   Creates a fully bound listening acceptor in a single 182   Creates a fully bound listening acceptor in a single
183   expression, throwing the codes the piecewise `open()` + 183   expression, throwing the codes the piecewise `open()` +
184   `set_option()` + `bind()` + `listen()` path reports. The 184   `set_option()` + `bind()` + `listen()` path reports. The
185   address family is deduced from @p ep. 185   address family is deduced from @p ep.
186   186  
187   Before binding, the constructor configures address reuse so a 187   Before binding, the constructor configures address reuse so a
188   server can rebind its port immediately after a restart. It 188   server can rebind its port immediately after a restart. It
189   sets `SO_REUSEADDR` on POSIX and `SO_EXCLUSIVEADDRUSE` on 189   sets `SO_REUSEADDR` on POSIX and `SO_EXCLUSIVEADDRUSE` on
190   Windows. Windows does not use `SO_REUSEADDR` because it 190   Windows. Windows does not use `SO_REUSEADDR` because it
191   instead grants other sockets bind-over rights. A second 191   instead grants other sockets bind-over rights. A second
192   listener on an occupied endpoint therefore throws 192   listener on an occupied endpoint therefore throws
193   `errc::address_in_use` on every platform. 193   `errc::address_in_use` on every platform.
194   194  
195   @param ctx The execution context that owns this acceptor. 195   @param ctx The execution context that owns this acceptor.
196   @param ep The local endpoint to bind to. 196   @param ep The local endpoint to bind to.
197   @param backlog The maximum pending connection queue length. 197   @param backlog The maximum pending connection queue length.
198   198  
199   @throws std::system_error on open, configuration, bind, or 199   @throws std::system_error on open, configuration, bind, or
200   listen failure. 200   listen failure.
201   */ 201   */
202   tcp_acceptor(capy::execution_context& ctx, endpoint ep, int backlog = 128); 202   tcp_acceptor(capy::execution_context& ctx, endpoint ep, int backlog = 128);
203   203  
204   /** Construct an acceptor from an executor. 204   /** Construct an acceptor from an executor.
205   205  
206   The acceptor is associated with the executor's context. `Ex` 206   The acceptor is associated with the executor's context. `Ex`
207   must satisfy `capy::Executor`. 207   must satisfy `capy::Executor`.
208   208  
209   @param ex The executor whose context owns the acceptor. 209   @param ex The executor whose context owns the acceptor.
210   */ 210   */
211   template<class Ex> 211   template<class Ex>
212   requires(!std::same_as<std::remove_cvref_t<Ex>, tcp_acceptor>) && 212   requires(!std::same_as<std::remove_cvref_t<Ex>, tcp_acceptor>) &&
213   capy::Executor<Ex> 213   capy::Executor<Ex>
HITCBC 214   1 explicit tcp_acceptor(Ex const& ex) : tcp_acceptor(ex.context()) 214   1 explicit tcp_acceptor(Ex const& ex) : tcp_acceptor(ex.context())
215   { 215   {
HITCBC 216   1 } 216   1 }
217   217  
218   /** Convenience constructor from an executor. 218   /** Convenience constructor from an executor.
219   219  
220   Creates a fully bound listening acceptor in a single 220   Creates a fully bound listening acceptor in a single
221   expression, throwing the codes the piecewise `open()` + 221   expression, throwing the codes the piecewise `open()` +
222   `set_option()` + `bind()` + `listen()` path reports. The 222   `set_option()` + `bind()` + `listen()` path reports. The
223   address family is deduced from @p ep. 223   address family is deduced from @p ep.
224   224  
225   Before binding, the constructor configures address reuse so a 225   Before binding, the constructor configures address reuse so a
226   server can rebind its port immediately after a restart. It 226   server can rebind its port immediately after a restart. It
227   sets `SO_REUSEADDR` on POSIX and `SO_EXCLUSIVEADDRUSE` on 227   sets `SO_REUSEADDR` on POSIX and `SO_EXCLUSIVEADDRUSE` on
228   Windows. Windows does not use `SO_REUSEADDR` because it 228   Windows. Windows does not use `SO_REUSEADDR` because it
229   instead grants other sockets bind-over rights. A second 229   instead grants other sockets bind-over rights. A second
230   listener on an occupied endpoint therefore throws 230   listener on an occupied endpoint therefore throws
231   `errc::address_in_use` on every platform. 231   `errc::address_in_use` on every platform.
232   232  
233   `Ex` must satisfy `capy::Executor`. 233   `Ex` must satisfy `capy::Executor`.
234   234  
235   @param ex The executor whose context owns the acceptor. 235   @param ex The executor whose context owns the acceptor.
236   @param ep The local endpoint to bind to. 236   @param ep The local endpoint to bind to.
237   @param backlog The maximum pending connection queue length. 237   @param backlog The maximum pending connection queue length.
238   238  
239   @throws std::system_error on open, configuration, bind, or 239   @throws std::system_error on open, configuration, bind, or
240   listen failure. 240   listen failure.
241   */ 241   */
242   template<class Ex> 242   template<class Ex>
243   requires capy::Executor<Ex> 243   requires capy::Executor<Ex>
244   tcp_acceptor(Ex const& ex, endpoint ep, int backlog = 128) 244   tcp_acceptor(Ex const& ex, endpoint ep, int backlog = 128)
245   : tcp_acceptor(ex.context(), ep, backlog) 245   : tcp_acceptor(ex.context(), ep, backlog)
246   { 246   {
247   } 247   }
248   248  
249   /** Transfers ownership of the acceptor resources. 249   /** Transfers ownership of the acceptor resources.
250   250  
251   @param other The acceptor to move from. 251   @param other The acceptor to move from.
252   252  
253   @pre No awaitables returned by @p other's methods exist. 253   @pre No awaitables returned by @p other's methods exist.
254   @pre The execution context associated with @p other must 254   @pre The execution context associated with @p other must
255   outlive this acceptor. 255   outlive this acceptor.
256   */ 256   */
HITCBC 257   182 tcp_acceptor(tcp_acceptor&& other) noexcept : io_object(std::move(other)) {} 257   182 tcp_acceptor(tcp_acceptor&& other) noexcept : io_object(std::move(other)) {}
258   258  
259   /** Closes any existing acceptor and transfers ownership. 259   /** Closes any existing acceptor and transfers ownership.
260   260  
261   @param other The acceptor to move from. 261   @param other The acceptor to move from.
262   262  
263   @pre No awaitables returned by either `*this` or @p other's 263   @pre No awaitables returned by either `*this` or @p other's
264   methods exist. 264   methods exist.
265   @pre The execution context associated with @p other must 265   @pre The execution context associated with @p other must
266   outlive this acceptor. 266   outlive this acceptor.
267   267  
268   @return Reference to this acceptor. 268   @return Reference to this acceptor.
269   */ 269   */
HITCBC 270   3 tcp_acceptor& operator=(tcp_acceptor&& other) noexcept 270   3 tcp_acceptor& operator=(tcp_acceptor&& other) noexcept
271   { 271   {
HITCBC 272   3 if (this != &other) 272   3 if (this != &other)
273   { 273   {
HITCBC 274   3 close(); 274   3 close();
HITCBC 275   3 h_ = std::move(other.h_); 275   3 h_ = std::move(other.h_);
276   } 276   }
HITCBC 277   3 return *this; 277   3 return *this;
278   } 278   }
279   279  
280   /// Copy construction is disabled; the handle is uniquely owned. 280   /// Copy construction is disabled; the handle is uniquely owned.
281   tcp_acceptor(tcp_acceptor const&) = delete; 281   tcp_acceptor(tcp_acceptor const&) = delete;
282   /// Copy assignment is disabled; the handle is uniquely owned. 282   /// Copy assignment is disabled; the handle is uniquely owned.
283   tcp_acceptor& operator=(tcp_acceptor const&) = delete; 283   tcp_acceptor& operator=(tcp_acceptor const&) = delete;
284   284  
285   /** Create the acceptor socket without binding or listening. 285   /** Create the acceptor socket without binding or listening.
286   286  
287   Creates a TCP socket with dual-stack enabled for IPv6. 287   Creates a TCP socket with dual-stack enabled for IPv6.
288   Does not set SO_REUSEADDR. Call `set_option` explicitly 288   Does not set SO_REUSEADDR. Call `set_option` explicitly
289   if needed. 289   if needed.
290   290  
291   If the acceptor is already open, this function is a no-op. 291   If the acceptor is already open, this function is a no-op.
292   292  
293   Failures such as descriptor exhaustion are normal runtime 293   Failures such as descriptor exhaustion are normal runtime
294   conditions and are reported through the returned error code. 294   conditions and are reported through the returned error code.
295   295  
296   @param f The address family (IPv4 or IPv6). Defaults to 296   @param f The address family (IPv4 or IPv6). Defaults to
297   `family::v4`. 297   `family::v4`.
298   298  
299   @par Example 299   @par Example
300   @par !example open 300   @par !example open
301   301  
302   @see @ref bind, @ref listen 302   @see @ref bind, @ref listen
303   303  
304   @return The error code, empty on success. 304   @return The error code, empty on success.
305   */ 305   */
306   [[nodiscard]] std::error_code open(family f = family::v4) noexcept; 306   [[nodiscard]] std::error_code open(family f = family::v4) noexcept;
307   307  
308   /** Bind to a local endpoint. 308   /** Bind to a local endpoint.
309   309  
310   The acceptor must be open. Binds the socket to @p ep and 310   The acceptor must be open. Binds the socket to @p ep and
311   caches the resolved local endpoint (useful when port 0 is 311   caches the resolved local endpoint (useful when port 0 is
312   used to request an ephemeral port). 312   used to request an ephemeral port).
313   313  
314   @param ep The local endpoint to bind to. 314   @param ep The local endpoint to bind to.
315   315  
316   @return An error code indicating success or the reason for 316   @return An error code indicating success or the reason for
317   failure. 317   failure.
318   318  
319   @par Error Conditions 319   @par Error Conditions
320   @li `errc::address_in_use`: The endpoint is already in use. 320   @li `errc::address_in_use`: The endpoint is already in use.
321   @li `errc::address_not_available`: The address is not available 321   @li `errc::address_not_available`: The address is not available
322   on any local interface. 322   on any local interface.
323   @li `errc::permission_denied`: Insufficient privileges to bind 323   @li `errc::permission_denied`: Insufficient privileges to bind
324   to the endpoint (e.g., privileged port). 324   to the endpoint (e.g., privileged port).
325   @li `errc::bad_file_descriptor`: The acceptor is not open. 325   @li `errc::bad_file_descriptor`: The acceptor is not open.
326   */ 326   */
327   [[nodiscard]] std::error_code bind(endpoint ep) noexcept; 327   [[nodiscard]] std::error_code bind(endpoint ep) noexcept;
328   328  
329   /** Start listening for incoming connections. 329   /** Start listening for incoming connections.
330   330  
331   The acceptor must be open and bound. Registers the acceptor 331   The acceptor must be open and bound. Registers the acceptor
332   with the platform reactor. 332   with the platform reactor.
333   333  
334   @param backlog The maximum length of the queue of pending 334   @param backlog The maximum length of the queue of pending
335   connections. Defaults to 128. 335   connections. Defaults to 128.
336   336  
337   @return An error code indicating success or the reason for 337   @return An error code indicating success or the reason for
338   failure. 338   failure.
339   339  
340   A closed acceptor reports `errc::bad_file_descriptor`. 340   A closed acceptor reports `errc::bad_file_descriptor`.
341   */ 341   */
342   [[nodiscard]] std::error_code listen(int backlog = 128) noexcept; 342   [[nodiscard]] std::error_code listen(int backlog = 128) noexcept;
343   343  
344   /** Close the acceptor. 344   /** Close the acceptor.
345   345  
346   Releases acceptor resources. Any pending operations complete 346   Releases acceptor resources. Any pending operations complete
347   with `errc::operation_canceled`. 347   with `errc::operation_canceled`.
348   */ 348   */
349   void close() noexcept; 349   void close() noexcept;
350   350  
351   /** Check if the acceptor is listening. 351   /** Check if the acceptor is listening.
352   352  
353   @return `true` if the acceptor is open and listening. 353   @return `true` if the acceptor is open and listening.
354   */ 354   */
HITCBC 355   20977 bool is_open() const noexcept 355   21166 bool is_open() const noexcept
356   { 356   {
HITCBC 357   20977 return h_ && get().is_open(); 357   21166 return h_ && get().is_open();
358   } 358   }
359   359  
360   /** Initiate an asynchronous accept operation. 360   /** Initiate an asynchronous accept operation.
361   361  
362   Accepts an incoming connection and initializes the provided 362   Accepts an incoming connection and initializes the provided
363   socket with the new connection. The acceptor must be listening 363   socket with the new connection. The acceptor must be listening
364   before calling this function. 364   before calling this function.
365   365  
366   The operation supports cancellation via `std::stop_token` through 366   The operation supports cancellation via `std::stop_token` through
367   the affine awaitable protocol. If the associated stop token is 367   the affine awaitable protocol. If the associated stop token is
368   triggered, the operation completes immediately with 368   triggered, the operation completes immediately with
369   `errc::operation_canceled`. 369   `errc::operation_canceled`.
370   370  
371   @param peer The socket to receive the accepted connection. Any 371   @param peer The socket to receive the accepted connection. Any
372   existing connection on this socket is closed. 372   existing connection on this socket is closed.
373   373  
374   @return An awaitable that completes with `results<>`. 374   @return An awaitable that completes with `results<>`.
375   Returns success on successful accept, or an error code on 375   Returns success on successful accept, or an error code on
376   failure including: 376   failure including:
377   - `operation_canceled`: Cancelled via stop_token or cancel(). 377   - `operation_canceled`: Cancelled via stop_token or cancel().
378   Check `ec == cond::canceled` for portable comparison. 378   Check `ec == cond::canceled` for portable comparison.
379   379  
380   A closed acceptor completes with `errc::bad_file_descriptor`. 380   A closed acceptor completes with `errc::bad_file_descriptor`.
381   381  
382   @pre The peer socket must be associated with the same execution context. 382   @pre The peer socket must be associated with the same execution context.
383   383  
384   Both this acceptor and @p peer must outlive the returned 384   Both this acceptor and @p peer must outlive the returned
385   awaitable. 385   awaitable.
386   386  
387   @par Example 387   @par Example
388   @par !example accept_into_a_reused_socket 388   @par !example accept_into_a_reused_socket
389   389  
390   @see @ref accept() 390   @see @ref accept()
391   */ 391   */
HITCBC 392   7210 [[nodiscard]] auto accept(tcp_socket& peer) 392   7399 [[nodiscard]] auto accept(tcp_socket& peer)
393   { 393   {
HITCBC 394   7210 accept_awaitable aw(*this, peer); 394   7399 accept_awaitable aw(*this, peer);
HITCBC 395   7210 if (!is_open()) 395   7399 if (!is_open())
HITCBC 396   2 aw.ec_ = make_error_code(std::errc::bad_file_descriptor); 396   2 aw.ec_ = make_error_code(std::errc::bad_file_descriptor);
HITCBC 397   7210 return aw; 397   7399 return aw;
398   } 398   }
399   399  
400   /** Initiate an asynchronous accept operation, returning the peer. 400   /** Initiate an asynchronous accept operation, returning the peer.
401   401  
402   Accepts an incoming connection and returns a newly constructed 402   Accepts an incoming connection and returns a newly constructed
403   socket for it, associated with this acceptor's execution context. 403   socket for it, associated with this acceptor's execution context.
404   The acceptor must be listening before calling this function. 404   The acceptor must be listening before calling this function.
405   405  
406   The caller does not pre-construct the peer socket. The returned 406   The caller does not pre-construct the peer socket. The returned
407   socket shares this acceptor's execution context. 407   socket shares this acceptor's execution context.
408   408  
409   The operation supports cancellation via `std::stop_token` through 409   The operation supports cancellation via `std::stop_token` through
410   the affine awaitable protocol. If the associated stop token is 410   the affine awaitable protocol. If the associated stop token is
411   triggered, the operation completes immediately with 411   triggered, the operation completes immediately with
412   `errc::operation_canceled`. 412   `errc::operation_canceled`.
413   413  
414   @return An awaitable that completes with `results<tcp_socket>`. 414   @return An awaitable that completes with `results<tcp_socket>`.
415   On success the payload is the connected peer socket; on failure 415   On success the payload is the connected peer socket; on failure
416   (including cancellation) the error code is set and the payload 416   (including cancellation) the error code is set and the payload
417   socket is unconnected. Errors include: 417   socket is unconnected. Errors include:
418   - `operation_canceled`: Cancelled via stop_token or cancel(). 418   - `operation_canceled`: Cancelled via stop_token or cancel().
419   Check `ec == cond::canceled` for portable comparison. 419   Check `ec == cond::canceled` for portable comparison.
420   420  
421   A closed acceptor completes with `errc::bad_file_descriptor`. 421   A closed acceptor completes with `errc::bad_file_descriptor`.
422   On failure the returned socket is default-constructed and not 422   On failure the returned socket is default-constructed and not
423   open. It has no context, so it may only be destroyed, assigned, 423   open. It has no context, so it may only be destroyed, assigned,
424   or checked with `is_open()`. 424   or checked with `is_open()`.
425   425  
426   @pre This acceptor must outlive the returned awaitable. 426   @pre This acceptor must outlive the returned awaitable.
427   427  
428   @par Example 428   @par Example
429   @par !example accept_returning_a_new_socket 429   @par !example accept_returning_a_new_socket
430   430  
431   @see @ref accept(tcp_socket&) 431   @see @ref accept(tcp_socket&)
432   */ 432   */
HITCBC 433   41 [[nodiscard]] auto accept() 433   41 [[nodiscard]] auto accept()
434   { 434   {
HITCBC 435   41 accept_value_awaitable aw(*this); 435   41 accept_value_awaitable aw(*this);
HITCBC 436   41 if (!is_open()) 436   41 if (!is_open())
HITCBC 437   4 aw.ec_ = make_error_code(std::errc::bad_file_descriptor); 437   4 aw.ec_ = make_error_code(std::errc::bad_file_descriptor);
HITCBC 438   41 return aw; 438   41 return aw;
439   } 439   }
440   440  
441   /** Wait for an incoming connection or readiness condition. 441   /** Wait for an incoming connection or readiness condition.
442   442  
443   Suspends until the listen socket is ready in the 443   Suspends until the listen socket is ready in the
444   requested direction, or an error condition is reported. 444   requested direction, or an error condition is reported.
445   For `wait_type::read`, completion signals that a 445   For `wait_type::read`, completion signals that a
446   subsequent @ref accept succeeds without blocking. A 446   subsequent @ref accept succeeds without blocking. A
447   connection already queued when the wait begins completes 447   connection already queued when the wait begins completes
448   it immediately. No connection is consumed. 448   it immediately. No connection is consumed.
449   449  
450   @note `wait_type::write` is not usable on an acceptor: 450   @note `wait_type::write` is not usable on an acceptor:
451   writability carries no meaning for a listening socket, so 451   writability carries no meaning for a listening socket, so
452   the wait fails with `errc::operation_not_supported` on 452   the wait fails with `errc::operation_not_supported` on
453   every backend. 453   every backend.
454   454  
455   @param w The wait direction. 455   @param w The wait direction.
456   456  
457   @return An awaitable that completes with `results<>`. 457   @return An awaitable that completes with `results<>`.
458   458  
459   A closed acceptor completes with `errc::bad_file_descriptor`. 459   A closed acceptor completes with `errc::bad_file_descriptor`.
460   460  
461   @pre This acceptor must outlive the returned awaitable. 461   @pre This acceptor must outlive the returned awaitable.
462   */ 462   */
HITCBC 463   31 [[nodiscard]] auto wait(wait_type w) 463   31 [[nodiscard]] auto wait(wait_type w)
464   { 464   {
HITCBC 465   31 wait_awaitable aw(*this, w); 465   31 wait_awaitable aw(*this, w);
HITCBC 466   31 if (!is_open()) 466   31 if (!is_open())
HITCBC 467   2 aw.ec_ = make_error_code(std::errc::bad_file_descriptor); 467   2 aw.ec_ = make_error_code(std::errc::bad_file_descriptor);
HITCBC 468   31 return aw; 468   31 return aw;
469   } 469   }
470   470  
471   /** Cancel any pending asynchronous operations. 471   /** Cancel any pending asynchronous operations.
472   472  
473   Accept and wait transfer no bytes, so a cancellation always wins: 473   Accept and wait transfer no bytes, so a cancellation always wins:
474   an operation reports `errc::operation_canceled` even when it had 474   an operation reports `errc::operation_canceled` even when it had
475   already succeeded when the cancellation landed. Check 475   already succeeded when the cancellation landed. Check
476   `ec == cond::canceled` for portable comparison. 476   `ec == cond::canceled` for portable comparison.
477   */ 477   */
478   void cancel() noexcept; 478   void cancel() noexcept;
479   479  
480   /** Get the native socket handle. 480   /** Get the native socket handle.
481   481  
482   Returns the underlying platform-specific socket descriptor. 482   Returns the underlying platform-specific socket descriptor.
483   On POSIX systems this is an `int` file descriptor. 483   On POSIX systems this is an `int` file descriptor.
484   On Windows this is a `SOCKET` handle. 484   On Windows this is a `SOCKET` handle.
485   485  
486   @return The native socket handle, or -1/INVALID_SOCKET if not open. 486   @return The native socket handle, or -1/INVALID_SOCKET if not open.
487   487  
488   @pre None. May be called on closed acceptors. 488   @pre None. May be called on closed acceptors.
489   */ 489   */
490   native_handle_type native_handle() const noexcept; 490   native_handle_type native_handle() const noexcept;
491   491  
492   /** Assign an existing native socket to this acceptor. 492   /** Assign an existing native socket to this acceptor.
493   493  
494   Adopts a listening socket created outside the library. The 494   Adopts a listening socket created outside the library. The
495   socket may come from a service manager, be inherited, or be 495   socket may come from a service manager, be inherited, or be
496   created natively. Adoption registers the socket with the 496   created natively. Adoption registers the socket with the
497   backend. The socket must be a listening stream socket in the 497   backend. The socket must be a listening stream socket in the
498   `AF_INET` or `AF_INET6` family. 498   `AF_INET` or `AF_INET6` family.
499   Adoption never alters the descriptor's flags or options: on 499   Adoption never alters the descriptor's flags or options: on
500   POSIX the fd must already be non-blocking, and on Windows the 500   POSIX the fd must already be non-blocking, and on Windows the
501   socket must be overlapped-capable. 501   socket must be overlapped-capable.
502   502  
503   Adoption does not verify listen state; @ref accept reports the 503   Adoption does not verify listen state; @ref accept reports the
504   error if the socket is not listening. 504   error if the socket is not listening.
505   505  
506   The object must be closed. To replace a held socket, `close()` 506   The object must be closed. To replace a held socket, `close()`
507   or `release()` it first. 507   or `release()` it first.
508   508  
509   @par Exception Safety 509   @par Exception Safety
510   Throws nothing. On failure the object is unchanged and the 510   Throws nothing. On failure the object is unchanged and the
511   caller retains ownership of `fd`. 511   caller retains ownership of `fd`.
512   512  
513   @param fd The native socket to adopt. On success the object 513   @param fd The native socket to adopt. On success the object
514   owns it and closes it. 514   owns it and closes it.
515   515  
516   @return `error::already_open` if this object is open. 516   @return `error::already_open` if this object is open.
517   Otherwise the error code, empty on success. Validation and 517   Otherwise the error code, empty on success. Validation and
518   registration failures are normal runtime conditions when 518   registration failures are normal runtime conditions when
519   adopting foreign descriptors. 519   adopting foreign descriptors.
520   */ 520   */
521   [[nodiscard]] std::error_code assign(native_handle_type fd) noexcept; 521   [[nodiscard]] std::error_code assign(native_handle_type fd) noexcept;
522   522  
523   /** Release ownership of the native socket handle. 523   /** Release ownership of the native socket handle.
524   524  
525   Deregisters the socket from the backend and cancels pending 525   Deregisters the socket from the backend and cancels pending
526   operations without closing the descriptor. The caller takes 526   operations without closing the descriptor. The caller takes
527   ownership of the returned handle. 527   ownership of the returned handle.
528   528  
529   A closed object reports `errc::bad_file_descriptor` and the 529   A closed object reports `errc::bad_file_descriptor` and the
530   returned handle is the invalid sentinel ( -1, or 530   returned handle is the invalid sentinel ( -1, or
531   `INVALID_SOCKET` on Windows ), never zero. 531   `INVALID_SOCKET` on Windows ), never zero.
532   532  
533   @note With the IOCP backend, a socket released while operations 533   @note With the IOCP backend, a socket released while operations
534   on it are in flight stays bound to this context's completion 534   on it are in flight stays bound to this context's completion
535   port for good. Windows refuses to unbind a handle with I/O 535   port for good. Windows refuses to unbind a handle with I/O
536   outstanding, so no context, this one included, can assign it 536   outstanding, so no context, this one included, can assign it
537   afterwards. Its cancelled operations still complete normally. 537   afterwards. Its cancelled operations still complete normally.
538   538  
539   @return The error code and the native handle. 539   @return The error code and the native handle.
540   540  
541   @post is_open() == false 541   @post is_open() == false
542   */ 542   */
543   [[nodiscard]] capy::results<native_handle_type> release() noexcept; 543   [[nodiscard]] capy::results<native_handle_type> release() noexcept;
544   544  
545   /** Get the local endpoint of the acceptor. 545   /** Get the local endpoint of the acceptor.
546   546  
547   Returns the local address and port to which the acceptor is bound. 547   Returns the local address and port to which the acceptor is bound.
548   This is useful when binding to port 0 (ephemeral port) to discover 548   This is useful when binding to port 0 (ephemeral port) to discover
549   the OS-assigned port number. The endpoint is cached when bind() 549   the OS-assigned port number. The endpoint is cached when bind()
550   is called. 550   is called.
551   551  
552   @return The local endpoint, or a default endpoint (0.0.0.0:0) if 552   @return The local endpoint, or a default endpoint (0.0.0.0:0) if
553   the acceptor is not open. 553   the acceptor is not open.
554   554  
555   @par Thread Safety 555   @par Thread Safety
556   The cached endpoint value is set during bind() and cleared 556   The cached endpoint value is set during bind() and cleared
557   during close(). This function may be called concurrently with 557   during close(). This function may be called concurrently with
558   accept operations, but must not be called concurrently with 558   accept operations, but must not be called concurrently with
559   bind() or close(). 559   bind() or close().
560   */ 560   */
561   endpoint local_endpoint() const noexcept; 561   endpoint local_endpoint() const noexcept;
562   562  
563   /** Set a socket option on the acceptor. 563   /** Set a socket option on the acceptor.
564   564  
565   Applies a type-safe socket option to the underlying listening 565   Applies a type-safe socket option to the underlying listening
566   socket. The socket must be open (via `open()` or `listen()`). 566   socket. The socket must be open (via `open()` or `listen()`).
567   This is useful for setting options between `open()` and 567   This is useful for setting options between `open()` and
568   `listen()`, such as `socket_option::reuse_port`. 568   `listen()`, such as `socket_option::reuse_port`.
569   569  
570   Fails with `errc::bad_file_descriptor` if the acceptor is not 570   Fails with `errc::bad_file_descriptor` if the acceptor is not
571   open, or with the error the operating system reports. 571   open, or with the error the operating system reports.
572   572  
573   @par Example 573   @par Example
574   @par !example set_option 574   @par !example set_option
575   575  
576   @param opt The option to set. 576   @param opt The option to set.
577   577  
578   @return The error code, empty on success. 578   @return The error code, empty on success.
579   */ 579   */
580   template<class Option> 580   template<class Option>
HITCBC 581   1430 [[nodiscard]] std::error_code set_option(Option const& opt) noexcept 581   1430 [[nodiscard]] std::error_code set_option(Option const& opt) noexcept
582   { 582   {
HITCBC 583   1430 if (!is_open()) 583   1430 if (!is_open())
HITCBC 584   2 return make_error_code(std::errc::bad_file_descriptor); 584   2 return make_error_code(std::errc::bad_file_descriptor);
HITCBC 585   1428 auto const fam = get().family(); 585   1428 auto const fam = get().family();
HITCBC 586   1428 return get().set_option( 586   1428 return get().set_option(
HITCBC 587   1428 opt.level(fam), opt.name(fam), opt.data(fam), opt.size(fam)); 587   1428 opt.level(fam), opt.name(fam), opt.data(fam), opt.size(fam));
588   } 588   }
589   589  
590   /** Get a socket option from the acceptor. 590   /** Get a socket option from the acceptor.
591   591  
592   Retrieves the current value of a type-safe socket option. 592   Retrieves the current value of a type-safe socket option.
593   593  
594   Fails with `errc::bad_file_descriptor` if the acceptor is not 594   Fails with `errc::bad_file_descriptor` if the acceptor is not
595   open, or with the error the operating system reports. On 595   open, or with the error the operating system reports. On
596   failure the option is value-initialized. 596   failure the option is value-initialized.
597   597  
598   @par Example 598   @par Example
599   @par !example get_option 599   @par !example get_option
600   600  
601   @return The error code and the option value. 601   @return The error code and the option value.
602   */ 602   */
603   template<class Option> 603   template<class Option>
HITCBC 604   23 [[nodiscard]] capy::results<Option> get_option() const noexcept 604   23 [[nodiscard]] capy::results<Option> get_option() const noexcept
605   { 605   {
HITCBC 606   23 if (!is_open()) 606   23 if (!is_open())
HITCBC 607   2 return {make_error_code(std::errc::bad_file_descriptor), Option{}}; 607   2 return {make_error_code(std::errc::bad_file_descriptor), Option{}};
HITCBC 608   21 Option opt{}; 608   21 Option opt{};
HITCBC 609   21 auto const fam = get().family(); 609   21 auto const fam = get().family();
HITCBC 610   21 std::size_t sz = opt.size(fam); 610   21 std::size_t sz = opt.size(fam);
HITCBC 611   21 if (auto ec = get().get_option( 611   21 if (auto ec = get().get_option(
612   opt.level(fam), opt.name(fam), opt.data(fam), &sz)) 612   opt.level(fam), opt.name(fam), opt.data(fam), &sz))
HITCBC 613   8 return {ec, Option{}}; 613   8 return {ec, Option{}};
HITCBC 614   13 opt.resize(fam, sz); 614   13 opt.resize(fam, sz);
HITCBC 615   13 return {std::error_code{}, std::move(opt)}; 615   13 return {std::error_code{}, std::move(opt)};
616   } 616   }
617   617  
618   /** Define backend hooks for TCP acceptor operations. 618   /** Define backend hooks for TCP acceptor operations.
619   619  
620   Platform backends derive from this to implement 620   Platform backends derive from this to implement
621   accept, endpoint query, open-state checks, cancellation, 621   accept, endpoint query, open-state checks, cancellation,
622   and socket-option management. 622   and socket-option management.
623   */ 623   */
624   struct implementation : io_object::implementation 624   struct implementation : io_object::implementation
625   { 625   {
626   /** Initiate an asynchronous accept operation. 626   /** Initiate an asynchronous accept operation.
627   627  
628   @param cont Continuation to resume on completion; it lives in 628   @param cont Continuation to resume on completion; it lives in
629   the awaiting frame until then. 629   the awaiting frame until then.
630   @param ex Executor for dispatching the completion. 630   @param ex Executor for dispatching the completion.
631   @param token Stop token for cancellation. 631   @param token Stop token for cancellation.
632   @param ec Output error code. 632   @param ec Output error code.
633   @param impl_out Output implementation for the accepted peer. 633   @param impl_out Output implementation for the accepted peer.
634   634  
635   @return Coroutine handle to resume immediately. 635   @return Coroutine handle to resume immediately.
636   */ 636   */
637   virtual std::coroutine_handle<> accept( 637   virtual std::coroutine_handle<> accept(
638   capy::continuation& cont, 638   capy::continuation& cont,
639   capy::executor_ref ex, 639   capy::executor_ref ex,
640   std::stop_token token, 640   std::stop_token token,
641   std::error_code* ec, 641   std::error_code* ec,
642   io_object::implementation** impl_out) = 0; 642   io_object::implementation** impl_out) = 0;
643   643  
644   /** Initiate an asynchronous wait for acceptor readiness. 644   /** Initiate an asynchronous wait for acceptor readiness.
645   645  
646   Completes when the listen socket becomes ready for 646   Completes when the listen socket becomes ready for
647   the specified direction (typically `wait_type::read` 647   the specified direction (typically `wait_type::read`
648   for an incoming connection), or an error condition is 648   for an incoming connection), or an error condition is
649   reported. No connection is consumed. 649   reported. No connection is consumed.
650   650  
651   @param cont Continuation to resume on completion; it lives in 651   @param cont Continuation to resume on completion; it lives in
652   the awaiting frame until then. 652   the awaiting frame until then.
653   @param ex Executor for dispatching the completion. 653   @param ex Executor for dispatching the completion.
654   @param w The direction to wait on. 654   @param w The direction to wait on.
655   @param token Stop token for cancellation. 655   @param token Stop token for cancellation.
656   @param ec Output error code. 656   @param ec Output error code.
657   657  
658   @return Coroutine handle to resume immediately. 658   @return Coroutine handle to resume immediately.
659   */ 659   */
660   virtual std::coroutine_handle<> wait( 660   virtual std::coroutine_handle<> wait(
661   capy::continuation& cont, 661   capy::continuation& cont,
662   capy::executor_ref ex, 662   capy::executor_ref ex,
663   wait_type w, 663   wait_type w,
664   std::stop_token token, 664   std::stop_token token,
665   std::error_code* ec) = 0; 665   std::error_code* ec) = 0;
666   666  
667   /** Returns the cached local endpoint. 667   /** Returns the cached local endpoint.
668   668  
669   @return The cached local endpoint. 669   @return The cached local endpoint.
670   */ 670   */
671   virtual endpoint local_endpoint() const noexcept = 0; 671   virtual endpoint local_endpoint() const noexcept = 0;
672   672  
673   /** Return true if the acceptor has a kernel resource open. 673   /** Return true if the acceptor has a kernel resource open.
674   674  
675   @return true if the acceptor has a kernel resource open. 675   @return true if the acceptor has a kernel resource open.
676   */ 676   */
677   virtual bool is_open() const noexcept = 0; 677   virtual bool is_open() const noexcept = 0;
678   678  
679   /** Return the native handle, or the platform sentinel if closed. 679   /** Return the native handle, or the platform sentinel if closed.
680   680  
681   @return The native handle, or the platform sentinel if closed. 681   @return The native handle, or the platform sentinel if closed.
682   */ 682   */
683   virtual native_handle_type native_handle() const noexcept = 0; 683   virtual native_handle_type native_handle() const noexcept = 0;
684   684  
685   /** Return the socket's address family. 685   /** Return the socket's address family.
686   686  
687   Socket options render for this family. 687   Socket options render for this family.
688   688  
689   @return The socket's address family. 689   @return The socket's address family.
690   */ 690   */
691   virtual corosio::family family() const noexcept = 0; 691   virtual corosio::family family() const noexcept = 0;
692   692  
693   /** Release and return the native handle without closing. 693   /** Release and return the native handle without closing.
694   694  
695   @return The native handle. 695   @return The native handle.
696   */ 696   */
697   virtual native_handle_type release_socket() noexcept = 0; 697   virtual native_handle_type release_socket() noexcept = 0;
698   698  
699   /** Cancel any pending asynchronous operations. 699   /** Cancel any pending asynchronous operations.
700   700  
701   Accept and wait transfer no bytes, so a cancellation always 701   Accept and wait transfer no bytes, so a cancellation always
702   wins: an operation reports `operation_canceled` even when it 702   wins: an operation reports `operation_canceled` even when it
703   had already succeeded when the cancellation landed. 703   had already succeeded when the cancellation landed.
704   */ 704   */
705   virtual void cancel() noexcept = 0; 705   virtual void cancel() noexcept = 0;
706   706  
707   /** Set a socket option. 707   /** Set a socket option.
708   708  
709   @param level The protocol level. 709   @param level The protocol level.
710   @param optname The option name. 710   @param optname The option name.
711   @param data Pointer to the option value. 711   @param data Pointer to the option value.
712   @param size Size of the option value in bytes. 712   @param size Size of the option value in bytes.
713   @return Error code on failure, empty on success. 713   @return Error code on failure, empty on success.
714   */ 714   */
715   virtual std::error_code set_option( 715   virtual std::error_code set_option(
716   int level, 716   int level,
717   int optname, 717   int optname,
718   void const* data, 718   void const* data,
719   std::size_t size) noexcept = 0; 719   std::size_t size) noexcept = 0;
720   720  
721   /** Get a socket option. 721   /** Get a socket option.
722   722  
723   @param level The protocol level. 723   @param level The protocol level.
724   @param optname The option name. 724   @param optname The option name.
725   @param data Pointer to receive the option value. 725   @param data Pointer to receive the option value.
726   @param size On entry, the size of the buffer. On exit, 726   @param size On entry, the size of the buffer. On exit,
727   the size of the option value. 727   the size of the option value.
728   @return Error code on failure, empty on success. 728   @return Error code on failure, empty on success.
729   */ 729   */
730   virtual std::error_code 730   virtual std::error_code
731   get_option(int level, int optname, void* data, std::size_t* size) 731   get_option(int level, int optname, void* data, std::size_t* size)
732   const noexcept = 0; 732   const noexcept = 0;
733   }; 733   };
734   734  
735   protected: 735   protected:
736   /** Adopt an existing handle. 736   /** Adopt an existing handle.
737   737  
738   @param h The handle the acceptor takes ownership of. 738   @param h The handle the acceptor takes ownership of.
739   */ 739   */
HITCBC 740   47 explicit tcp_acceptor(handle h) noexcept : io_object(std::move(h)) {} 740   47 explicit tcp_acceptor(handle h) noexcept : io_object(std::move(h)) {}
741   741  
742   /** Adopt an existing handle, then open, configure, bind, and listen. 742   /** Adopt an existing handle, then open, configure, bind, and listen.
743   743  
744   Lets a derived acceptor offer the convenience constructor while 744   Lets a derived acceptor offer the convenience constructor while
745   supplying its own service. 745   supplying its own service.
746   746  
747   @param h The handle the acceptor takes ownership of. 747   @param h The handle the acceptor takes ownership of.
748   @param ep The local endpoint to bind to. 748   @param ep The local endpoint to bind to.
749   @param backlog The maximum pending connection queue length. 749   @param backlog The maximum pending connection queue length.
750   750  
751   @throws std::system_error on open, configuration, bind, or 751   @throws std::system_error on open, configuration, bind, or
752   listen failure. 752   listen failure.
753   */ 753   */
754   tcp_acceptor(handle h, endpoint ep, int backlog); 754   tcp_acceptor(handle h, endpoint ep, int backlog);
755   755  
756   /** Transfer the accepted peer implementation to the peer socket. 756   /** Transfer the accepted peer implementation to the peer socket.
757   757  
758   @param peer The socket that receives the transferred implementation. 758   @param peer The socket that receives the transferred implementation.
759   @param impl The accepted peer implementation, or null to do nothing. 759   @param impl The accepted peer implementation, or null to do nothing.
760   */ 760   */
761   static void 761   static void
HITCBC 762   15 reset_peer_impl(tcp_socket& peer, io_object::implementation* impl) noexcept 762   15 reset_peer_impl(tcp_socket& peer, io_object::implementation* impl) noexcept
763   { 763   {
HITCBC 764   15 if (impl) 764   15 if (impl)
HITCBC 765   15 peer.h_.reset(impl); 765   15 peer.h_.reset(impl);
HITCBC 766   15 } 766   15 }
767   767  
768   /** Return the result of an accept that yields the peer. 768   /** Return the result of an accept that yields the peer.
769   769  
770   The peer socket is built only on success, so a failed accept 770   The peer socket is built only on success, so a failed accept
771   never touches the acceptor's context, which a moved-from 771   never touches the acceptor's context, which a moved-from
772   acceptor lacks. On failure the peer is default-constructed. 772   acceptor lacks. On failure the peer is default-constructed.
773   773  
774   @param acc The acceptor that performed the accept. 774   @param acc The acceptor that performed the accept.
775   @param ec The completion code. 775   @param ec The completion code.
776   @param impl The accepted peer implementation; taken on success. 776   @param impl The accepted peer implementation; taken on success.
777   777  
778   @return The completion code and the peer. 778   @return The completion code and the peer.
779   */ 779   */
HITCBC 780   39 static capy::results<tcp_socket> take_peer( 780   39 static capy::results<tcp_socket> take_peer(
781   tcp_acceptor& acc, 781   tcp_acceptor& acc,
782   std::error_code ec, 782   std::error_code ec,
783   io_object::implementation*& impl) noexcept 783   io_object::implementation*& impl) noexcept
784   { 784   {
HITCBC 785   39 if (ec || !impl) 785   39 if (ec || !impl)
HITCBC 786   12 return {ec, tcp_socket()}; 786   12 return {ec, tcp_socket()};
787   787  
HITCBC 788   27 tcp_socket peer(acc.context()); 788   27 tcp_socket peer(acc.context());
HITCBC 789   27 peer.h_.reset(std::exchange(impl, nullptr)); 789   27 peer.h_.reset(std::exchange(impl, nullptr));
HITCBC 790   27 return {ec, std::move(peer)}; 790   27 return {ec, std::move(peer)};
HITCBC 791   27 } 791   27 }
792   792  
793   /// Close and release a non-null accepted peer no socket took over. 793   /// Close and release a non-null accepted peer no socket took over.
794   static void 794   static void
795   discard_peer(tcp_acceptor& acc, io_object::implementation* impl) noexcept; 795   discard_peer(tcp_acceptor& acc, io_object::implementation* impl) noexcept;
796   796  
797   private: 797   private:
HITCBC 798   32374 inline implementation& get() const noexcept 798   32751 inline implementation& get() const noexcept
799   { 799   {
HITCBC 800   32374 return *static_cast<implementation*>(h_.get()); 800   32751 return *static_cast<implementation*>(h_.get());
801   } 801   }
802   }; 802   };
803   803  
804   } // namespace boost::corosio 804   } // namespace boost::corosio
805   805  
806   #endif 806   #endif