1 | // |
2 | // posix/basic_stream_descriptor.hpp |
3 | // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
4 | // |
5 | // Copyright (c) 2003-2024 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
6 | // |
7 | // Distributed under the Boost Software License, Version 1.0. (See accompanying |
8 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
9 | // |
10 | |
11 | #ifndef BOOST_ASIO_POSIX_BASIC_STREAM_DESCRIPTOR_HPP |
12 | #define BOOST_ASIO_POSIX_BASIC_STREAM_DESCRIPTOR_HPP |
13 | |
14 | #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
15 | # pragma once |
16 | #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
17 | |
18 | #include <boost/asio/detail/config.hpp> |
19 | #include <boost/asio/posix/basic_descriptor.hpp> |
20 | |
21 | #if defined(BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR) \ |
22 | || defined(GENERATING_DOCUMENTATION) |
23 | |
24 | #include <boost/asio/detail/push_options.hpp> |
25 | |
26 | namespace boost { |
27 | namespace asio { |
28 | namespace posix { |
29 | |
30 | /// Provides stream-oriented descriptor functionality. |
31 | /** |
32 | * The posix::basic_stream_descriptor class template provides asynchronous and |
33 | * blocking stream-oriented descriptor functionality. |
34 | * |
35 | * @par Thread Safety |
36 | * @e Distinct @e objects: Safe.@n |
37 | * @e Shared @e objects: Unsafe. |
38 | * |
39 | * Synchronous @c read_some and @c write_some operations are thread safe with |
40 | * respect to each other, if the underlying operating system calls are also |
41 | * thread safe. This means that it is permitted to perform concurrent calls to |
42 | * these synchronous operations on a single descriptor object. Other synchronous |
43 | * operations, such as @c close, are not thread safe. |
44 | * |
45 | * @par Concepts: |
46 | * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream. |
47 | */ |
48 | template <typename Executor = any_io_executor> |
49 | class basic_stream_descriptor |
50 | : public basic_descriptor<Executor> |
51 | { |
52 | private: |
53 | class initiate_async_write_some; |
54 | class initiate_async_read_some; |
55 | |
56 | public: |
57 | /// The type of the executor associated with the object. |
58 | typedef Executor executor_type; |
59 | |
60 | /// Rebinds the descriptor type to another executor. |
61 | template <typename Executor1> |
62 | struct rebind_executor |
63 | { |
64 | /// The descriptor type when rebound to the specified executor. |
65 | typedef basic_stream_descriptor<Executor1> other; |
66 | }; |
67 | |
68 | /// The native representation of a descriptor. |
69 | typedef typename basic_descriptor<Executor>::native_handle_type |
70 | native_handle_type; |
71 | |
72 | /// Construct a stream descriptor without opening it. |
73 | /** |
74 | * This constructor creates a stream descriptor without opening it. The |
75 | * descriptor needs to be opened and then connected or accepted before data |
76 | * can be sent or received on it. |
77 | * |
78 | * @param ex The I/O executor that the descriptor will use, by default, to |
79 | * dispatch handlers for any asynchronous operations performed on the |
80 | * descriptor. |
81 | */ |
82 | explicit basic_stream_descriptor(const executor_type& ex) |
83 | : basic_descriptor<Executor>(ex) |
84 | { |
85 | } |
86 | |
87 | /// Construct a stream descriptor without opening it. |
88 | /** |
89 | * This constructor creates a stream descriptor without opening it. The |
90 | * descriptor needs to be opened and then connected or accepted before data |
91 | * can be sent or received on it. |
92 | * |
93 | * @param context An execution context which provides the I/O executor that |
94 | * the descriptor will use, by default, to dispatch handlers for any |
95 | * asynchronous operations performed on the descriptor. |
96 | */ |
97 | template <typename ExecutionContext> |
98 | explicit basic_stream_descriptor(ExecutionContext& context, |
99 | constraint_t< |
100 | is_convertible<ExecutionContext&, execution_context&>::value, |
101 | defaulted_constraint |
102 | > = defaulted_constraint()) |
103 | : basic_descriptor<Executor>(context) |
104 | { |
105 | } |
106 | |
107 | /// Construct a stream descriptor on an existing native descriptor. |
108 | /** |
109 | * This constructor creates a stream descriptor object to hold an existing |
110 | * native descriptor. |
111 | * |
112 | * @param ex The I/O executor that the descriptor will use, by default, to |
113 | * dispatch handlers for any asynchronous operations performed on the |
114 | * descriptor. |
115 | * |
116 | * @param native_descriptor The new underlying descriptor implementation. |
117 | * |
118 | * @throws boost::system::system_error Thrown on failure. |
119 | */ |
120 | basic_stream_descriptor(const executor_type& ex, |
121 | const native_handle_type& native_descriptor) |
122 | : basic_descriptor<Executor>(ex, native_descriptor) |
123 | { |
124 | } |
125 | |
126 | /// Construct a stream descriptor on an existing native descriptor. |
127 | /** |
128 | * This constructor creates a stream descriptor object to hold an existing |
129 | * native descriptor. |
130 | * |
131 | * @param context An execution context which provides the I/O executor that |
132 | * the descriptor will use, by default, to dispatch handlers for any |
133 | * asynchronous operations performed on the descriptor. |
134 | * |
135 | * @param native_descriptor The new underlying descriptor implementation. |
136 | * |
137 | * @throws boost::system::system_error Thrown on failure. |
138 | */ |
139 | template <typename ExecutionContext> |
140 | basic_stream_descriptor(ExecutionContext& context, |
141 | const native_handle_type& native_descriptor, |
142 | constraint_t< |
143 | is_convertible<ExecutionContext&, execution_context&>::value |
144 | > = 0) |
145 | : basic_descriptor<Executor>(context, native_descriptor) |
146 | { |
147 | } |
148 | |
149 | /// Move-construct a stream descriptor from another. |
150 | /** |
151 | * This constructor moves a stream descriptor from one object to another. |
152 | * |
153 | * @param other The other stream descriptor object from which the move |
154 | * will occur. |
155 | * |
156 | * @note Following the move, the moved-from object is in the same state as if |
157 | * constructed using the @c basic_stream_descriptor(const executor_type&) |
158 | * constructor. |
159 | */ |
160 | basic_stream_descriptor(basic_stream_descriptor&& other) noexcept |
161 | : basic_descriptor<Executor>(std::move(other)) |
162 | { |
163 | } |
164 | |
165 | /// Move-assign a stream descriptor from another. |
166 | /** |
167 | * This assignment operator moves a stream descriptor from one object to |
168 | * another. |
169 | * |
170 | * @param other The other stream descriptor object from which the move |
171 | * will occur. |
172 | * |
173 | * @note Following the move, the moved-from object is in the same state as if |
174 | * constructed using the @c basic_stream_descriptor(const executor_type&) |
175 | * constructor. |
176 | */ |
177 | basic_stream_descriptor& operator=(basic_stream_descriptor&& other) |
178 | { |
179 | basic_descriptor<Executor>::operator=(std::move(other)); |
180 | return *this; |
181 | } |
182 | |
183 | /// Move-construct a basic_stream_descriptor from a descriptor of another |
184 | /// executor type. |
185 | /** |
186 | * This constructor moves a descriptor from one object to another. |
187 | * |
188 | * @param other The other basic_stream_descriptor object from which the move |
189 | * will occur. |
190 | * |
191 | * @note Following the move, the moved-from object is in the same state as if |
192 | * constructed using the @c basic_stream_descriptor(const executor_type&) |
193 | * constructor. |
194 | */ |
195 | template <typename Executor1> |
196 | basic_stream_descriptor(basic_stream_descriptor<Executor1>&& other, |
197 | constraint_t< |
198 | is_convertible<Executor1, Executor>::value, |
199 | defaulted_constraint |
200 | > = defaulted_constraint()) |
201 | : basic_descriptor<Executor>(std::move(other)) |
202 | { |
203 | } |
204 | |
205 | /// Move-assign a basic_stream_descriptor from a descriptor of another |
206 | /// executor type. |
207 | /** |
208 | * This assignment operator moves a descriptor from one object to another. |
209 | * |
210 | * @param other The other basic_stream_descriptor object from which the move |
211 | * will occur. |
212 | * |
213 | * @note Following the move, the moved-from object is in the same state as if |
214 | * constructed using the @c basic_stream_descriptor(const executor_type&) |
215 | * constructor. |
216 | */ |
217 | template <typename Executor1> |
218 | constraint_t< |
219 | is_convertible<Executor1, Executor>::value, |
220 | basic_stream_descriptor& |
221 | > operator=(basic_stream_descriptor<Executor1> && other) |
222 | { |
223 | basic_descriptor<Executor>::operator=(std::move(other)); |
224 | return *this; |
225 | } |
226 | |
227 | /// Write some data to the descriptor. |
228 | /** |
229 | * This function is used to write data to the stream descriptor. The function |
230 | * call will block until one or more bytes of the data has been written |
231 | * successfully, or until an error occurs. |
232 | * |
233 | * @param buffers One or more data buffers to be written to the descriptor. |
234 | * |
235 | * @returns The number of bytes written. |
236 | * |
237 | * @throws boost::system::system_error Thrown on failure. An error code of |
238 | * boost::asio::error::eof indicates that the connection was closed by the |
239 | * peer. |
240 | * |
241 | * @note The write_some operation may not transmit all of the data to the |
242 | * peer. Consider using the @ref write function if you need to ensure that |
243 | * all data is written before the blocking operation completes. |
244 | * |
245 | * @par Example |
246 | * To write a single data buffer use the @ref buffer function as follows: |
247 | * @code |
248 | * descriptor.write_some(boost::asio::buffer(data, size)); |
249 | * @endcode |
250 | * See the @ref buffer documentation for information on writing multiple |
251 | * buffers in one go, and how to use it with arrays, boost::array or |
252 | * std::vector. |
253 | */ |
254 | template <typename ConstBufferSequence> |
255 | std::size_t write_some(const ConstBufferSequence& buffers) |
256 | { |
257 | boost::system::error_code ec; |
258 | std::size_t s = this->impl_.get_service().write_some( |
259 | this->impl_.get_implementation(), buffers, ec); |
260 | boost::asio::detail::throw_error(err: ec, location: "write_some" ); |
261 | return s; |
262 | } |
263 | |
264 | /// Write some data to the descriptor. |
265 | /** |
266 | * This function is used to write data to the stream descriptor. The function |
267 | * call will block until one or more bytes of the data has been written |
268 | * successfully, or until an error occurs. |
269 | * |
270 | * @param buffers One or more data buffers to be written to the descriptor. |
271 | * |
272 | * @param ec Set to indicate what error occurred, if any. |
273 | * |
274 | * @returns The number of bytes written. Returns 0 if an error occurred. |
275 | * |
276 | * @note The write_some operation may not transmit all of the data to the |
277 | * peer. Consider using the @ref write function if you need to ensure that |
278 | * all data is written before the blocking operation completes. |
279 | */ |
280 | template <typename ConstBufferSequence> |
281 | std::size_t write_some(const ConstBufferSequence& buffers, |
282 | boost::system::error_code& ec) |
283 | { |
284 | return this->impl_.get_service().write_some( |
285 | this->impl_.get_implementation(), buffers, ec); |
286 | } |
287 | |
288 | /// Start an asynchronous write. |
289 | /** |
290 | * This function is used to asynchronously write data to the stream |
291 | * descriptor. It is an initiating function for an @ref |
292 | * asynchronous_operation, and always returns immediately. |
293 | * |
294 | * @param buffers One or more data buffers to be written to the descriptor. |
295 | * Although the buffers object may be copied as necessary, ownership of the |
296 | * underlying memory blocks is retained by the caller, which must guarantee |
297 | * that they remain valid until the completion handler is called. |
298 | * |
299 | * @param token The @ref completion_token that will be used to produce a |
300 | * completion handler, which will be called when the write completes. |
301 | * Potential completion tokens include @ref use_future, @ref use_awaitable, |
302 | * @ref yield_context, or a function object with the correct completion |
303 | * signature. The function signature of the completion handler must be: |
304 | * @code void handler( |
305 | * const boost::system::error_code& error, // Result of operation. |
306 | * std::size_t bytes_transferred // Number of bytes written. |
307 | * ); @endcode |
308 | * Regardless of whether the asynchronous operation completes immediately or |
309 | * not, the completion handler will not be invoked from within this function. |
310 | * On immediate completion, invocation of the handler will be performed in a |
311 | * manner equivalent to using boost::asio::post(). |
312 | * |
313 | * @par Completion Signature |
314 | * @code void(boost::system::error_code, std::size_t) @endcode |
315 | * |
316 | * @note The write operation may not transmit all of the data to the peer. |
317 | * Consider using the @ref async_write function if you need to ensure that all |
318 | * data is written before the asynchronous operation completes. |
319 | * |
320 | * @par Example |
321 | * To write a single data buffer use the @ref buffer function as follows: |
322 | * @code |
323 | * descriptor.async_write_some(boost::asio::buffer(data, size), handler); |
324 | * @endcode |
325 | * See the @ref buffer documentation for information on writing multiple |
326 | * buffers in one go, and how to use it with arrays, boost::array or |
327 | * std::vector. |
328 | * |
329 | * @par Per-Operation Cancellation |
330 | * This asynchronous operation supports cancellation for the following |
331 | * boost::asio::cancellation_type values: |
332 | * |
333 | * @li @c cancellation_type::terminal |
334 | * |
335 | * @li @c cancellation_type::partial |
336 | * |
337 | * @li @c cancellation_type::total |
338 | */ |
339 | template <typename ConstBufferSequence, |
340 | BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, |
341 | std::size_t)) WriteToken = default_completion_token_t<executor_type>> |
342 | auto async_write_some(const ConstBufferSequence& buffers, |
343 | WriteToken&& token = default_completion_token_t<executor_type>()) |
344 | -> decltype( |
345 | async_initiate<WriteToken, |
346 | void (boost::system::error_code, std::size_t)>( |
347 | initiate_async_write_some(this), token, buffers)) |
348 | { |
349 | return async_initiate<WriteToken, |
350 | void (boost::system::error_code, std::size_t)>( |
351 | initiate_async_write_some(this), token, buffers); |
352 | } |
353 | |
354 | /// Read some data from the descriptor. |
355 | /** |
356 | * This function is used to read data from the stream descriptor. The function |
357 | * call will block until one or more bytes of data has been read successfully, |
358 | * or until an error occurs. |
359 | * |
360 | * @param buffers One or more buffers into which the data will be read. |
361 | * |
362 | * @returns The number of bytes read. |
363 | * |
364 | * @throws boost::system::system_error Thrown on failure. An error code of |
365 | * boost::asio::error::eof indicates that the connection was closed by the |
366 | * peer. |
367 | * |
368 | * @note The read_some operation may not read all of the requested number of |
369 | * bytes. Consider using the @ref read function if you need to ensure that |
370 | * the requested amount of data is read before the blocking operation |
371 | * completes. |
372 | * |
373 | * @par Example |
374 | * To read into a single data buffer use the @ref buffer function as follows: |
375 | * @code |
376 | * descriptor.read_some(boost::asio::buffer(data, size)); |
377 | * @endcode |
378 | * See the @ref buffer documentation for information on reading into multiple |
379 | * buffers in one go, and how to use it with arrays, boost::array or |
380 | * std::vector. |
381 | */ |
382 | template <typename MutableBufferSequence> |
383 | std::size_t read_some(const MutableBufferSequence& buffers) |
384 | { |
385 | boost::system::error_code ec; |
386 | std::size_t s = this->impl_.get_service().read_some( |
387 | this->impl_.get_implementation(), buffers, ec); |
388 | boost::asio::detail::throw_error(err: ec, location: "read_some" ); |
389 | return s; |
390 | } |
391 | |
392 | /// Read some data from the descriptor. |
393 | /** |
394 | * This function is used to read data from the stream descriptor. The function |
395 | * call will block until one or more bytes of data has been read successfully, |
396 | * or until an error occurs. |
397 | * |
398 | * @param buffers One or more buffers into which the data will be read. |
399 | * |
400 | * @param ec Set to indicate what error occurred, if any. |
401 | * |
402 | * @returns The number of bytes read. Returns 0 if an error occurred. |
403 | * |
404 | * @note The read_some operation may not read all of the requested number of |
405 | * bytes. Consider using the @ref read function if you need to ensure that |
406 | * the requested amount of data is read before the blocking operation |
407 | * completes. |
408 | */ |
409 | template <typename MutableBufferSequence> |
410 | std::size_t read_some(const MutableBufferSequence& buffers, |
411 | boost::system::error_code& ec) |
412 | { |
413 | return this->impl_.get_service().read_some( |
414 | this->impl_.get_implementation(), buffers, ec); |
415 | } |
416 | |
417 | /// Start an asynchronous read. |
418 | /** |
419 | * This function is used to asynchronously read data from the stream |
420 | * descriptor. It is an initiating function for an @ref |
421 | * asynchronous_operation, and always returns immediately. |
422 | * |
423 | * @param buffers One or more buffers into which the data will be read. |
424 | * Although the buffers object may be copied as necessary, ownership of the |
425 | * underlying memory blocks is retained by the caller, which must guarantee |
426 | * that they remain valid until the completion handler is called. |
427 | * |
428 | * @param token The @ref completion_token that will be used to produce a |
429 | * completion handler, which will be called when the read completes. |
430 | * Potential completion tokens include @ref use_future, @ref use_awaitable, |
431 | * @ref yield_context, or a function object with the correct completion |
432 | * signature. The function signature of the completion handler must be: |
433 | * @code void handler( |
434 | * const boost::system::error_code& error, // Result of operation. |
435 | * std::size_t bytes_transferred // Number of bytes read. |
436 | * ); @endcode |
437 | * Regardless of whether the asynchronous operation completes immediately or |
438 | * not, the completion handler will not be invoked from within this function. |
439 | * On immediate completion, invocation of the handler will be performed in a |
440 | * manner equivalent to using boost::asio::post(). |
441 | * |
442 | * @par Completion Signature |
443 | * @code void(boost::system::error_code, std::size_t) @endcode |
444 | * |
445 | * @note The read operation may not read all of the requested number of bytes. |
446 | * Consider using the @ref async_read function if you need to ensure that the |
447 | * requested amount of data is read before the asynchronous operation |
448 | * completes. |
449 | * |
450 | * @par Example |
451 | * To read into a single data buffer use the @ref buffer function as follows: |
452 | * @code |
453 | * descriptor.async_read_some(boost::asio::buffer(data, size), handler); |
454 | * @endcode |
455 | * See the @ref buffer documentation for information on reading into multiple |
456 | * buffers in one go, and how to use it with arrays, boost::array or |
457 | * std::vector. |
458 | * |
459 | * @par Per-Operation Cancellation |
460 | * This asynchronous operation supports cancellation for the following |
461 | * boost::asio::cancellation_type values: |
462 | * |
463 | * @li @c cancellation_type::terminal |
464 | * |
465 | * @li @c cancellation_type::partial |
466 | * |
467 | * @li @c cancellation_type::total |
468 | */ |
469 | template <typename MutableBufferSequence, |
470 | BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, |
471 | std::size_t)) ReadToken = default_completion_token_t<executor_type>> |
472 | auto async_read_some(const MutableBufferSequence& buffers, |
473 | ReadToken&& token = default_completion_token_t<executor_type>()) |
474 | -> decltype( |
475 | async_initiate<ReadToken, |
476 | void (boost::system::error_code, std::size_t)>( |
477 | declval<initiate_async_read_some>(), token, buffers)) |
478 | { |
479 | return async_initiate<ReadToken, |
480 | void (boost::system::error_code, std::size_t)>( |
481 | initiate_async_read_some(this), token, buffers); |
482 | } |
483 | |
484 | private: |
485 | class initiate_async_write_some |
486 | { |
487 | public: |
488 | typedef Executor executor_type; |
489 | |
490 | explicit initiate_async_write_some(basic_stream_descriptor* self) |
491 | : self_(self) |
492 | { |
493 | } |
494 | |
495 | const executor_type& get_executor() const noexcept |
496 | { |
497 | return self_->get_executor(); |
498 | } |
499 | |
500 | template <typename WriteHandler, typename ConstBufferSequence> |
501 | void operator()(WriteHandler&& handler, |
502 | const ConstBufferSequence& buffers) const |
503 | { |
504 | // If you get an error on the following line it means that your handler |
505 | // does not meet the documented type requirements for a WriteHandler. |
506 | BOOST_ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check; |
507 | |
508 | detail::non_const_lvalue<WriteHandler> handler2(handler); |
509 | self_->impl_.get_service().async_write_some( |
510 | self_->impl_.get_implementation(), buffers, |
511 | handler2.value, self_->impl_.get_executor()); |
512 | } |
513 | |
514 | private: |
515 | basic_stream_descriptor* self_; |
516 | }; |
517 | |
518 | class initiate_async_read_some |
519 | { |
520 | public: |
521 | typedef Executor executor_type; |
522 | |
523 | explicit initiate_async_read_some(basic_stream_descriptor* self) |
524 | : self_(self) |
525 | { |
526 | } |
527 | |
528 | const executor_type& get_executor() const noexcept |
529 | { |
530 | return self_->get_executor(); |
531 | } |
532 | |
533 | template <typename ReadHandler, typename MutableBufferSequence> |
534 | void operator()(ReadHandler&& handler, |
535 | const MutableBufferSequence& buffers) const |
536 | { |
537 | // If you get an error on the following line it means that your handler |
538 | // does not meet the documented type requirements for a ReadHandler. |
539 | BOOST_ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check; |
540 | |
541 | detail::non_const_lvalue<ReadHandler> handler2(handler); |
542 | self_->impl_.get_service().async_read_some( |
543 | self_->impl_.get_implementation(), buffers, |
544 | handler2.value, self_->impl_.get_executor()); |
545 | } |
546 | |
547 | private: |
548 | basic_stream_descriptor* self_; |
549 | }; |
550 | }; |
551 | |
552 | } // namespace posix |
553 | } // namespace asio |
554 | } // namespace boost |
555 | |
556 | #include <boost/asio/detail/pop_options.hpp> |
557 | |
558 | #endif // defined(BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR) |
559 | // || defined(GENERATING_DOCUMENTATION) |
560 | |
561 | #endif // BOOST_ASIO_POSIX_BASIC_STREAM_DESCRIPTOR_HPP |
562 | |