1 //
2 // impl/compose.hpp
3 // ~~~~~~~~~~~~~~~~
4 //
5 // Copyright (c) 2003-2019 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 ASIO_IMPL_COMPOSE_HPP
12 #define ASIO_IMPL_COMPOSE_HPP
13
14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
15 # pragma once
16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
17
18 #include "asio/detail/config.hpp"
19 #include "asio/detail/handler_alloc_helpers.hpp"
20 #include "asio/detail/handler_cont_helpers.hpp"
21 #include "asio/detail/handler_invoke_helpers.hpp"
22 #include "asio/detail/type_traits.hpp"
23 #include "asio/detail/variadic_templates.hpp"
24 #include "asio/executor_work_guard.hpp"
25 #include "asio/is_executor.hpp"
26 #include "asio/system_executor.hpp"
27
28 #include "asio/detail/push_options.hpp"
29
30 namespace asio {
31
32 namespace detail
33 {
34 template <typename>
35 struct composed_work;
36
37 template <>
38 struct composed_work<void()>
39 {
composed_workasio::detail::composed_work40 composed_work() ASIO_NOEXCEPT
41 : head_(system_executor())
42 {
43 }
44
resetasio::detail::composed_work45 void reset()
46 {
47 head_.reset();
48 }
49
50 typedef system_executor head_type;
51 executor_work_guard<system_executor> head_;
52 };
53
make_composed_work()54 inline composed_work<void()> make_composed_work()
55 {
56 return composed_work<void()>();
57 }
58
59 template <typename Head>
60 struct composed_work<void(Head)>
61 {
composed_workasio::detail::composed_work62 explicit composed_work(const Head& ex) ASIO_NOEXCEPT
63 : head_(ex)
64 {
65 }
66
resetasio::detail::composed_work67 void reset()
68 {
69 head_.reset();
70 }
71
72 typedef Head head_type;
73 executor_work_guard<Head> head_;
74 };
75
76 template <typename Head>
make_composed_work(const Head & head)77 inline composed_work<void(Head)> make_composed_work(const Head& head)
78 {
79 return composed_work<void(Head)>(head);
80 }
81
82 #if defined(ASIO_HAS_VARIADIC_TEMPLATES)
83
84 template <typename Head, typename... Tail>
85 struct composed_work<void(Head, Tail...)>
86 {
composed_workasio::detail::composed_work87 explicit composed_work(const Head& head,
88 const Tail&... tail) ASIO_NOEXCEPT
89 : head_(head),
90 tail_(tail...)
91 {
92 }
93
resetasio::detail::composed_work94 void reset()
95 {
96 head_.reset();
97 tail_.reset();
98 }
99
100 typedef Head head_type;
101 executor_work_guard<Head> head_;
102 composed_work<void(Tail...)> tail_;
103 };
104
105 template <typename Head, typename... Tail>
106 inline composed_work<void(Head, Tail...)>
make_composed_work(const Head & head,const Tail &...tail)107 make_composed_work(const Head& head, const Tail&... tail)
108 {
109 return composed_work<void(Head, Tail...)>(head, tail...);
110 }
111
112 #else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
113
114 #define ASIO_PRIVATE_COMPOSED_WORK_DEF(n) \
115 template <typename Head, ASIO_VARIADIC_TPARAMS(n)> \
116 struct composed_work<void(Head, ASIO_VARIADIC_TARGS(n))> \
117 { \
118 explicit composed_work(const Head& head, \
119 ASIO_VARIADIC_CONSTREF_PARAMS(n)) ASIO_NOEXCEPT \
120 : head_(head), \
121 tail_(ASIO_VARIADIC_BYVAL_ARGS(n)) \
122 { \
123 } \
124 \
125 void reset() \
126 { \
127 head_.reset(); \
128 tail_.reset(); \
129 } \
130 \
131 typedef Head head_type; \
132 executor_work_guard<Head> head_; \
133 composed_work<void(ASIO_VARIADIC_TARGS(n))> tail_; \
134 }; \
135 \
136 template <typename Head, ASIO_VARIADIC_TPARAMS(n)> \
137 inline composed_work<void(Head, ASIO_VARIADIC_TARGS(n))> \
138 make_composed_work(const Head& head, ASIO_VARIADIC_CONSTREF_PARAMS(n)) \
139 { \
140 return composed_work< \
141 void(Head, ASIO_VARIADIC_TARGS(n))>( \
142 head, ASIO_VARIADIC_BYVAL_ARGS(n)); \
143 } \
144 /**/
145 ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_COMPOSED_WORK_DEF)
146 #undef ASIO_PRIVATE_COMPOSED_WORK_DEF
147
148 #endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
149
150 #if defined(ASIO_HAS_VARIADIC_TEMPLATES)
151 template <typename Impl, typename Work, typename Handler, typename Signature>
152 class composed_op;
153
154 template <typename Impl, typename Work, typename Handler,
155 typename R, typename... Args>
156 class composed_op<Impl, Work, Handler, R(Args...)>
157 #else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
158 template <typename Impl, typename Work, typename Handler, typename Signature>
159 class composed_op
160 #endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
161 {
162 public:
composed_op(ASIO_MOVE_ARG (Impl)impl,ASIO_MOVE_ARG (Work)work,ASIO_MOVE_ARG (Handler)handler)163 composed_op(ASIO_MOVE_ARG(Impl) impl,
164 ASIO_MOVE_ARG(Work) work,
165 ASIO_MOVE_ARG(Handler) handler)
166 : impl_(ASIO_MOVE_CAST(Impl)(impl)),
167 work_(ASIO_MOVE_CAST(Work)(work)),
168 handler_(ASIO_MOVE_CAST(Handler)(handler)),
169 invocations_(0)
170 {
171 }
172
173 #if defined(ASIO_HAS_MOVE)
composed_op(composed_op && other)174 composed_op(composed_op&& other)
175 : impl_(ASIO_MOVE_CAST(Impl)(other.impl_)),
176 work_(ASIO_MOVE_CAST(Work)(other.work_)),
177 handler_(ASIO_MOVE_CAST(Handler)(other.handler_)),
178 invocations_(other.invocations_)
179 {
180 }
181 #endif // defined(ASIO_HAS_MOVE)
182
183 typedef typename associated_executor<Handler,
184 typename Work::head_type>::type executor_type;
185
get_executor() const186 executor_type get_executor() const ASIO_NOEXCEPT
187 {
188 return (get_associated_executor)(handler_, work_.head_.get_executor());
189 }
190
191 typedef typename associated_allocator<Handler,
192 std::allocator<void> >::type allocator_type;
193
get_allocator() const194 allocator_type get_allocator() const ASIO_NOEXCEPT
195 {
196 return (get_associated_allocator)(handler_, std::allocator<void>());
197 }
198
199 #if defined(ASIO_HAS_VARIADIC_TEMPLATES)
200
201 template<typename... T>
operator ()(ASIO_MOVE_ARG (T)...t)202 void operator()(ASIO_MOVE_ARG(T)... t)
203 {
204 if (invocations_ < ~unsigned(0))
205 ++invocations_;
206 impl_(*this, ASIO_MOVE_CAST(T)(t)...);
207 }
208
complete(Args...args)209 void complete(Args... args)
210 {
211 this->work_.reset();
212 this->handler_(ASIO_MOVE_CAST(Args)(args)...);
213 }
214
215 #else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
216
operator ()()217 void operator()()
218 {
219 if (invocations_ < ~unsigned(0))
220 ++invocations_;
221 impl_(*this);
222 }
223
complete()224 void complete()
225 {
226 this->work_.reset();
227 this->handler_();
228 }
229
230 #define ASIO_PRIVATE_COMPOSED_OP_DEF(n) \
231 template<ASIO_VARIADIC_TPARAMS(n)> \
232 void operator()(ASIO_VARIADIC_MOVE_PARAMS(n)) \
233 { \
234 if (invocations_ < ~unsigned(0)) \
235 ++invocations_; \
236 impl_(*this, ASIO_VARIADIC_MOVE_ARGS(n)); \
237 } \
238 \
239 template<ASIO_VARIADIC_TPARAMS(n)> \
240 void complete(ASIO_VARIADIC_MOVE_PARAMS(n)) \
241 { \
242 this->work_.reset(); \
243 this->handler_(ASIO_VARIADIC_MOVE_ARGS(n)); \
244 } \
245 /**/
246 ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_COMPOSED_OP_DEF)
247 #undef ASIO_PRIVATE_COMPOSED_OP_DEF
248
249 #endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
250
251 //private:
252 Impl impl_;
253 Work work_;
254 Handler handler_;
255 unsigned invocations_;
256 };
257
258 template <typename Impl, typename Work, typename Handler, typename Signature>
asio_handler_allocate(std::size_t size,composed_op<Impl,Work,Handler,Signature> * this_handler)259 inline void* asio_handler_allocate(std::size_t size,
260 composed_op<Impl, Work, Handler, Signature>* this_handler)
261 {
262 return asio_handler_alloc_helpers::allocate(
263 size, this_handler->handler_);
264 }
265
266 template <typename Impl, typename Work, typename Handler, typename Signature>
asio_handler_deallocate(void * pointer,std::size_t size,composed_op<Impl,Work,Handler,Signature> * this_handler)267 inline void asio_handler_deallocate(void* pointer, std::size_t size,
268 composed_op<Impl, Work, Handler, Signature>* this_handler)
269 {
270 asio_handler_alloc_helpers::deallocate(
271 pointer, size, this_handler->handler_);
272 }
273
274 template <typename Impl, typename Work, typename Handler, typename Signature>
asio_handler_is_continuation(composed_op<Impl,Work,Handler,Signature> * this_handler)275 inline bool asio_handler_is_continuation(
276 composed_op<Impl, Work, Handler, Signature>* this_handler)
277 {
278 return this_handler->invocations_ > 1 ? true
279 : asio_handler_cont_helpers::is_continuation(
280 this_handler->handler_);
281 }
282
283 template <typename Function, typename Impl,
284 typename Work, typename Handler, typename Signature>
asio_handler_invoke(Function & function,composed_op<Impl,Work,Handler,Signature> * this_handler)285 inline void asio_handler_invoke(Function& function,
286 composed_op<Impl, Work, Handler, Signature>* this_handler)
287 {
288 asio_handler_invoke_helpers::invoke(
289 function, this_handler->handler_);
290 }
291
292 template <typename Function, typename Impl,
293 typename Work, typename Handler, typename Signature>
asio_handler_invoke(const Function & function,composed_op<Impl,Work,Handler,Signature> * this_handler)294 inline void asio_handler_invoke(const Function& function,
295 composed_op<Impl, Work, Handler, Signature>* this_handler)
296 {
297 asio_handler_invoke_helpers::invoke(
298 function, this_handler->handler_);
299 }
300
301 template <typename Signature>
302 struct initiate_composed_op
303 {
304 template <typename Handler, typename Impl, typename Work>
operator ()asio::detail::initiate_composed_op305 void operator()(ASIO_MOVE_ARG(Handler) handler,
306 ASIO_MOVE_ARG(Impl) impl,
307 ASIO_MOVE_ARG(Work) work) const
308 {
309 composed_op<typename decay<Impl>::type, typename decay<Work>::type,
310 typename decay<Handler>::type, Signature>(
311 ASIO_MOVE_CAST(Impl)(impl), ASIO_MOVE_CAST(Work)(work),
312 ASIO_MOVE_CAST(Handler)(handler))();
313 }
314 };
315
316 template <typename IoObject>
317 inline typename IoObject::executor_type
get_composed_io_executor(IoObject & io_object)318 get_composed_io_executor(IoObject& io_object)
319 {
320 return io_object.get_executor();
321 }
322
323 template <typename Executor>
get_composed_io_executor(const Executor & ex,typename enable_if<is_executor<Executor>::value>::type * =0)324 inline const Executor& get_composed_io_executor(const Executor& ex,
325 typename enable_if<is_executor<Executor>::value>::type* = 0)
326 {
327 return ex;
328 }
329 } // namespace detail
330
331 #if !defined(GENERATING_DOCUMENTATION)
332 #if defined(ASIO_HAS_VARIADIC_TEMPLATES)
333
334 template <typename CompletionToken, typename Signature,
335 typename Implementation, typename... IoObjectsOrExecutors>
ASIO_INITFN_RESULT_TYPE(CompletionToken,Signature)336 ASIO_INITFN_RESULT_TYPE(CompletionToken, Signature)
337 async_compose(ASIO_MOVE_ARG(Implementation) implementation,
338 ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token,
339 ASIO_MOVE_ARG(IoObjectsOrExecutors)... io_objects_or_executors)
340 {
341 return async_initiate<CompletionToken, Signature>(
342 detail::initiate_composed_op<Signature>(), token,
343 ASIO_MOVE_CAST(Implementation)(implementation),
344 detail::make_composed_work(
345 detail::get_composed_io_executor(
346 ASIO_MOVE_CAST(IoObjectsOrExecutors)(
347 io_objects_or_executors))...));
348 }
349
350 #else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
351
352 template <typename CompletionToken, typename Signature, typename Implementation>
ASIO_INITFN_RESULT_TYPE(CompletionToken,Signature)353 ASIO_INITFN_RESULT_TYPE(CompletionToken, Signature)
354 async_compose(ASIO_MOVE_ARG(Implementation) implementation,
355 ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token)
356 {
357 return async_initiate<CompletionToken, Signature>(
358 detail::initiate_composed_op<Signature>(), token,
359 ASIO_MOVE_CAST(Implementation)(implementation),
360 detail::make_composed_work());
361 }
362
363 # define ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR(n) \
364 ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_##n
365
366 # define ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_1 \
367 detail::get_composed_io_executor(ASIO_MOVE_CAST(T1)(x1))
368 # define ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_2 \
369 detail::get_composed_io_executor(ASIO_MOVE_CAST(T1)(x1)), \
370 detail::get_composed_io_executor(ASIO_MOVE_CAST(T2)(x2))
371 # define ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_3 \
372 detail::get_composed_io_executor(ASIO_MOVE_CAST(T1)(x1)), \
373 detail::get_composed_io_executor(ASIO_MOVE_CAST(T2)(x2)), \
374 detail::get_composed_io_executor(ASIO_MOVE_CAST(T3)(x3))
375 # define ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_4 \
376 detail::get_composed_io_executor(ASIO_MOVE_CAST(T1)(x1)), \
377 detail::get_composed_io_executor(ASIO_MOVE_CAST(T2)(x2)), \
378 detail::get_composed_io_executor(ASIO_MOVE_CAST(T3)(x3)), \
379 detail::get_composed_io_executor(ASIO_MOVE_CAST(T4)(x4))
380 # define ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_5 \
381 detail::get_composed_io_executor(ASIO_MOVE_CAST(T1)(x1)), \
382 detail::get_composed_io_executor(ASIO_MOVE_CAST(T2)(x2)), \
383 detail::get_composed_io_executor(ASIO_MOVE_CAST(T3)(x3)), \
384 detail::get_composed_io_executor(ASIO_MOVE_CAST(T4)(x4)), \
385 detail::get_composed_io_executor(ASIO_MOVE_CAST(T5)(x5))
386
387 #define ASIO_PRIVATE_ASYNC_COMPOSE_DEF(n) \
388 template <typename CompletionToken, typename Signature, \
389 typename Implementation, ASIO_VARIADIC_TPARAMS(n)> \
390 ASIO_INITFN_RESULT_TYPE(CompletionToken, Signature) \
391 async_compose(ASIO_MOVE_ARG(Implementation) implementation, \
392 ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token, \
393 ASIO_VARIADIC_MOVE_PARAMS(n)) \
394 { \
395 return async_initiate<CompletionToken, Signature>( \
396 detail::initiate_composed_op<Signature>(), token, \
397 ASIO_MOVE_CAST(Implementation)(implementation), \
398 detail::make_composed_work( \
399 ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR(n))); \
400 } \
401 /**/
402 ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_ASYNC_COMPOSE_DEF)
403 #undef ASIO_PRIVATE_ASYNC_COMPOSE_DEF
404
405 #undef ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR
406 #undef ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_1
407 #undef ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_2
408 #undef ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_3
409 #undef ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_4
410 #undef ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_5
411
412 #endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
413 #endif // !defined(GENERATING_DOCUMENTATION)
414
415 } // namespace asio
416
417 #include "asio/detail/pop_options.hpp"
418
419 #endif // ASIO_IMPL_COMPOSE_HPP
420