1 | // |
2 | // detail/impl/task_io_service.ipp |
3 | // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
4 | // |
5 | // Copyright (c) 2003-2015 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_DETAIL_IMPL_TASK_IO_SERVICE_IPP |
12 | #define BOOST_ASIO_DETAIL_IMPL_TASK_IO_SERVICE_IPP |
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 | |
20 | #if !defined(BOOST_ASIO_HAS_IOCP) |
21 | |
22 | #include <boost/asio/detail/event.hpp> |
23 | #include <boost/asio/detail/limits.hpp> |
24 | #include <boost/asio/detail/reactor.hpp> |
25 | #include <boost/asio/detail/task_io_service.hpp> |
26 | #include <boost/asio/detail/task_io_service_thread_info.hpp> |
27 | |
28 | #include <boost/asio/detail/push_options.hpp> |
29 | |
30 | namespace boost { |
31 | namespace asio { |
32 | namespace detail { |
33 | |
34 | struct task_io_service::task_cleanup |
35 | { |
36 | ~task_cleanup() |
37 | { |
38 | if (this_thread_->private_outstanding_work > 0) |
39 | { |
40 | boost::asio::detail::increment( |
41 | a&: task_io_service_->outstanding_work_, |
42 | b: this_thread_->private_outstanding_work); |
43 | } |
44 | this_thread_->private_outstanding_work = 0; |
45 | |
46 | // Enqueue the completed operations and reinsert the task at the end of |
47 | // the operation queue. |
48 | lock_->lock(); |
49 | task_io_service_->task_interrupted_ = true; |
50 | task_io_service_->op_queue_.push(q&: this_thread_->private_op_queue); |
51 | task_io_service_->op_queue_.push(h: &task_io_service_->task_operation_); |
52 | } |
53 | |
54 | task_io_service* task_io_service_; |
55 | mutex::scoped_lock* lock_; |
56 | thread_info* this_thread_; |
57 | }; |
58 | |
59 | struct task_io_service::work_cleanup |
60 | { |
61 | ~work_cleanup() |
62 | { |
63 | if (this_thread_->private_outstanding_work > 1) |
64 | { |
65 | boost::asio::detail::increment( |
66 | a&: task_io_service_->outstanding_work_, |
67 | b: this_thread_->private_outstanding_work - 1); |
68 | } |
69 | else if (this_thread_->private_outstanding_work < 1) |
70 | { |
71 | task_io_service_->work_finished(); |
72 | } |
73 | this_thread_->private_outstanding_work = 0; |
74 | |
75 | #if defined(BOOST_ASIO_HAS_THREADS) |
76 | if (!this_thread_->private_op_queue.empty()) |
77 | { |
78 | lock_->lock(); |
79 | task_io_service_->op_queue_.push(q&: this_thread_->private_op_queue); |
80 | } |
81 | #endif // defined(BOOST_ASIO_HAS_THREADS) |
82 | } |
83 | |
84 | task_io_service* task_io_service_; |
85 | mutex::scoped_lock* lock_; |
86 | thread_info* this_thread_; |
87 | }; |
88 | |
89 | task_io_service::task_io_service( |
90 | boost::asio::io_service& io_service, std::size_t concurrency_hint) |
91 | : boost::asio::detail::service_base<task_io_service>(io_service), |
92 | one_thread_(concurrency_hint == 1), |
93 | mutex_(), |
94 | task_(0), |
95 | task_interrupted_(true), |
96 | outstanding_work_(0), |
97 | stopped_(false), |
98 | shutdown_(false) |
99 | { |
100 | BOOST_ASIO_HANDLER_TRACKING_INIT; |
101 | } |
102 | |
103 | void task_io_service::shutdown_service() |
104 | { |
105 | mutex::scoped_lock lock(mutex_); |
106 | shutdown_ = true; |
107 | lock.unlock(); |
108 | |
109 | // Destroy handler objects. |
110 | while (!op_queue_.empty()) |
111 | { |
112 | operation* o = op_queue_.front(); |
113 | op_queue_.pop(); |
114 | if (o != &task_operation_) |
115 | o->destroy(); |
116 | } |
117 | |
118 | // Reset to initial state. |
119 | task_ = 0; |
120 | } |
121 | |
122 | void task_io_service::init_task() |
123 | { |
124 | mutex::scoped_lock lock(mutex_); |
125 | if (!shutdown_ && !task_) |
126 | { |
127 | task_ = &use_service<reactor>(ios&: this->get_io_service()); |
128 | op_queue_.push(h: &task_operation_); |
129 | wake_one_thread_and_unlock(lock); |
130 | } |
131 | } |
132 | |
133 | std::size_t task_io_service::run(boost::system::error_code& ec) |
134 | { |
135 | ec = boost::system::error_code(); |
136 | if (outstanding_work_ == 0) |
137 | { |
138 | stop(); |
139 | return 0; |
140 | } |
141 | |
142 | thread_info this_thread; |
143 | this_thread.private_outstanding_work = 0; |
144 | thread_call_stack::context ctx(this, this_thread); |
145 | |
146 | mutex::scoped_lock lock(mutex_); |
147 | |
148 | std::size_t n = 0; |
149 | for (; do_run_one(lock, this_thread, ec); lock.lock()) |
150 | if (n != (std::numeric_limits<std::size_t>::max)()) |
151 | ++n; |
152 | return n; |
153 | } |
154 | |
155 | std::size_t task_io_service::run_one(boost::system::error_code& ec) |
156 | { |
157 | ec = boost::system::error_code(); |
158 | if (outstanding_work_ == 0) |
159 | { |
160 | stop(); |
161 | return 0; |
162 | } |
163 | |
164 | thread_info this_thread; |
165 | this_thread.private_outstanding_work = 0; |
166 | thread_call_stack::context ctx(this, this_thread); |
167 | |
168 | mutex::scoped_lock lock(mutex_); |
169 | |
170 | return do_run_one(lock, this_thread, ec); |
171 | } |
172 | |
173 | std::size_t task_io_service::poll(boost::system::error_code& ec) |
174 | { |
175 | ec = boost::system::error_code(); |
176 | if (outstanding_work_ == 0) |
177 | { |
178 | stop(); |
179 | return 0; |
180 | } |
181 | |
182 | thread_info this_thread; |
183 | this_thread.private_outstanding_work = 0; |
184 | thread_call_stack::context ctx(this, this_thread); |
185 | |
186 | mutex::scoped_lock lock(mutex_); |
187 | |
188 | #if defined(BOOST_ASIO_HAS_THREADS) |
189 | // We want to support nested calls to poll() and poll_one(), so any handlers |
190 | // that are already on a thread-private queue need to be put on to the main |
191 | // queue now. |
192 | if (one_thread_) |
193 | if (thread_info* outer_thread_info = ctx.next_by_key()) |
194 | op_queue_.push(q&: outer_thread_info->private_op_queue); |
195 | #endif // defined(BOOST_ASIO_HAS_THREADS) |
196 | |
197 | std::size_t n = 0; |
198 | for (; do_poll_one(lock, this_thread, ec); lock.lock()) |
199 | if (n != (std::numeric_limits<std::size_t>::max)()) |
200 | ++n; |
201 | return n; |
202 | } |
203 | |
204 | std::size_t task_io_service::poll_one(boost::system::error_code& ec) |
205 | { |
206 | ec = boost::system::error_code(); |
207 | if (outstanding_work_ == 0) |
208 | { |
209 | stop(); |
210 | return 0; |
211 | } |
212 | |
213 | thread_info this_thread; |
214 | this_thread.private_outstanding_work = 0; |
215 | thread_call_stack::context ctx(this, this_thread); |
216 | |
217 | mutex::scoped_lock lock(mutex_); |
218 | |
219 | #if defined(BOOST_ASIO_HAS_THREADS) |
220 | // We want to support nested calls to poll() and poll_one(), so any handlers |
221 | // that are already on a thread-private queue need to be put on to the main |
222 | // queue now. |
223 | if (one_thread_) |
224 | if (thread_info* outer_thread_info = ctx.next_by_key()) |
225 | op_queue_.push(q&: outer_thread_info->private_op_queue); |
226 | #endif // defined(BOOST_ASIO_HAS_THREADS) |
227 | |
228 | return do_poll_one(lock, this_thread, ec); |
229 | } |
230 | |
231 | void task_io_service::stop() |
232 | { |
233 | mutex::scoped_lock lock(mutex_); |
234 | stop_all_threads(lock); |
235 | } |
236 | |
237 | bool task_io_service::stopped() const |
238 | { |
239 | mutex::scoped_lock lock(mutex_); |
240 | return stopped_; |
241 | } |
242 | |
243 | void task_io_service::reset() |
244 | { |
245 | mutex::scoped_lock lock(mutex_); |
246 | stopped_ = false; |
247 | } |
248 | |
249 | void task_io_service::post_immediate_completion( |
250 | task_io_service::operation* op, bool is_continuation) |
251 | { |
252 | #if defined(BOOST_ASIO_HAS_THREADS) |
253 | if (one_thread_ || is_continuation) |
254 | { |
255 | if (thread_info* this_thread = thread_call_stack::contains(k: this)) |
256 | { |
257 | ++this_thread->private_outstanding_work; |
258 | this_thread->private_op_queue.push(h: op); |
259 | return; |
260 | } |
261 | } |
262 | #else // defined(BOOST_ASIO_HAS_THREADS) |
263 | (void)is_continuation; |
264 | #endif // defined(BOOST_ASIO_HAS_THREADS) |
265 | |
266 | work_started(); |
267 | mutex::scoped_lock lock(mutex_); |
268 | op_queue_.push(h: op); |
269 | wake_one_thread_and_unlock(lock); |
270 | } |
271 | |
272 | void task_io_service::post_deferred_completion(task_io_service::operation* op) |
273 | { |
274 | #if defined(BOOST_ASIO_HAS_THREADS) |
275 | if (one_thread_) |
276 | { |
277 | if (thread_info* this_thread = thread_call_stack::contains(k: this)) |
278 | { |
279 | this_thread->private_op_queue.push(h: op); |
280 | return; |
281 | } |
282 | } |
283 | #endif // defined(BOOST_ASIO_HAS_THREADS) |
284 | |
285 | mutex::scoped_lock lock(mutex_); |
286 | op_queue_.push(h: op); |
287 | wake_one_thread_and_unlock(lock); |
288 | } |
289 | |
290 | void task_io_service::post_deferred_completions( |
291 | op_queue<task_io_service::operation>& ops) |
292 | { |
293 | if (!ops.empty()) |
294 | { |
295 | #if defined(BOOST_ASIO_HAS_THREADS) |
296 | if (one_thread_) |
297 | { |
298 | if (thread_info* this_thread = thread_call_stack::contains(k: this)) |
299 | { |
300 | this_thread->private_op_queue.push(q&: ops); |
301 | return; |
302 | } |
303 | } |
304 | #endif // defined(BOOST_ASIO_HAS_THREADS) |
305 | |
306 | mutex::scoped_lock lock(mutex_); |
307 | op_queue_.push(q&: ops); |
308 | wake_one_thread_and_unlock(lock); |
309 | } |
310 | } |
311 | |
312 | void task_io_service::do_dispatch( |
313 | task_io_service::operation* op) |
314 | { |
315 | work_started(); |
316 | mutex::scoped_lock lock(mutex_); |
317 | op_queue_.push(h: op); |
318 | wake_one_thread_and_unlock(lock); |
319 | } |
320 | |
321 | void task_io_service::abandon_operations( |
322 | op_queue<task_io_service::operation>& ops) |
323 | { |
324 | op_queue<task_io_service::operation> ops2; |
325 | ops2.push(q&: ops); |
326 | } |
327 | |
328 | std::size_t task_io_service::do_run_one(mutex::scoped_lock& lock, |
329 | task_io_service::thread_info& this_thread, |
330 | const boost::system::error_code& ec) |
331 | { |
332 | while (!stopped_) |
333 | { |
334 | if (!op_queue_.empty()) |
335 | { |
336 | // Prepare to execute first handler from queue. |
337 | operation* o = op_queue_.front(); |
338 | op_queue_.pop(); |
339 | bool more_handlers = (!op_queue_.empty()); |
340 | |
341 | if (o == &task_operation_) |
342 | { |
343 | task_interrupted_ = more_handlers; |
344 | |
345 | if (more_handlers && !one_thread_) |
346 | wakeup_event_.unlock_and_signal_one(lock); |
347 | else |
348 | lock.unlock(); |
349 | |
350 | task_cleanup on_exit = { .task_io_service_: this, .lock_: &lock, .this_thread_: &this_thread }; |
351 | (void)on_exit; |
352 | |
353 | // Run the task. May throw an exception. Only block if the operation |
354 | // queue is empty and we're not polling, otherwise we want to return |
355 | // as soon as possible. |
356 | task_->run(block: !more_handlers, ops&: this_thread.private_op_queue); |
357 | } |
358 | else |
359 | { |
360 | std::size_t task_result = o->task_result_; |
361 | |
362 | if (more_handlers && !one_thread_) |
363 | wake_one_thread_and_unlock(lock); |
364 | else |
365 | lock.unlock(); |
366 | |
367 | // Ensure the count of outstanding work is decremented on block exit. |
368 | work_cleanup on_exit = { .task_io_service_: this, .lock_: &lock, .this_thread_: &this_thread }; |
369 | (void)on_exit; |
370 | |
371 | // Complete the operation. May throw an exception. Deletes the object. |
372 | o->complete(owner&: *this, ec, bytes_transferred: task_result); |
373 | |
374 | return 1; |
375 | } |
376 | } |
377 | else |
378 | { |
379 | wakeup_event_.clear(lock); |
380 | wakeup_event_.wait(lock); |
381 | } |
382 | } |
383 | |
384 | return 0; |
385 | } |
386 | |
387 | std::size_t task_io_service::do_poll_one(mutex::scoped_lock& lock, |
388 | task_io_service::thread_info& this_thread, |
389 | const boost::system::error_code& ec) |
390 | { |
391 | if (stopped_) |
392 | return 0; |
393 | |
394 | operation* o = op_queue_.front(); |
395 | if (o == &task_operation_) |
396 | { |
397 | op_queue_.pop(); |
398 | lock.unlock(); |
399 | |
400 | { |
401 | task_cleanup c = { .task_io_service_: this, .lock_: &lock, .this_thread_: &this_thread }; |
402 | (void)c; |
403 | |
404 | // Run the task. May throw an exception. Only block if the operation |
405 | // queue is empty and we're not polling, otherwise we want to return |
406 | // as soon as possible. |
407 | task_->run(block: false, ops&: this_thread.private_op_queue); |
408 | } |
409 | |
410 | o = op_queue_.front(); |
411 | if (o == &task_operation_) |
412 | { |
413 | wakeup_event_.maybe_unlock_and_signal_one(lock); |
414 | return 0; |
415 | } |
416 | } |
417 | |
418 | if (o == 0) |
419 | return 0; |
420 | |
421 | op_queue_.pop(); |
422 | bool more_handlers = (!op_queue_.empty()); |
423 | |
424 | std::size_t task_result = o->task_result_; |
425 | |
426 | if (more_handlers && !one_thread_) |
427 | wake_one_thread_and_unlock(lock); |
428 | else |
429 | lock.unlock(); |
430 | |
431 | // Ensure the count of outstanding work is decremented on block exit. |
432 | work_cleanup on_exit = { .task_io_service_: this, .lock_: &lock, .this_thread_: &this_thread }; |
433 | (void)on_exit; |
434 | |
435 | // Complete the operation. May throw an exception. Deletes the object. |
436 | o->complete(owner&: *this, ec, bytes_transferred: task_result); |
437 | |
438 | return 1; |
439 | } |
440 | |
441 | void task_io_service::stop_all_threads( |
442 | mutex::scoped_lock& lock) |
443 | { |
444 | stopped_ = true; |
445 | wakeup_event_.signal_all(lock); |
446 | |
447 | if (!task_interrupted_ && task_) |
448 | { |
449 | task_interrupted_ = true; |
450 | task_->interrupt(); |
451 | } |
452 | } |
453 | |
454 | void task_io_service::wake_one_thread_and_unlock( |
455 | mutex::scoped_lock& lock) |
456 | { |
457 | if (!wakeup_event_.maybe_unlock_and_signal_one(lock)) |
458 | { |
459 | if (!task_interrupted_ && task_) |
460 | { |
461 | task_interrupted_ = true; |
462 | task_->interrupt(); |
463 | } |
464 | lock.unlock(); |
465 | } |
466 | } |
467 | |
468 | } // namespace detail |
469 | } // namespace asio |
470 | } // namespace boost |
471 | |
472 | #include <boost/asio/detail/pop_options.hpp> |
473 | |
474 | #endif // !defined(BOOST_ASIO_HAS_IOCP) |
475 | |
476 | #endif // BOOST_ASIO_DETAIL_IMPL_TASK_IO_SERVICE_IPP |
477 | |