1 // <experimental/io_service> -*- C++ -*- 2 3 // Copyright (C) 2015-2022 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file experimental/io_context 26 * This is a TS C++ Library header. 27 * @ingroup networking-ts 28 */ 29 30 #ifndef _GLIBCXX_EXPERIMENTAL_IO_SERVICE 31 #define _GLIBCXX_EXPERIMENTAL_IO_SERVICE 1 32 33 #pragma GCC system_header 34 35 #if __cplusplus >= 201402L 36 37 #include <atomic> 38 #include <forward_list> 39 #include <functional> 40 #include <system_error> 41 #include <thread> 42 #include <vector> 43 #include <experimental/netfwd> 44 #include <experimental/executor> 45 #include <bits/chrono.h> 46 #if _GLIBCXX_HAVE_UNISTD_H 47 # include <unistd.h> 48 #endif 49 #ifdef _GLIBCXX_HAVE_POLL_H 50 # include <poll.h> 51 #endif 52 #ifdef _GLIBCXX_HAVE_FCNTL_H 53 # include <fcntl.h> 54 #endif 55 56 namespace std _GLIBCXX_VISIBILITY(default) 57 { 58 _GLIBCXX_BEGIN_NAMESPACE_VERSION 59 namespace experimental 60 { 61 namespace net 62 { 63 inline namespace v1 64 { 65 66 /** @addtogroup networking-ts 67 * @{ 68 */ 69 70 class __socket_impl; 71 72 /// An ExecutionContext for I/O operations. 73 class io_context : public execution_context 74 { 75 public: 76 // types: 77 78 /// An executor for an io_context. 79 class executor_type 80 { 81 public: 82 // construct / copy / destroy: 83 84 executor_type(const executor_type& __other) noexcept = default; 85 executor_type(executor_type&& __other) noexcept = default; 86 87 executor_type& operator=(const executor_type& __other) noexcept = default; 88 executor_type& operator=(executor_type&& __other) noexcept = default; 89 90 // executor operations: 91 92 bool running_in_this_thread() const noexcept 93 { 94 #ifdef _GLIBCXX_HAS_GTHREADS 95 lock_guard<execution_context::mutex_type> __lock(_M_ctx->_M_mtx); 96 auto __end = _M_ctx->_M_call_stack.end(); 97 return std::find(_M_ctx->_M_call_stack.begin(), __end, 98 this_thread::get_id()) != __end; 99 #else 100 return _M_ctx->_M_run_count != 0; 101 #endif 102 } 103 104 io_context& context() const noexcept { return *_M_ctx; } 105 106 void on_work_started() const noexcept { ++_M_ctx->_M_work_count; } 107 void on_work_finished() const noexcept { --_M_ctx->_M_work_count; } 108 109 template<typename _Func, typename _ProtoAllocator> 110 void 111 dispatch(_Func&& __f, const _ProtoAllocator& __a) const 112 { 113 if (running_in_this_thread()) 114 decay_t<_Func>{std::forward<_Func>(__f)}(); 115 else 116 post(std::forward<_Func>(__f), __a); 117 } 118 119 template<typename _Func, typename _ProtoAllocator> 120 void 121 post(_Func&& __f, const _ProtoAllocator& __a) const 122 { 123 lock_guard<execution_context::mutex_type> __lock(_M_ctx->_M_mtx); 124 // TODO (re-use functionality in system_context) 125 _M_ctx->_M_reactor._M_notify(); 126 } 127 128 template<typename _Func, typename _ProtoAllocator> 129 void 130 defer(_Func&& __f, const _ProtoAllocator& __a) const 131 { post(std::forward<_Func>(__f), __a); } 132 133 private: 134 friend io_context; 135 136 explicit 137 executor_type(io_context& __ctx) : _M_ctx(std::addressof(__ctx)) { } 138 139 io_context* _M_ctx; 140 }; 141 142 using count_type = size_t; 143 144 // construct / copy / destroy: 145 146 io_context() : _M_work_count(0) { } 147 148 explicit 149 io_context(int __concurrency_hint) : _M_work_count(0) { } 150 151 io_context(const io_context&) = delete; 152 io_context& operator=(const io_context&) = delete; 153 154 // io_context operations: 155 156 executor_type get_executor() noexcept { return executor_type(*this); } 157 158 count_type 159 run() 160 { 161 count_type __n = 0; 162 while (run_one()) 163 if (__n != numeric_limits<count_type>::max()) 164 ++__n; 165 return __n; 166 } 167 168 template<typename _Rep, typename _Period> 169 count_type 170 run_for(const chrono::duration<_Rep, _Period>& __rel_time) 171 { return run_until(chrono::steady_clock::now() + __rel_time); } 172 173 template<typename _Clock, typename _Duration> 174 count_type 175 run_until(const chrono::time_point<_Clock, _Duration>& __abs_time) 176 { 177 count_type __n = 0; 178 while (run_one_until(__abs_time)) 179 if (__n != numeric_limits<count_type>::max()) 180 ++__n; 181 return __n; 182 } 183 184 count_type 185 run_one() 186 { return _M_do_one(chrono::milliseconds{-1}); } 187 188 template<typename _Rep, typename _Period> 189 count_type 190 run_one_for(const chrono::duration<_Rep, _Period>& __rel_time) 191 { return run_one_until(chrono::steady_clock::now() + __rel_time); } 192 193 template<typename _Clock, typename _Duration> 194 count_type 195 run_one_until(const chrono::time_point<_Clock, _Duration>& __abs_time) 196 { 197 auto __now = _Clock::now(); 198 while (__now < __abs_time) 199 { 200 using namespace std::chrono; 201 auto __ms = duration_cast<milliseconds>(__abs_time - __now); 202 if (_M_do_one(__ms)) 203 return 1; 204 __now = _Clock::now(); 205 } 206 return 0; 207 } 208 209 count_type 210 poll() 211 { 212 count_type __n = 0; 213 while (poll_one()) 214 if (__n != numeric_limits<count_type>::max()) 215 ++__n; 216 return __n; 217 } 218 219 count_type 220 poll_one() 221 { return _M_do_one(chrono::milliseconds{0}); } 222 223 void stop() 224 { 225 lock_guard<execution_context::mutex_type> __lock(_M_mtx); 226 _M_stopped = true; 227 _M_reactor._M_notify(); 228 } 229 230 bool stopped() const noexcept 231 { 232 lock_guard<execution_context::mutex_type> __lock(_M_mtx); 233 return _M_stopped; 234 } 235 236 void restart() 237 { 238 _M_stopped = false; 239 } 240 241 private: 242 243 template<typename _Clock, typename _WaitTraits> 244 friend class basic_waitable_timer; 245 246 friend __socket_impl; 247 248 template<typename _Protocol> 249 friend class __basic_socket_impl; 250 251 template<typename _Protocol> 252 friend class basic_socket; 253 254 template<typename _Protocol> 255 friend class basic_datagram_socket; 256 257 template<typename _Protocol> 258 friend class basic_stream_socket; 259 260 template<typename _Protocol> 261 friend class basic_socket_acceptor; 262 263 count_type 264 _M_outstanding_work() const 265 { return _M_work_count + !_M_ops.empty(); } 266 267 struct __timer_queue_base : execution_context::service 268 { 269 // return milliseconds until next timer expires, or milliseconds::max() 270 virtual chrono::milliseconds _M_next() const = 0; 271 virtual bool run_one() = 0; 272 273 protected: 274 explicit 275 __timer_queue_base(execution_context& __ctx) : service(__ctx) 276 { 277 auto& __ioc = static_cast<io_context&>(__ctx); 278 lock_guard<execution_context::mutex_type> __lock(__ioc._M_mtx); 279 __ioc._M_timers.push_back(this); 280 } 281 282 mutable execution_context::mutex_type _M_qmtx; 283 }; 284 285 template<typename _Timer, typename _Key = typename _Timer::_Key> 286 struct __timer_queue : __timer_queue_base 287 { 288 using key_type = __timer_queue; 289 290 explicit 291 __timer_queue(execution_context& __ctx) : __timer_queue_base(__ctx) 292 { } 293 294 void shutdown() noexcept { } 295 296 io_context& context() noexcept 297 { return static_cast<io_context&>(service::context()); } 298 299 // Start an asynchronous wait. 300 void 301 push(const _Timer& __t, function<void(error_code)> __h) 302 { 303 context().get_executor().on_work_started(); 304 lock_guard<execution_context::mutex_type> __lock(_M_qmtx); 305 _M_queue.emplace(__t, _M_next_id++, std::move(__h)); 306 // no need to notify reactor unless this timer went to the front? 307 } 308 309 // Cancel all outstanding waits for __t 310 size_t 311 cancel(const _Timer& __t) 312 { 313 lock_guard<execution_context::mutex_type> __lock(_M_qmtx); 314 size_t __count = 0; 315 auto __last = _M_queue.end(); 316 for (auto __it = _M_queue.begin(), __end = __last; __it != __end; 317 ++__it) 318 { 319 if (__it->_M_key == __t._M_key.get()) 320 { 321 __it->cancel(); 322 __last = __it; 323 ++__count; 324 } 325 } 326 if (__count) 327 _M_queue._M_sort_to(__last); 328 return __count; 329 } 330 331 // Cancel oldest outstanding wait for __t 332 bool 333 cancel_one(const _Timer& __t) 334 { 335 lock_guard<execution_context::mutex_type> __lock(_M_qmtx); 336 const auto __end = _M_queue.end(); 337 auto __oldest = __end; 338 for (auto __it = _M_queue.begin(); __it != __end; ++__it) 339 if (__it->_M_key == __t._M_key.get()) 340 if (__oldest == __end || __it->_M_id < __oldest->_M_id) 341 __oldest = __it; 342 if (__oldest == __end) 343 return false; 344 __oldest->cancel(); 345 _M_queue._M_sort_to(__oldest); 346 return true; 347 } 348 349 chrono::milliseconds 350 _M_next() const override 351 { 352 typename _Timer::time_point __exp; 353 { 354 lock_guard<execution_context::mutex_type> __lock(_M_qmtx); 355 if (_M_queue.empty()) 356 return chrono::milliseconds::max(); // no pending timers 357 if (_M_queue.top()._M_key == nullptr) 358 return chrono::milliseconds::zero(); // cancelled, run now 359 __exp = _M_queue.top()._M_expiry; 360 } 361 auto __dur = _Timer::traits_type::to_wait_duration(__exp); 362 if (__dur < __dur.zero()) 363 __dur = __dur.zero(); 364 return chrono::duration_cast<chrono::milliseconds>(__dur); 365 } 366 367 private: 368 369 bool run_one() override 370 { 371 auto __now = _Timer::clock_type::now(); 372 function<void(error_code)> __h; 373 error_code __ec; 374 { 375 lock_guard<execution_context::mutex_type> __lock(_M_qmtx); 376 377 if (_M_queue.top()._M_key == nullptr) // cancelled 378 { 379 __h = std::move(_M_queue.top()._M_h); 380 __ec = std::make_error_code(errc::operation_canceled); 381 _M_queue.pop(); 382 } 383 else if (_M_queue.top()._M_expiry <= _Timer::clock_type::now()) 384 { 385 __h = std::move(_M_queue.top()._M_h); 386 _M_queue.pop(); 387 } 388 } 389 if (__h) 390 { 391 __h(__ec); 392 context().get_executor().on_work_finished(); 393 return true; 394 } 395 return false; 396 } 397 398 using __timer_id_type = uint64_t; 399 400 struct __pending_timer 401 { 402 __pending_timer(const _Timer& __t, uint64_t __id, 403 function<void(error_code)> __h) 404 : _M_expiry(__t.expiry()), _M_key(__t._M_key.get()), _M_id(__id), 405 _M_h(std::move(__h)) 406 { } 407 408 typename _Timer::time_point _M_expiry; 409 _Key* _M_key; 410 __timer_id_type _M_id; 411 function<void(error_code)> _M_h; 412 413 void cancel() { _M_expiry = _M_expiry.min(); _M_key = nullptr; } 414 415 bool 416 operator<(const __pending_timer& __rhs) const 417 { return _M_expiry < __rhs._M_expiry; } 418 }; 419 420 struct __queue : priority_queue<__pending_timer> 421 { 422 using iterator = 423 typename priority_queue<__pending_timer>::container_type::iterator; 424 425 // expose begin/end/erase for direct access to underlying container 426 iterator begin() { return this->c.begin(); } 427 iterator end() { return this->c.end(); } 428 iterator erase(iterator __it) { return this->c.erase(__it); } 429 430 void 431 _M_sort_to(iterator __it) 432 { std::stable_sort(this->c.begin(), ++__it); } 433 }; 434 435 __queue _M_queue; 436 __timer_id_type _M_next_id = 0; 437 }; 438 439 template<typename _Timer, typename _CompletionHandler> 440 void 441 async_wait(const _Timer& __timer, _CompletionHandler&& __h) 442 { 443 auto& __queue = use_service<__timer_queue<_Timer>>(*this); 444 __queue.push(__timer, std::move(__h)); 445 _M_reactor._M_notify(); 446 } 447 448 // Cancel all wait operations initiated by __timer. 449 template<typename _Timer> 450 size_t 451 cancel(const _Timer& __timer) 452 { 453 if (!has_service<__timer_queue<_Timer>>(*this)) 454 return 0; 455 456 auto __c = use_service<__timer_queue<_Timer>>(*this).cancel(__timer); 457 if (__c != 0) 458 _M_reactor._M_notify(); 459 return __c; 460 } 461 462 // Cancel the oldest wait operation initiated by __timer. 463 template<typename _Timer> 464 size_t 465 cancel_one(const _Timer& __timer) 466 { 467 if (!has_service<__timer_queue<_Timer>>(*this)) 468 return 0; 469 470 if (use_service<__timer_queue<_Timer>>(*this).cancel_one(__timer)) 471 { 472 _M_reactor._M_notify(); 473 return 1; 474 } 475 return 0; 476 } 477 478 // The caller must know what the wait-type __w will be interpreted. 479 // In the current implementation the reactor is based on <poll.h> 480 // so the parameter must be one of POLLIN, POLLOUT or POLLERR. 481 template<typename _Op> 482 void 483 async_wait(int __fd, int __w, _Op&& __op) 484 { 485 lock_guard<execution_context::mutex_type> __lock(_M_mtx); 486 // TODO need push_back, use std::list not std::forward_list 487 auto __tail = _M_ops.before_begin(), __it = _M_ops.begin(); 488 while (__it != _M_ops.end()) 489 { 490 ++__it; 491 ++__tail; 492 } 493 using __type = __async_operation_impl<_Op>; 494 _M_ops.emplace_after(__tail, 495 make_unique<__type>(std::move(__op), __fd, __w)); 496 _M_reactor._M_fd_interest(__fd, __w); 497 } 498 499 void _M_add_fd(int __fd) { _M_reactor._M_add_fd(__fd); } 500 void _M_remove_fd(int __fd) { _M_reactor._M_remove_fd(__fd); } 501 502 void cancel(int __fd, error_code&) 503 { 504 lock_guard<execution_context::mutex_type> __lock(_M_mtx); 505 const auto __end = _M_ops.end(); 506 auto __it = _M_ops.begin(); 507 auto __prev = _M_ops.before_begin(); 508 while (__it != __end && (*__it)->_M_is_cancelled()) 509 { 510 ++__it; 511 ++__prev; 512 } 513 auto __cancelled = __prev; 514 while (__it != __end) 515 { 516 if ((*__it)->_M_fd == __fd) 517 { 518 (*__it)->cancel(); 519 ++__it; 520 _M_ops.splice_after(__cancelled, _M_ops, __prev); 521 ++__cancelled; 522 } 523 else 524 { 525 ++__it; 526 ++__prev; 527 } 528 } 529 _M_reactor._M_not_interested(__fd); 530 } 531 532 struct __async_operation 533 { 534 __async_operation(int __fd, int __ev) : _M_fd(__fd), _M_ev(__ev) { } 535 536 virtual ~__async_operation() = default; 537 538 int _M_fd; 539 short _M_ev; 540 541 void cancel() { _M_fd = -1; } 542 bool _M_is_cancelled() const { return _M_fd == -1; } 543 virtual void run(io_context&) = 0; 544 }; 545 546 template<typename _Op> 547 struct __async_operation_impl : __async_operation 548 { 549 __async_operation_impl(_Op&& __op, int __fd, int __ev) 550 : __async_operation{__fd, __ev}, _M_op(std::move(__op)) { } 551 552 _Op _M_op; 553 554 void run(io_context& __ctx) 555 { 556 if (_M_is_cancelled()) 557 _M_op(std::make_error_code(errc::operation_canceled)); 558 else 559 _M_op(error_code{}); 560 } 561 }; 562 563 atomic<count_type> _M_work_count; 564 mutable execution_context::mutex_type _M_mtx; 565 queue<function<void()>> _M_op; 566 bool _M_stopped = false; 567 568 struct __monitor 569 { 570 __monitor(io_context& __c) : _M_ctx(__c) 571 { 572 #ifdef _GLIBCXX_HAS_GTHREADS 573 lock_guard<execution_context::mutex_type> __lock(_M_ctx._M_mtx); 574 _M_ctx._M_call_stack.push_back(this_thread::get_id()); 575 #else 576 _M_ctx._M_run_count++; 577 #endif 578 } 579 580 ~__monitor() 581 { 582 #ifdef _GLIBCXX_HAS_GTHREADS 583 lock_guard<execution_context::mutex_type> __lock(_M_ctx._M_mtx); 584 _M_ctx._M_call_stack.pop_back(); 585 #else 586 _M_ctx._M_run_count--; 587 #endif 588 if (_M_ctx._M_outstanding_work() == 0) 589 { 590 _M_ctx._M_stopped = true; 591 _M_ctx._M_reactor._M_notify(); 592 } 593 } 594 595 __monitor(__monitor&&) = delete; 596 597 io_context& _M_ctx; 598 }; 599 600 bool 601 _M_do_one(chrono::milliseconds __timeout) 602 { 603 const bool __block = __timeout != chrono::milliseconds::zero(); 604 605 __reactor::__fdvec __fds; 606 607 __monitor __mon{*this}; 608 609 __timer_queue_base* __timerq = nullptr; 610 unique_ptr<__async_operation> __async_op; 611 612 while (true) 613 { 614 if (__timerq) 615 { 616 if (__timerq->run_one()) 617 return true; 618 else 619 __timerq = nullptr; 620 } 621 622 if (__async_op) 623 { 624 __async_op->run(*this); 625 // TODO need to unregister __async_op 626 return true; 627 } 628 629 chrono::milliseconds __ms{0}; 630 631 { 632 lock_guard<execution_context::mutex_type> __lock(_M_mtx); 633 634 if (_M_stopped) 635 return false; 636 637 // find first timer with something to do 638 for (auto __q : _M_timers) 639 { 640 auto __next = __q->_M_next(); 641 if (__next == __next.zero()) // ready to run immediately 642 { 643 __timerq = __q; 644 __ms = __next; 645 break; 646 } 647 else if (__next != __next.max() && __block 648 && (__next < __ms || __timerq == nullptr)) 649 { 650 __timerq = __q; 651 __ms = __next; 652 } 653 } 654 655 if (__timerq && __ms == __ms.zero()) 656 continue; // restart loop to run a timer immediately 657 658 if (!_M_ops.empty() && _M_ops.front()->_M_is_cancelled()) 659 { 660 _M_ops.front().swap(__async_op); 661 _M_ops.pop_front(); 662 continue; 663 } 664 665 // TODO run any posted items 666 667 if (__block) 668 { 669 if (__timerq == nullptr) 670 __ms = __timeout; 671 else if (__ms.zero() <= __timeout && __timeout < __ms) 672 __ms = __timeout; 673 else if (__ms.count() > numeric_limits<int>::max()) 674 __ms = chrono::milliseconds{numeric_limits<int>::max()}; 675 } 676 // else __ms == 0 and poll() will return immediately 677 678 } 679 680 auto __res = _M_reactor.wait(__fds, __ms); 681 682 if (__res == __reactor::_S_retry) 683 continue; 684 685 if (__res == __reactor::_S_timeout) 686 { 687 if (__timerq == nullptr) 688 return false; 689 else 690 continue; // timed out, so restart loop and process the timer 691 } 692 693 __timerq = nullptr; 694 695 if (__fds.empty()) // nothing to do 696 return false; 697 698 lock_guard<execution_context::mutex_type> __lock(_M_mtx); 699 for (auto __it = _M_ops.begin(), __end = _M_ops.end(), 700 __prev = _M_ops.before_begin(); __it != __end; ++__it, ++__prev) 701 { 702 auto& __op = **__it; 703 auto __pos = std::lower_bound(__fds.begin(), __fds.end(), 704 __op._M_fd, 705 [](const auto& __p, int __fd) { return __p.fd < __fd; }); 706 if (__pos != __fds.end() && __pos->fd == __op._M_fd 707 && __pos->revents & __op._M_ev) 708 { 709 __it->swap(__async_op); 710 _M_ops.erase_after(__prev); 711 break; // restart loop and run op 712 } 713 } 714 } 715 } 716 717 struct __reactor 718 { 719 #ifdef _GLIBCXX_HAVE_POLL_H 720 __reactor() : _M_fds(1) 721 { 722 int __pipe[2]; 723 if (::pipe(__pipe) == -1) 724 __throw_system_error(errno); 725 if (::fcntl(__pipe[0], F_SETFL, O_NONBLOCK) == -1 726 || ::fcntl(__pipe[1], F_SETFL, O_NONBLOCK) == -1) 727 { 728 int __e = errno; 729 ::close(__pipe[0]); 730 ::close(__pipe[1]); 731 __throw_system_error(__e); 732 } 733 _M_fds.back().events = POLLIN; 734 _M_fds.back().fd = __pipe[0]; 735 _M_notify_wr = __pipe[1]; 736 } 737 738 ~__reactor() 739 { 740 ::close(_M_fds.back().fd); 741 ::close(_M_notify_wr); 742 } 743 #endif 744 745 // write a notification byte to the pipe (ignoring errors) 746 void _M_notify() 747 { 748 int __n; 749 do { 750 __n = ::write(_M_notify_wr, "", 1); 751 } while (__n == -1 && errno == EINTR); 752 } 753 754 // read all notification bytes from the pipe 755 void _M_on_notify() 756 { 757 // Drain the pipe. 758 char __buf[64]; 759 ssize_t __n; 760 do { 761 __n = ::read(_M_fds.back().fd, __buf, sizeof(__buf)); 762 } while (__n != -1 || errno == EINTR); 763 } 764 765 void 766 _M_add_fd(int __fd) 767 { 768 auto __pos = _M_lower_bound(__fd); 769 if (__pos->fd == __fd) 770 __throw_system_error((int)errc::invalid_argument); 771 _M_fds.insert(__pos, __fdvec::value_type{})->fd = __fd; 772 _M_notify(); 773 } 774 775 void 776 _M_remove_fd(int __fd) 777 { 778 auto __pos = _M_lower_bound(__fd); 779 if (__pos->fd == __fd) 780 _M_fds.erase(__pos); 781 // else bug! 782 _M_notify(); 783 } 784 785 void 786 _M_fd_interest(int __fd, int __w) 787 { 788 auto __pos = _M_lower_bound(__fd); 789 if (__pos->fd == __fd) 790 __pos->events |= __w; 791 // else bug! 792 _M_notify(); 793 } 794 795 void 796 _M_not_interested(int __fd) 797 { 798 auto __pos = _M_lower_bound(__fd); 799 if (__pos->fd == __fd) 800 __pos->events = 0; 801 _M_notify(); 802 } 803 804 #ifdef _GLIBCXX_HAVE_POLL_H 805 using __fdvec = vector<::pollfd>; 806 #else 807 struct dummy_pollfd { int fd = -1; short events = 0, revents = 0; }; 808 using __fdvec = vector<dummy_pollfd>; 809 #endif 810 811 // Find first element p such that !(p.fd < __fd) 812 // N.B. always returns a dereferencable iterator. 813 __fdvec::iterator 814 _M_lower_bound(int __fd) 815 { 816 return std::lower_bound(_M_fds.begin(), _M_fds.end() - 1, 817 __fd, [](const auto& __p, int __fd) { return __p.fd < __fd; }); 818 } 819 820 enum __status { _S_retry, _S_timeout, _S_ok, _S_error }; 821 822 __status 823 wait(__fdvec& __fds, chrono::milliseconds __timeout) 824 { 825 #ifdef _GLIBCXX_HAVE_POLL_H 826 // XXX not thread-safe! 827 __fds = _M_fds; // take snapshot to pass to poll() 828 829 int __res = ::poll(__fds.data(), __fds.size(), __timeout.count()); 830 831 if (__res == -1) 832 { 833 __fds.clear(); 834 if (errno == EINTR) 835 return _S_retry; 836 return _S_error; // XXX ??? 837 } 838 else if (__res == 0) 839 { 840 __fds.clear(); 841 return _S_timeout; 842 } 843 else if (__fds.back().revents != 0) // something changed, restart 844 { 845 __fds.clear(); 846 _M_on_notify(); 847 return _S_retry; 848 } 849 850 auto __part = std::stable_partition(__fds.begin(), __fds.end() - 1, 851 [](const __fdvec::value_type& __p) { return __p.revents != 0; }); 852 __fds.erase(__part, __fds.end()); 853 854 return _S_ok; 855 #else 856 (void) __timeout; 857 __fds.clear(); 858 return _S_error; 859 #endif 860 } 861 862 __fdvec _M_fds; // _M_fds.back() is the read end of the self-pipe 863 int _M_notify_wr; // write end of the self-pipe 864 }; 865 866 __reactor _M_reactor; 867 868 vector<__timer_queue_base*> _M_timers; 869 forward_list<unique_ptr<__async_operation>> _M_ops; 870 871 #ifdef _GLIBCXX_HAS_GTHREADS 872 vector<thread::id> _M_call_stack; 873 #else 874 int _M_run_count = 0; 875 #endif 876 }; 877 878 inline bool 879 operator==(const io_context::executor_type& __a, 880 const io_context::executor_type& __b) noexcept 881 { 882 // https://github.com/chriskohlhoff/asio-tr2/issues/201 883 using executor_type = io_context::executor_type; 884 return std::addressof(executor_type(__a).context()) 885 == std::addressof(executor_type(__b).context()); 886 } 887 888 inline bool 889 operator!=(const io_context::executor_type& __a, 890 const io_context::executor_type& __b) noexcept 891 { return !(__a == __b); } 892 893 template<> struct is_executor<io_context::executor_type> : true_type {}; 894 895 /// @} 896 897 } // namespace v1 898 } // namespace net 899 } // namespace experimental 900 _GLIBCXX_END_NAMESPACE_VERSION 901 } // namespace std 902 903 #endif // C++14 904 905 #endif // _GLIBCXX_EXPERIMENTAL_IO_SERVICE 906
Indexes created Mon Mar 02 05:31:46 UTC 2026