1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___STOP_TOKEN_STOP_SOURCE_H 11 #define _LIBCPP___STOP_TOKEN_STOP_SOURCE_H 12 13 #include <__config> 14 #include <__stop_token/intrusive_shared_ptr.h> 15 #include <__stop_token/stop_state.h> 16 #include <__stop_token/stop_token.h> 17 #include <__utility/move.h> 18 19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 20 # pragma GCC system_header 21 #endif 22 23 _LIBCPP_BEGIN_NAMESPACE_STD 24 25 #if _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN) && !defined(_LIBCPP_HAS_NO_THREADS) 26 27 struct nostopstate_t { 28 explicit nostopstate_t() = default; 29 }; 30 31 inline constexpr nostopstate_t nostopstate{}; 32 33 class _LIBCPP_AVAILABILITY_SYNC stop_source { 34 public: 35 _LIBCPP_HIDE_FROM_ABI stop_source() : __state_(new __stop_state()) { __state_->__increment_stop_source_counter(); } 36 37 _LIBCPP_HIDE_FROM_ABI explicit stop_source(nostopstate_t) noexcept : __state_(nullptr) {} 38 39 _LIBCPP_HIDE_FROM_ABI stop_source(const stop_source& __other) noexcept : __state_(__other.__state_) { 40 if (__state_) { 41 __state_->__increment_stop_source_counter(); 42 } 43 } 44 45 _LIBCPP_HIDE_FROM_ABI stop_source(stop_source&& __other) noexcept = default; 46 47 _LIBCPP_HIDE_FROM_ABI stop_source& operator=(const stop_source& __other) noexcept { 48 // increment `__other` first so that we don't hit 0 in case of self-assignment 49 if (__other.__state_) { 50 __other.__state_->__increment_stop_source_counter(); 51 } 52 if (__state_) { 53 __state_->__decrement_stop_source_counter(); 54 } 55 __state_ = __other.__state_; 56 return *this; 57 } 58 59 _LIBCPP_HIDE_FROM_ABI stop_source& operator=(stop_source&&) noexcept = default; 60 61 _LIBCPP_HIDE_FROM_ABI ~stop_source() { 62 if (__state_) { 63 __state_->__decrement_stop_source_counter(); 64 } 65 } 66 67 _LIBCPP_HIDE_FROM_ABI void swap(stop_source& __other) noexcept { __state_.swap(__other.__state_); } 68 69 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI stop_token get_token() const noexcept { return stop_token(__state_); } 70 71 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool stop_possible() const noexcept { return __state_ != nullptr; } 72 73 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool stop_requested() const noexcept { 74 return __state_ != nullptr && __state_->__stop_requested(); 75 } 76 77 _LIBCPP_HIDE_FROM_ABI bool request_stop() noexcept { return __state_ && __state_->__request_stop(); } 78 79 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI friend bool operator==(const stop_source&, const stop_source&) noexcept = default; 80 81 _LIBCPP_HIDE_FROM_ABI friend void swap(stop_source& __lhs, stop_source& __rhs) noexcept { __lhs.swap(__rhs); } 82 83 private: 84 __intrusive_shared_ptr<__stop_state> __state_; 85 }; 86 87 #endif // _LIBCPP_STD_VER >= 20 88 89 _LIBCPP_END_NAMESPACE_STD 90 91 #endif // _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN) && !defined(_LIBCPP_HAS_NO_THREADS) 92