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 <__availability> 14 #include <__config> 15 #include <__stop_token/intrusive_shared_ptr.h> 16 #include <__stop_token/stop_state.h> 17 #include <__stop_token/stop_token.h> 18 #include <__utility/move.h> 19 20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 21 # pragma GCC system_header 22 #endif 23 24 _LIBCPP_BEGIN_NAMESPACE_STD 25 26 #if _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN) 27 28 struct nostopstate_t { 29 explicit nostopstate_t() = default; 30 }; 31 32 inline constexpr nostopstate_t nostopstate{}; 33 34 class _LIBCPP_AVAILABILITY_SYNC stop_source { 35 public: 36 _LIBCPP_HIDE_FROM_ABI stop_source() : __state_(new __stop_state()) { __state_->__increment_stop_source_counter(); } 37 38 _LIBCPP_HIDE_FROM_ABI explicit stop_source(nostopstate_t) noexcept : __state_(nullptr) {} 39 40 _LIBCPP_HIDE_FROM_ABI stop_source(const stop_source& __other) noexcept : __state_(__other.__state_) { 41 if (__state_) { 42 __state_->__increment_stop_source_counter(); 43 } 44 } 45 46 _LIBCPP_HIDE_FROM_ABI stop_source(stop_source&& __other) noexcept = default; 47 48 _LIBCPP_HIDE_FROM_ABI stop_source& operator=(const stop_source& __other) noexcept { 49 // increment `__other` first so that we don't hit 0 in case of self-assignment 50 if (__other.__state_) { 51 __other.__state_->__increment_stop_source_counter(); 52 } 53 if (__state_) { 54 __state_->__decrement_stop_source_counter(); 55 } 56 __state_ = __other.__state_; 57 return *this; 58 } 59 60 _LIBCPP_HIDE_FROM_ABI stop_source& operator=(stop_source&&) noexcept = default; 61 62 _LIBCPP_HIDE_FROM_ABI ~stop_source() { 63 if (__state_) { 64 __state_->__decrement_stop_source_counter(); 65 } 66 } 67 68 _LIBCPP_HIDE_FROM_ABI void swap(stop_source& __other) noexcept { __state_.swap(__other.__state_); } 69 70 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI stop_token get_token() const noexcept { return stop_token(__state_); } 71 72 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool stop_possible() const noexcept { return __state_ != nullptr; } 73 74 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool stop_requested() const noexcept { 75 return __state_ != nullptr && __state_->__stop_requested(); 76 } 77 78 _LIBCPP_HIDE_FROM_ABI bool request_stop() noexcept { return __state_ && __state_->__request_stop(); } 79 80 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI friend bool operator==(const stop_source&, const stop_source&) noexcept = default; 81 82 _LIBCPP_HIDE_FROM_ABI friend void swap(stop_source& __lhs, stop_source& __rhs) noexcept { __lhs.swap(__rhs); } 83 84 private: 85 __intrusive_shared_ptr<__stop_state> __state_; 86 }; 87 88 #endif // _LIBCPP_STD_VER >= 20 89 90 _LIBCPP_END_NAMESPACE_STD 91 92 #endif // _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN) 93