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 && _LIBCPP_HAS_THREADS
26
27struct nostopstate_t {
28 explicit nostopstate_t() = default;
29};
30
31inline constexpr nostopstate_t nostopstate{};
32
33class _LIBCPP_AVAILABILITY_SYNC stop_source {
34public:
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&: __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(other&: __rhs); }
82
83private:
84 __intrusive_shared_ptr<__stop_state> __state_;
85};
86
87#endif // _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_THREADS
88
89_LIBCPP_END_NAMESPACE_STD
90
91#endif // _LIBCPP___STOP_TOKEN_STOP_SOURCE_H
92