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_CALLBACK_H
11#define _LIBCPP___STOP_TOKEN_STOP_CALLBACK_H
12
13#include <__concepts/constructible.h>
14#include <__concepts/destructible.h>
15#include <__concepts/invocable.h>
16#include <__config>
17#include <__stop_token/intrusive_shared_ptr.h>
18#include <__stop_token/stop_state.h>
19#include <__stop_token/stop_token.h>
20#include <__type_traits/is_nothrow_constructible.h>
21#include <__utility/forward.h>
22#include <__utility/move.h>
23#include <__utility/private_constructor_tag.h>
24
25#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26# pragma GCC system_header
27#endif
28
29_LIBCPP_PUSH_MACROS
30#include <__undef_macros>
31
32_LIBCPP_BEGIN_NAMESPACE_STD
33
34#if _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_THREADS
35
36template <class _Callback>
37class _LIBCPP_AVAILABILITY_SYNC stop_callback : private __stop_callback_base {
38 static_assert(invocable<_Callback>,
39 "Mandates: stop_callback is instantiated with an argument for the template parameter Callback that "
40 "satisfies invocable.");
41 static_assert(destructible<_Callback>,
42 "Mandates: stop_callback is instantiated with an argument for the template parameter Callback that "
43 "satisfies destructible.");
44
45public:
46 using callback_type = _Callback;
47
48 template <class _Cb>
49 requires constructible_from<_Callback, _Cb>
50 _LIBCPP_HIDE_FROM_ABI explicit stop_callback(const stop_token& __st,
51 _Cb&& __cb) noexcept(is_nothrow_constructible_v<_Callback, _Cb>)
52 : stop_callback(__private_constructor_tag{}, __st.__state_, std::forward<_Cb>(__cb)) {}
53
54 template <class _Cb>
55 requires constructible_from<_Callback, _Cb>
56 _LIBCPP_HIDE_FROM_ABI explicit stop_callback(stop_token&& __st,
57 _Cb&& __cb) noexcept(is_nothrow_constructible_v<_Callback, _Cb>)
58 : stop_callback(__private_constructor_tag{}, std::move(__st.__state_), std::forward<_Cb>(__cb)) {}
59
60 _LIBCPP_HIDE_FROM_ABI ~stop_callback() {
61 if (__state_) {
62 __state_->__remove_callback(cb: this);
63 }
64 }
65
66 stop_callback(const stop_callback&) = delete;
67 stop_callback(stop_callback&&) = delete;
68 stop_callback& operator=(const stop_callback&) = delete;
69 stop_callback& operator=(stop_callback&&) = delete;
70
71private:
72 _LIBCPP_NO_UNIQUE_ADDRESS _Callback __callback_;
73 __intrusive_shared_ptr<__stop_state> __state_;
74
75 friend __stop_callback_base;
76
77 template <class _StatePtr, class _Cb>
78 _LIBCPP_HIDE_FROM_ABI explicit stop_callback(__private_constructor_tag, _StatePtr&& __state, _Cb&& __cb) noexcept(
79 is_nothrow_constructible_v<_Callback, _Cb>)
80 : __stop_callback_base([](__stop_callback_base* __cb_base) noexcept {
81 // stop callback is supposed to only be called once
82 std::forward<_Callback>(static_cast<stop_callback*>(__cb_base)->__callback_)();
83 }),
84 __callback_(std::forward<_Cb>(__cb)),
85 __state_() {
86 if (__state && __state->__add_callback(this)) {
87 // st.stop_requested() was false and this is successfully added to the linked list
88 __state_ = std::forward<_StatePtr>(__state);
89 }
90 }
91};
92
93template <class _Callback>
94_LIBCPP_AVAILABILITY_SYNC stop_callback(stop_token, _Callback) -> stop_callback<_Callback>;
95
96#endif // _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_THREADS
97
98_LIBCPP_END_NAMESPACE_STD
99
100_LIBCPP_POP_MACROS
101
102#endif // _LIBCPP___STOP_TOKEN_STOP_CALLBACK_H
103