2 //===----------------------------- coroutine -----------------------------===//
4 // The LLVM Compiler Infrastructure
6 // This file is distributed under the University of Illinois Open Source
7 // License. See LICENSE.TXT for details.
9 //===----------------------------------------------------------------------===//
11 #ifndef _LIBCPP_EXPERIMENTAL_COROUTINE
12 #define _LIBCPP_EXPERIMENTAL_COROUTINE
15 experimental/coroutine synopsis
20 namespace experimental {
21 inline namespace coroutines_v1 {
23 // 18.11.1 coroutine traits
24 template <typename R, typename... ArgTypes>
25 class coroutine_traits;
26 // 18.11.2 coroutine handle
27 template <typename Promise = void>
28 class coroutine_handle;
29 // 18.11.2.7 comparison operators:
30 bool operator==(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
31 bool operator!=(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
32 bool operator<(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
33 bool operator<=(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
34 bool operator>=(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
35 bool operator>(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
36 // 18.11.3 trivial awaitables
38 struct suspend_always;
39 // 18.11.2.8 hash support:
40 template <class T> struct hash;
41 template <class P> struct hash<coroutine_handle<P>>;
43 } // namespace coroutines_v1
44 } // namespace experimental
49 #include <experimental/__config>
51 #include <type_traits>
53 #include <memory> // for hash<T*>
58 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
59 #pragma GCC system_header
62 #ifdef _LIBCPP_HAS_NO_COROUTINES
63 # if defined(_LIBCPP_WARNING)
64 _LIBCPP_WARNING("<experimental/coroutine> cannot be used with this compiler")
66 # warning <experimental/coroutine> cannot be used with this compiler
70 #ifndef _LIBCPP_HAS_NO_COROUTINES
72 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_COROUTINES
74 template <class _Tp, class = void>
75 struct __coroutine_traits_sfinae {};
78 struct __coroutine_traits_sfinae<
79 _Tp, typename __void_t<typename _Tp::promise_type>::type>
81 using promise_type = typename _Tp::promise_type;
84 template <typename _Ret, typename... _Args>
85 struct _LIBCPP_TEMPLATE_VIS coroutine_traits
86 : public __coroutine_traits_sfinae<_Ret>
90 template <typename _Promise = void>
91 class _LIBCPP_TEMPLATE_VIS coroutine_handle;
94 class _LIBCPP_TEMPLATE_VIS coroutine_handle<void> {
97 _LIBCPP_CONSTEXPR coroutine_handle() _NOEXCEPT : __handle_(nullptr) {}
100 _LIBCPP_CONSTEXPR coroutine_handle(nullptr_t) _NOEXCEPT : __handle_(nullptr) {}
102 _LIBCPP_ALWAYS_INLINE
103 coroutine_handle& operator=(nullptr_t) _NOEXCEPT {
108 _LIBCPP_ALWAYS_INLINE
109 _LIBCPP_CONSTEXPR void* address() const _NOEXCEPT { return __handle_; }
111 _LIBCPP_ALWAYS_INLINE
112 _LIBCPP_CONSTEXPR explicit operator bool() const _NOEXCEPT { return __handle_; }
114 _LIBCPP_ALWAYS_INLINE
115 void operator()() { resume(); }
117 _LIBCPP_ALWAYS_INLINE
119 _LIBCPP_ASSERT(__is_suspended(),
120 "resume() can only be called on suspended coroutines");
121 _LIBCPP_ASSERT(!done(),
122 "resume() has undefined behavior when the coroutine is done");
123 __builtin_coro_resume(__handle_);
126 _LIBCPP_ALWAYS_INLINE
128 _LIBCPP_ASSERT(__is_suspended(),
129 "destroy() can only be called on suspended coroutines");
130 __builtin_coro_destroy(__handle_);
133 _LIBCPP_ALWAYS_INLINE
135 _LIBCPP_ASSERT(__is_suspended(),
136 "done() can only be called on suspended coroutines");
137 return __builtin_coro_done(__handle_);
141 _LIBCPP_ALWAYS_INLINE
142 static coroutine_handle from_address(void* __addr) _NOEXCEPT {
143 coroutine_handle __tmp;
144 __tmp.__handle_ = __addr;
149 bool __is_suspended() const _NOEXCEPT {
150 // FIXME actually implement a check for if the coro is suspended.
154 template <class _PromiseT> friend class coroutine_handle;
158 // 18.11.2.7 comparison operators:
159 inline _LIBCPP_ALWAYS_INLINE
160 bool operator==(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
161 return __x.address() == __y.address();
163 inline _LIBCPP_ALWAYS_INLINE
164 bool operator!=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
165 return !(__x == __y);
167 inline _LIBCPP_ALWAYS_INLINE
168 bool operator<(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
169 return less<void*>()(__x.address(), __y.address());
171 inline _LIBCPP_ALWAYS_INLINE
172 bool operator>(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
175 inline _LIBCPP_ALWAYS_INLINE
176 bool operator<=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
179 inline _LIBCPP_ALWAYS_INLINE
180 bool operator>=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
184 template <typename _Promise>
185 class _LIBCPP_TEMPLATE_VIS coroutine_handle : public coroutine_handle<> {
186 using _Base = coroutine_handle<>;
188 #ifndef _LIBCPP_CXX03_LANG
189 // 18.11.2.1 construct/reset
190 using coroutine_handle<>::coroutine_handle;
192 _LIBCPP_ALWAYS_INLINE coroutine_handle() _NOEXCEPT : _Base() {}
193 _LIBCPP_ALWAYS_INLINE coroutine_handle(nullptr_t) _NOEXCEPT : _Base(nullptr) {}
195 _LIBCPP_INLINE_VISIBILITY
196 coroutine_handle& operator=(nullptr_t) _NOEXCEPT {
197 _Base::operator=(nullptr);
201 _LIBCPP_INLINE_VISIBILITY
202 _Promise& promise() const {
203 return *reinterpret_cast<_Promise*>(
204 __builtin_coro_promise(this->__handle_, __alignof(_Promise), false));
208 _LIBCPP_ALWAYS_INLINE
209 static coroutine_handle from_address(void* __addr) _NOEXCEPT {
210 coroutine_handle __tmp;
211 __tmp.__handle_ = __addr;
215 // NOTE: this overload isn't required by the standard but is needed so
216 // the deleted _Promise* overload doesn't make from_address(nullptr)
218 // FIXME: should from_address work with nullptr?
219 _LIBCPP_ALWAYS_INLINE
220 static coroutine_handle from_address(nullptr_t) _NOEXCEPT {
224 // from_address cannot be used with the coroutines promise type.
225 static coroutine_handle from_address(_Promise*) = delete;
227 _LIBCPP_ALWAYS_INLINE
228 static coroutine_handle from_promise(_Promise& __promise) _NOEXCEPT {
229 coroutine_handle __tmp;
230 __tmp.__handle_ = __builtin_coro_promise(_VSTD::addressof(__promise),
231 __alignof(_Promise), true);
236 struct _LIBCPP_TYPE_VIS suspend_never {
237 _LIBCPP_ALWAYS_INLINE
238 bool await_ready() const _NOEXCEPT { return true; }
239 _LIBCPP_ALWAYS_INLINE
240 void await_suspend(coroutine_handle<>) const _NOEXCEPT {}
241 _LIBCPP_ALWAYS_INLINE
242 void await_resume() const _NOEXCEPT {}
245 struct _LIBCPP_TYPE_VIS suspend_always {
246 _LIBCPP_ALWAYS_INLINE
247 bool await_ready() const _NOEXCEPT { return false; }
248 _LIBCPP_ALWAYS_INLINE
249 void await_suspend(coroutine_handle<>) const _NOEXCEPT {}
250 _LIBCPP_ALWAYS_INLINE
251 void await_resume() const _NOEXCEPT {}
254 _LIBCPP_END_NAMESPACE_EXPERIMENTAL_COROUTINES
256 _LIBCPP_BEGIN_NAMESPACE_STD
259 struct hash<_VSTD_CORO::coroutine_handle<_Tp> > {
260 using __arg_type = _VSTD_CORO::coroutine_handle<_Tp>;
261 _LIBCPP_INLINE_VISIBILITY
262 size_t operator()(__arg_type const& __v) const _NOEXCEPT
263 {return hash<void*>()(__v.address());}
266 _LIBCPP_END_NAMESPACE_STD
268 #endif // !defined(_LIBCPP_HAS_NO_COROUTINES)
270 #endif /* _LIBCPP_EXPERIMENTAL_COROUTINE */