Yi Kong | 7bf2a68 | 2019-04-18 17:30:49 -0700 | [diff] [blame] | 1 | // -*- C++ -*- |
| 2 | //===----------------------------- coroutine -----------------------------===// |
| 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_EXPERIMENTAL_COROUTINE |
| 11 | #define _LIBCPP_EXPERIMENTAL_COROUTINE |
| 12 | |
| 13 | /** |
| 14 | experimental/coroutine synopsis |
| 15 | |
| 16 | // C++next |
| 17 | |
| 18 | namespace std { |
| 19 | namespace experimental { |
| 20 | inline namespace coroutines_v1 { |
| 21 | |
| 22 | // 18.11.1 coroutine traits |
| 23 | template <typename R, typename... ArgTypes> |
| 24 | class coroutine_traits; |
| 25 | // 18.11.2 coroutine handle |
| 26 | template <typename Promise = void> |
| 27 | class coroutine_handle; |
| 28 | // 18.11.2.7 comparison operators: |
| 29 | bool operator==(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT; |
| 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 | // 18.11.3 trivial awaitables |
| 36 | struct suspend_never; |
| 37 | struct suspend_always; |
| 38 | // 18.11.2.8 hash support: |
| 39 | template <class T> struct hash; |
| 40 | template <class P> struct hash<coroutine_handle<P>>; |
| 41 | |
| 42 | } // namespace coroutines_v1 |
| 43 | } // namespace experimental |
| 44 | } // namespace std |
| 45 | |
| 46 | */ |
| 47 | |
| 48 | #include <experimental/__config> |
| 49 | #include <new> |
| 50 | #include <type_traits> |
| 51 | #include <functional> |
| 52 | #include <memory> // for hash<T*> |
| 53 | #include <cstddef> |
| 54 | #include <cassert> |
| 55 | #include <__debug> |
| 56 | |
| 57 | #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| 58 | #pragma GCC system_header |
| 59 | #endif |
| 60 | |
| 61 | #ifdef _LIBCPP_HAS_NO_COROUTINES |
| 62 | # if defined(_LIBCPP_WARNING) |
| 63 | _LIBCPP_WARNING("<experimental/coroutine> cannot be used with this compiler") |
| 64 | # else |
| 65 | # warning <experimental/coroutine> cannot be used with this compiler |
| 66 | # endif |
| 67 | #endif |
| 68 | |
| 69 | #ifndef _LIBCPP_HAS_NO_COROUTINES |
| 70 | |
| 71 | _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_COROUTINES |
| 72 | |
| 73 | template <class _Tp, class = void> |
| 74 | struct __coroutine_traits_sfinae {}; |
| 75 | |
| 76 | template <class _Tp> |
| 77 | struct __coroutine_traits_sfinae< |
| 78 | _Tp, typename __void_t<typename _Tp::promise_type>::type> |
| 79 | { |
| 80 | using promise_type = typename _Tp::promise_type; |
| 81 | }; |
| 82 | |
| 83 | template <typename _Ret, typename... _Args> |
| 84 | struct _LIBCPP_TEMPLATE_VIS coroutine_traits |
| 85 | : public __coroutine_traits_sfinae<_Ret> |
| 86 | { |
| 87 | }; |
| 88 | |
| 89 | template <typename _Promise = void> |
| 90 | class _LIBCPP_TEMPLATE_VIS coroutine_handle; |
| 91 | |
| 92 | template <> |
| 93 | class _LIBCPP_TEMPLATE_VIS coroutine_handle<void> { |
| 94 | public: |
| 95 | _LIBCPP_INLINE_VISIBILITY |
| 96 | _LIBCPP_CONSTEXPR coroutine_handle() _NOEXCEPT : __handle_(nullptr) {} |
| 97 | |
| 98 | _LIBCPP_INLINE_VISIBILITY |
| 99 | _LIBCPP_CONSTEXPR coroutine_handle(nullptr_t) _NOEXCEPT : __handle_(nullptr) {} |
| 100 | |
| 101 | _LIBCPP_INLINE_VISIBILITY |
| 102 | coroutine_handle& operator=(nullptr_t) _NOEXCEPT { |
| 103 | __handle_ = nullptr; |
| 104 | return *this; |
| 105 | } |
| 106 | |
| 107 | _LIBCPP_INLINE_VISIBILITY |
| 108 | _LIBCPP_CONSTEXPR void* address() const _NOEXCEPT { return __handle_; } |
| 109 | |
| 110 | _LIBCPP_INLINE_VISIBILITY |
| 111 | _LIBCPP_CONSTEXPR explicit operator bool() const _NOEXCEPT { return __handle_; } |
| 112 | |
| 113 | _LIBCPP_INLINE_VISIBILITY |
| 114 | void operator()() { resume(); } |
| 115 | |
| 116 | _LIBCPP_INLINE_VISIBILITY |
| 117 | void resume() { |
| 118 | _LIBCPP_ASSERT(__is_suspended(), |
| 119 | "resume() can only be called on suspended coroutines"); |
| 120 | _LIBCPP_ASSERT(!done(), |
| 121 | "resume() has undefined behavior when the coroutine is done"); |
| 122 | __builtin_coro_resume(__handle_); |
| 123 | } |
| 124 | |
| 125 | _LIBCPP_INLINE_VISIBILITY |
| 126 | void destroy() { |
| 127 | _LIBCPP_ASSERT(__is_suspended(), |
| 128 | "destroy() can only be called on suspended coroutines"); |
| 129 | __builtin_coro_destroy(__handle_); |
| 130 | } |
| 131 | |
| 132 | _LIBCPP_INLINE_VISIBILITY |
| 133 | bool done() const { |
| 134 | _LIBCPP_ASSERT(__is_suspended(), |
| 135 | "done() can only be called on suspended coroutines"); |
| 136 | return __builtin_coro_done(__handle_); |
| 137 | } |
| 138 | |
| 139 | public: |
| 140 | _LIBCPP_INLINE_VISIBILITY |
| 141 | static coroutine_handle from_address(void* __addr) _NOEXCEPT { |
| 142 | coroutine_handle __tmp; |
| 143 | __tmp.__handle_ = __addr; |
| 144 | return __tmp; |
| 145 | } |
| 146 | |
| 147 | // FIXME: Should from_address(nullptr) be allowed? |
| 148 | _LIBCPP_INLINE_VISIBILITY |
| 149 | static coroutine_handle from_address(nullptr_t) _NOEXCEPT { |
| 150 | return coroutine_handle(nullptr); |
| 151 | } |
| 152 | |
| 153 | template <class _Tp, bool _CallIsValid = false> |
| 154 | static coroutine_handle from_address(_Tp*) { |
| 155 | static_assert(_CallIsValid, |
| 156 | "coroutine_handle<void>::from_address cannot be called with " |
| 157 | "non-void pointers"); |
| 158 | } |
| 159 | |
| 160 | private: |
| 161 | bool __is_suspended() const _NOEXCEPT { |
| 162 | // FIXME actually implement a check for if the coro is suspended. |
| 163 | return __handle_; |
| 164 | } |
| 165 | |
| 166 | template <class _PromiseT> friend class coroutine_handle; |
| 167 | void* __handle_; |
| 168 | }; |
| 169 | |
| 170 | // 18.11.2.7 comparison operators: |
| 171 | inline _LIBCPP_INLINE_VISIBILITY |
| 172 | bool operator==(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT { |
| 173 | return __x.address() == __y.address(); |
| 174 | } |
| 175 | inline _LIBCPP_INLINE_VISIBILITY |
| 176 | bool operator!=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT { |
| 177 | return !(__x == __y); |
| 178 | } |
| 179 | inline _LIBCPP_INLINE_VISIBILITY |
| 180 | bool operator<(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT { |
| 181 | return less<void*>()(__x.address(), __y.address()); |
| 182 | } |
| 183 | inline _LIBCPP_INLINE_VISIBILITY |
| 184 | bool operator>(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT { |
| 185 | return __y < __x; |
| 186 | } |
| 187 | inline _LIBCPP_INLINE_VISIBILITY |
| 188 | bool operator<=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT { |
| 189 | return !(__x > __y); |
| 190 | } |
| 191 | inline _LIBCPP_INLINE_VISIBILITY |
| 192 | bool operator>=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT { |
| 193 | return !(__x < __y); |
| 194 | } |
| 195 | |
| 196 | template <typename _Promise> |
| 197 | class _LIBCPP_TEMPLATE_VIS coroutine_handle : public coroutine_handle<> { |
| 198 | using _Base = coroutine_handle<>; |
| 199 | public: |
| 200 | #ifndef _LIBCPP_CXX03_LANG |
| 201 | // 18.11.2.1 construct/reset |
| 202 | using coroutine_handle<>::coroutine_handle; |
| 203 | #else |
| 204 | _LIBCPP_INLINE_VISIBILITY coroutine_handle() _NOEXCEPT : _Base() {} |
| 205 | _LIBCPP_INLINE_VISIBILITY coroutine_handle(nullptr_t) _NOEXCEPT : _Base(nullptr) {} |
| 206 | #endif |
| 207 | _LIBCPP_INLINE_VISIBILITY |
| 208 | coroutine_handle& operator=(nullptr_t) _NOEXCEPT { |
| 209 | _Base::operator=(nullptr); |
| 210 | return *this; |
| 211 | } |
| 212 | |
| 213 | _LIBCPP_INLINE_VISIBILITY |
| 214 | _Promise& promise() const { |
| 215 | return *static_cast<_Promise*>( |
| 216 | __builtin_coro_promise(this->__handle_, _LIBCPP_ALIGNOF(_Promise), false)); |
| 217 | } |
| 218 | |
| 219 | public: |
| 220 | _LIBCPP_INLINE_VISIBILITY |
| 221 | static coroutine_handle from_address(void* __addr) _NOEXCEPT { |
| 222 | coroutine_handle __tmp; |
| 223 | __tmp.__handle_ = __addr; |
| 224 | return __tmp; |
| 225 | } |
| 226 | |
| 227 | // NOTE: this overload isn't required by the standard but is needed so |
| 228 | // the deleted _Promise* overload doesn't make from_address(nullptr) |
| 229 | // ambiguous. |
| 230 | // FIXME: should from_address work with nullptr? |
| 231 | _LIBCPP_INLINE_VISIBILITY |
| 232 | static coroutine_handle from_address(nullptr_t) _NOEXCEPT { |
| 233 | return coroutine_handle(nullptr); |
| 234 | } |
| 235 | |
| 236 | template <class _Tp, bool _CallIsValid = false> |
| 237 | static coroutine_handle from_address(_Tp*) { |
| 238 | static_assert(_CallIsValid, |
| 239 | "coroutine_handle<promise_type>::from_address cannot be called with " |
| 240 | "non-void pointers"); |
| 241 | } |
| 242 | |
| 243 | template <bool _CallIsValid = false> |
| 244 | static coroutine_handle from_address(_Promise*) { |
| 245 | static_assert(_CallIsValid, |
| 246 | "coroutine_handle<promise_type>::from_address cannot be used with " |
| 247 | "pointers to the coroutine's promise type; use 'from_promise' instead"); |
| 248 | } |
| 249 | |
| 250 | _LIBCPP_INLINE_VISIBILITY |
| 251 | static coroutine_handle from_promise(_Promise& __promise) _NOEXCEPT { |
| 252 | typedef typename remove_cv<_Promise>::type _RawPromise; |
| 253 | coroutine_handle __tmp; |
| 254 | __tmp.__handle_ = __builtin_coro_promise( |
| 255 | _VSTD::addressof(const_cast<_RawPromise&>(__promise)), |
| 256 | _LIBCPP_ALIGNOF(_Promise), true); |
| 257 | return __tmp; |
| 258 | } |
| 259 | }; |
| 260 | |
| 261 | #if __has_builtin(__builtin_coro_noop) |
| 262 | struct noop_coroutine_promise {}; |
| 263 | |
| 264 | template <> |
| 265 | class _LIBCPP_TEMPLATE_VIS coroutine_handle<noop_coroutine_promise> |
| 266 | : public coroutine_handle<> { |
| 267 | using _Base = coroutine_handle<>; |
| 268 | using _Promise = noop_coroutine_promise; |
| 269 | public: |
| 270 | |
| 271 | _LIBCPP_INLINE_VISIBILITY |
| 272 | _Promise& promise() const { |
| 273 | return *static_cast<_Promise*>( |
| 274 | __builtin_coro_promise(this->__handle_, _LIBCPP_ALIGNOF(_Promise), false)); |
| 275 | } |
| 276 | |
| 277 | _LIBCPP_CONSTEXPR explicit operator bool() const _NOEXCEPT { return true; } |
| 278 | _LIBCPP_CONSTEXPR bool done() const _NOEXCEPT { return false; } |
| 279 | |
| 280 | _LIBCPP_CONSTEXPR_AFTER_CXX17 void operator()() const _NOEXCEPT {} |
| 281 | _LIBCPP_CONSTEXPR_AFTER_CXX17 void resume() const _NOEXCEPT {} |
| 282 | _LIBCPP_CONSTEXPR_AFTER_CXX17 void destroy() const _NOEXCEPT {} |
| 283 | |
| 284 | private: |
| 285 | _LIBCPP_INLINE_VISIBILITY |
| 286 | friend coroutine_handle<noop_coroutine_promise> noop_coroutine() _NOEXCEPT; |
| 287 | |
| 288 | _LIBCPP_INLINE_VISIBILITY coroutine_handle() _NOEXCEPT { |
| 289 | this->__handle_ = __builtin_coro_noop(); |
| 290 | } |
| 291 | }; |
| 292 | |
| 293 | using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>; |
| 294 | |
| 295 | inline _LIBCPP_INLINE_VISIBILITY |
| 296 | noop_coroutine_handle noop_coroutine() _NOEXCEPT { |
| 297 | return noop_coroutine_handle(); |
| 298 | } |
| 299 | #endif // __has_builtin(__builtin_coro_noop) |
| 300 | |
| 301 | struct _LIBCPP_TYPE_VIS suspend_never { |
| 302 | _LIBCPP_INLINE_VISIBILITY |
| 303 | bool await_ready() const _NOEXCEPT { return true; } |
| 304 | _LIBCPP_INLINE_VISIBILITY |
| 305 | void await_suspend(coroutine_handle<>) const _NOEXCEPT {} |
| 306 | _LIBCPP_INLINE_VISIBILITY |
| 307 | void await_resume() const _NOEXCEPT {} |
| 308 | }; |
| 309 | |
| 310 | struct _LIBCPP_TYPE_VIS suspend_always { |
| 311 | _LIBCPP_INLINE_VISIBILITY |
| 312 | bool await_ready() const _NOEXCEPT { return false; } |
| 313 | _LIBCPP_INLINE_VISIBILITY |
| 314 | void await_suspend(coroutine_handle<>) const _NOEXCEPT {} |
| 315 | _LIBCPP_INLINE_VISIBILITY |
| 316 | void await_resume() const _NOEXCEPT {} |
| 317 | }; |
| 318 | |
| 319 | _LIBCPP_END_NAMESPACE_EXPERIMENTAL_COROUTINES |
| 320 | |
| 321 | _LIBCPP_BEGIN_NAMESPACE_STD |
| 322 | |
| 323 | template <class _Tp> |
| 324 | struct hash<_VSTD_CORO::coroutine_handle<_Tp> > { |
| 325 | using __arg_type = _VSTD_CORO::coroutine_handle<_Tp>; |
| 326 | _LIBCPP_INLINE_VISIBILITY |
| 327 | size_t operator()(__arg_type const& __v) const _NOEXCEPT |
| 328 | {return hash<void*>()(__v.address());} |
| 329 | }; |
| 330 | |
| 331 | _LIBCPP_END_NAMESPACE_STD |
| 332 | |
| 333 | #endif // !defined(_LIBCPP_HAS_NO_COROUTINES) |
| 334 | |
| 335 | #endif /* _LIBCPP_EXPERIMENTAL_COROUTINE */ |