1 /* 2 * Copyright (c) 2021-2024 NVIDIA Corporation 3 * 4 * Licensed under the Apache License Version 2.0 with LLVM Exceptions 5 * (the "License"); you may not use this file except in compliance with 6 * the License. You may obtain a copy of the License at 7 * 8 * https://llvm.org/LICENSE.txt 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 #pragma once 17 18 #include "__execution_fwd.hpp" 19 20 // include these after __execution_fwd.hpp 21 #include "__awaitable.hpp" 22 #include "__completion_signatures.hpp" 23 #include "__concepts.hpp" 24 #include "__domain.hpp" 25 #include "__env.hpp" 26 #include "__receivers.hpp" 27 #include "__type_traits.hpp" 28 29 namespace stdexec 30 { 31 ///////////////////////////////////////////////////////////////////////////// 32 // [execution.senders] 33 struct sender_t 34 { 35 using sender_concept = sender_t; 36 }; 37 38 namespace __detail 39 { 40 template <class _Sender> 41 concept __enable_sender = // 42 derived_from<typename _Sender::sender_concept, sender_t> || 43 requires { typename _Sender::is_sender; } // NOT TO SPEC back compat 44 || __awaitable<_Sender, __env::__promise<empty_env>>; 45 } // namespace __detail 46 47 template <class _Sender> 48 inline constexpr bool enable_sender = __detail::__enable_sender<_Sender>; 49 50 template <class _Sender> 51 concept sender = // 52 enable_sender<__decay_t<_Sender>> // 53 && environment_provider<__cref_t<_Sender>> // 54 && __detail::__consistent_completion_domains<_Sender> // 55 && move_constructible<__decay_t<_Sender>> // 56 && constructible_from<__decay_t<_Sender>, _Sender>; 57 58 template <class _Sender, class... _Env> 59 concept sender_in = 60 (sizeof...(_Env) <= 1) // 61 && sender<_Sender> // 62 && requires(_Sender&& __sndr, _Env&&... __env) { 63 { 64 get_completion_signatures(static_cast<_Sender&&>(__sndr), 65 static_cast<_Env&&>(__env)...) 66 } -> __valid_completion_signatures; 67 }; 68 } // namespace stdexec 69