1 // Copyright 2024 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 #pragma once 15 16 #include <type_traits> 17 18 #include "pw_async2/dispatcher.h" 19 20 namespace pw::async2 { 21 22 /// A ``Task`` that delegates to a type with a ``Pend`` method. 23 /// 24 /// The wrapped type must have a ``Pend`` method which accepts a ``Context&`` 25 /// and return a ``Poll<>``. 26 /// 27 /// If ``Pendable`` is a pointer, ``PendableAsTask`` will dereference it and 28 /// attempt to invoke ``Pend``. 29 template <typename Pendable> 30 class PendableAsTask : public Task { 31 public: 32 /// Create a new ``Task`` which delegates ``Pend`` to ``pendable``. 33 /// 34 /// See class docs for more details. PendableAsTask(Pendable && pendable)35 PendableAsTask(Pendable&& pendable) 36 : pendable_(std::forward<Pendable>(pendable)) {} 37 Pendable& operator*() { return pendable_; } 38 Pendable* operator->() { return &pendable_; } 39 40 private: DoPend(Context & cx)41 Poll<> DoPend(Context& cx) final { 42 if constexpr (std::is_pointer_v<Pendable>) { 43 return pendable_->Pend(cx); 44 } else { 45 return pendable_.Pend(cx); 46 } 47 } 48 Pendable pendable_; 49 }; 50 51 } // namespace pw::async2 52