1 /* 2 * Copyright (c) Facebook, Inc. and its affiliates. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 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 17 #pragma once 18 19 #include <folly/experimental/observer/Observer.h> 20 #include <folly/synchronization/Baton.h> 21 22 namespace folly { 23 namespace observer { 24 25 namespace detail { 26 template <typename Observable, typename Traits> 27 class ObserverCreatorContext; 28 } 29 30 template <typename Observable> 31 struct ObservableTraits { 32 using element_type = 33 typename std::remove_reference<Observable>::type::element_type; 34 getObservableTraits35 static std::shared_ptr<const element_type> get(Observable& observable) { 36 return observable.get(); 37 } 38 39 template <typename F> subscribeObservableTraits40 static void subscribe(Observable& observable, F&& callback) { 41 observable.subscribe(std::forward<F>(callback)); 42 } 43 unsubscribeObservableTraits44 static void unsubscribe(Observable& observable) { observable.unsubscribe(); } 45 }; 46 47 template <typename Observable, typename Traits = ObservableTraits<Observable>> 48 class ObserverCreator { 49 public: 50 using T = typename Traits::element_type; 51 52 template <typename... Args> 53 explicit ObserverCreator(Args&&... args); 54 55 Observer<T> getObserver() &&; 56 57 private: 58 using Context = detail::ObserverCreatorContext<Observable, Traits>; 59 class ContextPrimaryPtr; 60 61 std::shared_ptr<Context> context_; 62 }; 63 } // namespace observer 64 } // namespace folly 65 66 #include <folly/experimental/observer/Observable-inl.h> 67