87 lines
2.4 KiB
C++
87 lines
2.4 KiB
C++
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <folly/experimental/observer/Observable.h>
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namespace folly {
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namespace observer {
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template <typename T>
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template <typename, typename>
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SimpleObservable<T>::SimpleObservable()
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: context_(std::make_shared<Context>(std::make_shared<T>())) {}
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template <typename T>
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SimpleObservable<T>::SimpleObservable(T value)
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: SimpleObservable(std::make_shared<const T>(std::move(value))) {}
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template <typename T>
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SimpleObservable<T>::SimpleObservable(std::shared_ptr<const T> value)
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: context_(std::make_shared<Context>(std::move(value))) {}
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template <typename T>
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void SimpleObservable<T>::setValue(T value) {
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setValue(std::make_shared<const T>(std::move(value)));
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}
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template <typename T>
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void SimpleObservable<T>::setValue(std::shared_ptr<const T> value) {
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context_->value_.swap(value);
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context_->callback_.withWLock([](folly::Function<void()>& callback) {
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if (callback) {
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callback();
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}
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});
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}
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template <typename T>
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SimpleObservable<T>::Context::Context(std::shared_ptr<const T> value)
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: value_{std::move(value)} {}
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template <typename T>
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struct SimpleObservable<T>::Wrapper {
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using element_type = T;
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std::shared_ptr<Context> context;
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std::shared_ptr<const T> get() { return context->value_.copy(); }
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void subscribe(folly::Function<void()> callback) {
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context->callback_.swap(callback);
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}
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void unsubscribe() {
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Function<void()> empty;
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context->callback_.swap(empty);
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}
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};
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template <typename T>
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auto SimpleObservable<T>::getObserver() const {
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return observer_.try_emplace_with([&]() {
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SimpleObservable<T>::Wrapper wrapper;
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wrapper.context = context_;
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ObserverCreator<SimpleObservable<T>::Wrapper> creator(std::move(wrapper));
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return unwrap(std::move(creator).getObserver());
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});
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}
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} // namespace observer
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} // namespace folly
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