88 lines
2.0 KiB
C++
88 lines
2.0 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/functional/Invoke.h>
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namespace folly {
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namespace observer {
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template <typename T>
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class Observer;
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}
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namespace observer_detail {
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template <typename T>
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struct NonSharedPtr {
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using type = typename std::decay<T>::type;
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};
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template <typename T>
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struct NonSharedPtr<std::shared_ptr<T>> {};
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template <typename T>
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struct NonObserver {
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using type = typename std::decay<T>::type;
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};
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template <typename T>
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struct NonObserver<observer::Observer<T>> {};
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template <typename T>
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struct UnwrapSharedPtr {};
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template <typename T>
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struct UnwrapSharedPtr<std::shared_ptr<T>> {
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using type = typename std::decay<T>::type;
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};
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template <typename T>
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struct UnwrapObserver {};
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template <typename T>
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struct UnwrapObserver<observer::Observer<T>> {
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using type = T;
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};
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template <typename F>
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using ResultOf =
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typename NonObserver<typename NonSharedPtr<invoke_result_t<F>>::type>::type;
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template <typename F>
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using ResultOfNoObserverUnwrap =
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typename NonSharedPtr<invoke_result_t<F>>::type;
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template <typename F>
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using ResultOfUnwrapSharedPtr =
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typename UnwrapSharedPtr<invoke_result_t<F>>::type;
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template <typename F>
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using ResultOfUnwrapObserver =
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typename UnwrapObserver<invoke_result_t<F>>::type;
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template <typename T>
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struct Unwrap {
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using type = T;
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};
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template <typename T>
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struct Unwrap<observer::Observer<T>> {
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using type = T;
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};
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} // namespace observer_detail
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} // namespace folly
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