55 lines
1.4 KiB
C++
55 lines
1.4 KiB
C++
/*
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#pragma once
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#include <functional>
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namespace facebook::react::jsinspector_modern {
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/**
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* A template for easily creating empty types that are distinct from one
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* another. Useful if you need to generate marker types for use in an
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* std::variant, and a single std::monostate won't do.
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*/
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template <size_t key>
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struct UniqueMonostate {
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constexpr bool operator==(const UniqueMonostate<key>&) const noexcept {
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return true;
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}
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constexpr bool operator!=(const UniqueMonostate<key>&) const noexcept {
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return false;
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}
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constexpr bool operator<(const UniqueMonostate<key>&) const noexcept {
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return false;
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}
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constexpr bool operator>(const UniqueMonostate<key>&) const noexcept {
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return false;
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}
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constexpr bool operator<=(const UniqueMonostate<key>&) const noexcept {
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return true;
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}
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constexpr bool operator>=(const UniqueMonostate<key>&) const noexcept {
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return true;
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}
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};
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} // namespace facebook::react::jsinspector_modern
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namespace std {
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template <size_t key>
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struct hash<::facebook::react::jsinspector_modern::UniqueMonostate<key>> {
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size_t operator()(
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const ::facebook::react::jsinspector_modern::UniqueMonostate<key>&)
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const noexcept {
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return key;
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}
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};
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} // namespace std
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