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62 lines
2.3 KiB
C++
62 lines
2.3 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* vim: set ts=8 sts=2 et sw=2 tw=80:
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* A type suitable for returning either a value or an error from a function. */
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#ifndef mozilla_ResultVariant_h
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#define mozilla_ResultVariant_h
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#include "mozilla/MaybeStorageBase.h"
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#include "mozilla/Result.h"
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#include "mozilla/Variant.h"
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namespace mozilla::detail {
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template <typename V, typename E>
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class ResultImplementation<V, E, PackingStrategy::Variant> {
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mozilla::Variant<V, E> mStorage;
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public:
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static constexpr PackingStrategy Strategy = PackingStrategy::Variant;
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ResultImplementation(ResultImplementation&&) = default;
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ResultImplementation(const ResultImplementation&) = delete;
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ResultImplementation& operator=(const ResultImplementation&) = delete;
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ResultImplementation& operator=(ResultImplementation&&) = default;
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explicit ResultImplementation(V&& aValue) : mStorage(std::move(aValue)) {}
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explicit ResultImplementation(const V& aValue) : mStorage(aValue) {}
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template <typename... Args>
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explicit ResultImplementation(std::in_place_t, Args&&... aArgs)
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: mStorage(VariantType<V>{}, std::forward<Args>(aArgs)...) {}
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explicit ResultImplementation(const E& aErrorValue) : mStorage(aErrorValue) {}
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explicit ResultImplementation(E&& aErrorValue)
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: mStorage(std::move(aErrorValue)) {}
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bool isOk() const { return mStorage.template is<V>(); }
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// The callers of these functions will assert isOk() has the proper value, so
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// these functions (in all ResultImplementation specializations) don't need
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// to do so.
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V unwrap() { return std::move(mStorage.template as<V>()); }
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const V& inspect() const { return mStorage.template as<V>(); }
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E unwrapErr() { return std::move(mStorage.template as<E>()); }
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const E& inspectErr() const { return mStorage.template as<E>(); }
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void updateAfterTracing(V&& aValue) {
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mStorage.template emplace<V>(std::move(aValue));
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}
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void updateErrorAfterTracing(E&& aErrorValue) {
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mStorage.template emplace<E>(std::move(aErrorValue));
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}
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};
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} // namespace mozilla::detail
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#endif // mozilla_ResultVariant_h
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