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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at */
/* A class for holding the members of a union. */
#ifndef mozilla_dom_UnionMember_h
#define mozilla_dom_UnionMember_h
#include "mozilla/Alignment.h"
#include "mozilla/Attributes.h"
#include <utility>
namespace mozilla::dom {
// The union type has an enum to keep track of which of its UnionMembers has
// been constructed.
template <class T>
class UnionMember {
AlignedStorage2<T> mStorage;
// Copy construction can't be supported because C++ requires that any enclosed
// T be initialized in a way C++ knows about -- that is, by |new| or similar.
UnionMember(const UnionMember&) = delete;
UnionMember() = default;
~UnionMember() = default;
template <typename... Args>
T& SetValue(Args&&... args) {
new (mStorage.addr()) T(std::forward<Args>(args)...);
return *mStorage.addr();
T& Value() { return *mStorage.addr(); }
const T& Value() const { return *mStorage.addr(); }
void Destroy() { mStorage.addr()->~T(); }
} // namespace mozilla::dom
#endif // mozilla_dom_UnionMember_h