1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ 2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */ 3 /* This Source Code Form is subject to the terms of the Mozilla Public 4 * License, v. 2.0. If a copy of the MPL was not distributed with this 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 6 7 /* A class for holding the members of a union. */ 8 9 #ifndef mozilla_dom_UnionMember_h 10 #define mozilla_dom_UnionMember_h 11 12 #include "mozilla/Alignment.h" 13 14 namespace mozilla { 15 namespace dom { 16 17 // The union type has an enum to keep track of which of its UnionMembers has 18 // been constructed. 19 template <class T> 20 class UnionMember { 21 AlignedStorage2<T> mStorage; 22 23 // Copy construction can't be supported because C++ requires that any enclosed 24 // T be initialized in a way C++ knows about -- that is, by |new| or similar. 25 UnionMember(const UnionMember&) = delete; 26 27 public: 28 UnionMember() = default; 29 ~UnionMember() = default; 30 SetValue()31 T& SetValue() { 32 new (mStorage.addr()) T(); 33 return *mStorage.addr(); 34 } 35 template <typename T1> SetValue(const T1 & aValue)36 T& SetValue(const T1& aValue) { 37 new (mStorage.addr()) T(aValue); 38 return *mStorage.addr(); 39 } 40 template <typename T1, typename T2> SetValue(const T1 & aValue1,const T2 & aValue2)41 T& SetValue(const T1& aValue1, const T2& aValue2) { 42 new (mStorage.addr()) T(aValue1, aValue2); 43 return *mStorage.addr(); 44 } Value()45 T& Value() { return *mStorage.addr(); } Value()46 const T& Value() const { return *mStorage.addr(); } Destroy()47 void Destroy() { mStorage.addr()->~T(); } 48 }; 49 50 } // namespace dom 51 } // namespace mozilla 52 53 #endif // mozilla_dom_UnionMember_h 54