Line data    Source code

       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             : {
      22             :   AlignedStorage2<T> mStorage;
      23             : 
      24             :   // Copy construction can't be supported because C++ requires that any enclosed
      25             :   // T be initialized in a way C++ knows about -- that is, by |new| or similar.
      26             :   UnionMember(const UnionMember&) = delete;
      27             : 
      28             : public:
      29             :   UnionMember() = default;
      30             :   ~UnionMember() = default;
      31             : 
      32         324 :   T& SetValue()
      33             :   {
      34         324 :     new (mStorage.addr()) T();
      35         324 :     return *mStorage.addr();
      36             :   }
      37             :   template <typename T1>
      38           0 :   T& SetValue(const T1& aValue)
      39             :   {
      40           0 :     new (mStorage.addr()) T(aValue);
      41           0 :     return *mStorage.addr();
      42             :   }
      43             :   template<typename T1, typename T2>
      44           0 :   T& SetValue(const T1& aValue1, const T2& aValue2)
      45             :   {
      46           0 :     new (mStorage.addr()) T(aValue1, aValue2);
      47           0 :     return *mStorage.addr();
      48             :   }
      49           0 :   T& Value()
      50             :   {
      51           0 :     return *mStorage.addr();
      52             :   }
      53         243 :   const T& Value() const
      54             :   {
      55         243 :     return *mStorage.addr();
      56             :   }
      57         324 :   void Destroy()
      58             :   {
      59         324 :     mStorage.addr()->~T();
      60         324 :   }
      61             : };
      62             : 
      63             : } // namespace dom
      64             : } // namespace mozilla
      65             : 
      66             : #endif // mozilla_dom_UnionMember_h