287c948845
God damned C++ template.
41 lines
1 KiB
C++
41 lines
1 KiB
C++
// Copyright (c) 2013 GitHub, Inc. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
#ifndef ATOM_COMMON_SWAP_OR_ASSIGN_H_
|
|
#define ATOM_COMMON_SWAP_OR_ASSIGN_H_
|
|
|
|
namespace internal {
|
|
|
|
// Helper to detect whether value has specified method.
|
|
template <typename T>
|
|
class HasSwapMethod {
|
|
typedef char one;
|
|
typedef long two;
|
|
template <typename C> static one test(char[sizeof(&C::swap)]) ;
|
|
template <typename C> static two test(...);
|
|
public:
|
|
enum { value = sizeof(test<T>(0)) == sizeof(char) };
|
|
};
|
|
|
|
template<bool B, class T = void>
|
|
struct enable_if {};
|
|
|
|
template<class T>
|
|
struct enable_if<true, T> { typedef T type; };
|
|
|
|
template<typename T>
|
|
typename enable_if<HasSwapMethod<T>::value>::type SwapOrAssign(
|
|
T& v1, const T& v2) {
|
|
v1.swap(const_cast<T&>(v2));
|
|
}
|
|
|
|
template<typename T>
|
|
typename enable_if<!HasSwapMethod<T>::value>::type SwapOrAssign(
|
|
T& v1, const T& v2) {
|
|
v1 = v2;
|
|
}
|
|
|
|
} // namespace internal
|
|
|
|
#endif // ATOM_COMMON_SWAP_OR_ASSIGN_H_
|