| /* |
| * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_METAPROGRAMMING_ENABLEIF_HPP |
| #define SHARE_VM_METAPROGRAMMING_ENABLEIF_HPP |
| |
| #include "memory/allocation.hpp" |
| |
| // This metaprogramming tool allows explicitly enabling and disabling overloads |
| // of member functions depending on whether the condition B holds true. |
| // For example typename EnableIf<IsPointer<T>::value>::type func(T ptr) would |
| // only become an overload the compiler chooses from if the type T is a pointer. |
| // If it is not, then the template definition is not expanded and there will be |
| // no compiler error if there is another overload of func that is selected when |
| // T is not a pointer. Like for example |
| // typename EnableIf<!IsPointer<T>::value>::type func(T not_ptr) |
| |
| template <bool B, typename T = void> |
| struct EnableIf: AllStatic {}; |
| |
| template <typename T> |
| struct EnableIf<true, T>: AllStatic { |
| typedef T type; |
| }; |
| |
| #endif // SHARE_VM_METAPROGRAMMING_ENABLEIF_HPP |
