1 /* 2 3 Copyright (C) 2010 Apple Inc. All rights reserved. 4 5 Redistribution and use in source and binary forms, with or without 6 modification, are permitted provided that the following conditions 7 are met: 8 1. Redistributions of source code must retain the above copyright 9 notice, this list of conditions and the following disclaimer. 10 2. Redistributions in binary form must reproduce the above copyright 11 notice, this list of conditions and the following disclaimer in the 12 documentation and/or other materials provided with the distribution. 13 14 THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY 15 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 16 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 17 DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY 18 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 19 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 20 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 21 ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 23 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 25 */ 26 27 #ifndef NullPtr_h 28 #define NullPtr_h 29 30 // For compilers and standard libraries that do not yet include it, this adds the 31 // nullptr_t type and nullptr object. They are defined in the same namespaces they 32 // would be in compiler and library that had the support. 33 34 #if COMPILER_SUPPORTS(CXX_NULLPTR) || defined(_LIBCPP_VERSION) 35 36 // libstdc++ supports nullptr_t starting with gcc 4.6. STLport doesn't define it. 37 #if (defined(__GLIBCXX__) && __GLIBCXX__ < 20110325) || defined(_STLPORT_VERSION) 38 namespace std { 39 typedef decltype(nullptr) nullptr_t; 40 } 41 #endif 42 43 #else 44 45 #include "wtf/WTFExport.h" 46 47 namespace std { 48 class nullptr_t { 49 public: 50 // Required in order to create const nullptr_t objects without an 51 // explicit initializer in GCC 4.5, a la: 52 // 53 // const std::nullptr_t nullptr; nullptr_t()54 nullptr_t() { } 55 56 // Make nullptr convertible to any pointer type. 57 template<typename T> operator T*() const { return 0; } 58 // Make nullptr convertible to any member pointer type. 59 template<typename C, typename T> operator T C::*() { return 0; } 60 private: 61 // Do not allow taking the address of nullptr. 62 void operator&(); 63 }; 64 } 65 WTF_EXPORT extern const std::nullptr_t nullptr; 66 67 #endif 68 69 #if COMPILER_SUPPORTS(CXX_DELETED_FUNCTIONS) 70 #define WTF_DISALLOW_CONSTRUCTION_FROM_ZERO(ClassName) \ 71 private: \ 72 ClassName(int) = delete 73 #define WTF_DISALLOW_ZERO_ASSIGNMENT(ClassName) \ 74 private: \ 75 ClassName& operator=(int) = delete 76 #else 77 #define WTF_DISALLOW_CONSTRUCTION_FROM_ZERO(ClassName) \ 78 private: \ 79 ClassName(int) 80 #define WTF_DISALLOW_ZERO_ASSIGNMENT(ClassName) \ 81 private: \ 82 ClassName& operator=(int) 83 #endif 84 85 #endif 86