1 // Copyright (c) 2014 Marshall A. Greenblatt. Portions copyright (c) 2011 2 // Google Inc. All rights reserved. 3 // 4 // Redistribution and use in source and binary forms, with or without 5 // modification, are permitted provided that the following conditions are 6 // met: 7 // 8 // * Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above 11 // copyright notice, this list of conditions and the following disclaimer 12 // in the documentation and/or other materials provided with the 13 // distribution. 14 // * Neither the name of Google Inc. nor the name Chromium Embedded 15 // Framework nor the names of its contributors may be used to endorse 16 // or promote products derived from this software without specific prior 17 // written permission. 18 // 19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31 #ifndef CEF_INCLUDE_BASE_CEF_TEMPLATE_UTIL_H_ 32 #define CEF_INCLUDE_BASE_CEF_TEMPLATE_UTIL_H_ 33 #pragma once 34 35 #if defined(BASE_TEMPLATE_UTIL_H_) 36 // Do nothing if the Chromium header has already been included. 37 // This can happen in cases where Chromium code is used directly by the 38 // client application. When using Chromium code directly always include 39 // the Chromium header first to avoid type conflicts. 40 #elif defined(USING_CHROMIUM_INCLUDES) 41 // When building CEF include the Chromium header directly. 42 #include "base/template_util.h" 43 #else // !USING_CHROMIUM_INCLUDES 44 // The following is substantially similar to the Chromium implementation. 45 // If the Chromium implementation diverges the below implementation should be 46 // updated to match. 47 48 #include <cstddef> // For size_t. 49 50 #include "include/base/cef_build.h" 51 52 namespace base { 53 54 // template definitions from tr1 55 56 template <class T, T v> 57 struct integral_constant { 58 static const T value = v; 59 typedef T value_type; 60 typedef integral_constant<T, v> type; 61 }; 62 63 template <class T, T v> 64 const T integral_constant<T, v>::value; 65 66 typedef integral_constant<bool, true> true_type; 67 typedef integral_constant<bool, false> false_type; 68 69 template <class T> 70 struct is_pointer : false_type {}; 71 template <class T> 72 struct is_pointer<T*> : true_type {}; 73 74 // Member function pointer detection up to four params. Add more as needed 75 // below. This is built-in to C++ 11, and we can remove this when we switch. 76 template <typename T> 77 struct is_member_function_pointer : false_type {}; 78 79 template <typename R, typename Z> 80 struct is_member_function_pointer<R (Z::*)()> : true_type {}; 81 template <typename R, typename Z> 82 struct is_member_function_pointer<R (Z::*)() const> : true_type {}; 83 84 template <typename R, typename Z, typename A> 85 struct is_member_function_pointer<R (Z::*)(A)> : true_type {}; 86 template <typename R, typename Z, typename A> 87 struct is_member_function_pointer<R (Z::*)(A) const> : true_type {}; 88 89 template <typename R, typename Z, typename A, typename B> 90 struct is_member_function_pointer<R (Z::*)(A, B)> : true_type {}; 91 template <typename R, typename Z, typename A, typename B> 92 struct is_member_function_pointer<R (Z::*)(A, B) const> : true_type {}; 93 94 template <typename R, typename Z, typename A, typename B, typename C> 95 struct is_member_function_pointer<R (Z::*)(A, B, C)> : true_type {}; 96 template <typename R, typename Z, typename A, typename B, typename C> 97 struct is_member_function_pointer<R (Z::*)(A, B, C) const> : true_type {}; 98 99 template <typename R, 100 typename Z, 101 typename A, 102 typename B, 103 typename C, 104 typename D> 105 struct is_member_function_pointer<R (Z::*)(A, B, C, D)> : true_type {}; 106 template <typename R, 107 typename Z, 108 typename A, 109 typename B, 110 typename C, 111 typename D> 112 struct is_member_function_pointer<R (Z::*)(A, B, C, D) const> : true_type {}; 113 114 template <class T, class U> 115 struct is_same : public false_type {}; 116 template <class T> 117 struct is_same<T, T> : true_type {}; 118 119 template <class> 120 struct is_array : public false_type {}; 121 template <class T, size_t n> 122 struct is_array<T[n]> : public true_type {}; 123 template <class T> 124 struct is_array<T[]> : public true_type {}; 125 126 template <class T> 127 struct is_non_const_reference : false_type {}; 128 template <class T> 129 struct is_non_const_reference<T&> : true_type {}; 130 template <class T> 131 struct is_non_const_reference<const T&> : false_type {}; 132 133 template <class T> 134 struct is_const : false_type {}; 135 template <class T> 136 struct is_const<const T> : true_type {}; 137 138 template <class T> 139 struct is_void : false_type {}; 140 template <> 141 struct is_void<void> : true_type {}; 142 143 namespace cef_internal { 144 145 // Types YesType and NoType are guaranteed such that sizeof(YesType) < 146 // sizeof(NoType). 147 typedef char YesType; 148 149 struct NoType { 150 YesType dummy[2]; 151 }; 152 153 // This class is an implementation detail for is_convertible, and you 154 // don't need to know how it works to use is_convertible. For those 155 // who care: we declare two different functions, one whose argument is 156 // of type To and one with a variadic argument list. We give them 157 // return types of different size, so we can use sizeof to trick the 158 // compiler into telling us which function it would have chosen if we 159 // had called it with an argument of type From. See Alexandrescu's 160 // _Modern C++ Design_ for more details on this sort of trick. 161 162 struct ConvertHelper { 163 template <typename To> 164 static YesType Test(To); 165 166 template <typename To> 167 static NoType Test(...); 168 169 template <typename From> 170 static From& Create(); 171 }; 172 173 // Used to determine if a type is a struct/union/class. Inspired by Boost's 174 // is_class type_trait implementation. 175 struct IsClassHelper { 176 template <typename C> 177 static YesType Test(void (C::*)(void)); 178 179 template <typename C> 180 static NoType Test(...); 181 }; 182 183 } // namespace cef_internal 184 185 // Inherits from true_type if From is convertible to To, false_type otherwise. 186 // 187 // Note that if the type is convertible, this will be a true_type REGARDLESS 188 // of whether or not the conversion would emit a warning. 189 template <typename From, typename To> 190 struct is_convertible 191 : integral_constant<bool, 192 sizeof(cef_internal::ConvertHelper::Test<To>( 193 cef_internal::ConvertHelper::Create<From>())) == 194 sizeof(cef_internal::YesType)> {}; 195 196 template <typename T> 197 struct is_class 198 : integral_constant<bool, 199 sizeof(cef_internal::IsClassHelper::Test<T>(0)) == 200 sizeof(cef_internal::YesType)> {}; 201 202 template <bool B, class T = void> 203 struct enable_if {}; 204 205 template <class T> 206 struct enable_if<true, T> { 207 typedef T type; 208 }; 209 210 } // namespace base 211 212 #endif // !USING_CHROMIUM_INCLUDES 213 214 #endif // CEF_INCLUDE_BASE_CEF_TEMPLATE_UTIL_H_ 215