1 // Copyright 2005, Google Inc. 2 // 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 names of its 15 // contributors may be used to endorse or promote products derived from 16 // this software without specific prior written permission. 17 // 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 // 30 // Author: wan (at) google.com (Zhanyong Wan) 31 // 32 // The Google C++ Testing Framework (Google Test) 33 // 34 // This header file defines the Message class. 35 // 36 // IMPORTANT NOTE: Due to limitation of the C++ language, we have to 37 // leave some internal implementation details in this header file. 38 // They are clearly marked by comments like this: 39 // 40 // // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM. 41 // 42 // Such code is NOT meant to be used by a user directly, and is subject 43 // to CHANGE WITHOUT NOTICE. Therefore DO NOT DEPEND ON IT in a user 44 // program! 45 46 #ifndef GTEST_INCLUDE_GTEST_GTEST_MESSAGE_H_ 47 #define GTEST_INCLUDE_GTEST_GTEST_MESSAGE_H_ 48 49 #include <limits> 50 51 #include "gtest/internal/gtest-port.h" 52 53 // Ensures that there is at least one operator<< in the global namespace. 54 // See Message& operator<<(...) below for why. 55 void operator<<(const testing::internal::Secret&, int); 56 57 namespace testing { 58 59 // The Message class works like an ostream repeater. 60 // 61 // Typical usage: 62 // 63 // 1. You stream a bunch of values to a Message object. 64 // It will remember the text in a stringstream. 65 // 2. Then you stream the Message object to an ostream. 66 // This causes the text in the Message to be streamed 67 // to the ostream. 68 // 69 // For example; 70 // 71 // testing::Message foo; 72 // foo << 1 << " != " << 2; 73 // std::cout << foo; 74 // 75 // will print "1 != 2". 76 // 77 // Message is not intended to be inherited from. In particular, its 78 // destructor is not virtual. 79 // 80 // Note that stringstream behaves differently in gcc and in MSVC. You 81 // can stream a NULL char pointer to it in the former, but not in the 82 // latter (it causes an access violation if you do). The Message 83 // class hides this difference by treating a NULL char pointer as 84 // "(null)". 85 class GTEST_API_ Message { 86 private: 87 // The type of basic IO manipulators (endl, ends, and flush) for 88 // narrow streams. 89 typedef std::ostream& (*BasicNarrowIoManip)(std::ostream&); 90 91 public: 92 // Constructs an empty Message. 93 Message(); 94 95 // Copy constructor. 96 Message(const Message& msg) : ss_(new ::std::stringstream) { // NOLINT 97 *ss_ << msg.GetString(); 98 } 99 100 // Constructs a Message from a C-string. 101 explicit Message(const char* str) : ss_(new ::std::stringstream) { 102 *ss_ << str; 103 } 104 105 #if GTEST_OS_SYMBIAN 106 // Streams a value (either a pointer or not) to this object. 107 template <typename T> 108 inline Message& operator <<(const T& value) { 109 StreamHelper(typename internal::is_pointer<T>::type(), value); 110 return *this; 111 } 112 #else 113 // Streams a non-pointer value to this object. 114 template <typename T> 115 inline Message& operator <<(const T& val) { 116 // Some libraries overload << for STL containers. These 117 // overloads are defined in the global namespace instead of ::std. 118 // 119 // C++'s symbol lookup rule (i.e. Koenig lookup) says that these 120 // overloads are visible in either the std namespace or the global 121 // namespace, but not other namespaces, including the testing 122 // namespace which Google Test's Message class is in. 123 // 124 // To allow STL containers (and other types that has a << operator 125 // defined in the global namespace) to be used in Google Test 126 // assertions, testing::Message must access the custom << operator 127 // from the global namespace. With this using declaration, 128 // overloads of << defined in the global namespace and those 129 // visible via Koenig lookup are both exposed in this function. 130 using ::operator <<; 131 *ss_ << val; 132 return *this; 133 } 134 135 // Streams a pointer value to this object. 136 // 137 // This function is an overload of the previous one. When you 138 // stream a pointer to a Message, this definition will be used as it 139 // is more specialized. (The C++ Standard, section 140 // [temp.func.order].) If you stream a non-pointer, then the 141 // previous definition will be used. 142 // 143 // The reason for this overload is that streaming a NULL pointer to 144 // ostream is undefined behavior. Depending on the compiler, you 145 // may get "0", "(nil)", "(null)", or an access violation. To 146 // ensure consistent result across compilers, we always treat NULL 147 // as "(null)". 148 template <typename T> 149 inline Message& operator <<(T* const& pointer) { // NOLINT 150 if (pointer == NULL) { 151 *ss_ << "(null)"; 152 } else { 153 *ss_ << pointer; 154 } 155 return *this; 156 } 157 #endif // GTEST_OS_SYMBIAN 158 159 // Since the basic IO manipulators are overloaded for both narrow 160 // and wide streams, we have to provide this specialized definition 161 // of operator <<, even though its body is the same as the 162 // templatized version above. Without this definition, streaming 163 // endl or other basic IO manipulators to Message will confuse the 164 // compiler. 165 Message& operator <<(BasicNarrowIoManip val) { 166 *ss_ << val; 167 return *this; 168 } 169 170 // Instead of 1/0, we want to see true/false for bool values. 171 Message& operator <<(bool b) { 172 return *this << (b ? "true" : "false"); 173 } 174 175 // These two overloads allow streaming a wide C string to a Message 176 // using the UTF-8 encoding. 177 Message& operator <<(const wchar_t* wide_c_str); 178 Message& operator <<(wchar_t* wide_c_str); 179 180 #if GTEST_HAS_STD_WSTRING 181 // Converts the given wide string to a narrow string using the UTF-8 182 // encoding, and streams the result to this Message object. 183 Message& operator <<(const ::std::wstring& wstr); 184 #endif // GTEST_HAS_STD_WSTRING 185 186 #if GTEST_HAS_GLOBAL_WSTRING 187 // Converts the given wide string to a narrow string using the UTF-8 188 // encoding, and streams the result to this Message object. 189 Message& operator <<(const ::wstring& wstr); 190 #endif // GTEST_HAS_GLOBAL_WSTRING 191 192 // Gets the text streamed to this object so far as an std::string. 193 // Each '\0' character in the buffer is replaced with "\\0". 194 // 195 // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM. 196 std::string GetString() const; 197 198 private: 199 200 #if GTEST_OS_SYMBIAN 201 // These are needed as the Nokia Symbian Compiler cannot decide between 202 // const T& and const T* in a function template. The Nokia compiler _can_ 203 // decide between class template specializations for T and T*, so a 204 // tr1::type_traits-like is_pointer works, and we can overload on that. 205 template <typename T> 206 inline void StreamHelper(internal::true_type /*is_pointer*/, T* pointer) { 207 if (pointer == NULL) { 208 *ss_ << "(null)"; 209 } else { 210 *ss_ << pointer; 211 } 212 } 213 template <typename T> 214 inline void StreamHelper(internal::false_type /*is_pointer*/, 215 const T& value) { 216 // See the comments in Message& operator <<(const T&) above for why 217 // we need this using statement. 218 using ::operator <<; 219 *ss_ << value; 220 } 221 #endif // GTEST_OS_SYMBIAN 222 223 // We'll hold the text streamed to this object here. 224 const internal::scoped_ptr< ::std::stringstream> ss_; 225 226 // We declare (but don't implement) this to prevent the compiler 227 // from implementing the assignment operator. 228 void operator=(const Message&); 229 }; 230 231 // Streams a Message to an ostream. 232 inline std::ostream& operator <<(std::ostream& os, const Message& sb) { 233 return os << sb.GetString(); 234 } 235 236 namespace internal { 237 238 // Converts a streamable value to an std::string. A NULL pointer is 239 // converted to "(null)". When the input value is a ::string, 240 // ::std::string, ::wstring, or ::std::wstring object, each NUL 241 // character in it is replaced with "\\0". 242 template <typename T> 243 std::string StreamableToString(const T& streamable) { 244 return (Message() << streamable).GetString(); 245 } 246 247 } // namespace internal 248 } // namespace testing 249 250 #endif // GTEST_INCLUDE_GTEST_GTEST_MESSAGE_H_ 251