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29
30//
31// The Google C++ Testing and Mocking Framework (Google Test)
32//
33// This header file defines the Message class.
34//
35// IMPORTANT NOTE: Due to limitation of the C++ language, we have to
36// leave some internal implementation details in this header file.
37// They are clearly marked by comments like this:
38//
39// // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
40//
41// Such code is NOT meant to be used by a user directly, and is subject
42// to CHANGE WITHOUT NOTICE. Therefore DO NOT DEPEND ON IT in a user
43// program!
44
45// GOOGLETEST_CM0001 DO NOT DELETE
46
47#ifndef GTEST_INCLUDE_GTEST_GTEST_MESSAGE_H_
48#define GTEST_INCLUDE_GTEST_GTEST_MESSAGE_H_
49
50#include <limits>
51
52#include "gtest/internal/gtest-port.h"
53
54GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
55/* class A needs to have dll-interface to be used by clients of class B */)
56
57// Ensures that there is at least one operator<< in the global namespace.
58// See Message& operator<<(...) below for why.
59void operator<<(const testing::internal::Secret&, int);
60
61namespace testing {
62
63// The Message class works like an ostream repeater.
64//
65// Typical usage:
66//
67// 1. You stream a bunch of values to a Message object.
68// It will remember the text in a stringstream.
69// 2. Then you stream the Message object to an ostream.
70// This causes the text in the Message to be streamed
71// to the ostream.
72//
73// For example;
74//
75// testing::Message foo;
76// foo << 1 << " != " << 2;
77// std::cout << foo;
78//
79// will print "1 != 2".
80//
81// Message is not intended to be inherited from. In particular, its
82// destructor is not virtual.
83//
84// Note that stringstream behaves differently in gcc and in MSVC. You
85// can stream a NULL char pointer to it in the former, but not in the
86// latter (it causes an access violation if you do). The Message
87// class hides this difference by treating a NULL char pointer as
88// "(null)".
89class GTEST_API_ Message {
90 private:
91 // The type of basic IO manipulators (endl, ends, and flush) for
92 // narrow streams.
93 typedef std::ostream& (*BasicNarrowIoManip)(std::ostream&);
94
95 public:
96 // Constructs an empty Message.
97 Message();
98
99 // Copy constructor.
100 Message(const Message& msg) : ss_(new ::std::stringstream) { // NOLINT
101 *ss_ << msg.GetString();
102 }
103
104 // Constructs a Message from a C-string.
105 explicit Message(const char* str) : ss_(new ::std::stringstream) {
106 *ss_ << str;
107 }
108
109#if GTEST_OS_SYMBIAN
110 // Streams a value (either a pointer or not) to this object.
111 template <typename T>
112 inline Message& operator <<(const T& value) {
113 StreamHelper(typename internal::is_pointer<T>::type(), value);
114 return *this;
115 }
116#else
117 // Streams a non-pointer value to this object.
118 template <typename T>
119 inline Message& operator <<(const T& val) {
120 // Some libraries overload << for STL containers. These
121 // overloads are defined in the global namespace instead of ::std.
122 //
123 // C++'s symbol lookup rule (i.e. Koenig lookup) says that these
124 // overloads are visible in either the std namespace or the global
125 // namespace, but not other namespaces, including the testing
126 // namespace which Google Test's Message class is in.
127 //
128 // To allow STL containers (and other types that has a << operator
129 // defined in the global namespace) to be used in Google Test
130 // assertions, testing::Message must access the custom << operator
131 // from the global namespace. With this using declaration,
132 // overloads of << defined in the global namespace and those
133 // visible via Koenig lookup are both exposed in this function.
134 using ::operator <<;
135 *ss_ << val;
136 return *this;
137 }
138
139 // Streams a pointer value to this object.
140 //
141 // This function is an overload of the previous one. When you
142 // stream a pointer to a Message, this definition will be used as it
143 // is more specialized. (The C++ Standard, section
144 // [temp.func.order].) If you stream a non-pointer, then the
145 // previous definition will be used.
146 //
147 // The reason for this overload is that streaming a NULL pointer to
148 // ostream is undefined behavior. Depending on the compiler, you
149 // may get "0", "(nil)", "(null)", or an access violation. To
150 // ensure consistent result across compilers, we always treat NULL
151 // as "(null)".
152 template <typename T>
153 inline Message& operator <<(T* const& pointer) { // NOLINT
154 if (pointer == NULL) {
155 *ss_ << "(null)";
156 } else {
157 *ss_ << pointer;
158 }
159 return *this;
160 }
161#endif // GTEST_OS_SYMBIAN
162
163 // Since the basic IO manipulators are overloaded for both narrow
164 // and wide streams, we have to provide this specialized definition
165 // of operator <<, even though its body is the same as the
166 // templatized version above. Without this definition, streaming
167 // endl or other basic IO manipulators to Message will confuse the
168 // compiler.
169 Message& operator <<(BasicNarrowIoManip val) {
170 *ss_ << val;
171 return *this;
172 }
173
174 // Instead of 1/0, we want to see true/false for bool values.
175 Message& operator <<(bool b) {
176 return *this << (b ? "true" : "false");
177 }
178
179 // These two overloads allow streaming a wide C string to a Message
180 // using the UTF-8 encoding.
181 Message& operator <<(const wchar_t* wide_c_str);
182 Message& operator <<(wchar_t* wide_c_str);
183
184#if GTEST_HAS_STD_WSTRING
185 // Converts the given wide string to a narrow string using the UTF-8
186 // encoding, and streams the result to this Message object.
187 Message& operator <<(const ::std::wstring& wstr);
188#endif // GTEST_HAS_STD_WSTRING
189
190#if GTEST_HAS_GLOBAL_WSTRING
191 // Converts the given wide string to a narrow string using the UTF-8
192 // encoding, and streams the result to this Message object.
193 Message& operator <<(const ::wstring& wstr);
194#endif // GTEST_HAS_GLOBAL_WSTRING
195
196 // Gets the text streamed to this object so far as an std::string.
197 // Each '\0' character in the buffer is replaced with "\\0".
198 //
199 // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
200 std::string GetString() const;
201
202 private:
203#if GTEST_OS_SYMBIAN
204 // These are needed as the Nokia Symbian Compiler cannot decide between
205 // const T& and const T* in a function template. The Nokia compiler _can_
206 // decide between class template specializations for T and T*, so a
207 // tr1::type_traits-like is_pointer works, and we can overload on that.
208 template <typename T>
209 inline void StreamHelper(internal::true_type /*is_pointer*/, T* pointer) {
210 if (pointer == NULL) {
211 *ss_ << "(null)";
212 } else {
213 *ss_ << pointer;
214 }
215 }
216 template <typename T>
217 inline void StreamHelper(internal::false_type /*is_pointer*/,
218 const T& value) {
219 // See the comments in Message& operator <<(const T&) above for why
220 // we need this using statement.
221 using ::operator <<;
222 *ss_ << value;
223 }
224#endif // GTEST_OS_SYMBIAN
225
226 // We'll hold the text streamed to this object here.
227 const internal::scoped_ptr< ::std::stringstream> ss_;
228
229 // We declare (but don't implement) this to prevent the compiler
230 // from implementing the assignment operator.
231 void operator=(const Message&);
232};
233
234// Streams a Message to an ostream.
235inline std::ostream& operator <<(std::ostream& os, const Message& sb) {
236 return os << sb.GetString();
237}
238
239namespace internal {
240
241// Converts a streamable value to an std::string. A NULL pointer is
242// converted to "(null)". When the input value is a ::string,
243// ::std::string, ::wstring, or ::std::wstring object, each NUL
244// character in it is replaced with "\\0".
245template <typename T>
246std::string StreamableToString(const T& streamable) {
247 return (Message() << streamable).GetString();
248}
249
250} // namespace internal
251} // namespace testing
252
253GTEST_DISABLE_MSC_WARNINGS_POP_() // 4251
254
255#endif // GTEST_INCLUDE_GTEST_GTEST_MESSAGE_H_
256