proxygen
gtest-message.h
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29 //
30 // Author: wan@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.
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.
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.
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.
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_
#define T(v)
Definition: http_parser.c:233
char b
#define GTEST_API_
Definition: gtest-port.h:934
STL namespace.
double val
Definition: String.cpp:273
std::ostream & operator<<(std::ostream &os, const Message &sb)
Message(const char *str)
Message(const Message &msg)
Definition: gtest-message.h:96
std::string StreamableToString(const T &streamable)
void operator<<(const testing::internal::Secret &, int)
::std::wstring wstring
Definition: gtest-port.h:1103
std::string GetString() const
Definition: gtest.cc:981
static const char *const value
Definition: Conv.cpp:50
const char * string
Definition: Conv.cpp:212