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30 // The Google C++ Testing and Mocking Framework (Google Test)
32 // This header file defines the Message class.
34 // IMPORTANT NOTE: Due to limitation of the C++ language, we have to
35 // leave some internal implementation details in this header file.
36 // They are clearly marked by comments like this:
38 // // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
40 // Such code is NOT meant to be used by a user directly, and is subject
41 // to CHANGE WITHOUT NOTICE. Therefore DO NOT DEPEND ON IT in a user
44 // IWYU pragma: private, include "gtest/gtest.h"
45 // IWYU pragma: friend gtest/.*
46 // IWYU pragma: friend gmock/.*
48 #ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_MESSAGE_H_
49 #define GOOGLETEST_INCLUDE_GTEST_GTEST_MESSAGE_H_
57 #include "gtest/internal/gtest-port.h"
60 #include <type_traits>
62 #include "absl/strings/internal/has_absl_stringify.h"
63 #include "absl/strings/str_cat.h"
64 #endif // GTEST_HAS_ABSL
66 GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
67 /* class A needs to have dll-interface to be used by clients of class B */)
69 // Ensures that there is at least one operator<< in the global namespace.
70 // See Message& operator<<(...) below for why.
71 void operator<<(const testing::internal::Secret
&, int);
75 // The Message class works like an ostream repeater.
79 // 1. You stream a bunch of values to a Message object.
80 // It will remember the text in a stringstream.
81 // 2. Then you stream the Message object to an ostream.
82 // This causes the text in the Message to be streamed
87 // testing::Message foo;
88 // foo << 1 << " != " << 2;
91 // will print "1 != 2".
93 // Message is not intended to be inherited from. In particular, its
94 // destructor is not virtual.
96 // Note that stringstream behaves differently in gcc and in MSVC. You
97 // can stream a NULL char pointer to it in the former, but not in the
98 // latter (it causes an access violation if you do). The Message
99 // class hides this difference by treating a NULL char pointer as
101 class GTEST_API_ Message
{
103 // The type of basic IO manipulators (endl, ends, and flush) for
105 typedef std::ostream
& (*BasicNarrowIoManip
)(std::ostream
&);
108 // Constructs an empty Message.
112 Message(const Message
& msg
) : ss_(new ::std::stringstream
) { // NOLINT
113 *ss_
<< msg
.GetString();
116 // Constructs a Message from a C-string.
117 explicit Message(const char* str
) : ss_(new ::std::stringstream
) {
121 // Streams a non-pointer value to this object. If building a version of
122 // GoogleTest with ABSL, this overload is only enabled if the value does not
123 // have an AbslStringify definition.
125 #ifdef GTEST_HAS_ABSL
127 typename
std::enable_if
<
128 !absl::strings_internal::HasAbslStringify
<T
>::value
, // NOLINT
130 #endif // GTEST_HAS_ABSL
132 inline Message
& operator<<(const T
& val
) {
133 // Some libraries overload << for STL containers. These
134 // overloads are defined in the global namespace instead of ::std.
136 // C++'s symbol lookup rule (i.e. Koenig lookup) says that these
137 // overloads are visible in either the std namespace or the global
138 // namespace, but not other namespaces, including the testing
139 // namespace which Google Test's Message class is in.
141 // To allow STL containers (and other types that has a << operator
142 // defined in the global namespace) to be used in Google Test
143 // assertions, testing::Message must access the custom << operator
144 // from the global namespace. With this using declaration,
145 // overloads of << defined in the global namespace and those
146 // visible via Koenig lookup are both exposed in this function.
148 // LLVM local change to support llvm printables.
151 *ss_
<< llvm_gtest::printable(val
);
152 // LLVM local change end.
156 #ifdef GTEST_HAS_ABSL
157 // Streams a non-pointer value with an AbslStringify definition to this
159 template <typename T
,
160 typename
std::enable_if
<
161 absl::strings_internal::HasAbslStringify
<T
>::value
, // NOLINT
163 inline Message
& operator<<(const T
& val
) {
164 // ::operator<< is needed here for a similar reason as with the non-Abseil
167 *ss_
<< absl::StrCat(val
);
170 #endif // GTEST_HAS_ABSL
172 // Streams a pointer value to this object.
174 // This function is an overload of the previous one. When you
175 // stream a pointer to a Message, this definition will be used as it
176 // is more specialized. (The C++ Standard, section
177 // [temp.func.order].) If you stream a non-pointer, then the
178 // previous definition will be used.
180 // The reason for this overload is that streaming a NULL pointer to
181 // ostream is undefined behavior. Depending on the compiler, you
182 // may get "0", "(nil)", "(null)", or an access violation. To
183 // ensure consistent result across compilers, we always treat NULL
185 template <typename T
>
186 inline Message
& operator<<(T
* const& pointer
) { // NOLINT
187 if (pointer
== nullptr) {
190 // LLVM local change to support llvm printables.
193 *ss_
<< llvm_gtest::printable(pointer
);
194 // LLVM local change end.
199 // Since the basic IO manipulators are overloaded for both narrow
200 // and wide streams, we have to provide this specialized definition
201 // of operator <<, even though its body is the same as the
202 // templatized version above. Without this definition, streaming
203 // endl or other basic IO manipulators to Message will confuse the
205 Message
& operator<<(BasicNarrowIoManip val
) {
210 // Instead of 1/0, we want to see true/false for bool values.
211 Message
& operator<<(bool b
) { return *this << (b
? "true" : "false"); }
213 // These two overloads allow streaming a wide C string to a Message
214 // using the UTF-8 encoding.
215 Message
& operator<<(const wchar_t* wide_c_str
);
216 Message
& operator<<(wchar_t* wide_c_str
);
218 #if GTEST_HAS_STD_WSTRING
219 // Converts the given wide string to a narrow string using the UTF-8
220 // encoding, and streams the result to this Message object.
221 Message
& operator<<(const ::std::wstring
& wstr
);
222 #endif // GTEST_HAS_STD_WSTRING
224 // Gets the text streamed to this object so far as an std::string.
225 // Each '\0' character in the buffer is replaced with "\\0".
227 // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
228 std::string
GetString() const;
231 // We'll hold the text streamed to this object here.
232 const std::unique_ptr
< ::std::stringstream
> ss_
;
234 // We declare (but don't implement) this to prevent the compiler
235 // from implementing the assignment operator.
236 void operator=(const Message
&);
239 // Streams a Message to an ostream.
240 inline std::ostream
& operator<<(std::ostream
& os
, const Message
& sb
) {
241 return os
<< sb
.GetString();
246 // Converts a streamable value to an std::string. A NULL pointer is
247 // converted to "(null)". When the input value is a ::string,
248 // ::std::string, ::wstring, or ::std::wstring object, each NUL
249 // character in it is replaced with "\\0".
250 template <typename T
>
251 std::string
StreamableToString(const T
& streamable
) {
252 return (Message() << streamable
).GetString();
255 } // namespace internal
256 } // namespace testing
258 GTEST_DISABLE_MSC_WARNINGS_POP_() // 4251
260 #endif // GOOGLETEST_INCLUDE_GTEST_GTEST_MESSAGE_H_