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1 // Copyright 2007, 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
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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 
31 // Google Test - The Google C++ Testing and Mocking Framework
32 //
33 // This file implements a universal value printer that can print a
34 // value of any type T:
35 //
36 //   void ::testing::internal::UniversalPrinter<T>::Print(value, ostream_ptr);
37 //
38 // A user can teach this function how to print a class type T by
39 // defining either operator<<() or PrintTo() in the namespace that
40 // defines T.  More specifically, the FIRST defined function in the
41 // following list will be used (assuming T is defined in namespace
42 // foo):
43 //
44 //   1. foo::PrintTo(const T&, ostream*)
45 //   2. operator<<(ostream&, const T&) defined in either foo or the
46 //      global namespace.
47 //
48 // However if T is an STL-style container then it is printed element-wise
49 // unless foo::PrintTo(const T&, ostream*) is defined. Note that
50 // operator<<() is ignored for container types.
51 //
52 // If none of the above is defined, it will print the debug string of
53 // the value if it is a protocol buffer, or print the raw bytes in the
54 // value otherwise.
55 //
56 // To aid debugging: when T is a reference type, the address of the
57 // value is also printed; when T is a (const) char pointer, both the
58 // pointer value and the NUL-terminated string it points to are
59 // printed.
60 //
61 // We also provide some convenient wrappers:
62 //
63 //   // Prints a value to a string.  For a (const or not) char
64 //   // pointer, the NUL-terminated string (but not the pointer) is
65 //   // printed.
66 //   std::string ::testing::PrintToString(const T& value);
67 //
68 //   // Prints a value tersely: for a reference type, the referenced
69 //   // value (but not the address) is printed; for a (const or not) char
70 //   // pointer, the NUL-terminated string (but not the pointer) is
71 //   // printed.
72 //   void ::testing::internal::UniversalTersePrint(const T& value, ostream*);
73 //
74 //   // Prints value using the type inferred by the compiler.  The difference
75 //   // from UniversalTersePrint() is that this function prints both the
76 //   // pointer and the NUL-terminated string for a (const or not) char pointer.
77 //   void ::testing::internal::UniversalPrint(const T& value, ostream*);
78 //
79 //   // Prints the fields of a tuple tersely to a string vector, one
80 //   // element for each field. Tuple support must be enabled in
81 //   // gtest-port.h.
82 //   std::vector<string> UniversalTersePrintTupleFieldsToStrings(
83 //       const Tuple& value);
84 //
85 // Known limitation:
86 //
87 // The print primitives print the elements of an STL-style container
88 // using the compiler-inferred type of *iter where iter is a
89 // const_iterator of the container.  When const_iterator is an input
90 // iterator but not a forward iterator, this inferred type may not
91 // match value_type, and the print output may be incorrect.  In
92 // practice, this is rarely a problem as for most containers
93 // const_iterator is a forward iterator.  We'll fix this if there's an
94 // actual need for it.  Note that this fix cannot rely on value_type
95 // being defined as many user-defined container types don't have
96 // value_type.
97 
98 // GOOGLETEST_CM0001 DO NOT DELETE
99 
100 #ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_PRINTERS_H_
101 #define GOOGLETEST_INCLUDE_GTEST_GTEST_PRINTERS_H_
102 
103 #include <functional>
104 #include <memory>
105 #include <ostream>  // NOLINT
106 #include <sstream>
107 #include <string>
108 #include <tuple>
109 #include <type_traits>
110 #include <utility>
111 #include <vector>
112 
113 #include "gtest/internal/gtest-internal.h"
114 #include "gtest/internal/gtest-port.h"
115 
116 namespace testing {
117 
118 // Definitions in the internal* namespaces are subject to change without notice.
119 // DO NOT USE THEM IN USER CODE!
120 namespace internal {
121 
122 template <typename T>
123 void UniversalPrint(const T& value, ::std::ostream* os);
124 
125 // Used to print an STL-style container when the user doesn't define
126 // a PrintTo() for it.
127 struct ContainerPrinter {
128   template <typename T,
129             typename = typename std::enable_if<
130                 (sizeof(IsContainerTest<T>(0)) == sizeof(IsContainer)) &&
131                 !IsRecursiveContainer<T>::value>::type>
PrintValueContainerPrinter132   static void PrintValue(const T& container, std::ostream* os) {
133     const size_t kMaxCount = 32;  // The maximum number of elements to print.
134     *os << '{';
135     size_t count = 0;
136     for (auto&& elem : container) {
137       if (count > 0) {
138         *os << ',';
139         if (count == kMaxCount) {  // Enough has been printed.
140           *os << " ...";
141           break;
142         }
143       }
144       *os << ' ';
145       // We cannot call PrintTo(elem, os) here as PrintTo() doesn't
146       // handle `elem` being a native array.
147       internal::UniversalPrint(elem, os);
148       ++count;
149     }
150 
151     if (count > 0) {
152       *os << ' ';
153     }
154     *os << '}';
155   }
156 };
157 
158 // Used to print a pointer that is neither a char pointer nor a member
159 // pointer, when the user doesn't define PrintTo() for it.  (A member
160 // variable pointer or member function pointer doesn't really point to
161 // a location in the address space.  Their representation is
162 // implementation-defined.  Therefore they will be printed as raw
163 // bytes.)
164 struct FunctionPointerPrinter {
165   template <typename T, typename = typename std::enable_if<
166                             std::is_function<T>::value>::type>
PrintValueFunctionPointerPrinter167   static void PrintValue(T* p, ::std::ostream* os) {
168     if (p == nullptr) {
169       *os << "NULL";
170     } else {
171       // T is a function type, so '*os << p' doesn't do what we want
172       // (it just prints p as bool).  We want to print p as a const
173       // void*.
174       *os << reinterpret_cast<const void*>(p);
175     }
176   }
177 };
178 
179 struct PointerPrinter {
180   template <typename T>
PrintValuePointerPrinter181   static void PrintValue(T* p, ::std::ostream* os) {
182     if (p == nullptr) {
183       *os << "NULL";
184     } else {
185       // T is not a function type.  We just call << to print p,
186       // relying on ADL to pick up user-defined << for their pointer
187       // types, if any.
188       *os << p;
189     }
190   }
191 };
192 
193 namespace internal_stream_operator_without_lexical_name_lookup {
194 
195 // The presence of an operator<< here will terminate lexical scope lookup
196 // straight away (even though it cannot be a match because of its argument
197 // types). Thus, the two operator<< calls in StreamPrinter will find only ADL
198 // candidates.
199 struct LookupBlocker {};
200 void operator<<(LookupBlocker, LookupBlocker);
201 
202 struct StreamPrinter {
203   template <typename T,
204             // Don't accept member pointers here. We'd print them via implicit
205             // conversion to bool, which isn't useful.
206             typename = typename std::enable_if<
207                 !std::is_member_pointer<T>::value>::type,
208             // Only accept types for which we can find a streaming operator via
209             // ADL (possibly involving implicit conversions).
210             typename = decltype(std::declval<std::ostream&>()
211                                 << std::declval<const T&>())>
PrintValueStreamPrinter212   static void PrintValue(const T& value, ::std::ostream* os) {
213     // Call streaming operator found by ADL, possibly with implicit conversions
214     // of the arguments.
215     *os << value;
216   }
217 };
218 
219 }  // namespace internal_stream_operator_without_lexical_name_lookup
220 
221 struct ProtobufPrinter {
222   // We print a protobuf using its ShortDebugString() when the string
223   // doesn't exceed this many characters; otherwise we print it using
224   // DebugString() for better readability.
225   static const size_t kProtobufOneLinerMaxLength = 50;
226 
227   template <typename T,
228             typename = typename std::enable_if<
229                 internal::HasDebugStringAndShortDebugString<T>::value>::type>
PrintValueProtobufPrinter230   static void PrintValue(const T& value, ::std::ostream* os) {
231     std::string pretty_str = value.ShortDebugString();
232     if (pretty_str.length() > kProtobufOneLinerMaxLength) {
233       pretty_str = "\n" + value.DebugString();
234     }
235     *os << ("<" + pretty_str + ">");
236   }
237 };
238 
239 struct ConvertibleToIntegerPrinter {
240   // Since T has no << operator or PrintTo() but can be implicitly
241   // converted to BiggestInt, we print it as a BiggestInt.
242   //
243   // Most likely T is an enum type (either named or unnamed), in which
244   // case printing it as an integer is the desired behavior.  In case
245   // T is not an enum, printing it as an integer is the best we can do
246   // given that it has no user-defined printer.
PrintValueConvertibleToIntegerPrinter247   static void PrintValue(internal::BiggestInt value, ::std::ostream* os) {
248     *os << value;
249   }
250 };
251 
252 struct ConvertibleToStringViewPrinter {
253 #if GTEST_INTERNAL_HAS_STRING_VIEW
PrintValueConvertibleToStringViewPrinter254   static void PrintValue(internal::StringView value, ::std::ostream* os) {
255     internal::UniversalPrint(value, os);
256   }
257 #endif
258 };
259 
260 
261 // Prints the given number of bytes in the given object to the given
262 // ostream.
263 GTEST_API_ void PrintBytesInObjectTo(const unsigned char* obj_bytes,
264                                      size_t count,
265                                      ::std::ostream* os);
266 struct RawBytesPrinter {
267   // SFINAE on `sizeof` to make sure we have a complete type.
268   template <typename T, size_t = sizeof(T)>
PrintValueRawBytesPrinter269   static void PrintValue(const T& value, ::std::ostream* os) {
270     PrintBytesInObjectTo(
271         static_cast<const unsigned char*>(
272             // Load bearing cast to void* to support iOS
273             reinterpret_cast<const void*>(std::addressof(value))),
274         sizeof(value), os);
275   }
276 };
277 
278 struct FallbackPrinter {
279   template <typename T>
PrintValueFallbackPrinter280   static void PrintValue(const T&, ::std::ostream* os) {
281     *os << "(incomplete type)";
282   }
283 };
284 
285 // Try every printer in order and return the first one that works.
286 template <typename T, typename E, typename Printer, typename... Printers>
287 struct FindFirstPrinter : FindFirstPrinter<T, E, Printers...> {};
288 
289 template <typename T, typename Printer, typename... Printers>
290 struct FindFirstPrinter<
291     T, decltype(Printer::PrintValue(std::declval<const T&>(), nullptr)),
292     Printer, Printers...> {
293   using type = Printer;
294 };
295 
296 // Select the best printer in the following order:
297 //  - Print containers (they have begin/end/etc).
298 //  - Print function pointers.
299 //  - Print object pointers.
300 //  - Use the stream operator, if available.
301 //  - Print protocol buffers.
302 //  - Print types convertible to BiggestInt.
303 //  - Print types convertible to StringView, if available.
304 //  - Fallback to printing the raw bytes of the object.
305 template <typename T>
306 void PrintWithFallback(const T& value, ::std::ostream* os) {
307   using Printer = typename FindFirstPrinter<
308       T, void, ContainerPrinter, FunctionPointerPrinter, PointerPrinter,
309       internal_stream_operator_without_lexical_name_lookup::StreamPrinter,
310       ProtobufPrinter, ConvertibleToIntegerPrinter,
311       ConvertibleToStringViewPrinter, RawBytesPrinter, FallbackPrinter>::type;
312   Printer::PrintValue(value, os);
313 }
314 
315 // FormatForComparison<ToPrint, OtherOperand>::Format(value) formats a
316 // value of type ToPrint that is an operand of a comparison assertion
317 // (e.g. ASSERT_EQ).  OtherOperand is the type of the other operand in
318 // the comparison, and is used to help determine the best way to
319 // format the value.  In particular, when the value is a C string
320 // (char pointer) and the other operand is an STL string object, we
321 // want to format the C string as a string, since we know it is
322 // compared by value with the string object.  If the value is a char
323 // pointer but the other operand is not an STL string object, we don't
324 // know whether the pointer is supposed to point to a NUL-terminated
325 // string, and thus want to print it as a pointer to be safe.
326 //
327 // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
328 
329 // The default case.
330 template <typename ToPrint, typename OtherOperand>
331 class FormatForComparison {
332  public:
333   static ::std::string Format(const ToPrint& value) {
334     return ::testing::PrintToString(value);
335   }
336 };
337 
338 // Array.
339 template <typename ToPrint, size_t N, typename OtherOperand>
340 class FormatForComparison<ToPrint[N], OtherOperand> {
341  public:
342   static ::std::string Format(const ToPrint* value) {
343     return FormatForComparison<const ToPrint*, OtherOperand>::Format(value);
344   }
345 };
346 
347 // By default, print C string as pointers to be safe, as we don't know
348 // whether they actually point to a NUL-terminated string.
349 
350 #define GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(CharType)                \
351   template <typename OtherOperand>                                      \
352   class FormatForComparison<CharType*, OtherOperand> {                  \
353    public:                                                              \
354     static ::std::string Format(CharType* value) {                      \
355       return ::testing::PrintToString(static_cast<const void*>(value)); \
356     }                                                                   \
357   }
358 
359 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(char);
360 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const char);
361 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(wchar_t);
362 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const wchar_t);
363 #ifdef __cpp_char8_t
364 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(char8_t);
365 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const char8_t);
366 #endif
367 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(char16_t);
368 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const char16_t);
369 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(char32_t);
370 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const char32_t);
371 
372 #undef GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_
373 
374 // If a C string is compared with an STL string object, we know it's meant
375 // to point to a NUL-terminated string, and thus can print it as a string.
376 
377 #define GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(CharType, OtherStringType) \
378   template <>                                                           \
379   class FormatForComparison<CharType*, OtherStringType> {               \
380    public:                                                              \
381     static ::std::string Format(CharType* value) {                      \
382       return ::testing::PrintToString(value);                           \
383     }                                                                   \
384   }
385 
386 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char, ::std::string);
387 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char, ::std::string);
388 #ifdef __cpp_char8_t
389 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char8_t, ::std::u8string);
390 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char8_t, ::std::u8string);
391 #endif
392 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char16_t, ::std::u16string);
393 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char16_t, ::std::u16string);
394 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char32_t, ::std::u32string);
395 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char32_t, ::std::u32string);
396 
397 #if GTEST_HAS_STD_WSTRING
398 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(wchar_t, ::std::wstring);
399 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const wchar_t, ::std::wstring);
400 #endif
401 
402 #undef GTEST_IMPL_FORMAT_C_STRING_AS_STRING_
403 
404 // Formats a comparison assertion (e.g. ASSERT_EQ, EXPECT_LT, and etc)
405 // operand to be used in a failure message.  The type (but not value)
406 // of the other operand may affect the format.  This allows us to
407 // print a char* as a raw pointer when it is compared against another
408 // char* or void*, and print it as a C string when it is compared
409 // against an std::string object, for example.
410 //
411 // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
412 template <typename T1, typename T2>
413 std::string FormatForComparisonFailureMessage(
414     const T1& value, const T2& /* other_operand */) {
415   return FormatForComparison<T1, T2>::Format(value);
416 }
417 
418 // UniversalPrinter<T>::Print(value, ostream_ptr) prints the given
419 // value to the given ostream.  The caller must ensure that
420 // 'ostream_ptr' is not NULL, or the behavior is undefined.
421 //
422 // We define UniversalPrinter as a class template (as opposed to a
423 // function template), as we need to partially specialize it for
424 // reference types, which cannot be done with function templates.
425 template <typename T>
426 class UniversalPrinter;
427 
428 // Prints the given value using the << operator if it has one;
429 // otherwise prints the bytes in it.  This is what
430 // UniversalPrinter<T>::Print() does when PrintTo() is not specialized
431 // or overloaded for type T.
432 //
433 // A user can override this behavior for a class type Foo by defining
434 // an overload of PrintTo() in the namespace where Foo is defined.  We
435 // give the user this option as sometimes defining a << operator for
436 // Foo is not desirable (e.g. the coding style may prevent doing it,
437 // or there is already a << operator but it doesn't do what the user
438 // wants).
439 template <typename T>
440 void PrintTo(const T& value, ::std::ostream* os) {
441   internal::PrintWithFallback(value, os);
442 }
443 
444 // The following list of PrintTo() overloads tells
445 // UniversalPrinter<T>::Print() how to print standard types (built-in
446 // types, strings, plain arrays, and pointers).
447 
448 // Overloads for various char types.
449 GTEST_API_ void PrintTo(unsigned char c, ::std::ostream* os);
450 GTEST_API_ void PrintTo(signed char c, ::std::ostream* os);
451 inline void PrintTo(char c, ::std::ostream* os) {
452   // When printing a plain char, we always treat it as unsigned.  This
453   // way, the output won't be affected by whether the compiler thinks
454   // char is signed or not.
455   PrintTo(static_cast<unsigned char>(c), os);
456 }
457 
458 // Overloads for other simple built-in types.
459 inline void PrintTo(bool x, ::std::ostream* os) {
460   *os << (x ? "true" : "false");
461 }
462 
463 // Overload for wchar_t type.
464 // Prints a wchar_t as a symbol if it is printable or as its internal
465 // code otherwise and also as its decimal code (except for L'\0').
466 // The L'\0' char is printed as "L'\\0'". The decimal code is printed
467 // as signed integer when wchar_t is implemented by the compiler
468 // as a signed type and is printed as an unsigned integer when wchar_t
469 // is implemented as an unsigned type.
470 GTEST_API_ void PrintTo(wchar_t wc, ::std::ostream* os);
471 
472 GTEST_API_ void PrintTo(char32_t c, ::std::ostream* os);
473 inline void PrintTo(char16_t c, ::std::ostream* os) {
474   PrintTo(ImplicitCast_<char32_t>(c), os);
475 }
476 #ifdef __cpp_char8_t
477 inline void PrintTo(char8_t c, ::std::ostream* os) {
478   PrintTo(ImplicitCast_<char32_t>(c), os);
479 }
480 #endif
481 
482 // Overloads for C strings.
483 GTEST_API_ void PrintTo(const char* s, ::std::ostream* os);
484 inline void PrintTo(char* s, ::std::ostream* os) {
485   PrintTo(ImplicitCast_<const char*>(s), os);
486 }
487 
488 // signed/unsigned char is often used for representing binary data, so
489 // we print pointers to it as void* to be safe.
490 inline void PrintTo(const signed char* s, ::std::ostream* os) {
491   PrintTo(ImplicitCast_<const void*>(s), os);
492 }
493 inline void PrintTo(signed char* s, ::std::ostream* os) {
494   PrintTo(ImplicitCast_<const void*>(s), os);
495 }
496 inline void PrintTo(const unsigned char* s, ::std::ostream* os) {
497   PrintTo(ImplicitCast_<const void*>(s), os);
498 }
499 inline void PrintTo(unsigned char* s, ::std::ostream* os) {
500   PrintTo(ImplicitCast_<const void*>(s), os);
501 }
502 #ifdef __cpp_char8_t
503 // Overloads for u8 strings.
504 GTEST_API_ void PrintTo(const char8_t* s, ::std::ostream* os);
505 inline void PrintTo(char8_t* s, ::std::ostream* os) {
506   PrintTo(ImplicitCast_<const char8_t*>(s), os);
507 }
508 #endif
509 // Overloads for u16 strings.
510 GTEST_API_ void PrintTo(const char16_t* s, ::std::ostream* os);
511 inline void PrintTo(char16_t* s, ::std::ostream* os) {
512   PrintTo(ImplicitCast_<const char16_t*>(s), os);
513 }
514 // Overloads for u32 strings.
515 GTEST_API_ void PrintTo(const char32_t* s, ::std::ostream* os);
516 inline void PrintTo(char32_t* s, ::std::ostream* os) {
517   PrintTo(ImplicitCast_<const char32_t*>(s), os);
518 }
519 
520 // MSVC can be configured to define wchar_t as a typedef of unsigned
521 // short.  It defines _NATIVE_WCHAR_T_DEFINED when wchar_t is a native
522 // type.  When wchar_t is a typedef, defining an overload for const
523 // wchar_t* would cause unsigned short* be printed as a wide string,
524 // possibly causing invalid memory accesses.
525 #if !defined(_MSC_VER) || defined(_NATIVE_WCHAR_T_DEFINED)
526 // Overloads for wide C strings
527 GTEST_API_ void PrintTo(const wchar_t* s, ::std::ostream* os);
528 inline void PrintTo(wchar_t* s, ::std::ostream* os) {
529   PrintTo(ImplicitCast_<const wchar_t*>(s), os);
530 }
531 #endif
532 
533 // Overload for C arrays.  Multi-dimensional arrays are printed
534 // properly.
535 
536 // Prints the given number of elements in an array, without printing
537 // the curly braces.
538 template <typename T>
539 void PrintRawArrayTo(const T a[], size_t count, ::std::ostream* os) {
540   UniversalPrint(a[0], os);
541   for (size_t i = 1; i != count; i++) {
542     *os << ", ";
543     UniversalPrint(a[i], os);
544   }
545 }
546 
547 // Overloads for ::std::string.
548 GTEST_API_ void PrintStringTo(const ::std::string&s, ::std::ostream* os);
549 inline void PrintTo(const ::std::string& s, ::std::ostream* os) {
550   PrintStringTo(s, os);
551 }
552 
553 // Overloads for ::std::u8string
554 #ifdef __cpp_char8_t
555 GTEST_API_ void PrintU8StringTo(const ::std::u8string& s, ::std::ostream* os);
556 inline void PrintTo(const ::std::u8string& s, ::std::ostream* os) {
557   PrintU8StringTo(s, os);
558 }
559 #endif
560 
561 // Overloads for ::std::u16string
562 GTEST_API_ void PrintU16StringTo(const ::std::u16string& s, ::std::ostream* os);
563 inline void PrintTo(const ::std::u16string& s, ::std::ostream* os) {
564   PrintU16StringTo(s, os);
565 }
566 
567 // Overloads for ::std::u32string
568 GTEST_API_ void PrintU32StringTo(const ::std::u32string& s, ::std::ostream* os);
569 inline void PrintTo(const ::std::u32string& s, ::std::ostream* os) {
570   PrintU32StringTo(s, os);
571 }
572 
573 // Overloads for ::std::wstring.
574 #if GTEST_HAS_STD_WSTRING
575 GTEST_API_ void PrintWideStringTo(const ::std::wstring&s, ::std::ostream* os);
576 inline void PrintTo(const ::std::wstring& s, ::std::ostream* os) {
577   PrintWideStringTo(s, os);
578 }
579 #endif  // GTEST_HAS_STD_WSTRING
580 
581 #if GTEST_INTERNAL_HAS_STRING_VIEW
582 // Overload for internal::StringView.
583 inline void PrintTo(internal::StringView sp, ::std::ostream* os) {
584   PrintTo(::std::string(sp), os);
585 }
586 #endif  // GTEST_INTERNAL_HAS_STRING_VIEW
587 
588 inline void PrintTo(std::nullptr_t, ::std::ostream* os) { *os << "(nullptr)"; }
589 
590 template <typename T>
591 void PrintTo(std::reference_wrapper<T> ref, ::std::ostream* os) {
592   UniversalPrinter<T&>::Print(ref.get(), os);
593 }
594 
595 inline const void* VoidifyPointer(const void* p) { return p; }
596 inline const void* VoidifyPointer(volatile const void* p) {
597   return const_cast<const void*>(p);
598 }
599 
600 template <typename T, typename Ptr>
601 void PrintSmartPointer(const Ptr& ptr, std::ostream* os, char) {
602   if (ptr == nullptr) {
603     *os << "(nullptr)";
604   } else {
605     // We can't print the value. Just print the pointer..
606     *os << "(" << (VoidifyPointer)(ptr.get()) << ")";
607   }
608 }
609 template <typename T, typename Ptr,
610           typename = typename std::enable_if<!std::is_void<T>::value &&
611                                              !std::is_array<T>::value>::type>
612 void PrintSmartPointer(const Ptr& ptr, std::ostream* os, int) {
613   if (ptr == nullptr) {
614     *os << "(nullptr)";
615   } else {
616     *os << "(ptr = " << (VoidifyPointer)(ptr.get()) << ", value = ";
617     UniversalPrinter<T>::Print(*ptr, os);
618     *os << ")";
619   }
620 }
621 
622 template <typename T, typename D>
623 void PrintTo(const std::unique_ptr<T, D>& ptr, std::ostream* os) {
624   (PrintSmartPointer<T>)(ptr, os, 0);
625 }
626 
627 template <typename T>
628 void PrintTo(const std::shared_ptr<T>& ptr, std::ostream* os) {
629   (PrintSmartPointer<T>)(ptr, os, 0);
630 }
631 
632 // Helper function for printing a tuple.  T must be instantiated with
633 // a tuple type.
634 template <typename T>
635 void PrintTupleTo(const T&, std::integral_constant<size_t, 0>,
636                   ::std::ostream*) {}
637 
638 template <typename T, size_t I>
639 void PrintTupleTo(const T& t, std::integral_constant<size_t, I>,
640                   ::std::ostream* os) {
641   PrintTupleTo(t, std::integral_constant<size_t, I - 1>(), os);
642   GTEST_INTENTIONAL_CONST_COND_PUSH_()
643   if (I > 1) {
644     GTEST_INTENTIONAL_CONST_COND_POP_()
645     *os << ", ";
646   }
647   UniversalPrinter<typename std::tuple_element<I - 1, T>::type>::Print(
648       std::get<I - 1>(t), os);
649 }
650 
651 template <typename... Types>
652 void PrintTo(const ::std::tuple<Types...>& t, ::std::ostream* os) {
653   *os << "(";
654   PrintTupleTo(t, std::integral_constant<size_t, sizeof...(Types)>(), os);
655   *os << ")";
656 }
657 
658 // Overload for std::pair.
659 template <typename T1, typename T2>
660 void PrintTo(const ::std::pair<T1, T2>& value, ::std::ostream* os) {
661   *os << '(';
662   // We cannot use UniversalPrint(value.first, os) here, as T1 may be
663   // a reference type.  The same for printing value.second.
664   UniversalPrinter<T1>::Print(value.first, os);
665   *os << ", ";
666   UniversalPrinter<T2>::Print(value.second, os);
667   *os << ')';
668 }
669 
670 // Implements printing a non-reference type T by letting the compiler
671 // pick the right overload of PrintTo() for T.
672 template <typename T>
673 class UniversalPrinter {
674  public:
675   // MSVC warns about adding const to a function type, so we want to
676   // disable the warning.
677   GTEST_DISABLE_MSC_WARNINGS_PUSH_(4180)
678 
679   // Note: we deliberately don't call this PrintTo(), as that name
680   // conflicts with ::testing::internal::PrintTo in the body of the
681   // function.
682   static void Print(const T& value, ::std::ostream* os) {
683     // By default, ::testing::internal::PrintTo() is used for printing
684     // the value.
685     //
686     // Thanks to Koenig look-up, if T is a class and has its own
687     // PrintTo() function defined in its namespace, that function will
688     // be visible here.  Since it is more specific than the generic ones
689     // in ::testing::internal, it will be picked by the compiler in the
690     // following statement - exactly what we want.
691     PrintTo(value, os);
692   }
693 
694   GTEST_DISABLE_MSC_WARNINGS_POP_()
695 };
696 
697 // Remove any const-qualifiers before passing a type to UniversalPrinter.
698 template <typename T>
699 class UniversalPrinter<const T> : public UniversalPrinter<T> {};
700 
701 #if GTEST_INTERNAL_HAS_ANY
702 
703 // Printer for std::any / absl::any
704 
705 template <>
706 class UniversalPrinter<Any> {
707  public:
708   static void Print(const Any& value, ::std::ostream* os) {
709     if (value.has_value()) {
710       *os << "value of type " << GetTypeName(value);
711     } else {
712       *os << "no value";
713     }
714   }
715 
716  private:
717   static std::string GetTypeName(const Any& value) {
718 #if GTEST_HAS_RTTI
719     return internal::GetTypeName(value.type());
720 #else
721     static_cast<void>(value);  // possibly unused
722     return "<unknown_type>";
723 #endif  // GTEST_HAS_RTTI
724   }
725 };
726 
727 #endif  // GTEST_INTERNAL_HAS_ANY
728 
729 #if GTEST_INTERNAL_HAS_OPTIONAL
730 
731 // Printer for std::optional / absl::optional
732 
733 template <typename T>
734 class UniversalPrinter<Optional<T>> {
735  public:
736   static void Print(const Optional<T>& value, ::std::ostream* os) {
737     *os << '(';
738     if (!value) {
739       *os << "nullopt";
740     } else {
741       UniversalPrint(*value, os);
742     }
743     *os << ')';
744   }
745 };
746 
747 #endif  // GTEST_INTERNAL_HAS_OPTIONAL
748 
749 #if GTEST_INTERNAL_HAS_VARIANT
750 
751 // Printer for std::variant / absl::variant
752 
753 template <typename... T>
754 class UniversalPrinter<Variant<T...>> {
755  public:
756   static void Print(const Variant<T...>& value, ::std::ostream* os) {
757     *os << '(';
758 #if GTEST_HAS_ABSL
759     absl::visit(Visitor{os, value.index()}, value);
760 #else
761     std::visit(Visitor{os, value.index()}, value);
762 #endif  // GTEST_HAS_ABSL
763     *os << ')';
764   }
765 
766  private:
767   struct Visitor {
768     template <typename U>
769     void operator()(const U& u) const {
770       *os << "'" << GetTypeName<U>() << "(index = " << index
771           << ")' with value ";
772       UniversalPrint(u, os);
773     }
774     ::std::ostream* os;
775     std::size_t index;
776   };
777 };
778 
779 #endif  // GTEST_INTERNAL_HAS_VARIANT
780 
781 // UniversalPrintArray(begin, len, os) prints an array of 'len'
782 // elements, starting at address 'begin'.
783 template <typename T>
784 void UniversalPrintArray(const T* begin, size_t len, ::std::ostream* os) {
785   if (len == 0) {
786     *os << "{}";
787   } else {
788     *os << "{ ";
789     const size_t kThreshold = 18;
790     const size_t kChunkSize = 8;
791     // If the array has more than kThreshold elements, we'll have to
792     // omit some details by printing only the first and the last
793     // kChunkSize elements.
794     if (len <= kThreshold) {
795       PrintRawArrayTo(begin, len, os);
796     } else {
797       PrintRawArrayTo(begin, kChunkSize, os);
798       *os << ", ..., ";
799       PrintRawArrayTo(begin + len - kChunkSize, kChunkSize, os);
800     }
801     *os << " }";
802   }
803 }
804 // This overload prints a (const) char array compactly.
805 GTEST_API_ void UniversalPrintArray(
806     const char* begin, size_t len, ::std::ostream* os);
807 
808 #ifdef __cpp_char8_t
809 // This overload prints a (const) char8_t array compactly.
810 GTEST_API_ void UniversalPrintArray(const char8_t* begin, size_t len,
811                                     ::std::ostream* os);
812 #endif
813 
814 // This overload prints a (const) char16_t array compactly.
815 GTEST_API_ void UniversalPrintArray(const char16_t* begin, size_t len,
816                                     ::std::ostream* os);
817 
818 // This overload prints a (const) char32_t array compactly.
819 GTEST_API_ void UniversalPrintArray(const char32_t* begin, size_t len,
820                                     ::std::ostream* os);
821 
822 // This overload prints a (const) wchar_t array compactly.
823 GTEST_API_ void UniversalPrintArray(
824     const wchar_t* begin, size_t len, ::std::ostream* os);
825 
826 // Implements printing an array type T[N].
827 template <typename T, size_t N>
828 class UniversalPrinter<T[N]> {
829  public:
830   // Prints the given array, omitting some elements when there are too
831   // many.
832   static void Print(const T (&a)[N], ::std::ostream* os) {
833     UniversalPrintArray(a, N, os);
834   }
835 };
836 
837 // Implements printing a reference type T&.
838 template <typename T>
839 class UniversalPrinter<T&> {
840  public:
841   // MSVC warns about adding const to a function type, so we want to
842   // disable the warning.
843   GTEST_DISABLE_MSC_WARNINGS_PUSH_(4180)
844 
845   static void Print(const T& value, ::std::ostream* os) {
846     // Prints the address of the value.  We use reinterpret_cast here
847     // as static_cast doesn't compile when T is a function type.
848     *os << "@" << reinterpret_cast<const void*>(&value) << " ";
849 
850     // Then prints the value itself.
851     UniversalPrint(value, os);
852   }
853 
854   GTEST_DISABLE_MSC_WARNINGS_POP_()
855 };
856 
857 // Prints a value tersely: for a reference type, the referenced value
858 // (but not the address) is printed; for a (const) char pointer, the
859 // NUL-terminated string (but not the pointer) is printed.
860 
861 template <typename T>
862 class UniversalTersePrinter {
863  public:
864   static void Print(const T& value, ::std::ostream* os) {
865     UniversalPrint(value, os);
866   }
867 };
868 template <typename T>
869 class UniversalTersePrinter<T&> {
870  public:
871   static void Print(const T& value, ::std::ostream* os) {
872     UniversalPrint(value, os);
873   }
874 };
875 template <typename T, size_t N>
876 class UniversalTersePrinter<T[N]> {
877  public:
878   static void Print(const T (&value)[N], ::std::ostream* os) {
879     UniversalPrinter<T[N]>::Print(value, os);
880   }
881 };
882 template <>
883 class UniversalTersePrinter<const char*> {
884  public:
885   static void Print(const char* str, ::std::ostream* os) {
886     if (str == nullptr) {
887       *os << "NULL";
888     } else {
889       UniversalPrint(std::string(str), os);
890     }
891   }
892 };
893 template <>
894 class UniversalTersePrinter<char*> : public UniversalTersePrinter<const char*> {
895 };
896 
897 #ifdef __cpp_char8_t
898 template <>
899 class UniversalTersePrinter<const char8_t*> {
900  public:
901   static void Print(const char8_t* str, ::std::ostream* os) {
902     if (str == nullptr) {
903       *os << "NULL";
904     } else {
905       UniversalPrint(::std::u8string(str), os);
906     }
907   }
908 };
909 template <>
910 class UniversalTersePrinter<char8_t*>
911     : public UniversalTersePrinter<const char8_t*> {};
912 #endif
913 
914 template <>
915 class UniversalTersePrinter<const char16_t*> {
916  public:
917   static void Print(const char16_t* str, ::std::ostream* os) {
918     if (str == nullptr) {
919       *os << "NULL";
920     } else {
921       UniversalPrint(::std::u16string(str), os);
922     }
923   }
924 };
925 template <>
926 class UniversalTersePrinter<char16_t*>
927     : public UniversalTersePrinter<const char16_t*> {};
928 
929 template <>
930 class UniversalTersePrinter<const char32_t*> {
931  public:
932   static void Print(const char32_t* str, ::std::ostream* os) {
933     if (str == nullptr) {
934       *os << "NULL";
935     } else {
936       UniversalPrint(::std::u32string(str), os);
937     }
938   }
939 };
940 template <>
941 class UniversalTersePrinter<char32_t*>
942     : public UniversalTersePrinter<const char32_t*> {};
943 
944 #if GTEST_HAS_STD_WSTRING
945 template <>
946 class UniversalTersePrinter<const wchar_t*> {
947  public:
948   static void Print(const wchar_t* str, ::std::ostream* os) {
949     if (str == nullptr) {
950       *os << "NULL";
951     } else {
952       UniversalPrint(::std::wstring(str), os);
953     }
954   }
955 };
956 #endif
957 
958 template <>
959 class UniversalTersePrinter<wchar_t*> {
960  public:
961   static void Print(wchar_t* str, ::std::ostream* os) {
962     UniversalTersePrinter<const wchar_t*>::Print(str, os);
963   }
964 };
965 
966 template <typename T>
967 void UniversalTersePrint(const T& value, ::std::ostream* os) {
968   UniversalTersePrinter<T>::Print(value, os);
969 }
970 
971 // Prints a value using the type inferred by the compiler.  The
972 // difference between this and UniversalTersePrint() is that for a
973 // (const) char pointer, this prints both the pointer and the
974 // NUL-terminated string.
975 template <typename T>
976 void UniversalPrint(const T& value, ::std::ostream* os) {
977   // A workarond for the bug in VC++ 7.1 that prevents us from instantiating
978   // UniversalPrinter with T directly.
979   typedef T T1;
980   UniversalPrinter<T1>::Print(value, os);
981 }
982 
983 typedef ::std::vector< ::std::string> Strings;
984 
985   // Tersely prints the first N fields of a tuple to a string vector,
986   // one element for each field.
987 template <typename Tuple>
988 void TersePrintPrefixToStrings(const Tuple&, std::integral_constant<size_t, 0>,
989                                Strings*) {}
990 template <typename Tuple, size_t I>
991 void TersePrintPrefixToStrings(const Tuple& t,
992                                std::integral_constant<size_t, I>,
993                                Strings* strings) {
994   TersePrintPrefixToStrings(t, std::integral_constant<size_t, I - 1>(),
995                             strings);
996   ::std::stringstream ss;
997   UniversalTersePrint(std::get<I - 1>(t), &ss);
998   strings->push_back(ss.str());
999 }
1000 
1001 // Prints the fields of a tuple tersely to a string vector, one
1002 // element for each field.  See the comment before
1003 // UniversalTersePrint() for how we define "tersely".
1004 template <typename Tuple>
1005 Strings UniversalTersePrintTupleFieldsToStrings(const Tuple& value) {
1006   Strings result;
1007   TersePrintPrefixToStrings(
1008       value, std::integral_constant<size_t, std::tuple_size<Tuple>::value>(),
1009       &result);
1010   return result;
1011 }
1012 
1013 }  // namespace internal
1014 
1015 template <typename T>
1016 ::std::string PrintToString(const T& value) {
1017   ::std::stringstream ss;
1018   internal::UniversalTersePrinter<T>::Print(value, &ss);
1019   return ss.str();
1020 }
1021 
1022 }  // namespace testing
1023 
1024 // Include any custom printer added by the local installation.
1025 // We must include this header at the end to make sure it can use the
1026 // declarations from this file.
1027 #include "gtest/internal/custom/gtest-printers.h"
1028 
1029 #endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_PRINTERS_H_
1030