yaml-cpp

gtest-printers.h (34029B)

---

 // Copyright 2007, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
 // distribution.
 //     * Neither the name of Google Inc. nor the names of its
 // contributors may be used to endorse or promote products derived from
 // this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
 // Google Test - The Google C++ Testing and Mocking Framework
 //
 // This file implements a universal value printer that can print a
 // value of any type T:
 //
 //   void ::testing::internal::UniversalPrinter<T>::Print(value, ostream_ptr);
 //
 // A user can teach this function how to print a class type T by
 // defining either operator<<() or PrintTo() in the namespace that
 // defines T.  More specifically, the FIRST defined function in the
 // following list will be used (assuming T is defined in namespace
 // foo):
 //
 //   1. foo::PrintTo(const T&, ostream*)
 //   2. operator<<(ostream&, const T&) defined in either foo or the
 //      global namespace.
 //
 // However if T is an STL-style container then it is printed element-wise
 // unless foo::PrintTo(const T&, ostream*) is defined. Note that
 // operator<<() is ignored for container types.
 //
 // If none of the above is defined, it will print the debug string of
 // the value if it is a protocol buffer, or print the raw bytes in the
 // value otherwise.
 //
 // To aid debugging: when T is a reference type, the address of the
 // value is also printed; when T is a (const) char pointer, both the
 // pointer value and the NUL-terminated string it points to are
 // printed.
 //
 // We also provide some convenient wrappers:
 //
 //   // Prints a value to a string.  For a (const or not) char
 //   // pointer, the NUL-terminated string (but not the pointer) is
 //   // printed.
 //   std::string ::testing::PrintToString(const T& value);
 //
 //   // Prints a value tersely: for a reference type, the referenced
 //   // value (but not the address) is printed; for a (const or not) char
 //   // pointer, the NUL-terminated string (but not the pointer) is
 //   // printed.
 //   void ::testing::internal::UniversalTersePrint(const T& value, ostream*);
 //
 //   // Prints value using the type inferred by the compiler.  The difference
 //   // from UniversalTersePrint() is that this function prints both the
 //   // pointer and the NUL-terminated string for a (const or not) char pointer.
 //   void ::testing::internal::UniversalPrint(const T& value, ostream*);
 //
 //   // Prints the fields of a tuple tersely to a string vector, one
 //   // element for each field. Tuple support must be enabled in
 //   // gtest-port.h.
 //   std::vector<string> UniversalTersePrintTupleFieldsToStrings(
 //       const Tuple& value);
 //
 // Known limitation:
 //
 // The print primitives print the elements of an STL-style container
 // using the compiler-inferred type of *iter where iter is a
 // const_iterator of the container.  When const_iterator is an input
 // iterator but not a forward iterator, this inferred type may not
 // match value_type, and the print output may be incorrect.  In
 // practice, this is rarely a problem as for most containers
 // const_iterator is a forward iterator.  We'll fix this if there's an
 // actual need for it.  Note that this fix cannot rely on value_type
 // being defined as many user-defined container types don't have
 // value_type.
 
 // GOOGLETEST_CM0001 DO NOT DELETE
 
 #ifndef GTEST_INCLUDE_GTEST_GTEST_PRINTERS_H_
 #define GTEST_INCLUDE_GTEST_GTEST_PRINTERS_H_
 
 #include <functional>
 #include <ostream>  // NOLINT
 #include <sstream>
 #include <string>
 #include <tuple>
 #include <type_traits>
 #include <utility>
 #include <vector>
 #include "gtest/internal/gtest-internal.h"
 #include "gtest/internal/gtest-port.h"
 
 #if GTEST_HAS_ABSL
 #include "absl/strings/string_view.h"
 #include "absl/types/optional.h"
 #include "absl/types/variant.h"
 #endif  // GTEST_HAS_ABSL
 
 namespace testing {
 
 // Definitions in the 'internal' and 'internal2' name spaces are
 // subject to change without notice.  DO NOT USE THEM IN USER CODE!
 namespace internal2 {
 
 // Prints the given number of bytes in the given object to the given
 // ostream.
 GTEST_API_ void PrintBytesInObjectTo(const unsigned char* obj_bytes,
                                      size_t count,
                                      ::std::ostream* os);
 
 // For selecting which printer to use when a given type has neither <<
 // nor PrintTo().
 enum TypeKind {
   kProtobuf,              // a protobuf type
   kConvertibleToInteger,  // a type implicitly convertible to BiggestInt
                           // (e.g. a named or unnamed enum type)
 #if GTEST_HAS_ABSL
   kConvertibleToStringView,  // a type implicitly convertible to
                              // absl::string_view
 #endif
   kOtherType  // anything else
 };
 
 // TypeWithoutFormatter<T, kTypeKind>::PrintValue(value, os) is called
 // by the universal printer to print a value of type T when neither
 // operator<< nor PrintTo() is defined for T, where kTypeKind is the
 // "kind" of T as defined by enum TypeKind.
 template <typename T, TypeKind kTypeKind>
 class TypeWithoutFormatter {
  public:
   // This default version is called when kTypeKind is kOtherType.
   static void PrintValue(const T& value, ::std::ostream* os) {
     PrintBytesInObjectTo(
         static_cast<const unsigned char*>(
             reinterpret_cast<const void*>(std::addressof(value))),
         sizeof(value), os);
   }
 };
 
 // We print a protobuf using its ShortDebugString() when the string
 // doesn't exceed this many characters; otherwise we print it using
 // DebugString() for better readability.
 const size_t kProtobufOneLinerMaxLength = 50;
 
 template <typename T>
 class TypeWithoutFormatter<T, kProtobuf> {
  public:
   static void PrintValue(const T& value, ::std::ostream* os) {
     std::string pretty_str = value.ShortDebugString();
     if (pretty_str.length() > kProtobufOneLinerMaxLength) {
       pretty_str = "\n" + value.DebugString();
     }
     *os << ("<" + pretty_str + ">");
   }
 };
 
 template <typename T>
 class TypeWithoutFormatter<T, kConvertibleToInteger> {
  public:
   // Since T has no << operator or PrintTo() but can be implicitly
   // converted to BiggestInt, we print it as a BiggestInt.
   //
   // Most likely T is an enum type (either named or unnamed), in which
   // case printing it as an integer is the desired behavior.  In case
   // T is not an enum, printing it as an integer is the best we can do
   // given that it has no user-defined printer.
   static void PrintValue(const T& value, ::std::ostream* os) {
     const internal::BiggestInt kBigInt = value;
     *os << kBigInt;
   }
 };
 
 #if GTEST_HAS_ABSL
 template <typename T>
 class TypeWithoutFormatter<T, kConvertibleToStringView> {
  public:
   // Since T has neither operator<< nor PrintTo() but can be implicitly
   // converted to absl::string_view, we print it as a absl::string_view.
   //
   // Note: the implementation is further below, as it depends on
   // internal::PrintTo symbol which is defined later in the file.
   static void PrintValue(const T& value, ::std::ostream* os);
 };
 #endif
 
 // Prints the given value to the given ostream.  If the value is a
 // protocol message, its debug string is printed; if it's an enum or
 // of a type implicitly convertible to BiggestInt, it's printed as an
 // integer; otherwise the bytes in the value are printed.  This is
 // what UniversalPrinter<T>::Print() does when it knows nothing about
 // type T and T has neither << operator nor PrintTo().
 //
 // A user can override this behavior for a class type Foo by defining
 // a << operator in the namespace where Foo is defined.
 //
 // We put this operator in namespace 'internal2' instead of 'internal'
 // to simplify the implementation, as much code in 'internal' needs to
 // use << in STL, which would conflict with our own << were it defined
 // in 'internal'.
 //
 // Note that this operator<< takes a generic std::basic_ostream<Char,
 // CharTraits> type instead of the more restricted std::ostream.  If
 // we define it to take an std::ostream instead, we'll get an
 // "ambiguous overloads" compiler error when trying to print a type
 // Foo that supports streaming to std::basic_ostream<Char,
 // CharTraits>, as the compiler cannot tell whether
 // operator<<(std::ostream&, const T&) or
 // operator<<(std::basic_stream<Char, CharTraits>, const Foo&) is more
 // specific.
 template <typename Char, typename CharTraits, typename T>
 ::std::basic_ostream<Char, CharTraits>& operator<<(
     ::std::basic_ostream<Char, CharTraits>& os, const T& x) {
   TypeWithoutFormatter<T, (internal::IsAProtocolMessage<T>::value
                                ? kProtobuf
                                : std::is_convertible<
                                      const T&, internal::BiggestInt>::value
                                      ? kConvertibleToInteger
                                      :
 #if GTEST_HAS_ABSL
                                      std::is_convertible<
                                          const T&, absl::string_view>::value
                                          ? kConvertibleToStringView
                                          :
 #endif
                                          kOtherType)>::PrintValue(x, &os);
   return os;
 }
 
 }  // namespace internal2
 }  // namespace testing
 
 // This namespace MUST NOT BE NESTED IN ::testing, or the name look-up
 // magic needed for implementing UniversalPrinter won't work.
 namespace testing_internal {
 
 // Used to print a value that is not an STL-style container when the
 // user doesn't define PrintTo() for it.
 template <typename T>
 void DefaultPrintNonContainerTo(const T& value, ::std::ostream* os) {
   // With the following statement, during unqualified name lookup,
   // testing::internal2::operator<< appears as if it was declared in
   // the nearest enclosing namespace that contains both
   // ::testing_internal and ::testing::internal2, i.e. the global
   // namespace.  For more details, refer to the C++ Standard section
   // 7.3.4-1 [namespace.udir].  This allows us to fall back onto
   // testing::internal2::operator<< in case T doesn't come with a <<
   // operator.
   //
   // We cannot write 'using ::testing::internal2::operator<<;', which
   // gcc 3.3 fails to compile due to a compiler bug.
   using namespace ::testing::internal2;  // NOLINT
 
   // Assuming T is defined in namespace foo, in the next statement,
   // the compiler will consider all of:
   //
   //   1. foo::operator<< (thanks to Koenig look-up),
   //   2. ::operator<< (as the current namespace is enclosed in ::),
   //   3. testing::internal2::operator<< (thanks to the using statement above).
   //
   // The operator<< whose type matches T best will be picked.
   //
   // We deliberately allow #2 to be a candidate, as sometimes it's
   // impossible to define #1 (e.g. when foo is ::std, defining
   // anything in it is undefined behavior unless you are a compiler
   // vendor.).
   *os << value;
 }
 
 }  // namespace testing_internal
 
 namespace testing {
 namespace internal {
 
 // FormatForComparison<ToPrint, OtherOperand>::Format(value) formats a
 // value of type ToPrint that is an operand of a comparison assertion
 // (e.g. ASSERT_EQ).  OtherOperand is the type of the other operand in
 // the comparison, and is used to help determine the best way to
 // format the value.  In particular, when the value is a C string
 // (char pointer) and the other operand is an STL string object, we
 // want to format the C string as a string, since we know it is
 // compared by value with the string object.  If the value is a char
 // pointer but the other operand is not an STL string object, we don't
 // know whether the pointer is supposed to point to a NUL-terminated
 // string, and thus want to print it as a pointer to be safe.
 //
 // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
 
 // The default case.
 template <typename ToPrint, typename OtherOperand>
 class FormatForComparison {
  public:
   static ::std::string Format(const ToPrint& value) {
     return ::testing::PrintToString(value);
   }
 };
 
 // Array.
 template <typename ToPrint, size_t N, typename OtherOperand>
 class FormatForComparison<ToPrint[N], OtherOperand> {
  public:
   static ::std::string Format(const ToPrint* value) {
     return FormatForComparison<const ToPrint*, OtherOperand>::Format(value);
   }
 };
 
 // By default, print C string as pointers to be safe, as we don't know
 // whether they actually point to a NUL-terminated string.
 
 #define GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(CharType)                \
   template <typename OtherOperand>                                      \
   class FormatForComparison<CharType*, OtherOperand> {                  \
    public:                                                              \
     static ::std::string Format(CharType* value) {                      \
       return ::testing::PrintToString(static_cast<const void*>(value)); \
     }                                                                   \
   }
 
 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(char);
 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const char);
 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(wchar_t);
 GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const wchar_t);
 
 #undef GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_
 
 // If a C string is compared with an STL string object, we know it's meant
 // to point to a NUL-terminated string, and thus can print it as a string.
 
 #define GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(CharType, OtherStringType) \
   template <>                                                           \
   class FormatForComparison<CharType*, OtherStringType> {               \
    public:                                                              \
     static ::std::string Format(CharType* value) {                      \
       return ::testing::PrintToString(value);                           \
     }                                                                   \
   }
 
 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char, ::std::string);
 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char, ::std::string);
 
 #if GTEST_HAS_STD_WSTRING
 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(wchar_t, ::std::wstring);
 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const wchar_t, ::std::wstring);
 #endif
 
 #undef GTEST_IMPL_FORMAT_C_STRING_AS_STRING_
 
 // Formats a comparison assertion (e.g. ASSERT_EQ, EXPECT_LT, and etc)
 // operand to be used in a failure message.  The type (but not value)
 // of the other operand may affect the format.  This allows us to
 // print a char* as a raw pointer when it is compared against another
 // char* or void*, and print it as a C string when it is compared
 // against an std::string object, for example.
 //
 // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
 template <typename T1, typename T2>
 std::string FormatForComparisonFailureMessage(
     const T1& value, const T2& /* other_operand */) {
   return FormatForComparison<T1, T2>::Format(value);
 }
 
 // UniversalPrinter<T>::Print(value, ostream_ptr) prints the given
 // value to the given ostream.  The caller must ensure that
 // 'ostream_ptr' is not NULL, or the behavior is undefined.
 //
 // We define UniversalPrinter as a class template (as opposed to a
 // function template), as we need to partially specialize it for
 // reference types, which cannot be done with function templates.
 template <typename T>
 class UniversalPrinter;
 
 template <typename T>
 void UniversalPrint(const T& value, ::std::ostream* os);
 
 enum DefaultPrinterType {
   kPrintContainer,
   kPrintPointer,
   kPrintFunctionPointer,
   kPrintOther,
 };
 template <DefaultPrinterType type> struct WrapPrinterType {};
 
 // Used to print an STL-style container when the user doesn't define
 // a PrintTo() for it.
 template <typename C>
 void DefaultPrintTo(WrapPrinterType<kPrintContainer> /* dummy */,
                     const C& container, ::std::ostream* os) {
   const size_t kMaxCount = 32;  // The maximum number of elements to print.
   *os << '{';
   size_t count = 0;
   for (typename C::const_iterator it = container.begin();
        it != container.end(); ++it, ++count) {
     if (count > 0) {
       *os << ',';
       if (count == kMaxCount) {  // Enough has been printed.
         *os << " ...";
         break;
       }
     }
     *os << ' ';
     // We cannot call PrintTo(*it, os) here as PrintTo() doesn't
     // handle *it being a native array.
     internal::UniversalPrint(*it, os);
   }
 
   if (count > 0) {
     *os << ' ';
   }
   *os << '}';
 }
 
 // Used to print a pointer that is neither a char pointer nor a member
 // pointer, when the user doesn't define PrintTo() for it.  (A member
 // variable pointer or member function pointer doesn't really point to
 // a location in the address space.  Their representation is
 // implementation-defined.  Therefore they will be printed as raw
 // bytes.)
 template <typename T>
 void DefaultPrintTo(WrapPrinterType<kPrintPointer> /* dummy */,
                     T* p, ::std::ostream* os) {
   if (p == nullptr) {
     *os << "NULL";
   } else {
     // T is not a function type.  We just call << to print p,
     // relying on ADL to pick up user-defined << for their pointer
     // types, if any.
     *os << p;
   }
 }
 template <typename T>
 void DefaultPrintTo(WrapPrinterType<kPrintFunctionPointer> /* dummy */,
                     T* p, ::std::ostream* os) {
   if (p == nullptr) {
     *os << "NULL";
   } else {
     // T is a function type, so '*os << p' doesn't do what we want
     // (it just prints p as bool).  We want to print p as a const
     // void*.
     *os << reinterpret_cast<const void*>(p);
   }
 }
 
 // Used to print a non-container, non-pointer value when the user
 // doesn't define PrintTo() for it.
 template <typename T>
 void DefaultPrintTo(WrapPrinterType<kPrintOther> /* dummy */,
                     const T& value, ::std::ostream* os) {
   ::testing_internal::DefaultPrintNonContainerTo(value, os);
 }
 
 // Prints the given value using the << operator if it has one;
 // otherwise prints the bytes in it.  This is what
 // UniversalPrinter<T>::Print() does when PrintTo() is not specialized
 // or overloaded for type T.
 //
 // A user can override this behavior for a class type Foo by defining
 // an overload of PrintTo() in the namespace where Foo is defined.  We
 // give the user this option as sometimes defining a << operator for
 // Foo is not desirable (e.g. the coding style may prevent doing it,
 // or there is already a << operator but it doesn't do what the user
 // wants).
 template <typename T>
 void PrintTo(const T& value, ::std::ostream* os) {
   // DefaultPrintTo() is overloaded.  The type of its first argument
   // determines which version will be picked.
   //
   // Note that we check for container types here, prior to we check
   // for protocol message types in our operator<<.  The rationale is:
   //
   // For protocol messages, we want to give people a chance to
   // override Google Mock's format by defining a PrintTo() or
   // operator<<.  For STL containers, other formats can be
   // incompatible with Google Mock's format for the container
   // elements; therefore we check for container types here to ensure
   // that our format is used.
   //
   // Note that MSVC and clang-cl do allow an implicit conversion from
   // pointer-to-function to pointer-to-object, but clang-cl warns on it.
   // So don't use ImplicitlyConvertible if it can be helped since it will
   // cause this warning, and use a separate overload of DefaultPrintTo for
   // function pointers so that the `*os << p` in the object pointer overload
   // doesn't cause that warning either.
   DefaultPrintTo(
       WrapPrinterType <
                   (sizeof(IsContainerTest<T>(0)) == sizeof(IsContainer)) &&
               !IsRecursiveContainer<T>::value
           ? kPrintContainer
           : !std::is_pointer<T>::value
                 ? kPrintOther
                 : std::is_function<typename std::remove_pointer<T>::type>::value
                       ? kPrintFunctionPointer
                       : kPrintPointer > (),
       value, os);
 }
 
 // The following list of PrintTo() overloads tells
 // UniversalPrinter<T>::Print() how to print standard types (built-in
 // types, strings, plain arrays, and pointers).
 
 // Overloads for various char types.
 GTEST_API_ void PrintTo(unsigned char c, ::std::ostream* os);
 GTEST_API_ void PrintTo(signed char c, ::std::ostream* os);
 inline void PrintTo(char c, ::std::ostream* os) {
   // When printing a plain char, we always treat it as unsigned.  This
   // way, the output won't be affected by whether the compiler thinks
   // char is signed or not.
   PrintTo(static_cast<unsigned char>(c), os);
 }
 
 // Overloads for other simple built-in types.
 inline void PrintTo(bool x, ::std::ostream* os) {
   *os << (x ? "true" : "false");
 }
 
 // Overload for wchar_t type.
 // Prints a wchar_t as a symbol if it is printable or as its internal
 // code otherwise and also as its decimal code (except for L'\0').
 // The L'\0' char is printed as "L'\\0'". The decimal code is printed
 // as signed integer when wchar_t is implemented by the compiler
 // as a signed type and is printed as an unsigned integer when wchar_t
 // is implemented as an unsigned type.
 GTEST_API_ void PrintTo(wchar_t wc, ::std::ostream* os);
 
 // Overloads for C strings.
 GTEST_API_ void PrintTo(const char* s, ::std::ostream* os);
 inline void PrintTo(char* s, ::std::ostream* os) {
   PrintTo(ImplicitCast_<const char*>(s), os);
 }
 
 // signed/unsigned char is often used for representing binary data, so
 // we print pointers to it as void* to be safe.
 inline void PrintTo(const signed char* s, ::std::ostream* os) {
   PrintTo(ImplicitCast_<const void*>(s), os);
 }
 inline void PrintTo(signed char* s, ::std::ostream* os) {
   PrintTo(ImplicitCast_<const void*>(s), os);
 }
 inline void PrintTo(const unsigned char* s, ::std::ostream* os) {
   PrintTo(ImplicitCast_<const void*>(s), os);
 }
 inline void PrintTo(unsigned char* s, ::std::ostream* os) {
   PrintTo(ImplicitCast_<const void*>(s), os);
 }
 
 // MSVC can be configured to define wchar_t as a typedef of unsigned
 // short.  It defines _NATIVE_WCHAR_T_DEFINED when wchar_t is a native
 // type.  When wchar_t is a typedef, defining an overload for const
 // wchar_t* would cause unsigned short* be printed as a wide string,
 // possibly causing invalid memory accesses.
 #if !defined(_MSC_VER) || defined(_NATIVE_WCHAR_T_DEFINED)
 // Overloads for wide C strings
 GTEST_API_ void PrintTo(const wchar_t* s, ::std::ostream* os);
 inline void PrintTo(wchar_t* s, ::std::ostream* os) {
   PrintTo(ImplicitCast_<const wchar_t*>(s), os);
 }
 #endif
 
 // Overload for C arrays.  Multi-dimensional arrays are printed
 // properly.
 
 // Prints the given number of elements in an array, without printing
 // the curly braces.
 template <typename T>
 void PrintRawArrayTo(const T a[], size_t count, ::std::ostream* os) {
   UniversalPrint(a[0], os);
   for (size_t i = 1; i != count; i++) {
     *os << ", ";
     UniversalPrint(a[i], os);
   }
 }
 
 // Overloads for ::std::string.
 GTEST_API_ void PrintStringTo(const ::std::string&s, ::std::ostream* os);
 inline void PrintTo(const ::std::string& s, ::std::ostream* os) {
   PrintStringTo(s, os);
 }
 
 // Overloads for ::std::wstring.
 #if GTEST_HAS_STD_WSTRING
 GTEST_API_ void PrintWideStringTo(const ::std::wstring&s, ::std::ostream* os);
 inline void PrintTo(const ::std::wstring& s, ::std::ostream* os) {
   PrintWideStringTo(s, os);
 }
 #endif  // GTEST_HAS_STD_WSTRING
 
 #if GTEST_HAS_ABSL
 // Overload for absl::string_view.
 inline void PrintTo(absl::string_view sp, ::std::ostream* os) {
   PrintTo(::std::string(sp), os);
 }
 #endif  // GTEST_HAS_ABSL
 
 inline void PrintTo(std::nullptr_t, ::std::ostream* os) { *os << "(nullptr)"; }
 
 template <typename T>
 void PrintTo(std::reference_wrapper<T> ref, ::std::ostream* os) {
   UniversalPrinter<T&>::Print(ref.get(), os);
 }
 
 // Helper function for printing a tuple.  T must be instantiated with
 // a tuple type.
 template <typename T>
 void PrintTupleTo(const T&, std::integral_constant<size_t, 0>,
                   ::std::ostream*) {}
 
 template <typename T, size_t I>
 void PrintTupleTo(const T& t, std::integral_constant<size_t, I>,
                   ::std::ostream* os) {
   PrintTupleTo(t, std::integral_constant<size_t, I - 1>(), os);
   GTEST_INTENTIONAL_CONST_COND_PUSH_()
   if (I > 1) {
     GTEST_INTENTIONAL_CONST_COND_POP_()
     *os << ", ";
   }
   UniversalPrinter<typename std::tuple_element<I - 1, T>::type>::Print(
       std::get<I - 1>(t), os);
 }
 
 template <typename... Types>
 void PrintTo(const ::std::tuple<Types...>& t, ::std::ostream* os) {
   *os << "(";
   PrintTupleTo(t, std::integral_constant<size_t, sizeof...(Types)>(), os);
   *os << ")";
 }
 
 // Overload for std::pair.
 template <typename T1, typename T2>
 void PrintTo(const ::std::pair<T1, T2>& value, ::std::ostream* os) {
   *os << '(';
   // We cannot use UniversalPrint(value.first, os) here, as T1 may be
   // a reference type.  The same for printing value.second.
   UniversalPrinter<T1>::Print(value.first, os);
   *os << ", ";
   UniversalPrinter<T2>::Print(value.second, os);
   *os << ')';
 }
 
 // Implements printing a non-reference type T by letting the compiler
 // pick the right overload of PrintTo() for T.
 template <typename T>
 class UniversalPrinter {
  public:
   // MSVC warns about adding const to a function type, so we want to
   // disable the warning.
   GTEST_DISABLE_MSC_WARNINGS_PUSH_(4180)
 
   // Note: we deliberately don't call this PrintTo(), as that name
   // conflicts with ::testing::internal::PrintTo in the body of the
   // function.
   static void Print(const T& value, ::std::ostream* os) {
     // By default, ::testing::internal::PrintTo() is used for printing
     // the value.
     //
     // Thanks to Koenig look-up, if T is a class and has its own
     // PrintTo() function defined in its namespace, that function will
     // be visible here.  Since it is more specific than the generic ones
     // in ::testing::internal, it will be picked by the compiler in the
     // following statement - exactly what we want.
     PrintTo(value, os);
   }
 
   GTEST_DISABLE_MSC_WARNINGS_POP_()
 };
 
 #if GTEST_HAS_ABSL
 
 // Printer for absl::optional
 
 template <typename T>
 class UniversalPrinter<::absl::optional<T>> {
  public:
   static void Print(const ::absl::optional<T>& value, ::std::ostream* os) {
     *os << '(';
     if (!value) {
       *os << "nullopt";
     } else {
       UniversalPrint(*value, os);
     }
     *os << ')';
   }
 };
 
 // Printer for absl::variant
 
 template <typename... T>
 class UniversalPrinter<::absl::variant<T...>> {
  public:
   static void Print(const ::absl::variant<T...>& value, ::std::ostream* os) {
     *os << '(';
     absl::visit(Visitor{os}, value);
     *os << ')';
   }
 
  private:
   struct Visitor {
     template <typename U>
     void operator()(const U& u) const {
       *os << "'" << GetTypeName<U>() << "' with value ";
       UniversalPrint(u, os);
     }
     ::std::ostream* os;
   };
 };
 
 #endif  // GTEST_HAS_ABSL
 
 // UniversalPrintArray(begin, len, os) prints an array of 'len'
 // elements, starting at address 'begin'.
 template <typename T>
 void UniversalPrintArray(const T* begin, size_t len, ::std::ostream* os) {
   if (len == 0) {
     *os << "{}";
   } else {
     *os << "{ ";
     const size_t kThreshold = 18;
     const size_t kChunkSize = 8;
     // If the array has more than kThreshold elements, we'll have to
     // omit some details by printing only the first and the last
     // kChunkSize elements.
     if (len <= kThreshold) {
       PrintRawArrayTo(begin, len, os);
     } else {
       PrintRawArrayTo(begin, kChunkSize, os);
       *os << ", ..., ";
       PrintRawArrayTo(begin + len - kChunkSize, kChunkSize, os);
     }
     *os << " }";
   }
 }
 // This overload prints a (const) char array compactly.
 GTEST_API_ void UniversalPrintArray(
     const char* begin, size_t len, ::std::ostream* os);
 
 // This overload prints a (const) wchar_t array compactly.
 GTEST_API_ void UniversalPrintArray(
     const wchar_t* begin, size_t len, ::std::ostream* os);
 
 // Implements printing an array type T[N].
 template <typename T, size_t N>
 class UniversalPrinter<T[N]> {
  public:
   // Prints the given array, omitting some elements when there are too
   // many.
   static void Print(const T (&a)[N], ::std::ostream* os) {
     UniversalPrintArray(a, N, os);
   }
 };
 
 // Implements printing a reference type T&.
 template <typename T>
 class UniversalPrinter<T&> {
  public:
   // MSVC warns about adding const to a function type, so we want to
   // disable the warning.
   GTEST_DISABLE_MSC_WARNINGS_PUSH_(4180)
 
   static void Print(const T& value, ::std::ostream* os) {
     // Prints the address of the value.  We use reinterpret_cast here
     // as static_cast doesn't compile when T is a function type.
     *os << "@" << reinterpret_cast<const void*>(&value) << " ";
 
     // Then prints the value itself.
     UniversalPrint(value, os);
   }
 
   GTEST_DISABLE_MSC_WARNINGS_POP_()
 };
 
 // Prints a value tersely: for a reference type, the referenced value
 // (but not the address) is printed; for a (const) char pointer, the
 // NUL-terminated string (but not the pointer) is printed.
 
 template <typename T>
 class UniversalTersePrinter {
  public:
   static void Print(const T& value, ::std::ostream* os) {
     UniversalPrint(value, os);
   }
 };
 template <typename T>
 class UniversalTersePrinter<T&> {
  public:
   static void Print(const T& value, ::std::ostream* os) {
     UniversalPrint(value, os);
   }
 };
 template <typename T, size_t N>
 class UniversalTersePrinter<T[N]> {
  public:
   static void Print(const T (&value)[N], ::std::ostream* os) {
     UniversalPrinter<T[N]>::Print(value, os);
   }
 };
 template <>
 class UniversalTersePrinter<const char*> {
  public:
   static void Print(const char* str, ::std::ostream* os) {
     if (str == nullptr) {
       *os << "NULL";
     } else {
       UniversalPrint(std::string(str), os);
     }
   }
 };
 template <>
 class UniversalTersePrinter<char*> {
  public:
   static void Print(char* str, ::std::ostream* os) {
     UniversalTersePrinter<const char*>::Print(str, os);
   }
 };
 
 #if GTEST_HAS_STD_WSTRING
 template <>
 class UniversalTersePrinter<const wchar_t*> {
  public:
   static void Print(const wchar_t* str, ::std::ostream* os) {
     if (str == nullptr) {
       *os << "NULL";
     } else {
       UniversalPrint(::std::wstring(str), os);
     }
   }
 };
 #endif
 
 template <>
 class UniversalTersePrinter<wchar_t*> {
  public:
   static void Print(wchar_t* str, ::std::ostream* os) {
     UniversalTersePrinter<const wchar_t*>::Print(str, os);
   }
 };
 
 template <typename T>
 void UniversalTersePrint(const T& value, ::std::ostream* os) {
   UniversalTersePrinter<T>::Print(value, os);
 }
 
 // Prints a value using the type inferred by the compiler.  The
 // difference between this and UniversalTersePrint() is that for a
 // (const) char pointer, this prints both the pointer and the
 // NUL-terminated string.
 template <typename T>
 void UniversalPrint(const T& value, ::std::ostream* os) {
   // A workarond for the bug in VC++ 7.1 that prevents us from instantiating
   // UniversalPrinter with T directly.
   typedef T T1;
   UniversalPrinter<T1>::Print(value, os);
 }
 
 typedef ::std::vector< ::std::string> Strings;
 
   // Tersely prints the first N fields of a tuple to a string vector,
   // one element for each field.
 template <typename Tuple>
 void TersePrintPrefixToStrings(const Tuple&, std::integral_constant<size_t, 0>,
                                Strings*) {}
 template <typename Tuple, size_t I>
 void TersePrintPrefixToStrings(const Tuple& t,
                                std::integral_constant<size_t, I>,
                                Strings* strings) {
   TersePrintPrefixToStrings(t, std::integral_constant<size_t, I - 1>(),
                             strings);
   ::std::stringstream ss;
   UniversalTersePrint(std::get<I - 1>(t), &ss);
   strings->push_back(ss.str());
 }
 
 // Prints the fields of a tuple tersely to a string vector, one
 // element for each field.  See the comment before
 // UniversalTersePrint() for how we define "tersely".
 template <typename Tuple>
 Strings UniversalTersePrintTupleFieldsToStrings(const Tuple& value) {
   Strings result;
   TersePrintPrefixToStrings(
       value, std::integral_constant<size_t, std::tuple_size<Tuple>::value>(),
       &result);
   return result;
 }
 
 }  // namespace internal
 
 #if GTEST_HAS_ABSL
 namespace internal2 {
 template <typename T>
 void TypeWithoutFormatter<T, kConvertibleToStringView>::PrintValue(
     const T& value, ::std::ostream* os) {
   internal::PrintTo(absl::string_view(value), os);
 }
 }  // namespace internal2
 #endif
 
 template <typename T>
 ::std::string PrintToString(const T& value) {
   ::std::stringstream ss;
   internal::UniversalTersePrinter<T>::Print(value, &ss);
   return ss.str();
 }
 
 }  // namespace testing
 
 // Include any custom printer added by the local installation.
 // We must include this header at the end to make sure it can use the
 // declarations from this file.
 #include "gtest/internal/custom/gtest-printers.h"
 
 #endif  // GTEST_INCLUDE_GTEST_GTEST_PRINTERS_H_