From 0bf8ea3065f791289f383afee43d8464638a5075 Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Tue, 3 Mar 2020 12:17:35 -0500 Subject: Googletest export Simplify the fallback printing logic to have a single sequence of trial printers. PiperOrigin-RevId: 298621376 --- googletest/include/gtest/gtest-printers.h | 413 ++++++++++++------------------ googletest/src/gtest-printers.cc | 6 +- 2 files changed, 160 insertions(+), 259 deletions(-) diff --git a/googletest/include/gtest/gtest-printers.h b/googletest/include/gtest/gtest-printers.h index 407d1f1..75e4422 100644 --- a/googletest/include/gtest/gtest-printers.h +++ b/googletest/include/gtest/gtest-printers.h @@ -119,53 +119,126 @@ 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 { +// Definitions in the internal* namespaces are subject to change without notice. +// DO NOT USE THEM IN USER CODE! +namespace internal { -// 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); +template +void UniversalPrint(const T& value, ::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_INTERNAL_HAS_STRING_VIEW - kConvertibleToStringView, // a type implicitly convertible to - // absl::string_view or std::string_view -#endif - kOtherType // anything else +// Used to print an STL-style container when the user doesn't define +// a PrintTo() for it. +struct ContainerPrinter { + template (0)) == sizeof(IsContainer)) && + !IsRecursiveContainer::value>::type> + static void PrintValue(const T& container, std::ostream* os) { + const size_t kMaxCount = 32; // The maximum number of elements to print. + *os << '{'; + size_t count = 0; + for (auto&& elem : container) { + if (count > 0) { + *os << ','; + if (count == kMaxCount) { // Enough has been printed. + *os << " ..."; + break; + } + } + *os << ' '; + // We cannot call PrintTo(elem, os) here as PrintTo() doesn't + // handle `elem` being a native array. + internal::UniversalPrint(elem, os); + ++count; + } + + if (count > 0) { + *os << ' '; + } + *os << '}'; + } }; -// TypeWithoutFormatter::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 -class TypeWithoutFormatter { - public: - // This default version is called when kTypeKind is kOtherType. - static void PrintValue(const T& value, ::std::ostream* os) { - PrintBytesInObjectTo( - static_cast( - reinterpret_cast(std::addressof(value))), - sizeof(value), 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.) +struct FunctionPointerPrinter { + template ::value>::type> + static void PrintValue(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(p); + } } }; -// 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; +struct PointerPrinter { + template + static void PrintValue(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; + } + } +}; +namespace internal_stream { + +struct Sentinel; +template +Sentinel* operator<<(::std::basic_ostream& os, const T& x); + +// Check if the user has a user-defined operator<< for their type. +// +// We put this in its own namespace to inject a custom operator<< that allows us +// to probe the type's operator. +// +// Note that this operator<< takes a generic std::basic_ostream 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, as the compiler cannot tell whether +// operator<<(std::ostream&, const T&) or +// operator<<(std::basic_stream, const Foo&) is more +// specific. template -class TypeWithoutFormatter { - public: +constexpr bool UseStreamOperator() { + return !std::is_same() + << std::declval()), + Sentinel*>::value; +} + +} // namespace internal_stream + +struct StreamPrinter { + template ()>::type> + static void PrintValue(const T& value, ::std::ostream* os) { + *os << value; + } +}; + +struct ProtobufPrinter { + // 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. + static const size_t kProtobufOneLinerMaxLength = 50; + + template ::value>::type> static void PrintValue(const T& value, ::std::ostream* os) { std::string pretty_str = value.ShortDebugString(); if (pretty_str.length() > kProtobufOneLinerMaxLength) { @@ -175,9 +248,7 @@ class TypeWithoutFormatter { } }; -template -class TypeWithoutFormatter { - public: +struct ConvertibleToIntegerPrinter { // Since T has no << operator or PrintTo() but can be implicitly // converted to BiggestInt, we print it as a BiggestInt. // @@ -185,112 +256,64 @@ class TypeWithoutFormatter { // 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; + static void PrintValue(internal::BiggestInt value, ::std::ostream* os) { + *os << value; } }; +struct ConvertibleToStringViewPrinter { #if GTEST_INTERNAL_HAS_STRING_VIEW -template -class TypeWithoutFormatter { - 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 - // (or std::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); -}; + static void PrintValue(internal::StringView value, ::std::ostream* os) { + internal::UniversalPrint(value, 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::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 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, as the compiler cannot tell whether -// operator<<(std::ostream&, const T&) or -// operator<<(std::basic_stream, const Foo&) is more -// specific. -template -::std::basic_ostream& operator<<( - ::std::basic_ostream& os, const T& x) { - TypeWithoutFormatter::value - ? kProtobuf - : std::is_convertible< - const T&, internal::BiggestInt>::value - ? kConvertibleToInteger - : -#if GTEST_INTERNAL_HAS_STRING_VIEW - std::is_convertible< - const T&, internal::StringView>::value - ? kConvertibleToStringView - : -#endif - kOtherType)>::PrintValue(x, &os); - return os; -} -} // namespace internal2 -} // namespace testing +// 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); +struct FallbackPrinter { + template + static void PrintValue(const T& value, ::std::ostream* os) { + PrintBytesInObjectTo( + static_cast( + reinterpret_cast(std::addressof(value))), + sizeof(value), os); + } +}; + +// Try every printer in order and return the first one that works. +template +struct FindFirstPrinter : FindFirstPrinter {}; -// This namespace MUST NOT BE NESTED IN ::testing, or the name look-up -// magic needed for implementing UniversalPrinter won't work. -namespace testing_internal { +template +struct FindFirstPrinter< + T, decltype(Printer::PrintValue(std::declval(), nullptr)), + Printer, Printers...> { + using type = Printer; +}; -// Used to print a value that is not an STL-style container when the -// user doesn't define PrintTo() for it. +// Select the best printer in the following order: +// - Print containers (they have begin/end/etc). +// - Print function pointers. +// - Print object pointers. +// - Use the stream operator, if available. +// - Print protocol buffers. +// - Print types convertible to BiggestInt. +// - Print types convertible to StringView, if available. +// - Fallback to printing the raw bytes of the object. template -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. - - using ::testing::internal2::operator<<; - - // 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; +void PrintWithFallback(const T& value, ::std::ostream* os) { + using Printer = typename FindFirstPrinter< + T, void, ContainerPrinter, FunctionPointerPrinter, PointerPrinter, + StreamPrinter, ProtobufPrinter, ConvertibleToIntegerPrinter, + ConvertibleToStringViewPrinter, FallbackPrinter>::type; + Printer::PrintValue(value, os); } -} // namespace testing_internal - -namespace testing { -namespace internal { - // FormatForComparison::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 @@ -388,85 +411,6 @@ std::string FormatForComparisonFailureMessage( template class UniversalPrinter; -template -void UniversalPrint(const T& value, ::std::ostream* os); - -enum DefaultPrinterType { - kPrintContainer, - kPrintPointer, - kPrintFunctionPointer, - kPrintOther, -}; -template struct WrapPrinterType {}; - -// Used to print an STL-style container when the user doesn't define -// a PrintTo() for it. -template -void DefaultPrintTo(WrapPrinterType /* 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 -void DefaultPrintTo(WrapPrinterType /* 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 -void DefaultPrintTo(WrapPrinterType /* 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(p); - } -} - -// Used to print a non-container, non-pointer value when the user -// doesn't define PrintTo() for it. -template -void DefaultPrintTo(WrapPrinterType /* 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::Print() does when PrintTo() is not specialized @@ -480,36 +424,7 @@ void DefaultPrintTo(WrapPrinterType /* dummy */, // wants). template 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(0)) == sizeof(IsContainer)) && - !IsRecursiveContainer::value - ? kPrintContainer - : !std::is_pointer::value - ? kPrintOther - : std::is_function::type>::value - ? kPrintFunctionPointer - : kPrintPointer > (), - value, os); + internal::PrintWithFallback(value, os); } // The following list of PrintTo() overloads tells @@ -900,16 +815,6 @@ Strings UniversalTersePrintTupleFieldsToStrings(const Tuple& value) { } // namespace internal -#if GTEST_INTERNAL_HAS_STRING_VIEW -namespace internal2 { -template -void TypeWithoutFormatter::PrintValue( - const T& value, ::std::ostream* os) { - internal::PrintTo(internal::StringView(value), os); -} -} // namespace internal2 -#endif - template ::std::string PrintToString(const T& value) { ::std::stringstream ss; diff --git a/googletest/src/gtest-printers.cc b/googletest/src/gtest-printers.cc index 3337be3..4e1ccad 100644 --- a/googletest/src/gtest-printers.cc +++ b/googletest/src/gtest-printers.cc @@ -104,7 +104,7 @@ void PrintBytesInObjectToImpl(const unsigned char* obj_bytes, size_t count, } // namespace -namespace internal2 { +namespace internal { // Delegates to PrintBytesInObjectToImpl() to print the bytes in the // given object. The delegation simplifies the implementation, which @@ -116,10 +116,6 @@ void PrintBytesInObjectTo(const unsigned char* obj_bytes, size_t count, PrintBytesInObjectToImpl(obj_bytes, count, os); } -} // namespace internal2 - -namespace internal { - // Depending on the value of a char (or wchar_t), we print it in one // of three formats: // - as is if it's a printable ASCII (e.g. 'a', '2', ' '), -- cgit v0.12