From 7d3b73c85a42811309eac26e5cbe054c40b64785 Mon Sep 17 00:00:00 2001
From: Abseil Team <absl-team@google.com>
Date: Tue, 9 Oct 2018 14:50:26 -0400
Subject: Unconditionally use std::tuple. Remove all mention of TR1 tuple and
 our own implementation of tuple.

PiperOrigin-RevId: 216395043
---
 googletest/include/gtest/gtest-printers.h | 223 +++++-------------------------
 1 file changed, 34 insertions(+), 189 deletions(-)

(limited to 'googletest/include/gtest/gtest-printers.h')

diff --git a/googletest/include/gtest/gtest-printers.h b/googletest/include/gtest/gtest-printers.h
index fad4e692..54674697 100644
--- a/googletest/include/gtest/gtest-printers.h
+++ b/googletest/include/gtest/gtest-printers.h
@@ -104,14 +104,12 @@
 #include <ostream>  // NOLINT
 #include <sstream>
 #include <string>
+#include <tuple>
+#include <type_traits>
 #include <utility>
 #include <vector>
-#include "gtest/internal/gtest-port.h"
 #include "gtest/internal/gtest-internal.h"
-
-#if GTEST_HAS_STD_TUPLE_
-# include <tuple>
-#endif
+#include "gtest/internal/gtest-port.h"
 
 #if GTEST_HAS_ABSL
 #include "absl/strings/string_view.h"
@@ -643,95 +641,31 @@ void PrintTo(std::reference_wrapper<T> ref, ::std::ostream* os) {
   PrintTo(ref.get(), os);
 }
 
-#if GTEST_HAS_TR1_TUPLE || GTEST_HAS_STD_TUPLE_
 // Helper function for printing a tuple.  T must be instantiated with
 // a tuple type.
 template <typename T>
-void PrintTupleTo(const T& t, ::std::ostream* os);
-#endif  // GTEST_HAS_TR1_TUPLE || GTEST_HAS_STD_TUPLE_
-
-#if GTEST_HAS_TR1_TUPLE
-// Overload for ::std::tr1::tuple.  Needed for printing function arguments,
-// which are packed as tuples.
-
-// Overloaded PrintTo() for tuples of various arities.  We support
-// tuples of up-to 10 fields.  The following implementation works
-// regardless of whether tr1::tuple is implemented using the
-// non-standard variadic template feature or not.
-
-inline void PrintTo(const ::std::tr1::tuple<>& t, ::std::ostream* os) {
-  PrintTupleTo(t, os);
-}
-
-template <typename T1>
-void PrintTo(const ::std::tr1::tuple<T1>& t, ::std::ostream* os) {
-  PrintTupleTo(t, os);
-}
-
-template <typename T1, typename T2>
-void PrintTo(const ::std::tr1::tuple<T1, T2>& t, ::std::ostream* os) {
-  PrintTupleTo(t, os);
-}
-
-template <typename T1, typename T2, typename T3>
-void PrintTo(const ::std::tr1::tuple<T1, T2, T3>& t, ::std::ostream* os) {
-  PrintTupleTo(t, os);
-}
-
-template <typename T1, typename T2, typename T3, typename T4>
-void PrintTo(const ::std::tr1::tuple<T1, T2, T3, T4>& t, ::std::ostream* os) {
-  PrintTupleTo(t, os);
-}
-
-template <typename T1, typename T2, typename T3, typename T4, typename T5>
-void PrintTo(const ::std::tr1::tuple<T1, T2, T3, T4, T5>& t,
-             ::std::ostream* os) {
-  PrintTupleTo(t, os);
-}
-
-template <typename T1, typename T2, typename T3, typename T4, typename T5,
-          typename T6>
-void PrintTo(const ::std::tr1::tuple<T1, T2, T3, T4, T5, T6>& t,
-             ::std::ostream* os) {
-  PrintTupleTo(t, os);
-}
-
-template <typename T1, typename T2, typename T3, typename T4, typename T5,
-          typename T6, typename T7>
-void PrintTo(const ::std::tr1::tuple<T1, T2, T3, T4, T5, T6, T7>& t,
-             ::std::ostream* os) {
-  PrintTupleTo(t, os);
-}
-
-template <typename T1, typename T2, typename T3, typename T4, typename T5,
-          typename T6, typename T7, typename T8>
-void PrintTo(const ::std::tr1::tuple<T1, T2, T3, T4, T5, T6, T7, T8>& t,
-             ::std::ostream* os) {
-  PrintTupleTo(t, os);
-}
-
-template <typename T1, typename T2, typename T3, typename T4, typename T5,
-          typename T6, typename T7, typename T8, typename T9>
-void PrintTo(const ::std::tr1::tuple<T1, T2, T3, T4, T5, T6, T7, T8, T9>& t,
-             ::std::ostream* os) {
-  PrintTupleTo(t, os);
-}
-
-template <typename T1, typename T2, typename T3, typename T4, typename T5,
-          typename T6, typename T7, typename T8, typename T9, typename T10>
-void PrintTo(
-    const ::std::tr1::tuple<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>& t,
-    ::std::ostream* os) {
-  PrintTupleTo(t, os);
+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);
 }
-#endif  // GTEST_HAS_TR1_TUPLE
 
-#if GTEST_HAS_STD_TUPLE_
 template <typename... Types>
 void PrintTo(const ::std::tuple<Types...>& t, ::std::ostream* os) {
-  PrintTupleTo(t, os);
+  *os << "(";
+  PrintTupleTo(t, std::integral_constant<size_t, sizeof...(Types)>(), os);
+  *os << ")";
 }
-#endif  // GTEST_HAS_STD_TUPLE_
 
 // Overload for std::pair.
 template <typename T1, typename T2>
@@ -962,109 +896,20 @@ void UniversalPrint(const T& value, ::std::ostream* os) {
 
 typedef ::std::vector< ::std::string> Strings;
 
-// TuplePolicy<TupleT> must provide:
-// - tuple_size
-//     size of tuple TupleT.
-// - get<size_t I>(const TupleT& t)
-//     static function extracting element I of tuple TupleT.
-// - tuple_element<size_t I>::type
-//     type of element I of tuple TupleT.
-template <typename TupleT>
-struct TuplePolicy;
-
-#if GTEST_HAS_TR1_TUPLE
-template <typename TupleT>
-struct TuplePolicy {
-  typedef TupleT Tuple;
-  static const size_t tuple_size = ::std::tr1::tuple_size<Tuple>::value;
-
-  template <size_t I>
-  struct tuple_element : ::std::tr1::tuple_element<static_cast<int>(I), Tuple> {
-  };
-
-  template <size_t I>
-  static typename AddReference<const typename ::std::tr1::tuple_element<
-      static_cast<int>(I), Tuple>::type>::type
-  get(const Tuple& tuple) {
-    return ::std::tr1::get<I>(tuple);
-  }
-};
-template <typename TupleT>
-const size_t TuplePolicy<TupleT>::tuple_size;
-#endif  // GTEST_HAS_TR1_TUPLE
-
-#if GTEST_HAS_STD_TUPLE_
-template <typename... Types>
-struct TuplePolicy< ::std::tuple<Types...> > {
-  typedef ::std::tuple<Types...> Tuple;
-  static const size_t tuple_size = ::std::tuple_size<Tuple>::value;
-
-  template <size_t I>
-  struct tuple_element : ::std::tuple_element<I, Tuple> {};
-
-  template <size_t I>
-  static const typename ::std::tuple_element<I, Tuple>::type& get(
-      const Tuple& tuple) {
-    return ::std::get<I>(tuple);
-  }
-};
-template <typename... Types>
-const size_t TuplePolicy< ::std::tuple<Types...> >::tuple_size;
-#endif  // GTEST_HAS_STD_TUPLE_
-
-#if GTEST_HAS_TR1_TUPLE || GTEST_HAS_STD_TUPLE_
-// This helper template allows PrintTo() for tuples and
-// UniversalTersePrintTupleFieldsToStrings() to be defined by
-// induction on the number of tuple fields.  The idea is that
-// TuplePrefixPrinter<N>::PrintPrefixTo(t, os) prints the first N
-// fields in tuple t, and can be defined in terms of
-// TuplePrefixPrinter<N - 1>.
-//
-// The inductive case.
-template <size_t N>
-struct TuplePrefixPrinter {
-  // Prints the first N fields of a tuple.
-  template <typename Tuple>
-  static void PrintPrefixTo(const Tuple& t, ::std::ostream* os) {
-    TuplePrefixPrinter<N - 1>::PrintPrefixTo(t, os);
-    GTEST_INTENTIONAL_CONST_COND_PUSH_()
-    if (N > 1) {
-    GTEST_INTENTIONAL_CONST_COND_POP_()
-      *os << ", ";
-    }
-    UniversalPrinter<
-        typename TuplePolicy<Tuple>::template tuple_element<N - 1>::type>
-        ::Print(TuplePolicy<Tuple>::template get<N - 1>(t), os);
-  }
-
   // Tersely prints the first N fields of a tuple to a string vector,
   // one element for each field.
-  template <typename Tuple>
-  static void TersePrintPrefixToStrings(const Tuple& t, Strings* strings) {
-    TuplePrefixPrinter<N - 1>::TersePrintPrefixToStrings(t, strings);
-    ::std::stringstream ss;
-    UniversalTersePrint(TuplePolicy<Tuple>::template get<N - 1>(t), &ss);
-    strings->push_back(ss.str());
-  }
-};
-
-// Base case.
-template <>
-struct TuplePrefixPrinter<0> {
-  template <typename Tuple>
-  static void PrintPrefixTo(const Tuple&, ::std::ostream*) {}
-
-  template <typename Tuple>
-  static void TersePrintPrefixToStrings(const Tuple&, Strings*) {}
-};
-
-// Helper function for printing a tuple.
-// Tuple must be either std::tr1::tuple or std::tuple type.
 template <typename Tuple>
-void PrintTupleTo(const Tuple& t, ::std::ostream* os) {
-  *os << "(";
-  TuplePrefixPrinter<TuplePolicy<Tuple>::tuple_size>::PrintPrefixTo(t, os);
-  *os << ")";
+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
@@ -1073,11 +918,11 @@ void PrintTupleTo(const Tuple& t, ::std::ostream* os) {
 template <typename Tuple>
 Strings UniversalTersePrintTupleFieldsToStrings(const Tuple& value) {
   Strings result;
-  TuplePrefixPrinter<TuplePolicy<Tuple>::tuple_size>::
-      TersePrintPrefixToStrings(value, &result);
+  TersePrintPrefixToStrings(
+      value, std::integral_constant<size_t, std::tuple_size<Tuple>::value>(),
+      &result);
   return result;
 }
-#endif  // GTEST_HAS_TR1_TUPLE || GTEST_HAS_STD_TUPLE_
 
 }  // namespace internal
 
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