1 files changed, 65 insertions, 9 deletions

diff --git a/absl/memory/memory.h b/absl/memory/memory.h
index 54ff2182..34cfb285 100644
--- a/absl/memory/memory.h
+++ b/absl/memory/memory.h
@@ -34,22 +34,36 @@
 #include "absl/meta/type_traits.h"
 
 namespace absl {
-inline namespace lts_2018_06_20 {
+inline namespace lts_2018_12_18 {
 
 // -----------------------------------------------------------------------------
 // Function Template: WrapUnique()
 // -----------------------------------------------------------------------------
 //
-//  Adopts ownership from a raw pointer and transfers it to the returned
-//  `std::unique_ptr`, whose type is deduced. DO NOT specify the template type T
-//  when calling WrapUnique.
+// Adopts ownership from a raw pointer and transfers it to the returned
+// `std::unique_ptr`, whose type is deduced. Because of this deduction, *do not*
+// specify the template type `T` when calling `WrapUnique`.
 //
 // Example:
 //   X* NewX(int, int);
 //   auto x = WrapUnique(NewX(1, 2));  // 'x' is std::unique_ptr<X>.
 //
-// `absl::WrapUnique` is useful for capturing the output of a raw pointer
-// factory. However, prefer 'absl::make_unique<T>(args...) over
+// The purpose of WrapUnique is to automatically deduce the pointer type. If you
+// wish to make the type explicit, for readability reasons or because you prefer
+// to use a base-class pointer rather than a derived one, just use
+// `std::unique_ptr` directly.
+//
+// Example:
+//   X* Factory(int, int);
+//   auto x = std::unique_ptr<X>(Factory(1, 2));
+//                  - or -
+//   std::unique_ptr<X> x(Factory(1, 2));
+//
+// This has the added advantage of working whether Factory returns a raw
+// pointer or a `std::unique_ptr`.
+//
+// While `absl::WrapUnique` is useful for capturing the output of a raw
+// pointer factory, prefer 'absl::make_unique<T>(args...)' over
 // 'absl::WrapUnique(new T(args...))'.
 //
 //   auto x = WrapUnique(new X(1, 2));  // works, but nonideal.
@@ -84,7 +98,11 @@ struct MakeUniqueResult<T[N]> {
 
 }  // namespace memory_internal
 
-#if __cplusplus >= 201402L || defined(_MSC_VER)
+// gcc 4.8 has __cplusplus at 201301 but doesn't define make_unique.  Other
+// supported compilers either just define __cplusplus as 201103 but have
+// make_unique (msvc), or have make_unique whenever __cplusplus > 201103 (clang)
+#if (__cplusplus > 201103L || defined(_MSC_VER)) && \
+    !(defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ == 8)
 using std::make_unique;
 #else
 // -----------------------------------------------------------------------------
@@ -582,7 +600,7 @@ struct allocator_traits {
     return a.max_size();
   }
   static size_type max_size_impl(char, const Alloc&) {
-    return std::numeric_limits<size_type>::max() / sizeof(value_type);
+    return (std::numeric_limits<size_type>::max)() / sizeof(value_type);
   }
 
   template <typename A>
@@ -637,7 +655,45 @@ struct default_allocator_is_nothrow : std::true_type {};
 struct default_allocator_is_nothrow : std::false_type {};
 #endif
 
-}  // inline namespace lts_2018_06_20
+namespace memory_internal {
+template <typename Allocator, typename Iterator, typename... Args>
+void ConstructRange(Allocator& alloc, Iterator first, Iterator last,
+                    const Args&... args) {
+  for (Iterator cur = first; cur != last; ++cur) {
+    ABSL_INTERNAL_TRY {
+      std::allocator_traits<Allocator>::construct(alloc, std::addressof(*cur),
+                                                  args...);
+    }
+    ABSL_INTERNAL_CATCH_ANY {
+      while (cur != first) {
+        --cur;
+        std::allocator_traits<Allocator>::destroy(alloc, std::addressof(*cur));
+      }
+      ABSL_INTERNAL_RETHROW;
+    }
+  }
+}
+
+template <typename Allocator, typename Iterator, typename InputIterator>
+void CopyRange(Allocator& alloc, Iterator destination, InputIterator first,
+               InputIterator last) {
+  for (Iterator cur = destination; first != last;
+       static_cast<void>(++cur), static_cast<void>(++first)) {
+    ABSL_INTERNAL_TRY {
+      std::allocator_traits<Allocator>::construct(alloc, std::addressof(*cur),
+                                                  *first);
+    }
+    ABSL_INTERNAL_CATCH_ANY {
+      while (cur != destination) {
+        --cur;
+        std::allocator_traits<Allocator>::destroy(alloc, std::addressof(*cur));
+      }
+      ABSL_INTERNAL_RETHROW;
+    }
+  }
+}
+}  // namespace memory_internal
+}  // inline namespace lts_2018_12_18
 }  // namespace absl
 
 #endif  // ABSL_MEMORY_MEMORY_H_