Export of internal Abseil changes.

--
5a5dba4252e764e6737070bf0a31074bf23a3b41 by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 244898913

--
3eb7d5b445ffbf08a104e39cd15aecf568417333 by Matt Calabrese <calabrese@google.com>:

Introduce absl::is_trivially_move_constructible and absl::is_trivially_move_assignable, and update the absl::is_trivially_copy_constructible and absl::is_trivially_copy_assignable traits to use similar techniques (should now be closer to the standard behavior).

PiperOrigin-RevId: 244859015

--
7da05a24fa786cab3985de0c39a186d73dcbcfb5 by Abseil Team <absl-team@google.com>:

Fix misspellings in comments in raw_hash_set.h.

PiperOrigin-RevId: 244754700

--
5c057be96048f21473d5ec45005ab4dcd8dd354f by Derek Mauro <dmauro@google.com>:

Internal change

PiperOrigin-RevId: 244744239

--
592394e3c2e98f1238d3fb6fcb0d20c3e3739ba9 by Derek Mauro <dmauro@google.com>:

Limit the raw_hash_set prefetch test to x86-64.

PiperOrigin-RevId: 244737534

--
99ebe4e003633c8ff7838b035b31a827994879ef by Derek Mauro <dmauro@google.com>:

Workaround warning 4091 in an MSVC header.

PiperOrigin-RevId: 244701744

--
0aa23f09a32efe7985ee55b0217190f08da42477 by Abseil Team <absl-team@google.com>:

Fix comment typo.

PiperOrigin-RevId: 244659371

--
c6cdb87e9f28062c8daa29b3d8d68182ecc16383 by Derek Mauro <dmauro@google.com>:

Fix -Wundef warnings and support -Wundef.

PiperOrigin-RevId: 244244968

--
06b81245f7696b20c3c63b0618d33ac25e29cad6 by Abseil Team <absl-team@google.com>:

Fix a typo in inlined_vector.h.

PiperOrigin-RevId: 244230809

--
94877a2125d2cfe837384240e4d6551f39d737e4 by Greg Falcon <gfalcon@google.com>:

Fix sysinfo_test for emscripten.

PiperOrigin-RevId: 244198804

--
ec7783531ef7f9df2da37d341d61f7cb2bf843f0 by Shaindel Schwartz <shaindel@google.com>:

Import of CCTZ from GitHub.

Fixes #291.

PiperOrigin-RevId: 244184598

--
b652c14fa95ea206c217487ee713b11f5d1762b3 by Matt Calabrese <calabrese@google.com>:

Emulate the `in_place_index` and `in_place_type` variable templates such that they are syntactically usable in C++11 with `any` and `variant`. Also pull in the variable templates from namespace std when available.

The main observable differences here are:

1)
The types of `in_place_index_t<I>` and `in_place_type_t<T>` become function pointer types rather than structs when using the implementation that is not an alias of the std equivalents.

2)
The types of `in_place_index<I>` and `in_place_type<T>` are not directly `in_place_index_t<I>` and `in_place_type_t<T>`, but rather they become function types that decay to the corresponding function pointer types.

3)
The default constructor for `in_place_index_t` and `in_place_type_t` instantiations is no longer explicit, but for these templates I think that's less important than for something like `in_place_t` since the _type_t and _index_t versions basically never have their template parameter non-deduced when participating in overload resolution with conflicting candidates.

4) While idiomatic usage of `in_place_type_t` and `in_place_index_t` with std::variant and std::any should not be affected, there is the possibility that strange, non-idiomatic uses may be affected in the wild.

5) Default construction (rather than value-initialization) leads to a default-constructed pointer.

PiperOrigin-RevId: 244180003

--
b9ac5a96581837ffa24532117b7ea302a5569751 by Derek Mauro <dmauro@google.com>:

Fix MSVC debug assertion.

isprint is undefined for values not representable as unsigned char or
EOF.

PiperOrigin-RevId: 244083005

--
41758be6137c2f25e84b50f23938e49484be2903 by Shaindel Schwartz <shaindel@google.com>:

Update config settings for Apple platforms.

PiperOrigin-RevId: 244040587

--
c90df6a26db94b0305a0c954455a621542a89d91 by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 244024427

--
c71e9ceb89495354eca7d02bd905ffeaa9029aec by Derek Mauro <dmauro@google.com>:

Adds missing ABSL_DEFAULT_COPTS and ABSL_TEST_COPTS to CMakeLists.txt

Don't error on deprecated declarations in tests. It is completely
reasonable to test that code marked deprecated still works.

PiperOrigin-RevId: 244003941

--
e1326a96527a8ba9b8d120161545260da9c4562e by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 243990623

--
90b8e12934c7711e1bfcc0117d21288bf9220dee by Abseil Team <absl-team@google.com>:

Add variation of absl::Base64Escape/WebSafeBase64Escape that directly returns its result.

PiperOrigin-RevId: 243894308

--
317fef3344481ebc5c35712d42f5d8a0fa64dff4 by Abseil Team <absl-team@google.com>:

Enable raw logging in Emscripten builds.

PiperOrigin-RevId: 243893705
GitOrigin-RevId: 5a5dba4252e764e6737070bf0a31074bf23a3b41
Change-Id: I19293aab73cc98d9e9bf6a9fdc30819764adb9db

1 files changed, 106 insertions, 3 deletions

diff --git a/absl/meta/type_traits.h b/absl/meta/type_traits.h
index a8068e315ed3..c08e3754689b 100644
--- a/absl/meta/type_traits.h
+++ b/absl/meta/type_traits.h
@@ -43,8 +43,39 @@
 
 namespace absl {
 
+// Defined and documented later on in this file.
+template <typename T>
+struct is_trivially_move_assignable;
+
 namespace type_traits_internal {
 
+// Silence MSVC warnings about the destructor being defined as deleted.
+#if defined(_MSC_VER) && !defined(__GNUC__)
+#pragma warning(push)
+#pragma warning(disable : 4624)
+#endif  // defined(_MSC_VER) && !defined(__GNUC__)
+
+template <class T>
+union SingleMemberUnion {
+  T t;
+};
+
+// Restore the state of the destructor warning that was silenced above.
+#if defined(_MSC_VER) && !defined(__GNUC__)
+#pragma warning(pop)
+#endif  // defined(_MSC_VER) && !defined(__GNUC__)
+
+template <class T>
+struct IsTriviallyMoveAssignableReference : std::false_type {};
+
+template <class T>
+struct IsTriviallyMoveAssignableReference<T&>
+    : absl::is_trivially_move_assignable<T>::type {};
+
+template <class T>
+struct IsTriviallyMoveAssignableReference<T&&>
+    : absl::is_trivially_move_assignable<T>::type {};
+
 template <typename... Ts>
 struct VoidTImpl {
   using type = void;
@@ -275,6 +306,40 @@ struct is_trivially_default_constructible
 #endif  // ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE
 };
 
+// is_trivially_move_constructible()
+//
+// Determines whether the passed type `T` is trivially move constructible.
+//
+// This metafunction is designed to be a drop-in replacement for the C++11
+// `std::is_trivially_move_constructible()` metafunction for platforms that have
+// incomplete C++11 support (such as libstdc++ 4.x). On any platforms that do
+// fully support C++11, we check whether this yields the same result as the std
+// implementation.
+//
+// NOTE: `T obj(declval<T>());` needs to be well-formed and not call any
+// nontrivial operation.  Nontrivially destructible types will cause the
+// expression to be nontrivial.
+template <typename T>
+struct is_trivially_move_constructible
+    : std::conditional<
+          std::is_object<T>::value && !std::is_array<T>::value,
+          std::is_move_constructible<
+              type_traits_internal::SingleMemberUnion<T>>,
+          std::is_reference<T>>::type::type {
+#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE
+ private:
+  static constexpr bool compliant =
+      std::is_trivially_move_constructible<T>::value ==
+      is_trivially_move_constructible::value;
+  static_assert(compliant || std::is_trivially_move_constructible<T>::value,
+                "Not compliant with std::is_trivially_move_constructible; "
+                "Standard: false, Implementation: true");
+  static_assert(compliant || !std::is_trivially_move_constructible<T>::value,
+                "Not compliant with std::is_trivially_move_constructible; "
+                "Standard: true, Implementation: false");
+#endif  // ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE
+};
+
 // is_trivially_copy_constructible()
 //
 // Determines whether the passed type `T` is trivially copy constructible.
@@ -290,9 +355,11 @@ struct is_trivially_default_constructible
 // expression to be nontrivial.
 template <typename T>
 struct is_trivially_copy_constructible
-    : std::integral_constant<bool, __has_trivial_copy(T) &&
-                                   std::is_copy_constructible<T>::value &&
-                                   is_trivially_destructible<T>::value> {
+    : std::conditional<
+          std::is_object<T>::value && !std::is_array<T>::value,
+          std::is_copy_constructible<
+              type_traits_internal::SingleMemberUnion<T>>,
+          std::is_lvalue_reference<T>>::type::type {
 #ifdef ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE
  private:
   static constexpr bool compliant =
@@ -307,6 +374,42 @@ struct is_trivially_copy_constructible
 #endif  // ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE
 };
 
+// is_trivially_move_assignable()
+//
+// Determines whether the passed type `T` is trivially move assignable.
+//
+// This metafunction is designed to be a drop-in replacement for the C++11
+// `std::is_trivially_move_assignable()` metafunction for platforms that have
+// incomplete C++11 support (such as libstdc++ 4.x). On any platforms that do
+// fully support C++11, we check whether this yields the same result as the std
+// implementation.
+//
+// NOTE: `is_assignable<T, U>::value` is `true` if the expression
+// `declval<T>() = declval<U>()` is well-formed when treated as an unevaluated
+// operand. `is_trivially_assignable<T, U>` requires the assignment to call no
+// operation that is not trivial. `is_trivially_copy_assignable<T>` is simply
+// `is_trivially_assignable<T&, T>`.
+template <typename T>
+struct is_trivially_move_assignable
+    : std::conditional<
+          std::is_object<T>::value && !std::is_array<T>::value,
+          std::is_move_assignable<type_traits_internal::SingleMemberUnion<T>>,
+          type_traits_internal::IsTriviallyMoveAssignableReference<T>>::type::
+          type {
+#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE
+ private:
+  static constexpr bool compliant =
+      std::is_trivially_move_assignable<T>::value ==
+      is_trivially_move_assignable::value;
+  static_assert(compliant || std::is_trivially_move_assignable<T>::value,
+                "Not compliant with std::is_trivially_move_assignable; "
+                "Standard: false, Implementation: true");
+  static_assert(compliant || !std::is_trivially_move_assignable<T>::value,
+                "Not compliant with std::is_trivially_move_assignable; "
+                "Standard: true, Implementation: false");
+#endif  // ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE
+};
+
 // is_trivially_copy_assignable()
 //
 // Determines whether the passed type `T` is trivially copy assignable.