Export of internal Abseil changes

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20b3acaff75d05315f272747956b01405adccafb by Greg Falcon <gfalcon@google.com>:

Re-import of CCTZ from GitHub, with new ABSL_NAMESPACE_ transform applied.

PiperOrigin-RevId: 285564474

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4d9e3fcabcea33c8b0b69f094ad2eddc0fa19557 by Derek Mauro <dmauro@google.com>:

Moves the disabling of a warning to before the function begins.

MSVC apparently requires this for warnings in the range 4700-4999.
https://docs.microsoft.com/en-us/cpp/preprocessor/warning?redirectedfrom=MSDN&view=vs-2019

PiperOrigin-RevId: 285516232

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4a060cbeda76e89693c50276ae5b62cbf0fff39a by Derek Mauro <dmauro@google.com>:

MSVC: Fixes uniform_real_distribution_test in opt mode

Disables a constant arithmetic overflow warning in a test that tests
the behavior on overflow. This should be tested because a user might
have this warning disabled.

PiperOrigin-RevId: 285452242

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548ab2f4cbe59bd6f6bf493af4f9ea765c4fa949 by Andy Soffer <asoffer@google.com>:

Release absl::bind_front, a C++11-compliant work-alike type for the C++20
std::bind_front.

PiperOrigin-RevId: 285247872
GitOrigin-RevId: 20b3acaff75d05315f272747956b01405adccafb
Change-Id: I00fe45939246cba9bfc7be375d67787d2eb57cd3

1 files changed, 231 insertions, 0 deletions

diff --git a/absl/functional/bind_front_test.cc b/absl/functional/bind_front_test.cc
new file mode 100644
index 000000000000..4801a81caf0d
--- /dev/null
+++ b/absl/functional/bind_front_test.cc
@@ -0,0 +1,231 @@
+// Copyright 2018 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/functional/bind_front.h"
+
+#include <stddef.h>
+
+#include <functional>
+#include <memory>
+#include <string>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/memory/memory.h"
+
+namespace {
+
+char CharAt(const char* s, size_t index) { return s[index]; }
+
+TEST(BindTest, Basics) {
+  EXPECT_EQ('C', absl::bind_front(CharAt)("ABC", 2));
+  EXPECT_EQ('C', absl::bind_front(CharAt, "ABC")(2));
+  EXPECT_EQ('C', absl::bind_front(CharAt, "ABC", 2)());
+}
+
+TEST(BindTest, Lambda) {
+  auto lambda = [](int x, int y, int z) { return x + y + z; };
+  EXPECT_EQ(6, absl::bind_front(lambda)(1, 2, 3));
+  EXPECT_EQ(6, absl::bind_front(lambda, 1)(2, 3));
+  EXPECT_EQ(6, absl::bind_front(lambda, 1, 2)(3));
+  EXPECT_EQ(6, absl::bind_front(lambda, 1, 2, 3)());
+}
+
+struct Functor {
+  std::string operator()() & { return "&"; }
+  std::string operator()() const& { return "const&"; }
+  std::string operator()() && { return "&&"; }
+  std::string operator()() const&& { return "const&&"; }
+};
+
+TEST(BindTest, PerfectForwardingOfBoundArgs) {
+  auto f = absl::bind_front(Functor());
+  const auto& cf = f;
+  EXPECT_EQ("&", f());
+  EXPECT_EQ("const&", cf());
+  EXPECT_EQ("&&", std::move(f)());
+  EXPECT_EQ("const&&", std::move(cf)());
+}
+
+struct ArgDescribe {
+  std::string operator()(int&) const { return "&"; }             // NOLINT
+  std::string operator()(const int&) const { return "const&"; }  // NOLINT
+  std::string operator()(int&&) const { return "&&"; }
+  std::string operator()(const int&&) const { return "const&&"; }
+};
+
+TEST(BindTest, PerfectForwardingOfFreeArgs) {
+  ArgDescribe f;
+  int i;
+  EXPECT_EQ("&", absl::bind_front(f)(static_cast<int&>(i)));
+  EXPECT_EQ("const&", absl::bind_front(f)(static_cast<const int&>(i)));
+  EXPECT_EQ("&&", absl::bind_front(f)(static_cast<int&&>(i)));
+  EXPECT_EQ("const&&", absl::bind_front(f)(static_cast<const int&&>(i)));
+}
+
+struct NonCopyableFunctor {
+  NonCopyableFunctor() = default;
+  NonCopyableFunctor(const NonCopyableFunctor&) = delete;
+  NonCopyableFunctor& operator=(const NonCopyableFunctor&) = delete;
+  const NonCopyableFunctor* operator()() const { return this; }
+};
+
+TEST(BindTest, RefToFunctor) {
+  // It won't copy/move the functor and use the original object.
+  NonCopyableFunctor ncf;
+  auto bound_ncf = absl::bind_front(std::ref(ncf));
+  auto bound_ncf_copy = bound_ncf;
+  EXPECT_EQ(&ncf, bound_ncf_copy());
+}
+
+struct Struct {
+  std::string value;
+};
+
+TEST(BindTest, StoreByCopy) {
+  Struct s = {"hello"};
+  auto f = absl::bind_front(&Struct::value, s);
+  auto g = f;
+  EXPECT_EQ("hello", f());
+  EXPECT_EQ("hello", g());
+  EXPECT_NE(&s.value, &f());
+  EXPECT_NE(&s.value, &g());
+  EXPECT_NE(&g(), &f());
+}
+
+struct NonCopyable {
+  explicit NonCopyable(const std::string& s) : value(s) {}
+  NonCopyable(const NonCopyable&) = delete;
+  NonCopyable& operator=(const NonCopyable&) = delete;
+
+  std::string value;
+};
+
+const std::string& GetNonCopyableValue(const NonCopyable& n) { return n.value; }
+
+TEST(BindTest, StoreByRef) {
+  NonCopyable s("hello");
+  auto f = absl::bind_front(&GetNonCopyableValue, std::ref(s));
+  EXPECT_EQ("hello", f());
+  EXPECT_EQ(&s.value, &f());
+  auto g = std::move(f);  // NOLINT
+  EXPECT_EQ("hello", g());
+  EXPECT_EQ(&s.value, &g());
+  s.value = "goodbye";
+  EXPECT_EQ("goodbye", g());
+}
+
+TEST(BindTest, StoreByCRef) {
+  NonCopyable s("hello");
+  auto f = absl::bind_front(&GetNonCopyableValue, std::cref(s));
+  EXPECT_EQ("hello", f());
+  EXPECT_EQ(&s.value, &f());
+  auto g = std::move(f);  // NOLINT
+  EXPECT_EQ("hello", g());
+  EXPECT_EQ(&s.value, &g());
+  s.value = "goodbye";
+  EXPECT_EQ("goodbye", g());
+}
+
+const std::string& GetNonCopyableValueByWrapper(
+    std::reference_wrapper<NonCopyable> n) {
+  return n.get().value;
+}
+
+TEST(BindTest, StoreByRefInvokeByWrapper) {
+  NonCopyable s("hello");
+  auto f = absl::bind_front(GetNonCopyableValueByWrapper, std::ref(s));
+  EXPECT_EQ("hello", f());
+  EXPECT_EQ(&s.value, &f());
+  auto g = std::move(f);
+  EXPECT_EQ("hello", g());
+  EXPECT_EQ(&s.value, &g());
+  s.value = "goodbye";
+  EXPECT_EQ("goodbye", g());
+}
+
+TEST(BindTest, StoreByPointer) {
+  NonCopyable s("hello");
+  auto f = absl::bind_front(&NonCopyable::value, &s);
+  EXPECT_EQ("hello", f());
+  EXPECT_EQ(&s.value, &f());
+  auto g = std::move(f);
+  EXPECT_EQ("hello", g());
+  EXPECT_EQ(&s.value, &g());
+}
+
+int Sink(std::unique_ptr<int> p) {
+  return *p;
+}
+
+std::unique_ptr<int> Factory(int n) { return absl::make_unique<int>(n); }
+
+TEST(BindTest, NonCopyableArg) {
+  EXPECT_EQ(42, absl::bind_front(Sink)(absl::make_unique<int>(42)));
+  EXPECT_EQ(42, absl::bind_front(Sink, absl::make_unique<int>(42))());
+}
+
+TEST(BindTest, NonCopyableResult) {
+  EXPECT_THAT(absl::bind_front(Factory)(42), ::testing::Pointee(42));
+  EXPECT_THAT(absl::bind_front(Factory, 42)(), ::testing::Pointee(42));
+}
+
+// is_copy_constructible<FalseCopyable<unique_ptr<T>> is true but an attempt to
+// instantiate the copy constructor leads to a compile error. This is similar
+// to how standard containers behave.
+template <class T>
+struct FalseCopyable {
+  FalseCopyable() {}
+  FalseCopyable(const FalseCopyable& other) : m(other.m) {}
+  FalseCopyable(FalseCopyable&& other) : m(std::move(other.m)) {}
+  T m;
+};
+
+int GetMember(FalseCopyable<std::unique_ptr<int>> x) { return *x.m; }
+
+TEST(BindTest, WrappedMoveOnly) {
+  FalseCopyable<std::unique_ptr<int>> x;
+  x.m = absl::make_unique<int>(42);
+  auto f = absl::bind_front(&GetMember, std::move(x));
+  EXPECT_EQ(42, std::move(f)());
+}
+
+int Plus(int a, int b) { return a + b; }
+
+TEST(BindTest, ConstExpr) {
+  constexpr auto f = absl::bind_front(CharAt);
+  EXPECT_EQ(f("ABC", 1), 'B');
+  static constexpr int five = 5;
+  constexpr auto plus5 = absl::bind_front(Plus, five);
+  EXPECT_EQ(plus5(1), 6);
+
+  // There seems to be a bug in MSVC dealing constexpr construction of
+  // char[]. Notice 'plus5' above; 'int' works just fine.
+#if !(defined(_MSC_VER) && _MSC_VER < 1910)
+  static constexpr char data[] = "DEF";
+  constexpr auto g = absl::bind_front(CharAt, data);
+  EXPECT_EQ(g(1), 'E');
+#endif
+}
+
+struct ManglingCall {
+  int operator()(int, double, std::string) const { return 0; }
+};
+
+TEST(BindTest, Mangling) {
+  // We just want to generate a particular instantiation to see its mangling.
+  absl::bind_front(ManglingCall{}, 1, 3.3)("A");
+}
+
+}  // namespace