Squashed 'third_party/abseil/' content from commit ddf8e52a2
Change-Id: I330cdc687395c6605ad027b855e313ff4a2059e9
git-subtree-dir: third_party/abseil
git-subtree-split: ddf8e52a2918dd0ccec75d3e2426125fa3926724
diff --git a/absl/utility/BUILD.bazel b/absl/utility/BUILD.bazel
new file mode 100644
index 0000000..6881f93
--- /dev/null
+++ b/absl/utility/BUILD.bazel
@@ -0,0 +1,55 @@
+#
+# Copyright 2019 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.
+#
+
+load("@rules_cc//cc:defs.bzl", "cc_library", "cc_test")
+load(
+ "//absl:copts/configure_copts.bzl",
+ "ABSL_DEFAULT_COPTS",
+ "ABSL_DEFAULT_LINKOPTS",
+ "ABSL_TEST_COPTS",
+)
+
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"]) # Apache 2.0
+
+cc_library(
+ name = "utility",
+ hdrs = [
+ "utility.h",
+ ],
+ copts = ABSL_DEFAULT_COPTS,
+ linkopts = ABSL_DEFAULT_LINKOPTS,
+ deps = [
+ "//absl/base:base_internal",
+ "//absl/base:config",
+ "//absl/meta:type_traits",
+ ],
+)
+
+cc_test(
+ name = "utility_test",
+ srcs = ["utility_test.cc"],
+ copts = ABSL_TEST_COPTS,
+ linkopts = ABSL_DEFAULT_LINKOPTS,
+ deps = [
+ ":utility",
+ "//absl/base:core_headers",
+ "//absl/memory",
+ "//absl/strings",
+ "@com_google_googletest//:gtest_main",
+ ],
+)
diff --git a/absl/utility/CMakeLists.txt b/absl/utility/CMakeLists.txt
new file mode 100644
index 0000000..e1edd19
--- /dev/null
+++ b/absl/utility/CMakeLists.txt
@@ -0,0 +1,44 @@
+#
+# Copyright 2017 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.
+#
+
+absl_cc_library(
+ NAME
+ utility
+ HDRS
+ "utility.h"
+ COPTS
+ ${ABSL_DEFAULT_COPTS}
+ DEPS
+ absl::base_internal
+ absl::config
+ absl::type_traits
+ PUBLIC
+)
+
+absl_cc_test(
+ NAME
+ utility_test
+ SRCS
+ "utility_test.cc"
+ COPTS
+ ${ABSL_TEST_COPTS}
+ DEPS
+ absl::utility
+ absl::core_headers
+ absl::memory
+ absl::strings
+ gmock_main
+)
diff --git a/absl/utility/utility.h b/absl/utility/utility.h
new file mode 100644
index 0000000..eef8fb4
--- /dev/null
+++ b/absl/utility/utility.h
@@ -0,0 +1,348 @@
+// Copyright 2017 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.
+//
+// This header file contains C++11 versions of standard <utility> header
+// abstractions available within C++14 and C++17, and are designed to be drop-in
+// replacement for code compliant with C++14 and C++17.
+//
+// The following abstractions are defined:
+//
+// * integer_sequence<T, Ints...> == std::integer_sequence<T, Ints...>
+// * index_sequence<Ints...> == std::index_sequence<Ints...>
+// * make_integer_sequence<T, N> == std::make_integer_sequence<T, N>
+// * make_index_sequence<N> == std::make_index_sequence<N>
+// * index_sequence_for<Ts...> == std::index_sequence_for<Ts...>
+// * apply<Functor, Tuple> == std::apply<Functor, Tuple>
+// * exchange<T> == std::exchange<T>
+// * make_from_tuple<T> == std::make_from_tuple<T>
+//
+// This header file also provides the tag types `in_place_t`, `in_place_type_t`,
+// and `in_place_index_t`, as well as the constant `in_place`, and
+// `constexpr` `std::move()` and `std::forward()` implementations in C++11.
+//
+// References:
+//
+// https://en.cppreference.com/w/cpp/utility/integer_sequence
+// https://en.cppreference.com/w/cpp/utility/apply
+// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3658.html
+
+#ifndef ABSL_UTILITY_UTILITY_H_
+#define ABSL_UTILITY_UTILITY_H_
+
+#include <cstddef>
+#include <cstdlib>
+#include <tuple>
+#include <utility>
+
+#include "absl/base/config.h"
+#include "absl/base/internal/inline_variable.h"
+#include "absl/base/internal/invoke.h"
+#include "absl/meta/type_traits.h"
+
+namespace absl {
+
+// integer_sequence
+//
+// Class template representing a compile-time integer sequence. An instantiation
+// of `integer_sequence<T, Ints...>` has a sequence of integers encoded in its
+// type through its template arguments (which is a common need when
+// working with C++11 variadic templates). `absl::integer_sequence` is designed
+// to be a drop-in replacement for C++14's `std::integer_sequence`.
+//
+// Example:
+//
+// template< class T, T... Ints >
+// void user_function(integer_sequence<T, Ints...>);
+//
+// int main()
+// {
+// // user_function's `T` will be deduced to `int` and `Ints...`
+// // will be deduced to `0, 1, 2, 3, 4`.
+// user_function(make_integer_sequence<int, 5>());
+// }
+template <typename T, T... Ints>
+struct integer_sequence {
+ using value_type = T;
+ static constexpr size_t size() noexcept { return sizeof...(Ints); }
+};
+
+// index_sequence
+//
+// A helper template for an `integer_sequence` of `size_t`,
+// `absl::index_sequence` is designed to be a drop-in replacement for C++14's
+// `std::index_sequence`.
+template <size_t... Ints>
+using index_sequence = integer_sequence<size_t, Ints...>;
+
+namespace utility_internal {
+
+template <typename Seq, size_t SeqSize, size_t Rem>
+struct Extend;
+
+// Note that SeqSize == sizeof...(Ints). It's passed explicitly for efficiency.
+template <typename T, T... Ints, size_t SeqSize>
+struct Extend<integer_sequence<T, Ints...>, SeqSize, 0> {
+ using type = integer_sequence<T, Ints..., (Ints + SeqSize)...>;
+};
+
+template <typename T, T... Ints, size_t SeqSize>
+struct Extend<integer_sequence<T, Ints...>, SeqSize, 1> {
+ using type = integer_sequence<T, Ints..., (Ints + SeqSize)..., 2 * SeqSize>;
+};
+
+// Recursion helper for 'make_integer_sequence<T, N>'.
+// 'Gen<T, N>::type' is an alias for 'integer_sequence<T, 0, 1, ... N-1>'.
+template <typename T, size_t N>
+struct Gen {
+ using type =
+ typename Extend<typename Gen<T, N / 2>::type, N / 2, N % 2>::type;
+};
+
+template <typename T>
+struct Gen<T, 0> {
+ using type = integer_sequence<T>;
+};
+
+template <typename T>
+struct InPlaceTypeTag {
+ explicit InPlaceTypeTag() = delete;
+ InPlaceTypeTag(const InPlaceTypeTag&) = delete;
+ InPlaceTypeTag& operator=(const InPlaceTypeTag&) = delete;
+};
+
+template <size_t I>
+struct InPlaceIndexTag {
+ explicit InPlaceIndexTag() = delete;
+ InPlaceIndexTag(const InPlaceIndexTag&) = delete;
+ InPlaceIndexTag& operator=(const InPlaceIndexTag&) = delete;
+};
+
+} // namespace utility_internal
+
+// Compile-time sequences of integers
+
+// make_integer_sequence
+//
+// This template alias is equivalent to
+// `integer_sequence<int, 0, 1, ..., N-1>`, and is designed to be a drop-in
+// replacement for C++14's `std::make_integer_sequence`.
+template <typename T, T N>
+using make_integer_sequence = typename utility_internal::Gen<T, N>::type;
+
+// make_index_sequence
+//
+// This template alias is equivalent to `index_sequence<0, 1, ..., N-1>`,
+// and is designed to be a drop-in replacement for C++14's
+// `std::make_index_sequence`.
+template <size_t N>
+using make_index_sequence = make_integer_sequence<size_t, N>;
+
+// index_sequence_for
+//
+// Converts a typename pack into an index sequence of the same length, and
+// is designed to be a drop-in replacement for C++14's
+// `std::index_sequence_for()`
+template <typename... Ts>
+using index_sequence_for = make_index_sequence<sizeof...(Ts)>;
+
+// Tag types
+
+#ifdef ABSL_HAVE_STD_OPTIONAL
+
+using std::in_place_t;
+using std::in_place;
+
+#else // ABSL_HAVE_STD_OPTIONAL
+
+// in_place_t
+//
+// Tag type used to specify in-place construction, such as with
+// `absl::optional`, designed to be a drop-in replacement for C++17's
+// `std::in_place_t`.
+struct in_place_t {};
+
+ABSL_INTERNAL_INLINE_CONSTEXPR(in_place_t, in_place, {});
+
+#endif // ABSL_HAVE_STD_OPTIONAL
+
+#if defined(ABSL_HAVE_STD_ANY) || defined(ABSL_HAVE_STD_VARIANT)
+using std::in_place_type;
+using std::in_place_type_t;
+#else
+
+// in_place_type_t
+//
+// Tag type used for in-place construction when the type to construct needs to
+// be specified, such as with `absl::any`, designed to be a drop-in replacement
+// for C++17's `std::in_place_type_t`.
+template <typename T>
+using in_place_type_t = void (*)(utility_internal::InPlaceTypeTag<T>);
+
+template <typename T>
+void in_place_type(utility_internal::InPlaceTypeTag<T>) {}
+#endif // ABSL_HAVE_STD_ANY || ABSL_HAVE_STD_VARIANT
+
+#ifdef ABSL_HAVE_STD_VARIANT
+using std::in_place_index;
+using std::in_place_index_t;
+#else
+
+// in_place_index_t
+//
+// Tag type used for in-place construction when the type to construct needs to
+// be specified, such as with `absl::any`, designed to be a drop-in replacement
+// for C++17's `std::in_place_index_t`.
+template <size_t I>
+using in_place_index_t = void (*)(utility_internal::InPlaceIndexTag<I>);
+
+template <size_t I>
+void in_place_index(utility_internal::InPlaceIndexTag<I>) {}
+#endif // ABSL_HAVE_STD_VARIANT
+
+// Constexpr move and forward
+
+// move()
+//
+// A constexpr version of `std::move()`, designed to be a drop-in replacement
+// for C++14's `std::move()`.
+template <typename T>
+constexpr absl::remove_reference_t<T>&& move(T&& t) noexcept {
+ return static_cast<absl::remove_reference_t<T>&&>(t);
+}
+
+// forward()
+//
+// A constexpr version of `std::forward()`, designed to be a drop-in replacement
+// for C++14's `std::forward()`.
+template <typename T>
+constexpr T&& forward(
+ absl::remove_reference_t<T>& t) noexcept { // NOLINT(runtime/references)
+ return static_cast<T&&>(t);
+}
+
+namespace utility_internal {
+// Helper method for expanding tuple into a called method.
+template <typename Functor, typename Tuple, std::size_t... Indexes>
+auto apply_helper(Functor&& functor, Tuple&& t, index_sequence<Indexes...>)
+ -> decltype(absl::base_internal::Invoke(
+ absl::forward<Functor>(functor),
+ std::get<Indexes>(absl::forward<Tuple>(t))...)) {
+ return absl::base_internal::Invoke(
+ absl::forward<Functor>(functor),
+ std::get<Indexes>(absl::forward<Tuple>(t))...);
+}
+
+} // namespace utility_internal
+
+// apply
+//
+// Invokes a Callable using elements of a tuple as its arguments.
+// Each element of the tuple corresponds to an argument of the call (in order).
+// Both the Callable argument and the tuple argument are perfect-forwarded.
+// For member-function Callables, the first tuple element acts as the `this`
+// pointer. `absl::apply` is designed to be a drop-in replacement for C++17's
+// `std::apply`. Unlike C++17's `std::apply`, this is not currently `constexpr`.
+//
+// Example:
+//
+// class Foo {
+// public:
+// void Bar(int);
+// };
+// void user_function1(int, std::string);
+// void user_function2(std::unique_ptr<Foo>);
+// auto user_lambda = [](int, int) {};
+//
+// int main()
+// {
+// std::tuple<int, std::string> tuple1(42, "bar");
+// // Invokes the first user function on int, std::string.
+// absl::apply(&user_function1, tuple1);
+//
+// std::tuple<std::unique_ptr<Foo>> tuple2(absl::make_unique<Foo>());
+// // Invokes the user function that takes ownership of the unique
+// // pointer.
+// absl::apply(&user_function2, std::move(tuple2));
+//
+// auto foo = absl::make_unique<Foo>();
+// std::tuple<Foo*, int> tuple3(foo.get(), 42);
+// // Invokes the method Bar on foo with one argument, 42.
+// absl::apply(&Foo::Bar, tuple3);
+//
+// std::tuple<int, int> tuple4(8, 9);
+// // Invokes a lambda.
+// absl::apply(user_lambda, tuple4);
+// }
+template <typename Functor, typename Tuple>
+auto apply(Functor&& functor, Tuple&& t)
+ -> decltype(utility_internal::apply_helper(
+ absl::forward<Functor>(functor), absl::forward<Tuple>(t),
+ absl::make_index_sequence<std::tuple_size<
+ typename std::remove_reference<Tuple>::type>::value>{})) {
+ return utility_internal::apply_helper(
+ absl::forward<Functor>(functor), absl::forward<Tuple>(t),
+ absl::make_index_sequence<std::tuple_size<
+ typename std::remove_reference<Tuple>::type>::value>{});
+}
+
+// exchange
+//
+// Replaces the value of `obj` with `new_value` and returns the old value of
+// `obj`. `absl::exchange` is designed to be a drop-in replacement for C++14's
+// `std::exchange`.
+//
+// Example:
+//
+// Foo& operator=(Foo&& other) {
+// ptr1_ = absl::exchange(other.ptr1_, nullptr);
+// int1_ = absl::exchange(other.int1_, -1);
+// return *this;
+// }
+template <typename T, typename U = T>
+T exchange(T& obj, U&& new_value) {
+ T old_value = absl::move(obj);
+ obj = absl::forward<U>(new_value);
+ return old_value;
+}
+
+namespace utility_internal {
+template <typename T, typename Tuple, size_t... I>
+T make_from_tuple_impl(Tuple&& tup, absl::index_sequence<I...>) {
+ return T(std::get<I>(std::forward<Tuple>(tup))...);
+}
+} // namespace utility_internal
+
+// make_from_tuple
+//
+// Given the template parameter type `T` and a tuple of arguments
+// `std::tuple(arg0, arg1, ..., argN)` constructs an object of type `T` as if by
+// calling `T(arg0, arg1, ..., argN)`.
+//
+// Example:
+//
+// std::tuple<const char*, size_t> args("hello world", 5);
+// auto s = absl::make_from_tuple<std::string>(args);
+// assert(s == "hello");
+//
+template <typename T, typename Tuple>
+constexpr T make_from_tuple(Tuple&& tup) {
+ return utility_internal::make_from_tuple_impl<T>(
+ std::forward<Tuple>(tup),
+ absl::make_index_sequence<
+ std::tuple_size<absl::decay_t<Tuple>>::value>{});
+}
+
+} // namespace absl
+
+#endif // ABSL_UTILITY_UTILITY_H_
diff --git a/absl/utility/utility_test.cc b/absl/utility/utility_test.cc
new file mode 100644
index 0000000..f044ad6
--- /dev/null
+++ b/absl/utility/utility_test.cc
@@ -0,0 +1,376 @@
+// Copyright 2017 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/utility/utility.h"
+
+#include <sstream>
+#include <string>
+#include <tuple>
+#include <type_traits>
+#include <vector>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/base/attributes.h"
+#include "absl/memory/memory.h"
+#include "absl/strings/str_cat.h"
+
+namespace {
+
+#ifdef _MSC_VER
+// Warnings for unused variables in this test are false positives. On other
+// platforms, they are suppressed by ABSL_ATTRIBUTE_UNUSED, but that doesn't
+// work on MSVC.
+// Both the unused variables and the name length warnings are due to calls
+// to absl::make_index_sequence with very large values, creating very long type
+// names. The resulting warnings are so long they make build output unreadable.
+#pragma warning( push )
+#pragma warning( disable : 4503 ) // decorated name length exceeded
+#pragma warning( disable : 4101 ) // unreferenced local variable
+#endif // _MSC_VER
+
+using ::testing::ElementsAre;
+using ::testing::Pointee;
+using ::testing::StaticAssertTypeEq;
+
+TEST(IntegerSequenceTest, ValueType) {
+ StaticAssertTypeEq<int, absl::integer_sequence<int>::value_type>();
+ StaticAssertTypeEq<char, absl::integer_sequence<char>::value_type>();
+}
+
+TEST(IntegerSequenceTest, Size) {
+ EXPECT_EQ(0, (absl::integer_sequence<int>::size()));
+ EXPECT_EQ(1, (absl::integer_sequence<int, 0>::size()));
+ EXPECT_EQ(1, (absl::integer_sequence<int, 1>::size()));
+ EXPECT_EQ(2, (absl::integer_sequence<int, 1, 2>::size()));
+ EXPECT_EQ(3, (absl::integer_sequence<int, 0, 1, 2>::size()));
+ EXPECT_EQ(3, (absl::integer_sequence<int, -123, 123, 456>::size()));
+ constexpr size_t sz = absl::integer_sequence<int, 0, 1>::size();
+ EXPECT_EQ(2, sz);
+}
+
+TEST(IntegerSequenceTest, MakeIndexSequence) {
+ StaticAssertTypeEq<absl::index_sequence<>, absl::make_index_sequence<0>>();
+ StaticAssertTypeEq<absl::index_sequence<0>, absl::make_index_sequence<1>>();
+ StaticAssertTypeEq<absl::index_sequence<0, 1>,
+ absl::make_index_sequence<2>>();
+ StaticAssertTypeEq<absl::index_sequence<0, 1, 2>,
+ absl::make_index_sequence<3>>();
+}
+
+TEST(IntegerSequenceTest, MakeIntegerSequence) {
+ StaticAssertTypeEq<absl::integer_sequence<int>,
+ absl::make_integer_sequence<int, 0>>();
+ StaticAssertTypeEq<absl::integer_sequence<int, 0>,
+ absl::make_integer_sequence<int, 1>>();
+ StaticAssertTypeEq<absl::integer_sequence<int, 0, 1>,
+ absl::make_integer_sequence<int, 2>>();
+ StaticAssertTypeEq<absl::integer_sequence<int, 0, 1, 2>,
+ absl::make_integer_sequence<int, 3>>();
+}
+
+template <typename... Ts>
+class Counter {};
+
+template <size_t... Is>
+void CountAll(absl::index_sequence<Is...>) {
+ // We only need an alias here, but instantiate a variable to silence warnings
+ // for unused typedefs in some compilers.
+ ABSL_ATTRIBUTE_UNUSED Counter<absl::make_index_sequence<Is>...> seq;
+}
+
+// This test verifies that absl::make_index_sequence can handle large arguments
+// without blowing up template instantiation stack, going OOM or taking forever
+// to compile (there is hard 15 minutes limit imposed by forge).
+TEST(IntegerSequenceTest, MakeIndexSequencePerformance) {
+ // O(log N) template instantiations.
+ // We only need an alias here, but instantiate a variable to silence warnings
+ // for unused typedefs in some compilers.
+ ABSL_ATTRIBUTE_UNUSED absl::make_index_sequence<(1 << 16) - 1> seq;
+ // O(N) template instantiations.
+ CountAll(absl::make_index_sequence<(1 << 8) - 1>());
+}
+
+template <typename F, typename Tup, size_t... Is>
+auto ApplyFromTupleImpl(F f, const Tup& tup, absl::index_sequence<Is...>)
+ -> decltype(f(std::get<Is>(tup)...)) {
+ return f(std::get<Is>(tup)...);
+}
+
+template <typename Tup>
+using TupIdxSeq = absl::make_index_sequence<std::tuple_size<Tup>::value>;
+
+template <typename F, typename Tup>
+auto ApplyFromTuple(F f, const Tup& tup)
+ -> decltype(ApplyFromTupleImpl(f, tup, TupIdxSeq<Tup>{})) {
+ return ApplyFromTupleImpl(f, tup, TupIdxSeq<Tup>{});
+}
+
+template <typename T>
+std::string Fmt(const T& x) {
+ std::ostringstream os;
+ os << x;
+ return os.str();
+}
+
+struct PoorStrCat {
+ template <typename... Args>
+ std::string operator()(const Args&... args) const {
+ std::string r;
+ for (const auto& e : {Fmt(args)...}) r += e;
+ return r;
+ }
+};
+
+template <typename Tup, size_t... Is>
+std::vector<std::string> TupStringVecImpl(const Tup& tup,
+ absl::index_sequence<Is...>) {
+ return {Fmt(std::get<Is>(tup))...};
+}
+
+template <typename... Ts>
+std::vector<std::string> TupStringVec(const std::tuple<Ts...>& tup) {
+ return TupStringVecImpl(tup, absl::index_sequence_for<Ts...>());
+}
+
+TEST(MakeIndexSequenceTest, ApplyFromTupleExample) {
+ PoorStrCat f{};
+ EXPECT_EQ("12abc3.14", f(12, "abc", 3.14));
+ EXPECT_EQ("12abc3.14", ApplyFromTuple(f, std::make_tuple(12, "abc", 3.14)));
+}
+
+TEST(IndexSequenceForTest, Basic) {
+ StaticAssertTypeEq<absl::index_sequence<>, absl::index_sequence_for<>>();
+ StaticAssertTypeEq<absl::index_sequence<0>, absl::index_sequence_for<int>>();
+ StaticAssertTypeEq<absl::index_sequence<0, 1, 2, 3>,
+ absl::index_sequence_for<int, void, char, int>>();
+}
+
+TEST(IndexSequenceForTest, Example) {
+ EXPECT_THAT(TupStringVec(std::make_tuple(12, "abc", 3.14)),
+ ElementsAre("12", "abc", "3.14"));
+}
+
+int Function(int a, int b) { return a - b; }
+
+int Sink(std::unique_ptr<int> p) { return *p; }
+
+std::unique_ptr<int> Factory(int n) { return absl::make_unique<int>(n); }
+
+void NoOp() {}
+
+struct ConstFunctor {
+ int operator()(int a, int b) const { return a - b; }
+};
+
+struct MutableFunctor {
+ int operator()(int a, int b) { return a - b; }
+};
+
+struct EphemeralFunctor {
+ EphemeralFunctor() {}
+ EphemeralFunctor(const EphemeralFunctor&) {}
+ EphemeralFunctor(EphemeralFunctor&&) {}
+ int operator()(int a, int b) && { return a - b; }
+};
+
+struct OverloadedFunctor {
+ OverloadedFunctor() {}
+ OverloadedFunctor(const OverloadedFunctor&) {}
+ OverloadedFunctor(OverloadedFunctor&&) {}
+ template <typename... Args>
+ std::string operator()(const Args&... args) & {
+ return absl::StrCat("&", args...);
+ }
+ template <typename... Args>
+ std::string operator()(const Args&... args) const& {
+ return absl::StrCat("const&", args...);
+ }
+ template <typename... Args>
+ std::string operator()(const Args&... args) && {
+ return absl::StrCat("&&", args...);
+ }
+};
+
+struct Class {
+ int Method(int a, int b) { return a - b; }
+ int ConstMethod(int a, int b) const { return a - b; }
+
+ int member;
+};
+
+struct FlipFlop {
+ int ConstMethod() const { return member; }
+ FlipFlop operator*() const { return {-member}; }
+
+ int member;
+};
+
+TEST(ApplyTest, Function) {
+ EXPECT_EQ(1, absl::apply(Function, std::make_tuple(3, 2)));
+ EXPECT_EQ(1, absl::apply(&Function, std::make_tuple(3, 2)));
+}
+
+TEST(ApplyTest, NonCopyableArgument) {
+ EXPECT_EQ(42, absl::apply(Sink, std::make_tuple(absl::make_unique<int>(42))));
+}
+
+TEST(ApplyTest, NonCopyableResult) {
+ EXPECT_THAT(absl::apply(Factory, std::make_tuple(42)),
+ ::testing::Pointee(42));
+}
+
+TEST(ApplyTest, VoidResult) { absl::apply(NoOp, std::tuple<>()); }
+
+TEST(ApplyTest, ConstFunctor) {
+ EXPECT_EQ(1, absl::apply(ConstFunctor(), std::make_tuple(3, 2)));
+}
+
+TEST(ApplyTest, MutableFunctor) {
+ MutableFunctor f;
+ EXPECT_EQ(1, absl::apply(f, std::make_tuple(3, 2)));
+ EXPECT_EQ(1, absl::apply(MutableFunctor(), std::make_tuple(3, 2)));
+}
+TEST(ApplyTest, EphemeralFunctor) {
+ EphemeralFunctor f;
+ EXPECT_EQ(1, absl::apply(std::move(f), std::make_tuple(3, 2)));
+ EXPECT_EQ(1, absl::apply(EphemeralFunctor(), std::make_tuple(3, 2)));
+}
+TEST(ApplyTest, OverloadedFunctor) {
+ OverloadedFunctor f;
+ const OverloadedFunctor& cf = f;
+
+ EXPECT_EQ("&", absl::apply(f, std::tuple<>{}));
+ EXPECT_EQ("& 42", absl::apply(f, std::make_tuple(" 42")));
+
+ EXPECT_EQ("const&", absl::apply(cf, std::tuple<>{}));
+ EXPECT_EQ("const& 42", absl::apply(cf, std::make_tuple(" 42")));
+
+ EXPECT_EQ("&&", absl::apply(std::move(f), std::tuple<>{}));
+ OverloadedFunctor f2;
+ EXPECT_EQ("&& 42", absl::apply(std::move(f2), std::make_tuple(" 42")));
+}
+
+TEST(ApplyTest, ReferenceWrapper) {
+ ConstFunctor cf;
+ MutableFunctor mf;
+ EXPECT_EQ(1, absl::apply(std::cref(cf), std::make_tuple(3, 2)));
+ EXPECT_EQ(1, absl::apply(std::ref(cf), std::make_tuple(3, 2)));
+ EXPECT_EQ(1, absl::apply(std::ref(mf), std::make_tuple(3, 2)));
+}
+
+TEST(ApplyTest, MemberFunction) {
+ std::unique_ptr<Class> p(new Class);
+ std::unique_ptr<const Class> cp(new Class);
+ EXPECT_EQ(
+ 1, absl::apply(&Class::Method,
+ std::tuple<std::unique_ptr<Class>&, int, int>(p, 3, 2)));
+ EXPECT_EQ(1, absl::apply(&Class::Method,
+ std::tuple<Class*, int, int>(p.get(), 3, 2)));
+ EXPECT_EQ(
+ 1, absl::apply(&Class::Method, std::tuple<Class&, int, int>(*p, 3, 2)));
+
+ EXPECT_EQ(
+ 1, absl::apply(&Class::ConstMethod,
+ std::tuple<std::unique_ptr<Class>&, int, int>(p, 3, 2)));
+ EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
+ std::tuple<Class*, int, int>(p.get(), 3, 2)));
+ EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
+ std::tuple<Class&, int, int>(*p, 3, 2)));
+
+ EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
+ std::tuple<std::unique_ptr<const Class>&, int, int>(
+ cp, 3, 2)));
+ EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
+ std::tuple<const Class*, int, int>(cp.get(), 3, 2)));
+ EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
+ std::tuple<const Class&, int, int>(*cp, 3, 2)));
+
+ EXPECT_EQ(1, absl::apply(&Class::Method,
+ std::make_tuple(absl::make_unique<Class>(), 3, 2)));
+ EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
+ std::make_tuple(absl::make_unique<Class>(), 3, 2)));
+ EXPECT_EQ(
+ 1, absl::apply(&Class::ConstMethod,
+ std::make_tuple(absl::make_unique<const Class>(), 3, 2)));
+}
+
+TEST(ApplyTest, DataMember) {
+ std::unique_ptr<Class> p(new Class{42});
+ std::unique_ptr<const Class> cp(new Class{42});
+ EXPECT_EQ(
+ 42, absl::apply(&Class::member, std::tuple<std::unique_ptr<Class>&>(p)));
+ EXPECT_EQ(42, absl::apply(&Class::member, std::tuple<Class&>(*p)));
+ EXPECT_EQ(42, absl::apply(&Class::member, std::tuple<Class*>(p.get())));
+
+ absl::apply(&Class::member, std::tuple<std::unique_ptr<Class>&>(p)) = 42;
+ absl::apply(&Class::member, std::tuple<Class*>(p.get())) = 42;
+ absl::apply(&Class::member, std::tuple<Class&>(*p)) = 42;
+
+ EXPECT_EQ(42, absl::apply(&Class::member,
+ std::tuple<std::unique_ptr<const Class>&>(cp)));
+ EXPECT_EQ(42, absl::apply(&Class::member, std::tuple<const Class&>(*cp)));
+ EXPECT_EQ(42,
+ absl::apply(&Class::member, std::tuple<const Class*>(cp.get())));
+}
+
+TEST(ApplyTest, FlipFlop) {
+ FlipFlop obj = {42};
+ // This call could resolve to (obj.*&FlipFlop::ConstMethod)() or
+ // ((*obj).*&FlipFlop::ConstMethod)(). We verify that it's the former.
+ EXPECT_EQ(42, absl::apply(&FlipFlop::ConstMethod, std::make_tuple(obj)));
+ EXPECT_EQ(42, absl::apply(&FlipFlop::member, std::make_tuple(obj)));
+}
+
+TEST(ExchangeTest, MoveOnly) {
+ auto a = Factory(1);
+ EXPECT_EQ(1, *a);
+ auto b = absl::exchange(a, Factory(2));
+ EXPECT_EQ(2, *a);
+ EXPECT_EQ(1, *b);
+}
+
+TEST(MakeFromTupleTest, String) {
+ EXPECT_EQ(
+ absl::make_from_tuple<std::string>(std::make_tuple("hello world", 5)),
+ "hello");
+}
+
+TEST(MakeFromTupleTest, MoveOnlyParameter) {
+ struct S {
+ S(std::unique_ptr<int> n, std::unique_ptr<int> m) : value(*n + *m) {}
+ int value = 0;
+ };
+ auto tup =
+ std::make_tuple(absl::make_unique<int>(3), absl::make_unique<int>(4));
+ auto s = absl::make_from_tuple<S>(std::move(tup));
+ EXPECT_EQ(s.value, 7);
+}
+
+TEST(MakeFromTupleTest, NoParameters) {
+ struct S {
+ S() : value(1) {}
+ int value = 2;
+ };
+ EXPECT_EQ(absl::make_from_tuple<S>(std::make_tuple()).value, 1);
+}
+
+TEST(MakeFromTupleTest, Pair) {
+ EXPECT_EQ(
+ (absl::make_from_tuple<std::pair<bool, int>>(std::make_tuple(true, 17))),
+ std::make_pair(true, 17));
+}
+
+} // namespace
+