From 5a8de8a37e3e282d22f69ca67b4aba8e4cca63ae Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Wed, 17 Jan 2018 09:53:47 -0800 Subject: Changes imported from Abseil "staging" branch: - 5e874e644191fbf99f5636d6303de2b28b23392c Adds a absl::apply function, similar to c++17's std::apply. by Abseil Team - 16373c438d16a09725dace03ab7ba0f7c2337279 Add debugging_internal::StackTraceWorksForTest by Abseil Team - a623257aaaff8a5fba3377f34f92f319a104e444 Update absl::CondVar documentation in response to GitHub ... by Derek Mauro - 87d58a25bc4ecd46165dd1c417121c86cbc07be0 Add assert against uint128 negative bit shift undefined b... by Alex Strelnikov - af155c0d2a3556b56a9bcd6f9ee7416277185df8 Fix comment typos. by Abseil Team - 1824ae832eb75d447dea730b5968d952897e135a Rollback of: Add debugging_internal::StackTraceWorksForTest by Abseil Team - 97318f087ce63dd5acf1e0d3d697cd90a7d6ebfd Add debugging_internal::StackTraceWorksForTest by Abseil Team - 9dd1d17dca17f0ded3bda336b7521fd57d08a5cc Move log_severity.h out of internal. by Abseil Team - 2212bb56b1a8365d2303ff0983441298d08444e5 Internal change. by Alex Strelnikov GitOrigin-RevId: 5e874e644191fbf99f5636d6303de2b28b23392c Change-Id: Ic270393ac1f15866afb64617d28269cd829030f6 --- absl/utility/BUILD.bazel | 3 + absl/utility/utility.h | 79 ++++++++++++++----- absl/utility/utility_test.cc | 178 ++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 240 insertions(+), 20 deletions(-) (limited to 'absl/utility') diff --git a/absl/utility/BUILD.bazel b/absl/utility/BUILD.bazel index 396b05f..6298462 100644 --- a/absl/utility/BUILD.bazel +++ b/absl/utility/BUILD.bazel @@ -14,6 +14,7 @@ cc_library( hdrs = ["utility.h"], copts = ABSL_DEFAULT_COPTS, deps = [ + "//absl/base:base_internal", "//absl/base:config", "//absl/meta:type_traits", ], @@ -26,6 +27,8 @@ cc_test( deps = [ ":utility", "//absl/base:core_headers", + "//absl/memory", + "//absl/strings", "@com_google_googletest//:gtest_main", ], ) diff --git a/absl/utility/utility.h b/absl/utility/utility.h index 732cd4c..d37f4c3 100644 --- a/absl/utility/utility.h +++ b/absl/utility/utility.h @@ -23,6 +23,7 @@ // * make_integer_sequence == std::make_integer_sequence // * make_index_sequence == std::make_index_sequence // * index_sequence_for == std::index_sequence_for +// * apply == std::apply // // 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 @@ -31,34 +32,20 @@ // References: // // http://en.cppreference.com/w/cpp/utility/integer_sequence +// http://en.cppreference.com/w/cpp/utility/apply // http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3658.html // -// -// Example: -// // Unpack a tuple for use as a function call's argument list. -// -// template -// auto Impl(F f, const Tup& tup, absl::index_sequence) -// -> decltype(f(std::get(tup) ...)) { -// return f(std::get(tup) ...); -// } -// -// template -// using TupIdxSeq = absl::make_index_sequence::value>; -// -// template -// auto ApplyFromTuple(F f, const Tup& tup) -// -> decltype(Impl(f, tup, TupIdxSeq{})) { -// return Impl(f, tup, TupIdxSeq{}); -// } + #ifndef ABSL_UTILITY_UTILITY_H_ #define ABSL_UTILITY_UTILITY_H_ #include #include +#include #include #include "absl/base/config.h" +#include "absl/base/internal/invoke.h" #include "absl/meta/type_traits.h" namespace absl { @@ -214,6 +201,62 @@ constexpr T&& forward( return static_cast(t); } +namespace utility_internal { +// Helper method for expanding tuple into a called method. +template +auto apply_helper(Functor&& functor, Tuple&& t, index_sequence) + -> decltype(absl::base_internal::Invoke( + absl::forward(functor), + std::get(absl::forward(t))...)) { + return absl::base_internal::Invoke( + absl::forward(functor), + std::get(absl::forward(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{void Bar(int);}; +// void user_function(int, std::string); +// void user_function(std::unique_ptr); +// +// int main() +// { +// std::tuple tuple1(42, "bar"); +// // Invokes the user function overload on int, std::string. +// absl::apply(&user_function, tuple1); +// +// auto foo = absl::make_unique(); +// std::tuple tuple2(foo.get(), 42); +// // Invokes the method Bar on foo with one argument 42. +// absl::apply(&Foo::Bar, foo.get(), 42); +// +// std::tuple> tuple3(absl::make_unique()); +// // Invokes the user function that takes ownership of the unique +// // pointer. +// absl::apply(&user_function, std::move(tuple)); +// } +template +auto apply(Functor&& functor, Tuple&& t) + -> decltype(utility_internal::apply_helper( + absl::forward(functor), absl::forward(t), + absl::make_index_sequence::type>::value>{})) { + return utility_internal::apply_helper( + absl::forward(functor), absl::forward(t), + absl::make_index_sequence::type>::value>{}); +} } // namespace absl #endif // ABSL_UTILITY_UTILITY_H_ diff --git a/absl/utility/utility_test.cc b/absl/utility/utility_test.cc index 62cb46f..342165e 100644 --- a/absl/utility/utility_test.cc +++ b/absl/utility/utility_test.cc @@ -23,6 +23,8 @@ #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 { @@ -38,8 +40,9 @@ namespace { #pragma warning( disable : 4101 ) // unreferenced local variable #endif // _MSC_VER -using testing::StaticAssertTypeEq; -using testing::ElementsAre; +using ::testing::ElementsAre; +using ::testing::Pointee; +using ::testing::StaticAssertTypeEq; TEST(IntegerSequenceTest, ValueType) { StaticAssertTypeEq::value_type>(); @@ -159,5 +162,176 @@ TEST(IndexSequenceForTest, Example) { ElementsAre("12", "abc", "3.14")); } +int Function(int a, int b) { return a - b; } + +int Sink(std::unique_ptr p) { return *p; } + +std::unique_ptr Factory(int n) { return absl::make_unique(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 + std::string operator()(const Args&... args) & { + return absl::StrCat("&", args...); + } + template + std::string operator()(const Args&... args) const& { + return absl::StrCat("const&", args...); + } + template + 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(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 p(new Class); + std::unique_ptr cp(new Class); + EXPECT_EQ( + 1, absl::apply(&Class::Method, + std::tuple&, int, int>(p, 3, 2))); + EXPECT_EQ(1, absl::apply(&Class::Method, + std::tuple(p.get(), 3, 2))); + EXPECT_EQ( + 1, absl::apply(&Class::Method, std::tuple(*p, 3, 2))); + + EXPECT_EQ( + 1, absl::apply(&Class::ConstMethod, + std::tuple&, int, int>(p, 3, 2))); + EXPECT_EQ(1, absl::apply(&Class::ConstMethod, + std::tuple(p.get(), 3, 2))); + EXPECT_EQ(1, absl::apply(&Class::ConstMethod, + std::tuple(*p, 3, 2))); + + EXPECT_EQ(1, absl::apply(&Class::ConstMethod, + std::tuple&, int, int>( + cp, 3, 2))); + EXPECT_EQ(1, absl::apply(&Class::ConstMethod, + std::tuple(cp.get(), 3, 2))); + EXPECT_EQ(1, absl::apply(&Class::ConstMethod, + std::tuple(*cp, 3, 2))); + + EXPECT_EQ(1, absl::apply(&Class::Method, + std::make_tuple(absl::make_unique(), 3, 2))); + EXPECT_EQ(1, absl::apply(&Class::ConstMethod, + std::make_tuple(absl::make_unique(), 3, 2))); + EXPECT_EQ( + 1, absl::apply(&Class::ConstMethod, + std::make_tuple(absl::make_unique(), 3, 2))); +} + +TEST(ApplyTest, DataMember) { + std::unique_ptr p(new Class{42}); + std::unique_ptr cp(new Class{42}); + EXPECT_EQ( + 42, absl::apply(&Class::member, std::tuple&>(p))); + EXPECT_EQ(42, absl::apply(&Class::member, std::tuple(*p))); + EXPECT_EQ(42, absl::apply(&Class::member, std::tuple(p.get()))); + + absl::apply(&Class::member, std::tuple&>(p)) = 42; + absl::apply(&Class::member, std::tuple(p.get())) = 42; + absl::apply(&Class::member, std::tuple(*p)) = 42; + + EXPECT_EQ(42, absl::apply(&Class::member, + std::tuple&>(cp))); + EXPECT_EQ(42, absl::apply(&Class::member, std::tuple(*cp))); + EXPECT_EQ(42, + absl::apply(&Class::member, std::tuple(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))); +} + } // namespace -- cgit v1.2.3