Changes imported from Abseil "staging" branch:
- 5e874e644191fbf99f5636d6303de2b28b23392c Adds a absl::apply function, similar to c++17's std::apply. by Abseil Team <absl-team@google.com> - 16373c438d16a09725dace03ab7ba0f7c2337279 Add debugging_internal::StackTraceWorksForTest by Abseil Team <absl-team@google.com> - a623257aaaff8a5fba3377f34f92f319a104e444 Update absl::CondVar documentation in response to GitHub ... by Derek Mauro <dmauro@google.com> - 87d58a25bc4ecd46165dd1c417121c86cbc07be0 Add assert against uint128 negative bit shift undefined b... by Alex Strelnikov <strel@google.com> - af155c0d2a3556b56a9bcd6f9ee7416277185df8 Fix comment typos. by Abseil Team <absl-team@google.com> - 1824ae832eb75d447dea730b5968d952897e135a Rollback of: Add debugging_internal::StackTraceWorksForTest by Abseil Team <absl-team@google.com> - 97318f087ce63dd5acf1e0d3d697cd90a7d6ebfd Add debugging_internal::StackTraceWorksForTest by Abseil Team <absl-team@google.com> - 9dd1d17dca17f0ded3bda336b7521fd57d08a5cc Move log_severity.h out of internal. by Abseil Team <absl-team@google.com> - 2212bb56b1a8365d2303ff0983441298d08444e5 Internal change. by Alex Strelnikov <strel@google.com> GitOrigin-RevId: 5e874e644191fbf99f5636d6303de2b28b23392c Change-Id: Ic270393ac1f15866afb64617d28269cd829030f6
This commit is contained in:
Abseil Team
vslashg
parent
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commit
5a8de8a37e
19 changed files with 326 additions and 58 deletions
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@ -14,6 +14,7 @@ cc_library(
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hdrs = ["utility.h"],
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copts = ABSL_DEFAULT_COPTS,
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deps = [
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"//absl/base:base_internal",
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"//absl/base:config",
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"//absl/meta:type_traits",
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],
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@ -26,6 +27,8 @@ cc_test(
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deps = [
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":utility",
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"//absl/base:core_headers",
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"//absl/memory",
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"//absl/strings",
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"@com_google_googletest//:gtest_main",
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],
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)
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@ -23,6 +23,7 @@
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// * make_integer_sequence<T, N> == std::make_integer_sequence<T, N>
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// * make_index_sequence<N> == std::make_index_sequence<N>
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// * index_sequence_for<Ts...> == std::index_sequence_for<Ts...>
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// * apply<Functor, Tuple> == std::apply<Functor, Tuple>
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//
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// This header file also provides the tag types `in_place_t`, `in_place_type_t`,
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// and `in_place_index_t`, as well as the constant `in_place`, and
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@ -31,34 +32,20 @@
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// References:
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//
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// http://en.cppreference.com/w/cpp/utility/integer_sequence
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// http://en.cppreference.com/w/cpp/utility/apply
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// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3658.html
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//
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//
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// Example:
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// // Unpack a tuple for use as a function call's argument list.
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//
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// template <typename F, typename Tup, size_t... Is>
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// auto Impl(F f, const Tup& tup, absl::index_sequence<Is...>)
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// -> decltype(f(std::get<Is>(tup) ...)) {
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// return f(std::get<Is>(tup) ...);
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// }
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//
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// template <typename Tup>
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// using TupIdxSeq = absl::make_index_sequence<std::tuple_size<Tup>::value>;
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//
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// template <typename F, typename Tup>
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// auto ApplyFromTuple(F f, const Tup& tup)
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// -> decltype(Impl(f, tup, TupIdxSeq<Tup>{})) {
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// return Impl(f, tup, TupIdxSeq<Tup>{});
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// }
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#ifndef ABSL_UTILITY_UTILITY_H_
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#define ABSL_UTILITY_UTILITY_H_
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#include <cstddef>
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#include <cstdlib>
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#include <tuple>
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#include <utility>
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#include "absl/base/config.h"
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#include "absl/base/internal/invoke.h"
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#include "absl/meta/type_traits.h"
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namespace absl {
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@ -214,6 +201,62 @@ constexpr T&& forward(
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return static_cast<T&&>(t);
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}
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namespace utility_internal {
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// Helper method for expanding tuple into a called method.
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template <typename Functor, typename Tuple, std::size_t... Indexes>
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auto apply_helper(Functor&& functor, Tuple&& t, index_sequence<Indexes...>)
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-> decltype(absl::base_internal::Invoke(
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absl::forward<Functor>(functor),
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std::get<Indexes>(absl::forward<Tuple>(t))...)) {
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return absl::base_internal::Invoke(
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absl::forward<Functor>(functor),
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std::get<Indexes>(absl::forward<Tuple>(t))...);
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}
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} // namespace utility_internal
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// apply
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//
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// Invokes a Callable using elements of a tuple as its arguments.
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// Each element of the tuple corresponds to an argument of the call (in order).
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// Both the Callable argument and the tuple argument are perfect-forwarded.
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// For member-function Callables, the first tuple element acts as the `this`
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// pointer. `absl::apply` is designed to be a drop-in replacement for C++17's
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// `std::apply`. Unlike C++17's `std::apply`, this is not currently `constexpr`.
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//
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// Example:
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//
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// class Foo{void Bar(int);};
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// void user_function(int, std::string);
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// void user_function(std::unique_ptr<Foo>);
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//
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// int main()
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// {
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// std::tuple<int, std::string> tuple1(42, "bar");
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// // Invokes the user function overload on int, std::string.
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// absl::apply(&user_function, tuple1);
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//
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// auto foo = absl::make_unique<Foo>();
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// std::tuple<Foo*, int> tuple2(foo.get(), 42);
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// // Invokes the method Bar on foo with one argument 42.
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// absl::apply(&Foo::Bar, foo.get(), 42);
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//
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// std::tuple<std::unique_ptr<Foo>> tuple3(absl::make_unique<Foo>());
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// // Invokes the user function that takes ownership of the unique
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// // pointer.
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// absl::apply(&user_function, std::move(tuple));
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// }
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template <typename Functor, typename Tuple>
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auto apply(Functor&& functor, Tuple&& t)
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-> decltype(utility_internal::apply_helper(
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absl::forward<Functor>(functor), absl::forward<Tuple>(t),
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absl::make_index_sequence<std::tuple_size<
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typename std::remove_reference<Tuple>::type>::value>{})) {
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return utility_internal::apply_helper(
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absl::forward<Functor>(functor), absl::forward<Tuple>(t),
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absl::make_index_sequence<std::tuple_size<
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typename std::remove_reference<Tuple>::type>::value>{});
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}
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} // namespace absl
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#endif // ABSL_UTILITY_UTILITY_H_
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@ -23,6 +23,8 @@
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#include "gmock/gmock.h"
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#include "gtest/gtest.h"
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#include "absl/base/attributes.h"
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#include "absl/memory/memory.h"
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#include "absl/strings/str_cat.h"
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namespace {
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@ -38,8 +40,9 @@ namespace {
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#pragma warning( disable : 4101 ) // unreferenced local variable
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#endif // _MSC_VER
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using testing::StaticAssertTypeEq;
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using testing::ElementsAre;
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using ::testing::ElementsAre;
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using ::testing::Pointee;
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using ::testing::StaticAssertTypeEq;
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TEST(IntegerSequenceTest, ValueType) {
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StaticAssertTypeEq<int, absl::integer_sequence<int>::value_type>();
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@ -159,5 +162,176 @@ TEST(IndexSequenceForTest, Example) {
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ElementsAre("12", "abc", "3.14"));
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}
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int Function(int a, int b) { return a - b; }
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int Sink(std::unique_ptr<int> p) { return *p; }
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std::unique_ptr<int> Factory(int n) { return absl::make_unique<int>(n); }
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void NoOp() {}
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struct ConstFunctor {
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int operator()(int a, int b) const { return a - b; }
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};
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struct MutableFunctor {
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int operator()(int a, int b) { return a - b; }
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};
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struct EphemeralFunctor {
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EphemeralFunctor() {}
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EphemeralFunctor(const EphemeralFunctor&) {}
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EphemeralFunctor(EphemeralFunctor&&) {}
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int operator()(int a, int b) && { return a - b; }
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};
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struct OverloadedFunctor {
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OverloadedFunctor() {}
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OverloadedFunctor(const OverloadedFunctor&) {}
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OverloadedFunctor(OverloadedFunctor&&) {}
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template <typename... Args>
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std::string operator()(const Args&... args) & {
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return absl::StrCat("&", args...);
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}
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template <typename... Args>
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std::string operator()(const Args&... args) const& {
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return absl::StrCat("const&", args...);
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}
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template <typename... Args>
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std::string operator()(const Args&... args) && {
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return absl::StrCat("&&", args...);
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}
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};
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struct Class {
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int Method(int a, int b) { return a - b; }
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int ConstMethod(int a, int b) const { return a - b; }
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int member;
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};
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struct FlipFlop {
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int ConstMethod() const { return member; }
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FlipFlop operator*() const { return {-member}; }
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int member;
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};
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TEST(ApplyTest, Function) {
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EXPECT_EQ(1, absl::apply(Function, std::make_tuple(3, 2)));
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EXPECT_EQ(1, absl::apply(&Function, std::make_tuple(3, 2)));
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}
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TEST(ApplyTest, NonCopyableArgument) {
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EXPECT_EQ(42, absl::apply(Sink, std::make_tuple(absl::make_unique<int>(42))));
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}
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TEST(ApplyTest, NonCopyableResult) {
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EXPECT_THAT(absl::apply(Factory, std::make_tuple(42)),
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::testing::Pointee(42));
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}
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TEST(ApplyTest, VoidResult) { absl::apply(NoOp, std::tuple<>()); }
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TEST(ApplyTest, ConstFunctor) {
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EXPECT_EQ(1, absl::apply(ConstFunctor(), std::make_tuple(3, 2)));
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}
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TEST(ApplyTest, MutableFunctor) {
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MutableFunctor f;
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EXPECT_EQ(1, absl::apply(f, std::make_tuple(3, 2)));
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EXPECT_EQ(1, absl::apply(MutableFunctor(), std::make_tuple(3, 2)));
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}
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TEST(ApplyTest, EphemeralFunctor) {
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EphemeralFunctor f;
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EXPECT_EQ(1, absl::apply(std::move(f), std::make_tuple(3, 2)));
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EXPECT_EQ(1, absl::apply(EphemeralFunctor(), std::make_tuple(3, 2)));
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}
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TEST(ApplyTest, OverloadedFunctor) {
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OverloadedFunctor f;
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const OverloadedFunctor& cf = f;
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EXPECT_EQ("&", absl::apply(f, std::tuple<>{}));
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EXPECT_EQ("& 42", absl::apply(f, std::make_tuple(" 42")));
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EXPECT_EQ("const&", absl::apply(cf, std::tuple<>{}));
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EXPECT_EQ("const& 42", absl::apply(cf, std::make_tuple(" 42")));
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EXPECT_EQ("&&", absl::apply(std::move(f), std::tuple<>{}));
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OverloadedFunctor f2;
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EXPECT_EQ("&& 42", absl::apply(std::move(f2), std::make_tuple(" 42")));
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}
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TEST(ApplyTest, ReferenceWrapper) {
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ConstFunctor cf;
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MutableFunctor mf;
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EXPECT_EQ(1, absl::apply(std::cref(cf), std::make_tuple(3, 2)));
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EXPECT_EQ(1, absl::apply(std::ref(cf), std::make_tuple(3, 2)));
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EXPECT_EQ(1, absl::apply(std::ref(mf), std::make_tuple(3, 2)));
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}
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TEST(ApplyTest, MemberFunction) {
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std::unique_ptr<Class> p(new Class);
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std::unique_ptr<const Class> cp(new Class);
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EXPECT_EQ(
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1, absl::apply(&Class::Method,
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std::tuple<std::unique_ptr<Class>&, int, int>(p, 3, 2)));
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EXPECT_EQ(1, absl::apply(&Class::Method,
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std::tuple<Class*, int, int>(p.get(), 3, 2)));
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EXPECT_EQ(
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1, absl::apply(&Class::Method, std::tuple<Class&, int, int>(*p, 3, 2)));
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EXPECT_EQ(
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1, absl::apply(&Class::ConstMethod,
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std::tuple<std::unique_ptr<Class>&, int, int>(p, 3, 2)));
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EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
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std::tuple<Class*, int, int>(p.get(), 3, 2)));
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EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
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std::tuple<Class&, int, int>(*p, 3, 2)));
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EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
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std::tuple<std::unique_ptr<const Class>&, int, int>(
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cp, 3, 2)));
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EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
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std::tuple<const Class*, int, int>(cp.get(), 3, 2)));
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EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
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std::tuple<const Class&, int, int>(*cp, 3, 2)));
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EXPECT_EQ(1, absl::apply(&Class::Method,
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std::make_tuple(absl::make_unique<Class>(), 3, 2)));
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EXPECT_EQ(1, absl::apply(&Class::ConstMethod,
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std::make_tuple(absl::make_unique<Class>(), 3, 2)));
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EXPECT_EQ(
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1, absl::apply(&Class::ConstMethod,
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std::make_tuple(absl::make_unique<const Class>(), 3, 2)));
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}
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TEST(ApplyTest, DataMember) {
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std::unique_ptr<Class> p(new Class{42});
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std::unique_ptr<const Class> cp(new Class{42});
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EXPECT_EQ(
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42, absl::apply(&Class::member, std::tuple<std::unique_ptr<Class>&>(p)));
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EXPECT_EQ(42, absl::apply(&Class::member, std::tuple<Class&>(*p)));
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EXPECT_EQ(42, absl::apply(&Class::member, std::tuple<Class*>(p.get())));
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absl::apply(&Class::member, std::tuple<std::unique_ptr<Class>&>(p)) = 42;
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absl::apply(&Class::member, std::tuple<Class*>(p.get())) = 42;
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absl::apply(&Class::member, std::tuple<Class&>(*p)) = 42;
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EXPECT_EQ(42, absl::apply(&Class::member,
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std::tuple<std::unique_ptr<const Class>&>(cp)));
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EXPECT_EQ(42, absl::apply(&Class::member, std::tuple<const Class&>(*cp)));
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EXPECT_EQ(42,
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absl::apply(&Class::member, std::tuple<const Class*>(cp.get())));
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}
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TEST(ApplyTest, FlipFlop) {
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FlipFlop obj = {42};
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// This call could resolve to (obj.*&FlipFlop::ConstMethod)() or
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// ((*obj).*&FlipFlop::ConstMethod)(). We verify that it's the former.
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EXPECT_EQ(42, absl::apply(&FlipFlop::ConstMethod, std::make_tuple(obj)));
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EXPECT_EQ(42, absl::apply(&FlipFlop::member, std::make_tuple(obj)));
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}
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} // namespace
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