// 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
