// Copyright 2022 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 <memory>
#include <sstream>
#include <string>
#include <tuple>
#include <type_traits>
#include <utility>
#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 {
using ::testing::ElementsAre;
using ::testing::Pointee;
using ::testing::StaticAssertTypeEq;
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)), 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(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
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