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// 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
//
// http://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/base/internal/invoke.h"
#include <functional>
#include <memory>
#include <string>
#include <utility>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/memory/memory.h"
#include "absl/strings/str_cat.h"
namespace absl {
inline namespace lts_2018_06_20 {
namespace base_internal {
namespace {
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 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 {
int operator()(int a, int b) && { return a - b; }
};
struct OverloadedFunctor {
template <typename... Args>
std::string operator()(const Args&... args) & {
return StrCat("&", args...);
}
template <typename... Args>
std::string operator()(const Args&... args) const& {
return StrCat("const&", args...);
}
template <typename... Args>
std::string operator()(const Args&... args) && {
return 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;
};
// CallMaybeWithArg(f) resolves either to Invoke(f) or Invoke(f, 42), depending
// on which one is valid.
template <typename F>
decltype(Invoke(std::declval<const F&>())) CallMaybeWithArg(const F& f) {
return Invoke(f);
}
template <typename F>
decltype(Invoke(std::declval<const F&>(), 42)) CallMaybeWithArg(const F& f) {
return Invoke(f, 42);
}
TEST(InvokeTest, Function) {
EXPECT_EQ(1, Invoke(Function, 3, 2));
EXPECT_EQ(1, Invoke(&Function, 3, 2));
}
TEST(InvokeTest, NonCopyableArgument) {
EXPECT_EQ(42, Invoke(Sink, make_unique<int>(42)));
}
TEST(InvokeTest, NonCopyableResult) {
EXPECT_THAT(Invoke(Factory, 42), ::testing::Pointee(42));
}
TEST(InvokeTest, VoidResult) {
Invoke(NoOp);
}
TEST(InvokeTest, ConstFunctor) {
EXPECT_EQ(1, Invoke(ConstFunctor(), 3, 2));
}
TEST(InvokeTest, MutableFunctor) {
MutableFunctor f;
EXPECT_EQ(1, Invoke(f, 3, 2));
EXPECT_EQ(1, Invoke(MutableFunctor(), 3, 2));
}
TEST(InvokeTest, EphemeralFunctor) {
EphemeralFunctor f;
EXPECT_EQ(1, Invoke(std::move(f), 3, 2));
EXPECT_EQ(1, Invoke(EphemeralFunctor(), 3, 2));
}
TEST(InvokeTest, OverloadedFunctor) {
OverloadedFunctor f;
const OverloadedFunctor& cf = f;
EXPECT_EQ("&", Invoke(f));
EXPECT_EQ("& 42", Invoke(f, " 42"));
EXPECT_EQ("const&", Invoke(cf));
EXPECT_EQ("const& 42", Invoke(cf, " 42"));
EXPECT_EQ("&&", Invoke(std::move(f)));
EXPECT_EQ("&& 42", Invoke(std::move(f), " 42"));
}
TEST(InvokeTest, ReferenceWrapper) {
ConstFunctor cf;
MutableFunctor mf;
EXPECT_EQ(1, Invoke(std::cref(cf), 3, 2));
EXPECT_EQ(1, Invoke(std::ref(cf), 3, 2));
EXPECT_EQ(1, Invoke(std::ref(mf), 3, 2));
}
TEST(InvokeTest, MemberFunction) {
std::unique_ptr<Class> p(new Class);
std::unique_ptr<const Class> cp(new Class);
EXPECT_EQ(1, Invoke(&Class::Method, p, 3, 2));
EXPECT_EQ(1, Invoke(&Class::Method, p.get(), 3, 2));
EXPECT_EQ(1, Invoke(&Class::ConstMethod, p, 3, 2));
EXPECT_EQ(1, Invoke(&Class::ConstMethod, p.get(), 3, 2));
EXPECT_EQ(1, Invoke(&Class::ConstMethod, *p, 3, 2));
EXPECT_EQ(1, Invoke(&Class::ConstMethod, cp, 3, 2));
EXPECT_EQ(1, Invoke(&Class::ConstMethod, cp.get(), 3, 2));
EXPECT_EQ(1, Invoke(&Class::ConstMethod, *cp, 3, 2));
EXPECT_EQ(1, Invoke(&Class::Method, make_unique<Class>(), 3, 2));
EXPECT_EQ(1, Invoke(&Class::ConstMethod, make_unique<Class>(), 3, 2));
EXPECT_EQ(1, Invoke(&Class::ConstMethod, make_unique<const Class>(), 3, 2));
}
TEST(InvokeTest, DataMember) {
std::unique_ptr<Class> p(new Class{42});
std::unique_ptr<const Class> cp(new Class{42});
EXPECT_EQ(42, Invoke(&Class::member, p));
EXPECT_EQ(42, Invoke(&Class::member, *p));
EXPECT_EQ(42, Invoke(&Class::member, p.get()));
Invoke(&Class::member, p) = 42;
Invoke(&Class::member, p.get()) = 42;
EXPECT_EQ(42, Invoke(&Class::member, cp));
EXPECT_EQ(42, Invoke(&Class::member, *cp));
EXPECT_EQ(42, Invoke(&Class::member, cp.get()));
}
TEST(InvokeTest, 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, Invoke(&FlipFlop::ConstMethod, obj));
EXPECT_EQ(42, Invoke(&FlipFlop::member, obj));
}
TEST(InvokeTest, SfinaeFriendly) {
CallMaybeWithArg(NoOp);
EXPECT_THAT(CallMaybeWithArg(Factory), ::testing::Pointee(42));
}
} // namespace
} // namespace base_internal
} // inline namespace lts_2018_06_20
} // namespace absl
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