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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
//
//
// 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 {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
namespace {
int Function(int a, int b) { return a - b; }
void VoidFunction(int& a, int& b) {
a += b;
b = a - b;
a -= b;
}
int ZeroArgFunction() { return -1937; }
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 RefMethod(int a, int b) & { return a - b; }
int RefRefMethod(int a, int b) && { return a - b; }
int NoExceptMethod(int a, int b) noexcept { return a - b; }
int VolatileMethod(int a, int b) volatile { 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(base_internal::invoke(std::declval<const F&>())) CallMaybeWithArg(
const F& f) {
return base_internal::invoke(f);
}
template <typename F>
decltype(base_internal::invoke(std::declval<const F&>(), 42)) CallMaybeWithArg(
const F& f) {
return base_internal::invoke(f, 42);
}
TEST(InvokeTest, Function) {
EXPECT_EQ(1, base_internal::invoke(Function, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Function, 3, 2));
}
TEST(InvokeTest, NonCopyableArgument) {
EXPECT_EQ(42, base_internal::invoke(Sink, make_unique<int>(42)));
}
TEST(InvokeTest, NonCopyableResult) {
EXPECT_THAT(base_internal::invoke(Factory, 42), ::testing::Pointee(42));
}
TEST(InvokeTest, VoidResult) { base_internal::invoke(NoOp); }
TEST(InvokeTest, ConstFunctor) {
EXPECT_EQ(1, base_internal::invoke(ConstFunctor(), 3, 2));
}
TEST(InvokeTest, MutableFunctor) {
MutableFunctor f;
EXPECT_EQ(1, base_internal::invoke(f, 3, 2));
EXPECT_EQ(1, base_internal::invoke(MutableFunctor(), 3, 2));
}
TEST(InvokeTest, EphemeralFunctor) {
EphemeralFunctor f;
EXPECT_EQ(1, base_internal::invoke(std::move(f), 3, 2));
EXPECT_EQ(1, base_internal::invoke(EphemeralFunctor(), 3, 2));
}
TEST(InvokeTest, OverloadedFunctor) {
OverloadedFunctor f;
const OverloadedFunctor& cf = f;
EXPECT_EQ("&", base_internal::invoke(f));
EXPECT_EQ("& 42", base_internal::invoke(f, " 42"));
EXPECT_EQ("const&", base_internal::invoke(cf));
EXPECT_EQ("const& 42", base_internal::invoke(cf, " 42"));
EXPECT_EQ("&&", base_internal::invoke(std::move(f)));
OverloadedFunctor f2;
EXPECT_EQ("&& 42", base_internal::invoke(std::move(f2), " 42"));
}
TEST(InvokeTest, ReferenceWrapper) {
ConstFunctor cf;
MutableFunctor mf;
EXPECT_EQ(1, base_internal::invoke(std::cref(cf), 3, 2));
EXPECT_EQ(1, base_internal::invoke(std::ref(cf), 3, 2));
EXPECT_EQ(1, base_internal::invoke(std::ref(mf), 3, 2));
}
TEST(InvokeTest, MemberFunction) {
std::unique_ptr<Class> p(new Class);
std::unique_ptr<const Class> cp(new Class);
std::unique_ptr<volatile Class> vp(new Class);
EXPECT_EQ(1, base_internal::invoke(&Class::Method, p, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::Method, p.get(), 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::Method, *p, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::RefMethod, p, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::RefMethod, p.get(), 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::RefMethod, *p, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::RefRefMethod, std::move(*p), 3,
2)); // NOLINT
EXPECT_EQ(1, base_internal::invoke(&Class::NoExceptMethod, p, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::NoExceptMethod, p.get(), 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::NoExceptMethod, *p, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::ConstMethod, p, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::ConstMethod, p.get(), 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::ConstMethod, *p, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::ConstMethod, cp, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::ConstMethod, cp.get(), 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::ConstMethod, *cp, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::VolatileMethod, p, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::VolatileMethod, p.get(), 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::VolatileMethod, *p, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::VolatileMethod, vp, 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::VolatileMethod, vp.get(), 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::VolatileMethod, *vp, 3, 2));
EXPECT_EQ(1,
base_internal::invoke(&Class::Method, make_unique<Class>(), 3, 2));
EXPECT_EQ(1, base_internal::invoke(&Class::ConstMethod, make_unique<Class>(),
3, 2));
EXPECT_EQ(1, base_internal::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, base_internal::invoke(&Class::member, p));
EXPECT_EQ(42, base_internal::invoke(&Class::member, *p));
EXPECT_EQ(42, base_internal::invoke(&Class::member, p.get()));
base_internal::invoke(&Class::member, p) = 42;
base_internal::invoke(&Class::member, p.get()) = 42;
EXPECT_EQ(42, base_internal::invoke(&Class::member, cp));
EXPECT_EQ(42, base_internal::invoke(&Class::member, *cp));
EXPECT_EQ(42, base_internal::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, base_internal::invoke(&FlipFlop::ConstMethod, obj));
EXPECT_EQ(42, base_internal::invoke(&FlipFlop::member, obj));
}
TEST(InvokeTest, SfinaeFriendly) {
CallMaybeWithArg(NoOp);
EXPECT_THAT(CallMaybeWithArg(Factory), ::testing::Pointee(42));
}
TEST(IsInvocableRTest, CallableExactMatch) {
static_assert(
base_internal::is_invocable_r<int, decltype(Function), int, int>::value,
"Should be true for exact match of types on a free function");
}
TEST(IsInvocableRTest, CallableArgumentConversionMatch) {
static_assert(
base_internal::is_invocable_r<int, decltype(Function), char, int>::value,
"Should be true for convertible argument type");
}
TEST(IsInvocableRTest, CallableReturnConversionMatch) {
static_assert(base_internal::is_invocable_r<double, decltype(Function), int,
int>::value,
"Should be true for convertible return type");
}
TEST(IsInvocableRTest, CallableReturnVoid) {
static_assert(base_internal::is_invocable_r<void, decltype(VoidFunction),
int&, int&>::value,
"Should be true for void expected and actual return types");
static_assert(
base_internal::is_invocable_r<void, decltype(Function), int, int>::value,
"Should be true for void expected and non-void actual return types");
}
TEST(IsInvocableRTest, CallableRefQualifierMismatch) {
static_assert(!base_internal::is_invocable_r<void, decltype(VoidFunction),
int&, const int&>::value,
"Should be false for reference constness mismatch");
static_assert(!base_internal::is_invocable_r<void, decltype(VoidFunction),
int&&, int&>::value,
"Should be false for reference value category mismatch");
}
TEST(IsInvocableRTest, CallableArgumentTypeMismatch) {
static_assert(!base_internal::is_invocable_r<int, decltype(Function),
std::string, int>::value,
"Should be false for argument type mismatch");
}
TEST(IsInvocableRTest, CallableReturnTypeMismatch) {
static_assert(!base_internal::is_invocable_r<std::string, decltype(Function),
int, int>::value,
"Should be false for return type mismatch");
}
TEST(IsInvocableRTest, CallableTooFewArgs) {
static_assert(
!base_internal::is_invocable_r<int, decltype(Function), int>::value,
"Should be false for too few arguments");
}
TEST(IsInvocableRTest, CallableTooManyArgs) {
static_assert(!base_internal::is_invocable_r<int, decltype(Function), int,
int, int>::value,
"Should be false for too many arguments");
}
TEST(IsInvocableRTest, MemberFunctionAndReference) {
static_assert(base_internal::is_invocable_r<int, decltype(&Class::Method),
Class&, int, int>::value,
"Should be true for exact match of types on a member function "
"and class reference");
}
TEST(IsInvocableRTest, MemberFunctionAndPointer) {
static_assert(base_internal::is_invocable_r<int, decltype(&Class::Method),
Class*, int, int>::value,
"Should be true for exact match of types on a member function "
"and class pointer");
}
TEST(IsInvocableRTest, DataMemberAndReference) {
static_assert(base_internal::is_invocable_r<int, decltype(&Class::member),
Class&>::value,
"Should be true for exact match of types on a data member and "
"class reference");
}
TEST(IsInvocableRTest, DataMemberAndPointer) {
static_assert(base_internal::is_invocable_r<int, decltype(&Class::member),
Class*>::value,
"Should be true for exact match of types on a data member and "
"class pointer");
}
TEST(IsInvocableRTest, CallableZeroArgs) {
static_assert(
base_internal::is_invocable_r<int, decltype(ZeroArgFunction)>::value,
"Should be true for exact match for a zero-arg free function");
}
} // namespace
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl