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Diffstat (limited to 'third_party/abseil_cpp/absl/functional/bind_front_test.cc')
-rw-r--r-- | third_party/abseil_cpp/absl/functional/bind_front_test.cc | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/third_party/abseil_cpp/absl/functional/bind_front_test.cc b/third_party/abseil_cpp/absl/functional/bind_front_test.cc new file mode 100644 index 000000000000..4801a81caf0d --- /dev/null +++ b/third_party/abseil_cpp/absl/functional/bind_front_test.cc @@ -0,0 +1,231 @@ +// Copyright 2018 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/functional/bind_front.h" + +#include <stddef.h> + +#include <functional> +#include <memory> +#include <string> + +#include "gmock/gmock.h" +#include "gtest/gtest.h" +#include "absl/memory/memory.h" + +namespace { + +char CharAt(const char* s, size_t index) { return s[index]; } + +TEST(BindTest, Basics) { + EXPECT_EQ('C', absl::bind_front(CharAt)("ABC", 2)); + EXPECT_EQ('C', absl::bind_front(CharAt, "ABC")(2)); + EXPECT_EQ('C', absl::bind_front(CharAt, "ABC", 2)()); +} + +TEST(BindTest, Lambda) { + auto lambda = [](int x, int y, int z) { return x + y + z; }; + EXPECT_EQ(6, absl::bind_front(lambda)(1, 2, 3)); + EXPECT_EQ(6, absl::bind_front(lambda, 1)(2, 3)); + EXPECT_EQ(6, absl::bind_front(lambda, 1, 2)(3)); + EXPECT_EQ(6, absl::bind_front(lambda, 1, 2, 3)()); +} + +struct Functor { + std::string operator()() & { return "&"; } + std::string operator()() const& { return "const&"; } + std::string operator()() && { return "&&"; } + std::string operator()() const&& { return "const&&"; } +}; + +TEST(BindTest, PerfectForwardingOfBoundArgs) { + auto f = absl::bind_front(Functor()); + const auto& cf = f; + EXPECT_EQ("&", f()); + EXPECT_EQ("const&", cf()); + EXPECT_EQ("&&", std::move(f)()); + EXPECT_EQ("const&&", std::move(cf)()); +} + +struct ArgDescribe { + std::string operator()(int&) const { return "&"; } // NOLINT + std::string operator()(const int&) const { return "const&"; } // NOLINT + std::string operator()(int&&) const { return "&&"; } + std::string operator()(const int&&) const { return "const&&"; } +}; + +TEST(BindTest, PerfectForwardingOfFreeArgs) { + ArgDescribe f; + int i; + EXPECT_EQ("&", absl::bind_front(f)(static_cast<int&>(i))); + EXPECT_EQ("const&", absl::bind_front(f)(static_cast<const int&>(i))); + EXPECT_EQ("&&", absl::bind_front(f)(static_cast<int&&>(i))); + EXPECT_EQ("const&&", absl::bind_front(f)(static_cast<const int&&>(i))); +} + +struct NonCopyableFunctor { + NonCopyableFunctor() = default; + NonCopyableFunctor(const NonCopyableFunctor&) = delete; + NonCopyableFunctor& operator=(const NonCopyableFunctor&) = delete; + const NonCopyableFunctor* operator()() const { return this; } +}; + +TEST(BindTest, RefToFunctor) { + // It won't copy/move the functor and use the original object. + NonCopyableFunctor ncf; + auto bound_ncf = absl::bind_front(std::ref(ncf)); + auto bound_ncf_copy = bound_ncf; + EXPECT_EQ(&ncf, bound_ncf_copy()); +} + +struct Struct { + std::string value; +}; + +TEST(BindTest, StoreByCopy) { + Struct s = {"hello"}; + auto f = absl::bind_front(&Struct::value, s); + auto g = f; + EXPECT_EQ("hello", f()); + EXPECT_EQ("hello", g()); + EXPECT_NE(&s.value, &f()); + EXPECT_NE(&s.value, &g()); + EXPECT_NE(&g(), &f()); +} + +struct NonCopyable { + explicit NonCopyable(const std::string& s) : value(s) {} + NonCopyable(const NonCopyable&) = delete; + NonCopyable& operator=(const NonCopyable&) = delete; + + std::string value; +}; + +const std::string& GetNonCopyableValue(const NonCopyable& n) { return n.value; } + +TEST(BindTest, StoreByRef) { + NonCopyable s("hello"); + auto f = absl::bind_front(&GetNonCopyableValue, std::ref(s)); + EXPECT_EQ("hello", f()); + EXPECT_EQ(&s.value, &f()); + auto g = std::move(f); // NOLINT + EXPECT_EQ("hello", g()); + EXPECT_EQ(&s.value, &g()); + s.value = "goodbye"; + EXPECT_EQ("goodbye", g()); +} + +TEST(BindTest, StoreByCRef) { + NonCopyable s("hello"); + auto f = absl::bind_front(&GetNonCopyableValue, std::cref(s)); + EXPECT_EQ("hello", f()); + EXPECT_EQ(&s.value, &f()); + auto g = std::move(f); // NOLINT + EXPECT_EQ("hello", g()); + EXPECT_EQ(&s.value, &g()); + s.value = "goodbye"; + EXPECT_EQ("goodbye", g()); +} + +const std::string& GetNonCopyableValueByWrapper( + std::reference_wrapper<NonCopyable> n) { + return n.get().value; +} + +TEST(BindTest, StoreByRefInvokeByWrapper) { + NonCopyable s("hello"); + auto f = absl::bind_front(GetNonCopyableValueByWrapper, std::ref(s)); + EXPECT_EQ("hello", f()); + EXPECT_EQ(&s.value, &f()); + auto g = std::move(f); + EXPECT_EQ("hello", g()); + EXPECT_EQ(&s.value, &g()); + s.value = "goodbye"; + EXPECT_EQ("goodbye", g()); +} + +TEST(BindTest, StoreByPointer) { + NonCopyable s("hello"); + auto f = absl::bind_front(&NonCopyable::value, &s); + EXPECT_EQ("hello", f()); + EXPECT_EQ(&s.value, &f()); + auto g = std::move(f); + EXPECT_EQ("hello", g()); + EXPECT_EQ(&s.value, &g()); +} + +int Sink(std::unique_ptr<int> p) { + return *p; +} + +std::unique_ptr<int> Factory(int n) { return absl::make_unique<int>(n); } + +TEST(BindTest, NonCopyableArg) { + EXPECT_EQ(42, absl::bind_front(Sink)(absl::make_unique<int>(42))); + EXPECT_EQ(42, absl::bind_front(Sink, absl::make_unique<int>(42))()); +} + +TEST(BindTest, NonCopyableResult) { + EXPECT_THAT(absl::bind_front(Factory)(42), ::testing::Pointee(42)); + EXPECT_THAT(absl::bind_front(Factory, 42)(), ::testing::Pointee(42)); +} + +// is_copy_constructible<FalseCopyable<unique_ptr<T>> is true but an attempt to +// instantiate the copy constructor leads to a compile error. This is similar +// to how standard containers behave. +template <class T> +struct FalseCopyable { + FalseCopyable() {} + FalseCopyable(const FalseCopyable& other) : m(other.m) {} + FalseCopyable(FalseCopyable&& other) : m(std::move(other.m)) {} + T m; +}; + +int GetMember(FalseCopyable<std::unique_ptr<int>> x) { return *x.m; } + +TEST(BindTest, WrappedMoveOnly) { + FalseCopyable<std::unique_ptr<int>> x; + x.m = absl::make_unique<int>(42); + auto f = absl::bind_front(&GetMember, std::move(x)); + EXPECT_EQ(42, std::move(f)()); +} + +int Plus(int a, int b) { return a + b; } + +TEST(BindTest, ConstExpr) { + constexpr auto f = absl::bind_front(CharAt); + EXPECT_EQ(f("ABC", 1), 'B'); + static constexpr int five = 5; + constexpr auto plus5 = absl::bind_front(Plus, five); + EXPECT_EQ(plus5(1), 6); + + // There seems to be a bug in MSVC dealing constexpr construction of + // char[]. Notice 'plus5' above; 'int' works just fine. +#if !(defined(_MSC_VER) && _MSC_VER < 1910) + static constexpr char data[] = "DEF"; + constexpr auto g = absl::bind_front(CharAt, data); + EXPECT_EQ(g(1), 'E'); +#endif +} + +struct ManglingCall { + int operator()(int, double, std::string) const { return 0; } +}; + +TEST(BindTest, Mangling) { + // We just want to generate a particular instantiation to see its mangling. + absl::bind_front(ManglingCall{}, 1, 3.3)("A"); +} + +} // namespace |