From e4c8d0eb8ef4acb5d7a4252b3b87feb391ef7e41 Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Fri, 18 Oct 2019 09:06:29 -0700 Subject: Export of internal Abseil changes -- a9ac6567c0933d786d68c10011e3f3ff9deedf89 by Greg Falcon : Add absl::FunctionRef, a type analogous to the proposed C++23 std::function_ref. Like std::function, FunctionRef can be used to type-erase any callable (invokable) object. However, FunctionRef works by reference: it does not store a copy of the type-erased object. If the wrapped object is destroyed before the FunctionRef, the reference becomes dangling. FunctionRef relates to std::function in much the same way that string_view relates to std::string. Because of these limitations, FunctionRef is best used only as a function argument type, and only where the function will be invoked immediately (rather than saved for later use). When `const std::function<...>&` is used in this way, `absl::FunctionRef<...>` is a better-performing replacement. PiperOrigin-RevId: 275484044 -- 1f7c4df3760f8b93e5a5baf40b070eca1d3f4c98 by Abseil Team : Add FastHexToBufferZeroPad16() function for blazingly fast hex encoding of uint64_t. PiperOrigin-RevId: 275420901 -- 08d48ac004eba57cf2f1ada827181a2995f74807 by Abseil Team : Avoid applying the workaround for MSVC's static initialization problems when using clang-cl. PiperOrigin-RevId: 275366326 -- 40be82bd2b34670b5458c0a72a0475086153c2d6 by Abseil Team : Added comments to SimpleAtof()/SimpleAtod() that clarify that they always use the "C" locale, unlike the standard functions strtod() and strtof() referenced now in the comments. PiperOrigin-RevId: 275355815 -- 086779dacb3f6f2b3ab59947e94e79046bdb1fe1 by Jorg Brown : Move the hex conversion table used by escaping.cc into numbers.h so that other parts of Abseil can more efficiently access it. PiperOrigin-RevId: 275331251 -- 3c4ed1b04e55d96a40cbe70fb70929ffbb0c0432 by Abseil Team : Avoid applying the workaround for MSVC's static initialization problems when using clang-cl. PiperOrigin-RevId: 275323858 -- 56ceb58ab688c3761978308609b09a1ac2739c9a by Derek Mauro : Add script for testing on Alpine Linux (for musl test coverage) PiperOrigin-RevId: 275321244 GitOrigin-RevId: a9ac6567c0933d786d68c10011e3f3ff9deedf89 Change-Id: I39799fa03768ddb44f3166200c860e1da4461807 --- absl/functional/function_ref_test.cc | 255 +++++++++++++++++++++++++++++++++++ 1 file changed, 255 insertions(+) create mode 100644 absl/functional/function_ref_test.cc (limited to 'absl/functional/function_ref_test.cc') diff --git a/absl/functional/function_ref_test.cc b/absl/functional/function_ref_test.cc new file mode 100644 index 00000000..90829db0 --- /dev/null +++ b/absl/functional/function_ref_test.cc @@ -0,0 +1,255 @@ +// Copyright 2019 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/function_ref.h" + +#include + +#include "gmock/gmock.h" +#include "gtest/gtest.h" +#include "absl/container/internal/test_instance_tracker.h" +#include "absl/memory/memory.h" + +namespace absl { +namespace { + +void RunFun(FunctionRef f) { f(); } + +TEST(FunctionRefTest, Lambda) { + bool ran = false; + RunFun([&] { ran = true; }); + EXPECT_TRUE(ran); +} + +int Function() { return 1337; } + +TEST(FunctionRefTest, Function1) { + FunctionRef ref(&Function); + EXPECT_EQ(1337, ref()); +} + +TEST(FunctionRefTest, Function2) { + FunctionRef ref(Function); + EXPECT_EQ(1337, ref()); +} + +int NoExceptFunction() noexcept { return 1337; } + +// TODO(jdennett): Add a test for noexcept member functions. +TEST(FunctionRefTest, NoExceptFunction) { + FunctionRef ref(NoExceptFunction); + EXPECT_EQ(1337, ref()); +} + +TEST(FunctionRefTest, ForwardsArgs) { + auto l = [](std::unique_ptr i) { return *i; }; + FunctionRef)> ref(l); + EXPECT_EQ(42, ref(absl::make_unique(42))); +} + +TEST(FunctionRef, ReturnMoveOnly) { + auto l = [] { return absl::make_unique(29); }; + FunctionRef()> ref(l); + EXPECT_EQ(29, *ref()); +} + +TEST(FunctionRef, ManyArgs) { + auto l = [](int a, int b, int c) { return a + b + c; }; + FunctionRef ref(l); + EXPECT_EQ(6, ref(1, 2, 3)); +} + +TEST(FunctionRef, VoidResultFromNonVoidFunctor) { + bool ran = false; + auto l = [&]() -> int { + ran = true; + return 2; + }; + FunctionRef ref(l); + ref(); + EXPECT_TRUE(ran); +} + +TEST(FunctionRef, CastFromDerived) { + struct Base {}; + struct Derived : public Base {}; + + Derived d; + auto l1 = [&](Base* b) { EXPECT_EQ(&d, b); }; + FunctionRef ref1(l1); + ref1(&d); + + auto l2 = [&]() -> Derived* { return &d; }; + FunctionRef ref2(l2); + EXPECT_EQ(&d, ref2()); +} + +TEST(FunctionRef, VoidResultFromNonVoidFuncton) { + FunctionRef ref(Function); + ref(); +} + +TEST(FunctionRef, MemberPtr) { + struct S { + int i; + }; + + S s{1100111}; + auto mem_ptr = &S::i; + FunctionRef ref(mem_ptr); + EXPECT_EQ(1100111, ref(s)); +} + +TEST(FunctionRef, MemberFun) { + struct S { + int i; + int get_i() const { return i; } + }; + + S s{22}; + auto mem_fun_ptr = &S::get_i; + FunctionRef ref(mem_fun_ptr); + EXPECT_EQ(22, ref(s)); +} + +TEST(FunctionRef, MemberFunRefqualified) { + struct S { + int i; + int get_i() && { return i; } + }; + auto mem_fun_ptr = &S::get_i; + S s{22}; + FunctionRef ref(mem_fun_ptr); + EXPECT_EQ(22, ref(std::move(s))); +} + +#if !defined(_WIN32) && defined(GTEST_HAS_DEATH_TEST) + +TEST(FunctionRef, MemberFunRefqualifiedNull) { + struct S { + int i; + int get_i() && { return i; } + }; + auto mem_fun_ptr = &S::get_i; + mem_fun_ptr = nullptr; + EXPECT_DEBUG_DEATH({ FunctionRef ref(mem_fun_ptr); }, ""); +} + +TEST(FunctionRef, NullMemberPtrAssertFails) { + struct S { + int i; + }; + using MemberPtr = int S::*; + MemberPtr mem_ptr = nullptr; + EXPECT_DEBUG_DEATH({ FunctionRef ref(mem_ptr); }, ""); +} + +#endif // GTEST_HAS_DEATH_TEST + +TEST(FunctionRef, CopiesAndMovesPerPassByValue) { + absl::test_internal::InstanceTracker tracker; + absl::test_internal::CopyableMovableInstance instance(0); + auto l = [](absl::test_internal::CopyableMovableInstance) {}; + FunctionRef ref(l); + ref(instance); + EXPECT_EQ(tracker.copies(), 1); + EXPECT_EQ(tracker.moves(), 1); +} + +TEST(FunctionRef, CopiesAndMovesPerPassByRef) { + absl::test_internal::InstanceTracker tracker; + absl::test_internal::CopyableMovableInstance instance(0); + auto l = [](const absl::test_internal::CopyableMovableInstance&) {}; + FunctionRef ref(l); + ref(instance); + EXPECT_EQ(tracker.copies(), 0); + EXPECT_EQ(tracker.moves(), 0); +} + +TEST(FunctionRef, CopiesAndMovesPerPassByValueCallByMove) { + absl::test_internal::InstanceTracker tracker; + absl::test_internal::CopyableMovableInstance instance(0); + auto l = [](absl::test_internal::CopyableMovableInstance) {}; + FunctionRef ref(l); + ref(std::move(instance)); + EXPECT_EQ(tracker.copies(), 0); + EXPECT_EQ(tracker.moves(), 2); +} + +TEST(FunctionRef, CopiesAndMovesPerPassByValueToRef) { + absl::test_internal::InstanceTracker tracker; + absl::test_internal::CopyableMovableInstance instance(0); + auto l = [](const absl::test_internal::CopyableMovableInstance&) {}; + FunctionRef ref(l); + ref(std::move(instance)); + EXPECT_EQ(tracker.copies(), 0); + EXPECT_EQ(tracker.moves(), 1); +} + +TEST(FunctionRef, PassByValueTypes) { + using absl::functional_internal::Invoker; + using absl::functional_internal::VoidPtr; + using absl::test_internal::CopyableMovableInstance; + struct Trivial { + void* p[2]; + }; + struct LargeTrivial { + void* p[3]; + }; + + static_assert(std::is_same, void (*)(VoidPtr, int)>::value, + "Scalar types should be passed by value"); + static_assert( + std::is_same, void (*)(VoidPtr, Trivial)>::value, + "Small trivial types should be passed by value"); + static_assert(std::is_same, + void (*)(VoidPtr, LargeTrivial &&)>::value, + "Large trivial types should be passed by rvalue reference"); + static_assert( + std::is_same, + void (*)(VoidPtr, CopyableMovableInstance &&)>::value, + "Types with copy/move ctor should be passed by rvalue reference"); + + // References are passed as references. + static_assert( + std::is_same, void (*)(VoidPtr, int&)>::value, + "Reference types should be preserved"); + static_assert( + std::is_same, + void (*)(VoidPtr, CopyableMovableInstance&)>::value, + "Reference types should be preserved"); + static_assert( + std::is_same, + void (*)(VoidPtr, CopyableMovableInstance &&)>::value, + "Reference types should be preserved"); + + // Make sure the address of an object received by reference is the same as the + // addess of the object passed by the caller. + { + LargeTrivial obj; + auto test = [&obj](LargeTrivial& input) { ASSERT_EQ(&input, &obj); }; + absl::FunctionRef ref(test); + ref(obj); + } + + { + Trivial obj; + auto test = [&obj](Trivial& input) { ASSERT_EQ(&input, &obj); }; + absl::FunctionRef ref(test); + ref(obj); + } +} + +} // namespace +} // namespace absl -- cgit v1.2.3