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author | Colin Cross <ccross@android.com> | 2022-04-13 03:15:00 +0000 |
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committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | 2022-04-13 03:15:00 +0000 |
commit | 6c9587948173932b64d97c288a947e43d2a2ac14 (patch) | |
tree | 2ce94d7f0804ccb77d1fa9b2a1bca00eecdff1e2 /third_party/abseil-cpp/absl/cleanup | |
parent | f60eaea2240ba9e1c508e8e0c91d39ee9fc47be5 (diff) | |
parent | 43d8f56cdc20240b37c36bf417dd0d6999bce738 (diff) | |
download | webrtc-android13-qpr3-s12-release.tar.gz |
Merge changes I0ab600cd,I1e74c64a am: 798f3afdf6 am: 2f9c4b2c3b am: a9167328fc am: 7563023510 am: 43d8f56cdcandroid-13.0.0_r83android-13.0.0_r82android-13.0.0_r81android-13.0.0_r80android-13.0.0_r79android-13.0.0_r78android-13.0.0_r77android-13.0.0_r76android-13.0.0_r75android-13.0.0_r74android-13.0.0_r73android-13.0.0_r72android-13.0.0_r71android-13.0.0_r70android-13.0.0_r69android-13.0.0_r68android-13.0.0_r67android-13.0.0_r66android-13.0.0_r65android-13.0.0_r64android-13.0.0_r63android-13.0.0_r62android-13.0.0_r61android-13.0.0_r60android-13.0.0_r59android-13.0.0_r58android-13.0.0_r56android-13.0.0_r54android-13.0.0_r53android-13.0.0_r52android-13.0.0_r51android-13.0.0_r50android-13.0.0_r49android-13.0.0_r48android-13.0.0_r47android-13.0.0_r46android-13.0.0_r45android-13.0.0_r44android-13.0.0_r43android-13.0.0_r42android-13.0.0_r41android-13.0.0_r40android-13.0.0_r39android-13.0.0_r38android-13.0.0_r37android-13.0.0_r36android-13.0.0_r35android-13.0.0_r34android-13.0.0_r33android-13.0.0_r32android13-qpr3-s9-releaseandroid13-qpr3-s8-releaseandroid13-qpr3-s7-releaseandroid13-qpr3-s6-releaseandroid13-qpr3-s5-releaseandroid13-qpr3-s4-releaseandroid13-qpr3-s3-releaseandroid13-qpr3-s2-releaseandroid13-qpr3-s14-releaseandroid13-qpr3-s13-releaseandroid13-qpr3-s12-releaseandroid13-qpr3-s11-releaseandroid13-qpr3-s10-releaseandroid13-qpr3-s1-releaseandroid13-qpr3-releaseandroid13-qpr3-c-s8-releaseandroid13-qpr3-c-s7-releaseandroid13-qpr3-c-s6-releaseandroid13-qpr3-c-s5-releaseandroid13-qpr3-c-s4-releaseandroid13-qpr3-c-s3-releaseandroid13-qpr3-c-s2-releaseandroid13-qpr3-c-s12-releaseandroid13-qpr3-c-s11-releaseandroid13-qpr3-c-s10-releaseandroid13-qpr3-c-s1-releaseandroid13-qpr2-s9-releaseandroid13-qpr2-s8-releaseandroid13-qpr2-s7-releaseandroid13-qpr2-s6-releaseandroid13-qpr2-s5-releaseandroid13-qpr2-s3-releaseandroid13-qpr2-s2-releaseandroid13-qpr2-s12-releaseandroid13-qpr2-s11-releaseandroid13-qpr2-s10-releaseandroid13-qpr2-s1-releaseandroid13-qpr2-releaseandroid13-qpr2-b-s1-releaseandroid13-d4-s2-releaseandroid13-d4-s1-releaseandroid13-d4-release
Original change: https://android-review.googlesource.com/c/platform/external/webrtc/+/2062410
Change-Id: I1aa9f459b825711b800cc65782979943a9151ec7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
Diffstat (limited to 'third_party/abseil-cpp/absl/cleanup')
-rw-r--r-- | third_party/abseil-cpp/absl/cleanup/BUILD.bazel | 65 | ||||
-rw-r--r-- | third_party/abseil-cpp/absl/cleanup/CMakeLists.txt | 55 | ||||
-rw-r--r-- | third_party/abseil-cpp/absl/cleanup/cleanup.h | 140 | ||||
-rw-r--r-- | third_party/abseil-cpp/absl/cleanup/cleanup_test.cc | 311 | ||||
-rw-r--r-- | third_party/abseil-cpp/absl/cleanup/internal/cleanup.h | 100 |
5 files changed, 671 insertions, 0 deletions
diff --git a/third_party/abseil-cpp/absl/cleanup/BUILD.bazel b/third_party/abseil-cpp/absl/cleanup/BUILD.bazel new file mode 100644 index 0000000000..2154d9f1a3 --- /dev/null +++ b/third_party/abseil-cpp/absl/cleanup/BUILD.bazel @@ -0,0 +1,65 @@ +# Copyright 2021 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. + +load( + "//absl:copts/configure_copts.bzl", + "ABSL_DEFAULT_COPTS", + "ABSL_DEFAULT_LINKOPTS", + "ABSL_TEST_COPTS", +) + +package(default_visibility = ["//visibility:public"]) + +licenses(["notice"]) + +cc_library( + name = "cleanup_internal", + hdrs = ["internal/cleanup.h"], + copts = ABSL_DEFAULT_COPTS, + linkopts = ABSL_DEFAULT_LINKOPTS, + deps = [ + "//absl/base:base_internal", + "//absl/base:core_headers", + "//absl/utility", + ], +) + +cc_library( + name = "cleanup", + hdrs = [ + "cleanup.h", + ], + copts = ABSL_DEFAULT_COPTS, + linkopts = ABSL_DEFAULT_LINKOPTS, + deps = [ + ":cleanup_internal", + "//absl/base:config", + "//absl/base:core_headers", + ], +) + +cc_test( + name = "cleanup_test", + size = "small", + srcs = [ + "cleanup_test.cc", + ], + copts = ABSL_TEST_COPTS, + deps = [ + ":cleanup", + "//absl/base:config", + "//absl/utility", + "@com_google_googletest//:gtest_main", + ], +) diff --git a/third_party/abseil-cpp/absl/cleanup/CMakeLists.txt b/third_party/abseil-cpp/absl/cleanup/CMakeLists.txt new file mode 100644 index 0000000000..26a6d0dce3 --- /dev/null +++ b/third_party/abseil-cpp/absl/cleanup/CMakeLists.txt @@ -0,0 +1,55 @@ +# Copyright 2021 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. + +absl_cc_library( + NAME + cleanup_internal + HDRS + "internal/cleanup.h" + COPTS + ${ABSL_DEFAULT_COPTS} + DEPS + absl::base_internal + absl::core_headers + absl::utility + PUBLIC +) + +absl_cc_library( + NAME + cleanup + HDRS + "cleanup.h" + COPTS + ${ABSL_DEFAULT_COPTS} + DEPS + absl::cleanup_internal + absl::config + absl::core_headers + PUBLIC +) + +absl_cc_test( + NAME + cleanup_test + SRCS + "cleanup_test.cc" + COPTS + ${ABSL_TEST_COPTS} + DEPS + absl::cleanup + absl::config + absl::utility + GTest::gmock_main +) diff --git a/third_party/abseil-cpp/absl/cleanup/cleanup.h b/third_party/abseil-cpp/absl/cleanup/cleanup.h new file mode 100644 index 0000000000..960ccd080e --- /dev/null +++ b/third_party/abseil-cpp/absl/cleanup/cleanup.h @@ -0,0 +1,140 @@ +// Copyright 2021 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. +// +// ----------------------------------------------------------------------------- +// File: cleanup.h +// ----------------------------------------------------------------------------- +// +// `absl::Cleanup` implements the scope guard idiom, invoking the contained +// callback's `operator()() &&` on scope exit. +// +// Example: +// +// ``` +// absl::Status CopyGoodData(const char* source_path, const char* sink_path) { +// FILE* source_file = fopen(source_path, "r"); +// if (source_file == nullptr) { +// return absl::NotFoundError("No source file"); // No cleanups execute +// } +// +// // C++17 style cleanup using class template argument deduction +// absl::Cleanup source_closer = [source_file] { fclose(source_file); }; +// +// FILE* sink_file = fopen(sink_path, "w"); +// if (sink_file == nullptr) { +// return absl::NotFoundError("No sink file"); // First cleanup executes +// } +// +// // C++11 style cleanup using the factory function +// auto sink_closer = absl::MakeCleanup([sink_file] { fclose(sink_file); }); +// +// Data data; +// while (ReadData(source_file, &data)) { +// if (!data.IsGood()) { +// absl::Status result = absl::FailedPreconditionError("Read bad data"); +// return result; // Both cleanups execute +// } +// SaveData(sink_file, &data); +// } +// +// return absl::OkStatus(); // Both cleanups execute +// } +// ``` +// +// Methods: +// +// `std::move(cleanup).Cancel()` will prevent the callback from executing. +// +// `std::move(cleanup).Invoke()` will execute the callback early, before +// destruction, and prevent the callback from executing in the destructor. +// +// Usage: +// +// `absl::Cleanup` is not an interface type. It is only intended to be used +// within the body of a function. It is not a value type and instead models a +// control flow construct. Check out `defer` in Golang for something similar. + +#ifndef ABSL_CLEANUP_CLEANUP_H_ +#define ABSL_CLEANUP_CLEANUP_H_ + +#include <utility> + +#include "absl/base/config.h" +#include "absl/base/macros.h" +#include "absl/cleanup/internal/cleanup.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN + +template <typename Arg, typename Callback = void()> +class ABSL_MUST_USE_RESULT Cleanup final { + static_assert(cleanup_internal::WasDeduced<Arg>(), + "Explicit template parameters are not supported."); + + static_assert(cleanup_internal::ReturnsVoid<Callback>(), + "Callbacks that return values are not supported."); + + public: + Cleanup(Callback callback) : storage_(std::move(callback)) {} // NOLINT + + Cleanup(Cleanup&& other) = default; + + void Cancel() && { + ABSL_HARDENING_ASSERT(storage_.IsCallbackEngaged()); + storage_.DestroyCallback(); + } + + void Invoke() && { + ABSL_HARDENING_ASSERT(storage_.IsCallbackEngaged()); + storage_.InvokeCallback(); + storage_.DestroyCallback(); + } + + ~Cleanup() { + if (storage_.IsCallbackEngaged()) { + storage_.InvokeCallback(); + storage_.DestroyCallback(); + } + } + + private: + cleanup_internal::Storage<Callback> storage_; +}; + +// `absl::Cleanup c = /* callback */;` +// +// C++17 type deduction API for creating an instance of `absl::Cleanup` +#if defined(ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION) +template <typename Callback> +Cleanup(Callback callback) -> Cleanup<cleanup_internal::Tag, Callback>; +#endif // defined(ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION) + +// `auto c = absl::MakeCleanup(/* callback */);` +// +// C++11 type deduction API for creating an instance of `absl::Cleanup` +template <typename... Args, typename Callback> +absl::Cleanup<cleanup_internal::Tag, Callback> MakeCleanup(Callback callback) { + static_assert(cleanup_internal::WasDeduced<cleanup_internal::Tag, Args...>(), + "Explicit template parameters are not supported."); + + static_assert(cleanup_internal::ReturnsVoid<Callback>(), + "Callbacks that return values are not supported."); + + return {std::move(callback)}; +} + +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_CLEANUP_CLEANUP_H_ diff --git a/third_party/abseil-cpp/absl/cleanup/cleanup_test.cc b/third_party/abseil-cpp/absl/cleanup/cleanup_test.cc new file mode 100644 index 0000000000..46b885899c --- /dev/null +++ b/third_party/abseil-cpp/absl/cleanup/cleanup_test.cc @@ -0,0 +1,311 @@ +// Copyright 2021 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/cleanup/cleanup.h" + +#include <functional> +#include <type_traits> +#include <utility> + +#include "gtest/gtest.h" +#include "absl/base/config.h" +#include "absl/utility/utility.h" + +namespace { + +using Tag = absl::cleanup_internal::Tag; + +template <typename Type1, typename Type2> +constexpr bool IsSame() { + return (std::is_same<Type1, Type2>::value); +} + +struct IdentityFactory { + template <typename Callback> + static Callback AsCallback(Callback callback) { + return Callback(std::move(callback)); + } +}; + +// `FunctorClass` is a type used for testing `absl::Cleanup`. It is intended to +// represent users that make their own move-only callback types outside of +// `std::function` and lambda literals. +class FunctorClass { + using Callback = std::function<void()>; + + public: + explicit FunctorClass(Callback callback) : callback_(std::move(callback)) {} + + FunctorClass(FunctorClass&& other) + : callback_(absl::exchange(other.callback_, Callback())) {} + + FunctorClass(const FunctorClass&) = delete; + + FunctorClass& operator=(const FunctorClass&) = delete; + + FunctorClass& operator=(FunctorClass&&) = delete; + + void operator()() const& = delete; + + void operator()() && { + ASSERT_TRUE(callback_); + callback_(); + callback_ = nullptr; + } + + private: + Callback callback_; +}; + +struct FunctorClassFactory { + template <typename Callback> + static FunctorClass AsCallback(Callback callback) { + return FunctorClass(std::move(callback)); + } +}; + +struct StdFunctionFactory { + template <typename Callback> + static std::function<void()> AsCallback(Callback callback) { + return std::function<void()>(std::move(callback)); + } +}; + +using CleanupTestParams = + ::testing::Types<IdentityFactory, FunctorClassFactory, StdFunctionFactory>; +template <typename> +struct CleanupTest : public ::testing::Test {}; +TYPED_TEST_SUITE(CleanupTest, CleanupTestParams); + +bool fn_ptr_called = false; +void FnPtrFunction() { fn_ptr_called = true; } + +TYPED_TEST(CleanupTest, FactoryProducesCorrectType) { + { + auto callback = TypeParam::AsCallback([] {}); + auto cleanup = absl::MakeCleanup(std::move(callback)); + + static_assert( + IsSame<absl::Cleanup<Tag, decltype(callback)>, decltype(cleanup)>(), + ""); + } + + { + auto cleanup = absl::MakeCleanup(&FnPtrFunction); + + static_assert(IsSame<absl::Cleanup<Tag, void (*)()>, decltype(cleanup)>(), + ""); + } + + { + auto cleanup = absl::MakeCleanup(FnPtrFunction); + + static_assert(IsSame<absl::Cleanup<Tag, void (*)()>, decltype(cleanup)>(), + ""); + } +} + +#if defined(ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION) +TYPED_TEST(CleanupTest, CTADProducesCorrectType) { + { + auto callback = TypeParam::AsCallback([] {}); + absl::Cleanup cleanup = std::move(callback); + + static_assert( + IsSame<absl::Cleanup<Tag, decltype(callback)>, decltype(cleanup)>(), + ""); + } + + { + absl::Cleanup cleanup = &FnPtrFunction; + + static_assert(IsSame<absl::Cleanup<Tag, void (*)()>, decltype(cleanup)>(), + ""); + } + + { + absl::Cleanup cleanup = FnPtrFunction; + + static_assert(IsSame<absl::Cleanup<Tag, void (*)()>, decltype(cleanup)>(), + ""); + } +} + +TYPED_TEST(CleanupTest, FactoryAndCTADProduceSameType) { + { + auto callback = IdentityFactory::AsCallback([] {}); + auto factory_cleanup = absl::MakeCleanup(callback); + absl::Cleanup deduction_cleanup = callback; + + static_assert( + IsSame<decltype(factory_cleanup), decltype(deduction_cleanup)>(), ""); + } + + { + auto factory_cleanup = + absl::MakeCleanup(FunctorClassFactory::AsCallback([] {})); + absl::Cleanup deduction_cleanup = FunctorClassFactory::AsCallback([] {}); + + static_assert( + IsSame<decltype(factory_cleanup), decltype(deduction_cleanup)>(), ""); + } + + { + auto factory_cleanup = + absl::MakeCleanup(StdFunctionFactory::AsCallback([] {})); + absl::Cleanup deduction_cleanup = StdFunctionFactory::AsCallback([] {}); + + static_assert( + IsSame<decltype(factory_cleanup), decltype(deduction_cleanup)>(), ""); + } + + { + auto factory_cleanup = absl::MakeCleanup(&FnPtrFunction); + absl::Cleanup deduction_cleanup = &FnPtrFunction; + + static_assert( + IsSame<decltype(factory_cleanup), decltype(deduction_cleanup)>(), ""); + } + + { + auto factory_cleanup = absl::MakeCleanup(FnPtrFunction); + absl::Cleanup deduction_cleanup = FnPtrFunction; + + static_assert( + IsSame<decltype(factory_cleanup), decltype(deduction_cleanup)>(), ""); + } +} +#endif // defined(ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION) + +TYPED_TEST(CleanupTest, BasicUsage) { + bool called = false; + + { + auto cleanup = + absl::MakeCleanup(TypeParam::AsCallback([&called] { called = true; })); + EXPECT_FALSE(called); // Constructor shouldn't invoke the callback + } + + EXPECT_TRUE(called); // Destructor should invoke the callback +} + +TYPED_TEST(CleanupTest, BasicUsageWithFunctionPointer) { + fn_ptr_called = false; + + { + auto cleanup = absl::MakeCleanup(TypeParam::AsCallback(&FnPtrFunction)); + EXPECT_FALSE(fn_ptr_called); // Constructor shouldn't invoke the callback + } + + EXPECT_TRUE(fn_ptr_called); // Destructor should invoke the callback +} + +TYPED_TEST(CleanupTest, Cancel) { + bool called = false; + + { + auto cleanup = + absl::MakeCleanup(TypeParam::AsCallback([&called] { called = true; })); + EXPECT_FALSE(called); // Constructor shouldn't invoke the callback + + std::move(cleanup).Cancel(); + EXPECT_FALSE(called); // Cancel shouldn't invoke the callback + } + + EXPECT_FALSE(called); // Destructor shouldn't invoke the callback +} + +TYPED_TEST(CleanupTest, Invoke) { + bool called = false; + + { + auto cleanup = + absl::MakeCleanup(TypeParam::AsCallback([&called] { called = true; })); + EXPECT_FALSE(called); // Constructor shouldn't invoke the callback + + std::move(cleanup).Invoke(); + EXPECT_TRUE(called); // Invoke should invoke the callback + + called = false; // Reset tracker before destructor runs + } + + EXPECT_FALSE(called); // Destructor shouldn't invoke the callback +} + +TYPED_TEST(CleanupTest, Move) { + bool called = false; + + { + auto moved_from_cleanup = + absl::MakeCleanup(TypeParam::AsCallback([&called] { called = true; })); + EXPECT_FALSE(called); // Constructor shouldn't invoke the callback + + { + auto moved_to_cleanup = std::move(moved_from_cleanup); + EXPECT_FALSE(called); // Move shouldn't invoke the callback + } + + EXPECT_TRUE(called); // Destructor should invoke the callback + + called = false; // Reset tracker before destructor runs + } + + EXPECT_FALSE(called); // Destructor shouldn't invoke the callback +} + +int DestructionCount = 0; + +struct DestructionCounter { + void operator()() {} + + ~DestructionCounter() { ++DestructionCount; } +}; + +TYPED_TEST(CleanupTest, DestructorDestroys) { + { + auto cleanup = + absl::MakeCleanup(TypeParam::AsCallback(DestructionCounter())); + DestructionCount = 0; + } + + EXPECT_EQ(DestructionCount, 1); // Engaged cleanup destroys +} + +TYPED_TEST(CleanupTest, CancelDestroys) { + { + auto cleanup = + absl::MakeCleanup(TypeParam::AsCallback(DestructionCounter())); + DestructionCount = 0; + + std::move(cleanup).Cancel(); + EXPECT_EQ(DestructionCount, 1); // Cancel destroys + } + + EXPECT_EQ(DestructionCount, 1); // Canceled cleanup does not double destroy +} + +TYPED_TEST(CleanupTest, InvokeDestroys) { + { + auto cleanup = + absl::MakeCleanup(TypeParam::AsCallback(DestructionCounter())); + DestructionCount = 0; + + std::move(cleanup).Invoke(); + EXPECT_EQ(DestructionCount, 1); // Invoke destroys + } + + EXPECT_EQ(DestructionCount, 1); // Invoked cleanup does not double destroy +} + +} // namespace diff --git a/third_party/abseil-cpp/absl/cleanup/internal/cleanup.h b/third_party/abseil-cpp/absl/cleanup/internal/cleanup.h new file mode 100644 index 0000000000..2783fcb7c1 --- /dev/null +++ b/third_party/abseil-cpp/absl/cleanup/internal/cleanup.h @@ -0,0 +1,100 @@ +// Copyright 2021 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. + +#ifndef ABSL_CLEANUP_INTERNAL_CLEANUP_H_ +#define ABSL_CLEANUP_INTERNAL_CLEANUP_H_ + +#include <new> +#include <type_traits> +#include <utility> + +#include "absl/base/internal/invoke.h" +#include "absl/base/macros.h" +#include "absl/base/thread_annotations.h" +#include "absl/utility/utility.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN + +namespace cleanup_internal { + +struct Tag {}; + +template <typename Arg, typename... Args> +constexpr bool WasDeduced() { + return (std::is_same<cleanup_internal::Tag, Arg>::value) && + (sizeof...(Args) == 0); +} + +template <typename Callback> +constexpr bool ReturnsVoid() { + return (std::is_same<base_internal::invoke_result_t<Callback>, void>::value); +} + +template <typename Callback> +class Storage { + public: + Storage() = delete; + + explicit Storage(Callback callback) { + // Placement-new into a character buffer is used for eager destruction when + // the cleanup is invoked or cancelled. To ensure this optimizes well, the + // behavior is implemented locally instead of using an absl::optional. + ::new (GetCallbackBuffer()) Callback(std::move(callback)); + is_callback_engaged_ = true; + } + + Storage(Storage&& other) { + ABSL_HARDENING_ASSERT(other.IsCallbackEngaged()); + + ::new (GetCallbackBuffer()) Callback(std::move(other.GetCallback())); + is_callback_engaged_ = true; + + other.DestroyCallback(); + } + + Storage(const Storage& other) = delete; + + Storage& operator=(Storage&& other) = delete; + + Storage& operator=(const Storage& other) = delete; + + void* GetCallbackBuffer() { return static_cast<void*>(+callback_buffer_); } + + Callback& GetCallback() { + return *reinterpret_cast<Callback*>(GetCallbackBuffer()); + } + + bool IsCallbackEngaged() const { return is_callback_engaged_; } + + void DestroyCallback() { + is_callback_engaged_ = false; + GetCallback().~Callback(); + } + + void InvokeCallback() ABSL_NO_THREAD_SAFETY_ANALYSIS { + std::move(GetCallback())(); + } + + private: + bool is_callback_engaged_; + alignas(Callback) char callback_buffer_[sizeof(Callback)]; +}; + +} // namespace cleanup_internal + +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_CLEANUP_INTERNAL_CLEANUP_H_ |