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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/cleanup.h | |
parent | f60eaea2240ba9e1c508e8e0c91d39ee9fc47be5 (diff) | |
parent | 43d8f56cdc20240b37c36bf417dd0d6999bce738 (diff) | |
download | webrtc-android13-d4-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/cleanup.h')
-rw-r--r-- | third_party/abseil-cpp/absl/cleanup/cleanup.h | 140 |
1 files changed, 140 insertions, 0 deletions
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_ |