John Reck | 8e539ca | 2018-11-15 15:21:29 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2018 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #pragma once |
| 18 | |
| 19 | #include <variant> |
| 20 | #include <log/log.h> |
| 21 | |
| 22 | namespace android::uirenderer { |
| 23 | |
| 24 | template <typename E> |
| 25 | struct Error { |
| 26 | E error; |
| 27 | }; |
| 28 | |
| 29 | template <typename R, typename E> |
| 30 | class Result { |
| 31 | public: |
| 32 | Result(const R& r) : result(std::forward<R>(r)) {} |
| 33 | Result(R&& r) : result(std::forward<R>(r)) {} |
| 34 | Result(Error<E>&& error) : result(std::forward<Error<E>>(error)) {} |
| 35 | |
| 36 | operator bool() const { |
| 37 | return result.index() == 0; |
| 38 | } |
| 39 | |
| 40 | R unwrap() const { |
| 41 | LOG_ALWAYS_FATAL_IF(result.index() == 1, "unwrap called on error value!"); |
| 42 | return std::get<R>(result); |
| 43 | } |
| 44 | |
| 45 | E error() const { |
| 46 | LOG_ALWAYS_FATAL_IF(result.index() == 0, "No error to get from Result"); |
| 47 | return std::get<Error<E>>(result).error; |
| 48 | } |
| 49 | |
| 50 | private: |
| 51 | std::variant<R, Error<E>> result; |
| 52 | }; |
| 53 | |
Chris Blume | 7b8a808 | 2018-11-30 15:51:58 -0800 | [diff] [blame] | 54 | } // namespace android::uirenderer |