Ilya Matyukhin | 4f5d680 | 2021-02-22 13:10:55 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2021 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 | namespace aidl::android::hardware::biometrics::fingerprint { |
| 20 | |
| 21 | // Interface for representing parameterless functions. Unlike std::function<void()>, this can also |
| 22 | // represent move-only lambdas. |
| 23 | class Callable { |
| 24 | public: |
| 25 | virtual void operator()() = 0; |
| 26 | virtual ~Callable() = default; |
| 27 | |
| 28 | // Creates a heap-allocated Callable instance from any function object. |
| 29 | template <typename T> |
| 30 | static std::unique_ptr<Callable> from(T func); |
| 31 | |
| 32 | private: |
| 33 | template <typename T> |
| 34 | class AnyFuncWrapper; |
| 35 | }; |
| 36 | |
| 37 | // Private helper class for wrapping any function object into a Callable. |
| 38 | template <typename T> |
| 39 | class Callable::AnyFuncWrapper : public Callable { |
| 40 | public: |
| 41 | explicit AnyFuncWrapper(T func) : mFunc(std::move(func)) {} |
| 42 | |
| 43 | void operator()() override { mFunc(); } |
| 44 | |
| 45 | private: |
| 46 | T mFunc; |
| 47 | }; |
| 48 | |
| 49 | template <typename T> |
| 50 | std::unique_ptr<Callable> Callable::from(T func) { |
| 51 | return std::make_unique<AnyFuncWrapper<T>>(std::move(func)); |
| 52 | } |
| 53 | |
| 54 | } // namespace aidl::android::hardware::biometrics::fingerprint |