1 /* 2 * Copyright (C) 2020 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 #ifndef ANDROIDFW_ERRORS_H_ 18 #define ANDROIDFW_ERRORS_H_ 19 20 #include <optional> 21 #include <variant> 22 23 #include <android-base/result.h> 24 25 namespace android { 26 27 enum class IOError { 28 // Used when reading a file residing on an IncFs file-system times out. 29 PAGES_MISSING = -1, 30 }; 31 32 // Represents an absent result or an I/O error. 33 using NullOrIOError = std::variant<std::nullopt_t, IOError>; 34 35 // Checks whether the result holds an unexpected I/O error. 36 template <typename T> IsIOError(const base::expected<T,NullOrIOError> result)37static inline bool IsIOError(const base::expected<T, NullOrIOError> result) { 38 return !result.has_value() && std::holds_alternative<IOError>(result.error()); 39 } 40 GetIOError(const NullOrIOError & error)41static inline IOError GetIOError(const NullOrIOError& error) { 42 return std::get<IOError>(error); 43 } 44 45 } // namespace android 46 47 #endif //ANDROIDFW_ERRORS_H_ 48