mirror of
https://github.com/kidfromjupiter/nearby.git
synced 2026-09-14 14:46:12 -04:00
120 lines
3.6 KiB
C++
120 lines
3.6 KiB
C++
// Copyright 2024 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef PLATFORM_BASE_EXPECTED_H_
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#define PLATFORM_BASE_EXPECTED_H_
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#include <optional>
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#include <string>
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#include <utility>
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#include <variant>
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#include "proto/connections_enums.pb.h"
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namespace nearby {
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class Error {
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public:
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Error() = default;
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explicit Error(location::nearby::proto::connections::OperationResultCode
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operation_result_code)
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: operation_result_code_(operation_result_code) {}
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bool success() const {
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return operation_result_code_ == location::nearby::proto::connections::
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OperationResultCode::DETAIL_SUCCESS;
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}
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bool failure() const { return !success(); }
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std::optional<location::nearby::proto::connections::OperationResultCode>
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operation_result_code() const {
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return operation_result_code_;
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}
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static Error Success() { return Error(); }
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private:
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location::nearby::proto::connections::OperationResultCode
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operation_result_code_ = location::nearby::proto::connections::
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OperationResultCode::DETAIL_UNKNOWN;
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};
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// Forward declare.
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template <typename E>
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class Unexpected;
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template <typename T, typename E>
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class Expected {
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public:
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constexpr Expected(T value) : data_(std::move(value)) {} // NOLINT
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constexpr Expected(Unexpected<E> u); // NOLINT
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constexpr operator bool() const { // NOLINT
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return has_value();
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}
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constexpr T& operator*() & { return value(); }
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constexpr const T& operator*() const& { return value(); }
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constexpr T&& operator*() && { return std::move(value()); }
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constexpr const T& operator*() const&& { return std::move(value()); }
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constexpr T* operator->() { return &value(); }
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constexpr const T* operator->() const { return &value(); }
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constexpr bool has_value() const { return std::holds_alternative<T>(data_); }
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constexpr bool has_error() const { return std::holds_alternative<E>(data_); }
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constexpr T& value() & { return std::get<T>(data_); }
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constexpr const T& value() const& { return std::get<T>(data_); }
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constexpr T&& value() && { return std::get<T>(std::move(data_)); }
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constexpr const T& value() const&& { return std::get<T>(std::move(data_)); }
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constexpr E& error() & { return std::get<E>(data_); }
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constexpr const E& error() const& { return std::get<E>(data_); }
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constexpr E&& error() && { return std::get<E>(std::move(data_)); }
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constexpr const E&& error() const&& { return std::get<E>(std::move(data_)); }
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private:
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std::variant<T, E> data_;
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};
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template <typename E>
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class Unexpected {
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public:
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constexpr Unexpected(E error) : error_(std::move(error)) {} // NOLINT
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private:
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template <typename, typename>
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friend class Expected;
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E error_;
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};
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Unexpected(const char*) -> Unexpected<std::string>;
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template <typename T, typename E>
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constexpr Expected<T, E>::Expected(Unexpected<E> u)
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: data_(std::move(u.error_)) {}
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template <typename T>
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class ErrorOr : public Expected<T, Error> {
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public:
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using Expected<T, Error>::Expected;
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};
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} // namespace nearby
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#endif // PLATFORM_BASE_EXPECTED_H_
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