element-ios/Riot/PropertyWrappers/UserDefaultsBackedPropertyW...

62 lines
1.6 KiB
Swift

//
// Copyright 2021-2024 New Vector Ltd.
//
// SPDX-License-Identifier: AGPL-3.0-only
// Please see LICENSE in the repository root for full details.
//
// Taken from https://www.swiftbysundell.com/articles/property-wrappers-in-swift/
import Foundation
@propertyWrapper
struct UserDefault<Value> {
private let key: String
private let defaultValue: Value
private let storage: UserDefaults
init(key: String, defaultValue: Value, storage: UserDefaults = .standard) {
self.defaultValue = defaultValue
self.key = key
self.storage = storage
}
var wrappedValue: Value {
get {
let value = storage.value(forKey: key) as? Value
return value ?? defaultValue
}
set {
if let optional = newValue as? AnyOptional, optional.isNil {
storage.removeObject(forKey: key)
} else {
storage.setValue(newValue, forKey: key)
}
let tmpKey = key
DispatchQueue.main.async {
NotificationCenter.default.post(name: .userDefaultValueUpdated,
object: tmpKey)
}
}
}
}
extension UserDefault where Value: ExpressibleByNilLiteral {
init(key: String, storage: UserDefaults = .standard) {
self.init(key: key, defaultValue: nil, storage: storage)
}
}
private protocol AnyOptional {
var isNil: Bool { get }
}
extension Optional: AnyOptional {
var isNil: Bool { self == nil }
}
extension Notification.Name {
static let userDefaultValueUpdated = Notification.Name("userDefaultValueUpdated")
}