Using a property wrapper for UserDefaults backed application settings…

… (RiotSettings).

Riot/PropertyWrappers/UserDefaultsBackedPropertyWrapper.swift

@@ -0,0 +1,61 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+// 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)
+            }
+        }
+    }
+}
+
+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 }
+}

RiotNSE/target.yml

@@ -59,3 +59,4 @@ targets:
     - path: ../Riot/Categories/String.swift
     - path: ../Riot/Categories/Character.swift
     - path: ../Riot/Managers/Widgets/WidgetConstants.m
+    - path: ../Riot/PropertyWrappers/UserDefaultsBackedPropertyWrapper.swift

RiotShareExtension/target.yml

@@ -56,6 +56,7 @@ targets:
     - path: ../Riot/Categories/UISearchBar.swift
     - path: ../Riot/Categories/String.swift
     - path: ../Riot/Modules/Common/Recents/CellData/RecentCellData.m
+    - path: ../Riot/PropertyWrappers/UserDefaultsBackedPropertyWrapper.swift
     - path: ../Riot/Modules/Common/SegmentedViewController/SegmentedViewController.xib
       buildPhase: resources
     - path: ../Riot/Assets/en.lproj/Vector.strings

RiotTests/target.yml

@@ -64,3 +64,4 @@ targets:
     - path: ../Riot/Managers/Settings/RiotSettings.swift
     - path: ../Riot/Managers/EncryptionKeyManager/EncryptionKeyManager.swift
     - path: ../Riot/Managers/KeyValueStorage/
+    - path: ../Riot/PropertyWrappers/UserDefaultsBackedPropertyWrapper.swift

SiriIntents/target.yml

@@ -48,3 +48,4 @@ targets:
     - path: ../Riot/Managers/Settings/RiotSettings.swift
     - path: ../Riot/Managers/EncryptionKeyManager/EncryptionKeyManager.swift
     - path: ../Riot/Managers/KeyValueStorage
+    - path: ../Riot/PropertyWrappers/UserDefaultsBackedPropertyWrapper.swift

changelog.d/pr-4755.misc

@@ -0,0 +1 @@
+Using a property wrapper for UserDefaults backed application settings (RiotSettings).