Move to approach without any breaking changes

Read the file's value as soon as the state value is accessed for the
first time

Sources/Adwaita/Model/Data Flow/State.swift

@@ -37,7 +37,13 @@ public struct State<Value>: StateProtocol {
  /// Get and set the value without updating the views.
  public var rawValue: Value {
  get {
- content.storage.value as! Value
+ if let readValue, !content.fetched {
+ let newValue = readValue()
+ content.storage.value = newValue
+ content.fetched = true
+ return newValue
+ }
+ return content.storage.value as! Value
  }
  nonmutating set {
  content.storage.value = newValue
@@ -54,6 +60,8 @@ public struct State<Value>: StateProtocol {
 
  /// The function for updating the value in the settings file.
  private var writeValue: (() -> Void)?
+ /// The function for reading the value in the settings file.
+ var readValue: (() -> Value)?
 
  /// The value with an erased type.
  public var value: Any {
@@ -97,6 +105,8 @@ public struct State<Value>: StateProtocol {
  var internalStorage: Storage?
  /// The initial value.
  private var initialValue: Value
+ /// Whether the value has already been fetched from the file stored on the system.
+ var fetched = false
 
  /// Initialize the content.
  /// - Parameter storage: The storage.
@@ -159,15 +169,18 @@ public struct State<Value>: StateProtocol {
 
  /// Get the settings directory path.
  /// - Returns: The path.
- private func dirPath() -> URL {
- Self.userDataDir()
- .appendingPathComponent(content.storage.folder ?? GTUIApp.appID, isDirectory: true)
+ private func dirPath() -> URL? {
+ guard let folder = content.storage.folder ?? GTUIApp.appID else {
+ return nil
+ }
+ return Self.userDataDir()
+ .appendingPathComponent(folder, isDirectory: true)
  }
 
  /// Get the settings file path.
  /// - Returns: The path.
- private func filePath() -> URL {
- dirPath().appendingPathComponent("\(content.storage.key ?? "temporary").json")
+ private func filePath() -> URL? {
+ dirPath()?.appendingPathComponent("\(content.storage.key ?? "temporary").json")
  }
 
 }
@@ -187,40 +200,52 @@ extension State where Value: Codable {
  self.forceUpdates = forceUpdates
  content.storage.key = key
  content.storage.folder = folder
- checkFile()
- readValue()
+ let value = self
+ self.readValue = {
+ value.checkFile()
+ return value.readActualValue() ?? wrappedValue
+ }
  self.writeValue = writeCodableValue
  }
 
  /// Check whether the settings file exists, and, if not, create it.
  private func checkFile() {
  let fileManager = FileManager.default
- if !fileManager.fileExists(atPath: dirPath().path) {
+ guard let dirPath = dirPath(), let filePath = filePath() else {
+ print("Stored state value accessed before initializing app id.")
+ return
+ }
+ if !fileManager.fileExists(atPath: dirPath.path) {
  try? fileManager.createDirectory(
- at: .init(fileURLWithPath: dirPath().path),
+ at: .init(fileURLWithPath: dirPath.path),
  withIntermediateDirectories: true,
  attributes: nil
  )
  }
- if !fileManager.fileExists(atPath: filePath().path) {
- fileManager.createFile(atPath: filePath().path, contents: .init(), attributes: nil)
+ if !fileManager.fileExists(atPath: filePath.path) {
+ fileManager.createFile(atPath: filePath.path, contents: .init(), attributes: nil)
  }
  }
 
  /// Update the local value with the value from the file.
- private func readValue() {
- let data = try? Data(contentsOf: filePath())
- if let data, let value = try? JSONDecoder().decode(Value.self, from: data) {
- rawValue = value
+ private func readActualValue() -> Value? {
+ if let filePath = filePath(),
+ let data = try? Data(contentsOf: filePath),
+ let value = try? JSONDecoder().decode(Value.self, from: data) {
+ return value
  }
+ return nil
  }
 
  /// Update the value on the file with the local value.
  private func writeCodableValue() {
  let encoder = JSONEncoder()
  encoder.outputFormatting = .prettyPrinted
  let data = try? encoder.encode(rawValue)
- try? data?.write(to: filePath())
+ guard let filePath = filePath() else {
+ return
+ }
+ try? data?.write(to: filePath)
  }
 
 }

Sources/Adwaita/Model/User Interface/App/App.swift

@@ -24,7 +24,7 @@
 public protocol App {
 
  /// The app's application ID.
- static var id: String { get }
+ var id: String { get }
 
  /// The app's windows.
  @SceneBuilder var scene: Scene { get }
@@ -40,12 +40,8 @@ public protocol App {
 
 extension App {
 
- @available(*, deprecated, message: "The 'id' property is removed. Please use the new static id instead.")
- var id: String { Self.id }
-
  /// The application's entry point.
  public static func main() {
- GTUIApp.appID = Self.id
  let app = setupApp()
  app.run()
  }
@@ -55,7 +51,7 @@ extension App {
  /// To run the app, call the ``GTUIApp/run(automaticSetup:manualSetup:)`` function.
  public static func setupApp() -> GTUIApp {
  var appInstance = self.init()
- appInstance.app = GTUIApp(Self.id) { appInstance }
+ appInstance.app = GTUIApp(appInstance.id) { appInstance }
  GTUIApp.updateHandlers.append { force in
  var removeIndices: [Int] = []
  for (index, window) in appInstance.app.sceneStorage.enumerated() {
@@ -69,6 +65,7 @@ extension App {
  appInstance.app.sceneStorage.remove(at: index)
  }
  }
+ GTUIApp.appID = appInstance.id
  return appInstance.app
  }
 

Sources/Adwaita/Model/User Interface/App/GTUIApp.swift

@@ -13,7 +13,7 @@ public class GTUIApp {
  /// The handlers which are called when a state changes.
  static var updateHandlers: [(Bool) -> Void] = []
  /// The app's id for the file name for storing the data.
- static var appID: String!
+ static var appID: String?
  /// The pointer to the application.
  public var pointer: UnsafeMutablePointer<GtkApplication>?
  /// Fields for additional information.