Make setup closure in run function sendable

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 6.0
 //
 //  Package.swift
 //  Meta

Sources/Model/Data Flow/Binding.swift

@@ -39,7 +39,7 @@
 /// ```
 @propertyWrapper
 @dynamicMemberLookup
-public struct Binding<Value> {
+public struct Binding<Value>: Sendable where Value: Sendable {
 
     /// The value.
     public var wrappedValue: Value {
@@ -64,11 +64,11 @@ public struct Binding<Value> {
     }
 
     /// The closure for getting the value.
-    private let getValue: () -> Value
+    private let getValue: @Sendable () -> Value
     /// The closure for settings the value.
-    private let setValue: (Value) -> Void
+    private let setValue: @Sendable (Value) -> Void
     /// Handlers observing whether the binding changes.
-    private var handlers: [(Value) -> Void] = []
+    private var handlers: [@Sendable (Value) -> Void] = []
 
     /// Get a property of any content of a `Binding` as a `Binding`.
     /// - Parameter keyPath: The path to the member.
@@ -85,7 +85,7 @@ public struct Binding<Value> {
     /// - Parameters:
     ///   - get: The closure for getting the value.
     ///   - set: The closure for setting the value.
-    public init(get: @escaping () -> Value, set: @escaping (Value) -> Void) {
+    public init(get: @Sendable @escaping () -> Value, set: @Sendable @escaping (Value) -> Void) {
         self.getValue = get
         self.setValue = set
     }
@@ -104,7 +104,7 @@ public struct Binding<Value> {
     /// Observe whether data is changed over this binding.
     /// - Parameter handler: The handler.
     /// - Returns: The binding.
-    public func onSet(_ handler: @escaping (Value) -> Void) -> Self {
+    public func onSet(_ handler: @Sendable @escaping (Value) -> Void) -> Self {
         var newSelf = self
         newSelf.handlers.append(handler)
         return newSelf
@@ -113,7 +113,7 @@ public struct Binding<Value> {
 }
 
 /// Extend bindings.
-extension Binding where Value: MutableCollection {
+extension Binding where Value: MutableCollection, Value.Index: Sendable, Value.Element: Sendable {
 
     /// Get a child at a certain index of the array as a binding.
     /// - Parameters:
@@ -136,7 +136,8 @@ extension Binding where Value: MutableCollection {
 }
 
 /// Extend bindings.
-extension Binding where Value: MutableCollection, Value.Element: Identifiable {
+extension Binding
+where Value: MutableCollection, Value.Element: Identifiable, Value.Index: Sendable, Value.Element: Sendable {
 
     /// Get a child of the array with a certain id as a binding.
     /// - Parameters:

Sources/Model/Data Flow/Model.swift

@@ -58,7 +58,7 @@ public protocol Model {
 }
 
 /// Data about a model's state value.
-public struct ModelData {
+public struct ModelData: Sendable {
 
     /// The state value's identifier.
     var storage: StateContent.Storage
@@ -67,23 +67,8 @@ public struct ModelData {
 
 }
 
-/// Extend the model.
 extension Model {
 
-    /// Get the value as a binding.
-    public var binding: Binding<Self> {
-        .init {
-            getModel()
-        } set: { newValue in
-            guard let data = model else {
-                return
-            }
-            data.storage.value = newValue
-            data.storage.update = true
-            StateManager.updateViews(force: data.force)
-        }
-    }
-
     /// Set the model up.
     ///
     /// At the point this function gets called, the model data is available.
@@ -100,7 +85,9 @@ extension Model {
         setModel(&model)
         data.storage.value = model
         data.storage.update = true
-        StateManager.updateViews(force: data.force)
+        Task {
+            await StateManager.updateViews(force: data.force)
+        }
     }
 
     /// Get the current version of the model.
@@ -116,3 +103,23 @@ extension Model {
     }
 
 }
+
+extension Model where Self: Sendable {
+
+    /// Get the value as a binding.
+    public var binding: Binding<Self> {
+        .init {
+            getModel()
+        } set: { newValue in
+            guard let data = model else {
+                return
+            }
+            data.storage.value = newValue
+            data.storage.update = true
+            Task {
+                await StateManager.updateViews(force: data.force)
+            }
+        }
+    }
+
+}

Sources/Model/Data Flow/Signal.swift

@@ -8,12 +8,14 @@
 import Foundation
 
 /// A type that signalizes an action.
-public struct Signal {
+public struct Signal: Model, Sendable {
 
     /// An action is signalized by toggling a boolean to `true` and back to `false`.
-    @State var boolean = false
+    var boolean = false
     /// A signal has a unique identifier.
     public let id: UUID = .init()
+    /// The model data.
+    public var model: ModelData?
 
     /// Whether the action has caused an update.
     public var update: Bool { boolean }
@@ -23,7 +25,11 @@ public struct Signal {
 
     /// Activate a signal.
     public func signal() {
-        boolean = true
+        setModel { $0.boolean = true }
+    }
+
+    /// Destroy a signal.
+    mutating func destroySignal() {
         boolean = false
     }
 

Sources/Model/Data Flow/State.swift

@@ -9,7 +9,7 @@ import Foundation
 
 /// A property wrapper for properties in a view that should be stored throughout view updates.
 @propertyWrapper
-public struct State<Value>: StateProtocol {
+public struct State<Value>: StateProtocol, Sendable where Value: Sendable {
 
     /// Access the stored value. This updates the views when being changed.
     public var wrappedValue: Value {
@@ -19,7 +19,9 @@ public struct State<Value>: StateProtocol {
         nonmutating set {
             rawValue = newValue
             content.update = true
-            StateManager.updateViews(force: forceUpdates)
+            Task {
+                await StateManager.updateViews(force: forceUpdates)
+            }
         }
     }
 
@@ -49,7 +51,7 @@ public struct State<Value>: StateProtocol {
     var forceUpdates: Bool
 
     /// The closure for initializing the state property's value.
-    var getInitialValue: () -> Value
+    var getInitialValue: @Sendable () -> Value
 
     /// The content.
     let content: StateContent = .init()
@@ -59,7 +61,7 @@ public struct State<Value>: StateProtocol {
     ///     - wrappedValue: The wrapped value.
     ///     - id: An explicit identifier.
     ///     - forceUpdates: Whether to force update all available views when the property gets modified.
-    public init(wrappedValue: @autoclosure @escaping () -> Value, forceUpdates: Bool = false) {
+    public init(wrappedValue: @Sendable @autoclosure @escaping () -> Value, forceUpdates: Bool = false) {
         getInitialValue = wrappedValue
         self.forceUpdates = forceUpdates
     }

Sources/Model/Data Flow/StateContent.swift

@@ -6,7 +6,7 @@
 //
 
 /// A class storing the state's content.
-class StateContent {
+final class StateContent: @unchecked Sendable {
 
     /// The storage.
     var storage: Storage?
@@ -39,7 +39,7 @@ class StateContent {
     init() { }
 
     /// A class storing the value.
-    class Storage {
+    class Storage: @unchecked Sendable {
 
         /// The stored value.
         var value: Any

Sources/Model/Data Flow/StateManager.swift

@@ -8,31 +8,52 @@
 import Foundation
 
 /// This type manages view updates.
-public enum StateManager {
+@globalActor
+public actor StateManager {
 
     /// Whether to block updates in general.
-    public static var blockUpdates = false
+    @StateManager static var blockAllUpdates = false
     /// The application identifier.
     static var appID: String?
     /// The functions handling view updates.
-    static var updateHandlers: [(Bool) -> Void] = []
+    static var updateHandlers: [@Sendable (Bool) async -> Void] = []
+    /// The shared instance of the actor.
+    public static let shared = StateManager()
 
     /// Update all of the views.
     /// - Parameter force: Whether to force all views to update.
     ///
     /// Nothing happens if ``StateManager/blockUpdates`` is true.
-    public static func updateViews(force: Bool = false) {
-        if !blockUpdates {
+    public static func updateViews(force: Bool = false) async {
+        if await !blockAllUpdates {
             for handler in updateHandlers {
-                handler(force)
+                Task {
+                    await handler(force)
+                }
             }
         }
     }
 
     /// Add a handler that is called when the user interface should update.
     /// - Parameter handler: The handler. The parameter defines whether the whole UI should be force updated.
-    static func addUpdateHandler(handler: @escaping (Bool) -> Void) {
+    static func addUpdateHandler(handler: @Sendable @escaping (Bool) async -> Void) {
         updateHandlers.append(handler)
     }
 
+    /// Block all updates.
+    ///
+    /// The user interface will not respond to changes.
+    @StateManager
+    public static func blockUpdates() {
+        blockAllUpdates = true
+    }
+
+    /// Unblock all updates.
+    ///
+    /// The user interface will respond to changes.
+    @StateManager
+    public static func unblockUpdates() {
+        blockAllUpdates = false
+    }
+
 }

Sources/Model/Data Flow/StateProtocol.swift

@@ -8,7 +8,7 @@
 import Foundation
 
 /// An interface for accessing `State` without specifying the generic type.
-protocol StateProtocol {
+protocol StateProtocol: Sendable {
 
     /// The state content.
     var content: StateContent { get }

Sources/Model/Extensions/Array.swift

@@ -44,10 +44,10 @@ extension Array: AnyView where Element == AnyView {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData {
+    ) async where Data: ViewRenderData {
         for (index, element) in filter({ $0.renderable(type: type, data: data) }).enumerated() {
             if let storage = storages[safe: index] {
-                element
+                await element
                     .widget(data: data, type: type)
                     .updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
             }
@@ -62,9 +62,9 @@ extension Array: AnyView where Element == AnyView {
     public func storages<Data>(
         data: WidgetData,
         type: Data.Type
-    ) -> [ViewStorage] where Data: ViewRenderData {
-        compactMap { view in
-            view.renderable(type: type, data: data) ? view.storage(data: data, type: type) : nil
+    ) async -> [ViewStorage] where Data: ViewRenderData {
+        await compactMap { view in
+            await view.renderable(type: type, data: data) ? view.storage(data: data, type: type) : nil
         }
     }
 
@@ -96,6 +96,78 @@ extension Array {
         }
     }
 
+    /// Returns the first element of the sequence that satisfies the given predicate.
+    /// - Parameter predicate: A closure that takes an element of the sequence as its argument
+    /// and returns a Boolean value indicating whether the element is a match.
+    /// - Returns: The first element of the sequence that satisfies `predicate`,
+    /// or `nil` if there is no element that satisfies `predicate`.
+    public func first(where predicate: (Element) async throws -> Bool) async rethrows -> Element? {
+        for element in self {
+            let matches = try await predicate(element)
+            if matches {
+                return element
+            }
+        }
+        return nil
+    }
+
+    /// Returns the index of the first element of the sequence that satisfies the given predicate.
+    /// - Parameter predicate: A closure that takes an element of the sequence as its argument
+    /// and returns a Boolean value indicating whether the element is a match.
+    /// - Returns: The index of the first element of the sequence that satisfies `predicate`,
+    /// or `nil` if there is no element that satisfies `predicate`.
+    public func firstIndex(where predicate: (Element) async throws -> Bool) async rethrows -> Int? {
+        for (index, element) in enumerated() {
+            let matches = try await predicate(element)
+            if matches {
+                return index
+            }
+        }
+        return nil
+    }
+
+    /// Returns the last element of the sequence that satisfies the given predicate.
+    /// - Parameter predicate: A closure that takes an element of the sequence as its argument
+    /// and returns a Boolean value indicating whether the element is a match.
+    /// - Returns: The last element of the sequence that satisfies `predicate`,
+    /// or `nil` if there is no element that satisfies `predicate`.
+    public func last(where predicate: (Element) async throws -> Bool) async rethrows -> Element? {
+        try await reversed().first(where: predicate)
+    }
+
+    /// Returns a Boolean value indicating whether the sequence contains an element that satisfies the given predicate.
+    /// - Parameter predicate: A closure that takes an element of the sequence as its argument
+    /// and returns a Boolean value indicating whether the element is a match.
+    /// - Returns: Whether the sequence contains an element that satisfies `predicate`.
+    public func contains(where predicate: (Element) async throws -> Bool) async rethrows -> Bool {
+        try await first(where: predicate) != nil
+    }
+
+    /// Returns an array containing the results of mapping the given closure over the sequence’s elements.
+    /// Remove elements that are `nil`.
+    /// - Parameter transform: Transforms each element.
+    /// - Returns: The result.
+    public func compactMap<ElementOfResult>(
+        _ transform: (Element) async throws -> ElementOfResult?
+    ) async rethrows -> [ElementOfResult] {
+        var result: [ElementOfResult] = []
+        for element in self {
+            if let element = try await transform(element) {
+                result.append(element)
+            }
+        }
+        return result
+    }
+
+    /// Returns an array containing the results of mapping the given closure over the sequence’s elements.
+    /// - Parameter transform: Transforms each element.
+    /// - Returns: The result.
+    public func map<ElementOfResult>(
+        _ transform: (Element) async throws -> ElementOfResult
+    ) async rethrows -> [ElementOfResult] {
+        try await compactMap { try await transform($0) }
+    }
+
 }
 
 /// Extend arrays.

Sources/Model/Extensions/KeyPath.swift

@@ -0,0 +1,8 @@
+//
+//  KeyPath.swift
+//  Meta
+//
+//  Created by david-swift on 18.09.24.
+//
+
+extension KeyPath: @retroactive @unchecked Sendable { }

Sources/Model/Extensions/OpaquePointer.swift

@@ -0,0 +1,8 @@
+//
+//  OpaquePointer.swift
+//  Meta
+//
+//  Created by david-swift on 29.09.24.
+//
+
+extension OpaquePointer: @retroactive @unchecked Sendable { }

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

@@ -21,7 +21,7 @@
 /// }
 /// ```
 ///
-public protocol App {
+public protocol App: Sendable {
 
     /// The app storage type.
     associatedtype Storage: AppStorage
@@ -60,26 +60,30 @@ extension App {
     public static func setupApp() -> Self {
         var appInstance = self.init()
         appInstance.app = Storage(id: appInstance.id)
-        appInstance.app.storage.app = { appInstance }
-        StateManager.addUpdateHandler { force in
+        StateManager.addUpdateHandler { [appInstance] force in
             let updateProperties = force || appInstance.getState().contains { $0.value.content.update }
             var removeIndices: [Int] = []
-            for (index, element) in appInstance.app.storage.sceneStorage.enumerated() {
-                if element.destroy {
+            for (index, element) in await appInstance.app.storage.sceneStorage.enumerated() {
+                if await element.destroy {
                     removeIndices.insert(index, at: 0)
-                } else if let scene = appInstance.scene.first(
-                    where: { $0.id == element.id }
+                } else if let scene = await appInstance.scene.first(
+                    where: { await $0.id == element.id }
                 ) as? Storage.SceneElementType as? SceneElement {
                     scene.update(element, app: appInstance.app, updateProperties: updateProperties)
                 }
             }
             for index in removeIndices {
-                appInstance.app.storage.sceneStorage.remove(at: index)
+                await appInstance.app.modifyStandardAppStorage { $0.sceneStorage.remove(at: index) }
             }
         }
         StateManager.appID = appInstance.id
-        let state = appInstance.getState()
-        appInstance.app.storage.stateStorage = state
+        Task { [appInstance] in
+            let state = appInstance.getState()
+            await appInstance.app.modifyStandardAppStorage { storage in
+                storage.stateStorage = state
+                storage.app = { appInstance }
+            }
+        }
         return appInstance
     }
 

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

@@ -6,7 +6,7 @@
 //
 
 /// The app storage protocol.
-public protocol AppStorage: AnyObject {
+public protocol AppStorage: Actor, Sendable {
 
     /// The type of scene elements (which should be backend-specific).
     associatedtype SceneElementType
@@ -20,10 +20,28 @@ public protocol AppStorage: AnyObject {
 
     /// Run the application.
     /// - Parameter setup: A closure that is expected to be executed right at the beginning.
-    func run(setup: @escaping () -> Void)
+    nonisolated func run(setup: @Sendable @escaping () -> Void)
 
     /// Terminate the application.
-    func quit()
+    nonisolated func quit()
+
+}
+
+extension AppStorage {
+
+    /// Modify the app storage.
+    /// - Parameter modify: The modifications.
+    func modifyStandardAppStorage(_ modify: (inout StandardAppStorage) -> Void) {
+        var copy = storage
+        modify(&copy)
+        self.storage = copy
+    }
+
+    /// Append a scene.
+    /// - Parameter scene: The scene.
+    public func appendScene(_ scene: SceneStorage) {
+        modifyStandardAppStorage { $0.sceneStorage.append(scene) }
+    }
 
 }
 
@@ -32,13 +50,28 @@ extension AppStorage {
 
     /// Focus the scene element with a certain id (if supported). Create the element if it doesn't already exist.
     /// - Parameter id: The element's id.
-    public func showSceneElement(_ id: String) {
-        storage.sceneStorage.last { $0.id == id && !$0.destroy }?.show() ?? addSceneElement(id)
+    nonisolated public func showSceneElement(_ id: String) {
+        Task {
+            await storage.sceneStorage
+                .last { scene in
+                    let destroy = await scene.destroy
+                    return await scene.id == id && !destroy
+                }?
+                .show() ?? addSceneElement(id)
+        }
     }
 
     /// Add a new scene element with the content of the scene element with a certain id.
     /// - Parameter id: The element's id.
-    public func addSceneElement(_ id: String) {
+    nonisolated public func addSceneElement(_ id: String) {
+        Task {
+            await internalAddSceneElement(id)
+        }
+    }
+
+    /// Add a new scene element with the content of the scene element with a certain id.
+    /// - Parameter id: The element's id.
+    func internalAddSceneElement(_ id: String) {
         if let element = storage.app?().scene.last(where: { $0.id == id }) {
             let container = element.container(app: self)
             storage.sceneStorage.append(container)
@@ -48,13 +81,13 @@ extension AppStorage {
 
     /// Focus the window with a certain id (if supported). Create the window if it doesn't already exist.
     /// - Parameter id: The window's id.
-    public func showWindow(_ id: String) {
+    nonisolated public func showWindow(_ id: String) {
         showSceneElement(id)
     }
 
     /// Add a new window with the content of the window template with a certain id.
     /// - Parameter id: The window template's id.
-    public func addWindow(_ id: String) {
+    nonisolated public func addWindow(_ id: String) {
         addSceneElement(id)
     }
 

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

@@ -6,7 +6,7 @@
 //
 
 /// The app storage protocol.
-public struct StandardAppStorage {
+public struct StandardAppStorage: Sendable {
 
     /// The scene storage.
     public var sceneStorage: [SceneStorage] = []
@@ -15,7 +15,7 @@ public struct StandardAppStorage {
     var stateStorage: [String: StateProtocol] = [:]
 
     /// The scene.
-    var app: (() -> any App)?
+    var app: (@Sendable () -> any App)?
 
     /// Initialize the standard app storage.
     public init() { }

Sources/Model/User Interface/Scene/SceneElement.swift

@@ -6,7 +6,7 @@
 //
 
 /// A structure conforming to `SceneElement` can be added to an app's `scene` property.
-public protocol SceneElement {
+public protocol SceneElement: Sendable {
 
     /// The window type's identifier.
     var id: String { get }

Sources/Model/User Interface/Scene/SceneStorage.swift

@@ -6,22 +6,22 @@
 //
 
 /// Store a reference to a rendered scene element in a view storage.
-public class SceneStorage {
+public actor SceneStorage {
 
     /// The scene element's identifier.
     public var id: String
     /// The pointer.
     ///
     /// It can be a C pointer, a Swift class, or other information depending on the backend.
-    public var pointer: Any?
+    public var pointer: Sendable?
     /// The scene element's view content.
-    public var content: [String: [ViewStorage]]
+    var content: [String: [ViewStorage]]
     /// Various properties of a scene element.
-    public var fields: [String: Any] = [:]
+    var fields: [String: Sendable] = [:]
     /// Whether the reference to the window should disappear in the next update.
     public var destroy = false
     /// Show the scene element (including moving into the foreground, if possible).
-    public var show: () -> Void
+    public var show: @Sendable () -> Void
     /// The previous state of the scene element.
     public var previousState: SceneElement?
 
@@ -43,9 +43,9 @@ public class SceneStorage {
     ///   - show: Function called when the scene element should be displayed.
     public init(
         id: String,
-        pointer: Any?,
+        pointer: Sendable?,
         content: [String: [ViewStorage]] = [:],
-        show: @escaping () -> Void
+        show: @Sendable @escaping () -> Void
     ) {
         self.id = id
         self.pointer = pointer
@@ -53,4 +53,65 @@ public class SceneStorage {
         self.show = show
     }
 
+    /// Set the pointer.
+    /// - Parameter value: The new pointer.
+    public func setPointer(_ value: Sendable?) {
+        pointer = value
+    }
+
+    /// Set the element of a certain field.
+    /// - Parameters:
+    ///     - key: The key.
+    ///     - value: The field.
+    public func setField(key: String, value: Sendable) {
+        fields[key] = value
+    }
+
+    /// Remove a certain field.
+    /// - Parameters:
+    ///     - key: The key.
+    public func removeField(key: String) {
+        fields.removeValue(forKey: key)
+    }
+
+    /// Get the element of a certain field.
+    /// - Parameter key: The key.
+    /// - Returns: The field.
+    public func getField(key: String) -> Sendable? {
+        fields[key]
+    }
+
+    /// Set the content elements under a certain key.
+    /// - Parameters:
+    ///     - key: The key.
+    ///     - value: The content elements.
+    public func setContent(key: String, value: [ViewStorage]) {
+        content[key] = value
+    }
+
+    /// Get the content elements under a certain key.
+    /// - Parameter key: The key.
+    /// - Returns: The content elements.
+    public func getContent(key: String) -> [ViewStorage] {
+        content[key] ?? []
+    }
+
+    /// Set the previous state.
+    /// - Parameter state: The state.
+    public func setPreviousState(_ state: SceneElement?) {
+        previousState = state
+    }
+
+    /// Set whether the scene will be destroyed.
+    /// - Parameter destroy: Whether the scene will be destroyed.
+    public func setDestroy(_ destroy: Bool) {
+        self.destroy = destroy
+    }
+
+    /// Set the closure which shows the scene.
+    /// - Parameter show: The closure.
+    public func setShow(_ show: @Sendable @escaping () -> Void) {
+        self.show = show
+    }
+
 }

Sources/Model/User Interface/View/AnyView.swift

@@ -6,7 +6,7 @@
 //
 
 /// The view type used for any form of a view.
-public protocol AnyView {
+public protocol AnyView: Sendable {
 
     /// The view's content.
     @ViewBuilder var viewContent: Body { get }
@@ -38,8 +38,8 @@ extension AnyView {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData {
-        widget(data: data, type: type)
+    ) async where Data: ViewRenderData {
+        await widget(data: data, type: type)
             .update(storage, data: data, updateProperties: updateProperties, type: type)
     }
 
@@ -51,8 +51,8 @@ extension AnyView {
     public func storage<Data>(
         data: WidgetData,
         type: Data.Type
-    ) -> ViewStorage where Data: ViewRenderData {
-        widget(data: data, type: type).container(data: data, type: type)
+    ) async -> ViewStorage where Data: ViewRenderData {
+        await widget(data: data, type: type).container(data: data, type: type)
     }
 
     /// Wrap the view into a widget.

Sources/Model/User Interface/View/Properties/BindingProperty.swift

@@ -10,14 +10,14 @@
 /// This will be used if you do not provide a custom ``Widget/update(_:data:updateProperties:type:)`` method
 /// or call the ``Widget/updateProperties(_:updateProperties:)`` method in your custom update method.
 @propertyWrapper
-public struct BindingProperty<Value, Pointer>: BindingPropertyProtocol {
+public struct BindingProperty<Value, Pointer>: BindingPropertyProtocol where Value: Sendable {
 
     /// The wrapped binding.
     public var wrappedValue: Binding<Value>
     /// Observe the UI element.
-    var observe: (Pointer, Binding<Value>, ViewStorage) -> Void
+    var observe: @Sendable (Pointer, Binding<Value>, ViewStorage) async -> Void
     /// Set the UI element's property.
-    var setValue: (Pointer, Value, ViewStorage) -> Void
+    var setValue: @Sendable (Pointer, Value, ViewStorage) async -> Void
 
     /// Initialize a property.
     /// - Parameters:
@@ -27,8 +27,8 @@ public struct BindingProperty<Value, Pointer>: BindingPropertyProtocol {
     ///     - pointer: The type of the pointer.
     public init(
         wrappedValue: Binding<Value>,
-        observe: @escaping (Pointer, Binding<Value>, ViewStorage) -> Void,
-        set setValue: @escaping (Pointer, Value, ViewStorage) -> Void,
+        observe: @Sendable @escaping (Pointer, Binding<Value>, ViewStorage) async -> Void,
+        set setValue: @Sendable @escaping (Pointer, Value, ViewStorage) async -> Void,
         pointer: Pointer.Type
     ) {
         self.wrappedValue = wrappedValue
@@ -44,14 +44,14 @@ public struct BindingProperty<Value, Pointer>: BindingPropertyProtocol {
     ///     - pointer: The type of the pointer.
     public init(
         wrappedValue: Binding<Value>,
-        observe: @escaping (Pointer, Binding<Value>) -> Void,
-        set setValue: @escaping (Pointer, Value) -> Void,
+        observe: @Sendable @escaping (Pointer, Binding<Value>) async -> Void,
+        set setValue: @Sendable @escaping (Pointer, Value) async -> Void,
         pointer: Pointer.Type
     ) {
         self.init(
             wrappedValue: wrappedValue,
-            observe: { pointer, value, _ in observe(pointer, value) },
-            set: { pointer, value, _ in setValue(pointer, value) },
+            observe: { pointer, value, _ in await observe(pointer, value) },
+            set: { pointer, value, _ in await setValue(pointer, value) },
             pointer: pointer
         )
     }
@@ -59,19 +59,19 @@ public struct BindingProperty<Value, Pointer>: BindingPropertyProtocol {
 }
 
 /// The binding property protocol.
-protocol BindingPropertyProtocol {
+protocol BindingPropertyProtocol: Sendable {
 
     /// The binding's wrapped value.
-    associatedtype Value
+    associatedtype Value: Sendable
     /// The storage's pointer.
     associatedtype Pointer
 
     /// The wrapped value.
     var wrappedValue: Binding<Value> { get }
     /// Observe the property.
-    var observe: (Pointer, Binding<Value>, ViewStorage) -> Void { get }
+    var observe: @Sendable (Pointer, Binding<Value>, ViewStorage) async -> Void { get }
     /// Set the property.
-    var setValue: (Pointer, Value, ViewStorage) -> Void { get }
+    var setValue: @Sendable (Pointer, Value, ViewStorage) async -> Void { get }
 
 }
 
@@ -84,12 +84,12 @@ extension Widget {
     func setBindingProperty<Property>(
         property: Property,
         storage: ViewStorage
-    ) where Property: BindingPropertyProtocol {
+    ) async where Property: BindingPropertyProtocol {
         if let optional = property.wrappedValue.wrappedValue as? any OptionalProtocol, optional.optionalValue == nil {
             return
         }
-        if let pointer = storage.pointer as? Property.Pointer {
-            property.setValue(pointer, property.wrappedValue.wrappedValue, storage)
+        if let pointer = await storage.pointer as? Property.Pointer {
+            await property.setValue(pointer, property.wrappedValue.wrappedValue, storage)
         }
     }
 

Sources/Model/User Interface/View/Properties/Property.swift

@@ -10,10 +10,10 @@
 /// This will be used if you do not provide a custom ``Widget/update(_:data:updateProperties:type:)`` method
 /// or call the ``Widget/updateProperties(_:updateProperties:)`` method in your custom update method.
 @propertyWrapper
-public struct Property<Value, Pointer>: PropertyProtocol {
+public struct Property<Value, Pointer>: PropertyProtocol where Value: Sendable {
 
     /// The function applying the property to the UI.
-    public var setProperty: (Pointer, Value, ViewStorage) -> Void
+    public var setProperty: @Sendable (Pointer, Value, ViewStorage) async -> Void
     /// The wrapped value.
     public var wrappedValue: Value
     /// The update strategy.
@@ -27,7 +27,7 @@ public struct Property<Value, Pointer>: PropertyProtocol {
     ///     - updateStrategy: The update strategy, this should be ``UpdateStrategy/automatic`` in most cases.
     public init(
         wrappedValue: Value,
-        set setProperty: @escaping (Pointer, Value, ViewStorage) -> Void,
+        set setProperty: @Sendable @escaping (Pointer, Value, ViewStorage) async -> Void,
         pointer: Pointer.Type,
         updateStrategy: UpdateStrategy = .automatic
     ) {
@@ -44,13 +44,13 @@ public struct Property<Value, Pointer>: PropertyProtocol {
     ///     - updateStrategy: The update strategy, this should be ``UpdateStrategy/automatic`` in most cases.
     public init(
         wrappedValue: Value,
-        set setProperty: @escaping (Pointer, Value) -> Void,
+        set setProperty: @Sendable @escaping (Pointer, Value) async -> Void,
         pointer: Pointer.Type,
         updateStrategy: UpdateStrategy = .automatic
     ) {
         self.init(
             wrappedValue: wrappedValue,
-            set: { pointer, value, _ in setProperty(pointer, value) },
+            set: { pointer, value, _ in await setProperty(pointer, value) },
             pointer: pointer,
             updateStrategy: updateStrategy
         )
@@ -66,13 +66,13 @@ extension Property where Value: OptionalProtocol {
     ///     - pointer: The type of the pointer.
     ///     - updateStrategy: The update strategy, this should be ``UpdateStrategy/automatic`` in most cases.
     public init(
-        set setProperty: @escaping (Pointer, Value.Wrapped, ViewStorage) -> Void,
+        set setProperty: @Sendable @escaping (Pointer, Value.Wrapped, ViewStorage) async -> Void,
         pointer: Pointer.Type,
         updateStrategy: UpdateStrategy = .automatic
     ) {
         self.setProperty = { pointer, value, storage in
             if let value = value.optionalValue {
-                setProperty(pointer, value, storage)
+                await setProperty(pointer, value, storage)
             }
         }
         wrappedValue = nil
@@ -86,12 +86,12 @@ extension Property where Value: OptionalProtocol {
     ///     - pointer: The type of the pointer.
     ///     - updateStrategy: The update strategy, this should be ``UpdateStrategy/automatic`` in most cases.
     public init(
-        set setProperty: @escaping (Pointer, Value.Wrapped) -> Void,
+        set setProperty: @Sendable @escaping (Pointer, Value.Wrapped) async -> Void,
         pointer: Pointer.Type,
         updateStrategy: UpdateStrategy = .automatic
     ) {
         self.init(
-            set: { pointer, value, _ in setProperty(pointer, value) },
+            set: { pointer, value, _ in await setProperty(pointer, value) },
             pointer: pointer,
             updateStrategy: updateStrategy
         )
@@ -100,7 +100,7 @@ extension Property where Value: OptionalProtocol {
 }
 
 /// The property protocol.
-protocol PropertyProtocol {
+protocol PropertyProtocol: Sendable {
 
     /// The type of the wrapped value.
     associatedtype Value
@@ -110,14 +110,14 @@ protocol PropertyProtocol {
     /// The wrapped value.
     var wrappedValue: Value { get }
     /// Set the property.
-    var setProperty: (Pointer, Value, ViewStorage) -> Void { get }
+    var setProperty: @Sendable (Pointer, Value, ViewStorage) async -> Void { get }
     /// The update strategy.
     var updateStrategy: UpdateStrategy { get }
 
 }
 
 /// The update strategy for properties.
-public enum UpdateStrategy {
+public enum UpdateStrategy: Sendable {
 
     /// If equatable, update only when the value changed.
     /// If not equatable, this is equivalent to ``UpdateStrategy/always``.
@@ -140,10 +140,10 @@ extension Widget {
     public func container<Data>(
         data: WidgetData,
         type: Data.Type
-    ) -> ViewStorage where Data: ViewRenderData {
+    ) async -> ViewStorage where Data: ViewRenderData {
         let storage = ViewStorage(initializeWidget())
-        initProperties(storage, data: data, type: type)
-        update(storage, data: data, updateProperties: true, type: type)
+        await initProperties(storage, data: data, type: type)
+        await update(storage, data: data, updateProperties: true, type: type)
         return storage
     }
 
@@ -160,10 +160,10 @@ extension Widget {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData {
-        self.updateProperties(storage, data: data, updateProperties: updateProperties, type: type)
+    ) async where Data: ViewRenderData {
+        await self.updateProperties(storage, data: data, updateProperties: updateProperties, type: type)
         if updateProperties {
-            storage.previousState = self
+            await storage.setPreviousState(self)
         }
     }
 
@@ -176,16 +176,16 @@ extension Widget {
         _ storage: ViewStorage,
         data: WidgetData,
         type: Data.Type
-    ) where Data: ViewRenderData {
+    ) async where Data: ViewRenderData {
         let mirror = Mirror(reflecting: self)
         for property in mirror.children {
             if let value = property.value as? any ViewPropertyProtocol {
-                let subview = value.wrappedValue.storage(data: data, type: type)
-                initViewProperty(value, view: subview, parent: storage)
-                storage.content[property.label ?? .mainContent] = [subview]
+                let subview = await value.wrappedValue.storage(data: data, type: type)
+                await initViewProperty(value, view: subview, parent: storage)
+                await storage.setContent(key: property.label ?? .mainContent, value: [subview])
             }
             if let value = property.value as? any BindingPropertyProtocol {
-                initBindingProperty(value, parent: storage)
+                await initBindingProperty(value, parent: storage)
             }
         }
     }
@@ -199,9 +199,10 @@ extension Widget {
         _ value: Property,
         view: ViewStorage,
         parent: ViewStorage
-    ) where Property: ViewPropertyProtocol {
-        if let view = view.pointer as? Property.ViewPointer, let pointer = parent.pointer as? Property.Pointer {
-            value.setView(pointer, view)
+    ) async where Property: ViewPropertyProtocol {
+        if let view = await view.pointer as? Property.ViewPointer,
+           let pointer = await parent.pointer as? Property.Pointer {
+            await value.setView(pointer, view)
         }
     }
 
@@ -209,9 +210,12 @@ extension Widget {
     /// - Parameters:
     ///     - value: The property.
     ///     - parent: The view storage.
-    func initBindingProperty<Property>(_ value: Property, parent: ViewStorage) where Property: BindingPropertyProtocol {
-        if let view = parent.pointer as? Property.Pointer {
-            value.observe(
+    func initBindingProperty<Property>(
+        _ value: Property,
+        parent: ViewStorage
+    ) async where Property: BindingPropertyProtocol {
+        if let view = await parent.pointer as? Property.Pointer {
+            await value.observe(
                 view,
                 .init {
                     value.wrappedValue.wrappedValue
@@ -237,14 +241,20 @@ extension Widget {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData {
+    ) async where Data: ViewRenderData {
         let mirror = Mirror(reflecting: self)
-        updateNotEquatable(mirror: mirror, storage: storage, data: data, updateProperties: updateProperties, type: type)
+        await updateNotEquatable(
+            mirror: mirror,
+            storage: storage,
+            data: data,
+            updateProperties: updateProperties,
+            type: type
+        )
         guard updateProperties else {
             return
         }
-        updateAlwaysWhenStateUpdate(mirror: mirror, storage: storage)
-        updateEquatable(mirror: mirror, storage: storage)
+        await updateAlwaysWhenStateUpdate(mirror: mirror, storage: storage)
+        await updateEquatable(mirror: mirror, storage: storage)
     }
 
     /// Update the properties which are not equatable and should always be updated (e.g. closures).
@@ -260,20 +270,21 @@ extension Widget {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData {
+    ) async where Data: ViewRenderData {
         for property in mirror.children {
             if let value = property.value as? any PropertyProtocol {
                 if value.updateStrategy == .always ||
                 value.wrappedValue as? any Equatable == nil && value.updateStrategy != .alwaysWhenStateUpdate {
-                    setProperty(property: value, storage: storage)
+                    await setProperty(property: value, storage: storage)
                 }
             }
             if let value = property.value as? any ViewPropertyProtocol,
-               let storage = storage.content[property.label ?? .mainContent]?.first {
-               value.wrappedValue.updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
+                let storage = await storage.getContent(key: property.label ?? .mainContent).first {
+                await value.wrappedValue
+                    .updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
             }
             if let value = property.value as? any BindingPropertyProtocol {
-                setBindingProperty(property: value, storage: storage)
+                await setBindingProperty(property: value, storage: storage)
             }
         }
     }
@@ -285,11 +296,11 @@ extension Widget {
     ///     - storage: The view storage.
     ///
     /// Initialize the ``Property`` property wrapper with the ``UpdateStrategy/alwaysWhenStateUpdate``.
-    func updateAlwaysWhenStateUpdate(mirror: Mirror, storage: ViewStorage) {
+    func updateAlwaysWhenStateUpdate(mirror: Mirror, storage: ViewStorage) async {
         for property in mirror.children {
             if let value = property.value as? any PropertyProtocol {
                 if value.updateStrategy == .alwaysWhenStateUpdate {
-                    setProperty(property: value, storage: storage)
+                    await setProperty(property: value, storage: storage)
                 }
             }
         }
@@ -299,8 +310,8 @@ extension Widget {
     /// - Parameters:
     ///     - mirror: A mirror of the widget.
     ///     - storage: The view storage.
-    func updateEquatable(mirror: Mirror, storage: ViewStorage) {
-        let previousState: Mirror.Children? = if let previousState = storage.previousState {
+    func updateEquatable(mirror: Mirror, storage: ViewStorage) async {
+        let previousState: Mirror.Children? = if let previousState = await storage.previousState {
             Mirror(reflecting: previousState).children
         } else {
             nil
@@ -317,7 +328,7 @@ extension Widget {
                     update = false
                 }
                 if update {
-                    setProperty(property: value, storage: storage)
+                    await setProperty(property: value, storage: storage)
                 }
             }
         }
@@ -354,12 +365,12 @@ extension Widget {
     /// - Parameters:
     ///     - property: The property.
     ///     - storage: The view storage.
-    func setProperty<Property>(property: Property, storage: ViewStorage) where Property: PropertyProtocol {
+    func setProperty<Property>(property: Property, storage: ViewStorage) async where Property: PropertyProtocol {
         if let optional = property.wrappedValue as? any OptionalProtocol, optional.optionalValue == nil {
             return
         }
-        if let pointer = storage.pointer as? Property.Pointer {
-            property.setProperty(pointer, property.wrappedValue, storage)
+        if let pointer = await storage.pointer as? Property.Pointer {
+            await property.setProperty(pointer, property.wrappedValue, storage)
         }
     }
 

Sources/Model/User Interface/View/Properties/ViewProperty.swift

@@ -15,7 +15,7 @@ public struct ViewProperty<Pointer, ViewPointer>: ViewPropertyProtocol {
     /// The wrapped value.
     public var wrappedValue: Body = []
     /// Set the view.
-    var setView: (Pointer, ViewPointer) -> Void
+    var setView: @Sendable (Pointer, ViewPointer) async -> Void
 
     /// Initialize a property.
     /// - Parameters:
@@ -23,7 +23,7 @@ public struct ViewProperty<Pointer, ViewPointer>: ViewPropertyProtocol {
     ///     - pointer: The pointer type of the parent view (usually a concrete view type).
     ///     - subview: The pointer type of the child view (usually a protocol, view class, or similar).
     public init(
-        set setView: @escaping (Pointer, ViewPointer) -> Void,
+        set setView: @Sendable @escaping (Pointer, ViewPointer) async -> Void,
         pointer: Pointer.Type,
         subview: ViewPointer.Type
     ) {
@@ -35,7 +35,7 @@ public struct ViewProperty<Pointer, ViewPointer>: ViewPropertyProtocol {
 /// The view property protocol.
 ///
 /// Do not use for wrapper widgets.
-protocol ViewPropertyProtocol {
+protocol ViewPropertyProtocol: Sendable {
 
     /// The type of the view's pointer.
     associatedtype Pointer
@@ -45,6 +45,6 @@ protocol ViewPropertyProtocol {
     /// The wrapped value.
     var wrappedValue: Body { get }
     /// Set the view.
-    var setView: (Pointer, ViewPointer) -> Void { get }
+    var setView: @Sendable (Pointer, ViewPointer) async -> Void { get }
 
 }

Sources/Model/User Interface/View/ViewStorage.swift

@@ -6,18 +6,18 @@
 //
 
 /// Store a reference to a rendered view in a view storage.
-public class ViewStorage {
+public actor ViewStorage: Sendable {
 
     /// The pointer.
     ///
     /// It can be a C pointer, a Swift class, or other information depending on the backend.
-    public var pointer: Any?
+    public var pointer: Sendable?
     /// The view's content for container widgets.
-    public var content: [String: [ViewStorage]]
+    var content: [String: [ViewStorage]]
     /// The view's state (used in `StateWrapper`).
     var state: [String: StateProtocol] = [:]
     /// Various properties of a widget.
-    public var fields: [String: Any] = [:]
+    var fields: [String: Sendable] = [:]
     /// The previous state of the widget.
     public var previousState: Widget?
 
@@ -36,7 +36,7 @@ public class ViewStorage {
     ///   - pointer: The pointer to the widget, its type depends on the backend.
     ///   - content: The view's content for container widgets.
     public init(
-        _ pointer: Any?,
+        _ pointer: Sendable?,
         content: [String: [ViewStorage]] = [:],
         state: Widget? = nil
     ) {
@@ -45,4 +45,88 @@ public class ViewStorage {
         self.previousState = state
     }
 
+    /// Initialize a view storage.
+    /// - Parameters:
+    ///   - pointer: The opaque pointer.
+    ///   - content: The view's content for container widgets.
+    public init(
+        _ pointer: OpaquePointer?,
+        content: [String: [ViewStorage]] = [:],
+        state: Widget? = nil
+    ) {
+        self.pointer = pointer
+        self.content = content
+        self.previousState = state
+    }
+
+    /// Set the state under a certain key.
+    /// - Parameters:
+    ///     - key: The key.
+    ///     - value: The state.
+    func setState(key: String, value: StateProtocol) {
+        state[key] = value
+    }
+
+    /// Set the state.
+    /// - Parameter state: The state.
+    func setState(_ state: [String: StateProtocol]) {
+        self.state = state
+    }
+
+    /// Get the state under a certain key.
+    /// - Parameter key: The key.
+    /// - Returns: The state.
+    func getState(key: String) -> StateProtocol? {
+        state[key]
+    }
+
+    /// Set the pointer.
+    /// - Parameter value: The new pointer.
+    public func setPointer(_ value: Sendable?) {
+        pointer = value
+    }
+
+    /// Set the element of a certain field.
+    /// - Parameters:
+    ///     - key: The key.
+    ///     - value: The field.
+    public func setField(key: String, value: Sendable) {
+        fields[key] = value
+    }
+
+    /// Remove a certain field.
+    /// - Parameters:
+    ///     - key: The key.
+    public func removeField(key: String) {
+        fields.removeValue(forKey: key)
+    }
+
+    /// Get the element of a certain field.
+    /// - Parameter key: The key.
+    /// - Returns: The field.
+    public func getField(key: String) -> Sendable? {
+        fields[key]
+    }
+
+    /// Set the content elements under a certain key.
+    /// - Parameters:
+    ///     - key: The key.
+    ///     - value: The content elements.
+    public func setContent(key: String, value: [ViewStorage]) {
+        content[key] = value
+    }
+
+    /// Get the content elements under a certain key.
+    /// - Parameter key: The key.
+    /// - Returns: The content elements.
+    public func getContent(key: String) -> [ViewStorage] {
+        content[key] ?? []
+    }
+
+    /// Set the previous state.
+    /// - Parameter state: The state.
+    public func setPreviousState(_ state: Widget?) {
+        previousState = state
+    }
+
 }

Sources/Model/User Interface/View/Widget.swift

@@ -19,7 +19,7 @@ public protocol Widget: AnyView {
     func container<Data>(
         data: WidgetData,
         type: Data.Type
-    ) -> ViewStorage where Data: ViewRenderData
+    ) async -> ViewStorage where Data: ViewRenderData
 
     /// Update the stored content.
     /// - Parameters:
@@ -32,14 +32,14 @@ public protocol Widget: AnyView {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData
+    ) async where Data: ViewRenderData
 
     /// Get the widget.
     /// - Returns: The widget.
     ///
     /// Define this function only if you do not define ``Widget/container(data:type:)``.
     /// Otherwise, it will not have an effect.
-    func initializeWidget() -> Any
+    func initializeWidget() -> Sendable
 
 }
 
@@ -51,7 +51,7 @@ extension Widget {
 
     /// Print a warning if the widget does not set this function but it gets accessed.
     /// - Returns: A dummy pointer.
-    public func initializeWidget() -> Any {
+    public func initializeWidget() -> Sendable {
         print("Warning: Define initialize widget function or container function for \(Self.self)")
         return ""
     }

Sources/Model/User Interface/View/WidgetData.swift

@@ -6,16 +6,16 @@
 //
 
 /// Data passed to widgets when initializing or updating the container.
-public struct WidgetData {
+public struct WidgetData: Sendable {
 
     /// The view modifiers.
-    public var modifiers: [(AnyView) -> AnyView] = []
+    public var modifiers: [@Sendable (AnyView) -> AnyView] = []
     /// The scene storage of the parent scene element.
     public var sceneStorage: SceneStorage
     /// The app storage of the parent app.
     public var appStorage: any AppStorage
     /// Fields for custom data.
-    public var fields: [String: Any] = [:]
+    public var fields: [String: Sendable] = [:]
 
     /// Modify the data so that there are no modifiers.
     public var noModifiers: Self {

Sources/View/AppearObserver.swift

@@ -9,7 +9,7 @@
 struct AppearObserver: ConvenienceWidget {
 
     /// The custom code to edit the widget.
-    var modify: (ViewStorage) -> Void
+    var modify: @Sendable (ViewStorage) async -> Void
     /// The wrapped view.
     var content: AnyView
 
@@ -21,9 +21,9 @@ struct AppearObserver: ConvenienceWidget {
     func container<Data>(
         data: WidgetData,
         type: Data.Type
-    ) -> ViewStorage where Data: ViewRenderData {
-        let storage = content.storage(data: data, type: type)
-        modify(storage)
+    ) async -> ViewStorage where Data: ViewRenderData {
+        let storage = await content.storage(data: data, type: type)
+        await modify(storage)
         return storage
     }
 
@@ -38,8 +38,8 @@ struct AppearObserver: ConvenienceWidget {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData {
-        content.updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
+    ) async where Data: ViewRenderData {
+        await content.updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
     }
 
 }
@@ -50,15 +50,15 @@ extension AnyView {
     /// Run a function on the widget when it appears for the first time.
     /// - Parameter closure: The function.
     /// - Returns: A view.
-    public func inspectOnAppear(_ closure: @escaping (ViewStorage) -> Void) -> AnyView {
+    public func inspectOnAppear(_ closure: @Sendable @escaping (ViewStorage) async -> Void) -> AnyView {
         AppearObserver(modify: closure, content: self)
     }
 
     /// Run a function when the view appears for the first time.
     /// - Parameter closure: The function.
     /// - Returns: A view.
-    public func onAppear(_ closure: @escaping () -> Void) -> AnyView {
-        inspectOnAppear { _ in closure() }
+    public func onAppear(_ closure: @Sendable @escaping () async -> Void) -> AnyView {
+        inspectOnAppear { _ in await closure() }
     }
 
 }

Sources/View/ContentModifier.swift

@@ -11,7 +11,7 @@ struct ContentModifier<Content>: ConvenienceWidget where Content: AnyView {
     /// The wrapped view.
     var content: AnyView
     /// The closure for the modification.
-    var modify: (Content) -> AnyView
+    var modify: @Sendable (Content) -> AnyView
 
     /// The view storage.
     /// - Parameters:
@@ -21,8 +21,8 @@ struct ContentModifier<Content>: ConvenienceWidget where Content: AnyView {
     func container<Data>(
         data: WidgetData,
         type: Data.Type
-    ) -> ViewStorage where Data: ViewRenderData {
-        content.storage(data: data.modify { $0.modifiers += [modifyView] }, type: type)
+    ) async -> ViewStorage where Data: ViewRenderData {
+        await content.storage(data: data.modify { $0.modifiers += [modifyView] }, type: type)
     }
 
     /// Update the stored content.
@@ -36,8 +36,8 @@ struct ContentModifier<Content>: ConvenienceWidget where Content: AnyView {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData {
-        content
+    ) async where Data: ViewRenderData {
+        await content
             .updateStorage(
                 storage,
                 data: data.modify { $0.modifiers += [modifyView] },
@@ -68,7 +68,7 @@ extension AnyView {
     /// - Returns: A view.
     public func modifyContent<Content>(
         _ type: Content.Type,
-        modify: @escaping (Content) -> AnyView
+        modify: @Sendable @escaping (Content) -> AnyView
     ) -> AnyView where Content: AnyView {
         ContentModifier(content: self, modify: modify)
     }

Sources/View/DummyEitherView.swift

@@ -23,9 +23,9 @@ struct DummyEitherView: ConvenienceWidget {
     func container<Data>(
         data: WidgetData,
         type: Data.Type
-    ) -> ViewStorage where Data: ViewRenderData {
+    ) async -> ViewStorage where Data: ViewRenderData {
         let content = type.EitherViewType(condition) { view1 ?? [] } else: { view2 ?? [] }
-        let storage = content.storage(data: data, type: type)
+        let storage = await content.storage(data: data, type: type)
         return storage
     }
 
@@ -40,9 +40,9 @@ struct DummyEitherView: ConvenienceWidget {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData {
+    ) async where Data: ViewRenderData {
         let content = type.EitherViewType(condition) { view1 ?? [] } else: { view2 ?? [] }
-        content.updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
+        await content.updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
     }
 
 }

Sources/View/Freeze.swift

@@ -21,8 +21,8 @@ struct Freeze: ConvenienceWidget {
     func container<Data>(
         data: WidgetData,
         type: Data.Type
-    ) -> ViewStorage where Data: ViewRenderData {
-        content.storage(data: data, type: type)
+    ) async -> ViewStorage where Data: ViewRenderData {
+        await content.storage(data: data, type: type)
     }
 
     /// Update the stored content.
@@ -36,11 +36,11 @@ struct Freeze: ConvenienceWidget {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData {
+    ) async where Data: ViewRenderData {
         guard !freeze else {
             return
         }
-        content.updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
+        await content.updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
     }
 
 }

Sources/View/InspectorWrapper.swift

@@ -9,7 +9,7 @@
 struct InspectorWrapper: ConvenienceWidget {
 
     /// The custom code to edit the widget.
-    var modify: (ViewStorage, Bool) -> Void
+    var modify: @Sendable (ViewStorage, Bool) async -> Void
     /// The wrapped view.
     var content: AnyView
 
@@ -21,9 +21,9 @@ struct InspectorWrapper: ConvenienceWidget {
     func container<Data>(
         data: WidgetData,
         type: Data.Type
-    ) -> ViewStorage where Data: ViewRenderData {
-        let storage = content.storage(data: data, type: type)
-        modify(storage, true)
+    ) async -> ViewStorage where Data: ViewRenderData {
+        let storage = await content.storage(data: data, type: type)
+        await modify(storage, true)
         return storage
     }
 
@@ -38,9 +38,9 @@ struct InspectorWrapper: ConvenienceWidget {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData {
-        content.updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
-        modify(storage, updateProperties)
+    ) async where Data: ViewRenderData {
+        await content.updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
+        await modify(storage, updateProperties)
     }
 
 }
@@ -51,15 +51,15 @@ extension AnyView {
     /// Run a custom code accessing the view's storage when initializing and updating the view.
     /// - Parameter modify: Modify the storage. The boolean indicates whether state in parent views changed.
     /// - Returns: A view.
-    public func inspect(_ modify: @escaping (ViewStorage, Bool) -> Void) -> AnyView {
+    public func inspect(_ modify: @Sendable @escaping (ViewStorage, Bool) async -> Void) -> AnyView {
         InspectorWrapper(modify: modify, content: self)
     }
 
     /// Run a function when the view gets updated.
     /// - Parameter onUpdate: The function.
     /// - Returns: A view.
-    public func onUpdate(_ onUpdate: @escaping () -> Void) -> AnyView {
-        inspect { _, _ in onUpdate() }
+    public func onUpdate(_ onUpdate: @Sendable @escaping () async -> Void) -> AnyView {
+        inspect { _, _ in await onUpdate() }
     }
 
 }

Sources/View/ModifierStopper.swift

@@ -19,8 +19,8 @@ struct ModifierStopper: ConvenienceWidget {
     func container<Data>(
         data: WidgetData,
         type: Data.Type
-    ) -> ViewStorage where Data: ViewRenderData {
-        content.storage(data: data.noModifiers, type: type)
+    ) async -> ViewStorage where Data: ViewRenderData {
+        await content.storage(data: data.noModifiers, type: type)
     }
 
     /// Update the stored content.
@@ -34,8 +34,8 @@ struct ModifierStopper: ConvenienceWidget {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData {
-        content.updateStorage(storage, data: data.noModifiers, updateProperties: updateProperties, type: type)
+    ) async where Data: ViewRenderData {
+        await content.updateStorage(storage, data: data.noModifiers, updateProperties: updateProperties, type: type)
     }
 
 }

Sources/View/StateWrapper.swift

@@ -9,13 +9,13 @@
 struct StateWrapper: ConvenienceWidget {
 
     /// The content.
-    var content: () -> Body
+    var content: @Sendable () -> Body
     /// The state information (from properties with the `State` wrapper).
     var state: [String: StateProtocol] = [:]
 
     /// Initialize a `StateWrapper`.
     /// - Parameter content: The view content.
-    init(@ViewBuilder content: @escaping () -> Body) {
+    init(@ViewBuilder content: @Sendable @escaping () -> Body) {
         self.content = content
     }
 
@@ -23,7 +23,7 @@ struct StateWrapper: ConvenienceWidget {
     /// - Parameters:
     ///   - content: The view content.
     ///   - state: The state information.
-    init(content: @escaping () -> Body, state: [String: StateProtocol]) {
+    init(content: @Sendable @escaping () -> Body, state: [String: StateProtocol]) {
         self.content = content
         self.state = state
     }
@@ -40,10 +40,10 @@ struct StateWrapper: ConvenienceWidget {
         data: WidgetData,
         updateProperties: Bool,
         type: Data.Type
-    ) where Data: ViewRenderData {
+    ) async where Data: ViewRenderData {
         var updateProperties = updateProperties
         for property in state {
-            if let storage = storage.state[property.key]?.content.storage {
+            if let storage = await storage.getState(key: property.key)?.content.storage {
                 property.value.content.storage = storage
             }
             if property.value.content.update {
@@ -51,10 +51,16 @@ struct StateWrapper: ConvenienceWidget {
                 property.value.content.update = false
             }
         }
-        guard let storage = storage.content[.mainContent]?.first else {
+        guard let storage = await storage.getContent(key: .mainContent).first else {
             return
         }
-        content().updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
+        await content().updateStorage(storage, data: data, updateProperties: updateProperties, type: type)
+        for property in state {
+            if var value = property.value.content.value as? Signal, value.update {
+                value.destroySignal()
+                property.value.content.value = value
+            }
+        }
     }
 
     /// Get a view storage.
@@ -65,10 +71,10 @@ struct StateWrapper: ConvenienceWidget {
     func container<Data>(
         data: WidgetData,
         type: Data.Type
-    ) -> ViewStorage where Data: ViewRenderData {
-        let content = content().storage(data: data, type: type)
-        let storage = ViewStorage(content.pointer, content: [.mainContent: [content]])
-        storage.state = state
+    ) async -> ViewStorage where Data: ViewRenderData {
+        let content = await content().storage(data: data, type: type)
+        let storage = ViewStorage(await content.pointer, content: [.mainContent: [content]])
+        await storage.setState(state)
         for element in state {
             element.value.setup()
         }

Tests/DemoApp/DemoApp.swift

@@ -1,5 +1,5 @@
 import Foundation
-@testable import Meta
+import Meta
 import SampleBackends
 
 @main
@@ -73,7 +73,7 @@ struct TestView: View {
 
 }
 
-struct TestModel: Model {
+struct TestModel: Sendable, Model {
 
     var test = "Label"
 

Tests/SampleBackends/Backend1.swift

@@ -6,16 +6,16 @@ public enum Backend1 {
 
         public init() { }
 
-        public func container<Data>(data: WidgetData, type: Data.Type) -> ViewStorage where Data: ViewRenderData {
+        public func container<Data>(data: WidgetData, type: Data.Type) async -> ViewStorage where Data: ViewRenderData {
             print("Init test widget 1")
             let storage = ViewStorage(nil)
-            storage.fields["test"] = 0
+            await storage.setField(key: "test", value: 0)
             return storage
         }
 
-        public func update<Data>(_ storage: ViewStorage, data: WidgetData, updateProperties: Bool, type: Data.Type) {
-            print("Update test widget 1 (#\(storage.fields["test"] ?? ""))")
-            storage.fields["test"] = (storage.fields["test"] as? Int ?? 0) + 1
+        public func update<Data>(_ storage: ViewStorage, data: WidgetData, updateProperties: Bool, type: Data.Type) async {
+            print("Update test widget 1 (#\(await storage.getField(key: "test") ?? ""))")
+            await storage.setField(key: "test", value: (storage.getField(key: "test") as? Int ?? 0) + 1)
         }
 
     }
@@ -24,16 +24,16 @@ public enum Backend1 {
 
         public init() { }
 
-        public func container<Data>(data: WidgetData, type: Data.Type) -> ViewStorage where Data: ViewRenderData {
+        public func container<Data>(data: WidgetData, type: Data.Type) async -> ViewStorage where Data: ViewRenderData {
             print("Init test widget 3")
             let storage = ViewStorage(nil)
-            storage.fields["test"] = 0
+            await storage.setField(key: "test", value: 0)
             return storage
         }
 
-        public func update<Data>(_ storage: ViewStorage, data: WidgetData, updateProperties: Bool, type: Data.Type) {
-            print("Update test widget 3 (#\(storage.fields["test"] ?? ""))")
-            storage.fields["test"] = (storage.fields["test"] as? Int ?? 0) + 1
+        public func update<Data>(_ storage: ViewStorage, data: WidgetData, updateProperties: Bool, type: Data.Type) async {
+            print("Update test widget 3 (#\(await storage.getField(key: "test") ?? ""))")
+            await storage.setField(key: "test", value: (storage.getField(key: "test") as? Int ?? 0) + 1)
         }
 
     }
@@ -42,28 +42,28 @@ public enum Backend1 {
 
         @Property(set: { print("Update button (label = \($1))") }, pointer: Any.self)
         var label = ""
-        @Property(set: { $2.fields["action"] = $1 }, pointer: Any.self)
-        var action: () -> Void = { }
+        @Property(set: { $2.setField(key: "action", value: $1) }, pointer: Any.self)
+        var action: @Sendable () -> Void = { }
 
-        public init(_ label: String, action: @escaping () -> Void) {
+        public init(_ label: String, action: @Sendable @escaping () -> Void) {
             self.label = label
             self.action = action
         }
-        public func container<Data>(data: WidgetData, type: Data.Type) -> ViewStorage where Data: ViewRenderData {
+        public func container<Data>(data: WidgetData, type: Data.Type) async -> ViewStorage where Data: ViewRenderData {
             print("Init button")
             let storage = ViewStorage(nil)
             Task {
                 try await Task.sleep(nanoseconds: 1_000_000_000)
-                (storage.fields["action"] as? () -> Void)?()
+                (await storage.getField(key: "action") as? @Sendable () -> Void)?()
             }
-            storage.fields["action"] = action
-            storage.previousState = self
+            await storage.setField(key: "action", value: action)
+            await storage.setPreviousState(self)
             return storage
         }
 
     }
 
-    public struct Window: BackendSceneElement {
+    public struct Window: BackendSceneElement, Sendable {
 
         public var id: String
         var spawn: Int
@@ -77,7 +77,9 @@ public enum Backend1 {
 
         public func setupInitialContainers<Storage>(app: Storage) where Storage: AppStorage {
             for _ in 0..<spawn {
-                app.storage.sceneStorage.append(container(app: app))
+                Task {
+                    await app.appendScene(container(app: app))
+                }
             }
         }
 
@@ -86,17 +88,21 @@ public enum Backend1 {
             let storage = SceneStorage(id: id, pointer: nil) {
                 print("Make visible")
             }
-            let viewStorage = content.storage(data: .init(sceneStorage: storage, appStorage: app), type: MainViewRenderData.self)
-            storage.content[.mainContent] = [viewStorage]
+            Task {
+                let viewStorage = await content.storage(data: .init(sceneStorage: storage, appStorage: app), type: MainViewRenderData.self)
+                await storage.setContent(key: .mainContent, value: [viewStorage])
+            }
             return storage
         }
 
         public func update<Storage>(_ storage: SceneStorage, app: Storage, updateProperties: Bool) where Storage: AppStorage {
-            print("Update \(id)")
-            guard let viewStorage = storage.content[.mainContent]?.first else {
-                return
+            Task {
+                print("Update \(id)")
+                guard let viewStorage = await storage.getContent(key: .mainContent).first else {
+                    return
+                }
+                await content.updateStorage(viewStorage, data: .init(sceneStorage: storage, appStorage: app), updateProperties: updateProperties, type: MainViewRenderData.self)
             }
-            content.updateStorage(viewStorage, data: .init(sceneStorage: storage, appStorage: app), updateProperties: updateProperties, type: MainViewRenderData.self)
         }
 
     }
@@ -109,17 +115,15 @@ public enum Backend1 {
             self.content = content()
         }
 
-        public func container<Data>(data: WidgetData, type: Data.Type) -> Meta.ViewStorage where Data: ViewRenderData {
+        public func container<Data>(data: WidgetData, type: Data.Type) async -> Meta.ViewStorage where Data: ViewRenderData {
             let storage = ViewStorage(nil)
-            storage.content = [.mainContent: content.storages(data: data, type: type)]
+            await storage.setContent(key: .mainContent, value: content.storages(data: data, type: type))
             return storage
         }
 
-        public func update<Data>(_ storage: Meta.ViewStorage, data: WidgetData, updateProperties: Bool, type: Data.Type) where Data: ViewRenderData {
-            guard let storages = storage.content[.mainContent] else {
-                return
-            }
-            content.update(storages, data: data, updateProperties: updateProperties, type: type)
+        public func update<Data>(_ storage: Meta.ViewStorage, data: WidgetData, updateProperties: Bool, type: Data.Type) async where Data: ViewRenderData {
+            let storages = await storage.getContent(key: .mainContent)
+            await content.update(storages, data: data, updateProperties: updateProperties, type: type)
         }
 
     }
@@ -150,19 +154,19 @@ public enum Backend1 {
 
     public protocol BackendSceneElement: SceneElement { }
 
-    public class Backend1App: AppStorage {
+    public actor Backend1App: AppStorage {
 
         public typealias SceneElementType = BackendSceneElement
 
         public var storage: StandardAppStorage = .init()
 
-        public required init(id: String) { }
+        public init(id: String) { }
 
-        public func run(setup: @escaping () -> Void) {
+        nonisolated public func run(setup: @escaping () -> Void) {
             setup()
         }
 
-        public func quit() {
+        nonisolated public func quit() {
             fatalError("Quit")
         }
 

Tests/SampleBackends/Backend2.swift

@@ -6,16 +6,16 @@ public enum Backend2 {
     
         public init() { }
     
-        public func container<Data>(data: WidgetData, type: Data.Type) -> ViewStorage where Data: ViewRenderData {
+        public func container<Data>(data: WidgetData, type: Data.Type) async -> ViewStorage where Data: ViewRenderData {
             print("Init test widget 2")
             let storage = ViewStorage(nil)
-            storage.fields["test"] = 0
+            await storage.setField(key: "test", value: 0)
             return storage
         }
 
-        public func update<Data>(_ storage: ViewStorage, data: WidgetData, updateProperties: Bool, type: Data.Type) {
-            print("Update test widget 2 (#\(storage.fields["test"] ?? ""))")
-            storage.fields["test"] = (storage.fields["test"] as? Int ?? 0) + 1
+        public func update<Data>(_ storage: ViewStorage, data: WidgetData, updateProperties: Bool, type: Data.Type) async {
+            print("Update test widget 2 (#\(await storage.getField(key: "test") ?? ""))")
+            await storage.setField(key: "test", value: (storage.getField(key: "test") as? Int ?? 0) + 1)
         }
     
     }
@@ -24,16 +24,16 @@ public enum Backend2 {
 
         public init() { }
 
-        public func container<Data>(data: WidgetData, type: Data.Type) -> ViewStorage where Data: ViewRenderData {
+        public func container<Data>(data: WidgetData, type: Data.Type) async -> ViewStorage where Data: ViewRenderData {
             print("Init test widget 4")
             let storage = ViewStorage(nil)
-            storage.fields["test"] = 0
+            await storage.setField(key: "test", value: 0)
             return storage
         }
 
-        public func update<Data>(_ storage: ViewStorage, data: WidgetData, updateProperties: Bool, type: Data.Type) {
-            print("Update test widget 4 (#\(storage.fields["test"] ?? ""))")
-            storage.fields["test"] = (storage.fields["test"] as? Int ?? 0) + 1
+        public func update<Data>(_ storage: ViewStorage, data: WidgetData, updateProperties: Bool, type: Data.Type) async {
+            print("Update test widget 4 (#\(await storage.getField(key: "test") ?? ""))")
+            await storage.setField(key: "test", value: (storage.getField(key: "test") as? Int ?? 0) + 1)
         }
 
     }
@@ -46,17 +46,15 @@ public enum Backend2 {
             self.content = content()
         }
 
-        public func container<Data>(data: WidgetData, type: Data.Type) -> Meta.ViewStorage where Data: ViewRenderData {
+        public func container<Data>(data: WidgetData, type: Data.Type) async -> Meta.ViewStorage where Data: ViewRenderData {
             let storage = ViewStorage(nil)
-            storage.content = [.mainContent: content.storages(data: data, type: type)]
+            await storage.setContent(key: .mainContent, value: content.storages(data: data, type: type))
             return storage
         }
 
-        public func update<Data>(_ storage: Meta.ViewStorage, data: WidgetData, updateProperties: Bool, type: Data.Type) where Data: ViewRenderData {
-            guard let storages = storage.content[.mainContent] else {
-                return
-            }
-            content.update(storages, data: data, updateProperties: updateProperties, type: type)
+        public func update<Data>(_ storage: Meta.ViewStorage, data: WidgetData, updateProperties: Bool, type: Data.Type) async where Data: ViewRenderData {
+            let storages = await storage.getContent(key: .mainContent)
+            await content.update(storages, data: data, updateProperties: updateProperties, type: type)
         }
 
     }
@@ -65,19 +63,19 @@ public enum Backend2 {
 
     public protocol BackendSceneElement: SceneElement { }
 
-    public class Backend2App: AppStorage {
+    public actor Backend2App: AppStorage{
 
         public typealias SceneElementType = BackendSceneElement
 
         public var storage: StandardAppStorage = .init()
 
-        public required init(id: String) { }
+        public init(id: String) { }
 
-        public func run(setup: @escaping () -> Void) {
+        nonisolated public func run(setup: @escaping () -> Void) {
             setup()
         }
 
-        public func quit() {
+        nonisolated public func quit() {
             fatalError("Quit")
         }