128 lines
4.0 KiB
Swift
128 lines
4.0 KiB
Swift
//
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// State.swift
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// Meta
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//
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// Created by david-swift on 26.05.24.
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//
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import Foundation
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/// A property wrapper for properties in a view that should be stored throughout view updates.
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@propertyWrapper
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public struct State<Value>: StateProtocol {
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/// Access the stored value. This updates the views when being changed.
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public var wrappedValue: Value {
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get {
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rawValue
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}
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nonmutating set {
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rawValue = newValue
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if !blockUpdates {
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content.update = true
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StateManager.updateViews(force: forceUpdates)
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}
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writeValue?(newValue)
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}
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}
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/// Get the value as a binding using the `$` prefix.
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public var projectedValue: Binding<Value> {
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.init {
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wrappedValue
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} set: { newValue in
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self.wrappedValue = newValue
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}
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}
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/// Get and set the value without updating the views.
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public var rawValue: Value {
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get {
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guard let value = content.value as? Value else {
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return initialValue()
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}
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return value
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}
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nonmutating set {
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content.value = newValue
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}
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}
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/// Whether to force update the views when the value changes.
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var forceUpdates = false
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/// Whether to block updates.
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var blockUpdates = false
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/// The closure for initializing the state property's value.
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var getInitialValue: () -> Value
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/// Perform additional operations when the value changes.
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var writeValue: ((Value) -> Void)?
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/// The content.
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let content: StateContent = .init()
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/// Initialize a property representing a state in the view with an autoclosure.
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/// - Parameters:
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/// - wrappedValue: The wrapped value.
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/// - forceUpdates: Whether to force update all available views when the property gets modified.
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public init(wrappedValue: @autoclosure @escaping () -> Value, forceUpdates: Bool = false) {
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getInitialValue = wrappedValue
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self.forceUpdates = forceUpdates
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}
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/// Initialize a property representing a state in the view with an autoclosure.
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/// - Parameters:
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/// - wrappedValue: The wrapped value.
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/// - blockUpdates: Whether updates to this state value should not update the UI.
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///
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/// This can be useful for storing data and reading this data on special occasions, e.g. on startup.
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public init(wrappedValue: @autoclosure @escaping () -> Value, blockUpdates: Bool) {
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getInitialValue = wrappedValue
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self.blockUpdates = blockUpdates
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}
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/// Initialize a property representing a state in the view with an explicit closure.
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/// - Parameters:
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/// - wrappedValue: Get the wrapped value.
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/// - writeValue: Perform additional operations when the value changes.
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/// - forceUpdates: Whether to force update all available views when the property gets modified.
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/// - blockUpdates: Whether updates to this state value should not update the UI.
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///
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/// This initializer can be used e.g. to get data from the disk.
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public init(
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wrappedValue: @escaping () -> Value,
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writeValue: ((Value) -> Void)? = nil,
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forceUpdates: Bool = false,
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blockUpdates: Bool = false
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) {
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getInitialValue = wrappedValue
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self.writeValue = writeValue
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self.forceUpdates = forceUpdates
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self.blockUpdates = blockUpdates
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}
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/// Get the initial value.
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/// - Returns: The initial value.
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func initialValue() -> Value {
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let initialValue = getInitialValue()
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let storage = StateContent.Storage(value: initialValue)
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if var model = initialValue as? Model {
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model.model = .init(storage: storage, force: forceUpdates)
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model.setup()
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content.storage = storage
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content.value = model
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} else {
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content.storage = storage
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}
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return initialValue
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}
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/// Set the storage up.
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func setup() {
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_ = initialValue()
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}
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}
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