88 lines
2.6 KiB
Swift
88 lines
2.6 KiB
Swift
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//
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// Observers.swift
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// TUICallKit
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//
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// Created by vincepzhang on 2023/4/3.
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//
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import Foundation
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class Observer {}
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public class Observable<Type> {
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// MARK: - Callback
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fileprivate class Callback {
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fileprivate weak var observer: AnyObject?
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fileprivate let options: [ObservableOptions]
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fileprivate let closure: (Type, ObservableOptions) -> Void
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fileprivate init(
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observer: AnyObject,
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options: [ObservableOptions],
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closure: @escaping (Type, ObservableOptions) -> Void) {
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self.observer = observer
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self.options = options
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self.closure = closure
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}
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}
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// MARK: - Properties Use Swift's didSet feature to call back the value to the callback
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public var value: Type {
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didSet {
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removeNilObserverCallbacks()
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notifyCallbacks(value: oldValue, option: .old)
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notifyCallbacks(value: value, option: .new)
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}
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}
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private func removeNilObserverCallbacks() {
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callbacks = callbacks.filter { $0.observer != nil }
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}
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// MARK: Callback to callback to implement closure callback
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private func notifyCallbacks(value: Type, option: ObservableOptions) {
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let callbacksToNotify = callbacks.filter { $0.options.contains(option) }
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callbacksToNotify.forEach { $0.closure(value, option) }
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}
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// MARK: - Object Lifecycle
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public init(_ value: Type) {
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self.value = value
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}
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// MARK: - Managing Observers
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private var callbacks: [Callback] = []
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public func addObserver(
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_ observer: AnyObject,
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removeIfExists: Bool = true,
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options: [ObservableOptions] = [.new],
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closure: @escaping (Type, ObservableOptions) -> Void) {
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if removeIfExists {
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removeObserver(observer)
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}
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let callback = Callback(observer: observer, options: options, closure: closure)
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callbacks.append(callback)
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if options.contains(.initial) {
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closure(value, .initial)
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}
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}
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public func removeObserver(_ observer: AnyObject) {
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callbacks = callbacks.filter { $0.observer !== observer }
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}
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}
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// MARK: - ObservableOptions
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public struct ObservableOptions: OptionSet {
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public static let initial = ObservableOptions(rawValue: 1 << 0)
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public static let old = ObservableOptions(rawValue: 1 << 1)
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public static let new = ObservableOptions(rawValue: 1 << 2)
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public var rawValue: Int
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public init(rawValue: Int) {
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self.rawValue = rawValue
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}
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}
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