forked from mirrors/linphone-iphone
138 lines
3.3 KiB
Swift
138 lines
3.3 KiB
Swift
/*
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* Copyright (c) 2010-2020 Belledonne Communications SARL.
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*
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* This file is part of linhome
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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import Foundation
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class MutableLiveDataOnChangeClosure<Type>: NSObject {
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let value: (Type?) -> Void
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let onlyOnce: Bool
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init(_ function: @escaping (Type?) -> Void, onlyOnce:Bool = false) {
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value = function
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self.onlyOnce = onlyOnce
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}
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}
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class MutableLiveData<T> {
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private var _value : T? = nil
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private var observers = [MutableLiveDataOnChangeClosure<T>] ()
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private var _opposite : MutableLiveData<Bool>? = nil
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init(_ initial:T) {
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self.value = initial
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}
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init() {
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}
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var value : T? {
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get {
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return self._value
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}
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set {
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self._value = newValue
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self.notifyAllObservers(with: newValue)
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}
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}
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func addObserver(observer: MutableLiveDataOnChangeClosure<T>, andNotifyOnce: Bool = false) {
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observers.append(observer)
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if (andNotifyOnce) {
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notifyValue()
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}
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}
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func removeObserver(observer: MutableLiveDataOnChangeClosure<T>) {
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observers = observers.filter({$0 !== observer})
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}
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func clearObservers() {
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observers.forEach {
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removeObserver(observer: $0)
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}
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}
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func notifyAllObservers(with newValue: T?) {
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for observer in observers {
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observer.value(newValue)
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if (observer.onlyOnce) {
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removeObserver(observer: observer)
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}
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}
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}
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func notifyValue() {
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for observer in observers {
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observer.value(value)
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if (observer.onlyOnce) {
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removeObserver(observer: observer)
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}
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}
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}
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func observe(onChange : @escaping (T?)->Void) {
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let observer = MutableLiveDataOnChangeClosure<T>({ value in
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onChange(value)
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}, onlyOnce: false)
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addObserver(observer: observer)
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}
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func readCurrentAndObserve(onChange : @escaping (T?)->Void) {
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let observer = MutableLiveDataOnChangeClosure<T>({ value in
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onChange(value)
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}, onlyOnce: false)
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addObserver(observer: observer)
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observer.value(value)
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}
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func observeAsUniqueObserver (onChange : @escaping (T?)->Void, unique: Bool = false) {
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let observer = MutableLiveDataOnChangeClosure<T>({ value in
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onChange(value)
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}, onlyOnce: false)
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if (unique) {
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clearObservers()
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}
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addObserver(observer: observer)
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}
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func observeOnce(onChange : @escaping (T?)->Void) {
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let observer = MutableLiveDataOnChangeClosure<T>({ value in
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onChange(value)
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}, onlyOnce: true)
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addObserver(observer: observer)
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}
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func opposite() -> MutableLiveData<Bool>? {
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if (_opposite != nil) {
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return _opposite
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}
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_opposite = MutableLiveData<Bool>(!(value! as! Bool))
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observe { (value) in
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self._opposite!.value = !(value! as! Bool)
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}
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return _opposite
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}
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}
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