64 lines
2.1 KiB
Swift
64 lines
2.1 KiB
Swift
/*
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The MIT License (MIT)
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Copyright (c) 2015-present Badoo Trading Limited.
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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*/
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import Foundation
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// Be aware this is not thread safe!
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// Why class? https://lists.swift.org/pipermail/swift-users/Week-of-Mon-20160711/002580.html
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public class Observable<T> {
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public init(_ value: T) {
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self.value = value
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}
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public var value: T {
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didSet {
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self.cleanDeadObservers()
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for observer in self.observers {
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observer.closure(oldValue, self.value)
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}
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}
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}
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public func observe(_ observer: AnyObject, closure: @escaping (_ old: T, _ new: T) -> ()) {
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self.observers.append(Observer(owner: observer, closure: closure))
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self.cleanDeadObservers()
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}
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private func cleanDeadObservers() {
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self.observers = self.observers.filter { $0.owner != nil }
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}
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private lazy var observers = [Observer<T>]()
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}
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private struct Observer<T> {
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weak var owner: AnyObject?
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let closure: (_ old: T, _ new: T) -> ()
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init (owner: AnyObject, closure: @escaping (_ old: T, _ new: T) -> ()) {
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self.owner = owner
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self.closure = closure
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}
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}
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