//
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// SerialDisposable.swift
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// RxSwift
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//
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// Created by Krunoslav Zaher on 3/12/15.
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// Copyright © 2015 Krunoslav Zaher. All rights reserved.
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//
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/// Represents a disposable resource whose underlying disposable resource can be replaced by another disposable resource, causing automatic disposal of the previous underlying disposable resource.
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public final class SerialDisposable : DisposeBase, Cancelable {
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private var lock = SpinLock()
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// state
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private var current = nil as Disposable?
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private var disposed = false
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/// - returns: Was resource disposed.
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public var isDisposed: Bool {
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self.disposed
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}
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/// Initializes a new instance of the `SerialDisposable`.
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override public init() {
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super.init()
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}
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/**
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Gets or sets the underlying disposable.
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Assigning this property disposes the previous disposable object.
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If the `SerialDisposable` has already been disposed, assignment to this property causes immediate disposal of the given disposable object.
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*/
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public var disposable: Disposable {
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get {
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self.lock.performLocked {
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self.current ?? Disposables.create()
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}
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}
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set (newDisposable) {
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let disposable: Disposable? = self.lock.performLocked {
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if self.isDisposed {
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return newDisposable
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}
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else {
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let toDispose = self.current
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self.current = newDisposable
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return toDispose
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}
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}
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if let disposable = disposable {
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disposable.dispose()
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}
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}
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}
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/// Disposes the underlying disposable as well as all future replacements.
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public func dispose() {
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self._dispose()?.dispose()
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}
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private func _dispose() -> Disposable? {
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self.lock.performLocked {
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guard !self.isDisposed else { return nil }
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self.disposed = true
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let current = self.current
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self.current = nil
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return current
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}
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}
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}
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