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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
import Foundation
open class CancellableDeferred<T>: Deferred<T> {
public var dispatchWorkItem: DispatchWorkItem?
internal var _running = false
internal var _cancelled = false
open func cancel() {
objc_sync_enter(self)
defer { objc_sync_exit(self) }
let queue = OperationQueue.current?.underlyingQueue
queue?.suspend()
defer { queue?.resume() }
dispatchWorkItem?.cancel()
_cancelled = true
}
open var cancelled: Bool {
objc_sync_enter(self)
defer { objc_sync_exit(self) }
return _cancelled
}
open var running: Bool {
get {
objc_sync_enter(self)
defer { objc_sync_exit(self) }
return _running
}
set {
objc_sync_enter(self)
defer { objc_sync_exit(self) }
_running = newValue
}
}
override open func fill(_ value: T) {
defer {
dispatchWorkItem = nil
}
guard !cancelled else { return }
super.fill(value)
}
}