65 lines
1.5 KiB
Swift
65 lines
1.5 KiB
Swift
//
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// Copyright 2021 Signal Messenger, LLC
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// SPDX-License-Identifier: AGPL-3.0-only
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//
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import Foundation
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// A thread-safe timer that runs on a specific queue and which
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// can be safely created, invalidated or deallocated on any thread.
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public class OffMainThreadTimer {
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private let timeInterval: TimeInterval
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private let repeats: Bool
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private let queue: DispatchQueue
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public typealias Block = (OffMainThreadTimer) -> Void
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private let block: Block
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private let _isValid = AtomicBool(true, lock: .sharedGlobal)
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public var isValid: Bool {
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get { _isValid.get() }
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set { _isValid.set(newValue) }
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}
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public init(timeInterval: TimeInterval,
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repeats: Bool,
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queue: DispatchQueue = .global(),
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_ block: @escaping Block) {
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owsAssertDebug(timeInterval > 0)
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self.timeInterval = max(0, timeInterval)
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self.repeats = repeats
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self.queue = queue
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self.block = block
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scheduleNextFire()
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}
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private func scheduleNextFire() {
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queue.asyncAfter(deadline: .now() + timeInterval) { [weak self] in
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self?.fire()
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}
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}
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private func fire() {
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assertOnQueue(queue)
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guard self.isValid else {
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return
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}
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block(self)
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guard repeats else {
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invalidate()
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return
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}
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scheduleNextFire()
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}
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deinit {
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invalidate()
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}
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public func invalidate() {
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isValid = false
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}
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}
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