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我有单例类
class DeviceController:NSObject, CocoaMQTTDelegate {
static let sharedInstance = DeviceController()
var deviceOnArray:[String] = []
var deviceOffArray:[String] = []
private override init() {
clientID = "xyz-" + String(ProcessInfo().processIdentifier)
mqtt = CocoaMQTT(clientID: clientID, host: "device_controller.xyz.net", port: 1883)
mqtt.username = "username"
mqtt.password = "password"
mqtt.willMessage = CocoaMQTTWill(topic: "/will", message: "dieout")
mqtt.keepAlive = 30
mqtt.cleanSession = true
DeviceController.isConnecting = true
super.init()
mqtt.delegate = self
mqtt.connect()
self.registerBackgroundTask()
}
func sendArm(topic:String){
// add device to deviceOnArray
}
func sendDisarm(topic:String){
// remove device from deviceOnArray if exist here if I check by code that device is in array it returns false but on console if print it contains the device, It only heppens when I call sendArm and sendDisarm with a second.
let lockQueue = DispatchQueue(label: "com.test.LockQueue")
lockQueue.sync() {
// all code now inside this
}
// I also used above code but it's not working
}
}
如果你阅读代码,你就会知道我在从 deviceOnArray/deviceOffArray 读取正确值时遇到问题,我不确定如何解释这个问题,但我认为我需要的是 Obj-C 原子线程安全多变的。知道如何创建一个吗?
最佳答案
import Foundation
class AtomicValue<T> {
private var _value: T
private var accessQueue: DispatchQueue!
init (value: T) {
_value = value
let address = Unmanaged.passUnretained(self).toOpaque()
let label = "accessQueue.\(type(of: self)).\(address)"
accessQueue = DispatchQueue(label: label)
}
}
// MARK: Get/Set with synchronization in current queue
extension AtomicValue {
func waitSet(lockValueAccessWhile closure: ((_ currentValue: T) -> T)?) {
accessQueue.sync { [weak self] in
guard let self = self, let value = closure?(self._value) else { return }
self._value = value
}
}
func waitGet(lockValueAccessWhile closure: ((_ currentValue: T) -> Void)?) {
accessQueue.sync { [weak self] in
guard let self = self else { return }
closure?(self._value)
}
}
func waitUpdate(lockValueAccessWhile closure: ((_ currentValue: inout T) -> Void)?) {
accessQueue.sync { [weak self] in
guard let self = self else { return }
closure?(&self._value)
}
}
func waitMap<V>(lockValueAccessWhile closure: ((_ currentValue: T) -> V)?) -> NotQueueSafeValue<V> {
var value: V!
waitGet { value = closure?($0) }
return NotQueueSafeValue(notQueueSafeValue: value)
}
// Be careful with func waitGet() -> NotQueueSafeValue<T>. It is ONLY for WRITE (SAVE).
// BAD CODE: atomicValue.waitGet().notQueueSafeValue.doSometing().
// it is possible that atomicValue._value could be changed while func doSometing() is performing
// GOOD CODE: atomicValue.waitGet { $0.doSometing() }.
// atomicValue._value will never changed while func doSometing() is performing
struct NotQueueSafeValue<T> { let notQueueSafeValue: T }
func waitGet() -> NotQueueSafeValue<T> {
var value: T!
waitGet { value = $0 }
return NotQueueSafeValue(notQueueSafeValue: value)
}
func waitSet(value: T) { waitSet { _ in return value } }
}
// MARK: Get/Set in current queue
extension AtomicValue {
func set(waitAccessIn queue: DispatchQueue, closure: ((_ currentValue: T) -> T)?) {
queue.async { [weak self] in self?.waitSet(lockValueAccessWhile: closure) }
}
func get(waitAccessIn queue: DispatchQueue, closure: ((_ currentValue: T) -> Void)?) {
queue.async { [weak self] in self?.waitGet(lockValueAccessWhile: closure) }
}
func update(waitAccessIn queue: DispatchQueue, closure: ((_ currentValue: inout T) -> Void)?) {
queue.async { [weak self] in self?.waitUpdate(lockValueAccessWhile: closure) }
}
}
// Usage
let atomicValue = AtomicValue(value: 0)
atomicValue.waitSet { currentValue -> Int in
// Multiple sequential (sync) actions
return currentValue + 1
}
atomicValue.waitGet { currentValue in
// Multiple sequential (sync) actions
print("\(currentValue)")
}
atomicValue.waitUpdate { currentValue in
// Multiple sequential (sync) actions
currentValue += 1
}
atomicValue.set(waitAccessIn: .global(qos: .default)) { currentValue -> Int in
// Multiple sequential (sync) actions
return currentValue + 1
}
atomicValue.get(waitAccessIn: .global(qos: .default)) { currentValue in
// Multiple sequential (sync) actions
print("\(currentValue)")
}
atomicValue.update(waitAccessIn: .global(qos: .background)) { currentValue in
// Multiple sequential (sync) actions
currentValue += 1
}
print(atomicValue.waitGet().notQueueSafeValue)
atomicValue.waitSet(value: 2)
print("\(atomicValue.waitMap { "value: \($0)" }.notQueueSafeValue )")
Do not forget to paste the solution code here.
class Test {
private let atomicValue = AtomicValue(value: 0)
private(set) var count = 0
private var usecDelay: UInt32 = 1000
private let range = (0..<100)
private func _set(currentValue: Int, dispatchGroup: DispatchGroup? = nil) -> Int {
let newValue = currentValue + 1
//print("\(queue.label) queue: \(newValue)")
count += 1
usleep(usecDelay)
dispatchGroup?.leave()
return newValue
}
private func _get(value: Int, queueLabel: String, dispatchGroup: DispatchGroup? = nil) {
print(" get \(queueLabel) queue: \(value)")
usleep(usecDelay)
dispatchGroup?.leave()
}
func test1(queue: DispatchQueue, completion: (() -> Void)?) {
queue.async { [weak self] in
guard let self = self else { return }
self.range.forEach { _ in
self.atomicValue.waitSet { [weak self] in
return self?._set(currentValue: $0) ?? $0
}
self.atomicValue.waitGet { [weak self] in
self?._get(value: $0, queueLabel: queue.label)
}
}
print("test1.work at \(queue.label) queue completed")
completion?()
}
}
func test2(queue: DispatchQueue, completion: (() -> Void)?) {
let dispatchGroup = DispatchGroup()
range.forEach { _ in
dispatchGroup.enter()
dispatchGroup.enter()
}
queue.async { [weak self] in
guard let self = self else { return }
self.range.forEach { _ in
self.atomicValue.waitUpdate { [weak self] in
guard let value = self?._set(currentValue: $0, dispatchGroup: dispatchGroup) else { return }
$0 = value
}
self.atomicValue.waitGet { [weak self] in
self?._get(value: $0, queueLabel: queue.label, dispatchGroup: dispatchGroup)
}
}
}
dispatchGroup.notify(queue: queue) {
print("test2.work at \(queue.label) queue completed")
completion?()
}
}
func test3(queue: DispatchQueue, waitIn waitQueue: DispatchQueue, completion: (() -> Void)?) {
let dispatchGroup = DispatchGroup()
range.forEach { _ in
dispatchGroup.enter()
dispatchGroup.enter()
dispatchGroup.enter()
}
queue.async { [weak self] in
guard let self = self else { return }
self.range.forEach { _ in
self.atomicValue.set(waitAccessIn: waitQueue) { [weak self] in
return self?._set(currentValue: $0, dispatchGroup: dispatchGroup) ?? $0
}
self.atomicValue.get(waitAccessIn: waitQueue) { [weak self] in
self?._get(value: $0, queueLabel: queue.label, dispatchGroup: dispatchGroup)
}
self.atomicValue.update(waitAccessIn: waitQueue) { [weak self] in
guard let value = self?._set(currentValue: $0, dispatchGroup: dispatchGroup) else { return }
$0 = value
}
}
}
dispatchGroup.notify(queue: queue) {
print("test3.work at \(queue.label) queue completed")
completion?()
}
}
func run() {
let dspatchGroup = DispatchGroup()
dspatchGroup.enter()
test1(queue: .global(qos: .utility)) { dspatchGroup.leave() } // result: count += range.max()
dspatchGroup.enter()
test1(queue: .global(qos: .unspecified)) { dspatchGroup.leave() } // result: count += range.max()
dspatchGroup.enter()
test2(queue: .main) { dspatchGroup.leave() } // result: count += range.max()
dspatchGroup.enter()
test2(queue: .global(qos: .unspecified)) { dspatchGroup.leave() } // result: count += range.max()
dspatchGroup.enter()
test3(queue: .global(qos: .default), waitIn: .global(qos: .background)) { dspatchGroup.leave() } // result: count += 2*range.max()
dspatchGroup.enter()
test3(queue: .main, waitIn: .global(qos: .userInteractive)) { dspatchGroup.leave() } // result: count += 2*range.max()
dspatchGroup.notify(queue: .main) { print("End. Count: \(self.count)") }
}
}
Test().run()
get com.apple.root.default-qos queue: 3
get com.apple.root.default-qos queue: 4
get com.apple.root.default-qos queue: 4
get com.apple.root.utility-qos queue: 5
get com.apple.root.default-qos queue: 6
get com.apple.root.default-qos queue: 7
get com.apple.root.default-qos queue: 8
get com.apple.root.default-qos queue: 9
get com.apple.root.default-qos queue: 10
get com.apple.root.default-qos queue: 11
get com.apple.root.default-qos queue: 12
get com.apple.root.default-qos queue: 13
get com.apple.root.default-qos queue: 14
test3.work at com.apple.root.default-qos queue completed
get com.apple.main-thread queue: 15
get com.apple.root.default-qos queue: 17
get com.apple.root.default-qos queue: 18
get com.apple.root.utility-qos queue: 18
get com.apple.main-thread queue: 19
get com.apple.root.default-qos queue: 21
get com.apple.root.default-qos queue: 22
get com.apple.root.utility-qos queue: 22
get com.apple.main-thread queue: 23
get com.apple.root.default-qos queue: 25
get com.apple.root.default-qos queue: 26
get com.apple.root.utility-qos queue: 26
get com.apple.main-thread queue: 27
get com.apple.root.default-qos queue: 29
get com.apple.root.default-qos queue: 30
get com.apple.root.utility-qos queue: 30
get com.apple.main-thread queue: 31
get com.apple.root.default-qos queue: 33
get com.apple.root.default-qos queue: 34
get com.apple.root.utility-qos queue: 34
get com.apple.main-thread queue: 35
get com.apple.root.default-qos queue: 37
get com.apple.root.default-qos queue: 38
get com.apple.root.utility-qos queue: 38
get com.apple.main-thread queue: 39
get com.apple.root.default-qos queue: 41
get com.apple.root.default-qos queue: 42
get com.apple.root.utility-qos queue: 42
get com.apple.main-thread queue: 43
get com.apple.root.default-qos queue: 45
get com.apple.root.default-qos queue: 46
get com.apple.root.utility-qos queue: 46
get com.apple.main-thread queue: 47
get com.apple.root.default-qos queue: 49
test1.work at com.apple.root.default-qos queue completed
get com.apple.root.default-qos queue: 50
test2.work at com.apple.root.default-qos queue completed
get com.apple.root.utility-qos queue: 50
get com.apple.main-thread queue: 50
test1.work at com.apple.root.utility-qos queue completed
get com.apple.main-thread queue: 51
test2.work at com.apple.main-thread queue completed
get com.apple.main-thread queue: 52
get com.apple.main-thread queue: 53
get com.apple.main-thread queue: 54
get com.apple.main-thread queue: 55
get com.apple.main-thread queue: 56
get com.apple.main-thread queue: 57
get com.apple.main-thread queue: 58
get com.apple.main-thread queue: 59
get com.apple.main-thread queue: 60
test3.work at com.apple.main-thread queue completed
End. Count: 60
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