convert objc_sync_enter lock to GCD

Mixpanel/AutomaticEvents.swift

@@ -49,6 +49,7 @@ class AutomaticEvents: NSObject, SKPaymentTransactionObserver, SKProductsRequest
     var hasAddedObserver = false
     var automaticPushTracking = true
     var firstAppOpen = false
+    let awaitingTransactionsWriteLock = DispatchQueue(label: "com.mixpanel.awaiting_transactions_writeLock")
 
     func initializeEvents() {
         let firstOpenKey = "MPFirstOpen"
@@ -119,21 +120,23 @@ class AutomaticEvents: NSObject, SKPaymentTransactionObserver, SKProductsRequest
     func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
         var productsRequest = SKProductsRequest()
         var productIdentifiers: Set<String> = []
-        objc_sync_enter(awaitingTransactions)
-        for transaction:AnyObject in transactions {
-            if let trans = transaction as? SKPaymentTransaction {
-                switch trans.transactionState {
-                case .purchased:
-                    productIdentifiers.insert(trans.payment.productIdentifier)
-                    awaitingTransactions[trans.payment.productIdentifier] = trans
-                    break
-                case .failed: break
-                case .restored: break
-                default: break
+        awaitingTransactionsWriteLock.sync {
+            for transaction:AnyObject in transactions {
+                if let trans = transaction as? SKPaymentTransaction {
+                    switch trans.transactionState {
+                    case .purchased:
+                        productIdentifiers.insert(trans.payment.productIdentifier)
+                        awaitingTransactions[trans.payment.productIdentifier] = trans
+                        break
+                    case .failed: break
+                    case .restored: break
+                    default: break
+                    }
                 }
             }
         }
-        objc_sync_exit(awaitingTransactions)
+
+
         if productIdentifiers.count > 0 {
             productsRequest = SKProductsRequest(productIdentifiers: productIdentifiers)
             productsRequest.delegate = self
@@ -163,16 +166,16 @@ class AutomaticEvents: NSObject, SKPaymentTransactionObserver, SKProductsRequest
 
 
     func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
-        objc_sync_enter(awaitingTransactions)
-        for product in response.products {
-            if let trans = awaitingTransactions[product.productIdentifier] {
-                delegate?.track(event: "$ae_iap", properties: ["$ae_iap_price": "\(product.price)",
-                    "$ae_iap_quantity": trans.payment.quantity,
-                    "$ae_iap_name": product.productIdentifier])
-                awaitingTransactions.removeValue(forKey: product.productIdentifier)
+        awaitingTransactionsWriteLock.sync {
+            for product in response.products {
+                if let trans = awaitingTransactions[product.productIdentifier] {
+                    delegate?.track(event: "$ae_iap", properties: ["$ae_iap_price": "\(product.price)",
+                        "$ae_iap_quantity": trans.payment.quantity,
+                        "$ae_iap_name": product.productIdentifier])
+                    awaitingTransactions.removeValue(forKey: product.productIdentifier)
+                }
             }
         }
-        objc_sync_exit(awaitingTransactions)
     }
 
     #if DECIDE

Mixpanel/AutomaticProperties.swift

@@ -21,7 +21,6 @@ class AutomaticProperties {
     static let automaticPropertiesLock = ReadWriteLock(label: "automaticPropertiesLock")
 
     static var properties: InternalProperties = {
-        objc_sync_enter(AutomaticProperties.self); defer { objc_sync_exit(AutomaticProperties.self) }
         var p = InternalProperties()
         #if os(iOS) || TV_OS
         let screenSize = UIScreen.main.bounds.size
@@ -62,7 +61,6 @@ class AutomaticProperties {
     }()
 
     static var peopleProperties: InternalProperties = {
-        objc_sync_enter(AutomaticProperties.self); defer { objc_sync_exit(AutomaticProperties.self) }
         var p = InternalProperties()
         let infoDict = Bundle.main.infoDictionary
         if let infoDict = infoDict {

Mixpanel/Flush.swift

@@ -17,33 +17,33 @@ protocol FlushDelegate {
 }
 
 class Flush: AppLifecycle {
-    let lock: ReadWriteLock
     var timer: Timer?
     var delegate: FlushDelegate?
     var useIPAddressForGeoLocation = true
     var flushRequest: FlushRequest
     var flushOnBackground = true
     var _flushInterval = 0.0
+    private let flushIntervalReadWriteLock: DispatchQueue
+
     var flushInterval: Double {
         set {
-            objc_sync_enter(self)
-            _flushInterval = newValue
-            objc_sync_exit(self)
+            flushIntervalReadWriteLock.sync(flags: .barrier, execute: {
+                _flushInterval = newValue
+            })
 
             delegate?.flush(completion: nil)
             startFlushTimer()
         }
         get {
-            objc_sync_enter(self)
-            defer { objc_sync_exit(self) }
-
-            return _flushInterval
+            flushIntervalReadWriteLock.sync {
+                return _flushInterval
+            }
         }
     }
 
-    required init(basePathIdentifier: String, lock: ReadWriteLock) {
+    required init(basePathIdentifier: String) {
         self.flushRequest = FlushRequest(basePathIdentifier: basePathIdentifier)
-        self.lock = lock
+        flushIntervalReadWriteLock = DispatchQueue(label: "com.mixpanel.flush_interval.lock", attributes: .concurrent)
     }
 
     func flushEventsQueue(_ eventsQueue: Queue, automaticEventsEnabled: Bool?) -> Queue? {

Mixpanel/MixpanelInstance.swift

@@ -282,7 +282,7 @@ open class MixpanelInstance: CustomDebugStringConvertible, FlushDelegate, AEDele
         }
         self.name = name
         self.readWriteLock = ReadWriteLock(label: "globalLock")
-        flushInstance = Flush(basePathIdentifier: name, lock: self.readWriteLock)
+        flushInstance = Flush(basePathIdentifier: name)
         #if DECIDE
             decideInstance = Decide(basePathIdentifier: name, lock: self.readWriteLock)
         #endif // DECIDE
@@ -357,7 +357,7 @@ open class MixpanelInstance: CustomDebugStringConvertible, FlushDelegate, AEDele
         }
         self.name = name
         self.readWriteLock = ReadWriteLock(label: "globalLock")
-        flushInstance = Flush(basePathIdentifier: name, lock: self.readWriteLock)
+        flushInstance = Flush(basePathIdentifier: name)
         let label = "com.mixpanel.\(self.apiToken)"
         trackingQueue = DispatchQueue(label: label)
         sessionMetadata = SessionMetadata(trackingQueue: trackingQueue)

Mixpanel/Swizzle.swift

@@ -8,19 +8,6 @@
 
 import Foundation
 
-extension DispatchQueue {
-    private static var _onceTracker = [String]()
-
-    class func once(token: String, block: () -> Void) {
-        objc_sync_enter(self); defer { objc_sync_exit(self) }
-        if _onceTracker.contains(token) {
-            return
-        }
-        _onceTracker.append(token)
-        block()
-    }
-}
-
 class Swizzler {
     static var swizzles = [Method: Swizzle]()
 

Mixpanel/WebSocketWrapper.swift

@@ -41,11 +41,13 @@ class WebSocketWrapper: WebSocketDelegate {
     var connectivityIndiciatorWindow: UIWindow? = nil
     let connectCallback: (() -> Void)?
     let disconnectCallback: (() -> Void)?
+    let sessionObjectLock: DispatchQueue
 
     init(url: URL, keepTrying: Bool, connectCallback: (() -> Void)?, disconnectCallback: (() -> Void)?) {
         open = false
         connected = false
         session = [String: Any]()
+        sessionObjectLock = DispatchQueue(label: "com.mixpanel.session_object_lock", attributes: .concurrent)
         self.url = url
         self.connectCallback = connectCallback
         self.disconnectCallback = disconnectCallback
@@ -65,17 +67,15 @@ class WebSocketWrapper: WebSocketDelegate {
     }
 
     func setSessionObjectSynchronized(with value: Any, for key: String) {
-        objc_sync_enter(self)
-        defer { objc_sync_exit(self) }
-
-        session[key] = value
+        sessionObjectLock.sync(flags: .barrier, execute: {
+            session[key] = value
+        })
     }
 
     func getSessionObjectSynchronized(for key: String) -> Any? {
-        objc_sync_enter(self)
-        defer { objc_sync_exit(self) }
-
-        return session[key]
+        sessionObjectLock.sync {
+            return session[key]
+        }
     }
 
     func open(initiate: Bool, maxInterval: Int = 0, maxRetries: Int = 0) {

MixpanelDemo/MixpanelDemoTests/MixpanelBaseTests.swift

@@ -57,14 +57,12 @@ class MixpanelBaseTests: XCTestCase, MixpanelDelegate {
 
     func deleteOptOutSettings(mixpanelInstance: MixpanelInstance)
     {
-        objc_sync_enter(self)
         let filePath = Persistence.filePathWithType(.optOutStatus, token: mixpanelInstance.apiToken)
         do {
             try FileManager.default.removeItem(atPath: filePath!)
         } catch {
             Logger.info(message: "Unable to remove file at path: \(filePath!)")
         }
-        objc_sync_exit(self)
     }
 
     func mixpanelWillFlush(_ mixpanel: MixpanelInstance) -> Bool {