Merge pull request #629 from Sistemium/development

SocketAckManager thread-safe acks removal

Author: nuclearace

Source/SocketAckManager.swift

@@ -51,22 +51,29 @@ private func ==(lhs: SocketAck, rhs: SocketAck) -> Bool {
 
 struct SocketAckManager {
     private var acks = Set<SocketAck>(minimumCapacity: 1)
+    private let ackSemaphore = DispatchSemaphore(value: 1)
 
     mutating func addAck(_ ack: Int, callback: @escaping AckCallback) {
         acks.insert(SocketAck(ack: ack, callback: callback))
     }
 
     /// Should be called on handle queue
     mutating func executeAck(_ ack: Int, with items: [Any], onQueue: DispatchQueue) {
+        ackSemaphore.wait()
+        defer { ackSemaphore.signal() }
         let ack = acks.remove(SocketAck(ack: ack))
 
         onQueue.async() { ack?.callback(items) }
     }
 
     /// Should be called on handle queue
     mutating func timeoutAck(_ ack: Int, onQueue: DispatchQueue) {
+        ackSemaphore.wait()
+        defer { ackSemaphore.signal() }
         let ack = acks.remove(SocketAck(ack: ack))
 
-        onQueue.async() { ack?.callback?(["NO ACK"]) }
+        onQueue.async() {
+            ack?.callback?(["NO ACK"])
+        }
     }
 }