hopefully fix nuclearace/Socket.IO-Client-Swift#27

Author: nuclearace

Diff for: SwiftIO/SocketIOClient.swift

@@ -206,8 +206,8 @@ public class SocketIOClient: NSObject {
             ackNum: self.currentAck, socket: self)
         self.ackHandlers.append(ackHandler)
 
-        dispatch_async(self.emitQueue) {[weak self] in
-            self?._emit(event, args, ack: true)
+        dispatch_async(self.emitQueue) {[weak self, ack = self.currentAck] in
+            self?._emit(event, args, ack: ack)
             return
         }
 
@@ -218,7 +218,7 @@ public class SocketIOClient: NSObject {
         return self.emitWithAck(event, args)
     }
 
-    private func _emit(event:String, _ args:[AnyObject], ack:Bool = false) {
+    private func _emit(event:String, _ args:[AnyObject], ack:Int? = nil) {
         var frame:SocketEvent
         var str:String
 
@@ -229,22 +229,22 @@ public class SocketIOClient: NSObject {
         }
 
         if hasBinary {
-            if !ack {
+            if ack == nil {
                 str = SocketEvent.createMessageForEvent(event, withArgs: items,
                     hasBinary: true, withDatas: emitDatas.count, toNamespace: self.nsp)
             } else {
                 str = SocketEvent.createMessageForEvent(event, withArgs: items,
-                    hasBinary: true, withDatas: emitDatas.count, toNamespace: self.nsp, wantsAck: self.currentAck)
+                    hasBinary: true, withDatas: emitDatas.count, toNamespace: self.nsp, wantsAck: ack)
             }
 
             self.engine?.send(str, datas: emitDatas)
         } else {
-            if !ack {
+            if ack == nil {
                 str = SocketEvent.createMessageForEvent(event, withArgs: items, hasBinary: false,
                     withDatas: 0, toNamespace: self.nsp)
             } else {
                 str = SocketEvent.createMessageForEvent(event, withArgs: items, hasBinary: false,
-                    withDatas: 0, toNamespace: self.nsp, wantsAck: self.currentAck)
+                    withDatas: 0, toNamespace: self.nsp, wantsAck: ack)
             }
 
             self.engine?.send(str)