This code freezes UNITY!

Unity Engine
1

When i press play button on unity, this works like diamonds. But when i press play second time unity freezes, could threads cause this?

import System;
import System.IO;
import System.Net;
import System.Net.Sockets;
import System.Text;
import System.Threading;


var server  : TcpListener; 
var client  : TcpClient;
var stream  : NetworkStream;
var reader  : StreamReader;
var writer  : StreamWriter;
var msg     : String;
var thread = Thread(Parse);
var UniqueHash : String;
var Running : boolean;

function Start(){
DontDestroyOnLoad(this);
}

function Update(){
if(Var.State == 1){
        client = new TcpClient("127.0.0.1", 6112);
        stream = client.GetStream();    
        reader = new StreamReader(stream);
        writer = new StreamWriter(stream);
        Running = true;
        thread.IsBackground = true;
        thread.Start();
        Var.State = 2;
    }
    
}

function OnApplicationQuit()
{
Running = false;
thread.Join(500);
Debug.Log("Thread Terminated");
}

function Send(data : String){
stream = client.GetStream();
writer.WriteLine(data);
writer.Flush();

}


function Parse()
{ 
try{
while(Running){
	stream = client.GetStream();
if(stream.DataAvailable){
    msg = reader.ReadLine();
    
	        if (msg == null){}
	        else
	        {
	            HandleMessage(msg);
	            msg = "";
	        }
    }
    else {
    Thread.Sleep(100);
    }
 }
}
catch (ThreadAbortException)
    {
        print("exception");
    }
}




function HandleMessage(data : String){

var Header : String;

Header = data.Substring(0,4);

        switch (Header){

            case "0x00" : onPacket0x00(data);
            break;

            case "0x01" : onPacket0x01(data);
            break;

        default:
        print ("Unparsed packet: " + Header + " Data: " + data);
        break;

    }
    data = "";
    Header = "";

}

 

function onPacket0x00(data : String) {
Var.State = 3;
UniqueHash = data.Substring(4,data.Length - 4);
Debug.Log("Connected! Hash: " + UniqueHash); 
Send("0x01" + UniqueHash + "/" + Var.Username + "/" + Var.Password);
}

 

function onPacket0x01(data : String) {
Debug.Log("Login code: " + data.Substring(4,1));
}
2

Yea, sounds like you aren’t properly shutting down the extra thread. Even if you ask it to stop, if you’ve pushed to long a queue of “work” it’ll hang Unity until the thread finishes that work (upon a second play).

I suggest using a “work queue” and pushing only appropriate sized work loads to the extra thread each frame - then make sure you’re cleaning up that thread on application quit. The combination of these should keep things working well with extra threads.

3

Can you show me some pseudo code so i get some logic behind this? :slight_smile:

4

Sure. Personally, I use a combination of three classes. A priority queue class, a thread safe queue class, and a thread wrapper class.

The thread safe queue I use is virtually identical to Marc Gravell’s answer here:

The priority queue I use is:

Then for the thread wrapper, it pretty much looks like this:

public class WorkThread
{
    ThreadQueue<Action> _work;
    bool _stop;
    Thread _thread;
    
    public WorkThread(){
        _work = new ThreadQueue<Action>();
    }
    
    public void AddWork(Action work){
        _work.Enqueue(work);
    }
    
    public void StartThread(){
        _stop = false;
        _thread = new Thread(new ThreadStart(ExecuteThread));
        _thread.IsBackground = true;
        _thread.Priority = ThreadPriority.BelowNormal;
        _thread.Name = "Work Thread";
        _thread.Start();
    }
    public void StopThread(){
        _stop = true;
    }
    
    void ExecuteThread(){
        while (!_stop){
            if (_work.Count > 0){
                try{
                    Action action;
                    if (_work.TryDequeue(out action)){
                        action();
                    }
                } catch (Exception e){
                    Debug.LogError("Exception in work thread: " + e);
                }
            }
            continue;
        }
    }
}

Strictly speaking the PriorityQueue isn’t necessary depending on your project. However, I find it super helpful so that I can use this workflow:

Step 1:
Unity Thread - find any work I should be doing that isn’t currently queued, add it to the priority queue with an appropriate priority (priority queue baby)
Unity Thread - queue up a reasonable amount of work to the work thread (this is not a priority queue, only a straight FIFO queue - the ThreadQueue)

Work Thread - Chew through my queue of Actions as fast as possible.

(note: above code not tested, just a quick type up - but may just work)

5

Still having problems with this… How i do that in Javascript?

6

I got it working. I modified first post code :slight_smile: