From cca59f7e91f87e4bb45b99752cc7f5d37d5381b9 Mon Sep 17 00:00:00 2001
From: Federico Fissore <f.fissore@arduino.cc>
Date: Fri, 14 Jun 2013 16:43:05 +0200
Subject: [PATCH] NetworkDiscovery is a bit more responsive when boards go
 OFFLINE

---
 .../discoverers/NetworkDiscovery.java         | 69 ++++++++++++-------
 1 file changed, 43 insertions(+), 26 deletions(-)

diff --git a/app/src/cc/arduino/packages/discoverers/NetworkDiscovery.java b/app/src/cc/arduino/packages/discoverers/NetworkDiscovery.java
index 7b0fb93fa..630109ade 100644
--- a/app/src/cc/arduino/packages/discoverers/NetworkDiscovery.java
+++ b/app/src/cc/arduino/packages/discoverers/NetworkDiscovery.java
@@ -1,33 +1,52 @@
 package cc.arduino.packages.discoverers;
 
-import java.io.IOException;
-import java.net.InetAddress;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
-
-import javax.jmdns.JmDNS;
-import javax.jmdns.NetworkTopologyDiscovery;
-import javax.jmdns.ServiceEvent;
-import javax.jmdns.ServiceInfo;
-import javax.jmdns.ServiceListener;
-import javax.jmdns.impl.DNSTaskStarter;
-
+import cc.arduino.packages.BoardPort;
+import cc.arduino.packages.Discovery;
 import processing.app.Base;
 import processing.app.helpers.PreferencesMap;
 import processing.app.zeroconf.jmdns.ArduinoDNSTaskStarter;
-import cc.arduino.packages.BoardPort;
-import cc.arduino.packages.Discovery;
+
+import javax.jmdns.*;
+import javax.jmdns.impl.DNSTaskStarter;
+import java.io.IOException;
+import java.net.Inet4Address;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
 
 public class NetworkDiscovery implements Discovery, ServiceListener {
 
-  private JmDNS jmDNS;
-  private List<BoardPort> ports = new CopyOnWriteArrayList<BoardPort>();
+  private List<BoardPort> ports;
+
+  public NetworkDiscovery() {
+    DNSTaskStarter.Factory.setClassDelegate(new ArduinoDNSTaskStarter());
+    this.ports = new ArrayList<BoardPort>();
+  }
 
   @Override
   public List<BoardPort> discovery() {
+    List<BoardPort> ports = clonePortsList();
+    Iterator<BoardPort> iterator = ports.iterator();
+    while (iterator.hasNext()) {
+      try {
+        InetAddress address = Inet4Address.getByName(iterator.next().getAddress());
+        if (!address.isReachable(100)) {
+          iterator.remove();
+        }
+      } catch (UnknownHostException e) {
+        iterator.remove();
+      } catch (IOException e) {
+        iterator.remove();
+      }
+    }
+    return ports;
+  }
+
+  private List<BoardPort> clonePortsList() {
     synchronized (this) {
-      return new ArrayList<BoardPort>(ports);
+      return new ArrayList<BoardPort>(this.ports);
     }
   }
 
@@ -37,10 +56,8 @@ public class NetworkDiscovery implements Discovery, ServiceListener {
 
   @Override
   public void start() throws IOException {
-    DNSTaskStarter.Factory.setClassDelegate(new ArduinoDNSTaskStarter());
-    for (InetAddress addr : NetworkTopologyDiscovery.Factory.getInstance()
-        .getInetAddresses()) {
-      jmDNS = JmDNS.create(addr);
+    for (InetAddress addr : NetworkTopologyDiscovery.Factory.getInstance().getInetAddresses()) {
+      JmDNS jmDNS = JmDNS.create(addr);
       jmDNS.addServiceListener("_arduino._tcp.local.", this);
     }
   }
@@ -65,8 +82,9 @@ public class NetworkDiscovery implements Discovery, ServiceListener {
 
     dns.requestServiceInfo(type, name);
     ServiceInfo serviceInfo = dns.getServiceInfo(type, name);
-    if (serviceInfo != null)
+    if (serviceInfo != null) {
       dns.requestServiceInfo(type, name);
+    }
   }
 
   @Override
@@ -97,11 +115,10 @@ public class NetworkDiscovery implements Discovery, ServiceListener {
 
     String label = name + " at " + address;
     if (board != null) {
-      String boardName = Base.getPlatform()
-          .resolveDeviceByBoardID(Base.packages, board);
+      String boardName = Base.getPlatform().resolveDeviceByBoardID(Base.packages, board);
       label += " (" + boardName + ")";
     }
-    
+
     BoardPort port = new BoardPort();
     port.setAddress(address);
     port.setBoardName(name);