From c25b0fdeba6aacb584b1ead4c842b47aca448db4 Mon Sep 17 00:00:00 2001
From: Branden Archer <b.m.archer4@gmail.com>
Date: Mon, 28 Dec 2015 16:12:49 -0500
Subject: [PATCH] Allow child device to establish new connection after parent
 disconnects

Previously the monitor activity would only support one connection,
after which the activity would need to be restarted. With this change,
if a connection is established with a parent device but is eventually
disconnected the child device will begin advertising again.

Note that because the child device can only support one connection
at a time currently, after the connection is established it will
now stop advertising. When a connection is lost and advertising
starts again, it may end up advertising as another service. E.g.
  ProtectBabyMonitor (2)
instead of
  ProtectBabyMonitor
---
 src/protect/babymonitor/MonitorActivity.java | 95 +++++++++++---------
 1 file changed, 53 insertions(+), 42 deletions(-)

diff --git a/src/protect/babymonitor/MonitorActivity.java b/src/protect/babymonitor/MonitorActivity.java
index b3cdd86..8b2ac99 100644
--- a/src/protect/babymonitor/MonitorActivity.java
+++ b/src/protect/babymonitor/MonitorActivity.java
@@ -42,7 +42,6 @@ public class MonitorActivity extends Activity
 
     NsdManager.RegistrationListener _registrationListener;
 
-    ServerSocket _serverSocket;
     Thread _serviceThread;
 
     private void serviceConnection(Socket socket) throws IOException
@@ -86,7 +85,6 @@ public class MonitorActivity extends Activity
         finally
         {
             audioRecord.stop();
-            socket.close();
         }
     }
 
@@ -100,57 +98,70 @@ public class MonitorActivity extends Activity
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_monitor);
 
-        try
+        _serviceThread = new Thread(new Runnable()
         {
-            // Initialize a server socket on the next available port.
-            _serverSocket = new ServerSocket(0);
-
-            // Store the chosen port.
-            int localPort = _serverSocket.getLocalPort();
-
-            registerService(localPort);
-
-            _serviceThread = new Thread(new Runnable()
+            @Override
+            public void run()
             {
-                @Override
-                public void run()
+                while(Thread.currentThread().isInterrupted() == false)
                 {
-                    try
-                    {
-                        Socket socket = _serverSocket.accept();
-                        serviceConnection(socket);
-                    }
-                    catch (IOException e)
-                    {
-                        Log.e(TAG, "Failed when serving connection", e);
-                    }
+                    ServerSocket serverSocket = null;
 
                     try
                     {
-                        _serverSocket.close();
-                    }
-                    catch (IOException e)
-                    {
+                        // Initialize a server socket on the next available port.
+                        serverSocket = new ServerSocket(0);
 
-                    }
+                        // Store the chosen port.
+                        int localPort = serverSocket.getLocalPort();
 
-                    MonitorActivity.this.runOnUiThread(new Runnable()
-                    {
-                        @Override
-                        public void run()
+                        // Register the service so that parent devices can
+                        // locate the child device
+                        registerService(localPort);
+
+                        // Wait for a parent to find us and connect
+                        Socket socket = serverSocket.accept();
+                        Log.i(TAG, "Connection from parent device received");
+
+                        // We now have a client connection.
+                        // Unregister so no other clients will
+                        // attempt to connect
+                        serverSocket.close();
+                        serverSocket = null;
+                        unregisterService();
+
+                        try
                         {
-                            final TextView statusText = (TextView) findViewById(R.id.textStatus);
-                            statusText.setText(R.string.stopped);
+                            serviceConnection(socket);
                         }
-                    });
+                        finally
+                        {
+                            socket.close();
+                        }
+                    }
+                    catch(IOException e)
+                    {
+                        Log.e(TAG, "Connection failed", e);
+                    }
+
+                    // If an exception was thrown before the connection
+                    // could be closed, clean it up
+                    if(serverSocket != null)
+                    {
+                        try
+                        {
+                            serverSocket.close();
+                        }
+                        catch (IOException e)
+                        {
+                            Log.e(TAG, "Failed to close stray connection", e);
+                        }
+                        serverSocket = null;
+                    }
                 }
-            });
-            _serviceThread.start();
-        }
-        catch (IOException e)
-        {
-            Log.e(TAG, "Failed to create server socket", e);
-        }
+            }
+        });
+        _serviceThread.start();
     }
 
     @Override