From 3252a2a77cefb4e64e32fc3203cf6987da17e849 Mon Sep 17 00:00:00 2001
From: Gaston Dombiak <gaston@jivesoftware.com>
Date: Mon, 12 Jun 2006 16:32:18 +0000
Subject: [PATCH] keep alive final fixes. SMACK-141

git-svn-id: http://svn.igniterealtime.org/svn/repos/smack/trunk@3972 b35dd754-fafc-0310-a699-88a17e54d16e
---
 .../org/jivesoftware/smack/PacketWriter.java  | 72 +++++++++++++------
 .../jivesoftware/smack/XMPPConnection.java    |  3 +
 2 files changed, 54 insertions(+), 21 deletions(-)

diff --git a/source/org/jivesoftware/smack/PacketWriter.java b/source/org/jivesoftware/smack/PacketWriter.java
index 76228753a..93cb37e68 100644
--- a/source/org/jivesoftware/smack/PacketWriter.java
+++ b/source/org/jivesoftware/smack/PacketWriter.java
@@ -41,18 +41,24 @@ class PacketWriter {
     private Thread writerThread;
     private Writer writer;
     private XMPPConnection connection;
-    private LinkedList queue;
+    final private LinkedList queue;
     private boolean done = false;
     
-    private List listeners = new ArrayList();
+    final private List listeners = new ArrayList();
     private boolean listenersDeleted = false;
 
+    /**
+     * Timestamp when the last stanza was sent to the server. This information is used
+     * by the keep alive process to only send heartbeats when the connection has been idle.
+     */
+    private long lastActive = System.currentTimeMillis();
+
     /**
      * List of PacketInterceptor that will be notified when a new packet is about to be
      * sent to the server. These interceptors may modify the packet before it is being
      * actually sent to the server.
      */
-    private List interceptors = new ArrayList();
+    final private List interceptors = new ArrayList();
     /**
      * Flag that indicates if an interceptor was deleted. This is an optimization flag.
      */
@@ -75,15 +81,6 @@ class PacketWriter {
         };
         writerThread.setName("Smack Packet Writer");
         writerThread.setDaemon(true);
-
-        // Schedule a keep-alive task to run if the feature is enabled. will write
-        // out a space character each time it runs to keep the TCP/IP connection open.
-        int keepAliveInterval = SmackConfiguration.getKeepAliveInterval();
-        if (keepAliveInterval > 0) {
-            Thread keepAliveThread = new Thread(new KeepAliveTask(keepAliveInterval));
-            keepAliveThread.setDaemon(true);
-            keepAliveThread.start();
-        }
     }
 
     /**
@@ -198,6 +195,22 @@ class PacketWriter {
         writerThread.start();
     }
 
+    /**
+     * Starts the keep alive process. A white space (aka heartbeat) is going to be
+     * sent to the server every 30 seconds (by default) since the last stanza was sent
+     * to the server.
+     */
+    void startKeepAliveProcess() {
+        // Schedule a keep-alive task to run if the feature is enabled. will write
+        // out a space character each time it runs to keep the TCP/IP connection open.
+        int keepAliveInterval = SmackConfiguration.getKeepAliveInterval();
+        if (keepAliveInterval > 0) {
+            Thread keepAliveThread = new Thread(new KeepAliveTask(keepAliveInterval));
+            keepAliveThread.setDaemon(true);
+            keepAliveThread.start();
+        }
+    }
+
     void setWriter(Writer writer) {
         this.writer = writer;
     }
@@ -221,7 +234,9 @@ class PacketWriter {
                 try {
                     queue.wait(2000);
                 }
-                catch (InterruptedException ie) { }
+                catch (InterruptedException ie) {
+                    // Do nothing
+                }
             }
             if (queue.size() > 0) {
                 return (Packet)queue.removeLast();
@@ -243,6 +258,8 @@ class PacketWriter {
                     synchronized (writer) {
                         writer.write(packet.toXML());
                         writer.flush();
+                        // Keep track of the last time a stanza was sent to the server
+                        lastActive = System.currentTimeMillis();
                     }
                 }
             }
@@ -251,12 +268,16 @@ class PacketWriter {
                 writer.write("</stream:stream>");
                 writer.flush();
             }
-            catch (Exception e) { }
+            catch (Exception e) {
+                // Do nothing
+            }
             finally {
                 try {
                     writer.close();
                 }
-                catch (Exception e) { }
+                catch (Exception e) {
+                    // Do nothing
+                }
             }
         }
         catch (IOException ioe){
@@ -440,20 +461,29 @@ class PacketWriter {
                 // properly finish TLS negotiation and then start sending heartbeats.
                 Thread.sleep(15000);
             }
-            catch (InterruptedException ie) { }
+            catch (InterruptedException ie) {
+                // Do nothing
+            }
             while (!done) {
                 synchronized (writer) {
-                    try {
-                        writer.write(" ");
-                        writer.flush();
+                    // Send heartbeat if no packet has been sent to the server for a given time
+                    if (System.currentTimeMillis() - lastActive >= delay) {
+                        try {
+                            writer.write(" ");
+                            writer.flush();
+                        }
+                        catch (Exception e) {
+                            // Do nothing
+                        }
                     }
-                    catch (Exception e) { }
                 }
                 try {
                     // Sleep until we should write the next keep-alive.
                     Thread.sleep(delay);
                 }
-                catch (InterruptedException ie) { }
+                catch (InterruptedException ie) {
+                    // Do nothing
+                }
             }
         }
     }
diff --git a/source/org/jivesoftware/smack/XMPPConnection.java b/source/org/jivesoftware/smack/XMPPConnection.java
index 3999097e3..af90568e8 100644
--- a/source/org/jivesoftware/smack/XMPPConnection.java
+++ b/source/org/jivesoftware/smack/XMPPConnection.java
@@ -876,6 +876,9 @@ public class XMPPConnection {
             // Make note of the fact that we're now connected.
             connected = true;
 
+            // Start keep alive process (after TLS was negotiated - if available)
+            packetWriter.startKeepAliveProcess();
+
             // Notify that a new connection has been established
             connectionEstablished(this);