* i2psnark: Fix DHT nodes not being saved at shutdown

Log infohashes in hex
             Don't write out nodes if we don't have any

apps/i2psnark/java/src/org/klomp/snark/SnarkManager.java

@@ -37,6 +37,8 @@ import net.i2p.util.SecureFileOutputStream;
 import net.i2p.util.SimpleScheduler;
 import net.i2p.util.SimpleTimer;
 
+import org.klomp.snark.dht.DHT;
+
 /**
  * Manage multiple snarks
  */
@@ -1752,6 +1754,9 @@ public class SnarkManager implements Snark.CompleteListener {
         }
         if (_util.connected()) {
             if (count > 0) {
+                DHT dht = _util.getDHT();
+                if (dht != null)
+                    dht.stop();
                 // Schedule this even for final shutdown, as there's a chance
                 // that it's just this webapp that is stopping.
                 _context.simpleScheduler().addEvent(new Disconnector(), 60*1000);

apps/i2psnark/java/src/org/klomp/snark/dht/InfoHash.java

@@ -4,6 +4,7 @@ package org.klomp.snark.dht;
  */
 
 import net.i2p.crypto.SHA1Hash;
+import org.klomp.snark.I2PSnarkUtil;
 
 /**
  *  A 20-byte SHA1 info hash
@@ -16,4 +17,13 @@ class InfoHash extends SHA1Hash {
     public InfoHash(byte[] data) {
         super(data);
     }
+
+    @Override
+    public String toString() {
+        if (_data == null) {
+            return super.toString();
+        } else {
+            return "[InfoHash: " + I2PSnarkUtil.toHex(_data) + ']';
+        }
+    }
 }

apps/i2psnark/java/src/org/klomp/snark/dht/KRPC.java

@@ -176,8 +176,6 @@ public class KRPC implements I2PSessionMuxedListener, DHT {
         _dhtFile = new File(ctx.getConfigDir(), DHT_FILE);
         _knownNodes = new DHTNodes(ctx, _myNID);
 
-        session.addMuxedSessionListener(this, I2PSession.PROTO_DATAGRAM_RAW, _rPort);
-        session.addMuxedSessionListener(this, I2PSession.PROTO_DATAGRAM, _qPort);
         start();
     }
 
@@ -517,7 +515,11 @@ public class KRPC implements I2PSessionMuxedListener, DHT {
      *  Loads the DHT from file.
      *  Can't be restarted after stopping?
      */
-    public void start() {
+    public synchronized void start() {
+        if (_isRunning)
+            return;
+        session.addMuxedSessionListener(this, I2PSession.PROTO_DATAGRAM_RAW, _rPort);
+        session.addMuxedSessionListener(this, I2PSession.PROTO_DATAGRAM, _qPort);
         _knownNodes.start();
         _tracker.start();
         PersistDHT.loadDHT(this, _dhtFile);
@@ -536,7 +538,9 @@ public class KRPC implements I2PSessionMuxedListener, DHT {
     /**
      *  Stop everything.
      */
-    public void stop() {
+    public synchronized void stop() {
+        if (!_isRunning)
+            return;
         _isRunning = false;
         // FIXME stop the explore thread
         // unregister port listeners

apps/i2psnark/java/src/org/klomp/snark/dht/PersistDHT.java

@@ -56,6 +56,8 @@ abstract class PersistDHT {
     }
 
     public static synchronized void saveDHT(DHTNodes nodes, File file) {
+        if (nodes.isEmpty())
+            return;
         Log log = I2PAppContext.getGlobalContext().logManager().getLog(PersistDHT.class);
         int count = 0;
         long maxAge = I2PAppContext.getGlobalContext().clock().now() - MAX_AGE;