* I2CP: Cache b32 lookups client-side

* I2PTunnelHTTPClient: Use existing session for b32 lookups
                         rather than a new SimpleSession
  * Naming: Increase b32 lookup timeout to 15 sec.

core/java/src/net/i2p/client/I2PSessionImpl.java

@@ -18,6 +18,7 @@ import java.net.UnknownHostException;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.Iterator;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
@@ -140,6 +141,11 @@ abstract class I2PSessionImpl implements I2PSession, I2CPMessageReader.I2CPMessa
     private long _lastActivity;
     private boolean _isReduced;
 
+    /**
+     *  @since 0.8.9
+     */
+    private static final LookupCache _lookupCache = new LookupCache(16);
+
     /** SSL interface (only) @since 0.8.3 */
     protected static final String PROP_ENABLE_SSL = "i2cp.SSL";
 
@@ -809,6 +815,9 @@ abstract class I2PSessionImpl implements I2PSession, I2CPMessageReader.I2CPMessa
     /** called by the message handler */
     void destReceived(Destination d) {
         Hash h = d.calculateHash();
+        synchronized (_lookupCache) {
+            _lookupCache.put(h, d);
+        }
         for (LookupWaiter w : _pendingLookups) {
             if (w.hash.equals(h)) {
                 w.destination = d;
@@ -872,6 +881,11 @@ abstract class I2PSessionImpl implements I2PSession, I2CPMessageReader.I2CPMessa
      *  @return null on failure
      */
     public Destination lookupDest(Hash h, long maxWait) throws I2PSessionException {
+        synchronized (_lookupCache) {
+            Destination rv = _lookupCache.get(h);
+            if (rv != null)
+                return rv;
+        }
         if (_closed)
             return null;
         LookupWaiter waiter = new LookupWaiter(h);
@@ -952,4 +966,21 @@ abstract class I2PSessionImpl implements I2PSession, I2CPMessageReader.I2CPMessa
         buf.append(getPrefix());
         return buf.toString();
     }
+
+    /**
+     *  @since 0.8.9
+     */
+    private static class LookupCache extends LinkedHashMap<Hash, Destination> {
+        private final int _max;
+
+        public LookupCache(int max) {
+            super(max, 0.75f, true);
+            _max = max;
+        }
+
+        @Override
+        protected boolean removeEldestEntry(Map.Entry<Hash, Destination> eldest) {
+            return size() > _max;
+        }
+    }
 }

core/java/src/net/i2p/client/naming/LookupDest.java

@@ -21,7 +21,8 @@ import net.i2p.data.Hash;
  * Obviously this can take a while.
  *
  * All calls are blocking and return null on failure.
- * Timeout is set to 10 seconds in I2PSimpleSession.
+ * Timeout is 15 seconds.
+ * To do: Add methods that allow specifying the timeout.
  *
  * As of 0.8.3, standard I2PSessions support lookups,
  * including multiple lookups in parallel, and overriding
@@ -32,6 +33,8 @@ import net.i2p.data.Hash;
  */
 class LookupDest {
 
+    private static final long DEFAULT_TIMEOUT = 15*1000;
+
     protected LookupDest(I2PAppContext context) {}
 
     /** @param key 52 chars (do not include the .b32.i2p suffix) */
@@ -67,7 +70,7 @@ class LookupDest {
                 opts.put(I2PClient.PROP_TCP_PORT, s);
             I2PSession session = client.createSession(null, opts);
             session.connect();
-            rv = session.lookupDest(key);
+            rv = session.lookupDest(key, DEFAULT_TIMEOUT);
             session.destroySession();
         } catch (I2PSessionException ise) {}
         return rv;