Add TODOs with notes for optimization and commented out logging code.

To evaluate the logs this produces:

grep -Eo or-match.* ~/Freenet/logs/freenet-latest.log | \
  sort | uniq -c | sort -h \
  > misordered-MessageFilter-or-matches.log
cat misordered-MessageFilter-or-matches.log

this produces a list of MessageFilters with the frequency for pairs
where the first is the one that did not match and the second is the
filter that did match.

Author: ArneBab

src/freenet/io/comm/MessageFilter.java

@@ -65,6 +65,9 @@ private MessageFilter() {
     }
 
     public static MessageFilter create() {
+			  // TODO: move to a builder so we can get rid of the synchronized(_fields) in match,
+			  //  the most expensive method in all of fred.
+			  // TODO: move source and type into create to get rid of the null-checks in match.
         return new MessageFilter();
     }
 
@@ -178,6 +181,8 @@ public MessageFilter setField(String fieldName, Object fieldValue) {
 	 * Modifies the filter so that it returns true if either it or the filter in the argument returns true.
 	 * Multiple combinations must be nested: such as filter1.or(filter2.or(filter3))).
 	 * filter2 will be checked before filter1, so make sure to add the most common last.
+	 * TODO: change the ordering in match: A.or(B) should first check A, like in A || B.
+	 * TODO: ensure for all usages of or(...) that the most likely package is checked first.
 	 * @return reference to this, the modified filter.
 	 */
 	public MessageFilter or(MessageFilter or) {
@@ -213,8 +218,9 @@ public MATCHED match(Message m, long now) {
 	public MATCHED match(Message m, boolean noTimeout, long now) {
 		if(_or != null) {
 			MATCHED matched = _or.match(m, noTimeout, now);
-			if(matched != MATCHED.NONE)
+			if(matched != MATCHED.NONE) {
 				return matched; // Filter is matched once only. That includes timeouts.
+			}
 		}
 
 		final MATCHED resultNoMatch = _timeout < now ? MATCHED.TIMED_OUT : MATCHED.NONE;
@@ -242,6 +248,10 @@ public MATCHED match(Message m, boolean noTimeout, long now) {
 			if(logMINOR) Logger.minor(this, "Matched but timed out: "+this);
 			return MATCHED.TIMED_OUT_AND_MATCHED;
 		}
+		// debugging output to optimize ordering of or-combined MessageFilters
+		// if (_or != null) {
+		// 	Logger.error(this, "Filter or-match failed: or: " + _or._type.getName() + " this: " + this._type.getName());
+		// }
 		return MATCHED.MATCHED;
 	}
 

src/freenet/node/PeerMessageQueue.java

@@ -20,6 +20,8 @@
  * @author Matthew Toseland <[email protected]> (0xE43DA450)
  */
 public class PeerMessageQueue {
+	// TODO: check whether we can use a standard PriorityBlockingQueue (since Java 8)
+	//  instead of our own DoublyLinkedList implementation.
 
 	private static volatile boolean logMINOR;
 	private static volatile boolean logDEBUG;