Author: toad
Date: 2008-08-29 21:22:10 +0000 (Fri, 29 Aug 2008)
New Revision: 22216
Modified:
branches/db4o/freenet/src/freenet/support/CountingBloomFilter.java
Log:
Flag to log an error when we try to decrement a 0. This will indicate that we
are removing the same key twice, or removing a key which was never added.
Modified: branches/db4o/freenet/src/freenet/support/CountingBloomFilter.java
===================================================================
--- branches/db4o/freenet/src/freenet/support/CountingBloomFilter.java
2008-08-29 14:10:52 UTC (rev 22215)
+++ branches/db4o/freenet/src/freenet/support/CountingBloomFilter.java
2008-08-29 21:22:10 UTC (rev 22216)
@@ -13,6 +13,13 @@
* @author sdiz
*/
public class CountingBloomFilter extends BloomFilter {
+
+ private boolean warnOnRemoveFromEmpty;
+
+ public void setWarnOnRemoveFromEmpty() {
+ warnOnRemoveFromEmpty = true;
+ }
+
/**
* Constructor
*
@@ -77,6 +84,9 @@
byte b = filter.get(offset / 4);
byte v = (byte) ((b >>> offset % 4 * 2) & 3);
+ if (v == 0 && warnOnRemoveFromEmpty)
+ Logger.error(this, "Unsetting bit but already unset -
probable double remove, can cause false negatives, is very bad!", new
Exception("error"));
+
if (v == 0 || v == 3)
return; // overflow / underflow
