From 58cc6aec86590efca01e03b46225e8609ead623c Mon Sep 17 00:00:00 2001
From: Trustin Lee <trustin@gmail.com>
Date: Fri, 12 Aug 2011 14:03:48 +0900
Subject: [PATCH] NETTY-431 HashedWheelTimer's TimerTask may execute after call
 to Timeout.cancel()

* Replaced a volatile boolean flag and system date access with an atomic integer flag.
---
 .../jboss/netty/util/HashedWheelTimer.java    | 20 ++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/main/java/org/jboss/netty/util/HashedWheelTimer.java b/src/main/java/org/jboss/netty/util/HashedWheelTimer.java
index a41c9a5820..63264b2ce3 100644
--- a/src/main/java/org/jboss/netty/util/HashedWheelTimer.java
+++ b/src/main/java/org/jboss/netty/util/HashedWheelTimer.java
@@ -472,11 +472,15 @@ public class HashedWheelTimer implements Timer {
 
     private final class HashedWheelTimeout implements Timeout {
 
+        private static final int ST_INIT = 0;
+        private static final int ST_CANCELLED = 1;
+        private static final int ST_EXPIRED = 2;
+
         private final TimerTask task;
         final long deadline;
         volatile int stopIndex;
         volatile long remainingRounds;
-        private volatile boolean cancelled;
+        private final AtomicInteger state = new AtomicInteger(ST_INIT);
 
         HashedWheelTimeout(TimerTask task, long deadline) {
             this.task = task;
@@ -492,26 +496,24 @@ public class HashedWheelTimer implements Timer {
         }
 
         public void cancel() {
-            if (isExpired()) {
+            if (!state.compareAndSet(ST_INIT, ST_CANCELLED)) {
+                // TODO return false
                 return;
             }
-
-            cancelled = true;
-
-            // Might be called more than once, but doesn't matter.
+            
             wheel[stopIndex].remove(this);
         }
 
         public boolean isCancelled() {
-            return cancelled;
+            return state.get() == ST_CANCELLED;
         }
 
         public boolean isExpired() {
-            return cancelled || System.currentTimeMillis() > deadline;
+            return state.get() != ST_INIT;
         }
 
         public void expire() {
-            if (cancelled) {
+            if (!state.compareAndSet(ST_INIT, ST_EXPIRED)) {
                 return;
             }