Fixed stack overflow error

src/main/java/org/jboss/netty/channel/socket/nio/NioSocketChannel.java

@@ -59,8 +59,20 @@ abstract class NioSocketChannel extends AbstractChannel
     final Runnable writeTask = new WriteTask();
     final AtomicInteger writeBufferSize = new AtomicInteger();
     final Queue<MessageEvent> writeBuffer = new WriteBuffer();
-    boolean wasWritable;
+
-    boolean mightNeedToNotifyUnwritability;
+    /** Previous return value of isWritable() */
+    boolean oldWritable;
+    /**
+     * Set to true if the amount of data in the writeBuffer exceeds
+     * the high water mark, as specified in NioSocketChannelConfig.
+     */
+    boolean exceededHighWaterMark;
+    /**
+     * true if and only if NioWorker is firing an event which might cause
+     * infinite recursion.
+     */
+    boolean firingEvent;
+
     MessageEvent currentWriteEvent;
     int currentWriteIndex;
 
@@ -160,7 +172,7 @@ abstract class NioSocketChannel extends AbstractChannel
                 int newWriteBufferSize = writeBufferSize.addAndGet(
                         -((ChannelBuffer) e.getMessage()).readableBytes());
                 if (newWriteBufferSize <= getConfig().getWriteBufferLowWaterMark()) {
-                    mightNeedToNotifyUnwritability = true;
+                    exceededHighWaterMark = true;
                 }
             }
             return e;

src/main/java/org/jboss/netty/channel/socket/nio/NioWorker.java

@@ -479,25 +479,35 @@ class NioWorker implements Runnable {
 
     private static void fireChannelInterestChangedIfNecessary(
             NioSocketChannel channel, boolean open) {
-        int interestOps = channel.getRawInterestOps();
+        if (channel.firingEvent) {
-        boolean wasWritable = channel.wasWritable;
+            // Prevent StackOverflowError.
-        boolean writable = channel.wasWritable = open? channel.isWritable() : false;
+            return;
-        if (wasWritable) {
+        }
-            if (writable) {
+
-                if (channel.mightNeedToNotifyUnwritability) {
+        channel.firingEvent = true;
-                    channel.mightNeedToNotifyUnwritability = false;
+        try {
+            int interestOps = channel.getRawInterestOps();
+            boolean wasWritable = channel.oldWritable;
+            boolean writable = channel.oldWritable = open? channel.isWritable() : false;
+            if (wasWritable) {
+                if (writable) {
+                    if (channel.exceededHighWaterMark) {
+                        channel.exceededHighWaterMark = false;
+                        fireChannelInterestChanged(channel, interestOps | Channel.OP_WRITE);
+                        fireChannelInterestChanged(channel, interestOps & ~Channel.OP_WRITE);
+                    }
+                } else {
                     fireChannelInterestChanged(channel, interestOps | Channel.OP_WRITE);
-                    fireChannelInterestChanged(channel, interestOps & ~Channel.OP_WRITE);
                 }
             } else {
-                fireChannelInterestChanged(channel, interestOps | Channel.OP_WRITE);
+                if (writable) {
-            }
+                    fireChannelInterestChanged(channel, interestOps & ~Channel.OP_WRITE);
-        } else {
+                } else {
-            if (writable) {
+                    fireChannelInterestChanged(channel, interestOps | Channel.OP_WRITE);
-                fireChannelInterestChanged(channel, interestOps & ~Channel.OP_WRITE);
+                }
-            } else {
-                fireChannelInterestChanged(channel, interestOps | Channel.OP_WRITE);
             }
+        } finally {
+            channel.firingEvent = false;
         }
     }