/*
* JBoss, Home of Professional Open Source.
*
* Copyright 2012 Red Hat, Inc. and/or its affiliates, and individual
* contributors as indicated by the @author tags.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.xnio.racecondition;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import java.lang.reflect.Field;
import org.jboss.byteman.contrib.bmunit.BMScript;
import org.jboss.byteman.contrib.bmunit.BMUnitRunner;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.xnio.Bits;
import org.xnio.ChannelListener;
import org.xnio.channels.SuspendableChannel;
import org.xnio.channels.TranslatingSuspendableChannel;
import org.xnio.mock.ConnectedStreamChannelMock;
/**
* Set read ready on a channel that is handling readable. Check if the effects of setting read ready are
* not mistakenly covered by handleReadable.
*
* @author <a href="mailto:flavia.rainone@jboss.com">Flavia Rainone</a>
*/
@RunWith(BMUnitRunner.class)
@BMScript(dir="src/test/resources")
public class SetReadReadyOnHandlingReadableChannelTestCase {
@Test
public void test() throws Exception {
// creating channel and threads
ConnectedStreamChannelMock connectedChannelMock = new ConnectedStreamChannelMock();
final MyTranslatingSuspendableChannel channel = new MyTranslatingSuspendableChannel(connectedChannelMock);
final Thread setReadReadyThread = new Thread(new SetReadReady(channel));
final Thread handleReadableThread = new Thread(new InvokeHandleReadable(channel));
// set up scenario
final ChannelListener<? super SuspendableChannel> listener = new ChannelListener<SuspendableChannel>() {
@Override
public void handleEvent(SuspendableChannel c) {
channel.clearReadReady();
}
};
channel.getReadSetter().set(listener);
channel.resumeReads();
channel.setReadRequiresWrite();
channel.handleReadable();
assertFalse(channel.isReadReady());
assertFalse(connectedChannelMock.isReadResumed());
// first, try to invoke handleReadable and then setReadReady
System.out.println("Attempt 1: invoke handleReadable before setReadReady");
channel.handleReadable();
channel.setReadReady();
assertTrue(channel.isReadReady());
assertTrue(connectedChannelMock.isReadAwaken());
// clear everything
channel.clearReadReady();
channel.handleReadable();
assertFalse(channel.isReadReady());
assertFalse(connectedChannelMock.isReadResumed());
// now, try the opposite, invoke handleReadable after setReadReady()
System.out.println("Attempt 2: invoke handleReadable after setReadReady");
channel.setReadReady();
channel.handleReadable();
assertFalse(channel.isReadReady());
assertTrue(connectedChannelMock.isReadAwaken());
channel.clearReadReady();
channel.handleReadable();
assertFalse(channel.isReadReady());
assertFalse(connectedChannelMock.isReadResumed());
System.out.println("Attempt 3: race condition scenario involving handleReadable and setReadReady");
// finally, create the race condition scenario... handleReadable and setReadReady occur
// practically at the same time (see SetReadReadyOnHandlingReadableChannelTestCase.btm)
setReadReadyThread.start();
handleReadableThread.start();
// joining threads
setReadReadyThread.join();
handleReadableThread.join();
assertFalse(channel.isReadReady());
assertTrue(connectedChannelMock.isReadResumed());
}
private static class SetReadReady implements Runnable {
private MyTranslatingSuspendableChannel channel;
public SetReadReady(MyTranslatingSuspendableChannel channel) {
this.channel = channel;
}
@Override
public void run() {
channel.setReadReady();
}
}
private static class InvokeHandleReadable implements Runnable {
private MyTranslatingSuspendableChannel channel;
public InvokeHandleReadable(MyTranslatingSuspendableChannel channel) {
this.channel = channel;
}
@Override
public void run() {
channel.handleReadable();
}
}
private static class MyTranslatingSuspendableChannel extends TranslatingSuspendableChannel<SuspendableChannel, SuspendableChannel> {
private static final int READ_READY;
private static final Field stateField;
static {
try {
Field READ_READY_field = TranslatingSuspendableChannel.class.getDeclaredField("READ_READY");
READ_READY_field.setAccessible(true);
READ_READY = READ_READY_field.getInt(null);
stateField = TranslatingSuspendableChannel.class.getDeclaredField("state");
stateField.setAccessible(true);
} catch (RuntimeException e) {
throw e;
} catch (Exception e) {
throw new RuntimeException("Unexpected exception " + e);
}
}
protected MyTranslatingSuspendableChannel(SuspendableChannel c) {
super(c);
}
public void handleReadable() {
super.handleReadable();
}
public void setReadReady() {
super.setReadReady();
}
public void clearReadReady() {
super.clearReadReady();
}
public boolean isReadReady() throws Exception {
return Bits.allAreSet(stateField.getInt(this), READ_READY);
}
public void setReadRequiresWrite() {
super.setReadRequiresWrite();
}
}
}