/*
* JBoss, Home of Professional Open Source
*
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* by the @author tags. See the COPYRIGHT.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.netty.channel.socket.nio;
import static org.jboss.netty.channel.Channels.*;
import java.io.IOException;
import java.nio.channels.AsynchronousCloseException;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.NotYetConnectedException;
import java.nio.channels.ScatteringByteChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.util.Iterator;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelException;
import org.jboss.netty.channel.ChannelFuture;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.logging.InternalLogger;
import org.jboss.netty.logging.InternalLoggerFactory;
import org.jboss.netty.util.LinkedTransferQueue;
import org.jboss.netty.util.ThreadRenamingRunnable;
/**
*
* @author The Netty Project (netty-dev@lists.jboss.org)
* @author Trustin Lee (tlee@redhat.com)
*
* @version $Rev: 534 $, $Date: 2008-11-28 15:45:16 +0900 (Fri, 28 Nov 2008) $
*
*/
class NioWorker implements Runnable {
private static final InternalLogger logger =
InternalLoggerFactory.getInstance(NioWorker.class);
private static final int CONSTRAINT_LEVEL = NioProviderMetadata.CONSTRAINT_LEVEL;
private static final boolean USE_DIRECT_BUFFER = false; // Hard-coded for now
private final int bossId;
private final int id;
private final Executor executor;
private boolean started;
private volatile Thread thread;
volatile Selector selector;
private final AtomicBoolean wakenUp = new AtomicBoolean();
private final ReadWriteLock selectorGuard = new ReentrantReadWriteLock();
private final Object startStopLock = new Object();
private final Queue<Runnable> registerTaskQueue = new LinkedTransferQueue<Runnable>();
private final Queue<Runnable> writeTaskQueue = new LinkedTransferQueue<Runnable>();
NioWorker(int bossId, int id, Executor executor) {
this.bossId = bossId;
this.id = id;
this.executor = executor;
}
void register(NioSocketChannel channel, ChannelFuture future) {
boolean server = !(channel instanceof NioClientSocketChannel);
Runnable registerTask = new RegisterTask(channel, future, server);
Selector selector;
synchronized (startStopLock) {
if (!started) {
// Open a selector if this worker didn't start yet.
try {
this.selector = selector = Selector.open();
} catch (Throwable t) {
throw new ChannelException(
"Failed to create a selector.", t);
}
// Start the worker thread with the new Selector.
String threadName =
(server ? "New I/O server worker #"
: "New I/O client worker #") + bossId + '-' + id;
boolean success = false;
try {
executor.execute(new ThreadRenamingRunnable(this, threadName));
success = true;
} finally {
if (!success) {
// Release the Selector if the execution fails.
try {
selector.close();
} catch (Throwable t) {
logger.warn("Failed to close a selector.", t);
}
this.selector = selector = null;
// The method will return to the caller at this point.
}
}
} else {
// Use the existing selector if this worker has been started.
selector = this.selector;
}
assert selector != null && selector.isOpen();
started = true;
registerTaskQueue.offer(registerTask);
}
if (wakenUp.compareAndSet(false, true)) {
selector.wakeup();
}
}
public void run() {
thread = Thread.currentThread();
boolean shutdown = false;
Selector selector = this.selector;
for (;;) {
wakenUp.set(false);
if (CONSTRAINT_LEVEL != 0) {
selectorGuard.writeLock().lock();
// This empty synchronization block prevents the selector
// from acquiring its lock.
selectorGuard.writeLock().unlock();
}
try {
int selectedKeyCount = selector.select(500);
processRegisterTaskQueue();
processWriteTaskQueue();
if (selectedKeyCount > 0) {
processSelectedKeys(selector.selectedKeys());
}
// Exit the loop when there's nothing to handle.
// The shutdown flag is used to delay the shutdown of this
// loop to avoid excessive Selector creation when
// connections are registered in a one-by-one manner instead of
// concurrent manner.
if (selector.keys().isEmpty()) {
if (shutdown ||
executor instanceof ExecutorService && ((ExecutorService) executor).isShutdown()) {
synchronized (startStopLock) {
if (registerTaskQueue.isEmpty() && selector.keys().isEmpty()) {
started = false;
try {
selector.close();
} catch (IOException e) {
logger.warn(
"Failed to close a selector.", e);
} finally {
this.selector = null;
}
break;
} else {
shutdown = false;
}
}
} else {
// Give one more second.
shutdown = true;
}
} else {
shutdown = false;
}
} catch (Throwable t) {
logger.warn(
"Unexpected exception in the selector loop.", t);
// Prevent possible consecutive immediate failures that lead to
// excessive CPU consumption.
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// Ignore.
}
}
}
}
private void processRegisterTaskQueue() {
for (;;) {
final Runnable task = registerTaskQueue.poll();
if (task == null) {
break;
}
task.run();
}
}
private void processWriteTaskQueue() {
for (;;) {
final Runnable task = writeTaskQueue.poll();
if (task == null) {
break;
}
task.run();
}
}
private static void processSelectedKeys(Set<SelectionKey> selectedKeys) {
for (Iterator<SelectionKey> i = selectedKeys.iterator(); i.hasNext();) {
SelectionKey k = i.next();
i.remove();
if (!k.isValid()) {
close(k);
continue;
}
if (k.isReadable()) {
// TODO Replace ReceiveBufferSizePredictor with
// ChannelBufferAllocator and let user specify it per
// Channel. (Netty 3.1)
if (USE_DIRECT_BUFFER) {
readIntoDirectBuffer(k);
} else {
readIntoHeapBuffer(k);
}
}
if (!k.isValid()) {
close(k);
continue;
}
if (k.isWritable()) {
write(k);
}
}
}
private static void readIntoHeapBuffer(SelectionKey k) {
ScatteringByteChannel ch = (ScatteringByteChannel) k.channel();
NioSocketChannel channel = (NioSocketChannel) k.attachment();
ReceiveBufferSizePredictor predictor =
channel.getConfig().getReceiveBufferSizePredictor();
ChannelBuffer buf = ChannelBuffers.buffer(predictor.nextReceiveBufferSize());
int ret = 0;
int readBytes = 0;
boolean failure = true;
try {
while ((ret = buf.writeBytes(ch, buf.writableBytes())) > 0) {
readBytes += ret;
if (!buf.writable()) {
break;
}
}
failure = false;
} catch (AsynchronousCloseException e) {
// Can happen, and does not need a user attention.
} catch (Throwable t) {
fireExceptionCaught(channel, t);
}
if (readBytes > 0) {
// Update the predictor.
predictor.previousReceiveBufferSize(readBytes);
// Fire the event.
fireMessageReceived(channel, buf);
}
if (ret < 0 || failure) {
close(k);
}
}
private ChannelBuffer preallocatedDirectBuffer;
private static void readIntoDirectBuffer(SelectionKey k) {
ScatteringByteChannel ch = (ScatteringByteChannel) k.channel();
NioSocketChannel channel = (NioSocketChannel) k.attachment();
ReceiveBufferSizePredictor predictor =
channel.getConfig().getReceiveBufferSizePredictor();
ChannelBuffer preallocatedDirectBuffer = channel.getWorker().preallocatedDirectBuffer;
NioWorker worker = channel.getWorker();
worker.preallocatedDirectBuffer = null;
if (preallocatedDirectBuffer == null) {
preallocatedDirectBuffer = ChannelBuffers.directBuffer(1048576);
}
int ret = 0;
int readBytes = 0;
boolean failure = true;
try {
while ((ret = preallocatedDirectBuffer.writeBytes(ch, preallocatedDirectBuffer.writableBytes())) > 0) {
readBytes += ret;
if (!preallocatedDirectBuffer.writable()) {
break;
}
}
failure = false;
} catch (AsynchronousCloseException e) {
// Can happen, and does not need a user attention.
} catch (Throwable t) {
fireExceptionCaught(channel, t);
}
if (readBytes > 0) {
// Update the predictor.
predictor.previousReceiveBufferSize(readBytes);
// Fire the event.
ChannelBuffer slice = preallocatedDirectBuffer.slice(
preallocatedDirectBuffer.readerIndex(),
preallocatedDirectBuffer.readableBytes());
preallocatedDirectBuffer.readerIndex(preallocatedDirectBuffer.writerIndex());
if (preallocatedDirectBuffer.writable()) {
worker.preallocatedDirectBuffer = preallocatedDirectBuffer;
}
fireMessageReceived(channel, slice);
} else if (readBytes == 0) {
worker.preallocatedDirectBuffer = preallocatedDirectBuffer;
}
if (ret < 0 || failure) {
close(k);
}
}
private static void write(SelectionKey k) {
NioSocketChannel ch = (NioSocketChannel) k.attachment();
write(ch, false);
}
private static void close(SelectionKey k) {
NioSocketChannel ch = (NioSocketChannel) k.attachment();
close(ch, ch.getSucceededFuture());
}
static void write(final NioSocketChannel channel, boolean mightNeedWakeup) {
if (!channel.isConnected()) {
cleanUpWriteBuffer(channel);
return;
}
if (mightNeedWakeup) {
NioWorker worker = channel.getWorker();
if (worker != null) {
Thread workerThread = worker.thread;
if (workerThread != null && Thread.currentThread() != workerThread) {
if (channel.writeTaskInTaskQueue.compareAndSet(false, true)) {
worker.writeTaskQueue.offer(channel.writeTask);
}
Selector workerSelector = worker.selector;
if (workerSelector != null) {
if (worker.wakenUp.compareAndSet(false, true)) {
workerSelector.wakeup();
}
}
return;
}
}
}
writeNow(channel, mightNeedWakeup, channel.getConfig().getWriteSpinCount());
}
private static void writeNow(NioSocketChannel channel,
boolean mightNeedWakeup, final int writeSpinCount) {
boolean open = true;
boolean addOpWrite = false;
boolean removeOpWrite = false;
MessageEvent evt;
ChannelBuffer buf;
int bufIdx;
Queue<MessageEvent> writeBuffer = channel.writeBuffer;
synchronized (channel.writeLock) {
evt = channel.currentWriteEvent;
for (;;) {
if (evt == null) {
evt = writeBuffer.poll();
if (evt == null) {
channel.currentWriteEvent = null;
removeOpWrite = true;
break;
}
buf = (ChannelBuffer) evt.getMessage();
bufIdx = buf.readerIndex();
} else {
buf = (ChannelBuffer) evt.getMessage();
bufIdx = channel.currentWriteIndex;
}
try {
for (int i = writeSpinCount; i > 0; i --) {
int localWrittenBytes = buf.getBytes(
bufIdx,
channel.socket,
buf.writerIndex() - bufIdx);
if (localWrittenBytes != 0) {
bufIdx += localWrittenBytes;
break;
}
}
if (bufIdx == buf.writerIndex()) {
// Successful write - proceed to the next message.
evt.getFuture().setSuccess();
evt = null;
} else {
// Not written fully - perhaps the kernel buffer is full.
channel.currentWriteEvent = evt;
channel.currentWriteIndex = bufIdx;
addOpWrite = true;
break;
}
} catch (AsynchronousCloseException e) {
// Doesn't need a user attention - ignore.
} catch (Throwable t) {
evt.getFuture().setFailure(t);
evt = null;
fireExceptionCaught(channel, t);
if (t instanceof IOException) {
open = false;
close(channel, channel.getSucceededFuture());
}
}
}
}
if (open) {
if (addOpWrite) {
setOpWrite(channel, true, mightNeedWakeup);
} else if (removeOpWrite) {
setOpWrite(channel, false, mightNeedWakeup);
}
fireChannelInterestChangedIfNecessary(channel, open);
}
}
private static void fireChannelInterestChangedIfNecessary(
NioSocketChannel channel, boolean open) {
if (channel.firingEvent) {
// Prevent StackOverflowError.
return;
}
channel.firingEvent = true;
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);
}
} else {
if (writable) {
fireChannelInterestChanged(channel, interestOps & ~Channel.OP_WRITE);
} else {
fireChannelInterestChanged(channel, interestOps | Channel.OP_WRITE);
}
}
} finally {
channel.firingEvent = false;
}
}
private static void setOpWrite(
NioSocketChannel channel, boolean opWrite, boolean mightNeedWakeup) {
NioWorker worker = channel.getWorker();
if (worker == null) {
IllegalStateException cause =
new IllegalStateException("Channel not connected yet (null worker)");
fireExceptionCaught(channel, cause);
return;
}
Selector selector = worker.selector;
SelectionKey key = channel.socket.keyFor(selector);
if (key == null) {
return;
}
if (!key.isValid()) {
close(key);
return;
}
int interestOps;
boolean changed = false;
// interestOps can change at any time and at any thread.
// Acquire a lock to avoid possible race condition.
synchronized (channel.interestOpsLock) {
if (opWrite) {
if (!mightNeedWakeup) {
interestOps = channel.getRawInterestOps();
if ((interestOps & SelectionKey.OP_WRITE) == 0) {
interestOps |= SelectionKey.OP_WRITE;
key.interestOps(interestOps);
changed = true;
}
} else {
switch (CONSTRAINT_LEVEL) {
case 0:
interestOps = channel.getRawInterestOps();
if ((interestOps & SelectionKey.OP_WRITE) == 0) {
interestOps |= SelectionKey.OP_WRITE;
key.interestOps(interestOps);
if (Thread.currentThread() != worker.thread &&
worker.wakenUp.compareAndSet(false, true)) {
selector.wakeup();
}
changed = true;
}
break;
case 1:
case 2:
interestOps = channel.getRawInterestOps();
if ((interestOps & SelectionKey.OP_WRITE) == 0) {
if (Thread.currentThread() == worker.thread) {
interestOps |= SelectionKey.OP_WRITE;
key.interestOps(interestOps);
changed = true;
} else {
worker.selectorGuard.readLock().lock();
try {
if (worker.wakenUp.compareAndSet(false, true)) {
selector.wakeup();
}
interestOps |= SelectionKey.OP_WRITE;
key.interestOps(interestOps);
changed = true;
} finally {
worker.selectorGuard.readLock().unlock();
}
}
}
break;
default:
throw new Error();
}
}
} else {
if (!mightNeedWakeup) {
interestOps = channel.getRawInterestOps();
if ((interestOps & SelectionKey.OP_WRITE) != 0) {
interestOps &= ~SelectionKey.OP_WRITE;
key.interestOps(interestOps);
changed = true;
}
} else {
switch (CONSTRAINT_LEVEL) {
case 0:
interestOps = channel.getRawInterestOps();
if ((interestOps & SelectionKey.OP_WRITE) != 0) {
interestOps &= ~SelectionKey.OP_WRITE;
key.interestOps(interestOps);
if (Thread.currentThread() != worker.thread &&
worker.wakenUp.compareAndSet(false, true)) {
selector.wakeup();
}
changed = true;
}
break;
case 1:
case 2:
interestOps = channel.getRawInterestOps();
if ((interestOps & SelectionKey.OP_WRITE) != 0) {
if (Thread.currentThread() == worker.thread) {
interestOps &= ~SelectionKey.OP_WRITE;
key.interestOps(interestOps);
changed = true;
} else {
worker.selectorGuard.readLock().lock();
try {
if (worker.wakenUp.compareAndSet(false, true)) {
selector.wakeup();
}
interestOps &= ~SelectionKey.OP_WRITE;
key.interestOps(interestOps);
changed = true;
} finally {
worker.selectorGuard.readLock().unlock();
}
}
}
break;
default:
throw new Error();
}
}
}
}
if (changed) {
channel.setRawInterestOpsNow(interestOps);
//fireChannelInterestChanged(channel, interestOps);
}
}
static void close(NioSocketChannel channel, ChannelFuture future) {
NioWorker worker = channel.getWorker();
if (worker != null) {
Selector selector = worker.selector;
SelectionKey key = channel.socket.keyFor(selector);
if (key != null) {
key.cancel();
}
}
boolean connected = channel.isConnected();
boolean bound = channel.isBound();
try {
channel.socket.close();
if (channel.setClosed()) {
future.setSuccess();
if (connected) {
if (channel.getRawInterestOps() != Channel.OP_WRITE) {
channel.setRawInterestOpsNow(Channel.OP_WRITE);
fireChannelInterestChanged(channel, Channel.OP_WRITE);
}
fireChannelDisconnected(channel);
}
if (bound) {
fireChannelUnbound(channel);
}
cleanUpWriteBuffer(channel);
fireChannelClosed(channel);
} else {
future.setSuccess();
}
} catch (Throwable t) {
future.setFailure(t);
fireExceptionCaught(channel, t);
}
}
private static void cleanUpWriteBuffer(NioSocketChannel channel) {
// Create the exception only once to avoid the excessive overhead
// caused by fillStackTrace.
Exception cause;
if (channel.isOpen()) {
cause = new NotYetConnectedException();
} else {
cause = new ClosedChannelException();
}
// Clean up the stale messages in the write buffer.
synchronized (channel.writeLock) {
MessageEvent evt = channel.currentWriteEvent;
if (evt != null) {
channel.currentWriteEvent = null;
channel.currentWriteIndex = 0;
evt.getFuture().setFailure(cause);
fireExceptionCaught(channel, cause);
}
Queue<MessageEvent> writeBuffer = channel.writeBuffer;
for (;;) {
evt = writeBuffer.poll();
if (evt == null) {
break;
}
evt.getFuture().setFailure(cause);
fireExceptionCaught(channel, cause);
}
}
}
static void setInterestOps(
NioSocketChannel channel, ChannelFuture future, int interestOps) {
NioWorker worker = channel.getWorker();
if (worker == null) {
IllegalStateException cause =
new IllegalStateException("Channel not connected yet (null worker)");
future.setFailure(cause);
fireExceptionCaught(channel, cause);
return;
}
Selector selector = worker.selector;
SelectionKey key = channel.socket.keyFor(selector);
if (key == null || selector == null) {
IllegalStateException cause =
new IllegalStateException("Channel not connected yet (SelectionKey not found)");
future.setFailure(cause);
fireExceptionCaught(channel, cause);
}
boolean changed = false;
try {
// interestOps can change at any time and at any thread.
// Acquire a lock to avoid possible race condition.
synchronized (channel.interestOpsLock) {
// Override OP_WRITE flag - a user cannot change this flag.
interestOps &= ~Channel.OP_WRITE;
interestOps |= channel.getRawInterestOps() & Channel.OP_WRITE;
switch (CONSTRAINT_LEVEL) {
case 0:
if (channel.getRawInterestOps() != interestOps) {
key.interestOps(interestOps);
if (Thread.currentThread() != worker.thread &&
worker.wakenUp.compareAndSet(false, true)) {
selector.wakeup();
}
changed = true;
}
break;
case 1:
case 2:
if (channel.getRawInterestOps() != interestOps) {
if (Thread.currentThread() == worker.thread) {
key.interestOps(interestOps);
changed = true;
} else {
worker.selectorGuard.readLock().lock();
try {
if (worker.wakenUp.compareAndSet(false, true)) {
selector.wakeup();
}
key.interestOps(interestOps);
changed = true;
} finally {
worker.selectorGuard.readLock().unlock();
}
}
}
break;
default:
throw new Error();
}
}
future.setSuccess();
if (changed) {
channel.setRawInterestOpsNow(interestOps);
fireChannelInterestChanged(channel, interestOps);
}
} catch (Throwable t) {
future.setFailure(t);
fireExceptionCaught(channel, t);
}
}
private final class RegisterTask implements Runnable {
private final NioSocketChannel channel;
private final ChannelFuture future;
private final boolean server;
RegisterTask(
NioSocketChannel channel, ChannelFuture future, boolean server) {
this.channel = channel;
this.future = future;
this.server = server;
}
public void run() {
try {
channel.socket.register(selector, SelectionKey.OP_READ, channel);
if (future != null) {
future.setSuccess();
}
} catch (ClosedChannelException e) {
future.setFailure(e);
throw new ChannelException(
"Failed to register a socket to the selector.", e);
}
if (server) {
fireChannelOpen(channel);
fireChannelBound(channel, channel.getLocalAddress());
} else if (!((NioClientSocketChannel) channel).boundManually) {
fireChannelBound(channel, channel.getLocalAddress());
}
fireChannelConnected(channel, channel.getRemoteAddress());
}
}
}