io.netty.channel.nio.AbstractNioChannel Maven / Gradle / Ivy
/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you 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:
*
* https://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 io.netty.channel.nio;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.ByteBufUtil;
import io.netty.buffer.Unpooled;
import io.netty.channel.AbstractChannel;
import io.netty.channel.Channel;
import io.netty.channel.ChannelException;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelPromise;
import io.netty.channel.ConnectTimeoutException;
import io.netty.channel.EventLoop;
import io.netty.channel.IoEvent;
import io.netty.channel.IoEventLoop;
import io.netty.channel.IoEventLoopGroup;
import io.netty.channel.IoRegistration;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.ReferenceCounted;
import io.netty.util.concurrent.Future;
import io.netty.util.internal.ObjectUtil;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.io.IOException;
import java.net.SocketAddress;
import java.nio.channels.CancelledKeyException;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.ConnectionPendingException;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SelectionKey;
import java.util.concurrent.TimeUnit;
/**
* Abstract base class for {@link Channel} implementations which use a Selector based approach.
*/
public abstract class AbstractNioChannel extends AbstractChannel {
private static final InternalLogger logger =
InternalLoggerFactory.getInstance(AbstractNioChannel.class);
private final SelectableChannel ch;
protected final int readInterestOp;
protected final NioIoOps readOps;
volatile NioIoRegistration registration;
boolean readPending;
private final Runnable clearReadPendingRunnable = new Runnable() {
@Override
public void run() {
clearReadPending0();
}
};
/**
* The future of the current connection attempt. If not null, subsequent
* connection attempts will fail.
*/
private ChannelPromise connectPromise;
private Future connectTimeoutFuture;
private SocketAddress requestedRemoteAddress;
/**
* Create a new instance
*
* @param parent the parent {@link Channel} by which this instance was created. May be {@code null}
* @param ch the underlying {@link SelectableChannel} on which it operates
* @param readOps the ops to set to receive data from the {@link SelectableChannel}
*/
protected AbstractNioChannel(Channel parent, SelectableChannel ch, int readOps) {
this(parent, ch, NioIoOps.valueOf(readOps));
}
protected AbstractNioChannel(Channel parent, SelectableChannel ch, NioIoOps readOps) {
super(parent);
this.ch = ch;
this.readInterestOp = ObjectUtil.checkNotNull(readOps, "readOps").value;
this.readOps = readOps;
try {
ch.configureBlocking(false);
} catch (IOException e) {
try {
ch.close();
} catch (IOException e2) {
logger.warn(
"Failed to close a partially initialized socket.", e2);
}
throw new ChannelException("Failed to enter non-blocking mode.", e);
}
}
protected void addAndSubmit(NioIoOps addOps) {
int interestOps = selectionKey().interestOps();
if (!addOps.isIncludedIn(interestOps)) {
try {
registration().submit(NioIoOps.valueOf(interestOps).with(addOps));
} catch (Exception e) {
throw new ChannelException(e);
}
}
}
protected void removeAndSubmit(NioIoOps removeOps) {
int interestOps = selectionKey().interestOps();
if (removeOps.isIncludedIn(interestOps)) {
try {
registration().submit(NioIoOps.valueOf(interestOps).without(removeOps));
} catch (Exception e) {
throw new ChannelException(e);
}
}
}
@Override
public boolean isOpen() {
return ch.isOpen();
}
@Override
public NioUnsafe unsafe() {
return (NioUnsafe) super.unsafe();
}
protected SelectableChannel javaChannel() {
return ch;
}
/**
* Return the current {@link SelectionKey}
*
* @deprecated use {@link #registration}.
*/
@Deprecated
protected SelectionKey selectionKey() {
return registration().selectionKey();
}
@SuppressWarnings("unchecked")
protected NioIoRegistration registration() {
assert registration != null;
return registration;
}
/**
* @deprecated No longer supported.
* No longer supported.
*/
@Deprecated
protected boolean isReadPending() {
return readPending;
}
/**
* @deprecated Use {@link #clearReadPending()} if appropriate instead.
* No longer supported.
*/
@Deprecated
protected void setReadPending(final boolean readPending) {
if (isRegistered()) {
EventLoop eventLoop = eventLoop();
if (eventLoop.inEventLoop()) {
setReadPending0(readPending);
} else {
eventLoop.execute(new Runnable() {
@Override
public void run() {
setReadPending0(readPending);
}
});
}
} else {
// Best effort if we are not registered yet clear readPending.
// NB: We only set the boolean field instead of calling clearReadPending0(), because the SelectionKey is
// not set yet so it would produce an assertion failure.
this.readPending = readPending;
}
}
/**
* Set read pending to {@code false}.
*/
protected final void clearReadPending() {
if (isRegistered()) {
EventLoop eventLoop = eventLoop();
if (eventLoop.inEventLoop()) {
clearReadPending0();
} else {
eventLoop.execute(clearReadPendingRunnable);
}
} else {
// Best effort if we are not registered yet clear readPending. This happens during channel initialization.
// NB: We only set the boolean field instead of calling clearReadPending0(), because the SelectionKey is
// not set yet so it would produce an assertion failure.
readPending = false;
}
}
private void setReadPending0(boolean readPending) {
this.readPending = readPending;
if (!readPending) {
((AbstractNioUnsafe) unsafe()).removeReadOp();
}
}
private void clearReadPending0() {
readPending = false;
((AbstractNioUnsafe) unsafe()).removeReadOp();
}
/**
* Special {@link Unsafe} sub-type which allows to access the underlying {@link SelectableChannel}
*/
public interface NioUnsafe extends Unsafe {
/**
* Return underlying {@link SelectableChannel}
*/
SelectableChannel ch();
/**
* Finish connect
*/
void finishConnect();
/**
* Read from underlying {@link SelectableChannel}
*/
void read();
void forceFlush();
}
protected abstract class AbstractNioUnsafe extends AbstractUnsafe implements NioUnsafe, NioIoHandle {
@Override
public void close() {
close(voidPromise());
}
@Override
public SelectableChannel selectableChannel() {
return ch();
}
Channel channel() {
return AbstractNioChannel.this;
}
protected final void removeReadOp() {
NioIoRegistration registration = registration();
// Check first if the key is still valid as it may be canceled as part of the deregistration
// from the EventLoop
// See https://github.com/netty/netty/issues/2104
if (!registration.isValid()) {
return;
}
removeAndSubmit(readOps);
}
@Override
public final SelectableChannel ch() {
return javaChannel();
}
@Override
public final void connect(
final SocketAddress remoteAddress, final SocketAddress localAddress, final ChannelPromise promise) {
// Don't mark the connect promise as uncancellable as in fact we can cancel it as it is using
// non-blocking io.
if (promise.isDone() || !ensureOpen(promise)) {
return;
}
try {
if (connectPromise != null) {
// Already a connect in process.
throw new ConnectionPendingException();
}
boolean wasActive = isActive();
if (doConnect(remoteAddress, localAddress)) {
fulfillConnectPromise(promise, wasActive);
} else {
connectPromise = promise;
requestedRemoteAddress = remoteAddress;
// Schedule connect timeout.
final int connectTimeoutMillis = config().getConnectTimeoutMillis();
if (connectTimeoutMillis > 0) {
connectTimeoutFuture = eventLoop().schedule(new Runnable() {
@Override
public void run() {
ChannelPromise connectPromise = AbstractNioChannel.this.connectPromise;
if (connectPromise != null && !connectPromise.isDone()
&& connectPromise.tryFailure(new ConnectTimeoutException(
"connection timed out after " + connectTimeoutMillis + " ms: " +
remoteAddress))) {
close(voidPromise());
}
}
}, connectTimeoutMillis, TimeUnit.MILLISECONDS);
}
promise.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) {
// If the connect future is cancelled we also cancel the timeout and close the
// underlying socket.
if (future.isCancelled()) {
if (connectTimeoutFuture != null) {
connectTimeoutFuture.cancel(false);
}
connectPromise = null;
close(voidPromise());
}
}
});
}
} catch (Throwable t) {
promise.tryFailure(annotateConnectException(t, remoteAddress));
closeIfClosed();
}
}
private void fulfillConnectPromise(ChannelPromise promise, boolean wasActive) {
if (promise == null) {
// Closed via cancellation and the promise has been notified already.
return;
}
// Get the state as trySuccess() may trigger an ChannelFutureListener that will close the Channel.
// We still need to ensure we call fireChannelActive() in this case.
boolean active = isActive();
// trySuccess() will return false if a user cancelled the connection attempt.
boolean promiseSet = promise.trySuccess();
// Regardless if the connection attempt was cancelled, channelActive() event should be triggered,
// because what happened is what happened.
if (!wasActive && active) {
pipeline().fireChannelActive();
}
// If a user cancelled the connection attempt, close the channel, which is followed by channelInactive().
if (!promiseSet) {
close(voidPromise());
}
}
private void fulfillConnectPromise(ChannelPromise promise, Throwable cause) {
if (promise == null) {
// Closed via cancellation and the promise has been notified already.
return;
}
// Use tryFailure() instead of setFailure() to avoid the race against cancel().
promise.tryFailure(cause);
closeIfClosed();
}
@Override
public final void finishConnect() {
// Note this method is invoked by the event loop only if the connection attempt was
// neither cancelled nor timed out.
assert eventLoop().inEventLoop();
try {
boolean wasActive = isActive();
doFinishConnect();
fulfillConnectPromise(connectPromise, wasActive);
} catch (Throwable t) {
fulfillConnectPromise(connectPromise, annotateConnectException(t, requestedRemoteAddress));
} finally {
// Check for null as the connectTimeoutFuture is only created if a connectTimeoutMillis > 0 is used
// See https://github.com/netty/netty/issues/1770
if (connectTimeoutFuture != null) {
connectTimeoutFuture.cancel(false);
}
connectPromise = null;
}
}
@Override
protected final void flush0() {
// Flush immediately only when there's no pending flush.
// If there's a pending flush operation, event loop will call forceFlush() later,
// and thus there's no need to call it now.
if (!isFlushPending()) {
super.flush0();
}
}
@Override
public final void forceFlush() {
// directly call super.flush0() to force a flush now
super.flush0();
}
private boolean isFlushPending() {
NioIoRegistration registration = registration();
return registration.isValid() && NioIoOps.WRITE.isIncludedIn(registration.selectionKey().interestOps());
}
@Override
public void handle(IoRegistration registration, IoEvent event) {
try {
NioIoRegistration nioRegistration = (NioIoRegistration) registration;
NioIoEvent nioEvent = (NioIoEvent) event;
NioIoOps nioReadyOps = nioEvent.ops();
// We first need to call finishConnect() before try to trigger a read(...) or write(...) as otherwise
// the NIO JDK channel implementation may throw a NotYetConnectedException.
if (nioReadyOps.contains(NioIoOps.CONNECT)) {
// remove OP_CONNECT as otherwise Selector.select(..) will always return without blocking
// See https://github.com/netty/netty/issues/924
removeAndSubmit(NioIoOps.CONNECT);
unsafe().finishConnect();
}
// Process OP_WRITE first as we may be able to write some queued buffers and so free memory.
if (nioReadyOps.contains(NioIoOps.WRITE)) {
// Call forceFlush which will also take care of clear the OP_WRITE once there is nothing left to
// write
forceFlush();
}
// Also check for readOps of 0 to workaround possible JDK bug which may otherwise lead
// to a spin loop
if (nioReadyOps.contains(NioIoOps.READ_AND_ACCEPT) || nioReadyOps.equals(NioIoOps.NONE)) {
read();
}
} catch (CancelledKeyException ignored) {
close(voidPromise());
}
}
}
@Override
protected boolean isCompatible(EventLoop loop) {
return loop instanceof IoEventLoop && ((IoEventLoopGroup) loop).isCompatible(AbstractNioUnsafe.class);
}
@SuppressWarnings("unchecked")
@Override
protected void doRegister(ChannelPromise promise) {
assert registration == null;
((IoEventLoop) eventLoop()).register((AbstractNioUnsafe) unsafe()).addListener(f -> {
if (f.isSuccess()) {
registration = (NioIoRegistration) f.getNow();
promise.setSuccess();
} else {
promise.setFailure(f.cause());
}
});
}
@Override
protected void doDeregister() throws Exception {
NioIoRegistration registration = this.registration;
if (registration != null) {
this.registration = null;
registration.cancel();
}
}
@Override
protected void doBeginRead() throws Exception {
// Channel.read() or ChannelHandlerContext.read() was called
NioIoRegistration registration = registration();
if (registration == null || !registration.isValid()) {
return;
}
readPending = true;
addAndSubmit(readOps);
}
/**
* Connect to the remote peer
*/
protected abstract boolean doConnect(SocketAddress remoteAddress, SocketAddress localAddress) throws Exception;
/**
* Finish the connect
*/
protected abstract void doFinishConnect() throws Exception;
/**
* Returns an off-heap copy of the specified {@link ByteBuf}, and releases the original one.
* Note that this method does not create an off-heap copy if the allocation / deallocation cost is too high,
* but just returns the original {@link ByteBuf}..
*/
protected final ByteBuf newDirectBuffer(ByteBuf buf) {
final int readableBytes = buf.readableBytes();
if (readableBytes == 0) {
ReferenceCountUtil.safeRelease(buf);
return Unpooled.EMPTY_BUFFER;
}
final ByteBufAllocator alloc = alloc();
if (alloc.isDirectBufferPooled()) {
ByteBuf directBuf = alloc.directBuffer(readableBytes);
directBuf.writeBytes(buf, buf.readerIndex(), readableBytes);
ReferenceCountUtil.safeRelease(buf);
return directBuf;
}
final ByteBuf directBuf = ByteBufUtil.threadLocalDirectBuffer();
if (directBuf != null) {
directBuf.writeBytes(buf, buf.readerIndex(), readableBytes);
ReferenceCountUtil.safeRelease(buf);
return directBuf;
}
// Allocating and deallocating an unpooled direct buffer is very expensive; give up.
return buf;
}
/**
* Returns an off-heap copy of the specified {@link ByteBuf}, and releases the specified holder.
* The caller must ensure that the holder releases the original {@link ByteBuf} when the holder is released by
* this method. Note that this method does not create an off-heap copy if the allocation / deallocation cost is
* too high, but just returns the original {@link ByteBuf}..
*/
protected final ByteBuf newDirectBuffer(ReferenceCounted holder, ByteBuf buf) {
final int readableBytes = buf.readableBytes();
if (readableBytes == 0) {
ReferenceCountUtil.safeRelease(holder);
return Unpooled.EMPTY_BUFFER;
}
final ByteBufAllocator alloc = alloc();
if (alloc.isDirectBufferPooled()) {
ByteBuf directBuf = alloc.directBuffer(readableBytes);
directBuf.writeBytes(buf, buf.readerIndex(), readableBytes);
ReferenceCountUtil.safeRelease(holder);
return directBuf;
}
final ByteBuf directBuf = ByteBufUtil.threadLocalDirectBuffer();
if (directBuf != null) {
directBuf.writeBytes(buf, buf.readerIndex(), readableBytes);
ReferenceCountUtil.safeRelease(holder);
return directBuf;
}
// Allocating and deallocating an unpooled direct buffer is very expensive; give up.
if (holder != buf) {
// Ensure to call holder.release() to give the holder a chance to release other resources than its content.
buf.retain();
ReferenceCountUtil.safeRelease(holder);
}
return buf;
}
@Override
protected void doClose() throws Exception {
ChannelPromise promise = connectPromise;
if (promise != null) {
// Use tryFailure() instead of setFailure() to avoid the race against cancel().
promise.tryFailure(new ClosedChannelException());
connectPromise = null;
}
Future future = connectTimeoutFuture;
if (future != null) {
future.cancel(false);
connectTimeoutFuture = null;
}
}
}
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