b3d3269b8c
Motivation: Overspecifying interfaces can increase coupling and make refactoring harder down the line. Modification: Places that were specifying fields, variables, and return types as ScheduledFuture, but did not use any features specific to ScheduledFuture, have been changed to specify Future instead. Result: Cleaner code.
513 lines
18 KiB
Java
513 lines
18 KiB
Java
/*
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* Copyright 2012 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.channel.nio;
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import io.netty.buffer.ByteBuf;
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import io.netty.buffer.ByteBufAllocator;
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import io.netty.buffer.ByteBufUtil;
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import io.netty.buffer.Unpooled;
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import io.netty.channel.AbstractChannel;
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import io.netty.channel.Channel;
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import io.netty.channel.ChannelException;
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import io.netty.channel.ChannelFuture;
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import io.netty.channel.ChannelFutureListener;
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import io.netty.channel.ChannelPromise;
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import io.netty.channel.ConnectTimeoutException;
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import io.netty.channel.EventLoop;
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import io.netty.util.ReferenceCountUtil;
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import io.netty.util.ReferenceCounted;
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import io.netty.util.concurrent.Future;
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import io.netty.util.internal.logging.InternalLogger;
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import io.netty.util.internal.logging.InternalLoggerFactory;
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import java.io.IOException;
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import java.net.SocketAddress;
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import java.nio.channels.CancelledKeyException;
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import java.nio.channels.ClosedChannelException;
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import java.nio.channels.ConnectionPendingException;
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import java.nio.channels.SelectableChannel;
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import java.nio.channels.SelectionKey;
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import java.util.concurrent.TimeUnit;
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/**
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* Abstract base class for {@link Channel} implementations which use a Selector based approach.
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*/
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public abstract class AbstractNioChannel extends AbstractChannel {
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private static final InternalLogger logger =
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InternalLoggerFactory.getInstance(AbstractNioChannel.class);
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private final SelectableChannel ch;
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protected final int readInterestOp;
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volatile SelectionKey selectionKey;
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boolean readPending;
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private final Runnable clearReadPendingRunnable = new Runnable() {
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@Override
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public void run() {
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clearReadPending0();
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}
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};
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/**
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* The future of the current connection attempt. If not null, subsequent
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* connection attempts will fail.
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*/
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private ChannelPromise connectPromise;
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private Future<?> connectTimeoutFuture;
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private SocketAddress requestedRemoteAddress;
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/**
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* Create a new instance
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*
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* @param parent the parent {@link Channel} by which this instance was created. May be {@code null}
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* @param ch the underlying {@link SelectableChannel} on which it operates
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* @param readInterestOp the ops to set to receive data from the {@link SelectableChannel}
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*/
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protected AbstractNioChannel(Channel parent, SelectableChannel ch, int readInterestOp) {
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super(parent);
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this.ch = ch;
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this.readInterestOp = readInterestOp;
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try {
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ch.configureBlocking(false);
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} catch (IOException e) {
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try {
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ch.close();
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} catch (IOException e2) {
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logger.warn(
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"Failed to close a partially initialized socket.", e2);
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}
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throw new ChannelException("Failed to enter non-blocking mode.", e);
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}
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}
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@Override
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public boolean isOpen() {
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return ch.isOpen();
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}
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@Override
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public NioUnsafe unsafe() {
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return (NioUnsafe) super.unsafe();
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}
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protected SelectableChannel javaChannel() {
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return ch;
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}
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@Override
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public NioEventLoop eventLoop() {
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return (NioEventLoop) super.eventLoop();
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}
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/**
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* Return the current {@link SelectionKey}
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*/
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protected SelectionKey selectionKey() {
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assert selectionKey != null;
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return selectionKey;
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}
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/**
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* @deprecated No longer supported.
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* No longer supported.
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*/
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@Deprecated
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protected boolean isReadPending() {
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return readPending;
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}
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/**
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* @deprecated Use {@link #clearReadPending()} if appropriate instead.
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* No longer supported.
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*/
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@Deprecated
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protected void setReadPending(final boolean readPending) {
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if (isRegistered()) {
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EventLoop eventLoop = eventLoop();
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if (eventLoop.inEventLoop()) {
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setReadPending0(readPending);
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} else {
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eventLoop.execute(new Runnable() {
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@Override
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public void run() {
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setReadPending0(readPending);
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}
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});
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}
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} else {
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// Best effort if we are not registered yet clear readPending.
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// NB: We only set the boolean field instead of calling clearReadPending0(), because the SelectionKey is
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// not set yet so it would produce an assertion failure.
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this.readPending = readPending;
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}
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}
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/**
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* Set read pending to {@code false}.
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*/
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protected final void clearReadPending() {
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if (isRegistered()) {
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EventLoop eventLoop = eventLoop();
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if (eventLoop.inEventLoop()) {
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clearReadPending0();
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} else {
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eventLoop.execute(clearReadPendingRunnable);
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}
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} else {
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// Best effort if we are not registered yet clear readPending. This happens during channel initialization.
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// NB: We only set the boolean field instead of calling clearReadPending0(), because the SelectionKey is
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// not set yet so it would produce an assertion failure.
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readPending = false;
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}
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}
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private void setReadPending0(boolean readPending) {
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this.readPending = readPending;
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if (!readPending) {
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((AbstractNioUnsafe) unsafe()).removeReadOp();
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}
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}
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private void clearReadPending0() {
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readPending = false;
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((AbstractNioUnsafe) unsafe()).removeReadOp();
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}
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/**
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* Special {@link Unsafe} sub-type which allows to access the underlying {@link SelectableChannel}
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*/
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public interface NioUnsafe extends Unsafe {
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/**
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* Return underlying {@link SelectableChannel}
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*/
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SelectableChannel ch();
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/**
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* Finish connect
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*/
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void finishConnect();
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/**
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* Read from underlying {@link SelectableChannel}
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*/
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void read();
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void forceFlush();
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}
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protected abstract class AbstractNioUnsafe extends AbstractUnsafe implements NioUnsafe {
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protected final void removeReadOp() {
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SelectionKey key = selectionKey();
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// Check first if the key is still valid as it may be canceled as part of the deregistration
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// from the EventLoop
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// See https://github.com/netty/netty/issues/2104
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if (!key.isValid()) {
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return;
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}
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int interestOps = key.interestOps();
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if ((interestOps & readInterestOp) != 0) {
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// only remove readInterestOp if needed
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key.interestOps(interestOps & ~readInterestOp);
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}
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}
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@Override
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public final SelectableChannel ch() {
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return javaChannel();
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}
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@Override
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public final void connect(
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final SocketAddress remoteAddress, final SocketAddress localAddress, final ChannelPromise promise) {
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if (!promise.setUncancellable() || !ensureOpen(promise)) {
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return;
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}
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try {
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if (connectPromise != null) {
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// Already a connect in process.
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throw new ConnectionPendingException();
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}
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boolean wasActive = isActive();
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if (doConnect(remoteAddress, localAddress)) {
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fulfillConnectPromise(promise, wasActive);
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} else {
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connectPromise = promise;
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requestedRemoteAddress = remoteAddress;
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// Schedule connect timeout.
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int connectTimeoutMillis = config().getConnectTimeoutMillis();
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if (connectTimeoutMillis > 0) {
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connectTimeoutFuture = eventLoop().schedule(new Runnable() {
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@Override
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public void run() {
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ChannelPromise connectPromise = AbstractNioChannel.this.connectPromise;
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if (connectPromise != null && !connectPromise.isDone()
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&& connectPromise.tryFailure(new ConnectTimeoutException(
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"connection timed out: " + remoteAddress))) {
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close(voidPromise());
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}
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}
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}, connectTimeoutMillis, TimeUnit.MILLISECONDS);
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}
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promise.addListener(new ChannelFutureListener() {
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@Override
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public void operationComplete(ChannelFuture future) throws Exception {
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if (future.isCancelled()) {
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if (connectTimeoutFuture != null) {
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connectTimeoutFuture.cancel(false);
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}
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connectPromise = null;
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close(voidPromise());
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}
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}
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});
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}
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} catch (Throwable t) {
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promise.tryFailure(annotateConnectException(t, remoteAddress));
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closeIfClosed();
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}
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}
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private void fulfillConnectPromise(ChannelPromise promise, boolean wasActive) {
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if (promise == null) {
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// Closed via cancellation and the promise has been notified already.
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return;
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}
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// Get the state as trySuccess() may trigger an ChannelFutureListener that will close the Channel.
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// We still need to ensure we call fireChannelActive() in this case.
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boolean active = isActive();
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// trySuccess() will return false if a user cancelled the connection attempt.
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boolean promiseSet = promise.trySuccess();
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// Regardless if the connection attempt was cancelled, channelActive() event should be triggered,
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// because what happened is what happened.
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if (!wasActive && active) {
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pipeline().fireChannelActive();
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}
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// If a user cancelled the connection attempt, close the channel, which is followed by channelInactive().
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if (!promiseSet) {
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close(voidPromise());
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}
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}
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private void fulfillConnectPromise(ChannelPromise promise, Throwable cause) {
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if (promise == null) {
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// Closed via cancellation and the promise has been notified already.
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return;
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}
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// Use tryFailure() instead of setFailure() to avoid the race against cancel().
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promise.tryFailure(cause);
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closeIfClosed();
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}
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@Override
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public final void finishConnect() {
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// Note this method is invoked by the event loop only if the connection attempt was
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// neither cancelled nor timed out.
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assert eventLoop().inEventLoop();
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try {
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boolean wasActive = isActive();
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doFinishConnect();
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fulfillConnectPromise(connectPromise, wasActive);
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} catch (Throwable t) {
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fulfillConnectPromise(connectPromise, annotateConnectException(t, requestedRemoteAddress));
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} finally {
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// Check for null as the connectTimeoutFuture is only created if a connectTimeoutMillis > 0 is used
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// See https://github.com/netty/netty/issues/1770
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if (connectTimeoutFuture != null) {
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connectTimeoutFuture.cancel(false);
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}
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connectPromise = null;
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}
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}
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@Override
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protected final void flush0() {
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// Flush immediately only when there's no pending flush.
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// If there's a pending flush operation, event loop will call forceFlush() later,
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// and thus there's no need to call it now.
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if (!isFlushPending()) {
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super.flush0();
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}
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}
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@Override
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public final void forceFlush() {
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// directly call super.flush0() to force a flush now
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super.flush0();
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}
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private boolean isFlushPending() {
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SelectionKey selectionKey = selectionKey();
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return selectionKey.isValid() && (selectionKey.interestOps() & SelectionKey.OP_WRITE) != 0;
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}
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}
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@Override
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protected boolean isCompatible(EventLoop loop) {
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return loop instanceof NioEventLoop;
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}
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@Override
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protected void doRegister() throws Exception {
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boolean selected = false;
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for (;;) {
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try {
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selectionKey = javaChannel().register(eventLoop().unwrappedSelector(), 0, this);
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return;
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} catch (CancelledKeyException e) {
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if (!selected) {
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// Force the Selector to select now as the "canceled" SelectionKey may still be
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// cached and not removed because no Select.select(..) operation was called yet.
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eventLoop().selectNow();
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selected = true;
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} else {
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// We forced a select operation on the selector before but the SelectionKey is still cached
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// for whatever reason. JDK bug ?
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throw e;
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}
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}
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}
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}
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@Override
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protected void doDeregister() throws Exception {
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eventLoop().cancel(selectionKey());
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}
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@Override
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protected void doBeginRead() throws Exception {
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// Channel.read() or ChannelHandlerContext.read() was called
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final SelectionKey selectionKey = this.selectionKey;
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if (!selectionKey.isValid()) {
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return;
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}
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readPending = true;
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final int interestOps = selectionKey.interestOps();
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if ((interestOps & readInterestOp) == 0) {
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selectionKey.interestOps(interestOps | readInterestOp);
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}
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}
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/**
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* Connect to the remote peer
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*/
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protected abstract boolean doConnect(SocketAddress remoteAddress, SocketAddress localAddress) throws Exception;
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/**
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* Finish the connect
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*/
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protected abstract void doFinishConnect() throws Exception;
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/**
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* Returns an off-heap copy of the specified {@link ByteBuf}, and releases the original one.
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* Note that this method does not create an off-heap copy if the allocation / deallocation cost is too high,
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* but just returns the original {@link ByteBuf}..
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*/
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protected final ByteBuf newDirectBuffer(ByteBuf buf) {
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final int readableBytes = buf.readableBytes();
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if (readableBytes == 0) {
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ReferenceCountUtil.safeRelease(buf);
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return Unpooled.EMPTY_BUFFER;
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}
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final ByteBufAllocator alloc = alloc();
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if (alloc.isDirectBufferPooled()) {
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ByteBuf directBuf = alloc.directBuffer(readableBytes);
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directBuf.writeBytes(buf, buf.readerIndex(), readableBytes);
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ReferenceCountUtil.safeRelease(buf);
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return directBuf;
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}
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final ByteBuf directBuf = ByteBufUtil.threadLocalDirectBuffer();
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if (directBuf != null) {
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directBuf.writeBytes(buf, buf.readerIndex(), readableBytes);
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ReferenceCountUtil.safeRelease(buf);
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return directBuf;
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}
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// Allocating and deallocating an unpooled direct buffer is very expensive; give up.
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return buf;
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}
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/**
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* Returns an off-heap copy of the specified {@link ByteBuf}, and releases the specified holder.
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* The caller must ensure that the holder releases the original {@link ByteBuf} when the holder is released by
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* this method. Note that this method does not create an off-heap copy if the allocation / deallocation cost is
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* too high, but just returns the original {@link ByteBuf}..
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*/
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protected final ByteBuf newDirectBuffer(ReferenceCounted holder, ByteBuf buf) {
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final int readableBytes = buf.readableBytes();
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if (readableBytes == 0) {
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ReferenceCountUtil.safeRelease(holder);
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return Unpooled.EMPTY_BUFFER;
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}
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final ByteBufAllocator alloc = alloc();
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if (alloc.isDirectBufferPooled()) {
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ByteBuf directBuf = alloc.directBuffer(readableBytes);
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directBuf.writeBytes(buf, buf.readerIndex(), readableBytes);
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ReferenceCountUtil.safeRelease(holder);
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return directBuf;
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}
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final ByteBuf directBuf = ByteBufUtil.threadLocalDirectBuffer();
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if (directBuf != null) {
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directBuf.writeBytes(buf, buf.readerIndex(), readableBytes);
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ReferenceCountUtil.safeRelease(holder);
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return directBuf;
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}
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// Allocating and deallocating an unpooled direct buffer is very expensive; give up.
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if (holder != buf) {
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// Ensure to call holder.release() to give the holder a chance to release other resources than its content.
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buf.retain();
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ReferenceCountUtil.safeRelease(holder);
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}
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return buf;
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}
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@Override
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protected void doClose() throws Exception {
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ChannelPromise promise = connectPromise;
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if (promise != null) {
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// Use tryFailure() instead of setFailure() to avoid the race against cancel().
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promise.tryFailure(new ClosedChannelException());
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connectPromise = null;
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}
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Future<?> future = connectTimeoutFuture;
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if (future != null) {
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future.cancel(false);
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connectTimeoutFuture = null;
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}
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}
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}
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