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/*
* 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:
*
* 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.glowroot.shaded.netty.handler.timeout;
import org.glowroot.shaded.netty.bootstrap.ServerBootstrap;
import org.glowroot.shaded.netty.channel.Channel;
import org.glowroot.shaded.netty.channel.ChannelDuplexHandler;
import org.glowroot.shaded.netty.channel.ChannelHandlerContext;
import org.glowroot.shaded.netty.channel.ChannelInboundHandlerAdapter;
import org.glowroot.shaded.netty.channel.ChannelInitializer;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
/**
* Raises a {@link ReadTimeoutException} when no data was read within a certain
* period of time.
*
*
* // The connection is closed when there is no inbound traffic
* // for 30 seconds.
*
* public class MyChannelInitializer extends {@link ChannelInitializer}<{@link Channel}> {
* public void initChannel({@link Channel} channel) {
* channel.pipeline().addLast("readTimeoutHandler", new {@link ReadTimeoutHandler}(30);
* channel.pipeline().addLast("myHandler", new MyHandler());
* }
* }
*
* // Handler should handle the {@link ReadTimeoutException}.
* public class MyHandler extends {@link ChannelDuplexHandler} {
* {@code @Override}
* public void exceptionCaught({@link ChannelHandlerContext} ctx, {@link Throwable} cause)
* throws {@link Exception} {
* if (cause instanceof {@link ReadTimeoutException}) {
* // do something
* } else {
* super.exceptionCaught(ctx, cause);
* }
* }
* }
*
* {@link ServerBootstrap} bootstrap = ...;
* ...
* bootstrap.childHandler(new MyChannelInitializer());
* ...
*
* @see WriteTimeoutHandler
* @see IdleStateHandler
*/
public class ReadTimeoutHandler extends ChannelInboundHandlerAdapter {
private static final long MIN_TIMEOUT_NANOS = TimeUnit.MILLISECONDS.toNanos(1);
private final long timeoutNanos;
private long lastReadTime;
private volatile ScheduledFuture timeout;
private volatile int state; // 0 - none, 1 - Initialized, 2 - Destroyed;
private volatile boolean reading;
private boolean closed;
/**
* Creates a new instance.
*
* @param timeoutSeconds
* read timeout in seconds
*/
public ReadTimeoutHandler(int timeoutSeconds) {
this(timeoutSeconds, TimeUnit.SECONDS);
}
/**
* Creates a new instance.
*
* @param timeout
* read timeout
* @param unit
* the {@link TimeUnit} of {@code timeout}
*/
public ReadTimeoutHandler(long timeout, TimeUnit unit) {
if (unit == null) {
throw new NullPointerException("unit");
}
if (timeout <= 0) {
timeoutNanos = 0;
} else {
timeoutNanos = Math.max(unit.toNanos(timeout), MIN_TIMEOUT_NANOS);
}
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
if (ctx.channel().isActive() && ctx.channel().isRegistered()) {
// channelActvie() event has been fired already, which means this.channelActive() will
// not be invoked. We have to initialize here instead.
initialize(ctx);
} else {
// channelActive() event has not been fired yet. this.channelActive() will be invoked
// and initialization will occur there.
}
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
destroy();
}
@Override
public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
// Initialize early if channel is active already.
if (ctx.channel().isActive()) {
initialize(ctx);
}
super.channelRegistered(ctx);
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
// This method will be invoked only if this handler was added
// before channelActive() event is fired. If a user adds this handler
// after the channelActive() event, initialize() will be called by beforeAdd().
initialize(ctx);
super.channelActive(ctx);
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
destroy();
super.channelInactive(ctx);
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
reading = true;
ctx.fireChannelRead(msg);
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
lastReadTime = System.nanoTime();
reading = false;
ctx.fireChannelReadComplete();
}
private void initialize(ChannelHandlerContext ctx) {
// Avoid the case where destroy() is called before scheduling timeouts.
// See: https://github.com/netty/netty/issues/143
switch (state) {
case 1:
case 2:
return;
}
state = 1;
lastReadTime = System.nanoTime();
if (timeoutNanos > 0) {
timeout = ctx.executor().schedule(
new ReadTimeoutTask(ctx),
timeoutNanos, TimeUnit.NANOSECONDS);
}
}
private void destroy() {
state = 2;
if (timeout != null) {
timeout.cancel(false);
timeout = null;
}
}
/**
* Is called when a read timeout was detected.
*/
protected void readTimedOut(ChannelHandlerContext ctx) throws Exception {
if (!closed) {
ctx.fireExceptionCaught(ReadTimeoutException.INSTANCE);
ctx.close();
closed = true;
}
}
private final class ReadTimeoutTask implements Runnable {
private final ChannelHandlerContext ctx;
ReadTimeoutTask(ChannelHandlerContext ctx) {
this.ctx = ctx;
}
@Override
public void run() {
if (!ctx.channel().isOpen()) {
return;
}
long nextDelay = timeoutNanos;
if (!reading) {
nextDelay -= System.nanoTime() - lastReadTime;
}
if (nextDelay <= 0) {
// Read timed out - set a new timeout and notify the callback.
timeout = ctx.executor().schedule(this, timeoutNanos, TimeUnit.NANOSECONDS);
try {
readTimedOut(ctx);
} catch (Throwable t) {
ctx.fireExceptionCaught(t);
}
} else {
// Read occurred before the timeout - set a new timeout with shorter delay.
timeout = ctx.executor().schedule(this, nextDelay, TimeUnit.NANOSECONDS);
}
}
}
}