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io.netty.channel.local.LocalChannel 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.local;
import io.netty.buffer.ByteBuf;
import io.netty.channel.AbstractChannel;
import io.netty.channel.Channel;
import io.netty.channel.ChannelConfig;
import io.netty.channel.ChannelMetadata;
import io.netty.channel.ChannelOutboundBuffer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.ChannelPromise;
import io.netty.channel.DefaultChannelConfig;
import io.netty.channel.EventLoop;
import io.netty.channel.PreferHeapByteBufAllocator;
import io.netty.channel.RecvByteBufAllocator;
import io.netty.channel.SingleThreadEventLoop;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.concurrent.Future;
import io.netty.util.concurrent.SingleThreadEventExecutor;
import io.netty.util.internal.InternalThreadLocalMap;
import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.net.ConnectException;
import java.net.SocketAddress;
import java.nio.channels.AlreadyConnectedException;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.ConnectionPendingException;
import java.nio.channels.NotYetConnectedException;
import java.util.Queue;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
/**
* A {@link Channel} for the local transport.
*/
public class LocalChannel extends AbstractChannel {
private static final InternalLogger logger = InternalLoggerFactory.getInstance(LocalChannel.class);
@SuppressWarnings({ "rawtypes" })
private static final AtomicReferenceFieldUpdater FINISH_READ_FUTURE_UPDATER =
AtomicReferenceFieldUpdater.newUpdater(LocalChannel.class, Future.class, "finishReadFuture");
private static final ChannelMetadata METADATA = new ChannelMetadata(false);
private static final int MAX_READER_STACK_DEPTH = 8;
private enum State { OPEN, BOUND, CONNECTED, CLOSED }
private final ChannelConfig config = new DefaultChannelConfig(this);
// To further optimize this we could write our own SPSC queue.
final Queue inboundBuffer = PlatformDependent.newSpscQueue();
private final Runnable readTask = new Runnable() {
@Override
public void run() {
// Ensure the inboundBuffer is not empty as readInbound() will always call fireChannelReadComplete()
if (!inboundBuffer.isEmpty()) {
readInbound();
}
}
};
private final Runnable shutdownHook = new Runnable() {
@Override
public void run() {
unsafe().close(unsafe().voidPromise());
}
};
private volatile State state;
private volatile LocalChannel peer;
private volatile LocalAddress localAddress;
private volatile LocalAddress remoteAddress;
private volatile ChannelPromise connectPromise;
private volatile boolean readInProgress;
private volatile boolean writeInProgress;
private volatile Future finishReadFuture;
public LocalChannel() {
super(null);
config().setAllocator(new PreferHeapByteBufAllocator(config.getAllocator()));
}
protected LocalChannel(LocalServerChannel parent, LocalChannel peer) {
super(parent);
config().setAllocator(new PreferHeapByteBufAllocator(config.getAllocator()));
this.peer = peer;
localAddress = parent.localAddress();
remoteAddress = peer.localAddress();
}
@Override
public ChannelMetadata metadata() {
return METADATA;
}
@Override
public ChannelConfig config() {
return config;
}
@Override
public LocalServerChannel parent() {
return (LocalServerChannel) super.parent();
}
@Override
public LocalAddress localAddress() {
return (LocalAddress) super.localAddress();
}
@Override
public LocalAddress remoteAddress() {
return (LocalAddress) super.remoteAddress();
}
@Override
public boolean isOpen() {
return state != State.CLOSED;
}
@Override
public boolean isActive() {
return state == State.CONNECTED;
}
@Override
protected AbstractUnsafe newUnsafe() {
return new LocalUnsafe();
}
@Override
protected boolean isCompatible(EventLoop loop) {
return loop instanceof SingleThreadEventLoop;
}
@Override
protected SocketAddress localAddress0() {
return localAddress;
}
@Override
protected SocketAddress remoteAddress0() {
return remoteAddress;
}
@Override
protected void doRegister() throws Exception {
// Check if both peer and parent are non-null because this channel was created by a LocalServerChannel.
// This is needed as a peer may not be null also if a LocalChannel was connected before and
// deregistered / registered later again.
//
// See https://github.com/netty/netty/issues/2400
if (peer != null && parent() != null) {
// Store the peer in a local variable as it may be set to null if doClose() is called.
// See https://github.com/netty/netty/issues/2144
final LocalChannel peer = this.peer;
state = State.CONNECTED;
peer.remoteAddress = parent() == null ? null : parent().localAddress();
peer.state = State.CONNECTED;
// Always call peer.eventLoop().execute() even if peer.eventLoop().inEventLoop() is true.
// This ensures that if both channels are on the same event loop, the peer's channelActive
// event is triggered *after* this channel's channelRegistered event, so that this channel's
// pipeline is fully initialized by ChannelInitializer before any channelRead events.
peer.eventLoop().execute(new Runnable() {
@Override
public void run() {
ChannelPromise promise = peer.connectPromise;
// Only trigger fireChannelActive() if the promise was not null and was not completed yet.
// connectPromise may be set to null if doClose() was called in the meantime.
if (promise != null && promise.trySuccess()) {
peer.pipeline().fireChannelActive();
}
}
});
}
((SingleThreadEventExecutor) eventLoop()).addShutdownHook(shutdownHook);
}
@Override
protected void doBind(SocketAddress localAddress) throws Exception {
this.localAddress =
LocalChannelRegistry.register(this, this.localAddress,
localAddress);
state = State.BOUND;
}
@Override
protected void doDisconnect() throws Exception {
doClose();
}
@Override
protected void doClose() throws Exception {
final LocalChannel peer = this.peer;
State oldState = state;
try {
if (oldState != State.CLOSED) {
// Update all internal state before the closeFuture is notified.
if (localAddress != null) {
if (parent() == null) {
LocalChannelRegistry.unregister(localAddress);
}
localAddress = null;
}
// State change must happen before finishPeerRead to ensure writes are released either in doWrite or
// channelRead.
state = State.CLOSED;
// Preserve order of event and force a read operation now before the close operation is processed.
if (writeInProgress && peer != null) {
finishPeerRead(peer);
}
ChannelPromise promise = connectPromise;
if (promise != null) {
// Use tryFailure() instead of setFailure() to avoid the race against cancel().
promise.tryFailure(new ClosedChannelException());
connectPromise = null;
}
}
if (peer != null) {
this.peer = null;
// Always call peer.eventLoop().execute() even if peer.eventLoop().inEventLoop() is true.
// This ensures that if both channels are on the same event loop, the peer's channelInActive
// event is triggered *after* this peer's channelInActive event
EventLoop peerEventLoop = peer.eventLoop();
final boolean peerIsActive = peer.isActive();
try {
peerEventLoop.execute(new Runnable() {
@Override
public void run() {
peer.tryClose(peerIsActive);
}
});
} catch (Throwable cause) {
logger.warn("Releasing Inbound Queues for channels {}-{} because exception occurred!",
this, peer, cause);
if (peerEventLoop.inEventLoop()) {
peer.releaseInboundBuffers();
} else {
// inboundBuffers is a SPSC so we may leak if the event loop is shutdown prematurely or
// rejects the close Runnable but give a best effort.
peer.close();
}
PlatformDependent.throwException(cause);
}
}
} finally {
// Release all buffers if the Channel was already registered in the past and if it was not closed before.
if (oldState != null && oldState != State.CLOSED) {
// We need to release all the buffers that may be put into our inbound queue since we closed the Channel
// to ensure we not leak any memory. This is fine as it basically gives the same guarantees as TCP which
// means even if the promise was notified before its not really guaranteed that the "remote peer" will
// see the buffer at all.
releaseInboundBuffers();
}
}
}
private void tryClose(boolean isActive) {
if (isActive) {
unsafe().close(unsafe().voidPromise());
} else {
releaseInboundBuffers();
}
}
@Override
protected void doDeregister() throws Exception {
// Just remove the shutdownHook as this Channel may be closed later or registered to another EventLoop
((SingleThreadEventExecutor) eventLoop()).removeShutdownHook(shutdownHook);
}
private void readInbound() {
RecvByteBufAllocator.Handle handle = unsafe().recvBufAllocHandle();
handle.reset(config());
ChannelPipeline pipeline = pipeline();
do {
Object received = inboundBuffer.poll();
if (received == null) {
break;
}
if (received instanceof ByteBuf && inboundBuffer.peek() instanceof ByteBuf) {
ByteBuf msg = (ByteBuf) received;
ByteBuf output = handle.allocate(alloc());
if (msg.readableBytes() < output.writableBytes()) {
// We have an opportunity to coalesce buffers.
output.writeBytes(msg, msg.readerIndex(), msg.readableBytes());
msg.release();
while ((received = inboundBuffer.peek()) instanceof ByteBuf &&
((ByteBuf) received).readableBytes() < output.writableBytes()) {
inboundBuffer.poll();
msg = (ByteBuf) received;
output.writeBytes(msg, msg.readerIndex(), msg.readableBytes());
msg.release();
}
handle.lastBytesRead(output.readableBytes());
received = output; // Send the coalesced buffer down the pipeline.
} else {
// It won't be profitable to coalesce buffers this time around.
handle.lastBytesRead(output.capacity());
output.release();
}
}
handle.incMessagesRead(1);
pipeline.fireChannelRead(received);
} while (handle.continueReading());
handle.readComplete();
pipeline.fireChannelReadComplete();
}
@Override
protected void doBeginRead() throws Exception {
if (readInProgress) {
return;
}
Queue inboundBuffer = this.inboundBuffer;
if (inboundBuffer.isEmpty()) {
readInProgress = true;
return;
}
final InternalThreadLocalMap threadLocals = InternalThreadLocalMap.get();
final int stackDepth = threadLocals.localChannelReaderStackDepth();
if (stackDepth < MAX_READER_STACK_DEPTH) {
threadLocals.setLocalChannelReaderStackDepth(stackDepth + 1);
try {
readInbound();
} finally {
threadLocals.setLocalChannelReaderStackDepth(stackDepth);
}
} else {
try {
eventLoop().execute(readTask);
} catch (Throwable cause) {
logger.warn("Closing Local channels {}-{} because exception occurred!", this, peer, cause);
close();
peer.close();
PlatformDependent.throwException(cause);
}
}
}
@Override
protected void doWrite(ChannelOutboundBuffer in) throws Exception {
switch (state) {
case OPEN:
case BOUND:
throw new NotYetConnectedException();
case CLOSED:
throw new ClosedChannelException();
case CONNECTED:
break;
}
final LocalChannel peer = this.peer;
writeInProgress = true;
try {
ClosedChannelException exception = null;
for (;;) {
Object msg = in.current();
if (msg == null) {
break;
}
try {
// It is possible the peer could have closed while we are writing, and in this case we should
// simulate real socket behavior and ensure the write operation is failed.
if (peer.state == State.CONNECTED) {
peer.inboundBuffer.add(ReferenceCountUtil.retain(msg));
in.remove();
} else {
if (exception == null) {
exception = new ClosedChannelException();
}
in.remove(exception);
}
} catch (Throwable cause) {
in.remove(cause);
}
}
} finally {
// The following situation may cause trouble:
// 1. Write (with promise X)
// 2. promise X is completed when in.remove() is called, and a listener on this promise calls close()
// 3. Then the close event will be executed for the peer before the write events, when the write events
// actually happened before the close event.
writeInProgress = false;
}
finishPeerRead(peer);
}
private void finishPeerRead(final LocalChannel peer) {
// If the peer is also writing, then we must schedule the event on the event loop to preserve read order.
if (peer.eventLoop() == eventLoop() && !peer.writeInProgress) {
finishPeerRead0(peer);
} else {
runFinishPeerReadTask(peer);
}
}
private void runFinishPeerReadTask(final LocalChannel peer) {
// If the peer is writing, we must wait until after reads are completed for that peer before we can read. So
// we keep track of the task, and coordinate later that our read can't happen until the peer is done.
final Runnable finishPeerReadTask = new Runnable() {
@Override
public void run() {
finishPeerRead0(peer);
}
};
try {
if (peer.writeInProgress) {
peer.finishReadFuture = peer.eventLoop().submit(finishPeerReadTask);
} else {
peer.eventLoop().execute(finishPeerReadTask);
}
} catch (Throwable cause) {
logger.warn("Closing Local channels {}-{} because exception occurred!", this, peer, cause);
close();
peer.close();
PlatformDependent.throwException(cause);
}
}
private void releaseInboundBuffers() {
assert eventLoop() == null || eventLoop().inEventLoop();
readInProgress = false;
Queue inboundBuffer = this.inboundBuffer;
Object msg;
while ((msg = inboundBuffer.poll()) != null) {
ReferenceCountUtil.release(msg);
}
}
private void finishPeerRead0(LocalChannel peer) {
Future peerFinishReadFuture = peer.finishReadFuture;
if (peerFinishReadFuture != null) {
if (!peerFinishReadFuture.isDone()) {
runFinishPeerReadTask(peer);
return;
} else {
// Lazy unset to make sure we don't prematurely unset it while scheduling a new task.
FINISH_READ_FUTURE_UPDATER.compareAndSet(peer, peerFinishReadFuture, null);
}
}
// We should only set readInProgress to false if there is any data that was read as otherwise we may miss to
// forward data later on.
if (peer.readInProgress && !peer.inboundBuffer.isEmpty()) {
peer.readInProgress = false;
peer.readInbound();
}
}
private class LocalUnsafe extends AbstractUnsafe {
@Override
public void connect(final SocketAddress remoteAddress,
SocketAddress localAddress, final ChannelPromise promise) {
if (!promise.setUncancellable() || !ensureOpen(promise)) {
return;
}
if (state == State.CONNECTED) {
Exception cause = new AlreadyConnectedException();
safeSetFailure(promise, cause);
pipeline().fireExceptionCaught(cause);
return;
}
if (connectPromise != null) {
throw new ConnectionPendingException();
}
connectPromise = promise;
if (state != State.BOUND) {
// Not bound yet and no localAddress specified - get one.
if (localAddress == null) {
localAddress = new LocalAddress(LocalChannel.this);
}
}
if (localAddress != null) {
try {
doBind(localAddress);
} catch (Throwable t) {
safeSetFailure(promise, t);
close(voidPromise());
return;
}
}
Channel boundChannel = LocalChannelRegistry.get(remoteAddress);
if (!(boundChannel instanceof LocalServerChannel)) {
Exception cause = new ConnectException("connection refused: " + remoteAddress);
safeSetFailure(promise, cause);
close(voidPromise());
return;
}
LocalServerChannel serverChannel = (LocalServerChannel) boundChannel;
peer = serverChannel.serve(LocalChannel.this);
}
}
}
