io.netty5.channel.epoll.AbstractEpollStreamChannel Maven / Gradle / Ivy
/*
* Copyright 2015 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.netty5.channel.epoll;
import io.netty5.buffer.api.Buffer;
import io.netty5.buffer.api.BufferAllocator;
import io.netty5.buffer.api.Resource;
import io.netty5.channel.Channel;
import io.netty5.channel.ChannelConfig;
import io.netty5.channel.ChannelMetadata;
import io.netty5.channel.ChannelOutboundBuffer;
import io.netty5.channel.ChannelPipeline;
import io.netty5.channel.DefaultFileRegion;
import io.netty5.channel.EventLoop;
import io.netty5.channel.FileRegion;
import io.netty5.channel.RecvBufferAllocator.Handle;
import io.netty5.channel.internal.ChannelUtils;
import io.netty5.channel.socket.DuplexChannel;
import io.netty5.channel.unix.IovArray;
import io.netty5.channel.unix.SocketWritableByteChannel;
import io.netty5.channel.unix.UnixChannelUtil;
import io.netty5.util.concurrent.Future;
import io.netty5.util.concurrent.Promise;
import io.netty5.util.internal.StringUtil;
import io.netty5.util.internal.UnstableApi;
import io.netty5.util.internal.logging.InternalLogger;
import io.netty5.util.internal.logging.InternalLoggerFactory;
import java.io.IOException;
import java.net.SocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.WritableByteChannel;
import java.util.concurrent.Executor;
import static io.netty5.channel.internal.ChannelUtils.MAX_BYTES_PER_GATHERING_WRITE_ATTEMPTED_LOW_THRESHOLD;
import static io.netty5.channel.internal.ChannelUtils.WRITE_STATUS_SNDBUF_FULL;
public abstract class AbstractEpollStreamChannel extends AbstractEpollChannel implements DuplexChannel {
private static final ChannelMetadata METADATA = new ChannelMetadata(false, 16);
private static final String EXPECTED_TYPES =
" (expected: " + StringUtil.simpleClassName(Buffer.class) + ", " +
StringUtil.simpleClassName(DefaultFileRegion.class) + ')';
private static final InternalLogger logger = InternalLoggerFactory.getInstance(AbstractEpollStreamChannel.class);
private final Runnable flushTask = () -> {
// Calling flush0 directly to ensure we not try to flush messages that were added via write(...) in the
// meantime.
((AbstractEpollUnsafe) unsafe()).flush0();
};
private WritableByteChannel byteChannel;
protected AbstractEpollStreamChannel(Channel parent, EventLoop eventLoop, int fd) {
this(parent, eventLoop, new LinuxSocket(fd));
}
protected AbstractEpollStreamChannel(EventLoop eventLoop, int fd) {
this(eventLoop, new LinuxSocket(fd));
}
AbstractEpollStreamChannel(EventLoop eventLoop, LinuxSocket fd) {
this(eventLoop, fd, isSoErrorZero(fd));
}
AbstractEpollStreamChannel(Channel parent, EventLoop eventLoop, LinuxSocket fd) {
super(parent, eventLoop, fd, true);
// Add EPOLLRDHUP so we are notified once the remote peer close the connection.
flags |= Native.EPOLLRDHUP;
}
AbstractEpollStreamChannel(Channel parent, EventLoop eventLoop, LinuxSocket fd, SocketAddress remote) {
super(parent, eventLoop, fd, remote);
// Add EPOLLRDHUP so we are notified once the remote peer close the connection.
flags |= Native.EPOLLRDHUP;
}
protected AbstractEpollStreamChannel(EventLoop eventLoop, LinuxSocket fd, boolean active) {
super(null, eventLoop, fd, active);
// Add EPOLLRDHUP so we are notified once the remote peer close the connection.
flags |= Native.EPOLLRDHUP;
}
@Override
protected AbstractEpollUnsafe newUnsafe() {
return new EpollStreamUnsafe();
}
@Override
public abstract EpollDuplexChannelConfig config();
@Override
public ChannelMetadata metadata() {
return METADATA;
}
/**
* Write bytes form the given {@link Buffer} to the underlying {@link java.nio.channels.Channel}.
* @param in the collection which contains objects to write.
* @param buf the {@link Buffer} from which the bytes should be written
* @return The value that should be decremented from the write-quantum which starts at
* {@link ChannelConfig#getWriteSpinCount()}. The typical use cases are as follows:
*
* - 0 - if no write was attempted. This is appropriate if an empty {@link Buffer} (or other empty content)
* is encountered
* - 1 - if a single call to write data was made to the OS
* - {@link ChannelUtils#WRITE_STATUS_SNDBUF_FULL} - if an attempt to write data was made to the OS, but
* no data was accepted
*
*/
private int writeBytes(ChannelOutboundBuffer in, Buffer buf) throws Exception {
int readableBytes = buf.readableBytes();
if (readableBytes == 0) {
in.remove();
return 0;
}
int readableComponents = buf.countReadableComponents();
if (readableComponents == 1) {
return doWriteBytes(in, buf);
} else {
ByteBuffer[] nioBuffers = new ByteBuffer[readableComponents];
buf.forEachReadable(0, (index, component) -> {
nioBuffers[index] = component.readableBuffer();
return true;
});
return writeBytesMultiple(in, nioBuffers, nioBuffers.length, readableBytes,
config().getMaxBytesPerGatheringWrite());
}
}
private void adjustMaxBytesPerGatheringWrite(long attempted, long written, long oldMaxBytesPerGatheringWrite) {
// By default we track the SO_SNDBUF when ever it is explicitly set. However some OSes may dynamically change
// SO_SNDBUF (and other characteristics that determine how much data can be written at once) so we should try
// make a best effort to adjust as OS behavior changes.
if (attempted == written) {
if (attempted << 1 > oldMaxBytesPerGatheringWrite) {
config().setMaxBytesPerGatheringWrite(attempted << 1);
}
} else if (attempted > MAX_BYTES_PER_GATHERING_WRITE_ATTEMPTED_LOW_THRESHOLD && written < attempted >>> 1) {
config().setMaxBytesPerGatheringWrite(attempted >>> 1);
}
}
/**
* Write multiple bytes via {@link IovArray}.
* @param in the collection which contains objects to write.
* @param array The array which contains the content to write.
* @return The value that should be decremented from the write quantum which starts at
* {@link ChannelConfig#getWriteSpinCount()}. The typical use cases are as follows:
*
* - 0 - if no write was attempted. This is appropriate if an empty {@link Buffer} (or other empty content)
* is encountered
* - 1 - if a single call to write data was made to the OS
* - {@link ChannelUtils#WRITE_STATUS_SNDBUF_FULL} - if an attempt to write data was made to the OS, but
* no data was accepted
*
* @throws IOException If an I/O exception occurs during write.
*/
private int writeBytesMultiple(ChannelOutboundBuffer in, IovArray array) throws IOException {
final long expectedWrittenBytes = array.size();
assert expectedWrittenBytes != 0;
final int cnt = array.count();
assert cnt != 0;
final long localWrittenBytes = socket.writevAddresses(array.memoryAddress(0), cnt);
if (localWrittenBytes > 0) {
adjustMaxBytesPerGatheringWrite(expectedWrittenBytes, localWrittenBytes, array.maxBytes());
in.removeBytes(localWrittenBytes);
return 1;
}
return WRITE_STATUS_SNDBUF_FULL;
}
/**
* Write multiple bytes via {@link ByteBuffer} array.
* @param in the collection which contains objects to write.
* @param nioBuffers The buffers to write.
* @param nioBufferCnt The number of buffers to write.
* @param expectedWrittenBytes The number of bytes we expect to write.
* @param maxBytesPerGatheringWrite The maximum number of bytes we should attempt to write.
* @return The value that should be decremented from the write quantum which starts at
* {@link ChannelConfig#getWriteSpinCount()}. The typical use cases are as follows:
*
* - 0 - if no write was attempted. This is appropriate if an empty {@link Buffer} (or other empty content)
* is encountered
* - 1 - if a single call to write data was made to the OS
* - {@link ChannelUtils#WRITE_STATUS_SNDBUF_FULL} - if an attempt to write data was made to the OS, but
* no data was accepted
*
* @throws IOException If an I/O exception occurs during write.
*/
private int writeBytesMultiple(
ChannelOutboundBuffer in, ByteBuffer[] nioBuffers, int nioBufferCnt, long expectedWrittenBytes,
long maxBytesPerGatheringWrite) throws IOException {
assert expectedWrittenBytes != 0;
if (expectedWrittenBytes > maxBytesPerGatheringWrite) {
expectedWrittenBytes = maxBytesPerGatheringWrite;
}
final long localWrittenBytes = socket.writev(nioBuffers, 0, nioBufferCnt, expectedWrittenBytes);
if (localWrittenBytes > 0) {
adjustMaxBytesPerGatheringWrite(expectedWrittenBytes, localWrittenBytes, maxBytesPerGatheringWrite);
in.removeBytes(localWrittenBytes);
return 1;
}
return WRITE_STATUS_SNDBUF_FULL;
}
/**
* Write a {@link DefaultFileRegion}
* @param in the collection which contains objects to write.
* @param region the {@link DefaultFileRegion} from which the bytes should be written
* @return The value that should be decremented from the write quantum which starts at
* {@link ChannelConfig#getWriteSpinCount()}. The typical use cases are as follows:
*
* - 0 - if no write was attempted. This is appropriate if an empty {@link Buffer} (or other empty content)
* is encountered
* - 1 - if a single call to write data was made to the OS
* - {@link ChannelUtils#WRITE_STATUS_SNDBUF_FULL} - if an attempt to write data was made to the OS, but
* no data was accepted
*
*/
private int writeDefaultFileRegion(ChannelOutboundBuffer in, DefaultFileRegion region) throws Exception {
final long offset = region.transferred();
final long regionCount = region.count();
if (offset >= regionCount) {
in.remove();
return 0;
}
final long flushedAmount = socket.sendFile(region, region.position(), offset, regionCount - offset);
if (flushedAmount > 0) {
in.progress(flushedAmount);
if (region.transferred() >= regionCount) {
in.remove();
}
return 1;
}
if (flushedAmount == 0) {
validateFileRegion(region, offset);
}
return WRITE_STATUS_SNDBUF_FULL;
}
/**
* Write a {@link FileRegion}
* @param in the collection which contains objects to write.
* @param region the {@link FileRegion} from which the bytes should be written
* @return The value that should be decremented from the write quantum which starts at
* {@link ChannelConfig#getWriteSpinCount()}. The typical use cases are as follows:
*
* - 0 - if no write was attempted. This is appropriate if an empty {@link Buffer} (or other empty content)
* is encountered
* - 1 - if a single call to write data was made to the OS
* - {@link ChannelUtils#WRITE_STATUS_SNDBUF_FULL} - if an attempt to write data was made to the OS, but
* no data was accepted
*
*/
private int writeFileRegion(ChannelOutboundBuffer in, FileRegion region) throws Exception {
if (region.transferred() >= region.count()) {
in.remove();
return 0;
}
if (byteChannel == null) {
byteChannel = new EpollSocketWritableByteChannel();
}
final long flushedAmount = region.transferTo(byteChannel, region.transferred());
if (flushedAmount > 0) {
in.progress(flushedAmount);
if (region.transferred() >= region.count()) {
in.remove();
}
return 1;
}
return WRITE_STATUS_SNDBUF_FULL;
}
@Override
protected void doWrite(ChannelOutboundBuffer in) throws Exception {
int writeSpinCount = config().getWriteSpinCount();
do {
final int msgCount = in.size();
// Do gathering write if the outbound buffer entries start with more than one Buffer.
if (msgCount > 1 && in.current() instanceof Buffer) {
writeSpinCount -= doWriteMultiple(in);
} else if (msgCount == 0) {
// Wrote all messages.
clearFlag(Native.EPOLLOUT);
// Return here so we not set the EPOLLOUT flag.
return;
} else { // msgCount == 1
writeSpinCount -= doWriteSingle(in);
}
// We do not break the loop here even if the outbound buffer was flushed completely,
// because a user might have triggered another write and flush when we notify his or her
// listeners.
} while (writeSpinCount > 0);
if (writeSpinCount == 0) {
// It is possible that we have set EPOLLOUT, woken up by EPOLL because the socket is writable, and then use
// our write quantum. In this case we no longer want to set the EPOLLOUT flag because the socket is still
// writable (as far as we know). We will find out next time we attempt to write if the socket is writable
// and set the EPOLLOUT if necessary.
clearFlag(Native.EPOLLOUT);
// We used our writeSpin quantum, and should try to write again later.
executor().execute(flushTask);
} else {
// Underlying descriptor can not accept all data currently, so set the EPOLLOUT flag to be woken up
// when it can accept more data.
setFlag(Native.EPOLLOUT);
}
}
/**
* Attempt to write a single object.
* @param in the collection which contains objects to write.
* @return The value that should be decremented from the write quantum which starts at
* {@link ChannelConfig#getWriteSpinCount()}. The typical use cases are as follows:
*
* - 0 - if no write was attempted. This is appropriate if an empty {@link Buffer} (or other empty content)
* is encountered
* - 1 - if a single call to write data was made to the OS
* - {@link ChannelUtils#WRITE_STATUS_SNDBUF_FULL} - if an attempt to write data was made to the OS, but
* no data was accepted
*
* @throws Exception If an I/O error occurs.
*/
protected int doWriteSingle(ChannelOutboundBuffer in) throws Exception {
// The outbound buffer contains only one message or it contains a file region.
Object msg = in.current();
if (msg instanceof Buffer) {
return writeBytes(in, (Buffer) msg);
} else if (msg instanceof DefaultFileRegion) {
return writeDefaultFileRegion(in, (DefaultFileRegion) msg);
} else if (msg instanceof FileRegion) {
return writeFileRegion(in, (FileRegion) msg);
} else {
// Should never reach here.
throw new Error();
}
}
/**
* Attempt to write multiple {@link Buffer} objects.
* @param in the collection which contains objects to write.
* @return The value that should be decremented from the write quantum which starts at
* {@link ChannelConfig#getWriteSpinCount()}. The typical use cases are as follows:
*
* - 0 - if no write was attempted. This is appropriate if an empty {@link Buffer} (or other empty content)
* is encountered
* - 1 - if a single call to write data was made to the OS
* - {@link ChannelUtils#WRITE_STATUS_SNDBUF_FULL} - if an attempt to write data was made to the OS, but
* no data was accepted
*
* @throws Exception If an I/O error occurs.
*/
private int doWriteMultiple(ChannelOutboundBuffer in) throws Exception {
final long maxBytesPerGatheringWrite = config().getMaxBytesPerGatheringWrite();
IovArray array = registration().cleanIovArray();
array.maxBytes(maxBytesPerGatheringWrite);
in.forEachFlushedMessage(array);
if (array.count() >= 1) {
return writeBytesMultiple(in, array);
}
// cnt == 0, which means the outbound buffer contained empty buffers only.
in.removeBytes(0);
return 0;
}
@Override
protected Object filterOutboundMessage(Object msg) {
if (msg instanceof Buffer) {
Buffer buf = (Buffer) msg;
return UnixChannelUtil.isBufferCopyNeededForWrite(buf)? newDirectBuffer(buf) : buf;
}
if (msg instanceof FileRegion) {
return msg;
}
throw new UnsupportedOperationException(
"unsupported message type: " + StringUtil.simpleClassName(msg) + EXPECTED_TYPES);
}
@UnstableApi
@Override
protected final void doShutdownOutput() throws Exception {
socket.shutdown(false, true);
}
private void shutdownInput0(Promise promise) {
try {
socket.shutdown(true, false);
promise.setSuccess(null);
} catch (Throwable cause) {
promise.setFailure(cause);
}
}
@Override
public boolean isOutputShutdown() {
return socket.isOutputShutdown();
}
@Override
public boolean isInputShutdown() {
return socket.isInputShutdown();
}
@Override
public boolean isShutdown() {
return socket.isShutdown();
}
@Override
public Future shutdownOutput() {
return shutdownOutput(newPromise());
}
@Override
public Future shutdownOutput(final Promise promise) {
EventLoop loop = executor();
if (loop.inEventLoop()) {
((AbstractUnsafe) unsafe()).shutdownOutput(promise);
} else {
loop.execute(() -> ((AbstractUnsafe) unsafe()).shutdownOutput(promise));
}
return promise.asFuture();
}
@Override
public Future shutdownInput() {
return shutdownInput(newPromise());
}
@Override
public Future shutdownInput(final Promise promise) {
Executor closeExecutor = ((EpollStreamUnsafe) unsafe()).prepareToClose();
if (closeExecutor != null) {
closeExecutor.execute(() -> shutdownInput0(promise));
} else {
EventLoop loop = executor();
if (loop.inEventLoop()) {
shutdownInput0(promise);
} else {
loop.execute(() -> shutdownInput0(promise));
}
}
return promise.asFuture();
}
@Override
public Future shutdown() {
return shutdown(newPromise());
}
@Override
public Future shutdown(Promise promise) {
Future shutdownOutputFuture = shutdownOutput();
if (shutdownOutputFuture.isDone()) {
shutdownOutputDone(promise, shutdownOutputFuture);
} else {
shutdownOutputFuture.addListener(promise, this::shutdownOutputDone);
}
return promise.asFuture();
}
private void shutdownOutputDone(Promise promise, Future shutdownOutputFuture) {
Future shutdownInputFuture = shutdownInput();
if (shutdownInputFuture.isDone()) {
shutdownDone(shutdownOutputFuture, shutdownInputFuture, promise);
} else {
shutdownInputFuture.addListener(shutdownInputFuture1 ->
shutdownDone(shutdownOutputFuture, shutdownInputFuture1, promise));
}
}
private static void shutdownDone(Future shutdownOutputFuture,
Future shutdownInputFuture,
Promise promise) {
Throwable shutdownOutputCause = shutdownOutputFuture.cause();
Throwable shutdownInputCause = shutdownInputFuture.cause();
if (shutdownOutputCause != null) {
if (shutdownInputCause != null) {
logger.debug("Exception suppressed because a previous exception occurred.",
shutdownInputCause);
}
promise.setFailure(shutdownOutputCause);
} else if (shutdownInputCause != null) {
promise.setFailure(shutdownInputCause);
} else {
promise.setSuccess(null);
}
}
class EpollStreamUnsafe extends AbstractEpollUnsafe {
// Overridden here just to be able to access this method from AbstractEpollStreamChannel
@Override
protected Executor prepareToClose() {
return super.prepareToClose();
}
private void handleReadException(ChannelPipeline pipeline, Buffer buffer, Throwable cause, boolean close,
EpollRecvBufferAllocatorHandle allocHandle) {
if (buffer.readableBytes() > 0) {
readPending = false;
pipeline.fireChannelRead(buffer);
} else {
buffer.close();
}
allocHandle.readComplete();
pipeline.fireChannelReadComplete();
pipeline.fireExceptionCaught(cause);
// If oom will close the read event, release connection.
// See https://github.com/netty/netty/issues/10434
if (close || cause instanceof OutOfMemoryError || cause instanceof IOException) {
shutdownInput(false);
} else {
readIfIsAutoRead();
}
}
@Override
EpollRecvBufferAllocatorHandle newEpollHandle(Handle handle) {
return new EpollRecvBufferAllocatorStreamingHandle(handle);
}
@Override
void epollInReady() {
final ChannelConfig config = config();
if (shouldBreakEpollInReady(config)) {
clearEpollIn0();
return;
}
final EpollRecvBufferAllocatorHandle recvAlloc = recvBufAllocHandle();
final ChannelPipeline pipeline = pipeline();
final BufferAllocator bufferAllocator = config.getBufferAllocator();
recvAlloc.reset(config);
epollInBefore();
Buffer buffer = null;
boolean close = false;
try {
do {
// we use a direct buffer here as the native implementations only be able
// to handle direct buffers.
buffer = recvAlloc.allocate(bufferAllocator);
doReadBytes(buffer);
if (recvAlloc.lastBytesRead() <= 0) {
// nothing was read, release the buffer.
Resource.dispose(buffer);
buffer = null;
close = recvAlloc.lastBytesRead() < 0;
if (close) {
// There is nothing left to read as we received an EOF.
readPending = false;
}
break;
}
recvAlloc.incMessagesRead(1);
readPending = false;
pipeline.fireChannelRead(buffer);
buffer = null;
if (shouldBreakEpollInReady(config)) {
// We need to do this for two reasons:
//
// - If the input was shutdown in between (which may be the case when the user did it in the
// fireChannelRead(...) method we should not try to read again to not produce any
// miss-leading exceptions.
//
// - If the user closes the channel we need to ensure we not try to read from it again as
// the filedescriptor may be re-used already by the OS if the system is handling a lot of
// concurrent connections and so needs a lot of filedescriptors. If not do this we risk
// reading data from a filedescriptor that belongs to another socket then the socket that
// was "wrapped" by this Channel implementation.
break;
}
} while (recvAlloc.continueReading());
recvAlloc.readComplete();
pipeline.fireChannelReadComplete();
if (close) {
shutdownInput(false);
} else {
readIfIsAutoRead();
}
} catch (Throwable t) {
handleReadException(pipeline, buffer, t, close, recvAlloc);
} finally {
epollInFinally(config);
}
}
}
private final class EpollSocketWritableByteChannel extends SocketWritableByteChannel {
EpollSocketWritableByteChannel() {
super(socket);
}
@Override
protected BufferAllocator alloc() {
return bufferAllocator();
}
}
}
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