io.netty.channel.nio.AbstractNioByteChannel 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:
*
* 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 io.netty.channel.nio;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.channel.Channel;
import io.netty.channel.ChannelConfig;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelMetadata;
import io.netty.channel.ChannelOutboundBuffer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.FileRegion;
import io.netty.channel.RecvByteBufAllocator;
import io.netty.channel.internal.ChannelUtils;
import io.netty.channel.socket.ChannelInputShutdownEvent;
import io.netty.channel.socket.ChannelInputShutdownReadComplete;
import io.netty.channel.socket.SocketChannelConfig;
import io.netty.util.internal.StringUtil;
import java.io.IOException;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SelectionKey;
import static io.netty.channel.internal.ChannelUtils.WRITE_STATUS_SNDBUF_FULL;
/**
* {@link AbstractNioChannel} base class for {@link Channel}s that operate on bytes.
*/
public abstract class AbstractNioByteChannel extends AbstractNioChannel {
private static final ChannelMetadata METADATA = new ChannelMetadata(false, 16);
private static final String EXPECTED_TYPES =
" (expected: " + StringUtil.simpleClassName(ByteBuf.class) + ", " +
StringUtil.simpleClassName(FileRegion.class) + ')';
private final Runnable flushTask = new Runnable() {
@Override
public void run() {
// Calling flush0 directly to ensure we not try to flush messages that were added via write(...) in the
// meantime.
((AbstractNioUnsafe) unsafe()).flush0();
}
};
private boolean inputClosedSeenErrorOnRead;
/**
* 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
*/
protected AbstractNioByteChannel(Channel parent, SelectableChannel ch) {
super(parent, ch, SelectionKey.OP_READ);
}
/**
* Shutdown the input side of the channel.
*/
protected abstract ChannelFuture shutdownInput();
protected boolean isInputShutdown0() {
return false;
}
@Override
protected AbstractNioUnsafe newUnsafe() {
return new NioByteUnsafe();
}
@Override
public ChannelMetadata metadata() {
return METADATA;
}
final boolean shouldBreakReadReady(ChannelConfig config) {
return isInputShutdown0() && (inputClosedSeenErrorOnRead || !isAllowHalfClosure(config));
}
private static boolean isAllowHalfClosure(ChannelConfig config) {
return config instanceof SocketChannelConfig &&
((SocketChannelConfig) config).isAllowHalfClosure();
}
protected class NioByteUnsafe extends AbstractNioUnsafe {
private void closeOnRead(ChannelPipeline pipeline) {
if (!isInputShutdown0()) {
if (isAllowHalfClosure(config())) {
shutdownInput();
pipeline.fireUserEventTriggered(ChannelInputShutdownEvent.INSTANCE);
} else {
close(voidPromise());
}
} else {
inputClosedSeenErrorOnRead = true;
pipeline.fireUserEventTriggered(ChannelInputShutdownReadComplete.INSTANCE);
}
}
private void handleReadException(ChannelPipeline pipeline, ByteBuf byteBuf, Throwable cause, boolean close,
RecvByteBufAllocator.Handle allocHandle) {
if (byteBuf != null) {
if (byteBuf.isReadable()) {
readPending = false;
pipeline.fireChannelRead(byteBuf);
} else {
byteBuf.release();
}
}
allocHandle.readComplete();
pipeline.fireChannelReadComplete();
pipeline.fireExceptionCaught(cause);
if (close || cause instanceof IOException) {
closeOnRead(pipeline);
}
}
@Override
public final void read() {
final ChannelConfig config = config();
if (shouldBreakReadReady(config)) {
clearReadPending();
return;
}
final ChannelPipeline pipeline = pipeline();
final ByteBufAllocator allocator = config.getAllocator();
final RecvByteBufAllocator.Handle allocHandle = recvBufAllocHandle();
allocHandle.reset(config);
ByteBuf byteBuf = null;
boolean close = false;
try {
do {
byteBuf = allocHandle.allocate(allocator);
allocHandle.lastBytesRead(doReadBytes(byteBuf));
if (allocHandle.lastBytesRead() <= 0) {
// nothing was read. release the buffer.
byteBuf.release();
byteBuf = null;
close = allocHandle.lastBytesRead() < 0;
if (close) {
// There is nothing left to read as we received an EOF.
readPending = false;
}
break;
}
allocHandle.incMessagesRead(1);
readPending = false;
pipeline.fireChannelRead(byteBuf);
byteBuf = null;
} while (allocHandle.continueReading());
allocHandle.readComplete();
pipeline.fireChannelReadComplete();
if (close) {
closeOnRead(pipeline);
}
} catch (Throwable t) {
handleReadException(pipeline, byteBuf, t, close, allocHandle);
} finally {
// Check if there is a readPending which was not processed yet.
// This could be for two reasons:
// * The user called Channel.read() or ChannelHandlerContext.read() in channelRead(...) method
// * The user called Channel.read() or ChannelHandlerContext.read() in channelReadComplete(...) method
//
// See https://github.com/netty/netty/issues/2254
if (!readPending && !config.isAutoRead()) {
removeReadOp();
}
}
}
}
/**
* Write objects to the OS.
* @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 ByteBuf} (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 exception occurs during write.
*/
protected final int doWrite0(ChannelOutboundBuffer in) throws Exception {
Object msg = in.current();
if (msg == null) {
// Directly return here so incompleteWrite(...) is not called.
return 0;
}
return doWriteInternal(in, in.current());
}
private int doWriteInternal(ChannelOutboundBuffer in, Object msg) throws Exception {
if (msg instanceof ByteBuf) {
ByteBuf buf = (ByteBuf) msg;
if (!buf.isReadable()) {
in.remove();
return 0;
}
final int localFlushedAmount = doWriteBytes(buf);
if (localFlushedAmount > 0) {
in.progress(localFlushedAmount);
if (!buf.isReadable()) {
in.remove();
}
return 1;
}
} else if (msg instanceof FileRegion) {
FileRegion region = (FileRegion) msg;
if (region.transferred() >= region.count()) {
in.remove();
return 0;
}
long localFlushedAmount = doWriteFileRegion(region);
if (localFlushedAmount > 0) {
in.progress(localFlushedAmount);
if (region.transferred() >= region.count()) {
in.remove();
}
return 1;
}
} else {
// Should not reach here.
throw new Error();
}
return WRITE_STATUS_SNDBUF_FULL;
}
@Override
protected void doWrite(ChannelOutboundBuffer in) throws Exception {
int writeSpinCount = config().getWriteSpinCount();
do {
Object msg = in.current();
if (msg == null) {
// Wrote all messages.
clearOpWrite();
// Directly return here so incompleteWrite(...) is not called.
return;
}
writeSpinCount -= doWriteInternal(in, msg);
} while (writeSpinCount > 0);
incompleteWrite(writeSpinCount < 0);
}
@Override
protected final Object filterOutboundMessage(Object msg) {
if (msg instanceof ByteBuf) {
ByteBuf buf = (ByteBuf) msg;
if (buf.isDirect()) {
return msg;
}
return newDirectBuffer(buf);
}
if (msg instanceof FileRegion) {
return msg;
}
throw new UnsupportedOperationException(
"unsupported message type: " + StringUtil.simpleClassName(msg) + EXPECTED_TYPES);
}
protected final void incompleteWrite(boolean setOpWrite) {
// Did not write completely.
if (setOpWrite) {
setOpWrite();
} else {
// It is possible that we have set the write OP, woken up by NIO because the socket is writable, and then
// use our write quantum. In this case we no longer want to set the write OP 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 write OP if necessary.
clearOpWrite();
// Schedule flush again later so other tasks can be picked up in the meantime
eventLoop().execute(flushTask);
}
}
/**
* Write a {@link FileRegion}
*
* @param region the {@link FileRegion} from which the bytes should be written
* @return amount the amount of written bytes
*/
protected abstract long doWriteFileRegion(FileRegion region) throws Exception;
/**
* Read bytes into the given {@link ByteBuf} and return the amount.
*/
protected abstract int doReadBytes(ByteBuf buf) throws Exception;
/**
* Write bytes form the given {@link ByteBuf} to the underlying {@link java.nio.channels.Channel}.
* @param buf the {@link ByteBuf} from which the bytes should be written
* @return amount the amount of written bytes
*/
protected abstract int doWriteBytes(ByteBuf buf) throws Exception;
protected final void setOpWrite() {
final SelectionKey key = selectionKey();
// 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 (!key.isValid()) {
return;
}
final int interestOps = key.interestOps();
if ((interestOps & SelectionKey.OP_WRITE) == 0) {
key.interestOps(interestOps | SelectionKey.OP_WRITE);
}
}
protected final void clearOpWrite() {
final SelectionKey key = selectionKey();
// 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 (!key.isValid()) {
return;
}
final int interestOps = key.interestOps();
if ((interestOps & SelectionKey.OP_WRITE) != 0) {
key.interestOps(interestOps & ~SelectionKey.OP_WRITE);
}
}
}