/*
* 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.channel.Channel;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.ChannelPromise;
import io.netty.channel.FileRegion;
import io.netty.channel.socket.ChannelInputShutdownEvent;
import java.io.IOException;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.WritableByteChannel;
/**
* {@link AbstractNioChannel} base class for {@link Channel}s that operate on bytes.
*/
public abstract class AbstractNioByteChannel extends AbstractNioChannel {
/**
* Create a new instance
*
* @param parent the parent {@link Channel} by which this instance was created. May be {@code null}
* @param id the id of this instance or {@code null} if one should be generated
* @param ch the underlying {@link SelectableChannel} on which it operates
*/
protected AbstractNioByteChannel(
Channel parent, Integer id, SelectableChannel ch) {
super(parent, id, ch, SelectionKey.OP_READ);
}
@Override
protected AbstractNioUnsafe newUnsafe() {
return new NioByteUnsafe();
}
private final class NioByteUnsafe extends AbstractNioUnsafe {
@Override
public void read() {
assert eventLoop().inEventLoop();
final SelectionKey key = selectionKey();
if (!config().isAutoRead()) {
// only remove readInterestOp if needed
key.interestOps(key.interestOps() & ~readInterestOp);
}
final ChannelPipeline pipeline = pipeline();
final ByteBuf byteBuf = pipeline.inboundByteBuffer();
boolean closed = false;
boolean read = false;
boolean firedChannelReadSuspended = false;
try {
expandReadBuffer(byteBuf);
loop: for (;;) {
int localReadAmount = doReadBytes(byteBuf);
if (localReadAmount > 0) {
read = true;
} else if (localReadAmount < 0) {
closed = true;
break;
}
switch (expandReadBuffer(byteBuf)) {
case 0:
// Read all - stop reading.
break loop;
case 1:
// Keep reading until everything is read.
break;
case 2:
// Let the inbound handler drain the buffer and continue reading.
if (read) {
read = false;
pipeline.fireInboundBufferUpdated();
if (!byteBuf.isWritable()) {
throw new IllegalStateException(
"an inbound handler whose buffer is full must consume at " +
"least one byte.");
}
}
}
}
} catch (Throwable t) {
if (read) {
read = false;
pipeline.fireInboundBufferUpdated();
}
if (t instanceof IOException) {
closed = true;
} else if (!closed) {
firedChannelReadSuspended = true;
pipeline.fireChannelReadSuspended();
}
pipeline().fireExceptionCaught(t);
} finally {
if (read) {
pipeline.fireInboundBufferUpdated();
}
if (closed) {
setInputShutdown();
if (isOpen()) {
if (Boolean.TRUE.equals(config().getOption(ChannelOption.ALLOW_HALF_CLOSURE))) {
key.interestOps(key.interestOps() & ~readInterestOp);
pipeline.fireUserEventTriggered(ChannelInputShutdownEvent.INSTANCE);
} else {
close(voidFuture());
}
}
} else if (!firedChannelReadSuspended) {
pipeline.fireChannelReadSuspended();
}
}
}
}
@Override
protected void doFlushByteBuffer(ByteBuf buf) throws Exception {
if (!buf.isReadable()) {
// Reset reader/writerIndex to 0 if the buffer is empty.
buf.clear();
return;
}
for (int i = config().getWriteSpinCount() - 1; i >= 0; i --) {
int localFlushedAmount = doWriteBytes(buf, i == 0);
if (localFlushedAmount > 0) {
break;
}
if (!buf.isReadable()) {
// Reset reader/writerIndex to 0 if the buffer is empty.
buf.clear();
break;
}
}
}
@Override
protected void doFlushFileRegion(final FileRegion region, final ChannelPromise promise) throws Exception {
if (javaChannel() instanceof WritableByteChannel) {
TransferTask transferTask = new TransferTask(region, (WritableByteChannel) javaChannel(), promise);
transferTask.transfer();
} else {
throw new UnsupportedOperationException("Underlying Channel is not of instance "
+ WritableByteChannel.class);
}
}
private final class TransferTask implements NioTask<SelectableChannel> {
private long writtenBytes;
private final FileRegion region;
private final WritableByteChannel wch;
private final ChannelPromise promise;
TransferTask(FileRegion region, WritableByteChannel wch, ChannelPromise promise) {
this.region = region;
this.wch = wch;
this.promise = promise;
}
void transfer() {
try {
for (;;) {
long localWrittenBytes = region.transferTo(wch, writtenBytes);
if (localWrittenBytes == 0) {
// reschedule for write once the channel is writable again
eventLoop().executeWhenWritable(
AbstractNioByteChannel.this, this);
return;
} else if (localWrittenBytes == -1) {
checkEOF(region, writtenBytes);
promise.setSuccess();
return;
} else {
writtenBytes += localWrittenBytes;
if (writtenBytes >= region.count()) {
region.release();
promise.setSuccess();
return;
}
}
}
} catch (Throwable cause) {
region.release();
promise.setFailure(cause);
}
}
@Override
public void channelReady(SelectableChannel ch, SelectionKey key) throws Exception {
transfer();
}
@Override
public void channelUnregistered(SelectableChannel ch, Throwable cause) throws Exception {
if (cause != null) {
promise.setFailure(cause);
return;
}
if (writtenBytes < region.count()) {
region.release();
if (!isOpen()) {
promise.setFailure(new ClosedChannelException());
} else {
promise.setFailure(new IllegalStateException(
"Channel was unregistered before the region could be fully written"));
}
}
}
}
/**
* 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
* @param lastSpin {@code true} if this is the last write try
* @return amount the amount of written bytes
* @throws Exception thrown if an error accour
*/
protected abstract int doWriteBytes(ByteBuf buf, boolean lastSpin) throws Exception;
}