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JDBC Driver for Google Cloud Spanner
/*
* 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 nl.topicus.jdbc.shaded.io.netty.channel.oio;
import nl.topicus.jdbc.shaded.io.netty.buffer.ByteBuf;
import nl.topicus.jdbc.shaded.io.netty.buffer.ByteBufAllocator;
import nl.topicus.jdbc.shaded.io.netty.channel.Channel;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelConfig;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelFuture;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelMetadata;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelOption;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelOutboundBuffer;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelPipeline;
import nl.topicus.jdbc.shaded.io.netty.channel.FileRegion;
import nl.topicus.jdbc.shaded.io.netty.channel.RecvByteBufAllocator;
import nl.topicus.jdbc.shaded.io.netty.channel.socket.ChannelInputShutdownEvent;
import nl.topicus.jdbc.shaded.io.netty.util.internal.StringUtil;
import java.io.IOException;
/**
* Abstract base class for OIO which reads and writes bytes from/to a Socket
*/
public abstract class AbstractOioByteChannel extends AbstractOioChannel {
private static final ChannelMetadata METADATA = new ChannelMetadata(false);
private static final String EXPECTED_TYPES =
" (expected: " + StringUtil.simpleClassName(ByteBuf.class) + ", " +
StringUtil.simpleClassName(FileRegion.class) + ')';
/**
* @see AbstractOioByteChannel#AbstractOioByteChannel(Channel)
*/
protected AbstractOioByteChannel(Channel parent) {
super(parent);
}
@Override
public ChannelMetadata metadata() {
return METADATA;
}
/**
* Determine if the input side of this channel is shutdown.
* @return {@code true} if the input side of this channel is shutdown.
*/
protected abstract boolean isInputShutdown();
/**
* Shutdown the input side of this channel.
* @return A channel future that will complete when the shutdown is complete.
*/
protected abstract ChannelFuture shutdownInput();
private void closeOnRead(ChannelPipeline pipeline) {
if (isOpen()) {
if (Boolean.TRUE.equals(config().getOption(ChannelOption.ALLOW_HALF_CLOSURE))) {
shutdownInput();
pipeline.fireUserEventTriggered(ChannelInputShutdownEvent.INSTANCE);
} else {
unsafe().close(unsafe().voidPromise());
}
}
}
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
protected void doRead() {
final ChannelConfig config = config();
if (isInputShutdown() || !readPending) {
// We have to check readPending here because the Runnable to read could have been scheduled and later
// during the same read loop readPending was set to false.
return;
}
// In OIO we should set readPending to false even if the read was not successful so we can schedule
// another read on the event loop if no reads are done.
readPending = false;
final ChannelPipeline pipeline = pipeline();
final ByteBufAllocator allocator = config.getAllocator();
final RecvByteBufAllocator.Handle allocHandle = unsafe().recvBufAllocHandle();
allocHandle.reset(config);
ByteBuf byteBuf = null;
boolean close = false;
boolean readData = false;
try {
byteBuf = allocHandle.allocate(allocator);
do {
allocHandle.lastBytesRead(doReadBytes(byteBuf));
if (allocHandle.lastBytesRead() <= 0) {
if (!byteBuf.isReadable()) { // 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;
} else {
readData = true;
}
final int available = available();
if (available <= 0) {
break;
}
// Oio collects consecutive read operations into 1 ByteBuf before propagating up the pipeline.
if (!byteBuf.isWritable()) {
final int capacity = byteBuf.capacity();
final int maxCapacity = byteBuf.maxCapacity();
if (capacity == maxCapacity) {
allocHandle.incMessagesRead(1);
readPending = false;
pipeline.fireChannelRead(byteBuf);
byteBuf = allocHandle.allocate(allocator);
} else {
final int writerIndex = byteBuf.writerIndex();
if (writerIndex + available > maxCapacity) {
byteBuf.capacity(maxCapacity);
} else {
byteBuf.ensureWritable(available);
}
}
}
} while (allocHandle.continueReading());
if (byteBuf != null) {
// It is possible we allocated a buffer because the previous one was not writable, but then didn't use
// it because allocHandle.continueReading() returned false.
if (byteBuf.isReadable()) {
readPending = false;
pipeline.fireChannelRead(byteBuf);
} else {
byteBuf.release();
}
byteBuf = null;
}
if (readData) {
allocHandle.readComplete();
pipeline.fireChannelReadComplete();
}
if (close) {
closeOnRead(pipeline);
}
} catch (Throwable t) {
handleReadException(pipeline, byteBuf, t, close, allocHandle);
} finally {
if (readPending || config.isAutoRead() || !readData && isActive()) {
// Reading 0 bytes could mean there is a SocketTimeout and no data was actually read, so we
// should execute read() again because no data may have been read.
read();
}
}
}
@Override
protected void doWrite(ChannelOutboundBuffer in) throws Exception {
for (;;) {
Object msg = in.current();
if (msg == null) {
// nothing left to write
break;
}
if (msg instanceof ByteBuf) {
ByteBuf buf = (ByteBuf) msg;
int readableBytes = buf.readableBytes();
while (readableBytes > 0) {
doWriteBytes(buf);
int newReadableBytes = buf.readableBytes();
in.progress(readableBytes - newReadableBytes);
readableBytes = newReadableBytes;
}
in.remove();
} else if (msg instanceof FileRegion) {
FileRegion region = (FileRegion) msg;
long transferred = region.transferred();
doWriteFileRegion(region);
in.progress(region.transferred() - transferred);
in.remove();
} else {
in.remove(new UnsupportedOperationException(
"unsupported message type: " + StringUtil.simpleClassName(msg)));
}
}
}
@Override
protected final Object filterOutboundMessage(Object msg) throws Exception {
if (msg instanceof ByteBuf || msg instanceof FileRegion) {
return msg;
}
throw new UnsupportedOperationException(
"unsupported message type: " + StringUtil.simpleClassName(msg) + EXPECTED_TYPES);
}
/**
* Return the number of bytes ready to read from the underlying Socket.
*/
protected abstract int available();
/**
* Read bytes from the underlying Socket.
*
* @param buf the {@link ByteBuf} into which the read bytes will be written
* @return amount the number of bytes read. This may return a negative amount if the underlying
* Socket was closed
* @throws Exception is thrown if an error occurred
*/
protected abstract int doReadBytes(ByteBuf buf) throws Exception;
/**
* Write the data which is hold by the {@link ByteBuf} to the underlying Socket.
*
* @param buf the {@link ByteBuf} which holds the data to transfer
* @throws Exception is thrown if an error occurred
*/
protected abstract void doWriteBytes(ByteBuf buf) throws Exception;
/**
* Write the data which is hold by the {@link FileRegion} to the underlying Socket.
*
* @param region the {@link FileRegion} which holds the data to transfer
* @throws Exception is thrown if an error occurred
*/
protected abstract void doWriteFileRegion(FileRegion region) throws Exception;
}