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JDBC Type 4 driver for MySQL
/*
* Copyright (c) 2020, Oracle and/or its affiliates.
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License, version 2.0, as published by the
* Free Software Foundation.
*
* This program is also distributed with certain software (including but not
* limited to OpenSSL) that is licensed under separate terms, as designated in a
* particular file or component or in included license documentation. The
* authors of MySQL hereby grant you an additional permission to link the
* program and your derivative works with the separately licensed software that
* they have included with MySQL.
*
* Without limiting anything contained in the foregoing, this file, which is
* part of MySQL Connector/J, is also subject to the Universal FOSS Exception,
* version 1.0, a copy of which can be found at
* http://oss.oracle.com/licenses/universal-foss-exception.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
* for more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package com.mysql.cj.protocol.x;
import static com.mysql.cj.protocol.x.XMessageHeader.HEADER_LENGTH;
import java.io.ByteArrayOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.Arrays;
import com.google.protobuf.ByteString;
import com.mysql.cj.x.protobuf.Mysqlx.ClientMessages;
import com.mysql.cj.x.protobuf.MysqlxConnection.Compression;
/**
* An {@link OutputStream} wrapper that analyzes X Protocol frames and routes them directly to the original underlying {@link OutputStream} or passes them
* through to a compressor-able {@link OutputStream} to compresses the frame, rebuilds it and then sends a newly compressed X Protocol frame, depending on
* defined data size threshold.
*/
public class CompressionSplittedOutputStream extends FilterOutputStream {
private CompressorStreamsFactory compressorIoStreamsFactory;
private byte[] frameHeader = new byte[HEADER_LENGTH];
private int frameHeaderBuffered = 0;
private int frameHeaderDumped = 0;
private int framePayloadLength = 0;
private int framePayloadDumped = 0;
private XMessageHeader xMessageHeader = null;
private boolean compressionEnabled = false;
private ByteArrayOutputStream bufferOut = null;
private OutputStream compressorOut = null;
private byte[] singleByte = new byte[1];
private boolean closed = false;
public CompressionSplittedOutputStream(OutputStream out, CompressorStreamsFactory ioStreamsFactory) {
super(out);
this.compressorIoStreamsFactory = ioStreamsFactory;
}
/**
* Closes this stream.
*
* @see FilterOutputStream#close()
*/
@Override
public void close() throws IOException {
if (!this.closed) {
super.close();
this.out = null;
this.bufferOut = null;
if (this.compressorOut != null) {
this.compressorOut.close();
}
this.compressorOut = null;
this.closed = true;
}
}
/**
* Forwards the write to {@link #write(byte[], int, int)};
*
* @see FilterOutputStream#write(int)
*/
@Override
public void write(int b) throws IOException {
ensureOpen();
this.singleByte[0] = (byte) b;
write(this.singleByte, 0, 1);
}
/**
* Forwards the write to {@link #write(byte[], int, int)};
*
* @see FilterOutputStream#write(byte[])
*/
@Override
public void write(byte[] b) throws IOException {
ensureOpen();
write(b, 0, b.length);
}
/**
* Analyzes the given bytes as an X Protocol frame and, depending on its size, writes it as-is in the underlying {@link OutputStream} or rebuilds it as a
* compressed X Protocol packet.
*
* @see java.io.FilterOutputStream#write(int)
*/
@Override
public void write(byte[] b, int off, int len) throws IOException {
ensureOpen();
if ((off | len | (b.length - (len + off)) | (off + len)) < 0) { // Borrowed from FilterOutputStream.
throw new IndexOutOfBoundsException();
}
int bytesProcessed = peekFrameHeader(b, off, len);
if (isFrameHeaderBuffered() && !isFrameHeaderWriteComplete()) {
this.xMessageHeader = new XMessageHeader(this.frameHeader);
this.framePayloadLength = this.xMessageHeader.getMessageSize();
this.framePayloadDumped = 0;
this.compressionEnabled = this.framePayloadLength >= 250; // Compression threshold. May be user configurable in the future.
if (this.compressionEnabled) {
this.bufferOut = new ByteArrayOutputStream();
this.compressorOut = this.compressorIoStreamsFactory.getOutputStreamInstance(this.bufferOut);
this.compressorOut.write(this.frameHeader, 0, HEADER_LENGTH);
} else {
this.out.write(this.frameHeader, 0, HEADER_LENGTH);
}
this.frameHeaderDumped = HEADER_LENGTH;
}
int bytesToDump = len - bytesProcessed;
if (bytesToDump > 0) {
if (this.compressionEnabled) {
this.compressorOut.write(b, off + bytesProcessed, bytesToDump);
} else {
this.out.write(b, off + bytesProcessed, bytesToDump);
}
}
this.framePayloadDumped += bytesToDump;
finalizeWrite();
}
/**
* Captures the first bytes of each X Protocol frame into a byte buffer.
*
* @param b
* the data.
* @param off
* the start offset in the data.
* @param len
* the number of bytes to write.
* @return
* the number of bytes actually buffered.
*/
private int peekFrameHeader(byte[] b, int off, int len) {
if (isPayloadWriteReady()) {
return 0;
}
int toCollect = 0;
if (this.frameHeaderBuffered < HEADER_LENGTH) {
toCollect = Math.min(len, HEADER_LENGTH - this.frameHeaderBuffered);
System.arraycopy(b, off, this.frameHeader, this.frameHeaderBuffered, toCollect);
this.frameHeaderBuffered += toCollect;
}
return toCollect;
}
/**
* Checks if there is a complete frame header already buffered.
*
* @return
* true if the frame header buffer is full, false otherwise.
*/
private boolean isFrameHeaderBuffered() {
return this.frameHeaderBuffered == HEADER_LENGTH;
}
/**
* Checks if the entire frame X Protocol frame header has been fully written.
*
* @return
* true if the frame header was written, false otherwise.
*/
private boolean isFrameHeaderWriteComplete() {
return this.frameHeaderDumped == HEADER_LENGTH;
}
/**
* Checks if the X Protocol frame payload is ready to be written on the underlying {@link OutputStream}.
*
* @return
* true the payload can be written, false otherwise.
*/
private boolean isPayloadWriteReady() {
return isFrameHeaderWriteComplete() && this.framePayloadDumped < this.framePayloadLength;
}
/**
* Checks if current X Protocol frame has been fully written.
*
* @return
* true if the frame currently in progress was fully written, false otherwise.
*/
private boolean isWriteComplete() {
return isFrameHeaderWriteComplete() && this.framePayloadDumped >= this.framePayloadLength;
}
/**
* Finalizes the writing of the compressed {@link OutputStream}, if one is currently in use, by flushing it into a temporary buffer and reassembling the
* original X Protocol frame into a compressed one. Finally, writes the entire compressed frame into the underlying {@link OutputStream}.
*
* @throws IOException
* if any of the underlying I/O operations fail.
*/
private void finalizeWrite() throws IOException {
if (isWriteComplete()) {
if (this.compressionEnabled) {
this.compressorOut.close();
this.compressorOut = null;
byte[] compressedData = this.bufferOut.toByteArray();
Compression compressedMessage = Compression.newBuilder().setUncompressedSize(XMessageHeader.HEADER_LENGTH + this.framePayloadLength)
.setClientMessages(ClientMessages.Type.forNumber(this.xMessageHeader.getMessageType())).setPayload(ByteString.copyFrom(compressedData))
.build();
ByteBuffer messageHeader = ByteBuffer.allocate(XMessageHeader.HEADER_LENGTH).order(ByteOrder.LITTLE_ENDIAN);
messageHeader.putInt(compressedMessage.getSerializedSize() + XMessageHeader.MESSAGE_TYPE_LENGTH);
messageHeader.put((byte) ClientMessages.Type.COMPRESSION_VALUE);
this.out.write(messageHeader.array());
compressedMessage.writeTo(this.out);
this.out.flush();
this.compressionEnabled = false;
}
Arrays.fill(this.frameHeader, (byte) 0);
this.frameHeaderBuffered = 0;
this.frameHeaderDumped = 0;
this.framePayloadLength = 0;
this.framePayloadDumped = 0;
this.xMessageHeader = null;
}
}
/**
* Ensures that this {@link OutputStream} wasn't closed yet.
*
* @throws IOException
* if this {@link OutputStream} was closed.
*/
private void ensureOpen() throws IOException {
if (this.closed) {
throw new IOException("Stream closed");
}
}
}
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