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The MongoDB Java Driver uber-artifact, containing the legacy driver, the mongodb-driver, mongodb-driver-core, and bson
/*
* Copyright 2008-present MongoDB, Inc.
*
* Licensed 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 com.mongodb.connection;
import org.bson.ByteBuf;
import org.bson.io.OutputBuffer;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteOrder;
import java.util.ArrayList;
import java.util.List;
import static com.mongodb.assertions.Assertions.notNull;
/**
* This class should not be considered as part of the public API, and it may change or be removed at any time.
*
*/
public class ByteBufferBsonOutput extends OutputBuffer {
private static final int MAX_SHIFT = 31;
private static final int INITIAL_SHIFT = 10;
public static final int INITIAL_BUFFER_SIZE = 1 << INITIAL_SHIFT;
public static final int MAX_BUFFER_SIZE = 1 << 24;
private final BufferProvider bufferProvider;
private final List bufferList = new ArrayList();
private int curBufferIndex = 0;
private int position = 0;
private boolean closed;
/**
* Construct an instance that uses the given buffer provider to allocate byte buffers as needs as it grows.
*
* @param bufferProvider the non-null buffer provider
*/
public ByteBufferBsonOutput(final BufferProvider bufferProvider) {
this.bufferProvider = notNull("bufferProvider", bufferProvider);
}
@Override
public void writeBytes(final byte[] bytes, final int offset, final int length) {
ensureOpen();
int currentOffset = offset;
int remainingLen = length;
while (remainingLen > 0) {
ByteBuf buf = getCurrentByteBuffer();
int bytesToPutInCurrentBuffer = Math.min(buf.remaining(), remainingLen);
buf.put(bytes, currentOffset, bytesToPutInCurrentBuffer);
remainingLen -= bytesToPutInCurrentBuffer;
currentOffset += bytesToPutInCurrentBuffer;
}
position += length;
}
@Override
public void writeByte(final int value) {
ensureOpen();
getCurrentByteBuffer().put((byte) value);
position++;
}
private ByteBuf getCurrentByteBuffer() {
ByteBuf curByteBuffer = getByteBufferAtIndex(curBufferIndex);
if (curByteBuffer.hasRemaining()) {
return curByteBuffer;
}
curBufferIndex++;
return getByteBufferAtIndex(curBufferIndex);
}
private ByteBuf getByteBufferAtIndex(final int index) {
if (bufferList.size() < index + 1) {
bufferList.add(bufferProvider.getBuffer(index >= (MAX_SHIFT - INITIAL_SHIFT)
? MAX_BUFFER_SIZE
: Math.min(INITIAL_BUFFER_SIZE << index, MAX_BUFFER_SIZE)));
}
return bufferList.get(index);
}
@Override
public int getPosition() {
ensureOpen();
return position;
}
@Override
public int getSize() {
ensureOpen();
return position;
}
protected void write(final int absolutePosition, final int value) {
ensureOpen();
if (absolutePosition < 0) {
throw new IllegalArgumentException(String.format("position must be >= 0 but was %d", absolutePosition));
}
if (absolutePosition > position - 1) {
throw new IllegalArgumentException(String.format("position must be <= %d but was %d", position - 1, absolutePosition));
}
BufferPositionPair bufferPositionPair = getBufferPositionPair(absolutePosition);
ByteBuf byteBuffer = getByteBufferAtIndex(bufferPositionPair.bufferIndex);
byteBuffer.put(bufferPositionPair.position++, (byte) value);
}
@Override
public List getByteBuffers() {
ensureOpen();
List buffers = new ArrayList(bufferList.size());
for (final ByteBuf cur : bufferList) {
buffers.add(cur.duplicate().order(ByteOrder.LITTLE_ENDIAN).flip());
}
return buffers;
}
@Override
public int pipe(final OutputStream out) throws IOException {
ensureOpen();
byte[] tmp = new byte[INITIAL_BUFFER_SIZE];
int total = 0;
for (final ByteBuf cur : getByteBuffers()) {
ByteBuf dup = cur.duplicate();
while (dup.hasRemaining()) {
int numBytesToCopy = Math.min(dup.remaining(), tmp.length);
dup.get(tmp, 0, numBytesToCopy);
out.write(tmp, 0, numBytesToCopy);
}
total += dup.limit();
}
return total;
}
@Override
public void truncateToPosition(final int newPosition) {
ensureOpen();
if (newPosition > position || newPosition < 0) {
throw new IllegalArgumentException();
}
BufferPositionPair bufferPositionPair = getBufferPositionPair(newPosition);
bufferList.get(bufferPositionPair.bufferIndex).position(bufferPositionPair.position);
while (bufferList.size() > bufferPositionPair.bufferIndex + 1) {
ByteBuf buffer = bufferList.remove(bufferList.size() - 1);
buffer.release();
}
curBufferIndex = bufferPositionPair.bufferIndex;
position = newPosition;
}
@Override
public void close() {
for (final ByteBuf cur : bufferList) {
cur.release();
}
bufferList.clear();
closed = true;
}
private BufferPositionPair getBufferPositionPair(final int absolutePosition) {
int positionInBuffer = absolutePosition;
int bufferIndex = 0;
int bufferSize = INITIAL_BUFFER_SIZE;
int startPositionOfBuffer = 0;
while (startPositionOfBuffer + bufferSize <= absolutePosition) {
bufferIndex++;
startPositionOfBuffer += bufferSize;
positionInBuffer -= bufferSize;
bufferSize = bufferList.get(bufferIndex).limit();
}
return new BufferPositionPair(bufferIndex, positionInBuffer);
}
private void ensureOpen() {
if (closed) {
throw new IllegalStateException("The output is closed");
}
}
private static final class BufferPositionPair {
private final int bufferIndex;
private int position;
BufferPositionPair(final int bufferIndex, final int position) {
this.bufferIndex = bufferIndex;
this.position = position;
}
}
}