org.apache.hudi.org.apache.hadoop.hbase.zookeeper.ZKMetadata Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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 org.apache.hadoop.hbase.zookeeper;
import java.util.concurrent.ThreadLocalRandom;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.yetus.audience.InterfaceAudience;
/**
* The metadata append to the start of data on zookeeper.
*/
@InterfaceAudience.Private
public class ZKMetadata {
private ZKMetadata() {
}
// The metadata attached to each piece of data has the format:
// 1-byte constant
// 4-byte big-endian integer (length of next field)
// identifier corresponding uniquely to this process
// It is prepended to the data supplied by the user.
// the magic number is to be backward compatible
private static final byte MAGIC = (byte) 0XFF;
private static final int MAGIC_SIZE = Bytes.SIZEOF_BYTE;
private static final int ID_LENGTH_OFFSET = MAGIC_SIZE;
private static final int ID_LENGTH_SIZE = Bytes.SIZEOF_INT;
public static byte[] appendMetaData(byte[] id, byte[] data) {
if (data == null || data.length == 0) {
return data;
}
byte[] salt = Bytes.toBytes(ThreadLocalRandom.current().nextLong());
int idLength = id.length + salt.length;
byte[] newData = new byte[MAGIC_SIZE + ID_LENGTH_SIZE + idLength + data.length];
int pos = 0;
pos = Bytes.putByte(newData, pos, MAGIC);
pos = Bytes.putInt(newData, pos, idLength);
pos = Bytes.putBytes(newData, pos, id, 0, id.length);
pos = Bytes.putBytes(newData, pos, salt, 0, salt.length);
pos = Bytes.putBytes(newData, pos, data, 0, data.length);
return newData;
}
public static byte[] removeMetaData(byte[] data) {
if (data == null || data.length == 0) {
return data;
}
// check the magic data; to be backward compatible
byte magic = data[0];
if (magic != MAGIC) {
return data;
}
int idLength = Bytes.toInt(data, ID_LENGTH_OFFSET);
int dataLength = data.length - MAGIC_SIZE - ID_LENGTH_SIZE - idLength;
int dataOffset = MAGIC_SIZE + ID_LENGTH_SIZE + idLength;
byte[] newData = new byte[dataLength];
System.arraycopy(data, dataOffset, newData, 0, dataLength);
return newData;
}
}