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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.cassandra.db;
import java.nio.ByteBuffer;
import com.google.common.hash.Hasher;
import com.google.common.hash.Hashing;
import org.apache.cassandra.db.context.CounterContext;
import org.apache.cassandra.utils.FastByteOperations;
public class Digest
{
private static final ThreadLocal localBuffer = ThreadLocal.withInitial(() -> new byte[4096]);
private final Hasher hasher;
private long inputBytes = 0;
@SuppressWarnings("deprecation")
private static Hasher md5()
{
return Hashing.md5().newHasher();
}
public static Digest forReadResponse()
{
return new Digest(md5());
}
public static Digest forSchema()
{
return new Digest(md5());
}
public static Digest forValidator()
{
// Uses a Hasher that concatenates the hash code from 2 hash functions
// (murmur3_128) with different seeds to produce a 256 bit hashcode
return new Digest(Hashing.concatenating(Hashing.murmur3_128(1000),
Hashing.murmur3_128(2000))
.newHasher());
}
public static Digest forRepairedDataTracking()
{
return new Digest(Hashing.crc32c().newHasher())
{
@Override
public Digest updateWithCounterContext(ByteBuffer context)
{
// for the purposes of repaired data tracking on the read path, exclude
// contexts with legacy shards as these may be irrevocably different on
// different replicas
if (CounterContext.instance().hasLegacyShards(context))
return this;
return super.updateWithCounterContext(context);
}
};
}
Digest(Hasher hasher)
{
this.hasher = hasher;
}
public Digest update(byte[] input, int offset, int len)
{
hasher.putBytes(input, offset, len);
inputBytes += len;
return this;
}
/**
* Update the digest with the bytes from the supplied buffer. This does
* not modify the position of the supplied buffer, so callers are not
* required to duplicate() the source buffer before calling
*/
public Digest update(ByteBuffer input)
{
return update(input, input.position(), input.remaining());
}
/**
* Update the digest with the bytes sliced from the supplied buffer. This does
* not modify the position of the supplied buffer, so callers are not
* required to duplicate() the source buffer before calling
*/
private Digest update(ByteBuffer input, int pos, int len)
{
if (len <= 0)
return this;
if (input.hasArray())
{
byte[] b = input.array();
int ofs = input.arrayOffset();
hasher.putBytes(b, ofs + pos, len);
inputBytes += len;
}
else
{
byte[] tempArray = localBuffer.get();
while (len > 0)
{
int chunk = Math.min(len, tempArray.length);
FastByteOperations.copy(input, pos, tempArray, 0, chunk);
hasher.putBytes(tempArray, 0, chunk);
len -= chunk;
pos += chunk;
inputBytes += chunk;
}
}
return this;
}
/**
* Update the digest with the content of a counter context.
* Note that this skips the header entirely since the header information
* has local meaning only, while digests are meant for comparison across
* nodes. This means in particular that we always have:
* updateDigest(ctx) == updateDigest(clearAllLocal(ctx))
*/
public Digest updateWithCounterContext(ByteBuffer context)
{
// context can be empty due to the optimization from CASSANDRA-10657
if (!context.hasRemaining())
return this;
int pos = context.position() + CounterContext.headerLength(context);
int len = context.limit() - pos;
update(context, pos, len);
return this;
}
public Digest updateWithByte(int val)
{
hasher.putByte((byte) (val & 0xFF));
inputBytes++;
return this;
}
public Digest updateWithInt(int val)
{
hasher.putByte((byte) ((val >>> 24) & 0xFF));
hasher.putByte((byte) ((val >>> 16) & 0xFF));
hasher.putByte((byte) ((val >>> 8) & 0xFF));
hasher.putByte((byte) ((val >>> 0) & 0xFF));
inputBytes += 4;
return this;
}
public Digest updateWithLong(long val)
{
hasher.putByte((byte) ((val >>> 56) & 0xFF));
hasher.putByte((byte) ((val >>> 48) & 0xFF));
hasher.putByte((byte) ((val >>> 40) & 0xFF));
hasher.putByte((byte) ((val >>> 32) & 0xFF));
hasher.putByte((byte) ((val >>> 24) & 0xFF));
hasher.putByte((byte) ((val >>> 16) & 0xFF));
hasher.putByte((byte) ((val >>> 8) & 0xFF));
hasher.putByte((byte) ((val >>> 0) & 0xFF));
inputBytes += 8;
return this;
}
public Digest updateWithBoolean(boolean val)
{
updateWithByte(val ? 0 : 1);
return this;
}
public byte[] digest()
{
return hasher.hash().asBytes();
}
public long inputBytes()
{
return inputBytes;
}
}