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* distributed with this work for additional information
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* 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,
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* KIND, either express or implied. See the License for the
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package org.apache.cassandra.utils;
import java.math.BigInteger;
import java.util.*;
import org.apache.cassandra.utils.AbstractIterator;
import org.junit.Before;
import org.junit.Test;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.dht.IPartitioner;
import org.apache.cassandra.dht.RandomPartitioner;
import org.apache.cassandra.dht.RandomPartitioner.BigIntegerToken;
import org.apache.cassandra.dht.Range;
import org.apache.cassandra.dht.Token;
import org.apache.cassandra.io.util.DataInputBuffer;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.DataOutputBuffer;
import org.apache.cassandra.net.MessagingService;
import org.apache.cassandra.utils.MerkleTree.Hashable;
import org.apache.cassandra.utils.MerkleTree.RowHash;
import org.apache.cassandra.utils.MerkleTree.TreeRange;
import org.apache.cassandra.utils.MerkleTree.TreeRangeIterator;
import static org.apache.cassandra.utils.MerkleTree.RECOMMENDED_DEPTH;
import static org.junit.Assert.*;
public class MerkleTreeTest
{
public static byte[] DUMMY = "blah".getBytes();
/**
* If a test assumes that the tree is 8 units wide, then it should set this value
* to 8.
*/
public static BigInteger TOKEN_SCALE = new BigInteger("8");
protected IPartitioner partitioner;
protected MerkleTree mt;
private Range<Token> fullRange()
{
return new Range<>(partitioner.getMinimumToken(), partitioner.getMinimumToken());
}
@Before
public void clear()
{
TOKEN_SCALE = new BigInteger("8");
partitioner = RandomPartitioner.instance;
// TODO need to trickle TokenSerializer
DatabaseDescriptor.setPartitionerUnsafe(partitioner);
mt = new MerkleTree(partitioner, fullRange(), RECOMMENDED_DEPTH, Integer.MAX_VALUE);
}
public static void assertHashEquals(final byte[] left, final byte[] right)
{
assertHashEquals("", left, right);
}
public static void assertHashEquals(String message, final byte[] left, final byte[] right)
{
String lstring = left == null ? "null" : Hex.bytesToHex(left);
String rstring = right == null ? "null" : Hex.bytesToHex(right);
assertEquals(message, lstring, rstring);
}
/**
* The value returned by this method is affected by TOKEN_SCALE: setting TOKEN_SCALE
* to 8 means that passing -1 through 8 for this method will return values mapped
* between -1 and Token.MAX_VALUE.
*/
public static Token tok(int i)
{
if (i == -1)
return new BigIntegerToken(new BigInteger("-1"));
BigInteger bint = RandomPartitioner.MAXIMUM.divide(TOKEN_SCALE).multiply(new BigInteger(""+i));
return new BigIntegerToken(bint);
}
@Test
public void testSplit()
{
// split the range (zero, zero] into:
// (zero,four], (four,six], (six,seven] and (seven, zero]
mt.split(tok(4));
mt.split(tok(6));
mt.split(tok(7));
assertEquals(4, mt.size());
assertEquals(new Range<>(tok(7), tok(-1)), mt.get(tok(-1)));
assertEquals(new Range<>(tok(-1), tok(4)), mt.get(tok(3)));
assertEquals(new Range<>(tok(-1), tok(4)), mt.get(tok(4)));
assertEquals(new Range<>(tok(4), tok(6)), mt.get(tok(6)));
assertEquals(new Range<>(tok(6), tok(7)), mt.get(tok(7)));
// check depths
assertEquals((byte)1, mt.get(tok(4)).depth);
assertEquals((byte)2, mt.get(tok(6)).depth);
assertEquals((byte)3, mt.get(tok(7)).depth);
assertEquals((byte)3, mt.get(tok(-1)).depth);
try
{
mt.split(tok(-1));
fail("Shouldn't be able to split outside the initial range.");
}
catch (AssertionError e)
{
// pass
}
}
@Test
public void testSplitLimitDepth()
{
mt = new MerkleTree(partitioner, fullRange(), (byte)2, Integer.MAX_VALUE);
assertTrue(mt.split(tok(4)));
assertTrue(mt.split(tok(2)));
assertEquals(3, mt.size());
// should fail to split below hashdepth
assertFalse(mt.split(tok(1)));
assertEquals(3, mt.size());
assertEquals(new Range<>(tok(4), tok(-1)), mt.get(tok(-1)));
assertEquals(new Range<>(tok(-1), tok(2)), mt.get(tok(2)));
assertEquals(new Range<>(tok(2), tok(4)), mt.get(tok(4)));
}
@Test
public void testSplitLimitSize()
{
mt = new MerkleTree(partitioner, fullRange(), RECOMMENDED_DEPTH, 2);
assertTrue(mt.split(tok(4)));
assertEquals(2, mt.size());
// should fail to split above maxsize
assertFalse(mt.split(tok(2)));
assertEquals(2, mt.size());
assertEquals(new Range<>(tok(4), tok(-1)), mt.get(tok(-1)));
assertEquals(new Range<>(tok(-1), tok(4)), mt.get(tok(4)));
}
@Test
public void testInvalids()
{
Iterator<TreeRange> ranges;
// (zero, zero]
ranges = mt.invalids();
assertEquals(new Range<>(tok(-1), tok(-1)), ranges.next());
assertFalse(ranges.hasNext());
// all invalid
mt.split(tok(4));
mt.split(tok(2));
mt.split(tok(6));
mt.split(tok(3));
mt.split(tok(5));
ranges = mt.invalids();
assertEquals(new Range<>(tok(6), tok(-1)), ranges.next());
assertEquals(new Range<>(tok(-1), tok(2)), ranges.next());
assertEquals(new Range<>(tok(2), tok(3)), ranges.next());
assertEquals(new Range<>(tok(3), tok(4)), ranges.next());
assertEquals(new Range<>(tok(4), tok(5)), ranges.next());
assertEquals(new Range<>(tok(5), tok(6)), ranges.next());
assertEquals(new Range<>(tok(6), tok(-1)), ranges.next());
assertFalse(ranges.hasNext());
}
@Test
public void testHashFull()
{
byte[] val = DUMMY;
Range<Token> range = new Range<>(tok(-1), tok(-1));
// (zero, zero]
assertNull(mt.hash(range));
// validate the range
mt.get(tok(-1)).hash(val);
assertHashEquals(val, mt.hash(range));
}
@Test
public void testHashPartial()
{
byte[] val = DUMMY;
byte[] leftval = hashed(val, 1, 1);
byte[] partialval = hashed(val, 1);
Range<Token> left = new Range<>(tok(-1), tok(4));
Range<Token> partial = new Range<>(tok(2), tok(4));
Range<Token> right = new Range<>(tok(4), tok(-1));
Range<Token> linvalid = new Range<>(tok(1), tok(4));
Range<Token> rinvalid = new Range<>(tok(4), tok(6));
// (zero,two] (two,four] (four, zero]
mt.split(tok(4));
mt.split(tok(2));
assertNull(mt.hash(left));
assertNull(mt.hash(partial));
assertNull(mt.hash(right));
assertNull(mt.hash(linvalid));
assertNull(mt.hash(rinvalid));
// validate the range
mt.get(tok(2)).hash(val);
mt.get(tok(4)).hash(val);
mt.get(tok(-1)).hash(val);
assertHashEquals(leftval, mt.hash(left));
assertHashEquals(partialval, mt.hash(partial));
assertHashEquals(val, mt.hash(right));
assertNull(mt.hash(linvalid));
assertNull(mt.hash(rinvalid));
}
@Test
public void testHashInner()
{
byte[] val = DUMMY;
byte[] lchildval = hashed(val, 3, 3, 2);
byte[] rchildval = hashed(val, 2, 2);
byte[] fullval = hashed(val, 3, 3, 2, 2, 2);
Range<Token> full = new Range<>(tok(-1), tok(-1));
Range<Token> lchild = new Range<>(tok(-1), tok(4));
Range<Token> rchild = new Range<>(tok(4), tok(-1));
Range<Token> invalid = new Range<>(tok(1), tok(-1));
// (zero,one] (one, two] (two,four] (four, six] (six, zero]
mt.split(tok(4));
mt.split(tok(2));
mt.split(tok(6));
mt.split(tok(1));
assertNull(mt.hash(full));
assertNull(mt.hash(lchild));
assertNull(mt.hash(rchild));
assertNull(mt.hash(invalid));
// validate the range
mt.get(tok(1)).hash(val);
mt.get(tok(2)).hash(val);
mt.get(tok(4)).hash(val);
mt.get(tok(6)).hash(val);
mt.get(tok(-1)).hash(val);
assertHashEquals(fullval, mt.hash(full));
assertHashEquals(lchildval, mt.hash(lchild));
assertHashEquals(rchildval, mt.hash(rchild));
assertNull(mt.hash(invalid));
}
@Test
public void testHashDegenerate()
{
TOKEN_SCALE = new BigInteger("32");
byte[] val = DUMMY;
byte[] childfullval = hashed(val, 5, 5, 4);
byte[] fullval = hashed(val, 5, 5, 4, 3, 2, 1);
Range<Token> childfull = new Range<>(tok(-1), tok(4));
Range<Token> full = new Range<>(tok(-1), tok(-1));
Range<Token> invalid = new Range<>(tok(4), tok(-1));
mt = new MerkleTree(partitioner, fullRange(), RECOMMENDED_DEPTH, Integer.MAX_VALUE);
mt.split(tok(16));
mt.split(tok(8));
mt.split(tok(4));
mt.split(tok(2));
mt.split(tok(1));
assertNull(mt.hash(full));
assertNull(mt.hash(childfull));
assertNull(mt.hash(invalid));
// validate the range
mt.get(tok(1)).hash(val);
mt.get(tok(2)).hash(val);
mt.get(tok(4)).hash(val);
mt.get(tok(8)).hash(val);
mt.get(tok(16)).hash(val);
mt.get(tok(-1)).hash(val);
assertHashEquals(fullval, mt.hash(full));
assertHashEquals(childfullval, mt.hash(childfull));
assertNull(mt.hash(invalid));
}
@Test
public void testHashRandom()
{
int max = 1000000;
TOKEN_SCALE = new BigInteger("" + max);
mt = new MerkleTree(partitioner, fullRange(), RECOMMENDED_DEPTH, 32);
Random random = new Random();
while (true)
{
if (!mt.split(tok(random.nextInt(max))))
break;
}
// validate the tree
TreeRangeIterator ranges = mt.invalids();
for (TreeRange range : ranges)
range.addHash(new RowHash(range.right, new byte[0], 0));
assert mt.hash(new Range<>(tok(-1), tok(-1))) != null :
"Could not hash tree " + mt;
}
/**
* Generate two trees with different splits, but containing the same keys, and
* check that they compare equally.
*
* The set of keys used in this test is: #{2,4,6,8,12,14,0}
*/
@Test
public void testValidateTree()
{
TOKEN_SCALE = new BigInteger("16"); // this test needs slightly more resolution
Range<Token> full = new Range<>(tok(-1), tok(-1));
Iterator<TreeRange> ranges;
MerkleTree mt2 = new MerkleTree(partitioner, fullRange(), RECOMMENDED_DEPTH, Integer.MAX_VALUE);
mt.split(tok(8));
mt.split(tok(4));
mt.split(tok(12));
mt.split(tok(6));
mt.split(tok(10));
ranges = mt.invalids();
ranges.next().addAll(new HIterator(2, 4)); // (-1,4]: depth 2
ranges.next().addAll(new HIterator(6)); // (4,6]
ranges.next().addAll(new HIterator(8)); // (6,8]
ranges.next().addAll(new HIterator(/*empty*/ new int[0])); // (8,10]
ranges.next().addAll(new HIterator(12)); // (10,12]
ranges.next().addAll(new HIterator(14, -1)); // (12,-1]: depth 2
mt2.split(tok(8));
mt2.split(tok(4));
mt2.split(tok(12));
mt2.split(tok(2));
mt2.split(tok(10));
mt2.split(tok(9));
mt2.split(tok(11));
ranges = mt2.invalids();
ranges.next().addAll(new HIterator(2)); // (-1,2]
ranges.next().addAll(new HIterator(4)); // (2,4]
ranges.next().addAll(new HIterator(6, 8)); // (4,8]: depth 2
ranges.next().addAll(new HIterator(/*empty*/ new int[0])); // (8,9]
ranges.next().addAll(new HIterator(/*empty*/ new int[0])); // (9,10]
ranges.next().addAll(new HIterator(/*empty*/ new int[0])); // (10,11]: depth 4
ranges.next().addAll(new HIterator(12)); // (11,12]: depth 4
ranges.next().addAll(new HIterator(14, -1)); // (12,-1]: depth 2
byte[] mthash = mt.hash(full);
byte[] mt2hash = mt2.hash(full);
assertHashEquals("Tree hashes did not match: " + mt + " && " + mt2, mthash, mt2hash);
}
@Test
public void testSerialization() throws Exception
{
Range<Token> full = new Range<>(tok(-1), tok(-1));
// populate and validate the tree
mt.maxsize(256);
mt.init();
for (TreeRange range : mt.invalids())
range.addAll(new HIterator(range.right));
byte[] initialhash = mt.hash(full);
DataOutputBuffer out = new DataOutputBuffer();
MerkleTree.serializer.serialize(mt, out, MessagingService.current_version);
byte[] serialized = out.toByteArray();
DataInputPlus in = new DataInputBuffer(serialized);
MerkleTree restored = MerkleTree.serializer.deserialize(in, MessagingService.current_version);
assertHashEquals(initialhash, restored.hash(full));
}
@Test
public void testDifference()
{
int maxsize = 16;
mt.maxsize(maxsize);
MerkleTree mt2 = new MerkleTree(partitioner, fullRange(), RECOMMENDED_DEPTH, maxsize);
mt.init();
mt2.init();
// add dummy hashes to both trees
for (TreeRange range : mt.invalids())
range.addAll(new HIterator(range.right));
for (TreeRange range : mt2.invalids())
range.addAll(new HIterator(range.right));
TreeRange leftmost = null;
TreeRange middle = null;
mt.maxsize(maxsize + 2); // give some room for splitting
// split the leftmost
Iterator<TreeRange> ranges = mt.invalids();
leftmost = ranges.next();
mt.split(leftmost.right);
// set the hashes for the leaf of the created split
middle = mt.get(leftmost.right);
middle.hash("arbitrary!".getBytes());
mt.get(partitioner.midpoint(leftmost.left, leftmost.right)).hash("even more arbitrary!".getBytes());
// trees should disagree for (leftmost.left, middle.right]
List<TreeRange> diffs = MerkleTree.difference(mt, mt2);
assertEquals(diffs + " contains wrong number of differences:", 1, diffs.size());
assertTrue(diffs.contains(new Range<>(leftmost.left, middle.right)));
}
/**
* Return the root hash of a binary tree with leaves at the given depths
* and with the given hash val in each leaf.
*/
byte[] hashed(byte[] val, Integer... depths)
{
ArrayDeque<Integer> dstack = new ArrayDeque<Integer>();
ArrayDeque<byte[]> hstack = new ArrayDeque<byte[]>();
Iterator<Integer> depthiter = Arrays.asList(depths).iterator();
if (depthiter.hasNext())
{
dstack.push(depthiter.next());
hstack.push(val);
}
while (depthiter.hasNext())
{
Integer depth = depthiter.next();
byte[] hash = val;
while (depth.equals(dstack.peek()))
{
// consume the stack
hash = Hashable.binaryHash(hstack.pop(), hash);
depth = dstack.pop()-1;
}
dstack.push(depth);
hstack.push(hash);
}
assert hstack.size() == 1;
return hstack.pop();
}
static class HIterator extends AbstractIterator<RowHash>
{
private Iterator<Token> tokens;
public HIterator(int... tokens)
{
List<Token> tlist = new LinkedList<Token>();
for (int token : tokens)
tlist.add(tok(token));
this.tokens = tlist.iterator();
}
public HIterator(Token... tokens)
{
this.tokens = Arrays.asList(tokens).iterator();
}
public RowHash computeNext()
{
if (tokens.hasNext())
return new RowHash(tokens.next(), DUMMY, DUMMY.length);
return endOfData();
}
}
}