/*
* Copyright 2012 Matt Corallo
* Copyright 2015 Andreas Schildbach
*
* 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 org.bitcoinj.core;
import com.google.common.base.Objects;
import java.io.IOException;
import java.io.OutputStream;
import java.util.*;
/**
* <p>A FilteredBlock is used to relay a block with its transactions filtered using a {@link BloomFilter}. It consists
* of the block header and a {@link PartialMerkleTree} which contains the transactions which matched the filter.</p>
*
* <p>Instances of this class are not safe for use by multiple threads.</p>
*/
public class FilteredBlock extends Message {
private Block header;
private PartialMerkleTree merkleTree;
private List<Sha256Hash> cachedTransactionHashes = null;
// A set of transactions whose hashes are a subset of getTransactionHashes()
// These were relayed as a part of the filteredblock getdata, ie likely weren't previously received as loose transactions
private Map<Sha256Hash, Transaction> associatedTransactions = new HashMap<Sha256Hash, Transaction>();
public FilteredBlock(NetworkParameters params, byte[] payloadBytes) throws ProtocolException {
super(params, payloadBytes, 0);
}
public FilteredBlock(NetworkParameters params, Block header, PartialMerkleTree pmt) {
super(params);
this.header = header;
this.merkleTree = pmt;
}
@Override
public void bitcoinSerializeToStream(OutputStream stream) throws IOException {
if (header.transactions == null)
header.bitcoinSerializeToStream(stream);
else
header.cloneAsHeader().bitcoinSerializeToStream(stream);
merkleTree.bitcoinSerializeToStream(stream);
}
@Override
protected void parse() throws ProtocolException {
byte[] headerBytes = new byte[Block.HEADER_SIZE];
System.arraycopy(payload, 0, headerBytes, 0, Block.HEADER_SIZE);
header = params.getDefaultSerializer().makeBlock(headerBytes);
merkleTree = new PartialMerkleTree(params, payload, Block.HEADER_SIZE);
length = Block.HEADER_SIZE + merkleTree.getMessageSize();
}
/**
* Gets a list of leaf hashes which are contained in the partial merkle tree in this filtered block
*
* @throws ProtocolException If the partial merkle block is invalid or the merkle root of the partial merkle block doesnt match the block header
*/
public List<Sha256Hash> getTransactionHashes() throws VerificationException {
if (cachedTransactionHashes != null)
return Collections.unmodifiableList(cachedTransactionHashes);
List<Sha256Hash> hashesMatched = new LinkedList<Sha256Hash>();
if (header.getMerkleRoot().equals(merkleTree.getTxnHashAndMerkleRoot(hashesMatched))) {
cachedTransactionHashes = hashesMatched;
return Collections.unmodifiableList(cachedTransactionHashes);
} else
throw new VerificationException("Merkle root of block header does not match merkle root of partial merkle tree.");
}
/**
* Gets a copy of the block header
*/
public Block getBlockHeader() {
return header.cloneAsHeader();
}
/** Gets the hash of the block represented in this Filtered Block */
@Override
public Sha256Hash getHash() {
return header.getHash();
}
/**
* Provide this FilteredBlock with a transaction which is in its Merkle tree.
* @return false if the tx is not relevant to this FilteredBlock
*/
public boolean provideTransaction(Transaction tx) throws VerificationException {
Sha256Hash hash = tx.getHash();
if (getTransactionHashes().contains(hash)) {
associatedTransactions.put(hash, tx);
return true;
}
return false;
}
/** Returns the {@link PartialMerkleTree} object that provides the mathematical proof of transaction inclusion in the block. */
public PartialMerkleTree getPartialMerkleTree() {
return merkleTree;
}
/** Gets the set of transactions which were provided using provideTransaction() which match in getTransactionHashes() */
public Map<Sha256Hash, Transaction> getAssociatedTransactions() {
return Collections.unmodifiableMap(associatedTransactions);
}
/** Number of transactions in this block, before it was filtered */
public int getTransactionCount() {
return merkleTree.getTransactionCount();
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
FilteredBlock other = (FilteredBlock) o;
return associatedTransactions.equals(other.associatedTransactions)
&& header.equals(other.header) && merkleTree.equals(other.merkleTree);
}
@Override
public int hashCode() {
return Objects.hashCode(associatedTransactions, header, merkleTree);
}
@Override
public String toString() {
return "FilteredBlock{merkleTree=" + merkleTree + ", header=" + header + '}';
}
}