/**
* Copyright 2011 Google 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.google.devcoin.core;
import com.google.devcoin.script.Script;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.Serializable;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
/**
* This message is a reference or pointer to an output of a different transaction.
*/
public class TransactionOutPoint extends ChildMessage implements Serializable {
private static final long serialVersionUID = -6320880638344662579L;
static final int MESSAGE_LENGTH = 36;
/** Hash of the transaction to which we refer. */
private Sha256Hash hash;
/** Which output of that transaction we are talking about. */
private long index;
// This is not part of Bitcoin serialization. It's included in Java serialization.
// It points to the connected transaction.
Transaction fromTx;
public TransactionOutPoint(NetworkParameters params, long index, Transaction fromTx) {
super(params);
this.index = index;
if (fromTx != null) {
this.hash = fromTx.getHash();
this.fromTx = fromTx;
} else {
// This happens when constructing the genesis block.
hash = Sha256Hash.ZERO_HASH;
}
length = MESSAGE_LENGTH;
}
public TransactionOutPoint(NetworkParameters params, long index, Sha256Hash hash) {
super(params);
this.index = index;
this.hash = hash;
length = MESSAGE_LENGTH;
}
/**
/**
* Deserializes the message. This is usually part of a transaction message.
*/
public TransactionOutPoint(NetworkParameters params, byte[] payload, int offset) throws ProtocolException {
super(params, payload, offset);
}
/**
* Deserializes the message. This is usually part of a transaction message.
* @param params NetworkParameters object.
* @param offset The location of the first msg byte within the array.
* @param parseLazy Whether to perform a full parse immediately or delay until a read is requested.
* @param parseRetain Whether to retain the backing byte array for quick reserialization.
* If true and the backing byte array is invalidated due to modification of a field then
* the cached bytes may be repopulated and retained if the message is serialized again in the future.
* @throws ProtocolException
*/
public TransactionOutPoint(NetworkParameters params, byte[] payload, int offset, Message parent, boolean parseLazy, boolean parseRetain) throws ProtocolException {
super(params, payload, offset, parent, parseLazy, parseRetain, MESSAGE_LENGTH);
}
protected void parseLite() throws ProtocolException {
length = MESSAGE_LENGTH;
}
@Override
void parse() throws ProtocolException {
hash = readHash();
index = readUint32();
}
/* (non-Javadoc)
* @see Message#getMessageSize()
*/
@Override
public int getMessageSize() {
return MESSAGE_LENGTH;
}
@Override
protected void bitcoinSerializeToStream(OutputStream stream) throws IOException {
stream.write(Utils.reverseBytes(hash.getBytes()));
Utils.uint32ToByteStreamLE(index, stream);
}
/**
* An outpoint is a part of a transaction input that points to the output of another transaction. If we have both
* sides in memory, and they have been linked together, this returns a pointer to the connected output, or null
* if there is no such connection.
*/
public TransactionOutput getConnectedOutput() {
if (fromTx == null) return null;
return fromTx.getOutputs().get((int) index);
}
/**
* Returns the pubkey script from the connected output.
*/
byte[] getConnectedPubKeyScript() {
byte[] result = checkNotNull(getConnectedOutput().getScriptBytes());
checkState(result.length > 0);
return result;
}
/**
* Convenience method to get the connected outputs pubkey hash.
*/
byte[] getConnectedPubKeyHash() throws ScriptException {
return getConnectedOutput().getScriptPubKey().getPubKeyHash();
}
/**
* Returns the ECKey identified in the connected output, for either pay-to-address scripts or pay-to-key scripts.
* If the script forms cannot be understood, throws ScriptException.
* @return an ECKey or null if the connected key cannot be found in the wallet.
*/
public ECKey getConnectedKey(Wallet wallet) throws ScriptException {
TransactionOutput connectedOutput = getConnectedOutput();
checkNotNull(connectedOutput, "Input is not connected so cannot retrieve key");
Script connectedScript = connectedOutput.getScriptPubKey();
if (connectedScript.isSentToAddress()) {
byte[] addressBytes = connectedScript.getPubKeyHash();
return wallet.findKeyFromPubHash(addressBytes);
} else if (connectedScript.isSentToRawPubKey()) {
byte[] pubkeyBytes = connectedScript.getPubKey();
return wallet.findKeyFromPubKey(pubkeyBytes);
} else {
throw new ScriptException("Could not understand form of connected output script: " + connectedScript);
}
}
@Override
public String toString() {
return hash.toString() + ":" + index;
}
/**
* Returns the hash of the transaction this outpoint references/spends/is connected to.
*/
public Sha256Hash getHash() {
maybeParse();
return hash;
}
void setHash(Sha256Hash hash) {
this.hash = hash;
}
public long getIndex() {
maybeParse();
return index;
}
public void setIndex(long index) {
this.index = index;
}
/**
* Ensure object is fully parsed before invoking java serialization. The backing byte array
* is transient so if the object has parseLazy = true and hasn't invoked checkParse yet
* then data will be lost during serialization.
*/
private void writeObject(ObjectOutputStream out) throws IOException {
maybeParse();
out.defaultWriteObject();
}
@Override
public boolean equals(Object other) {
if (!(other instanceof TransactionOutPoint)) return false;
TransactionOutPoint o = (TransactionOutPoint) other;
return o.getIndex() == getIndex() && o.getHash().equals(getHash());
}
@Override
public int hashCode() {
return getHash().hashCode();
}
}