/*
* Copyright 2011 Google Inc.
* Copyright 2014 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 org.bitcoinj.script.Script;
import org.bitcoinj.wallet.DefaultRiskAnalysis;
import org.bitcoinj.wallet.KeyBag;
import org.bitcoinj.wallet.RedeemData;
import com.google.common.base.Joiner;
import com.google.common.base.Objects;
import javax.annotation.Nullable;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.ref.WeakReference;
import java.util.Arrays;
import java.util.Map;
import static com.google.common.base.Preconditions.checkElementIndex;
import static com.google.common.base.Preconditions.checkNotNull;
/**
* <p>A transfer of coins from one address to another creates a transaction in which the outputs
* can be claimed by the recipient in the input of another transaction. You can imagine a
* transaction as being a module which is wired up to others, the inputs of one have to be wired
* to the outputs of another. The exceptions are coinbase transactions, which create new coins.</p>
*
* <p>Instances of this class are not safe for use by multiple threads.</p>
*/
public class TransactionInput extends ChildMessage {
/** Magic sequence number that indicates there is no sequence number. */
public static final long NO_SEQUENCE = 0xFFFFFFFFL;
private static final byte[] EMPTY_ARRAY = new byte[0];
// Magic outpoint index that indicates the input is in fact unconnected.
private static final long UNCONNECTED = 0xFFFFFFFFL;
// Allows for altering transactions after they were broadcast. Values below NO_SEQUENCE-1 mean it can be altered.
private long sequence;
// Data needed to connect to the output of the transaction we're gathering coins from.
private TransactionOutPoint outpoint;
// The "script bytes" might not actually be a script. In coinbase transactions where new coins are minted there
// is no input transaction, so instead the scriptBytes contains some extra stuff (like a rollover nonce) that we
// don't care about much. The bytes are turned into a Script object (cached below) on demand via a getter.
private byte[] scriptBytes;
// The Script object obtained from parsing scriptBytes. Only filled in on demand and if the transaction is not
// coinbase.
private WeakReference<Script> scriptSig;
/** Value of the output connected to the input, if known. This field does not participate in equals()/hashCode(). */
@Nullable
private Coin value;
/**
* Creates an input that connects to nothing - used only in creation of coinbase transactions.
*/
public TransactionInput(NetworkParameters params, @Nullable Transaction parentTransaction, byte[] scriptBytes) {
this(params, parentTransaction, scriptBytes, new TransactionOutPoint(params, UNCONNECTED, (Transaction) null));
}
public TransactionInput(NetworkParameters params, @Nullable Transaction parentTransaction, byte[] scriptBytes,
TransactionOutPoint outpoint) {
this(params, parentTransaction, scriptBytes, outpoint, null);
}
public TransactionInput(NetworkParameters params, @Nullable Transaction parentTransaction, byte[] scriptBytes,
TransactionOutPoint outpoint, @Nullable Coin value) {
super(params);
this.scriptBytes = scriptBytes;
this.outpoint = outpoint;
this.sequence = NO_SEQUENCE;
this.value = value;
setParent(parentTransaction);
length = 40 + (scriptBytes == null ? 1 : VarInt.sizeOf(scriptBytes.length) + scriptBytes.length);
}
/**
* Creates an UNSIGNED input that links to the given output
*/
TransactionInput(NetworkParameters params, Transaction parentTransaction, TransactionOutput output) {
super(params);
long outputIndex = output.getIndex();
if(output.getParentTransaction() != null ) {
outpoint = new TransactionOutPoint(params, outputIndex, output.getParentTransaction());
} else {
outpoint = new TransactionOutPoint(params, output);
}
scriptBytes = EMPTY_ARRAY;
sequence = NO_SEQUENCE;
setParent(parentTransaction);
this.value = output.getValue();
length = 41;
}
/**
* Deserializes an input message. This is usually part of a transaction message.
*/
public TransactionInput(NetworkParameters params, @Nullable Transaction parentTransaction, byte[] payload, int offset) throws ProtocolException {
super(params, payload, offset);
setParent(parentTransaction);
this.value = null;
}
/**
* Deserializes an input message. This is usually part of a transaction message.
* @param params NetworkParameters object.
* @param payload Bitcoin protocol formatted byte array containing message content.
* @param offset The location of the first payload byte within the array.
* @param serializer the serializer to use for this message.
* @throws ProtocolException
*/
public TransactionInput(NetworkParameters params, Transaction parentTransaction, byte[] payload, int offset, MessageSerializer serializer)
throws ProtocolException {
super(params, payload, offset, parentTransaction, serializer, UNKNOWN_LENGTH);
this.value = null;
}
@Override
protected void parse() throws ProtocolException {
outpoint = new TransactionOutPoint(params, payload, cursor, this, serializer);
cursor += outpoint.getMessageSize();
int scriptLen = (int) readVarInt();
length = cursor - offset + scriptLen + 4;
scriptBytes = readBytes(scriptLen);
sequence = readUint32();
}
@Override
protected void bitcoinSerializeToStream(OutputStream stream) throws IOException {
outpoint.bitcoinSerialize(stream);
stream.write(new VarInt(scriptBytes.length).encode());
stream.write(scriptBytes);
Utils.uint32ToByteStreamLE(sequence, stream);
}
/**
* Coinbase transactions have special inputs with hashes of zero. If this is such an input, returns true.
*/
public boolean isCoinBase() {
return outpoint.getHash().equals(Sha256Hash.ZERO_HASH) &&
(outpoint.getIndex() & 0xFFFFFFFFL) == 0xFFFFFFFFL; // -1 but all is serialized to the wire as unsigned int.
}
/**
* Returns the script that is fed to the referenced output (scriptPubKey) script in order to satisfy it: usually
* contains signatures and maybe keys, but can contain arbitrary data if the output script accepts it.
*/
public Script getScriptSig() throws ScriptException {
// Transactions that generate new coins don't actually have a script. Instead this
// parameter is overloaded to be something totally different.
Script script = scriptSig == null ? null : scriptSig.get();
if (script == null) {
script = new Script(scriptBytes);
scriptSig = new WeakReference<Script>(script);
}
return script;
}
/** Set the given program as the scriptSig that is supposed to satisfy the connected output script. */
public void setScriptSig(Script scriptSig) {
this.scriptSig = new WeakReference<Script>(checkNotNull(scriptSig));
// TODO: This should all be cleaned up so we have a consistent internal representation.
setScriptBytes(scriptSig.getProgram());
}
/**
* Convenience method that returns the from address of this input by parsing the scriptSig. The concept of a
* "from address" is not well defined in Bitcoin and you should not assume that senders of a transaction can
* actually receive coins on the same address they used to sign (e.g. this is not true for shared wallets).
*/
@Deprecated
public Address getFromAddress() throws ScriptException {
if (isCoinBase()) {
throw new ScriptException(
"This is a coinbase transaction which generates new coins. It does not have a from address.");
}
return getScriptSig().getFromAddress(params);
}
/**
* Sequence numbers allow participants in a multi-party transaction signing protocol to create new versions of the
* transaction independently of each other. Newer versions of a transaction can replace an existing version that's
* in nodes memory pools if the existing version is time locked. See the Contracts page on the Bitcoin wiki for
* examples of how you can use this feature to build contract protocols.
*/
public long getSequenceNumber() {
return sequence;
}
/**
* Sequence numbers allow participants in a multi-party transaction signing protocol to create new versions of the
* transaction independently of each other. Newer versions of a transaction can replace an existing version that's
* in nodes memory pools if the existing version is time locked. See the Contracts page on the Bitcoin wiki for
* examples of how you can use this feature to build contract protocols.
*/
public void setSequenceNumber(long sequence) {
unCache();
this.sequence = sequence;
}
/**
* @return The previous output transaction reference, as an OutPoint structure. This contains the
* data needed to connect to the output of the transaction we're gathering coins from.
*/
public TransactionOutPoint getOutpoint() {
return outpoint;
}
/**
* The "script bytes" might not actually be a script. In coinbase transactions where new coins are minted there
* is no input transaction, so instead the scriptBytes contains some extra stuff (like a rollover nonce) that we
* don't care about much. The bytes are turned into a Script object (cached below) on demand via a getter.
* @return the scriptBytes
*/
public byte[] getScriptBytes() {
return scriptBytes;
}
/** Clear input scripts, e.g. in preparation for signing. */
public void clearScriptBytes() {
setScriptBytes(TransactionInput.EMPTY_ARRAY);
}
/**
* @param scriptBytes the scriptBytes to set
*/
void setScriptBytes(byte[] scriptBytes) {
unCache();
this.scriptSig = null;
int oldLength = length;
this.scriptBytes = scriptBytes;
// 40 = previous_outpoint (36) + sequence (4)
int newLength = 40 + (scriptBytes == null ? 1 : VarInt.sizeOf(scriptBytes.length) + scriptBytes.length);
adjustLength(newLength - oldLength);
}
/**
* @return The Transaction that owns this input.
*/
public Transaction getParentTransaction() {
return (Transaction) parent;
}
/**
* @return Value of the output connected to this input, if known. Null if unknown.
*/
@Nullable
public Coin getValue() {
return value;
}
public enum ConnectionResult {
NO_SUCH_TX,
ALREADY_SPENT,
SUCCESS
}
// TODO: Clean all this up once TransactionOutPoint disappears.
/**
* Locates the referenced output from the given pool of transactions.
*
* @return The TransactionOutput or null if the transactions map doesn't contain the referenced tx.
*/
@Nullable
TransactionOutput getConnectedOutput(Map<Sha256Hash, Transaction> transactions) {
Transaction tx = transactions.get(outpoint.getHash());
if (tx == null)
return null;
return tx.getOutputs().get((int) outpoint.getIndex());
}
/**
* Alias for getOutpoint().getConnectedRedeemData(keyBag)
* @see TransactionOutPoint#getConnectedRedeemData(org.bitcoinj.wallet.KeyBag)
*/
@Nullable
public RedeemData getConnectedRedeemData(KeyBag keyBag) throws ScriptException {
return getOutpoint().getConnectedRedeemData(keyBag);
}
public enum ConnectMode {
DISCONNECT_ON_CONFLICT,
ABORT_ON_CONFLICT
}
/**
* Connects this input to the relevant output of the referenced transaction if it's in the given map.
* Connecting means updating the internal pointers and spent flags. If the mode is to ABORT_ON_CONFLICT then
* the spent output won't be changed, but the outpoint.fromTx pointer will still be updated.
*
* @param transactions Map of txhash->transaction.
* @param mode Whether to abort if there's a pre-existing connection or not.
* @return NO_SUCH_TX if the prevtx wasn't found, ALREADY_SPENT if there was a conflict, SUCCESS if not.
*/
public ConnectionResult connect(Map<Sha256Hash, Transaction> transactions, ConnectMode mode) {
Transaction tx = transactions.get(outpoint.getHash());
if (tx == null) {
return TransactionInput.ConnectionResult.NO_SUCH_TX;
}
return connect(tx, mode);
}
/**
* Connects this input to the relevant output of the referenced transaction.
* Connecting means updating the internal pointers and spent flags. If the mode is to ABORT_ON_CONFLICT then
* the spent output won't be changed, but the outpoint.fromTx pointer will still be updated.
*
* @param transaction The transaction to try.
* @param mode Whether to abort if there's a pre-existing connection or not.
* @return NO_SUCH_TX if transaction is not the prevtx, ALREADY_SPENT if there was a conflict, SUCCESS if not.
*/
public ConnectionResult connect(Transaction transaction, ConnectMode mode) {
if (!transaction.getHash().equals(outpoint.getHash()))
return ConnectionResult.NO_SUCH_TX;
checkElementIndex((int) outpoint.getIndex(), transaction.getOutputs().size(), "Corrupt transaction");
TransactionOutput out = transaction.getOutput((int) outpoint.getIndex());
if (!out.isAvailableForSpending()) {
if (getParentTransaction().equals(outpoint.fromTx)) {
// Already connected.
return ConnectionResult.SUCCESS;
} else if (mode == ConnectMode.DISCONNECT_ON_CONFLICT) {
out.markAsUnspent();
} else if (mode == ConnectMode.ABORT_ON_CONFLICT) {
outpoint.fromTx = out.getParentTransaction();
return TransactionInput.ConnectionResult.ALREADY_SPENT;
}
}
connect(out);
return TransactionInput.ConnectionResult.SUCCESS;
}
/** Internal use only: connects this TransactionInput to the given output (updates pointers and spent flags) */
public void connect(TransactionOutput out) {
outpoint.fromTx = out.getParentTransaction();
out.markAsSpent(this);
value = out.getValue();
}
/**
* If this input is connected, check the output is connected back to this input and release it if so, making
* it spendable once again.
*
* @return true if the disconnection took place, false if it was not connected.
*/
public boolean disconnect() {
TransactionOutput connectedOutput;
if (outpoint.fromTx != null) {
// The outpoint is connected using a "standard" wallet, disconnect it.
connectedOutput = outpoint.fromTx.getOutput((int) outpoint.getIndex());
outpoint.fromTx = null;
} else if (outpoint.connectedOutput != null) {
// The outpoint is connected using a UTXO based wallet, disconnect it.
connectedOutput = outpoint.connectedOutput;
outpoint.connectedOutput = null;
} else {
// The outpoint is not connected, do nothing.
return false;
}
if (connectedOutput != null && connectedOutput.getSpentBy() == this) {
// The outpoint was connected to an output, disconnect the output.
connectedOutput.markAsUnspent();
return true;
} else {
return false;
}
}
/**
* @return true if this transaction's sequence number is set (ie it may be a part of a time-locked transaction)
*/
public boolean hasSequence() {
return sequence != NO_SEQUENCE;
}
/**
* Returns whether this input will cause a transaction to opt into the
* <a href="https://github.com/bitcoin/bips/blob/master/bip-0125.mediawiki">full replace-by-fee </a> semantics.
*/
public boolean isOptInFullRBF() {
return sequence < NO_SEQUENCE - 1;
}
/**
* For a connected transaction, runs the script against the connected pubkey and verifies they are correct.
* @throws ScriptException if the script did not verify.
* @throws VerificationException If the outpoint doesn't match the given output.
*/
public void verify() throws VerificationException {
final Transaction fromTx = getOutpoint().fromTx;
long spendingIndex = getOutpoint().getIndex();
checkNotNull(fromTx, "Not connected");
final TransactionOutput output = fromTx.getOutput((int) spendingIndex);
verify(output);
}
/**
* Verifies that this input can spend the given output. Note that this input must be a part of a transaction.
* Also note that the consistency of the outpoint will be checked, even if this input has not been connected.
*
* @param output the output that this input is supposed to spend.
* @throws ScriptException If the script doesn't verify.
* @throws VerificationException If the outpoint doesn't match the given output.
*/
public void verify(TransactionOutput output) throws VerificationException {
if (output.parent != null) {
if (!getOutpoint().getHash().equals(output.getParentTransaction().getHash()))
throw new VerificationException("This input does not refer to the tx containing the output.");
if (getOutpoint().getIndex() != output.getIndex())
throw new VerificationException("This input refers to a different output on the given tx.");
}
Script pubKey = output.getScriptPubKey();
int myIndex = getParentTransaction().getInputs().indexOf(this);
getScriptSig().correctlySpends(getParentTransaction(), myIndex, pubKey);
}
/**
* Returns the connected output, assuming the input was connected with
* {@link TransactionInput#connect(TransactionOutput)} or variants at some point. If it wasn't connected, then
* this method returns null.
*/
@Nullable
public TransactionOutput getConnectedOutput() {
return getOutpoint().getConnectedOutput();
}
/**
* Returns the connected transaction, assuming the input was connected with
* {@link TransactionInput#connect(TransactionOutput)} or variants at some point. If it wasn't connected, then
* this method returns null.
*/
@Nullable
public Transaction getConnectedTransaction() {
return getOutpoint().fromTx;
}
/** Returns a copy of the input detached from its containing transaction, if need be. */
public TransactionInput duplicateDetached() {
return new TransactionInput(params, null, bitcoinSerialize(), 0);
}
/**
* <p>Returns either RuleViolation.NONE if the input is standard, or which rule makes it non-standard if so.
* The "IsStandard" rules control whether the default Bitcoin Core client blocks relay of a tx / refuses to mine it,
* however, non-standard transactions can still be included in blocks and will be accepted as valid if so.</p>
*
* <p>This method simply calls <tt>DefaultRiskAnalysis.isInputStandard(this)</tt>.</p>
*/
public DefaultRiskAnalysis.RuleViolation isStandard() {
return DefaultRiskAnalysis.isInputStandard(this);
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
TransactionInput other = (TransactionInput) o;
return sequence == other.sequence && parent == other.parent
&& outpoint.equals(other.outpoint) && Arrays.equals(scriptBytes, other.scriptBytes);
}
@Override
public int hashCode() {
return Objects.hashCode(sequence, outpoint, Arrays.hashCode(scriptBytes));
}
/**
* Returns a human readable debug string.
*/
@Override
public String toString() {
StringBuilder s = new StringBuilder("TxIn");
try {
if (isCoinBase()) {
s.append(": COINBASE");
} else {
s.append(" for [").append(outpoint).append("]: ").append(getScriptSig());
String flags = Joiner.on(", ").skipNulls().join(
hasSequence() ? "sequence: " + Long.toHexString(sequence) : null,
isOptInFullRBF() ? "opts into full RBF" : null);
if (!flags.isEmpty())
s.append(" (").append(flags).append(')');
}
return s.toString();
} catch (ScriptException e) {
throw new RuntimeException(e);
}
}
}