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Merge pull request #31 from braydonf/rbf
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Transaction: Added replace-by-fee (RBF) support
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@matiu
matiu committed Jun 27, 2016
2 parents 6275689 + f1d19b4 commit d36f728
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Showing 3 changed files with 137 additions and 5 deletions.
9 changes: 6 additions & 3 deletions lib/transaction/input/input.js
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Expand Up @@ -11,9 +11,10 @@ var Script = require('../../script');
var Sighash = require('../sighash');
var Output = require('../output');


var DEFAULT_SEQNUMBER = 0xFFFFFFFF;
var DEFAULT_LOCKTIME_SEQNUMBER = 0x00000000;
var MAXINT = 0xffffffff; // Math.pow(2, 32) - 1;
var DEFAULT_RBF_SEQNUMBER = MAXINT - 2;
var DEFAULT_SEQNUMBER = MAXINT;
var DEFAULT_LOCKTIME_SEQNUMBER = MAXINT - 1;

function Input(params) {
if (!(this instanceof Input)) {
Expand All @@ -24,8 +25,10 @@ function Input(params) {
}
}

Input.MAXINT = MAXINT;
Input.DEFAULT_SEQNUMBER = DEFAULT_SEQNUMBER;
Input.DEFAULT_LOCKTIME_SEQNUMBER = DEFAULT_LOCKTIME_SEQNUMBER;
Input.DEFAULT_RBF_SEQNUMBER = DEFAULT_RBF_SEQNUMBER;

Object.defineProperty(Input.prototype, 'script', {
configurable: false,
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31 changes: 30 additions & 1 deletion lib/transaction/transaction.js
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Expand Up @@ -546,7 +546,7 @@ Transaction.prototype.from = function(utxo, pubkeys, threshold) {
return input.prevTxId.toString('hex') === utxo.txId && input.outputIndex === utxo.outputIndex;
});
if (exists) {
return;
return this;
}
if (pubkeys && threshold) {
this._fromMultisigUtxo(utxo, pubkeys, threshold);
Expand Down Expand Up @@ -1197,5 +1197,34 @@ Transaction.prototype.isCoinbase = function() {
return (this.inputs.length === 1 && this.inputs[0].isNull());
};

/**
* Determines if this transaction can be replaced in the mempool with another
* transaction that provides a sufficiently higher fee (RBF).
*/
Transaction.prototype.isRBF = function() {
for (var i = 0; i < this.inputs.length; i++) {
var input = this.inputs[i];
if (input.sequenceNumber < Input.MAXINT - 1) {
return true;
}
}
return false;
};

/**
* Enable this transaction to be replaced in the mempool (RBF) if a transaction
* includes a sufficiently higher fee. It will set the sequenceNumber to
* DEFAULT_RBF_SEQNUMBER for all inputs if the sequence number does not
* already enable RBF.
*/
Transaction.prototype.enableRBF = function() {
for (var i = 0; i < this.inputs.length; i++) {
var input = this.inputs[i];
if (input.sequenceNumber >= Input.MAXINT - 1) {
input.sequenceNumber = Input.DEFAULT_RBF_SEQNUMBER;
}
}
return this;
};

module.exports = Transaction;
102 changes: 101 additions & 1 deletion test/transaction/transaction.js
View file
Expand Up @@ -214,7 +214,7 @@ describe('Transaction', function() {
var simpleUtxoWith1BTC = {
address: fromAddress,
txId: 'a477af6b2667c29670467e4e0728b685ee07b240235771862318e29ddbe58458',
outputIndex: 0,
outputIndex: 1,
script: Script.buildPublicKeyHashOut(fromAddress).toString(),
satoshis: 1e8
};
Expand Down Expand Up @@ -1120,6 +1120,106 @@ describe('Transaction', function() {

});
});
describe('Replace-by-fee', function() {
describe('#enableRBF', function() {
it('only enable inputs not already enabled (0xffffffff)', function() {
var tx = new Transaction()
.from(simpleUtxoWith1BTC)
.from(simpleUtxoWith100000Satoshis)
.to([{address: toAddress, satoshis: 50000}])
.fee(15000)
.change(changeAddress)
.sign(privateKey);
tx.inputs[0].sequenceNumber = 0x00000000;
tx.enableRBF();
tx.inputs[0].sequenceNumber.should.equal(0x00000000);
tx.inputs[1].sequenceNumber.should.equal(0xfffffffd);
});
it('enable for inputs with 0xffffffff and 0xfffffffe', function() {
var tx = new Transaction()
.from(simpleUtxoWith1BTC)
.from(simpleUtxoWith100000Satoshis)
.to([{address: toAddress, satoshis: 50000}])
.fee(15000)
.change(changeAddress)
.sign(privateKey);
tx.inputs[0].sequenceNumber = 0xffffffff;
tx.inputs[1].sequenceNumber = 0xfffffffe;
tx.enableRBF();
tx.inputs[0].sequenceNumber.should.equal(0xfffffffd);
tx.inputs[1].sequenceNumber.should.equal(0xfffffffd);
});
});
describe('#isRBF', function() {
it('enable and determine opt-in', function() {
var tx = new Transaction()
.from(simpleUtxoWith100000Satoshis)
.to([{address: toAddress, satoshis: 50000}])
.fee(15000)
.change(changeAddress)
.enableRBF()
.sign(privateKey);
tx.isRBF().should.equal(true);
});
it('determine opt-out with default sequence number', function() {
var tx = new Transaction()
.from(simpleUtxoWith100000Satoshis)
.to([{address: toAddress, satoshis: 50000}])
.fee(15000)
.change(changeAddress)
.sign(privateKey);
tx.isRBF().should.equal(false);
});
it('determine opt-out with 0xfffffffe', function() {
var tx = new Transaction()
.from(simpleUtxoWith1BTC)
.from(simpleUtxoWith100000Satoshis)
.to([{address: toAddress, satoshis: 50000 + 1e8}])
.fee(15000)
.change(changeAddress)
.sign(privateKey);
tx.inputs[0].sequenceNumber = 0xfffffffe;
tx.inputs[1].sequenceNumber = 0xfffffffe;
tx.isRBF().should.equal(false);
});
it('determine opt-out with 0xffffffff', function() {
var tx = new Transaction()
.from(simpleUtxoWith1BTC)
.from(simpleUtxoWith100000Satoshis)
.to([{address: toAddress, satoshis: 50000 + 1e8}])
.fee(15000)
.change(changeAddress)
.sign(privateKey);
tx.inputs[0].sequenceNumber = 0xffffffff;
tx.inputs[1].sequenceNumber = 0xffffffff;
tx.isRBF().should.equal(false);
});
it('determine opt-in with 0xfffffffd (first input)', function() {
var tx = new Transaction()
.from(simpleUtxoWith1BTC)
.from(simpleUtxoWith100000Satoshis)
.to([{address: toAddress, satoshis: 50000 + 1e8}])
.fee(15000)
.change(changeAddress)
.sign(privateKey);
tx.inputs[0].sequenceNumber = 0xfffffffd;
tx.inputs[1].sequenceNumber = 0xffffffff;
tx.isRBF().should.equal(true);
});
it('determine opt-in with 0xfffffffd (second input)', function() {
var tx = new Transaction()
.from(simpleUtxoWith1BTC)
.from(simpleUtxoWith100000Satoshis)
.to([{address: toAddress, satoshis: 50000 + 1e8}])
.fee(15000)
.change(changeAddress)
.sign(privateKey);
tx.inputs[0].sequenceNumber = 0xffffffff;
tx.inputs[1].sequenceNumber = 0xfffffffd;
tx.isRBF().should.equal(true);
});
});
});
});


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