bitcoinjs-lib/src/transaction_builder.js
2015-11-26 12:07:32 +11:00

444 lines
13 KiB
JavaScript

var baddress = require('./address')
var bcrypto = require('./crypto')
var bscript = require('./script')
var bufferEquals = require('buffer-equals')
var networks = require('./networks')
var ops = require('./opcodes')
var ECPair = require('./ecpair')
var ECSignature = require('./ecsignature')
var Transaction = require('./transaction')
// re-orders signatures to match pubKeys, fills undefined otherwise
function fixMSSignatures (transaction, vin, pubKeys, signatures, prevOutScript, hashType, skipPubKey) {
// maintain a local copy of unmatched signatures
var unmatched = signatures.slice()
var cache = {}
return pubKeys.map(function (pubKey) {
// skip optionally provided pubKey
if (skipPubKey && bufferEquals(skipPubKey, pubKey)) return undefined
var matched
var keyPair2 = ECPair.fromPublicKeyBuffer(pubKey)
// check for a matching signature
unmatched.some(function (signature, i) {
// skip if undefined || OP_0
if (!signature) return false
var signatureHash = cache[hashType] = cache[hashType] || transaction.hashForSignature(vin, prevOutScript, hashType)
if (!keyPair2.verify(signatureHash, signature)) return false
// remove matched signature from unmatched
unmatched[i] = undefined
matched = signature
return true
})
return matched || undefined
})
}
function extractInput (transaction, txIn, vin) {
var redeemScript
var scriptSig = txIn.script
var scriptSigChunks = bscript.decompile(scriptSig)
var prevOutScript
var prevOutType = bscript.classifyInput(scriptSig, true)
var scriptType
// Re-classify if scriptHash
if (prevOutType === 'scripthash') {
redeemScript = scriptSigChunks.slice(-1)[0]
prevOutScript = bscript.scriptHashOutput(bcrypto.hash160(redeemScript))
scriptSig = bscript.compile(scriptSigChunks.slice(0, -1))
scriptSigChunks = scriptSigChunks.slice(0, -1)
scriptType = bscript.classifyInput(scriptSig, true)
} else {
scriptType = prevOutType
}
// pre-empt redeemScript decompilation
var redeemScriptChunks
if (redeemScript) {
redeemScriptChunks = bscript.decompile(redeemScript)
}
// Extract hashType, pubKeys and signatures
var hashType, parsed, pubKeys, signatures
switch (scriptType) {
case 'pubkeyhash':
parsed = ECSignature.parseScriptSignature(scriptSigChunks[0])
hashType = parsed.hashType
pubKeys = scriptSigChunks.slice(1)
signatures = [parsed.signature]
prevOutScript = bscript.pubKeyHashOutput(bcrypto.hash160(pubKeys[0]))
break
case 'pubkey':
parsed = ECSignature.parseScriptSignature(scriptSigChunks[0])
hashType = parsed.hashType
signatures = [parsed.signature]
if (redeemScript) {
pubKeys = redeemScriptChunks.slice(0, 1)
}
break
case 'multisig':
signatures = scriptSigChunks.slice(1).map(function (chunk) {
if (chunk === ops.OP_0) return undefined
var parsed = ECSignature.parseScriptSignature(chunk)
hashType = parsed.hashType
return parsed.signature
})
if (redeemScript) {
pubKeys = redeemScriptChunks.slice(1, -2)
if (pubKeys.length !== signatures.length) {
signatures = fixMSSignatures(transaction, vin, pubKeys, signatures, redeemScript, hashType, redeemScript)
}
}
break
}
return {
hashType: hashType,
prevOutScript: prevOutScript,
prevOutType: prevOutType,
pubKeys: pubKeys,
redeemScript: redeemScript,
scriptType: scriptType,
signatures: signatures
}
}
function TransactionBuilder (network) {
this.prevTxMap = {}
this.prevOutScripts = {}
this.prevOutTypes = {}
this.network = network || networks.bitcoin
this.inputs = []
this.tx = new Transaction()
}
TransactionBuilder.fromTransaction = function (transaction, network) {
var txb = new TransactionBuilder(network)
// Copy other transaction fields
txb.tx.version = transaction.version
txb.tx.locktime = transaction.locktime
// Extract/add inputs
transaction.ins.forEach(function (txIn) {
txb.addInput(txIn.hash, txIn.index, txIn.sequence)
})
// Extract/add outputs
transaction.outs.forEach(function (txOut) {
txb.addOutput(txOut.script, txOut.value)
})
// Extract/add signatures
txb.inputs = transaction.ins.map(function (txIn, vin) {
// TODO: verify whether extractInput is sane with coinbase scripts
if (Transaction.isCoinbaseHash(txIn.hash)) {
throw new Error('coinbase inputs not supported')
}
// Ignore empty scripts
if (txIn.script.length === 0) return {}
return extractInput(transaction, txIn, vin)
})
return txb
}
TransactionBuilder.prototype.addInput = function (txHash, vout, sequence, prevOutScript) {
// is it a hex string?
if (typeof txHash === 'string') {
// transaction hashs's are displayed in reverse order, un-reverse it
txHash = [].reverse.call(new Buffer(txHash, 'hex'))
// is it a Transaction object?
} else if (txHash instanceof Transaction) {
prevOutScript = txHash.outs[vout].script
txHash = txHash.getHash()
}
var input = {}
if (prevOutScript) {
var prevOutScriptChunks = bscript.decompile(prevOutScript)
var prevOutType = bscript.classifyOutput(prevOutScriptChunks)
// if we can, extract pubKey information
switch (prevOutType) {
case 'multisig':
input.pubKeys = prevOutScriptChunks.slice(1, -2)
input.signatures = input.pubKeys.map(function () { return undefined })
break
case 'pubkey':
input.pubKeys = prevOutScriptChunks.slice(0, 1)
input.signatures = [undefined]
break
}
if (prevOutType !== 'scripthash') {
input.scriptType = prevOutType
}
input.prevOutScript = prevOutScript
input.prevOutType = prevOutType
}
var valid = this.inputs.every(function (input2) {
if (input2.hashType === undefined) return true
return input2.hashType & Transaction.SIGHASH_ANYONECANPAY
})
if (!valid) throw new Error('No, this would invalidate signatures')
var prevOut = txHash.toString('hex') + ':' + vout
if (this.prevTxMap[prevOut]) throw new Error('Transaction is already an input')
var vin = this.tx.addInput(txHash, vout, sequence)
this.inputs[vin] = input
this.prevTxMap[prevOut] = vin
return vin
}
TransactionBuilder.prototype.addOutput = function (scriptPubKey, value) {
var nOutputs = this.tx.outs.length
var valid = this.inputs.every(function (input, index) {
if (input.hashType === undefined) return true
var hashTypeMod = input.hashType & 0x1f
return (hashTypeMod === Transaction.SIGHASH_NONE) ||
(hashTypeMod === Transaction.SIGHASH_SINGLE && index < nOutputs)
})
if (!valid) throw new Error('No, this would invalidate signatures')
// Attempt to get a script if it's a base58 address string
if (typeof scriptPubKey === 'string') {
scriptPubKey = baddress.toOutputScript(scriptPubKey, this.network)
}
return this.tx.addOutput(scriptPubKey, value)
}
TransactionBuilder.prototype.build = function () {
return this.__build(false)
}
TransactionBuilder.prototype.buildIncomplete = function () {
return this.__build(true)
}
var canBuildTypes = {
'multisig': true,
'pubkey': true,
'pubkeyhash': true
}
TransactionBuilder.prototype.__build = function (allowIncomplete) {
if (!allowIncomplete) {
if (!this.tx.ins.length) throw new Error('Transaction has no inputs')
if (!this.tx.outs.length) throw new Error('Transaction has no outputs')
}
var tx = this.tx.clone()
// Create script signatures from inputs
this.inputs.forEach(function (input, index) {
var scriptType = input.scriptType
var scriptSig
if (!allowIncomplete) {
if (!scriptType) throw new Error('Transaction is not complete')
if (!canBuildTypes[scriptType]) throw new Error(scriptType + ' not supported')
// XXX: only relevant to types that need signatures
if (!input.signatures) throw new Error('Transaction is missing signatures')
}
if (input.signatures) {
switch (scriptType) {
case 'pubkeyhash':
var pkhSignature = input.signatures[0].toScriptSignature(input.hashType)
scriptSig = bscript.pubKeyHashInput(pkhSignature, input.pubKeys[0])
break
case 'multisig':
var msSignatures = input.signatures.map(function (signature) {
return signature && signature.toScriptSignature(input.hashType)
})
// fill in blanks with OP_0
if (allowIncomplete) {
for (var i = 0; i < msSignatures.length; ++i) {
msSignatures[i] = msSignatures[i] || ops.OP_0
}
// remove blank signatures
} else {
msSignatures = msSignatures.filter(function (x) { return x })
}
var redeemScript = allowIncomplete ? undefined : input.redeemScript
scriptSig = bscript.multisigInput(msSignatures, redeemScript)
break
case 'pubkey':
var pkSignature = input.signatures[0].toScriptSignature(input.hashType)
scriptSig = bscript.pubKeyInput(pkSignature)
break
}
}
// did we build a scriptSig?
if (scriptSig) {
// wrap as scriptHash if necessary
if (input.prevOutType === 'scripthash') {
scriptSig = bscript.scriptHashInput(scriptSig, input.redeemScript)
}
tx.setInputScript(index, scriptSig)
}
})
return tx
}
TransactionBuilder.prototype.sign = function (index, keyPair, redeemScript, hashType) {
if (keyPair.network !== this.network) throw new Error('Inconsistent network')
if (!this.inputs[index]) throw new Error('No input at index: ' + index)
hashType = hashType || Transaction.SIGHASH_ALL
var input = this.inputs[index]
var canSign = input.hashType &&
input.prevOutScript &&
input.prevOutType &&
input.pubKeys &&
input.scriptType &&
input.signatures &&
input.signatures.length === input.pubKeys.length
var kpPubKey = keyPair.getPublicKeyBuffer()
// are we ready to sign?
if (canSign) {
// if redeemScript was provided, enforce consistency
if (redeemScript) {
if (!bufferEquals(input.redeemScript, redeemScript)) throw new Error('Inconsistent redeemScript')
}
if (input.hashType !== hashType) throw new Error('Inconsistent hashType')
// no? prepare
} else {
// must be pay-to-scriptHash?
if (redeemScript) {
// if we have a prevOutScript, enforce scriptHash equality to the redeemScript
if (input.prevOutScript) {
if (input.prevOutType !== 'scripthash') throw new Error('PrevOutScript must be P2SH')
var scriptHash = bscript.decompile(input.prevOutScript)[1]
if (!bufferEquals(scriptHash, bcrypto.hash160(redeemScript))) throw new Error('RedeemScript does not match ' + scriptHash.toString('hex'))
}
var scriptType = bscript.classifyOutput(redeemScript)
var redeemScriptChunks = bscript.decompile(redeemScript)
var pubKeys
switch (scriptType) {
case 'multisig':
pubKeys = redeemScriptChunks.slice(1, -2)
break
case 'pubkeyhash':
var pkh1 = redeemScriptChunks[2]
var pkh2 = bcrypto.hash160(keyPair.getPublicKeyBuffer())
if (!bufferEquals(pkh1, pkh2)) throw new Error('privateKey cannot sign for this input')
pubKeys = [kpPubKey]
break
case 'pubkey':
pubKeys = redeemScriptChunks.slice(0, 1)
break
default:
throw new Error('RedeemScript not supported (' + scriptType + ')')
}
// if we don't have a prevOutScript, generate a P2SH script
if (!input.prevOutScript) {
input.prevOutScript = bscript.scriptHashOutput(bcrypto.hash160(redeemScript))
input.prevOutType = 'scripthash'
}
input.pubKeys = pubKeys
input.redeemScript = redeemScript
input.scriptType = scriptType
input.signatures = pubKeys.map(function () { return undefined })
} else {
// pay-to-scriptHash is not possible without a redeemScript
if (input.prevOutType === 'scripthash') throw new Error('PrevOutScript is P2SH, missing redeemScript')
// if we don't have a scriptType, assume pubKeyHash otherwise
if (!input.scriptType) {
input.prevOutScript = bscript.pubKeyHashOutput(bcrypto.hash160(keyPair.getPublicKeyBuffer()))
input.prevOutType = 'pubkeyhash'
input.pubKeys = [kpPubKey]
input.scriptType = input.prevOutType
input.signatures = [undefined]
} else {
// throw if we can't sign with it
if (!input.pubKeys || !input.signatures) throw new Error(input.scriptType + ' not supported')
}
}
input.hashType = hashType
}
// ready to sign?
var signatureScript = input.redeemScript || input.prevOutScript
var signatureHash = this.tx.hashForSignature(index, signatureScript, hashType)
// enforce in order signing of public keys
var valid = input.pubKeys.some(function (pubKey, i) {
if (!bufferEquals(kpPubKey, pubKey)) return false
if (input.signatures[i]) throw new Error('Signature already exists')
var signature = keyPair.sign(signatureHash)
input.signatures[i] = signature
return true
})
if (!valid) throw new Error('Key pair cannot sign for this input')
}
module.exports = TransactionBuilder