TxBuilder: Initial commit and tests

src/transaction_builder.js

@@ -0,0 +1,159 @@
+var assert = require('assert')
+var scripts = require('./scripts')
+
+var ECKey = require('./eckey')
+var Transaction = require('./transaction')
+var Script = require('./script')
+
+function TransactionBuilder() {
+  this.prevOutMap = {}
+  this.prevOutScripts = {}
+  this.prevOutTypes = {}
+
+  this.signatures = []
+  this.tx = new Transaction()
+}
+
+TransactionBuilder.prototype.addInput = function(prevTx, index, prevOutScript) {
+  var prevOutHash
+
+  if (typeof prevTx === 'string') {
+    prevOutHash = new Buffer(prevTx, 'hex')
+
+    // TxId hex is big-endian, we want little-endian hash
+    Array.prototype.reverse.call(prevOutHash)
+
+  } else if (prevTx instanceof Transaction) {
+    assert(prevOutScript === undefined, 'Unnecessary Script provided')
+
+    prevOutHash = prevTx.getHash()
+    prevOutScript = prevTx.outs[index].script
+
+  } else {
+    prevOutHash = prevTx
+
+  }
+
+  var prevOutType
+  if (prevOutScript !== undefined) {
+    prevOutType = scripts.classifyOutput(prevOutScript)
+
+    assert.notEqual(prevOutType, 'nonstandard', 'PrevOutScript not supported (nonstandard)')
+  }
+
+  assert(this.signatures.every(function(input) {
+    return input.hashType & Transaction.SIGHASH_ANYONECANPAY
+  }), 'No, this would invalidate signatures')
+
+  var prevOut = prevOutHash.toString('hex') + ':' + index
+  assert(!(prevOut in this.prevOutMap), 'Transaction is already an input')
+
+  var vout = this.tx.addInput(prevOutHash, index)
+  this.prevOutMap[prevOut] = true
+  this.prevOutScripts[vout] = prevOutScript
+  this.prevOutTypes[vout] = prevOutType
+
+  return vout
+}
+
+TransactionBuilder.prototype.addOutput = function(scriptPubKey, value) {
+  assert(this.signatures.every(function(signature) {
+    return (signature.hashType & 0x1f) === Transaction.SIGHASH_SINGLE
+  }), 'No, this would invalidate signatures')
+
+  return this.tx.addOutput(scriptPubKey, value)
+}
+
+TransactionBuilder.prototype.sign = function(index, privKey, redeemScript, hashType) {
+  assert(this.tx.ins.length >= index, 'No input at index: ' + index)
+  hashType = hashType || Transaction.SIGHASH_ALL
+
+  var prevOutScript = this.prevOutScripts[index]
+  var prevOutType = this.prevOutTypes[index]
+
+  var scriptType, hash
+  if (redeemScript) {
+    prevOutScript = prevOutScript || scripts.scriptHashOutput(redeemScript.getHash())
+    prevOutType = prevOutType || 'scripthash'
+
+    assert.equal(prevOutType, 'scripthash', 'PrevOutScript must be P2SH')
+
+    scriptType = scripts.classifyOutput(redeemScript)
+
+    assert.notEqual(scriptType, 'scripthash', 'RedeemScript can\'t be P2SH')
+    assert.notEqual(scriptType, 'nonstandard', 'RedeemScript not supported (nonstandard)')
+
+    hash = this.tx.hashForSignature(index, redeemScript, hashType)
+
+  } else {
+    prevOutScript = prevOutScript || privKey.pub.getAddress().toOutputScript()
+    scriptType = prevOutType || 'pubkeyhash'
+
+    assert.notEqual(scriptType, 'scripthash', 'PrevOutScript requires redeemScript')
+
+    hash = this.tx.hashForSignature(index, prevOutScript, hashType)
+  }
+
+  var signature = privKey.sign(hash)
+
+  if (!(index in this.signatures)) {
+    this.signatures[index] = {
+      hashType: hashType,
+      pubKeys: [],
+      redeemScript: redeemScript,
+      scriptType: scriptType,
+      signatures: []
+    }
+  }
+
+  var input = this.signatures[index]
+  input.pubKeys.push(privKey.pub)
+  input.signatures.push(signature)
+
+  assert.equal(input.hashType, hashType, 'Inconsistent hashType')
+  assert.deepEqual(input.redeemScript, redeemScript, 'Inconsistent redeemScript')
+}
+
+TransactionBuilder.prototype.build = function(allowIncomplete) {
+  if (!allowIncomplete) {
+    assert(this.tx.ins.length > 0, 'Transaction has no inputs')
+    assert(this.tx.outs.length > 0, 'Transaction has no outputs')
+    assert.equal(this.signatures.length, this.tx.ins.length, 'Transaction is missing signatures')
+  }
+
+  var tx = this.tx.clone()
+
+  this.signatures.forEach(function(input, index) {
+    var scriptSig
+
+    if (input.scriptType === 'pubkeyhash') {
+      var signature = input.signatures[0].toScriptSignature(input.hashType)
+      var publicKey = input.pubKeys[0]
+      scriptSig = scripts.pubKeyHashInput(signature, publicKey)
+
+    } else if (input.scriptType === 'multisig') {
+      var redeemScript = allowIncomplete ? undefined : input.redeemScript
+      var signatures = input.signatures.map(function(signature) {
+        return signature.toScriptSignature(input.hashType)
+      })
+      scriptSig = scripts.multisigInput(signatures, redeemScript)
+
+    } else if (input.scriptType === 'pubkey') {
+      var signature = input.signatures[0]
+      scriptSig = scripts.pubKeyInput(signature)
+
+    } else {
+      assert(false, input.scriptType + ' not supported')
+    }
+
+    if (input.redeemScript) {
+      scriptSig = scripts.scriptHashInput(scriptSig, input.redeemScript)
+    }
+
+    tx.setInputScript(index, scriptSig)
+  })
+
+  return tx
+}
+
+module.exports = TransactionBuilder