1 files changed, 132 insertions, 0 deletions
diff --git a/app/scripts/lib/tx-utils.js b/app/scripts/lib/tx-utils.js
new file mode 100644
index 000000000..5116cb93b
--- /dev/null
+++ b/app/scripts/lib/tx-utils.js
@@ -0,0 +1,132 @@
+const async = require('async')
+const EthQuery = require('eth-query')
+const ethUtil = require('ethereumjs-util')
+const Transaction = require('ethereumjs-tx')
+const normalize = require('./sig-util').normalize
+const BN = ethUtil.BN
+
+/*
+tx-utils are utility methods for Transaction manager
+its passed a provider and that is passed to ethquery
+and used to do things like calculate gas of a tx.
+*/
+
+module.exports = class txProviderUtils {
+  constructor (provider) {
+    this.provider = provider
+    this.query = new EthQuery(provider)
+  }
+
+  analyzeGasUsage (txData, cb) {
+    var self = this
+    this.query.getBlockByNumber('latest', true, (err, block) => {
+      if (err) return cb(err)
+      async.waterfall([
+        self.estimateTxGas.bind(self, txData, block.gasLimit),
+        self.setTxGas.bind(self, txData, block.gasLimit),
+      ], cb)
+    })
+  }
+
+  estimateTxGas (txData, blockGasLimitHex, cb) {
+    const txParams = txData.txParams
+    // check if gasLimit is already specified
+    txData.gasLimitSpecified = Boolean(txParams.gas)
+    // if not, fallback to block gasLimit
+    if (!txData.gasLimitSpecified) {
+      txParams.gas = blockGasLimitHex
+    }
+    // run tx, see if it will OOG
+    this.query.estimateGas(txParams, cb)
+  }
+
+  setTxGas (txData, blockGasLimitHex, estimatedGasHex, cb) {
+    txData.estimatedGas = estimatedGasHex
+    const txParams = txData.txParams
+
+    // if gasLimit was specified and doesnt OOG,
+    // use original specified amount
+    if (txData.gasLimitSpecified) {
+      txData.estimatedGas = txParams.gas
+      cb()
+      return
+    }
+    // if gasLimit not originally specified,
+    // try adding an additional gas buffer to our estimation for safety
+    const estimatedGasBn = new BN(ethUtil.stripHexPrefix(txData.estimatedGas), 16)
+    const blockGasLimitBn = new BN(ethUtil.stripHexPrefix(blockGasLimitHex), 16)
+    const estimationWithBuffer = new BN(this.addGasBuffer(estimatedGasBn), 16)
+    // added gas buffer is too high
+    if (estimationWithBuffer.gt(blockGasLimitBn)) {
+      txParams.gas = txData.estimatedGas
+    // added gas buffer is safe
+    } else {
+      const gasWithBufferHex = ethUtil.intToHex(estimationWithBuffer)
+      txParams.gas = gasWithBufferHex
+    }
+    cb()
+    return
+  }
+
+  addGasBuffer (gas) {
+    const gasBuffer = new BN('100000', 10)
+    const bnGas = new BN(ethUtil.stripHexPrefix(gas), 16)
+    const correct = bnGas.add(gasBuffer)
+    return ethUtil.addHexPrefix(correct.toString(16))
+  }
+
+  fillInTxParams (txParams, cb) {
+    let fromAddress = txParams.from
+    let reqs = {}
+
+    if (isUndef(txParams.gas)) reqs.gas = (cb) => this.query.estimateGas(txParams, cb)
+    if (isUndef(txParams.gasPrice)) reqs.gasPrice = (cb) => this.query.gasPrice(cb)
+    if (isUndef(txParams.nonce)) reqs.nonce = (cb) => this.query.getTransactionCount(fromAddress, 'pending', cb)
+
+    async.parallel(reqs, function(err, result) {
+      if (err) return cb(err)
+      // write results to txParams obj
+      Object.assign(txParams, result)
+      cb()
+    })
+  }
+
+  // builds ethTx from txParams object
+  buildEthTxFromParams (txParams, gasMultiplier = 1) {
+    // apply gas multiplyer
+    let gasPrice = new BN(ethUtil.stripHexPrefix(txParams.gasPrice), 16)
+    // multiply and divide by 100 so as to add percision to integer mul
+    gasPrice = gasPrice.mul(new BN(gasMultiplier * 100, 10)).div(new BN(100, 10))
+    txParams.gasPrice = ethUtil.intToHex(gasPrice.toNumber())
+    // normalize values
+    txParams.to = normalize(txParams.to)
+    txParams.from = normalize(txParams.from)
+    txParams.value = normalize(txParams.value)
+    txParams.data = normalize(txParams.data)
+    txParams.gasLimit = normalize(txParams.gasLimit || txParams.gas)
+    txParams.nonce = normalize(txParams.nonce)
+    // build ethTx
+    const ethTx = new Transaction(txParams)
+    return ethTx
+  }
+
+  publishTransaction (rawTx, cb) {
+    this.query.sendRawTransaction(rawTx, cb)
+  }
+
+  validateTxParams (txParams, cb) {
+    if (('value' in txParams) && txParams.value.indexOf('-') === 0) {
+      cb(new Error(`Invalid transaction value of ${txParams.value} not a positive number.`))
+    } else {
+      cb()
+    }
+  }
+
+
+}
+
+// util
+
+function isUndef(value) {
+  return value === undefined
+}