1 files changed, 55 insertions, 12 deletions

diff --git a/app/scripts/lib/tx-gas-utils.js b/app/scripts/lib/tx-gas-utils.js
index 41f67e230..0fa9dd8d4 100644
--- a/app/scripts/lib/tx-gas-utils.js
+++ b/app/scripts/lib/tx-gas-utils.js
@@ -4,6 +4,8 @@ const {
   BnMultiplyByFraction,
   bnToHex,
 } = require('./util')
+const { addHexPrefix, isValidAddress } = require('ethereumjs-util')
+const SIMPLE_GAS_COST = '0x5208' // Hex for 21000, cost of a simple send.
 
 /*
 tx-utils are utility methods for Transaction manager
@@ -11,7 +13,8 @@ its passed ethquery
 and used to do things like calculate gas of a tx.
 */
 
-module.exports = class txProvideUtil {
+module.exports = class TxGasUtil {
+
   constructor (provider) {
     this.query = new EthQuery(provider)
   }
@@ -22,7 +25,11 @@ module.exports = class txProvideUtil {
     try {
       estimatedGasHex = await this.estimateTxGas(txMeta, block.gasLimit)
     } catch (err) {
-      if (err.message.includes('Transaction execution error.')) {
+      const simulationFailed = (
+        err.message.includes('Transaction execution error.') ||
+        err.message.includes('gas required exceeds allowance or always failing transaction')
+      )
+      if (simulationFailed) {
         txMeta.simulationFails = true
         return txMeta
       }
@@ -33,25 +40,41 @@ module.exports = class txProvideUtil {
 
   async estimateTxGas (txMeta, blockGasLimitHex) {
     const txParams = txMeta.txParams
+
     // check if gasLimit is already specified
     txMeta.gasLimitSpecified = Boolean(txParams.gas)
-    // if not, fallback to block gasLimit
-    if (!txMeta.gasLimitSpecified) {
-      const blockGasLimitBN = hexToBn(blockGasLimitHex)
-      const saferGasLimitBN = BnMultiplyByFraction(blockGasLimitBN, 19, 20)
-      txParams.gas = bnToHex(saferGasLimitBN)
+
+    // if it is, use that value
+    if (txMeta.gasLimitSpecified) {
+      return txParams.gas
     }
+
+    // if recipient has no code, gas is 21k max:
+    const recipient = txParams.to
+    const hasRecipient = Boolean(recipient)
+    const code = await this.query.getCode(recipient)
+    if (hasRecipient && (!code || code === '0x')) {
+      txParams.gas = SIMPLE_GAS_COST
+      txMeta.simpleSend = true // Prevents buffer addition
+      return SIMPLE_GAS_COST
+    }
+
+    // if not, fall back to block gasLimit
+    const blockGasLimitBN = hexToBn(blockGasLimitHex)
+    const saferGasLimitBN = BnMultiplyByFraction(blockGasLimitBN, 19, 20)
+    txParams.gas = bnToHex(saferGasLimitBN)
+
     // run tx
     return await this.query.estimateGas(txParams)
   }
 
   setTxGas (txMeta, blockGasLimitHex, estimatedGasHex) {
-    txMeta.estimatedGas = estimatedGasHex
+    txMeta.estimatedGas = addHexPrefix(estimatedGasHex)
     const txParams = txMeta.txParams
 
     // if gasLimit was specified and doesnt OOG,
     // use original specified amount
-    if (txMeta.gasLimitSpecified) {
+    if (txMeta.gasLimitSpecified || txMeta.simpleSend) {
       txMeta.estimatedGas = txParams.gas
       return
     }
@@ -77,8 +100,28 @@ module.exports = class txProvideUtil {
   }
 
   async validateTxParams (txParams) {
-    if (('value' in txParams) && txParams.value.indexOf('-') === 0) {
-      throw new Error(`Invalid transaction value of ${txParams.value} not a positive number.`)
+    this.validateRecipient(txParams)
+    if ('value' in txParams) {
+      const value = txParams.value.toString()
+      if (value.includes('-')) {
+        throw new Error(`Invalid transaction value of ${txParams.value} not a positive number.`)
+      }
+
+      if (value.includes('.')) {
+        throw new Error(`Invalid transaction value of ${txParams.value} number must be in wei`)
+      }
+    }
+  }
+  validateRecipient (txParams) {
+    if (txParams.to === '0x' || txParams.to === null ) {
+      if (txParams.data) {
+        delete txParams.to
+      } else {
+        throw new Error('Invalid recipient address')
+      }
+    } else if ( txParams.to !== undefined && !isValidAddress(txParams.to) ) {
+      throw new Error('Invalid recipient address')
     }
+    return txParams
   }
-}
\ No newline at end of file
+}