fix(Eth): higher precision arithmetic for sweep amounts

blockchain · Aug 31, 2017 · b8db591 · b8db591
1 parent c982cea
commit b8db591
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Showing 3 changed files with 23 additions and 4 deletions.
diff --git a/src/eth/eth-tx-builder.js b/src/eth/eth-tx-builder.js
@@ -1,7 +1,7 @@
 const EthereumTx = require('ethereumjs-tx');
 const util = require('ethereumjs-util');
 const API = require('../api');
-const { toWei, fromWei } = require('../helpers');
+const { toWei, fromWei, toBigNumber, bnMax, bnToBuffer } = require('../helpers');
 
 const MAINNET = 1;
 
@@ -34,13 +34,13 @@ class EthTxBuilder {
   }
 
   setValue (amount) {
-    this._tx.value = parseInt(toWei(amount, 'ether'));
+    this._tx.value = bnToBuffer(toWei(toBigNumber(amount), 'ether'));
     this.update();
     return this;
   }
 
   setGasPrice (gasPrice) {
-    this._tx.gasPrice = parseInt(toWei(gasPrice, 'gwei'));
+    this._tx.gasPrice = bnToBuffer(toWei(toBigNumber(gasPrice), 'gwei'));
     this.update();
     return this;
   }
@@ -54,7 +54,7 @@ class EthTxBuilder {
   setSweep () {
     this.setValue(0);
     let balance = this._account.wei;
-    let amount = Math.max(balance.sub(this._tx.getUpfrontCost()), 0);
+    let amount = bnMax(balance.sub(this._tx.getUpfrontCost()), 0);
     this.setValue(fromWei(amount, 'ether'));
     return this;
   }

diff --git a/src/helpers.js b/src/helpers.js
@@ -606,6 +606,16 @@ Helpers.toBigNumber = function (x) {
   return Helpers.isBigNumber(x) ? x : new BigNumber((x || 0).toString());
 };
 
+Helpers.bnMax = function (a, b) {
+  return BigNumber.max(a, b);
+};
+
+Helpers.bnToBuffer = function (bn) {
+  let hex = bn.toString(16);
+  if (hex.length % 2 !== 0) hex = '0' + hex;
+  return Buffer.from(hex, 'hex');
+};
+
 Helpers.isEtherAddress = function (address) {
   return (
     ethUtil.isValidChecksumAddress(address) ||

diff --git a/tests/eth/eth-tx-builder.spec.js b/tests/eth/eth-tx-builder.spec.js
@@ -1,6 +1,7 @@
 /* eslint-disable semi */
 const EthTxBuilder = require('../../src/eth/eth-tx-builder')
 const EthAccount = require('../../src/eth/eth-account')
+const util = require('ethereumjs-util');
 
 describe('EthTxBuilder', () => {
   const wallet = {
@@ -80,6 +81,14 @@ describe('EthTxBuilder', () => {
         expect(payment.amount).toEqual(0.099559)
         expect(payment.fee).toEqual(0.000441)
       })
+
+      it('should sweep with a very large value', () => {
+        account.setData({ balance: '19991027158563527', nonce: 3 })
+        payment.setSweep()
+        expect(new util.BN(payment._tx.value).toString()).toEqual('19550027158563527')
+        expect(payment.amount).toEqual(0.019550027158563528)
+        expect(payment.fee).toEqual(0.000441)
+      })
     })
 
     describe('.sign()', () => {