add Bitcash support

Reviewers: arik

Subscribers: ben

Differential Revision: https://phabricator.bitgo.com/D6102

Author: bencxr

package.json

@@ -1,6 +1,6 @@
 {
   "name": "bitgo",
-  "version": "3.4.10",
+  "version": "3.4.11",
   "description": "BitGo Javascript SDK",
   "main": "./src/index.js",
   "keywords": [

src/v2/baseCoin.js

@@ -57,6 +57,7 @@ BaseCoin.prototype.initializeCoin = function(coin) {
     coinInstances = {
       btc: require('./coins/btc'),
       tbtc: require('./coins/tbtc'),
+      bch: require('./coins/bch'),
       ltc: require('./coins/ltc'),
       tltc: require('./coins/tltc'),
       eth: require('./coins/eth'),

src/v2/coins/bch.js

@@ -0,0 +1,76 @@
+var Btc = require('./btc');
+var bitcoin = require('bitcoinjs-lib');
+var _ = require('lodash');
+
+var Bch = function() {
+  // this function is called externally from BaseCoin
+  // replace the BaseCoin prototype with the local override prototype, which inherits from BaseCoin
+  // effectively, move the BaseCoin prototype one level away
+  this.__proto__ = Bch.prototype;
+  this.network = {
+    messagePrefix: '\x19Bitcash Signed Message:\n',
+    bip32: {
+      public: 0x0488b21e,
+      private: 0x0488ade4
+    },
+    pubKeyHash: 0x30,
+    scriptHash: 0x32,
+    wif: 0xb0,
+    dustThreshold: 0, // https://github.com/litecoin-project/litecoin/blob/v0.8.7.2/src/main.cpp#L360-L365
+    dustSoftThreshold: 100000, // https://github.com/litecoin-project/litecoin/blob/v0.8.7.2/src/main.h#L53
+    feePerKb: 100000 // https://github.com/litecoin-project/litecoin/blob/v0.8.7.2/src/main.cpp#L56
+  };
+  this.altScriptHash = bitcoin.networks.litecoin.scriptHash;
+  // do not support alt destinations in prod
+  this.supportAltScriptDestination = false;
+};
+
+Bch.prototype.__proto__ = Btc.prototype;
+
+Bch.prototype.getChain = function() {
+  return 'bch';
+};
+Bch.prototype.getFamily = function() {
+  return 'bch';
+};
+
+/**
+ * Canonicalize a Litecoin address for a specific scriptHash version
+ * @param address
+ * @param scriptHashVersion 1 or 2, where 1 is the old version and 2 is the new version
+ * @returns {*} address string
+ */
+Bch.prototype.canonicalAddress = function(address, scriptHashVersion = 2) {
+  if (!this.isValidAddress(address, true)) {
+    throw new Error('invalid address');
+  }
+  const addressDetails = bitcoin.address.fromBase58Check(address);
+  if (addressDetails.version === this.network.pubKeyHash) {
+    // the pub keys never changed
+    return address;
+  }
+
+  if ([1, 2].indexOf(scriptHashVersion) === -1) {
+    throw new Error('scriptHashVersion needs to be either 1 or 2');
+  }
+  const scriptHashMap = {
+    // altScriptHash is the old one
+    1: this.altScriptHash,
+    // by default we're using the new one
+    2: this.network.scriptHash
+  };
+  const newScriptHash = scriptHashMap[scriptHashVersion];
+  return bitcoin.address.toBase58Check(addressDetails.hash, newScriptHash);
+};
+
+Bch.prototype.getRecoveryBlockchainApiBaseUrl = function() {
+  return 'https://ltc.blockr.io/api/v1';
+};
+
+Bch.prototype.calculateRecoveryAddress = function(scriptHashScript) {
+  const bitgoAddress = bitcoin.address.fromOutputScript(scriptHashScript, this.network);
+  const blockrAddress = this.canonicalAddress(bitgoAddress, 1);
+  return blockrAddress;
+};
+
+module.exports = Bch;