1 files changed, 146 insertions, 0 deletions
diff --git a/app/scripts/lib/eth-store.js b/app/scripts/lib/eth-store.js
new file mode 100644
index 000000000..7e2caf884
--- /dev/null
+++ b/app/scripts/lib/eth-store.js
@@ -0,0 +1,146 @@
+/* Ethereum Store
+ *
+ * This module is responsible for tracking any number of accounts
+ * and caching their current balances & transaction counts.
+ *
+ * It also tracks transaction hashes, and checks their inclusion status
+ * on each new block.
+ */
+
+const EventEmitter = require('events').EventEmitter
+const inherits = require('util').inherits
+const async = require('async')
+const clone = require('clone')
+const EthQuery = require('eth-query')
+
+module.exports = EthereumStore
+
+
+inherits(EthereumStore, EventEmitter)
+function EthereumStore(engine) {
+  const self = this
+  EventEmitter.call(self)
+  self._currentState = {
+    accounts: {},
+    transactions: {},
+  }
+  self._query = new EthQuery(engine)
+
+  engine.on('block', self._updateForBlock.bind(self))
+}
+
+//
+// public
+//
+
+EthereumStore.prototype.getState = function () {
+  const self = this
+  return clone(self._currentState)
+}
+
+EthereumStore.prototype.addAccount = function (address) {
+  const self = this
+  self._currentState.accounts[address] = {}
+  self._didUpdate()
+  if (!self.currentBlockNumber) return
+  self._updateAccount(address, () => {
+    self._didUpdate()
+  })
+}
+
+EthereumStore.prototype.removeAccount = function (address) {
+  const self = this
+  delete self._currentState.accounts[address]
+  self._didUpdate()
+}
+
+EthereumStore.prototype.addTransaction = function (txHash) {
+  const self = this
+  self._currentState.transactions[txHash] = {}
+  self._didUpdate()
+  if (!self.currentBlockNumber) return
+  self._updateTransaction(self.currentBlockNumber, txHash, noop)
+}
+
+EthereumStore.prototype.removeTransaction = function (address) {
+  const self = this
+  delete self._currentState.transactions[address]
+  self._didUpdate()
+}
+
+
+//
+// private
+//
+
+EthereumStore.prototype._didUpdate = function () {
+  const self = this
+  var state = self.getState()
+  self.emit('update', state)
+}
+
+EthereumStore.prototype._updateForBlock = function (block) {
+  const self = this
+  var blockNumber = '0x' + block.number.toString('hex')
+  self.currentBlockNumber = blockNumber
+  async.parallel([
+    self._updateAccounts.bind(self),
+    self._updateTransactions.bind(self, blockNumber),
+  ], function (err) {
+    if (err) return console.error(err)
+    self.emit('block', self.getState())
+    self._didUpdate()
+  })
+}
+
+EthereumStore.prototype._updateAccounts = function (cb) {
+  var accountsState = this._currentState.accounts
+  var addresses = Object.keys(accountsState)
+  async.each(addresses, this._updateAccount.bind(this), cb)
+}
+
+EthereumStore.prototype._updateAccount = function (address, cb) {
+  var accountsState = this._currentState.accounts
+  this.getAccount(address, function (err, result) {
+    if (err) return cb(err)
+    result.address = address
+    // only populate if the entry is still present
+    if (accountsState[address]) {
+      accountsState[address] = result
+    }
+    cb(null, result)
+  })
+}
+
+EthereumStore.prototype.getAccount = function (address, cb) {
+  const query = this._query
+  async.parallel({
+    balance: query.getBalance.bind(query, address),
+    nonce: query.getTransactionCount.bind(query, address),
+    code: query.getCode.bind(query, address),
+  }, cb)
+}
+
+EthereumStore.prototype._updateTransactions = function (block, cb) {
+  const self = this
+  var transactionsState = self._currentState.transactions
+  var txHashes = Object.keys(transactionsState)
+  async.each(txHashes, self._updateTransaction.bind(self, block), cb)
+}
+
+EthereumStore.prototype._updateTransaction = function (block, txHash, cb) {
+  const self = this
+  // would use the block here to determine how many confirmations the tx has
+  var transactionsState = self._currentState.transactions
+  self._query.getTransaction(txHash, function (err, result) {
+    if (err) return cb(err)
+    // only populate if the entry is still present
+    if (transactionsState[txHash]) {
+      transactionsState[txHash] = result
+      self._didUpdate()
+    }
+    cb(null, result)
+  })
+}
+
+function noop() {}