1 files changed, 186 insertions, 0 deletions
diff --git a/app/scripts/controllers/transactions/nonce-tracker.js b/app/scripts/controllers/transactions/nonce-tracker.js
new file mode 100644
index 000000000..f8cdc5523
--- /dev/null
+++ b/app/scripts/controllers/transactions/nonce-tracker.js
@@ -0,0 +1,186 @@
+const EthQuery = require('ethjs-query')
+const assert = require('assert')
+const Mutex = require('await-semaphore').Mutex
+/**
+  @param opts {Object}
+    @param {Object} opts.provider a ethereum provider
+    @param {Function} opts.getPendingTransactions a function that returns an array of txMeta
+    whosee status is `submitted`
+    @param {Function} opts.getConfirmedTransactions a function that returns an array of txMeta
+    whose status is `confirmed`
+  @class
+*/
+class NonceTracker {
+
+  constructor ({ provider, getPendingTransactions, getConfirmedTransactions }) {
+    this.provider = provider
+    this.ethQuery = new EthQuery(provider)
+    this.getPendingTransactions = getPendingTransactions
+    this.getConfirmedTransactions = getConfirmedTransactions
+    this.lockMap = {}
+  }
+
+  /**
+    @returns {Promise<Object>} with the key releaseLock (the gloabl mutex)
+  */
+  async getGlobalLock () {
+    const globalMutex = this._lookupMutex('global')
+    // await global mutex free
+    const releaseLock = await globalMutex.acquire()
+    return { releaseLock }
+  }
+
+  /**
+   * @typedef NonceDetails
+   * @property {number} highestLocallyConfirmed - A hex string of the highest nonce on a confirmed transaction.
+   * @property {number} nextNetworkNonce - The next nonce suggested by the eth_getTransactionCount method.
+   * @property {number} highetSuggested - The maximum between the other two, the number returned.
+   */
+
+  /**
+  this will return an object with the `nextNonce` `nonceDetails` of type NonceDetails, and the releaseLock
+  Note: releaseLock must be called after adding a signed tx to pending transactions (or discarding).
+
+  @param address {string} the hex string for the address whose nonce we are calculating
+  @returns {Promise<NonceDetails>}
+  */
+  async getNonceLock (address) {
+    // await global mutex free
+    await this._globalMutexFree()
+    // await lock free, then take lock
+    const releaseLock = await this._takeMutex(address)
+    // evaluate multiple nextNonce strategies
+    const nonceDetails = {}
+    const networkNonceResult = await this._getNetworkNextNonce(address)
+    const highestLocallyConfirmed = this._getHighestLocallyConfirmed(address)
+    const nextNetworkNonce = networkNonceResult.nonce
+    const highestSuggested = Math.max(nextNetworkNonce, highestLocallyConfirmed)
+
+    const pendingTxs = this.getPendingTransactions(address)
+    const localNonceResult = this._getHighestContinuousFrom(pendingTxs, highestSuggested) || 0
+
+    nonceDetails.params = {
+      highestLocallyConfirmed,
+      highestSuggested,
+      nextNetworkNonce,
+    }
+    nonceDetails.local = localNonceResult
+    nonceDetails.network = networkNonceResult
+
+    const nextNonce = Math.max(networkNonceResult.nonce, localNonceResult.nonce)
+    assert(Number.isInteger(nextNonce), `nonce-tracker - nextNonce is not an integer - got: (${typeof nextNonce}) "${nextNonce}"`)
+
+    // return nonce and release cb
+    return { nextNonce, nonceDetails, releaseLock }
+  }
+
+  async _getCurrentBlock () {
+    const blockTracker = this._getBlockTracker()
+    const currentBlock = blockTracker.getCurrentBlock()
+    if (currentBlock) return currentBlock
+    return await new Promise((reject, resolve) => {
+      blockTracker.once('latest', resolve)
+    })
+  }
+
+  async _globalMutexFree () {
+    const globalMutex = this._lookupMutex('global')
+    const release = await globalMutex.acquire()
+    release()
+  }
+
+  async _takeMutex (lockId) {
+    const mutex = this._lookupMutex(lockId)
+    const releaseLock = await mutex.acquire()
+    return releaseLock
+  }
+
+  _lookupMutex (lockId) {
+    let mutex = this.lockMap[lockId]
+    if (!mutex) {
+      mutex = new Mutex()
+      this.lockMap[lockId] = mutex
+    }
+    return mutex
+  }
+
+  async _getNetworkNextNonce (address) {
+    // calculate next nonce
+    // we need to make sure our base count
+    // and pending count are from the same block
+    const currentBlock = await this._getCurrentBlock()
+    const blockNumber = currentBlock.blockNumber
+    const baseCountBN = await this.ethQuery.getTransactionCount(address, blockNumber || 'latest')
+    const baseCount = baseCountBN.toNumber()
+    assert(Number.isInteger(baseCount), `nonce-tracker - baseCount is not an integer - got: (${typeof baseCount}) "${baseCount}"`)
+    const nonceDetails = { blockNumber, baseCount }
+    return { name: 'network', nonce: baseCount, details: nonceDetails }
+  }
+
+  _getHighestLocallyConfirmed (address) {
+    const confirmedTransactions = this.getConfirmedTransactions(address)
+    const highest = this._getHighestNonce(confirmedTransactions)
+    return Number.isInteger(highest) ? highest + 1 : 0
+  }
+
+  _reduceTxListToUniqueNonces (txList) {
+    const reducedTxList = txList.reduce((reducedList, txMeta, index) => {
+      if (!index) return [txMeta]
+      const nonceMatches = txList.filter((txData) => {
+        return txMeta.txParams.nonce === txData.txParams.nonce
+      })
+      if (nonceMatches.length > 1) return reducedList
+      reducedList.push(txMeta)
+      return reducedList
+    }, [])
+    return reducedTxList
+  }
+
+  _getHighestNonce (txList) {
+    const nonces = txList.map((txMeta) => {
+      const nonce = txMeta.txParams.nonce
+      assert(typeof nonce, 'string', 'nonces should be hex strings')
+      return parseInt(nonce, 16)
+    })
+    const highestNonce = Math.max.apply(null, nonces)
+    return highestNonce
+  }
+
+  /**
+    @typedef {object} highestContinuousFrom
+    @property {string} - name the name for how the nonce was calculated based on the data used
+    @property {number} - nonce the next suggested nonce
+    @property {object} - details the provided starting nonce that was used (for debugging)
+  */
+  /**
+    @param txList {array} - list of txMeta's
+    @param startPoint {number} - the highest known locally confirmed nonce
+    @returns {highestContinuousFrom}
+  */
+  _getHighestContinuousFrom (txList, startPoint) {
+    const nonces = txList.map((txMeta) => {
+      const nonce = txMeta.txParams.nonce
+      assert(typeof nonce, 'string', 'nonces should be hex strings')
+      return parseInt(nonce, 16)
+    })
+
+    let highest = startPoint
+    while (nonces.includes(highest)) {
+      highest++
+    }
+
+    return { name: 'local', nonce: highest, details: { startPoint, highest } }
+  }
+
+  // this is a hotfix for the fact that the blockTracker will
+  // change when the network changes
+
+  /**
+    @returns {Object} the current blockTracker
+  */
+  _getBlockTracker () {
+    return this.provider._blockTracker
+  }
+}
+
+module.exports = NonceTracker