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) try { // 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 } } catch (err) { // release lock if we encounter an error releaseLock() throw err } } 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 releaseLock = await globalMutex.acquire() releaseLock() } 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 } _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