introduce tx-state-history-helper and diff-based history

app/scripts/controllers/transactions.js

@@ -8,6 +8,7 @@ const TxProviderUtil = require('../lib/tx-utils')
 const PendingTransactionTracker = require('../lib/pending-tx-tracker')
 const createId = require('../lib/random-id')
 const NonceTracker = require('../lib/nonce-tracker')
+const txStateHistoryHelper = require('../lib/tx-state-history-helper')
 
 module.exports = class TransactionController extends EventEmitter {
   constructor (opts) {
@@ -128,19 +129,17 @@ module.exports = class TransactionController extends EventEmitter {
 
   updateTx (txMeta) {
     // create txMeta snapshot for history
-    const txMetaForHistory = clone(txMeta)
-    // dont include previous history in this snapshot
-    delete txMetaForHistory.history
-    // add snapshot to tx history
-    if (!txMeta.history) txMeta.history = []
-    txMeta.history.push(txMetaForHistory)
+    const currentState = txStateHistoryHelper.snapshotFromTxMeta(txMeta)
+    // recover previous tx state obj
+    const previousState = txStateHistoryHelper.replayHistory(txMeta.history)
+    // generate history entry and add to history
+    const entry = txStateHistoryHelper.generateHistoryEntry(previousState, currentState)
+    txMeta.history.push(entry)
 
+    // commit txMeta to state
     const txId = txMeta.id
     const txList = this.getFullTxList()
     const index = txList.findIndex(txData => txData.id === txId)
-    if (!txMeta.history) txMeta.history = []
-    txMeta.history.push(txMetaForHistory)
-
     txList[index] = txMeta
     this._saveTxList(txList)
     this.emit('update')
@@ -148,16 +147,22 @@ module.exports = class TransactionController extends EventEmitter {
 
   // Adds a tx to the txlist
   addTx (txMeta) {
-    const txCount = this.getTxCount()
-    const network = this.getNetwork()
-    const fullTxList = this.getFullTxList()
-    const txHistoryLimit = this.txHistoryLimit
+    // initialize history
+    txMeta.history = []
+    // capture initial snapshot of txMeta for history
+    const snapshot = txStateHistoryHelper.snapshotFromTxMeta(txMeta)
+    txMeta.history.push(snapshot)
 
     // checks if the length of the tx history is
     // longer then desired persistence limit
     // and then if it is removes only confirmed
     // or rejected tx's.
     // not tx's that are pending or unapproved
+    const txCount = this.getTxCount()
+    const network = this.getNetwork()
+    const fullTxList = this.getFullTxList()
+    const txHistoryLimit = this.txHistoryLimit
+
     if (txCount > txHistoryLimit - 1) {
       const index = fullTxList.findIndex((metaTx) => ((metaTx.status === 'confirmed' || metaTx.status === 'rejected') && network === txMeta.metamaskNetworkId))
       fullTxList.splice(index, 1)
@@ -206,7 +211,6 @@ module.exports = class TransactionController extends EventEmitter {
       status: 'unapproved',
       metamaskNetworkId: this.getNetwork(),
       txParams: txParams,
-      history: [],
     }
     // add default tx params
     await this.addTxDefaults(txMeta)

app/scripts/lib/tx-state-history-helper.js

@@ -0,0 +1,37 @@
+const jsonDiffer = require('fast-json-patch')
+const clone = require('clone')
+
+module.exports = {
+  generateHistoryEntry,
+  replayHistory,
+  snapshotFromTxMeta,
+  migrateFromSnapshotsToDiffs,
+}
+
+
+function migrateFromSnapshotsToDiffs(longHistory) {
+  return (
+    longHistory
+    // convert non-initial history entries into diffs
+    .map((entry, index) => {
+      if (index === 0) return entry
+      return generateHistoryEntry(longHistory[index-1], entry)
+    })
+  )
+}
+
+function generateHistoryEntry(previousState, newState) {
+  return jsonDiffer.compare(previousState, newState)
+}
+
+function replayHistory(shortHistory) {
+  return shortHistory.reduce((val, entry) => jsonDiffer.applyPatch(val, entry).newDocument)
+}
+
+function snapshotFromTxMeta(txMeta) {
+  // create txMeta snapshot for history
+  const snapshot = clone(txMeta)
+  // dont include previous history in this snapshot
+  delete snapshot.history
+  return snapshot
+}

package.json

@@ -82,6 +82,7 @@
     "express": "^4.14.0",
     "extension-link-enabler": "^1.0.0",
     "extensionizer": "^1.0.0",
+    "fast-json-patch": "^2.0.4",
     "fast-levenshtein": "^2.0.6",
     "gulp": "github:gulpjs/gulp#4.0",
     "gulp-eslint": "^4.0.0",

test/unit/tx-controller-test.js

@@ -47,7 +47,7 @@ describe('Transaction Controller', function () {
         metamaskNetworkId: currentNetworkId,
         txParams,
       }
-      txController._saveTxList([txMeta])
+      txController.addTx(txMeta)
       stub = sinon.stub(txController, 'addUnapprovedTransaction').returns(Promise.resolve(txMeta))
     })
 
@@ -279,9 +279,12 @@ describe('Transaction Controller', function () {
     it('replaces the tx with the same id', function () {
       txController.addTx({ id: '1', status: 'unapproved', metamaskNetworkId: currentNetworkId, txParams: {} }, noop)
       txController.addTx({ id: '2', status: 'confirmed', metamaskNetworkId: currentNetworkId, txParams: {} }, noop)
-      txController.updateTx({ id: '1', status: 'blah', hash: 'foo', metamaskNetworkId: currentNetworkId, txParams: {} })
-      var result = txController.getTx('1')
-      assert.equal(result.hash, 'foo')
+      const tx1 = txController.getTx('1')
+      tx1.status = 'blah'
+      tx1.hash = 'foo'
+      txController.updateTx(tx1)
+      const savedResult = txController.getTx('1')
+      assert.equal(savedResult.hash, 'foo')
     })
 
     it('updates gas price', function () {
@@ -297,9 +300,9 @@ describe('Transaction Controller', function () {
         },
       }
 
-      const updatedMeta = clone(txMeta)
 
       txController.addTx(txMeta)
+      const updatedMeta = txController.getTx('1')
       updatedMeta.txParams.gasPrice = desiredGasPrice
       txController.updateTx(updatedMeta)
       var result = txController.getTx('1')

test/unit/tx-state-history-helper.js

@@ -0,0 +1,23 @@
+const assert = require('assert')
+const txStateHistoryHelper = require('../../app/scripts/lib/tx-state-history-helper')
+const testVault = require('../data/v17-long-history.json')
+
+
+describe('history-differ', function () {
+  it('migrates history to diffs and can recover original values', function () {
+    testVault.data.TransactionController.transactions.forEach((tx, index) => {
+      const newHistory = txStateHistoryHelper.migrateFromSnapshotsToDiffs(tx.history)
+      newHistory.forEach((newEntry, index) => {
+        if (index === 0) {
+          assert.equal(Array.isArray(newEntry), false, 'initial history item IS NOT a json patch obj')
+        } else {
+          assert.equal(Array.isArray(newEntry), true, 'non-initial history entry IS a json patch obj')
+        }
+        const oldEntry = tx.history[index]
+        const historySubset = newHistory.slice(0, index + 1)
+        const reconstructedValue = txStateHistoryHelper.replayHistory(historySubset)
+        assert.deepEqual(oldEntry, reconstructedValue, 'was able to reconstruct old entry from diffs')
+      })
+    })
+  })
+})