feat: add method to restore sml store from json (#213)

Author: antouhou

lib/deterministicmnlist/SimplifiedMNList.js

@@ -2,6 +2,9 @@ const BufferWriter = require('../encoding/bufferwriter');
 const Hash = require('../crypto/hash');
 const { getMerkleTree, getMerkleRoot } = require('../util/merkletree');
 const SimplifiedMNListDiff = require('./SimplifiedMNListDiff');
+const QuorumEntry = require('./QuorumEntry');
+const SimplifiedMNListEntry = require('./SimplifiedMNListEntry');
+const PartialMerkleTree = require('../block/PartialMerkleTree');
 const constants = require('../constants');
 const Networks = require('../networks');
 const Transaction = require('../transaction');
@@ -449,6 +452,30 @@ SimplifiedMNList.prototype.toSimplifiedMNListDiff = function toSimplifiedMNListD
   }, network);
 };
 
+/**
+ * Recreates SML from json
+ * @param {Object} smlJson
+ */
+SimplifiedMNList.fromJSON = function fromJSON(smlJson) {
+  const sml = new SimplifiedMNList();
+  sml.baseBlockHash = smlJson.baseBlockHash;
+  sml.blockHash = smlJson.blockHash;
+  sml.merkleRootMNList = smlJson.merkleRootMNList;
+  sml.lastDiffMerkleRootMNList = smlJson.lastDiffMerkleRootMNList;
+  sml.lastDiffMerkleRootQuorums = smlJson.lastDiffMerkleRootQuorums;
+  sml.quorumsActive = smlJson.quorumsActive;
+  sml.cbTx = new Transaction(smlJson.cbTx);
+  sml.cbTxMerkleTree = new PartialMerkleTree();
+  sml.cbTxMerkleTree.totalTransactions = smlJson.cbTxMerkleTree.totalTransactions;
+  sml.cbTxMerkleTree.merkleHashes = smlJson.cbTxMerkleTree.merkleHashes;
+  sml.cbTxMerkleTree.merkleFlags = smlJson.cbTxMerkleTree.merkleFlags;
+  sml.mnList = smlJson.mnList.map(mnRecord => new SimplifiedMNListEntry(mnRecord));
+  sml.quorumList = smlJson.quorumList.map(quorumEntry => new QuorumEntry(quorumEntry));
+  sml.validMNs = smlJson.validMNs.map(mnRecord => new SimplifiedMNListEntry(mnRecord));
+
+  return sml;
+};
+
 /**
  * Deterministically selects all members of the quorum which
  * has started it's DKG session with the block of this MNList

lib/deterministicmnlist/SimplifiedMNListDiff.js

@@ -164,7 +164,9 @@ SimplifiedMNListDiff.fromObject = function fromObject(obj, network) {
   simplifiedMNListDiff.cbTx = new Transaction(obj.cbTx);
   // Copy array of strings
   simplifiedMNListDiff.deletedMNs = obj.deletedMNs.slice();
-  simplifiedMNListDiff.mnList = obj.mnList.map(SMLEntry => new SimplifiedMNListEntry(SMLEntry, validNetwork));
+  simplifiedMNListDiff.mnList = obj.mnList.map(
+    SMLEntry => new SimplifiedMNListEntry(SMLEntry, validNetwork),
+  );
   simplifiedMNListDiff.deletedQuorums = obj.deletedQuorums.slice();
   simplifiedMNListDiff.newQuorums = obj.newQuorums.map(quorumEntry => new QuorumEntry(quorumEntry));
   simplifiedMNListDiff.merkleRootMNList = obj.merkleRootMNList;
@@ -185,6 +187,23 @@ SimplifiedMNListDiff.fromObject = function fromObject(obj, network) {
   return simplifiedMNListDiff;
 };
 
+/**
+ * This method constructs the diff from the JSON produced by JSON.sringify.
+ * PLEASE DON'T PASS RESULT OF .toObject() to this method!
+ * @param {Object} diffJSON
+ * @return {SimplifiedMNListDiff}
+ */
+SimplifiedMNListDiff.fromJSON = function fromJSON(diffJSON) {
+  const cbTxMerkleTree = new PartialMerkleTree();
+  cbTxMerkleTree.totalTransactions = diffJSON.cbTxMerkleTree.totalTransactions;
+  cbTxMerkleTree.merkleHashes = diffJSON.cbTxMerkleTree.merkleHashes;
+  cbTxMerkleTree.merkleFlags = diffJSON.cbTxMerkleTree.merkleFlags;
+
+  return SimplifiedMNListDiff.fromObject({
+    ...diffJSON, cbTxMerkleTree,
+  }, Networks.get(diffJSON.network.name));
+};
+
 SimplifiedMNListDiff.prototype.toObject = function toObject() {
   const obj = {};
   obj.baseBlockHash = this.baseBlockHash;

lib/deterministicmnlist/SimplifiedMNListStore.js

@@ -68,7 +68,12 @@ SimplifiedMNListStore.prototype.addDiff = function addDiff(diff) {
   }
 
   if (this.diffStore.length >= this.maxDiffs - 1) {
+    let oldestCoinbase = this.diffStore[0].diff.cbTx;
     this.baseSimplifiedMNList.applyDiff(this.diffStore[0].diff);
+    if (typeof oldestCoinbase === 'string') {
+      oldestCoinbase = new Transaction(oldestCoinbase);
+    }
+    this.baseHeight = oldestCoinbase.extraPayload.height;
     this.diffStore.shift();
   }
 
@@ -127,7 +132,7 @@ SimplifiedMNListStore.prototype.getSMLbyHeight = function getSMLbyHeight(height)
   const diffs = this.getSMLDiffbyHeightRange(this.baseHeight, height);
 
   if (diffs.length === 0) {
-    throw new Error('unable to construct SML at this height');
+    throw new Error(`Unable to reconstruct SML at height ${height}`);
   }
   return this.createListFromBaseAndDiffs(diffs);
 };
@@ -156,4 +161,22 @@ SimplifiedMNListStore.prototype.createListFromBaseAndDiffs = function createList
   return createdList;
 };
 
+/**
+ * Restores store that was recreated from JSON.stringify
+ * @param smlStoreJSON
+ * @return {SimplifiedMNListStore}
+ */
+SimplifiedMNListStore.fromJSON = function fromJSON(smlStoreJSON) {
+  const baseDiff = SimplifiedMNList
+    .fromJSON(smlStoreJSON.baseSimplifiedMNList).toSimplifiedMNListDiff();
+  // Getting jsons of all other diffs
+  const diffsFromFile = smlStoreJSON.diffStore
+    .map(diff => SimplifiedMNListDiff.fromJSON(diff.diff));
+  // Concatenating all diffs into an array
+  const totalDiffsFromFile = [baseDiff, ...diffsFromFile];
+  const smlStore = new SimplifiedMNListStore(totalDiffsFromFile, smlStoreJSON.options);
+
+  return smlStore;
+};
+
 module.exports = SimplifiedMNListStore;

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@dashevo/dashcore-lib",
-  "version": "0.19.17",
+  "version": "0.19.18",
   "description": "A pure and powerful JavaScript Dash library.",
   "author": "Dash Core Group, Inc. <dev@dash.org>",
   "main": "index.js",

package.json

@@ -3,16 +3,18 @@ const constants = require('../../lib/constants');
 const SimplifiedMNListStore = require('../../lib/deterministicmnlist/SimplifiedMNListStore');
 const SMNListFixture = require('../fixtures/mnList');
 const Transaction = require('../../lib/transaction');
+const getSMLStoreJSONFixture = require('../fixtures/getSMLStoreJSON');
+const sml4848Json = require('../fixtures/smlstore4848_4864.json');
 
 let smlDiffArray;
-
-
+let sml4848;
 
 describe('SimplifiedMNListStore', function () {
   this.timeout(5000);
 
   beforeEach(()=>{
     smlDiffArray = SMNListFixture.getChainlockDiffArray();
+    sml4848 = SimplifiedMNListStore.fromJSON(sml4848Json);
   });
 
   describe('constructor', function () {
@@ -101,7 +103,36 @@ describe('SimplifiedMNListStore', function () {
       const height = 11111;
       expect(function () {
         smlStore.getSMLbyHeight(height);
-      }).to.throw('unable to construct SML at this height');
+      }).to.throw('Unable to reconstruct SML at height 11111');
+    });
+  });
+  describe('.fromJSON', function () {
+    it('should restore an SML store from JSON', function () {
+      const smlStoreJSON = getSMLStoreJSONFixture();
+      const smlStore = SimplifiedMNListStore.fromJSON(getSMLStoreJSONFixture());
+      const restoredSmlStoreJson = JSON.parse(JSON.stringify(smlStore));
+
+      expect(restoredSmlStoreJson).to.be.deep.equal(smlStoreJSON);
+    });
+  });
+  describe('.addDiff', function () {
+    it('should update baseHeight if the base diff was updated', function () {
+      const smlStore = SimplifiedMNListStore.fromJSON(getSMLStoreJSONFixture());
+
+      expect(smlStore.baseHeight).to.be.equal(4838);
+
+      const diffAtHeight4854 = sml4848.diffStore[4].diff;
+      const diffAtHeight4855 = sml4848.diffStore[5].diff;
+
+      smlStore.addDiff(diffAtHeight4854);
+
+      expect(smlStore.baseHeight).to.be.equal(4839);
+      expect(smlStore.tipHeight).to.be.equal(smlStore.baseHeight + 15);
+
+      smlStore.addDiff(diffAtHeight4855);
+
+      expect(smlStore.baseHeight).to.be.equal(4840);
+      expect(smlStore.tipHeight).to.be.equal(smlStore.baseHeight + 15);
     });
   });
 });

test/deterministicmnlist/SimplifiedMNListStore.js

@@ -0,0 +1,5 @@
+const json = require('./smlstore4765_4853.json');
+
+module.exports = function () {
+    return JSON.parse(JSON.stringify(json));
+}