108 lines
3.9 KiB
JavaScript
108 lines
3.9 KiB
JavaScript
"use strict";
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var __importDefault = (this && this.__importDefault) || function (mod) {
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return (mod && mod.__esModule) ? mod : { "default": mod };
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};
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Object.defineProperty(exports, "__esModule", { value: true });
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const simpleHash_1 = __importDefault(require("./simpleHash"));
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const BaseTree_1 = require("./BaseTree");
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class MerkleTree extends BaseTree_1.BaseTree {
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constructor(levels, elements = [], { hashFunction = simpleHash_1.default, zeroElement = 0, } = {}) {
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super();
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this.levels = levels;
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if (elements.length > this.capacity) {
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throw new Error('Tree is full');
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}
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this._hashFn = hashFunction;
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this.zeroElement = zeroElement;
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this._layers = [];
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const leaves = elements.slice();
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this._layers = [leaves];
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this._buildZeros();
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this._buildHashes();
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}
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_buildHashes() {
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for (let layerIndex = 1; layerIndex <= this.levels; layerIndex++) {
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const nodes = this._layers[layerIndex - 1];
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this._layers[layerIndex] = this._processNodes(nodes, layerIndex);
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}
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}
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/**
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* Insert multiple elements into the tree.
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* @param {Array} elements Elements to insert
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*/
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bulkInsert(elements) {
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if (!elements.length) {
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return;
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}
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if (this._layers[0].length + elements.length > this.capacity) {
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throw new Error('Tree is full');
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}
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// First we insert all elements except the last one
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// updating only full subtree hashes (all layers where inserted element has odd index)
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// the last element will update the full path to the root making the tree consistent again
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for (let i = 0; i < elements.length - 1; i++) {
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this._layers[0].push(elements[i]);
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let level = 0;
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let index = this._layers[0].length - 1;
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while (index % 2 === 1) {
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level++;
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index >>= 1;
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this._layers[level][index] = this._hashFn(this._layers[level - 1][index * 2], this._layers[level - 1][index * 2 + 1]);
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}
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}
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this.insert(elements[elements.length - 1]);
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}
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getTreeEdge(edgeIndex) {
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const edgeElement = this._layers[0][edgeIndex];
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if (edgeElement === undefined) {
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throw new Error('Element not found');
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}
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const edgePath = this.path(edgeIndex);
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return { edgePath, edgeElement, edgeIndex, edgeElementsCount: this._layers[0].length };
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}
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/**
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* 🪓
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* @param count
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*/
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getTreeSlices(count = 4) {
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const length = this._layers[0].length;
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let size = Math.ceil(length / count);
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if (size % 2)
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size++;
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const slices = [];
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for (let i = 0; i < length; i += size) {
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const edgeLeft = i;
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const edgeRight = i + size;
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slices.push({ edge: this.getTreeEdge(edgeLeft), elements: this.elements.slice(edgeLeft, edgeRight) });
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}
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return slices;
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}
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/**
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* Serialize entire tree state including intermediate layers into a plain object
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* Deserializing it back will not require to recompute any hashes
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* Elements are not converted to a plain type, this is responsibility of the caller
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*/
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serialize() {
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return {
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levels: this.levels,
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_zeros: this._zeros,
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_layers: this._layers,
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};
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}
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/**
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* Deserialize data into a MerkleTree instance
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* Make sure to provide the same hashFunction as was used in the source tree,
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* otherwise the tree state will be invalid
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*/
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static deserialize(data, hashFunction) {
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const instance = Object.assign(Object.create(this.prototype), data);
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instance._hashFn = hashFunction || simpleHash_1.default;
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instance.zeroElement = instance._zeros[0];
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return instance;
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}
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toString() {
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return JSON.stringify(this.serialize());
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}
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}
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exports.default = MerkleTree;
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