snarky-smt
Version:
Sparse Merkle Tree for SnarkyJS
199 lines (198 loc) • 5.67 kB
JavaScript
import { Field } from 'snarkyjs';
import { strToFieldArry } from '../utils';
export { LevelStore };
/**
* Store based on leveldb
*
* @class LevelStore
* @implements {Store<V>}
* @template V
*/
class LevelStore {
/**
* Creates an instance of LevelStore.
* @param {Level<string, any>} db
* @param {Provable<V>} eltTyp
* @param {string} smtName
* @memberof LevelStore
*/
constructor(db, eltTyp, smtName) {
this.db = db;
this.nodesSubLevel = this.db.sublevel(smtName);
this.leavesSubLevel = this.db.sublevel(smtName + '_leaf');
this.operationCache = [];
this.eltTyp = eltTyp;
}
/**
* Clear all prepare operation cache.
*
* @memberof LevelStore
*/
clearPrepareOperationCache() {
this.operationCache = [];
}
/**
* Get the tree root. Error is thrown when the root does not exist.
*
* @return {*} {Promise<Field>}
* @memberof LevelStore
*/
async getRoot() {
const valueStr = await this.nodesSubLevel.get('root');
return Field(valueStr);
}
/**
* Prepare update the root. Use the commit() method to actually submit changes.
*
* @param {Field} root
* @memberof LevelStore
*/
prepareUpdateRoot(root) {
this.operationCache.push({
type: 'put',
sublevel: this.nodesSubLevel,
key: 'root',
value: root.toString(),
});
}
/**
* Get nodes for a key. Error is thrown when a key that does not exist is being accessed.
*
* @param {Field} key
* @return {*} {Promise<Field[]>}
* @memberof LevelStore
*/
async getNodes(key) {
const valueStr = await this.nodesSubLevel.get(key.toString());
return strToFieldArry(valueStr);
}
/**
* Prepare put nodes for a key. Use the commit() method to actually submit changes.
*
* @param {Field} key
* @param {Field[]} value
* @memberof LevelStore
*/
preparePutNodes(key, value) {
this.operationCache.push({
type: 'put',
sublevel: this.nodesSubLevel,
key: key.toString(),
value: value.toString(),
});
}
/**
* Prepare delete nodes for a key. Use the commit() method to actually submit changes.
*
* @param {Field} key
* @memberof LevelStore
*/
prepareDelNodes(key) {
this.operationCache.push({
type: 'del',
sublevel: this.nodesSubLevel,
key: key.toString(),
});
}
/**
* Convert value string to a value of FieldElements type.
*
* @protected
* @param {string} valueStr
* @param {AsFieldElements<V>} eltTyp
* @return {*} {V}
* @memberof LevelStore
*/
strToValue(valueStr, eltTyp) {
let fs = strToFieldArry(valueStr);
return eltTyp.fromFields(fs, eltTyp.toAuxiliary());
}
/**
* Get the value for a key. Error is thrown when a key that does not exist is being accessed.
*
* @param {Field} path
* @return {*} {Promise<V>}
* @memberof LevelStore
*/
async getValue(path) {
const valueStr = await this.leavesSubLevel.get(path.toString());
return this.strToValue(valueStr, this.eltTyp);
}
/**
* Serialize the value of the FieldElements type into a string
*
* @protected
* @param {V} value
* @return {*} {string}
* @memberof LevelStore
*/
valueToStr(value) {
const valueStr = this.eltTyp.toFields(value).toString();
return valueStr;
}
/**
* Prepare put the value for a key. Use the commit() method to actually submit changes.
*
* @param {Field} path
* @param {V} value
* @memberof LevelStore
*/
preparePutValue(path, value) {
const valueStr = this.valueToStr(value);
this.operationCache.push({
type: 'put',
sublevel: this.leavesSubLevel,
key: path.toString(),
value: valueStr,
});
}
/**
* Prepare delete the value for a key. Use the commit() method to actually submit changes.
*
* @param {Field} path
* @memberof LevelStore
*/
prepareDelValue(path) {
this.operationCache.push({
type: 'del',
sublevel: this.leavesSubLevel,
key: path.toString(),
});
}
/**
* Use the commit() method to actually submit all prepare changes.
*
* @return {*} {Promise<void>}
* @memberof LevelStore
*/
async commit() {
if (this.operationCache.length > 0) {
await this.db.batch(this.operationCache);
}
this.clearPrepareOperationCache();
}
/**
* Clear the store.
*
* @return {*} {Promise<void>}
* @memberof LevelStore
*/
async clear() {
await this.nodesSubLevel.clear();
await this.leavesSubLevel.clear();
}
/**
* Get values map, key is Field.toString().
*
* @return {*} {Promise<Map<string, V>>}
* @memberof LevelStore
*/
async getValuesMap() {
let valuesMap = new Map();
for await (const [key, valueStr] of this.leavesSubLevel.iterator()) {
const value = this.strToValue(valueStr, this.eltTyp);
valuesMap.set(key, value);
}
return valuesMap;
}
}