merkle-patricia-tree/dist/baseTrie.js

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.Trie = void 0;
const semaphore_async_await_1 = __importDefault(require("semaphore-async-await"));
const ethereumjs_util_1 = require("ethereumjs-util");
const db_1 = require("./db");
const readStream_1 = require("./readStream");
const nibbles_1 = require("./util/nibbles");
const walkController_1 = require("./util/walkController");
const trieNode_1 = require("./trieNode");
const assert = require('assert');
/**
 * The basic trie interface, use with `import { BaseTrie as Trie } from 'merkle-patricia-tree'`.
 * In Ethereum applications stick with the {@link SecureTrie} overlay.
 * The API for the base and the secure interface are about the same.
 */
class Trie {
    /**
     * test
     * @param db - A [levelup](https://github.com/Level/levelup) instance. By default (if the db is `null` or
     * left undefined) creates an in-memory [memdown](https://github.com/Level/memdown) instance.
     * @param root - A `Buffer` for the root of a previously stored trie
     * @param deleteFromDB - Delete nodes from DB on delete operations (disallows switching to an older state root) (default: `false`)
     */
    constructor(db, root, deleteFromDB = false) {
        this.EMPTY_TRIE_ROOT = ethereumjs_util_1.KECCAK256_RLP;
        this.lock = new semaphore_async_await_1.default(1);
        this.db = db ? new db_1.DB(db) : new db_1.DB();
        this._root = this.EMPTY_TRIE_ROOT;
        this._deleteFromDB = deleteFromDB;
        if (root) {
            this.root = root;
        }
    }
    /**
     * Sets the current root of the `trie`
     */
    set root(value) {
        if (!value) {
            value = this.EMPTY_TRIE_ROOT;
        }
        assert(value.length === 32, 'Invalid root length. Roots are 32 bytes');
        this._root = value;
    }
    /**
     * Gets the current root of the `trie`
     */
    get root() {
        return this._root;
    }
    /**
     * This method is deprecated.
     * Please use {@link Trie.root} instead.
     *
     * @param value
     * @deprecated
     */
    setRoot(value) {
        this.root = value !== null && value !== void 0 ? value : this.EMPTY_TRIE_ROOT;
    }
    /**
     * Checks if a given root exists.
     */
    async checkRoot(root) {
        try {
            const value = await this._lookupNode(root);
            return value !== null;
        }
        catch (error) {
            if (error.message == 'Missing node in DB') {
                return false;
            }
            else {
                throw error;
            }
        }
    }
    /**
     * BaseTrie has no checkpointing so return false
     */
    get isCheckpoint() {
        return false;
    }
    /**
     * Gets a value given a `key`
     * @param key - the key to search for
     * @param throwIfMissing - if true, throws if any nodes are missing. Used for verifying proofs. (default: false)
     * @returns A Promise that resolves to `Buffer` if a value was found or `null` if no value was found.
     */
    async get(key, throwIfMissing = false) {
        const { node, remaining } = await this.findPath(key, throwIfMissing);
        let value = null;
        if (node && remaining.length === 0) {
            value = node.value;
        }
        return value;
    }
    /**
     * Stores a given `value` at the given `key` or do a delete if `value` is empty
     * (delete operations are only executed on DB with `deleteFromDB` set to `true`)
     * @param key
     * @param value
     * @returns A Promise that resolves once value is stored.
     */
    async put(key, value) {
        // If value is empty, delete
        if (!value || value.toString() === '') {
            return await this.del(key);
        }
        await this.lock.wait();
        if (this.root.equals(ethereumjs_util_1.KECCAK256_RLP)) {
            // If no root, initialize this trie
            await this._createInitialNode(key, value);
        }
        else {
            // First try to find the given key or its nearest node
            const { remaining, stack } = await this.findPath(key);
            // then update
            await this._updateNode(key, value, remaining, stack);
        }
        this.lock.signal();
    }
    /**
     * Deletes a value given a `key` from the trie
     * (delete operations are only executed on DB with `deleteFromDB` set to `true`)
     * @param key
     * @returns A Promise that resolves once value is deleted.
     */
    async del(key) {
        await this.lock.wait();
        const { node, stack } = await this.findPath(key);
        if (node) {
            await this._deleteNode(key, stack);
        }
        this.lock.signal();
    }
    /**
     * Tries to find a path to the node for the given key.
     * It returns a `stack` of nodes to the closest node.
     * @param key - the search key
     * @param throwIfMissing - if true, throws if any nodes are missing. Used for verifying proofs. (default: false)
     */
    async findPath(key, throwIfMissing = false) {
        // eslint-disable-next-line no-async-promise-executor
        return new Promise(async (resolve, reject) => {
            const stack = [];
            const targetKey = (0, nibbles_1.bufferToNibbles)(key);
            const onFound = async (nodeRef, node, keyProgress, walkController) => {
                if (node === null) {
                    return reject(new Error('Path not found'));
                }
                const keyRemainder = targetKey.slice((0, nibbles_1.matchingNibbleLength)(keyProgress, targetKey));
                stack.push(node);
                if (node instanceof trieNode_1.BranchNode) {
                    if (keyRemainder.length === 0) {
                        // we exhausted the key without finding a node
                        resolve({ node, remaining: [], stack });
                    }
                    else {
                        const branchIndex = keyRemainder[0];
                        const branchNode = node.getBranch(branchIndex);
                        if (!branchNode) {
                            // there are no more nodes to find and we didn't find the key
                            resolve({ node: null, remaining: keyRemainder, stack });
                        }
                        else {
                            // node found, continuing search
                            // this can be optimized as this calls getBranch again.
                            walkController.onlyBranchIndex(node, keyProgress, branchIndex);
                        }
                    }
                }
                else if (node instanceof trieNode_1.LeafNode) {
                    if ((0, nibbles_1.doKeysMatch)(keyRemainder, node.key)) {
                        // keys match, return node with empty key
                        resolve({ node, remaining: [], stack });
                    }
                    else {
                        // reached leaf but keys dont match
                        resolve({ node: null, remaining: keyRemainder, stack });
                    }
                }
                else if (node instanceof trieNode_1.ExtensionNode) {
                    const matchingLen = (0, nibbles_1.matchingNibbleLength)(keyRemainder, node.key);
                    if (matchingLen !== node.key.length) {
                        // keys don't match, fail
                        resolve({ node: null, remaining: keyRemainder, stack });
                    }
                    else {
                        // keys match, continue search
                        walkController.allChildren(node, keyProgress);
                    }
                }
            };
            // walk trie and process nodes
            try {
                await this.walkTrie(this.root, onFound);
            }
            catch (error) {
                if (error.message == 'Missing node in DB' && !throwIfMissing) {
                    // pass
                }
                else {
                    reject(error);
                }
            }
            // Resolve if _walkTrie finishes without finding any nodes
            resolve({ node: null, remaining: [], stack });
        });
    }
    /**
     * Walks a trie until finished.
     * @param root
     * @param onFound - callback to call when a node is found. This schedules new tasks. If no tasks are available, the Promise resolves.
     * @returns Resolves when finished walking trie.
     */
    async walkTrie(root, onFound) {
        await walkController_1.WalkController.newWalk(onFound, this, root);
    }
    /**
     * @hidden
     * Backwards compatibility
     * @param root -
     * @param onFound -
     */
    async _walkTrie(root, onFound) {
        await this.walkTrie(root, onFound);
    }
    /**
     * Creates the initial node from an empty tree.
     * @private
     */
    async _createInitialNode(key, value) {
        const newNode = new trieNode_1.LeafNode((0, nibbles_1.bufferToNibbles)(key), value);
        this.root = newNode.hash();
        await this.db.put(this.root, newNode.serialize());
    }
    /**
     * Retrieves a node from db by hash.
     */
    async lookupNode(node) {
        if ((0, trieNode_1.isRawNode)(node)) {
            return (0, trieNode_1.decodeRawNode)(node);
        }
        let value = null;
        let foundNode = null;
        value = await this.db.get(node);
        if (value) {
            foundNode = (0, trieNode_1.decodeNode)(value);
        }
        else {
            // Dev note: this error message text is used for error checking in `checkRoot`, `verifyProof`, and `findPath`
            throw new Error('Missing node in DB');
        }
        return foundNode;
    }
    /**
     * @hidden
     * Backwards compatibility
     * @param node The node hash to lookup from the DB
     */
    async _lookupNode(node) {
        return this.lookupNode(node);
    }
    /**
     * Updates a node.
     * @private
     * @param key
     * @param value
     * @param keyRemainder
     * @param stack
     */
    async _updateNode(k, value, keyRemainder, stack) {
        const toSave = [];
        const lastNode = stack.pop();
        if (!lastNode) {
            throw new Error('Stack underflow');
        }
        // add the new nodes
        const key = (0, nibbles_1.bufferToNibbles)(k);
        // Check if the last node is a leaf and the key matches to this
        let matchLeaf = false;
        if (lastNode instanceof trieNode_1.LeafNode) {
            let l = 0;
            for (let i = 0; i < stack.length; i++) {
                const n = stack[i];
                if (n instanceof trieNode_1.BranchNode) {
                    l++;
                }
                else {
                    l += n.key.length;
                }
            }
            if ((0, nibbles_1.matchingNibbleLength)(lastNode.key, key.slice(l)) === lastNode.key.length &&
                keyRemainder.length === 0) {
                matchLeaf = true;
            }
        }
        if (matchLeaf) {
            // just updating a found value
            lastNode.value = value;
            stack.push(lastNode);
        }
        else if (lastNode instanceof trieNode_1.BranchNode) {
            stack.push(lastNode);
            if (keyRemainder.length !== 0) {
                // add an extension to a branch node
                keyRemainder.shift();
                // create a new leaf
                const newLeaf = new trieNode_1.LeafNode(keyRemainder, value);
                stack.push(newLeaf);
            }
            else {
                lastNode.value = value;
            }
        }
        else {
            // create a branch node
            const lastKey = lastNode.key;
            const matchingLength = (0, nibbles_1.matchingNibbleLength)(lastKey, keyRemainder);
            const newBranchNode = new trieNode_1.BranchNode();
            // create a new extension node
            if (matchingLength !== 0) {
                const newKey = lastNode.key.slice(0, matchingLength);
                const newExtNode = new trieNode_1.ExtensionNode(newKey, value);
                stack.push(newExtNode);
                lastKey.splice(0, matchingLength);
                keyRemainder.splice(0, matchingLength);
            }
            stack.push(newBranchNode);
            if (lastKey.length !== 0) {
                const branchKey = lastKey.shift();
                if (lastKey.length !== 0 || lastNode instanceof trieNode_1.LeafNode) {
                    // shrinking extension or leaf
                    lastNode.key = lastKey;
                    const formattedNode = this._formatNode(lastNode, false, toSave);
                    newBranchNode.setBranch(branchKey, formattedNode);
                }
                else {
                    // remove extension or attaching
                    this._formatNode(lastNode, false, toSave, true);
                    newBranchNode.setBranch(branchKey, lastNode.value);
                }
            }
            else {
                newBranchNode.value = lastNode.value;
            }
            if (keyRemainder.length !== 0) {
                keyRemainder.shift();
                // add a leaf node to the new branch node
                const newLeafNode = new trieNode_1.LeafNode(keyRemainder, value);
                stack.push(newLeafNode);
            }
            else {
                newBranchNode.value = value;
            }
        }
        await this._saveStack(key, stack, toSave);
    }
    /**
     * Deletes a node from the trie.
     * @private
     */
    async _deleteNode(k, stack) {
        const processBranchNode = (key, branchKey, branchNode, parentNode, stack) => {
            // branchNode is the node ON the branch node not THE branch node
            if (!parentNode || parentNode instanceof trieNode_1.BranchNode) {
                // branch->?
                if (parentNode) {
                    stack.push(parentNode);
                }
                if (branchNode instanceof trieNode_1.BranchNode) {
                    // create an extension node
                    // branch->extension->branch
                    // @ts-ignore
                    const extensionNode = new trieNode_1.ExtensionNode([branchKey], null);
                    stack.push(extensionNode);
                    key.push(branchKey);
                }
                else {
                    const branchNodeKey = branchNode.key;
                    // branch key is an extension or a leaf
                    // branch->(leaf or extension)
                    branchNodeKey.unshift(branchKey);
                    branchNode.key = branchNodeKey.slice(0);
                    key = key.concat(branchNodeKey);
                }
                stack.push(branchNode);
            }
            else {
                // parent is an extension
                let parentKey = parentNode.key;
                if (branchNode instanceof trieNode_1.BranchNode) {
                    // ext->branch
                    parentKey.push(branchKey);
                    key.push(branchKey);
                    parentNode.key = parentKey;
                    stack.push(parentNode);
                }
                else {
                    const branchNodeKey = branchNode.key;
                    // branch node is an leaf or extension and parent node is an exstention
                    // add two keys together
                    // dont push the parent node
                    branchNodeKey.unshift(branchKey);
                    key = key.concat(branchNodeKey);
                    parentKey = parentKey.concat(branchNodeKey);
                    branchNode.key = parentKey;
                }
                stack.push(branchNode);
            }
            return key;
        };
        let lastNode = stack.pop();
        assert(lastNode);
        let parentNode = stack.pop();
        const opStack = [];
        let key = (0, nibbles_1.bufferToNibbles)(k);
        if (!parentNode) {
            // the root here has to be a leaf.
            this.root = this.EMPTY_TRIE_ROOT;
            return;
        }
        if (lastNode instanceof trieNode_1.BranchNode) {
            lastNode.value = null;
        }
        else {
            // the lastNode has to be a leaf if it's not a branch.
            // And a leaf's parent, if it has one, must be a branch.
            if (!(parentNode instanceof trieNode_1.BranchNode)) {
                throw new Error('Expected branch node');
            }
            const lastNodeKey = lastNode.key;
            key.splice(key.length - lastNodeKey.length);
            // delete the value
            this._formatNode(lastNode, false, opStack, true);
            parentNode.setBranch(key.pop(), null);
            lastNode = parentNode;
            parentNode = stack.pop();
        }
        // nodes on the branch
        // count the number of nodes on the branch
        const branchNodes = lastNode.getChildren();
        // if there is only one branch node left, collapse the branch node
        if (branchNodes.length === 1) {
            // add the one remaing branch node to node above it
            const branchNode = branchNodes[0][1];
            const branchNodeKey = branchNodes[0][0];
            // look up node
            const foundNode = await this._lookupNode(branchNode);
            if (foundNode) {
                key = processBranchNode(key, branchNodeKey, foundNode, parentNode, stack);
                await this._saveStack(key, stack, opStack);
            }
        }
        else {
            // simple removing a leaf and recaluclation the stack
            if (parentNode) {
                stack.push(parentNode);
            }
            stack.push(lastNode);
            await this._saveStack(key, stack, opStack);
        }
    }
    /**
     * Saves a stack of nodes to the database.
     * @private
     * @param key - the key. Should follow the stack
     * @param stack - a stack of nodes to the value given by the key
     * @param opStack - a stack of levelup operations to commit at the end of this funciton
     */
    async _saveStack(key, stack, opStack) {
        let lastRoot;
        // update nodes
        while (stack.length) {
            const node = stack.pop();
            if (node instanceof trieNode_1.LeafNode) {
                key.splice(key.length - node.key.length);
            }
            else if (node instanceof trieNode_1.ExtensionNode) {
                key.splice(key.length - node.key.length);
                if (lastRoot) {
                    node.value = lastRoot;
                }
            }
            else if (node instanceof trieNode_1.BranchNode) {
                if (lastRoot) {
                    const branchKey = key.pop();
                    node.setBranch(branchKey, lastRoot);
                }
            }
            lastRoot = this._formatNode(node, stack.length === 0, opStack);
        }
        if (lastRoot) {
            this.root = lastRoot;
        }
        await this.db.batch(opStack);
    }
    /**
     * Formats node to be saved by `levelup.batch`.
     * @private
     * @param node - the node to format.
     * @param topLevel - if the node is at the top level.
     * @param opStack - the opStack to push the node's data.
     * @param remove - whether to remove the node (only used for CheckpointTrie).
     * @returns The node's hash used as the key or the rawNode.
     */
    _formatNode(node, topLevel, opStack, remove = false) {
        const rlpNode = node.serialize();
        if (rlpNode.length >= 32 || topLevel) {
            // Do not use TrieNode.hash() here otherwise serialize()
            // is applied twice (performance)
            const hashRoot = (0, ethereumjs_util_1.keccak)(rlpNode);
            if (remove) {
                if (this._deleteFromDB) {
                    opStack.push({
                        type: 'del',
                        key: hashRoot,
                    });
                }
            }
            else {
                opStack.push({
                    type: 'put',
                    key: hashRoot,
                    value: rlpNode,
                });
            }
            return hashRoot;
        }
        return node.raw();
    }
    /**
     * The given hash of operations (key additions or deletions) are executed on the trie
     * (delete operations are only executed on DB with `deleteFromDB` set to `true`)
     * @example
     * const ops = [
     *    { type: 'del', key: Buffer.from('father') }
     *  , { type: 'put', key: Buffer.from('name'), value: Buffer.from('Yuri Irsenovich Kim') }
     *  , { type: 'put', key: Buffer.from('dob'), value: Buffer.from('16 February 1941') }
     *  , { type: 'put', key: Buffer.from('spouse'), value: Buffer.from('Kim Young-sook') }
     *  , { type: 'put', key: Buffer.from('occupation'), value: Buffer.from('Clown') }
     * ]
     * await trie.batch(ops)
     * @param ops
     */
    async batch(ops) {
        for (const op of ops) {
            if (op.type === 'put') {
                if (!op.value) {
                    throw new Error('Invalid batch db operation');
                }
                await this.put(op.key, op.value);
            }
            else if (op.type === 'del') {
                await this.del(op.key);
            }
        }
    }
    /**
     * Saves the nodes from a proof into the trie. If no trie is provided a new one wil be instantiated.
     * @param proof
     * @param trie
     */
    static async fromProof(proof, trie) {
        const opStack = proof.map((nodeValue) => {
            return {
                type: 'put',
                key: (0, ethereumjs_util_1.keccak)(nodeValue),
                value: nodeValue,
            };
        });
        if (!trie) {
            trie = new Trie();
            if (opStack[0]) {
                trie.root = opStack[0].key;
            }
        }
        await trie.db.batch(opStack);
        return trie;
    }
    /**
     * prove has been renamed to {@link Trie.createProof}.
     * @deprecated
     * @param trie
     * @param key
     */
    static async prove(trie, key) {
        return this.createProof(trie, key);
    }
    /**
     * Creates a proof from a trie and key that can be verified using {@link Trie.verifyProof}.
     * @param trie
     * @param key
     */
    static async createProof(trie, key) {
        const { stack } = await trie.findPath(key);
        const p = stack.map((stackElem) => {
            return stackElem.serialize();
        });
        return p;
    }
    /**
     * Verifies a proof.
     * @param rootHash
     * @param key
     * @param proof
     * @throws If proof is found to be invalid.
     * @returns The value from the key, or null if valid proof of non-existence.
     */
    static async verifyProof(rootHash, key, proof) {
        let proofTrie = new Trie(null, rootHash);
        try {
            proofTrie = await Trie.fromProof(proof, proofTrie);
        }
        catch (e) {
            throw new Error('Invalid proof nodes given');
        }
        try {
            const value = await proofTrie.get(key, true);
            return value;
        }
        catch (err) {
            if (err.message == 'Missing node in DB') {
                throw new Error('Invalid proof provided');
            }
            else {
                throw err;
            }
        }
    }
    /**
     * The `data` event is given an `Object` that has two properties; the `key` and the `value`. Both should be Buffers.
     * @return Returns a [stream](https://nodejs.org/dist/latest-v12.x/docs/api/stream.html#stream_class_stream_readable) of the contents of the `trie`
     */
    createReadStream() {
        return new readStream_1.TrieReadStream(this);
    }
    /**
     * Creates a new trie backed by the same db.
     */
    copy() {
        const db = this.db.copy();
        return new Trie(db._leveldb, this.root);
    }
    /**
     * Finds all nodes that are stored directly in the db
     * (some nodes are stored raw inside other nodes)
     * called by {@link ScratchReadStream}
     * @private
     */
    async _findDbNodes(onFound) {
        const outerOnFound = async (nodeRef, node, key, walkController) => {
            if ((0, trieNode_1.isRawNode)(nodeRef)) {
                if (node !== null) {
                    walkController.allChildren(node, key);
                }
            }
            else {
                onFound(nodeRef, node, key, walkController);
            }
        };
        await this.walkTrie(this.root, outerOnFound);
    }
    /**
     * Finds all nodes that store k,v values
     * called by {@link TrieReadStream}
     * @private
     */
    async _findValueNodes(onFound) {
        const outerOnFound = async (nodeRef, node, key, walkController) => {
            let fullKey = key;
            if (node instanceof trieNode_1.LeafNode) {
                fullKey = key.concat(node.key);
                // found leaf node!
                onFound(nodeRef, node, fullKey, walkController);
            }
            else if (node instanceof trieNode_1.BranchNode && node.value) {
                // found branch with value
                onFound(nodeRef, node, fullKey, walkController);
            }
            else {
                // keep looking for value nodes
                if (node !== null) {
                    walkController.allChildren(node, key);
                }
            }
        };
        await this.walkTrie(this.root, outerOnFound);
    }
}
exports.Trie = Trie;
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