exonum-client-cis/lib/blockchain/merkle-patricia.js

Light Client for Exonum CIS Blockchain

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.MapProofError = exports.MapProof = void 0;

var _possibleConstructorReturn2 = _interopRequireDefault(require("@babel/runtime/helpers/possibleConstructorReturn"));

var _getPrototypeOf2 = _interopRequireDefault(require("@babel/runtime/helpers/getPrototypeOf"));

var _inherits2 = _interopRequireDefault(require("@babel/runtime/helpers/inherits"));

var _wrapNativeSuper2 = _interopRequireDefault(require("@babel/runtime/helpers/wrapNativeSuper"));

var _toConsumableArray2 = _interopRequireDefault(require("@babel/runtime/helpers/toConsumableArray"));

var _classCallCheck2 = _interopRequireDefault(require("@babel/runtime/helpers/classCallCheck"));

var _binarySearch = _interopRequireDefault(require("binary-search"));

var _crypto = require("../crypto");

var _hexadecimal = require("../types/hexadecimal");

var _constants = require("./constants");

var _ProofPath = _interopRequireDefault(require("./ProofPath"));

var _types = require("../types");

/**
 * Proof of existence and/or absence of certain elements from a Merkelized
 * map index.
 */
var MapProof =
/**
 * Creates a new instance of a proof.
 *
 * @param {Object} json
 *   JSON object containing (untrusted) proof
 * @param {{serialize: (any) => Array<number>}} keyType
 *   Type of keys used in the underlying Merkelized map. Usually, `PublicKey`
 *   or `Hash`. The keys must be serializable.
 * @param {{ serialize: (any) => Array<number>}} valueType
 *   Type of values used in the underlying Merkelized map. Usually, it should
 *   be a type created with the `newType` function. The type must be serializable.
 * @throws {MapProofError}
 *   if the proof is malformed
 */
function MapProof(json, keyType, valueType) {
  (0, _classCallCheck2["default"])(this, MapProof);

  if (!valueType) {
    throw new TypeError('Invalid value type');
  }

  if (typeof valueType.encode === 'function' && typeof valueType.serialize !== 'function') {
    valueType.serialize = function (data, _buff, _offset) {
      return this.encode(data).finish();
    };
  } else if (typeof valueType.serialize !== 'function') {
    throw new TypeError('No `hash` or `serialize` method in the value type');
  }

  this.valueType = valueType;
  this.proof = parseProof(json.proof);
  this.entries = parseEntries(json.entries, keyType, valueType);

  if (!keyType || typeof keyType.serialize !== 'function') {
    throw new TypeError('No `serialize` method in the key type');
  }

  this.keyType = keyType;
  precheckProof.call(this);
  var completeProof = this.proof.concat(this.entries).sort(function (_ref, _ref2) {
    var pathA = _ref.path;
    var pathB = _ref2.path;
    return pathA.compare(pathB);
  }); // This check is required as duplicate paths can be introduced by entries
  // (further, it's generally possible that two different entry keys lead
  //  to the same `ProofPath`).

  for (var i = 1; i < completeProof.length; i++) {
    var _ref3 = [completeProof[i - 1], completeProof[i]],
        pathA = _ref3[0].path,
        pathB = _ref3[1].path;

    if (pathA.compare(pathB) === 0) {
      throw new MapProofError('duplicatePath', pathA);
    }
  }

  var rootHash = (0, _types.hexadecimalToUint8Array)(collect(completeProof.filter(function (_ref4) {
    var hash = _ref4.hash;
    return !!hash;
  })));
  this.merkleRoot = (0, _crypto.hash)([_constants.MAP_PREFIX].concat((0, _toConsumableArray2["default"])(rootHash)));
  this.missingKeys = new Set(this.entries.filter(function (e) {
    return e.missing !== undefined;
  }).map(function (_ref5) {
    var missing = _ref5.missing;
    return missing;
  }));
  this.entries = new Map(this.entries.filter(function (e) {
    return e.key !== undefined;
  }).map(function (_ref6) {
    var key = _ref6.key,
        value = _ref6.value;
    return [key, value];
  }));
};

exports.MapProof = MapProof;

function parseProof(proof) {
  if (!Array.isArray(proof)) {
    throw new MapProofError('malformedProof');
  }

  var validEntries = proof.every(function (_ref7) {
    var path = _ref7.path,
        hash = _ref7.hash;
    return /^[01]{1,256}$/.test(path) && /^[0-9a-f]{64}$/i.test(hash);
  });

  if (!validEntries) {
    throw new MapProofError('malformedProof');
  }

  return proof.map(function (_ref8) {
    var path = _ref8.path,
        hash = _ref8.hash;
    return {
      path: new _ProofPath["default"](path),
      hash: hash
    };
  });
}

function parseEntries(entries, keyType, valueType) {
  function createPath(data) {
    var keyBytes = typeof keyType.hash === 'function' ? keyType.hash(data) : (0, _crypto.hash)(keyType.serialize(data, [], 0));
    var bytes = (0, _types.hexadecimalToUint8Array)(keyBytes);
    return new _ProofPath["default"](new Uint8Array(bytes));
  }

  if (!Array.isArray(entries)) {
    throw new MapProofError('malformedEntries');
  }

  return entries.map(function (_ref9) {
    var missing = _ref9.missing,
        key = _ref9.key,
        value = _ref9.value;

    if (missing === undefined && (key === undefined || value === undefined)) {
      throw new MapProofError('unknownEntryType');
    }

    if (missing !== undefined && (key !== undefined || value !== undefined)) {
      throw new MapProofError('ambiguousEntryType');
    }

    if (missing !== undefined) {
      return {
        missing: missing,
        path: createPath(missing)
      };
    }

    return {
      key: key,
      value: value,
      path: createPath(key),
      hash: (0, _crypto.hash)([_constants.BLOB_PREFIX].concat((0, _toConsumableArray2["default"])(valueType.serialize(value, [], 0))))
    };
  });
}
/**
 * @this {MapProof}
 */


function precheckProof() {
  var _this = this;

  // Check that entries in proof are in increasing order
  for (var i = 1; i < this.proof.length; i++) {
    var _ref10 = [this.proof[i - 1], this.proof[i]],
        prevPath = _ref10[0].path,
        path = _ref10[1].path;

    switch (prevPath.compare(path)) {
      case -1:
        if (path.startsWith(prevPath)) {
          throw new MapProofError('embeddedPaths', prevPath, path);
        }

        break;

      case 0:
        throw new MapProofError('duplicatePath', path);

      case 1:
        throw new MapProofError('invalidOrdering', prevPath, path);
    }
  } // Check that no entry has a prefix among the paths in the proof entries.
  // In order to do this, it suffices to locate the closest smaller path
  // in the proof entries and check only it.


  this.entries.forEach(function (_ref11) {
    var keyPath = _ref11.path;
    var index = (0, _binarySearch["default"])(_this.proof, keyPath, function (_ref12, needle) {
      var path = _ref12.path;
      return path.compare(needle);
    });

    if (index >= 0) {
      throw new MapProofError('duplicatePath', keyPath);
    }

    var insertionIndex = -index - 1;

    if (insertionIndex > 0) {
      var _prevPath = _this.proof[insertionIndex - 1].path;

      if (keyPath.startsWith(_prevPath)) {
        throw new MapProofError('embeddedPaths', _prevPath, keyPath);
      }
    }
  });
}

function serializeBranchNode(leftHash, rightHash, leftPath, rightPath) {
  var buffer = [_constants.MAP_BRANCH_PREFIX];

  _hexadecimal.Hash.serialize(leftHash, buffer, buffer.length);

  _hexadecimal.Hash.serialize(rightHash, buffer, buffer.length);

  leftPath.serialize(buffer);
  rightPath.serialize(buffer);
  return buffer;
}

function serializeIsolatedNode(path, hash) {
  // `1, ...path.key, 0` is the old `ProofPath` serialization for terminal paths.
  var buffer = [_constants.MAP_BRANCH_PREFIX, 1].concat((0, _toConsumableArray2["default"])(path.key), [0]);

  _hexadecimal.Hash.serialize(hash, buffer, buffer.length);

  return buffer;
}

function collect(entries) {
  function hashIsolatedNode(_ref13) {
    var path = _ref13.path,
        valueHash = _ref13.hash;
    var buffer = serializeIsolatedNode(path, valueHash);
    return (0, _crypto.hash)(buffer);
  }

  function hashBranch(left, right) {
    var buffer = serializeBranchNode(left.hash, right.hash, left.path, right.path);
    return (0, _crypto.hash)(buffer);
  }

  function fold(contour, lastPrefix) {
    var lastEntry = contour.pop();
    var penultimateEntry = contour.pop();
    contour.push({
      path: lastPrefix,
      hash: hashBranch(penultimateEntry, lastEntry)
    });
    return contour.length > 1 ? lastPrefix.commonPrefix(contour[contour.length - 2].path) : null;
  }

  switch (entries.length) {
    case 0:
      return '0000000000000000000000000000000000000000000000000000000000000000';

    case 1:
      if (!entries[0].path.isTerminal()) {
        throw new MapProofError('nonTerminalNode', entries[0].path);
      }

      return hashIsolatedNode(entries[0]);

    default:
      var contour = []; // invariant: equal to the common prefix of the 2 last nodes in the contour

      var lastPrefix = entries[0].path.commonPrefix(entries[1].path);
      contour.push(entries[0], entries[1]);

      for (var i = 2; i < entries.length; i++) {
        var entry = entries[i];
        var newPrefix = entry.path.commonPrefix(contour[contour.length - 1].path);

        while (contour.length > 1 && newPrefix.bitLength < lastPrefix.bitLength) {
          var foldedPrefix = fold(contour, lastPrefix);

          if (foldedPrefix) {
            lastPrefix = foldedPrefix;
          }
        }

        contour.push(entry);
        lastPrefix = newPrefix;
      }

      while (contour.length > 1) {
        lastPrefix = fold(contour, lastPrefix);
      }

      return contour[0].hash;
  }
}
/**
 * Error indicating a malformed `MapProof`.
 */


var MapProofError =
/*#__PURE__*/
function (_Error) {
  (0, _inherits2["default"])(MapProofError, _Error);

  function MapProofError(type) {
    var _this2;

    (0, _classCallCheck2["default"])(this, MapProofError);

    switch (type) {
      case 'malformedProof':
        _this2 = (0, _possibleConstructorReturn2["default"])(this, (0, _getPrototypeOf2["default"])(MapProofError).call(this, 'malformed `proof` part of the proof'));
        break;

      case 'malformedEntries':
      case 'unknownEntryType':
      case 'ambiguousEntryType':
        _this2 = (0, _possibleConstructorReturn2["default"])(this, (0, _getPrototypeOf2["default"])(MapProofError).call(this, 'malformed `entries` part of the proof'));
        break;

      case 'embeddedPaths':
        _this2 = (0, _possibleConstructorReturn2["default"])(this, (0, _getPrototypeOf2["default"])(MapProofError).call(this, "embedded paths in proof: ".concat(arguments.length <= 1 ? undefined : arguments[1], " is a prefix of ").concat(arguments.length <= 2 ? undefined : arguments[2])));
        break;

      case 'duplicatePath':
        _this2 = (0, _possibleConstructorReturn2["default"])(this, (0, _getPrototypeOf2["default"])(MapProofError).call(this, "duplicate ".concat(arguments.length <= 1 ? undefined : arguments[1], " in proof")));
        break;

      case 'invalidOrdering':
        _this2 = (0, _possibleConstructorReturn2["default"])(this, (0, _getPrototypeOf2["default"])(MapProofError).call(this, 'invalid path ordering'));
        break;

      case 'nonTerminalNode':
        _this2 = (0, _possibleConstructorReturn2["default"])(this, (0, _getPrototypeOf2["default"])(MapProofError).call(this, 'non-terminal isolated node in proof'));
        break;

      default:
        _this2 = (0, _possibleConstructorReturn2["default"])(this, (0, _getPrototypeOf2["default"])(MapProofError).call(this, type));
    }

    return _this2;
  }

  return MapProofError;
}((0, _wrapNativeSuper2["default"])(Error));

exports.MapProofError = MapProofError;