prepack/lib/intrinsics/node/utils.js

Execute a JS bundle, serialize global state and side effects to a snapshot that can be quickly restored.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.getNodeBufferFromTypedArray = getNodeBufferFromTypedArray;
exports.createDeepIntrinsic = createDeepIntrinsic;
exports.copyProperty = copyProperty;

var _invariant = require("../../invariant.js");

var _invariant2 = _interopRequireDefault(_invariant);

var _errors = require("../../errors.js");

var _index = require("../../values/index.js");

var _singletons = require("../../singletons.js");

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * Copyright (c) 2017-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

function getNodeBufferFromTypedArray(realm, value) {
  let buffer = value.$ViewedArrayBuffer;
  (0, _invariant2.default)(buffer instanceof _index.ObjectValue && buffer.$ArrayBufferData);
  return buffer.$ArrayBufferData;
}

// Takes a value from the host realm and create it into a Prepack Realm.
// TODO: Move this to a bigger general purpose proxy between the environments.
// See issue #644 for more details.
function createDeepIntrinsic(realm, value, intrinsicName) {
  switch (typeof value) {
    case "undefined":
      return realm.intrinsics.undefined;
    case "boolean":
      return new _index.BooleanValue(realm, value, intrinsicName);
    case "number":
      return new _index.NumberValue(realm, value, intrinsicName);
    case "string":
      return new _index.StringValue(realm, value, intrinsicName);
    // $FlowFixMe flow doesn't understand symbols.
    case "symbol":
      throw new _errors.FatalError("Symbol cannot be safely cloned.");
    case "function":
      throw new _errors.FatalError("Functions could be supported but are not yet.");
    case "object":
      {
        if (value === null) {
          return realm.intrinsics.null;
        }
        if (Array.isArray(value)) {
          throw new _errors.FatalError("Arrays are not supported yet.");
        }
        let prototype = Object.getPrototypeOf(value);
        if (prototype !== Object.prototype) {
          throw new _errors.FatalError("Only simple objects are supported for now. Got: " + (typeof prototype.constructor === "function" && prototype.constructor.name || Object.prototype.toString.call(prototype)));
        }
        let obj = new _index.ObjectValue(realm, realm.intrinsics.ObjectPrototype, intrinsicName // We use the intrinsic name for Objects to preserve their referential equality
        );
        let names = Object.getOwnPropertyNames(value);
        for (let name of names) {
          // We intentionally invoke the getter on value[name] which resolves any
          // lazy getters.
          let newValue = createDeepIntrinsic(realm, value[name], intrinsicName + "." + name);
          copyProperty(realm, value, obj, name, newValue);
        }
        return obj;
      }
    default:
      (0, _invariant2.default)(false);
  }
}

// Define a value with the same descriptor settings as the original object.
function copyProperty(realm, originalObject, realmObject, name, value) {
  let desc = Object.getOwnPropertyDescriptor(originalObject, name);
  if (!desc) {
    return;
  }
  if (desc.get || desc.set) {
    throw new _errors.FatalError("Getter/setters are not supported because functions are not supported yet.");
  }
  let newDesc = {
    value: value,
    writable: !!desc.writable,
    configurable: !!desc.configurable,
    enumerable: !!desc.enumerable
  };
  _singletons.Properties.DefinePropertyOrThrow(realm, realmObject, name, newDesc);
}
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