primordials.js

'use strict';

/* eslint-disable node-core/prefer-primordials */

// This file subclasses and stores the JS builtins that come from the VM
// so that Node.js's builtin modules do not need to later look these up from
// the global proxy, which can be mutated by users.

// Use of primordials have sometimes a dramatic impact on performance, please
// benchmark all changes made in performance-sensitive areas of the codebase.
// See: https://github.com/nodejs/node/pull/38248

const {
  defineProperty: ReflectDefineProperty,
  getOwnPropertyDescriptor: ReflectGetOwnPropertyDescriptor,
  ownKeys: ReflectOwnKeys,
} = Reflect;

// `uncurryThis` is equivalent to `func => Function.prototype.call.bind(func)`.
// It is using `bind.bind(call)` to avoid using `Function.prototype.bind`
// and `Function.prototype.call` after it may have been mutated by users.
const { apply, bind, call } = Function.prototype;
const uncurryThis = bind.bind(call);
primordials.uncurryThis = uncurryThis;

// `applyBind` is equivalent to `func => Function.prototype.apply.bind(func)`.
// It is using `bind.bind(apply)` to avoid using `Function.prototype.bind`
// and `Function.prototype.apply` after it may have been mutated by users.
const applyBind = bind.bind(apply);
primordials.applyBind = applyBind;

// Methods that accept a variable number of arguments, and thus it's useful to
// also create `${prefix}${key}Apply`, which uses `Function.prototype.apply`,
// instead of `Function.prototype.call`, and thus doesn't require iterator
// destructuring.
const varargsMethods = [
  // 'ArrayPrototypeConcat' is omitted, because it performs the spread
  // on its own for arrays and array-likes with a truthy
  // @@isConcatSpreadable symbol property.
  'ArrayOf',
  'ArrayPrototypePush',
  'ArrayPrototypeUnshift',
  // 'FunctionPrototypeCall' is omitted, since there's 'ReflectApply'
  // and 'FunctionPrototypeApply'.
  'MathHypot',
  'MathMax',
  'MathMin',
  'StringFromCharCode',
  'StringFromCodePoint',
  'StringPrototypeConcat',
  'TypedArrayOf',
];

function getNewKey(key) {
  return typeof key === 'symbol' ?
    `Symbol${key.description[7].toUpperCase()}${key.description.slice(8)}` :
    `${key[0].toUpperCase()}${key.slice(1)}`;
}

function copyAccessor(dest, prefix, key, { enumerable, get, set }) {
  ReflectDefineProperty(dest, `${prefix}Get${key}`, {
    __proto__: null,
    value: uncurryThis(get),
    enumerable,
  });
  if (set !== undefined) {
    ReflectDefineProperty(dest, `${prefix}Set${key}`, {
      __proto__: null,
      value: uncurryThis(set),
      enumerable,
    });
  }
}

function copyPropsRenamed(src, dest, prefix) {
  for (const key of ReflectOwnKeys(src)) {
    const newKey = getNewKey(key);
    const desc = ReflectGetOwnPropertyDescriptor(src, key);
    if ('get' in desc) {
      copyAccessor(dest, prefix, newKey, desc);
    } else {
      const name = `${prefix}${newKey}`;
      ReflectDefineProperty(dest, name, { __proto__: null, ...desc });
      if (varargsMethods.includes(name)) {
        ReflectDefineProperty(dest, `${name}Apply`, {
          __proto__: null,
          // `src` is bound as the `this` so that the static `this` points
          // to the object it was defined on,
          // e.g.: `ArrayOfApply` gets a `this` of `Array`:
          value: applyBind(desc.value, src),
        });
      }
    }
  }
}

function copyPropsRenamedBound(src, dest, prefix) {
  for (const key of ReflectOwnKeys(src)) {
    const newKey = getNewKey(key);
    const desc = ReflectGetOwnPropertyDescriptor(src, key);
    if ('get' in desc) {
      copyAccessor(dest, prefix, newKey, desc);
    } else {
      const { value } = desc;
      if (typeof value === 'function') {
        desc.value = value.bind(src);
      }

      const name = `${prefix}${newKey}`;
      ReflectDefineProperty(dest, name, { __proto__: null, ...desc });
      if (varargsMethods.includes(name)) {
        ReflectDefineProperty(dest, `${name}Apply`, {
          __proto__: null,
          value: applyBind(value, src),
        });
      }
    }
  }
}

function copyPrototype(src, dest, prefix) {
  for (const key of ReflectOwnKeys(src)) {
    const newKey = getNewKey(key);
    const desc = ReflectGetOwnPropertyDescriptor(src, key);
    if ('get' in desc) {
      copyAccessor(dest, prefix, newKey, desc);
    } else {
      const { value } = desc;
      if (typeof value === 'function') {
        desc.value = uncurryThis(value);
      }

      const name = `${prefix}${newKey}`;
      ReflectDefineProperty(dest, name, { __proto__: null, ...desc });
      if (varargsMethods.includes(name)) {
        ReflectDefineProperty(dest, `${name}Apply`, {
          __proto__: null,
          value: applyBind(value),
        });
      }
    }
  }
}

// Create copies of configurable value properties of the global object
[
  'Proxy',
  'globalThis',
].forEach((name) => {
  // eslint-disable-next-line no-restricted-globals
  primordials[name] = globalThis[name];
});

// Create copies of URI handling functions
[
  decodeURI,
  decodeURIComponent,
  encodeURI,
  encodeURIComponent,
].forEach((fn) => {
  primordials[fn.name] = fn;
});

// Create copies of legacy functions
[
  escape,
  eval,
  unescape,
].forEach((fn) => {
  primordials[fn.name] = fn;
});

// Create copies of the namespace objects
[
  'JSON',
  'Math',
  'Proxy',
  'Reflect',
].forEach((name) => {
  // eslint-disable-next-line no-restricted-globals
  copyPropsRenamed(globalThis[name], primordials, name);
});

// Create copies of intrinsic objects
[
  'AggregateError',
  'Array',
  'ArrayBuffer',
  'BigInt',
  'BigInt64Array',
  'BigUint64Array',
  'Boolean',
  'DataView',
  'Date',
  'Error',
  'EvalError',
  'FinalizationRegistry',
  'Float32Array',
  'Float64Array',
  'Function',
  'Int16Array',
  'Int32Array',
  'Int8Array',
  'Map',
  'Number',
  'Object',
  'RangeError',
  'ReferenceError',
  'RegExp',
  'Set',
  'String',
  'Symbol',
  'SyntaxError',
  'TypeError',
  'URIError',
  'Uint16Array',
  'Uint32Array',
  'Uint8Array',
  'Uint8ClampedArray',
  'WeakMap',
  'WeakRef',
  'WeakSet',
].forEach((name) => {
  // eslint-disable-next-line no-restricted-globals
  const original = globalThis[name];
  primordials[name] = original;
  copyPropsRenamed(original, primordials, name);
  copyPrototype(original.prototype, primordials, `${name}Prototype`);
});

// Define Symbol.dispose and Symbol.asyncDispose
// Until these are defined by the environment.
// TODO(MoLow): Remove this polyfill once Symbol.dispose and Symbol.asyncDispose are available in V8.
primordials.SymbolDispose ??= primordials.SymbolFor('nodejs.dispose');
primordials.SymbolAsyncDispose ??= primordials.SymbolFor('nodejs.asyncDispose');

// Create copies of intrinsic objects that require a valid `this` to call
// static methods.
// Refs: https://www.ecma-international.org/ecma-262/#sec-promise.all
[
  'Promise',
].forEach((name) => {
  // eslint-disable-next-line no-restricted-globals
  const original = globalThis[name];
  primordials[name] = original;
  copyPropsRenamedBound(original, primordials, name);
  copyPrototype(original.prototype, primordials, `${name}Prototype`);
});

// Create copies of abstract intrinsic objects that are not directly exposed
// on the global object.
// Refs: https://tc39.es/ecma262/#sec-%typedarray%-intrinsic-object
[
  { name: 'TypedArray', original: Reflect.getPrototypeOf(Uint8Array) },
  { name: 'ArrayIterator', original: {
    prototype: Reflect.getPrototypeOf(Array.prototype[Symbol.iterator]()),
  } },
  { name: 'StringIterator', original: {
    prototype: Reflect.getPrototypeOf(String.prototype[Symbol.iterator]()),
  } },
].forEach(({ name, original }) => {
  primordials[name] = original;
  // The static %TypedArray% methods require a valid `this`, but can't be bound,
  // as they need a subclass constructor as the receiver:
  copyPrototype(original, primordials, name);
  copyPrototype(original.prototype, primordials, `${name}Prototype`);
});

primordials.IteratorPrototype = Reflect.getPrototypeOf(primordials.ArrayIteratorPrototype);

/* eslint-enable node-core/prefer-primordials */

const {
  Array: ArrayConstructor,
  ArrayPrototypeForEach,
  ArrayPrototypeMap,
  FinalizationRegistry,
  FunctionPrototypeCall,
  Map,
  ObjectDefineProperties,
  ObjectDefineProperty,
  ObjectFreeze,
  ObjectSetPrototypeOf,
  Promise,
  PromisePrototypeThen,
  PromiseResolve,
  ReflectApply,
  ReflectConstruct,
  ReflectSet,
  ReflectGet,
  RegExp,
  RegExpPrototype,
  RegExpPrototypeExec,
  RegExpPrototypeGetDotAll,
  RegExpPrototypeGetFlags,
  RegExpPrototypeGetGlobal,
  RegExpPrototypeGetHasIndices,
  RegExpPrototypeGetIgnoreCase,
  RegExpPrototypeGetMultiline,
  RegExpPrototypeGetSource,
  RegExpPrototypeGetSticky,
  RegExpPrototypeGetUnicode,
  Set,
  SymbolIterator,
  SymbolMatch,
  SymbolMatchAll,
  SymbolReplace,
  SymbolSearch,
  SymbolSpecies,
  SymbolSplit,
  WeakMap,
  WeakRef,
  WeakSet,
} = primordials;


/**
 * Creates a class that can be safely iterated over.
 *
 * Because these functions are used by `makeSafe`, which is exposed on the
 * `primordials` object, it's important to use const references to the
 * primordials that they use.
 * @template {Iterable} T
 * @template {*} TReturn
 * @template {*} TNext
 * @param {(self: T) => IterableIterator<T>} factory
 * @param {(...args: [] | [TNext]) => IteratorResult<T, TReturn>} next
 * @returns {Iterator<T, TReturn, TNext>}
 */
const createSafeIterator = (factory, next) => {
  class SafeIterator {
    constructor(iterable) {
      this._iterator = factory(iterable);
    }
    next() {
      return next(this._iterator);
    }
    [SymbolIterator]() {
      return this;
    }
  }
  ObjectSetPrototypeOf(SafeIterator.prototype, null);
  ObjectFreeze(SafeIterator.prototype);
  ObjectFreeze(SafeIterator);
  return SafeIterator;
};

primordials.SafeArrayIterator = createSafeIterator(
  primordials.ArrayPrototypeSymbolIterator,
  primordials.ArrayIteratorPrototypeNext,
);
primordials.SafeStringIterator = createSafeIterator(
  primordials.StringPrototypeSymbolIterator,
  primordials.StringIteratorPrototypeNext,
);

const copyProps = (src, dest) => {
  ArrayPrototypeForEach(ReflectOwnKeys(src), (key) => {
    if (!ReflectGetOwnPropertyDescriptor(dest, key)) {
      ReflectDefineProperty(
        dest,
        key,
        { __proto__: null, ...ReflectGetOwnPropertyDescriptor(src, key) });
    }
  });
};

/**
 * @type {typeof primordials.makeSafe}
 */
const makeSafe = (unsafe, safe) => {
  if (SymbolIterator in unsafe.prototype) {
    const dummy = new unsafe();
    let next; // We can reuse the same `next` method.

    ArrayPrototypeForEach(ReflectOwnKeys(unsafe.prototype), (key) => {
      if (!ReflectGetOwnPropertyDescriptor(safe.prototype, key)) {
        const desc = ReflectGetOwnPropertyDescriptor(unsafe.prototype, key);
        if (
          typeof desc.value === 'function' &&
          desc.value.length === 0 &&
          SymbolIterator in (FunctionPrototypeCall(desc.value, dummy) ?? {})
        ) {
          const createIterator = uncurryThis(desc.value);
          next ??= uncurryThis(createIterator(dummy).next);
          const SafeIterator = createSafeIterator(createIterator, next);
          desc.value = function() {
            return new SafeIterator(this);
          };
        }
        ReflectDefineProperty(safe.prototype, key, { __proto__: null, ...desc });
      }
    });
  } else {
    copyProps(unsafe.prototype, safe.prototype);
  }
  copyProps(unsafe, safe);

  ObjectSetPrototypeOf(safe.prototype, null);
  ObjectFreeze(safe.prototype);
  ObjectFreeze(safe);
  return safe;
};
primordials.makeSafe = makeSafe;

// Subclass the constructors because we need to use their prototype
// methods later.
// Defining the `constructor` is necessary here to avoid the default
// constructor which uses the user-mutable `%ArrayIteratorPrototype%.next`.
primordials.SafeMap = makeSafe(
  Map,
  class SafeMap extends Map {
    constructor(i) { super(i); } // eslint-disable-line no-useless-constructor
  },
);
primordials.SafeWeakMap = makeSafe(
  WeakMap,
  class SafeWeakMap extends WeakMap {
    constructor(i) { super(i); } // eslint-disable-line no-useless-constructor
  },
);

primordials.SafeSet = makeSafe(
  Set,
  class SafeSet extends Set {
    constructor(i) { super(i); } // eslint-disable-line no-useless-constructor
  },
);
primordials.SafeWeakSet = makeSafe(
  WeakSet,
  class SafeWeakSet extends WeakSet {
    constructor(i) { super(i); } // eslint-disable-line no-useless-constructor
  },
);

primordials.SafeFinalizationRegistry = makeSafe(
  FinalizationRegistry,
  class SafeFinalizationRegistry extends FinalizationRegistry {
    // eslint-disable-next-line no-useless-constructor
    constructor(cleanupCallback) { super(cleanupCallback); }
  },
);
primordials.SafeWeakRef = makeSafe(
  WeakRef,
  class SafeWeakRef extends WeakRef {
    // eslint-disable-next-line no-useless-constructor
    constructor(target) { super(target); }
  },
);

const SafePromise = makeSafe(
  Promise,
  class SafePromise extends Promise {
    // eslint-disable-next-line no-useless-constructor
    constructor(executor) { super(executor); }
  },
);

/**
 * Attaches a callback that is invoked when the Promise is settled (fulfilled or
 * rejected). The resolved value cannot be modified from the callback.
 * Prefer using async functions when possible.
 * @param {Promise<any>} thisPromise
 * @param {() => void) | undefined | null} onFinally The callback to execute
 *        when the Promise is settled (fulfilled or rejected).
 * @returns {Promise} A Promise for the completion of the callback.
 */
primordials.SafePromisePrototypeFinally = (thisPromise, onFinally) =>
  // Wrapping on a new Promise is necessary to not expose the SafePromise
  // prototype to user-land.
  new Promise((a, b) =>
    new SafePromise((a, b) => PromisePrototypeThen(thisPromise, a, b))
      .finally(onFinally)
      .then(a, b),
  );

primordials.AsyncIteratorPrototype =
  primordials.ReflectGetPrototypeOf(
    primordials.ReflectGetPrototypeOf(
      async function* () {}).prototype);

const arrayToSafePromiseIterable = (promises, mapFn) =>
  new primordials.SafeArrayIterator(
    ArrayPrototypeMap(
      promises,
      (promise, i) =>
        new SafePromise((a, b) => PromisePrototypeThen(mapFn == null ? promise : mapFn(promise, i), a, b)),
    ),
  );

/**
 * @template T,U
 * @param {Array<T | PromiseLike<T>>} promises
 * @param {(v: T|PromiseLike<T>, k: number) => U|PromiseLike<U>} [mapFn]
 * @returns {Promise<Awaited<U>[]>}
 */
primordials.SafePromiseAll = (promises, mapFn) =>
  // Wrapping on a new Promise is necessary to not expose the SafePromise
  // prototype to user-land.
  new Promise((a, b) =>
    SafePromise.all(arrayToSafePromiseIterable(promises, mapFn)).then(a, b),
  );

/**
 * Should only be used for internal functions, this would produce similar
 * results as `Promise.all` but without prototype pollution, and the return
 * value is not a genuine Array but an array-like object.
 * @template T,U
 * @param {ArrayLike<T | PromiseLike<T>>} promises
 * @param {(v: T|PromiseLike<T>, k: number) => U|PromiseLike<U>} [mapFn]
 * @returns {Promise<ArrayLike<Awaited<U>>>}
 */
primordials.SafePromiseAllReturnArrayLike = (promises, mapFn) =>
  new Promise((resolve, reject) => {
    const { length } = promises;

    const returnVal = ArrayConstructor(length);
    ObjectSetPrototypeOf(returnVal, null);
    if (length === 0) resolve(returnVal);

    let pendingPromises = length;
    for (let i = 0; i < length; i++) {
      const promise = mapFn != null ? mapFn(promises[i], i) : promises[i];
      PromisePrototypeThen(PromiseResolve(promise), (result) => {
        returnVal[i] = result;
        if (--pendingPromises === 0) resolve(returnVal);
      }, reject);
    }
  });

/**
 * Should only be used when we only care about waiting for all the promises to
 * resolve, not what value they resolve to.
 * @template T,U
 * @param {ArrayLike<T | PromiseLike<T>>} promises
 * @param {(v: T|PromiseLike<T>, k: number) => U|PromiseLike<U>} [mapFn]
 * @returns {Promise<void>}
 */
primordials.SafePromiseAllReturnVoid = (promises, mapFn) =>
  new Promise((resolve, reject) => {
    let pendingPromises = promises.length;
    if (pendingPromises === 0) resolve();
    for (let i = 0; i < promises.length; i++) {
      const promise = mapFn != null ? mapFn(promises[i], i) : promises[i];
      PromisePrototypeThen(PromiseResolve(promise), () => {
        if (--pendingPromises === 0) resolve();
      }, reject);
    }
  });

/**
 * @template T,U
 * @param {Array<T|PromiseLike<T>>} promises
 * @param {(v: T|PromiseLike<T>, k: number) => U|PromiseLike<U>} [mapFn]
 * @returns {Promise<PromiseSettledResult<any>[]>}
 */
primordials.SafePromiseAllSettled = (promises, mapFn) =>
  // Wrapping on a new Promise is necessary to not expose the SafePromise
  // prototype to user-land.
  new Promise((a, b) =>
    SafePromise.allSettled(arrayToSafePromiseIterable(promises, mapFn)).then(a, b),
  );

/**
 * Should only be used when we only care about waiting for all the promises to
 * settle, not what value they resolve or reject to.
 * @template T,U
 * @param {ArrayLike<T|PromiseLike<T>>} promises
 * @param {(v: T|PromiseLike<T>, k: number) => U|PromiseLike<U>} [mapFn]
 * @returns {Promise<void>}
 */
primordials.SafePromiseAllSettledReturnVoid = async (promises, mapFn) => {
  await primordials.SafePromiseAllSettled(promises, mapFn);
};

/**
 * @template T,U
 * @param {Array<T|PromiseLike<T>>} promises
 * @param {(v: T|PromiseLike<T>, k: number) => U|PromiseLike<U>} [mapFn]
 * @returns {Promise<Awaited<U>>}
 */
primordials.SafePromiseAny = (promises, mapFn) =>
  // Wrapping on a new Promise is necessary to not expose the SafePromise
  // prototype to user-land.
  new Promise((a, b) =>
    SafePromise.any(arrayToSafePromiseIterable(promises, mapFn)).then(a, b),
  );

/**
 * @template T,U
 * @param {Array<T|PromiseLike<T>>} promises
 * @param {(v: T|PromiseLike<T>, k: number) => U|PromiseLike<U>} [mapFn]
 * @returns {Promise<Awaited<U>>}
 */
primordials.SafePromiseRace = (promises, mapFn) =>
  // Wrapping on a new Promise is necessary to not expose the SafePromise
  // prototype to user-land.
  new Promise((a, b) =>
    SafePromise.race(arrayToSafePromiseIterable(promises, mapFn)).then(a, b),
  );


const {
  exec: OriginalRegExpPrototypeExec,
  [SymbolMatch]: OriginalRegExpPrototypeSymbolMatch,
  [SymbolMatchAll]: OriginalRegExpPrototypeSymbolMatchAll,
  [SymbolReplace]: OriginalRegExpPrototypeSymbolReplace,
  [SymbolSearch]: OriginalRegExpPrototypeSymbolSearch,
  [SymbolSplit]: OriginalRegExpPrototypeSymbolSplit,
} = RegExpPrototype;

class RegExpLikeForStringSplitting {
  #regex;
  constructor() {
    this.#regex = ReflectConstruct(RegExp, arguments);
  }

  get lastIndex() {
    return ReflectGet(this.#regex, 'lastIndex');
  }
  set lastIndex(value) {
    ReflectSet(this.#regex, 'lastIndex', value);
  }

  exec() {
    return ReflectApply(OriginalRegExpPrototypeExec, this.#regex, arguments);
  }
}
ObjectSetPrototypeOf(RegExpLikeForStringSplitting.prototype, null);

/**
 * @param {RegExp} pattern
 * @returns {RegExp}
 */
primordials.hardenRegExp = function hardenRegExp(pattern) {
  ObjectDefineProperties(pattern, {
    [SymbolMatch]: {
      __proto__: null,
      configurable: true,
      value: OriginalRegExpPrototypeSymbolMatch,
    },
    [SymbolMatchAll]: {
      __proto__: null,
      configurable: true,
      value: OriginalRegExpPrototypeSymbolMatchAll,
    },
    [SymbolReplace]: {
      __proto__: null,
      configurable: true,
      value: OriginalRegExpPrototypeSymbolReplace,
    },
    [SymbolSearch]: {
      __proto__: null,
      configurable: true,
      value: OriginalRegExpPrototypeSymbolSearch,
    },
    [SymbolSplit]: {
      __proto__: null,
      configurable: true,
      value: OriginalRegExpPrototypeSymbolSplit,
    },
    constructor: {
      __proto__: null,
      configurable: true,
      value: {
        [SymbolSpecies]: RegExpLikeForStringSplitting,
      },
    },
    dotAll: {
      __proto__: null,
      configurable: true,
      value: RegExpPrototypeGetDotAll(pattern),
    },
    exec: {
      __proto__: null,
      configurable: true,
      value: OriginalRegExpPrototypeExec,
    },
    global: {
      __proto__: null,
      configurable: true,
      value: RegExpPrototypeGetGlobal(pattern),
    },
    hasIndices: {
      __proto__: null,
      configurable: true,
      value: RegExpPrototypeGetHasIndices(pattern),
    },
    ignoreCase: {
      __proto__: null,
      configurable: true,
      value: RegExpPrototypeGetIgnoreCase(pattern),
    },
    multiline: {
      __proto__: null,
      configurable: true,
      value: RegExpPrototypeGetMultiline(pattern),
    },
    source: {
      __proto__: null,
      configurable: true,
      value: RegExpPrototypeGetSource(pattern),
    },
    sticky: {
      __proto__: null,
      configurable: true,
      value: RegExpPrototypeGetSticky(pattern),
    },
    unicode: {
      __proto__: null,
      configurable: true,
      value: RegExpPrototypeGetUnicode(pattern),
    },
  });
  ObjectDefineProperty(pattern, 'flags', {
    __proto__: null,
    configurable: true,
    value: RegExpPrototypeGetFlags(pattern),
  });
  return pattern;
};


/**
 * @param {string} str
 * @param {RegExp} regexp
 * @returns {number}
 */
primordials.SafeStringPrototypeSearch = (str, regexp) => {
  regexp.lastIndex = 0;
  const match = RegExpPrototypeExec(regexp, str);
  return match ? match.index : -1;
};

ObjectSetPrototypeOf(primordials, null);
ObjectFreeze(primordials);