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denoland-deno/core/00_primordials.js

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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
// Based on https://github.com/nodejs/node/blob/889ad35d3d41e376870f785b0c1b669cb732013d/lib/internal/per_context/primordials.js
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
// 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
"use strict";
(() => {
const primordials = {};
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",
"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}`, {
value: uncurryThis(get),
enumerable,
});
if (set !== undefined) {
ReflectDefineProperty(dest, `${prefix}Set${key}`, {
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, desc);
if (varargsMethods.includes(name)) {
ReflectDefineProperty(dest, `${name}Apply`, {
// `src` is bound as the `this` so that the static `this` points
// to the object it was defined on,
// e.g.: `ArrayOfApply` gets a `this` of `Array`:
value: applyBind(desc.value, src),
});
}
}
}
}
function copyPropsRenamedBound(src, dest, prefix) {
for (const key of ReflectOwnKeys(src)) {
const newKey = getNewKey(key);
const desc = ReflectGetOwnPropertyDescriptor(src, key);
if ("get" in desc) {
copyAccessor(dest, prefix, newKey, desc);
} else {
const { value } = desc;
if (typeof value === "function") {
desc.value = value.bind(src);
}
const name = `${prefix}${newKey}`;
ReflectDefineProperty(dest, name, desc);
if (varargsMethods.includes(name)) {
ReflectDefineProperty(dest, `${name}Apply`, {
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, desc);
if (varargsMethods.includes(name)) {
ReflectDefineProperty(dest, `${name}Apply`, {
value: applyBind(value),
});
}
}
}
}
// Create copies of configurable value properties of the global object
[
"Proxy",
"globalThis",
].forEach((name) => {
primordials[name] = globalThis[name];
});
// Create copy of isNaN
primordials[isNaN.name] = isNaN;
// Create copy of queueMicrotask
primordials["queueMicrotask"] = queueMicrotask;
// Create copies of URI handling functions
[
decodeURI,
decodeURIComponent,
encodeURI,
encodeURIComponent,
].forEach((fn) => {
primordials[fn.name] = fn;
});
// Create copies of the namespace objects
[
"JSON",
"Math",
"Proxy",
"Reflect",
].forEach((name) => {
copyPropsRenamed(globalThis[name], primordials, name);
});
// Create copies of intrinsic objects
[
"AggregateError",
"Array",
"ArrayBuffer",
"BigInt",
"BigInt64Array",
"BigUint64Array",
"Boolean",
"DataView",
"Date",
"Error",
"EvalError",
"FinalizationRegistry",
"Float32Array",
"Float64Array",
"Function",
"Int16Array",
"Int32Array",
"Int8Array",
"Map",
"Number",
"Object",
"RangeError",
"ReferenceError",
"RegExp",
"Set",
"String",
"Symbol",
"SyntaxError",
"TypeError",
"URIError",
"Uint16Array",
"Uint32Array",
"Uint8Array",
"Uint8ClampedArray",
"WeakMap",
"WeakRef",
"WeakSet",
].forEach((name) => {
const original = globalThis[name];
primordials[name] = original;
copyPropsRenamed(original, primordials, name);
copyPrototype(original.prototype, primordials, `${name}Prototype`);
});
// 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) => {
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`);
});
const {
ArrayPrototypeForEach,
FunctionPrototypeCall,
Map,
ObjectFreeze,
ObjectSetPrototypeOf,
Promise,
PromisePrototypeThen,
Set,
SymbolIterator,
WeakMap,
WeakSet,
} = primordials;
// 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:
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,
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, 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);
}
},
);
primordials.SafeWeakMap = makeSafe(
WeakMap,
class SafeWeakMap extends WeakMap {
constructor(i) {
super(i);
}
},
);
primordials.SafeSet = makeSafe(
Set,
class SafeSet extends Set {
constructor(i) {
super(i);
}
},
);
primordials.SafeWeakSet = makeSafe(
WeakSet,
class SafeWeakSet extends WeakSet {
constructor(i) {
super(i);
}
},
);
primordials.SafeFinalizationRegistry = makeSafe(
FinalizationRegistry,
class SafeFinalizationRegistry extends FinalizationRegistry {
constructor(cleanupCallback) {
super(cleanupCallback);
}
},
);
primordials.SafeWeakRef = makeSafe(
WeakRef,
class SafeWeakRef extends WeakRef {
constructor(target) {
super(target);
}
},
);
const SafePromise = makeSafe(
Promise,
class SafePromise extends Promise {
constructor(executor) {
super(executor);
}
},
);
primordials.PromisePrototypeCatch = (thisPromise, onRejected) =>
PromisePrototypeThen(thisPromise, undefined, onRejected);
/**
* 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 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)
);
ObjectSetPrototypeOf(primordials, null);
ObjectFreeze(primordials);
// Provide bootstrap namespace
globalThis.__bootstrap = { primordials };
})();