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// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.import { validateFunction } from "./validators.mjs";import { normalizeEncoding, slowCases } from "./normalize_encoding.mjs";export { normalizeEncoding, slowCases };import { ObjectCreate, StringPrototypeToUpperCase } from "./primordials.mjs";import { ERR_UNKNOWN_SIGNAL } from "./errors.ts";import { os } from "../internal_binding/constants.ts";
const { signals } = os;
export const customInspectSymbol = Symbol.for("nodejs.util.inspect.custom");export const kEnumerableProperty = Object.create(null);kEnumerableProperty.enumerable = true;
export const kEmptyObject = Object.freeze(Object.create(null));
export function once(callback) {  let called = false;  return function (...args) {    if (called) return;    called = true;    Reflect.apply(callback, this, args);  };}
export function createDeferredPromise() {  let resolve;  let reject;  const promise = new Promise((res, rej) => {    resolve = res;    reject = rej;  });
  return { promise, resolve, reject };}
// In addition to being accessible through util.promisify.custom,// this symbol is registered globally and can be accessed in any environment as// Symbol.for('nodejs.util.promisify.custom').const kCustomPromisifiedSymbol = Symbol.for("nodejs.util.promisify.custom");// This is an internal Node symbol used by functions returning multiple// arguments, e.g. ['bytesRead', 'buffer'] for fs.read().const kCustomPromisifyArgsSymbol = Symbol.for(  "nodejs.util.promisify.customArgs",);
export const customPromisifyArgs = kCustomPromisifyArgsSymbol;
export function promisify(  original,) {  validateFunction(original, "original");  if (original[kCustomPromisifiedSymbol]) {    const fn = original[kCustomPromisifiedSymbol];
    validateFunction(fn, "util.promisify.custom");
    return Object.defineProperty(fn, kCustomPromisifiedSymbol, {      value: fn,      enumerable: false,      writable: false,      configurable: true,    });  }
  // Names to create an object from in case the callback receives multiple  // arguments, e.g. ['bytesRead', 'buffer'] for fs.read.  const argumentNames = original[kCustomPromisifyArgsSymbol];  function fn(...args) {    return new Promise((resolve, reject) => {      args.push((err, ...values) => {        if (err) {          return reject(err);        }        if (argumentNames !== undefined && values.length > 1) {          const obj = {};          for (let i = 0; i < argumentNames.length; i++) {            obj[argumentNames[i]] = values[i];          }          resolve(obj);        } else {          resolve(values[0]);        }      });      Reflect.apply(original, this, args);    });  }
  Object.setPrototypeOf(fn, Object.getPrototypeOf(original));
  Object.defineProperty(fn, kCustomPromisifiedSymbol, {    value: fn,    enumerable: false,    writable: false,    configurable: true,  });  return Object.defineProperties(    fn,    Object.getOwnPropertyDescriptors(original),  );}
let signalsToNamesMapping;function getSignalsToNamesMapping() {  if (signalsToNamesMapping !== undefined) {    return signalsToNamesMapping;  }
  signalsToNamesMapping = ObjectCreate(null);  for (const key in signals) {    signalsToNamesMapping[signals[key]] = key;  }
  return signalsToNamesMapping;}
export function convertToValidSignal(signal) {  if (typeof signal === "number" && getSignalsToNamesMapping()[signal]) {    return signal;  }
  if (typeof signal === "string") {    const signalName = signals[StringPrototypeToUpperCase(signal)];    if (signalName) return signalName;  }
  throw new ERR_UNKNOWN_SIGNAL(signal);}
promisify.custom = kCustomPromisifiedSymbol;
export default {  convertToValidSignal,  createDeferredPromise,  customInspectSymbol,  customPromisifyArgs,  kEmptyObject,  kEnumerableProperty,  normalizeEncoding,  once,  promisify,  slowCases,};