Function readFile

lib/fs.js:401–436

* Asynchronously reads the entire contents of a file. * @param {string | Buffer | URL | number} path * @param {{ * encoding?: string | null; * flag?: string; * signal?: AbortSignal; * } | string} [options] * @param {( * err?: Error, * data?: string | Buffer * ) => any} callba

(path, options, callback)

 * @returns {void}
 */
function readFile(path, options, callback) {
  callback ||= options;
  validateFunction(callback, 'cb');

  const h = vfsState.handlers;
  if (h !== null) {
    const opts = typeof options === 'function' ? undefined : options;
    if (checkAborted(opts?.signal, callback)) return;
    if (vfsResult(h.readFile(path, opts), callback)) return;
  }

  options = getOptions(options, { flag: 'r' });
  validateReadFileBufferOptions(options);
  ReadFileContext ??= require('internal/fs/read/context');
  const context = new ReadFileContext(callback, options);
  context.isUserFd = isFd(path); // File descriptor ownership

  if (options.signal) {
    context.signal = options.signal;
  }
  if (context.isUserFd) {
    process.nextTick(function tick(context) {
      FunctionPrototypeCall(readFileAfterOpen, { context }, null, path);
    }, context);
    return;
  }

  if (checkAborted(options.signal, callback))
    return;

  const flagsNumber = stringToFlags(options.flag, 'options.flag');
  const req = new FSReqCallback();
  req.context = context;
  req.oncomplete = readFileAfterOpen;
  binding.open(getValidatedPath(path), flagsNumber, 0o666, req);
}

function tryStatSync(fd, isUserFd) {
  const stats = binding.fstat(fd, false, undefined, true /* shouldNotThrow */);