construct-byob-request.any.js

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// META: global=window,worker,shadowrealm

// META: script=../resources/rs-utils.js

'use strict';

// Prior to whatwg/stream#870 it was possible to construct a ReadableStreamBYOBRequest directly. This made it possible

// to construct requests that were out-of-sync with the state of the ReadableStream. They could then be used to call

// internal operations, resulting in asserts or bad behaviour. This file contains regression tests for the change.

function getRealByteStreamController() {

  let controller;

  new ReadableStream({

    start(c) {

      controller = c;

},

    type: 'bytes'

});

  return controller;

// Create an object pretending to have prototype |prototype|, of type |type|. |type| is one of "undefined", "null",

// "fake", or "real". "real" will call the realObjectCreator function to get a real instance of the object.

function createDummyObject(prototype, type, realObjectCreator) {

  switch (type) {

    case 'undefined':

      return undefined;

    case 'null':

      return null;

    case 'fake':

      return Object.create(prototype);

    case 'real':

      return realObjectCreator();

  throw new Error('not reached');

const dummyTypes = ['undefined', 'null', 'fake', 'real'];

for (const controllerType of dummyTypes) {

  const controller = createDummyObject(ReadableByteStreamController.prototype, controllerType,

                                        getRealByteStreamController);

  for (const viewType of dummyTypes) {

    const view = createDummyObject(Uint8Array.prototype, viewType, () => new Uint8Array(16));

    test(() => {

      assert_throws_js(TypeError, () => new ReadableStreamBYOBRequest(controller, view),

                        'constructor should throw');

    }, `ReadableStreamBYOBRequest constructor should throw when passed a ${controllerType} ` +

        `ReadableByteStreamController and a ${viewType} view`);