test_blob_sliced_from_parent_process.js

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"use strict";

const { XPCShellContentUtils } = ChromeUtils.importESModule(

  "resource://testing-common/XPCShellContentUtils.sys.mjs"

);

XPCShellContentUtils.init(this);

function childFrameScript() {

  /* eslint-env mozilla/frame-script */

  const messageName = "test:blob-slice-test";

  const blobData = ["So", " ", "many", " ", "blobs!"];

  const blobText = blobData.join("");

  const blobType = "text/plain";

  const sliceText = "an";

  function info(msg) {

    sendAsyncMessage(messageName, { op: "info", msg });

  function ok(condition, name, diag) {

    sendAsyncMessage(messageName, { op: "ok", condition, name, diag });

  function is(a, b, name) {

    let pass = a == b;

    let diag = pass ? "" : "got " + a + ", expected " + b;

    ok(pass, name, diag);

  function finish(result) {

    sendAsyncMessage(messageName, { op: "done", result });

  function grabAndContinue(arg) {

    testGenerator.next(arg);

  function* testSteps() {

    addMessageListener(messageName, grabAndContinue);

    let message = yield undefined;

    let blob = message.data;

    ok(Blob.isInstance(blob), "Received a Blob");

    is(blob.size, blobText.length, "Blob has correct length");

    is(blob.type, blobType, "Blob has correct type");

    info("Reading blob");

    let reader = new FileReader();

    reader.addEventListener("load", grabAndContinue);

    reader.readAsText(blob);

    yield undefined;

    is(reader.result, blobText, "Blob has correct data");

    let firstSliceStart = blobData[0].length + blobData[1].length;

    let firstSliceEnd = firstSliceStart + blobData[2].length;

    let slice = blob.slice(firstSliceStart, firstSliceEnd, blobType);

    ok(Blob.isInstance(slice), "Slice returned a Blob");

    is(slice.size, blobData[2].length, "Slice has correct length");

    is(slice.type, blobType, "Slice has correct type");

    info("Reading slice");

    reader = new FileReader();

    reader.addEventListener("load", grabAndContinue);

    reader.readAsText(slice);

    yield undefined;

    is(reader.result, blobData[2], "Slice has correct data");

    let secondSliceStart = blobData[2].indexOf("a");

    let secondSliceEnd = secondSliceStart + sliceText.length;

    slice = slice.slice(secondSliceStart, secondSliceEnd, blobType);

    ok(Blob.isInstance(slice), "Second slice returned a Blob");

    is(slice.size, sliceText.length, "Second slice has correct length");

    is(slice.type, blobType, "Second slice has correct type");

    info("Sending second slice");

    finish(slice);

  let testGenerator = testSteps();

  testGenerator.next();

add_task(async function test() {

  let page = await XPCShellContentUtils.loadContentPage(

    "data:text/html,<!DOCTYPE HTML><html><body></body></html>",

      remote: true,

);

  page.loadFrameScript(childFrameScript);

  const messageName = "test:blob-slice-test";

  const blobData = ["So", " ", "many", " ", "blobs!"];

  const blobType = "text/plain";

  const sliceText = "an";

  await new Promise(resolve => {

    function grabAndContinue(arg) {

      testGenerator.next(arg);

    function* testSteps() {

      let slice = yield undefined;

      ok(Blob.isInstance(slice), "Received a Blob");

      equal(slice.size, sliceText.length, "Slice has correct size");

      equal(slice.type, blobType, "Slice has correct type");

      let reader = new FileReader();

      reader.onload = grabAndContinue;

      reader.readAsText(slice);

      yield undefined;

      equal(reader.result, sliceText, "Slice has correct data");

      resolve();

    let testGenerator = testSteps();

    testGenerator.next();

    let mm = page.browser.messageManager;

    mm.addMessageListener(messageName, function (message) {

      let data = message.data;

      switch (data.op) {

        case "info": {

          info(data.msg);

          break;

        case "ok": {

          ok(data.condition, data.name + " - " + data.diag);

          break;

        case "done": {

          testGenerator.next(data.result);

          break;

        default: {

          ok(false, "Unknown op: " + data.op);

          resolve();

});

    let blob = new Blob(blobData, { type: blobType });

    mm.sendAsyncMessage(messageName, blob);

});

  await page.close();

});