test_blob_sliced_from_child_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 */

  "use strict";

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

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

  const blobType = "text/plain";

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

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

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

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

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

  let secondSliceEnd = secondSliceStart + 2;

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

  sendAsyncMessage(messageName, { blob });

  sendAsyncMessage(messageName, { slice });

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 blobText = blobData.join("");

  const blobType = "text/plain";

  const sliceText = "an";

  let receivedBlob = false;

  let receivedSlice = false;

  let resolveBlob, resolveSlice;

  let blobPromise = new Promise(resolve => {

    resolveBlob = resolve;

});

  let slicePromise = new Promise(resolve => {

    resolveSlice = resolve;

});

  let mm = page.browser.messageManager;

  mm.addMessageListener(messageName, function (message) {

    if ("blob" in message.data) {

      equal(receivedBlob, false, "Have not yet received Blob");

      equal(receivedSlice, false, "Have not yet received Slice");

      receivedBlob = true;

      let blob = message.data.blob;

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

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

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

      let slice = blob.slice(

        blobText.length - blobData[blobData.length - 1].length,

        blob.size,

        blobType

);

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

      equal(

        slice.size,

        blobData[blobData.length - 1].length,

        "Slice has correct size"

);

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

      let reader = new FileReader();

      reader.onload = function () {

        equal(

          reader.result,

          blobData[blobData.length - 1],

          "Slice has correct data"

);

        resolveBlob();

};

      reader.readAsText(slice);

    } else if ("slice" in message.data) {

      equal(receivedBlob, true, "Already received Blob");

      equal(receivedSlice, false, "Have not yet received Slice");

      receivedSlice = true;

      let slice = message.data.slice;

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

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

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

      let reader = new FileReader();

      reader.onload = function () {

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

        let slice2 = slice.slice(1, 2, blobType);

        ok(Blob.isInstance(slice2), "Slice returned a Blob");

        equal(slice2.size, 1, "Slice has correct size");

        equal(slice2.type, blobType, "Slice has correct type");

        let reader2 = new FileReader();

        reader2.onload = function () {

          equal(reader2.result, sliceText[1], "Slice has correct data");

          resolveSlice();

};

        reader2.readAsText(slice2);

};

      reader.readAsText(slice);

    } else {

      ok(false, "Received a bad message: " + JSON.stringify(message.data));

});

  await blobPromise;

  await slicePromise;

  await page.close();

});