gecko-dev/dom/base/test/browser_inputStream_structuredClone.js

/* Any copyright is dedicated to the Public Domain.
 * http://creativecommons.org/publicdomain/zero/1.0/ */

const URIs = [
  "about:about",
  "http://example.com/browser/dom/base/test/empty.html",
];

async function runTest(input, url) {
  let tab = BrowserTestUtils.addTab(gBrowser, url);
  let browser = gBrowser.getBrowserForTab(tab);

  await BrowserTestUtils.browserLoaded(browser);

  let stream = Cc["@mozilla.org/io/string-input-stream;1"].createInstance(
    Ci.nsIStringInputStream
  );
  stream.setData(input, input.length);

  let data = {
    inputStream: stream,
  };

  is(
    data.inputStream.available(),
    input.length,
    "The length of the inputStream matches: " + input.length
  );

  // FIXME: SpecialPowers.spawn currently crashes when trying to return
  // values containing input streams.
  /* eslint-disable no-shadow */
  let dataBack = await ContentTask.spawn(browser, data, function (data) {
    let dataBack = {
      inputStream: data.inputStream,
      check: true,
    };

    if (content.location.href.startsWith("about:")) {
      dataBack.check =
        data.inputStream instanceof
        content.Components.interfaces.nsIInputStream;
    }

    return dataBack;
  });
  /* eslint-enable no-shadow */

  ok(dataBack.check, "The inputStream is a nsIInputStream also on content.");
  ok(
    data.inputStream instanceof Ci.nsIInputStream,
    "The original object was an inputStream"
  );
  ok(
    dataBack.inputStream instanceof Ci.nsIInputStream,
    "We have an inputStream back from the content."
  );

  BrowserTestUtils.removeTab(tab);
}

add_task(async function test() {
  let a = "a";
  for (let i = 0; i < 25; ++i) {
    a += a;
  }

  for (let i = 0; i < URIs.length; ++i) {
    await runTest("Hello world", URIs[i]);
    await runTest(a, URIs[i]);
  }
});