<!DOCTYPE html>
<meta charset="utf-8">
<title>Structured cloning of SharedArrayBuffers: BroadcastChannel within the same agent cluster</title>
<link rel="help" href="https://html.spec.whatwg.org/multipage/#structuredserialize">
<link rel="help" href="https://html.spec.whatwg.org/multipage/#broadcasting-to-other-browsing-contexts">
<link rel="author" title="Domenic Denicola" href="mailto:d@domenic.me">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/utils.js"></script> <!-- Use token() to allow running tests in parallel -->

<div id="log"></div>

<script>
"use strict";

promise_test(t => {
  const channelName = token();
  return Promise.all([
    createIFrame(`resources/broadcastchannel-iframe.html?channel=${channelName}&index=0`),
    createIFrame(`resources/broadcastchannel-iframe.html?channel=${channelName}&index=1`),
    createIFrame(`resources/broadcastchannel-iframe.html?channel=${channelName}&index=2`)
  ]).then(() => {
    const sab = new SharedArrayBuffer(3);
    const view = new Uint8Array(sab);
    const channel = new BroadcastChannel(channelName);

    return new Promise(resolve => {
      let soFar = 0;
      channel.onmessage = t.step_func(({ data: { i } }) => {
        assert_in_array(i, [0, 1, 2], "Any message events must come from expected sources");
        ++soFar;

        if (soFar === 3) {
          assert_equals(view[0], 1, "The first iframe must have set view[0] to 1");
          assert_equals(view[1], 2, "The second iframe must have set view[1] to 2");
          assert_equals(view[2], 3, "The third iframe must have set view[2] to 3");
          resolve();
        }
      });

      channel.postMessage({ sab });
    });
  });
});

function createIFrame(src) {
  return new Promise((resolve, reject) => {
    const iframe = document.createElement("iframe");
    iframe.src = src;
    iframe.onload = () => resolve(iframe);
    iframe.onerror = () => reject(`iframe with URL ${src} failed to load`);
    document.body.appendChild(iframe);
  });
}
</script>
