speculation-rules/prerender/storage-foundation.https.html

<!DOCTYPE html>
<title>Same-origin prerendering can access Storage Foundation API</title>
<meta name="timeout" content="long">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/utils.js"></script>
<script src="resources/utils.js"></script>
<body>
<script>

setup(() => assertSpeculationRulesIsSupported());

const expectedReadBuffer = [65, 66, 67, 68];

async function writeToFile() {
  let f = await storageFoundation.open('test_file');
  const writeBuffer = new Uint8Array(4);
  writeBuffer.set(expectedReadBuffer);

  await storageFoundation.requestCapacity(4);

  const {writtenBytes} = await f.write(writeBuffer, 0);
  await f.flush();
  await f.close();
  return writtenBytes == 4;
}

async function readFromFile() {
  let f = await storageFoundation.open('test_file');
  const {buffer, readBytes} = await f.read(new Uint8Array(4), 0);
  await f.close();
  return buffer;
}

promise_test(async t => {
  const uid = token();
  const bc = new PrerenderChannel('prerender-channel', uid);

  const gotMessage = new Promise(resolve => {
    bc.addEventListener('message', e => {
      resolve(e.data);
    }, {
      once: true
    });
  });

  const writeResult = await writeToFile();
  assert_true(
    writeResult,
    'primary page should be able to write to storage foundation API.');

  // Start prerendering a page that attempts to access storage foundation API.
  startPrerendering(`resources/storage-foundation-access.https.html`);
  const result = await gotMessage;

  assert_array_equals(
    result.readBuffer, expectedReadBuffer,
    'prerendering page should be able to read from storage foundation API');

  const readBufferWrittenByPrerender = await readFromFile();
  assert_array_equals(
    result.writtenBuffer, readBufferWrittenByPrerender,
    'prerendering page should be able to write to storage foundation API');

  await storageFoundation.delete('test_file');
}, 'prerendering page should be able to access storage foundation API');

</script>
</body>