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// Shared helpers for the media-playback-while-not-visible permission policy
// tests. The same helpers drive both the same-origin and cross-origin
// scenarios; the only difference between the two is the origin of the iframe
// that hosts the AudioContext, which is passed in as `base` (a URL prefix to
// the resources/ directory on the desired origin).
// Returns a promise that resolves when the iframe's AudioContext emits a
// 'statechange' event. The promise resolves with the new state of the
// AudioContext, or with 'no state change' if no event fires within `timeout`
// milliseconds. The event listener is removed once the promise settles.
// Callers that expect no state change can pass a shorter `timeout` to avoid
// waiting the full default duration on every negative assertion.
function expectIframeAudioContextStateChangeEvent(test, timeout = 2000) {
return new Promise(resolve => {
function expectStateChangeEvent(event) {
if (event.data.operation !== 'statechange') {
return;
}
window.removeEventListener('message', expectStateChangeEvent);
resolve(event.data.value);
}
window.addEventListener('message', expectStateChangeEvent);
test.step_timeout(() => {
window.removeEventListener('message', expectStateChangeEvent);
resolve('no state change');
}, timeout);
});
}
// Sends a message to the iframe to query the state of the AudioContext and
// returns a promise that resolves with the state of the AudioContext. The
// event listener is removed after the promise resolves.
function queryAudioContextState(iframe) {
return new Promise(resolve => {
window.addEventListener(
'message', function expectStateQueryResponse(event) {
if (event.data.operation !== 'getState') {
return;
}
window.removeEventListener('message', expectStateQueryResponse);
resolve(event.data.value);
});
iframe.contentWindow.postMessage('getState', '*');
});
}
// Sends a message to the iframe with a command that should be performed on
// the AudioContext. Returns a promise that resolves when the operation is
// completed. The event listener is removed after the promise resolves.
function sendCommandToAudioContext(iframe, command) {
return new Promise(resolve => {
window.addEventListener('message', function expectCommandResponse(event) {
if (event.data.operation !== command) {
return;
}
window.removeEventListener('message', expectCommandResponse);
resolve(event.data.value);
});
iframe.contentWindow.postMessage(command, '*');
});
}
// Drives the iframe's AudioContext into `expected_initial_state` ('running' or
// 'suspended'). Returns a promise that resolves with the resulting state.
async function setUpIframeAudioContextInitialState(t, iframe,
expected_initial_state) {
const initial_state = await queryAudioContextState(iframe);
if (initial_state === expected_initial_state || initial_state === 'closed') {
return initial_state;
}
const statechange_promise = expectIframeAudioContextStateChangeEvent(t);
if (expected_initial_state === 'running') {
await sendCommandToAudioContext(iframe, 'resume');
} else if (expected_initial_state === 'suspended') {
await sendCommandToAudioContext(iframe, 'suspend');
}
return statechange_promise;
}
function hideFrame(iframe, type) {
if (type === 'display') {
iframe.style.setProperty('display', 'none');
} else if (type === 'visibility') {
iframe.style.setProperty('visibility', 'hidden');
} else if (type === 'zero-size') {
iframe.style.setProperty('width', '0');
iframe.style.setProperty('height', '0');
}
}
function showFrame(iframe, type) {
if (type === 'display') {
iframe.style.setProperty('display', 'block');
} else if (type === 'visibility') {
iframe.style.setProperty('visibility', 'visible');
} else if (type === 'zero-size') {
iframe.style.removeProperty('width');
iframe.style.removeProperty('height');
}
}
// Creates an iframe that hosts an AudioContext and waits for it to reach the
// 'running' state. `base` is the URL prefix (including trailing slash) to the
// resources/ directory on the desired origin; using the alternate-host base
// produces a genuine cross-origin (out-of-process) iframe. If `frameType` is
// 'nested', an intermediate iframe is inserted between the test page and the
// AudioContext frame, so the test page and the AudioContext frame are always
// separated by at least one frame boundary on origin `base`.
async function createIframe(t, frameType, base) {
if (document.readyState !== 'complete') {
await new Promise(resolve => window.addEventListener('load', resolve));
}
const running_state_transition_promise =
expectIframeAudioContextStateChangeEvent(t);
const iframe = document.createElement('iframe');
if (frameType === 'nested') {
iframe.id = 'intermediate-frame';
iframe.src = base + 'intermediate-frame.html';
} else {
iframe.id = 'audio-context-frame';
iframe.allow = 'media-playback-while-not-visible \'none\'; autoplay *';
iframe.src = base + 'audiocontext-frame.html';
}
document.body.appendChild(iframe);
await new Promise(resolve => iframe.addEventListener('load', resolve));
t.add_cleanup(() => iframe.remove());
assert_equals(await running_state_transition_promise, 'running');
return iframe;
}