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<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>Scoped custom element registries are collected with their nodes</title>
<script src="/tests/SimpleTest/SimpleTest.js"></script>
<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
</head>
<body>
<script>
"use strict";
async function forceGC() {
for (let i = 0; i < 3; i++) {
await new Promise(resolve => setTimeout(resolve, 0));
await new Promise(resolve => SpecialPowers.exactGC(resolve));
}
}
// An expando preserves the registry's wrapper, so the wrapper stays alive
// exactly as long as the native registry does and the weak reference tracks
// the registry itself rather than a wrapper the GC is free to drop.
function weakRegistry(registry) {
registry.__preserveWrapper = true;
return SpecialPowers.Cu.getWeakReference(registry);
}
add_setup(async function () {
await SpecialPowers.pushPrefEnv({
set: [["dom.scoped-custom-element-registries.enabled", true]],
});
});
add_task(async function weak_reference_sanity() {
let registry = new CustomElementRegistry();
let weak = weakRegistry(registry);
await forceGC();
ok(weak.get(), "registry stays alive while referenced");
registry = null;
await forceGC();
ok(!weak.get(), "registry is collected once unreferenced");
});
add_task(async function document_initialize() {
let weak = (() => {
let registry = new CustomElementRegistry();
registry.initialize(document.implementation.createHTMLDocument("x"));
return weakRegistry(registry);
})();
await forceGC();
ok(!weak.get(), "registry of an initialized document is collected with it");
});
add_task(async function shadow_root_registry() {
let weak = (() => {
let registry = new CustomElementRegistry();
let host = document.createElement("div");
// The constructor closes over the host: registry -> constructor -> host
// -> shadow root -> registry is a cycle only the cycle collector can
// break, and only if it can see the shadow root's edge to the registry.
registry.define("x-shadow-cycle", class extends HTMLElement {
constructor() {
super();
this.host = host;
}
});
host.attachShadow({ mode: "open", customElementRegistry: registry });
return weakRegistry(registry);
})();
await forceGC();
ok(!weak.get(), "registry of a shadow root is collected with its host");
});
add_task(async function element_registry() {
let weak = (() => {
let registry = new CustomElementRegistry();
let element = document.createElement("div", {
customElementRegistry: registry,
});
registry.define("x-element-cycle", class extends HTMLElement {
constructor() {
super();
this.element = element;
}
});
return weakRegistry(registry);
})();
await forceGC();
ok(!weak.get(), "registry of an element is collected with the element");
});
</script>
</body>
</html>