Source code
Revision control
Copy as Markdown
Other Tools
Test Info:
- Manifest: dom/base/test/browser.toml
// A <link rel="modulepreload"> whose module is served from the in-memory
// navigation cache (SharedScriptCache) is fetched without opening a channel,
// just like a module already present in the module map. Such a preload must
// still fire a "load" event rather than a spurious "error".
const MODULE_URL = BASE_URL + "file_js_cache_small.js";
add_task(async function () {
await SpecialPowers.pushPrefEnv({
set: [
["dom.expose_test_interfaces", true],
["dom.script_loader.bytecode_cache.enabled", true],
["dom.script_loader.bytecode_cache.strategy", 0],
["dom.script_loader.experimental.navigation_cache", true],
["dom.script_loader.disk_cache_delay_ms", 0],
],
});
await BrowserTestUtils.withNewTab(BASE_URL + "empty.html", async browser => {
const tab = gBrowser.getTabForBrowser(browser);
ChromeUtils.clearResourceCache();
Services.cache2.clear();
// Load the module normally so its stencil is stored in the process-wide
// SharedScriptCache. Wait for "memorycache:saved" so the cache is populated
// before we reload.
await SpecialPowers.spawn(browser, [MODULE_URL], async url => {
const saved = new Promise(resolve => {
const obs = (subject, topic, data) => {
const params = {};
for (const line of data.split("\n")) {
const i = line.indexOf(":");
params[line.slice(0, i)] = line.slice(i + 1);
}
if (params.event === "memorycache:saved" && params.url === url) {
Services.obs.removeObserver(obs, "ScriptLoaderTest");
resolve();
}
};
Services.obs.addObserver(obs, "ScriptLoaderTest");
});
const script = content.document.createElement("script");
script.type = "module";
script.crossOrigin = "";
script.src = url;
content.document.body.appendChild(script);
await saved;
});
// Reload to get a fresh document (empty module map) while the
// SharedScriptCache persists across the same-origin navigation.
await BrowserTestUtils.reloadTab(tab);
// In the fresh document, a <link rel="modulepreload"> for the same URL is
// served from the memory cache (no channel opened). It must fire "load",
// and we assert the memory-cache path was actually taken.
const result = await SpecialPowers.spawn(
browser,
[MODULE_URL],
async url => {
let usedMemoryCache = false;
const obs = (subject, topic, data) => {
const params = {};
for (const line of data.split("\n")) {
const i = line.indexOf(":");
params[line.slice(0, i)] = line.slice(i + 1);
}
if (params.event === "load:memorycache" && params.url === url) {
usedMemoryCache = true;
}
};
Services.obs.addObserver(obs, "ScriptLoaderTest");
const link = content.document.createElement("link");
link.rel = "modulepreload";
link.as = "script";
link.crossOrigin = "";
link.href = url;
const event = await new Promise(resolve => {
link.addEventListener("load", () => resolve("load"), { once: true });
link.addEventListener("error", () => resolve("error"), {
once: true,
});
content.document.head.appendChild(link);
});
Services.obs.removeObserver(obs, "ScriptLoaderTest");
return { event, usedMemoryCache };
}
);
is(
result.event,
"load",
"modulepreload served from memory cache fires load"
);
ok(
result.usedMemoryCache,
"the modulepreload was served from the in-memory navigation cache"
);
});
await SpecialPowers.popPrefEnv();
});