Rob Wu
7da0fc6819
The _startIdleDispatch uses `ChromeUtils.idleDispatch`, which may keep the DeferredTask instance alive longer than necessary, which in turn prevents the task callback and its closure from being garbage collected. This has resulted in observed window leaks at the end of test runs. To prevent this issue from happening, we automatically detect whether the callback belongs to a window, and if so, tie the (idle) timers to that window, so that the callbacks are immediately released when that window unloads. We also clear the callback reference when `finalize()` is called, so that the task callback and its closure are not kept alive for longer than necessary (upon unload), even if the window is still alive. Differential Revision: https://phabricator.services.mozilla.com/D284782
65 lines
2.1 KiB
JavaScript
65 lines
2.1 KiB
JavaScript
/* Any copyright is dedicated to the Public Domain.
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http://creativecommons.org/publicdomain/zero/1.0/ */
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async function promiseMessageEvent(window) {
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let event = await new Promise(resolve => {
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window.addEventListener("message", resolve, { once: true });
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});
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return event.data;
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}
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add_task(async function test_deferred_task_in_window() {
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const windowlessBrowser = Services.appShell.createWindowlessBrowser(true);
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const { document } = windowlessBrowser;
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const messagePromise = promiseMessageEvent(document.defaultView);
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let script = document.createElement("script");
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script.src = "resource://test/test_DeferredTask_window/test_basics.js";
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document.documentElement.append(script);
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Assert.equal(
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await messagePromise,
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"arm_and_wait_should_run",
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"Basic operations of DeferredTask should work in a window context"
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);
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windowlessBrowser.close();
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});
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add_task(async function test_deferred_task_past_unload() {
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const windowlessBrowser = Services.appShell.createWindowlessBrowser(true);
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const { document } = windowlessBrowser;
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const results = [];
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await new Promise(resolve => {
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let iframe = document.createElement("iframe");
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document.documentElement.append(iframe);
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iframe.contentWindow.reportTestResult = msg => results.push(msg);
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let script = iframe.contentDocument.createElement("script");
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script.src = "resource://test/test_DeferredTask_window/test_iframe.js";
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script.onload = () => resolve();
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iframe.contentDocument.documentElement.append(script);
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});
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// The DeferredTask in test_iframe.js have short deadlines. Wait a little bit
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// more to see if the script would run and notify us.
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await new Promise(r => document.defaultView.setTimeout(r, 100));
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// Sanity check: the iframe was removed.
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Assert.equal(document.defaultView.frames.length, 0, "Frame was removed");
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// As a sanity check we verify that the iframe can send "removing_iframe",
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// but other than that we should not get any other message.
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Assert.deepEqual(
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results,
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["removing_iframe"],
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"DeferredTask should not run after the window/iframe unloads"
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);
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windowlessBrowser.close();
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});
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