Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 84 insertions, 0 deletions

diff --git a/dom/events/test/event_leak_utils.js b/dom/events/test/event_leak_utils.js
new file mode 100644
index 0000000000..86b26a4136
--- /dev/null
+++ b/dom/events/test/event_leak_utils.js
@@ -0,0 +1,84 @@
+// Any copyright is dedicated to the Public Domain.
+// http://creativecommons.org/publicdomain/zero/1.0/
+"use strict";
+
+// This function runs a number of tests where:
+//
+//  1. An iframe is created
+//  2. The target callback is executed with the iframe's contentWindow as
+//     an argument.
+//  3. The iframe is destroyed and GC is forced.
+//  4. Verifies that the iframe's contentWindow has been GC'd.
+//
+// Different ways of destroying the iframe are checked.  Simple
+// remove(), destruction via bfcache, or replacement by document.open().
+//
+// Please pass a target callback that exercises the API under
+// test using the given window.  The callback should try to leave the
+// API active to increase the liklihood of provoking an API.  Any activity
+// should be canceled by the destruction of the window.
+async function checkForEventListenerLeaks(name, target) {
+  // Test if we leak in the case where we do nothing special to
+  // the frame before removing it from the DOM.
+  await _eventListenerLeakStep(target, `${name} default`);
+
+  // Test the case where we navigate the frame before removing it
+  // from the DOM so that the window using the target API ends up
+  // in bfcache.
+  await _eventListenerLeakStep(target, `${name} bfcache`, frame => {
+    frame.src = "about:blank";
+    return new Promise(resolve => (frame.onload = resolve));
+  });
+
+  // Test the case where we document.open() the frame before removing
+  // it from the DOM so that the window using the target API ends
+  // up getting replaced.
+  await _eventListenerLeakStep(target, `${name} document.open()`, frame => {
+    frame.contentDocument.open();
+    frame.contentDocument.close();
+  });
+}
+
+// ----------------
+// Internal helpers
+// ----------------
+
+// Utility function to create a loaded iframe.
+async function _withFrame(doc, url) {
+  let frame = doc.createElement("iframe");
+  frame.src = url;
+  doc.body.appendChild(frame);
+  await new Promise(resolve => (frame.onload = resolve));
+  return frame;
+}
+
+// This function defines the basic form of the test cases.  We create an
+// iframe, execute the target callback to manipulate the DOM, remove the frame
+// from the DOM, and then check to see if the frame was GC'd.  The caller
+// may optionally pass in a callback that will be executed with the
+// frame as an argument before removing it from the DOM.
+async function _eventListenerLeakStep(target, name, extra) {
+  let frame = await _withFrame(document, "empty.html");
+
+  await target(frame.contentWindow);
+
+  let weakRef = SpecialPowers.Cu.getWeakReference(frame.contentWindow);
+  ok(weakRef.get(), `should be able to create a weak reference - ${name}`);
+
+  if (extra) {
+    await extra(frame);
+  }
+
+  frame.remove();
+  frame = null;
+
+  // Perform many GC's to avoid intermittent delayed collection.
+  await new Promise(resolve => SpecialPowers.exactGC(resolve));
+  await new Promise(resolve => SpecialPowers.exactGC(resolve));
+  await new Promise(resolve => SpecialPowers.exactGC(resolve));
+
+  ok(
+    !weakRef.get(),
+    `iframe content window should be garbage collected - ${name}`
+  );
+}