test_js_weak_references.js

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/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* See https://bugzilla.mozilla.org/show_bug.cgi?id=317304 */

function run_test()

  // Bug 712649: Calling getWeakReference(null) should work.

  try {

    var nullWeak = Cu.getWeakReference(null);

    Assert.ok(nullWeak.get() === null);

  } catch (e) {

    Assert.ok(false);

  var obj = { num: 5, str: 'foo' };

  var weak = Cu.getWeakReference(obj);

  Assert.ok(weak.get() === obj);

  Assert.ok(weak.get().num == 5);

  Assert.ok(weak.get().str == 'foo');

  // Force garbage collection

  Cu.forceGC();

  // obj still references the object, so it should still be accessible via weak

  Assert.ok(weak.get() === obj);

  Assert.ok(weak.get().num == 5);

  Assert.ok(weak.get().str == 'foo');

  // Clear obj's reference to the object and force garbage collection. To make

  // sure that there are no instances of obj stored in the registers or on the

  // native stack and the conservative GC would not find it we force the same

  // code paths that we used for the initial allocation.

  obj = { num: 6, str: 'foo2' };

  var weak2 = Cu.getWeakReference(obj);

  Assert.ok(weak2.get() === obj);

  Cu.forceGC();

  // The object should have been garbage collected and so should no longer be

  // accessible via weak

  Assert.ok(weak.get() === null);