tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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test_weakRefs_collected_wrapper.html (1617B)


      1 <!DOCTYPE HTML>
      2 <html>
      3  <head>
      4    <meta charset="utf-8">
      5    <title>Test WeakRefs with DOM wrappers that get cycle collected</title>
      6    <script src="/tests/SimpleTest/SimpleTest.js"></script>
      7    <script type="application/javascript">
      8      let weakrefs = [];
      9 
     10      function go() {
     11        SimpleTest.waitForExplicitFinish();
     12 
     13        // 1. nsISupports-derived object.
     14        let doc = document.implementation.createHTMLDocument();
     15        weakrefs.push(new WeakRef(doc));
     16 
     17        // 2. non-nsISupports-derived object.
     18        let buffer = new AudioBuffer({length: 1, sampleRate: 8000});
     19        weakrefs.push(new WeakRef(buffer));
     20 
     21        // 3. nsISupports non-wrapper-cached object.
     22        let image = new ImageData(1, 1);
     23        weakrefs.push(new WeakRef(image));
     24 
     25        // 4. non-nsISupports non-wrapper-cached object.
     26        let iterator = document.fonts.values();
     27        weakrefs.push(new WeakRef(iterator));
     28 
     29        for (let wr of weakrefs) {
     30          isnot(wr.deref(), undefined, "Check that live wrapper is returned");
     31        }
     32 
     33        // setTimeout will call its callback in a new task.
     34        setTimeout(task2, 0);
     35      }
     36 
     37      function task2() {
     38        // Trigger a GC and CC to collect the DOM objects, but no GC to
     39        // collect the wrappers.
     40        SpecialPowers.DOMWindowUtils.garbageCollect();
     41        SpecialPowers.DOMWindowUtils.cycleCollect();
     42 
     43        for (let wr of weakrefs) {
     44          is(wr.deref(), undefined, "Check that stale wrapper is not exposed");
     45        }
     46 
     47        SimpleTest.finish();
     48      }
     49    </script>
     50  </head>
     51  <body onload="go()"></body>
     52 </html>