test_getUserMedia_GC_MediaStream.html

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<head>

  <script type="application/javascript" src="mediaStreamPlayback.js"></script>

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<pre id="test">

<script type="application/javascript">

  "use strict";

  createHTML({

    title: "MediaStreams can be garbage collected",

    bug: "1407542"

});

  let SpecialStream = SpecialPowers.wrap(MediaStream);

  async function testGC(stream, numCopies, copy) {

    let startStreams = await SpecialStream.countUnderlyingStreams();

    let copies = new Array(numCopies).fill(0).map(() => copy(stream));

    ok(await SpecialStream.countUnderlyingStreams() > startStreams,

        "MediaStreamTrack constructor creates more underlying streams");

    copies = [];

    await new Promise(r => SpecialPowers.exactGC(r));

    is(await SpecialStream.countUnderlyingStreams(), startStreams,

       "MediaStreamTracks should have been collected");

  runTest(async () => {

    let gUMStream = await getUserMedia({video: true});

    info("Testing GC of track-array constructor with cloned tracks");

    await testGC(gUMStream, 10, s => new MediaStream(s.getTracks().map(t => t.clone())));

    info("Testing GC of empty constructor plus addTrack with cloned tracks");

    await testGC(gUMStream, 10, s => {

      let s2 = new MediaStream();

      s.getTracks().forEach(t => s2.addTrack(t.clone()));

      return s2;

});

    info("Testing GC of cloned stream");

    await testGC(gUMStream, 10, s => s.clone());

    info("Testing GC of gUM stream");

    gUMStream = null;

    await new Promise(r => SpecialPowers.exactGC(r));

    is(await SpecialStream.countUnderlyingStreams(), 0,

       "Original gUM stream should be collectable");

});

</script>

</pre>

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