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<head>
  <title>Test tail time lifetime of DelayNode after input finishes and new input added</title>
  <script src="/tests/SimpleTest/SimpleTest.js"></script>
  <script type="text/javascript" src="webaudio.js"></script>
  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
</head>
<body>
<pre id="test">
<script class="testbody" type="text/javascript">

SimpleTest.waitForExplicitFinish();

// The buffer source will start on a block boundary, so keeping the signal
// within one block ensures that it will not cross AudioProcessingEvent buffer
// boundaries.
const signalLength = 128;
const bufferSize = 1024;
// Delay should be long enough to allow CC to run
var delayBufferCount = 50;
var delayBufferOffset;
const delayLength = delayBufferCount * bufferSize;

var phase = "initial";
var sourceCount = 0;
var delayCount = 0;
var oscillator;
var delay;
var source;

function applySignal(buffer, offset) {
  for (var i = 0; i < signalLength; ++i) {
    buffer.getChannelData(0)[offset + i] = Math.cos(Math.PI * i / signalLength);
  }
}

function bufferIsSilent(buffer, out) {
  for (var i = 0; i < buffer.length; ++i) {
    if (buffer.getChannelData(0)[i] != 0) {
      if (out) {
        out.soundOffset = i;
      }
      return false;
    }
  }
  return true;
}

function onDelayOutput(e) {
  switch(phase) {

  case "initial":
    // Wait for oscillator sound to exit delay
    if (bufferIsSilent(e.inputBuffer))
      break;

    phase = "played oscillator";
    break;

  case "played oscillator":
    // First tail time has expired.  Start second source and remove references
    // to the delay and connected second source.
    oscillator.disconnect();
    source.connect(delay);
    source.start();
    source = null;
    delay = null;
    phase = "started second source";
    break;

  case "second tail time":
    if (delayCount == delayBufferCount) {
      var ctx = e.target.context;
      var expected = ctx.createBuffer(1, bufferSize, ctx.sampleRate);
      applySignal(expected, delayBufferOffset);
      compareBuffers(e.inputBuffer, expected);
      e.target.onaudioprocess = null;
      SimpleTest.finish();
    }
  }

  delayCount++;
}

function onSourceOutput(e) {
  switch(phase) {
  case "started second source":
    var out = {};
    if (!bufferIsSilent(e.inputBuffer, out)) {
      delayBufferCount += sourceCount;
      delayBufferOffset = out.soundOffset;
      phase = "played second source";
    }
    break;
  case "played second source":
    SpecialPowers.forceGC();
    SpecialPowers.forceCC();
    phase = "second tail time";
    e.target.onaudioprocess = null;
  }

  sourceCount++;
}

function startTest() {
  var ctx = new AudioContext();
  var delayDuration = delayLength / ctx.sampleRate;
  delay = ctx.createDelay(delayDuration);
  delay.delayTime.value = delayDuration;
  var processor1 = ctx.createScriptProcessor(bufferSize, 1, 0);
  delay.connect(processor1);
  processor1.onaudioprocess = onDelayOutput;

  // Signal to trigger initial tail time reference
  oscillator = ctx.createOscillator();
  oscillator.start(0);
  oscillator.stop(100/ctx.sampleRate);
  oscillator.connect(delay);

  // Short signal, not started yet, with a ScriptProcessor to detect when it
  // starts.  It should finish before garbage collection.
  var buffer = ctx.createBuffer(1, signalLength, ctx.sampleRate);
  applySignal(buffer, 0);
  source = ctx.createBufferSource();
  source.buffer = buffer;
  var processor2 = ctx.createScriptProcessor(bufferSize, 1, 0);
  source.connect(processor2);
  processor2.onaudioprocess = onSourceOutput;
};

startTest();
</script>
</pre>
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