Bug 1598114 - Compute the values for each AudioParamTimeline directly into the Float32Arrays and pass the object to `process`. r=karlt

Differential Revision: https://phabricator.services.mozilla.com/D63356

--HG--
extra : moz-landing-system : lando

dom/media/webaudio/AudioWorkletNode.cpp

@@ -346,7 +346,7 @@ bool WorkletNodeEngine::CallProcess(AudioNodeTrack* aTrack, JSContext* aCx,
   }
   argv[0].setObject(*mInputs.mJSArray);
   argv[1].setObject(*mOutputs.mJSArray);
-  // TODO: argv[2].setObject() for parameters.
+  argv[2].setObject(*mParameters.mJSObject);
   JS::Rooted<JS::Value> rval(aCx);
   if (!JS::Call(aCx, mProcessor, aCallable, argv, &rval)) {
     return false;
@@ -457,6 +457,35 @@ void WorkletNodeEngine::ProcessBlocksOnPorts(AudioNodeTrack* aTrack,
     }
   }
 
+  TrackTime tick = mDestination->GraphTimeToTrackTime(aFrom);
+  // Compute and copy parameter values to JS objects.
+  for (size_t i = 0; i < mParamTimelines.Length(); ++i) {
+    const auto& float32Arrays = mParameters.mFloat32Arrays[i];
+    uint32_t length = JS_GetTypedArrayLength(float32Arrays);
+
+    // If the Float32Array that is supposed to hold the values for a particular
+    // AudioParam has been detached, error out. This is being worked on in
+    // https://github.com/WebAudio/web-audio-api/issues/1933 and
+    // https://bugzilla.mozilla.org/show_bug.cgi?id=1619486
+    if (length != WEBAUDIO_BLOCK_SIZE) {
+      SendProcessorError();
+      ProduceSilence(aTrack, aOutput);
+      return;
+    }
+    JS::AutoCheckCannotGC nogc;
+    bool isShared;
+    float* dest = JS_GetFloat32ArrayData(float32Arrays, &isShared, nogc);
+    MOZ_ASSERT(!isShared);  // Was created as unshared
+
+    size_t frames =
+        mParamTimelines[i].mTimeline.HasSimpleValue() ? 1 : WEBAUDIO_BLOCK_SIZE;
+    mParamTimelines[i].mTimeline.GetValuesAtTime(tick, dest, frames);
+    // https://bugzilla.mozilla.org/show_bug.cgi?id=1616599
+    if (frames == 1) {
+      std::fill_n(dest + 1, WEBAUDIO_BLOCK_SIZE - 1, dest[0]);
+    }
+  }
+
   if (!CallProcess(aTrack, cx, process)) {
     // An exception occurred.
     SendProcessorError();