Adding upstream version 115.8.0esr.upstream/115.8.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 896 insertions, 0 deletions

diff --git a/dom/media/webaudio/AudioWorkletNode.cpp b/dom/media/webaudio/AudioWorkletNode.cpp
new file mode 100644
index 0000000000..2b8afade3c
--- /dev/null
+++ b/dom/media/webaudio/AudioWorkletNode.cpp
@@ -0,0 +1,896 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 https://mozilla.org/MPL/2.0/. */
+
+#include "AudioWorkletNode.h"
+
+#include "AudioNodeEngine.h"
+#include "AudioParamMap.h"
+#include "AudioWorkletImpl.h"
+#include "js/Array.h"  // JS::{Get,Set}ArrayLength, JS::NewArrayLength
+#include "js/CallAndConstruct.h"  // JS::Call, JS::IsCallable
+#include "js/Exception.h"
+#include "js/experimental/TypedData.h"  // JS_NewFloat32Array, JS_GetFloat32ArrayData, JS_GetTypedArrayLength, JS_GetArrayBufferViewBuffer
+#include "js/PropertyAndElement.h"  // JS_DefineElement, JS_DefineUCProperty, JS_GetProperty
+#include "mozilla/dom/AudioWorkletNodeBinding.h"
+#include "mozilla/dom/AudioParamMapBinding.h"
+#include "mozilla/dom/AutoEntryScript.h"
+#include "mozilla/dom/RootedDictionary.h"
+#include "mozilla/dom/ErrorEvent.h"
+#include "mozilla/dom/Worklet.h"
+#include "nsIScriptGlobalObject.h"
+#include "AudioParam.h"
+#include "AudioDestinationNode.h"
+#include "mozilla/dom/MessageChannel.h"
+#include "mozilla/dom/MessagePort.h"
+#include "mozilla/ScopeExit.h"
+#include "nsReadableUtils.h"
+#include "mozilla/Span.h"
+#include "PlayingRefChangeHandler.h"
+#include "nsPrintfCString.h"
+#include "Tracing.h"
+
+namespace mozilla::dom {
+
+NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED_0(AudioWorkletNode, AudioNode)
+NS_IMPL_CYCLE_COLLECTION_INHERITED(AudioWorkletNode, AudioNode, mPort,
+                                   mParameters)
+
+struct NamedAudioParamTimeline {
+  explicit NamedAudioParamTimeline(const AudioParamDescriptor& aParamDescriptor)
+      : mName(aParamDescriptor.mName),
+        mTimeline(aParamDescriptor.mDefaultValue) {}
+  const nsString mName;
+  AudioParamTimeline mTimeline;
+};
+
+struct ProcessorErrorDetails {
+  ProcessorErrorDetails() : mLineno(0), mColno(0) {}
+  unsigned mLineno;
+  unsigned mColno;
+  nsString mFilename;
+  nsString mMessage;
+};
+
+class WorkletNodeEngine final : public AudioNodeEngine {
+ public:
+  WorkletNodeEngine(AudioWorkletNode* aNode,
+                    AudioDestinationNode* aDestinationNode,
+                    nsTArray<NamedAudioParamTimeline>&& aParamTimelines,
+                    const Optional<Sequence<uint32_t>>& aOutputChannelCount)
+      : AudioNodeEngine(aNode),
+        mDestination(aDestinationNode->Track()),
+        mParamTimelines(std::move(aParamTimelines)) {
+    if (aOutputChannelCount.WasPassed()) {
+      mOutputChannelCount = aOutputChannelCount.Value();
+    }
+  }
+
+  MOZ_CAN_RUN_SCRIPT
+  void ConstructProcessor(AudioWorkletImpl* aWorkletImpl,
+                          const nsAString& aName,
+                          NotNull<StructuredCloneHolder*> aSerializedOptions,
+                          UniqueMessagePortId& aPortIdentifier,
+                          AudioNodeTrack* aTrack);
+
+  void RecvTimelineEvent(uint32_t aIndex, AudioTimelineEvent& aEvent) override {
+    MOZ_ASSERT(mDestination);
+    WebAudioUtils::ConvertAudioTimelineEventToTicks(aEvent, mDestination);
+
+    if (aIndex < mParamTimelines.Length()) {
+      mParamTimelines[aIndex].mTimeline.InsertEvent<int64_t>(aEvent);
+    } else {
+      NS_ERROR("Bad WorkletNodeEngine timeline event index");
+    }
+  }
+
+  void ProcessBlock(AudioNodeTrack* aTrack, GraphTime aFrom,
+                    const AudioBlock& aInput, AudioBlock* aOutput,
+                    bool* aFinished) override {
+    MOZ_ASSERT(InputCount() <= 1);
+    MOZ_ASSERT(OutputCount() <= 1);
+    TRACE("WorkletNodeEngine::ProcessBlock");
+    ProcessBlocksOnPorts(aTrack, aFrom, Span(&aInput, InputCount()),
+                         Span(aOutput, OutputCount()), aFinished);
+  }
+
+  void ProcessBlocksOnPorts(AudioNodeTrack* aTrack, GraphTime aFrom,
+                            Span<const AudioBlock> aInput,
+                            Span<AudioBlock> aOutput, bool* aFinished) override;
+
+  void OnGraphThreadDone() override { ReleaseJSResources(); }
+
+  bool IsActive() const override { return mKeepEngineActive; }
+
+  // Vector<T> supports non-memmovable types such as PersistentRooted
+  // (without any need to jump through hoops like
+  // MOZ_DECLARE_RELOCATE_USING_MOVE_CONSTRUCTOR_FOR_TEMPLATE for nsTArray).
+  // PersistentRooted is used because these AudioWorkletGlobalScope scope
+  // objects may be kept alive as long as the AudioWorkletNode in the
+  // main-thread global.
+  struct Channels {
+    Vector<JS::PersistentRooted<JSObject*>, GUESS_AUDIO_CHANNELS>
+        mFloat32Arrays;
+    JS::PersistentRooted<JSObject*> mJSArray;
+    // For SetArrayElements():
+    operator JS::Handle<JSObject*>() const { return mJSArray; }
+  };
+  struct Ports {
+    Vector<Channels, 1> mPorts;
+    JS::PersistentRooted<JSObject*> mJSArray;
+  };
+  struct ParameterValues {
+    Vector<JS::PersistentRooted<JSObject*>> mFloat32Arrays;
+    JS::PersistentRooted<JSObject*> mJSObject;
+  };
+
+ private:
+  size_t ParameterCount() { return mParamTimelines.Length(); }
+  void SendProcessorError(AudioNodeTrack* aTrack, JSContext* aCx);
+  bool CallProcess(AudioNodeTrack* aTrack, JSContext* aCx,
+                   JS::Handle<JS::Value> aCallable);
+  void ProduceSilence(AudioNodeTrack* aTrack, Span<AudioBlock> aOutput);
+  void SendErrorToMainThread(AudioNodeTrack* aTrack,
+                             const ProcessorErrorDetails& aDetails);
+
+  void ReleaseJSResources() {
+    mInputs.mPorts.clearAndFree();
+    mOutputs.mPorts.clearAndFree();
+    mParameters.mFloat32Arrays.clearAndFree();
+    mInputs.mJSArray.reset();
+    mOutputs.mJSArray.reset();
+    mParameters.mJSObject.reset();
+    mGlobal = nullptr;
+    // This is equivalent to setting [[callable process]] to false.
+    mProcessor.reset();
+  }
+
+  nsCString mProcessorName;
+  RefPtr<AudioNodeTrack> mDestination;
+  nsTArray<uint32_t> mOutputChannelCount;
+  nsTArray<NamedAudioParamTimeline> mParamTimelines;
+  // The AudioWorkletGlobalScope-associated objects referenced from
+  // WorkletNodeEngine are typically kept alive as long as the
+  // AudioWorkletNode in the main-thread global.  The objects must be released
+  // on the rendering thread, which usually happens simply because
+  // AudioWorkletNode is such that the last AudioNodeTrack reference is
+  // released by the MTG.  That occurs on the rendering thread except during
+  // process shutdown, in which case NotifyForcedShutdown() is called on the
+  // rendering thread.
+  //
+  // mInputs, mOutputs and mParameters keep references to all objects passed to
+  // process(), for reuse of the same objects.  The JS objects are all in the
+  // compartment of the realm of mGlobal.  Properties on the objects may be
+  // replaced by script, so don't assume that getting indexed properties on the
+  // JS arrays will return the same objects.  Only objects and buffers created
+  // by the implementation are modified or read by the implementation.
+  Ports mInputs;
+  Ports mOutputs;
+  ParameterValues mParameters;
+
+  RefPtr<AudioWorkletGlobalScope> mGlobal;
+  JS::PersistentRooted<JSObject*> mProcessor;
+
+  // mProcessorIsActive is named [[active source]] in the spec.
+  // It is initially true and so at least the first process()
+  // call will not be skipped when there are no active inputs.
+  bool mProcessorIsActive = true;
+  // mKeepEngineActive ensures another call to ProcessBlocksOnPorts(), even if
+  // there are no active inputs.  Its transitions to false lag those of
+  // mProcessorIsActive by one call to ProcessBlocksOnPorts() so that
+  // downstream engines can addref their nodes before this engine's node is
+  // released.
+  bool mKeepEngineActive = true;
+};
+
+void WorkletNodeEngine::SendErrorToMainThread(
+    AudioNodeTrack* aTrack, const ProcessorErrorDetails& aDetails) {
+  RefPtr<AudioNodeTrack> track = aTrack;
+  NS_DispatchToMainThread(NS_NewRunnableFunction(
+      "WorkletNodeEngine::SendProcessorError",
+      [track = std::move(track), aDetails]() mutable {
+        AudioWorkletNode* node =
+            static_cast<AudioWorkletNode*>(track->Engine()->NodeMainThread());
+        if (!node) {
+          return;
+        }
+        node->DispatchProcessorErrorEvent(aDetails);
+      }));
+}
+
+void WorkletNodeEngine::SendProcessorError(AudioNodeTrack* aTrack,
+                                           JSContext* aCx) {
+  // Note that once an exception is thrown, the processor will output silence
+  // throughout its lifetime.
+  ReleaseJSResources();
+  // The processor errored out while getting a context, try to tell the node
+  // anyways.
+  if (!aCx || !JS_IsExceptionPending(aCx)) {
+    ProcessorErrorDetails details;
+    details.mMessage.Assign(u"Unknown processor error");
+    SendErrorToMainThread(aTrack, details);
+    return;
+  }
+
+  JS::ExceptionStack exnStack(aCx);
+  if (JS::StealPendingExceptionStack(aCx, &exnStack)) {
+    JS::ErrorReportBuilder jsReport(aCx);
+    if (!jsReport.init(aCx, exnStack,
+                       JS::ErrorReportBuilder::WithSideEffects)) {
+      ProcessorErrorDetails details;
+      details.mMessage.Assign(u"Unknown processor error");
+      SendErrorToMainThread(aTrack, details);
+      // Set the exception and stack back to have it in the console with a stack
+      // trace.
+      JS::SetPendingExceptionStack(aCx, exnStack);
+      return;
+    }
+
+    ProcessorErrorDetails details;
+
+    CopyUTF8toUTF16(mozilla::MakeStringSpan(jsReport.report()->filename),
+                    details.mFilename);
+
+    xpc::ErrorReport::ErrorReportToMessageString(jsReport.report(),
+                                                 details.mMessage);
+    details.mLineno = jsReport.report()->lineno;
+    details.mColno = jsReport.report()->column;
+    MOZ_ASSERT(!jsReport.report()->isMuted);
+
+    SendErrorToMainThread(aTrack, details);
+
+    // Set the exception and stack back to have it in the console with a stack
+    // trace.
+    JS::SetPendingExceptionStack(aCx, exnStack);
+  } else {
+    NS_WARNING("No exception, but processor errored out?");
+  }
+}
+
+void WorkletNodeEngine::ConstructProcessor(
+    AudioWorkletImpl* aWorkletImpl, const nsAString& aName,
+    NotNull<StructuredCloneHolder*> aSerializedOptions,
+    UniqueMessagePortId& aPortIdentifier, AudioNodeTrack* aTrack) {
+  MOZ_ASSERT(mInputs.mPorts.empty() && mOutputs.mPorts.empty());
+  RefPtr<AudioWorkletGlobalScope> global = aWorkletImpl->GetGlobalScope();
+  if (!global) {
+    // A global was previously used to register this kind of processor.  If it
+    // no longer exists now, that is because the document is going away and so
+    // there is no need to send an error.
+    return;
+  }
+  AutoJSAPI api;
+  if (NS_WARN_IF(!api.Init(global))) {
+    SendProcessorError(aTrack, nullptr);
+    return;
+  }
+  mProcessorName = NS_ConvertUTF16toUTF8(aName);
+  JSContext* cx = api.cx();
+  mProcessor.init(cx);
+  if (!global->ConstructProcessor(cx, aName, aSerializedOptions,
+                                  aPortIdentifier, &mProcessor) ||
+      // mInputs and mOutputs outer arrays are fixed length and so much of the
+      // initialization need only be performed once (i.e. here).
+      NS_WARN_IF(!mInputs.mPorts.growBy(InputCount())) ||
+      NS_WARN_IF(!mOutputs.mPorts.growBy(OutputCount()))) {
+    SendProcessorError(aTrack, cx);
+    return;
+  }
+  mGlobal = std::move(global);
+  mInputs.mJSArray.init(cx);
+  mOutputs.mJSArray.init(cx);
+  for (auto& port : mInputs.mPorts) {
+    port.mJSArray.init(cx);
+  }
+  for (auto& port : mOutputs.mPorts) {
+    port.mJSArray.init(cx);
+  }
+  JSObject* object = JS_NewPlainObject(cx);
+  if (NS_WARN_IF(!object)) {
+    SendProcessorError(aTrack, cx);
+    return;
+  }
+
+  mParameters.mJSObject.init(cx, object);
+  if (NS_WARN_IF(!mParameters.mFloat32Arrays.growBy(ParameterCount()))) {
+    SendProcessorError(aTrack, cx);
+    return;
+  }
+  for (size_t i = 0; i < mParamTimelines.Length(); i++) {
+    auto& float32ArraysRef = mParameters.mFloat32Arrays;
+    float32ArraysRef[i].init(cx);
+    JSObject* array = JS_NewFloat32Array(cx, WEBAUDIO_BLOCK_SIZE);
+    if (NS_WARN_IF(!array)) {
+      SendProcessorError(aTrack, cx);
+      return;
+    }
+
+    float32ArraysRef[i] = array;
+    if (NS_WARN_IF(!JS_DefineUCProperty(
+            cx, mParameters.mJSObject, mParamTimelines[i].mName.get(),
+            mParamTimelines[i].mName.Length(), float32ArraysRef[i],
+            JSPROP_ENUMERATE))) {
+      SendProcessorError(aTrack, cx);
+      return;
+    }
+  }
+  if (NS_WARN_IF(!JS_FreezeObject(cx, mParameters.mJSObject))) {
+    SendProcessorError(aTrack, cx);
+    return;
+  }
+}
+
+// Type T should support the length() and operator[]() methods and the return
+// type of |operator[]() const| should support conversion to Handle<JSObject*>.
+template <typename T>
+static bool SetArrayElements(JSContext* aCx, const T& aElements,
+                             JS::Handle<JSObject*> aArray) {
+  for (size_t i = 0; i < aElements.length(); ++i) {
+    if (!JS_DefineElement(aCx, aArray, i, aElements[i], JSPROP_ENUMERATE)) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+template <typename T>
+static bool PrepareArray(JSContext* aCx, const T& aElements,
+                         JS::MutableHandle<JSObject*> aArray) {
+  size_t length = aElements.length();
+  if (aArray) {
+    // Attempt to reuse.
+    uint32_t oldLength;
+    if (JS::GetArrayLength(aCx, aArray, &oldLength) &&
+        (oldLength == length || JS::SetArrayLength(aCx, aArray, length)) &&
+        SetArrayElements(aCx, aElements, aArray)) {
+      return true;
+    }
+    // Script may have frozen the array.  Try again with a new Array.
+    JS_ClearPendingException(aCx);
+  }
+  JSObject* array = JS::NewArrayObject(aCx, length);
+  if (NS_WARN_IF(!array)) {
+    return false;
+  }
+  aArray.set(array);
+  return SetArrayElements(aCx, aElements, aArray);
+}
+
+enum class ArrayElementInit { None, Zero };
+
+// Exactly when to create new Float32Array and Array objects is not specified.
+// This approach aims to minimize garbage creation, while continuing to
+// function after objects are modified by content.
+// See https://github.com/WebAudio/web-audio-api/issues/1934 and
+// https://github.com/WebAudio/web-audio-api/issues/1933
+static bool PrepareBufferArrays(JSContext* aCx, Span<const AudioBlock> aBlocks,
+                                WorkletNodeEngine::Ports* aPorts,
+                                ArrayElementInit aInit) {
+  MOZ_ASSERT(aBlocks.Length() == aPorts->mPorts.length());
+  for (size_t i = 0; i < aBlocks.Length(); ++i) {
+    size_t channelCount = aBlocks[i].ChannelCount();
+    WorkletNodeEngine::Channels& portRef = aPorts->mPorts[i];
+
+    auto& float32ArraysRef = portRef.mFloat32Arrays;
+    for (auto& channelRef : float32ArraysRef) {
+      size_t length = JS_GetTypedArrayLength(channelRef);
+      if (length != WEBAUDIO_BLOCK_SIZE) {
+        // Script has detached array buffers.  Create new objects.
+        JSObject* array = JS_NewFloat32Array(aCx, WEBAUDIO_BLOCK_SIZE);
+        if (NS_WARN_IF(!array)) {
+          return false;
+        }
+        channelRef = array;
+      } else if (aInit == ArrayElementInit::Zero) {
+        // Need only zero existing arrays as new arrays are already zeroed.
+        JS::AutoCheckCannotGC nogc;
+        bool isShared;
+        float* elementData =
+            JS_GetFloat32ArrayData(channelRef, &isShared, nogc);
+        MOZ_ASSERT(!isShared);  // Was created as unshared
+        std::fill_n(elementData, WEBAUDIO_BLOCK_SIZE, 0.0f);
+      }
+    }
+    // Enlarge if necessary...
+    if (NS_WARN_IF(!float32ArraysRef.reserve(channelCount))) {
+      return false;
+    }
+    while (float32ArraysRef.length() < channelCount) {
+      JSObject* array = JS_NewFloat32Array(aCx, WEBAUDIO_BLOCK_SIZE);
+      if (NS_WARN_IF(!array)) {
+        return false;
+      }
+      float32ArraysRef.infallibleEmplaceBack(aCx, array);
+    }
+    // ... or shrink if necessary.
+    float32ArraysRef.shrinkTo(channelCount);
+
+    if (NS_WARN_IF(!PrepareArray(aCx, float32ArraysRef, &portRef.mJSArray))) {
+      return false;
+    }
+  }
+
+  return !(NS_WARN_IF(!PrepareArray(aCx, aPorts->mPorts, &aPorts->mJSArray)));
+}
+
+// This runs JS script.  MediaTrackGraph control messages, which would
+// potentially destroy the WorkletNodeEngine and its AudioNodeTrack, cannot
+// be triggered by script.  They are not run from an nsIThread event loop and
+// do not run until after ProcessBlocksOnPorts() has returned.
+bool WorkletNodeEngine::CallProcess(AudioNodeTrack* aTrack, JSContext* aCx,
+                                    JS::Handle<JS::Value> aCallable) {
+  TRACE_COMMENT("AudioWorkletNodeEngine::CallProcess", mProcessorName.get());
+
+  JS::RootedVector<JS::Value> argv(aCx);
+  if (NS_WARN_IF(!argv.resize(3))) {
+    return false;
+  }
+  argv[0].setObject(*mInputs.mJSArray);
+  argv[1].setObject(*mOutputs.mJSArray);
+  argv[2].setObject(*mParameters.mJSObject);
+  JS::Rooted<JS::Value> rval(aCx);
+  if (!JS::Call(aCx, mProcessor, aCallable, argv, &rval)) {
+    return false;
+  }
+
+  mProcessorIsActive = JS::ToBoolean(rval);
+  // Transitions of mProcessorIsActive to false do not trigger
+  // PlayingRefChangeHandler::RELEASE until silence is produced in the next
+  // block.  This allows downstream engines receiving this non-silence block
+  // to take a reference to their nodes before this engine's node releases its
+  // down node references.
+  if (mProcessorIsActive && !mKeepEngineActive) {
+    mKeepEngineActive = true;
+    RefPtr<PlayingRefChangeHandler> refchanged =
+        new PlayingRefChangeHandler(aTrack, PlayingRefChangeHandler::ADDREF);
+    aTrack->Graph()->DispatchToMainThreadStableState(refchanged.forget());
+  }
+  return true;
+}
+
+void WorkletNodeEngine::ProduceSilence(AudioNodeTrack* aTrack,
+                                       Span<AudioBlock> aOutput) {
+  if (mKeepEngineActive) {
+    mKeepEngineActive = false;
+    aTrack->ScheduleCheckForInactive();
+    RefPtr<PlayingRefChangeHandler> refchanged =
+        new PlayingRefChangeHandler(aTrack, PlayingRefChangeHandler::RELEASE);
+    aTrack->Graph()->DispatchToMainThreadStableState(refchanged.forget());
+  }
+  for (AudioBlock& output : aOutput) {
+    output.SetNull(WEBAUDIO_BLOCK_SIZE);
+  }
+}
+
+void WorkletNodeEngine::ProcessBlocksOnPorts(AudioNodeTrack* aTrack,
+                                             GraphTime aFrom,
+                                             Span<const AudioBlock> aInput,
+                                             Span<AudioBlock> aOutput,
+                                             bool* aFinished) {
+  MOZ_ASSERT(aInput.Length() == InputCount());
+  MOZ_ASSERT(aOutput.Length() == OutputCount());
+  TRACE("WorkletNodeEngine::ProcessBlocksOnPorts");
+
+  bool isSilent = true;
+  if (mProcessor) {
+    if (mProcessorIsActive) {
+      isSilent = false;  // call process()
+    } else {             // [[active source]] is false.
+      // Call process() only if an input is actively processing.
+      for (const AudioBlock& input : aInput) {
+        if (!input.IsNull()) {
+          isSilent = false;
+          break;
+        }
+      }
+    }
+  }
+  if (isSilent) {
+    ProduceSilence(aTrack, aOutput);
+    return;
+  }
+
+  if (!mOutputChannelCount.IsEmpty()) {
+    MOZ_ASSERT(mOutputChannelCount.Length() == aOutput.Length());
+    for (size_t o = 0; o < aOutput.Length(); ++o) {
+      aOutput[o].AllocateChannels(mOutputChannelCount[o]);
+    }
+  } else if (aInput.Length() == 1 && aOutput.Length() == 1) {
+    uint32_t channelCount = std::max(aInput[0].ChannelCount(), 1U);
+    aOutput[0].AllocateChannels(channelCount);
+  } else {
+    for (AudioBlock& output : aOutput) {
+      output.AllocateChannels(1);
+    }
+  }
+
+  AutoEntryScript aes(mGlobal, "Worklet Process");
+  JSContext* cx = aes.cx();
+  auto produceSilenceWithError = MakeScopeExit([this, aTrack, cx, &aOutput] {
+    SendProcessorError(aTrack, cx);
+    ProduceSilence(aTrack, aOutput);
+  });
+
+  JS::Rooted<JS::Value> process(cx);
+  if (!JS_GetProperty(cx, mProcessor, "process", &process) ||
+      !process.isObject() || !JS::IsCallable(&process.toObject()) ||
+      !PrepareBufferArrays(cx, aInput, &mInputs, ArrayElementInit::None) ||
+      !PrepareBufferArrays(cx, aOutput, &mOutputs, ArrayElementInit::Zero)) {
+    // process() not callable or OOM.
+    return;
+  }
+
+  // Copy input values to JS objects.
+  for (size_t i = 0; i < aInput.Length(); ++i) {
+    const AudioBlock& input = aInput[i];
+    size_t channelCount = input.ChannelCount();
+    if (channelCount == 0) {
+      // Null blocks have AUDIO_FORMAT_SILENCE.
+      // Don't call ChannelData<float>().
+      continue;
+    }
+    float volume = input.mVolume;
+    const auto& channelData = input.ChannelData<float>();
+    const auto& float32Arrays = mInputs.mPorts[i].mFloat32Arrays;
+    JS::AutoCheckCannotGC nogc;
+    for (size_t c = 0; c < channelCount; ++c) {
+      bool isShared;
+      float* dest = JS_GetFloat32ArrayData(float32Arrays[c], &isShared, nogc);
+      MOZ_ASSERT(!isShared);  // Was created as unshared
+      AudioBlockCopyChannelWithScale(channelData[c], volume, dest);
+    }
+  }
+
+  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];
+    size_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) {
+      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.
+    /**
+     * https://webaudio.github.io/web-audio-api/#dom-audioworkletnode-onprocessorerror
+     * Note that once an exception is thrown, the processor will output silence
+     * throughout its lifetime.
+     */
+    return;
+  }
+
+  // Copy output values from JS objects.
+  for (size_t o = 0; o < aOutput.Length(); ++o) {
+    AudioBlock* output = &aOutput[o];
+    size_t channelCount = output->ChannelCount();
+    const auto& float32Arrays = mOutputs.mPorts[o].mFloat32Arrays;
+    for (size_t c = 0; c < channelCount; ++c) {
+      size_t length = JS_GetTypedArrayLength(float32Arrays[c]);
+      if (length != WEBAUDIO_BLOCK_SIZE) {
+        // ArrayBuffer has been detached.  Behavior is unspecified.
+        // https://github.com/WebAudio/web-audio-api/issues/1933 and
+        // https://bugzilla.mozilla.org/show_bug.cgi?id=1619486
+        return;
+      }
+      JS::AutoCheckCannotGC nogc;
+      bool isShared;
+      const float* src =
+          JS_GetFloat32ArrayData(float32Arrays[c], &isShared, nogc);
+      MOZ_ASSERT(!isShared);  // Was created as unshared
+      PodCopy(output->ChannelFloatsForWrite(c), src, WEBAUDIO_BLOCK_SIZE);
+    }
+  }
+
+  produceSilenceWithError.release();  // have output and no error
+}
+
+AudioWorkletNode::AudioWorkletNode(AudioContext* aAudioContext,
+                                   const nsAString& aName,
+                                   const AudioWorkletNodeOptions& aOptions)
+    : AudioNode(aAudioContext, 2, ChannelCountMode::Max,
+                ChannelInterpretation::Speakers),
+      mNodeName(aName),
+      mInputCount(aOptions.mNumberOfInputs),
+      mOutputCount(aOptions.mNumberOfOutputs) {}
+
+void AudioWorkletNode::InitializeParameters(
+    nsTArray<NamedAudioParamTimeline>* aParamTimelines, ErrorResult& aRv) {
+  MOZ_ASSERT(!mParameters, "Only initialize the `parameters` attribute once.");
+  MOZ_ASSERT(aParamTimelines);
+
+  AudioContext* context = Context();
+  const AudioParamDescriptorMap* parameterDescriptors =
+      context->GetParamMapForWorkletName(mNodeName);
+  MOZ_ASSERT(parameterDescriptors);
+
+  size_t audioParamIndex = 0;
+  aParamTimelines->SetCapacity(parameterDescriptors->Length());
+
+  for (size_t i = 0; i < parameterDescriptors->Length(); i++) {
+    auto& paramEntry = (*parameterDescriptors)[i];
+    CreateAudioParam(audioParamIndex++, paramEntry.mName,
+                     paramEntry.mDefaultValue, paramEntry.mMinValue,
+                     paramEntry.mMaxValue);
+    aParamTimelines->AppendElement(paramEntry);
+  }
+}
+
+void AudioWorkletNode::SendParameterData(
+    const Optional<Record<nsString, double>>& aParameterData) {
+  MOZ_ASSERT(mTrack, "This method only works if the track has been created.");
+  nsAutoString name;
+  if (aParameterData.WasPassed()) {
+    const auto& paramData = aParameterData.Value();
+    for (const auto& paramDataEntry : paramData.Entries()) {
+      for (auto& audioParam : mParams) {
+        audioParam->GetName(name);
+        if (paramDataEntry.mKey.Equals(name)) {
+          audioParam->SetInitialValue(paramDataEntry.mValue);
+        }
+      }
+    }
+  }
+}
+
+/* static */
+already_AddRefed<AudioWorkletNode> AudioWorkletNode::Constructor(
+    const GlobalObject& aGlobal, AudioContext& aAudioContext,
+    const nsAString& aName, const AudioWorkletNodeOptions& aOptions,
+    ErrorResult& aRv) {
+  TRACE_COMMENT("AudioWorkletNode::Constructor", "%s",
+                NS_ConvertUTF16toUTF8(aName).get());
+  /**
+   * 1. If nodeName does not exist as a key in the BaseAudioContext’s node
+   *    name to parameter descriptor map, throw a InvalidStateError exception
+   *    and abort these steps.
+   */
+  const AudioParamDescriptorMap* parameterDescriptors =
+      aAudioContext.GetParamMapForWorkletName(aName);
+  if (!parameterDescriptors) {
+    // Not using nsPrintfCString in case aName has embedded nulls.
+    aRv.ThrowInvalidStateError("Unknown AudioWorklet name '"_ns +
+                               NS_ConvertUTF16toUTF8(aName) + "'"_ns);
+    return nullptr;
+  }
+
+  // See https://github.com/WebAudio/web-audio-api/issues/2074 for ordering.
+  RefPtr<AudioWorkletNode> audioWorkletNode =
+      new AudioWorkletNode(&aAudioContext, aName, aOptions);
+  audioWorkletNode->Initialize(aOptions, aRv);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return nullptr;
+  }
+
+  /**
+   * 3. Configure input, output and output channels of node with options.
+   */
+  if (aOptions.mNumberOfInputs == 0 && aOptions.mNumberOfOutputs == 0) {
+    aRv.ThrowNotSupportedError(
+        "Must have nonzero numbers of inputs or outputs");
+    return nullptr;
+  }
+
+  if (aOptions.mOutputChannelCount.WasPassed()) {
+    /**
+     * 1. If any value in outputChannelCount is zero or greater than the
+     *    implementation’s maximum number of channels, throw a
+     *    NotSupportedError and abort the remaining steps.
+     */
+    for (uint32_t channelCount : aOptions.mOutputChannelCount.Value()) {
+      if (channelCount == 0 || channelCount > WebAudioUtils::MaxChannelCount) {
+        aRv.ThrowNotSupportedError(
+            nsPrintfCString("Channel count (%u) must be in the range [1, max "
+                            "supported channel count]",
+                            channelCount));
+        return nullptr;
+      }
+    }
+    /**
+     * 2. If the length of outputChannelCount does not equal numberOfOutputs,
+     *    throw an IndexSizeError and abort the remaining steps.
+     */
+    if (aOptions.mOutputChannelCount.Value().Length() !=
+        aOptions.mNumberOfOutputs) {
+      aRv.ThrowIndexSizeError(
+          nsPrintfCString("Length of outputChannelCount (%zu) does not match "
+                          "numberOfOutputs (%u)",
+                          aOptions.mOutputChannelCount.Value().Length(),
+                          aOptions.mNumberOfOutputs));
+      return nullptr;
+    }
+  }
+  // MTG does not support more than UINT16_MAX inputs or outputs.
+  if (aOptions.mNumberOfInputs > UINT16_MAX) {
+    aRv.ThrowRangeError<MSG_VALUE_OUT_OF_RANGE>("numberOfInputs");
+    return nullptr;
+  }
+  if (aOptions.mNumberOfOutputs > UINT16_MAX) {
+    aRv.ThrowRangeError<MSG_VALUE_OUT_OF_RANGE>("numberOfOutputs");
+    return nullptr;
+  }
+
+  /**
+   * 4. Let messageChannel be a new MessageChannel.
+   */
+  RefPtr<MessageChannel> messageChannel =
+      MessageChannel::Constructor(aGlobal, aRv);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return nullptr;
+  }
+  /* 5. Let nodePort be the value of messageChannel’s port1 attribute.
+   * 6. Let processorPortOnThisSide be the value of messageChannel’s port2
+   *    attribute.
+   * 7. Let serializedProcessorPort be the result of
+   *    StructuredSerializeWithTransfer(processorPortOnThisSide,
+   *                                    « processorPortOnThisSide »).
+   */
+  UniqueMessagePortId processorPortId;
+  messageChannel->Port2()->CloneAndDisentangle(processorPortId);
+  /**
+   * 8. Convert options dictionary to optionsObject.
+   */
+  JSContext* cx = aGlobal.Context();
+  JS::Rooted<JS::Value> optionsVal(cx);
+  if (NS_WARN_IF(!ToJSValue(cx, aOptions, &optionsVal))) {
+    aRv.NoteJSContextException(cx);
+    return nullptr;
+  }
+
+  /**
+   * 9. Let serializedOptions be the result of
+   *    StructuredSerialize(optionsObject).
+   */
+
+  // This context and the worklet are part of the same agent cluster and they
+  // can share memory.
+  JS::CloneDataPolicy cloneDataPolicy;
+  cloneDataPolicy.allowIntraClusterClonableSharedObjects();
+  cloneDataPolicy.allowSharedMemoryObjects();
+
+  // StructuredCloneHolder does not have a move constructor.  Instead allocate
+  // memory so that the pointer can be passed to the rendering thread.
+  UniquePtr<StructuredCloneHolder> serializedOptions =
+      MakeUnique<StructuredCloneHolder>(
+          StructuredCloneHolder::CloningSupported,
+          StructuredCloneHolder::TransferringNotSupported,
+          JS::StructuredCloneScope::SameProcess);
+  serializedOptions->Write(cx, optionsVal, JS::UndefinedHandleValue,
+                           cloneDataPolicy, aRv);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return nullptr;
+  }
+  /**
+   * 10. Set node’s port to nodePort.
+   */
+  audioWorkletNode->mPort = messageChannel->Port1();
+
+  /**
+   * 11. Let parameterDescriptors be the result of retrieval of nodeName from
+   * node name to parameter descriptor map.
+   */
+  nsTArray<NamedAudioParamTimeline> paramTimelines;
+  audioWorkletNode->InitializeParameters(&paramTimelines, aRv);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return nullptr;
+  }
+
+  auto engine = new WorkletNodeEngine(
+      audioWorkletNode, aAudioContext.Destination(), std::move(paramTimelines),
+      aOptions.mOutputChannelCount);
+  audioWorkletNode->mTrack = AudioNodeTrack::Create(
+      &aAudioContext, engine, AudioNodeTrack::NO_TRACK_FLAGS,
+      aAudioContext.Graph());
+
+  audioWorkletNode->SendParameterData(aOptions.mParameterData);
+
+  /**
+   * 12. Queue a control message to invoke the constructor of the
+   *     corresponding AudioWorkletProcessor with the processor construction
+   *     data that consists of: nodeName, node, serializedOptions, and
+   *     serializedProcessorPort.
+   */
+  Worklet* worklet = aAudioContext.GetAudioWorklet(aRv);
+  MOZ_ASSERT(worklet, "Worklet already existed and so getter shouldn't fail.");
+  auto workletImpl = static_cast<AudioWorkletImpl*>(worklet->Impl());
+  audioWorkletNode->mTrack->SendRunnable(NS_NewRunnableFunction(
+      "WorkletNodeEngine::ConstructProcessor",
+  // MOZ_CAN_RUN_SCRIPT_BOUNDARY until Runnable::Run is MOZ_CAN_RUN_SCRIPT.
+  // See bug 1535398.
+  //
+  // Note that clang and gcc have mutually incompatible rules about whether
+  // attributes should come before or after the `mutable` keyword here, so
+  // use a compatibility hack until we can switch to the standardized
+  // [[attr]] syntax (bug 1627007).
+#ifdef __clang__
+#  define AND_MUTABLE(macro) macro mutable
+#else
+#  define AND_MUTABLE(macro) mutable macro
+#endif
+      [track = audioWorkletNode->mTrack,
+       workletImpl = RefPtr<AudioWorkletImpl>(workletImpl),
+       name = nsString(aName), options = std::move(serializedOptions),
+       portId = std::move(processorPortId)]()
+          AND_MUTABLE(MOZ_CAN_RUN_SCRIPT_BOUNDARY) {
+            auto engine = static_cast<WorkletNodeEngine*>(track->Engine());
+            engine->ConstructProcessor(
+                workletImpl, name, WrapNotNull(options.get()), portId, track);
+          }));
+#undef AND_MUTABLE
+
+  // [[active source]] is initially true and so at least the first process()
+  // call will not be skipped when there are no active inputs.
+  audioWorkletNode->MarkActive();
+
+  return audioWorkletNode.forget();
+}
+
+AudioParamMap* AudioWorkletNode::GetParameters(ErrorResult& aRv) {
+  if (!mParameters) {
+    RefPtr<AudioParamMap> parameters = new AudioParamMap(this);
+    nsAutoString name;
+    for (const auto& audioParam : mParams) {
+      audioParam->GetName(name);
+      AudioParamMap_Binding::MaplikeHelpers::Set(parameters, name, *audioParam,
+                                                 aRv);
+      if (NS_WARN_IF(aRv.Failed())) {
+        return nullptr;
+      }
+    }
+    mParameters = std::move(parameters);
+  }
+  return mParameters.get();
+}
+
+void AudioWorkletNode::DispatchProcessorErrorEvent(
+    const ProcessorErrorDetails& aDetails) {
+  TRACE("AudioWorkletNode::DispatchProcessorErrorEvent");
+  if (HasListenersFor(nsGkAtoms::onprocessorerror)) {
+    RootedDictionary<ErrorEventInit> init(RootingCx());
+    init.mMessage = aDetails.mMessage;
+    init.mFilename = aDetails.mFilename;
+    init.mLineno = aDetails.mLineno;
+    init.mColno = aDetails.mColno;
+    RefPtr<ErrorEvent> errorEvent =
+        ErrorEvent::Constructor(this, u"processorerror"_ns, init);
+    MOZ_ASSERT(errorEvent);
+    DispatchTrustedEvent(errorEvent);
+  }
+}
+
+JSObject* AudioWorkletNode::WrapObject(JSContext* aCx,
+                                       JS::Handle<JSObject*> aGivenProto) {
+  return AudioWorkletNode_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+size_t AudioWorkletNode::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
+  size_t amount = AudioNode::SizeOfExcludingThis(aMallocSizeOf);
+  return amount;
+}
+
+size_t AudioWorkletNode::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
+  return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+}
+
+}  // namespace mozilla::dom