1 files changed, 140 insertions, 0 deletions
diff --git a/dom/media/webaudio/AudioParamTimeline.h b/dom/media/webaudio/AudioParamTimeline.h
new file mode 100644
index 0000000000..5c1c725c10
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+++ b/dom/media/webaudio/AudioParamTimeline.h
@@ -0,0 +1,140 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+#ifndef AudioParamTimeline_h_
+#define AudioParamTimeline_h_
+
+#include "AudioEventTimeline.h"
+#include "AudioNodeTrack.h"
+#include "AudioSegment.h"
+
+namespace mozilla::dom {
+
+// This helper class is used to represent the part of the AudioParam
+// class that gets sent to AudioNodeEngine instances.  In addition to
+// AudioEventTimeline methods, it holds a pointer to an optional
+// AudioNodeTrack which represents the AudioNode inputs to the AudioParam.
+// This AudioNodeTrack is managed by the AudioParam subclass on the main
+// thread, and can only be obtained from the AudioNodeEngine instances
+// consuming this class.
+class AudioParamTimeline : public AudioEventTimeline {
+  typedef AudioEventTimeline BaseClass;
+
+ public:
+  explicit AudioParamTimeline(float aDefaultValue) : BaseClass(aDefaultValue) {}
+
+  AudioNodeTrack* Track() const { return mTrack; }
+
+  bool HasSimpleValue() const {
+    return BaseClass::HasSimpleValue() &&
+           (!mTrack || mTrack->LastChunks()[0].IsNull());
+  }
+
+  template <class TimeType>
+  float GetValueAtTime(TimeType aTime) {
+    return GetValueAtTime(aTime, 0);
+  }
+
+  template <typename TimeType>
+  void InsertEvent(const AudioTimelineEvent& aEvent) {
+    if (aEvent.mType == AudioTimelineEvent::Cancel) {
+      CancelScheduledValues(aEvent.Time<TimeType>());
+      return;
+    }
+    if (aEvent.mType == AudioTimelineEvent::Track) {
+      mTrack = aEvent.mTrack;
+      return;
+    }
+    if (aEvent.mType == AudioTimelineEvent::SetValue) {
+      AudioEventTimeline::SetValue(aEvent.mValue);
+      return;
+    }
+    AudioEventTimeline::InsertEvent<TimeType>(aEvent);
+  }
+
+  // Get the value of the AudioParam at time aTime + aCounter.
+  // aCounter here is an offset to aTime if we try to get the value in ticks,
+  // otherwise it should always be zero.  aCounter is meant to be used when
+  template <class TimeType>
+  float GetValueAtTime(TimeType aTime, size_t aCounter);
+
+  // Get the values of the AudioParam at time aTime + (0 to aSize).
+  // aBuffer must have the correct aSize.
+  // aSize here is an offset to aTime if we try to get the value in ticks,
+  // otherwise it should always be zero.  aSize is meant to be used when
+  // getting the value of an a-rate AudioParam for each tick inside an
+  // AudioNodeEngine implementation.
+  template <class TimeType>
+  void GetValuesAtTime(TimeType aTime, float* aBuffer, const size_t aSize);
+
+  virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
+    return mTrack ? mTrack->SizeOfIncludingThis(aMallocSizeOf) : 0;
+  }
+
+  virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
+    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+ private:
+  float AudioNodeInputValue(size_t aCounter) const;
+
+ protected:
+  // This is created lazily when needed.
+  RefPtr<AudioNodeTrack> mTrack;
+};
+
+template <>
+inline float AudioParamTimeline::GetValueAtTime(double aTime, size_t aCounter) {
+  MOZ_ASSERT(!aCounter);
+
+  // Getting an AudioParam value on an AudioNode does not consider input from
+  // other AudioNodes, which is managed only on the graph thread.
+  return BaseClass::GetValueAtTime(aTime);
+}
+
+template <>
+inline float AudioParamTimeline::GetValueAtTime(int64_t aTime,
+                                                size_t aCounter) {
+  MOZ_ASSERT(aCounter < WEBAUDIO_BLOCK_SIZE);
+  MOZ_ASSERT(!aCounter || !HasSimpleValue());
+
+  // Mix the value of the AudioParam itself with that of the AudioNode inputs.
+  return BaseClass::GetValueAtTime(static_cast<int64_t>(aTime + aCounter)) +
+         (mTrack ? AudioNodeInputValue(aCounter) : 0.0f);
+}
+
+template <>
+inline void AudioParamTimeline::GetValuesAtTime(double aTime, float* aBuffer,
+                                                const size_t aSize) {
+  MOZ_ASSERT(aBuffer);
+  MOZ_ASSERT(aSize == 1);
+
+  // Getting an AudioParam value on an AudioNode does not consider input from
+  // other AudioNodes, which is managed only on the graph thread.
+  *aBuffer = BaseClass::GetValueAtTime(aTime);
+}
+
+template <>
+inline void AudioParamTimeline::GetValuesAtTime(int64_t aTime, float* aBuffer,
+                                                const size_t aSize) {
+  MOZ_ASSERT(aBuffer);
+  MOZ_ASSERT(aSize <= WEBAUDIO_BLOCK_SIZE);
+  MOZ_ASSERT(aSize == 1 || !HasSimpleValue());
+
+  // Mix the value of the AudioParam itself with that of the AudioNode inputs.
+  BaseClass::GetValuesAtTime(aTime, aBuffer, aSize);
+  if (mTrack) {
+    uint32_t blockOffset = aTime % WEBAUDIO_BLOCK_SIZE;
+    MOZ_ASSERT(blockOffset + aSize <= WEBAUDIO_BLOCK_SIZE);
+    for (size_t i = 0; i < aSize; ++i) {
+      aBuffer[i] += AudioNodeInputValue(blockOffset + i);
+    }
+  }
+}
+
+}  // namespace mozilla::dom
+
+#endif