Bug 1322883 - AudioNode constructors - part 2 - GainNode, r=padenot

dom/media/webaudio/AudioContext.cpp

@@ -12,6 +12,9 @@
 #include "mozilla/OwningNonNull.h"
 
 #include "mozilla/dom/AnalyserNode.h"
+#include "mozilla/dom/AnalyserNodeBinding.h"
+#include "mozilla/dom/AudioBufferSourceNodeBinding.h"
+#include "mozilla/dom/GainNodeBinding.h"
 #include "mozilla/dom/AudioContextBinding.h"
 #include "mozilla/dom/HTMLMediaElement.h"
 #include "mozilla/dom/OfflineAudioContextBinding.h"
@@ -395,12 +398,7 @@ AudioContext::CreateMediaStreamSource(DOMMediaStream& aMediaStream,
 already_AddRefed<GainNode>
 AudioContext::CreateGain(ErrorResult& aRv)
 {
-  if (CheckClosed(aRv)) {
-    return nullptr;
-  }
-
-  RefPtr<GainNode> gainNode = new GainNode(this);
-  return gainNode.forget();
+  return GainNode::Create(*this, GainOptions(), aRv);
 }
 
 already_AddRefed<WaveShaperNode>

dom/media/webaudio/GainNode.cpp

@@ -128,8 +128,24 @@ GainNode::GainNode(AudioContext* aContext)
                                     aContext->Graph());
 }
 
-GainNode::~GainNode()
+/* static */ already_AddRefed<GainNode>
+GainNode::Create(AudioContext& aAudioContext,
+                 const GainOptions& aOptions,
+                 ErrorResult& aRv)
 {
+  if (aAudioContext.CheckClosed(aRv)) {
+    return nullptr;
+  }
+
+  RefPtr<GainNode> audioNode = new GainNode(&aAudioContext);
+
+  audioNode->Initialize(aOptions, aRv);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return nullptr;
+  }
+
+  audioNode->Gain()->SetValue(aOptions.mGain);
+  return audioNode.forget();
 }
 
 size_t

dom/media/webaudio/GainNode.h

@@ -14,15 +14,25 @@ namespace mozilla {
 namespace dom {
 
 class AudioContext;
+struct GainOptions;
 
 class GainNode final : public AudioNode
 {
 public:
-  explicit GainNode(AudioContext* aContext);
+  static already_AddRefed<GainNode>
+  Create(AudioContext& aAudioContext, const GainOptions& aOptions,
+         ErrorResult& aRv);
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(GainNode, AudioNode)
 
+  static already_AddRefed<GainNode>
+  Constructor(const GlobalObject& aGlobal, AudioContext& aAudioContext,
+              const GainOptions& aOptions, ErrorResult& aRv)
+  {
+    return Create(aAudioContext, aOptions, aRv);
+  }
+
   JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
   AudioParam* Gain() const
@@ -38,10 +48,10 @@ public:
   size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override;
   size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override;
 
-protected:
-  virtual ~GainNode();
-
 private:
+  explicit GainNode(AudioContext* aContext);
+  ~GainNode() = default;
+
   RefPtr<AudioParam> mGain;
 };
 
@@ -49,4 +59,3 @@ private:
 } // namespace mozilla
 
 #endif
-

dom/media/webaudio/test/test_gainNode.html

@@ -14,17 +14,32 @@ var gTest = {
   length: 2048,
   numberOfChannels: 1,
   createGraph: function(context) {
+
+    var gain = new GainNode(context);
+    ok(gain.gain, "The audioparam member must exist");
+    is(gain.gain.value, 1.0, "Correct initial value");
+    is(gain.gain.defaultValue, 1.0, "Correct default value");
+    gain.gain.value = 0.5;
+    is(gain.gain.value, 0.5, "Correct initial value");
+    is(gain.gain.defaultValue, 1.0, "Correct default value");
+
+    gain = new GainNode(context, { gain: 0.5 });
+    ok(gain.gain, "The audioparam member must exist");
+    is(gain.gain.value, 0.5, "Correct initial value");
+    is(gain.gain.defaultValue, 1.0, "Correct default value");
+    gain.gain.value = 0.5;
+    is(gain.gain.value, 0.5, "Correct initial value");
+    is(gain.gain.defaultValue, 1.0, "Correct default value");
+
     var buffer = context.createBuffer(1, 2048, context.sampleRate);
     for (var i = 0; i < 2048; ++i) {
       buffer.getChannelData(0)[i] = Math.sin(440 * 2 * Math.PI * i / context.sampleRate);
     }
 
     var source = context.createBufferSource();
-
-    var gain = context.createGain();
-
     source.buffer = buffer;
 
+    gain = context.createGain();
     source.connect(gain);
 
     ok(gain.gain, "The audioparam member must exist");

dom/webidl/GainNode.webidl

@@ -10,7 +10,12 @@
  * liability, trademark and document use rules apply.
  */
 
-[Pref="dom.webaudio.enabled"]
+dictionary GainOptions : AudioNodeOptions {
+             float gain = 1.0;
+};
+
+[Pref="dom.webaudio.enabled",
+ Constructor(AudioContext context, optional GainOptions options)]
 interface GainNode : AudioNode {
 
     readonly attribute AudioParam gain;

testing/web-platform/tests/webaudio/the-audio-api/the-gainnode-interface/idl-test.html

@@ -125,7 +125,12 @@ interface AudioNode : EventTarget {
 
 };</pre>
 
-<pre id="gain-node-idl">interface GainNode : AudioNode {
+<pre id="gain-node-idl">dictionary GainOptions : AudioNodeOptions {
+             float gain = 1.0;
+};
+
+[Constructor(AudioContext context, optional GainOptions options)]
+interface GainNode : AudioNode {
 
     readonly attribute AudioParam gain;