Implement AudioWorkletProcessor interface

third_party/WebKit/Source/modules/webaudio/AudioWorkletProcessorDefinition.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef AudioWorkletProcessorDefinition_h
+#define AudioWorkletProcessorDefinition_h
+
+#include "bindings/core/v8/ScopedPersistent.h"
+#include "platform/heap/Handle.h"
+#include "v8/include/v8.h"
+
+namespace blink {
+
+class AudioBuffer;
+class ScriptState;
+
+// Represents a JavaScript class definition registered in the
+// AudioWorkletGlobalScope. After the registration, a definition class contains
+// the V8 representation of class components (constructor, process callback,
+// prototypes and parameter descriptors).
+//
+// This is constructed and destroyed on a worker thread, and all methods also
+// must be called on the worker thread.
+class AudioWorkletProcessorDefinition final
+    : public GarbageCollectedFinalized<AudioWorkletProcessorDefinition> {
+ public:
+  static AudioWorkletProcessorDefinition* create(
+      ScriptState*,
+      v8::Local<v8::Function> constructor,
+      v8::Local<v8::Function> process);
+
+  virtual ~AudioWorkletProcessorDefinition();
+
+  // Create a V8 object instance of |AudioWorkletProcessor| from the definition.
+  void createInstance(ScopedPersistent<v8::Object>& instance);
+
+  // Perform process() call with an |AudioWorkletProcessor| instance.
+  bool process(ScopedPersistent<v8::Object>& instance,
+               AudioBuffer* inputBuffer,
+               AudioBuffer* outputBuffer);
+
+  ScriptState* getScriptState() const { return m_scriptState.get(); }
+
+  DEFINE_INLINE_TRACE(){};
+
+ private:
+  AudioWorkletProcessorDefinition(ScriptState*,
+                                  v8::Local<v8::Function> constructor,
+                                  v8::Local<v8::Function> process);
+
+  RefPtr<ScriptState> m_scriptState;
+
+  // The definition is per global scope. The active instance of
+  // |AudioProcessorWorklet| should be passed into these to perform JS function.
+  ScopedPersistent<v8::Function> m_constructor;
+  ScopedPersistent<v8::Function> m_process;

[haraken, 2017/03/08 09:57:19]

Just to confirm: You're intending to keep these objects alive until the
AudioWorkletGlobalScope is disposed, right? And these ScopedPersistents are
destroyed when the AudioWorkletGlobalScope is disposed. If yes, this looks fine.

(In general, we should use ScopedPersistent very carefully since it strongly
holds V8 objects, which sometimes causes memory leaks.)

[hongchan, 2017/03/08 19:38:46]

Correct. This definition is owned by AWGS and it is destroyed when the global
scope goes away.

+
+  // TODO(hongchan): A container for AudioParamDescriptor objects.
+  // ScopedPersistent<v8::Array> m_parameterDescriptors;
+};
+
+}  // namespace blink
+
+#endif  // AudioWorkletProcessorDefinition_h