AudioWorklet prototype

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

 // Copyright 2016 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 AudioWorkletMessagingProxy_h
 #define AudioWorkletMessagingProxy_h
 
-#include <memory>
-#include "core/workers/ThreadedWorkletMessagingProxy.h"
-#include "platform/wtf/Allocator.h"
+#include "core/CoreExport.h"
+#include "core/loader/WorkletScriptLoader.h"
+#include "core/workers/ThreadedMessagingProxyBase.h"
+#include "core/workers/WorkletGlobalScopeProxy.h"
+#include "core/workers/WorkletPendingTasks.h"
+#include "platform/wtf/WeakPtr.h"
 
 namespace blink {
 
-class ExecutionContext;
-class WorkerThread;
+class AudioWorkletHandler;
+class AudioWorkletObjectProxy;
+class ScriptSourceCode;
+class WaitableEvent;
+class WebThreadSupportingGC;
 
-class AudioWorkletMessagingProxy final : public ThreadedWorkletMessagingProxy {
-  USING_FAST_MALLOC(AudioWorkletMessagingProxy);
+// NOTE: Currently this class is a duplication of ThreadedWorkletMessagingProxy,
+// because it needs to have the ownership of the worker thread.
+// 
+// When rebasing the code, make sure to copy the behavior of
+// |ThreadedWorkletMessagingProxy| instead of inheriting from it. Think of this
+// class is a composition of |ThreadedWorkletMessagingProxy| and
+// |AudioWorkletMessagingProxy|. This is because we need a direct access of
+// |worklet_object_proxy| from BaseAudioContext.
 
+class CORE_EXPORT AudioWorkletMessagingProxy
+    : public ThreadedMessagingProxyBase,
+      public WorkletGlobalScopeProxy {
  public:
   AudioWorkletMessagingProxy(ExecutionContext*, WorkerClients*);
 
+  // WorkletGlobalScopeProxy implementation.
+  void FetchAndInvokeScript(const KURL& module_url_record,
+                            WebURLRequest::FetchCredentialsMode,
+                            RefPtr<WebTaskRunner> outside_settings_task_runner,
+                            WorkletPendingTasks*) final;
+  void TerminateWorkletGlobalScope() final;
+  void Initialize();
+
+  // This blocks the main thread until the rendering thread completes the
+  // creation of AudioWorkletProcessor.
+  void CreateProcessorInstance(const String& name,
+                               AudioWorkletHandler*,
+                               WaitableEvent*);
+
+  // This returns the rendering thread so it can be passed to AudioDestination.
+  WebThreadSupportingGC* GetRenderingThread();
+
  protected:
-  ~AudioWorkletMessagingProxy() override;
+  ~AudioWorkletMessagingProxy();
+
+  AudioWorkletObjectProxy& WorkletObjectProxy() {
+    return *worklet_object_proxy_;
+  }
 
   std::unique_ptr<WorkerThread> CreateWorkerThread(double origin_time) override;
+
+ private:
+  friend class AudioWorkletMessagingProxyForTest;
+  class LoaderClient;
+
+  void NotifyLoadingFinished(WorkletScriptLoader*);
+  void EvaluateScript(const ScriptSourceCode&);
+
+  std::unique_ptr<AudioWorkletObjectProxy> worklet_object_proxy_;

[nhiroki, 2017/06/07 14:43:52]

If having the AudioWorkletObjectProxy is the only difference from
ThreadedWorkletMessagingProxy, how about adding a virtual function to create the
object proxy in ThreadedWorkletMessagingProxy, making AudioWorkletMessagingProxy
override it and calling it in the ctor of ThreadedWorkletMessagingProxy like
this?

ThreadedWorkletMessagingProxy::ThreadedWorkletMessagingProxy(
    ExecutionContext* execution_context,
    WorkerClients* worker_clients)
    : ThreadedMessagingProxyBase(execution_context, worker_clients),
      weak_ptr_factory_(this) {
//  worklet_object_proxy_ = ThreadedWorkletObjectProxy::Create(
//      weak_ptr_factory_.CreateWeakPtr(), GetParentFrameTaskRunners());

  // CreateObjectProxy() is a virtual function and overridden
  // by AudioWorkletMessagingProxy.
  worklet_object_proxy_ = CreateObjectProxy(
      weak_ptr_factory_CreateWeakPtr(), GetParentFrameTaskRunners());
}

class AudioWorkletMessagingProxy : public ThreadedMessagingProxyBase {
 private:
   std::unique_ptr<WorkletObjectProxy> CreateObjectProxy(...) override {
     return WTF::MakeUnique<AudioWorkletObjectProxy>(...);
   }
}

+  HashSet<Persistent<WorkletScriptLoader>> loaders_;
+  WeakPtrFactory<AudioWorkletMessagingProxy> weak_ptr_factory_;
 };
 
 }  // namespace blink
 
 #endif  // AudioWorkletMessagingProxy_h