Sharing of SharedArrayBuffer via PostMessage transfer

Source/core/dom/DOMTypedArray.cpp

Index: Source/core/dom/DOMTypedArray.cpp
diff --git a/Source/core/dom/DOMTypedArray.cpp b/Source/core/dom/DOMTypedArray.cpp
index c5d5e327d018c255fc63682c4ee9b7566ddf929b..f9ffccefd3542d0957cc74e313358a4e9b48a05d 100644
--- a/Source/core/dom/DOMTypedArray.cpp
+++ b/Source/core/dom/DOMTypedArray.cpp
@@ -31,13 +31,25 @@ v8::Local<v8::Object> DOMTypedArray<WTFTypedArray, V8TypedArray>::wrap(v8::Isola
     ASSERT(!DOMDataStore::containsWrapper(this, isolate));
 
     const WrapperTypeInfo* wrapperTypeInfo = this->wrapperTypeInfo();
-    RefPtr<DOMArrayBuffer> buffer = this->buffer();
-    v8::Local<v8::Value> v8Buffer = toV8(buffer.get(), creationContext, isolate);
+    v8::Local<v8::Value> v8Buffer;
+    v8::Local<v8::Object> wrapper;
+    if (isShared()) {

[Yuki, 2015/06/09 06:18:07]

Why don't you use DOMArrayBufferView::bufferBase() that you introduced in this
CL?  You don't need any if-branch, I think.

RefPtr<DOMArrayBufferBase> buffer = this->bufferBase();
v8::Local<v8::Value> v8Buffer = toV8(buffer.get(), creationContext, isolate);
// optional check if you want
if (ENABLE_ASSERT) {
  if (isShared())
    ASSERT(v8Buffer->IsSharedArrayBuffer());
  else
    ASSERT(v8Buffer->IsArrayBuffer());
}
// or
ASSERT(isShared() == v8Buffer->IsSharedArrayBuffer());
ASSERT(v8Buffer->IsArrayBuffer());  // SharedArrayBuffer is an ArrayBuffer,
right?  Otherwise, !isShared() == v8Buffer->IsArrayBuffer().

[binji, 2015/06/10 06:04:39]

I only added it recently, but I've tried to simplify the CL by using it.
Done.

+        RefPtr<DOMSharedArrayBuffer> buffer = this->bufferShared();
+        v8Buffer = toV8(buffer.get(), creationContext, isolate);
+        ASSERT(v8Buffer->IsSharedArrayBuffer());
+    } else {
+        RefPtr<DOMArrayBuffer> buffer = this->buffer();
+        v8Buffer = toV8(buffer.get(), creationContext, isolate);
+        ASSERT(v8Buffer->IsArrayBuffer());
+    }
     if (v8Buffer.IsEmpty())
         return v8::Handle<v8::Object>();
-    ASSERT(v8Buffer->IsArrayBuffer());
 
-    v8::Local<v8::Object> wrapper = V8TypedArray::New(v8Buffer.As<v8::ArrayBuffer>(), byteOffset(), length());
+    if (isShared()) {

[Yuki, 2015/06/09 06:18:07]

Declare |wrapper| just before its use.

[binji, 2015/06/10 06:04:39]

Done.

+        wrapper = V8TypedArray::New(v8Buffer.As<v8::ArrayBuffer>(), byteOffset(), length());
+    } else {
+        wrapper = V8TypedArray::New(v8Buffer.As<v8::SharedArrayBuffer>(), byteOffset(), length());
+    }
 
     return associateWithWrapper(isolate, wrapperTypeInfo, wrapper);
 }