[SharedArrayBuffer] Prevent SharedArrayBuffer being used in Web APIs

third_party/WebKit/Source/core/dom/NotShared.h

Index: third_party/WebKit/Source/core/dom/NotShared.h
diff --git a/third_party/WebKit/Source/core/dom/NotShared.h b/third_party/WebKit/Source/core/dom/NotShared.h
new file mode 100644
index 0000000000000000000000000000000000000000..28cc38906cfc1bbcfa60ff560c4d2a730620482b
--- /dev/null
+++ b/third_party/WebKit/Source/core/dom/NotShared.h
@@ -0,0 +1,68 @@
+// 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 NotShared_h
+#define NotShared_h
+
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+template <typename T>
+class CORE_EXPORT NotShared {

[haraken, 2017/04/06 08:43:54]

Add a class-level comment.

[binji, 2017/04/09 00:40:02]

Done.

+  STACK_ALLOCATED();
+
+ public:
+  using TypedArrayType = T;
+
+  NotShared() {}
+
+  explicit NotShared(T* typedArray) : m_typedArray(typedArray) {
+    DCHECK(!(typedArray && typedArray->view()->isShared()));
+  }
+  NotShared(const NotShared& other) = default;
+  template <typename U>
+  NotShared(const NotShared<U>& other) : m_typedArray(other.view()) {}
+  template <typename U>
+  NotShared(const Member<U>& other) {
+    DCHECK(!other->view()->isShared());
+    m_typedArray = *other;
+  }
+
+#if 0

[haraken, 2017/04/06 08:43:54]

Remove this.

[binji, 2017/04/09 00:40:02]

Done.

+  NotShared& operator=(T* typedArray) {
+    DCHECK(!typedArray->view()->isShared());
+    m_typedArray = typedArray;
+    return *this;
+  }
+#endif
+  NotShared& operator=(const NotShared& other) = default;
+  template <typename U>
+  NotShared& operator=(const NotShared<U>& other) {
+    m_typedArray = other.view();
+    return *this;
+  }
+#if 0

[haraken, 2017/04/06 08:43:54]

Remove this.

[binji, 2017/04/09 00:40:02]

Done.

+  template <typename U>
+  NotShared& operator=(const Member<U>& other) {
+    DCHECK(!other->view()->isShared());
+    m_typedArray = *other;
+    return *this;
+  }
+#endif
+
+  T* view() const { return m_typedArray.get(); }
+
+  bool operator!() const { return !m_typedArray; }
+  explicit operator bool() const { return !!m_typedArray; }
+  operator ScriptWrappable*() const { return m_typedArray.get(); }
+  operator Member<T>() const { return Member<T>(m_typedArray.get()); }

[haraken, 2017/04/06 08:43:54]

I'd prefer not adding these implicit conversions. If we remove them, do we need
to add a lot of manual conversions?

[binji, 2017/04/09 00:40:02]

Done.

+
+ private:
+  Member<T> m_typedArray;
+};
+
+}  // namespace blink
+
+#endif  // NotShared_h