Blink JavaScript shared memory prototype.

Source/wtf/ArrayBufferContents.h

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 11 matching lines @@
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef ArrayBufferContents_h
 #define ArrayBufferContents_h
 
 #include "wtf/ArrayBufferDeallocationObserver.h"
 #include "wtf/Noncopyable.h"
+#include "wtf/RefPtr.h"
+#include "wtf/ThreadSafeRefCounted.h"
 #include "wtf/WTFExport.h"
 
 namespace WTF {
 
+class DataHolder : public ThreadSafeRefCounted<DataHolder> {
+    WTF_MAKE_NONCOPYABLE(DataHolder);
+public:
+    DataHolder();
+    ~DataHolder();
+
+    void adopt(void* data, unsigned sizeInBytes, bool shared);
+
+    void* m_data;
+    unsigned m_sizeInBytes;
+    bool m_shared;
+};
+
 class WTF_EXPORT ArrayBufferContents {
     WTF_MAKE_NONCOPYABLE(ArrayBufferContents);
 public:
     enum InitializationPolicy {
         ZeroInitialize,
         DontInitialize
     };
 
     ArrayBufferContents();
     ArrayBufferContents(unsigned numElements, unsigned elementByteSize, ArrayBufferContents::InitializationPolicy);
 
     // Use with care. data must be allocated with allocateMemory.
     // ArrayBufferContents will take ownership of the data and free it (using freeMemorY)
     // upon destruction.
     // This constructor will not call observer->StartObserving(), so it is a responsibility
     // of the caller to make sure JS knows about external memory.
-    ArrayBufferContents(void* data, unsigned sizeInBytes, ArrayBufferDeallocationObserver*);
+    ArrayBufferContents(void* data, unsigned sizeInBytes, bool shared, ArrayBufferDeallocationObserver*);
 
     ~ArrayBufferContents();
 
     void clear();
 
-    void* data() const { return m_data; }
-    unsigned sizeInBytes() const { return m_sizeInBytes; }
+    void* data() const { return m_holder->m_data; }
+    unsigned sizeInBytes() const { return m_holder->m_sizeInBytes; }
+    bool shared() const { return m_holder->m_shared; }
 
     void setDeallocationObserver(ArrayBufferDeallocationObserver* observer)
     {
         if (!m_deallocationObserver) {
             m_deallocationObserver = observer;
-            m_deallocationObserver->blinkAllocatedMemory(m_sizeInBytes);
+            m_deallocationObserver->blinkAllocatedMemory(m_holder->m_sizeInBytes);
         }
     }
 
     void transfer(ArrayBufferContents& other);
     void copyTo(ArrayBufferContents& other);
 
     static void allocateMemory(size_t, InitializationPolicy, void*&);
     static void freeMemory(void*, size_t);
 
 private:
-    void* m_data;
-    unsigned m_sizeInBytes;
+    RefPtr<DataHolder> m_holder;
     ArrayBufferDeallocationObserver* m_deallocationObserver;
 };
 
 } // namespace WTF
 
 #endif // ArrayBufferContents_h