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      1 /*
      2  * Copyright (C) 2012 Google, Inc. All Rights Reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #ifndef RefCountedSupplement_h
     27 #define RefCountedSupplement_h
     28 
     29 #include "core/platform/Supplementable.h"
     30 #include "wtf/RefCounted.h"
     31 #include "wtf/RefPtr.h"
     32 
     33 namespace WebCore {
     34 
     35 template<class T, class S>
     36 class RefCountedSupplement : public RefCounted<S> {
     37 public:
     38     typedef RefCountedSupplement<T, S> ThisType;
     39 
     40     virtual ~RefCountedSupplement() { }
     41     virtual void hostDestroyed() { }
     42 
     43     class Wrapper : public Supplement<T> {
     44     public:
     45         explicit Wrapper(PassRefPtr<ThisType> wrapped) : m_wrapped(wrapped) { }
     46         virtual ~Wrapper() { m_wrapped->hostDestroyed();  }
     47 #if !ASSERT_DISABLED || defined(ADDRESS_SANITIZER)
     48         virtual bool isRefCountedWrapper() const OVERRIDE { return true; }
     49 #endif
     50         ThisType* wrapped() const { return m_wrapped.get(); }
     51     private:
     52 
     53         RefPtr<ThisType> m_wrapped;
     54     };
     55 
     56     static void provideTo(Supplementable<T>* host, const char* key, PassRefPtr<ThisType> supplement)
     57     {
     58         host->provideSupplement(key, adoptPtr(new Wrapper(supplement)));
     59     }
     60 
     61     static ThisType* from(Supplementable<T>* host, const char* key)
     62     {
     63         Supplement<T>* found = host->requireSupplement(key);
     64         if (!found)
     65             return 0;
     66         ASSERT_WITH_SECURITY_IMPLICATION(found->isRefCountedWrapper());
     67         return static_cast<Wrapper*>(found)->wrapped();
     68     }
     69 };
     70 
     71 } // namespace WebCore
     72 
     73 #endif // RefCountedSupplement_h
     74