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      1 /*
      2  * Copyright (C) 2009 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 are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef DOMData_h
     32 #define DOMData_h
     33 
     34 #include "DOMDataStore.h"
     35 #include "V8DOMWrapper.h"
     36 
     37 namespace WebCore {
     38 
     39     // DOMData
     40     //
     41     // DOMData represents the all the DOM wrappers for a given thread.  In
     42     // particular, DOMData holds wrappers for all the isolated worlds in the
     43     // thread.  The DOMData for the main thread and the DOMData for child threads
     44     // use different subclasses.
     45     //
     46     class DOMData {
     47         WTF_MAKE_NONCOPYABLE(DOMData);
     48     public:
     49         DOMData();
     50         virtual ~DOMData();
     51 
     52         static DOMData* getCurrent();
     53         virtual DOMDataStore& getStore() = 0;
     54 
     55         template<typename T>
     56         static void handleWeakObject(DOMDataStore::DOMWrapperMapType, v8::Persistent<v8::Object>, T* domObject);
     57 
     58         template<typename T>
     59         static void removeObjectsFromWrapperMap(DOMDataStore* store, AbstractWeakReferenceMap<T, v8::Object>& domMap);
     60 
     61         ThreadIdentifier owningThread() const { return m_owningThread; }
     62 
     63     private:
     64         static void derefObject(WrapperTypeInfo* type, void* domObject);
     65 
     66         template<typename T>
     67         class WrapperMapObjectRemover : public WeakReferenceMap<T, v8::Object>::Visitor {
     68         public:
     69             virtual void visitDOMWrapper(DOMDataStore* store, T* domObject, v8::Persistent<v8::Object> v8Object)
     70             {
     71                 WrapperTypeInfo* type = V8DOMWrapper::domWrapperType(v8Object);
     72                 derefObject(type, domObject);
     73                 v8Object.Dispose();
     74             }
     75         };
     76 
     77         ThreadIdentifier m_owningThread;
     78     };
     79 
     80     template<typename T>
     81     void DOMData::handleWeakObject(DOMDataStore::DOMWrapperMapType mapType, v8::Persistent<v8::Object> v8Object, T* domObject)
     82     {
     83         WrapperTypeInfo* type = V8DOMWrapper::domWrapperType(v8Object);
     84         DOMDataList& list = DOMDataStore::allStores();
     85         bool found = false;
     86         for (size_t i = 0; i < list.size(); ++i) {
     87             DOMDataStore* store = list[i];
     88             ASSERT(store->domData()->owningThread() == WTF::currentThread());
     89 
     90             DOMWrapperMap<T>* domMap = static_cast<DOMWrapperMap<T>*>(store->getDOMWrapperMap(mapType));
     91             if (domMap->removeIfPresent(domObject, v8Object)) {
     92                 derefObject(type, domObject);
     93                 found = true;
     94             }
     95         }
     96 
     97         // If not found, it means map for the wrapper has been already destroyed, just dispose the
     98         // handle and deref the object to fight memory leak.
     99         if (!found) {
    100             v8Object.Dispose();
    101             derefObject(type, domObject);
    102         }
    103     }
    104 
    105     template<typename T>
    106     void DOMData::removeObjectsFromWrapperMap(DOMDataStore* store, AbstractWeakReferenceMap<T, v8::Object>& domMap)
    107     {
    108         WrapperMapObjectRemover<T> remover;
    109         domMap.visit(store, &remover);
    110         domMap.clear();
    111     }
    112 
    113 } // namespace WebCore
    114 
    115 #endif // DOMData_h
    116