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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 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 DOMWrapperMap_h
     32 #define DOMWrapperMap_h
     33 
     34 #include "bindings/v8/UnsafePersistent.h"
     35 #include "bindings/v8/V8Utilities.h"
     36 #include "bindings/v8/WrapperTypeInfo.h"
     37 #include <v8.h>
     38 #include "wtf/HashMap.h"
     39 
     40 namespace WebCore {
     41 
     42 template<class KeyType>
     43 class DOMWrapperMap {
     44 public:
     45     typedef HashMap<KeyType*, UnsafePersistent<v8::Object> > MapType;
     46 
     47     explicit DOMWrapperMap(v8::Isolate* isolate)
     48         : m_isolate(isolate)
     49     {
     50     }
     51 
     52     v8::Handle<v8::Object> get(KeyType* key)
     53     {
     54         return m_map.get(key).deprecatedHandle();
     55     }
     56 
     57     v8::Handle<v8::Object> getNewLocal(v8::Isolate* isolate, KeyType* key)
     58     {
     59         return m_map.get(key).newLocal(isolate);
     60     }
     61 
     62     void set(KeyType* key, v8::Handle<v8::Object> wrapper, const WrapperConfiguration& configuration)
     63     {
     64         ASSERT(static_cast<KeyType*>(toNative(wrapper)) == key);
     65         v8::Persistent<v8::Object> persistent(m_isolate, wrapper);
     66         configuration.configureWrapper(&persistent, m_isolate);
     67         persistent.MakeWeak(this, &makeWeakCallback);
     68         typename MapType::AddResult result = m_map.add(key, UnsafePersistent<v8::Object>());
     69         ASSERT(result.isNewEntry);
     70         // FIXME: Stop handling this case once duplicate wrappers are guaranteed not to be created.
     71         if (!result.isNewEntry)
     72             result.iterator->value.dispose();
     73         result.iterator->value = UnsafePersistent<v8::Object>(persistent);
     74     }
     75 
     76     void clear()
     77     {
     78         while (!m_map.isEmpty()) {
     79             // Swap out m_map on each iteration to ensure any wrappers added due to side effects of the loop are cleared.
     80             MapType map;
     81             map.swap(m_map);
     82             for (typename MapType::iterator it = map.begin(); it != map.end(); ++it) {
     83                 toWrapperTypeInfo(it->value.deprecatedHandle())->derefObject(it->key);
     84                 it->value.dispose();
     85             }
     86         }
     87     }
     88 
     89     void removeAndDispose(KeyType* key)
     90     {
     91         typename MapType::iterator it = m_map.find(key);
     92         ASSERT(it != m_map.end());
     93         it->value.dispose();
     94         m_map.remove(it);
     95     }
     96 
     97 private:
     98     static void makeWeakCallback(v8::Isolate*, v8::Persistent<v8::Object>* wrapper, DOMWrapperMap<KeyType>*);
     99 
    100     v8::Isolate* m_isolate;
    101     MapType m_map;
    102 };
    103 
    104 template<>
    105 inline void DOMWrapperMap<void>::makeWeakCallback(v8::Isolate* isolate, v8::Persistent<v8::Object>* wrapper, DOMWrapperMap<void>* map)
    106 {
    107     WrapperTypeInfo* type = toWrapperTypeInfo(*wrapper);
    108     ASSERT(type->derefObjectFunction);
    109     void* key = static_cast<void*>(toNative(*wrapper));
    110     ASSERT(map->get(key) == *wrapper);
    111     map->removeAndDispose(key);
    112     type->derefObject(key);
    113 }
    114 
    115 } // namespace WebCore
    116 
    117 #endif // DOMWrapperMap_h
    118