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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 V8EventListenerList_h
     32 #define V8EventListenerList_h
     33 
     34 #include "bindings/v8/V8EventListener.h"
     35 #include "bindings/v8/V8HiddenPropertyName.h"
     36 
     37 #include <v8.h>
     38 #include "wtf/PassRefPtr.h"
     39 
     40 namespace WebCore {
     41 
     42 class Frame;
     43 
     44 enum ListenerLookupType {
     45     ListenerFindOnly,
     46     ListenerFindOrCreate,
     47 };
     48 
     49 // This is a container for V8EventListener objects that uses hidden properties of v8::Object to speed up lookups.
     50 class V8EventListenerList {
     51 public:
     52     static PassRefPtr<V8EventListener> findWrapper(v8::Local<v8::Value> value, v8::Isolate* isolate)
     53     {
     54         ASSERT(isolate->InContext());
     55         if (!value->IsObject())
     56             return 0;
     57 
     58         v8::Handle<v8::String> wrapperProperty = getHiddenProperty(false, isolate);
     59         return doFindWrapper(v8::Local<v8::Object>::Cast(value), wrapperProperty, isolate);
     60     }
     61 
     62     template<typename WrapperType>
     63     static PassRefPtr<V8EventListener> findOrCreateWrapper(v8::Local<v8::Value>, bool isAttribute, v8::Isolate*);
     64 
     65     static void clearWrapper(v8::Handle<v8::Object> listenerObject, bool isAttribute, v8::Isolate* isolate)
     66     {
     67         v8::Handle<v8::String> wrapperProperty = getHiddenProperty(isAttribute, isolate);
     68         listenerObject->DeleteHiddenValue(wrapperProperty);
     69     }
     70 
     71     static PassRefPtr<EventListener> getEventListener(v8::Local<v8::Value>, bool isAttribute, ListenerLookupType);
     72 
     73 private:
     74     static V8EventListener* doFindWrapper(v8::Local<v8::Object> object, v8::Handle<v8::String> wrapperProperty, v8::Isolate* isolate)
     75     {
     76         ASSERT(isolate->InContext());
     77         v8::HandleScope scope(isolate);
     78         v8::Local<v8::Value> listener = object->GetHiddenValue(wrapperProperty);
     79         if (listener.IsEmpty())
     80             return 0;
     81         return static_cast<V8EventListener*>(v8::External::Cast(*listener)->Value());
     82     }
     83 
     84     static inline v8::Handle<v8::String> getHiddenProperty(bool isAttribute, v8::Isolate* isolate)
     85     {
     86         return isAttribute ? V8HiddenPropertyName::attributeListener(isolate) : V8HiddenPropertyName::listener(isolate);
     87     }
     88 };
     89 
     90 template<typename WrapperType>
     91 PassRefPtr<V8EventListener> V8EventListenerList::findOrCreateWrapper(v8::Local<v8::Value> value, bool isAttribute, v8::Isolate* isolate)
     92 {
     93     ASSERT(isolate->InContext());
     94     if (!value->IsObject()
     95         // Non-callable attribute setter input is treated as null (no wrapper)
     96         || (isAttribute && !value->IsFunction()))
     97         return 0;
     98 
     99     v8::Local<v8::Object> object = v8::Local<v8::Object>::Cast(value);
    100     v8::Handle<v8::String> wrapperProperty = getHiddenProperty(isAttribute, isolate);
    101 
    102     V8EventListener* wrapper = doFindWrapper(object, wrapperProperty, isolate);
    103     if (wrapper)
    104         return wrapper;
    105 
    106     RefPtr<V8EventListener> wrapperPtr = WrapperType::create(object, isAttribute, isolate);
    107     if (wrapperPtr)
    108         object->SetHiddenValue(wrapperProperty, v8::External::New(isolate, wrapperPtr.get()));
    109 
    110     return wrapperPtr;
    111 }
    112 
    113 } // namespace WebCore
    114 
    115 #endif // V8EventListenerList_h
    116