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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/core/v8/V8Binding.h"
     35 #include "bindings/core/v8/V8EventListener.h"
     36 #include <v8.h>
     37 
     38 namespace blink {
     39 
     40 class LocalFrame;
     41 
     42 enum ListenerLookupType {
     43     ListenerFindOnly,
     44     ListenerFindOrCreate,
     45 };
     46 
     47 // This is a container for V8EventListener objects that uses hidden properties of v8::Object to speed up lookups.
     48 class V8EventListenerList {
     49 public:
     50     static PassRefPtr<V8EventListener> findWrapper(v8::Local<v8::Value> value, ScriptState* scriptState)
     51     {
     52         ASSERT(scriptState->isolate()->InContext());
     53         if (!value->IsObject())
     54             return nullptr;
     55 
     56         v8::Handle<v8::String> wrapperProperty = getHiddenProperty(false, scriptState->isolate());
     57         return doFindWrapper(v8::Local<v8::Object>::Cast(value), wrapperProperty, scriptState);
     58     }
     59 
     60     template<typename WrapperType>
     61     static PassRefPtr<V8EventListener> findOrCreateWrapper(v8::Local<v8::Value>, bool isAttribute, ScriptState*);
     62 
     63     static void clearWrapper(v8::Handle<v8::Object> listenerObject, bool isAttribute, v8::Isolate* isolate)
     64     {
     65         v8::Handle<v8::String> wrapperProperty = getHiddenProperty(isAttribute, isolate);
     66         listenerObject->DeleteHiddenValue(wrapperProperty);
     67     }
     68 
     69     static PassRefPtr<EventListener> getEventListener(ScriptState*, v8::Local<v8::Value>, bool isAttribute, ListenerLookupType);
     70 
     71 private:
     72     static V8EventListener* doFindWrapper(v8::Local<v8::Object> object, v8::Handle<v8::String> wrapperProperty, ScriptState* scriptState)
     73     {
     74         v8::HandleScope scope(scriptState->isolate());
     75         ASSERT(scriptState->isolate()->InContext());
     76         v8::Local<v8::Value> listener = object->GetHiddenValue(wrapperProperty);
     77         if (listener.IsEmpty())
     78             return 0;
     79         return static_cast<V8EventListener*>(v8::External::Cast(*listener)->Value());
     80     }
     81 
     82     static inline v8::Handle<v8::String> getHiddenProperty(bool isAttribute, v8::Isolate* isolate)
     83     {
     84         return isAttribute ? v8AtomicString(isolate, "attributeListener") : v8AtomicString(isolate, "listener");
     85     }
     86 };
     87 
     88 template<typename WrapperType>
     89 PassRefPtr<V8EventListener> V8EventListenerList::findOrCreateWrapper(v8::Local<v8::Value> value, bool isAttribute, ScriptState* scriptState)
     90 {
     91     v8::Isolate* isolate = scriptState->isolate();
     92     ASSERT(isolate->InContext());
     93     if (!value->IsObject()
     94         // Non-callable attribute setter input is treated as null (no wrapper)
     95         || (isAttribute && !value->IsFunction()))
     96         return nullptr;
     97 
     98     v8::Local<v8::Object> object = v8::Local<v8::Object>::Cast(value);
     99     v8::Handle<v8::String> wrapperProperty = getHiddenProperty(isAttribute, isolate);
    100 
    101     V8EventListener* wrapper = doFindWrapper(object, wrapperProperty, scriptState);
    102     if (wrapper)
    103         return wrapper;
    104 
    105     RefPtr<V8EventListener> wrapperPtr = WrapperType::create(object, isAttribute, scriptState);
    106     if (wrapperPtr)
    107         object->SetHiddenValue(wrapperProperty, v8::External::New(isolate, wrapperPtr.get()));
    108 
    109     return wrapperPtr;
    110 }
    111 
    112 } // namespace blink
    113 
    114 #endif // V8EventListenerList_h
    115