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      1 /*
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     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef V8AbstractEventListener_h
     32 #define V8AbstractEventListener_h
     33 
     34 #include "EventListener.h"
     35 #include "WorldContextHandle.h"
     36 
     37 #include <v8.h>
     38 #include <wtf/PassRefPtr.h>
     39 #include <wtf/RefCounted.h>
     40 
     41 namespace WebCore {
     42 
     43     class Event;
     44     class Frame;
     45     class V8Proxy;
     46 
     47     // There are two kinds of event listeners: HTML or non-HMTL. onload,
     48     // onfocus, etc (attributes) are always HTML event handler type; Event
     49     // listeners added by Window.addEventListener or
     50     // EventTargetNode::addEventListener are non-HTML type.
     51     //
     52     // Why does this matter?
     53     // WebKit does not allow duplicated HTML event handlers of the same type,
     54     // but ALLOWs duplicated non-HTML event handlers.
     55     class V8AbstractEventListener : public EventListener {
     56     public:
     57         virtual ~V8AbstractEventListener();
     58 
     59         static const V8AbstractEventListener* cast(const EventListener* listener)
     60         {
     61             return listener->type() == JSEventListenerType
     62                 ? static_cast<const V8AbstractEventListener*>(listener)
     63                 : 0;
     64         }
     65 
     66         static V8AbstractEventListener* cast(EventListener* listener)
     67         {
     68             return const_cast<V8AbstractEventListener*>(cast(const_cast<const EventListener*>(listener)));
     69         }
     70 
     71         // Implementation of EventListener interface.
     72 
     73         virtual bool operator==(const EventListener& other) { return this == &other; }
     74 
     75         virtual void handleEvent(ScriptExecutionContext*, Event*);
     76 
     77         virtual bool isLazy() const { return false; }
     78 
     79         // Returns the listener object, either a function or an object.
     80         v8::Local<v8::Object> getListenerObject(ScriptExecutionContext* context)
     81         {
     82             prepareListenerObject(context);
     83             return v8::Local<v8::Object>::New(m_listener);
     84         }
     85 
     86         v8::Local<v8::Object> getExistingListenerObject()
     87         {
     88             return v8::Local<v8::Object>::New(m_listener);
     89         }
     90 
     91         bool hasExistingListenerObject()
     92         {
     93             return !m_listener.IsEmpty();
     94         }
     95 
     96         // Dispose listener object and clear the handle.
     97         void disposeListenerObject();
     98 
     99         const WorldContextHandle& worldContext() const { return m_worldContext; }
    100 
    101     protected:
    102         V8AbstractEventListener(bool isAttribute, const WorldContextHandle& worldContext);
    103 
    104         virtual void prepareListenerObject(ScriptExecutionContext*) { }
    105 
    106         void setListenerObject(v8::Handle<v8::Object> listener);
    107 
    108         void invokeEventHandler(ScriptExecutionContext*, Event*, v8::Handle<v8::Value> jsEvent);
    109 
    110         // Get the receiver object to use for event listener call.
    111         v8::Local<v8::Object> getReceiverObject(Event*);
    112 
    113     private:
    114         // Implementation of EventListener function.
    115         virtual bool virtualisAttribute() const { return m_isAttribute; }
    116 
    117         virtual v8::Local<v8::Value> callListenerFunction(ScriptExecutionContext*, v8::Handle<v8::Value> jsevent, Event*) = 0;
    118 
    119         v8::Persistent<v8::Object> m_listener;
    120 
    121         // Indicates if the above handle is weak.
    122         bool m_isWeak;
    123 
    124         // Indicates if this is an HTML type listener.
    125         bool m_isAttribute;
    126 
    127         WorldContextHandle m_worldContext;
    128     };
    129 
    130 } // namespace WebCore
    131 
    132 #endif // V8AbstractEventListener_h
    133