1/*
2 * Copyright (C) 2006, 2007, 2008, 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.
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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,
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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
41namespace 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