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. 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 V8AbstractEventListener_h 32 #define V8AbstractEventListener_h 33 34 #include "bindings/v8/DOMWrapperWorld.h" 35 #include "bindings/v8/ScopedPersistent.h" 36 #include "bindings/v8/V8Utilities.h" 37 #include "core/events/EventListener.h" 38 #include <v8.h> 39 #include "wtf/PassRefPtr.h" 40 #include "wtf/RefCounted.h" 41 42 namespace WebCore { 43 44 class Event; 45 46 // There are two kinds of event listeners: HTML or non-HMTL. onload, 47 // onfocus, etc (attributes) are always HTML event handler type; Event 48 // listeners added by Window.addEventListener or 49 // EventTargetNode::addEventListener are non-HTML type. 50 // 51 // Why does this matter? 52 // WebKit does not allow duplicated HTML event handlers of the same type, 53 // but ALLOWs duplicated non-HTML event handlers. 54 class V8AbstractEventListener : public EventListener { 55 public: 56 virtual ~V8AbstractEventListener(); 57 cast(const EventListener * listener)58 static const V8AbstractEventListener* cast(const EventListener* listener) 59 { 60 return listener->type() == JSEventListenerType 61 ? static_cast<const V8AbstractEventListener*>(listener) 62 : 0; 63 } 64 cast(EventListener * listener)65 static V8AbstractEventListener* cast(EventListener* listener) 66 { 67 return const_cast<V8AbstractEventListener*>(cast(const_cast<const EventListener*>(listener))); 68 } 69 70 // Implementation of EventListener interface. 71 72 virtual bool operator==(const EventListener& other) { return this == &other; } 73 74 virtual void handleEvent(ExecutionContext*, Event*); 75 isLazy()76 virtual bool isLazy() const { return false; } 77 78 // Returns the listener object, either a function or an object. getListenerObject(ExecutionContext * context)79 v8::Local<v8::Object> getListenerObject(ExecutionContext* context) 80 { 81 // prepareListenerObject can potentially deref this event listener 82 // as it may attempt to compile a function (lazy event listener), get an error 83 // and invoke onerror callback which can execute arbitrary JS code. 84 // Protect this event listener to keep it alive. 85 RefPtr<V8AbstractEventListener> guard(this); 86 prepareListenerObject(context); 87 return m_listener.newLocal(m_isolate); 88 } 89 getExistingListenerObject()90 v8::Local<v8::Object> getExistingListenerObject() 91 { 92 return m_listener.newLocal(m_isolate); 93 } 94 95 // Provides access to the underlying handle for GC. Returned 96 // value is a weak handle and so not guaranteed to stay alive. existingListenerObjectPersistentHandle()97 v8::Persistent<v8::Object>& existingListenerObjectPersistentHandle() 98 { 99 return m_listener.getUnsafe(); 100 } 101 hasExistingListenerObject()102 bool hasExistingListenerObject() 103 { 104 return !m_listener.isEmpty(); 105 } 106 clearListenerObject()107 void clearListenerObject() 108 { 109 m_listener.clear(); 110 } 111 world()112 virtual DOMWrapperWorld* world() const OVERRIDE FINAL { return m_world.get(); } isolate()113 v8::Isolate* isolate() const { return m_isolate; } 114 115 protected: 116 V8AbstractEventListener(bool isAttribute, PassRefPtr<DOMWrapperWorld>, v8::Isolate*); 117 prepareListenerObject(ExecutionContext *)118 virtual void prepareListenerObject(ExecutionContext*) { } 119 120 void setListenerObject(v8::Handle<v8::Object> listener); 121 122 void invokeEventHandler(ExecutionContext*, Event*, v8::Local<v8::Value> jsEvent); 123 124 // Get the receiver object to use for event listener call. 125 v8::Local<v8::Object> getReceiverObject(ExecutionContext*, Event*); 126 127 private: 128 // Implementation of EventListener function. virtualisAttribute()129 virtual bool virtualisAttribute() const { return m_isAttribute; } 130 131 virtual v8::Local<v8::Value> callListenerFunction(ExecutionContext*, v8::Handle<v8::Value> jsevent, Event*) = 0; 132 133 virtual bool shouldPreventDefault(v8::Local<v8::Value> returnValue); 134 135 static void setWeakCallback(const v8::WeakCallbackData<v8::Object, V8AbstractEventListener>&); 136 137 ScopedPersistent<v8::Object> m_listener; 138 139 // Indicates if this is an HTML type listener. 140 bool m_isAttribute; 141 142 RefPtr<DOMWrapperWorld> m_world; 143 v8::Isolate* m_isolate; 144 }; 145 146 } // namespace WebCore 147 148 #endif // V8AbstractEventListener_h 149