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 #include "config.h"
32 #include "bindings/v8/V8AbstractEventListener.h"
33
34 #include "V8Event.h"
35 #include "V8EventTarget.h"
36 #include "bindings/v8/V8Binding.h"
37 #include "bindings/v8/V8EventListenerList.h"
38 #include "bindings/v8/V8HiddenPropertyName.h"
39 #include "core/events/BeforeUnloadEvent.h"
40 #include "core/events/Event.h"
41 #include "core/events/ThreadLocalEventNames.h"
42 #include "core/inspector/InspectorCounters.h"
43 #include "core/workers/WorkerGlobalScope.h"
44
45 namespace WebCore {
46
V8AbstractEventListener(bool isAttribute,PassRefPtr<DOMWrapperWorld> world,v8::Isolate * isolate)47 V8AbstractEventListener::V8AbstractEventListener(bool isAttribute, PassRefPtr<DOMWrapperWorld> world, v8::Isolate* isolate)
48 : EventListener(JSEventListenerType)
49 , m_isAttribute(isAttribute)
50 , m_world(world)
51 , m_isolate(isolate)
52 {
53 if (isMainThread())
54 InspectorCounters::incrementCounter(InspectorCounters::JSEventListenerCounter);
55 }
56
~V8AbstractEventListener()57 V8AbstractEventListener::~V8AbstractEventListener()
58 {
59 if (!m_listener.isEmpty()) {
60 v8::HandleScope scope(m_isolate);
61 V8EventListenerList::clearWrapper(m_listener.newLocal(m_isolate), m_isAttribute, m_isolate);
62 }
63 if (isMainThread())
64 InspectorCounters::decrementCounter(InspectorCounters::JSEventListenerCounter);
65 }
66
handleEvent(ExecutionContext * context,Event * event)67 void V8AbstractEventListener::handleEvent(ExecutionContext* context, Event* event)
68 {
69 // Don't reenter V8 if execution was terminated in this instance of V8.
70 if (context->isJSExecutionForbidden())
71 return;
72
73 ASSERT(event);
74
75 // The callback function on XMLHttpRequest can clear the event listener and destroys 'this' object. Keep a local reference to it.
76 // See issue 889829.
77 RefPtr<V8AbstractEventListener> protect(this);
78
79 v8::HandleScope handleScope(m_isolate);
80
81 v8::Local<v8::Context> v8Context = toV8Context(context, world());
82 if (v8Context.IsEmpty())
83 return;
84
85 // Enter the V8 context in which to perform the event handling.
86 v8::Context::Scope scope(v8Context);
87
88 // Get the V8 wrapper for the event object.
89 v8::Isolate* isolate = v8Context->GetIsolate();
90 v8::Handle<v8::Value> jsEvent = toV8(event, v8::Handle<v8::Object>(), isolate);
91 if (jsEvent.IsEmpty())
92 return;
93 invokeEventHandler(context, event, v8::Local<v8::Value>::New(isolate, jsEvent));
94 }
95
setListenerObject(v8::Handle<v8::Object> listener)96 void V8AbstractEventListener::setListenerObject(v8::Handle<v8::Object> listener)
97 {
98 m_listener.set(m_isolate, listener);
99 m_listener.setWeak(this, &setWeakCallback);
100 }
101
invokeEventHandler(ExecutionContext * context,Event * event,v8::Local<v8::Value> jsEvent)102 void V8AbstractEventListener::invokeEventHandler(ExecutionContext* context, Event* event, v8::Local<v8::Value> jsEvent)
103 {
104 // If jsEvent is empty, attempt to set it as a hidden value would crash v8.
105 if (jsEvent.IsEmpty())
106 return;
107
108 v8::Local<v8::Context> v8Context = toV8Context(context, world());
109 if (v8Context.IsEmpty())
110 return;
111
112 // We push the event being processed into the global object, so that it can be exposed by DOMWindow's bindings.
113 v8::Handle<v8::String> eventSymbol = V8HiddenPropertyName::event(v8Context->GetIsolate());
114 v8::Local<v8::Value> returnValue;
115
116 {
117 // Catch exceptions thrown in the event handler so they do not propagate to javascript code that caused the event to fire.
118 v8::TryCatch tryCatch;
119 tryCatch.SetVerbose(true);
120
121 // Save the old 'event' property so we can restore it later.
122 v8::Local<v8::Value> savedEvent = v8Context->Global()->GetHiddenValue(eventSymbol);
123 tryCatch.Reset();
124
125 // Make the event available in the global object, so DOMWindow can expose it.
126 v8Context->Global()->SetHiddenValue(eventSymbol, jsEvent);
127 tryCatch.Reset();
128
129 returnValue = callListenerFunction(context, jsEvent, event);
130 if (tryCatch.HasCaught())
131 event->target()->uncaughtExceptionInEventHandler();
132
133 if (!tryCatch.CanContinue()) { // Result of TerminateExecution().
134 if (context->isWorkerGlobalScope())
135 toWorkerGlobalScope(context)->script()->forbidExecution();
136 return;
137 }
138 tryCatch.Reset();
139
140 // Restore the old event. This must be done for all exit paths through this method.
141 if (savedEvent.IsEmpty())
142 v8Context->Global()->SetHiddenValue(eventSymbol, v8::Undefined(v8Context->GetIsolate()));
143 else
144 v8Context->Global()->SetHiddenValue(eventSymbol, savedEvent);
145 tryCatch.Reset();
146 }
147
148 ASSERT(!handleOutOfMemory() || returnValue.IsEmpty());
149
150 if (returnValue.IsEmpty())
151 return;
152
153 if (!returnValue->IsNull() && !returnValue->IsUndefined() && event->isBeforeUnloadEvent()) {
154 V8TRYCATCH_FOR_V8STRINGRESOURCE_VOID(V8StringResource<>, stringReturnValue, returnValue);
155 toBeforeUnloadEvent(event)->setReturnValue(stringReturnValue);
156 }
157
158 if (m_isAttribute && shouldPreventDefault(returnValue))
159 event->preventDefault();
160 }
161
shouldPreventDefault(v8::Local<v8::Value> returnValue)162 bool V8AbstractEventListener::shouldPreventDefault(v8::Local<v8::Value> returnValue)
163 {
164 // Prevent default action if the return value is false in accord with the spec
165 // http://www.w3.org/TR/html5/webappapis.html#event-handler-attributes
166 return returnValue->IsBoolean() && !returnValue->BooleanValue();
167 }
168
getReceiverObject(ExecutionContext * context,Event * event)169 v8::Local<v8::Object> V8AbstractEventListener::getReceiverObject(ExecutionContext* context, Event* event)
170 {
171 v8::Isolate* isolate = toV8Context(context, world())->GetIsolate();
172 v8::Local<v8::Object> listener = m_listener.newLocal(isolate);
173 if (!m_listener.isEmpty() && !listener->IsFunction())
174 return listener;
175
176 EventTarget* target = event->currentTarget();
177 v8::Handle<v8::Value> value = toV8(target, v8::Handle<v8::Object>(), isolate);
178 if (value.IsEmpty())
179 return v8::Local<v8::Object>();
180 return v8::Local<v8::Object>::New(isolate, v8::Handle<v8::Object>::Cast(value));
181 }
182
setWeakCallback(const v8::WeakCallbackData<v8::Object,V8AbstractEventListener> & data)183 void V8AbstractEventListener::setWeakCallback(const v8::WeakCallbackData<v8::Object, V8AbstractEventListener> &data)
184 {
185 data.GetParameter()->m_listener.clear();
186 }
187
188 } // namespace WebCore
189