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/platform/external/webkit/WebCore/bindings/v8/V8AbstractEventListener.cpp

https://github.com/aharish/totoro-gb-opensource-update2
C++ | 193 lines | 117 code | 33 blank | 43 comment | 27 complexity | 8998babe967c3b1e6491cec3dd9ff2d2 MD5 | raw file
  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 "V8AbstractEventListener.h"
 33
 34#include "DateExtension.h"
 35#include "Document.h"
 36#include "Event.h"
 37#include "Frame.h"
 38#include "V8Binding.h"
 39#include "V8Event.h"
 40#include "V8EventListenerList.h"
 41#include "V8Proxy.h"
 42#include "V8Utilities.h"
 43#include "WorkerContext.h"
 44#include "WorkerContextExecutionProxy.h"
 45
 46namespace WebCore {
 47
 48static void weakEventListenerCallback(v8::Persistent<v8::Value>, void* parameter)
 49{
 50    V8AbstractEventListener* listener = static_cast<V8AbstractEventListener*>(parameter);
 51    listener->disposeListenerObject();
 52}
 53
 54V8AbstractEventListener::V8AbstractEventListener(bool isAttribute, const WorldContextHandle& worldContext)
 55    : EventListener(JSEventListenerType)
 56    , m_isWeak(true)
 57    , m_isAttribute(isAttribute)
 58    , m_worldContext(worldContext)
 59{
 60}
 61
 62V8AbstractEventListener::~V8AbstractEventListener()
 63{
 64    if (!m_listener.IsEmpty()) {
 65        v8::HandleScope scope;
 66        v8::Local<v8::Object> listener = v8::Local<v8::Object>::New(m_listener);
 67        V8EventListenerList::clearWrapper(listener, m_isAttribute);
 68    }
 69    disposeListenerObject();
 70}
 71
 72void V8AbstractEventListener::handleEvent(ScriptExecutionContext* context, Event* event)
 73{
 74    // The callback function on XMLHttpRequest can clear the event listener and destroys 'this' object. Keep a local reference to it.
 75    // See issue 889829.
 76    RefPtr<V8AbstractEventListener> protect(this);
 77
 78    v8::HandleScope handleScope;
 79
 80    v8::Local<v8::Context> v8Context = toV8Context(context, worldContext());
 81    if (v8Context.IsEmpty())
 82        return;
 83
 84    // Enter the V8 context in which to perform the event handling.
 85    v8::Context::Scope scope(v8Context);
 86
 87    // Get the V8 wrapper for the event object.
 88    v8::Handle<v8::Value> jsEvent = toV8(event);
 89
 90    invokeEventHandler(context, event, jsEvent);
 91
 92    Document::updateStyleForAllDocuments();
 93}
 94
 95void V8AbstractEventListener::disposeListenerObject()
 96{
 97    if (!m_listener.IsEmpty()) {
 98#ifndef NDEBUG
 99        V8GCController::unregisterGlobalHandle(this, m_listener);
100#endif
101        m_listener.Dispose();
102        m_listener.Clear();
103    }
104}
105
106void V8AbstractEventListener::setListenerObject(v8::Handle<v8::Object> listener)
107{
108    disposeListenerObject();
109    m_listener = v8::Persistent<v8::Object>::New(listener);
110#ifndef NDEBUG
111    V8GCController::registerGlobalHandle(EVENT_LISTENER, this, m_listener);
112#endif
113    if (m_isWeak)
114        m_listener.MakeWeak(this, &weakEventListenerCallback);
115}
116
117void V8AbstractEventListener::invokeEventHandler(ScriptExecutionContext* context, Event* event, v8::Handle<v8::Value> jsEvent)
118{
119
120    v8::Local<v8::Context> v8Context = toV8Context(context, worldContext());
121    if (v8Context.IsEmpty())
122        return;
123
124    // We push the event being processed into the global object, so that it can be exposed by DOMWindow's bindings.
125    v8::Local<v8::String> eventSymbol = v8::String::NewSymbol("event");
126    v8::Local<v8::Value> returnValue;
127
128    // In beforeunload/unload handlers, we want to avoid sleeps which do tight loops of calling Date.getTime().
129    if (event->type() == "beforeunload" || event->type() == "unload")
130        DateExtension::get()->setAllowSleep(false);
131
132    {
133        // Catch exceptions thrown in the event handler so they do not propagate to javascript code that caused the event to fire.
134        v8::TryCatch tryCatch;
135        tryCatch.SetVerbose(true);
136
137        // Save the old 'event' property so we can restore it later.
138        v8::Local<v8::Value> savedEvent = v8Context->Global()->GetHiddenValue(eventSymbol);
139        tryCatch.Reset();
140
141        // Make the event available in the global object, so DOMWindow can expose it.
142        v8Context->Global()->SetHiddenValue(eventSymbol, jsEvent);
143        tryCatch.Reset();
144
145        // Call the event handler.
146        returnValue = callListenerFunction(context, jsEvent, event);
147        if (!tryCatch.CanContinue())
148            return;
149
150        // If an error occurs while handling the event, it should be reported.
151        if (tryCatch.HasCaught()) {
152            reportException(0, tryCatch);
153            tryCatch.Reset();
154        }
155
156        // Restore the old event. This must be done for all exit paths through this method.
157        if (savedEvent.IsEmpty())
158            v8Context->Global()->SetHiddenValue(eventSymbol, v8::Undefined());
159        else
160            v8Context->Global()->SetHiddenValue(eventSymbol, savedEvent);
161        tryCatch.Reset();
162    }
163
164    if (event->type() == "beforeunload" || event->type() == "unload")
165        DateExtension::get()->setAllowSleep(true);
166
167    ASSERT(!V8Proxy::handleOutOfMemory() || returnValue.IsEmpty());
168
169    if (returnValue.IsEmpty())
170        return;
171
172    if (!returnValue->IsNull() && !returnValue->IsUndefined() && event->storesResultAsString())
173        event->storeResult(toWebCoreString(returnValue));
174
175    // Prevent default action if the return value is false;
176    // FIXME: Add example, and reference to bug entry.
177    if (m_isAttribute && returnValue->IsBoolean() && !returnValue->BooleanValue())
178        event->preventDefault();
179}
180
181v8::Local<v8::Object> V8AbstractEventListener::getReceiverObject(Event* event)
182{
183    if (!m_listener.IsEmpty() && !m_listener->IsFunction())
184        return v8::Local<v8::Object>::New(m_listener);
185
186    EventTarget* target = event->currentTarget();
187    v8::Handle<v8::Value> value = V8DOMWrapper::convertEventTargetToV8Object(target);
188    if (value.IsEmpty())
189        return v8::Local<v8::Object>();
190    return v8::Local<v8::Object>::New(v8::Handle<v8::Object>::Cast(value));
191}
192
193} // namespace WebCore