diff -r 000000000000 -r 4f2f89ce4247 WebCore/bridge/runtime_root.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/bridge/runtime_root.cpp	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,187 @@
+/*
+ * Copyright (C) 2004 Apple Computer, Inc.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#include "config.h"
+#include "runtime_root.h"
+
+#include "Bridge.h"
+#include "runtime_object.h"
+#include <runtime/JSGlobalObject.h>
+#include <wtf/HashCountedSet.h>
+#include <wtf/HashSet.h>
+#include <wtf/StdLibExtras.h>
+
+namespace JSC { namespace Bindings {
+
+// This code attempts to solve two problems: (1) plug-ins leaking references to 
+// JS and the DOM; (2) plug-ins holding stale references to JS and the DOM. Previous 
+// comments in this file claimed that problem #1 was an issue in Java, in particular, 
+// because Java, allegedly, didn't always call finalize when collecting an object.
+
+typedef HashSet<RootObject*> RootObjectSet;
+
+static RootObjectSet* rootObjectSet()
+{
+    DEFINE_STATIC_LOCAL(RootObjectSet, staticRootObjectSet, ());
+    return &staticRootObjectSet;
+}
+
+// FIXME:  These two functions are a potential performance problem.  We could 
+// fix them by adding a JSObject to RootObject dictionary.
+
+RootObject* findProtectingRootObject(JSObject* jsObject)
+{
+    RootObjectSet::const_iterator end = rootObjectSet()->end();
+    for (RootObjectSet::const_iterator it = rootObjectSet()->begin(); it != end; ++it) {
+        if ((*it)->gcIsProtected(jsObject))
+            return *it;
+    }
+    return 0;
+}
+
+RootObject* findRootObject(JSGlobalObject* globalObject)
+{
+    RootObjectSet::const_iterator end = rootObjectSet()->end();
+    for (RootObjectSet::const_iterator it = rootObjectSet()->begin(); it != end; ++it) {
+        if ((*it)->globalObject() == globalObject)
+            return *it;
+    }
+    return 0;
+}
+
+RootObject::InvalidationCallback::~InvalidationCallback()
+{
+}
+
+PassRefPtr<RootObject> RootObject::create(const void* nativeHandle, JSGlobalObject* globalObject)
+{
+    return adoptRef(new RootObject(nativeHandle, globalObject));
+}
+
+RootObject::RootObject(const void* nativeHandle, JSGlobalObject* globalObject)
+    : m_isValid(true)
+    , m_nativeHandle(nativeHandle)
+    , m_globalObject(globalObject)
+{
+    ASSERT(globalObject);
+    rootObjectSet()->add(this);
+}
+
+RootObject::~RootObject()
+{
+    if (m_isValid)
+        invalidate();
+}
+
+void RootObject::invalidate()
+{
+    if (!m_isValid)
+        return;
+
+    {
+        HashSet<RuntimeObject*>::iterator end = m_runtimeObjects.end();
+        for (HashSet<RuntimeObject*>::iterator it = m_runtimeObjects.begin(); it != end; ++it)
+            (*it)->invalidate();
+        
+        m_runtimeObjects.clear();
+    }
+    
+    m_isValid = false;
+
+    m_nativeHandle = 0;
+    m_globalObject = 0;
+
+    {
+        HashSet<InvalidationCallback*>::iterator end = m_invalidationCallbacks.end();
+        for (HashSet<InvalidationCallback*>::iterator iter = m_invalidationCallbacks.begin(); iter != end; ++iter)
+            (**iter)(this);
+
+        m_invalidationCallbacks.clear();
+    }
+
+    ProtectCountSet::iterator end = m_protectCountSet.end();
+    for (ProtectCountSet::iterator it = m_protectCountSet.begin(); it != end; ++it)
+        JSC::gcUnprotect(it->first);
+    m_protectCountSet.clear();
+
+    rootObjectSet()->remove(this);
+}
+
+void RootObject::gcProtect(JSObject* jsObject)
+{
+    ASSERT(m_isValid);
+    
+    if (!m_protectCountSet.contains(jsObject))
+        JSC::gcProtect(jsObject);
+    m_protectCountSet.add(jsObject);
+}
+
+void RootObject::gcUnprotect(JSObject* jsObject)
+{
+    ASSERT(m_isValid);
+    
+    if (!jsObject)
+        return;
+
+    if (m_protectCountSet.count(jsObject) == 1)
+        JSC::gcUnprotect(jsObject);
+    m_protectCountSet.remove(jsObject);
+}
+
+bool RootObject::gcIsProtected(JSObject* jsObject)
+{
+    ASSERT(m_isValid);
+    return m_protectCountSet.contains(jsObject);
+}
+
+const void* RootObject::nativeHandle() const 
+{ 
+    ASSERT(m_isValid);
+    return m_nativeHandle; 
+}
+
+JSGlobalObject* RootObject::globalObject() const
+{
+    ASSERT(m_isValid);
+    return m_globalObject;
+}
+
+void RootObject::addRuntimeObject(RuntimeObject* object)
+{
+    ASSERT(m_isValid);
+    ASSERT(!m_runtimeObjects.contains(object));
+    
+    m_runtimeObjects.add(object);
+}        
+    
+void RootObject::removeRuntimeObject(RuntimeObject* object)
+{
+    ASSERT(m_isValid);
+    ASSERT(m_runtimeObjects.contains(object));
+    
+    m_runtimeObjects.remove(object);
+}
+
+} } // namespace JSC::Bindings