/*

 * 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