/*
 * Copyright (C) 2008, 2009 Google 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:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "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 THE COPYRIGHT
 * OWNER 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.
 */

#ifndef ScriptState_h
#define ScriptState_h

#include "DOMWrapperWorld.h"
#include <v8.h>
#include <wtf/Noncopyable.h>
#include <wtf/RefCounted.h>

namespace WebCore {
class DOMWrapperWorld;
class Frame;
class Node;
class Page;

class ScriptState : public Noncopyable {
public:
    bool hadException() { return !m_exception.IsEmpty(); }
    void setException(v8::Local<v8::Value> exception)
    {
        m_exception = exception;
    }
    v8::Local<v8::Value> exception() { return m_exception; }

    v8::Local<v8::Context> context() const
    {
        return v8::Local<v8::Context>::New(m_context);
    }

    static ScriptState* forContext(v8::Local<v8::Context>);
    static ScriptState* current();

protected:
    ScriptState() { }
    ~ScriptState();

private:
    friend ScriptState* mainWorldScriptState(Frame*);
    explicit ScriptState(v8::Handle<v8::Context>);

    static void weakReferenceCallback(v8::Persistent<v8::Value> object, void* parameter);

    v8::Local<v8::Value> m_exception;
    v8::Persistent<v8::Context> m_context;
};

class EmptyScriptState : public ScriptState {
public:
    EmptyScriptState() : ScriptState() { }
    ~EmptyScriptState() { }
};

class ScriptStateProtectedPtr : public Noncopyable {
public:
    ScriptStateProtectedPtr() : m_scriptState(0) { }
    ScriptStateProtectedPtr(ScriptState* scriptState) : m_scriptState(scriptState)
    {
        v8::HandleScope handleScope;
        // Keep the context from being GC'ed. ScriptState is guaranteed to be live while the context is live.
        m_context = v8::Persistent<v8::Context>::New(scriptState->context());
    }
    ~ScriptStateProtectedPtr()
    {
        if (!m_context.IsEmpty()) {
            m_context.Dispose();
            m_context.Clear();
        }
    }
    ScriptState* get() { return m_scriptState; }
private:
    ScriptState* m_scriptState;
    v8::Persistent<v8::Context> m_context;
};

ScriptState* mainWorldScriptState(Frame*);

ScriptState* scriptStateFromNode(DOMWrapperWorld*, Node*);
ScriptState* scriptStateFromPage(DOMWrapperWorld*, Page*);

inline DOMWrapperWorld* debuggerWorld() { return mainThreadNormalWorld(); }
inline DOMWrapperWorld* pluginWorld() { return mainThreadNormalWorld(); }

}

#endif // ScriptState_h
