ScriptVal.h

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/* Copyright (C) 2010 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef INCLUDED_SCRIPTVAL
#define INCLUDED_SCRIPTVAL

#include "ScriptTypes.h"
#include <boost/shared_ptr.hpp>

/**
 * A trivial wrapper around a jsval. Used to avoid template overload ambiguities
 * with jsval (which is just an integer), for any code that uses
 * ScriptInterface::ToJSVal or ScriptInterface::FromJSVal
 */
class CScriptVal
{
public:
    CScriptVal() : m_Val(JSVAL_VOID) { }
    CScriptVal(jsval val) : m_Val(val) { }

    /**
     * Returns the current value.
     */
    const jsval& get() const { return m_Val; }

    /**
     * Returns whether the value is JSVAL_VOID.
     */
    bool undefined() const { return JSVAL_IS_VOID(m_Val) ? true : false; }

private:
    jsval m_Val;
};

class CScriptValRooted
{
public:
    CScriptValRooted() { }
    CScriptValRooted(JSContext* cx, jsval val);
    CScriptValRooted(JSContext* cx, CScriptVal val);

    /**
     * Returns the current value (or JSVAL_VOID if uninitialised).
     */
    jsval get() const;

    /**
     * Returns reference to the current value.
     * Fails if the value is not yet initialised.
     */
    jsval& getRef() const;

    /**
     * Returns whether the value is uninitialised or is JSVAL_VOID.
     */
    bool undefined() const;

    /**
     * Returns whether the value is uninitialised.
     */
    bool uninitialised() const;

private:
    boost::shared_ptr<jsval> m_Val;
};

/**
 * RAII wrapper for JSIdArray*
 */
class AutoJSIdArray
{
    NONCOPYABLE(AutoJSIdArray);
public:
    AutoJSIdArray(JSContext* cx, JSIdArray* ida);
    ~AutoJSIdArray();

    JSIdArray* get() const;
    size_t length() const;
    jsid operator[](size_t i) const;

private:
    JSContext* m_Context;
    JSIdArray* m_IdArray;
};

#endif // INCLUDED_SCRIPTVAL