/*

 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.nashorn.internal.runtime;

import static jdk.nashorn.internal.lookup.Lookup.MH;

import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;

import java.lang.invoke.MethodHandle;

import java.lang.invoke.MethodHandles;

import java.util.ArrayList;

import jdk.nashorn.internal.objects.Global;

/**

 * Instances of this class serve as "prototype" object for script functions.

 * The purpose is to expose "constructor" property from "prototype". Also, nasgen

 * generated prototype classes extend from this class.

 */

public class PrototypeObject extends ScriptObject {

    private static final PropertyMap map$;

    private Object constructor;

    private static final MethodHandle GET_CONSTRUCTOR = findOwnMH("getConstructor", Object.class, Object.class);

    private static final MethodHandle SET_CONSTRUCTOR = findOwnMH("setConstructor", void.class, Object.class, Object.class);

    static {

        final ArrayList<Property> properties = new ArrayList<>(1);

        properties.add(AccessorProperty.create("constructor", Property.NOT_ENUMERABLE, GET_CONSTRUCTOR, SET_CONSTRUCTOR));

        map$ = PropertyMap.newMap(properties);

    }

    private PrototypeObject(final Global global, final PropertyMap map) {

        super(global.getObjectPrototype(), map != map$? map.addAll(map$) : map$);

    }

    /**

     * Prototype constructor

     */

    protected PrototypeObject() {

        this(Global.instance(), map$);

    }

    /**

     * PropertyObject constructor

     *

     * @param map property map

     */

    protected PrototypeObject(final PropertyMap map) {

        this(Global.instance(), map);

    }

    /**

     * PropertyObject constructor

     *

     * @param func constructor function

     */

    protected PrototypeObject(final ScriptFunction func) {

        this(Global.instance(), map$);

        this.constructor = func;

    }

    /**

     * Get the constructor for this {@code PrototypeObject}

     * @param self self reference

     * @return constructor, probably, but not necessarily, a {@link ScriptFunction}

     */

    public static Object getConstructor(final Object self) {

        return (self instanceof PrototypeObject) ?

            ((PrototypeObject)self).getConstructor() :

            UNDEFINED;

    }

    /**

     * Reset the constructor for this {@code PrototypeObject}

     * @param self self reference

     * @param constructor constructor, probably, but not necessarily, a {@link ScriptFunction}

     */

    public static void setConstructor(final Object self, final Object constructor) {

        if (self instanceof PrototypeObject) {

            ((PrototypeObject)self).setConstructor(constructor);

        }

    }

    private Object getConstructor() {

        return constructor;

    }

    private void setConstructor(final Object constructor) {

        this.constructor = constructor;

    }

    private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) {

        return MH.findStatic(MethodHandles.lookup(), PrototypeObject.class, name, MH.type(rtype, types));

    }

}