/*

 * 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

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package com.sun.script.javascript;

import sun.org.mozilla.javascript.internal.*;

import javax.script.*;

/**

 * This class serves as top level scope for Rhino. This class adds

 * 3 top level functions (bindings, scope, sync) and two constructors

 * (JSAdapter, JavaAdapter).

 *

 * @author A. Sundararajan

 * @since 1.6

 */

public final class RhinoTopLevel extends ImporterTopLevel {

    RhinoTopLevel(Context cx, RhinoScriptEngine engine) {

        super(cx);

        this.engine = engine;

        // initialize JSAdapter lazily. Reduces footprint & startup time.

        new LazilyLoadedCtor(this, "JSAdapter",

                "com.sun.script.javascript.JSAdapter",

                false);

        /*

         * initialize JavaAdapter. We can't lazy initialize this because

         * lazy initializer attempts to define a new property. But, JavaAdapter

         * is an exisiting property that we overwrite.

         */

        JavaAdapter.init(cx, this, false);

        // add top level functions

        String names[] = { "bindings", "scope", "sync"  };

        defineFunctionProperties(names, RhinoTopLevel.class,

                ScriptableObject.DONTENUM);

    }

    /**

     * The bindings function takes a JavaScript scope object

     * of type ExternalScriptable and returns the underlying Bindings

     * instance.

     *

     *    var page = scope(pageBindings);

     *    with (page) {

     *       // code that uses page scope

     *    }

     *    var b = bindings(page);

     *    // operate on bindings here.

     */

    public static Object bindings(Context cx, Scriptable thisObj, Object[] args,

            Function funObj) {

        if (args.length == 1) {

            Object arg = args[0];

            if (arg instanceof Wrapper) {

                arg = ((Wrapper)arg).unwrap();

            }

            if (arg instanceof ExternalScriptable) {

                ScriptContext ctx = ((ExternalScriptable)arg).getContext();

                Bindings bind = ctx.getBindings(ScriptContext.ENGINE_SCOPE);

                return Context.javaToJS(bind,

                           ScriptableObject.getTopLevelScope(thisObj));

            }

        }

        return cx.getUndefinedValue();

    }

    /**

     * The scope function creates a new JavaScript scope object

     * with given Bindings object as backing store. This can be used

     * to create a script scope based on arbitrary Bindings instance.

     * For example, in webapp scenario, a 'page' level Bindings instance

     * may be wrapped as a scope and code can be run in JavaScripe 'with'

     * statement:

     *

     *    var page = scope(pageBindings);

     *    with (page) {

     *       // code that uses page scope

     *    }

     */

    public static Object scope(Context cx, Scriptable thisObj, Object[] args,

            Function funObj) {

        if (args.length == 1) {

            Object arg = args[0];

            if (arg instanceof Wrapper) {

                arg = ((Wrapper)arg).unwrap();

            }

            if (arg instanceof Bindings) {

                ScriptContext ctx = new SimpleScriptContext();

                ctx.setBindings((Bindings)arg, ScriptContext.ENGINE_SCOPE);

                Scriptable res = new ExternalScriptable(ctx);

                res.setPrototype(ScriptableObject.getObjectPrototype(thisObj));

                res.setParentScope(ScriptableObject.getTopLevelScope(thisObj));

                return res;

            }

        }

        return cx.getUndefinedValue();

    }

    /**

     * The sync function creates a synchronized function (in the sense

     * of a Java synchronized method) from an existing function. The

     * new function synchronizes on the <code>this</code> object of

     * its invocation.

     * js> var o = { f : sync(function(x) {

     *       print("entry");

     *       Packages.java.lang.Thread.sleep(x*1000);

     *       print("exit");

     *     })};

     * js> thread(function() {o.f(5);});

     * entry

     * js> thread(function() {o.f(5);});

     * js>

     * exit

     * entry

     * exit

     */

    public static Object sync(Context cx, Scriptable thisObj, Object[] args,

            Function funObj) {

        if (args.length == 1 && args[0] instanceof Function) {

            return new Synchronizer((Function)args[0]);

        } else {

            throw Context.reportRuntimeError("wrong argument(s) for sync");

        }

    }

    RhinoScriptEngine getScriptEngine() {

        return engine;

    }

    private RhinoScriptEngine engine;

}