An early glimpse on rhino performance improvements i'm working on

benchmark.js

// an early glimpse on rhino performance improvements i'm working on. 
// this will require both the native-callsites and non-object-this branches 
// on http://github.com/hns/rhino-8 to be applicable to vanilla strings

>> defineClass(org.ringojs.wrappers.FastString)
>> var fast = new FastString("foo")
>> var str = "foo"
>> var timer = require("ringo/utils").timer
>> timer(function() {for (var i = 0; i < 10000000; i++) str.indexOf("f");})
7720 millis
>> timer(function() {for (var i = 0; i < 10000000; i++) fast.indexOf("f");})
928 millis
>> timer(function() {for (var i = 0; i < 10000000; i++) str.toUpperCase();})
8447 millis
>> timer(function() {for (var i = 0; i < 10000000; i++) fast.toUpperCase();})
1587 millis

FastString.java

package org.ringojs.wrappers;

import org.mozilla.javascript.Context;
import org.mozilla.javascript.Function;
import org.mozilla.javascript.Scriptable;
import org.mozilla.javascript.ScriptableObject;
import org.mozilla.javascript.annotations.JSFunction;
import org.mozilla.javascript.annotations.JSStaticFunction;

// Note: there's nothing special about this host class (except for the missing 
// input validation). I'm just including it for the sake of completeness. The 
// performance gains stem from the native-callsites branch at 
// <http://github.com/hns/rhino-8>, and the non-object-this branch should transfer
// that to string and number methods. 
// See <http://wiki.github.com/hns/rhino-8/> for more information.

public class FastString extends ScriptableObject {

    private String string;

    public FastString() {}

    public FastString(String string) {
        this.string = string;
    }

    public String getClassName() {
        return "FastString";
    }

    @JSFunction
    @JSStaticFunction
    public static Object indexOf(Context cx, Scriptable thisObj, 
                                 Object[] args, Function funObj) {
        String str, pattern;
        if (thisObj == null) {
            str = args[0].toString();
            pattern = args[1].toString();
        } else {
            str = thisObj.toString();
            pattern = args[0].toString();
        }
        return Integer.valueOf(str.indexOf(pattern));
    }

    @JSFunction
    public String toUpperCase() {
        return string.toUpperCase();
    }

    @Override
    @JSFunction
    public String toString() {
        return this.string;
    }

}