source: Dev/trunk/src/client/util/build/optimizeRunner.js

/*jshint rhino:true white:false */
/*global Packages:false com:false */
function writeFile(filename, contents, encoding, cb) {
        if (arguments.length === 3 && typeof encoding !== "string") {
                cb = encoding;
                encoding = 0;
        }
        var
                outFile = new java.io.File(filename),
                outWriter;
        if(encoding){
                outWriter = new java.io.OutputStreamWriter(new java.io.FileOutputStream(outFile), encoding);
        }else{
                outWriter = new java.io.OutputStreamWriter(new java.io.FileOutputStream(outFile));
        }

        var os = new java.io.BufferedWriter(outWriter);
        try{
                os.write(contents);
        }finally{
                os.close();
        }
        if (cb) {
                cb(0);
        }
}

var built = "//>>built\n";

function sscompile(src, dest, optimizeSwitch, copyright){
        // decode the optimize switch
        var
                options = optimizeSwitch.split("."),
                comments = 0,
                keepLines = 0,
                strip = null;
        while(options.length){
                switch(options.pop()){
                        case "normal":
                                strip = "normal";
                                break;
                        case "warn":
                                strip = "warn";
                                break;
                        case "all":
                                strip = "all";
                                break;
                        case "keeplines":
                                keepLines = 1;
                                break;
                        case "comments":
                                comments = 1;
                                break;
                }
        }

        //Use rhino to help do minifying/compressing.
        var context = Packages.org.mozilla.javascript.Context.enter(),
                text;
        try{
                // Use the interpreter for interactive input (copied this from Main rhino class).
                context.setOptimizationLevel(-1);

                text = readFile(src, "utf-8");
                if(comments){
                        //Strip comments
                        var script = context.compileString(text, dest, 1, null);
                        text = new String(context.decompileScript(script, 0));

                        //Replace the spaces with tabs.
                        //Ideally do this in the pretty printer rhino code.
                        text = text.replace(/    /g, "\t");
                }else{
                        //Apply compression using custom compression call in Dojo-modified rhino.
                        text = new String(Packages.org.dojotoolkit.shrinksafe.Compressor.compressScript(text, 0, 1, strip));
                        if(!keepLines){
                                text = text.replace(/[\r\n]/g, "");
                        }
                }
        }finally{
                Packages.org.mozilla.javascript.Context.exit();
        }
        writeFile(dest, copyright + built + text, "utf-8");
}

var JSSourceFilefromCode, closurefromCode, jscomp = 0;
function ccompile(src, dest, optimizeSwitch, copyright, optimizeOptions, useSourceMaps){
        if(!jscomp){
                JSSourceFilefromCode=java.lang.Class.forName("com.google.javascript.jscomp.JSSourceFile").getMethod("fromCode", [java.lang.String, java.lang.String]);
                closurefromCode = function(filename,content){
                        return JSSourceFilefromCode.invoke(null,[filename,content]);
                };
                jscomp = com.google.javascript.jscomp;
        }

        //Fake extern
        var externSourceFile = closurefromCode("fakeextern.js", " ");

        //Set up source input
        // it is possible dest could have backslashes on windows (particularly with cygwin)
        var destFilename = dest.match(/^.+[\\\/](.+)$/)[1],
                jsSourceFile = closurefromCode(destFilename + ".uncompressed.js", String(readFile(src, "utf-8")));

        //Set up options
        var options = new jscomp.CompilerOptions();
        for(var k in optimizeOptions){
                options[k] = optimizeOptions[k];
        }
        // Must have non-null path to trigger source map generation, also fix version
        options.setSourceMapOutputPath("");
        options.setSourceMapFormat(jscomp.SourceMap.Format.V3);
        if(optimizeSwitch.indexOf(".keeplines") !== -1){
                options.prettyPrint = true;
        }

        var FLAG_compilation_level = jscomp.CompilationLevel.SIMPLE_OPTIMIZATIONS;
        FLAG_compilation_level.setOptionsForCompilationLevel(options);
        var FLAG_warning_level = jscomp.WarningLevel.DEFAULT;
        FLAG_warning_level.setOptionsForWarningLevel(options);

        //Prevent too-verbose logging output
        Packages.com.google.javascript.jscomp.Compiler.setLoggingLevel(java.util.logging.Level.SEVERE);

        // Run the compiler
        // File name and associated map name
        var mapTag = useSourceMaps ? ("\n//# sourceMappingURL=" + destFilename + ".map") : "",
                compiler = new Packages.com.google.javascript.jscomp.Compiler(Packages.java.lang.System.err);
        compiler.compile(externSourceFile, jsSourceFile, options);
        writeFile(dest, copyright + built + compiler.toSource() + mapTag, "utf-8");

        if(useSourceMaps){
                var sourceMap = compiler.getSourceMap();
                sourceMap.setWrapperPrefix(copyright + built);
                var sb = new java.lang.StringBuffer();
                sourceMap.appendTo(sb, destFilename);
                writeFile(dest + ".map", sb.toString(), "utf-8");
        }
}


var
        console = new java.io.BufferedReader(new java.io.InputStreamReader(java.lang.System["in"])),
        readLine = function(){
                // the + "" convert to a Javascript string
                return console.readLine() + "";
        },
        src,
        dest,
        optimizeSwitch;

while(1){
        src = readLine();
        if(src === "."){
                break;
        }
        dest = readLine();
        optimizeSwitch = readLine();
        var options = eval("(" + readLine() + ")");
        print(dest + ":");
        var start = (new Date()).getTime(),
                exception = "";
        try{
                if(/closure/.test(optimizeSwitch)){
                        ccompile(src, dest, optimizeSwitch, options.copyright, options.options, options.useSourceMaps);
                }else{
                        sscompile(src, dest, optimizeSwitch, options.copyright);
                }
        }catch(e){
                exception = ". OPTIMIZER FAILED: " + e;
        }
        print("Done (compile time:" + ((new Date()).getTime()-start)/1000 + "s)" + exception);
}