paacompressor.js

var sys = require("sys");
var async = require('async');
var child_process = require('child_process');
var fs = require('fs');
var path = require('path');

var walk = function(dir, done) {
  var results = [];
  fs.readdir(dir, function(err, list) {
    if (err) return done(err);
    var pending = list.length;
    if (!pending) return done(null, results);
    list.forEach(function(file) {
      file = dir + '/' + file;
      fs.stat(file, function(err, stat) {
        if (stat && stat.isDirectory()) {
          walk(file, function(err, res) {
            results = results.concat(res);
            if (!--pending) done(null, results);
          });
        } else {
          results.push(file);
          if (!--pending) done(null, results);
        }
      });
    });
  });
};

var args = process.argv.slice(2);
var targetFolder = args[0];

var queue = [];
var MAX = 20; 
var count = 0;

function pngOpti_callback() {
	count -= 1;

	if (queue.length > 0 && count < MAX) {  // get next item in the queue
    	count += 1;

    	var file = queue.shift();
    	
    	child_process.spawn('Pal2PacE.exe', [file, file.replace('.paa', '.png')]).on('close', function () {

			console.log('Converted ' + file + ' to png...');

				child_process.spawn('optipng.exe', ['-o5', file.replace('.paa', '.png')]).on('close', function( ) {

					child_process.spawn('Pal2PacE.exe', [file.replace('.paa', '.png'), file]).on('close', function() {

						console.log('Optimized ' + file + '...');

						fs.unlink(file.replace('.paa', '.png'));

						pngOpti_callback();

					});

				});

		});
  	}
}

walk(targetFolder, function (err, files) {
	if (err) throw err;

	var paaFiles = files.filter(function (file) {
		return fs.statSync(file).isFile() && file.indexOf(".paa") != -1;
	}).sort(function(a, b) {
		return fs.statSync(a).size - fs.statSync(b).size;
	}).reverse();

	async.forEach(paaFiles, function (file, callback) {

		if (count < MAX) {

			count += 1;

			child_process.spawn('Pal2PacE.exe', [file, file.replace('.paa', '.png')]).on('close', function () {

				console.log('Converted ' + file + ' to png...');

					child_process.spawn('optipng.exe', ['-o5', file.replace('.paa', '.png')]).on('close', function( ) {

						child_process.spawn('Pal2PacE.exe', [file.replace('.paa', '.png'), file]).on('close', function() {

							console.log('Optimized ' + file + '...');

							fs.unlink(file.replace('.paa', '.png'));

							pngOpti_callback();

						});;

					});

			});

		} else { // queue up if we have maxed out our process limit
			queue.push(file);
		}

	});
});