text: const process = require("./process_pak");
  const fs = require("fs");
  const path = require("path");
  const Exception = require("./Exception");
  
  const set_default_root = function() {};
  const get_root = function() {
    if (process.get_arch() === "win32") {
      //windows
      return "c:\\";
    } else {
      //linux||os
      return "/";
    }
  };
  const is_abs = function() {};
  const ls = function(path, callback) {
    if (is_dir(path)) {
      fs.readdir(path, function(err, rs) {
        callback(err, rs);
      });
    } else {
      throw new Error("该路径不是目录!");
    }
  };
  const del = function(path) {};
  const mkdir = function(path, name) {};
  
  const is_dir = function(path) {
    return fs.statSync(path).isDirectory();
  };
  module.exports = {
    get_root,
    ls,
    is_dir
  };
  