/**
   * Finds all files in folder and in it's sub-tree of specified depth.
   *
   * @param file Starting folder
   * @param maxDepth Depth of the tree. If 1 - just look in the folder, no sub-folders.
   * @param filter file filter.
   * @return List of found files.
   */
  public static List<VisorLogFile> fileTree(File file, int maxDepth, @Nullable FileFilter filter) {
    if (file.isDirectory()) {
      File[] files = (filter == null) ? file.listFiles() : file.listFiles(filter);

      if (files == null) return Collections.emptyList();

      List<VisorLogFile> res = new ArrayList<>(files.length);

      for (File f : files) {
        if (f.isFile() && f.length() > 0) res.add(new VisorLogFile(f));
        else if (maxDepth > 1) res.addAll(fileTree(f, maxDepth - 1, filter));
      }

      return res;
    }

    return F.asList(new VisorLogFile(file));
  }
  /**
   * Garbage collect repository
   *
   * @throws Exception
   */
  public void gc() throws Exception {
    HashSet<byte[]> deps = new HashSet<byte[]>();

    // deps.add(SERVICE_JAR_FILE);

    for (File cmd : commandDir.listFiles()) {
      CommandData data = getData(CommandData.class, cmd);
      addDependencies(deps, data);
    }

    for (File service : serviceDir.listFiles()) {
      File dataFile = new File(service, "data");
      ServiceData data = getData(ServiceData.class, dataFile);
      addDependencies(deps, data);
    }

    int count = 0;
    for (File f : repoDir.listFiles()) {
      String name = f.getName();
      if (!deps.contains(name)) {
        if (!name.endsWith(".json")
            || !deps.contains(name.substring(0, name.length() - ".json".length()))) { // Remove
          // json
          // files
          // only
          // if
          // the
          // bin
          // is
          // going
          // as
          // well
          f.delete();
          count++;
        } else {

        }
      }
    }
    System.out.format("Garbage collection done (%d file(s) removed)%n", count);
  }
 static Folder fromDirectory(File dir) throws IOException {
   List<Document> documents = new LinkedList<>();
   List<Folder> subFolders = new LinkedList<>();
   for (File entry : dir.listFiles()) {
     if (entry.isDirectory()) {
       subFolders.add(Folder.fromDirectory(entry));
     } else {
       documents.add(Document.fromFile(entry));
     }
   }
   return new Folder(subFolders, documents);
 }
  public List<CommandData> getCommands(File commandDir) throws Exception {
    List<CommandData> result = new ArrayList<CommandData>();

    if (!commandDir.exists()) {
      return result;
    }

    for (File f : commandDir.listFiles()) {
      CommandData data = getData(CommandData.class, f);
      if (data != null) result.add(data);
    }
    return result;
  }
  public List<ServiceData> getServices(File serviceDir) throws Exception {
    List<ServiceData> result = new ArrayList<ServiceData>();

    if (!serviceDir.exists()) {
      return result;
    }

    for (File sdir : serviceDir.listFiles()) {
      File dataFile = new File(sdir, "data");
      ServiceData data = getData(ServiceData.class, dataFile);
      result.add(data);
    }
    return result;
  }