public static String getUrlForLibraryRoot(@NotNull File libraryRoot) {
   String path = FileUtil.toSystemIndependentName(libraryRoot.getAbsolutePath());
   if (FileTypeManager.getInstance().getFileTypeByFileName(libraryRoot.getName())
       == FileTypes.ARCHIVE) {
     return VirtualFileManager.constructUrl(
         JarFileSystem.getInstance().getProtocol(), path + JarFileSystem.JAR_SEPARATOR);
   } else {
     return VirtualFileManager.constructUrl(LocalFileSystem.getInstance().getProtocol(), path);
   }
 }
  @SuppressWarnings({"HardCodedStringLiteral"})
  @Nullable
  public static VirtualFile findRelativeFile(@NotNull String uri, @Nullable VirtualFile base) {
    if (base != null) {
      if (!base.isValid()) {
        LOG.error("Invalid file name: " + base.getName() + ", url: " + uri);
      }
    }

    uri = uri.replace('\\', '/');

    if (uri.startsWith("file:///")) {
      uri = uri.substring("file:///".length());
      if (!SystemInfo.isWindows) uri = "/" + uri;
    } else if (uri.startsWith("file:/")) {
      uri = uri.substring("file:/".length());
      if (!SystemInfo.isWindows) uri = "/" + uri;
    } else if (uri.startsWith("file:")) {
      uri = uri.substring("file:".length());
    }

    VirtualFile file = null;

    if (uri.startsWith("jar:file:/")) {
      uri = uri.substring("jar:file:/".length());
      if (!SystemInfo.isWindows) uri = "/" + uri;
      file = VirtualFileManager.getInstance().findFileByUrl(JarFileSystem.PROTOCOL_PREFIX + uri);
    } else {
      if (!SystemInfo.isWindows && StringUtil.startsWithChar(uri, '/')) {
        file = LocalFileSystem.getInstance().findFileByPath(uri);
      } else if (SystemInfo.isWindows
          && uri.length() >= 2
          && Character.isLetter(uri.charAt(0))
          && uri.charAt(1) == ':') {
        file = LocalFileSystem.getInstance().findFileByPath(uri);
      }
    }

    if (file == null && uri.contains(JarFileSystem.JAR_SEPARATOR)) {
      file = JarFileSystem.getInstance().findFileByPath(uri);
      if (file == null && base == null) {
        file = VirtualFileManager.getInstance().findFileByUrl(uri);
      }
    }

    if (file == null) {
      if (base == null) return LocalFileSystem.getInstance().findFileByPath(uri);
      if (!base.isDirectory()) base = base.getParent();
      if (base == null) return LocalFileSystem.getInstance().findFileByPath(uri);
      file = VirtualFileManager.getInstance().findFileByUrl(base.getUrl() + "/" + uri);
      if (file == null) return null;
    }

    return file;
  }