public static String checkFileName()

in commons-fileupload2-core/src/main/java/org/apache/commons/fileupload2/core/DiskFileItem.java [145:168]

• 22 lines of code
• 5 McCabe index (conditional complexity)

    public static String checkFileName(final String fileName) {
        if (fileName != null) {
            // Specific NUL check to build a better exception message.
            final var indexOf0 = fileName.indexOf(0);
            if (indexOf0 != -1) {
                final var sb = new StringBuilder();
                for (var i = 0; i < fileName.length(); i++) {
                    final var c = fileName.charAt(i);
                    switch (c) {
                    case 0:
                        sb.append("\\0");
                        break;
                    default:
                        sb.append(c);
                        break;
                    }
                }
                throw new InvalidPathException(fileName, sb.toString(), indexOf0);
            }
            // Throws InvalidPathException on invalid file names
            Paths.get(fileName);
        }
        return fileName;
    }