class Nokogiri::HTML5::Document

def self.do_parse(string_or_io, url, encoding, options)
  string = HTML5.read_and_encode(string_or_io, encoding)
  max_attributes = options[:max_attributes] || Nokogiri::Gumbo::DEFAULT_MAX_ATTRIBUTES
  max_errors = options[:max_errors] || options[:max_parse_errors] || Nokogiri::Gumbo::DEFAULT_MAX_ERRORS
  max_depth = options[:max_tree_depth] || Nokogiri::Gumbo::DEFAULT_MAX_TREE_DEPTH
  doc = Nokogiri::Gumbo.parse(string, url, max_attributes, max_errors, max_depth)
  doc.encoding = "UTF-8"
  doc
end

def self.parse(string_or_io, url = nil, encoding = nil, **options, &block)
  yield options if block
  string_or_io = "" unless string_or_io
  if string_or_io.respond_to?(:encoding) && string_or_io.encoding.name != "ASCII-8BIT"
    encoding ||= string_or_io.encoding.name
  end
  if string_or_io.respond_to?(:read) && string_or_io.respond_to?(:path)
    url ||= string_or_io.path
  end
  unless string_or_io.respond_to?(:read) || string_or_io.respond_to?(:to_str)
    raise ArgumentError, "not a string or IO object"
  end
  do_parse(string_or_io, url, encoding, options)
end

def self.read_io(io, url = nil, encoding = nil, **options)
  raise ArgumentError, "io object doesn't respond to :read" unless io.respond_to?(:read)
  do_parse(io, url, encoding, options)
end

def self.read_memory(string, url = nil, encoding = nil, **options)
  raise ArgumentError, "string object doesn't respond to :to_str" unless string.respond_to?(:to_str)
  do_parse(string, url, encoding, options)
end

def fragment(tags = nil)
  DocumentFragment.new(self, tags, root)
end

def to_xml(options = {}, &block)
  # Bypass XML::Document#to_xml which doesn't add
  # XML::Node::SaveOptions::AS_XML like XML::Node#to_xml does.
  XML::Node.instance_method(:to_xml).bind(self).call(options, &block)
end

def xpath_doctype
  Nokogiri::CSS::XPathVisitor::DoctypeConfig::HTML5
end