class Sanitize

def to_html(node)
  replace_meta = false
  # Hacky workaround for a libxml2 bug that adds an undesired Content-Type
  # meta tag to all serialized HTML documents.
  #
  # https://github.com/sparklemotion/nokogiri/issues/1008
  if node.type == Nokogiri::XML::Node::DOCUMENT_NODE ||
      node.type == Nokogiri::XML::Node::HTML_DOCUMENT_NODE
    regex_meta   = %r|(<html[^>]*>\s*<head[^>]*>\s*)<meta http-equiv="Content-Type" content="text/html; charset=utf-8">|i
    # Only replace the content-type meta tag if <meta> isn't whitelisted or
    # the original document didn't actually include a content-type meta tag.
    replace_meta = !@config[:elements].include?('meta') ||
      node.xpath('/html/head/meta[@http-equiv]').none? do |meta|
        meta['http-equiv'].casecmp('content-type').zero?
      end
  end
  so = Nokogiri::XML::Node::SaveOptions
  # Serialize to HTML without any formatting to prevent Nokogiri from adding
  # newlines after certain tags.
  html = node.to_html(
    :encoding  => 'utf-8',
    :indent    => 0,
    :save_with => so::NO_DECLARATION | so::NO_EMPTY_TAGS | so::AS_HTML
  )
  html.gsub!(regex_meta, '\1') if replace_meta
  html
end