lib/nokogiri/html4/document.rb


# coding: utf-8
# frozen_string_literal: true

require "pathname"

module Nokogiri
  module HTML4
    class Document < Nokogiri::XML::Document
      ###
      # Get the meta tag encoding for this document.  If there is no meta tag,
      # then nil is returned.
      def meta_encoding
        if (meta = at_xpath("//meta[@charset]"))
          meta[:charset]
        elsif (meta = meta_content_type)
          meta["content"][/charset\s*=\s*([\w-]+)/i, 1]
        end
      end

      ###
      # Set the meta tag encoding for this document.
      #
      # If an meta encoding tag is already present, its content is
      # replaced with the given text.
      #
      # Otherwise, this method tries to create one at an appropriate
      # place supplying head and/or html elements as necessary, which
      # is inside a head element if any, and before any text node or
      # content element (typically <body>) if any.
      #
      # The result when trying to set an encoding that is different
      # from the document encoding is undefined.
      #
      # Beware in CRuby, that libxml2 automatically inserts a meta tag
      # into a head element.
      def meta_encoding=(encoding)
        if (meta = meta_content_type)
          meta["content"] = format("text/html; charset=%s", encoding)
          encoding
        elsif (meta = at_xpath("//meta[@charset]"))
          meta["charset"] = encoding
        else
          meta = XML::Node.new("meta", self)
          if (dtd = internal_subset) && dtd.html5_dtd?
            meta["charset"] = encoding
          else
            meta["http-equiv"] = "Content-Type"
            meta["content"] = format("text/html; charset=%s", encoding)
          end

          if (head = at_xpath("//head"))
            head.prepend_child(meta)
          else
            set_metadata_element(meta)
          end
          encoding
        end
      end

      def meta_content_type
        xpath("//meta[@http-equiv and boolean(@content)]").find do |node|
          node["http-equiv"] =~ /\AContent-Type\z/i
        end
      end
      private :meta_content_type

      ###
      # Get the title string of this document.  Return nil if there is
      # no title tag.
      def title
        (title = at_xpath("//title")) && title.inner_text
      end

      ###
      # Set the title string of this document.
      #
      # If a title element is already present, its content is replaced
      # with the given text.
      #
      # Otherwise, this method tries to create one at an appropriate
      # place supplying head and/or html elements as necessary, which
      # is inside a head element if any, right after a meta
      # encoding/charset tag if any, and before any text node or
      # content element (typically <body>) if any.
      def title=(text)
        tnode = XML::Text.new(text, self)
        if (title = at_xpath("//title"))
          title.children = tnode
          return text
        end

        title = XML::Node.new("title", self) << tnode
        if (head = at_xpath("//head"))
          head << title
        elsif (meta = at_xpath("//meta[@charset]") || meta_content_type)
          # better put after charset declaration
          meta.add_next_sibling(title)
        else
          set_metadata_element(title)
        end
      end

      def set_metadata_element(element) # rubocop:disable Naming/AccessorMethodName
        if (head = at_xpath("//head"))
          head << element
        elsif (html = at_xpath("//html"))
          head = html.prepend_child(XML::Node.new("head", self))
          head.prepend_child(element)
        elsif (first = children.find do |node|
                 case node
                 when XML::Element, XML::Text
                   true
                 end
               end)
          # We reach here only if the underlying document model
          # allows <html>/<head> elements to be omitted and does not
          # automatically supply them.
          first.add_previous_sibling(element)
        else
          html = add_child(XML::Node.new("html", self))
          head = html.add_child(XML::Node.new("head", self))
          head.prepend_child(element)
        end
      end
      private :set_metadata_element

      ####
      # Serialize Node using +options+. Save options can also be set using a block.
      #
      # See also Nokogiri::XML::Node::SaveOptions and Node@Serialization+and+Generating+Output.
      #
      # These two statements are equivalent:
      #
      #  node.serialize(:encoding => 'UTF-8', :save_with => FORMAT | AS_XML)
      #
      # or
      #
      #   node.serialize(:encoding => 'UTF-8') do |config|
      #     config.format.as_xml
      #   end
      #
      def serialize(options = {})
        options[:save_with] ||= XML::Node::SaveOptions::DEFAULT_HTML
        super
      end

      ####
      # Create a Nokogiri::XML::DocumentFragment from +tags+
      def fragment(tags = nil)
        DocumentFragment.new(self, tags, root)
      end

      # :call-seq:
      #   xpath_doctype() → Nokogiri::CSS::XPathVisitor::DoctypeConfig
      #
      # [Returns] The document type which determines CSS-to-XPath translation.
      #
      # See XPathVisitor for more information.
      def xpath_doctype
        Nokogiri::CSS::XPathVisitor::DoctypeConfig::HTML4
      end

      class << self
        # :call-seq:
        #   parse(input) { |options| ... } => Nokogiri::HTML4::Document
        #   parse(input, url:, encoding:, options:) => Nokogiri::HTML4::Document
        #
        # Parse \HTML4 input from a String or IO object, and return a new HTML4::Document.
        #
        # [Required Parameters]
        # - +input+ (String | IO) The content to be parsed.
        #
        # [Optional Keyword Arguments]
        # - +url:+ (String) The base URI for this document.
        #
        # - +encoding:+ (String) The name of the encoding that should be used when processing the
        #   document. When not provided, the encoding will be determined based on the document
        #   content.
        #
        # - +options:+ (Nokogiri::XML::ParseOptions) Configuration object that determines some
        #   behaviors during parsing. See ParseOptions for more information. The default value is
        #   +ParseOptions::DEFAULT_HTML+.
        #
        # [Yields]
        #   If a block is given, a Nokogiri::XML::ParseOptions object is yielded to the block which
        #   can be configured before parsing. See Nokogiri::XML::ParseOptions for more information.
        #
        # [Returns] Nokogiri::HTML4::Document
        def parse(
          input,
          url_ = nil, encoding_ = nil, options_ = XML::ParseOptions::DEFAULT_HTML,
          url: url_, encoding: encoding_, options: options_
        )
          options = Nokogiri::XML::ParseOptions.new(options) if Integer === options
          yield options if block_given?

          url ||= input.respond_to?(:path) ? input.path : nil

          if input.respond_to?(:encoding)
            unless input.encoding == Encoding::ASCII_8BIT
              encoding ||= input.encoding.name
            end
          end

          if input.respond_to?(:read)
            if input.is_a?(Pathname)
              # resolve the Pathname to the file and open it as an IO object, see #2110
              input = input.expand_path.open
              url ||= input.path
            end

            unless encoding
              input = EncodingReader.new(input)
              begin
                return read_io(input, url, encoding, options.to_i)
              rescue EncodingReader::EncodingFound => e
                encoding = e.found_encoding
              end
            end
            return read_io(input, url, encoding, options.to_i)
          end

          # read_memory pukes on empty docs
          if input.nil? || input.empty?
            return encoding ? new.tap { |i| i.encoding = encoding } : new
          end

          encoding ||= EncodingReader.detect_encoding(input)

          read_memory(input, url, encoding, options.to_i)
        end
      end
    end
  end
end