Class: Kramdown::Parser::Html::ElementConverter

Inherits:
Object
  • Object
show all
Includes:
Constants, Utils::Entities
Defined in:
lib/kramdown/parser/html.rb

Overview

Converts HTML elements to native elements if possible.

Constant Summary collapse

REMOVE_TEXT_CHILDREN = 
%w{html head hgroup ol ul dl table colgroup tbody thead tfoot tr select optgroup}
WRAP_TEXT_CHILDREN = 
%w{body section nav article aside header footer address div li dd blockquote figure
figcaption fieldset form}
REMOVE_WHITESPACE_CHILDREN = 
%w{body section nav article aside header footer address
div li dd blockquote figure figcaption td th fieldset form}
STRIP_WHITESPACE = 
%w{address article aside blockquote body caption dd div dl dt fieldset figcaption form footer
header h1 h2 h3 h4 h5 h6 legend li nav p section td th}
SIMPLE_ELEMENTS = 
%w{em strong blockquote hr br img p thead tbody tfoot tr td th ul ol dl li dl dt dd}
EMPHASIS_TYPE_MAP = 
{'em' => :em, 'i' => :em, 'strong' => :strong, 'b' => :strong}

Constants included from Utils::Entities

Utils::Entities::ENTITY_MAP, Utils::Entities::ENTITY_TABLE

Constants included from Constants

Constants::HTML_ATTRIBUTE_RE, Constants::HTML_BLOCK_ELEMENTS, Constants::HTML_COMMENT_RE, Constants::HTML_CONTENT_MODEL, Constants::HTML_CONTENT_MODEL_BLOCK, Constants::HTML_CONTENT_MODEL_RAW, Constants::HTML_CONTENT_MODEL_SPAN, Constants::HTML_DOCTYPE_RE, Constants::HTML_ELEMENTS_WITHOUT_BODY, Constants::HTML_ENTITY_RE, Constants::HTML_INSTRUCTION_RE, Constants::HTML_SPAN_ELEMENTS, Constants::HTML_TAG_CLOSE_RE, Constants::HTML_TAG_RE

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Utils::Entities

entity

Constructor Details

#initialize(root) ⇒ ElementConverter

Returns a new instance of ElementConverter.



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# File 'lib/kramdown/parser/html.rb', line 187

def initialize(root)
  @root = root
end

Class Method Details

.convert(root, el = root) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 191

def self.convert(root, el = root)
  new(root).process(el)
end

Instance Method Details

#convert_a(el) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 344

def convert_a(el)
  if el.attr['href']
    set_basics(el, :a)
    process_children(el)
  else
    process_html_element(el, false)
  end
end

#convert_code(el) ⇒ Object Also known as: convert_pre 



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# File 'lib/kramdown/parser/html.rb', line 377

def convert_code(el)
  raw = ''
  extract_text(el, raw)
  result = process_text(raw, true)
  begin
    str = result.inject('') do |mem, c|
      if c.type == :text
        mem << c.value
      elsif c.type == :entity
        if RUBY_VERSION >= '1.9'
          mem << c.value.char.encode(@root.options[:encoding])
        elsif [60, 62, 34, 38].include?(c.value.code_point)
          mem << c.value.code_point.chr
        end
      elsif c.type == :smart_quote || c.type == :typographic_sym
        mem << entity(c.value.to_s).char.encode(@root.options[:encoding])
      else
        raise "Bug - please report"
      end
    end
    result.clear
    result << Element.new(:text, str)
  rescue
  end
  if result.length > 1 || result.first.type != :text
    process_html_element(el, false, true)
  else
    if el.value == 'code'
      set_basics(el, :codespan)
    else
      set_basics(el, :codeblock)
    end
    el.value = result.first.value
    el.children.clear
  end
end

#convert_em(el) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 354

def convert_em(el)
  text = ''
  extract_text(el, text)
  if text =~ /\A\s/ || text =~ /\s\z/
    process_html_element(el, false)
  else
    set_basics(el, EMPHASIS_TYPE_MAP[el.value])
    process_children(el)
  end
end

#convert_h1(el) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 368

def convert_h1(el)
  set_basics(el, :header, :level => el.value[1..1].to_i)
  extract_text(el, el.options[:raw_text] = '')
  process_children(el)
end

#convert_script(el) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 518

def convert_script(el)
  if !is_math_tag?(el)
    process_html_element(el)
  else
    handle_math_tag(el)
  end
end

#convert_table(el) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 415

def convert_table(el)
  if !is_simple_table?(el)
    process_html_element(el, false)
    return
  end
  remove_text_children(el)
  process_children(el)
  set_basics(el, :table)

  calc_alignment = lambda do |c|
    if c.type == :tr
      el.options[:alignment] = c.children.map do |td|
        if td.attr['style']
          td.attr['style'].slice!(/(?:;\s*)?text-align:\s+(center|left|right)/)
          td.attr.delete('style') if td.attr['style'].strip.empty?
          $1.to_sym
        else
          :default
        end
      end
    else
      c.children.each {|cc| calc_alignment.call(cc)}
    end
  end
  calc_alignment.call(el)
  el.children.delete_if {|c| c.type == :html_element}

  change_th_type = lambda do |c|
    if c.type == :th
      c.type = :td
    else
      c.children.each {|cc| change_th_type.call(cc)}
    end
  end
  change_th_type.call(el)

  if el.children.first.type == :tr
    tbody = Element.new(:tbody)
    tbody.children = el.children
    el.children = [tbody]
  end
end

#extract_text(el, raw) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 339

def extract_text(el, raw)
  raw << el.value.to_s if el.type == :text
  el.children.each {|c| extract_text(c, raw)}
end

#handle_math_tag(el) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 530

def handle_math_tag(el)
  set_basics(el, :math, :category => (el.attr['type'] =~ /mode=display/ ? :block : :span))
  el.value = el.children.shift.value.sub(/\A<!\[CDATA\[(.*)\]\]>\z/m, '\1')
  el.attr.delete('type')
end

#is_math_tag?(el) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/kramdown/parser/html.rb', line 526

def is_math_tag?(el)
  el.attr['type'].to_s =~ /\bmath\/tex\b/
end

#is_simple_table?(el) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/kramdown/parser/html.rb', line 458

def is_simple_table?(el)
  only_phrasing_content = lambda do |c|
    c.children.all? do |cc|
      (cc.type == :text || !HTML_BLOCK_ELEMENTS.include?(cc.value)) && only_phrasing_content.call(cc)
    end
  end
  check_cells = Proc.new do |c|
    if c.value == 'th' || c.value == 'td'
      return false if !only_phrasing_content.call(c)
    else
      c.children.each {|cc| check_cells.call(cc)}
    end
  end
  check_cells.call(el)

  nr_cells = 0
  check_nr_cells = lambda do |t|
    if t.value == 'tr'
      count = t.children.select {|cc| cc.value == 'th' || cc.value == 'td'}.length
      if count != nr_cells
        if nr_cells == 0
          nr_cells = count
        else
          nr_cells = -1
          break
        end
      end
    else
      t.children.each {|cc| check_nr_cells.call(cc)}
    end
  end
  check_nr_cells.call(el)
  return false if nr_cells == -1

  alignment = nil
  check_alignment = Proc.new do |t|
    if t.value == 'tr'
      cur_alignment = t.children.select {|cc| cc.value == 'th' || cc.value == 'td'}.map do |cell|
        md = /text-align:\s+(center|left|right|justify|inherit)/.match(cell.attr['style'].to_s)
        return false if md && (md[1] == 'justify' || md[1] == 'inherit')
        md.nil? ? :default : md[1]
      end
      alignment = cur_alignment if alignment.nil?
      return false if alignment != cur_alignment
    else
      t.children.each {|cc| check_alignment.call(cc)}
    end
  end
  check_alignment.call(el)

  check_rows = lambda do |t, type|
    t.children.all? {|r| (r.value == 'tr' || r.type == :text) && r.children.all? {|c| c.value == type || c.type == :text}}
  end
  check_rows.call(el, 'td') ||
    (el.children.all? do |t|
       t.type == :text || (t.value == 'thead' && check_rows.call(t, 'th')) ||
         ((t.value == 'tfoot' || t.value == 'tbody') && check_rows.call(t, 'td'))
     end && el.children.any? {|t| t.value == 'tbody'})
end

#process(el, do_conversion = true, preserve_text = false, parent = nil) ⇒ Object

Convert the element el and its children.



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# File 'lib/kramdown/parser/html.rb', line 196

def process(el, do_conversion = true, preserve_text = false, parent = nil)
  case el.type
  when :xml_comment, :xml_pi
    ptype = if parent.nil?
              'div'
            else
              case parent.type
              when :html_element then parent.value
              when :code_span then 'code'
              when :code_block then 'pre'
              when :header then 'h1'
              else parent.type.to_s
              end
            end
    el.options.replace({:category => (HTML_CONTENT_MODEL[ptype] == :span ? :span : :block)})
    return
  when :html_element
  when :root
    el.children.each {|c| process(c)}
    remove_whitespace_children(el)
    return
  else return
  end

  mname = "convert_#{el.value}"
  if do_conversion && self.class.method_defined?(mname)
    send(mname, el)
  else
    type = el.value
    remove_text_children(el) if do_conversion && REMOVE_TEXT_CHILDREN.include?(type)

    if do_conversion && SIMPLE_ELEMENTS.include?(type)
      set_basics(el, type.intern)
      process_children(el, do_conversion, preserve_text)
    else
      process_html_element(el, do_conversion, preserve_text)
    end

    if do_conversion
      strip_whitespace(el) if STRIP_WHITESPACE.include?(type)
      remove_whitespace_children(el) if REMOVE_WHITESPACE_CHILDREN.include?(type)
      wrap_text_children(el) if WRAP_TEXT_CHILDREN.include?(type)
    end
  end
end

#process_children(el, do_conversion = true, preserve_text = false) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 242

def process_children(el, do_conversion = true, preserve_text = false)
  el.children.map! do |c|
    if c.type == :text
      process_text(c.value, preserve_text || !do_conversion)
    else
      process(c, do_conversion, preserve_text, el)
      c
    end
  end.flatten!
end

#process_html_element(el, do_conversion = true, preserve_text = false) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 284

def process_html_element(el, do_conversion = true, preserve_text = false)
  el.options.replace(:category => HTML_SPAN_ELEMENTS.include?(el.value) ? :span : :block,
                     :content_model => (do_conversion ? HTML_CONTENT_MODEL[el.value] : :raw))
  process_children(el, do_conversion, preserve_text)
end

#process_text(raw, preserve = false) ⇒ Object

Process the HTML text raw: compress whitespace (if preserve is false) and convert entities in entity elements.



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# File 'lib/kramdown/parser/html.rb', line 255

def process_text(raw, preserve = false)
  raw.gsub!(/\s+/, ' ') unless preserve
  src = StringScanner.new(raw)
  result = []
  while !src.eos?
    if tmp = src.scan_until(/(?=#{HTML_ENTITY_RE})/)
      result << Element.new(:text, tmp)
      src.scan(HTML_ENTITY_RE)
      val = src[1] || (src[2] && src[2].to_i) || src[3].hex
      result << if %w{lsquo rsquo ldquo rdquo}.include?(val)
                  Element.new(:smart_quote, val.intern)
                elsif %w{mdash ndash hellip laquo raquo}.include?(val)
                  Element.new(:typographic_sym, val.intern)
                else
                  begin
                    Element.new(:entity, entity(val), nil, :original => src.matched)
                  rescue ::Kramdown::Error
                    src.pos -= src.matched_size - 1
                    Element.new(:entity, ::Kramdown::Utils::Entities.entity('amp'))
                  end
                end
    else
      result << Element.new(:text, src.rest)
      src.terminate
    end
  end
  result
end

#remove_text_children(el) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 290

def remove_text_children(el)
  el.children.delete_if {|c| c.type == :text}
end

#remove_whitespace_children(el) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 323

def remove_whitespace_children(el)
  i = -1
  el.children = el.children.reject do |c|
    i += 1
    c.type == :text && c.value.strip.empty? &&
      (i == 0 || i == el.children.length - 1 || (Element.category(el.children[i-1]) == :block &&
                                                 Element.category(el.children[i+1]) == :block))
  end
end

#set_basics(el, type, opts = {}) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 333

def set_basics(el, type, opts = {})
  el.type = type
  el.options.replace(opts)
  el.value = nil
end

#strip_whitespace(el) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 313

def strip_whitespace(el)
  return if el.children.empty?
  if el.children.first.type == :text
    el.children.first.value.lstrip!
  end
  if el.children.last.type == :text
    el.children.last.value.rstrip!
  end
end

#wrap_text_children(el) ⇒ Object 



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# File 'lib/kramdown/parser/html.rb', line 294

def wrap_text_children(el)
  tmp = []
  last_is_p = false
  el.children.each do |c|
    if Element.category(c) != :block || c.type == :text
      if !last_is_p
        tmp << Element.new(:p, nil, nil, :transparent => true)
        last_is_p = true
      end
      tmp.last.children << c
      tmp
    else
      tmp << c
      last_is_p = false
    end
  end
  el.children = tmp
end