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_ELEMENT, 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.



216
217
218
 
# File 'lib/kramdown/parser/html.rb', line 216

def initialize(root)
  @root = root
end

Class Method Details

.convert(root, el = root) ⇒ Object 



220
221
222
 
# File 'lib/kramdown/parser/html.rb', line 220

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

Instance Method Details

#convert_a(el) ⇒ Object 



384
385
386
387
388
389
390
391
 
# File 'lib/kramdown/parser/html.rb', line 384

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 



417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
 
# File 'lib/kramdown/parser/html.rb', line 417

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
        mem << if [60, 62, 34, 38].include?(c.value.code_point)
                 c.value.code_point.chr
               else
                 c.value.char
               end
      elsif c.type == :smart_quote || c.type == :typographic_sym
        mem << entity(c.value.to_s).char
      else
        raise "Bug - please report"
      end
    end
    result.clear
    result << Element.new(:text, str)
  rescue StandardError
  end
  if result.length > 1 || result.first.type != :text
    process_html_element(el, false, true)
  else
    if el.value == 'code'
      set_basics(el, :codespan)
      el.attr['class']&.gsub!(/\s+\bhighlighter-\w+\b|\bhighlighter-\w+\b\s*/, '')
    else
      set_basics(el, :codeblock)
      if el.children.size == 1 && el.children.first.value == 'code'
        value = (el.children.first.attr['class'] || '').scan(/\blanguage-\S+/).first
        el.attr['class'] = "#{value} #{el.attr['class']}".rstrip if value
      end
    end
    el.value = result.first.value
    el.children.clear
  end
end

#convert_em(el) ⇒ Object 



394
395
396
397
398
399
400
401
402
403
 
# File 'lib/kramdown/parser/html.rb', line 394

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 



408
409
410
411
412
 
# File 'lib/kramdown/parser/html.rb', line 408

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 



563
564
565
566
567
568
569
 
# File 'lib/kramdown/parser/html.rb', line 563

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

#convert_table(el) ⇒ Object 



460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
 
# File 'lib/kramdown/parser/html.rb', line 460

def convert_table(el)
  unless 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 ? $1.to_sym : :default
        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

#convert_textarea(el) ⇒ Object 



380
381
382
 
# File 'lib/kramdown/parser/html.rb', line 380

def convert_textarea(el)
  process_html_element(el, true, true)
end

#extract_text(el, raw) ⇒ Object 



375
376
377
378
 
# File 'lib/kramdown/parser/html.rb', line 375

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 



575
576
577
578
579
 
# File 'lib/kramdown/parser/html.rb', line 575

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(?:%\s*)?<!\[CDATA\[\n?(.*?)(?:\s%)?\]\]>\z/m, '\1')
  el.attr.delete('type')
end

#is_math_tag?(el) ⇒ Boolean

Returns:

  • (Boolean) 


571
572
573
 
# File 'lib/kramdown/parser/html.rb', line 571

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

#is_simple_table?(el) ⇒ Boolean

Returns:

  • (Boolean) 


503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
 
# File 'lib/kramdown/parser/html.rb', line 503

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 do |c|
    if c.value == 'th' || c.value == 'td'
      return false unless 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 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.



225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
 
# File 'lib/kramdown/parser/html.rb', line 225

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.map! do |c|
      if c.type == :text
        process_text(c.value, !do_conversion)
      else
        process(c)
        c
      end
    end.flatten!
    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 



278
279
280
281
282
283
284
285
286
287
 
# File 'lib/kramdown/parser/html.rb', line 278

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 



320
321
322
323
324
 
# File 'lib/kramdown/parser/html.rb', line 320

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.



291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
 
# File 'lib/kramdown/parser/html.rb', line 291

def process_text(raw, preserve = false)
  raw.gsub!(/\s+/, ' ') unless preserve
  src = Kramdown::Utils::StringScanner.new(raw)
  result = []
  until src.eos?
    if (tmp = src.scan_until(/(?=#{HTML_ENTITY_RE})/o))
      result << Element.new(:text, tmp)
      src.scan(HTML_ENTITY_RE)
      val = src[1] || (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 



326
327
328
 
# File 'lib/kramdown/parser/html.rb', line 326

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

#remove_whitespace_children(el) ⇒ Object 



359
360
361
362
363
364
365
366
367
 
# File 'lib/kramdown/parser/html.rb', line 359

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 || ((el.children[i - 1]).block? &&
                                                 (el.children[i + 1]).block?))
  end
end

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



369
370
371
372
373
 
# File 'lib/kramdown/parser/html.rb', line 369

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

#strip_whitespace(el) ⇒ Object 



349
350
351
352
353
354
355
356
357
 
# File 'lib/kramdown/parser/html.rb', line 349

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 



330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
 
# File 'lib/kramdown/parser/html.rb', line 330

def wrap_text_children(el)
  tmp = []
  last_is_p = false
  el.children.each do |c|
    if !c.block? || c.type == :text
      unless 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