Class: DiscourseDiff

Inherits:
Object
  • Object
show all
Defined in:
lib/discourse_diff.rb

Defined Under Namespace

Classes: HtmlTokenizer

Constant Summary collapse

MAX_DIFFERENCE = 
200

Instance Method Summary collapse

Constructor Details

#initialize(before, after) ⇒ DiscourseDiff

Returns a new instance of DiscourseDiff.



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# File 'lib/discourse_diff.rb', line 6

def initialize(before, after)
  @before = before
  @after = after
  before_html = tokenize_html_blocks(@before)
  after_html = tokenize_html_blocks(@after)
  before_markdown = tokenize_line(CGI.escapeHTML(@before))
  after_markdown = tokenize_line(CGI.escapeHTML(@after))

  @block_by_block_diff = ONPDiff.new(before_html, after_html).paragraph_diff
  @line_by_line_diff = ONPDiff.new(before_markdown, after_markdown).short_diff
end

Instance Method Details

#inline_html ⇒ Object 



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# File 'lib/discourse_diff.rb', line 18

def inline_html
  i = 0
  inline = []
  while i < @block_by_block_diff.size
    op_code = @block_by_block_diff[i][1]
    if op_code == :common
      inline << @block_by_block_diff[i][0]
    else
      if op_code == :delete
        opposite_op_code = :add
        klass = "del"
        first = i
        second = i + 1
      else
        opposite_op_code = :delete
        klass = "ins"
        first = i + 1
        second = i
      end

      if i + 1 < @block_by_block_diff.size && @block_by_block_diff[i + 1][1] == opposite_op_code
        diff =
          ONPDiff.new(
            tokenize_html(@block_by_block_diff[first][0]),
            tokenize_html(@block_by_block_diff[second][0]),
          ).diff
        inline << generate_inline_html(diff)
        i += 1
      else
        inline << add_class_or_wrap_in_tags(@block_by_block_diff[i][0], klass)
      end
    end
    i += 1
  end

  "<div class=\"inline-diff\">#{inline.join}</div>"
end

#side_by_side_html ⇒ Object 



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# File 'lib/discourse_diff.rb', line 56

def side_by_side_html
  i = 0
  left, right = [], []
  while i < @block_by_block_diff.size
    op_code = @block_by_block_diff[i][1]
    if op_code == :common
      left << @block_by_block_diff[i][0]
      right << @block_by_block_diff[i][0]
    else
      if op_code == :delete
        opposite_op_code = :add
        side = left
        klass = "del"
        first = i
        second = i + 1
      else
        opposite_op_code = :delete
        side = right
        klass = "ins"
        first = i + 1
        second = i
      end

      if i + 1 < @block_by_block_diff.size && @block_by_block_diff[i + 1][1] == opposite_op_code
        diff =
          ONPDiff.new(
            tokenize_html(@block_by_block_diff[first][0]),
            tokenize_html(@block_by_block_diff[second][0]),
          ).diff
        deleted, inserted = generate_side_by_side_html(diff)
        left << deleted
        right << inserted
        i += 1
      else
        side << add_class_or_wrap_in_tags(@block_by_block_diff[i][0], klass)
      end
    end
    i += 1
  end

  "<div class=\"revision-content\">#{left.join}</div><div class=\"revision-content\">#{right.join}</div>"
end

#side_by_side_markdown ⇒ Object 



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# File 'lib/discourse_diff.rb', line 99

def side_by_side_markdown
  i = 0
  table = ["<table class=\"markdown\">"]
  while i < @line_by_line_diff.size
    table << "<tr>"
    op_code = @line_by_line_diff[i][1]
    if op_code == :common
      table << "<td>#{@line_by_line_diff[i][0]}</td>"
      table << "<td>#{@line_by_line_diff[i][0]}</td>"
    else
      if op_code == :delete
        opposite_op_code = :add
        first = i
        second = i + 1
      else
        opposite_op_code = :delete
        first = i + 1
        second = i
      end

      if i + 1 < @line_by_line_diff.size && @line_by_line_diff[i + 1][1] == opposite_op_code
        before_tokens, after_tokens =
          tokenize_markdown(@line_by_line_diff[first][0]),
          tokenize_markdown(@line_by_line_diff[second][0])
        if (before_tokens.size - after_tokens.size).abs > MAX_DIFFERENCE
          before_tokens, after_tokens =
            tokenize_line(@line_by_line_diff[first][0]),
            tokenize_line(@line_by_line_diff[second][0])
        end
        diff = ONPDiff.new(before_tokens, after_tokens).short_diff
        deleted, inserted = generate_side_by_side_markdown(diff)
        table << "<td class=\"diff-del\">#{deleted.join}</td>"
        table << "<td class=\"diff-ins\">#{inserted.join}</td>"
        i += 1
      else
        if op_code == :delete
          table << "<td class=\"diff-del\">#{@line_by_line_diff[i][0]}</td>"
          table << "<td></td>"
        else
          table << "<td></td>"
          table << "<td class=\"diff-ins\">#{@line_by_line_diff[i][0]}</td>"
        end
      end
    end
    table << "</tr>"
    i += 1
  end
  table << "</table>"

  table.join
end