Module: PrettyDiff::WordDiffFinder

Extended by:
WordDiffFinder
Included in:
WordDiffFinder
Defined in:
lib/pretty_diff/word_diff_finder.rb

Constant Summary collapse

WDIFF_INSERTED_START = 
"\x01"
WDIFF_INSERTED_END = 
"\x02"
WDIFF_DELETED_START = 
"\x03"
WDIFF_DELETED_END = 
"\x04"

Instance Method Summary collapse

Instance Method Details

#find_word_diffs(lines) ⇒ Object 



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# File 'lib/pretty_diff/word_diff_finder.rb', line 13

def find_word_diffs(lines)
  dmp = DiffMatchPatch.new
  result = []
  added_next_line_already = false

  lines.each_with_index do |line, idx|
    if added_next_line_already
      added_next_line_already = false
      next
    end

    previous_line = idx > 0 ? lines[idx - 1] : nil
    stripped_line = strip(line)
    next_line = lines[idx + 1]
    stripped_next_line = strip(next_line || '')
    after_next_line = idx < lines.size ? lines[idx + 2] : nil

    # only show word diffing when change was a single line
    if changed_line?(line, next_line) && !changed_block?(previous_line, line, next_line, after_next_line) && similiar_lines?(stripped_line, stripped_next_line)
      diffs = dmp.diff_cleanup_semantic!(dmp.diff_main(stripped_line, stripped_next_line, true))
      replacement, next_replacement = join_diffs(diffs)

      if line.include?(replacement.first)
        # String#gsub in the form gsub(exp,replacement) has odd quirks
        # affecting the replacement string which sometimes require
        # lots of escaping slashes. Ruby users are frequently directed
        # to use the block form instead.
        # See: http://stackoverflow.com/a/13818467/204927
        line.gsub!(replacement.first) { replacement.last }
      else # it has to come form next_line
        next_line.gsub!(replacement.first) { replacement.last }
        added_next_line_already = true
      end

      if next_line && next_replacement
        next_line.gsub!(next_replacement.first) { next_replacement.last }
        added_next_line_already = true
      end
    end

    result << line

    if added_next_line_already
      result << next_line
    end
  end

  result
end