Class: Specdiff::Differ::Text

Inherits:
Object
  • Object
show all
Extended by:
Colorize
Defined in:
lib/specdiff/differ/text.rb

Constant Summary collapse

NEWLINE = 
"\n".freeze
CONTEXT_LINES = 
3

Class Method Summary collapse

Methods included from Colorize

blue, colorize_by_line, cyan, green, red, reset_color, yellow

Class Method Details

.diff(a, b) ⇒ Object

this implementation is based on RSpec::Support::Differ github.com/rspec/rspec-support/blob/main/lib/rspec/support/differ.rb and also the hunk generator it uses



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# File 'lib/specdiff/differ/text.rb', line 13

def self.diff(a, b)
  a_value = a.value
  b_value = b.value

  if a_value.encoding != b_value.encoding
    return colorize_by_line(<<~MSG) do |line|
      Strings have different encodings:
        #{a.value.encoding.inspect} != #{b.value.encoding.inspect}
    MSG
      # makes it stand out a bit more from the red of rspec output
      reset_color(line)
    end
  end

  diff = ""

  # if there are no newlines then the text differ doesn't produce any valuable
  # output. "word diffing" would improve this case.
  if a_value.count(NEWLINE) <= 1 && b_value.count(NEWLINE) <= 1
    return diff
  end

  a_lines = a_value.split(NEWLINE).map! { _1.chomp }
  b_lines = b_value.split(NEWLINE).map! { _1.chomp }

  file_length_difference = 0

  hunks = ::Diff::LCS.diff(a_lines, b_lines).map do |piece|
    ::Diff::LCS::Hunk.new(
      a_lines, b_lines, piece, CONTEXT_LINES, file_length_difference,
    ).tap { |hunk| file_length_difference = hunk.file_length_difference }
  end

  hunks.each_cons(2) do |prev_hunk, current_hunk|
    begin
      if current_hunk.overlaps?(prev_hunk)
        current_hunk.merge(prev_hunk)
      else
        diff << prev_hunk.diff(:unified)
      end
    ensure
      diff << NEWLINE
    end
  end

  if hunks.last
    diff << NEWLINE
    diff << hunks.last.diff(:unified)
  end

  return diff if diff == ""

  diff << NEWLINE
  diff.lstrip!

  return colorize_by_line(diff) do |line|
    case line[0].chr
    when "+"
      green(line)
    when "-"
      red(line)
    when "@"
      if line[1].chr == "@"
        cyan(line)
      else
        reset_color(line)
      end
    else
      reset_color(line)
    end
  end
end

.empty?(diff) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/specdiff/differ/text.rb', line 86

def self.empty?(diff)
  diff.raw == ""
end

.stringify(diff) ⇒ Object 



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# File 'lib/specdiff/differ/text.rb', line 90

def self.stringify(diff)
  diff.raw
end