free_mutant/lib/mutant/diff.rb
2014-06-29 22:56:08 +00:00

114 lines
2 KiB
Ruby

module Mutant
# Class to create diffs from source code
class Diff
include Adamantium::Flat, Concord.new(:old, :new)
ADDITION = '+'.freeze
DELETION = '-'.freeze
NEWLINE = "\n".freeze
# Return source diff
#
# @return [String]
# if there is exactly one diff
#
# @return [nil]
# otherwise
#
# @api private
#
def diff
return unless diffs.length.equal?(1)
::Diff::LCS::Hunk.new(old, new, diffs.first, max_length, 0)
.diff(:unified) << NEWLINE
end
memoize :diff
# Return colorized source diff
#
# @return [String]
# if there is a diff
#
# @return [nil]
# otherwise
#
# @api private
#
def colorized_diff
return unless diff
diff.lines.map do |line|
self.class.colorize_line(line)
end.join
end
memoize :colorized_diff
# Return new object
#
# @param [String] old
# @param [String] new
#
# @return [Diff]
#
# @api private
#
def self.build(old, new)
new(lines(old), lines(new))
end
# Break up source into lines
#
# @param [String] source
#
# @return [Array<String>]
#
# @api private
#
def self.lines(source)
source.lines.map { |line| line.chomp }
end
private_class_method :lines
private
# Return diffs
#
# @return [Array<Array>]
#
# @api private
#
def diffs
::Diff::LCS.diff(old, new)
end
memoize :diffs
# Return max length
#
# @return [Fixnum]
#
# @api private
#
def max_length
[old, new].map(&:length).max
end
# Return colorized diff line
#
# @param [String] line
#
# @return [String]
#
# @api private
#
def self.colorize_line(line)
case line[0]
when ADDITION
Color::GREEN
when DELETION
Color::RED
else
Color::NONE
end.format(line)
end
end # Diff
end # Mutant