gitlab-org--gitlab-foss/lib/gitlab/diff/char_diff.rb

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# frozen_string_literal: true
module Gitlab
module Diff
class CharDiff
include Gitlab::Utils::StrongMemoize
def initialize(old_string, new_string)
@old_string = old_string.to_s
@new_string = new_string.to_s
@changes = []
end
def generate_diff
@changes = diff_match_patch.diff_main(@old_string, @new_string)
diff_match_patch.diff_cleanupSemantic(@changes)
@changes
end
def changed_ranges(offset: 0)
old_diffs = []
new_diffs = []
new_pointer = old_pointer = offset
generate_diff.each do |(action, content)|
content_size = content.size
if action == :equal
new_pointer += content_size
old_pointer += content_size
end
if action == :delete
old_diffs << MarkerRange.new(old_pointer, old_pointer + content_size - 1, mode: MarkerRange::DELETION)
old_pointer += content_size
end
if action == :insert
new_diffs << MarkerRange.new(new_pointer, new_pointer + content_size - 1, mode: MarkerRange::ADDITION)
new_pointer += content_size
end
end
[old_diffs, new_diffs]
end
def to_html
@changes.map do |op, text|
%{<span class="#{html_class_names(op)}">#{ERB::Util.html_escape(text)}</span>}
end.join.html_safe
end
private
def diff_match_patch
strong_memoize(:diff_match_patch) { DiffMatchPatch.new }
end
def html_class_names(operation)
class_names = ['idiff']
case operation
when :insert
class_names << 'addition'
when :delete
class_names << 'deletion'
end
class_names.join(' ')
end
end
end
end