Move inline diff marker logic to its own class

lib/gitlab/diff/highlight.rb

@@ -12,32 +12,24 @@ module Gitlab
       end
 
       def highlight
-        return [] if @diff_lines.empty?
-
-        find_inline_diffs
-
-        process_lines
-
-        @diff_lines
-      end
-
-      private
-
-      def find_inline_diffs
-        @inline_diffs = InlineDiff.new(@raw_lines).inline_diffs
-      end
-
-      def process_lines
         @diff_lines.each_with_index do |diff_line, i|
           # ignore highlighting for "match" lines
           next if diff_line.type == 'match'
 
           rich_line = highlight_line(diff_line, i)
-          rich_line = mark_inline_diffs(rich_line, diff_line, i)
+
+          if line_inline_diffs = inline_diffs[i]
+            rich_line = InlineDiffMarker.new(diff_line.text, rich_line).mark(line_inline_diffs)
+          end
+
           diff_line.text = rich_line.html_safe
         end
+
+        @diff_lines
       end
 
+      private
+
       def highlight_line(diff_line, index)
         line_prefix = diff_line.text.match(/\A([+-])/) ? $1 : ' '
 
@@ -53,50 +45,8 @@ module Gitlab
         rich_line ? line_prefix + rich_line : diff_line.text
       end
 
-      def mark_inline_diffs(rich_line, diff_line, index)
-        line_inline_diffs = @inline_diffs[index]
-        return rich_line unless line_inline_diffs
-
-        raw_line = diff_line.text
-        position_mapping = map_character_positions(raw_line, rich_line)
-
-        offset = 0
-        line_inline_diffs.each do |inline_diff_range|
-          inline_diff_positions = position_mapping[inline_diff_range]
-          marker_ranges = collapse_ranges(inline_diff_positions)
-
-          marker_ranges.each do |range|
-            offset = insert_around_range(rich_line, range, "<span class='idiff'>", "</span>", offset)
-          end
-        end
-
-        rich_line
-      end
-
-      def map_character_positions(raw_line, rich_line)
-        mapping = []
-        raw_pos = 0
-        rich_pos = 0
-        (0..raw_line.length).each do |raw_pos|
-          raw_char = raw_line[raw_pos]
-          rich_char = rich_line[rich_pos]
-
-          while rich_char == '<'
-            until rich_char == '>'
-              rich_pos += 1
-              rich_char = rich_line[rich_pos]
-            end
-
-            rich_pos += 1
-            rich_char = rich_line[rich_pos]
-          end
-
-          mapping[raw_pos] = rich_pos
-
-          rich_pos += 1
-        end
-
-        mapping
+      def inline_diffs
+        @inline_diffs ||= InlineDiff.new(@raw_lines).inline_diffs
       end
 
       def old_lines
@@ -107,40 +57,6 @@ module Gitlab
         @new_lines ||= Gitlab::Highlight.highlight_lines(*processing_args(:new))
       end
 
-      def collapse_ranges(positions)
-        return [] if positions.empty?
-        ranges = []
-
-        start = prev = positions[0]
-        range = start..prev
-        positions[1..-1].each do |pos|
-          if pos == prev + 1
-            range = start..pos
-            prev = pos
-          else
-            ranges << range
-            start = prev = pos
-            range = start..prev
-          end
-        end
-        ranges << range
-
-        ranges
-      end
-
-      def insert_around_range(text, range, before, after, offset = 0)
-        from = range.begin
-        to = range.end
-
-        text.insert(offset + from, before)
-        offset += before.length
-
-        text.insert(offset + to + 1, after)
-        offset += after.length
-
-        offset
-      end
-
       def processing_args(version)
         ref  = send("diff_#{version}_ref")
         path = send("diff_#{version}_path")