Apply syntax highlighting when expanding diff plus some refactor. #3945

app/controllers/projects/blob_controller.rb

@@ -66,7 +66,7 @@ class Projects::BlobController < Projects::ApplicationController
 
   def diff
     @form = UnfoldForm.new(params)
-    @lines = @blob.data.lines[@form.since - 1..@form.to - 1]
+    @lines = Gitlab::Diff::Highlight.process_diff_lines(@blob.name, @blob.data.lines[@form.since - 1..@form.to - 1])
 
     if @form.bottom?
       @match_line = ''

app/views/projects/blob/diff.html.haml

@@ -11,7 +11,7 @@
       %td.old_line.diff-line-num{data: {linenumber: line_old}}
         = link_to raw(line_old), "#"
       %td.new_line= link_to raw(line_new) , "#"
-      %td.line_content.noteable_line= ' ' * @form.indent + line
+      %td.line_content.noteable_line= raw("#{' ' * @form.indent}#{line}")
 
   - if @form.unfold? && @form.bottom? && @form.to < @blob.loc
     %tr.line_holder{ id: @form.to }

lib/gitlab/diff/highlight.rb

 module Gitlab
   module Diff
     class Highlight
-      def self.process_diff_lines(file_name, diff_lines)
-        processor = new(file_name, diff_lines)
+      # Apply syntax highlight to provided source code
+      #
+      # file_name - The file name related to the code.
+      # lines     - It can be an Array of Gitlab::Diff::Line objects or simple Strings.
+      #             When passing Strings you need to provide the required 'end of lines'
+      #             chars ("\n") for each String given that we don't append them automatically.
+      #
+      # Returns an Array with the processed items.
+      def self.process_diff_lines(file_name, lines)
+        processor = new(file_name, lines)
         processor.highlight
       end
 
-      def initialize(file_name, diff_lines)
-        text_lines          = diff_lines.map(&:text)
+      def initialize(file_name, lines)
         @file_name  = file_name
-        @diff_lines         = diff_lines
-        @diff_line_prefixes = text_lines.map { |line| line.sub!(/\A((\+|\-)\s*)/, '');$1 }
-        @raw_lines          = text_lines.join("\n")
+        @lines      = lines
       end
 
       def highlight
-        @code = unescape_html(@raw_lines)
+        return [] if @lines.empty?
+
+        extract_line_prefixes
+
+        @code             = unescape_html(raw_content)
         @highlighted_code = formatter.format(lexer.lex(@code))
 
-        update_diff_lines
+        is_diff_line? ? update_diff_lines : @highlighted_code.lines
       end
 
       private
 
+      def is_diff_line?
+        @lines.first.is_a?(Gitlab::Diff::Line)
+      end
+
+      def text_lines
+        @text_lines ||= (is_diff_line? ? @lines.map(&:text) : @lines)
+      end
+
+      def raw_content
+        @raw_content ||= text_lines.join(is_diff_line? ? "\n" : nil)
+      end
+
+      def extract_line_prefixes
+        @diff_line_prefixes ||= begin
+          if is_diff_line?
+            text_lines.map { |line| line.sub!(/\A((\+|\-)\s*)/, '');$1 }
+          else
+            []
+          end
+        end
+      end
+
       def update_diff_lines
         @highlighted_code.lines.each_with_index do |line, i|
-          diff_line = @diff_lines[i]
+          diff_line = @lines[i]
 
           # ignore highlighting for "match" lines
           next if diff_line.type == 'match'
@@ -33,7 +64,7 @@ module Gitlab
           diff_line.text = "#{@diff_line_prefixes[i]}#{line}"
         end
 
-        @diff_lines
+        @lines
       end
 
       def lexer

spec/lib/gitlab/diff/highlight_spec.rb

@@ -9,6 +9,7 @@ describe Gitlab::Diff::Highlight, lib: true do
   let(:diff_file) { Gitlab::Diff::File.new(diff) }
 
   describe '.process_diff_lines' do
+    context 'when processing Gitlab::Diff::Line objects' do
       let(:diff_lines) { Gitlab::Diff::Highlight.process_diff_lines(diff_file.new_path, diff_file.diff_lines) }
 
       it 'should return Gitlab::Diff::Line elements' do
@@ -30,4 +31,19 @@ describe Gitlab::Diff::Highlight, lib: true do
         expect(diff_lines[22].text).to eq('@@ -19,6 +25,7 @@ module Popen')
       end
     end
+
+    context 'when processing raw lines' do
+      let(:lines) { ["puts 'Hello'\n", "# A comment"] }
+      let(:highlighted_lines) { Gitlab::Diff::Highlight.process_diff_lines('demo.rb', lines) }
+
+      it 'should highlight the code' do
+        line_1 = %Q{<span id="LC1" class="line"><span class="nb">puts</span> <span class="s1">&#39;Hello&#39;</span></span>\n}
+        line_2 = %Q{<span id="LC2" class="line"><span class="c1"># A comment</span></span>}
+
+        expect(highlighted_lines[0]).to eq(line_1)
+        expect(highlighted_lines[1]).to eq(line_2)
+      end
+    end
+
+  end
 end