Make Highlight accept language param

This replaces the repository param.
This allows more flexiblity as sometimes we have highlight content
not related to repository. Sometimes we know ahead of time the language
of the content. Lastly language determination seems better fit as a
logic in the Blob class.
`repository` param is only used to determine the language, which seems
to be the responsiblity of Blob.

app/controllers/admin/application_settings_controller.rb

@@ -61,7 +61,7 @@ class Admin::ApplicationSettingsController < Admin::ApplicationController
       format.html do
         usage_data_json = JSON.pretty_generate(Gitlab::UsageData.data)
-        render html: Gitlab::Highlight.highlight('payload.json', usage_data_json)
+        render html: Gitlab::Highlight.highlight('payload.json', usage_data_json, language: 'json')
       end
       format.json { render json: Gitlab::UsageData.to_json }
     end

app/controllers/projects/blob_controller.rb

@@ -92,7 +92,7 @@ class Projects::BlobController < Projects::ApplicationController
     apply_diff_view_cookie!
     @blob.load_all_data!
-    @lines = Gitlab::Highlight.highlight(@blob.path, @blob.data, repository: @repository).lines
+    @lines = @blob.present.highlight.lines
     @form = UnfoldForm.new(params)

app/helpers/blob_helper.rb

 # frozen_string_literal: true
 module BlobHelper
-  def highlight(blob_name, blob_content, repository: nil, plain: false)
-    plain ||= blob_content.length > Blob::MAXIMUM_TEXT_HIGHLIGHT_SIZE
-    highlighted = Gitlab::Highlight.highlight(blob_name, blob_content, plain: plain, repository: repository)
+  def highlight(file_name, file_content, language: nil, plain: false)
+    plain ||= file_content.length > Blob::MAXIMUM_TEXT_HIGHLIGHT_SIZE
+    highlighted = Gitlab::Highlight.highlight(file_name, file_content, plain: plain, language: language)
     raw %(<pre class="code highlight"><code>#{highlighted}</code></pre>)
   end

app/views/projects/blob/viewers/_highlight_embed.html.haml

@@ -4,4 +4,6 @@
       - blob.data.each_line.each_with_index do |_, index|
         %span.diff-line-num= index + 1
   .blob-content{ data: { blob_id: blob.id } }
-    = highlight(blob.path, blob.data, repository: nil, plain: blob.no_highlighting?)
+    %pre.code.highlight
+      %code
+        = blob.present.highlight

app/views/projects/blob/viewers/_text.html.haml

-= render 'shared/file_highlight', blob: viewer.blob, repository: @repository
+= render 'shared/file_highlight', blob: viewer.blob

app/views/projects/settings/ci_cd/_badge.html.haml

@@ -15,14 +15,14 @@
           .col-md-2.text-center
             Markdown
           .col-md-10.code.js-syntax-highlight
-            = highlight('.md', badge.to_markdown)
+            = highlight('.md', badge.to_markdown, language: 'markdown')
         .row
           %hr
         .row
           .col-md-2.text-center
             HTML
           .col-md-10.code.js-syntax-highlight
-            = highlight('.html', badge.to_html)
+            = highlight('.html', badge.to_html, language: 'html')
         .row
           %hr
         .row

app/views/search/results/_snippet_blob.html.haml

@@ -39,7 +39,7 @@
         .blob-content
           - snippet_chunks.each do |chunk|
             - unless chunk[:data].empty?
-              = highlight(snippet.file_name, chunk[:data], repository: nil, plain: snippet.blob.no_highlighting?)
+              = highlight(snippet.file_name, chunk[:data], plain: snippet.blob.no_highlighting?)
             - else
               .file-content.code
                 .nothing-here-block Empty file

app/views/shared/_file_highlight.html.haml

-- repository = nil unless local_assigns.key?(:repository)
-
 .file-content.code.js-syntax-highlight
   .line-numbers
     - if blob.data.present?
@@ -13,4 +11,6 @@
           = link_icon
           = i
   .blob-content{ data: { blob_id: blob.id } }
-    = highlight(blob.path, blob.data, repository: repository, plain: blob.no_highlighting?)
+    %pre.code.highlight
+      %code
+        = blob.present.highlight

app/views/sherlock/queries/_general.html.haml

@@ -36,7 +36,7 @@
       %li
         .code.js-syntax-highlight.sherlock-code
           :preserve
-            #{highlight("#{@query.id}.sql", @query.formatted_query)}
+            #{highlight("#{@query.id}.sql", @query.formatted_query, language: 'sql')}
   .card
     .card-header

app/views/sherlock/transactions/_queries.html.haml

@@ -17,7 +17,7 @@
               = t('sherlock.milliseconds')
             %td
               .code.js-syntax-highlight.sherlock-code
-                = highlight("#{query.id}.sql", query.formatted_query)
+                = highlight("#{query.id}.sql", query.formatted_query, language: 'sql')
             %td
               = link_to(t('sherlock.view'),
                 sherlock_transaction_query_path(@transaction, query),

lib/gitlab/blame.rb

@@ -43,8 +43,7 @@ module Gitlab
     def highlighted_lines
       @blob.load_all_data!
-      @highlighted_lines ||=
-        Gitlab::Highlight.highlight(@blob.path, @blob.data, repository: repository).lines
+      @highlighted_lines ||= @blob.present.highlight.lines
     end
     def project

lib/gitlab/conflict/file.rb

@@ -3,6 +3,7 @@ module Gitlab
     class File
       include Gitlab::Routing
       include IconsHelper
+      include Gitlab::Utils::StrongMemoize
       CONTEXT_LINES = 3
@@ -30,11 +31,8 @@ module Gitlab
       end
       def highlight_lines!
-        their_file = lines.reject { |line| line.type == 'new' }.map(&:text).join("\n")
-        our_file = lines.reject { |line| line.type == 'old' }.map(&:text).join("\n")
-
-        their_highlight = Gitlab::Highlight.highlight(their_path, their_file, repository: repository).lines
-        our_highlight = Gitlab::Highlight.highlight(our_path, our_file, repository: repository).lines
+        their_highlight = Gitlab::Highlight.highlight(their_path, their_lines, language: their_language).lines
+        our_highlight = Gitlab::Highlight.highlight(our_path, our_lines, language: our_language).lines
         lines.each do |line|
           line.rich_text =
@@ -182,6 +180,34 @@ module Gitlab
             raw_line[:line_new], parent_file: self)
         end
       end
+
+      def their_language
+        strong_memoize(:their_language) do
+          repository.gitattribute(their_path, 'gitlab-language')
+        end
+      end
+
+      def our_language
+        strong_memoize(:our_language) do
+          if our_path == their_path
+            their_language
+          else
+            repository.gitattribute(our_path, 'gitlab-language')
+          end
+        end
+      end
+
+      def their_lines
+        strong_memoize(:their_lines) do
+          lines.reject { |line| line.type == 'new' }.map(&:text).join("\n")
+        end
+      end
+
+      def our_lines
+        strong_memoize(:our_lines) do
+          lines.reject { |line| line.type == 'old' }.map(&:text).join("\n")
+        end
+      end
     end
   end
 end

lib/gitlab/diff/highlight.rb

@@ -79,7 +79,7 @@ module Gitlab
         return [] unless blob
         blob.load_all_data!
-        Gitlab::Highlight.highlight(blob.path, blob.data, repository: repository).lines
+        blob.present.highlight.lines
       end
     end
   end

lib/gitlab/highlight.rb

@@ -5,16 +5,16 @@ module Gitlab
     TIMEOUT_BACKGROUND = 30.seconds
     TIMEOUT_FOREGROUND = 3.seconds
-    def self.highlight(blob_name, blob_content, repository: nil, plain: false)
-      new(blob_name, blob_content, repository: repository)
+    def self.highlight(blob_name, blob_content, language: nil, plain: false)
+      new(blob_name, blob_content, language: language)
         .highlight(blob_content, continue: false, plain: plain)
     end
     attr_reader :blob_name
-    def initialize(blob_name, blob_content, repository: nil)
+    def initialize(blob_name, blob_content, language: nil)
       @formatter = Rouge::Formatters::HTMLGitlab
-      @repository = repository
+      @language = language
       @blob_name = blob_name
       @blob_content = blob_content
     end
@@ -36,11 +36,9 @@ module Gitlab
     private
     def custom_language
-      language_name = @repository && @repository.gitattribute(@blob_name, 'gitlab-language')
-      return nil unless language_name
-
-      Rouge::Lexer.find_fancy(language_name)
+      return nil unless @language
+      Rouge::Lexer.find_fancy(@language)
     end
     def highlight_text(text, continue: true, plain: false)

spec/lib/gitlab/highlight_spec.rb

@@ -5,34 +5,15 @@ describe Gitlab::Highlight do
   let(:project) { create(:project, :repository) }
   let(:repository) { project.repository }
-  let(:commit) { project.commit(sample_commit.id) }
-
-  describe 'custom highlighting from .gitattributes' do
-    let(:branch) { 'gitattributes' }
-    let(:blob) { repository.blob_at_branch(branch, path) }
+  describe 'language provided' do
     let(:highlighter) do
-      described_class.new(blob.path, blob.data, repository: repository)
-    end
-
-    before do
-      project.change_head('gitattributes')
-    end
-
-    describe 'basic language selection' do
-      let(:path) { 'custom-highlighting/test.gitlab-custom' }
-      it 'highlights as ruby' do
-        expect(highlighter.lexer.tag).to eq 'ruby'
-      end
+      described_class.new('foo.erb', 'bar', language: 'erb?parent=json')
     end
-    describe 'cgi options' do
-      let(:path) { 'custom-highlighting/test.gitlab-cgi' }
-
-      it 'highlights as json with erb' do
-        expect(highlighter.lexer.tag).to eq 'erb'
-        expect(highlighter.lexer.parent.tag).to eq 'json'
-      end
+    it 'sets correct lexer' do
+      expect(highlighter.lexer.tag).to eq 'erb'
+      expect(highlighter.lexer.parent.tag).to eq 'json'
     end
   end
@@ -42,7 +23,7 @@ describe Gitlab::Highlight do
       let(:path) { 'files/whitespace' }
       let(:blob) { repository.blob_at_branch(branch, path) }
       let(:lines) do
-        described_class.highlight(blob.path, blob.data, repository: repository).lines
+        described_class.highlight(blob.path, blob.data).lines
       end
       it 'strips extra LFs' do

spec/views/projects/blob/_viewer.html.haml_spec.rb

@@ -29,6 +29,8 @@ describe 'projects/blob/_viewer.html.haml' do
     controller.params[:namespace_id] = project.namespace.to_param
     controller.params[:project_id] = project.to_param
     controller.params[:id] = File.join('master', blob.path)
+
+    allow(project.repository).to receive(:gitattribute).and_return(nil)
   end
   def render_view