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.

16 files changed, 64 insertions, 56 deletions

diff --git a/app/controllers/admin/application_settings_controller.rb b/app/controllers/admin/application_settings_controller.rb
index 8040a14ef56..8f683ca06ad 100644
--- a/app/controllers/admin/application_settings_controller.rb
+++ b/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
diff --git a/app/controllers/projects/blob_controller.rb b/app/controllers/projects/blob_controller.rb
index 56a884b8a2a..c02ec407262 100644
--- a/app/controllers/projects/blob_controller.rb
+++ b/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)
 
diff --git a/app/helpers/blob_helper.rb b/app/helpers/blob_helper.rb
index ff7f1e3a9aa..52cf9d12287 100644
--- a/app/helpers/blob_helper.rb
+++ b/app/helpers/blob_helper.rb
@@ -1,9 +1,9 @@
 # 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
diff --git a/app/views/projects/blob/viewers/_highlight_embed.html.haml b/app/views/projects/blob/viewers/_highlight_embed.html.haml
index 9bd4ef6ad0b..6a631fef1a9 100644
--- a/app/views/projects/blob/viewers/_highlight_embed.html.haml
+++ b/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
diff --git a/app/views/projects/blob/viewers/_text.html.haml b/app/views/projects/blob/viewers/_text.html.haml
index a91df321ca0..26ad23da436 100644
--- a/app/views/projects/blob/viewers/_text.html.haml
+++ b/app/views/projects/blob/viewers/_text.html.haml
@@ -1 +1 @@
-= render 'shared/file_highlight', blob: viewer.blob, repository: @repository
+= render 'shared/file_highlight', blob: viewer.blob
diff --git a/app/views/projects/settings/ci_cd/_badge.html.haml b/app/views/projects/settings/ci_cd/_badge.html.haml
index d14360913a4..82c8ec088e5 100644
--- a/app/views/projects/settings/ci_cd/_badge.html.haml
+++ b/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
diff --git a/app/views/search/results/_snippet_blob.html.haml b/app/views/search/results/_snippet_blob.html.haml
index 8b95bdf9747..92ea6f281f4 100644
--- a/app/views/search/results/_snippet_blob.html.haml
+++ b/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
diff --git a/app/views/shared/_file_highlight.html.haml b/app/views/shared/_file_highlight.html.haml
index 8d64cb5d698..5073e6ad48f 100644
--- a/app/views/shared/_file_highlight.html.haml
+++ b/app/views/shared/_file_highlight.html.haml
@@ -1,5 +1,3 @@
-- 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
diff --git a/app/views/sherlock/queries/_general.html.haml b/app/views/sherlock/queries/_general.html.haml
index ddc089b0bd7..52c7bc47ca7 100644
--- a/app/views/sherlock/queries/_general.html.haml
+++ b/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
diff --git a/app/views/sherlock/transactions/_queries.html.haml b/app/views/sherlock/transactions/_queries.html.haml
index c1ec4b91bb6..5e224f3aa0e 100644
--- a/app/views/sherlock/transactions/_queries.html.haml
+++ b/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),
diff --git a/lib/gitlab/blame.rb b/lib/gitlab/blame.rb
index 0d79594363e..f1a653a9d95 100644
--- a/lib/gitlab/blame.rb
+++ b/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
diff --git a/lib/gitlab/conflict/file.rb b/lib/gitlab/conflict/file.rb
index 30911b49b18..501c2111530 100644
--- a/lib/gitlab/conflict/file.rb
+++ b/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
diff --git a/lib/gitlab/diff/highlight.rb b/lib/gitlab/diff/highlight.rb
index a605ddb5c33..1d833183ec3 100644
--- a/lib/gitlab/diff/highlight.rb
+++ b/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
diff --git a/lib/gitlab/highlight.rb b/lib/gitlab/highlight.rb
index 83095acc528..d28223194cc 100644
--- a/lib/gitlab/highlight.rb
+++ b/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
 
-      return nil unless language_name
-
-      Rouge::Lexer.find_fancy(language_name)
+      Rouge::Lexer.find_fancy(@language)
     end
 
     def highlight_text(text, continue: true, plain: false)
diff --git a/spec/lib/gitlab/highlight_spec.rb b/spec/lib/gitlab/highlight_spec.rb
index 88f7099ff3c..77179260a66 100644
--- a/spec/lib/gitlab/highlight_spec.rb
+++ b/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
diff --git a/spec/views/projects/blob/_viewer.html.haml_spec.rb b/spec/views/projects/blob/_viewer.html.haml_spec.rb
index aedbaa66d34..95f7f87d37b 100644
--- a/spec/views/projects/blob/_viewer.html.haml_spec.rb
+++ b/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