proof of concept: highlight in chunks

3 files changed, 26 insertions, 7 deletions

diff --git a/app/helpers/blob_helper.rb b/app/helpers/blob_helper.rb
index abe115d8c68..16ddecf9c2d 100644
--- a/app/helpers/blob_helper.rb
+++ b/app/helpers/blob_helper.rb
@@ -1,7 +1,16 @@
 module BlobHelper
-  def highlight(blob_name, blob_content, repository: nil, plain: false)
-    highlighted = Gitlab::Highlight.highlight(blob_name, blob_content, plain: plain, repository: repository)
-    raw %(<pre class="code highlight"><code>#{highlighted}</code></pre>)
+  include Hamlit::HamlHelpers
+
+  def highlight(blob_name, blob_content, repository: nil, plain: false, &block)
+    unless block_given?
+      return raw enum_for(:highlight, blob_name, blob_content, repository: repository, plain: false).to_a.join
+    end
+
+    yield raw('<pre class="code highlight><code>')
+    Gitlab::Highlight.stream_highlight(blob_name, blob_content, plain: plain, repository: repository) do |chunk|
+      yield raw(chunk)
+    end
+    yield raw('</code></pre>')
   end
 
   def no_highlight_files
diff --git a/app/views/shared/_file_highlight.html.haml b/app/views/shared/_file_highlight.html.haml
index e26693bf5b9..231e912a2d4 100644
--- a/app/views/shared/_file_highlight.html.haml
+++ b/app/views/shared/_file_highlight.html.haml
@@ -12,5 +12,6 @@
         %a.diff-line-num{href: "#{link}#L#{i}", id: "L#{i}", 'data-line-number' => i}
           = link_icon
           = i
-  .blob-content{data: {blob_id: blob.id}}
-    = highlight(blob.path, blob.data, repository: repository, plain: blob.no_highlighting?)
+  .blob-content{data: {blob_id: blob.id}}><
+    - highlight(blob.path, blob.data, repository: repository, plain: blob.no_highlighting?) do |chunk|
+      ~ chunk
diff --git a/lib/gitlab/highlight.rb b/lib/gitlab/highlight.rb
index 9360afedfcb..c33b1513638 100644
--- a/lib/gitlab/highlight.rb
+++ b/lib/gitlab/highlight.rb
@@ -5,6 +5,11 @@ module Gitlab
         highlight(blob_content, continue: false, plain: plain)
     end
 
+    def self.stream_highlight(blob_name, blob_content, repository: nil, plain: false, &b)
+      new(blob_name, blob_content, repository: repository).
+        highlight(blob_content, continue: false, plain: plain, &b)
+    end
+
     def self.highlight_lines(repository, ref, file_name)
       blob = repository.blob_at(ref, file_name)
       return [] unless blob
@@ -20,7 +25,7 @@ module Gitlab
       @blob_content = blob_content
     end
 
-    def highlight(text, continue: true, plain: false)
+    def highlight(text, continue: true, plain: false, &b)
       if plain
         hl_lexer = Rouge::Lexers::PlainText
         continue = false
@@ -28,7 +33,11 @@ module Gitlab
         hl_lexer = self.lexer
       end
 
-      @formatter.format(hl_lexer.lex(text, continue: continue)).html_safe
+      if b
+        @formatter.format(hl_lexer.lex(text, continue: continue), &b)
+      else
+        @formatter.format(hl_lexer.lex(text, continue: continue)).html_safe
+      end
     rescue
       @formatter.format(Rouge::Lexers::PlainText.lex(text)).html_safe
     end