1 files changed, 28 insertions, 1 deletions
diff --git a/app/helpers/diff_helper.rb b/app/helpers/diff_helper.rb
index 97466d532f4..9f73edb4553 100644
--- a/app/helpers/diff_helper.rb
+++ b/app/helpers/diff_helper.rb
@@ -23,7 +23,7 @@ module DiffHelper
   end
 
   def diff_options
-    options = { ignore_whitespace_change: params[:w] == '1' }
+    options = { ignore_whitespace_change: hide_whitespace? }
     if diff_hard_limit_enabled?
       options.merge!(Commit.max_diff_options)
     end
@@ -128,4 +128,31 @@ module DiffHelper
       title
     end
   end
+
+  def commit_diff_whitespace_link(project, commit, options)
+    url = namespace_project_commit_path(project.namespace, project, commit.id, params_with_whitespace)
+    toggle_whitespace_link(url, options)
+  end
+
+  def diff_merge_request_whitespace_link(project, merge_request, options)
+    url = diffs_namespace_project_merge_request_path(project.namespace, project, merge_request, params_with_whitespace)
+    toggle_whitespace_link(url, options)
+  end
+
+  private
+
+  def hide_whitespace?
+    params[:w] == '1'
+  end
+
+  def params_with_whitespace
+    hide_whitespace? ? request.query_parameters.except(:w) : request.query_parameters.merge(w: 1)
+  end
+
+  def toggle_whitespace_link(url, options)
+    options[:class] ||= ''
+    options[:class] << ' btn btn-default'
+
+    link_to "#{hide_whitespace? ? 'Show' : 'Hide'} whitespace changes", url, class: options[:class]
+  end
 end