1 files changed, 50 insertions, 0 deletions
diff --git a/app/serializers/paginated_diff_entity.rb b/app/serializers/paginated_diff_entity.rb
new file mode 100644
index 00000000000..622da926c69
--- /dev/null
+++ b/app/serializers/paginated_diff_entity.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+# Serializes diffs with pagination data.
+#
+# Avoid adding more keys to this serializer as processing the
+# diff file serialization is not cheap.
+#
+class PaginatedDiffEntity < Grape::Entity
+  include RequestAwareEntity
+
+  expose :diff_files do |diffs, options|
+    submodule_links = Gitlab::SubmoduleLinks.new(merge_request.project.repository)
+    DiffFileEntity.represent(diffs.diff_files, options.merge(submodule_links: submodule_links))
+  end
+
+  expose :pagination do
+    expose :current_page
+    expose :next_page
+    expose :total_pages
+    expose :next_page_href do |diffs|
+      next unless next_page
+
+      project = merge_request.target_project
+
+      diffs_batch_namespace_project_json_merge_request_path(
+        namespace_id: project.namespace.to_param,
+        project_id: project.to_param,
+        id: merge_request.iid,
+        page: next_page,
+        format: :json
+      )
+    end
+  end
+
+  private
+
+  %i[current_page next_page total_pages].each do |method|
+    define_method method do
+      pagination_data[method]
+    end
+  end
+
+  def pagination_data
+    options.fetch(:pagination_data, {})
+  end
+
+  def merge_request
+    options[:merge_request]
+  end
+end