1 files changed, 35 insertions, 0 deletions
diff --git a/lib/gitlab/diff/file_collection/paginated_merge_request_diff.rb b/lib/gitlab/diff/file_collection/paginated_merge_request_diff.rb
new file mode 100644
index 00000000000..37abad81305
--- /dev/null
+++ b/lib/gitlab/diff/file_collection/paginated_merge_request_diff.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Diff
+    module FileCollection
+      # Builds a traditional paginated diff file collection using Kaminari
+      # `per` and `per_page` which is different from how `MergeRequestDiffBatch`
+      # works (e.g. supports gradual loading).
+      class PaginatedMergeRequestDiff < MergeRequestDiffBase
+        include PaginatedDiffs
+
+        DEFAULT_PAGE = 1
+        DEFAULT_PER_PAGE = 30
+
+        delegate :limit_value, :current_page, :next_page, :prev_page, :total_count,
+                 :total_pages, to: :paginated_collection
+
+        def initialize(merge_request_diff, page, per_page)
+          super(merge_request_diff, diff_options: nil)
+
+          @paginated_collection = load_paginated_collection(page, per_page)
+        end
+
+        private
+
+        def load_paginated_collection(page, per_page)
+          page ||= DEFAULT_PAGE
+          per_page ||= DEFAULT_PER_PAGE
+
+          relation.page(page).per([per_page.to_i, DEFAULT_PER_PAGE].min)
+        end
+      end
+    end
+  end
+end