1 files changed, 48 insertions, 0 deletions
diff --git a/lib/gitlab/ci/config/yaml/loader.rb b/lib/gitlab/ci/config/yaml/loader.rb
new file mode 100644
index 00000000000..924a1f2e46b
--- /dev/null
+++ b/lib/gitlab/ci/config/yaml/loader.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Ci
+    class Config
+      module Yaml
+        class Loader
+          AVAILABLE_TAGS = [Config::Yaml::Tags::Reference].freeze
+          MAX_DOCUMENTS = 2
+
+          def initialize(content, project: nil)
+            @content = content
+            @project = project
+          end
+
+          def to_result
+            Yaml::Result.new(config: load!, error: nil)
+          rescue ::Gitlab::Config::Loader::FormatError => e
+            Yaml::Result.new(error: e)
+          end
+
+          private
+
+          attr_reader :content, :project
+
+          def ensure_custom_tags
+            @ensure_custom_tags ||= begin
+              AVAILABLE_TAGS.each { |klass| Psych.add_tag(klass.tag, klass) }
+
+              true
+            end
+          end
+
+          def load!
+            ensure_custom_tags
+
+            ::Gitlab::Config::Loader::MultiDocYaml.new(
+              content,
+              max_documents: MAX_DOCUMENTS,
+              additional_permitted_classes: AVAILABLE_TAGS,
+              reject_empty: true
+            ).load!
+          end
+        end
+      end
+    end
+  end
+end