Add Gitlab::Utils::StrongMemoize

1 files changed, 31 insertions, 0 deletions

diff --git a/lib/gitlab/utils/strong_memoize.rb b/lib/gitlab/utils/strong_memoize.rb
new file mode 100644
index 00000000000..a2ac9285b56
--- /dev/null
+++ b/lib/gitlab/utils/strong_memoize.rb
@@ -0,0 +1,31 @@
+module Gitlab
+  module Utils
+    module StrongMemoize
+      # Instead of writing patterns like this:
+      #
+      #     def trigger_from_token
+      #       return @trigger if defined?(@trigger)
+      #
+      #       @trigger = Ci::Trigger.find_by_token(params[:token].to_s)
+      #     end
+      #
+      # We could write it like:
+      #
+      #     def trigger_from_token
+      #       strong_memoize(:trigger) do
+      #         Ci::Trigger.find_by_token(params[:token].to_s)
+      #       end
+      #     end
+      #
+      def strong_memoize(name)
+        ivar_name = "@#{name}"
+
+        if instance_variable_defined?(ivar_name)
+          instance_variable_get(ivar_name)
+        else
+          instance_variable_set(ivar_name, yield)
+        end
+      end
+    end
+  end
+end