1 files changed, 49 insertions, 0 deletions
diff --git a/lib/argument_deduplication/argument.rb b/lib/argument_deduplication/argument.rb
new file mode 100644
index 000000000..60be6bca2
--- /dev/null
+++ b/lib/argument_deduplication/argument.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+module ArgumentDeduplication
+  class Argument
+    def self.from_value(value)
+      new(Digest::SHA256.base64digest(value), value)
+    end
+
+    attr_reader :content_hash, :value
+
+    def initialize(content_hash, value)
+      @content_hash = content_hash
+      @value = value
+    end
+
+    def push!
+      with_redis do |redis|
+        redis.multi do |transaction|
+          transaction.set("#{PREFIX}:value:#{content_hash}", value, ex: TTL)
+          transaction.incr("#{PREFIX}:refcount:#{content_hash}")
+          transaction.expire("#{PREFIX}:refcount:#{content_hash}", TTL)
+        end
+      end
+    end
+
+    def pop!
+      with_redis do |redis|
+        redis.decr("#{PREFIX}:refcount:#{content_hash}")
+
+        redis.watch("#{PREFIX}:refcount:#{content_hash}") do
+          if redis.get("#{PREFIX}:refcount:#{content_hash}").to_i <= 0
+            redis.multi do |transaction|
+              transaction.del("#{PREFIX}:refcount:#{content_hash}")
+              transaction.del("#{PREFIX}:value:#{content_hash}")
+            end
+          else
+            redis.unwatch
+          end
+        end
+      end
+    end
+
+    private
+
+    def with_redis(&block)
+      Sidekiq.redis(&block)
+    end
+  end
+end