Implementation of the topicFilter module

topicFilter.ml

module TOPIC_FILTER = struct
  (* module TOPICFILTER : TOPIC_FILTER = struct *)
  module UnixSocketMap = Map.Make (String)

  let socketMap = ref UnixSocketMap.empty

  let addSocket topic socket =
    print_endline "Adding socket to topic";
    let sockets =
      try UnixSocketMap.find topic !socketMap with Not_found -> []
    in
    socketMap :=
      UnixSocketMap.add topic (List.append sockets [ socket ]) !socketMap

  let removeSocket topic socket =
    let sockets =
      try UnixSocketMap.find topic !socketMap with Not_found -> []
    in
    let sockets' = List.filter (fun s -> s <> socket) sockets in
    socketMap := UnixSocketMap.add topic sockets' !socketMap

  let getSockets topic =
    let sockets =
      try UnixSocketMap.find topic !socketMap with Not_found -> []
    in
    List.rev sockets
end