# Module Ocsigen_cache.Dlist

    module Dlist: sig .. end

Doubly-linked lists with maximum number of entries and limited lifespan for entries.

    type 'a t

    type 'a node

    val create : ?timer:float -> int -> 'a t

    val add : 'a -> 'a t -> 'a option

Adds an element to the list, and possibly returns the element that has been removed if the maximum size was exceeded.

    val remove : 'a node -> unit

Removes an element from its list. If it is not in a list, it does nothing. If it is in a list, it calls the finaliser, then removes the element. If the finaliser fails with an exception, the element is removed and the exception is raised again.

    val up : 'a node -> unit

Removes the element from its list without finalising, then adds it as newest.

    val newest : 'a t -> 'a node option

    val oldest : 'a t -> 'a node option

    val size : 'a t -> int

    val maxsize : 'a t -> int

    val value : 'a node -> 'a

    val get_timer : 'a t -> float option

returns the timer of the Dlist

    val list_of : 'a node -> 'a t option

The list to which the node belongs

    val remove_n_oldest : 'a t -> int -> 'a list

remove the n oldest values (or less if the list is not long enough) ; returns the list of removed values

    val fold : ('b -> 'a -> 'b) -> 'b -> 'a t -> 'b

fold over the elements from the cache starting from the newest to the oldest

    val fold_back : ('b -> 'a -> 'b) -> 'b -> 'a t -> 'b

fold over the elements from the cache starting from the oldest to the newest

    val lwt_fold : ('b -> 'a -> 'b Lwt.t) -> 'b -> 'a t -> 'b Lwt.t

lwt version of fold

    val lwt_fold_back : ('b -> 'a -> 'b Lwt.t) -> 'b -> 'a t -> 'b Lwt.t

lwt version of fold_back

    val move : 'a node -> 'a t -> 'a option

Move a node from one dlist to another one, without finalizing. If one value is removed from the destination list (because its maximum size is reached), it is returned (after finalisation).

    val set_maxsize : 'a t -> int -> 'a list

change the maximum size ; returns the list of removed values, if any.

    val set_finaliser_before : ('a node -> unit) -> 'a t -> unit

set a function to be called automatically on a piece of data just before it disappears from the list (either by explicit removal or because the maximum size is exceeded)

    val get_finaliser_before : 'a t -> 'a node -> unit

    val set_finaliser_after : ('a node -> unit) -> 'a t -> unit

set a function to be called automatically on a piece of data just after it disappears from the list (either by explicit removal or because the maximum size is exceeded)

    val get_finaliser_after : 'a t -> 'a node -> unit