Module Ocsigen_cache.​Dlist

module Dlist : sig..end

Doubly-linked lists with maximum number of entries, and (possibly) limited lifespan for entries.


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

Create a dlist. It takes the maximum length of the list as parameter. The optional ?timer parameter sets a maximum lifetime for elements (in seconds).

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