Module type Irmin.ATOMIC_WRITE_STORE

Atomic-write stores.

Atomic write stores

Atomic-write stores are stores where it is possible to read, update and remove elements, with atomically guarantees.

type t

The type for atomic-write backend stores.

type key

The type for keys.

type value

The type for raw values.

val mem : t -> key -> bool Lwt.t

mem t k is true iff k is present in t.

val find : t -> key -> value option Lwt.t

find t k is Some v if k is associated to v in t and None is k is not present in t.

val set : t -> key -> value -> unit Lwt.t

set t k v replaces the contents of k by v in t. If k is not already defined in t, create a fresh binding. Raise Invalid_argument if k is the empty path.

val test_and_set : t -> key -> test:value option -> set:value option -> bool Lwt.t

test_and_set t key ~test ~set sets key to set only if the current value of key is test and in that case returns true. If the current value of key is different, it returns false. None means that the value does not have to exist or is removed.

Note: The operation is guaranteed to be atomic.

val remove : t -> key -> unit Lwt.t

remove t k remove the key k in t.

val list : t -> key list Lwt.t

list t it the list of keys in t.

type watch

The type of watch handlers.

val watch : t -> ?init:(key * value) list -> (key -> value Diff.t -> unit Lwt.t) -> watch Lwt.t

watch t ?init f adds f to the list of t's watch handlers and returns the watch handler to be used with unwatch. init is the optional initial values. It is more efficient to use watch_key to watch only a single given key.

val watch_key : t -> key -> ?init:value -> (value Diff.t -> unit Lwt.t) -> watch Lwt.t

watch_key t k ?init f adds f to the list of t's watch handlers for the key k and returns the watch handler to be used with unwatch. init is the optional initial value of the key.

val unwatch : t -> watch -> unit Lwt.t

unwatch t w removes w from t's watch handlers.

val close : t -> unit Lwt.t

close t frees up all the resources associated with t. Any operations run on a closed handle will raise Closed.

val clear : t -> unit Lwt.t

Clear the store. This operation is expected to be slow.