irmin-mirage-graphql 2.3.0

Branch Store

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 = branch

The type for keys.

type value = Hash.t

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 Irmin.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 Irmin.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 to t. Any operations run on a closed store will raise Closed.

val clear : t -> unit Lwt.t

clear t clears the store. This operation is expected to be slow.

module Key : sig ... end

Base functions on keys.

module Val : sig ... end

Base functions on values.

package irmin-mirage-graphql

Branch Store

Atomic write stores