Fiber-local storage.
This storage is associated to the current fiber, just like thread-local storage is associated with the current thread.
See Moonpool.Task_local_storage
for more general information, as this is based on it.
NOTE : it's important to note that, while each fiber has its own storage, spawning a sub-fiber f2
from a fiber f1
will only do a shallow copy of the storage. Values inside f1
's storage will be physically shared with f2
. It is thus recommended to store only persistent values in the local storage.
include module type of struct include Moonpool.Task_local_storage end
type t = Moonpool__.Types_.ls_value array ref
Underlying storage for a task. This is mutable and not thread-safe.
A key used to access a particular (typed) storage slot on every task.
val new_key : init :(unit -> 'a ) -> unit -> 'a key
new_key ~init ()
makes a new key. Keys are expensive and should never be allocated dynamically or in a loop. The correct pattern is, at toplevel:
let k_foo : foo Task_ocal_storage.key =
Task_local_storage.new_key ~init:(fun () -> make_foo ()) ()
(* … *)
(* use it: *)
let … = Task_local_storage.get k_foo
get k
gets the value for the current task for key k
. Must be run from inside a task running on a runner.
val get_opt : 'a key -> 'a option
get_opt k
gets the current task's value for key k
, or None
if not run from inside the task.
val set : 'a key -> 'a -> unit
set k v
sets the storage for k
to v
. Must be run from inside a task running on a runner.
val with_value : 'a key -> 'a -> (unit -> 'b ) -> 'b
with_value k v f
sets k
to v
for the duration of the call to f()
. When f()
returns (or fails), k
is restored to its old value.
val get_current : unit -> t option
Access the current storage, or None
if not run from within a task.
Direct access to values from a storage handle